Abstract Details

ID: 831
Title: Early Holocene ice-sheet/sea-level interactions: An underutilized analog for the future?

Early Holocene sea-level change constitutes an imperfect, yet potentially valuable analog for future sea-level rise, given the rapidly disintegrating land-based ice under climate conditions of high-latitude Northern Hemisphere warming. The associated rates of eustatic sea-level rise (cm/yr order of magnitude) fall within the range of predictions for the latter part of the next century. However, the early Holocene eustatic sea-level history is otherwise rather poorly understood. Recent impetus has been provided by new records of both relative sea-level (RSL) change and ice-sheet retreat that are sometimes difficult to reconcile in terms of timing and magnitude of change.

This presentation summarizes the state-of-the-art on early Holocene sea-level change and identifies areas of near-term research needs. Recent studies have identified a number of decimeter to meter-scale sea-level jumps, several of which have been linked to catastrophic drainage of proglacial Lake Agassiz and the 8.2 ka cooling event. On the other hand, the enigmatic 7.6 ka event has received renewed interest both by means of new RSL data and reconstructions of Laurentide Ice Sheet retreat. However, the proposed ~5 m abrupt rise in eustatic sea level in some localities cannot be detected in numerous detailed RSL records from elsewhere, thus presenting a conundrum.

Converting local observations of RSL rise into eustatic signals (including volumes and sources of meltwater discharge) will require a concerted effort that involves the integration of increasingly sophisticated field studies from strategically chosen localities around the globe in tandem with geophysical modeling. While glacial isostatic adjustment is a dominant player in many RSL records that must be fully accounted for to extract eustatic signals, there is ample room for using fingerprint theory to identify the magnitude and source regions of meltwater delivery to the ocean system.

Session: 48 Sea-level jumps: evidence from Quaternary proxy records
Authors: Torbjörn Törnqvist
Presenter:Torbjörn Törnqvist
Type: oral