Publication Date:
2015-11-26
Description:
Shells of the bivalve Arctica islandica serve as high-resolution archive of past
environmental conditions. Stable oxygen isotopes (δ18O) values from wellpreserved
A. islandica shells are frequently used as a proxy for water
temperature (and salinity). Hence, this species may improve distinctly our
understanding of seasonal temperature dynamics in the past.
We present the first stable isotope (δ18O & δ13C) analysis on a fossil
semi-recrystallized A. islandica shell from the Tjörnes Beds of Iceland
(Pliocene). Confocal Raman microscopy is used to identify areas of pristine
aragonite and recrystallized calcite shell, which were then sampled by highresolution
micro-milling. We compare paleo-water temperatures inferred from
stable oxygen isotope ratios of both recrystallized and non-recrystallized
portions of the shell to highlight and discuss the impacts of taphonomic
alterations on a micro-scale and its implications for paleo-environmental
reconstructions. Our findings emphasize the need for careful interpretation of
carbonate-based water temperature reconstructions, because small-scale
diagenesis can significantly modify the original stable oxygen isotope
signature and substantially distort the paleoclimatic or paleoenvironmental
signals inferred thereof.
Repository Name:
EPIC Alfred Wegener Institut
Type:
Conference
,
notRev
Format:
application/pdf
