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Bokkeveld Group

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Journal Article
Published: 01 September 2020
South African Journal of Geology (2020) 123 (3): 381–398.
...C.R. Penn-Clarke; J.N. Theron Abstract The Tra-Tra Formation is a predominantly argillaceous, shallow marine to paralic sedimentary succession of Eifelian (Middle Devonian) age within the Bokkeveld Group (Cape Supergroup) that crops out extensively within the Cape Fold Belt of South Africa...
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Journal Article
Published: 27 November 2019
Journal of Sedimentary Research (2019) 89 (11): 1140–1170.
... previously been proposed for the Bokkeveld Group. Sequence-stratigraphic analysis of the Bidouw Subgroup suggests that although sedimentation occurred during two large-scale second-order transgressive events, the succession was predominantly regressive. Third-order and fourth-order transgressive–regressive...
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First thumbnail for: Eifelian–Givetian (Middle Devonian) high-paleolati...
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Journal Article
Journal: PALAIOS
Published: 16 April 2019
PALAIOS (2019) 34 (4): 212–228.
...MHAIRI REID; WENDY L. TAYLOR; CARLTON E. BRETT; AARON W. HUNTER; EMESE M. BORDY ABSTRACT The taphonomy of a well preserved ophiuroid-stylophoran assemblage from the Bokkeveld Group, Lower Devonian of South Africa is described using micro-CT scanning techniques. This assemblage provides a taphonomic...
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First thumbnail for: TAPHONOMY AND PALEOECOLOGY OF AN OPHIUROID-STYLOPH...
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Journal Article
Published: 18 September 2018
Journal of Sedimentary Research (2018) 88 (9): 1040–1075.
...Cameron R. Penn-Clarke; Bruce S. Rubidge; Zubair A. Jinnah Abstract Re-evaluation of the sedimentology of the Emsian–Eifelian part of the Bokkeveld Group, the Ceres Subgroup, in the Clanwilliam Sub-basin of South Africa indicates that sedimentation occurred in an array of paleoenvironments...
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First thumbnail for: High-Paleolatitude Environmental Change During the...
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A) Geographic extent of the Bokkeveld Group in the Cape Fold Belt in the Clanwilliam and Aghulas sub-basins (redrawn and modified after Theron and Johnson 1991). B) Simplified geological map of the Cederberg region highlighting northern (Fig. 3A), central (Fig. 3B), and southern (Fig. 3C) study sectors.
Published: 27 November 2019
Fig. 1.— A) Geographic extent of the Bokkeveld Group in the Cape Fold Belt in the Clanwilliam and Aghulas sub-basins (redrawn and modified after Theron and Johnson 1991 ). B) Simplified geological map of the Cederberg region highlighting northern ( Fig. 3 A), central ( Fig. 3 B
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A) Lithostratigraphy of the Bokkeveld Group at its type locality, Klipbokberg, Grootrivierhoogte, Cederberg, in the Western Cape Province. Note the laterally continuous nature of alternating arenaceous and argillaceous lithologies that form the basis for lithostratigraphy. B) Summary of the lithostratigraphy and chronostratigraphy of the Bokkeveld Group in the Clanwilliam and Aghulas sub-basins with respect to expected major lithologies, thicknesses, paleoenvironments, and stacking patterns (Penn-Clarke 2017).
Published: 27 November 2019
Fig. 2.— A) Lithostratigraphy of the Bokkeveld Group at its type locality, Klipbokberg, Grootrivierhoogte, Cederberg, in the Western Cape Province. Note the laterally continuous nature of alternating arenaceous and argillaceous lithologies that form the basis for lithostratigraphy. B) Summary
Image
A) Geographic extent of the Bokkeveld Group within the Cape Fold Belt in the Clanwilliam and Aghulas sub-basins (redrawn and modified after Theron and Johnson 1991). B) Simplified geological map of the Cederberg region highlighting northern (Fig. 3A), central (Fig. 3B), and southern (Fig. 3C) study sectors.
Published: 18 September 2018
Fig. 1.— A) Geographic extent of the Bokkeveld Group within the Cape Fold Belt in the Clanwilliam and Aghulas sub-basins (redrawn and modified after Theron and Johnson 1991 ). B) Simplified geological map of the Cederberg region highlighting northern ( Fig. 3 A), central ( Fig. 3 B
Image
A) Lithostratigraphy of the Bokkeveld Group at its type locality, Klipbokberg, Grootrivierhoogte, Cederberg, Western Cape Province. Note the laterally continuous nature of alternating arenaceous and argillaceous lithologies that form the basis for lithostratigraphy. B) Summary of the lithostratigraphy and chronostratigraphy of the Bokkeveld Group in the Clanwilliam and Aghulas sub-basins with respect to expected major lithologies, thicknesses, paleoenvironments, and stacking patterns (Penn-Clarke 2017).
Published: 18 September 2018
Fig. 2.— A) Lithostratigraphy of the Bokkeveld Group at its type locality, Klipbokberg, Grootrivierhoogte, Cederberg, Western Cape Province. Note the laterally continuous nature of alternating arenaceous and argillaceous lithologies that form the basis for lithostratigraphy. B) Summary
Journal Article
Published: 01 September 1982
Journal of Sedimentary Research (1982) 52 (3): 959–974.
... to storm washover processes. It is suggested that deposition of the entire Bokkeveld Group occurred on arcuate deltas similar to the modern Brazos and Niger deltas. Rates of relative sea-level rise were high and were punctuated by periods of decreased rates or near stillstand. The duration of these stable...
Journal Article
Published: 01 March 2000
South African Journal of Geology (2000) 103 (1): 1–14.
... parasequences each for a total of approximately 3.5 parasequence sets in the lower Witteberg. The lowest parasequence set extends from the base of the Karoopoort Formation (top of underlying Bokkeveld Group) and culminates at the top of the Blinkberg Formation in the Witteberg Group, and approximately 2.5...
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First thumbnail for: Depositional setting and cyclic development of the...
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Journal Article
Published: 01 December 1999
South African Journal of Geology (1999) 102 (4): 391–404.
...P. W. K. Booth; A. J. Munro; R. W. Shone Abstract In this study of Cape Supergroup rocks at Port Alfred, the strata are classified as Witteberg Group rather than the Bokkeveld Group because their lithological characteristics and position in the stratigraphic sequence are similar to Witteberg Group...
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Cape Fold Belt in South Africa. Patterns indicate: cross-ruled — Table Mountain Group, black — Bokkeveld Group, and stippled — Witteberg Group. Arrows indicate localitiçs mentioned in text. Modified from Theron and Loock (1988).
Published: 01 March 2000
Figure 1 Cape Fold Belt in South Africa. Patterns indicate: cross-ruled — Table Mountain Group, black — Bokkeveld Group, and stippled — Witteberg Group. Arrows indicate localitiçs mentioned in text. Modified from Theron and Loock (1988) .
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(A) Location of the stratotype section for the Tra-Tra Formation in the Tra-Tra river valley near Wupperthal, (B) Summary of the litho- and chronostratigraphy of the Bokkeveld Group in the Clanwilliam and Aghulas Sub-basins with respect to expected major lithologies, thicknesses, palaeoenvironments and stacking patterns (modified after Penn-Clarke, et al., 2018a).
Published: 01 September 2020
Figure 1. ( A ) Location of the stratotype section for the Tra-Tra Formation in the Tra-Tra river valley near Wupperthal, ( B ) Summary of the litho- and chronostratigraphy of the Bokkeveld Group in the Clanwilliam and Aghulas Sub-basins with respect to expected major lithologies, thicknesses
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Upward fining package of bedded Enon Formation with predominantly shale clasts from the Bokkeveld Group near Herbertsdale, Mossel Bay Basin. (B) Imbricated disk-shaped shale pebbles and cobbles from the Mossel Bay Basin. (C) Large boulder conglomerate, Mossel Bay Basin. Red dashed line indicates an erosive contact.
Published: 01 June 2017
Figure 3. Upward fining package of bedded Enon Formation with predominantly shale clasts from the Bokkeveld Group near Herbertsdale, Mossel Bay Basin. ( B ) Imbricated disk-shaped shale pebbles and cobbles from the Mossel Bay Basin. ( C ) Large boulder conglomerate, Mossel Bay Basin. Red dashed
Image
Borehole log compared to seismic data. Top left: overview map of borehole SA-1/66, thick red line = seismic line WK-01; arrow = borehole projection along strike; yellow line= seismic profile IyA-200501; background image = 20 m DEM in Figure 2; white dashed lines = BMA maximum axes. Top right: Migrated image of the upper 12 km of seismic reflection profile IyA-200501 and boreholes. Red block = area shown in Figures 5a-c below. (a) Paper record extract of archive seismic line WK-01 and line coincident borehole SA-1/66 superimposed. From the compiled borehole log in Table 1: top of the Ecca Group (E) lie at ~0.5 s TWT; top of the Whitehill- and Prince Albert Formations (Wh/PA) at ~1.1 s TWT; top of the Dwyka Group (D) just above the first reflector at ~1.2 s TWT; top of the Bokkeveld Group (Bo) at ~1.47 s TWT; and top of the Nardouw Formation (N), in the Table Mountain Group (TMG) at ~1.67 s TWT. Black and red horizontal lines mark the top of each group or formation, based on either using interval velocities to convert TWT to depth, or the depths in the borehole logs. (b) Paper record in (a) converted to SEGY data and same horizons marked. Thick black arrow marks the interpreted top of the Dwyka Group above the first horizontal reflector (c) IyA-200501 seismic data and projected borehole log SA-1/66 superimposed. Red vertical lines match stratigraphic units in the seismic image to the corresponding borehole units. The Karoo Supergroup: B = Beaufort Group; E = Ecca Group; Wh/PA = Whitehill- and Prince Albert Formations forming the base of the Ecca Group; D = Dwyka Group. The Cape Supergroup (CSG): Witteberg Group absent and pinched out to the left of the borehole; Bo = Bokkeveld Group; N = Nardouw Formation and P = Peninsula Formation forming part of the Table Mountain Group. Compare (a) and (b), to (c): pale pink = top of the Ecca Group; darker pink = Whitehill- and Prince Albert Formations; brown = top of the Dwyka Group above the first prominent reflector. See text for discussion of the Dwyka contact.
Published: 01 December 2011
: top of the Ecca Group (E) lie at ~0.5 s TWT; top of the Whitehill- and Prince Albert Formations (Wh/PA) at ~1.1 s TWT; top of the Dwyka Group (D) just above the first reflector at ~1.2 s TWT; top of the Bokkeveld Group (Bo) at ~1.47 s TWT; and top of the Nardouw Formation (N), in the Table Mountain
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Depth maps for (a) the base of the main Karoo Basin (base of the Dwyka Group) and (b) the top of the Whitehill Formation (relative to the WGS84 ellipsoid). In (a) the northern extent of the Table Mountain Group (yellow line; solid - definite and dashed –approximate location) and Bokkeveld Group (red line; solid - definite and dashed – approximate location) are shown. The outlines of major tectonic provinces are shown (see Figure 1 for details). Data used to create the maps are shown (seismic – black lines; boreholes – black triangles). Outcropping strata of the Dwyka Group and Whitehill Formation are shown in (a) and (b) respectively (purple). The Msikaba Formation of the Cape Supergroup outcrops between the towns of Margate (MG) and Port St Johns (PStJ) on the east coast. Several towns are indicated (white circles, see Figure 5 for details).
Published: 01 September 2015
) and Bokkeveld Group (red line; solid - definite and dashed – approximate location) are shown. The outlines of major tectonic provinces are shown (see Figure 1 for details). Data used to create the maps are shown (seismic – black lines; boreholes – black triangles). Outcropping strata of the Dwyka Group
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En-echelon folds in Bokkeveld and Table Mountain Group rocks at Humansdorp (100 km west of Port Elizabeth). Simplified after Toerien (1986). H = Humansdorp; J B = Jeffreys Bay.
Published: 01 December 2011
Figure 6. En-echelon folds in Bokkeveld and Table Mountain Group rocks at Humansdorp (100 km west of Port Elizabeth). Simplified after Toerien (1986) . H = Humansdorp; J B = Jeffreys Bay.
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Outlier of upper Bokkeveld and Witteberg Group rocks south of Ladismith (simplified after 1: 250 000 series 3320 Ladismith). This area of outcrop is interpreted as an interference fold structure, where F1 is the earliest phase of folding, and F2 is a subsequent phase of folding.
Published: 01 December 2011
Figure 7. Outlier of upper Bokkeveld and Witteberg Group rocks south of Ladismith (simplified after 1: 250 000 series 3320 Ladismith). This area of outcrop is interpreted as an interference fold structure, where F1 is the earliest phase of folding, and F2 is a subsequent phase of folding.
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(a) Plot of the dolerite thickness distribution within the Karoo Basin from unpublished well logs (modified from Scheiber et al. (2014)). Dolerite thicknesses are indicated: greater than 500 m (red triangles), between 500 and 150 m (orange triangles), less than 150 m (green triangles), and zero dolerites (blue triangles). Soekor seismic lines in the southern part of the basin are marked (black lines). The towns of Fraserburg (FB), Somerset-East (SE), Queenstown (QT), Aliwal North (AN), East London (EL), Beaufort West (BW), Coffee Bay (CB) and Hertzogville (HV) are marked. The dotted line indicates the profile shown in (b). (b) Approximately southwest- northeast profile through the main Karoo Basin, showing the dolerite distribution (horizontal lines) in deep wells QU1/66, AB1/65, KA1/66, VREDE1/66, CR1/68, WE1/66 and SW1/67. Stratigraphic boundaries are marked (dotted lines) and stratigraphic units labelled: BF=Beaufort Group, EC=upper Ecca Group, ES=Ecca shales (Prince Albert and Whitehill Formations), DW=Dwyka Group, BV=Bokkeveld Group (red square), TM=Table Mountain Group (orange triangle), GG=Granite-gneiss basement (blue square). The total well depths are indicated with solid black lines. Over 400 m of dolerite occurs in each well in the east/southeast and northwestern parts of the basin at all stratigraphic levels, while <150 m of dolerite is found in the south-central basin within wells KA1/66, VREDE1/66 and CR1/68. Dolerite in the south-central part of the basin intrudes the Beaufort Group.
Published: 01 June 2021
) and stratigraphic units labelled: BF=Beaufort Group, EC=upper Ecca Group, ES=Ecca shales (Prince Albert and Whitehill Formations), DW=Dwyka Group, BV=Bokkeveld Group (red square), TM=Table Mountain Group (orange triangle), GG=Granite-gneiss basement (blue square). The total well depths are indicated with solid
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(a) Plot of the dolerite thickness distribution as determined from existing reports (Rowsell and De Swardt, 1976) and unpublished log data (see Table 3 for full well names). Dolerite thickness are indicated: greater than 150 m (red triangles), less than 150 m (green triangles), and zero dolerite further south of the dolerite line (blue triangles). Soekor seismic lines in the southern part of the basin are marked (black lines). The surveys (and corresponding wells) are divided into regions, namely the northwestern region around Fraserburg (FB) in the Northern Cape; southwestern region around the town of Graaff-Reinet (GR); and two regions in the southeastern main Karoo Basin close to Somerset-East (SE), and Queenstown (QT) further north. Additional wells exist around Lesotho and the towns of Aliwal North (AN) and East London (EL). Previously interpreted seismic line SWK01 stretches south from Beaufort West (BW) (Fatti and du Toit, 1970). See Figure 1 for details. The dotted line indicates the profile shown in (b). (b) Approximately southwest-northeast profile through the main Karoo Basin, showing the dolerite distribution (horizontal lines) in deep wells QU1/66, AB1/65, KA1/66, VREDE1/66, CR1/68, WE1/66 and SW1/67. Stratigraphic boundaries between wells are marked (dotted lines): BF – Beaufort Group, EC – upper Ecca Group, ES – Ecca shales (lower Ecca shales topped by the Whitehill Formation), DW – Dwyka Group, BV – Bokkeveld Group (red square), TM – Table Mountain Group (orange triangle), GG – Granite-gneiss basement (blue square). The total well depths are indicated with solid black lines. Over 400 m of dolerite occurs in each well in the east/southeast and northwest at all stratigraphic levels, while <150 m of dolerite is found in the southwest wells within the Beaufort Group.
Published: 01 December 2014
, KA1/66, VREDE1/66, CR1/68, WE1/66 and SW1/67. Stratigraphic boundaries between wells are marked (dotted lines): BF – Beaufort Group, EC – upper Ecca Group, ES – Ecca shales (lower Ecca shales topped by the Whitehill Formation), DW – Dwyka Group, BV – Bokkeveld Group (red square), TM – Table Mountain