Editing Permian–Triassic extinction event (section)

====Indochina–South China subduction-zone volcanic arc====
Mercury anomalies preceding the end-Permian extinction have been discovered in what was then the boundary between the South China craton and the Indochinese plate, a subduction zone with a volcanic arc. Hafnium isotopes from syndepositional magmatic zircons found in ash beds created by this volcanic pulse confirm its origin in subduction-zone volcanism rather than large igneous province activity.<ref name="MercuryFluxesRegionalVolcanismSouthChinaCraton" /> The enrichment of copper samples from these deposits in isotopically light copper provide additional confirmation.<ref>{{cite journal |last1=Zhang |first1=Hua |last2=Zhang |first2=Feifei |last3=Chen |first3=Jiubin |last4=Erwin |first4=Douglas H. |last5=Syverson |first5=Drew D. |last6=Ni |first6=Pei |last7=Rampino |first7=Michael R. |last8=Chi |first8=Zhe |last9=Cai |first9=Yao-Feng |last10=Xiang |first10=Lei |last11=Li |first11=We-Qiang |last12=Liu |first12=Sheng-Ao |last13=Wang |first13=Ru-Cheng |last14=Wang |first14=Xiang-Dong |last15=Feng |first15=Zhuo |last16=Li |first16=Hou-Min |last17=Zhang |first17=Ting |last18=Cai |first18=Mong-Ming |last19=Zheng |first19=Wang |last20=Cui |first20=Ying |last21=Zhu |first21=Xiang-Kun |last22=Hou |first22=Zeng-Qian |last23=Wu |first23=Fu-Yuan |last24=Xu |first24=Yi-Gang |last25=Planavsky |first25=Noah J. |last26=Shen |first26=Shu-zhong |date=17 November 2021 |title=Felsic volcanism as a factor driving the end-Permian mass extinction |journal=[[Science Advances]] |volume=7 |issue=47 |pages=eabh1390 |doi=10.1126/sciadv.abh1390 |pmid=34788084 |pmc=8597993 |bibcode=2021SciA....7.1390Z }}</ref> This volcanism has been speculated to have caused local biotic stress among radiolarians, sponges, and brachiopods over the 60,000 years preceding the end-Permian marine extinction, as well as an ammonoid crisis with decreased morphological complexity and size and increased rate of turnover beginning in the lower ''C. yini'' biozone, around 200,000 years before the extinction.<ref name="MercuryFluxesRegionalVolcanismSouthChinaCraton">{{cite journal |last1=Shen |first1=Jun |last2=Chen |first2=Jiubin |last3=Algeo |first3=Thomas J. |last4=Feng |first4=Qinglai |last5=Yu |first5=Jianxin |last6=Xu |first6=Yi-Gang |last7=Xu |first7=Guozhen |last8=Lei |first8=Yong |last9=Planavsky |first9=Noah J. |last10=Xie |first10=Shucheng |date=10 December 2020 |title=Mercury fluxes record regional volcanism in the South China craton prior to the end-Permian mass extinction |url=https://pubs.geoscienceworld.org/gsa/geology/article-abstract/49/4/452/593185/Mercury-fluxes-record-regional-volcanism-in-the?redirectedFrom=fulltext |journal=[[Geology (journal)|Geology]] |volume=49 |issue=4 |pages=452–456 |doi=10.1130/G48501.1 |s2cid=230524628 |access-date=28 March 2023|url-access=subscription }}</ref>