An experimental study of metal extraction from red-bed sandstones as potential source rocks for sediment-hosted copper deposits

Understanding the extraction, transport and deposition of metals to form ore bodies in sedimentary basins is important because basin-hosted copper deposits host more than 23 % of the world's discovered copper as well as other metals such as vanadium and cobalt. These critical metals are key for the ongoing energy transition. Red bed sandstones have been identified as potential metal sources for sedimentary basin-hosted copper deposits because they are typically found in copper-bearing basins and their iron oxide coatings can adsorb metals. Thus, dissolution of these coatings could lead to the formation of an ore fluid. However, previous experiments to understand the extraction and mobility of copper and other trace metals in sedimentary basins have not considered flow effects, elevated temperatures, or natural brine compositions. Here, we report new experiments to quantify the release of metals from red bed sandstones in contact with: (i) aqua regia; and (ii) a variety of natural brines over a range of temperatures.