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GSSP for Meghalayan


Definition:

The base of the Meghalayan Stage (Upper/Late Holocene Subseries/Subepoch) of the Holocene Series/Epoch is defined in the Mawmluh Cave speleothem in NE India and dated at 4250yr bk2 (before AD2000).


Location:

The Meghalayan GSSP is located in the northeastern Indian State of Meghalaya. The entrance of Mawmluh Cave is at the southern edge of the Meghalayan Plateau at a latitude of 25°15'44"N and a longitude of 91°42'54"W. The nearest town is Sohra (Cherrapunji).
GSSP for Meghalayan


Sedimentology:

Mawmluh Cave is overlain by 30 - 100m of limestone and sandstone and formed along the contact between the Lower Eocen Lakadong dolomite and the Therria Sandstone.


Primary Markers:

The GSSP is defined in a speleothem (KM-A) with a modelled age of 4250yr bk2 (before AD2000), where the stable isotope profile shows a shift to heavier isotopic values, reflecting an abrupt reduction in precipitation due to weakening of the monsoon across the Indian sub-continent and southeast Asia.

Correlation Events:

Stable isotope profile shows a shift to heavier isotopic values,

Other Locations around the World:

This so-called 4.2 ka event is recognized worldwide. Most mid- and low-latitude records indicate the abrupt onset of aridification. In northern and high latitudes glacier advancements are pronounced, while in Antarctica sea ice cover and lower sea surface temperatures start at 4.2ka.

References:

Walker, M., Head, M.J., Berkelhammer, M., Björck, S., Cheng, H., Cwynar, L., Fisher, D., Gkinis, V., Long, A., Lowe, j., Newnham, R., Rasmussen, S.O., Weiss, H., 2018. Formal ratification of the subdivision of the Holocene Series/ Epoch (Quaternary System/Period): two new Global Boundary Stratotype Sections and Points (GSSPs) and three new stages/ subseries. Episodes 41/4, 1-11.



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