Prosiectau fesul blwyddyn
Crynodeb
Rates of ice-stream retreat over decades can be determined from repeated satellite surveys and over millennia by paleoenvironmental reconstructions. Centennial time scales are an important temporal gap in geological observations of value in process understanding and evaluation of numerical models. We address this temporal gap by developing a 3 ka and 123 km retreat time series for the Irish Sea ice stream (ISIS), a major outlet draining the last British-Irish ice sheet. The Llŷn Peninsula (northwest Wales, UK) contains numerous ice-marginal indicators from which we reconstructed a robust chronological framework of margin oscillations. The landscape documents the retreat of a former marine-terminating ice stream through a topographic constriction, across a reverse bed slope, and across variations in calving margin width. New dating constraints for this sequence were integrated in a Bayesian sequence model to develop a high-resolution ice-retreat chronology. Our results show that retreat of the ISIS during the period 24-20 ka displayed centennial-scale oscillatory behavior of the margin despite relatively stable climatic, oceanic, and relative sea-level forcing mechanisms. Faster retreat rates coincided with greater axial trough depths as the ice passed over a reverse bed slope and the calving margin widened (from 65 to 139 km). The geological observations presented here over a 123-km-long ice-retreat sequence are consistent with theory that marine-based ice can be inherently unstable when passing over a reverse bed slope, but also that wider calving margins lead to much faster ice retreat.
Iaith wreiddiol | Saesneg |
---|---|
Tudalennau (o-i) | 787-790 |
Nifer y tudalennau | 4 |
Cyfnodolyn | Geology |
Cyfrol | 45 |
Rhif cyhoeddi | 9 |
Dynodwyr Gwrthrych Digidol (DOIs) | |
Statws | Cyhoeddwyd - 01 Medi 2017 |
Ôl bys
Gweld gwybodaeth am bynciau ymchwil 'Internal dynamics condition centennial-scale oscillations in marine based ice stream retreat'. Gyda’i gilydd, maen nhw’n ffurfio ôl bys unigryw.Proffiliau
Prosiectau
- 1 Wedi Gorffen
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Britice - Chrono: Constraining Rates and Style of Marine Influenced Ice Sheet Decay
Duller, G. (Prif Ymchwilydd)
Natural Environment Research Council
19 Tach 2012 → 18 Tach 2017
Prosiect: Ymchwil a ariannwyd yn allanol