Computer Science
Scientific paper
Nov 2011
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2011gecoa..75.6361s&link_type=abstract
Geochimica et Cosmochimica Acta, Volume 75, Issue 21, p. 6361-6373.
Computer Science
Scientific paper
The integrity of coral-based reconstructions of past climate variability depends on a comprehensive knowledge of the effects of post-depositional alteration on coral skeletal geochemistry. Here we combine millimeter-scale and micro-scale coral Sr/Ca data, scanning electron microscopy (SEM) images, and X-ray diffraction with previously published δ18O records to investigate the effects of submarine and subaerial diagenesis on paleoclimate reconstructions in modern and young sub-fossil corals from the central tropical Pacific. In a 40-year-old modern coral, we find secondary aragonite is associated with relatively high coral δ18O and Sr/Ca, equivalent to sea-surface temperature (SST) artifacts as large as -3 and -5 °C, respectively. Secondary aragonite observed in a 350-year-old fossil coral is associated with relatively high δ18O and Sr/Ca, resulting in apparent paleo-SST offsets of up to -2 and -4 °C, respectively. Secondary Ion Mass Spectrometry (SIMS) analyses of secondary aragonite yield Sr/Ca ratios ranging from 10.78 to 12.39 mmol/mol, significantly higher compared to 9.15 ± 0.37 mmol/mol measured in more pristine sections of the same fossil coral. Widespread dissolution and secondary calcite observed in a 750-year-old fossil coral is associated with relatively low δ18O and Sr/Ca. SIMS Sr/Ca measurements of the secondary calcite (1.96-9.74 mmol/mol) are significantly lower and more variable than Sr/Ca values from more pristine portions of the same fossil coral (8.22 ± 0.13 mmol/mol). Our results indicate that while diagenesis has a much larger impact on Sr/Ca-based paleoclimate reconstructions than δ18O-based reconstructions at our site, SIMS analyses of relatively pristine skeletal elements in an altered coral may provide robust estimates of Sr/Ca which can be used to derive paleo-SSTs.
Cobb Kim M.
Cohen Anne L.
Crawford Elliott W.
Dunbar Robert B.
Nurhati Intan S.
No associations
LandOfFree
Effects of diagenesis on paleoclimate reconstructions from modern and young fossil corals does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Effects of diagenesis on paleoclimate reconstructions from modern and young fossil corals, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Effects of diagenesis on paleoclimate reconstructions from modern and young fossil corals will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-738035