NOAA/WDS Paleoclimatology - Shakun et al. 2007 Socotra Island, Yemen Stalagmite Stable Isotope Data

STUDY NOTES: This dataset contains stable oxygen and carbon isotopes from stalagmite M1-5 from Moomi Cave, Socotra Island, Yemen (12º30'N, 54ºE) covering the interval ~27-11 ka in decadal resolution. 717 samples in total were drilled along the speleothem's growth axis using a 0.5 mm carbide dental burr and analyzed on a Finnegan Delta XL ratio mass spectrometer at the University of Massachusetts. 28 230-Th dates constrain the chronology and were measured at the University of Bern.
ABSTRACT SUPPLIED BY ORIGINATOR: Stalagmite M1-5 from Socotra Island, Yemen in the northwest Indian Ocean provides a robust, high-resolution paleoclimate record from ~27.4 - 11.1 ka based on 717 stable isotope and 28 230Th measurements. Variations in M1-5 oxygen isotope ratios (d18O) are interpreted to be primarily driven by an amount effect related to changes in the mean position and/or intensity of convection of the intertropical convergence zone, the island's only source of precipitation. The M1-5 d18O time series is strongly correlated to the Greenland ice cores, similar to an older Socotra speleothem deposited from 53-40ka [S.J. Burns, D. Fleitmann, A. Matter, J. Kramers, A. Al-Subbary, Indian Ocean climate and an absolute chronology over Dansgaard/Oeschger events 9 to 13, Science 301 (2003) 1365 - 1367], indicating that a North Atlantic - Indian Ocean cold-dry/warm-wet teleconnection persisted through the end of the last glacial period. Peak aridification occurred at ~23 ka and a gradual increase in moisture thereafter was interrupted by an abrupt drying event at ~16.4 ka, perhaps related to Heinrich event 1. Indian Ocean rainfall increased dramatically during the Bølling period and then decreased continuously and gradually through the Allerød and Younger Dryas. The Holocene began abruptly with increased precipitation at 11.4 ka and was followed by a major but short-lived drying during the Preboreal Oscillation at ~11.2 ka. M1-5 is highly correlated to the Dongge Cave record from 15.5 - 11 ka, suggesting much of the Indian Ocean monsoon region responded similarly to the major climate changes of the last deglaciation. The transitions into the Younger Dryas and to a lesser extent the Bølling are remarkably gradual in M1-5, as they are in all other Asian speleothem records, occurring over several centuries. These gradual transitions are in striking contrast to high-resolution records from around the North Atlantic basin where the transitions are extremely abrupt and generally occur in under a century. This spatially variable pattern of climate change is consistent with an Atlantic origin for these deglacial climate events.