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Iceberg calving from the Amery Ice Shelf, East Antarctica

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posted on 2023-05-16, 13:29 authored by Fricker, HA, Neal YoungNeal Young, Ian AllisonIan Allison, Richard ColemanRichard Coleman
We investigate the iceberg-calving cycle of the Amery Ice Shelf (AIS), East Antarctica, using evidence acquired between 1936 and 2000. The most recent major iceberg-calving event occurred between late 1963 and early 1964, when a large berg totalling about 10 000 km2 in area broke from the ice front. The rate of forward advance of the ice front is presently 1300-1400 m a 1. At this rate of advance, based on the present ice-front position from recent RADARSAT imagery, it would take 20-25 years to attain the 1963 (pre-calve) position, suggesting that the AIS calving cycle has a period of approximately 60-70 years. Two longitudinal (parallel-to-flow) rifts, approximately 25 km apart at the AIS front, are observed in satellite imagery acquired over the last 14+ years. These rifts have formed at suture zones in the ice shelf, where neighbouring flow-bands have separated in association with transverse spreading. The rifts were 15 km (rift A) and 26 km (rift B) in length in September 2000, and will probably become the sides of a large tabular iceberg (25 km × 25 km). A transverse (perpendicular-to-flow) fracture, visible at the upstream end of rift A in 1996, had propagated 6 km towards rift B by September 2000; when it meets rift B the iceberg will calve. A satellite image acquired in 1962 shows an embayment of this size in the AIS front, hence we deduce that this calving pattern also occured during the last calving cycle, and therefore that the calving behaviour of the AIS apparently follows a regular pattern.

History

Publication title

Annals of Glaciology

Volume

34

Pagination

241-246

ISSN

0260-3055

Department/School

Institute for Marine and Antarctic Studies

Publisher

International Glaciological Society

Place of publication

Cambridge, UK

Repository Status

  • Restricted

Socio-economic Objectives

Social impacts of climate change and variability

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