CR 26:193-197 (2004)  -  doi:10.3354/cr026193

ABSTRACT: The current study examines the potential cyclical nature of the elemental concentration record of silicon in sediments from Lake Baikal site BDP 96-2 in an attempt to clarify trends in periodicity observed for periods from 700 kyr BP to the present, 760 kyr BP to 1.43 Ma, and 1.47 to 2.4 Ma. The results indicate the presence of the 100 kyr cycle during the past 700000 yr, as identified in other research. They also indicate the presence of a strong 74 kyr cycle from 760 kyr BP to 1.43 Ma, with a weaker 44 kyr cycle. For the period from 1.47 to 2.4 Ma, we observed evidence of strong 465 and 155 kyr cycles, in addition to a moderate 93 kyr cycle and various lesser cycles. This new evidence represents one of the first findings of longer cycles, as predicted by classic insolation theory, and sheds some initial light on Imbrie¹s 400 kyr question.

KEY WORDS: Silicon concentration · Climate change · Paleoenvironment · Milankovitch · Lake Baikal · Sediments