US Geological Survey


Date of this Version



Mechanisms of Global Climate Change at Millennial Time Scales, Geophysical Monograph 112 (1999)


High-resolution (decadal) records of climate change from the Owens, Mono, and Pyramid Lake basins of California and Nevada indicate that millennial scale oscillations in climate of the Great Basin occurred between 52.6 and 9.2 14Ck a. Climate records from the Owen sand Pyramid Lake basins indicate that most, but not all, glacier advance (stades) between 52.6 and ~15.0 14C ka occurred during relatively dry times. During the last alpine glacial period (-60.0 to -14.0 4C ka), stadial/interstadial oscillations were recorded in Owens and Pyramid Lake sediments by the negative response of phytoplankton productivity to the influx of glacially derived silicates. During glacier advances, rock flour diluted the TOC fraction of lake sediments and introduction of glacially derived suspended sediment also increased the turbidity of lake water, decreasing light penetration and photosynthetic production of organic carbon. It is not possible to correlate objectively peaks in the Owens and Pyramid Lake TOC records (interstades) with Dansgaard- Oeschgeinr terstadeins the GISP2i ce-core δ18O record given uncertainties in age control and difference in the shapes of the OL90, PLC92 and GISP2 records. In the North Atlantic region, some climate records have clearly defined variability/cyclicity with periodicities of 102 to 103 yr; these records are correlatable over several thousand km. In the Great Basin, climate proxies also have clearly defined variability with similar time constants, but the distance over which this variability can be correlated remains unknown. Globally, there may be minimal spatial scales (domains) within which climate varies coherently on centennial and millennial scales, but it is likely that the sizes of these domains vary with geographic setting and time. A more comprehensive understanding of the mechanisms of climate forcing and the physical linkages between climate forcing and system response is needed in order to predict the spatial scale(s) over which climate varies coherently