Mittagong Formation

Mittagong Formation

Stratigraphic range: Triassic
TypeGeological formation
UnderliesAshfield Shale
OverliesHawkesbury sandstone
Thicknessup to 10 metres (30 ft)
Location
LocationSydney Basin
CountryAustralia
Type section
RegionMittagong
CountryAustralia
Thickness at type section15 metres

The Mittagong Formation is a sedimentary rock unit in the Sydney Basin in eastern Australia.[1]

Formation

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Laid down in the Triassic Period, it may be seen as an interval of interbedded fine-grained sandstone and shale between the Ashfield Shale (above) and the Hawkesbury sandstone (below). The maximum thickness around Sydney may be ten metres.[2] Near Town Hall railway station, the formation is 8 metres thick. In the type area at Mittagong it is 15 metres thick.

Whereabouts

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In northern Sydney it can be seen in several areas, such as West Pymble[3] and Mount Ku-ring-gai.[4] This rock formation is associated with the critically endangered Sydney Turpentine-Ironbark Forest.[5]

See also

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References

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  1. ^ "Australian Museum - The Sydney Basin".
  2. ^ "Geoscience Australia".
  3. ^ Field Geology of New South Wales, Sydney Basin page 102
  4. ^ Chris Herbert. Geology of the Sydney 1:100,000 Sheet 9130
  5. ^ "Sydney Turpentine-Ironbark Forest".