Skip to Main Content

Abstract

The mid-Cretaceous is an informal term that, in the Middle East, includes the Cretaceous stages of Hauterivian through Cenomanian. During this 37 to 45 million years time interval twenty cycles of relative change of coastal onlap were proposed by Haq et al. (1988), and since that time, some of these cycles have been subdivided further. The average duration of these so-called second-order cycles is 1.8 to 2.2 million years, depending upon which time scale is used.

The challenge is to identify accurately depositional cycles in the stratigraphic record of the Middle East platform and to correlate them precisely with a reference section of cycles. The quantitative stratigraphic technique of graphic correlation achieves this goal. Graphic correlation is a numerical correlation technique that is simple to apply and gives precise and reproducible correlations. Graphic correlation is based on an integrated database of fossil tops and bases and other geologic events. The technique creates hypotheses of correlation that make no assumptions about the completeness of each fossil range.

A composite standard database from the Aptian through the Turonian has been constructed using 42 geologic sections in the Tethyan Realm. More than 1000 bioevents of ammonites, inoceramids, planktic foraminifers, selected rudists, benthic foraminifers, nannofossils, and dinoflagellates have been integrated with nearly 100 depositional and geochemical events. Among these fossils are many of the zonal indicators. The stage boundaries are defined by key taxa in generally accepted reference sections in France, Tunisia, and Texas. The scale is calibrated to the Harland time scale.

Platform exposures of the middle Cretaceous in Oman record six or more global cycle boundaries at the Habshan/Lekhwair contact, at the Shuaiba/Nahr Umr contact, several within the Nahr Umr, possibly at the base and top of the Natih “F” Member, at the top of the “E” Member, and at the contact between the “C” and “B” Members. Other cycles may be recognized as more detailed stratigraphic information is collected.

Sediment accumulation rates progressively increased during deposition of the Albian-Cenomariian carbonate platform. Depositional rate of the Nahr Umr was approximately 1.00 cm/1000 years. Depositional rate of the Natih was about 5.00 cm/1000 years. Clearly, many submarine hiatuses developed during deposition of the Nahr Umr.

Introduction

In the eastern Arabian region of the Tethyan Realm a carbonate platform developed during the middle stages of the Cretaceous from the Hauterivian through the Cenomanian. This study focuses on the latest Aptian through the latest Cenomanian and earliest T uronian cycle of platform deposition, represented by the Wasia Group in Oman and the United Arab Emirates. The duration of this interval ranges from 17.5 to 23 million years, depending on which of four time scales is chosen. The ages vary from 109 to 91.5 Ma on the Haq et al. (1988) scale, 113–90 Ma on the Harland et al. (1990) scale, and 113–93 Ma on the scales of Obradovich (1993) and Gradsteln et al. (1995). Consequently, the duration of depositional cycles will vary accordingly. Haq et al. (1988) delineated eleven cycles from the latest Aptian to the earliest Turonian that ranged in duration from 1.59 to 2.09 million years. Hardenbol et al. (1998) identified seventeen sequence cycles in the European basins during this 20 million year interval. Our evaluation of sequences in Tethyan reference sections in Tunisia and the North American Gulf Coast recognizes sixteen cycles in the same interval (Fig. 1). In the Harland scale this time interval is from 114.6 to 90.1 Ma and the mean cycle duration is 1.53 million years.

Depositional cycles are sedimentary deposits that record fluctuating environmental conditions regardless of duration and genesis (Scott et al., 1994). Longer-term depositional cycles may be bounded by unconformities across the shelf and shelf break, which may be depositional sequences. Shorter-term cycles may be bounded by transgressive contacts that represent a progressive change in depositional conditions. The duration of cycle hierarchy and their genetic mechanisms cannot be assumed from the scale of the cycle only. Some depositional cycles record a depositional episode of shoreline advance and retreat (Galloway, 1989) or of climatic fluctuations. Regardless of their duration or origins, depositional cycles must be defined by physical and biotic data found in the rocks so they can be identified uniquely and consistently from one section to another. A second challenge is to date the cycle duration represented by both the rock and the contact. Generally zonal schemes are unable to measure the duration of the hiatus represented by the contact. A precise, objective, and testable technique must be used to date the cycles. Such a method of quantitative stratigraphy is graphic correlation.

The succession of facies of the Wasia Group has been interpreted to be the result of tectono-eustatic processes (Scott et al., 1988; Scott, 1990a; Alsharhan and Kendall, 1991; Burchette, 1993; Philip et al., 1995) or of eustatic processes primarily (van Buchem et al., 1996; Immenhauser et al., 1997) or of tectonic processes mainly (Rabu et al., 1990; Pratt and Smewing, 1993). The eastern margin of the Arabian platform has been tectonically active and was subjected to intense deformation during the Cretaceous and Tertiary. Dating these events is dependent upon dating the unconformities. However, separating the effects of tectonics from eustasy is difficult. The null hypothesis that unconformities are not the same age as inferred eustatic events could be tested by means of high-precision chronostratigraphy. First, a technique must be available to date precisely the stratal contacts, and second, the contacts must be accurately defined and correlated. Finally, the depositional environments of beds above and below the contacts must be fully understood. New data defining, correlating, and interpreting environments of stratal contacts in the Nahr Umr and Natih Formations are available in Immenhauser et al. (1997), Immenhauser et al. (1999), and Immenhauser et al. (this volume), by Philip et al. (1995), and van Buchem et al. (1996).

Fig. 1.

—Chart of depositiona] and biotic events of the Aptian-Turonian defined in the Midk3 composite standard.

Fig. 1.

—Chart of depositiona] and biotic events of the Aptian-Turonian defined in the Midk3 composite standard.

Graphic Correlation Methodology

Graphic correlation (GC) of sections to a composite standard database is a proven technique (Carney and Pierce 1995; Scott et al., 1994). GC is a quantitative but nonstatistical technique that determines the coeval relationships between two sections by comparing the ranges of taxa in both sections. A graph of any pair of sections is an x-y plot of the tops and bases of taxa found in both sections; it compares the rate of sediment accumulation in one section with that in the other (Carney and Pierce 1995). The GC technique enables the stratigrapher to consider sedimentological events, such as depositional cycles, along with biotic events so that conclusions based on one can be tested by the other. Also, the add ition of event beds, such as ash beds, adds to the precision and accuracy of the correlation.

The elements of a graph are the scaled x-y axes, the tops and bases of the fossils and event beds, and the line of correlation (LOC). The scale of the x axis is in thickness, relative units, or million years. The y axis is scaled in thickness of the measured section or well. Fossil tops are plotted as +’s and bases are n’s. The LOC is positioned by the stratigrapher to indicate the most constrained hypothesis of synchroneity between the two sections. The LOC is placed through the maximum number of tops and bases, and depositional hiatuses indicated by the lithostratigraphic record are shown by horizontal terraces. The position of the LOC is defined by the equation for a regression line. By iteratively graphing numerous sections, a mature composite standard database is constructed of the tops and bases of all taxa, geochemical markers, and key sedimentological strata.

Database

The composite standard (CS) database used in this study consists of data from 42 published outcrop and core-hole data primarily from the Tethyan Realm (Table 1). The ranges of more than 1100 bioevents, planktic and benthic foraminifers, nannofossils, dinoflagellates, ammonites, bivalves, echinoids, calcareous algae, magnetochrons, geochemical events, and sequence stratigraphic markers are defined in this database. This project was initially conceived by W. Schlager and funded at the Free University of Amsterdam with the collaboration of the staff. A. Nederbragt provided verification of foraminiferal taxonomy and range data in selected sections, and B. Fouke provided lithostratigraphy and geochemistry of selected sections.

Table 1.

—List of sections that contributed data to the Midk3 composite standard.

1 Kalaat Senan, Turonian, Tunisia. 22 Nahr Ibrahim Outcrop, Lebanon. 
2 Harland Geologic Time-scale, 1990. 23 Djebel Chenan Aair Outcrop, Lebanon. 
3 Santa Rosa Canyon, Mexico. 24 Mt. Risou, Rosans, SE France. 
4 DSDP 547 Offshore Morocco. 25 Cap Blanc-Nez Outcrop, Northern France. 
5 DSDP 545 Offshore Morocco. 26 Cismon Outcrop, NE Italy. 
6 Type Cenomanian, France. 27 Pie’ del Dosso Outcrop, North-central Italy. 
7 Djebel Mrhila, Tunisia. 28 Estella Outcrop, North-central Spain. 
8 Djebel Bireno, Tunisia. 29 Eastbourne Composite Section, South England 
9 Amoco No. 1 Bounds, Western Kansas. 30 Selbukhra Section, Crimea, Russia. 
10 Kalaat Senan, Cenomanian, Tunisia. 31 Kef el Azreg, Tunisia. 
11 DSDP 386 Offshore USA. 32 Sopeira Section, Pyrenees, Spain. 
12 Boulonnais, Coast of France. 33 Flamicell Section, Pyrenees, Spain. 
13 Piobbico Core, Italy. 34 Montsec Section, Pyrenees, Spain. 
14 DSDP 369A, Offshore Morocco. 35 Peace River Composite, Alberta, Canada. 
15 Pueblo, Colorado Reference Section. 36 Anderson Husky Roros Well, Alberta. 
16 Wadi Mi’aidin Section, Oman (Scott, 1990a). 37 Type Shell Creek Fm., Wyoming. 
17 Wadi Mi’aidin Section (Simmons and Hart, 1987). 38 Ida ou Tanane Outcrop, Morocco. 
18 Shell Chapman Core, South Texas. 39 Chichaoua I Borehole, Morocco. 
19 Shell Tomasek Core, South Texas. 40 Timinoun Outcrop, Morocco. 
20 Trinity River Comp. Section, North Texas. 41 ODP 641C Offshore Portugal. 
21 Austin Comp. Section, Central Texas. 42 Gorgo a Cebara section, Italy. 
1 Kalaat Senan, Turonian, Tunisia. 22 Nahr Ibrahim Outcrop, Lebanon. 
2 Harland Geologic Time-scale, 1990. 23 Djebel Chenan Aair Outcrop, Lebanon. 
3 Santa Rosa Canyon, Mexico. 24 Mt. Risou, Rosans, SE France. 
4 DSDP 547 Offshore Morocco. 25 Cap Blanc-Nez Outcrop, Northern France. 
5 DSDP 545 Offshore Morocco. 26 Cismon Outcrop, NE Italy. 
6 Type Cenomanian, France. 27 Pie’ del Dosso Outcrop, North-central Italy. 
7 Djebel Mrhila, Tunisia. 28 Estella Outcrop, North-central Spain. 
8 Djebel Bireno, Tunisia. 29 Eastbourne Composite Section, South England 
9 Amoco No. 1 Bounds, Western Kansas. 30 Selbukhra Section, Crimea, Russia. 
10 Kalaat Senan, Cenomanian, Tunisia. 31 Kef el Azreg, Tunisia. 
11 DSDP 386 Offshore USA. 32 Sopeira Section, Pyrenees, Spain. 
12 Boulonnais, Coast of France. 33 Flamicell Section, Pyrenees, Spain. 
13 Piobbico Core, Italy. 34 Montsec Section, Pyrenees, Spain. 
14 DSDP 369A, Offshore Morocco. 35 Peace River Composite, Alberta, Canada. 
15 Pueblo, Colorado Reference Section. 36 Anderson Husky Roros Well, Alberta. 
16 Wadi Mi’aidin Section, Oman (Scott, 1990a). 37 Type Shell Creek Fm., Wyoming. 
17 Wadi Mi’aidin Section (Simmons and Hart, 1987). 38 Ida ou Tanane Outcrop, Morocco. 
18 Shell Chapman Core, South Texas. 39 Chichaoua I Borehole, Morocco. 
19 Shell Tomasek Core, South Texas. 40 Timinoun Outcrop, Morocco. 
20 Trinity River Comp. Section, North Texas. 41 ODP 641C Offshore Portugal. 
21 Austin Comp. Section, Central Texas. 42 Gorgo a Cebara section, Italy. 

The following protocols and conventions were followed in the construction of the MIDK3 Composite Standard:

  1. Published data were utilized with foraminiferal taxonomy evaluated by Nederbragt. Authorship of the nannofossil and palynomorph data is indicated in each of the section files.

  2. Where the sample position is given as a depth interval, the base was defined by the shallow end of the interval, and the top by the deeper end of the interval in order to minimize range extensions by sampling.

  3. The scale of the MIDK3 Composite Standard is in mega-annums, and the time scale of Harland et al. (1990) was selected by the Free University group as being the most thoroughly researched at the time. To integrate this scale into the CS, the Kalaat Senan, Tunisia section (1; number refers to section list in Table 1) was taken as a complete record of uniform deposition from the beginning to the end of the Turonian (Fig. 2) (Robaszynski et al., 1993). The positions in meters of the bases of the Turonian and Coniacian as defined by ammonites were plotted to the Harland scale and graphed. The Upper Albian through Lower Turonian section in Santa Rosa Canyon (Fig. 3) (Ice and McNulty, 1980; Ross and McNulty, 1980), Mexico has been shown by unpublished graphic correlation experiments with the Amoco composite standard to represent continuous and uniform deposition. This interval is also represented in the sections of DSDP 547 (4) and DSDP 545 (5) offshore Morocco. The Cenomanian substages were defined in the Cenomanian part of the Kalaat Senan section (Fig. 2) (Robaszynski et al., 1990). The depositional cycles in the Texas sections have been described by Young (1986), Scott (1990b, 1993) Scott et al. (1994), and Yurewicz et al. (1993). The Aptian interval is represented by the Gorgo a Cerbara (43) (Bralower et al., 1994; Cecca et al., 1994) and Pie’ del Dosso, Italy (26) sections (Erba and Quadro, 1987).

  4. Geochemical marker beds defined by the δI3C isotopic ratio were included in the database by selecting the inflection points as the base/top of the peak. Sequence boundaries and other types of depositionally significant contacts are defined in reference sections by the specialists working the sections. They were not used to control the LOC in the reference sections; however, in sections where the paleontological data were wide-ranging they have been used together with biotic events. Milankovitch-scale sedimentary cycles in the U.S. Western Interior Cenomanian were defined in a cored reference section, the Amoco Bounds (9) and in an outcrop at Pueblo, Colorado (15).

  5. Stage/Substage boundary definitions (Table 2) follow, where possible, recommendations of the Second International Symposium on Cretaceous Stage Boundaries in 1995 in Brussels (Rawson et al., 1996).

Fig. 2.

—Cenomanian-Turonian sequence stratigraphy of Kalaat Senan, Tunisia, reference section based on data and analyses by Robaszynski et al. (1990,1993).

Fig. 2.

—Cenomanian-Turonian sequence stratigraphy of Kalaat Senan, Tunisia, reference section based on data and analyses by Robaszynski et al. (1990,1993).

Fig. 3.

—Aptian-Albian sequence stratigraphy of U. S. GuJf Coast and Mexico based on data and analyses by Young (1986), Scott et al. (1988), Scott (1990b, 1993), and Yurewicz et al. (1993).

Fig. 3.

—Aptian-Albian sequence stratigraphy of U. S. GuJf Coast and Mexico based on data and analyses by Young (1986), Scott et al. (1988), Scott (1990b, 1993), and Yurewicz et al. (1993).

Table 2.

—Biomarkers of stage and substage boundaries, the positions of the fossil bases (B) or tops (T) in the reference sections (section number), and their ages by graphic correlation.

Published PositionBioeventReference SectionPaogsitieon in section
B Aptian B CMOR Pie’del Dosso (27) 17.58 m = 124.50 Ma 
B Late Aptian B Eprolithus floralis DSDP 545 (5) 528.4 m = 116.61 Ma 
 alternative: B Dufrenoyia justinae Austin, TX (21) 120 M = 113.99 Ma 
B Albian T Hypacanthoplites cragini Austin, TX (21) 395 ft = 112.00 Ma 
B Mid Albian B Ceratostreon texanum (proxy for L. lyelli) Trinity River, TX (20) 230 ft =108.20 Ma 
B Late Albian B Dipoloceras cristatum Boulonnais (12) 4.2 m = 104.50 Ma 
B Cenomanian B Rotalipora globotruncanoides Risou (24) 136 m = 97.00 Ma 
B Mid Cenomanian B Cunningtoniceras inerme Cap Blanc Nez (25) 27 m = 94.26 Ma 
B Late Cenomanian B Calycoceras naviculare Type Cenoman (6) 88 m = 92.00 Ma 
B Turanian B Watinoceras devonense Pueblo, Colo. (15) 133.9 m = 90.50 Ma 
B Mid Turanian B Romaniceras kallesi Estella Basin (28) 110 m = 90.12 Ma 
B Late Turanian B Romaniceras deverianum Kalaat Senan(1) 678 m = 89.16 Ma 
B Coniacian B Forresteria sp. Kalaat Senan, (1) 947.5 m = 88.50 Ma 
Published PositionBioeventReference SectionPaogsitieon in section
B Aptian B CMOR Pie’del Dosso (27) 17.58 m = 124.50 Ma 
B Late Aptian B Eprolithus floralis DSDP 545 (5) 528.4 m = 116.61 Ma 
 alternative: B Dufrenoyia justinae Austin, TX (21) 120 M = 113.99 Ma 
B Albian T Hypacanthoplites cragini Austin, TX (21) 395 ft = 112.00 Ma 
B Mid Albian B Ceratostreon texanum (proxy for L. lyelli) Trinity River, TX (20) 230 ft =108.20 Ma 
B Late Albian B Dipoloceras cristatum Boulonnais (12) 4.2 m = 104.50 Ma 
B Cenomanian B Rotalipora globotruncanoides Risou (24) 136 m = 97.00 Ma 
B Mid Cenomanian B Cunningtoniceras inerme Cap Blanc Nez (25) 27 m = 94.26 Ma 
B Late Cenomanian B Calycoceras naviculare Type Cenoman (6) 88 m = 92.00 Ma 
B Turanian B Watinoceras devonense Pueblo, Colo. (15) 133.9 m = 90.50 Ma 
B Mid Turanian B Romaniceras kallesi Estella Basin (28) 110 m = 90.12 Ma 
B Late Turanian B Romaniceras deverianum Kalaat Senan(1) 678 m = 89.16 Ma 
B Coniacian B Forresteria sp. Kalaat Senan, (1) 947.5 m = 88.50 Ma 
The age of the base of CMOR is from Rawson et al. (1996) and of the Albian, Cenomanian, Turanian, and Coniacian is from Harland et al. (1990).

Albian-Cenomanian Of Oman

The Wasia Group in Oman consists of the Nahr Umr and Natih Formations (Fig. 4) (Hughes Clarke, 1988; Alsharhan and Nairn, 1988; Alsharhan, 1989). The Wasia is bounded below and above by regional unconformities; it overlies the Aptian Shuaiba Formation and underlies the Coniacian and younger Aruma Group. The Nahr Umr in Oman is an interbedded shale-limestone unit 150 to 200 m thick. This unit represents a regional clastic depositional phase. The contact with the overlying Natih is conformable. The Natih is a limestone unit about 430 m thick that is divided into seven informal subuni ts designated “a” to “g”. The type section of the Natih is a well in Oman, and the outcrop reference section is in Wadi Mi’aidin.

Fig. 4.

—Graphic correlation of the Wasia Group in the Wadi Mi’aidin, Oman section and the Midk3 composite standard 9-98. Section measured and biostratigraphic data analyzed by Simmons and Hart (1987).

Fig. 4.

—Graphic correlation of the Wasia Group in the Wadi Mi’aidin, Oman section and the Midk3 composite standard 9-98. Section measured and biostratigraphic data analyzed by Simmons and Hart (1987).

Basal Nahr Umr Unconformity

The basal contact of the Nahr Umr Formation overlying the Shuaiba Formation is a regional unconformity having a complex history that in outcrop may span up to 2.2 million years or more (Scott et al., 1988). On the platform exposed in the Oman Mountains the Shuaiba is a shallow-water limestone less than 100 m thick (Hughes Clarke, 1988) of Lower Aptian age (Simmons and Hart, 1987; Scott 1990a). To the west in the Bab Basin the Shuaiba is up to 120 m thick, and the uppermost 30–40 m is a dark gray shale and lime mudstone unit called the Bab Member (Alsharhan and Nairn, 1986). These authors report Upper Aptian ammonites in the Bab. A paleontological analysis of diverse fossil groups indicates that the lower part of the Shuaiba is Lower Aptian and the upper part is Upper Aptian (Witt and Gokdag, 1994), although the lower-upper division is ill-defined. The Upper Aptian age of the Bab is supported by the carbon-isotope profiles from wells in the Bab Basin (Vahrenkamp, 1996; Grotsch et al., 1998). Thus, it seems likely that the hiatus at the Shuaiba-Nahr Umr unconformity is greater near the outer platform in the Oman Mountains than in the Bab Basin.

In the basal part of the Shuaiba Formation in the Bab Basin the carbon-isotope curve has a distinct positive inflection from about 2%o to nearly 5%o that is interpreted to be a global signal, OAE la (Wagner, 1990; Vahrenkamp, 1996; Grotsch et al., 1998). This inflection is dated at about 122–120 Ma (Bralower et al., 1994; Erba, 1994; Follmi et al., 1994); Bralower et al. (1994) estimated its duration to be about 0.5 million years. In the Midk3 composite standard database OAE la ranges from 123.05 to 122.32 Ma, 0.73 million years duration, on the basis of the carbon-isotope curve from the section at Cismon, Italy (in Erba, 1994). The positive value of the carbon-isotope curve is maintained to the top of the Shuaiba near the platform margin (Wagner, 1990); no diagenetic negative shift is recorded. However, in the Bab Basin up to three negative shifts of 0.5 to 2%o are present in the lower part of the Shuaiba and in the Bab Member (Vahrenkamp, 1996; Grotsch et al., 1998).

The processes of formation of this Shuaiba-Nahr Umr unconformity are equivocal and Include subaerial exposure (Frost et al., 1983; Immenhauser et al., 1999) and transgressive drowning by sea-level rise (Scott et al., 1988). A regional study of carbon and oxygen isotopes suggested that “little or no evidence exists for a paleo-exposure of the top of the Shuaiba Formation” (Wagner, 1990, p. 130). Likewise/ little or no petrographic evidence of exposure is present in Shuaiba cores in the Sajaa Field, Sharjah, United Arab Emirates (Moshier et al., 1988). However, in the Omani Ghaba North Field, central Oman, petrographic data indicate that the uppermost Shuaiba has experienced meteoric diagenesis (Al-Awar and Humphrey, 1997 and this volume).

Inttra-Nahr Umr Diastems

The Nahr Umr Formation in Oman is composed of repetitive bed-sets of mudstone, wackestone, and orbitolinid packstone bounded at the top by bored, ironstone hardground or firmground surfaces that represent diastems (Simmons and Hart, 1987; Scott, 1990a; Immenhauser et al., 1997; Immenhauser et al., 1999; and Immenhauser et al., this volume). In any given section from one to ten such contacts are recognized by local phosphate nodules and burrows filled with dolomitic, iron-rich micrite (Immenhauser et al., 1999). These surfaces tend to cap incomplete shoaling-up successions of subtidal orbitolinid pack-stone. Immenhauser et al. (1999) correlated many of the surfaces in the Oman Mountains. The hardground surfaces seem to represent a complex sea-level history that began during sea-level fall. A period of subaerial exposure is suggested by distinct negative shifts in carbon and oxygen isotope curves, by brackish-water fluid inclusions, and by soil-forming features (Immenhauser et al., 1999). The final stage was marine flooding and resumption of subtidal deposition.

Natih Disconformitics

Ten hardground disconformities have been identified within and at the top of the Natih Formation (Fig. 5) (van Buchem et al., 1996). We have identified these contacts in the Wadi Mi’aidin section of Philip et al. (1995) and determined their positions in the section so that their ages can be projected by means of the line of correlation in the graph of biostratigraphic data from Philip et al. (1995) (Fig. 5). Van Buchem et al. (1996) did not publish biostratigraphic data for their section.

Fig. 5.

—Graphic correlation of the Natih Formation in the Wadi Mi’aidin, Oman section and the Midk3 composite standard 9-98. Section measured by Philip et al. (1995) and sequence stratigraphic analysis by van Buchem et al. (1996,1997).

Fig. 5.

—Graphic correlation of the Natih Formation in the Wadi Mi’aidin, Oman section and the Midk3 composite standard 9-98. Section measured by Philip et al. (1995) and sequence stratigraphic analysis by van Buchem et al. (1996,1997).

The top of the “e” member of the Natih Formation in Jebel Akhdar is a bored, iron-stained, phosphatic hardground traceable in outcrop and into the subsurface (Scott, 1990a; Wagner, 1990; Philip et al., 1995; van Buchem et al., 1996). Graphic correlation analysis suggested that this disconformity was virtually synchronous in Oman and was coeval with the global mid-Cenomanian sequence boundary (Scott et al., 1988; Scott, 1990a). The marked negative shift in the carbon-isotope signal at the top of the “e” member is evidence of meteoric diagenesis and subaerial exposure (Wagner, 1990). At places as much as seven meters of channelized erosion is evident (van Buchem et al., 1996).

A hardground also is present at the top of the Natih “b” member in some outcrops at Jebel Akhdar (Philip et al., 1995). It is a sharp but non-erosional contact between praealveolinid limestone overlain by basinal lime mudstone. Van Buchem et al. (1996) recognized hardgrounds by the presence of boring, biotur-bation, and iron encrustation in the Natih “c” and “d” members. Four of these surfaces demarcate the bases of their accommodation cycles 5, 6, 7, and 8 and can be traced throughout their sections in the Oman Foothills. They use surfaces 5a, 6a, and 8a as contacts for the tops of members “e”, “d”, and “c”.

The top of the Natih Formation, top “a” member, is a regional unconformity that represents termination of the carbonate platform prior to development of the foreland basin filled with clastics of the Coniacian-Maastrichtian Aruma Group (Rabu et al., 1990; Scott, 1990a; Philip et al., 1995; van Buchem et al., 1996). The surface in many places is thickly encrusted by ironstone and phosphate. The age of the Natih at this surface varies from Late Cenomanian to Early Turonian (Scott, 1990a; Philip eta I., 1995); however, at any one exposure erosional relief is not evident. Subaerial exposure is evident from the isotopic signal (Wagner, 1990), and subsequently the surface was drowned and buried by mainly Coniacian and younger marine sediments. This unconformity was formed by tectonic processes.

Wasia Group Depositional Cycles

Four longer-term depositional cycles were recognized in the Wasia Group: (1) Nahr Umr-Natih members “g” and “f”, (2) Natih member “e”, (3) Natih members “d” and “c”, and (4) Natih members “b” and “a” (Scott, 1990a) (Fig. 4). Philip et al. (1995) used hardground surfaces to define five longer-term cycles: (1) members “g”, “f”, and basa I “e”, (2) member “e”, (3) member “d” (4) member “c”, and (5) members “b” and “a” (Fig. 5). They further subdivided these cycles into shorter-term shoaling-up subcycles. Most recently, van Buchem et al. (1996) and van Buchem et al. (1997) divided the Natih members “e” through “a” into ten medium-term accommodation cycles using the hardground surfaces la at the base of the “e”, 2a, 3a, and 4a within the “e”, 5a at the base of the “d”, 6a at the base of the “c”, 7a within the “c”, 8a at the base of the “b”, and 9a and 10a within the “a” member (Fig. 5). On the basis of paleobathymetry data, they interpreted these as deepening-up to shoaling-up cycles. The contacts of these medium-term cycles were correlated throughout the Oman outcrop belt. These cycles were grouped into three large-scale or third-order cycles using surfaces la, 5a, 7a, and top Natih. Van Buchem et al. (1996) inferred that these were eustatically controlled. The origin of the shorter-term cycles was more complex and uncertain. The correlation of the cycles defined by van Buchem et al. with those of Philip et al. is shown in Figure 5. It appears that placement in the section of the member boundaries is not consistent between these two groups because the positions of these surfaces relative to the member contacts is not the same. However, we matched the cycle surfaces in van Buchem’s unpublished section at Wadi Miaidin with the lithologies in the section by Philip et al. (1995).

Timing Of Discontinuity Contacts

The timing of the several sets of depositional cycles in the Natih Formation in the Wadi Mi’aidi’n section is tested by the technique of graphic correlation. The biostratigraphic data published for this section by Simmons and Hart (1987), Scott (1990a), and Philip et al. (1995) were treated as three separate sections to avoid the problems of integrating three different sets of measurements. The three measured sections can be correlated by means of the lithostratigraphic contacts because they were measured at the same site. The line of correlation (LOC) is constrained by the base and top of the Nahr Umr Formation and the top of the “e” member of the Natih (Fig. 4). Note that a number of fossil bases also constrain the LOC. This graph shows a remarkable change in slope of the LOC, which indicates that the rate of sediment accumulation increased from 1.05 cm/1000 years during Nahr Umr deposition to 5.28 cm/1000 years for the Natih, a five times increase. Previous estimates of this differential rate using a different composite standard database developed by Amoco Corporation were 1.43 and 4.84 cm/1000 years, respectively (Scott, 1990a).

The graph of the Wadi Mi’aidin section (Fig. 4) dates key lithostratigraphic contacts, but the numerous hardgrounds in the Nahr Umr and Natih Formations are not identifiable in the data of Simmons or Scott. The ten hardground horizons in the Nahr Umr are best seen in the Wadi Bani Kharus section of Immenhauser et al. (1997), Immenhauser et al. (1999), and Immenhauser et al. (this volume), where the graph is presented. The base of the LOC in Wadi Bani Kharus is constrained by the bases of Mesorbitolina texana (Roemer) and Mesorbitolina subconcava (Leymerie). The middle segment is bracketed by the bases of Eoradiolites lyratus (Conrad) and Mesorbitolina aperta (Erman). The top of the LOC is constrained by the top of Mesorbitolina subconcava and the top of the Nahr Umr Formation. Such a correlation suggests that this lithostratigraphic contact is synchronous between Wadi Bani Kharus and Wadi Mi’aidin, which is not unreasonable and was proposed by the correlation of Scott (1990a, his fig. 7). The graphic interpretation proposes that Immenhauser’s hardgrounds 1, 2, 5, 6, 8, and 10 correlate with transgressive-regressive depositional cycles in the Upper Aptian through Upper Albian section in north-central Texas (Fig. 6). Also, a maximum-flooding hardground in Wadi Bani Kharus is dated at 108.2 Ma, which correlates with the Al SB FR 1, the base of the transgressive Paluxy Sandstone of the Fredericksburg Group. This correlation suggests that some of the Nahr Umr hardgrounds formed synchronously with relative sea-level changes in the U.S. Gulf Coast that may be the response to global eustatic processes. The other hardgrounds, 3, 4, 7, and 9 may reflect hiatuses formed during maximum flooding, or local sea-level changes responding to tectonism, or eustatic events not recognized or recorded in Texas.

The ten hardgrounds in the Natih Formation defined by van Buchemetal. (1996) and vanBuchemetal. (1997) are dated by the graph of biostratigraphic data of Philip et al. (1995) (Fig. 5). The LOC is well constrained by tops and bases of eight taxa, and the rate of sediment accumulation is 5.14 cm/1000 years, close to that measured in the data of Simmons and Hart (1987) (Fig. 4). Hardgrounds la, 2a, 4a, and 8a correlate with depositional cycles defined in the Tunisian section. Hardgrounds 5a, 6a, 7a, and 9a may correlate with transgressive or downlap surfaces in the Tunisian section (Table 3).

Table 3.

—Comparison of ages inamnneugmas of surfaces separating CAenlobmiaaniann depositional cycles in global reference sections and in Oman

Reference SectionsWadi Bani KharusWadi Miaidin
Ce DL 5 -90. 3   
Ce TS 5 - 90. 8 -90. 7   
Ce SB 5-91. 0-90. 9   
Ce DL 4-92. 3-92. 0  Hg 9a-92. 12 
Ce TS 4 - 92. 6 -92. 0   
Ce SB 4-92. 7-92. 6  Hg 8a - 92. 64 
Ce DL 3 - 93. 24 -93. 16  Hg 7a - 93. 26 
Ce TS 3 - 93. 50  Hg 6a - 93. 36 
Ce SB 3-94. 46-94. 33  Hg 4a-94. 12 
Ce DL 2 - 94. 86   
Ce TS 2 - 95. 01  Hg 2a-95. 18 
Ce SB 2-95. 33-95. 16   
Ce DL 1 - 95. 54   
CeTS 1 -95. 98-95. 78  Hg 1a-95. 85 
Ce SB 1 - 96. 08 -95. 89   
Ce TS 1. 1-96. 64   
Ce SB 1. 1 -97. 0-96. 80 Hg 10-97. 12  
Al TS WA 5 - 98. 43   
 Hg 9-99. 12  
Al TS WA 4 - 99. 78 Hg 8 - 99. 33  
Al TS WA 3-100. 57 Hg 7-100. 85  
Al TS WA 2-101. 85 Hg6- 101. 16  
Al SB WA 1-104. 00-103. 50 Hg 5-103. 03  
Al MF FR 1-106. 9 Hg 4-106. 78  
Al SB FR 1-108. 18 MF- 108. 24  
 Hg 3-110. 26  
Al SB GR 2-111. 26 Hg2-111. 82  
Al SB GR 1-113. 40 Hg 1 -113. 37  
Ap SB PR 2 - 113. 72   
Ap SB SL 1 - 114.57   
Reference SectionsWadi Bani KharusWadi Miaidin
Ce DL 5 -90. 3   
Ce TS 5 - 90. 8 -90. 7   
Ce SB 5-91. 0-90. 9   
Ce DL 4-92. 3-92. 0  Hg 9a-92. 12 
Ce TS 4 - 92. 6 -92. 0   
Ce SB 4-92. 7-92. 6  Hg 8a - 92. 64 
Ce DL 3 - 93. 24 -93. 16  Hg 7a - 93. 26 
Ce TS 3 - 93. 50  Hg 6a - 93. 36 
Ce SB 3-94. 46-94. 33  Hg 4a-94. 12 
Ce DL 2 - 94. 86   
Ce TS 2 - 95. 01  Hg 2a-95. 18 
Ce SB 2-95. 33-95. 16   
Ce DL 1 - 95. 54   
CeTS 1 -95. 98-95. 78  Hg 1a-95. 85 
Ce SB 1 - 96. 08 -95. 89   
Ce TS 1. 1-96. 64   
Ce SB 1. 1 -97. 0-96. 80 Hg 10-97. 12  
Al TS WA 5 - 98. 43   
 Hg 9-99. 12  
Al TS WA 4 - 99. 78 Hg 8 - 99. 33  
Al TS WA 3-100. 57 Hg 7-100. 85  
Al TS WA 2-101. 85 Hg6- 101. 16  
Al SB WA 1-104. 00-103. 50 Hg 5-103. 03  
Al MF FR 1-106. 9 Hg 4-106. 78  
Al SB FR 1-108. 18 MF- 108. 24  
 Hg 3-110. 26  
Al SB GR 2-111. 26 Hg2-111. 82  
Al SB GR 1-113. 40 Hg 1 -113. 37  
Ap SB PR 2 - 113. 72   
Ap SB SL 1 - 114.57   

Conclusions

In order to recognize global eustatic events in the stratigraphic record, hypotheses of synchroneity of depositional surfaces must be tested quantitatively. Graphic correlation is an effective tool, as shown by numerous previous studies, to test such hypotheses. A global, multidisciplinary, quantitative stratigraphic database is necessary to conduct such tests. A database of forty-two middle Cretaceous sections yielding foraminifers, nartnofossils, di-noflagellates, megafossils, magnetochrons, and geochemical shifts was constructed by a team of stratigraphers at the Free University, Amsterdam and Precision Stratigraphy Associates. This database is here applied to testing the synchroneity of hardground surfaces in the Wasia Group, Oman Mountains, with depositional cycles recognized in reference sections (Fig. 6).

Fig. 6.

—Comparison of deposition cycle ages defined in three Tethyan reference sections and in the Albian-Cenomanian sections of Oman. Arrows indicate deepening-shoaling changes.

Fig. 6.

—Comparison of deposition cycle ages defined in three Tethyan reference sections and in the Albian-Cenomanian sections of Oman. Arrows indicate deepening-shoaling changes.

In the latest Aptian-Albian of Texas nine cycles are recognized by shelf-to-basin facies successions and biotic assemblage changes that are separated by locally mappable contacts. The average duration of these cycles is 1.94 million years. In the Cenomanian of Tunisia similar criteria were used in basinal facies to define six cycles that average 1.08 million years in duration. The ages of the defining contacts were constrained in the composite standard database by graphic correlation of diverse fossils.

In Oman, depositional cycles in the Nahr Umr Formation, the basal unit in the Wasia Group, were defined by means of hardgrounds. Petrographic, geochemical, and biofacies data demonstrated the complex history of sea-level fall, exposure, drowning, and resumption of deposition. These contacts were dated by projecting them into a line of correlation constrained by fossil bases and tops and by a stratal contact, between the Nahr Umr and Natih Formations, that is synchronous between two reference sections. Six of ten of the hardgrounds and one maximum flooding contact are of the same age within ± 0.7 million years or less as latest Aptian-Albian cycles in the U.S. Gulf Coast (Table 3).

Depositional cycles of the Natih Formation were defined by petrographic and facies criteria, and their contacts mapped throughout the Oman Mountains. They represent relative sea-level changes. They were dated by projection into the composite standard constrained by fossil tops and bases. Four of ten Natih cycle boundaries correlate closely with Cenomanian sequence boundaries in Tunisia; one correlates with a transgressive surface and two correlate with downlap surfaces. The cycle boundary at the top of the formation is a regional tectonically controlled unconformity that does not correlate with cycles outside of the region. It is reasonable to consider that seven cycles represent the effects of eustatic processes upon the Natih carbonate shelf in Oman.

These hypotheses of correlation of depositional cycles in the Wasia Group with cycles in global reference sections need to be tested further by incorporating more fossil groups from the Oman sections to constrain the lines of correlation more precisely. Further, geochemical analyses of the hardground surfaces in the Natih Formation would evaluate the subaerial exposure origin of these contacts. Finally, correlation of these cycles in sections of other basins is needed to test for their global, and thus eustatic, origins.

References

Al–Awar
,
A.Av
and
Humphrey
,
J.D.
1997
,
Reservoir characterization of the Shu’aiba Formation, Ghaba North Field, Oman
:
GeoArabia
 , v.
2
, p.
476
.
Alsharhan
,
A.S.
1989
,
Petroleum geology of the United Arab Emirates
:
Journal of Petroleum Geology
 , v.
12
, p.
253
288
.
Alsharhan,
,
A.S.
and
Kendall
,
C.G.St.C.
1991
,
Cretaceous chrono– stratigraphy, unconformities and eustatic sea–level changes in the sediments of Abu Dhabi, United Arab Emirates
:
Cretaceous Research
 , v.
12
, p.
379
401
.
Alsharhan
,
A.S.
and
Nairn
,
A.E.M
1986
,
A review of the Cretaceous formations in the Arabian Peninsula and Gulf: Part I. Lower Cretaceous (Thamama Group) stratigraphy and paleogeography
:
Journal of Petroleum Geology
 , v.
9
, p.
365
392
.
Alsharhan
,
A.S.
and
Nairn
,
A.E.M.
1988
,
A review of the Cretaceous formations in the Arabian Peninsula and Gulf: Part II. Mid–Cretaceous (Wasia Group) stratigraphy and paleogeography
:
Journal of Petroleum Geology
 , v.
11
, p.
89
112
.
Bralower
,
T.J.
Artiiur
,
M.A
LucKir
,
R.M.
Slit i:r
,
W.V.
All.vrd
,
D.J.
and
anger
,
S. Schl
1994
,
Timing and paleoceanography of oceanic dysoxia/ anoxia in the Late Barremian to Early Aptian (Early Cretaceous)
:
Palaios
 , v.
9
, p.
335
369
.
Burchette
,
T.P.
1993
,
Mishrif Formation (Cenomanian–Turonian), southern Arabian Gulf: carbonate platform growth along a cra– tonic basin margin
, in
Simo
,
I.A.
Scott
,
R.W.
and
Masse
,
J.–P.
eds.,
Cretaceous Carbonate Platforms
 :
American Association of Petroleum Geologists
,
Memoir
56
, p.
185
199
.
Carney
,
J.L.
and
Pierce
,
R.W.
1995
,
Graphic correlation and composite standard databases as tools for the exploration biostratigrapher
, in
Mann
,
K.O.
and
Lane
,
H.R.
eds.,
Graphic Correlation
 :
SEPM, Special Publication
53
, p.
23
43
.
Cecca
,
F.
Pallini
,
G.
Erba
,
E.
Premoli–Silva
,
I.
and
Coccioni
,
R.
1994
,
Hauterivian–Barremian chronostratigraphy based on ammonites, nannofossils, planktonic foraminifera and magnetic chrons from the Mediterranean domain
:
Cretaceous Research
 , v.
15
, p.
457
467
.
Erba
,
E.
1994
,
Nannofossils and superplumes: the Early Aptian “nannoconid crisis”
:
Paleoceanography
 , v.
9
, p.
483
501
.
Erba
,
E.
and
Quadro
,
B.
1987
,
Biostratigrafia a nannofossili calcarei calpionellidi e formaniferi planktonici delta Maiolica (Titoniano superiore–Aptiano) nelle prealpi Bresciane (Italia Settentrionale)
:
Rivista Italiana di Paleontologia e Stratigrafia
 , v.
93
, p.
3
108
.
Follmi
,
K.B
Wi:issERr
,
H.
Bisping
,
M.
and
Funk
,
H.
1994
,
Phosphogenesis, carbon–isotope stratigraphy, and carbonate–platform evolution a long the Lower Cretaceous northern Tethyan margin
:
Geological Society of America, Bulletin
 , v.
106
, p.
729
746
.
Frost
,
S.H.
Biiefnick
,
D.M.
and
Harris
,
P.M.
1983
,
Deposition and porosity evolution of a Lower Cretaceous rudist buildup, Shuaiba Formation of eastern Arabian Peninsula
:
Society of Economic Paleontologists and Mineralogists, Core Workshop 4
 , p.
38
110
Galloway
,
W.E.
1989
,
Genetic stratigraphic sequences in basin analysis I: Architecture and genesis of flooding–surface bounded depositional units
:
American Association of Petroleum Geologists, Bulletin
 , v.
73
, p.
125
142
.
Gradstedm
,
F.M.
Agterberg
,
F.P.
Occ
,
J.G.
Hardenbol
,
J.
Veen
,
P. Van
Thierry
,
J.
and
Huang
,
Z.
1995
,
A Triassic, Jurassic and Cretaceous time scale
, in
Berggren
,
W.A.
Kent
,
D. V.
Aubry
,
M.P.
and
Hardenbol
,
J.
eds.,
Geochronology, Time Scales, and Global Stratigraphic Correlation
 :
SEPM, Special Publication
54
, p.
95
126
.
GrOfsch
,
J.
Billing
,
I.
and
Vahrenkamp
,
V.
1998
,
Carbon–isotope stratigraphy in shallow–water carbonates: implications for Cretaceous black– shale deposition
:
Sedimentology
 , v.
45
, p.
623
634
.
Haq
,
B.U.
Hardenbol
,
J.
and
Vail
,
P.R.
1988
,
Mesozoic and Cenozoic chronostratigraphy and eustatic cycles
, in
Wilgus
,
C.K.
Hastings
,
B.S.
Posamentier
,
H.
Wagoner
,
J. Van
Ross
,
C.A.
and
Kendall
,
C.G.St.C.
eds.,
Sea–Level Changes: An Integrated Approach
 :
SEPM, Special Publication
42
, p.
71
108
.
Hardenbol
,
J.
Thierry
,
J.
Farley
,
M.B.
Jacquin
,
Th.
deGraciansky
,
P.–C
and
Vail
,
P.R.
1998
,
Mesozoic and Cenozoic sequence chronostratigraphic framework of European Basins
, in
deGraciansky
,
P.–C.
Hardenbol
,
J.
Jacquin
,
Th.
and
Vail
,
P.R.
eds.,
Mesozoic and Cenozoic sequence stratigraphy of European Basins
 :
SEPM, Special Publication
60
, p.
3
13
.
Harland
,
W.B.
Armstrong
,
R.L.
Cox
,
A.V.
Craig
,
L.E.
Smith
,
A.G.
and
Smith
,
D.G.
1990
,
A Geologic Time Scale 1989
:
Cambridge, U.K.
,
Cambridge University Press
,
263
p.
Clark
,
M.W. Huchfs
1988
,
Stratigraphy and rock–unit nomenclature in the oil–producing area of interior Oman
:
Journal of Petroleum Geology
 , v.
11
, p.
5
60
.
Ice
,
R.G.
and
McNulty
,
C.L.
1980
,
Foraminifers and calcispheres from the Cuesta del Cura and lower Agua Nueva(?) Formations (Cretaceous) in east–central Mexico
:
Gulf Coast Association of Geological Societies, Transactions
 , v.
30
, p.
403
425
.
Immlnhauser
,
A.
ager
,
W. Schi
Burns
,
S.J.
and
Scoir
,
R.W.
1997
,
Albian sea–level fluctuations constrained by stable isotopes, fluid inclusions and the morphology of benthic foraminifera (Nahr Umr Formation ) Oman (abstract)
:
GeoArabia
 , v.
2
, p.
486
487
.
Immenhauser
,
A.
Schlager
,
W.
Burns
,
S.J.
Scoit
,
R.W.
Geel
,
T.
Lehmann
,
J.
Van der Gaast
,
S.
and
Bolder–Schrijver
,
L.J.A.
1999
,
Late Aptian to Late Albian sea–level fluctuations constrained by geochemical and biological evidence (Nahr Umr Formation, Oman)
:
Journal of Sedimentary Research
 , v.
69
, p.
434
446
.
Moshier
,
S.O.
Handford
,
C.R.
Scott
,
R.W.
Boutell
,
R.D.
1988
,
Giant gas accumulation in a “chalky”–textured micritic limestone, Lower Cretaceous Shuaiba Formation, Eastern United Arab Emirates
:
SEPM, Core Workshop
 
12
, p.
229
272
.
Obradovich
,
J.D.
1993
,
A Cretaceous time scale
, in
Caldwell
,
W.G.E.
and
Kauffman
,
E.G.
eds.,
Evolution of the Western Interior Basin
 :
Geological Association of Canada
, Special Paper
39
, p.
379
396
.
Philip
,
J.
Borgomano
,
J.
and
Al–Maskiry
,
S.
1995
,
Cenomanian–Early Turonian carbonate platform of northern Oman: stratigraphy and palaeo–environments
:
Palaeogeography, Palaeoclimatology, Palaeoecology
 , v.
119
, p.
77
92
.
Pratt
,
B.R.
and
Smewing
,
J.D.
1993
,
Early Cretaceous platform margin, Oman, eastern Arabian Peninsula
, in
Simo
,
J.A.
Scott
,
R.W.
and
Masse
,
J.–P
eds.,
Cretaceous Carbonate Platforms
 :
American Association of Petroleum Geologists
,
Memoir
56
, p.
201
212
.
Rabu
,
D.
Metour
,
J. Le
Bechennec
,
F.
Beurrier
,
M.
Villey
,
M.
and
Bourdillon–Jeudy de Grissac
,
C.
1990
,
Sedimentary aspects of the Eo– Alpine cycle on the northeast edge of the Arabian platform (Oman Mountains)
, in
Robertson
,
A.H.F.
Searle
,
M.P.
and
Ries
,
A.C.
eds.,
The Geology and Tectonics of the Oman Region
 :
Geological Society of London
, Special Publication
49
, p.
49
68
.
Rawson
,
P.F.
Dhondt
,
A.V
Hancock
,
J.M.
and
Kennedy
,
W.J.
1996
,
Proceedings “Second International Symposium on Cretaceous Stage Boundaries” Brussels
8–16
September
1995
:
Institut Royal des Sciences Naturelles de Belgique
,
Bulletin
,
Sciences de la Terre Aardwetenschappen
 , v.
66
, Supplement,
117
p.
Robaszynski
,
F.
Caron
,
M.
Dunjis
,
C.
Amedro
,
F.
Donoso
,
J.M. Gonzalez
Linares
,
D.
Hardenbol
,
J.
Gartner
,
S.
Calandra
,
F.
and
Deloffre
,
R.
1990
,
A tentative integrated stratigraphy in the Turonian of central Tunisia: formations, zones and sequential stratigraphy in the Kalaat Senan area
:
Bulletin Centres Recherches Exploration–Production Elf– Aquitaine
 , v.
14
, p.
213
384
.
Robaszynski
,
F.
Caron
,
M.
Amedro
,
F.
Dupuis
,
C.
Hardenbol
,
J.
Donoso
,
J.M. Gonzalez
Linares
,
D.
and
Gartner
,
S.
1993
,
Le Cenomanien de la region de Kalaat Senan (Tunisie centrale): Litho–biostratigraphie et interpretation sequentielle
:
Revue de Paleobiologie
 , v.
12
, p.
351
505
.
Ross
,
M. A.
and
McNulty
,
C.L.
1980
,
Some microfossils of the Tamaulipas Limestone (Hauterivian–Lower Albian) in Santa Rose Canyon, Sierra de Santa Rose, Nuevo Leon, Mexico
:
Gulf Coast Association of Geological Societies, Supplement to Transactions
 , v.
31
, p.
461
469
.
Scoir
,
R.W.
1990a
,
Chronostratigraphy of the Cretaceous carbonate shelf, southeastern Arabia
, in
Robertson
,
A.H.F.
Searle
,
M.P.
and
Ries
,
A.C.
eds.,
The Geology and Tectonics of the Oman Region
 :
Geological Society of London
, Special Publication
49
, p.
89
108
.
Scoir
,
R.W.
1990b
,
Models and Stratigraphy of Mid–Cretaceous Reef Communities, Gulf of Mexico
:
SEPM, Concepts in Sedimentology and Paleontology
 , v.
2
,
102
p.
Scon
,
R.W.
1993
,
Cretaceous carbonate platform, U.S. Gulf Coast
, in
Simo
,
J.A.
Scott
,
R.W.
and
Masse
,
J.–P.
eds.,
Cretaceous Carbonate Platforms
 :
American Association of Petroleum Geologists
,
Memoir
56
, p. g
97
109
.
Scott
,
R.W.
Frost
,
S.H.
and
Shaffer
,
B.L.
1988
,
Early Cretaceous sea level curves, Gulf Coast southeastern Arabia
, in
Wilgus
,
C.K.
Hastings
,
B. S.
Posamentier
,
H.
Wagoner
,
J. Van
Ross
,
C.A.
and
Kendall
,
C.G.St.C.
eds.,
Sea–Level Changes: An Integrated Approach
 :
SEPM, Special Publication
42
, p.
275
284
.
Scott
,
R.W.
Franks
,
P.C.
Stein
,
J.A.
Bergen
,
J.A.
and
Evetts
,
M.J.
1994
,
Graphic correlation tests the synchronous Mid–Cretaceous depositional cycles: Western interior and Gulf Coast
, in
Dolson
,
J.C.
ed.,
Unconformity–Related Hydrocarbons Ln Sedimentary Sequences
 :
Rocky Mountain Association Geologists
, p.
89
98
.
Simmons
,
M.D.
and
Hart
,
M.B.
1987
,
The biostratigraphy and microfa– cies of the Early to mid–Cretaceous carbonates of Wadi Mi’aidin, central Oman Mountains
, in
Hart
,
M.B.
ed.,
Micropalaeontology of Carbonate Environments
 :
Chichester, UK
,
Ellis Horwood Ltd.
, p.
176
207
.
Vahrenkamp
,
V.C.
1996
,
Carbon isotope stratigraphy of the upper Kharaib and Shuaiba Formations: implications for the Early Cretaceous evolution of the Arabian Gulf region
:
American Association Petroleum of Geologists, Bulletin
 , v.
80
, p.
647
662
.
Buchem
,
F.S.P. Van
Razin
,
P.
Homewood
,
P.W.
Philip
,
J.M.
Eberli
,
G.P.
Platel
,
J.–P.
Roger
,
J.
Eschard
,
R.
Dpsaubliaux
,
G.M.J.
Boisseau
,
T.
Leduc
,
J.–P.
Labourdette
,
R.
and
Cantaloube
,
S.
1996
,
High resolution sequence stratigraphy of the Natih Formation (Cenomanian/ Turonian) in northern Oman: distribution of source rocks and reservoir rocks
:
GeoArabia
 , v.
1
, p.
65
91
.
Buchem
,
F.S.P. Van
Razin
,
P.
Casanova
,
P.
Homewood
,
P.W.
Walgpnwitz
,
F.
Schwab
,
A.
Oterdoon
,
H.
and
Philip
,
J.M.
1997
,
The stratigraphic architecture of the Cenomanian/Turonian carbonate petroleum system in Natih Formation northern Oman (abstract)
:
GeoArabia
 , v.
2
, p.
496
.
Wagner
,
P.D
1990
,
Geochemical stratigraphy and porosity controls in Cretaceous carbonates near the Oman Mountains
, in
Robertson
,
A.H.F.
Searle
,
M.P.
and
Ries
,
A.C.
eds.,
The Geology and Tectonics of the Oman Region
 :
Geological Society of London
, Special Publication
49
, p.
127
137
.
Witt
,
W.
and
Gokdag
,
H.
1994
,
Orbitolinid biostratigraphyof the Shuaiba Formation (Aptian), Oman—implications for reservoir development
, in
Simmons
,
M.D.
ed.,
Micropalaeontology and Hydrocarbon Exploration in the Middle East
 :
London
,
Chapman &: Hall
, p.
221
241
.
Young
,
K.
1986
,
Cretaceous, marine inundations of the San Marcos Platform, Texas
:
Cretaceous Research
 , v.
7
, p.
117
140
.
Yurewicz
,
D.A.
Marler
,
T.B.
Mlyerholtz
,
K.A.
and
Siroky
,
F.X.
1993
,
Early Cretaceous carbonate platform, north rim of the Gulf of Mexico, Mississippi and Louisiana
, in
Simo
,
J.A.
Scott
,
R.W.
and
Masse
,
J.–P.
eds.,
Cretaceous Carbonate Platforms
 :
American Association of Petroleum Geologists
,
Memoir
56
, p.
81
97
.

Acknowledgments

Amoco Corporation is credited with the pioneering application of quantitative stratigraphic techniques to practical stratigraphic problems and with the development of procedures to construct composite standard databases. The Free University at Amsterdam provided financial support to begin the construction of a database to test the synchroneity of Cretaceous depositional events. Encouragement and advice on taxonomic questions were provided by J. A. Bergen, R. W. Hedlund, B. A. Masters, and J. A. Stein. Stimulating and fruitful discussions about Cretaceous cycles in the Middle East were shared with A.S. Alsharhan, E.J. Kauffman, and C. G. St. C. Kendall.

Figures & Tables

Contents

GeoRef

References

References

Al–Awar
,
A.Av
and
Humphrey
,
J.D.
1997
,
Reservoir characterization of the Shu’aiba Formation, Ghaba North Field, Oman
:
GeoArabia
 , v.
2
, p.
476
.
Alsharhan
,
A.S.
1989
,
Petroleum geology of the United Arab Emirates
:
Journal of Petroleum Geology
 , v.
12
, p.
253
288
.
Alsharhan,
,
A.S.
and
Kendall
,
C.G.St.C.
1991
,
Cretaceous chrono– stratigraphy, unconformities and eustatic sea–level changes in the sediments of Abu Dhabi, United Arab Emirates
:
Cretaceous Research
 , v.
12
, p.
379
401
.
Alsharhan
,
A.S.
and
Nairn
,
A.E.M
1986
,
A review of the Cretaceous formations in the Arabian Peninsula and Gulf: Part I. Lower Cretaceous (Thamama Group) stratigraphy and paleogeography
:
Journal of Petroleum Geology
 , v.
9
, p.
365
392
.
Alsharhan
,
A.S.
and
Nairn
,
A.E.M.
1988
,
A review of the Cretaceous formations in the Arabian Peninsula and Gulf: Part II. Mid–Cretaceous (Wasia Group) stratigraphy and paleogeography
:
Journal of Petroleum Geology
 , v.
11
, p.
89
112
.
Bralower
,
T.J.
Artiiur
,
M.A
LucKir
,
R.M.
Slit i:r
,
W.V.
All.vrd
,
D.J.
and
anger
,
S. Schl
1994
,
Timing and paleoceanography of oceanic dysoxia/ anoxia in the Late Barremian to Early Aptian (Early Cretaceous)
:
Palaios
 , v.
9
, p.
335
369
.
Burchette
,
T.P.
1993
,
Mishrif Formation (Cenomanian–Turonian), southern Arabian Gulf: carbonate platform growth along a cra– tonic basin margin
, in
Simo
,
I.A.
Scott
,
R.W.
and
Masse
,
J.–P.
eds.,
Cretaceous Carbonate Platforms
 :
American Association of Petroleum Geologists
,
Memoir
56
, p.
185
199
.
Carney
,
J.L.
and
Pierce
,
R.W.
1995
,
Graphic correlation and composite standard databases as tools for the exploration biostratigrapher
, in
Mann
,
K.O.
and
Lane
,
H.R.
eds.,
Graphic Correlation
 :
SEPM, Special Publication
53
, p.
23
43
.
Cecca
,
F.
Pallini
,
G.
Erba
,
E.
Premoli–Silva
,
I.
and
Coccioni
,
R.
1994
,
Hauterivian–Barremian chronostratigraphy based on ammonites, nannofossils, planktonic foraminifera and magnetic chrons from the Mediterranean domain
:
Cretaceous Research
 , v.
15
, p.
457
467
.
Erba
,
E.
1994
,
Nannofossils and superplumes: the Early Aptian “nannoconid crisis”
:
Paleoceanography
 , v.
9
, p.
483
501
.
Erba
,
E.
and
Quadro
,
B.
1987
,
Biostratigrafia a nannofossili calcarei calpionellidi e formaniferi planktonici delta Maiolica (Titoniano superiore–Aptiano) nelle prealpi Bresciane (Italia Settentrionale)
:
Rivista Italiana di Paleontologia e Stratigrafia
 , v.
93
, p.
3
108
.
Follmi
,
K.B
Wi:issERr
,
H.
Bisping
,
M.
and
Funk
,
H.
1994
,
Phosphogenesis, carbon–isotope stratigraphy, and carbonate–platform evolution a long the Lower Cretaceous northern Tethyan margin
:
Geological Society of America, Bulletin
 , v.
106
, p.
729
746
.
Frost
,
S.H.
Biiefnick
,
D.M.
and
Harris
,
P.M.
1983
,
Deposition and porosity evolution of a Lower Cretaceous rudist buildup, Shuaiba Formation of eastern Arabian Peninsula
:
Society of Economic Paleontologists and Mineralogists, Core Workshop 4
 , p.
38
110
Galloway
,
W.E.
1989
,
Genetic stratigraphic sequences in basin analysis I: Architecture and genesis of flooding–surface bounded depositional units
:
American Association of Petroleum Geologists, Bulletin
 , v.
73
, p.
125
142
.
Gradstedm
,
F.M.
Agterberg
,
F.P.
Occ
,
J.G.
Hardenbol
,
J.
Veen
,
P. Van
Thierry
,
J.
and
Huang
,
Z.
1995
,
A Triassic, Jurassic and Cretaceous time scale
, in
Berggren
,
W.A.
Kent
,
D. V.
Aubry
,
M.P.
and
Hardenbol
,
J.
eds.,
Geochronology, Time Scales, and Global Stratigraphic Correlation
 :
SEPM, Special Publication
54
, p.
95
126
.
GrOfsch
,
J.
Billing
,
I.
and
Vahrenkamp
,
V.
1998
,
Carbon–isotope stratigraphy in shallow–water carbonates: implications for Cretaceous black– shale deposition
:
Sedimentology
 , v.
45
, p.
623
634
.
Haq
,
B.U.
Hardenbol
,
J.
and
Vail
,
P.R.
1988
,
Mesozoic and Cenozoic chronostratigraphy and eustatic cycles
, in
Wilgus
,
C.K.
Hastings
,
B.S.
Posamentier
,
H.
Wagoner
,
J. Van
Ross
,
C.A.
and
Kendall
,
C.G.St.C.
eds.,
Sea–Level Changes: An Integrated Approach
 :
SEPM, Special Publication
42
, p.
71
108
.
Hardenbol
,
J.
Thierry
,
J.
Farley
,
M.B.
Jacquin
,
Th.
deGraciansky
,
P.–C
and
Vail
,
P.R.
1998
,
Mesozoic and Cenozoic sequence chronostratigraphic framework of European Basins
, in
deGraciansky
,
P.–C.
Hardenbol
,
J.
Jacquin
,
Th.
and
Vail
,
P.R.
eds.,
Mesozoic and Cenozoic sequence stratigraphy of European Basins
 :
SEPM, Special Publication
60
, p.
3
13
.
Harland
,
W.B.
Armstrong
,
R.L.
Cox
,
A.V.
Craig
,
L.E.
Smith
,
A.G.
and
Smith
,
D.G.
1990
,
A Geologic Time Scale 1989
:
Cambridge, U.K.
,
Cambridge University Press
,
263
p.
Clark
,
M.W. Huchfs
1988
,
Stratigraphy and rock–unit nomenclature in the oil–producing area of interior Oman
:
Journal of Petroleum Geology
 , v.
11
, p.
5
60
.
Ice
,
R.G.
and
McNulty
,
C.L.
1980
,
Foraminifers and calcispheres from the Cuesta del Cura and lower Agua Nueva(?) Formations (Cretaceous) in east–central Mexico
:
Gulf Coast Association of Geological Societies, Transactions
 , v.
30
, p.
403
425
.
Immlnhauser
,
A.
ager
,
W. Schi
Burns
,
S.J.
and
Scoir
,
R.W.
1997
,
Albian sea–level fluctuations constrained by stable isotopes, fluid inclusions and the morphology of benthic foraminifera (Nahr Umr Formation ) Oman (abstract)
:
GeoArabia
 , v.
2
, p.
486
487
.
Immenhauser
,
A.
Schlager
,
W.
Burns
,
S.J.
Scoit
,
R.W.
Geel
,
T.
Lehmann
,
J.
Van der Gaast
,
S.
and
Bolder–Schrijver
,
L.J.A.
1999
,
Late Aptian to Late Albian sea–level fluctuations constrained by geochemical and biological evidence (Nahr Umr Formation, Oman)
:
Journal of Sedimentary Research
 , v.
69
, p.
434
446
.
Moshier
,
S.O.
Handford
,
C.R.
Scott
,
R.W.
Boutell
,
R.D.
1988
,
Giant gas accumulation in a “chalky”–textured micritic limestone, Lower Cretaceous Shuaiba Formation, Eastern United Arab Emirates
:
SEPM, Core Workshop
 
12
, p.
229
272
.
Obradovich
,
J.D.
1993
,
A Cretaceous time scale
, in
Caldwell
,
W.G.E.
and
Kauffman
,
E.G.
eds.,
Evolution of the Western Interior Basin
 :
Geological Association of Canada
, Special Paper
39
, p.
379
396
.
Philip
,
J.
Borgomano
,
J.
and
Al–Maskiry
,
S.
1995
,
Cenomanian–Early Turonian carbonate platform of northern Oman: stratigraphy and palaeo–environments
:
Palaeogeography, Palaeoclimatology, Palaeoecology
 , v.
119
, p.
77
92
.
Pratt
,
B.R.
and
Smewing
,
J.D.
1993
,
Early Cretaceous platform margin, Oman, eastern Arabian Peninsula
, in
Simo
,
J.A.
Scott
,
R.W.
and
Masse
,
J.–P
eds.,
Cretaceous Carbonate Platforms
 :
American Association of Petroleum Geologists
,
Memoir
56
, p.
201
212
.
Rabu
,
D.
Metour
,
J. Le
Bechennec
,
F.
Beurrier
,
M.
Villey
,
M.
and
Bourdillon–Jeudy de Grissac
,
C.
1990
,
Sedimentary aspects of the Eo– Alpine cycle on the northeast edge of the Arabian platform (Oman Mountains)
, in
Robertson
,
A.H.F.
Searle
,
M.P.
and
Ries
,
A.C.
eds.,
The Geology and Tectonics of the Oman Region
 :
Geological Society of London
, Special Publication
49
, p.
49
68
.
Rawson
,
P.F.
Dhondt
,
A.V
Hancock
,
J.M.
and
Kennedy
,
W.J.
1996
,
Proceedings “Second International Symposium on Cretaceous Stage Boundaries” Brussels
8–16
September
1995
:
Institut Royal des Sciences Naturelles de Belgique
,
Bulletin
,
Sciences de la Terre Aardwetenschappen
 , v.
66
, Supplement,
117
p.
Robaszynski
,
F.
Caron
,
M.
Dunjis
,
C.
Amedro
,
F.
Donoso
,
J.M. Gonzalez
Linares
,
D.
Hardenbol
,
J.
Gartner
,
S.
Calandra
,
F.
and
Deloffre
,
R.
1990
,
A tentative integrated stratigraphy in the Turonian of central Tunisia: formations, zones and sequential stratigraphy in the Kalaat Senan area
:
Bulletin Centres Recherches Exploration–Production Elf– Aquitaine
 , v.
14
, p.
213
384
.
Robaszynski
,
F.
Caron
,
M.
Amedro
,
F.
Dupuis
,
C.
Hardenbol
,
J.
Donoso
,
J.M. Gonzalez
Linares
,
D.
and
Gartner
,
S.
1993
,
Le Cenomanien de la region de Kalaat Senan (Tunisie centrale): Litho–biostratigraphie et interpretation sequentielle
:
Revue de Paleobiologie
 , v.
12
, p.
351
505
.
Ross
,
M. A.
and
McNulty
,
C.L.
1980
,
Some microfossils of the Tamaulipas Limestone (Hauterivian–Lower Albian) in Santa Rose Canyon, Sierra de Santa Rose, Nuevo Leon, Mexico
:
Gulf Coast Association of Geological Societies, Supplement to Transactions
 , v.
31
, p.
461
469
.
Scoir
,
R.W.
1990a
,
Chronostratigraphy of the Cretaceous carbonate shelf, southeastern Arabia
, in
Robertson
,
A.H.F.
Searle
,
M.P.
and
Ries
,
A.C.
eds.,
The Geology and Tectonics of the Oman Region
 :
Geological Society of London
, Special Publication
49
, p.
89
108
.
Scoir
,
R.W.
1990b
,
Models and Stratigraphy of Mid–Cretaceous Reef Communities, Gulf of Mexico
:
SEPM, Concepts in Sedimentology and Paleontology
 , v.
2
,
102
p.
Scon
,
R.W.
1993
,
Cretaceous carbonate platform, U.S. Gulf Coast
, in
Simo
,
J.A.
Scott
,
R.W.
and
Masse
,
J.–P.
eds.,
Cretaceous Carbonate Platforms
 :
American Association of Petroleum Geologists
,
Memoir
56
, p. g
97
109
.
Scott
,
R.W.
Frost
,
S.H.
and
Shaffer
,
B.L.
1988
,
Early Cretaceous sea level curves, Gulf Coast southeastern Arabia
, in
Wilgus
,
C.K.
Hastings
,
B. S.
Posamentier
,
H.
Wagoner
,
J. Van
Ross
,
C.A.
and
Kendall
,
C.G.St.C.
eds.,
Sea–Level Changes: An Integrated Approach
 :
SEPM, Special Publication
42
, p.
275
284
.
Scott
,
R.W.
Franks
,
P.C.
Stein
,
J.A.
Bergen
,
J.A.
and
Evetts
,
M.J.
1994
,
Graphic correlation tests the synchronous Mid–Cretaceous depositional cycles: Western interior and Gulf Coast
, in
Dolson
,
J.C.
ed.,
Unconformity–Related Hydrocarbons Ln Sedimentary Sequences
 :
Rocky Mountain Association Geologists
, p.
89
98
.
Simmons
,
M.D.
and
Hart
,
M.B.
1987
,
The biostratigraphy and microfa– cies of the Early to mid–Cretaceous carbonates of Wadi Mi’aidin, central Oman Mountains
, in
Hart
,
M.B.
ed.,
Micropalaeontology of Carbonate Environments
 :
Chichester, UK
,
Ellis Horwood Ltd.
, p.
176
207
.
Vahrenkamp
,
V.C.
1996
,
Carbon isotope stratigraphy of the upper Kharaib and Shuaiba Formations: implications for the Early Cretaceous evolution of the Arabian Gulf region
:
American Association Petroleum of Geologists, Bulletin
 , v.
80
, p.
647
662
.
Buchem
,
F.S.P. Van
Razin
,
P.
Homewood
,
P.W.
Philip
,
J.M.
Eberli
,
G.P.
Platel
,
J.–P.
Roger
,
J.
Eschard
,
R.
Dpsaubliaux
,
G.M.J.
Boisseau
,
T.
Leduc
,
J.–P.
Labourdette
,
R.
and
Cantaloube
,
S.
1996
,
High resolution sequence stratigraphy of the Natih Formation (Cenomanian/ Turonian) in northern Oman: distribution of source rocks and reservoir rocks
:
GeoArabia
 , v.
1
, p.
65
91
.
Buchem
,
F.S.P. Van
Razin
,
P.
Casanova
,
P.
Homewood
,
P.W.
Walgpnwitz
,
F.
Schwab
,
A.
Oterdoon
,
H.
and
Philip
,
J.M.
1997
,
The stratigraphic architecture of the Cenomanian/Turonian carbonate petroleum system in Natih Formation northern Oman (abstract)
:
GeoArabia
 , v.
2
, p.
496
.
Wagner
,
P.D
1990
,
Geochemical stratigraphy and porosity controls in Cretaceous carbonates near the Oman Mountains
, in
Robertson
,
A.H.F.
Searle
,
M.P.
and
Ries
,
A.C.
eds.,
The Geology and Tectonics of the Oman Region
 :
Geological Society of London
, Special Publication
49
, p.
127
137
.
Witt
,
W.
and
Gokdag
,
H.
1994
,
Orbitolinid biostratigraphyof the Shuaiba Formation (Aptian), Oman—implications for reservoir development
, in
Simmons
,
M.D.
ed.,
Micropalaeontology and Hydrocarbon Exploration in the Middle East
 :
London
,
Chapman &: Hall
, p.
221
241
.
Young
,
K.
1986
,
Cretaceous, marine inundations of the San Marcos Platform, Texas
:
Cretaceous Research
 , v.
7
, p.
117
140
.
Yurewicz
,
D.A.
Marler
,
T.B.
Mlyerholtz
,
K.A.
and
Siroky
,
F.X.
1993
,
Early Cretaceous carbonate platform, north rim of the Gulf of Mexico, Mississippi and Louisiana
, in
Simo
,
J.A.
Scott
,
R.W.
and
Masse
,
J.–P.
eds.,
Cretaceous Carbonate Platforms
 :
American Association of Petroleum Geologists
,
Memoir
56
, p.
81
97
.

Related

Citing Books via

Close Modal
This Feature Is Available To Subscribers Only

Sign In or Create an Account

Close Modal
Close Modal