Cr isotopic composition of the Laobao cherts during the Ediacaran–Cambrian transition in South China

Cr isotopic composition of the Laobao cherts during the Ediacaran–Cambrian transition in South... In this study, we present the Cr isotopic compositions from the cherts in the Laobao Formation (~551–522 Ma) that were deposited in deep water in South China. The Cr concentrations and isotopic compositions in the Laobao cherts were dominated by the contemporaneous seawater and detrital phases. The lower part of the Laobao cherts show that the δ53Cr of contemporaneous deep seawater in the Huanan basin was approximately −0.1‰, and the δ53Cr of detrital materials was approximately ≥0.2‰. These findings imply that surface 53Cr-enriched Cr(VI) species did not affect the deep ocean until the late Ediacaran because of the strong redox stratification in the ocean, although the oxidative Cr cycle in terrestrial settings had emerged before that time. A slight rise in δ53Cr in the deep ocean (to approximately 0.08‰) was estimated for the upper part of the Laobao cherts. If the δ53Cr rise and its amplitude can be further determined, this will imply that shallow 53Cr-enriched Cr(VI) species had an impact on the deep ocean and will suggest an oxidation of the ocean in the Huanan basin around the Ediacaran–Cambrian boundary (~542 Ma). http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Chemical Geology Elsevier

Cr isotopic composition of the Laobao cherts during the Ediacaran–Cambrian transition in South China

Loading next page...
 
/lp/elsevier/cr-isotopic-composition-of-the-laobao-cherts-during-the-ediacaran-RU5FqJwalv
Publisher
Elsevier
Copyright
Copyright © 2018 Elsevier B.V.
ISSN
0009-2541
eISSN
1872-6836
D.O.I.
10.1016/j.chemgeo.2018.02.011
Publisher site
See Article on Publisher Site

Abstract

In this study, we present the Cr isotopic compositions from the cherts in the Laobao Formation (~551–522 Ma) that were deposited in deep water in South China. The Cr concentrations and isotopic compositions in the Laobao cherts were dominated by the contemporaneous seawater and detrital phases. The lower part of the Laobao cherts show that the δ53Cr of contemporaneous deep seawater in the Huanan basin was approximately −0.1‰, and the δ53Cr of detrital materials was approximately ≥0.2‰. These findings imply that surface 53Cr-enriched Cr(VI) species did not affect the deep ocean until the late Ediacaran because of the strong redox stratification in the ocean, although the oxidative Cr cycle in terrestrial settings had emerged before that time. A slight rise in δ53Cr in the deep ocean (to approximately 0.08‰) was estimated for the upper part of the Laobao cherts. If the δ53Cr rise and its amplitude can be further determined, this will imply that shallow 53Cr-enriched Cr(VI) species had an impact on the deep ocean and will suggest an oxidation of the ocean in the Huanan basin around the Ediacaran–Cambrian boundary (~542 Ma).

Journal

Chemical GeologyElsevier

Published: Apr 5, 2018

References

You’re reading a free preview. Subscribe to read the entire article.


DeepDyve is your
personal research library

It’s your single place to instantly
discover and read the research
that matters to you.

Enjoy affordable access to
over 18 million articles from more than
15,000 peer-reviewed journals.

All for just $49/month

Explore the DeepDyve Library

Search

Query the DeepDyve database, plus search all of PubMed and Google Scholar seamlessly

Organize

Save any article or search result from DeepDyve, PubMed, and Google Scholar... all in one place.

Access

Get unlimited, online access to over 18 million full-text articles from more than 15,000 scientific journals.

Your journals are on DeepDyve

Read from thousands of the leading scholarly journals from SpringerNature, Elsevier, Wiley-Blackwell, Oxford University Press and more.

All the latest content is available, no embargo periods.

See the journals in your area

DeepDyve

Freelancer

DeepDyve

Pro

Price

FREE

$49/month
$360/year

Save searches from
Google Scholar,
PubMed

Create lists to
organize your research

Export lists, citations

Read DeepDyve articles

Abstract access only

Unlimited access to over
18 million full-text articles

Print

20 pages / month

PDF Discount

20% off