Geology Reference
In-Depth Information
well exposed along the southern coast of England, is an
essential feature of the geology of the region of the south-
eastern and southern coast of England, and has geological
characteristics of chalk cliffs, chert nodules, chalk litho
types, chalk diagenesis, Cretaceous shelly fossils, fossil
taphonomy, Cretaceous ichnofauna, Quaternary landforms,
hanging valleys, and shoreline ribbons of
After an assessment of the range, categories, inter-rela-
tionships, and level(s) of signi
cance of the geological fea-
tures, the
nal step is to determine what type and what level
of geoconservation or management the area requires.
4
Case Studies of the Application
of the Geoheritage Tool-Kit in Western
Australia
int-pebble con-
glomerate (Gallois
1965
; Melville and Freshney
1982
;
Brocx and Semeniuk
2010
). In Australia, Shark Bay, a
World Heritage site not replicated elsewhere globally, is a
distinct geological region. Some of its essential features
include its large-scale stratigraphy, the deep-embayed
limestone coastal morphology, seagrass banks, the coquina
deposits, stromatolites, high-tidal crusts, high-tidal gypsum
crystals, gypsum-
Three case studies in Western Australia illustrate the use of
the Geoheritage Tool-kit, wherein inter-related geological
features at various scales are identi
ed and assessed as a
basis for designating geoparks; from north to south, they are:
1. King Sound and the tide-dominated delta of the Fitzroy
River (Semeniuk and Brocx
2011
); 2. the Leschenault
Peninsula and its leeward estuarine lagoon (Brocx and Se-
meniuk
2011a
); and 3. the Walpole-Nornalup Inlet estuary
(Semeniuk et al.
2011
). While each is a coastal area, the
Geoheritage Tool-kit, however, can be applied to any geo-
logical site, or region, to determine its values for geocon-
servation and management.
Figures
2
,
3
and
4
summarise the geoheritage features of
each of the areas, showing the categories of geoheritage
sites, a representative range of geological
lled birradas, modern ooid sand banks,
Pleistocene oolite, and high cliffs cut into Pleistocene
limestone (Logan
1970
,
1974
; Brocx and Semeniuk
2010
).
For the two examples cited above, the geological essentials
tend to be unique and internationally signi
cant and of
geoheritage signi
cance.
An inventory of the geological essentials of a given
region can be compiled using a staged three-pronged
approach to develop a database on the geology, and at the
same time, potentially identifying sites of geoheritage sig-
ni
cance. The three-pronged approach involves drawing on
the experience of geologists as published in the literature,
and/or seeking the views of geologists still practising in the
features at
decreasing scale, and the assessment of signi
cance of each
of the geological essentials.
King Sound and the tide-dominated delta of the Fitzroy
River present geological and geomorphic features of Inter-
national to National geoheritage signi
eld through questionnaires/interviews (providing informa-
tion and personal insights about the geoheritage potential of
an area), and after identifying gaps in information, seeking to
systematically obtain by
cance. Set in a tropical
semiarid climate, the delta of the Fitzroy River has the largest
tidal range of any tide-dominated delta globally. Within King
Sound there are 12 geological features of geoheritage signif-
icance. Some of the key features include: 1) the Quaternary
stratigraphy, with early-Holocene gulf-
eldwork further information based
on regional geology (for instance, an undeformed fossil-rich
or sedimentologically diverse region requires a different
style of
eldwork to a metamorphosed structurally-complex
terrane). For all three approaches, there will be some degree
of overlap in information and outcomes. The staged three-
pronged approach to obtain the essential geological infor-
mation was the approach adopted in Western Australia as
part of the Regional Forests Agreement where sites of
geoheritage signi
lling mud formed
under mangrove cover, followed by middle- to late-Holocene
deltaic sedimentation; and 2) the relationship between Pleis-
tocene linear desert dunes and Holocene sediment that are
globally unique and provide important stratigraphic and cli-
mate history models. King Sound illustrating the principles
underpinning the erosion styles and mechanisms of various
types of erosion (sheet, cliff and tidal creek erosion) com-
bining to develop tidal landscapes and in
cance were determined within a frame-
work in which the
geological essentials
of the region
rst
were identi
ed (Semeniuk
1998
). The Regional Forests
Agreement was an Australian National exercise to determine
the signi
uence (mangrove)
ecological responses (illustrating tidal landscape evolution
determining mangrove response, i.e., an example of geodi-
versity determining biodiversity response), provides a unique
global classroom for such principles and processes. The high-
tidal muddy salt
cance of natural terrains in forested areas, and
assessment of geoheritage values, was part of the evaluation
process (Australian Government
2004
).
The inventory of the geological essentials of a region
forms the basis to identifying the sites of geoheritage sig-
ni
ats have hypersaline groundwater;
responding to this, carbonate nodules of various mineralogy
are precipitated. Locally, linear sand dunes discharge fresh-
water into the hypersaline
cance. The next stage would be to locate good examples,
regardless of scale, of these features, or of inter-related
ensembles of features, and assess them according to the
signi
ats. With erosion, there is wide-
spread exposure of Holocene and Pleistocene stratigraphy,
cance criteria outlined above.
