Petrogenesis and provenance of distal volcanic tuffs from the Permian–Triassic Karoo Basin, South Africa: A window into a dissected magmatic province
We present zircon rare earth element (REE) compositions integrated with U-Pb ages of zircon and whole-rock geochemistry from 29 volcanic tuffs preserved in the Karoo Supergroup, South Africa, to investigate the history of magmatism in southern Gondwana. Whole-rock compositions suggest a subduction-d...
Published in: | Geosphere |
---|---|
Main Authors: | , , , , |
Format: | Text |
Language: | unknown |
Published: |
BearWorks
2016
|
Subjects: | |
Online Access: | https://bearworks.missouristate.edu/articles-cnas/599 https://bearworks.missouristate.edu/cgi/viewcontent.cgi?article=1598&context=articles-cnas |
id |
ftmissouristuniv:oai:bearworks.missouristate.edu:articles-cnas-1598 |
---|---|
record_format |
openpolar |
spelling |
ftmissouristuniv:oai:bearworks.missouristate.edu:articles-cnas-1598 2023-05-15T13:52:44+02:00 Petrogenesis and provenance of distal volcanic tuffs from the Permian–Triassic Karoo Basin, South Africa: A window into a dissected magmatic province McKay, Matthew P. Coble, Matthew A. Hessler, Angela M. Weislogel, Amy L. Fildani, Andrea 2016-01-01T08:00:00Z application/pdf https://bearworks.missouristate.edu/articles-cnas/599 https://bearworks.missouristate.edu/cgi/viewcontent.cgi?article=1598&context=articles-cnas unknown BearWorks https://bearworks.missouristate.edu/articles-cnas/599 https://bearworks.missouristate.edu/cgi/viewcontent.cgi?article=1598&context=articles-cnas College of Natural and Applied Sciences text 2016 ftmissouristuniv 2022-02-28T19:49:46Z We present zircon rare earth element (REE) compositions integrated with U-Pb ages of zircon and whole-rock geochemistry from 29 volcanic tuffs preserved in the Karoo Supergroup, South Africa, to investigate the history of magmatism in southern Gondwana. Whole-rock compositions suggest a subduction-driven magmatic arc source for early (before 270 Ma) to middle Permian (270-260 Ma) Karoo tuffs. After ca. 265 Ma, the magmatic source of the volcanic deposits transitioned toward intraplate shallow-sourced magmatism. Zircon U-Pb ages and REE chemistry suggest that early to middle Permian magmas were oxidizing, U- and heavy (H) REE-enriched, melts; middle Permian to Triassic zircons record HREE-depleted, more reduced magmatism. Middle Permian to Triassic tuffs contain increasingly large volumes of zircon cargo derived from assimilated crustal material; therefore magmas may have been zircon undersaturated, resulting in less zircon growth and increased inheritance in late Permian to Triassic Gondwanan volcanics. Zircon U-Pb ages and zircon REE chemistry suggest a shift from arc magmatism in the early Permian to extensional magmatism by the late Permian, which may be associated with development of a backarc magmatic system adjacent to western Antarctica that predates known extensional volcanism elsewhere in Gondwana. Opening of the Southern Ocean in the Jurassic-Cretaceous paralleled this extensional feature, which may be related to reactivation of this Permian-Triassic backarc. This study demonstrates the potential of zircon U-Pb age and REE compositions from volcanic tuffs preserved in sedimentary strata to provide a more complete record of magmatism, when the magmatic province has been largely lost to active tectonism. Text Antarc* Antarctica Southern Ocean Missouri State University: BearWorks Southern Ocean Geosphere 12 1 1 14 |
institution |
Open Polar |
collection |
Missouri State University: BearWorks |
op_collection_id |
ftmissouristuniv |
language |
unknown |
description |
We present zircon rare earth element (REE) compositions integrated with U-Pb ages of zircon and whole-rock geochemistry from 29 volcanic tuffs preserved in the Karoo Supergroup, South Africa, to investigate the history of magmatism in southern Gondwana. Whole-rock compositions suggest a subduction-driven magmatic arc source for early (before 270 Ma) to middle Permian (270-260 Ma) Karoo tuffs. After ca. 265 Ma, the magmatic source of the volcanic deposits transitioned toward intraplate shallow-sourced magmatism. Zircon U-Pb ages and REE chemistry suggest that early to middle Permian magmas were oxidizing, U- and heavy (H) REE-enriched, melts; middle Permian to Triassic zircons record HREE-depleted, more reduced magmatism. Middle Permian to Triassic tuffs contain increasingly large volumes of zircon cargo derived from assimilated crustal material; therefore magmas may have been zircon undersaturated, resulting in less zircon growth and increased inheritance in late Permian to Triassic Gondwanan volcanics. Zircon U-Pb ages and zircon REE chemistry suggest a shift from arc magmatism in the early Permian to extensional magmatism by the late Permian, which may be associated with development of a backarc magmatic system adjacent to western Antarctica that predates known extensional volcanism elsewhere in Gondwana. Opening of the Southern Ocean in the Jurassic-Cretaceous paralleled this extensional feature, which may be related to reactivation of this Permian-Triassic backarc. This study demonstrates the potential of zircon U-Pb age and REE compositions from volcanic tuffs preserved in sedimentary strata to provide a more complete record of magmatism, when the magmatic province has been largely lost to active tectonism. |
format |
Text |
author |
McKay, Matthew P. Coble, Matthew A. Hessler, Angela M. Weislogel, Amy L. Fildani, Andrea |
spellingShingle |
McKay, Matthew P. Coble, Matthew A. Hessler, Angela M. Weislogel, Amy L. Fildani, Andrea Petrogenesis and provenance of distal volcanic tuffs from the Permian–Triassic Karoo Basin, South Africa: A window into a dissected magmatic province |
author_facet |
McKay, Matthew P. Coble, Matthew A. Hessler, Angela M. Weislogel, Amy L. Fildani, Andrea |
author_sort |
McKay, Matthew P. |
title |
Petrogenesis and provenance of distal volcanic tuffs from the Permian–Triassic Karoo Basin, South Africa: A window into a dissected magmatic province |
title_short |
Petrogenesis and provenance of distal volcanic tuffs from the Permian–Triassic Karoo Basin, South Africa: A window into a dissected magmatic province |
title_full |
Petrogenesis and provenance of distal volcanic tuffs from the Permian–Triassic Karoo Basin, South Africa: A window into a dissected magmatic province |
title_fullStr |
Petrogenesis and provenance of distal volcanic tuffs from the Permian–Triassic Karoo Basin, South Africa: A window into a dissected magmatic province |
title_full_unstemmed |
Petrogenesis and provenance of distal volcanic tuffs from the Permian–Triassic Karoo Basin, South Africa: A window into a dissected magmatic province |
title_sort |
petrogenesis and provenance of distal volcanic tuffs from the permian–triassic karoo basin, south africa: a window into a dissected magmatic province |
publisher |
BearWorks |
publishDate |
2016 |
url |
https://bearworks.missouristate.edu/articles-cnas/599 https://bearworks.missouristate.edu/cgi/viewcontent.cgi?article=1598&context=articles-cnas |
geographic |
Southern Ocean |
geographic_facet |
Southern Ocean |
genre |
Antarc* Antarctica Southern Ocean |
genre_facet |
Antarc* Antarctica Southern Ocean |
op_source |
College of Natural and Applied Sciences |
op_relation |
https://bearworks.missouristate.edu/articles-cnas/599 https://bearworks.missouristate.edu/cgi/viewcontent.cgi?article=1598&context=articles-cnas |
container_title |
Geosphere |
container_volume |
12 |
container_issue |
1 |
container_start_page |
1 |
op_container_end_page |
14 |
_version_ |
1766257199704702976 |