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

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.