Mineral transformation during the weathering of dolerite under cold arid conditions in antarctica

Abstract

Chemical weathering taking place in a soil formed on till derived solely from dolerite was investigated. Initially, rock breakdown into smaller particles is by physical weathering. During this process, the ferromagnesian minerals weather chemically, releasing iron and magnesium which recrystallise to form iron-rich montmonllomte In the fine-clay fraction. The silica-rich and chemlcally more resistant minerals accumulate in the silt fraction. Chemical weathering and clay mineral formation in basic igneous rocks in the cold desert environment of Antarctica is similar to that m warmer chmates. These processes can occur whenever temperatures are sufficiently warm to allow the presence of thin films of salt solution around mineral grains, permitting sufficient moisture to be present for chemical transformation to take place. © 1984 Taylor & Francis Group, LLC.