Early deglacial (∼19–17 ka) strengthening of the northeast monsoon

Earlier studies that mostly relied on bulk 14 C dating indicated a weaker Southwest monsoon (SWM) and a stronger than present Northeast monsoon (NEM) during the Last Glacial Maximum (LGM, ∼18000 14 C years or ∼21000 calendar years ago). We have analyzed a sediment core from the equatorial Indian Ocean, where planktonic foraminifera were dated by Accelerator Mass Spectrometry (AMS 14 C). δ 18 O analysis of three species of foraminifera viz . Globigerinoides ruber, Globigerinoides sacculifer, and Globorotalia menardii reveals that the NEM strengthened during the early deglacial period (∼15000 14 C years ago or ∼18000 calendar years ago) relative to the present and not during the LGM as surmised earlier.