Advanced

The Hlagothi Complex: The identification of fragments from a Mesoarchaean large igneous province on the Kaapvaal Craton

Gumsley, A. P. ; de Kock, M. O. ; Rajesh, H. M. ; Knoper, M. W. ; Söderlund, Ulf LU and Ernst, R. E. (2013) In Lithos 174. p.333-348
Abstract
In this paper, we present geochronological, geochemical and palaeomagnetic results from the Hlagothi Complex and a NW-trending dolerite dyke swarm on the southeastern region of the Kaapvaal Craton in northern KwaZulu-Natal, South Africa. The Hlagothi Complex consists of layered sills of meta-peridotite, pyroxenite and gabbro intruding into the Pongola Supergroup. U-Pb baddeleyite ages on the Hlagothi Complex and a NW-trending dyke of 2866 +/- 2 Ma and 2874 +/- 2 Ma, respectively, reveal a ca. 2.87 Ga magmatic event on the southeastern Kaapvaal Craton. The geochemical signature of the Hlagothi Complex recognises two discrete groupings, with a magmatic source that is chemically distinct from those of the older rift-related Nsuze and Dominion... (More)
In this paper, we present geochronological, geochemical and palaeomagnetic results from the Hlagothi Complex and a NW-trending dolerite dyke swarm on the southeastern region of the Kaapvaal Craton in northern KwaZulu-Natal, South Africa. The Hlagothi Complex consists of layered sills of meta-peridotite, pyroxenite and gabbro intruding into the Pongola Supergroup. U-Pb baddeleyite ages on the Hlagothi Complex and a NW-trending dyke of 2866 +/- 2 Ma and 2874 +/- 2 Ma, respectively, reveal a ca. 2.87 Ga magmatic event on the southeastern Kaapvaal Craton. The geochemical signature of the Hlagothi Complex recognises two discrete groupings, with a magmatic source that is chemically distinct from those of the older rift-related Nsuze and Dominion groups. Additional units on the Kaapvaal Craton can be linked with this new 'Hlagothi' event based on spatial and temporal association, and geochemistry: 1) the Thole Complex, 2) parts of the Usushwana Complex, and 3) flood basalts within the Mozaan Group and Central Rand Group. The association between all these units suggests a previously unrecognised large igneous province in the southeastern Kaapvaal Craton. Our palaeomagnetic data identifies a possible primary magnetisation within the least-altered lithologies of the Hlagothi Complex (with a virtual geographic pole at 23.4 degrees N, 53.4 degrees E, dp=8.2 degrees and dm=11.8 degrees). The bulk of samples however, displayed two episodes of remagnetisation. These are likely to be associated with 2.85 to 2.75 Ga aged granitoids across the southeastern Kaapvaal Craton, and tectonic activity in the nearby Meso- to Neoproterozoic Namaqua-Natal mobile belt A short-lived (<= 8 Ma) mantle plume is proposed to have caused the ca. 2.87 Ga magmatism, and also may well have controlled sedimentation within the Pongola-Witwatersrand basin. Volcanism during uplift would have been fed through a series of feeder dykes and sills, of which the Hlagothi Complex and NW-trending dykes are part of. (C) 2012 Elsevier B.V. All rights reserved. (Less)
Please use this url to cite or link to this publication:
author
; ; ; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Hlagothi Complex, Southeastern Kaapvaal Craton, Large igneous province, Magmatic barcode, U-Pb baddeleyite, Archaean paleopole
in
Lithos
volume
174
pages
17 pages
publisher
Elsevier
external identifiers
  • wos:000321680400023
  • scopus:84878909766
ISSN
0024-4937
DOI
10.1016/j.lithos.2012.06.007
language
English
LU publication?
yes
id
16662a94-c679-4582-9e3b-ab1ede0042d0 (old id 3975681)
date added to LUP
2016-04-01 10:58:50
date last changed
2020-09-30 01:50:22
@article{16662a94-c679-4582-9e3b-ab1ede0042d0,
  abstract     = {In this paper, we present geochronological, geochemical and palaeomagnetic results from the Hlagothi Complex and a NW-trending dolerite dyke swarm on the southeastern region of the Kaapvaal Craton in northern KwaZulu-Natal, South Africa. The Hlagothi Complex consists of layered sills of meta-peridotite, pyroxenite and gabbro intruding into the Pongola Supergroup. U-Pb baddeleyite ages on the Hlagothi Complex and a NW-trending dyke of 2866 +/- 2 Ma and 2874 +/- 2 Ma, respectively, reveal a ca. 2.87 Ga magmatic event on the southeastern Kaapvaal Craton. The geochemical signature of the Hlagothi Complex recognises two discrete groupings, with a magmatic source that is chemically distinct from those of the older rift-related Nsuze and Dominion groups. Additional units on the Kaapvaal Craton can be linked with this new 'Hlagothi' event based on spatial and temporal association, and geochemistry: 1) the Thole Complex, 2) parts of the Usushwana Complex, and 3) flood basalts within the Mozaan Group and Central Rand Group. The association between all these units suggests a previously unrecognised large igneous province in the southeastern Kaapvaal Craton. Our palaeomagnetic data identifies a possible primary magnetisation within the least-altered lithologies of the Hlagothi Complex (with a virtual geographic pole at 23.4 degrees N, 53.4 degrees E, dp=8.2 degrees and dm=11.8 degrees). The bulk of samples however, displayed two episodes of remagnetisation. These are likely to be associated with 2.85 to 2.75 Ga aged granitoids across the southeastern Kaapvaal Craton, and tectonic activity in the nearby Meso- to Neoproterozoic Namaqua-Natal mobile belt A short-lived (&lt;= 8 Ma) mantle plume is proposed to have caused the ca. 2.87 Ga magmatism, and also may well have controlled sedimentation within the Pongola-Witwatersrand basin. Volcanism during uplift would have been fed through a series of feeder dykes and sills, of which the Hlagothi Complex and NW-trending dykes are part of. (C) 2012 Elsevier B.V. All rights reserved.},
  author       = {Gumsley, A. P. and de Kock, M. O. and Rajesh, H. M. and Knoper, M. W. and Söderlund, Ulf and Ernst, R. E.},
  issn         = {0024-4937},
  language     = {eng},
  pages        = {333--348},
  publisher    = {Elsevier},
  series       = {Lithos},
  title        = {The Hlagothi Complex: The identification of fragments from a Mesoarchaean large igneous province on the Kaapvaal Craton},
  url          = {http://dx.doi.org/10.1016/j.lithos.2012.06.007},
  doi          = {10.1016/j.lithos.2012.06.007},
  volume       = {174},
  year         = {2013},
}