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Figure 6.2 Terminology
used in the Holocene
climatic stratigraphy
developed and modified
from the 1950s to the 1970s.
Atlantic and Boreal terms
originally developed from
a series of primarily peat
records in Europe with
several major (large jagged
lines) and minor (small
jagged lines) discontinuities.
Radiocarbon dating
modified the original time
scale to show the range of
climatic boundaries possible
for the individual
boundaries. Neoglaciation
identifies the period of
renewed alpine glacier
activity following the retreat
of glacial ice. (Modified from
Bradley 1999 )
The Greenland Ice Sheet is a very large topographic barrier to the prevail-
ing westerlies within the northern mid-latitudes. In addition, the position of
the Icelandic Low, generally close to the southern border of the island, means
that many air masses in the NHmigrate toward Greenland. Some of these will
ride over the top of the ice sheet while others will essentially collide with it
and move around its perimeter. Regardless of the eventual path taken, these
air masses bring gases, aerosols and insoluble particles to various portions of
the ice sheet. These species, scavenged by precipitation (i.e. primarily snow)
together with some dry fallout via settling by gravity, will be deposited on the
snow surface. Their concentrations are preserved as the snow is converted to
glacial ice with burial. Air found in the voids between individual snow grains
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