Case hardening of sandstone

Abstract

The case-hardened crust developed on the Aztec Sandstone in the Valley of Fire, Nevada, has been characterized by a variety of techniques, including electron microscopy and infrared spectroscopy. The case-hardened crust consists mainly of host rock, with a fine-grained cement and wind-deposited kaolinite. The cement is usually calcite, but in some cases the hydrated calcium borate, colemanite, was found to be the case-hardening cement