Baddeleyite geochronology and geochemistry of mafic cobbles from the Dwyka diamictite: New insights into the sub-Kalahari basement, South Africa
(2011) In Lithos 126(3-4). p.307-320- Abstract
- U-Pb baddeleyite geochronology and geochemistry of mafic cobbles from the similar to 300 Ma Dwyka diamictite on the western boundary of the Kalahari Basin provide new insights into the sub-Kalahari basement. Palaeo-ice flow directions indicate that the origin of the Dwyka diamictite deposits on the border between South Africa and Namibia is from beneath the Kalahari sands to the east or north-east. This work shows that the mafic cobbles from three localities near Rietfontein come from intrusions related to the Umkondo Large Igneous Province (LIP), located in the Kheis or Rehoboth Provinces. The lack of Banded Iron Formation (BIF) cobbles in these glacial diamictites indicates that their source region lies west or north of the BIF-dominated... (More)
- U-Pb baddeleyite geochronology and geochemistry of mafic cobbles from the similar to 300 Ma Dwyka diamictite on the western boundary of the Kalahari Basin provide new insights into the sub-Kalahari basement. Palaeo-ice flow directions indicate that the origin of the Dwyka diamictite deposits on the border between South Africa and Namibia is from beneath the Kalahari sands to the east or north-east. This work shows that the mafic cobbles from three localities near Rietfontein come from intrusions related to the Umkondo Large Igneous Province (LIP), located in the Kheis or Rehoboth Provinces. The lack of Banded Iron Formation (BIF) cobbles in these glacial diamictites indicates that their source region lies west or north of the BIF-dominated Griqualand West Basin of the Kaapvaal Craton. The four dated mafic cobbles give U-Pb ages of 1111-1123 Ma, coeval with dolerites of the Umkondo LIP. The cobbles experienced greenschist fades metamorphism before the Dwyka glaciation, but are unfoliated. The geochemistry of the cobbles indicates that they are genetically similar and have a within-plate setting. They show many similarities to the Umkondo LIP dolerites and the coeval Rouxville Formation, an upper unit of the Koras Group. The most likely sources of the cobbles are the mafic intrusives and lavas along the Kalahari Line, southern equivalents of the similar to 1.11 Ga Tshane and Xade complexes or intrusive and extrusive mafic units related to the Umkondo LIP, now concealed beneath the Kalahari sands. (C) 2011 Elsevier By. All rights reserved. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/2253157
- author
- van Schijndel, Valby ; Cornell, David H. ; Karlsson, Linn and Olsson, Johan LU
- organization
- publishing date
- 2011
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- Dwyka diamictite, U-Pb baddeleyite geochronology, Geochemistry, Umkondo, LIP, Koras group
- in
- Lithos
- volume
- 126
- issue
- 3-4
- pages
- 307 - 320
- publisher
- Elsevier
- external identifiers
-
- wos:000296822900013
- scopus:80052026853
- ISSN
- 0024-4937
- DOI
- 10.1016/j.lithos.2011.07.019
- language
- English
- LU publication?
- yes
- id
- a405e723-6f74-4c6b-812b-01c0f4f4223f (old id 2253157)
- date added to LUP
- 2016-04-01 10:14:12
- date last changed
- 2022-01-25 21:11:05
@article{a405e723-6f74-4c6b-812b-01c0f4f4223f,
abstract = {{U-Pb baddeleyite geochronology and geochemistry of mafic cobbles from the similar to 300 Ma Dwyka diamictite on the western boundary of the Kalahari Basin provide new insights into the sub-Kalahari basement. Palaeo-ice flow directions indicate that the origin of the Dwyka diamictite deposits on the border between South Africa and Namibia is from beneath the Kalahari sands to the east or north-east. This work shows that the mafic cobbles from three localities near Rietfontein come from intrusions related to the Umkondo Large Igneous Province (LIP), located in the Kheis or Rehoboth Provinces. The lack of Banded Iron Formation (BIF) cobbles in these glacial diamictites indicates that their source region lies west or north of the BIF-dominated Griqualand West Basin of the Kaapvaal Craton. The four dated mafic cobbles give U-Pb ages of 1111-1123 Ma, coeval with dolerites of the Umkondo LIP. The cobbles experienced greenschist fades metamorphism before the Dwyka glaciation, but are unfoliated. The geochemistry of the cobbles indicates that they are genetically similar and have a within-plate setting. They show many similarities to the Umkondo LIP dolerites and the coeval Rouxville Formation, an upper unit of the Koras Group. The most likely sources of the cobbles are the mafic intrusives and lavas along the Kalahari Line, southern equivalents of the similar to 1.11 Ga Tshane and Xade complexes or intrusive and extrusive mafic units related to the Umkondo LIP, now concealed beneath the Kalahari sands. (C) 2011 Elsevier By. All rights reserved.}},
author = {{van Schijndel, Valby and Cornell, David H. and Karlsson, Linn and Olsson, Johan}},
issn = {{0024-4937}},
keywords = {{Dwyka diamictite; U-Pb baddeleyite geochronology; Geochemistry; Umkondo; LIP; Koras group}},
language = {{eng}},
number = {{3-4}},
pages = {{307--320}},
publisher = {{Elsevier}},
series = {{Lithos}},
title = {{Baddeleyite geochronology and geochemistry of mafic cobbles from the Dwyka diamictite: New insights into the sub-Kalahari basement, South Africa}},
url = {{http://dx.doi.org/10.1016/j.lithos.2011.07.019}},
doi = {{10.1016/j.lithos.2011.07.019}},
volume = {{126}},
year = {{2011}},
}