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SUMMARY Fossil corals are commonly used to reconstruct Last Interglacial (∼125 ka, LIG) sea level. Sea level reconstructions assume the water depth at which the coral lived, called the ‘relative water depth’. However, relative water depth varies in time and space due to coral reef growth in response to relative sea level (RSL) changes. RSL changes can also erode coral reefs, exposing older reef surfaces with different relative water depths. We use a simplified numerical model of coral evolution to investigate how sea level history systematically influences the preservation of corals in the Bahamas and western Australia, regions which house >100 LIG coral fossils. We construct global ice histories spanning the uncertainty of LIG global mean sea level (GMSL) and predict RSL with a glacial isostatic adjustment model. We then simulate coral evolution since 132 ka. We show that preserved elevations and relative water depths of modelled LIG corals are sensitive to the magnitude, timing and number of GMSL highstand(s). In our simulations, the influence of coral growth and erosion (i.e. the ‘growth effect’) can have an impact on RSL reconstructions that is comparable to glacial isostatic adjustment. Thus, without explicitly accounting for the growth effect, additional uncertainty is introduced into sea level reconstructions. Our results suggest the growth effect is most pronounced in western Australia due to Holocene erosion, but also plays a role in the Bahamas, where LIG RSL rose rapidly due to the collapsing peripheral bulge associated with Laurentide Ice Sheet retreat. Despite the coral model's simplicity, our study highlights the utility of process-based RSL reconstructions.
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A global compilation of U-series-dated fossil coral sea-level indicators for the Last Interglacial period (Marine Isotope Stage 5e)
Abstract. This dataset is a comprehensive, global compilation ofpublished uranium–thorium (U-series) dated fossil coral records from∼ 150 000–110 000 years ago, as well as associatedelevation measurements and sample metadata. In total, 1312 U-seriesmeasurements from 994 unique coral colonies are included in the currentversion of the dataset, all of which have been normalized and recalculatedusing the same decay constant values. Of these measurements, 444 analysesfrom 330 colonies are relative sea-level indicators, whereas 15 analysesfrom 13 colonies are marine limiting. Two example geochemical screeningcriteria have been included to assist users with identifying altered fossilcorals that display geochemical open-system behavior, and the originallypublished interpretations on age quality have been preserved within thesample metadata. Additionally, a clear distinction has been made betweencoral colonies that are in primary growth position, which may be used forrelative sea-level reconstructions, and colonies that have beentransported/reworked, which cannot be used for these purposes. Futureresearch efforts involving fossil coral sea-level reconstructions shouldemphasize an “integrated” and holistic approach that combines carefulassessment of U-series age quality with high-precision surveying techniquesand detailed facies/stratigraphic observations. This database is availableat https://doi.org/10.5281/zenodo.4309796 (Chutcharavan andDutton, 2020).
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- Award ID(s):
- 2041325
- PAR ID:
- 10318713
- Date Published:
- Journal Name:
- Earth System Science Data
- Volume:
- 13
- Issue:
- 7
- ISSN:
- 1866-3516
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.5194/essd-13-3155-2021
