A dry episode during the Younger Dryas and centennial-scale weak monsoon events during the early Holocene: A high-resolution stalagmite record from southeast of the Loess Plateau, China

摘要

A high-resolution stalagmite oxygen isotope record from Dongshiya Cave, located southeast of the Chinese Loess Plateau, reveals detailed climatic oscillations between 12.7 and 9.0 ka BP, on centennial and decadal timescales, with a temporal resolution of 1 to 20 years. The early Younger Dryas is characterized by a gradual increase in delta O-18 values, which is followed by a depositional hiatus for the remainder of the Younger Dryas, between 12.1 and 11.5 ka BP, implying a weak East Asian Monsoon or a dry climate during the Younger Dryas. Eight weak monsoon events between 11.5 and 9.0 ka BP punctuate the early Holocene East Asian Monsoon, and are likely tied to cold events in Greenland, including the Pre-boreal Oscillation and the 9.2 ky Event. The spectral analysis of the Dongshiya delta O-18 time series yields peaks at frequencies that have been linked to solar frequencies, indicating that solar changes may be, at least partially, responsible for changes in the intensity of the East Asian Monsoon during the early Holocene.