Laboratory, field, and computer flow study of the origin of Colorado Plateau type uranium deposits

Abstract

Despite considerable scientific research over the past twenty-five years there still remains much speculation and uncertainty concerning the origin of the so-called tabular uranium deposits of the Colorado Plateau. One particular hypothesis suggests that the deposits resulted from geochemical reactions at the interface between a relatively stagnant solution and a dynamic, ore-carrying solution which permeated the host sandstones. The present study was designed to investigate some aspects of this hypothesis, notably the nature of fluid flow and the relations between the ore deposits and the host sandstones.Field studies involved an investigation of the character and origin of the host fluvial sandstones and their contained uranium deposits and an examination of the textural and porosity-permeability patterns in similar Holocene fluvial sand bodies. Data from the Holocene sand bodies was used to construct realistic porous media models. These models were then saturated with a humic acid solution andean aluminum potassium sulfate solution, causing a visible humic acid precipitate to form at the interface of the two fluids. Finally, an existing numerical model was modified and calibrated for use in predicting the shape and location of the interface between the two solutions.

Quantification of a Distributive Fluvial System: The Salt Wash DFS of the Morrison Formation, SW U.S.A.

“…Meandering elements, either minor or large, have been previously noted in various parts of the system by Fischer and Hilpert (1952), Stokes (1954), Peterson (1977), LeBaron (1980), Peterson (1984), and more recently Holzweber (2013) and Owen (2014). We suggest that the previous emphasis on interpretations as braided stream deposits is misplaced, a viewpoint shared by Ethridge et al (1980), and we interpret the sandy characteristics to be a function of the low accommodation/sediment supply (A/S) regime that persisted in the basin, a view echoed by Kjemperud et al (2008). Amalgamated channel-belt deposits constitute 37% of all sections logged.…”

Geology and recognition criteria for uraniferous humate deposits, Grants Uranium Region, New Mexico. Final report

“…The labile nature of both the volcanic source material and the organic acids also support the idea of a very early age for the ore-forming process. This organic model is simple and lends itself to easy laboratory confirmation (Ethridge et al, 1980). The real problem is explaining how such large deposits of humate, such as those found in Ambrosia Lake, form.…”

Depositional Setting of the Salt Wash Member of the Morrison Formation, Southwest Colorado

“…These data were used to reconstruct the three-dimensional architecture of the fluvial sediments. Preliminary results were Mullens and Freeman, 1957). reported by Tyler and Ethfidge (1980) and Ethridge et al (1980). STRATIGRAPHIC SEI'rlNG The Jurassic Salt Wash Member of the Morrison Formation has a well-defined fan-shaped geometry (Craig et al, 1955).…”