In:
Quaternary Research, Cambridge University Press (CUP), Vol. 53, No. 2 ( 2000-03), p. 154-166
Abstract:
Lake-level history for Birch Lake, Alaska, was reconstructed using seismic profiles and multiproxy sedimentary analyses including sedimentology, geochemistry, magnetic susceptibility, and palynology. Twenty-two seismic profiles (18 km total) and eight sediment cores taken from the lake margin to its depocenter at 13.5 m provide evidence for low lake stands during the late Pleistocene and Holocene. Thirty-one AMS radiocarbon dates of macrofossils and pollen provide a century-scale chronology. Prior to 12,700 14 C yr B.P., the lake, which now overflows, was either seasonally dry or desiccated for prolonged periods, indicating a severe period of aridity. Lake level rose more than 18 m between 12,700 and 12,200 14 C yr B.P. before falling to 17 m below the level of overflow. Between 11,600 and 10,600 14 C yr B.P. the water remained between 14 and 17 m below the overflow level. Onlap sedimentary sequences were formed during a transgression phase between 10,600 and 10,000 14 C yr B.P. Between 10,000 and about 8800 14 C yr B.P. the lake was between 6 and 9 m below the overflow level. Lake level again rose, approaching the overflow level, between 8800 and 8000 14 C yr B.P. Seismic and core evidence of minor erosional events suggest lowstands of 2–6 m until 4800 14 C yr B.P. There have been no prolonged periods of lake-level depression since that time. The major restructuring of the climate system during deglaciation evidently generated a complex set of fluctuations in effective moisture in interior Alaska, which likely affected eolian processes and vegetation development, as well as lake levels.
Type of Medium:
Online Resource
ISSN:
0033-5894
,
1096-0287
DOI:
10.1006/qres.1999.2112
Language:
English
Publisher:
Cambridge University Press (CUP)
Publication Date:
2000
detail.hit.zdb_id:
1471589-2
detail.hit.zdb_id:
205711-6
SSG:
13
SSG:
14
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