Geology Reference
In-Depth Information
Table 2
Features of geoheritage signi
cance in Leschenault Peninsula and its leeward lagoon, and the rationale for the assessment
Geological feature
Type of site, and its scale (category of site from
Fig.
1
)
Signi
cance
Rationale for assigning the level of signi
cance
Calcrete in zone of capillary rise
Modern landscapes and setting (active
processes); small to
ne scale feature
International
First and only description to date globally of Holocene calcrete forming in the zone of
capillary rise in relationship to plants
Calcrete at high/low stratigraphic
levels
Geohistorical site; small to
ne scale feature
International
First use of Holocene calcrete to reconstruct Holocene climate history
Calcrete breccia
oatstone
Modern landscapes and setting (active
processes); small to
ne scale feature
International
First description of lenses of Holocene calcrete breccia
oatstone in soils, developed as
a consequence of tree heave by storms
Complex stratigraphy of barrier
Geohistorical site; medium scale feature
International One of the most complex dune barriers stratigraphically in the world because of the
local sea level history superimposed on dune barrier development
Stranded submerged beach rock
forming bands/ridges
Modern landscapes and setting (active
processes), and geohistorical site; medium
to small scale feature
International
First and only description to date globally of stranded beach rock forming submerged
shore-parallel bands/ridges with barrier retreat
Biodiversity of foraminifera
forming rich (neo)
palaeontological assemblage
Modern landscapes and setting; very
ne scale
feature
International
Richest biodiversity of Holocene estuarine foraminifera (neo)palaeontologically in the
world
Linear retrograding barrier
Modern landscapes and setting (active
processes); large to medium scale feature
National
The only linear retrograding Holocene dune barrier barring a barrier-parallel linear
lagoon in Western Australia, and only one of a few nationally; in terms of
sediments, ecology, and hydrology of Leschenault Inlet and the dune barrier are
incomparable to any other system in Australia
Holocene sea level history
recorded in the stratigraphy
Geohistorical site; small scale feature
National
Unique Holocene sea level history recorded in the stratigraphy and reecting local
tectonism
Complex shorelines/stratigraphy
along the dune/estuary
interface
Modern landscapes and setting (active
processes); large to medium scale feature
National
Since the dune barrier is only one of a few occurring Nationally, the complex of
shorelines and stratigraphy at the dune/estuary interface in this climate setting are
Nationally uncommon
Calcite encrustation of sea rush
roots
Modern landscapes and setting (active
processes);
ne to very
ne scale feature
National
Encrustation (and permineralisation) by calcite. Mg-calcite, and dolomite of sea rush
roots in the tidal zone at the dune/estuary interface in this climate setting is
Nationally uncommon
Well-documented Holocene
palynological record as a
model for estuaries
Modern landscapes and setting (active
processes); very
ne scale feature
National
The documented patterns of pollen distribution in the Holocene estuarine sequence
provides model to interpret estuarine palynology
Active parabolic dunes in barrier
Modern landscapes and setting (active
processes); medium scale feature
State-wide/
Regional
The geometry and style of active parabolic dune development within the barrier is
unique in the State; compared with other parabolic dunes that change shape and
orientation with respect to progressively changing wind directions and wind speed
latitudinally (see Semeniuk et al. 1989)
Gradational range of landscapes:
mobile dune to undulating
plain
Modern landscapes and setting (active
processes); large to medium scale feature
State-wide/
Regional
In this climate, with the vegetation contributing organic matter to soils, and the natural
geomorphic gradation from mobile dunes to
xed dunes to plains, this transition is
unique in Western Australia
Calcrete exposed in de
ation
bowls of parabolic dunes
Modern landscapes and setting (active
processes); small scale feature
State-wide/
Regional
Normally, dune bowl excavation proceeds to the water table and forms dune slacks, but
calcrete arrests this excavation; calcrete exposed in bowls is a unique landscape
feature in this calcrete-and-parabolic dune setting in Western Australia
