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- W4280496075 abstract "The Olduvai Gorge Coring Project (OGCP) recovered sequences of Pleistocene lake sediments that correlate with those known from outcrops directly associated with hominin fossil horizons. The sedimentary succession from Core 2A (02° 58′ 43′' S, 035° 19′ 25.5′' E), which targeted the ancient lake-basinal depocenter, includes stratigraphic intervals (∼1.86 Ma) sandwiched between the Bed I basalt and Tuff IF dated horizons, where remains of two hominin holotypes have been recovered. The lower part of this sequence (72.3–86.9 mbs) consists of lacustrine claystones interbedded with sandy claystones characterized by high Corg (av. 2.5%) and includes several laminated intervals. It displays shifts in terrestrial vegetation recorded by values for δ13CTOC and δ2HnC31 that reflect changes in the proportions of C3 vs C4 plants and precipitation, respectively. These temporal profiles represent higher-resolution signatures of the precession-scale wet/dry cycles previously recognized in the outcropping sedimentary succession of Olduvai Gorge. Several samples from this interval contain alkenones comprising C37 and C39 alkadien-2-ones and alkatrien-2-ones, and C38 and C40 alkadien-3-ones and alkatrien-3-ones. They are distinguished from the vast majority of alkenone distributions reported in lake sediments from polar and temperate latitudes (e.g., Greenland, N. and S. America, Europe, Russia, China, S. Africa, Antarctica) by the absence of tetraunsaturated alkenones (e.g., C37:4). The alkenone distributions vary stratigraphically with higher concentrations in the drier intervals of the precession-scale cycles that exhibit characteristics resembling those of Group II haptophytes found in contemporary saline/alkaline environments rather than those of Group I haptophytes from freshwater ecosystems. Paleolake Olduvai represents the first reported occurrence of alkenones in a low-latitude Pleistocene lake, where the absence of alkatetraenones may reflect contributions from strains of Group II haptophytes that are favored by warmer temperatures or saline conditions. Temporal variations in unsaturation indices (U37K', U38K') and the proportions of alken-2-ones and alken-3-ones likely reflect influences on alkenone production by haptophytes that are associated with changes in the lake environment primarily driven by hydrologic cycles (e.g., salinity and alkalinity) rather than lake temperatures." @default.
- W4280496075 created "2022-05-22" @default.
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- W4280496075 date "2022-08-01" @default.
- W4280496075 modified "2023-09-27" @default.
- W4280496075 title "Alkenones in Pleistocene Upper Bed I (1.803–1.900 Ma) sediments from Paleolake Olduvai, Tanzania" @default.
- W4280496075 cites W1147853437 @default.
- W4280496075 cites W1172779727 @default.
- W4280496075 cites W1814948295 @default.
- W4280496075 cites W1964028410 @default.
- W4280496075 cites W1968417232 @default.
- W4280496075 cites W1968465551 @default.
- W4280496075 cites W1968630644 @default.
- W4280496075 cites W1970433533 @default.
- W4280496075 cites W1971292778 @default.
- W4280496075 cites W1972601372 @default.
- W4280496075 cites W1974310189 @default.
- W4280496075 cites W1976060931 @default.
- W4280496075 cites W1976255883 @default.
- W4280496075 cites W1976632205 @default.
- W4280496075 cites W1977077054 @default.
- W4280496075 cites W1979278940 @default.
- W4280496075 cites W1982073239 @default.
- W4280496075 cites W1982375267 @default.
- W4280496075 cites W1982561159 @default.
- W4280496075 cites W1984434762 @default.
- W4280496075 cites W1989056503 @default.
- W4280496075 cites W1989895620 @default.
- W4280496075 cites W1990610953 @default.
- W4280496075 cites W1991795942 @default.
- W4280496075 cites W1993368675 @default.
- W4280496075 cites W1994945849 @default.
- W4280496075 cites W1996678998 @default.
- W4280496075 cites W2000559916 @default.
- W4280496075 cites W2002431620 @default.
- W4280496075 cites W2002631603 @default.
- W4280496075 cites W2003175006 @default.
- W4280496075 cites W2007613935 @default.
- W4280496075 cites W2008205524 @default.
- W4280496075 cites W2009894319 @default.
- W4280496075 cites W2013125004 @default.
- W4280496075 cites W2014646959 @default.
- W4280496075 cites W2019205466 @default.
- W4280496075 cites W2023742734 @default.
- W4280496075 cites W2024162194 @default.
- W4280496075 cites W2024752826 @default.
- W4280496075 cites W2029771879 @default.
- W4280496075 cites W2030204142 @default.
- W4280496075 cites W2030480980 @default.
- W4280496075 cites W2031154358 @default.
- W4280496075 cites W2032482799 @default.
- W4280496075 cites W2033136384 @default.
- W4280496075 cites W2038008886 @default.
- W4280496075 cites W2043810485 @default.
- W4280496075 cites W2045502051 @default.
- W4280496075 cites W2045635498 @default.
- W4280496075 cites W2045725333 @default.
- W4280496075 cites W2046527386 @default.
- W4280496075 cites W2048736764 @default.
- W4280496075 cites W2050416604 @default.
- W4280496075 cites W2053190053 @default.
- W4280496075 cites W2053251742 @default.
- W4280496075 cites W2055221486 @default.
- W4280496075 cites W2055406492 @default.
- W4280496075 cites W2055532735 @default.
- W4280496075 cites W2057007096 @default.
- W4280496075 cites W2058239031 @default.
- W4280496075 cites W2064384047 @default.
- W4280496075 cites W2064995128 @default.
- W4280496075 cites W2066223531 @default.
- W4280496075 cites W2067308263 @default.
- W4280496075 cites W2069207559 @default.
- W4280496075 cites W2069623298 @default.
- W4280496075 cites W2070457098 @default.
- W4280496075 cites W2072981068 @default.
- W4280496075 cites W2073088022 @default.
- W4280496075 cites W2075299813 @default.
- W4280496075 cites W2080322006 @default.
- W4280496075 cites W2080449769 @default.
- W4280496075 cites W2082982287 @default.
- W4280496075 cites W2083392509 @default.
- W4280496075 cites W2086155711 @default.
- W4280496075 cites W2087629674 @default.
- W4280496075 cites W2087683608 @default.
- W4280496075 cites W2088339533 @default.
- W4280496075 cites W2089528235 @default.
- W4280496075 cites W2089596179 @default.
- W4280496075 cites W2090147630 @default.
- W4280496075 cites W2091232642 @default.
- W4280496075 cites W2091284813 @default.