Revised chronology of northwest Laurentide ice-sheet deglaciation from 10Be exposure ages on boulder erratics

Alberto V. Reyes, Anders E. Carlson, Glenn A. Milne, Lev Tarasov, Jesse R. Reimink, Marc W. Caffee

Research output: Contribution to journalArticlepeer-review

8 Scopus citations

Abstract

We present new 10Be surface exposure ages from boulders on bedrock to directly date northwest Laurentide ice-sheet deglaciation through a wide swath of the western Canadian Shield that had no previous reliable temporal constraints on ice-margin retreat. Uplift-corrected boulder 10Be surface exposure ages are 13.9 ± 0.2 ka (n = 6) at a site on the western edge of the Slave Craton and 12.4 ± 0.2 ka (n = 5, 1 outlier) at a second site ∼110 km up-ice to the east. These direct 10Be ages for ice-margin retreat are ∼2.4 kyr and ∼1.6 kyr older, respectively, than the canonical deglacial chronology for the northwest Laurentide ice sheet that is based on minimum-limiting 14C dates. We infer an ice-margin retreat rate of 60–100 m yr−1 between the two sites over an interval spanning the transition from the Allerød warm period into the Younger Dryas cold period. This is significantly slower than the rapid >800 m yr−1 retreat rate for the northwest Laurentide ice sheet inferred from earlier deglacial chronologies, which has been hypothesized as a potential source of meltwater forcing for the Younger Dryas cold period. These first direct ages on spatio-temporal patterns of deglaciation in this data-poor region suggest that additional refinement of the deglacial chronology is needed to test hypotheses on the relation between ice-sheet retreat, associated meltwater discharge, abrupt climate change, and rapid sea-level rise.

Original languageEnglish (US)
Article number107369
JournalQuaternary Science Reviews
Volume277
DOIs
StatePublished - Feb 1 2022

All Science Journal Classification (ASJC) codes

  • Global and Planetary Change
  • Ecology, Evolution, Behavior and Systematics
  • Archaeology
  • Archaeology
  • Geology

Fingerprint

Dive into the research topics of 'Revised chronology of northwest Laurentide ice-sheet deglaciation from 10Be exposure ages on boulder erratics'. Together they form a unique fingerprint.

Cite this