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Author Hall, S.M.; Gosen, B.S.V.; Paces, J.B.; Zielinski, R.A.; Breit, G.N.
Title Calcrete uranium deposits in the Southern High Plains, USA Type Journal Article
Year 2019 Publication Ore Geology Reviews Abbreviated Journal
Volume 109 Issue Pages (up) 50-78
Keywords Calcrete, Carnotite, Finchite, Geochemistry, Uranium, Vanadium
Abstract The Southern High Plains (SHP) is a new and emerging U.S. uranium province. Here, uranyl vanadates form deposits in Pliocene to Pleistocene sandstone, dolomite, and limestone. Fifteen calcrete uranium occurrences are identified; two of these, the Buzzard Draw and Sulfur Springs Draw deposits, have combined in-place resources estimated at about 4 million pounds of U3O8. Ore minerals carnotite and finchite are hosted in dolomite at the Sulfur Springs Draw deposit, with accessory fluorite, celestine, smectite/illite, autunite, and strontium carbonate. Host carbonate at the Sulfur Springs Draw deposit is ∼190 ka and mineralization mobilized as recently as 3.8 ka. Ash collected near the deposit is 631 ka and erupted from the Yellowstone caldera complex. The Triassic Dockum Group that contains sandstone-hosted uranium deposits throughout the region and underlies the SHP is a potential source for uranium and vanadium. Regional uplift and dissection reintroduced oxygenated groundwater into the Dockum Group, mobilizing uranium. Additional uranium may have been contributed to groundwater by weathering of volcanic ash in Pliocene and Pleistocene host rocks. The locations of the uranium occurrences are mostly in modern drainage systems in the southeast portion of the SHP. Modelling of modern groundwater in the SHP carried out in a parallel study shows that a single fluid could form carnotite through evaporation, and that fluids of the requisite composition are more prevalent in the southern portion of the SHP. The southeastern portion of the SHP hosts more uranium occurrences due to a variety of factors including (1) upward transport of groundwater and connectivity between source and host rock, (2) higher uranium and vanadium content of groundwater, (3) higher rates of groundwater recharge in this region to drive the mineralizing system, and (4) shallower groundwater facilitating surface evaporation. Ongoing erosion of host rocks challenges preservation of deposits and may limit their size.
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ISSN 0169-1368 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number THL @ christoph.kuells @ hall_calcrete_2019 Serial 124
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Author Külls, C.J.; Ritter, M.
Title Deuterium excess anomaly of precipitation in Svalbard Type Conference Article
Year 2010 Publication American Geophysical Union Abbreviated Journal
Volume 2010 Issue Pages (up) 51
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Call Number THL @ christoph.kuells @ Kuells2010deuterium Serial 50
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Author Min, M.; Chen, J.; Wang, J.; Wei, G.; Fayek, M.
Title Mineral paragenesis and textures associated with sandstone-hosted roll-front uranium deposits, NW China Type Journal Article
Year 2005 Publication Ore Geology Reviews Abbreviated Journal
Volume 26 Issue 1 Pages (up) 51-69
Keywords China, Mineralogy, Paragenesis, Sandstone-hosted roll-type uranium deposit
Abstract We present a first paragenetic study of the Wuyier, Wuyisan, Wuyiyi and Shihongtan sandstone-hosted roll-front uranium deposits, northwest China. The mineralization is hosted by Lower–Middle Jurassic coarse- to medium-grained sandstones, which are dark-gray to black due to a mixture of ore minerals and carbonaceous debris. The sandstone is alluvial fan-braided river facies. Minerals associated with these deposits can be broadly categorized as detrital, authigenic, and ore-stage mineralization. Ore minerals consist of uraninite and coffinite. This is the first noted occurrence of coffinite in this type of deposit in China. Sulfide minerals associated with the uranium minerals are pyrite, marcasite, and less commonly, sphalerite and galena. The sulfide minerals are largely in textural equilibrium with the uranium minerals. However, these sulfide minerals occasionally appear to predate, as well as postdate, the uranium minerals. This implies that there are multiple generations of sulfides associated with these deposits. The ore minerals occur interstitially between fossilized wood cells in the sandstones as well as replace fossilized wood and biotite. The deposits are generally low-grade. Primary uranium minerals associated with the low-grade deposits are generally too small, ranging from 0.2 to 0.3 μm in diameter, to be observed by optical microscopy and are only observed by electron microscopy. Mineral paragenesis and textures indicate that these deposits formed under low temperature (30–50 °C) conditions.
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ISSN 0169-1368 ISBN Medium
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Notes Approved no
Call Number THL @ christoph.kuells @ min_mineral_2005 Serial 175
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Author Hebert, B.; Baron, F.; Robin, V.; Lelievre, K.; Dacheux, N.; Szenknect, S.; Mesbah, A.; Pouradier, A.; Jikibayev, R.; Roy, R.; Beaufort, D.
Title Quantification of coffinite (USiO4) in roll-front uranium deposits using visible to near infrared (Vis-NIR) portable field spectroscopy Type Journal Article
Year 2019 Publication Journal of Geochemical Exploration Abbreviated Journal
Volume 199 Issue Pages (up) 53-59
Keywords Coffinite, Mineral quantification, Near infrared, Ore exploration, Portable field spectroscopy, Roll-front deposits
Abstract Coffinite (USiO4) is a common uranium-bearing mineral of roll-front uranium deposits. This mineral can be identified by the visible near infrared (Vis-NIR) portable field spectrometers used in mining exploration. However, due to the low detection limits and associated errors, the quantification of coffinite abundance in the mineralized sandstones or sandy sediments of roll-front uranium deposits using Vis-NIR spectrometry requires a specific methodological development. In this study, the 1135 nm absorption band area is used to quantify the abundance of coffinite. This absorption feature does not interfere with NIR absorption bands of any other minerals present in natural sands or sandstones of uranium roll-front deposits. The correlation between the 1135 nm band area and coffinite content was determined from a series of spectra measured from prepared mineral mixtures. The samples were prepared with a range of weighted amounts of arenitic sands and synthetic coffinite simulating the range of uranium concentration encountered in roll-front uranium deposits. The methodology presented in this study provides the quantification of the coffinite content present in sands between 0.03 wt% to 1 wt% coffinite with a detection limit as low as 0.005 wt%. The integrated area of the 1135 nm band is positively correlated with the coffinite content of the sand in this range, showing that the method is efficient to quantify coffinite concentrations typical of roll-front uranium deposits. The regression equation defined in this study was then used as a reference to predict the amount of natural coffinite in a set of mineralized samples from the Tortkuduk uranium roll-front deposit (South Kazakhstan).
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ISSN 0375-6742 ISBN Medium
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Notes Approved no
Call Number THL @ christoph.kuells @ hebert_quantification_2019 Serial 184
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Author Pavelic, P.; Srisuk, K.; Saraphirom, P.; Nadee, S.; Pholkern, K.; Chusanathas, S.; Munyou, S.; Tangsutthinon, T.; Intarasut, T.; Smakhtin, V.
Title Balancing-out floods and droughts: Opportunities to utilize floodwater harvesting and groundwater storage for agricultural development in Thailand Type Journal Article
Year 2012 Publication Journal of Hydrology Abbreviated Journal
Volume 470-471 Issue Pages (up) 55-64
Keywords Water scarcity, Flooding, Drought, Managed aquifer recharge, Floodwater harvesting, Chao Phraya River Basin
Abstract Summary Thailand’s naturally high seasonal endowment of water resources brings with it the regularly experienced problems associated with floods during the wet season and droughts during the dry season. Downstream-focused engineering solutions that address flooding are vital, but do not necessarily capture the potential for basin-scale improvements to water security, food production and livelihood enhancement. Managed aquifer recharge, typically applied to annual harvesting of wet season flows in dry climates, can also be applied to capture, store and recover episodic extreme flood events in humid environments. In the Chao Phraya River Basin it is estimated that surplus flows recorded downstream above a critical threshold could be harvested and recharged within the shallow alluvial aquifers in a distributed manner upstream of flood prone areas without significantly impacting existing large-medium storages or the Gulf and deltaic ecosystems. Capturing peak flows approximately 1year in four by dedicating around 200km2 of land to groundwater recharge would reduce the magnitude of flooding and socio-economic impacts and generate around USD 250M/year in export earnings for smallholder rainfed farmers through dry season cash cropping without unduly compromising the demands of existing water users. It is proposed that farmers in upstream riparian zones be co-opted as flood harvesters and thus contribute to improved floodwater management through simple water management technologies that enable agricultural lands to be put to higher productive use. Local-scale site suitability and technical performance assessments along with revised governance structures would be required. It is expected that such an approach would also be applicable to other coastal-discharging basins in Thailand and potentially throughout the Asia region.
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ISSN 0022-1694 ISBN Medium
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Call Number THL @ christoph.kuells @ Pavelic201255 Serial 246
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