Universität zu Köln

Wotte, Thomas and Strauss, Harald (2015). Questioning a widespread euxinia for the Furongian (Late Cambrian) SPICE event: indications from delta C-13, delta O-18, delta S-34 and biostratigraphic constraints. Geol. Mag., 152 (6). S. 1085 - 1104. NEW YORK: CAMBRIDGE UNIV PRESS. ISSN 1469-5081

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Abstract

Results from a high-resolution study of delta C-13(carb), delta O-18(carb), delta S-34(CAS), delta S-34(CRS) and elemental concentrations (Ca, Fe, Mg, Mn and Sr) in the Furongian Kyrshabakty section, southern Kazakhstan, are reported here. The investigated interval covers the Drumian to Jiangshanian stages of the Cambrian Period, respectively the regional Ptychagnostus atavus to Ivshinagnostus ivshini-Irvingella major trilobite zones. delta C-13(carb) data include the Steptoean positive carbon isotope excursion (SPICE) with a local peak value of + 5 parts per thousand. The onset of SPICE corresponds to the Kormagnostus simplex Glyptagnostus stolidotus zones and pre-dates the base of the Paibian Stage/Furongian Series. delta S-34(CAS) data already increase during the Lejopyge armata biozone culminating in three positive excursions prior and after the SPICE maximum. Differences in onset, peak values and shape of the delta C-13(carb) and/or delta S-34(CAS) excursions at Kyrshabakty, but also in almost all sections characterized by the SPICE, are pointing towards Furongian seawater that was low in sulphate concentration and heterogeneous in its carbonate carbon and sulphate sulphur isotopic composition. The occurrence of benthic faunal elements in almost all SPICE-related sections strongly supports oxygenated conditions at the seafloor, therefore excluding widespread anoxia or euxinia. Regional anoxic conditions are most probable. A positive delta O-18(carb) excursion parallel to the SPICE could probably be explained by a decline in seawater pH associated with a sea-level rise. Again, no euxinic conditions would be mandatory for explaining the SPICE event.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Wotte, Thomas UNSPECIFIED UNSPECIFIED UNSPECIFIED Strauss, Harald UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-385970
DOI:	10.1017/S0016756815000187
Journal or Publication Title:	Geol. Mag.
Volume:	152
Number:	6
Page Range:	S. 1085 - 1104
Date:	2015
Publisher:	CAMBRIDGE UNIV PRESS
Place of Publication:	NEW YORK
ISSN:	1469-5081
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language CARBON-ISOTOPE EXCURSION; ARGENTINE PRECORDILLERA; MONTAGNE-NOIRE; C-ISOTOPE; SEAWATER; SULFUR; OXYGEN; ORDOVICIAN; EVOLUTION; SULFATE Multiple languages Geosciences, Multidisciplinary Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/38597