Chronology and Paleoclimate of Storm-Induced Erosion and Episodic Dune Growth Across Cape Espenberg Spit, Alaska, U.S.A.

Owen K. Mason, David M. Hopkins, Lawrence Plug

Abstract


The Cape Espenberg beach ridge plain is capped by a succession of primary and secondary dune and/or blowout ridges whose 5000 yr chronostratigraphy is based on landform evolution, peat formation, pedogenesis, tephro-chronology, and geological (n = 23) and archaeological (n = 32) radiocarbon ages. Landform evolution reflects several sets of conditions: beach ridges form under fair weather wave climates and/or following subsiding storm levels, dunes build in fall and winter in conjunct ion with onshore N or NW winds, while net offshore sediment transport and erosion predominates during fall storms. Inter-ridge swales foster peat and paIsa growth atop driftwood in conjunction with thin snow cover. Dunes built during stormy intervals correlative with montane Alaska glacial expansions 3300 - 1700 14C yrs BP and from 1200-200 14C yrs BP.


Keywords


Beach ridges; geoarchaeology coastal changes; paleo-climates

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