Post-glacial sea-level change along the Pacific coast of North America

Dan H. Shugar, Ian J. Walker, Olav B. Lian, Jordan B.R. Eamer, Christina Neudorf, Duncan McLaren, Daryl Fedje

Research output: Contribution to journalArticle

54 Scopus citations

Abstract

Sea-level history since the Last Glacial Maximum on the Pacific margin of North America is complex and heterogeneous owing to regional differences in crustal deformation (neotectonics), changes in global ocean volumes (eustasy) and the depression and rebound of the Earth's crust in response to ice sheets on land (isostasy). At the Last Glacial Maximum, the Cordilleran Ice Sheet depressed the crust over which it formed and created a raised forebulge along peripheral areas offshore. This, combined with different tectonic settings along the coast, resulted in divergent relative sea-level responses during the Holocene. For example, sea level was up to 200m higher than present in the lower Fraser Valley region of southwest British Columbia, due largely to isostatic depression. At the same time, sea level was 150m lower than present in Haida Gwaii, on the northern coast of British Columbia, due to the combined effects of the forebulge raising the land and lower eustatic sea level. A forebulge also developed in parts of southeast Alaska resulting in post-glacial sea levels at least 122m lower than present and possibly as low as 165m. On the coasts of Washington and Oregon, as well as south-central Alaska, neotectonics and eustasy seem to have played larger roles than isostatic adjustments in controlling relative sea-level changes.

Original languageEnglish (US)
Pages (from-to)170-192
Number of pages23
JournalQuaternary Science Reviews
Volume97
DOIs
StatePublished - Aug 1 2014
Externally publishedYes

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Keywords

  • Cascadia
  • Coastal geomorphology
  • Holocene glaciation
  • Isostasy
  • Neotectonics
  • Relative sea level

ASJC Scopus subject areas

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

Cite this

Shugar, D. H., Walker, I. J., Lian, O. B., Eamer, J. B. R., Neudorf, C., McLaren, D., & Fedje, D. (2014). Post-glacial sea-level change along the Pacific coast of North America. Quaternary Science Reviews, 97, 170-192. https://doi.org/10.1016/j.quascirev.2014.05.022