Abstract
Abstract Because ice shelves respond to climatic forcing over a range of time scales, from years to millennia, an understanding of their long-term history is critically needed for predicting their future evolution. We present the first detailed reconstruction of the Larsen C Ice Shelf (LCIS), eastern Antarctic Peninsula (AP), based on data from sediment cores recovered from below and in front of the ice shelf. Sedimentologic and chronologic information reveals that the grounding line (GL) of an expanded AP ice sheet had started its retreat from the midshelf prior to 17.7 ± 0.53 calibrated (cal.) kyr B.P., with the calving line following ~6 k.y. later. The GL had reached the inner shelf as early as 9.83 ± 0.85 cal. kyr B.P. Since ca. 7.3 ka, the ice shelf has undergone two phases of retreat but without collapse, indicating that the climatic limit of LCIS stability was not breached during the Holocene. Future collapse of the LCIS would therefore confirm that the magnitudes of both ice loss along the eastern AP and underlying climatic forcing are unprecedented during the past 11.5 k.y.
Highlights
The Larsen C Ice Shelf (LCIS) is the largest remaining ice shelf on the Antarctic Peninsula (AP) and is thought to be the in line to collapse under continued climatic warming (Jansen et al, 2015)
Research revealed that the Prince Gustav Channel (PGC) (Pudsey and Evans, 2001) and Larsen A (LAIS) (Brachfeld et al, 2003) ice shelves collapsed during the mid–late Holocene, whereas the Larsen B Ice Shelf (LBIS) remained stable (Domack et al, 2005)
Unit V is overlain by the ∼10-cm-thick unit IV, which consists of laminated mud characterized by an absence of sand and gravel, a magnetic susceptibility (MS) minimum, and maxima in bromine contents (Br), total organic carbon (TOC), and kaolinite
Summary
The Larsen C Ice Shelf (LCIS) is the largest remaining ice shelf on the Antarctic Peninsula (AP) and is thought to be the in line to collapse under continued climatic warming (Jansen et al, 2015). We addressed this knowledge gap by analyzing sediment core LN2 recovered from beneath the LCIS and combined this data set with new chronological information from legacy marine core VC331, collected ∼15 km in front of the ice shelf (Fig. 1B) (Curry and Pudsey, 2007).
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