Dominant 100,000-year precipitation cyclicity in a late Miocene lake from northeast Tibet
نویسندگان
چکیده
East Asian summer monsoon (EASM) precipitation received by northern China over the past 800 thousand years (ky) is characterized by dominant 100-ky periodicity, mainly attributed to CO2 and Northern Hemisphere insolation-driven ice sheet forcing. We established an EASM record in the Late Miocene from lacustrine sediments in the Qaidam Basin, northern China, which appears to exhibit a dominant 100-ky periodicity similar to the EASM records during the Late Quaternary. Because evidence suggests that partial or ephemeral ice existed in the Northern Hemisphere during the Late Miocene, we attribute the 100-ky cycles to CO2 and Southern Hemisphere insolation-driven Antarctic ice sheet forcing. This indicates a >6-million year earlier onset of the dominant 100-ky Asian monsoon and, likely, glacial and CO2 cycles and may indicate dominant forcing of Northern Hemisphere climate by CO2 and Southern Hemisphere ice sheets in a warm world.
منابع مشابه
Late Miocene upward and outward growth of eastern Tibet and decreasing monsoon rainfall over the northwestern Indian subcontinent since ∼10 Ma
[1] Many geologic observations suggest that the eastern portion of the Tibetan Plateau has expanded eastward and grown in height over the past 15-10 Ma, and other observations suggest that climate over the northwestern Indian subcontinent (“NW India”) became more arid between 11 and 7 Ma. We suggest that they are linked: higher terrain increased orographic precipitation over eastern Tibet, whic...
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