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Clarkia fossil beds
The Clarkia fossil beds (also known locally as the Fossil Bowl) is a Miocene lagerstätte near Clarkia, Idaho.
The fossil beds were laid down in a lake roughly 15-million-years ago, when a drainage basin was dammed by the flood basalts of the Columbia River Plateau. Narrow and deep, the lake's cold, anoxic water and rapid sedimentation created perfect fossil conditions. The basin itself has remained tectonically stable, with little deformation since then. The fossils indicate that the region's climate was much warmer and wetter than today's, and similar to that of southern Florida.〔Anonymous( 2006) (''Digging Up Ancient Treasures in Clarkia.'' ) New West, August Publications.〕〔Rember WC (2007) (''The Clarkia Flora of northern Idaho.'' ) University of Idaho, Moscow, Idaho.〕
Though a number of animal species have been found, the Clarkia fossil beds site is best known for its fossil leaves. Their preservation is exquisite; fresh leaves are unfossilized, and sometimes retain their fall colors before rapidly oxidizing in air.〔〔 It has been reported that scientists have managed to isolate small amounts of DNA from fossil leaves from this site.〔Kim, S, DE Soltis, PS Soltis, and Y Suh (2004) (''DNA sequences from Miocene fossils: an ndhF sequence of Magnolia latahensis (Magnoliaceae) and an rbcL sequence of Persea pseudocarolinensis (Lauraceae).'' ) American Journal of Botany. 91(4):615-620.〕 However, other scientists are skeptical of the validity of this reported occurrence of Miocene DNA. They have interpreted the DNA that has been recovered from these leaf fossils as contamination, probably from bacterial sources.〔Lindahl, T (1993) ''Instability and decay of the primary structure of DNA.'' Nature. 362:709–715.〕〔Sidow, A, AC Wilson, and S and Paabo (1991) ''Bacterial DNA in Clarkia fossils.'' Philosophical Transactions of the Royal Society of London Series B. 333:429–433.〕〔Balmer AJ (2013) (''Jurassic Park and the Race for Ancient DNA.'' ) Guest Blog, August 1, 2013, Scientific American.〕
==References==
抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』
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