E-resources
Peer reviewed
Open access
-
Zhang, Qinghai; Ding, Lin; Chen, Xinming; Brennecka, Gregory A.; Sun, Yali; Ma, Xuesong; Gao, Bintao; Zhang, Qian; Willems, Helmut
Earth and planetary science letters, 06/2023, Volume: 612, Issue: naJournal Article
Uranium isotope compositions (δ238) and Th/U in carbonates are being explored as paleoredox proxies to study global oceanic anoxia. However, the impact of changes to local depositional environments that might cause a decline in δ238U and an increase in Th/U has not been thoroughly investigated. Here we report a decline in δ238U (from +0.1 to -0.3‰) and an increase in Th/U from shallow-marine carbonates during the Paleocene-Eocene thermal maximum at Tingri (south Tibet). Changes of δ238U and Th/U are not fully coupled. The decline in δ238U coincided with a local sea-level fall, whereas the increase in Th/U occurred mainly during a sea-level rise. The decline in δ238U likely results from changes in redox conditions of pore waters and in primary carbonate mineralogy. The increase in Th/U is ascribed to reduced authigenic U(IV) accumulation. Here our results suggest that changes in local depositional environments can cause behavior of δ238U and Th/U resembling that induced by expanded global oceanic anoxia. This finding calls for caution to consider local factors before applying δ238U and Th/U as global paleoredox proxies.
Author
Shelf entry
Permalink
- URL:
Impact factor
Access to the JCR database is permitted only to users from Slovenia. Your current IP address is not on the list of IP addresses with access permission, and authentication with the relevant AAI accout is required.
Year | Impact factor | Edition | Category | Classification | ||||
---|---|---|---|---|---|---|---|---|
JCR | SNIP | JCR | SNIP | JCR | SNIP | JCR | SNIP |
Select the library membership card:
If the library membership card is not in the list,
add a new one.
DRS, in which the journal is indexed
Database name | Field | Year |
---|
Links to authors' personal bibliographies | Links to information on researchers in the SICRIS system |
---|
Source: Personal bibliographies
and: SICRIS
The material is available in full text. If you wish to order the material anyway, click the Continue button.