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Zinc isotope evidence for intensive magmatism immediately before the end-Permian mass extinction
- Source :
- Geology. 45:343-346
- Publication Year :
- 2017
- Publisher :
- Geological Society of America, 2017.
-
Abstract
- The end-Permian extinction is typically ascribed to massive volcanic eruptions, but direct geochemical evidence linking the two independent events is generally lacking. Zinc is an important micronutrient of marine phytoplanktons, and Zn isotope (δ66Zn) ratios of seawater are markedly higher than those of volcanic rocks and riverine waters. We conducted high-resolution Zn concentration and Zn isotope analyses on carbonate rocks across the Permian-Triassic boundary (PTB) in the Meishan section of south China. An abrupt increase of Zn concentration and a concomitant 0.5‰ decrease in δ66Zn occur ∼35 k.y. before the mass extinction and carbon isotope (δ13C) minima. Mass balance calculation demonstrates that a 0.5‰ negative shift in δ66Zn within thousands of years requires rapid and massive input of isotopically light Zn from volcanic ashes, hydrothermal inputs, and/or extremely fast weathering of large igneous provinces. A positive δ66Zn shift of as much as 1.0‰ following the mass extinction demonstrates that primary productivity recovered and reached a maximum in fewer than 360 k.y. Our finding provides insights into the marine Zn cycling across the PTB and clarifies the temporal relationship and duration of events, including intensive volcanism, carbon isotope excursion, mass extinction, and widespread ocean anoxia.
- Subjects :
- Extinction event
geography
Extinction
geography.geographical_feature_category
010504 meteorology & atmospheric sciences
Geochemistry
Geology
010502 geochemistry & geophysics
01 natural sciences
Volcanic rock
Igneous rock
Paleontology
Volcano
Isotopes of carbon
Carbonate rock
Permian–Triassic extinction event
0105 earth and related environmental sciences
Subjects
Details
- ISSN :
- 19432682 and 00917613
- Volume :
- 45
- Database :
- OpenAIRE
- Journal :
- Geology
- Accession number :
- edsair.doi...........41f9ffeec07fff36fd50a2db8bd22436