Tropical Climate Instability: The Last Glacial Cycle from a Qinghai-Tibetan Ice Core

Abstract

An ice core record from the Guliya ice cap on the Qinghai-Tibetan Plateau provides evidence of regional climatic conditions over the last glacial cycle. 36 Cl data suggest that the deepest 20 meters of the core may be more than 500,000 years old. The δ 18 O change across Termination I is ∼5.4 per mil, similar to that in the Huascarán (Peru) and polar ice cores. Three Guliya interstadials (Stages 3, 5a, and 5c) are marked by increases in δ 18 O values similar to that of the Holocene and Eemian (∼124,000 years ago). The similarity of this pattern to that of CH 4 records from polar ice cores indicates that global CH 4 levels and the tropical hydrological cycle are linked. The Late Glacial Stage record contains numerous 200-year oscillations in δ 18 O values and in dust, NH 4 + , and NO 3 − levels.