Skip to Main Content

Abstract

This chapter describes sandstone sills intruded into the middle Miocene Pil´sk Suite, which are well exposed along a continuously exposed 8-km (5-mi) section on the southeast coast of Schmidt Peninsula, Sakhalin (Russian Far East). This suite forms part of a relatively thin Neogene succession (probably no more than 1100 m thick [3608 ft]), which unconformably overlies Cretaceous deposits. The succession was deposited on a topographic high, which marks the Mesozoic outer arc high and is now deformed within a large-scale dextral strike-slip fault system, part of the Eurasia- North America plate boundary. The Pil´sk Suite is dominated by organic-rich biosiliceous rocks (opoka, porcelanite, and rare chert). Within this siliceous succession are abundant brown, well-cemented sandstones, subparallel to bedding, with erosional top and bottom contacts. Their changing stratigraphic position makes correlation across distances greater than about 10 m (33 ft) difficult. They are interpreted as having an injected origin.

Trains of upright to gently inclined folds deform the pre-late Miocene succession, including the brown sandstones. The vergence of these structures, and the transport direction of associated thrust faults, is generally toward the southwest. The injected sandstone sills were clearly cemented prior to brittle deformation. Deformation is concentrated into high-strain zones spaced approximately 1 km (0.6 mi) apart, which are probably part of a large flower structure. Almost all the sandstone sills are found within these zones, adding several tens of meters to the stratigraphic thickness. Given the relatively thin post-middle Miocene succession, it is likely that this injection resulted in coeval deformation of the sediment surface.

Introduction

Rationale

This chapter is based on industrially funded fieldwork conducted on the southeast coast of the Schmidt Peninsula, northern Sakhalin (Figures 1, 2) in September 1998. Our aim was to collect and collate sedimen- tological and structural data as part of a much larger study of the Cenozoic facies distribution, paleogeogra- phy, and tectonic evolution of Sakhalin. The main focus of the study was the middle Miocene because this is the main source rock interval and is also the time of onset of deposition in the paleo-Amur delta, which contains the main reservoir units on Sakhalin (Davies et al., 2005). Schmidt Peninsula was an important focus for the study, partly because of its position adjacent to two offshore license areas (Sakhalin IV and V), but more importantly, because it exhibits long Neogene sections and rapid lateral facies changes.

Figure 1.

Geology and setting of Sakhalin. (A) The area around the Sea of Okhotsk showing the relationship of the central Sakhalin Fault system to Hokkaido and the active Japan-Kuril subduction zone. (B) Geology of Sakhalin (adapted from Vereshchagin et al., 1969) showing the extent of Neogene deposits. The arrow shows the location of the detailed map of the southeast Schmidt Peninsula section (Figure 2).

Figure 1.

Geology and setting of Sakhalin. (A) The area around the Sea of Okhotsk showing the relationship of the central Sakhalin Fault system to Hokkaido and the active Japan-Kuril subduction zone. (B) Geology of Sakhalin (adapted from Vereshchagin et al., 1969) showing the extent of Neogene deposits. The arrow shows the location of the detailed map of the southeast Schmidt Peninsula section (Figure 2).

Figure 2.

Detailed map of the southeast Schmidt Peninsula section (see inset for location). Exposure is near continuous from Mys Poklonnaya to the mouth of the Bolshoi Langri at Zim. Farther to the northeast from here, a security zone was not visited. Inset shows the positions of the north (N), west (W), and southeast (SE) Schmidt sections (see Figure 4). The camp is the location of the start of the mapped section (survey station T).

Figure 2.

Detailed map of the southeast Schmidt Peninsula section (see inset for location). Exposure is near continuous from Mys Poklonnaya to the mouth of the Bolshoi Langri at Zim. Farther to the northeast from here, a security zone was not visited. Inset shows the positions of the north (N), west (W), and southeast (SE) Schmidt sections (see Figure 4). The camp is the location of the start of the mapped section (survey station T).

The area was also important as one of the few onshore sections where Neogene turbidites had been reported. The work described in this chapter came from the realization that the turbidites were, in fact, layer- parallel injectites.

Clastic-injection structures have been extensively reviewed (see, for example, Newsom, 1903; Taylor, 1982; Jolly and Lonergan, 2002). In outcrop, sandstone dikes and strongly transgressive injected sand sheets are easy to spot from their strongly discordant relationship with bedding. In well-exposed settings, it is clear that clastic sills are also common, both as offshoots from clastic dikes and as concordant segments linking different dikes. These broadly bedding-parallel injected features are much harder to identify. Because many injected sand systems are associated with deep-marine strata, injected sandstone sills could easily be mistaken for structureless sand beds deposited by high-density turbidity currents (Lowe, 1982).

This chapter has three aims, specifically, (1) to document the occurrence of well-exposed sandstone sills in the Miocene of Schmidt Peninsula, northern Sakhalin;(1) to use this example to develop criteria that aid in the recognition of sandstone sills in less well-exposed outcrop settings and in core; and (3) to discuss the implications of the Sakhalin example for timing of injection and lithification, and for surface deformation in earthquake zones.

Method

Our study occurred under constraints imposed by the Russian authorities. We were permitted to observe the section and to take notes, structural measurements, and photographs, but not to collect samples. Hence, all lithological description in this work is based purely on hand-specimen investigation.

Mapping

The exposed section stretches for 8 km (5 mi) from Mys Poklonnaya to the mouth of the River Bolshoi Langri at Zim (Figure 2). Survey positions were fixed by global positioning system and checked against a Russian 1:50,000 topographic map, which was also the source of the topographic information in Figure 2. Exposure was nearly continuous along the coast, with cliffs about 50 m (164 ft) high (in a few places reaching almost 100 m; Figure 3). The beach is very narrow along the whole section, so although we photographed the whole exposure, we have no large-scale views, and many of the mesoscale photographs have distorted perspective.

Figure 3.

View north along the southeast coast of Schmidt Peninsula from Survey Station M. Note the dark (graygreen) Cretaceous sandstones in the foreground with the pale cliffs of the siliceous Pil’sk Suite behind; the higher cliffs in the middle ground reach 100 m (330 ft) above sea level. At the far end of the section, the darker, northwest-southeast-trending ridge formed of Mesozoic igneous rocks can just be seen, approximately 8 km (5 mi) away.

Figure 3.

View north along the southeast coast of Schmidt Peninsula from Survey Station M. Note the dark (graygreen) Cretaceous sandstones in the foreground with the pale cliffs of the siliceous Pil’sk Suite behind; the higher cliffs in the middle ground reach 100 m (330 ft) above sea level. At the far end of the section, the darker, northwest-southeast-trending ridge formed of Mesozoic igneous rocks can just be seen, approximately 8 km (5 mi) away.

Structure

Dip and strike of bedding were taken at regular intervals and on the limbs of all folds; fault orientations were also recorded. In the 8.43-km (5.23-mi) section (Figure 2) from (DM.151a) in the north to (DM.151T) in the south, there are 34 fixed points with a mean spacing of 248 m (813 ft). These points were used to construct a cross section (Figure 4) as follows:

Figure 4.

Cross sections of the exposure of the Pil’sk Suite on the southeast coast of the Schmidt Peninsula. For location of the section line, see Figure 2; note that survey station letters on the section correspond to those on the map.

Figure 4.

Cross sections of the exposure of the Pil’sk Suite on the southeast coast of the Schmidt Peninsula. For location of the section line, see Figure 2; note that survey station letters on the section correspond to those on the map.

  • 1)

    A dog-leg section line was constructed from (DM.151T) to (DM.151F) on a bearing of 17° and from (DM.151F) to (DM.151α) on a bearing of 41°.

  • 2)

    Positions of the fixed points were projected perpendicularly onto the section lines. No point lies more than 150 m (492 ft) from the section; the mean distance from the section is 70 m (229 ft).

  • 3)

    All bedding dips were converted to apparent dips in the line of section. These are shown on the section as solid bars.

  • 4)

    Positions of all folds between fixed points were extrapolated from photographs and field sketches.

Sedimentology

Sedimentological logs were measured on every accessible exposed section longer than 20 m (66 ft); we measured six logs totaling 286 m (938 ft). The longest, and the one on which most of our large-scale observation is based, was 168 m (551 ft).

Geological Background

Tectonic Setting of Sakhalin

During the Cretaceous and earliest Tertiary, Sakhalin formed part of a forearc above the west-subducting Pacific plate, with a corresponding arc along the line of the Sikhote Al´in Ridge on the Russian mainland (Figure 1A) (Zonenshain et al., 1990). Subduction ceased during the Late Cretaceous or Paleogene as the arc-arc cusp (now located off Hokkaido) migrated south; the Kuril volcanic arc was established by the late Oligocene. Sakhalin was now in a retroarc position, with major strike-slip faulting established by the Miocene (Fournier et al., 1994; Weaver et al., 2004). This dextral strike-slip system persists to the present day, with frequent large earthquakes (Ivaschenko et al., 1997); the fault system forms part of the Eurasia-North America plate boundary (Seno et al., 1996).

Figure 1 shows an outline of the geology of Sakhalin, showing the position of Schmidt Peninsula in the extreme north; details of the area and section are shown in Figures 2 and 3. The tectonic evolution of the Schmidt Peninsula is not well understood, but it appears to be underlain by Mesozoic rocks, which formed part of the accretionary complex. The crest of the subduction complex (former outer arc high) is marked by a gravity and magnetic anomaly. This runs along the northeast side of Schmidt Peninsula and continues offshore to the southeast. To the south, subduction complex rocks are exposed in the East Sakhalin mountains and the area to the east of Yuzhno-Sakhalinsk (Figure 1). The main dextral strike-slip fault system (the Sakhalin-Hokkaido shear zone) exploits the subduction-generated north- south structural grain and also passes through Schmidt Peninsula.

Previous Work

Little research has been conducted on the southeast coast of the Schmidt Peninsula, except reconnaissance lithological and biostratigraphic work (Vereshchagin et al., 1969). The reconnaissance work was used mainly to assign stratigraphic ages and suite names to the exposed rocks. This has been supplemented by work done by geologists from Okha under the leadership of B. A. Salnikov in the 1980s, some of which have been incorporated into unpublished reports, which have been kept confidential for commercial reasons.

Stratigraphic names of suites in the Southeast part of the Schmidt Peninsula.*

Table 1.
Stratigraphic names of suites in the Southeast part of the Schmidt Peninsula.*
StageSubstageSuiteThicknessInjected Sands
Pliocene(Undefined)Mattituk<50 mNone
MioceneTortonian - MessinianMayamraf´<50 mNone
Early-middle TortonianLocal unconformity in southeast Schmidt
SerravallianKaskad>200 mSome thin sheets
Langhian - Serravallian(?)Pil´sk>500 mAbundant
Aquitanian-BurdigalianTymsk>150 mSome thin sheets
PaleogeneWidespread unconformity on Schmidt Peninsula
CretaceousMaastrichtian(?)Slavyan>175 mNone
StageSubstageSuiteThicknessInjected Sands
Pliocene(Undefined)Mattituk<50 mNone
MioceneTortonian - MessinianMayamraf´<50 mNone
Early-middle TortonianLocal unconformity in southeast Schmidt
SerravallianKaskad>200 mSome thin sheets
Langhian - Serravallian(?)Pil´sk>500 mAbundant
Aquitanian-BurdigalianTymsk>150 mSome thin sheets
PaleogeneWidespread unconformity on Schmidt Peninsula
CretaceousMaastrichtian(?)Slavyan>175 mNone

*The Pil´sk Suite, where most of the injected sand structures occur, is highlighted. Note that the basic Russian lithostratigraphic unit is the cBuma (Svita or Suite). This is “formation,” but the concepts are different because the suite contains an implication that the unit has a particular age range. To emphasize this difference, we have used the word “suite” throughout when referring to stratigraphic units. For clarity, we have omitted the feminine adjectival ending (-cKaЯl [-Skaya]), which is a formal part of every suite name.

Stratigraphy

For the purposes of this chapter, we have used the suite names supplied by Salnikov in the field. The stratigraphy of Schmidt Peninsula is summarized in Table 1 and Figure 5. Brief descriptions of the stratigraphic units are given below. The stratigraphy and structure of the Pil´sk Suite are then discussed in greater detail because this unit is host to most of the injected sands.

Figure 5.

Stratigraphic columns for the Schmidt Peninsula area (for locations, see Figure 2, inset) based on Cambridge Arctic Shelf Programme (CASP) fieldwork; a review of Russian stratigraphic literature by L. G. Voronova and J. L.Wardell (1991, personal communication); and from B. A. Salnikov (1998, personal communication). The suites are Kak = Kaskad; Mac = Machigar; Mat = Mattituk; May = Mayamraf; Plk = Pil’sk; Pom = Pomyr; Tym = Tymsk; Ven = Vengiriy.

Figure 5.

Stratigraphic columns for the Schmidt Peninsula area (for locations, see Figure 2, inset) based on Cambridge Arctic Shelf Programme (CASP) fieldwork; a review of Russian stratigraphic literature by L. G. Voronova and J. L.Wardell (1991, personal communication); and from B. A. Salnikov (1998, personal communication). The suites are Kak = Kaskad; Mac = Machigar; Mat = Mattituk; May = Mayamraf; Plk = Pil’sk; Pom = Pomyr; Tym = Tymsk; Ven = Vengiriy.

Basement Slavyan Suite (Cretaceous)

The basement is exposed at Survey Station M (Figure 2), where 175 m (574 ft) of succession crop out in a south-dipping block, with a faulted northern margin against the Pil´sk Suite, and an unconformable southern margin below the Tymsk suite. Mesozoic ultrabasic and ultramafic igneous rocks crop out beyond the northern end of the section, but this area was classed as a security zone and was not accessible to us. The Slavyan suite consists of green, poorly sorted, dominantly crossbedded sandstone; these rocks were deposited as part of a fluviolacustrine system with a southerly transport direction.

Tymsk Suite (Early Miocene)

At least 150 m (492 ft) of Tymsk suite are exposed south of Survey Station M, where it unconformably overlies the Cretaceous; there are no exposed contacts with any other unit. The suite has a basal sand member, above which it consists largely of biosiliceous rocks. The facies suggest that these sediments were deposited in an open- marine setting after an initial transgression across a subaerial unconformity.

Pil´sk Suite (Middle Miocene)

This is well exposed along most of the length of the section (Figure 3). No stratigraphic contacts with other suites are exposed; this, combined with the intense brittle and ductile deformation, makes the thickness difficult to assess. However, the maximum thickness of continuous section is 500 m (1640 ft), between survey stations F and G. The unit is dominated by biosiliceous deposits with subordinate sandstones, including the injected sand sheets that are the main topic of this chapter.

Kaskad Suite (Middle-Late Miocene)

This is only exposed south of the section shown in Figure 2, where it is exposed as a red-brown weathering, predominantly mudstone-dominated succession. At least 200 m (660 ft) of strata are exposed, comprising silty mudstone resulting from clastic suspension fallout in a marine environment, with rare, slumped turbidites and intrusive sands. It is interpreted as a slope deposit. These sediments were later crosscut by thin intrusive sand bodies.

Mayamraf Suite (Late Miocene)

Like the Kaskad suite, this suite is only exposed in the far south of the section; only about 15 m (49 ft) of Mayamraf suite is exposed. Poor exposure on either side of this cliff obscures its relationships to the younger Mattituk and older Kaskad suites (Table 1). This unit is a mixed clastic and siliceous facies, probably deposited in a marine environment with a slow clastic sedimentation rate and significant bioturbation. As far as it is possible to tell, the succession is flat lying and undeformed.

Mattituk Suite (Pliocene)

Like the underlying suite, the Mattituk suite is exposed south of the area; poor exposure obscures its relationship to the older Mayamraf suite (Table 1). The suite is probably not more than 50 m (164 ft) thick and is dominated by cross-bedded, unlithified sand. The litho- facies and the absence of marine fauna suggest that the Mattituk suite was deposited as part of a sandy fluvial system. The suite is flat lying and undeformed.

Discussion

Each of these stratigraphic units is considerably thinner than equivalent units elsewhere on Sakhalin. The Paleogene is absent, which is in accord with other areas of east Sakhalin. The early-middle Miocene succession is probably of the order of 1000 m (3300 ft), thinner than some other localities on Sakhalin, but not dramatically so. However, the late Miocene-Pliocene is very thin (probably not more than 100 m [330 ft]), compared to the 500–1000 m (1640–3300 ft) of correlative Nutov Suite exposed to the south and west of this area, much less than elsewhere on Sakhalin. This suggests that the Schmidt Peninsula has been a persistent topographic high, based on the old accretionary complex.

The absence of the Paleogene can be ascribed to relict paleotopography on the former outer arc high. This was drowned and overwhelmed at the beginning of the Miocene, but the area was either relatively remote or protected from clastic input. The thin, late Neogene section probably reflects late Miocene-Pliocene syndepositional uplift and thinning or onlap onto the high area. This suggestion is discussed in greater detail below.

As well as variation in stratigraphic thickness, there is variation in clastic input into the southeast Schmidt Peninsula area at various times. During the Tymsk and Pil´sk times, the area was mostly protected from clastic sedimentation, and significant quantities of biosili- ceous sediment accumulated. Limited clastic input began during deposition of the Mayamraf suite, allowing the formation of mixed siliceous-clastic facies. During Kaskad and Mattituk times, clastic deposition swamped background siliceous sedimentation.

Sedimentology of the Pil´Sk Suite

Sedimentary facies

Thirteen sedimentary facies were identified; these are listed and described in Table 2. 0f these facies, the siliceous rocks (facies P1, P2, P3, and P4) are the most volumetrically important (approximately 75%) and indicate a high level of marine biogenic productivity in an environment protected from clastic input. Facies P5 and P6 also contain large quantities of biosiliceous material, but with some clastic content. The rare tuffs (P7) indicate that volcanism was active in the region.

As in other areas within and around the fringes of the paleo-Amur delta, mud (P8) is extremely uncommon (Davies et al., 2005). The coarse clastic facies (P9–P12) form about 23% of the section, but only the white and brown sandstone facies are volumetrically important. The four sand facies each have a different origin (Table 3). Both the white sand facies (P10) and the glauconitic sandstone facies (P12) appear to have remained in situ following deposition by submarine currents. The muddy sand facies (P9) is also likely to have been originally deposited by submarine currents, but the associated synsedimentary folding indicates that it was subsequently affected by gravitational sliding.

Sedimentary facies of the middle Miocene Pil´sk Suite, southeast Schmidt Peninsula.*

Table 2.
Sedimentary facies of the middle Miocene Pil´sk Suite, southeast Schmidt Peninsula.*
No.NameThickness (m)DescriptionInterpretation
P1Opoka0.15–1.0Pale weathering, brown when fresh; hydrocarbon smell; irregular and undulating top and bottom boundaries; micrometer- to millimeter-scale lamination; may contain fish scales and benthic and planktonic forams;can be bioturbated.Background biosiliceous sedimentation.
P2Porcellanite0.01–0.2Weathers medium gray, dark gray when fresh; strong hydrocarbon smell; laminated with a moderate to well-developed fissility; can be very finely laminated, can be foram bearing; can have stylolites; can be bioturbated.Biosiliceous sedimentation, with higher grade diagenesis than P1.
P3Chert0.01–0.1Uncommon facies;dark brown-black, commonly red weathering; nodular or banded discontinuous layers; can be associated with glauconite.Biosiliceous sedimentation, with higher grade diagenesis than P2.
P4Siliceous clay-mud0.03–0.5Very dark brown, sapropelic(?);varying siliceous content;slight to strong hydrocarbon smell; uncommonly laminated; can be bioturbated; no forams observed.High productivity, low oxygen levels, suspension sedimentation.
P5Sandy opoka0.1–1.5Uncommon facies; laminated opoka, with floating sand grains (generally vfs grade).Bioturbation, slump mixing, or mixing; from fluvial plume;low clastic input.
P6Glauconitic opoka0.1 –0.25Uncommon facies; low concentrations of dispersed glauconite as floating grains in blocky opoka or within forams.Mixing, as P5, but with lower clastic sedimentation rate.
P7Tuff0.005–0.1Blue-gray; sticky; can contain grains up to sand grade, some of which may be crystals.Diagenetically altered airfall crystal tuff.
P8Mudstone0.005–0.25Gray; may contain organic matter; can be contorted; impersistent or can pass laterally into a layer of clasts (commonly very irregular).Suspension deposition.
P9Muddy sandstone22.0Chaotic with detached sand balls.Submarine slide deposits.
P10White sandstone0.25–2.5Poorly consolidated; erosive based; internal scours; cross-bedded; abundant clay clasts; parallel laminated in places; can be amalgamated; moderately sorted; uncommon load-cast base.Current deposition in delta progradation events (Amur sands).
11Brown sandstone0.02–3.0Brown weathering; very well cemented; well sorted, predominantly fine sand, subsidiary medium-coarse; carbonate cement (white); erosive base and top; sandstones generally ungraded, but coarse tail (both normal and inverse) present; grading generally only in thicker beds; grooves on base of some beds; dikes and sills and other intrusive structures observed.Subvertical and subhorizontal sand intrusion.
P12Glauconitic sandstone0.1 –0.75Associated with phosphate, either as a bed or as nodules; patchy distribution; where associated with clastics, it is bioturbated fine- medium sandstone with glauconite in burrows; uncommon glauconite in sandy laminated porcellanite.Either slow sedimentation in wave-worked environment, or reworked downslope by possible debris flow.
P13Concretions0.02–1.0Spherical to elongate bedding-parallel concretions; CaCO3(?) or other carbonate; undulating top and bottom; small irregular-elongate concretions associated with tuff; spherical concretions associated with siliceous units; uncommon association with intrusive sandstones, but never cut by them; weatherlike sandstone; brecciated texture in some; some have calcite veins.Relatively early (precompaction) diagenesis.
No.NameThickness (m)DescriptionInterpretation
P1Opoka0.15–1.0Pale weathering, brown when fresh; hydrocarbon smell; irregular and undulating top and bottom boundaries; micrometer- to millimeter-scale lamination; may contain fish scales and benthic and planktonic forams;can be bioturbated.Background biosiliceous sedimentation.
P2Porcellanite0.01–0.2Weathers medium gray, dark gray when fresh; strong hydrocarbon smell; laminated with a moderate to well-developed fissility; can be very finely laminated, can be foram bearing; can have stylolites; can be bioturbated.Biosiliceous sedimentation, with higher grade diagenesis than P1.
P3Chert0.01–0.1Uncommon facies;dark brown-black, commonly red weathering; nodular or banded discontinuous layers; can be associated with glauconite.Biosiliceous sedimentation, with higher grade diagenesis than P2.
P4Siliceous clay-mud0.03–0.5Very dark brown, sapropelic(?);varying siliceous content;slight to strong hydrocarbon smell; uncommonly laminated; can be bioturbated; no forams observed.High productivity, low oxygen levels, suspension sedimentation.
P5Sandy opoka0.1–1.5Uncommon facies; laminated opoka, with floating sand grains (generally vfs grade).Bioturbation, slump mixing, or mixing; from fluvial plume;low clastic input.
P6Glauconitic opoka0.1 –0.25Uncommon facies; low concentrations of dispersed glauconite as floating grains in blocky opoka or within forams.Mixing, as P5, but with lower clastic sedimentation rate.
P7Tuff0.005–0.1Blue-gray; sticky; can contain grains up to sand grade, some of which may be crystals.Diagenetically altered airfall crystal tuff.
P8Mudstone0.005–0.25Gray; may contain organic matter; can be contorted; impersistent or can pass laterally into a layer of clasts (commonly very irregular).Suspension deposition.
P9Muddy sandstone22.0Chaotic with detached sand balls.Submarine slide deposits.
P10White sandstone0.25–2.5Poorly consolidated; erosive based; internal scours; cross-bedded; abundant clay clasts; parallel laminated in places; can be amalgamated; moderately sorted; uncommon load-cast base.Current deposition in delta progradation events (Amur sands).
11Brown sandstone0.02–3.0Brown weathering; very well cemented; well sorted, predominantly fine sand, subsidiary medium-coarse; carbonate cement (white); erosive base and top; sandstones generally ungraded, but coarse tail (both normal and inverse) present; grading generally only in thicker beds; grooves on base of some beds; dikes and sills and other intrusive structures observed.Subvertical and subhorizontal sand intrusion.
P12Glauconitic sandstone0.1 –0.75Associated with phosphate, either as a bed or as nodules; patchy distribution; where associated with clastics, it is bioturbated fine- medium sandstone with glauconite in burrows; uncommon glauconite in sandy laminated porcellanite.Either slow sedimentation in wave-worked environment, or reworked downslope by possible debris flow.
P13Concretions0.02–1.0Spherical to elongate bedding-parallel concretions; CaCO3(?) or other carbonate; undulating top and bottom; small irregular-elongate concretions associated with tuff; spherical concretions associated with siliceous units; uncommon association with intrusive sandstones, but never cut by them; weatherlike sandstone; brecciated texture in some; some have calcite veins.Relatively early (precompaction) diagenesis.

*Facies P11 (injected sands) is highlighted.

Main features of the four sandstone facies in the Pil´sk Suite in the southeast part of the Schmidt Peninsula.

Table 3.
Main features of the four sandstone facies in the Pil´sk Suite in the southeast part of the Schmidt Peninsula.
Type of StructureWhite Sand (Facies P10)Glauconitic Sandstone (Facies P12)Muddy Sandstone (Facies P9)Brown Sandstone (Facies P11)
Current structuresParallel and cross-lamination,cross-beddingUncommon parallel laminationSynsedimentary slump nosesPoorly developed parallel lamination, tool marks (which can be on top of the unit)
Erosional structuresInternal scours and erosive basesNone seenNone seenErosive bases and tops, rip-up clasts at top and bottom of layers
GradingSmall-scale normal gradingNone seenNone seenNormal-inverse coarse-tail grading
Biogenic contentOrganic detritusBioturbatedNone seenNone seen
CementationUnlithifiedWell lithifiedPoorly lithifiedTight
InterpretationIn-situ deposits of marine currentsIn-situ deposits of marine currentsPostdeposition sediment sliding of marine depositsPostdepositional sand intrusion
Type of StructureWhite Sand (Facies P10)Glauconitic Sandstone (Facies P12)Muddy Sandstone (Facies P9)Brown Sandstone (Facies P11)
Current structuresParallel and cross-lamination,cross-beddingUncommon parallel laminationSynsedimentary slump nosesPoorly developed parallel lamination, tool marks (which can be on top of the unit)
Erosional structuresInternal scours and erosive basesNone seenNone seenErosive bases and tops, rip-up clasts at top and bottom of layers
GradingSmall-scale normal gradingNone seenNone seenNormal-inverse coarse-tail grading
Biogenic contentOrganic detritusBioturbatedNone seenNone seen
CementationUnlithifiedWell lithifiedPoorly lithifiedTight
InterpretationIn-situ deposits of marine currentsIn-situ deposits of marine currentsPostdeposition sediment sliding of marine depositsPostdepositional sand intrusion

Interpretation of the fourth facies, the brown sandstones (P11), is more controversial. This facies comprises brown, well-cemented, fine sandstone. Most beds are approximately bedding parallel, and there are some obvious sandstone dikes with the same composition and appearance as this facies. These had been reported as turbidites, but there are several problems with this interpretation.

Grading

Many of the sandstones have angular clasts of siliceous material at both the bottom and top of the layer (coarse tail grading; Figure 6). This gives a grading profile of normal to inverse, whereas turbidites commonly exhibit either normal grading, inverse grading, or inverse-to-normal grading (Lowe, 1982).

Figure 6.

(A) Block from the basal part of a brown sand unit containing angular clasts of siliceous sediment; pencil for scale. (B) The top of a brown sandstone unit (inverted in the steep limb of a fold) containing similar angular siliceous clasts (arrowed); hammer for scale.

Figure 6.

(A) Block from the basal part of a brown sand unit containing angular clasts of siliceous sediment; pencil for scale. (B) The top of a brown sandstone unit (inverted in the steep limb of a fold) containing similar angular siliceous clasts (arrowed); hammer for scale.

Grain Size

Excluding the biosiliceous intraclasts, these sandstones are dominated by fine sand-grade sediment with minor quantities of medium to coarse sand-grade material. No grading of the sand was observed.

Sedimentary Structures

The only structures present are crude, parallel lamination and grooves on the bases (Figure 7) and, in one case, the top of the units. No ripples, cross laminae, or other structures were generated at a loose boundary in any of the brown sandstones. No features resembled amalgamation surfaces.

Figure 7.

Grooves on the base of a brown sandstone unit; pencil for scale.

Figure 7.

Grooves on the base of a brown sandstone unit; pencil for scale.

Mirror Stratigraphy

The color and texture of the siliceous rocks immediately above and below sandstone units are commonly identical, with no hint of asymmetry (e.g., hemipelagic muds below the sand and turbidite muds above: Stow, 1985).

Unit Geometry

Finally, and most conclusively, every single sandstone bed logged either

  • 1)

    changed stratigraphic horizon in the scale of the exposure (Figure 8), or

  • 2)

    had a demonstrably erosional upper surface (Figure 9), or

  • 3)

    anastomosed (Figure 10), or

  • 4)

    4) terminated abruptly (Figure 11), or

  • 5)

    had all four of the above characteristics

Figure 8.

Photograph and interpretive sketch of an injected sand unit that changes direction in a series of 90° bends before terminating abruptly; injected sands are shown in yellow; scale is indicated on sketch.

Figure 8.

Photograph and interpretive sketch of an injected sand unit that changes direction in a series of 90° bends before terminating abruptly; injected sands are shown in yellow; scale is indicated on sketch.

Figure 9.

Erosive top of a sandstone unit; pencil for scale.

Figure 9.

Erosive top of a sandstone unit; pencil for scale.

Figure 10.

Brown sandstone unit changing from a dike to an anastomosing sill, with associated deformation along its edges; scale on photograph. The line drawing shows intrusive sand units (brown) in host siliceous sediments (gray); note that many small sand intrusions (centimeter scale) have been left off this drawing.

Figure 10.

Brown sandstone unit changing from a dike to an anastomosing sill, with associated deformation along its edges; scale on photograph. The line drawing shows intrusive sand units (brown) in host siliceous sediments (gray); note that many small sand intrusions (centimeter scale) have been left off this drawing.

Figure 11.

Abrupt termination of intrusive sandstone units; figure for scale.

Figure 11.

Abrupt termination of intrusive sandstone units; figure for scale.

Such structures cannot be produced by any depo- sitional process. The most likely alternative interpretation to the previous turbidite interpretation of these sediments is that both the bedding-parallel and crosscutting brown sandstones comprise a single facies. These represent a huge complex of intrusive sandstone sills and dikes. The normal-inverse grading profile is formed by rip-up clasts of the host rock incorporated into the boundary layers of the sands as they were intruded. The concentration of xenoliths along the margins of these bodies suggests that there may be an analogy with igneous intrusions, which display a similar pattern, but that is beyond the scope of this chapter. Other features of the facies, such as parallel lamination and grooves and the absence of ripples and fossils, are compatible with this interpretation because they have been documented from intrusive sands elsewhere (e.g., Taylor, 1982).

Facies Associations

The facies were grouped into four facies associations (Table 4). Association PA is volumetrically dominant, reflecting the high biogenic productivity at this time. Almost all the injected sands occur within well- defined units of association PB as sills with linking dikes. These facies association units have a mean thickness of 4.25 m (13.9 ft); within the units, individual injected bodies in these units have a mean thickness of 0.32 m (1.04 ft). Most of the injected sand units occur between survey stations I and G and between stations C and B (Figures 2,4), in zones of intense folding (i.e., high strain). Where injected sand bodies occur as minor components of other associations, they tend to occur as low-angle sheets with an irregular trajectory oblique to bedding (angles of 5–15°; Figure 12).

Figure 12.

Injected sand sheet cutting obliquely through biosiliceous rocks of association PA (see Table 4 in text); figure for scale.

Figure 12.

Injected sand sheet cutting obliquely through biosiliceous rocks of association PA (see Table 4 in text); figure for scale.

Depositional facies associations of the middle Miocene Pil´sk Suite, southeast Schmidt Peninsula.*

Table 4.
Depositional facies associations of the middle Miocene Pil´sk Suite, southeast Schmidt Peninsula.*
AssociationsFaciesInterpretationEstimated Volume (%)
PAP1, P2 and P4 ±P13, ±P7, (±P3), (±P5),(±P6),l±P1lBackground biogenic sedimentation75
PBPH. P1, P2 and P4 (±P5), (±P13)Intrusive sand complexes in siliceous country rock15
PCP8, P9 and P10 l±P11lDelta progradation and gravity slides8
PDP12, P1, P2 and P3Authigenic glauconite formation in conditions of slow sedimentation2
AssociationsFaciesInterpretationEstimated Volume (%)
PAP1, P2 and P4 ±P13, ±P7, (±P3), (±P5),(±P6),l±P1lBackground biogenic sedimentation75
PBPH. P1, P2 and P4 (±P5), (±P13)Intrusive sand complexes in siliceous country rock15
PCP8, P9 and P10 l±P11lDelta progradation and gravity slides8
PDP12, P1, P2 and P3Authigenic glauconite formation in conditions of slow sedimentation2

*Intrusive sand facies association (PB) is highlighted. The volume estimates are for the whole suite as exposed on the Southeast Schmidt Peninsula section.

The injected sand complexes (association PB) form units from 1 to 10 m (3.3 to 33 ft) thick. Not only do individual sheets change level in the stratigraphy, but whole units also transgress bedding. From initial examination of the cliff sections, it was clear that correlation across distances of more than approximately 10 m (33 ft) would be extremely difficult. We tested this by logging two sections out from the core of an anticline, where the start point of both sections was the same, and the tops of the two sections were 140 m (459 ft) apart (Figure 13). At this mean spacing of 70 m (229 ft), the facies associations could be traced. However, no individual injected sand body could be reliably traced from one section to another. This point is illustrated by the difference in number of individual injected sand bodies between sections.

Figure 13.

Correlation of measured sections on either side of the anticline at locality (DM.151/2). Note that although both siliceous and white sandstone units can be traced, correlation of individual beds is obscured by prolific intrusive sandstones. The difference in stratigraphic thickness between the sections is approximately the same as the change in thickness of the intrusive sandstones. The numbers by each log refer to the total number of individual sand intrusions in each unit.

Figure 13.

Correlation of measured sections on either side of the anticline at locality (DM.151/2). Note that although both siliceous and white sandstone units can be traced, correlation of individual beds is obscured by prolific intrusive sandstones. The difference in stratigraphic thickness between the sections is approximately the same as the change in thickness of the intrusive sandstones. The numbers by each log refer to the total number of individual sand intrusions in each unit.

It is also worth noting that parts of the Pil´sk Suite, which contain concretions, tend not to have sand intrusions (Figure 5). Where the two features do occur together, however, sandstone intrusions can be seen threading around concretions. This demonstrates that carbonate concretions were present prior to sand intrusion.

The Source of the Intruded Sandstones

It is difficult to suggest a possible source for these sandstones. Given the thin overburden (not more than a few hundred meters), an origin beneath the Pil´sk Suite would be expected, i.e., Cretaceous (Slavyan suite) or Miocene Tymsk suite. However, the Cretaceous sandstones are poorly sorted lithic arkoses and wackes, which weather to a strong green color, and the Tymsk suite consists almost exclusively of siliceous units, which closely resemble those of the Pil´sk Suite.

On this basis, the most likely source for the original stratigraphic position of the intruded sandstones are either an unexposed Paleogene suite overlying the Cretaceous-Tertiary unconformity, or an offshore, deeper water sandstone unit in the Pil´sk or Tymsk suites. In the absence of any petrographic data on the injected sands, we were unable to distinguish between these alternatives.

Structural Geology

The entire section exposed along the southeast coast of the Schmidt Peninsula is heavily folded and faulted (Figure 4), making correlation difficult. Our structural observations and measurements do, however, help to constrain the tectonic history of this region. The main points are listed below.

It is clear from the cross section (Figure 4) that the deformation clusters into several high-strain zones. Within each zone, the folds have a chevron geometry (Figure 14), with an incipient axial-planar fracture cleavage developed within the biosiliceous facies in some areas. There are parasitic folds on the limbs of the major folds; these have the expected sense of vergence. Within the hinge zones of many of the larger structures there are chaotic compensation folds with no consistent vergence direction (Figure 14A). Fold orientation is consistent both geographically, along the entire length of the coast, and at various scales; bedding in the Pil´sk Suite clusters along a northwest-southeast strike (Figure 15A). Because the intrusive sandstones are mostly parallel to bedding, this also describes the orientation of the intrusions.

Figure 14.

Deformation of the Pil’sk Suite. (A) Southwest-verging chevron anticline; person for scale. (B) Closely associated ductile and brittle deformation of siliceous units (facies P1-P4) and brown sandstones (facies P11). In this example, the brown sandstone unit has been folded and then cut by a small reverse fault, indicating that both emplacement and cementation of the intrusive sands occurred prior to deformation. If sand intrusion was triggered by the early stages of deformation, then the brittle behavior of the sand units suggests rapid postintrusion diagenesis. Person for scale.

Figure 14.

Deformation of the Pil’sk Suite. (A) Southwest-verging chevron anticline; person for scale. (B) Closely associated ductile and brittle deformation of siliceous units (facies P1-P4) and brown sandstones (facies P11). In this example, the brown sandstone unit has been folded and then cut by a small reverse fault, indicating that both emplacement and cementation of the intrusive sands occurred prior to deformation. If sand intrusion was triggered by the early stages of deformation, then the brittle behavior of the sand units suggests rapid postintrusion diagenesis. Person for scale.

Figure 15.

Structural data from the Pil’sk Suite. (A) Lower hemisphere stereographic projection of contoured poles to bedding, showing strong clustering on either side of northwest-southeast-trending fold axes. (B) Lower hemisphere stereographic projection of contoured poles to reverse faults. These indicate a northeast-southwest direction of compression, with a dominant transport direction toward the southwest. (C) Lower hemisphere stereographic projection of contoured poles to normal faults. These have similar strike to the reverse faults, but downthrow to the northeast.

Figure 15.

Structural data from the Pil’sk Suite. (A) Lower hemisphere stereographic projection of contoured poles to bedding, showing strong clustering on either side of northwest-southeast-trending fold axes. (B) Lower hemisphere stereographic projection of contoured poles to reverse faults. These indicate a northeast-southwest direction of compression, with a dominant transport direction toward the southwest. (C) Lower hemisphere stereographic projection of contoured poles to normal faults. These have similar strike to the reverse faults, but downthrow to the northeast.

Fold axes are either subvertical or dip steeply to the northeast, indicating a southwest vergence direction (see cleavage orientation in Figure 15A). Much of the ductile deformation is accommodated by layer- parallel slip, indicated by slickensides on bed boundaries (cf. Tanner, 1989).

Reverse faults exist in the succession with throws of several meters to tens of meters. These faults tend to be related to the steep or overturned limbs of folds. Smaller scale normal faults (throws less than 1 m [3.3 ft]) are also present, but their time relationship to the reverse faults is unknown. Reverse faulting in the Pil´sk Suite is compatible with a northeast-southwest compression direction (Figure 15B), whereas the predominance of northeast-dipping faults supports a southwest vergence and transport direction. Normal faults have the same strike as the reverse faults but downthrow exclusively to the northeast (Figure 15C).

The minimum mean shortening estimated from the coastal cross section (Figure 4), which runs approximately perpendicular to the structural grain, is 43%. Shortening varies along the section, with the maximum in the high-strain zones, which are spaced approximately 1 km (0.6 mi) apart. This probably represents a series of flower structures, related to strike-slip faults, probably rooted in the basement. Zones of abundant intrusive sands are coincident with the high-strain zones.

Discussion

Triggering Mechanism of Injection

Because Sakhalin sits astride a strike-slip plate boundary, which is an active earthquake zone, a tectonic triggering mechanism for intrusion seems most likely. The most convincing evidence for tectonic triggering of sand injection is the concentration of sandstone intrusions in the high-strain zones (Figure 4).

Timing of Events

Age of Injection

Timing of injection is difficult to constrain. As stated, the vast majority of intruded sands were observed in the Pil´sk Suite with minor sand dikes in Tymsk and Kaskad sediments (Table 1). The absence of intruded sandstones in the overlying succession suggests that intrusion occurred before deposition of the Mayamraf suite. However, if the hydrostatic pressure gradient was compatible with horizontal intrusion at Pil´sk level, there is no reason why the overlying succession should have been intruded even if it was already present. The most that can be said is that intrusion is post-Pil´sk and pre- or syndeformation.

Age of Deformation

Deformation of the Neogene succession on Schmidt Peninsula has previously been thought to be late Pliocene (Ratnovskiy, 1960), i.e., post-Mattituk suite (Table 1), but its timing is not well constrained. Our observations on the southeast coast show a decrease in deformational intensity between the Kaskad and the Mayamraf suites, indicating that deformation occurred after the deposition of the Kaskad suite (i.e., during the middle to late Miocene). Middle to late Miocene deformation may also account for the absence here of the Vengiriy suite (which is present on the west coast of the Schmidt Peninsula) and the unconformity between the Pil´sk and Mayamraf suites on the north coast of the Schmidt Peninsula (Figure 5).

Age of Diagenesis

The compaction patterns around some carbonate concretions suggest that early carbonate diagenesis affected the Pil´sk Suite (Figure 16); the intruded sandstones (facies P11) are also cemented by carbonate. Their sharp contacts with siliceous rocks suggest that silica diagenesis had already begun to indurate the sequence prior to intrusion. If sand intrusion was triggered by the onset of deformation, the brittle fracture of the intruded sandstones suggests rapid postintrusion lithification. In contrast, carbonate cementation in the white sand facies (P10) is negligible, and the muddy sandstone facies (P9) is also poorly cemented. This implies that the sand intrusions were a pathway for cementing carbonate-rich fluids.

Figure 16.

(A) Large carbonate concretions elongate along bedding; person for scale. (B) Spherical concretion with considerable deformation and truncation of the surrounding bedding; person for scale. In both cases, differential compaction around the concretion indicates early carbonate diagenesis.

Figure 16.

(A) Large carbonate concretions elongate along bedding; person for scale. (B) Spherical concretion with considerable deformation and truncation of the surrounding bedding; person for scale. In both cases, differential compaction around the concretion indicates early carbonate diagenesis.

The inferred sequence of deposition, deformation, intrusion, and diagenesis is summarized in Table 5.

Model for Formation

Model for Formation

The main uncertainty is the timing of sand intrusion with respect to deformation, with both being constrained into a relatively restricted period in the late Miocene (Tortonian, about 4 Ma). The most logical explanation is that the two processes were coeval. Figure 17 illustrates a conceptual model where an original sand layer is distributed evenly across the area. When strike-slip faulting begins, with the development of a positive flower structure, sand begins to be injected up the fault system (Figure 17B). As deformation progresses, sand is concentrated into the high-strain zones (Figure 17C). This may seem counterintuitive, but layer- parallel flexural slip creates spaces in fold hinges; these are areas of low pressure, commonly occupied by mineral deposits (Ramsay, 1974; Tanner, 1989). As deformation progresses, the sandstone intrusions were undergoing diagenesis and lithification, behaving in a brittle manner in response to the late-stage thrusts.

Figure 17.

Illustration of the development of a flower structure with associated sand injections and related deformation of the sediment surface. (A) Predeformation situation, with an original sand unit (yellow) encased in diatomite (blue). (B) Initiation of a strike-slip fault with associated positive flower; the seal of the sand bed is breached, and sand starts to flow into the fault system. (C) Concentration of sand to areas of chevron folding, depletion of original unit, and warping of sediment surface by differential withdrawal, compaction, and unrecoverable strain.

Figure 17.

Illustration of the development of a flower structure with associated sand injections and related deformation of the sediment surface. (A) Predeformation situation, with an original sand unit (yellow) encased in diatomite (blue). (B) Initiation of a strike-slip fault with associated positive flower; the seal of the sand bed is breached, and sand starts to flow into the fault system. (C) Concentration of sand to areas of chevron folding, depletion of original unit, and warping of sediment surface by differential withdrawal, compaction, and unrecoverable strain.

Summary of the sedimentation and deformation history of the southeast part of the Schmidt Peninsula.*

Table 5.
Summary of the sedimentation and deformation history of the southeast part of the Schmidt Peninsula.*
TimeEvent
CretaceousSandy fluvial deposition, sourced from the north
Late Cretaceous -late OligoceneDeformation resulting in K-T unconformity and creation of mineral veins in the Cretaceous succession
Early-middle MioceneDeposition of siliceous-rich sequence with periodic and increasing influxes of sand from the west
Nucleation and growth of carbonate concretions
Late middle -late MioceneStart of deformation: chevron folding and sand(?) intrusion
Rapid cementation of sand intrusions
Progressive deformation: thrust and brittle deformation of sand intrusions. Later extension; normal faults may be related to formation of the Derugin Basin
Latest MioceneSlow clastic sedimentation resulting in the accumulation of sandy opoka
PlioceneSouthward progradation of a lobe of the Amur delta
Late PlioceneUplift
TimeEvent
CretaceousSandy fluvial deposition, sourced from the north
Late Cretaceous -late OligoceneDeformation resulting in K-T unconformity and creation of mineral veins in the Cretaceous succession
Early-middle MioceneDeposition of siliceous-rich sequence with periodic and increasing influxes of sand from the west
Nucleation and growth of carbonate concretions
Late middle -late MioceneStart of deformation: chevron folding and sand(?) intrusion
Rapid cementation of sand intrusions
Progressive deformation: thrust and brittle deformation of sand intrusions. Later extension; normal faults may be related to formation of the Derugin Basin
Latest MioceneSlow clastic sedimentation resulting in the accumulation of sandy opoka
PlioceneSouthward progradation of a lobe of the Amur delta
Late PlioceneUplift

*Events relating to sand intrusion and diagenesis are highlighted.

This model also suggests that positive topography would be created on the contemporaneous sediment surface above the flower structures. The association of high ground with flower structures is well known, the classic example being the Newport-Inglewood fault zone in the Los Angeles basin (Wright, 1991). The creation of this topography is commonly associated with unrecoverable strain, and there is strong evidence that it is a stepped process associated with earthquakes (Sandwell et al., 2002). It is, however, possible that this process could be enhanced by injection, via differential sand withdrawal from areas between faults and differential compaction between the sand in the fault zone and the surrounding diatomites.

Comparison with California

An obvious comparison can made with California: both areas are located on a dextral strike-slip plate boundary, with abundant sandstone injections into middle Miocene diatomite facies. The best exposed and best known sand intrusions in California are on the coast near Santa Cruz (Thompson et al., 2007). However, the scale and geometry of these are very different, with bodies hundreds of meters across, cutting vertically through the host sediment. Some sills are associated with these large pipes (see Thompson et al., 2007, figure 12), but they are an order of magnitude bigger than anything seen on Sakhalin. In the San Joaquin Valley, T. H. Nilsen (1998, personal communication) has demonstrated that turbidites of the Stevens sandstone (interbedded with the middle Miocene Monterey Formation) contain significant bedding-parallel intrusions, suggesting that some of the complicated correlation illustrated by Webb (1981) might be caused by injected sands. The San Joaquin examples are closer in scale to those on Sakhalin, although they are not involved in significant deformation.

Criteria for Recognizing Sand Sills

The exceptional exposure of these intruded sand units allowed us to draw up a set of criteria that can be used to identify bedding-parallel intruded sands in the subsurface. These criteria are listed below, and their possible subsurface value is discussed.

  • 1)

    Abrupt changes of stratigraphic position is the most important observation in outcrop but would only be seen on seismic sections if the relief of the step was large enough and the intrusion was thick enough.

  • 2)

    Erosive tops to sandstone units are important in the outcrop recognition of sandstone sills. This feature might be recognized in core if the well intersected a step in the boundary.

  • 3)

    Abrupt thickness changes and terminations are diagnostic in outcrop but would not be apparent in core. If the changes were to be at a large enough scale, they would be seen on seismic sections.

  • 4)

    Putting criteria 1 –3 together, there is a tendency for the sand sills to form anastomosing complexes, with subordinate linking sand dikes. Like most of the other features, this is readily apparent in outcrop and would not be seen in core but could be visible on seismic sections where the scale of the complexes was large enough. The anastomosing geometry and the tendency for both individual intrusions and groups of intrusions to change strati- graphic level means that these intruded sands are difficult to correlate laterally across more than 10 m (33 ft). This is also a problem in the subsurface.

  • 5)

    The lack of any current-generated structures in core or image logs should indicate the absence of a sediment surface (Raudkivi, 1967) and may suggest injection (i.e., pipe flow).

  • 6)

    Other internal features of the bed, such as normal- inverse grading of the coarse tail (xenoliths) and lack of grading in the sand fraction, could be seen in core. The presence of tool marks is not diagnostic of turbidites, but with injected sands, there is a possibility of creating tool marks on the unit top.

  • 7)

    In the case of Sakhalin, where the intrusions are into biosiliceous facies, the lack of fine clastic facies argues against a turbidite origin. This lack of mud and silt-grade material also leads to the creation of mirror stratigraphy on either side of sandstone layers. This is not absolutely diagnostic, but the absence of separate hemipelagic and turbidite mud facies might be detectable in core.

Conclusions

We have described the geology of the southeast Schmidt Peninsula, which comprises a thin Neogene succession overlying a Mesozoic outer arc high. The bulk of the Neogene succession is composed of bio- siliceous material. Within the middle Miocene Pil´sk Suite, brown sandstone units represent sand injections, derived from an unknown depositional source unit. The bulk of these intrusive features are sills, and they are concentrated into high-strain zones in a possible flower structure.

Deformation of the middle Miocene succession, intrusion of the sandstone sills, and their subsequent lithi- fication seem to have proceeded very fast, with cementation of the sandstones predating the last phase of deformation. Because these intrusions occurred at shallow burial depths (probably about 500 m [1640 ft]), we hypothesize that there ought to have been deformation of the surface caused by differential sand withdrawal and subsequent compaction.

Obvious limitations to this study exist. First, only a single, two-dimensional outcrop (albeit well exposed) is present. Second, we have no knowledge of any feeder system for these sandstone sills or of the parent sand tank. Third, we cannot say whether these sand injections linked through to the contemporaneous surface. However, the occurrence is unusual and adds to the knowledge of the wide range of possible forms of sand injections.

References Cited

Davies
,
C.
Poynter
,
S. E.
Macdonald
,
D. I. M.
Flecker
,
R.
Voronova
,
L. G.
Galverson
,
V. G.
Kovtunovich
,
P. Y.
Fot’yanova
,
L. I.
Blanc
,
E.
,
2005
,
Facies analysis of the Neogene delta of the Amur River, Sakhalin, Russian Far East: Controls on sand distribution
, in
Giosan
,
L.
Bhattacharya
,
J. P.
eds.,
River deltas— Concepts, models and examples: SEPM Special Publication
83
, p.
207
229
.
Fournier
,
M.
Jolivet
,
L.
Huchon
,
P.
Sergeyev
,
K. F.
Oscorbin
,
L. S.
,
1994
,
Neogene strike-slip faulting in Sakhalin and the Japan Sea opening: Journal of Geophysical Research
, v.
99
, p.
2701
2725
.
Ivaschenko
,
A. I.
Kim
,
C. U.
Oscorbin
,
L. S.
Poplavskaya
,
L. N.
Poplavskiy
,
A. A.
Burymskaya
,
R. N.
Mikhailova
,
T. G.
Vasilenko
,
N. F.
Streltsov
,
M. I.
,
1997
, The Nefte-gorsk, Sakhalin Island, earthquake of 27 May 1995: The Island Arc, v.
6
, p.
288
307
.
Jolly
,
R. J. H.
Lonergan
,
L.
,
2002
,
Mechanisms and controls on the formation of sand intrusions: Journal ofthe Geological Society (London)
, v.
159
, p.
605
617
.
Lowe
,
D. R.
,
1982
,
Depositional models with special reference to the deposits of high density turbidity currents: Journal of Sedimentary Petrology
, v.
52
, p.
279
297
.
Newsom
,
J. F.
,
1903
,
Clastic dikes: Geological Society of America Bulletin
, v.
14
, p.
227
268
.
Ramsay
,
J. G.
,
1974
,
Development of chevron folds: Geological Society of America Bulletin
, v.
85
, p.
1741
1754
.
Ratnovskiy
,
i.
,
1960
,
Geologicul structure of the Schmidt Peninsula, Sakhalin: Leningrad, NeUiu
,
104
p.
Raudkivi
,
A. J.
,
1967
,
Loose boundary hydraulics: Oxford, Peigamon Press
,
331
p.
Sandwell
,
D. T.
Sichoix
,
L.
Smith
,
B.
,
2002
,
The 1999 Hector mine earthquake, southern California: Vector near-field displacements from ERS inSAR: Seismolog-ical Society of America Bulletin
, v.
92
, p.
1341
1354
.
Seno
,
T.
Sakurai
,
T.
Stein
,
S.
,
1996
,
Can the Okhotsk plate be distinguished from the North American plate?: Journal of Geophysical Research— Solid Earth
, v.
101
, no. B5, p.
11,305
11,315
.
Stow
,
D. A. V.
,
1985
,
Fine-grained sediments in deep water— An overview of processes and facies models: Geo-Marine Letters
, v.
5
, p.
17
23
.
Tanner
,
P. W. G.
,
1989
,
The flexural-slip mechanism: Journal of Structural Geology
, v.
11
, p.
635
655
.
Taylor
,
B. J.
,
1982
,
Sedimentary dikes, pipes and related structures in the Mesozoic sediments of south-eastern Alexander island: British Antarctic Survey Bulletin
, v.
51
, p.
1
42
.
Thompson
,
B. J.
Garrison
,
R. E.
Moore
,
J. C.
,
2007
,
A reservoir-scale Miocene injectite near Santa Cruz, California
, in
Hurst
,
A.
Cartwright
,
J.
eds., Sand injectites: implications for hydrocarbon exploration and production: AAPG Memoir 87, p.
151
162
.
Vereshchagin
,
V. H.
, et al.,
1969
,
Geologecheskaya karta Sakhalina [Geological map of Sakhalin].
Ministry of Geology of the USSR, scale 1:1,000,000, 1 sheet.
Weaver
,
R.
Roberts
,
A. M.
Flecker
,
R.
Macdonald
,
D. i. M.
,
2004
,
Tertiary geodynamics of Sakhalin (NW Pacific) from anisotropy of magnetic susceptibility fabrics and paleomagnetic data: Tectonophysics
, v.
379
, p.
25
42
.
Webb
,
G. W.
,
1981
,
Stevens and earlier Miocene turbidite sandstones, southern San Joaquin Valley, California: AAPG Bulletin
, v.
65
, p.
438
465
.
Wright
,
T. L.
,
1991
,
Structural geology and tectonic evolution of the Los Angeles basin, California: AAPG Memoir 52
, p.
35
134
.
Zonenshain
,
L. P.
Kuz’min
,
M. i.
Natapov
,
L. V.
,
1990
,
Geology of the USSR: A plate-tectonic synthesis: Washington, D.C., AGU Geodynamics Series 21
,
242
p.

Acknowledgments

Fieldwork on Sakhalin was conducted as part of the Cambridge Arctic Shelf Programme (CASP) Research Program funded by Agip, Anadarko, Arco, BP, Exxon, the Japan National Oil Corporation, Mobil, Philips, and Texaco. Work was in collaboration with Sakhalin Geological Research Expedition (SGRE), Yuzhno-Sakhalinsk; logistic support was provided by SGRE. The scientific party comprised Christine Brouet-Menzies (translator, CASP), Richard Weaver (paleomagnetist, University of Southampton), Vladimir Galversen (geologist, SGRE), Pavel Kovtunovich (geologist, SGRE), Boris Salnikov (director, Sakhalinnipimorneft, Okha). We are grateful to all our colleagues for their stimulating discussions. We also thank Zhenia Rasshchepkina and Valeriy Gorbachov for their support in the field. We are also indebted to late Yuri Kovtunovich, then chief geologist of SGRE, for his support and friendship. We are grateful to Matt Brettle, Andrew Hurst, and Olivier Parize for their thorough reviews of the manuscript.

Figures & Tables

Figure 1.

Geology and setting of Sakhalin. (A) The area around the Sea of Okhotsk showing the relationship of the central Sakhalin Fault system to Hokkaido and the active Japan-Kuril subduction zone. (B) Geology of Sakhalin (adapted from Vereshchagin et al., 1969) showing the extent of Neogene deposits. The arrow shows the location of the detailed map of the southeast Schmidt Peninsula section (Figure 2).

Figure 1.

Geology and setting of Sakhalin. (A) The area around the Sea of Okhotsk showing the relationship of the central Sakhalin Fault system to Hokkaido and the active Japan-Kuril subduction zone. (B) Geology of Sakhalin (adapted from Vereshchagin et al., 1969) showing the extent of Neogene deposits. The arrow shows the location of the detailed map of the southeast Schmidt Peninsula section (Figure 2).

Figure 2.

Detailed map of the southeast Schmidt Peninsula section (see inset for location). Exposure is near continuous from Mys Poklonnaya to the mouth of the Bolshoi Langri at Zim. Farther to the northeast from here, a security zone was not visited. Inset shows the positions of the north (N), west (W), and southeast (SE) Schmidt sections (see Figure 4). The camp is the location of the start of the mapped section (survey station T).

Figure 2.

Detailed map of the southeast Schmidt Peninsula section (see inset for location). Exposure is near continuous from Mys Poklonnaya to the mouth of the Bolshoi Langri at Zim. Farther to the northeast from here, a security zone was not visited. Inset shows the positions of the north (N), west (W), and southeast (SE) Schmidt sections (see Figure 4). The camp is the location of the start of the mapped section (survey station T).

Figure 3.

View north along the southeast coast of Schmidt Peninsula from Survey Station M. Note the dark (graygreen) Cretaceous sandstones in the foreground with the pale cliffs of the siliceous Pil’sk Suite behind; the higher cliffs in the middle ground reach 100 m (330 ft) above sea level. At the far end of the section, the darker, northwest-southeast-trending ridge formed of Mesozoic igneous rocks can just be seen, approximately 8 km (5 mi) away.

Figure 3.

View north along the southeast coast of Schmidt Peninsula from Survey Station M. Note the dark (graygreen) Cretaceous sandstones in the foreground with the pale cliffs of the siliceous Pil’sk Suite behind; the higher cliffs in the middle ground reach 100 m (330 ft) above sea level. At the far end of the section, the darker, northwest-southeast-trending ridge formed of Mesozoic igneous rocks can just be seen, approximately 8 km (5 mi) away.

Figure 4.

Cross sections of the exposure of the Pil’sk Suite on the southeast coast of the Schmidt Peninsula. For location of the section line, see Figure 2; note that survey station letters on the section correspond to those on the map.

Figure 4.

Cross sections of the exposure of the Pil’sk Suite on the southeast coast of the Schmidt Peninsula. For location of the section line, see Figure 2; note that survey station letters on the section correspond to those on the map.

Figure 5.

Stratigraphic columns for the Schmidt Peninsula area (for locations, see Figure 2, inset) based on Cambridge Arctic Shelf Programme (CASP) fieldwork; a review of Russian stratigraphic literature by L. G. Voronova and J. L.Wardell (1991, personal communication); and from B. A. Salnikov (1998, personal communication). The suites are Kak = Kaskad; Mac = Machigar; Mat = Mattituk; May = Mayamraf; Plk = Pil’sk; Pom = Pomyr; Tym = Tymsk; Ven = Vengiriy.

Figure 5.

Stratigraphic columns for the Schmidt Peninsula area (for locations, see Figure 2, inset) based on Cambridge Arctic Shelf Programme (CASP) fieldwork; a review of Russian stratigraphic literature by L. G. Voronova and J. L.Wardell (1991, personal communication); and from B. A. Salnikov (1998, personal communication). The suites are Kak = Kaskad; Mac = Machigar; Mat = Mattituk; May = Mayamraf; Plk = Pil’sk; Pom = Pomyr; Tym = Tymsk; Ven = Vengiriy.

Figure 6.

(A) Block from the basal part of a brown sand unit containing angular clasts of siliceous sediment; pencil for scale. (B) The top of a brown sandstone unit (inverted in the steep limb of a fold) containing similar angular siliceous clasts (arrowed); hammer for scale.

Figure 6.

(A) Block from the basal part of a brown sand unit containing angular clasts of siliceous sediment; pencil for scale. (B) The top of a brown sandstone unit (inverted in the steep limb of a fold) containing similar angular siliceous clasts (arrowed); hammer for scale.

Figure 7.

Grooves on the base of a brown sandstone unit; pencil for scale.

Figure 7.

Grooves on the base of a brown sandstone unit; pencil for scale.

Figure 8.

Photograph and interpretive sketch of an injected sand unit that changes direction in a series of 90° bends before terminating abruptly; injected sands are shown in yellow; scale is indicated on sketch.

Figure 8.

Photograph and interpretive sketch of an injected sand unit that changes direction in a series of 90° bends before terminating abruptly; injected sands are shown in yellow; scale is indicated on sketch.

Figure 9.

Erosive top of a sandstone unit; pencil for scale.

Figure 9.

Erosive top of a sandstone unit; pencil for scale.

Figure 10.

Brown sandstone unit changing from a dike to an anastomosing sill, with associated deformation along its edges; scale on photograph. The line drawing shows intrusive sand units (brown) in host siliceous sediments (gray); note that many small sand intrusions (centimeter scale) have been left off this drawing.

Figure 10.

Brown sandstone unit changing from a dike to an anastomosing sill, with associated deformation along its edges; scale on photograph. The line drawing shows intrusive sand units (brown) in host siliceous sediments (gray); note that many small sand intrusions (centimeter scale) have been left off this drawing.

Figure 11.

Abrupt termination of intrusive sandstone units; figure for scale.

Figure 11.

Abrupt termination of intrusive sandstone units; figure for scale.

Figure 12.

Injected sand sheet cutting obliquely through biosiliceous rocks of association PA (see Table 4 in text); figure for scale.

Figure 12.

Injected sand sheet cutting obliquely through biosiliceous rocks of association PA (see Table 4 in text); figure for scale.

Figure 13.

Correlation of measured sections on either side of the anticline at locality (DM.151/2). Note that although both siliceous and white sandstone units can be traced, correlation of individual beds is obscured by prolific intrusive sandstones. The difference in stratigraphic thickness between the sections is approximately the same as the change in thickness of the intrusive sandstones. The numbers by each log refer to the total number of individual sand intrusions in each unit.

Figure 13.

Correlation of measured sections on either side of the anticline at locality (DM.151/2). Note that although both siliceous and white sandstone units can be traced, correlation of individual beds is obscured by prolific intrusive sandstones. The difference in stratigraphic thickness between the sections is approximately the same as the change in thickness of the intrusive sandstones. The numbers by each log refer to the total number of individual sand intrusions in each unit.

Figure 14.

Deformation of the Pil’sk Suite. (A) Southwest-verging chevron anticline; person for scale. (B) Closely associated ductile and brittle deformation of siliceous units (facies P1-P4) and brown sandstones (facies P11). In this example, the brown sandstone unit has been folded and then cut by a small reverse fault, indicating that both emplacement and cementation of the intrusive sands occurred prior to deformation. If sand intrusion was triggered by the early stages of deformation, then the brittle behavior of the sand units suggests rapid postintrusion diagenesis. Person for scale.

Figure 14.

Deformation of the Pil’sk Suite. (A) Southwest-verging chevron anticline; person for scale. (B) Closely associated ductile and brittle deformation of siliceous units (facies P1-P4) and brown sandstones (facies P11). In this example, the brown sandstone unit has been folded and then cut by a small reverse fault, indicating that both emplacement and cementation of the intrusive sands occurred prior to deformation. If sand intrusion was triggered by the early stages of deformation, then the brittle behavior of the sand units suggests rapid postintrusion diagenesis. Person for scale.

Figure 15.

Structural data from the Pil’sk Suite. (A) Lower hemisphere stereographic projection of contoured poles to bedding, showing strong clustering on either side of northwest-southeast-trending fold axes. (B) Lower hemisphere stereographic projection of contoured poles to reverse faults. These indicate a northeast-southwest direction of compression, with a dominant transport direction toward the southwest. (C) Lower hemisphere stereographic projection of contoured poles to normal faults. These have similar strike to the reverse faults, but downthrow to the northeast.

Figure 15.

Structural data from the Pil’sk Suite. (A) Lower hemisphere stereographic projection of contoured poles to bedding, showing strong clustering on either side of northwest-southeast-trending fold axes. (B) Lower hemisphere stereographic projection of contoured poles to reverse faults. These indicate a northeast-southwest direction of compression, with a dominant transport direction toward the southwest. (C) Lower hemisphere stereographic projection of contoured poles to normal faults. These have similar strike to the reverse faults, but downthrow to the northeast.

Figure 16.

(A) Large carbonate concretions elongate along bedding; person for scale. (B) Spherical concretion with considerable deformation and truncation of the surrounding bedding; person for scale. In both cases, differential compaction around the concretion indicates early carbonate diagenesis.

Figure 16.

(A) Large carbonate concretions elongate along bedding; person for scale. (B) Spherical concretion with considerable deformation and truncation of the surrounding bedding; person for scale. In both cases, differential compaction around the concretion indicates early carbonate diagenesis.

Figure 17.

Illustration of the development of a flower structure with associated sand injections and related deformation of the sediment surface. (A) Predeformation situation, with an original sand unit (yellow) encased in diatomite (blue). (B) Initiation of a strike-slip fault with associated positive flower; the seal of the sand bed is breached, and sand starts to flow into the fault system. (C) Concentration of sand to areas of chevron folding, depletion of original unit, and warping of sediment surface by differential withdrawal, compaction, and unrecoverable strain.

Figure 17.

Illustration of the development of a flower structure with associated sand injections and related deformation of the sediment surface. (A) Predeformation situation, with an original sand unit (yellow) encased in diatomite (blue). (B) Initiation of a strike-slip fault with associated positive flower; the seal of the sand bed is breached, and sand starts to flow into the fault system. (C) Concentration of sand to areas of chevron folding, depletion of original unit, and warping of sediment surface by differential withdrawal, compaction, and unrecoverable strain.

Stratigraphic names of suites in the Southeast part of the Schmidt Peninsula.*

Table 1.
Stratigraphic names of suites in the Southeast part of the Schmidt Peninsula.*
StageSubstageSuiteThicknessInjected Sands
Pliocene(Undefined)Mattituk<50 mNone
MioceneTortonian - MessinianMayamraf´<50 mNone
Early-middle TortonianLocal unconformity in southeast Schmidt
SerravallianKaskad>200 mSome thin sheets
Langhian - Serravallian(?)Pil´sk>500 mAbundant
Aquitanian-BurdigalianTymsk>150 mSome thin sheets
PaleogeneWidespread unconformity on Schmidt Peninsula
CretaceousMaastrichtian(?)Slavyan>175 mNone
StageSubstageSuiteThicknessInjected Sands
Pliocene(Undefined)Mattituk<50 mNone
MioceneTortonian - MessinianMayamraf´<50 mNone
Early-middle TortonianLocal unconformity in southeast Schmidt
SerravallianKaskad>200 mSome thin sheets
Langhian - Serravallian(?)Pil´sk>500 mAbundant
Aquitanian-BurdigalianTymsk>150 mSome thin sheets
PaleogeneWidespread unconformity on Schmidt Peninsula
CretaceousMaastrichtian(?)Slavyan>175 mNone

*The Pil´sk Suite, where most of the injected sand structures occur, is highlighted. Note that the basic Russian lithostratigraphic unit is the cBuma (Svita or Suite). This is “formation,” but the concepts are different because the suite contains an implication that the unit has a particular age range. To emphasize this difference, we have used the word “suite” throughout when referring to stratigraphic units. For clarity, we have omitted the feminine adjectival ending (-cKaЯl [-Skaya]), which is a formal part of every suite name.

Sedimentary facies of the middle Miocene Pil´sk Suite, southeast Schmidt Peninsula.*

Table 2.
Sedimentary facies of the middle Miocene Pil´sk Suite, southeast Schmidt Peninsula.*
No.NameThickness (m)DescriptionInterpretation
P1Opoka0.15–1.0Pale weathering, brown when fresh; hydrocarbon smell; irregular and undulating top and bottom boundaries; micrometer- to millimeter-scale lamination; may contain fish scales and benthic and planktonic forams;can be bioturbated.Background biosiliceous sedimentation.
P2Porcellanite0.01–0.2Weathers medium gray, dark gray when fresh; strong hydrocarbon smell; laminated with a moderate to well-developed fissility; can be very finely laminated, can be foram bearing; can have stylolites; can be bioturbated.Biosiliceous sedimentation, with higher grade diagenesis than P1.
P3Chert0.01–0.1Uncommon facies;dark brown-black, commonly red weathering; nodular or banded discontinuous layers; can be associated with glauconite.Biosiliceous sedimentation, with higher grade diagenesis than P2.
P4Siliceous clay-mud0.03–0.5Very dark brown, sapropelic(?);varying siliceous content;slight to strong hydrocarbon smell; uncommonly laminated; can be bioturbated; no forams observed.High productivity, low oxygen levels, suspension sedimentation.
P5Sandy opoka0.1–1.5Uncommon facies; laminated opoka, with floating sand grains (generally vfs grade).Bioturbation, slump mixing, or mixing; from fluvial plume;low clastic input.
P6Glauconitic opoka0.1 –0.25Uncommon facies; low concentrations of dispersed glauconite as floating grains in blocky opoka or within forams.Mixing, as P5, but with lower clastic sedimentation rate.
P7Tuff0.005–0.1Blue-gray; sticky; can contain grains up to sand grade, some of which may be crystals.Diagenetically altered airfall crystal tuff.
P8Mudstone0.005–0.25Gray; may contain organic matter; can be contorted; impersistent or can pass laterally into a layer of clasts (commonly very irregular).Suspension deposition.
P9Muddy sandstone22.0Chaotic with detached sand balls.Submarine slide deposits.
P10White sandstone0.25–2.5Poorly consolidated; erosive based; internal scours; cross-bedded; abundant clay clasts; parallel laminated in places; can be amalgamated; moderately sorted; uncommon load-cast base.Current deposition in delta progradation events (Amur sands).
11Brown sandstone0.02–3.0Brown weathering; very well cemented; well sorted, predominantly fine sand, subsidiary medium-coarse; carbonate cement (white); erosive base and top; sandstones generally ungraded, but coarse tail (both normal and inverse) present; grading generally only in thicker beds; grooves on base of some beds; dikes and sills and other intrusive structures observed.Subvertical and subhorizontal sand intrusion.
P12Glauconitic sandstone0.1 –0.75Associated with phosphate, either as a bed or as nodules; patchy distribution; where associated with clastics, it is bioturbated fine- medium sandstone with glauconite in burrows; uncommon glauconite in sandy laminated porcellanite.Either slow sedimentation in wave-worked environment, or reworked downslope by possible debris flow.
P13Concretions0.02–1.0Spherical to elongate bedding-parallel concretions; CaCO3(?) or other carbonate; undulating top and bottom; small irregular-elongate concretions associated with tuff; spherical concretions associated with siliceous units; uncommon association with intrusive sandstones, but never cut by them; weatherlike sandstone; brecciated texture in some; some have calcite veins.Relatively early (precompaction) diagenesis.
No.NameThickness (m)DescriptionInterpretation
P1Opoka0.15–1.0Pale weathering, brown when fresh; hydrocarbon smell; irregular and undulating top and bottom boundaries; micrometer- to millimeter-scale lamination; may contain fish scales and benthic and planktonic forams;can be bioturbated.Background biosiliceous sedimentation.
P2Porcellanite0.01–0.2Weathers medium gray, dark gray when fresh; strong hydrocarbon smell; laminated with a moderate to well-developed fissility; can be very finely laminated, can be foram bearing; can have stylolites; can be bioturbated.Biosiliceous sedimentation, with higher grade diagenesis than P1.
P3Chert0.01–0.1Uncommon facies;dark brown-black, commonly red weathering; nodular or banded discontinuous layers; can be associated with glauconite.Biosiliceous sedimentation, with higher grade diagenesis than P2.
P4Siliceous clay-mud0.03–0.5Very dark brown, sapropelic(?);varying siliceous content;slight to strong hydrocarbon smell; uncommonly laminated; can be bioturbated; no forams observed.High productivity, low oxygen levels, suspension sedimentation.
P5Sandy opoka0.1–1.5Uncommon facies; laminated opoka, with floating sand grains (generally vfs grade).Bioturbation, slump mixing, or mixing; from fluvial plume;low clastic input.
P6Glauconitic opoka0.1 –0.25Uncommon facies; low concentrations of dispersed glauconite as floating grains in blocky opoka or within forams.Mixing, as P5, but with lower clastic sedimentation rate.
P7Tuff0.005–0.1Blue-gray; sticky; can contain grains up to sand grade, some of which may be crystals.Diagenetically altered airfall crystal tuff.
P8Mudstone0.005–0.25Gray; may contain organic matter; can be contorted; impersistent or can pass laterally into a layer of clasts (commonly very irregular).Suspension deposition.
P9Muddy sandstone22.0Chaotic with detached sand balls.Submarine slide deposits.
P10White sandstone0.25–2.5Poorly consolidated; erosive based; internal scours; cross-bedded; abundant clay clasts; parallel laminated in places; can be amalgamated; moderately sorted; uncommon load-cast base.Current deposition in delta progradation events (Amur sands).
11Brown sandstone0.02–3.0Brown weathering; very well cemented; well sorted, predominantly fine sand, subsidiary medium-coarse; carbonate cement (white); erosive base and top; sandstones generally ungraded, but coarse tail (both normal and inverse) present; grading generally only in thicker beds; grooves on base of some beds; dikes and sills and other intrusive structures observed.Subvertical and subhorizontal sand intrusion.
P12Glauconitic sandstone0.1 –0.75Associated with phosphate, either as a bed or as nodules; patchy distribution; where associated with clastics, it is bioturbated fine- medium sandstone with glauconite in burrows; uncommon glauconite in sandy laminated porcellanite.Either slow sedimentation in wave-worked environment, or reworked downslope by possible debris flow.
P13Concretions0.02–1.0Spherical to elongate bedding-parallel concretions; CaCO3(?) or other carbonate; undulating top and bottom; small irregular-elongate concretions associated with tuff; spherical concretions associated with siliceous units; uncommon association with intrusive sandstones, but never cut by them; weatherlike sandstone; brecciated texture in some; some have calcite veins.Relatively early (precompaction) diagenesis.

*Facies P11 (injected sands) is highlighted.

Main features of the four sandstone facies in the Pil´sk Suite in the southeast part of the Schmidt Peninsula.

Table 3.
Main features of the four sandstone facies in the Pil´sk Suite in the southeast part of the Schmidt Peninsula.
Type of StructureWhite Sand (Facies P10)Glauconitic Sandstone (Facies P12)Muddy Sandstone (Facies P9)Brown Sandstone (Facies P11)
Current structuresParallel and cross-lamination,cross-beddingUncommon parallel laminationSynsedimentary slump nosesPoorly developed parallel lamination, tool marks (which can be on top of the unit)
Erosional structuresInternal scours and erosive basesNone seenNone seenErosive bases and tops, rip-up clasts at top and bottom of layers
GradingSmall-scale normal gradingNone seenNone seenNormal-inverse coarse-tail grading
Biogenic contentOrganic detritusBioturbatedNone seenNone seen
CementationUnlithifiedWell lithifiedPoorly lithifiedTight
InterpretationIn-situ deposits of marine currentsIn-situ deposits of marine currentsPostdeposition sediment sliding of marine depositsPostdepositional sand intrusion
Type of StructureWhite Sand (Facies P10)Glauconitic Sandstone (Facies P12)Muddy Sandstone (Facies P9)Brown Sandstone (Facies P11)
Current structuresParallel and cross-lamination,cross-beddingUncommon parallel laminationSynsedimentary slump nosesPoorly developed parallel lamination, tool marks (which can be on top of the unit)
Erosional structuresInternal scours and erosive basesNone seenNone seenErosive bases and tops, rip-up clasts at top and bottom of layers
GradingSmall-scale normal gradingNone seenNone seenNormal-inverse coarse-tail grading
Biogenic contentOrganic detritusBioturbatedNone seenNone seen
CementationUnlithifiedWell lithifiedPoorly lithifiedTight
InterpretationIn-situ deposits of marine currentsIn-situ deposits of marine currentsPostdeposition sediment sliding of marine depositsPostdepositional sand intrusion

Depositional facies associations of the middle Miocene Pil´sk Suite, southeast Schmidt Peninsula.*

Table 4.
Depositional facies associations of the middle Miocene Pil´sk Suite, southeast Schmidt Peninsula.*
AssociationsFaciesInterpretationEstimated Volume (%)
PAP1, P2 and P4 ±P13, ±P7, (±P3), (±P5),(±P6),l±P1lBackground biogenic sedimentation75
PBPH. P1, P2 and P4 (±P5), (±P13)Intrusive sand complexes in siliceous country rock15
PCP8, P9 and P10 l±P11lDelta progradation and gravity slides8
PDP12, P1, P2 and P3Authigenic glauconite formation in conditions of slow sedimentation2
AssociationsFaciesInterpretationEstimated Volume (%)
PAP1, P2 and P4 ±P13, ±P7, (±P3), (±P5),(±P6),l±P1lBackground biogenic sedimentation75
PBPH. P1, P2 and P4 (±P5), (±P13)Intrusive sand complexes in siliceous country rock15
PCP8, P9 and P10 l±P11lDelta progradation and gravity slides8
PDP12, P1, P2 and P3Authigenic glauconite formation in conditions of slow sedimentation2

*Intrusive sand facies association (PB) is highlighted. The volume estimates are for the whole suite as exposed on the Southeast Schmidt Peninsula section.

Summary of the sedimentation and deformation history of the southeast part of the Schmidt Peninsula.*

Table 5.
Summary of the sedimentation and deformation history of the southeast part of the Schmidt Peninsula.*
TimeEvent
CretaceousSandy fluvial deposition, sourced from the north
Late Cretaceous -late OligoceneDeformation resulting in K-T unconformity and creation of mineral veins in the Cretaceous succession
Early-middle MioceneDeposition of siliceous-rich sequence with periodic and increasing influxes of sand from the west
Nucleation and growth of carbonate concretions
Late middle -late MioceneStart of deformation: chevron folding and sand(?) intrusion
Rapid cementation of sand intrusions
Progressive deformation: thrust and brittle deformation of sand intrusions. Later extension; normal faults may be related to formation of the Derugin Basin
Latest MioceneSlow clastic sedimentation resulting in the accumulation of sandy opoka
PlioceneSouthward progradation of a lobe of the Amur delta
Late PlioceneUplift
TimeEvent
CretaceousSandy fluvial deposition, sourced from the north
Late Cretaceous -late OligoceneDeformation resulting in K-T unconformity and creation of mineral veins in the Cretaceous succession
Early-middle MioceneDeposition of siliceous-rich sequence with periodic and increasing influxes of sand from the west
Nucleation and growth of carbonate concretions
Late middle -late MioceneStart of deformation: chevron folding and sand(?) intrusion
Rapid cementation of sand intrusions
Progressive deformation: thrust and brittle deformation of sand intrusions. Later extension; normal faults may be related to formation of the Derugin Basin
Latest MioceneSlow clastic sedimentation resulting in the accumulation of sandy opoka
PlioceneSouthward progradation of a lobe of the Amur delta
Late PlioceneUplift

*Events relating to sand intrusion and diagenesis are highlighted.

Contents

GeoRef

References

References Cited

Davies
,
C.
Poynter
,
S. E.
Macdonald
,
D. I. M.
Flecker
,
R.
Voronova
,
L. G.
Galverson
,
V. G.
Kovtunovich
,
P. Y.
Fot’yanova
,
L. I.
Blanc
,
E.
,
2005
,
Facies analysis of the Neogene delta of the Amur River, Sakhalin, Russian Far East: Controls on sand distribution
, in
Giosan
,
L.
Bhattacharya
,
J. P.
eds.,
River deltas— Concepts, models and examples: SEPM Special Publication
83
, p.
207
229
.
Fournier
,
M.
Jolivet
,
L.
Huchon
,
P.
Sergeyev
,
K. F.
Oscorbin
,
L. S.
,
1994
,
Neogene strike-slip faulting in Sakhalin and the Japan Sea opening: Journal of Geophysical Research
, v.
99
, p.
2701
2725
.
Ivaschenko
,
A. I.
Kim
,
C. U.
Oscorbin
,
L. S.
Poplavskaya
,
L. N.
Poplavskiy
,
A. A.
Burymskaya
,
R. N.
Mikhailova
,
T. G.
Vasilenko
,
N. F.
Streltsov
,
M. I.
,
1997
, The Nefte-gorsk, Sakhalin Island, earthquake of 27 May 1995: The Island Arc, v.
6
, p.
288
307
.
Jolly
,
R. J. H.
Lonergan
,
L.
,
2002
,
Mechanisms and controls on the formation of sand intrusions: Journal ofthe Geological Society (London)
, v.
159
, p.
605
617
.
Lowe
,
D. R.
,
1982
,
Depositional models with special reference to the deposits of high density turbidity currents: Journal of Sedimentary Petrology
, v.
52
, p.
279
297
.
Newsom
,
J. F.
,
1903
,
Clastic dikes: Geological Society of America Bulletin
, v.
14
, p.
227
268
.
Ramsay
,
J. G.
,
1974
,
Development of chevron folds: Geological Society of America Bulletin
, v.
85
, p.
1741
1754
.
Ratnovskiy
,
i.
,
1960
,
Geologicul structure of the Schmidt Peninsula, Sakhalin: Leningrad, NeUiu
,
104
p.
Raudkivi
,
A. J.
,
1967
,
Loose boundary hydraulics: Oxford, Peigamon Press
,
331
p.
Sandwell
,
D. T.
Sichoix
,
L.
Smith
,
B.
,
2002
,
The 1999 Hector mine earthquake, southern California: Vector near-field displacements from ERS inSAR: Seismolog-ical Society of America Bulletin
, v.
92
, p.
1341
1354
.
Seno
,
T.
Sakurai
,
T.
Stein
,
S.
,
1996
,
Can the Okhotsk plate be distinguished from the North American plate?: Journal of Geophysical Research— Solid Earth
, v.
101
, no. B5, p.
11,305
11,315
.
Stow
,
D. A. V.
,
1985
,
Fine-grained sediments in deep water— An overview of processes and facies models: Geo-Marine Letters
, v.
5
, p.
17
23
.
Tanner
,
P. W. G.
,
1989
,
The flexural-slip mechanism: Journal of Structural Geology
, v.
11
, p.
635
655
.
Taylor
,
B. J.
,
1982
,
Sedimentary dikes, pipes and related structures in the Mesozoic sediments of south-eastern Alexander island: British Antarctic Survey Bulletin
, v.
51
, p.
1
42
.
Thompson
,
B. J.
Garrison
,
R. E.
Moore
,
J. C.
,
2007
,
A reservoir-scale Miocene injectite near Santa Cruz, California
, in
Hurst
,
A.
Cartwright
,
J.
eds., Sand injectites: implications for hydrocarbon exploration and production: AAPG Memoir 87, p.
151
162
.
Vereshchagin
,
V. H.
, et al.,
1969
,
Geologecheskaya karta Sakhalina [Geological map of Sakhalin].
Ministry of Geology of the USSR, scale 1:1,000,000, 1 sheet.
Weaver
,
R.
Roberts
,
A. M.
Flecker
,
R.
Macdonald
,
D. i. M.
,
2004
,
Tertiary geodynamics of Sakhalin (NW Pacific) from anisotropy of magnetic susceptibility fabrics and paleomagnetic data: Tectonophysics
, v.
379
, p.
25
42
.
Webb
,
G. W.
,
1981
,
Stevens and earlier Miocene turbidite sandstones, southern San Joaquin Valley, California: AAPG Bulletin
, v.
65
, p.
438
465
.
Wright
,
T. L.
,
1991
,
Structural geology and tectonic evolution of the Los Angeles basin, California: AAPG Memoir 52
, p.
35
134
.
Zonenshain
,
L. P.
Kuz’min
,
M. i.
Natapov
,
L. V.
,
1990
,
Geology of the USSR: A plate-tectonic synthesis: Washington, D.C., AGU Geodynamics Series 21
,
242
p.

Related

Citing Books via

Close Modal
This Feature Is Available To Subscribers Only

Sign In or Create an Account

Close Modal
Close Modal