Sedimentary deposits

Zeolites are tire product of a hydrotliennal conversion process [28]. As such tliey can be found in sedimentary deposits especially in areas tliat show signs of fonner volcanic activity. There are about 40 naturally occurring zeolite types. Types such as chabazite, clinoptilolite, mordenite and phillipsite occur witli up to 80% phase purity in quite large... 

Sources. Iron ore deposits were formed by many different processes, eg, weathering, sedimentation, hydrothermal, and chemical. Iron ores occur in igneous, metamorphic, and sedimentary deposits. Normally, as-mined iron ore contains 25 to 68% iron. 

Clays and Other Sources. Sedimentary deposits, especially hthium-bearing clays found in the western United States, offer an additional source of lithium. These clays contain lithium-hearing trioctahedral smectites, of which hectorite [12173-47-6] NaQ23(Mg,Li)2Si402Q(F,0H)2, is one mineral. 

Mining of the ore deposit constitutes a significant cost, especially in hard rock mining. Mining costs vary considerably from ore to ore and from a few cents to well over 100/t mined. Underground mining is the most expensive hydrauHc mining of sedimentary deposits is the least expensive. 

The western phosphates are sedimentary deposits in adjoining areas of Wyoming, Idaho, and Utah derived from a former inland sea. They consist of layers of limestone, phosphate, and chert, now budded and faulted so they are rarely horizontal. The phosphate ore is strip-mined using large earth-moving equipment such as shovels, scrappers, dump tmcks, and bulldozers to mine the overburden and phosphate ore. Mining ratios of overburden to metric ton of recovered ore are from 1—3 m /1 (2—4 yd /short ton). The typical mining practice is to remove ore and overburden from a pit in discrete layers (Lifts) of 10—20 m in depth. Overburden from the pit is back-hauled to a previously mined pit. Extensive land reclamation practices are later carried out to return the mine areas to natural states. 

Petroleum, and the equivalent term cmde oil, cover a vast assortment of materials consisting of gaseous, Hquid, and soHd hydrocarbon-type chemical compounds that occur in sedimentary deposits throughout the world (3). When petroleum occurs in a reservoir that allows the cmde material to be recovered by pumping operations as a free-flowing dark- to light-colored Hquid, it is often referred to as conventional petroleum. 

Soil does not provide as solid a base as rock. The strength of a foundation built on soil and its ability to withstand an earthquake will therefore depend upon the quality and depth of soils which may be formed of a number of soil layers of different stratifications and depths. Sandy soil or soil with sedimentary deposits, for instance, will have less strength and will provide a weaker base, as such soils may settle more during a ground movement. 

Calcium, as noted above, is the fifth most abundant element in the earth s crust and hence the third most abundant metal after A1 and Fe. Vast sedimentary deposits of CaC03, which represent the fossilized remains of earlier marine life, occur over large parts of the earth s surface. The deposits are of two main... 

Sedimentary deposits are usually carried to the region of deposition by water and are deposited in water. (In some cases deposits are carried by wind or ice.) It is within these water leposited sediments that hydrocarbons are likely generated from the plant and animal life that exists in these environments. Two principal properties of the sedimentary rocks that form from such deposits are porosity and permeability. 

The foregoing theoretical overburden pressure gradient assumes that the sedimentary deposits together with the saline water are a mixture of materials and fluid. Such a mixture could be considered as a fluid with a new specific weight of... 

Any sedimentary deposit or foulant that fails to form a crystalline scale. Often the result of supersaturation or the binding of biological or other organic material with dust, sand, or other mineral deposits. Also, sludge is not always deposited at point of origin and can additionally bake onto heat transfer surfaces. 

The zoogeographic history of the Japan Sea proposed by Chinzei (1991) (Fig. 4.5 and Fig. 4.6) indicated that (1) from 17 to 15 Ma, before the spreading of the Japan Sea, tropical and subtropical molluscs invaded the area (2) the benthic and planktonic faunas changed sharply into low temperature faunas at about 15 Ma (3) from about 10 to 5 Ma, sedimentary deposits formed that were barren of benthic molluscs as a result of the stagnation of the Japan Sea basin (4) cold-water molluscan fauna reappeared in the coastal areas at about 5 Ma and (5) this has been followed by a period of marked cyclicity of cold and warm water faunas since about 1.3 Ma. 

U/ 32jj activity ratio of -0.8 (equivalent to a Th/U weight ratio of 3.8), and this is often taken to represent that of the host rocks in the absence of direct measurements, although this can of course be substantially different in rocks such as limestones or other sedimentary deposits. If it is assumed that the groundwater profile is in steady state, that weathering and precipitation are not important for these nuclides, and that the parent nuclides ojh and have similar behaviors, then the corresponding terms in... 

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. 

Volcano-sedimentary ore deposits are syngenetic deposits precipitated from sea water enriched in metals by submarine volcanic activity. Deposits of this type are also called submarine exhalative-sedimentary deposits. Stratabound lead-zinc-copper deposits associated with marine sedimentary volcanic sequences belong to this category. Important examples are Kuroko deposit in Japan, Mt. Isa in Australia, Sullivan deposit in British Columbia, Canada, Rammelsberg in Germany and Rampura-Agucha in Rajasthan, India. 

Reg soils are closely associated with desertic regions. They have developed on stable surfaces where coarse, gravelly desert alluvium is exposed, and are characterized by a well-developed desert pavement and exhibit some well-defined soil horizons. They occur mostly on depositional surfaces where stones and gravels have been deposited since Neogene times. The surfaces commonly consist of stony, unconsolidated sedimentary deposits in which limestone, dolomite, chalk, flint and marl predominate, together with some fines (silt and clay). Sandstone and granite debris have also been reported to contribute to Reg formation. Less frequently, they form on sedimentary bedrock (Fig. 1.5). 

Sedimentary deposits are the most important deposits of economic values. These deposits contain tantalocolumbite, columbite, samorskite and torolite. The Ta/Nb from these deposits is recovered using a gravity concentration method. 

Polkin, C.I., Concentration of Rare Earth Ores from Sedimentary Deposits, Obogaschenie Rud Retkih and Blagovodish Metalov (eds.), Izdatelstvo Nedra Moskva, pp. 268-275, 1987. 

The site is underlain by a sequence of unconsolidated, stratified sedimentary deposits. The water table occurs at depths of 52 to 71 ft below the ground surface, with occasional perched zones at depths of about 52 to 64 ft below the ground surface. Review of boring logs and well construction details and performance allowed for reevaluation of the subsurface environment. The soils were subsequently characterized based on relative permeability and depositional environment (Figures 12.21 and 12.22) as follows ... 

A better insight into the mechanisms of the individual steps in the formation of crystals would be of great help in explaining the creation and transformation of sedimentary deposits and biological precipitates. Valuable reviews are available on the principles of nucleation of crystals and the kinetics of precipitation and crystal growth (Zhang and Nancollas, 1990 Steefel and Van Cappellen, 1990 Van Cappellen, 1991). Only a few important considerations are summarized here to illustrate the wide scope of questions to be answered in order to predict rates and mechanisms of precipitation in natural systems. 

Measurements of radionuclides and metals in marine sediments and particulate matter are conducted for a variety of purposes, including the determination of sedimentation rates, trace metal and radionuclide fluxes through the water column, enrichment of metals in specific phases of the sediments, and examination of new sedimentary phases produced after sediment deposition. Such studies address fundamental questions concerning the chronology of deep-sea and near-shore sedimentary deposits, removal mechanisms and cycling of metals in the ocean, and diagenesis within deep-sea sediments. 

Clay (1) A grain whose diameter is less than 4 pm. Most are inorganic silicates. (2) A sedimentary deposit that is composed of more than 70 percent by mass clay-sized grains. 

Continental rise The large sedimentary deposit that lies at the foot of the continental slope. 

Mud A sedimentary deposit composed of 70 percent or more by mass silt and clay-sized grains also called deep-sea muds. 

Porosity A measure of the open space between grains in a sedimentary deposit. 

Turbidite The sedimentary deposit created by turbidity currents. The latter are underwater mudslides common to the continental slope and rise. 

Kaolin clays are naturally occuring sedimentary deposits composed largely of kaolinite mineral. Typical impurities in these deposits are iron oxides, titanifer-ous minerals, silica, feldspar, mica, sulfides and organic matter. The majority of kaolin clay produced in the world is used in the paper industry as coating and filler materials. This mineral also makes an excellent filler, carrier, opacifier and diluent in a variety of industrial products such as paints, plastics, cement, rubber, pharmaceuticals, etc. 

Phosphorus is one of the most widely distributed elements on earth. It is found as phosphate salts in nearly all igneous rocks and in sedimentary deposits and sea beds. Phosphorus occurs in more than three hundred minerals, usually associated with Ca, Mg, Fe, Sr, Al, Na, and several other metals, and with anions such as silicates, sulfates, oxides, hydroxides, and hahdes. 

---