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The loess of north-east Essex
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Thin silty deposits are widespread in N. E. Essex. They are
thickest on the coast at-the Naze where they reach nearly 1.5 m. These
deposits overlie fluvial sands and gravels though in a number of
localities there is a layer of aeolian sand (cover-sand) between the
silt and the gravel.
Up to 70% of the particle size distribution is within the silt
fraction (2-63 um) which is consistent with aeolian transport and so these
deposits are probably of loessial origin. Although the majority are classified
as sandy loess, the loessial , sediments of N. E. Essex are a textural
continuum ranging from loess to sediments approaching aeolian sand in
composition. This reflects the degree of inter-mixing of overlying
loessial silt with underlying cover-sand.
The loess is texturally similar to that in Kent but the sandy
loess, typical of inland parts, resembles deposits in Norfolk. The heavy
mineral content of loessial sediments is uniform throughout N. E. Essex
and the mineralogical similarity of the loess to underlying aeolian sand
indicates the same sources supplied the silt and sand fractions of both
sediments. The coarse silt fraction of N. E. Essex loess is like that of
loesses elsewhere in Eastern England and those of the Netherlands and Belgium
which suggests a common origin. The North Sea Basin is the likely source
and a possible deflation area north-east of the Dogger Bank is suggested.
Differences in the heavy mineral content of the sand fractions of loesses
from N. E. Essex and Norfolk probably reflects their derivation from more
local sources.
N. E. Essex loess is Devensian and accumulation probably commenced
at about the maximum extent of Devensian ice (about 18,000 Yr. B. P. ) and
continued until about 14,000 Yr. B. P. A correlation with Cover-Loams I and
II of Belgium which are -Pleniglacial B of the Weichselian, (Devensian) is
suggested.
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