Download or read book Lithostratigraphic and Structural Controls of Uranium Mineralization in the Kiggavik East Zone Centre Zone and Main Zone Deposits Thelon Basin Nunavut written by Dillon Daniel Johnstone and published by . This book was released on 2017 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Kiggavik uranium deposits are located in the north-central Rae Subprovince of the Western Churchill Province and are hosted in highly deformed Archean and Paleoproterozoic basement rocks proximal to, and underlying the Thelon Basin. This field-based study documents the lithostratigraphic and structural character of Kiggavik's basement rocks and their controls on the uranium deposits. Field investigation, coupled with structural analysis, geochemistry and geochronology indicates that the basement rocks comprise two main tectonostratigraphic packages: a structurally 'lower-package' comprising ~2.71 Ga Pipedream assemblage metagreywacke and a structurally 'upper-package' consisting of multiple intervals of ~2.6 Ga Snow Island Suite felsic epiclastic and metarhyolite intercalated with less than 2.3 Ga quartzite of the Ketyet River group. Of particular significance are the epiclastic rocks, which, based on their textural variability, felsic composition, negative europium anomaly and association with metarhyolite, are correlated with previously identified epiclastic volcanic rocks in the western part of the area, rendering this the most spatially extensive rock unit at Kiggavik. Further, field investigation, coupled with structural analysis, confirms that all units form a homoclinal sequence that dips gently NNW in the eastern map area (Domain 1) and ENE in the western map area (Domain 2). Based on regional stratigraphic relationships, down-section profiles in both domains contain multiple younging direction reversals. This, coupled with strongly transposed bedding, ubiquitous foliation and highly strained contacts, plus the direct observation of isoclinal, recumbent folds in both outcrop and drill core, indicates that these repetitions are tectonic. In addition, across both domains, all units carry a well-developed stretching lineation. The collective 3D geometry and associated fabric elements are diagnostic of sheath folding and related thrusting under an ENE-WSW tectonic transport direction during DP1 when the upper (epiclastic-metarhyolite-quartzite) package is interpreted to have been translated over the more competent metagreywacke below. Although once misunderstood, the difference in dip direction between domains is ascribed to a domain-bounding NNW-trending fault that misoriented blocks, causing late-stage dragging and down-dropping of all units in the east during late, dip-slip motion along the Thelon Fault. In general, late brittle deformation is manifested by ENE-trending regional-scale Group 1 faults and local-scale Group 2 faults that collectively define a Riedel shearing system driven by dextral strike-slip displacement along the Thelon Fault. Detailed study at the Centre Zone deposit revealed that during Phase 1 mineralization steeply dipping D- and P-shears served as conduits for fluids to move through and penetrate earlier-formed ductile structures. The fluids preferentially infiltrated through, and precipitated uranium in, the more porous-permeable epiclastic and metagreywacke, while the quartzite served as an overlying aquitard. Phase 2 mineralization resulted from the reactivation of these structures, when remobilizing fluids redistributed uranium along planar brittle structures. In addition to the Hudson and Kivalliq granites, felsic Snow Island Suite rocks may have also been a significant source of uranium.

Download or read book Structural Control of Mineral Deposits written by Alain Chauvet and published by MDPI. This book was released on 2019-04-16 with total page 256 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Structural Control” remains a crucial point that frequently lacks in any scientific and/or economic analysis of ore deposits, whatever their type and class. The case of lode deposits is exemplary, although also other deposits, like breccia pipe, stockwerk, massive sulphides, skarn, etc., can, surprisingly, be concerned. Several concepts like the gold-bearing shear zone have not proven valid during the last few decades in terms of our understanding of gold deposit and have been totally abandoned. Additionally, the relationships between magmatism, regional tectonic context, and mineralization remain uncertain and have been debated in several recent publications. This demonstrates that this issue is still relevant, and its solution may help in the distinction between intrusion-related and orogenic deposits. In this Special Issue, we particularly invite any case study of mineral deposits, in which it has been demonstrated that structural geology may have a significant role in the establishment of the deposit model of formation and/or on exploration and exploitation programs. Examples in which the structural model diverges from those described in the classical literature are particularly welcomed, including studies in which relationships with magmatism can be suspected and/or demonstrated. Indeed, all cases that illustrate concepts that differ from the classic ones and from theoretical models may represent significant contributions to this volume.

Download or read book Fluid Evolution and Structural Control on Uranium Deposits in Successor Basins in Northern Canada and Northern Australia written by Serigne Dieng and published by . This book was released on 2012 with total page 554 pages. Available in PDF, EPUB and Kindle. Book excerpt: Uranium deposits associated with Paleoproterozoic successor basins were investigated using structural, petrographic, geochronological and geochemical relationships to understand the character and timing of ore-forming fluids and the structural control on uranium mineralization. The work focused on two successor basins that share similar geological characteristics: the Martin Lake Basin in the Beaverlodge area in Canada, and the El Sherana Basin in the South Alligator River area in Australia. The Beaverlodge area records six temporally distinct stages of U mineralization spatially associated with the Martin Lake successor basin. Early minor stages are hosted in cataclasite and veins at ca. 2.29 Ga and in albitized granite in the Gunnar deposit between ca. 2.3 Ga and 1.9 Ga, which predates the main stage of U mineralization of hydrothermal breccias that formed at ca. 1.85 Ga. Later stages of mineralization are related to minor veins at ca. 1.82 Ga linked to alkaline mafic dikes associated with the Martin Lake Basin and to minor veins at ca. 1.62 Ga corresponding to the timing of unconformity-type U mineralization in the overlying Athabasca Basin. The main breccia-type U mineralizing event that affected all deposits in the Beaverlodge area formed at ca. 1.85 Ma from metamorphic fluids at ca. 330oC linked to metasomatism during regional metamorphism of the Trans-Hudson Orogen. The ore-forming fluids were likely derived from metamorphic remobilization of pre-existing U-rich basement rocks, and ascended upward along deep fracture systems that resulted from brittle reactivation of early ductile shear zones. The main event of U mineralization in the South Alligator River area formed at ca. 1.82 Ma, subsequent to deposition of the El Sherana Group at 1.84-1.83 Ma. The formation of these deposits is related to fluids derived from diagenetic processes in sandstone of the El Sherana Group. Mineralization formed when a 250oC, low latitude, oxidizing, U-bearing basinal brine from diagenetic aquifers in the Coronation sandstone descended downward into the unconformity along fracture systems created by brittle reactivation of the El Sherana-Palette fault system. Uranium deposits associated with successor basins in the Beaverlodge and South Alligator River area are older than those in the U-rich Athabasca and Kombolgie basins. Rocks that host these deposits have been folded, and then exhumed during subsequent tectonic events. These older U deposits can be considered as a potential source for detrital uraninite that fed sediments of the Athabasca and Kombolgie basins and therefore contributed to the inventory of uranium that formed unconformity-related U mineralization in the younger basins. Therefore, the occurrence of older U mineralization associated with successor basins can be considered as positive criterion for exploration of unconformity-related U mineralization in younger Paleoproterozoic basins.

Download or read book Fingerprinting and Tracing the Signature of Basement hosted Unconformity type Uranium Alteration Through Thick Quaternary Tills written by Aaron Bustard and published by . This book was released on 2016 with total page 216 pages. Available in PDF, EPUB and Kindle. Book excerpt: The question of whether or not it is possible to trace the signature of alteration haloes surrounding deep-seated unconformity-type U mineralization through thick Quaternary tills is one of great importance for those conducting exploration in glaciated areas. The geochemical signals associated with alteration are often subtle and subject to numerous sources of noise, and multi-till stratigraphies can completely mask or truncate dispersal patterns. To study glacial dispersal from alteration zones surrounding unconformity-type uranium mineralization, this study focuses on a deep-seated (>100 m) basement-hosted unconformitytype U mineralized body known as Tatiggaq, which is located in the Thelon Basin of Nunavut. The Tatiggaq area presents an ideal opportunity to investigate this problem, since the area is blanketed by a thick (12-34 m) multi-till stratigraphy, mineralization does not intersect the bedrock-till interface, and the mineralization is surrounded by an extensive illitic alteration halo that reaches the bedrock surface. The recovery of till samples from diamond drill core from the multi-till stratigraphy overlying the subcropping alteration halo provides a unique opportunity to model glacial dispersal and identify whether the fingerprint of buried alteration can be traced through three dimensions to the modern day surface. Sampling of till recovered during diamond drilling was combined with the sampling of surficial mudboils in the area surrounding Tatiggaq to trace the dispersal of alteration. The drill core samples were collected from four stratigraphic units that were deposited by early southwesterly and southerly ice flows, followed by a reversal in ice flow towards the northwest and westnorthwest. Knowledge of the till stratigraphy directly above the Tatiggaq alteration zone was used to construct a three dimensional model of the sediments overlying bedrock to allow the tracing of alteration through the subsurface. The geochemical fingerprint of the alteration halo at Tatiggaq was identified by applying univariate and multivariate statistical analysis, including principal component analysis, to geochemical data from altered and fresh rocks in the region. This analysis identified the enrichment of Fe2O3, K2O, Al2O3, P2O5, TiO2, B, Ni, U, Cr, and Sc, and depletion of CaO, MnO, Na2O, Mo, Zn, Ba, and Sr in the altered rocks using total digestion of rock powders (HF-HClO4-HNO3). Partial digestion of the same rock powders using HNO3-HCl identified the enrichment of U and depletion of V, Zn, Y, and Yb in the altered rocks. The observed trends in the bedrock data were then applied to the till geochemistry data to identify alteration signatures that were discernible across the till stratigraphy.

Download or read book Some Stratigraphic Sedimentary and Structural Relations of Uranium Deposits in the Salt Wash Sandstone written by William Lee Stokes and published by . This book was released on 1954 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt: Under contract between the University of Utah and the U.S. Atomic Energy Commission, the writer has carried on a field and laboratory investigation of the uranium deposits in the Salt Wash sandstone of the Colorado Plateau.

Download or read book Investigating Modelling and Inversion Techniques for Overburden Stripping for Uranium Exploration in the Athabasca Basin Canada written by Mahrdad Darijani and published by . This book was released on 2020 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The major investment in exploration for uranium in Canada is in one of the most important structural corridors of the eastern Athabasca Basin, extending from the Millennium deposit to the McArthur River deposit (called the McArthur-Millennium corridor). This corridor hosts the largest and highest-grade uranium deposits in the world (at a depth of more than 500 m), and it will be the focus of exploration activity by companies (e.g., Cameco) in the Athabasca Basin for many years. In the McArthur-Millennium corridor, people have wondered about how to better detect structures (e.g., alteration zones) associated with the (volumetrically) small uranium mineralization at depth using geophysical methods. But the geophysical responses (e.g., the gravity response) of these structures can be masked by the variation of the overburden thicknesses. Some geophysical attempts have been made to remove the overburden signature and to find the alteration zones, but none of them have got very far. To solve this problem, I investigate developing new methodology as well as new exploration methods in the region to find and remove the overburden signature to explore for new deposits. In this dissertation, I investigate new ways to separate the overburden contribution from geophysical data (via modelling and inversion) so that deeper targets (e.g. an alteration zone) can be detected and delineated by means of an innovative application of new, modern, state-of-the-art modelling and (constrained and joint) inversion of geophysical methods such as seismic refraction, gravity, magnetic and electromagnetic methods. These new methods and investigations (e.g., modelling and constrained joint inversions using the fuzzy c-mean method on tetrahedral meshes) bring us much closer to solving the problem in this corridor. This research project is a part of the CMIC Footprints project, and is a very challenging exploration problem and very useful if successful for many places in Canada, not just the Athabasca Basin and uranium exploration. The Athabasca Basin is a Proterozoic sedimentary basin which supplies around 20% of the world's uranium. The uranium deposits are surrounded by alteration zones near the unconformity between Proterozoic sedimentary rocks and the Archean and Aphebian metamorphic basement. The sedimentary rocks are covered by Quaternary glacial deposits. Because of the small size of uranium deposits and their location at depth, geophysical methods look for structures which host the uranium deposits, for example, electromagnetic (EM) methods can locate graphitic faults. The gravity method can potentially detect the alteration zones. The seismic method can image the unconformity and basement faults. And, magnetic data can delineate basement structures. The benefit of using multiple datatypes can provide complementary information (e.g. the seismic and gravity). These methods can be used for the overburden stripping as well. In the Athabasca Basin, overburden can be conductive while density and seismic velocity of the overburden is less than the sandstone. Some rocks in unconsolidated glacial deposits have magnetic susceptibilities (e.g. granite), whereas sandstone is non-magnetic. Based on these features, the synthetic modelling and inversion of the geophysical data are performed for (mainly) the overburden characterization as well as reconstructing the geological structure in depth. Magnetic, gravity, first-arrival seismic traveltimes and time- and frequency-domain electromagnetic data are synthetized using forward modelling of 2D and 3D models. For inversion methods, independent, joint and constrained methods are applied for 1D, 2D and 3D cases. Independent inversions of the seismic refraction data as well as the electromagnetic data are useful methods for reconstructing the base of the overburden, unlike the independent inversions of gravity and magnetic data. The joint inversion of gravity and seismic refraction data is able well to reconstruct the variable thickness of the overburden better and sharper than the independent inversions. After applying the thickness of the overburden (obtained from the joint inversion) in the constrained independent inversion of gravity data, the location of alteration zone is apparent at depths. The joint inversion of magnetic and gravity data was able to reconstruct the basement blocks, the sandstone and the unconformity; furthermore the base of overburden can be detected after using the constrained joint inversion of magnetic and gravity methods. This method cannot show the alteration zone, but it can show the intersection of the fault with the unconformity where the mineralization can occur. For the electromagnetic method, results show that frequency and time-domain methods can be used for determining the location of the interface between overburden and sandstone and the location of the graphitic faults, respectively.

Download or read book Stratigraphic and Structural Controls of Uranium Deposits on Long Mountain S Dak written by W. A. Braddock and published by . This book was released on 1957 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Geological Comparison Between East European and Canadian Uranium Deposits written by V. Ruzicka and published by . This book was released on 1971 with total page 222 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Relation of Uranium Deposits to Feeder Structures Associated Alteration and Mineral Zones written by and published by . This book was released on 1958 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt: Minerals districts in southwestern Colorado commonly contain a central altered area enclosed by irregular zones containing different metal deposits, including uranium. The central altered area is essentially a high-angle ''pipe'' which encloses a portion of a major fault zone, or an igneous contact, or is apparently not associated with any major structure. Alteration occurs in all rock types although it is selectively stronger in the metamorphic basement rocks and the intrusives of Tertiary age. Alteration, in paragenetic sequence, is commonly of the argillitic, sericitic, silicic, and pyritic types. In intensely mineralized districts, veins and replacement bodies occur principally marginal to the central, pervasively altered area, in ground altered only in the wall zones of larger fissures. Deposits within the central altered area are principally replacement disseminations. Types of metal deposits are generally grouped along preferred structural weaknesses according to distance from the central alltered area. Each group defines a zone, partially concentric about a central area. The central alteration pipe is interpreted as the principal feeder channel for the district and represents the most permeable locality prior to mineralization. Early alteration products are believed to have sealed this permeable area near the surface, forcing later metalilizing solutions from the central channel at depth to less permeable available marginal channels. Later solutions rose through successively more distant channels, unless inner channels were reopened or incompletely sealed. In the western Colorado metallogenic province uranium occurs within some central alteration pipes, possibly as a lattice constituent in iron sulfide. Deposits contain less than 100 tons of rock containing 0.03% U/sub 3/O/sub 8/. Uranium occurs in base-metal zones as pitchblende, commonly associated with copper. Here deposits are less than 1000 tons of 0.1% U/sub 3/O/ sub 8/ material. Commercial uranium deposits occur on the outer margin of the gold zone, where deposits may be about 50,000 tons of 0.5% U/sub 3/O/sub 8/ ore. Many alteration pipes in the southern Colorado Plateau enclose collapsed breccia or collapsed-plug pipe structures which contain no volcanic material, but which are interpreted as cryptovolcanic structures. Many of these pipes are mineralized by uranium. Several, having a magnitude order of 30,000 tons of 0.5% U/sub 3/O/sub 8/ ore per pipe, are known. These pipes are interpreted as possible central feeder structures for districts where the ore is of hydrothermal origin. Such pipes may not only contain uranium deposits but may also have supplied laterally migrating solutions from which outlying sandstone impregnations were deposited. (auth).

Download or read book Geology and Recognition Criteria for Uranium Deposits of the Quartz pebble Conglomerate Type written by A. Button and published by . This book was released on 1980 with total page 396 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Geological Classification of Uranium Deposits and Description of Selected Examples written by International Atomic Energy Agency and published by . This book was released on 2018 with total page 430 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Stratigraphic and Structural Controls of Uranium Deposits on Long Mountain South Dakota written by William A. Braddock and published by . This book was released on 1957 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Stratigraphic and Structural Controls of Uranium Deposits on Long Mountain South Dakota written by Donald Albert Brobst and published by . This book was released on 1957 with total page 64 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Stratigraphic and Structural Controls of the Uranium Deposits on Long Mountain Fall River County South Dakota written by William A. Braddock and published by . This book was released on 1954 with total page 46 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Unconformity Related Uranium Deposits written by International Atomic Energy Agency and published by . This book was released on 2018-12-31 with total page 308 pages. Available in PDF, EPUB and Kindle. Book excerpt: This publication provides a description of existing and emerging technologies to effectively integrate geological, geophysical and geochemical data to recognize the footprint (i.e. the total extent that the mineralizing system has affected its environment) of the deposit and the key vectors to the uranium mineralization. In addition, insights into exploration strategies and risks associated with country and basin selection are discussed, including the role of the IAEA and academia in supporting the exploration process. Representing an unprecedented, comprehensive reference document on unconformity-related uranium deposits with over 350 citations, this publication will be useful for decision makers at all levels, including governmental officers in energy and mineral resources, exploration companies, geologists, geological surveys, energy companies, universities and research institutions, and natural resource authorities.

Download or read book Stratigraphic and structural controls of uranium deposits on Long Mountain South Dakota written by William A. Braddock and published by . This book was released on 1957 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Unconformity related Uranium Deposits written by International Atomic Energy Agency and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: