Convergent continental margin volcanic source for ash beds at the Permian-Triassic boundary, South China: Constraints from trace elements and Hf-isotopes

Xiangdong Wang, Peter A. Cawood, Laishi Zhao, Zhong Qiang Chen, Zhengyi Lyu, Biao Ma

Research output: Contribution to journalArticleResearchpeer-review

Abstract

Volcanic activity around the time of the Permian-Triassic boundary (PTB) has been proposed as a trigger for the associated biocrisis. Multiple claystone beds are prominent near the PTB sections in South China. Twenty one PTB ash beds from three sections at Shangsi, Jianshi and Meishan in South China were sampled and analyzed. Volcanic ash geochemistry indicate dacite and rhyolite compositions. Zircons from the ash layers yield comparatively low Nb/Hf and high Th/Nb ratios, falling in the range of arc/orogenic-related settings. Zircon Hf-isotope compositions show that ε Hf (t) values vary from −11.7 to 1.8, indicating involvement of both juvenile and ancient crustal components. The ash beds (SS27a, JS129, JS130, JS133,MS25, MS26) near the biotic extinction horizon display a large variation in ε Hf (t) and relatively positive average values, indicating input of juvenile mantle or crust, and implying rapid transit through the older basement of the South China Craton. Spatial and temporal distribution of ash beds from thirty one PTB sections worldwide reveal that volcanic ash beds occur mainly in, or proximal to, the Tethys region and were sourced locally. Integration of Hf-isotope and trace-element compositions from magmatic zircons suggests that the PTB volcanism occurred along the convergent continent margin in, or near, southwestern South China as a result of the closure of the Paleo-Tethys Ocean.

Original languageEnglish
Pages (from-to)154-165
Number of pages12
JournalPalaeogeography, Palaeoclimatology, Palaeoecology
Volume519
DOIs
Publication statusPublished - 1 Apr 2019

Keywords

  • Triassic
  • Hindeodus parvus
  • Permian

Cite this

@article{f178d6b2f4644fbeb988122451fca6ea,
title = "Convergent continental margin volcanic source for ash beds at the Permian-Triassic boundary, South China: Constraints from trace elements and Hf-isotopes",
abstract = "Volcanic activity around the time of the Permian-Triassic boundary (PTB) has been proposed as a trigger for the associated biocrisis. Multiple claystone beds are prominent near the PTB sections in South China. Twenty one PTB ash beds from three sections at Shangsi, Jianshi and Meishan in South China were sampled and analyzed. Volcanic ash geochemistry indicate dacite and rhyolite compositions. Zircons from the ash layers yield comparatively low Nb/Hf and high Th/Nb ratios, falling in the range of arc/orogenic-related settings. Zircon Hf-isotope compositions show that ε Hf (t) values vary from −11.7 to 1.8, indicating involvement of both juvenile and ancient crustal components. The ash beds (SS27a, JS129, JS130, JS133,MS25, MS26) near the biotic extinction horizon display a large variation in ε Hf (t) and relatively positive average values, indicating input of juvenile mantle or crust, and implying rapid transit through the older basement of the South China Craton. Spatial and temporal distribution of ash beds from thirty one PTB sections worldwide reveal that volcanic ash beds occur mainly in, or proximal to, the Tethys region and were sourced locally. Integration of Hf-isotope and trace-element compositions from magmatic zircons suggests that the PTB volcanism occurred along the convergent continent margin in, or near, southwestern South China as a result of the closure of the Paleo-Tethys Ocean.",
keywords = "Triassic, Hindeodus parvus, Permian",
author = "Xiangdong Wang and Cawood, {Peter A.} and Laishi Zhao and Chen, {Zhong Qiang} and Zhengyi Lyu and Biao Ma",
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doi = "10.1016/j.palaeo.2018.02.011",
language = "English",
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journal = "Palaeogeography, Palaeoclimatology, Palaeoecology",
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Convergent continental margin volcanic source for ash beds at the Permian-Triassic boundary, South China : Constraints from trace elements and Hf-isotopes. / Wang, Xiangdong; Cawood, Peter A.; Zhao, Laishi; Chen, Zhong Qiang; Lyu, Zhengyi; Ma, Biao.

In: Palaeogeography, Palaeoclimatology, Palaeoecology, Vol. 519, 01.04.2019, p. 154-165.

Research output: Contribution to journalArticleResearchpeer-review

TY - JOUR

T1 - Convergent continental margin volcanic source for ash beds at the Permian-Triassic boundary, South China

T2 - Constraints from trace elements and Hf-isotopes

AU - Wang, Xiangdong

AU - Cawood, Peter A.

AU - Zhao, Laishi

AU - Chen, Zhong Qiang

AU - Lyu, Zhengyi

AU - Ma, Biao

PY - 2019/4/1

Y1 - 2019/4/1

N2 - Volcanic activity around the time of the Permian-Triassic boundary (PTB) has been proposed as a trigger for the associated biocrisis. Multiple claystone beds are prominent near the PTB sections in South China. Twenty one PTB ash beds from three sections at Shangsi, Jianshi and Meishan in South China were sampled and analyzed. Volcanic ash geochemistry indicate dacite and rhyolite compositions. Zircons from the ash layers yield comparatively low Nb/Hf and high Th/Nb ratios, falling in the range of arc/orogenic-related settings. Zircon Hf-isotope compositions show that ε Hf (t) values vary from −11.7 to 1.8, indicating involvement of both juvenile and ancient crustal components. The ash beds (SS27a, JS129, JS130, JS133,MS25, MS26) near the biotic extinction horizon display a large variation in ε Hf (t) and relatively positive average values, indicating input of juvenile mantle or crust, and implying rapid transit through the older basement of the South China Craton. Spatial and temporal distribution of ash beds from thirty one PTB sections worldwide reveal that volcanic ash beds occur mainly in, or proximal to, the Tethys region and were sourced locally. Integration of Hf-isotope and trace-element compositions from magmatic zircons suggests that the PTB volcanism occurred along the convergent continent margin in, or near, southwestern South China as a result of the closure of the Paleo-Tethys Ocean.

AB - Volcanic activity around the time of the Permian-Triassic boundary (PTB) has been proposed as a trigger for the associated biocrisis. Multiple claystone beds are prominent near the PTB sections in South China. Twenty one PTB ash beds from three sections at Shangsi, Jianshi and Meishan in South China were sampled and analyzed. Volcanic ash geochemistry indicate dacite and rhyolite compositions. Zircons from the ash layers yield comparatively low Nb/Hf and high Th/Nb ratios, falling in the range of arc/orogenic-related settings. Zircon Hf-isotope compositions show that ε Hf (t) values vary from −11.7 to 1.8, indicating involvement of both juvenile and ancient crustal components. The ash beds (SS27a, JS129, JS130, JS133,MS25, MS26) near the biotic extinction horizon display a large variation in ε Hf (t) and relatively positive average values, indicating input of juvenile mantle or crust, and implying rapid transit through the older basement of the South China Craton. Spatial and temporal distribution of ash beds from thirty one PTB sections worldwide reveal that volcanic ash beds occur mainly in, or proximal to, the Tethys region and were sourced locally. Integration of Hf-isotope and trace-element compositions from magmatic zircons suggests that the PTB volcanism occurred along the convergent continent margin in, or near, southwestern South China as a result of the closure of the Paleo-Tethys Ocean.

KW - Triassic

KW - Hindeodus parvus

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U2 - 10.1016/j.palaeo.2018.02.011

DO - 10.1016/j.palaeo.2018.02.011

M3 - Article

VL - 519

SP - 154

EP - 165

JO - Palaeogeography, Palaeoclimatology, Palaeoecology

JF - Palaeogeography, Palaeoclimatology, Palaeoecology

SN - 0031-0182

ER -