Variability of Southwest Indian summer monsoon precipitation during the Bølling-Ållerød

Abstract

We have generated a high-resolution (<20 yr) 2 3 0 Th-dated stalagmite oxygen isotope record from Timta Cave in the western Himalaya in India that documents Southwest Indian summer monsoon (ISM) precipitation variations during the Bolling-Allerod interstadial from 15.2 to 11.7 ka. Compared with the glacial and Younger Dryas, ISM precipitation was enhanced during the Bolling-Allerod. ISM precipitation was apparently coupled to variations in the East Asian monsoon and North Atlantic climate on millennial and multicentennial time scales during the deglaciation. Analyses of a high growth rate interval (<2.5 yr resolution) encompassing the late Bolling-early Alterod suggest that multidecadal monsoon variability was an important aspect of ISM behavior at that time. The frequency spectrum of ISM precipitation during this time interval is similar to that of the Δ 1 4 C record and other ISM precipitation records during'the latest Holocene. This raises the hypothesis that multidecadal climate dynamics during the late Boiling-early Allerod may have been similar to those that operated during the last several millennia, even though the boundary conditions of these two time intervals were very different.