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The marginal marine deposits signature is evident in the Permo-Triassic basins, the Sydney Basin is not an exception, and has not been subjected to source rock characterisation and petroleum system modelling designed at determining the potentials of hydrocarbon resources and its prospectivity. The economic potentials of the marginal marine environment are great, with enormous information in the literature that deals with the development of these deposits. The wide use of major, trace, and rare earth elements for basin analysis studies to unravel the geochemical signatures of sedimentary succession using the discriminatory diagrams fall short of addressing discriminate sediments from different geotectonic environments consequently a lag in source rock characterisation and petroleum system model of the marginal marine deposits. This review provides new insight into source rock, sediment supply, and depositional patterns of the marginal marine deposits in the Permo-Triassic Sydney Basin and its implication to the dearth in petroleum prospectivity.

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An exposure of agate geode and nodules in Mount Conner, Sabah, provides an essential aspect to the geological formation in Semporna. This paper briefly report results from petrography analyses on the agate geode and nodules and its significance to the volcanic rocks and sedimentary rocks formation in Mount Conner. The geode and nodules can be divided into agate, and nodules and most of them are sub-rounded. Nodules are usually small in size and display brownish colour. It commonly occurs in volcanic rocks (dacite and rhyolite) and contained amygdale filled by secondary mineral such as microcrystalline and macrocystalline quartz. In contrast, sedimentary rocks in Mount Conner contain both nodules and geodes, which nodules shows similar characteristic with nodules in volcanic rocks and geodes contained empty vesicles or spaces surrounded by colourless to milky white quartz crystals. Both geode and nodules exhibit conchoidal fracture, while geode shows vesicle features and nodules in volcanic rocks show amygdale texture. The formation of geodes and nodules in Mount Conner might as result of precipitation under low temperature from hydrothermal solution.