GSSP for Greenlandian Stage
Definition:
The base of the Greenlandian Stage (Lower/ Early Holocene Subseries/Subepoch)
of the Holocene Series/Epoch is defined in the NGRIP ice-core
record at a depth of 1492.45m at the horizon which shows the clearest
signal of climatic warming, an event that marks the end of the last
cold episode (Younger Dryas Stadial/Greenland Stadial 1) of the
Pleistocene.
Location:
The Greenlandian GSSP is located in the borehole NGRIP2 in the central Greenland ice
sheet at a latitude of 75.10°N and a longitude of 42.32°W.
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Sedimentology:
The NGRIP2 ice core consists almost entirely of glacier ice.
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Primary Markers:
The base of the Greenlandian Stage is defined on the basis of the
marked change in deuterium excess values that occurred over an
interval of ca. 3 yr.
Secondary Markers:
Over several decades, the 18O changes from glacial to
interglacial values (reflecting the temperature-dependent nature of
the fractionation of oxygen isotopes).
Dust concentrations drop an order of magnitude, reflecting a reduction
in dust flux to the ice sheet from arid or poorly vegetated regions.
Lower Na+ values in the decades after the shift in
deuterium excess
suggest reduced transfer of sea-salt particles to the ice and hence
less stormy conditions in the North Atlantic.
Annual precipitation, as reflected in annual ice-layer thickness,
increases by a factor of two during the first one or two decades
immediately after the observed change in deuterium excess. This
reflects the fact that climatic warming is accompanied by an increase
in precipitation (and hence thicker ice layers) and is a feature seen
in all polar ice cores at similar climatic transitions.
Correlation Events:
Climatic -- End of the Younger Dryas cold spell, which is reflected
in a shift in deuterium excess values
Other Locations around the World:
Global auxiliary stratotypes have been established in the Eifelmaar
Lakes in Germany, in Splan Pond, Canada, in Lake Maratoto, New
Zealand, in Lake Suigetsu, Japan and in the Cariaco Basin, Venezuela.
Notes on Derivation of Age:
Annual layer counting in ice core ("ka" is relative to AD2000); counting
uncertainy is 69 years
References:
Walker, M., Johnsen, S., Rasmussen, S.O., Steffensen, J-P., Popp, T., Gibbard,
P., Hoek, W., Lowe, J., Andrews, J., Björck, S., Cwynar, L., Hughen, K.,
Kershaw, P., Kromer, B., Litt, T., Lowe, D.J., Nakagawa, T., Newnham R., and
Schwande, J., 2008. The Global Stratotype Section and Point (GSSP) for the base
of the Holocene Series/Epoch (Quaternary System/Period) in the NGRIP ice core.
Episodes 31/2,
Walker, M., Johnsen, S., Rasmussen, S. O., Popp, T., Steffensen, J.-P., Gibbard,
P., Hoek, W., Lowe, J., Andrews, J., Björck, S., Cwynar, L. C., Hughen, K.,
Kershaw, P., Kromer, B., Litt, T., Lowe, D. J., Nakagawa, T., Newnham, R., and
Schwander, J. 2009. Formal definition and dating of the GSSP (Global Stratotype
Section and Point) for the base of the Holocene using the Greenland NGRIP ice
core, and selected auxiliary records. J. Quaternary Sci., Vol. 24 pp. 3-17.
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.
