10.80350/TEST_DOI_5E589CA183C5C
Geological Survey of New South Wales
1994
Text
0155-3410
Palaeozoic stratigraphy of the Narromine 1:250 000 sheet area
1994-07-01
Sherwin L.
Quarterly Notes of the Geological Survey of New South Wales
The western third of the area covered by the Narromine 1:250 000 geological map has rocks of the multiply deformed Girilambone Group as basement. Part of the Girilambone Group has been differentiated as the Tottenham Subgroup, possibly of volcanic origin, which contains the distinct lithologies recognised as the Mount Royal Schist, Bogan Schist and Carolina Forest Formation. The eastern two thirds of the sheet area has a less deformed basement, separated from the Girilambone Group by the north-south Fifield/Steeton fault system. This less deformed basement comprises mostly Late Ordovician trachyandesitic volcanics and quartzose sediments. In the east, between the Parkes Thrust system and the Coolac-Narromine Suture, it is strongly cleaved. There are hiatuses in the geologic record between the Early and Middle Silurian, within the Late Silurian and Early Devonian, at the end of the Early Devonian and possibly between the Middle and Late Devonian. Siliceous volcanism was widespread in the Late Silurian - Early Devonian but was comparatively restricted in the late Early Devonian and Middle Devonian. Granites in the area were intruded both in the Early Devonian and at about the Middle to Late Devonian.