Carbon, sulfur, oxygen and strontium isotope records, organic geochemistry and biostratigraphy across the Permian/Triassic boundary in Abadeh, Iran

Joachimski M (2004)

Publication Type: Journal article

Publication year: 2004

Journal

International Journal of Earth Sciences Springer Verlag (Germany)

Publisher: Springer Verlag (Germany)

Pages Range: 26-45

Journal Issue: 93

DOI: 10.1007/s00531-004-0406-7

Abstract

Pelagic deposits at Abadeh represent a complete biostratigraphic record across the Permian/Triassic boundary (PTB). The presumed water depth during deposition of these sediments was between 60 and 90 m. Similar to other Permian/Triassic boundary sections, the succession at Abadeh is characterised by a negative carbon isotope shift of approximately 4‰. The values start to decrease in the lower C. changxingensis - C. deflecta s.l. Zone, reach -0.12‰ (V-PDB) in the uppermost Permian just below the PTB, remain low to the early I. isarcica Zone (-0.32‰) and increase subsequently in the upper I. isarcica Zone. For the time interval of the PTB negative carbon isotope excursion, between the C. iranica and the I. isarcica Zones, no correlation exists between the δ13^{Ccarb δ¹⁸Ocarb. The above observations argue against the conclusion of Heydari et al. (2001) that the carbon isotope event at the P/T transition is an alteration artefact and not a global signal. The decrease in δ¹³Ccarb is accompanied by a ∼5‰ (and potentially up to 10‰) increase in δ³⁴SSSS. Together, these features are thought to reflect a complex global event, notably the development of widespread anoxic oceans with anoxic bottom layers rising onto the shelves. For the carbon isotope drop, other factors, such as the collapse of ocean primary productivity may also have played a role. The ⁸⁷Sr/⁸⁶Sr ratios of Dzhulfian seawater show only a minor increase from 0.70705 to 0.70710, reaching 0.70720 in the Dorashamian. The increase becomes steeper in the Early Triassic reaching 0.70754 in the N. dieneri Zone. The rise of the strontium isotope values is thought to be related to enhanced continental weathering under humid climatic conditions in the uppermost Permian (C. meishanensis - H. praeparvus one) and the lack of a dense land vegetation in the Early Triassic, prior to the Spathian (Upper Olenekian). © Springer-Verlag 2004.}

Authors with CRIS profile

Michael Joachimski Lehrstuhl für Geologie (Exogene Dynamik)

How to cite

APA:

Joachimski, M. (2004). Carbon, sulfur, oxygen and strontium isotope records, organic geochemistry and biostratigraphy across the Permian/Triassic boundary in Abadeh, Iran. International Journal of Earth Sciences, 93, 26-45. https://dx.doi.org/10.1007/s00531-004-0406-7

MLA:

Joachimski, Michael. "Carbon, sulfur, oxygen and strontium isotope records, organic geochemistry and biostratigraphy across the Permian/Triassic boundary in Abadeh, Iran." International Journal of Earth Sciences 93 (2004): 26-45.

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