Explanatory Notes Moss Vale 1 100 000 Geology Sheet 8928

Abstract

These notes provide detailed unit descriptions and a synthesis of the geology of the Moss Vale 1:100 000 geological map sheet area, which lies about 120 km southwest of Sydney and covers parts of the eastern Lachlan Orogen and the overlying southern Sydney Basin. In the area, the oldest rocks of the Lachlan Orogen are strongly deformed, regionally metamorphosed Ordovician deep marine sedimentary rocks. In the west, they are overlain by latest Silurian to Early Devonian, mostly shallow marine, sedimentary and volcanic rocks. A Late Devonian sequence of sedimentary and volcanic rock is preserved in the Budawang Syncline. The orogen contains many Early Devonian and Carboniferous plutons. The Lachlan Orogen rocks are unconformably overlain and largely obscured by the Permo-Triassic sedimentary sequence of the Sydney Basin over much of the map area. This little-deformed sequence dips gently to the north and northeast. Local Cenozoic deposits include basic volcanic rocks, alluvial gravels, soils and alluvium