Coal

Coal is composed of macerated plant remains and minerals. Through the process of burial, these plant remains are transformed into macerals (microscopic constituents of coal) via coalification. The primary factors driving this transformation are temperature, pressure, and time.

Coal can be analyzed based on its properties, such as rank, composition, and grade. These factors, in turn, determine its various applications, including thermal, metallurgical, gasification, and liquefaction processes. Additionally, these properties provide valuable insights into the maturity of the coal, as well as paleotemperatures, sediment accumulation rates, and hydrothermal fluid circulation. This information is essential for basinal studies and resource estimation.

Coal macerals: inertinite (white), vitrinite (grey), liptinite (dark grey/brown). German Creek Coal Measures, Bowen Basin, Australia. Photomicrograph taken in reflected white light.

Coal macerals: inertinite (white), vitrinite (grey), liptinite (dark grey/brown). German Creek Coal Measures, Bowen Basin, Australia. Photomicrograph taken in reflected white light.

Cutinite (from the liptinite group) representing preserved leaves. Walloon Coal Measures, Surat Basin, Australia. Photomicrograph taken in fluorescent mode.

Cutinite (from the liptinite group) representing preserved leaves. Walloon Coal Measures, Surat Basin, Australia. Photomicrograph taken in fluorescent mode.

Exsudatinite filling fractures. It is a indicator of oil generation in coal. In this case, exsudatinite is being generated from resinites. Laura Basin, Australia. Photomicrograph taken in fluorescent mode.

Exsudatinite filling fractures. It is a indicator of oil generation in coal. In this case, exsudatinite is being generated from resinites. Laura Basin, Australia. Photomicrograph taken in fluorescent mode.