Sandstone sources

Kolker, A., Cannon, W. E., Westjohn, D. B., and Woodruff, L. G., 1998a, Arsenic-rich pyrite in the Mississippian Marshall Sandstone Source of anomalous arsenic in southeastern Michigan ground water in Geological Society of America Annual Meeting, Toronto, Ontario, p. A-58. 

The camotite and roscoeHte ores in the sandstones of the Colorado Plateau have been important sources of vanadium as well as of uranium. 

Barite [13462-86-7], natural barium sulfate, BaSO, commonly known as barytes, and sometimes as heavy spar, tiU, or cawk, occurs in many geological environments in sedimentary, igneous, and metamorphic rocks. Commercial deposits are of three types vein and cavity filling deposits residual deposits and bedded deposits. Most commercial sources are replacement deposits in limestone, dolomitic sandstone, and shales, or residual deposits caused by differential weathering that result in lumps of barite enclosed in clay. Barite is widely distributed and has minable deposits in many countries. 

Most natural waters contain more hardness than bicarbonate. Only a few sources in the UK, usually from wells in sandstone strata, contain more alkalinity than hardness. In most cases the temporary hardness greatly exceeds the permanent hardness. This is especially tme of the hard alkaline waters, which come from chalk and limestone measures. 

By far the most important ores of iron come from Precambrian banded iron formations (BIF), which are essentially chemical sediments of alternating siliceous and iron-rich bands. The most notable occurrences are those at Hamersley in Australia, Lake Superior in USA and Canada, Transvaal in South Africa, and Bihar and Karnataka in India. The important manganese deposits of the world are associated with sedimentary deposits the manganese nodules on the ocean floor are also chemically precipitated from solutions. Phosphorites, the main source of phosphates, are special types of sedimentary deposits formed under marine conditions. Bedded iron sulfide deposits are formed by sulfate reducing bacteria in sedimentary environments. Similarly uranium-vanadium in sandstone-type uranium deposits and stratiform lead and zinc concentrations associated with carbonate rocks owe their origin to syngenetic chemical precipitation. 

Oils The n-alkane series Cg-C, toluene and cyclohexane were purchased from BDH, Poole, UK, each with a stated purity of 99% reagents were used as received. Crude oil samples were obtained from two North Sea fields one located in the Norwegian sector and the other from the UK sector. Stock tank oil from the Gullfaks field was supplied by Statoil, Norway and the other stock tank oil from an undisclosed source. Both crude oils are derived from sandstone formations with reservoir temperatures of 70° and 101°C respectively. 

Considerable geographic variability exists in the distribution of the source rocks contributing salts to river and groundwaters. As shown in Table 21.3, most of the evaporites, which are the dominant natural source of Na and Cl in river water, lie in marginal and endorheic (internal) seas. Some of these subsurfece evaporite deposits dissolve into groundwaters, which eventually carry Na and Cl into the ocean. Carbonates are the prevalent rock type between 15°N and 65°N. Precambrian-age crustal rocks and meta-morphic minerals predominate between 25°S and 15°N and north of 55°N. Shales and sandstones represent on average 16% of the terrestrial surfece lithology. 

There is no doubt of the presence of roll fronts in the Horton Group sandstones, however the source of the uranium within the system may be related to the weathered horizons beneath the Horton Group rocks and not exclusively the result of diagenetic change within the sandstones (Ryan O Beirne-Ryan 2007). 

CARNOTITE, This mineral is a vanadate of potassium and uranium with small amounts of radium. Its formula may be written K (UCL) (VOah JHsO. The amount of water, however, seems to be variable. It occurs as a lemon-yellow earthy powder disseminated through cross-bedded sandstones with rich concentrations around petrified and carbonized trees. Soft sp gr 4.7. It was mined in Colorado and Utah as a source of radium. Other localities are in Arizona. Pennsylvania, and Zaire. 

Sedimentary strata typically consist of mixtures of clay, silt, sand, organic matter, and various minerals formed by or from deposits of sediments, especially from sand grains or silts transported from their source and deposited in water, such as sandstone and shale or from calcareous remains of organisms, such as limestone. 

Source/Characteristic Interbed sandstone Interbed sandstone/ claystone Interbed tuff... 

The uranium that is found in roll-front deposits is generally believed to be derived from the dissolution and leaching of host minerals by soil water and ground water (2 3). Typical source rocks for the uranium are granites, tuffs, and tuffaceous sandstones that have relatively high concentrations of uranium in... 

That the atomic weight of uranium lead is extremely variable has already been shown. In order to interpret this variability its sources must be studied both geologically and mineralogically. On the geologic side of the question the uranium ore can be divided in to three principal classes, which are sharply distinct. The definitely crystallized varieties of uraninite occur in coarse pegmatites, associated with feldspar, quartz, mica, beryl, and other minor accessories. The massive pitchblende is found in metalliferous veins, together with sulphide ores of copper, lead, iron, zinc, and so forth. As for camotite, that is a secondary mineral, found commonly as an incrustation on sandstone, and often, also upon fossil wood. There may be other modes of occurrence, but these are the most distinctive. 

Deterioration of ancient stonework appears to have accelerated very markedly in many places in the present century Winkler [109], whose treatise on the durability of stone is the major source for the material in this section, shows photographs of early eighteenth century sandstone statues in places close to the Rhine—Ruhr industrial region. After two hundred years, at the beginning of the present century, these statues had clearly delineated features of faces, hands, etc. Sixty years later, they appeared rough outlines, faceless and handless. If this deterioration indeed owes nothing to the military activities of two world wars, it is a remarkable illustration of the effects of industrial pollution of the atmosphere. 

Environmental conditions related to rock surface exposure have profound effects on biofilm development, as metabolic activity and growth are directly connected to the availability of water, energy sources and nutrients, as well as to conditions of temperature and irradiation. Another important factor for establishment of subaerial biofilms is the resistance of the supporting substrate to environmentally and biologically influenced disintegration and dissolution (wear-down). Rapidly weathering rock surfaces (e.g. porous sandstone in an intertidal coastal zone) show little or... 

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