T205 Growing a Skeleton: Methodological and Theoretical Approaches to Unraveling the Stories Preserved in Skeletal Materials II

Thursday, 29 October 2020
1:30 PM - 5:30 PM
Meeting Rooms

RECONSTRUCTING SEASONAL-SCALE PRECIPITATION PATTERNS FROM HIGH RESOLUTION OXYGEN ISOTOPE SCLEROCHRONOLOGY OF COASTAL TURRITELLID GASTROPODS

Paper number: T205-14
Program: Technical Sessions
Time: 4:20 PM – 4:30 PM

Authors

Abstract

Turritellid gastropods are aragonitic marine mollusks which are particularly abundant and widespread in the fossil record. With fast growth rates and a shallow coastal living environment, they have the potential to be excellent recorders of ancient subannual climate variation – both seasonal temperature changes and fluctuations in δ18Osw. Previous sclerochronological studies of turritellids have investigated seasonal temperature ranges by converting δ18O to temperature, assuming an invariant δ18Osw. However, this approach is complicated by naturally variant δ18Osw in the marginal marine environments where turritellids live, driven by seasonally variable freshwater delivery related to local rainfall patterns. We produce 22 new high-resolution oxygen isotope profiles of modern turritellid shells, and compare these and other published records to instrumental temperature and precipitation data in order to assess the potential of turritellids to record past sea surface temperatures and seasonal precipitation patterns. We find that the annual range in shell δ18O is related to seasonal precipitation variance (the difference in rainfall between wettest and driest month, SPV), once seasonal changes in sea surface temperature are accounted for. We demonstrate the effects of alignment vs. misalignment of precipitation and temperature maxima on δ18O profiles using modeled synthetic data. This empirical relationship between δ18Orange, SST and SPV can be used to reconstruct paleoenvironmental conditions, particularly in the tropics where seasonal precipitation has a strong effect on δ18O.

Geological Society of America Abstracts with Programs. Vol. 52, No. 6

doi: 10.1130/abs/2020AM-352637

© Copyright 2020 The Geological Society of America (GSA), all rights reserved. Permission is hereby granted to the author(s) of this abstract to reproduce and distribute it freely, for noncommercial purposes. Permission is hereby granted to any individual scientist to download a single copy of this electronic file and reproduce up to 20 paper copies for noncommercial purposes advancing science and education, including classroom use, providing all reproductions include the complete content shown here, including the author information. All other forms of reproduction and/or transmittal are prohibited without written permission from GSA Copyright Permissions.