Geology Reference
In-Depth Information
3
The Becher Point Cuspate Foreland
and Its Wetlands—Microscale Features
table, wetlands have been inserted onto the prograded plain,
commencing some 4,500 years ago and continuing to the
present. As such, the wetlands are of different ages, and
record wetland sedimentary
lling of different durations, set
in the mid- to late-Holocene climate change, and the shorter
term 250-year climate cycles, and interacting with an
evolving hydrology and hydrochemistry, all features re
Whilst the area of Becher Point has been recognised as of
International signi
cance and afforded protection as a
Ramsar site (mostly for its macroscopic features such as
beach rides, wetland basins, and vegetation), its importance
as a site of geoheritage signi
ec-
tive of geological processes. The wetlands have been
recognised as of International importance with respect to
their inter-beach ridge setting, their carbonate-rich basal sand
(which in
fl
cance continues to the smallest
scale. Its microscale geology (calcrete, and carbonate grain
dissolution)
and micropaleontology
(pollen,
calci
ed
uences hydrochemical patterns), the archival
information in the Holocene sediments, carbonate muds as
basin
fl
charophyte fructi
cations, and other microbiota) provide
important (metaphoric)
that can be
used to read the history of the Becher Point wetland sedi-
mentary and climate record. In a globally signicant area
such as Becher Point, the pollen and charophyte fructi
letters of the alphabet
lls, the hydrological responses to a varied stratigra-
phy, and the resulting diversity of vegetation. Overall, the
Becher Point Cuspate Foreland and its wetlands represent a
well-documented global example of coastal plain with a
range of multi-disciplinary and inter-related geological
aspects from Holocene beachridge plain development under
progressively changing climate and cyclically changing cli-
mate, with attendant effects on geomorphology, coastal pro-
cesses, hydrology, and sand composition, to wetland
sediments and their evolution, to soil development, intra-
wetland hydrochemistry, hydrological dynamics, diagenesis,
and biodiversity. A selection of geological features of the
Becher Point Cuspate Foreland and its wetlands, graded in
scale, is shown in Fig. 2 .
ca-
tions function as important geological markers within the
Holocene history of the wetlands of the Cuspate Foreland.
Approximately 200 wetlands occur as basins in the inter-
dune depressions of the Holocene beach ridge plain in the
Rockingham area. Eighteen of these were studied in detail in
terms of their landscape setting, stratigraphy, hydrology,
hydrochemistry, and vegetation, (Semeniuk 2007 ). Sixteen of
this group of eighteen were studied further by Semeniuk et al.
( 2006a ) for their pollen record in the surface sediment, and
ve of this group were studied further by Semeniuk et al.
( 2006b ) for their pollen record in the stratigraphic pro
le.
Fig. 2 Biostratigraphy of pollen and charophytes in wetland 161, and
environmental interpretation. The time intervals along the vertical axis
have been arithmetically spaced; as such, the sampling locations at
10 cm intervals between 0 and 95 cm have been adjusted to correspond
to this regular temporal spacing (after Semeniuk 2007 ). Insets of Chara
globularis , Chara brosa , and Baumea articulata shown
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