Unconformity-related uranium

KisterP., CuneyM., Golubev V.N., Royer J.J., LE Carlier de Veslud C., Rippert J.C. 2004. Radiogenic lead mobility in the Shea Creek unconformity-related uranium deposit (Saskatchewan, Canada) migration... 

PoLiTO, P.A., Kyser, T.K., Marlatt, J., Alexandre, P., Bajwah, Z., Drever, G. 2004. Significance of alteration assemblages for the origin and evolution of the Proterozoic Nabarlek unconformity-related uranium deposit. Northern Territory, Australia. Economic Geology, 99, 111-139. 

Rajesh, FI.M. 2008. Mapping Proterozoic unconformity-related uranium deposits in the Rockhole area. Northern Territory, Australia using landsat ETM+. Ore Geology Reviews, 33, 382-396. 

Alexandre, P., Kyser, K., Thomas, D., Polito, P., Marlat, J. 2009. Geochronology of unconformity-related uranium deposits in the Athabasca Basin, Saskatchewan, Canada and their integration in the evolution of the basin. Mineralium Deposita, 44, 41-59. Annesley, I.R., Madore, C., Portella, P. 2005. Geology and thermotectonic evolution of the western margin of the Trans-Hudson Orogen evidence from the eastern sub-Athabasca basement, Saskatchewan. Canadian Journal of Earth Sciences, 42, 573-597. 

Timing, chemistry, and implication of fluids in Canadian and Australian unconformity-related uranium deposits... 

FIecht, L. Cuney, M. 2000. Flydrothermal alteration of monazite in the Precambrian crystalline basement of the Athabasca Basin (Saskatchewan, Canada) Implications for the formation of unconformity-related uranium deposits. Mineralium Deposita, 35, 791-795. 

Wilde, A.R., Mernagh, T.P., Bloom, M.S., FIoffmann, C. 1989. Fluid inclusion evidence on the origin of some Australian unconformity-related uranium deposits. 

Cumming, G. L. Krstic, D. 1992. The age of unconformity-related uranium mineralization in the Athabasca basin, northern Saskatchewan. Canadian Journal of Earth Science, 29, 1623-1639. 

Unconformity-related uranium Athabasca district Saskatchewan, Canada Deep groundwater flow related to faulting Mixing of oxidizing uraniferous and reducing waters... 

Exploration for economic uranium deposits has expanded to many geologic environments that have been generally overlooked in the past. Most notable among these are (1) granitic uranium deposits, (2) alkalic igneous-hydrothermal uranium deposits, (3) altered acidic or alkalic volcanic ash, ash flow or volcaniclastic uranium deposits, (4) unconformity-related uranium deposits and (5) calcrete uranium deposits in desert groundwater environments. 

Vein-like deposits in metamorphic rocks also occur in Pre-cambrian Shield areas, but they differ from unconformity-related uranium deposits in that they are not associated with major regional unconformities, the geometries of orebodies are different and they extend to greater depths. Vein-like deposits are closely associated with steeply dipping, brecciated major fault systems. Uranium minerals (pitchblende with some coffinite and brannerite) occur as open fracture fillings and as fine disseminations adjacent to the fractures in Proterozoic meta-igneous andmetasedimentary rocks. Common associated minerals are chlorite, hematite and pyrite. 

Rabbit Lake, northern Saskatchewan, Canada The Rabbit Lake occurrence in northern Saskatchewan is an example of a monometallic unconformity-related uranium deposit. 

The U/ U ratios of uranium minerals from volcanic-, metasomatic-, unconformity- and sandstone-related uranium showings and deposits worldwide measured by multi-collector ICP-MS indicate a total variation in values of... 

The uranium oxides from the Eagle Point and Millennium deposits have bellshaped REE patterns centred on Tb or Dy, typical of unconformity-related deposits (Pagel et al. 1987 Fayek ... 

Unconformity-related U deposits account for more than 33% of the world uranium resource due to their tremendous grade and tonnage. Most of them occur in the McArthur Basin (Northern Territory, Australia) and in the Athabasca Basin (Saskatchewan, Canada). The ore is commonly found close to the interface between Archaean to lower Proterozoic metamorphic and plutonic rocks, and unconformably overlying Proterozoic sandstones. Basement-rooted graphitic reverse faults are also important structural controls. 

Unconformity-related deposits are found near principal unconformities. Examples include the ore bodies at Quff Lake, Key Lake, and Rabbit Lake in northern Saskatchewan, Canada, and in the Alligator Rivers area in northern Australia. Sandstone deposits are contained in rocks that were deposited under fluvial or marginal marine conditions. The host rocks nearly always contain pyrite and organic plant matter. The sediments are commonly associated with tuffs. Unoxidized deposits of this type consist of pitchblende and coffinite in arkasoic and quartzitic sandstones. Upon weathering, secondary minerals such as camotite, tuyamunite, and uranophane are formed. More information on these and other uranium deposit types is available (1). 

Vein-like deposits were described as uranium deposits of uncertain genesis by Mathews etal Except for a small number of these deposits in sedimentary rocks, the group is subdivided into unconformity-related deposits and deposits of metamorphic rocks. In a more genetic classification of the major (Proterozoic) vein-like deposits of the world, Dahlkamp and Adams deciphered the relationship of diagcncsis, metamorphism, metasomatism and weathering on uranium concentrations in various host rocks. The result is a logical genetic explanation for the spectrum of vein-like deposits observed today. 

The most important uranium deposits in rocks of this age are those of the unconformity-related type. These deposits are found principally in the East Alligator River area, N.T.,... 

Much of the world s currently minable uranium is found in vein-like deposits of uncertain origin. They consist of three general types of unequal importance. Most important are unconformity-related deposits and vein-like deposits in meta-morphic rocks. Least important and probably of different origin are vein-like deposits in sedimentary rocks. The origin of all three types is a matter of much conjecture. Major unsolved genetic questions are the source of the uranium and its mode of transport, the source of the mineralizing solutions, the nature and role o f reductants and the control exerted on uranium deposition by structural and lithologic features of the host rocks. Unconformity-related deposits and vein-like deposits in metamorphics commonly occur in brecciated and foliated metamorphic rocks in stable Precambrian Shield areas. They contain about 24.4% of the Western world s reasonably assured 30 uranium resources. 

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