Paleovalley-related uranium: exploration criteria and case-studies from Australia and China

Abstract

layers often form the upper and lower bounding strata of individual deposits. Uranium deposits are associated with reduced lithologies; mineralisation is developed where oxidising fluids (carrying dissolved U) were modified by interaction with reduced sands, the latter commonly containing pyrite and dispersed organic matter and/or seams of lignite. Mineralised bodies, often tabular or roll-shaped, formed along the interface between clay horizons and the sandy facies of paleovalley sediments. Geological, geophysical and geochemical features of the paleovalleys and related uranium deposits have been used to construct models to understand ore genesis and assist exploration for paleovalley-hosted uranium deposits. Australia and China remain highly prospective for the discovery of new paleovalley-related uranium deposits. The precise geometric definitions of the basin margin and paleovalley architecture are important in identifying exploration targets and improving the effectiveness of drilling. This requires the integration of various geoscientific data sets. Refinements in remote sensing, geophysical techniques and data processing, in combination with sedimentological and depositional interpretations, provide an efficient approach for outlining the principal drainage patterns and channel dimensions. To help reduce risk, an exploration strategy should combine these technologies with a detailed understanding of the physicochemical parameters of uranium reduction, mobilisation and preservation.

Modeling the connections between internally and externally drained basins using GIS, Google Earth©, and remote sensing

“…Lakes in the Victoria River DDN. Australia's lakes are useful analogues for Pleistocene hydrologic change and evaporite formation, offering the potential for long records of palaeohydrologic changes, and are also potential sources of mineral commodities (Bowler, 1986;Magee, 2013;Hou et al, 2014;Mernagh et al, 2016). The Australia geosciences surface hydrology database (Geoscience Australia, 2018b) shows 146 named and 4867 unnamed lakes in the Victoria River DDN, of which only about 6% are perennial.…”