Camberwell, Dungog & Bulahdelah Explanatory Notes (1991)

Abstract

The regional geology of the Camberwell, Dungog and Bulahdelah 1:100 000 map sheet areas covers mainly Palaeozoic (Devonian to Permian) rocks and the Quaternary igneous and sedimentary units (especially coastal sediments). Discussion is based in part on geophysical studies. Figures, especially stratigraphic columns, and Photographs and other data support the discussion. The area covered by these three maps includes much of the northeastern part of the Sydney Basin, the Gloucester Basin and Cranky Corner Basin and adjacent rocks of the Tamworth Belt. The older rocks (Tamworth Belt) are Devonian to Carboniferous, there being (in these Notes) limited definition of the boundary. Those rocks are, structurally, separated from the Sydney Basin by the Hunter Fault (or Thrust). The Cranky Corner Basin, with rocks to Permian age, rests (perhaps with conformity) on Tamworth Belt units. Similarly, the Gloucester Basin includes Permian rocks, including important coal-bearing units. Discussion in the Notes is centred on structural blocks. Those blocks are, from west to east: Rouchel Block; Gresford Block; Western Myall Block; and Eastern Myall Block. The structure and structural history of those blocks include extensive folding and faulting with broadly north-south trends. Rocks of the Rouchel Block are mainly Devonian (Goonoo Goonoo Mudstone) and Carboniferous marine (with transgressive and regressive episodes) sedimentary units with some extensive volcanic influences. Rocks (Carboniferous) of the Gresford Block are similar, with significant volcanic units, with the Carboniferous to Permian section of the Cranky Corner basin containing some coals. Rocks of the Myall blocks also include correlative Devonian to Carboniferous sections - with the important younger Permian section in the Gloucester Basin including well-developed coal units - albeit with noticeable tilting of the coal in places. Igneous rocks in the area covered include serpentinite, minor granitoids, dolerite 

Reference

Roberts, J., Engel, B., and Chapman, J., 1991. Geology of the Camberwell, Dungog, and Bulahdelah 1:100000 Sheets 9133, 9233, 9333. 382 pp. New South Wales Geological Survey , Sydney.