Uranium occurrence

Intrusive Deposits. Deposits included in the intmsive deposit type are those associated with intmsive or anatectic rocks of different chemical composition, eg, alaskite, granite, monzonite, peralkaline syenite, carbonatite, and pegmatite. Examples include the uranium occurrences in the porphyry copper deposits such as Bingham Canyon and Twin Butte in the United States, the Rossing Deposit in Namibia, and Ilimaussaq deposit in Greenland, Palabora in South Africa, and the deposits in the Bancroft area, Canada (15). 

The geological term, uranium occurrence, implies a naturally occurring anomalous concentration of uranium. The term, uranium deposit, implies a mass of naturally occurring mineral material from which uranium could be exploited at present or in the future. An often-encountered term in uranium mineralogy is uranium ore mineral. It is a mineral having such physical and chemical properties and occurring in a deposit in such concentra-... 

Intrusive Rossing deposit in Nambia, uranium occurrences in porphyry copper deposits as Bingham Canyon and Twin Buttle in USA, the Palabora in South Africa, deposits in the Bancroft area, Canada. 

The Horton Group rocks of the Maritimes Basin are hosts to the best documented uranium occurrences (Quarch et a/.1981). The Horton Group can be divided into the upper arkosic Cheverie Formation and the lower Horton Bluff Formation. 

Fig. 1. Location of uranium occurrences in granitoids and the Horton Group in Atlantic Canada.

The initial exploration and subsequent drilling in the Windsor area was sparked by the discovery of radon anomalies in the soil gas and well waters in the area (Quarch et al. 1981 Fig. 2). In addition, uranium and radium in well waters were weakly anomalous in the area. It is therefore not difficult to infer that these geochemical techniques are useful exploration tools for deposits of this type and that there are environmental Issues related to uranium occurrences in the Horton Group. 

Ryan, R.J. O beirne-Ryan, A.M. 2007. Preliminary report on the origin of Uranium Occurrences in the Horton Group of the Windsor area. Nova Scotia. In Mineral Resources Branch, Report of Activities 2006, Edited by D.R. MacDonald. Nova Scotia Department of Natural Resources, Report 2007-1, 137-157. 

Hills, which are a component of the Western Carpathian Range. The mountain range at Kuriskova is composed of mesozonal to epizonal metamorphic rocks knowm as the Gemericum tectonic unit of the Carpathian belt. There is a nearly continuous, 0.5 to 6.0 km wide and 80 km long zone of Permian rocks along the northern periphery of the tectonic unit in which there are numerous uranium occurrences. 

Fig.1. The Central Mineral Belt of Labrador and its principal uranium occurrences.

Gandhi, S.S. 1978. Geological setting and genetic aspects of uranium occurrences in the Kaipokok Bay - Big River area, Labrador. Economic Geology, 73, 1492-1522. 

Harvey a volcanic-hosted Uranium occurrence at the edge of the... 

With atomic number 92 and atomic weight 238.03, uranium is the heaviest naturally occurring element. There are eleven known isotopes, of which three — with atomic weights 234, 235 and 238 — occur in nature. They are all radioactive, with half-lives (in years) of 2.35 X 10 , 7 X 10 and 4.5 X 10 , respectively. The relative abundance of the isotopes varies depending on the age and geological history of the uranium occurrence a typical distribution is U 99.28% U 0.71% U 0.005%. A quite exceptional deviation from this distribution has been found at Oklo in Gabon as a result of spontaneous fission chain reactions in the remote past (Anon., 1975). At Oklo U concentrations as low as 0.29% have been found. 

INTURGEO (1988) The international uranium geology information system a world atlas of uranium occurrences and deposits. Technical Report lAEA-TECDOC-471, IAEA, Vienna... 

Mathews G. W. et al. Preliminary recognition criteria for uranium occurrences a field guide. Open File Rep. U.S. Dep. Energy GJBX-32(79), Feh. 1979, 47 p. 

Archaean supracrustal rocks are lacking in uranium occurrences, except for minor occurrences associated with late Archaean granitic rocks. Their absence within Archaean supracrustal rocks may appear enigmatic in view of the reducing nature of the Archaean atmosphere-hydrosphere and the many... 

The isotope, which constitutes only 0.71<% of any uranium occurrence, fissions naturally and is the principal fuel in conventional burner reactors (power plants). The isotope, which constitutes the bulk (99.3<7o) of any uranium occurrence, can be transformed into a useful fuel, the Pu... 

One of the major categories of uranium occurrences is that of sedimentary deposits. Such deposits are considered secondary occurrences in that they owe their existence to exogenic processes, but in these types the uranium was deposited at the same... 

Contact-metasomatic uranium occurrences form by replace-... 

The Bokan Mountain uranium occurrence is associated with the late Cretaceous to early Tertiary Bokan Mountain granite pluton on Prince of Wales Island in southernmost Alaska. The granite is an epizonal, circular ring-dyke complex intruded into eugeosynclinal metasediments and a Devonian( ) plutonic sequence.Its epizonal nature is shown by contact effects, roof pendants and associated hypabyssal intrusives. The lack of internal structures, discordance with structures in the metasediments and extensive alkali metasomatism suggest that it is a postorogenic intrusive. 

Cohenour R. E. Geology and uranium occurrences near Lakeview, Oregon. Rep. U.S. atom. Energy Comm. RME-2070, 1960, 33 p. 

Cunningham C. G. and StevenT. A. Postulated model of uranium occurrence in the central mining area, Marysvale district, west-central Utah. Open-File Rep. U.S. geol Surv. 78-1093, 1978, 20 p. 

The Caledonian province contains no known economic deposit, but some granite-related and sandstone-bound uranium occurrences occur in Scotland and Ireland, and there is some promise for these. 

The Hercynian region is by far the major economic uranium province. From the Iberian Meseta in the west to Lysa Gora to the east, with the exception of the Ardennes and the Harz Mountains, practically all the Hercynian outcropping massifs reveal uranium occurrences. The two major uranium districts (Western Massif Central, Vendee district, and the Western Bohemian Massif district), as well as all other significant uranium districts, however, occur within the Moldanubian zone, which corresponds to the inner unit of the Hercynian orogen or to the immediately adjacent outer zone. 

A remarkable feature of European uranium geology is that, wherever continental or epicontinental Permian cover rocks are found, they contain uranium occurrences often of economic value. Apart from Italy, many other areas can be mentioned. Well known is the Yugoslav deposit of Georenja Vas-Zirovski Vrh in northern Slovenia. 

Ertle H. J. Kneuper G. and Muller H. Sedimentary uranium occurrences in the Upper Carboniferous of the northern Black Forest. In Recognition and evaluation of uraniferous provinces (Vienna IAEA, 1977), 217-27. 

Lindroos H. and Smellie J. A stratabound uranium occurrence within middle Precambrian ignimbrites at Duobblon, northern Sweden. Econ. Geol., 74, 1979, 1118-30. 

From the outset exploration activity has been focused on the crystalline and continental volcanosedimentary formations of the Alps, Sardinia and Calabria and the alkaline Quaternary volcanics of central Italy. Uranium occurrences have been found in all these geological settings (Fig. 1), numerous mineralized showings and the Novazza and Val Vedello deposits occurring in the volcanosedimentary formations of the post-Hercynian basins of the Alpine range. 

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