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![Fransfontein Ridge (Namibia) geology in the vicinity of sample DW-1. See Figure 1 for location. Fm—formation; ls—limestone; ds—dolostone.]()
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![(A) North-south stratigraphic cross section and composite carbon isotope record of the Otavi Group on the southern and western flanks of the Kamanjab inlier (Fig. 1B), Namibia (Halverson et al., 2005). Shaded rectangle on inset map of southern Africa (lower right) gives area of part B. Tanz.—Tanzania; Zam.—Zambia; Mal.—Malawi; Zim.—Zimbabwe; Nam.—Namibia; Bots.—Botswana; Moz.—Mozambique; Swaz.—Swaziland. (B) Setting of the Kamanjab inlier with Fransfontein homocline on its southern margin (rectangle gives area of Fig. 1C). Ru—Ruacana; Op—Opuwu; Ka—Kamanjab; Kh—Khorixas; Ou—Outjo; Ot—Otavi; Ko—Kombat; Gr—Grootfontein; Ts—Tsumeb. (C) Setting of Fransfontein homocline showing inferred shelf break (platform-foreslope boundary) and transition between the upper and distal (lower) foreslope.]()
![Composite boron and carbon (B, C) isotope record and paleo-pH reconstruction across Neoproterozoic Chuos and Ghaub glacials and subsequent greenhouse transitions on southern Congo craton in northern Namibia. Rasthof cap carbonate of Chuos glacial includes two separate sections, Fransfontein (closed circles) and Entrance (open circles). Ombaatjie Formation is from eponymous type locality. Keilberg-Maieberg Formation cap sequence of Ghaub glacial and overlying Elandshoek Formation is from Fransfontein section. Gray area marks average B isotope composition and ocean pH conditions of inferred Neoproterozoic climatic normalcy. Arrow indicates inferred transient ocean acidification event. Note that the stratigraphic interval between top of Rasthof Formation and base of Ombaatjie Formation at Fransfontein and at Entrance was not sampled; stratigraphic thicknesses are 14 m and 283 m, respectively. cc—carbonate carbon.]()
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![Stratigraphic column of investigated sections with corresponding δ11B (‰) and δ13Ccarb (‰) isotope data and estimated ocean pH. Gray shaded area marks cap carbonates. A: Kyrshabakty section, Malyi Karatau microcontinent, Kazakhstan. B: Northern Xiaofenghe section, Yangtze Platform, south China. C: Ombaatjie section, Congo craton, Namibia. D: Khowarib section, Congo craton, Namibia. E: Fransfontein section, Congo craton, Namibia. AT—Aktas tillite; NT—Nantuo tillite; GG—Ghaub glacial deposit; KM—Keilberg Member.]()
![Simplified stratigraphy of the Fransfontein Ridge area around Duurwater and the Navachab area, Namibia (for details of Navachab, see Hoffmann et al., 2004); left column is a detailed section showing the stratigraphic position of the DW-1 ash bed, the middle of three ash beds, within the diamictic interval of the Ghaub Formation. Mbr—member; Fm—formation; ds—dolostone.]()
![Outcrop belt of the autochthonous Otavi Group in northern Namibia (Hedberg, 1981), showing approximate trace of the foreslope-platform break (dashed white line). Rectangular box gives location of the Fransfontein Ridge. Towns: Gr, Grootberg; Ka, Kamanjab; Kh, Khorixas; Ko, Kombat; Op, Opuwa; Ot, Otavi; Ou, Outjo; Ru, Ruacana; Ts, Tsumeb.]()
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![A: Geological sketch of Malyi and Bolshoi Karatau Range (Kazakhstan) displaying study area east of Zhanatas (modified after Alexeiev et al., 2009). YNG—younger. B: Generalized map of Chinese Yangtze Platform including northern Xiaofenghe section, Hubei Province (modified after Cremonese et al., 2013). C: Generalized geological map of northern Namibia showing locations of Fransfontein, Ombaatjie, and Khowarib sections (modified after Kasemann et al., 2010).]()
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![(A) Satellite image of outcrop belt of the Fransfontein homocline in north-central Namibia with locations of sections (see Fig. 1C for location). Locations of low-altitude oblique photos are given as Figures 5–8 and 10, as indicated. Stratigraphic units: B—basement; R—Rasthof Formation; N—Narachaams Member; F—Franni-aus Member; G—Ghaub Formation; M—Maieberg Formation; E—Elandshoek Formation; H—Huttenberg Formation. (B) Perspective of western end of Fransfontein homocline as viewed eastward, above route C35 (white arrow to right in Fig. 2A) with contacts of major stratigraphic divisions. (C) Stratigraphic-paleogeographic restoration of the Otavi platform and foreslope after deposition of the Maieberg cap-carbonate sequence. Marinoan glacial erosion surface features a raised outer platform and preferentially eroded inner platform and upper foreslope. The Franni-aus falling-stand wedge and Ghaub ice grounding-line wedge (in red) are situated on the distal foreslope at reconstructed elevations >1.2 km below the rim of the platform (wrt—with respect to). The Keilberg cap dolostone is a transgressive peloidal grainstone deposited diachronously above wave base in all areas during terminal glacioeustatic flooding.]()
![Figure 1. Carbon isotopic data from preglacial, glacial, and postglacial cap carbonate rocks in northeastern Amadeus basin, central Australia (A), southern Congo Craton, Namibia (B and C), and eastern California (D). No time relationship or correlation within or between glacial intervals is implied other than relative stratigraphic position at single localities and whether carbonate samples were obtained from base, middle, or top of glacial successions. Gray symbols and numbers in A (Mount Capitor) and B (Fransfontein Ridge) indicate data reported from Kennedy et al. (1998). Additional geochemical and location information is available from GSA Data Repository (see text footnote 1). Detail of glacial interval (Ghaub Formation, C) shows two sections with laminated dolomicrite compared to clasts (lonestones). Horizontal lines indicate range of isotopic values within seven clasts. Vertical thickness scale for Fransfontein Ridge and Mount Capitor (gray circles) sections is double that shown in C and A, respectively. Data shown in D are from three intervals in glaciogenic Kingston Peak Formation and postglacial Noonday Dolomite, including ooid grainstone from middle of Kingston Peak, and bedded dolomicrite from transition into Noonday Dolomite (Wildrose Diamictite of Prave, 1999). Data and stratigraphic relations for dolomicrite and oncolitic dolomite in Virgin Spring limestone are from Tucker (1986)]()
![A,B: δ13C (A) and δ11B (B) measured in bulk carbonates from snowball Earth cap carbonates of Ghaub Formation at Fransfontein in Namibia (Kasemann et al., 2010), for comparison with diagenetically altered upper sequence of Pliocene–Pleistocene Clino core (Grand Bahama Bank, western Atlantic Ocean). C–E: δ13C (C) and δ18O (D) data from Clino core (Melim et al., 1995) shown with δ11B data (E; this study). F–I: B/Ca, Na/Ca, Mg/Ca, and Sr/Ca ratios from Clino core. Gray horizontal bar in A and B highlights suggested interval of ocean acidification following Marinoan glaciation, as inferred from negative shift in δ11B, while in Clino core records (C–I), gray bar represents zone of meteoric diagenesis that has produced non-primary isotopic and trace element shifts.]()
![Comparisons of the carbon isotopic records of four Pliocene–Pleistocene cores taken from Caribbean (Melim et al., 2004, 2002) and Pacific (Quinn, 1991) shallow-water carbonate platforms; symbols are plotted every second point. The oceanic (pelagic) record is shown in gray from Zachos et al. (2001) in each example and has been scaled to the approximate sedimentation rate. The right-hand panel shows data from five Neoproterozoic examples preceding the Marinoan glaciation that have been used to show stratigraphic reproducibility of the carbon isotope excursion, including sections from Namibia and Svalbard representing approximately similar spacing as for the Pliocene–Pleistocene Caribbean sections (between 20 and 60 km). Ombaatjie Formation (black); Fransfontein Ridge (Kennedy et al., 1998) (dark blue); Tweelingskop section at Huab Ridge (green); Keiserfontein section at Makalani Ridge (Halverson et al., 2002) (orange); Sveanor (light blue); Sore Russoya (pink) sections from Svalbard in the Russoya Member of the Elbobreen Formation (Halverson et al., 2004).]()
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1-20 OF 42 RESULTS FOR
Fransfontein Namibia
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1
Image
Fransfontein Ridge (Namibia) geology in the vicinity of sample DW-1. See F...
Published: 01 August 2016
Figure 2. Fransfontein Ridge (Namibia) geology in the vicinity of sample DW-1. See Figure 1 for location. Fm—formation; ls—limestone; ds—dolostone.
Journal Article
The geology of the Neoproterozoic Swakop-Otavi transition zone in the Outjo District, northern Damara Orogen, Namibia
Journal: South African Journal of Geology
Publisher: Geological Society of South Africa
Published: 01 March 2008
South African Journal of Geology (2008) 111 (1): 117–140.
... 2 ). One of the earliest studies of the region was by Stahl (1940) who presented a 1:750 000 scale geological reconnaissance map in colour for northern Namibia, and suggested that the Otavi dolomite sequence of the Fransfontein Ridge is younger than the limestone-shale succession of the Damara...
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Image
(A) North-south stratigraphic cross section and composite carbon isotope re...
in An ice grounding-line wedge from the Ghaub glaciation (635 Ma) on the distal foreslope of the Otavi carbonate platform, Namibia, and its bearing on the snowball Earth hypothesis
> GSA Bulletin
Published: 01 July 2011
B. Tanz.—Tanzania; Zam.—Zambia; Mal.—Malawi; Zim.—Zimbabwe; Nam.—Namibia; Bots.—Botswana; Moz.—Mozambique; Swaz.—Swaziland. (B) Setting of the Kamanjab inlier with Fransfontein homocline on its southern margin (rectangle gives area of Fig. 1C ). Ru—Ruacana; Op—Opuwu; Ka—Kamanjab; Kh—Khorixas; Ou
Image
Composite boron and carbon (B, C) isotope record and paleo-pH reconstructio...
in Neoproterozoic ice ages, boron isotopes, and ocean acidification: Implications for a snowball Earth
> Geology
Published: 01 September 2010
Figure 2. Composite boron and carbon (B, C) isotope record and paleo-pH reconstruction across Neoproterozoic Chuos and Ghaub glacials and subsequent greenhouse transitions on southern Congo craton in northern Namibia. Rasthof cap carbonate of Chuos glacial includes two separate sections
Journal Article
28th DeBeers Alex. Du Toit Memorial Lecture, 2004. On Cryogenian (Neoproterozoic) ice-sheet dynamics and the limitations of the glacial sedimentary record
Journal: South African Journal of Geology
Publisher: Geological Society of South Africa
Published: 01 December 2005
South African Journal of Geology (2005) 108 (4): 557–577.
... with the glacial sedimentary record indicating the former existence of fast-moving wet-base ice and open proglacial waters. The younger Cryogenian glaciation in northern Namibia presents an excellent opportunity to investigate the sedimentary record. The area was then a vast shallow-water carbonate platform...
FIGURES
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Image
Stratigraphic column of investigated sections with corresponding δ 11 B (‰)...
Published: 01 December 2014
, south China. C: Ombaatjie section, Congo craton, Namibia. D: Khowarib section, Congo craton, Namibia. E: Fransfontein section, Congo craton, Namibia. AT—Aktas tillite; NT—Nantuo tillite; GG—Ghaub glacial deposit; KM—Keilberg Member.
Image
Simplified stratigraphy of the Fransfontein Ridge area around Duurwater and...
Published: 01 August 2016
Figure 3. Simplified stratigraphy of the Fransfontein Ridge area around Duurwater and the Navachab area, Namibia (for details of Navachab, see Hoffmann et al., 2004 ); left column is a detailed section showing the stratigraphic position of the DW-1 ash bed, the middle of three ash beds, within
Image
Outcrop belt of the autochthonous Otavi Group in northern Namibia (Hedberg,...
in 28th DeBeers Alex. Du Toit Memorial Lecture, 2004. On Cryogenian (Neoproterozoic) ice-sheet dynamics and the limitations of the glacial sedimentary record
> South African Journal of Geology
Published: 01 December 2005
Figure 7. Outcrop belt of the autochthonous Otavi Group in northern Namibia (Hedberg, 1981), showing approximate trace of the foreslope-platform break (dashed white line). Rectangular box gives location of the Fransfontein Ridge. Towns: Gr, Grootberg; Ka, Kamanjab; Kh, Khorixas; Ko, Kombat; Op
Journal Article
An ice grounding-line wedge from the Ghaub glaciation (635 Ma) on the distal foreslope of the Otavi carbonate platform, Namibia, and its bearing on the snowball Earth hypothesis
Journal: GSA Bulletin
Publisher: Geological Society of America
Published: 01 July 2011
GSA Bulletin (2011) 123 (7-8): 1448–1477.
... B. Tanz.—Tanzania; Zam.—Zambia; Mal.—Malawi; Zim.—Zimbabwe; Nam.—Namibia; Bots.—Botswana; Moz.—Mozambique; Swaz.—Swaziland. (B) Setting of the Kamanjab inlier with Fransfontein homocline on its southern margin (rectangle gives area of Fig. 1C ). Ru—Ruacana; Op—Opuwu; Ka—Kamanjab; Kh—Khorixas; Ou...
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Journal Article
Neoproterozoic ice ages, boron isotopes, and ocean acidification: Implications for a snowball Earth
Journal: Geology
Publisher: Geological Society of America
Published: 01 September 2010
Geology (2010) 38 (9): 775–778.
...Figure 2. Composite boron and carbon (B, C) isotope record and paleo-pH reconstruction across Neoproterozoic Chuos and Ghaub glacials and subsequent greenhouse transitions on southern Congo craton in northern Namibia. Rasthof cap carbonate of Chuos glacial includes two separate sections...
FIGURES
Journal Article
Ocean acidification in the aftermath of the Marinoan glaciation
Journal: Geology
Publisher: Geological Society of America
Published: 01 December 2014
Geology (2014) 42 (12): 1103–1106.
..., south China. C: Ombaatjie section, Congo craton, Namibia. D: Khowarib section, Congo craton, Namibia. E: Fransfontein section, Congo craton, Namibia. AT—Aktas tillite; NT—Nantuo tillite; GG—Ghaub glacial deposit; KM—Keilberg Member. ...
FIGURES
Image
A: Geological sketch of Malyi and Bolshoi Karatau Range (Kazakhstan) displa...
Published: 01 December 2014
Cremonese et al., 2013 ). C: Generalized geological map of northern Namibia showing locations of Fransfontein, Ombaatjie, and Khowarib sections (modified after Kasemann et al., 2010 ).
Journal Article
Duration and nature of the end-Cryogenian (Marinoan) glaciation
Journal: Geology
Publisher: Geological Society of America
Published: 01 August 2016
Geology (2016) 44 (8): 631–634.
...Figure 2. Fransfontein Ridge (Namibia) geology in the vicinity of sample DW-1. See Figure 1 for location. Fm—formation; ls—limestone; ds—dolostone. ...
FIGURES
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Image
(A) Satellite image of outcrop belt of the Fransfontein homocline in north-...
in An ice grounding-line wedge from the Ghaub glaciation (635 Ma) on the distal foreslope of the Otavi carbonate platform, Namibia, and its bearing on the snowball Earth hypothesis
> GSA Bulletin
Published: 01 July 2011
Figure 2. (A) Satellite image of outcrop belt of the Fransfontein homocline in north-central Namibia with locations of sections (see Fig. 1C for location). Locations of low-altitude oblique photos are given as Figures 5–8 and 10 , as indicated. Stratigraphic units: B—basement; R—Rasthof
Image
Figure 1. Carbon isotopic data from preglacial, glacial, and postglacial ca...
in Carbon isotopic composition of Neoproterozoic glacial carbonates as a test of paleoceanographic models for snowball Earth phenomena
> Geology
Published: 01 December 2001
Figure 1. Carbon isotopic data from preglacial, glacial, and postglacial cap carbonate rocks in northeastern Amadeus basin, central Australia (A), southern Congo Craton, Namibia (B and C), and eastern California (D). No time relationship or correlation within or between glacial intervals
Image
A,B: δ 13 C (A) and δ 11 B (B) measured in bulk carbonates from snowball Ea...
in Boron during meteoric diagenesis and its potential implications for Marinoan snowball Earth δ 11 B-pH excursions
> Geology
Published: 01 July 2015
Figure 1. A,B: δ 13 C (A) and δ 11 B (B) measured in bulk carbonates from snowball Earth cap carbonates of Ghaub Formation at Fransfontein in Namibia ( Kasemann et al., 2010 ), for comparison with diagenetically altered upper sequence of Pliocene–Pleistocene Clino core (Grand Bahama Bank, western
Image
Comparisons of the carbon isotopic records of four Pliocene–Pleistocene cor...
in Does the global stratigraphic reproducibility of δ 13 C in Neoproterozoic carbonates require a marine origin? A Pliocene–Pleistocene comparison
> Geology
Published: 01 January 2012
sections from Namibia and Svalbard representing approximately similar spacing as for the Pliocene–Pleistocene Caribbean sections (between 20 and 60 km). Ombaatjie Formation (black); Fransfontein Ridge ( Kennedy et al., 1998 ) (dark blue); Tweelingskop section at Huab Ridge (green); Keiserfontein section
Journal Article
Carbon isotopic composition of Neoproterozoic glacial carbonates as a test of paleoceanographic models for snowball Earth phenomena
Journal: Geology
Publisher: Geological Society of America
Published: 01 December 2001
Geology (2001) 29 (12): 1135–1138.
...Figure 1. Carbon isotopic data from preglacial, glacial, and postglacial cap carbonate rocks in northeastern Amadeus basin, central Australia (A), southern Congo Craton, Namibia (B and C), and eastern California (D). No time relationship or correlation within or between glacial intervals...
FIGURES
Journal Article
Early extensional detachments in a contractional orogen: coherent, map-scale, submarine slides (mass transport complexes) on the outer slope of an Ediacaran collisional foredeep, eastern Kaoko belt, Namibia
Journal: Canadian Journal of Earth Sciences
Publisher: Canadian Science Publishing
Published: 19 January 2016
Canadian Journal of Earth Sciences (2016) 53 (11): 1177–1189.
... . Hoffman, P.F., Bellefroid, E., Hodgin, E.B., Johnson, B.W., Kunzmann, M., Sansjofre, P., et al. 2014. A Cryogenian-early Ediacaran carbonate shelf break dominated by glacial paleotopography, Fransfontein Ridge, Kunene Region, Namibia. Geological Society of America, 2014 Annual Meeting Abstracts, Paper 130...
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Journal Article
Sedimentary depocenters on Snowball Earth: Case studies from the Sturtian Chuos Formation in northern Namibia
Journal: Geosphere
Publisher: Geological Society of America
Published: 01 June 2017
Geosphere (2017) 13 (3): 811–837.
... , Geological map of Namibia, sheet 2014—Fransfontein: Windhoek, Geological Survey of Namibia , scale 1 : 250,000 . Spence , G.H. , Le Heron , D.P. , and Fairchild , I.J. , 2016 , Sedimentological perspectives on climatic, atmospheric and environmental change in the Neoproterozoic Era...
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