 |
Geology and soils
The topography of the Hunter catchment is strongly controlled by the underlying geology.
A major fault line separates Carboniferous rocks exposed along the northern side
of the catchment, coal measure sequences of Permian age in the central and south-eastern
areas, and Triassic sandstones in the south.
The Carboniferous rocks have been extensively faulted and folded, and form
the steep rugged country leading up to the Barrington Tops. The Permian rock
sequence has been eroded to form the main corridor of the broad Hunter River
Valley. The Permian rocks are derived from ancient marine sediments and contain
salt. Consequently, many streams of the central valley floor are naturally high
in background salinity. A thick Triassic sandstone layer lies over the coal
measures in the southern areas of the catchment, forming a plateau with heavily
dissected tributary valleys.
Soil types are dependent on parent rock type and rainfall levels. Floodplain
soils include alluvials, podzolics and cracking clays.
|
