| Abstract: | Petrological studies were carried out on the Upper Cambrian conglomerates from the Bilpa and Cupala Creek areas, in the Wonominta Block, northwestern New South Wales. The sediments are post‐orogenic, molasse‐type, shaped in continental and shallow‐marine environments, and deposited in the form of major coarse‐grained deltas. Diagenetic processes caused an extensive lithification of these psephitic deposits. Multistage carbonate cementation is one of the most significant diagenetic changes that occurred. Several generations of carbonate cements have been distinguished based on observations under the polarising microscope, and particularly, using cathodoluminescence analysis. In both areas studied the conglomerates show four types of calcite cements under cathodoluminescence developed in the following order: non‐luminescent (+oscillatory zoned)‐bright orange‐dull orange‐(non‐luminescent). The most likely sequence of carbonate cementation is presented involving eo‐, meso‐ and telo‐ stages of diagenesis. Minor malachite crystallised along with calcite in the telodiagenetic stage. |
