Fossil Java Sea corals record Laurentide ice sheet disappearance

The Laurentide ice sheet was the largest late Pleistocene ice mass and the largest contributor to Holocene pre-industrial sea-level rise. While glaciological dates suggest final ice sheet melting between 8 and 6 ka, inversion of sea-level data indicates deglaciation at ca. 7 ka. Here, we present new...

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Bibliographic Details
Published in:Geology (Boulder) 2023-07, Vol.51 (7), p.631-636
Main Authors: Mann, Thomas, Schöne, Tilo, Kench, Paul, Lambeck, Kurt, Ashe, Erica, Kneer, Dominik, Beetham, Eddie, Illigner, Julia, Rovere, Alessio, Marfai, Muh Aris, Westphal, Hildegard
Format: Article
Language:English
Subjects:
Anthozoa
atolls
C-14
carbon
Cenozoic
chronostratigraphy
Climate change
Cnidaria
Corals
Deglaciation
Fossils
Geology
glacial geology
Glaciation
global change
Global warming
Holocene
Ice
Ice sheet melting
Ice sheets
Indonesian Seas
isotopes
Java Sea
Laurentide ice sheet
Meltwater
Microatolls
Modelling
Pacific Ocean
Pleistocene
Prediction models
Quaternary
Quaternary geology
radioactive isotopes
reefs
Sea level
Sea level changes
Sea level rise
Sea level trends
South Pacific
Southwest Pacific
Trends
upper Pleistocene
West Pacific
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Summary:The Laurentide ice sheet was the largest late Pleistocene ice mass and the largest contributor to Holocene pre-industrial sea-level rise. While glaciological dates suggest final ice sheet melting between 8 and 6 ka, inversion of sea-level data indicates deglaciation at ca. 7 ka. Here, we present new chronostratigraphic constraints on Laurentide ice sheet disappearance based on Holocene relative sea-level observations from the tectonically stable north coast of Java, Indonesia. Age-elevation data from the flat upper surfaces of 13 fossil intertidal corals (i.e., microatolls) indicate that the Java Sea experienced a relative sea level of 1.3±0.7 m above present between 6.9 and 5.3 ka. To determine uncaptured relative sea-level trends within the observational uncertainties of this apparently constant highstand, we analyzed the internal structure of three sliced microatolls from the same site to produce a high-resolution data set. These data were used to statistically model relative sea-level rates and trends. Employing the data with the model provided evidence for a short-lived rise of relative sea level from 1.0±0.3 m above present at 6.7±0.1 ka to 1.9±0.3 m above present at 6.4±0.1 ka. The end of this rise likely represents the last input of meltwater from the vast Laurentide ice sheet, which, consequently, collapsed at least 400 yr later than assumed by some widely used models of glacial isostatic adjustment. Incorporating these new results into such predictive models will help to better understand the geographical variability of future sea-level rise as a result of global warming.
ISSN:0091-7613
1943-2682
DOI:10.1130/G51038.1