Rocks and

To assess potential yield and maturity of source rocks and classify those according to their vitrinite reflectance . 

The formation density log is the main tool for measuring porosity. It measures the bulk density of a small volume of formation in front of the logging tool, which is a mixture of minerals and fluids. Providing the rock matrix and fluid densities are known the relative proportion of rock and fluid (and hence porosity) can be determined. 

Nearly all reservoirs are water bearing prior to hydrocarbon charge. As hydrocarbons migrate into a trap they displace the water from the reservoir, but not completely. Water remains trapped in small pore throats and pore spaces. In 1942 Arch/ e developed an equation describing the relationship between the electrical conductivity of reservoir rock and the properties of its pore system and pore fluids. 

After oxygen, silicon is the most abundant element in the earth s crust, It occurs extensively as the oxide, silica, in various forms, for example, flint, quartz, sand, and as silicates in rocks and clays, but not as the free element, silicon. Silicon is prepared by reduction of silica, Si02- Powdered amorphous silicon can be obtained by heating dry powdered silica with either powdered magnesium or a... 

It does not occur free in nature combined it is found in small units in nearly all igneous rocks and in the waters of many mineral springs. Lepidolite, spodumeme, petalite, and amblygonite are the more important minerals containing it. 

Vanadium is found in about 65 different minerals among which are carnotite, roscoelite, vanadinite, and patronite, important sources of the metal. Vanadium is also found in phosphate rock and certain iron ores, and is present in some crude oils in the form of organic complexes. It is also found in small percentages in meteorites. 

Titanium oxide bands are prominent in the spectra of M-type stars. The element is the ninth most abundant in the crust of the earth. Titanium is almost always present in igneous rocks and in the sediments derived from them. 

Petroleum—a natural mineral oil—was referred to as early as the Old Testament. The word petroleum means rock oil [from the Greek petros (rock) and elaion (oil)]. It has been found for centuries seeping out of the ground, for example, in the Los Angeles basin in what are now called the La Brea tar pits. Vast deposits were found in Europe, Asia, the Americas, and Africa. 

The previous discussion has centered on how to obtain as much molecular mass and chemical structure information as possible from a given sample. However, there are many uses of mass spectrometry where precise isotope ratios are needed and total molecular mass information is unimportant. For accurate measurement of isotope ratio, the sample can be vaporized and then directed into a plasma torch. The sample can be a gas or a solution that is vaporized to form an aerosol, or it can be a solid that is vaporized to an aerosol by laser ablation. Whatever method is used to vaporize the sample, it is then swept into the flame of a plasma torch. Operating at temperatures of about 5000 K and containing large numbers of gas ions and electrons, the plasma completely fragments all substances into ionized atoms within a few milliseconds. The ionized atoms are then passed into a mass analyzer for measurement of their atomic mass and abundance of isotopes. Even intractable substances such as glass, ceramics, rock, and bone can be examined directly by this technique. 

These effects of differential vapor pressures on isotope ratios are important for gases and liquids at near-ambient temperatures. As temperature rises, the differences for volatile materials become less and less. However, diffusion processes are also important, and these increase in importance as temperature rises, particularly in rocks and similar natural materials. Minerals can exchange oxygen with the atmosphere, or rocks can affect each other by diffusion of ions from one type into another and vice versa. Such changes can be used to interpret the temperatures to which rocks have been subjected during or after their formation. 

Spherulites have been observed in organic and inorganic systems of synthetic, biological, and geological origin, including moon rocks, and are therefore not unique to polymers. 

Uranium is present in small (50—200 ppm) amounts in phosphate rock and it can be economically feasible to separate the uranium as a by-product from the cmde black acid (30% phosphoric acid) obtained from the leaching of phosphate for fertilizers (qv). The development and design of processes to produce 500 t U Og per year at Ereeport, Louisiana have been detailed (272). 

Direct Application Rock. Finely ground phosphate rock has had limited use as a direct-appHcation fertilizer for many years. There have been widely varying results. Direct appHcation of phosphate rock worldwide amounts to about 8% of total fertilizer phosphate used, primarily in the former Soviet Union, France, Brazil, Sri Lanka, Malaysia, and Indonesia. The agronomic effectiveness of an apatitic rock depends not only on the fineness of the grind but also strongly on the innate reactivity of the rock and the acidity of the sod performance is better on more acid sods. Probably more than half of the potentially productive tropical sods are acidic, some with pH as low as 3.5—4.5. Certain phosphate rocks may thus become increasingly important as fertilizer in those areas. The International Fertilizer Development Center at Muscle Shoals, Alabama is active in researching this field (30). 

NSP is produced by the reaction of phosphate rock and sulfuric acid. This reaction quickly yields a soHd mass containing monocalcium phosphate monohydrate and gypsum, CaSO 2H20, according to the simplified equation... 

Cost Fa.ctors, The dehvered costs of the phosphate rock and sulfuric acid raw materials often account for more than 90% of the cost of producing NSP, thus the production cost varies considerably with plant location. Because the rock is richer in P2O5 than is the low analysis NSP product, NSP need not be produced near the phosphate mine. However, deUvery of sulfuric acid and shipment of product to market are important cost factors. Most United States NSP plants have been located east of the Mississippi river, with concentration in the southeastern and extreme southern parts of the country where the largest use of the product has occurred. Production and use of the product also has been high in California. 

Triple (Concentrated) Superphosphate. The first important use of phosphoric acid in fertilizer processing was in the production of triple superphosphate (TSP), sometimes called concentrated superphosphate. Basically, the production process for this material is the same as that for normal superphosphate, except that the reactants are phosphate rock and phosphoric acid instead of phosphate rock and sulfuric acid. The phosphoric acid, like sulfuric acid, solubilizes the rock and, in addition, contributes its own content of soluble phosphoms. The result is triple superphosphate of 45—47% P2 s content as compared to 16—20% P2 5 normal superphosphate. Although triple superphosphate has been known almost as long as normal superphosphate, it did not reach commercial importance until the late 1940s, when commercial supply of acid became available. 

Calcium. Calcium is the fifth most abundant element in the earth s cmst. There is no foreseeable lack of this resource as it is virtually unlimited. Primary sources of calcium are lime materials and gypsum, generally classified as soil amendments (see Calcium compounds). Among the more important calcium amendments are blast furnace slag, calcitic limestone, gypsum, hydrated lime, and precipitated lime. Fertilizers that carry calcium are calcium cyanamide, calcium nitrate, phosphate rock, and superphosphates. In addition, there are several organic carriers of calcium. Calcium is widely distributed in nature as calcium carbonate, chalk, marble, gypsum, fluorspar, phosphate rock, and other rocks and minerals. 

E. Eeldman and co-workers, ia G. Rock and M. J. Segatchian, QualityMssurance in Transfusion Medicine, Vol. II, CRC Press, Boca Raton, Ela.,... 

Ore. The assay of mercury ores is not simple, owing to the difficulties encountered in obtaining representative ore samples. Crystalline cinnabar is extremely brittie causing it to break loose from adjacent rock and fall into the sample being collected. This uncontrollable salting of the sample can give results as much as several hundred percent over the actual mercury content of the sample. 

Geochemical Nature and Types of Deposits. The cmst of the earth contains approximately 2—3 ppm uranium. AlkaHc igneous rock tends to be more uraniferous than basic and ferromagnesian igneous rocks (10). Elemental uranium oxidizes readily. The solubiHty and distribution of uranium in rocks and ore deposits depend primarily on valence state. The hexavalent uranium ion is highly soluble, the tetravalent ion relatively insoluble. Uraninite, the most common mineral in uranium deposits, contains the tetravalent ion (II). 

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