Uranium and thorium in the Kupferschiefer formation, Lower Zechstein, Poland

NASA Astrophysics Data System (ADS)

Piestrzyński, A.

1990-05-01

The Kupferschiefer in Poland has an increased U content. The facies high in organic matter are significantly enriched in U. The maximum values of U are mostly in the lower part of the Kupferschiefer sequence. The mean (x) U content in the Kupferschiefer from the Lubin-Sieroszowice district is 61.5 ppm and from the rest of the Polish Zechstein basin is about 26 ppm. Thorium occurs only in small quantities (x) = 1.5 and 5 ppm respectively). The high variance of U and Th in the Kupferschiefer is due to multistage diagenetic processes. The main U carrier is thucholite. The investigated thucholite showed a Th-content below 0.36 ppm. Thucholite with uraninite exolutions showed small (up to 1.0 wt.%) admixtures of U and thucholite without microscopically visible exsolutions (up to 37.85 wt.% U). The phosphates showed significant amounts of U (up to 0.24 wt.). The U content in the Kupferschiefer is significantly lower than in black shales from other part of the world. Uranium in the Lubin district is not economic.

Selected annotated bibliography of the geology of uraniferous and radioactive native bituminous substances, exclusive of coals, in the United States

USGS Publications Warehouse

Jones, Harriet Nell

1956-01-01

Native bituminous substances are divided into two groups, 1) bitumens and, 2) pyrobitumens. Bitumens are composed principally of hydrocarbons substantially free from oxygenated bodies, are fusible, and are soluble in carbon disulfide. Native bitumens occur in liquid and solid forms. The native liquid bitumens include all petroleums or crude oils. Native solid bitumens include native waxes such as ozocerite, asphalts or petroleum tars, and asphaltites such as gilsonite and grahamite. Pyrobitumens are composed principally of hydrocarbons which may contain oxygenated bodies. They are infusible and are insoluble, or nearly insoluble, in carbon disulfide. Native pyrobitumens are divided into an oxygen-containing group including peats, lignites, and coals, and an essentially oxygen-free, asphaltic group including such substances as wurtzilite, albertite, impsonite, and ingramite. Thucholites, which are carbonaceous substances that may contain uranium, thorium, and rare earths, commonly are considered to be pyrobitumens. Their compositions are variable and may fall into either the oxygen-containing or oxygen-free group. All varieties of native bituminous substances may be associated with mineral matter. The nomenclature of bitumens and pyrobitumens is used very loosely in the literature. This circumstance arises from the difficulty in recognizing many of these substances by visual examination, and because many of them can be identified accurately only by chemical methods. Inasmuch as some of the chemical procedures are time-consuming and satisfactory analytical methods have not been devised for all these substances, geologists generally have not obtained precise identifications but rather have used names that appeared most appropriate to the circumstances. It is expected that future research will show many substances called "asphaltite," "thucholite," etc., to be incorrectly identified. The nomenclature used by the authors of the various references of this bibliography is followed without deviation or further discussion. The stratigraphic nomenclature also is that used by the authors. In this bibliography emphasis is placed on reports dealing with the uranium contents and radioactivity of native bituminous substances rather than on mineralogical and chemical studies of these substances. The distribution of the substances described in the references is shown on the accompanying map. The indicated presence of these substances does not infer that they contain sufficient radioactive elements to constitute ores.

Two-brine model of the genesis of strata-bound Zechstein deposits (Kupferschiefer type), Poland

NASA Astrophysics Data System (ADS)

Kucha, H.; Pawlikowski, M.

1986-01-01

These Kupferschiefer deposits were probably formed as a result of a mixing of two brines. The upper cold brine (UCB) is an unmineralized brine rich in Na, Ca, Cl and SO4, with a pH>7 and originating from evaporites overlying the metal-bearing Zechstein rocks. The lower hot brine (LHB) rich in Mg, K, Cl, SO4 and CO3 with a pH<=7 formed in sediments in the central part of the Zechstein basin at a depth of 7,000 m. This brine was subjected to heating and upward convection toward the Fore-Sudetic monocline along the bottom of the Z1 carbonates. During its migration, it caused albitization, serpentinization and leaching of the primary metal deposits in rocks underlying the Zechstein becoming enriched in heavy metals. The mineralization process, being a result of the mixing of the two brines (UCB and LHB), and catalytic oxidation of the organic matter of the black shale were initiated at shallow depths in the area of the Fore-Sudetic monocline. The boundary of the two brines generally overlapped the strike of the black shale. Parts of the deposit with shale-free host rock suggest that the action of two brines alone was capable of producing economic concentrations of Cu, Pb and Zn. Where the boundary of the two brines overlaps the autooxidation zone (the black shale bottom) and also coincides with γ radiation of thucholite, concentrations of noble metals result. The characteristic vertical distribution of the triplet Cu→Pb→Zn from the bottom upward is universal in the Kupferschiefer environment.