Geochemistry of Silica Rocks in the Drummond Basin as a Record of Geothermal Potential

Abstract

Silica is the most abundant mineral in the Earth’s upper crust; yet its trace element composition has not been utilised routinely in the exploration of natural resources. Siliceous sinters are pristine rocks that precipitate at the surface from spring waters heated by deep-seated magma chambers. They can be useful indicators of hot radioactive magmatic basements in sedimentary basins. However, distinguishing silica sinters from other siliceous lithologies is often ambiguous because siliceous lithologies of various origins occur ubiquitously on the ground surface as rock chips or soil material eroded from deeper geological units. In this study, we characterise trace element compositions of silica sinters to provide geochemical criteria for exploration of geothermal energy sources. We investigated silica sinters and the associated hydrothermal quartz veins, volcanic rocks, silicified hydrothermal breccias, alteration minerals, and some soil samples from the Paleozoic Drummond Basin, Australia by ICP-MS trace element analysis.