Abstract
AbstractSr‐isotope measurements of unaltered oyster shell calcite using laser‐ablation multi‐collector ICPMS techniques represent a powerful tool capable of establishing a chronostratigraphic framework for fossil near‐shore deposits. This approach is tested on two shoal‐water successions from the Portuguese Algarve and Lusitanian basins covering Late Barremian to Albian strata. 87Sr/86Sr values derived from low‐Mg calcite of oyster shells fluctuate between 0.70717 ± 0.00001 and 0.70746 ± 0.00002; absolute values as well as stratigraphic trends match well with the global open‐marine seawater signal. The new Sr‐isotope results in combination with existing bio‐ and chemostratigraphic records allow for identification of an Early Aptian biocalcification crisis at both studied localities and show that this event has severely affected coastal environments along the evolving Atlantic. Siliciclastic intervals in the Algarve section are interpreted as near‐shore equivalents of enhanced detrital shedding into shelf and deep‐sea environments as a consequence of increased chemical weathering rates during humid climate episodes.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.