Secondary deposits

U and Th concentrations in secondary deposits precipitated from solution generally reflect relative abundances in the hydrosphere. Uranium is co-precipitated with CaCOs in subaerial environments on exsolution of CO2 (or evaporation), while the immediate daughter products are essentially absent. This represents extreme chemical fractionation of parent and daughter isotopes within the hydrosphere. 

Certain proteases may have additional actions that enhance invasion and metastasis. For example, both uPA (K7, K8) and CD (VI) are mitogenic in vitro. However, whether these proteases are physiological mitogens remains to be shown. If either uPA or CD enhances cell division in vivo, this in turn might indirectly increase the probability of invasion and metastasis. Also, autocrine production of mitogens might be important at sites of implantation in order to stimulate growth of secondary deposits. 

Occurrence. In order of abundance in the earth s crustal rocks, it is the third within the transition elements (after Fe and Ti) and the 12th in the general order of all the elements. It occurs in several minerals such as primary deposits of silicates and as secondary deposits (commercially more important) of oxides and carbonates as pyrolusite, Mn02, hausmannite, Mn304, rhodochrosite, MnC03, etc. Large amounts of manganese are present in the deep sea nodules located over certain areas of the ocean floor. 

Humic acids and fulvic acids interact with a wide variety of cations. In addition to interacting with iron and aluminium, the species with which they are complexed in soils (57), they also form stable complexes with zirconium, thorium, the lanthanides and the uranyl ion. In the case of uranium it has been suggested that humic acids could be of considerable importance in the geological formation of secondary deposits of uranium (58). 

The rounded forms of natural diamond crystals are commonly observed in crystals occurring both in alluvial deposits (secondary deposits) and in mother rocks... 

Dr. Gluskoter. What is the evidence for a syngenetic origin for the uranium minerals in the Swiss anthracite Why could this not be secondary deposition along planes of weakness (bedding) ... 

AMYGDALOID. A vesicular rock, commonly lava, whose cavities have become filled with a secondary deposit of mineral material such as quartz, calrite, and zeolites. The term is derived from the Creek v. ord meaning almond in reference to the frequent almondlike appearance of flic filled vesicles, which are called amygdales or amygdules... 

Secondary deposition from either percolating solutions or gaseous emanations front intrusive formations, causing chemical reactions within the intruded formations. 

These metals occur in both primary and secondary deposits. The primary deposits are generally associated with Ni-Cu sulfide ores. The Sudbury ores of Canada and the deposits of the Bushveld complex of South Africa are of this type. Native platinum occurs as a primary deposit in the Ural Mountains of the former U.S.S.R. and also in the Choco district of Colombia. Weathering and erosion of these deposits have resulted in the formation of secondary, or placer, deposits of native Pt in riverbeds and streams. One nugget of Pt found in Ihe Urals weighed over 25 pounds (11.3 kilograms). Most of the world s platinum comes from Canada, the former... 

Geological samples were collected from primary sources and secondary deposits of obsidian. In most cases, the geographic coordinates of source samples were also recorded. The geological samples were shipped to MURR for sample preparation and analysis. 

Katharina Schreiber located a primary deposit of obsidian known as Jampatilla in 1981, during a survey in nearby Huaycahuacho. Huaycahuacho is located in the Carhuarazo Valley and Province of Lucanas, Department of Ayacucho. The obsidian deposit was discovered 3-4 km east-northeast of the town of Huaycahuacho and 55 km north of the larger town of Puquio. Obsidian workshop areas and associated archaeological sites were reported (57). Nodules ranging up to 10-12 cm in diameter were found at the source, but smaller eroded samples were more common in secondary deposits. 

Tin-mining methods depend on the character of the deposit. Primary deposits are embedded in undeiground granitic rock and recovery methods are complex. The more important secondary deposits are in the form of an alluvial mud in the stream beds and placers and the recovery is simpler than lode mining. Cassiterite is recovered from alluvial deposits by dredging, hydraulicking where a head of water permits it, jets and gravel pumps on level... 

Occurrence.—The greater part of the world s gold is found in the metallic state either in primary deposits in veins in association with quartz, or as alluvial gold in secondary deposits in the form of dust, grains, fine leaves, or in larger pieces. 

Petrographic comparison of the Mexico City majolica with Teotihuacan sherds shows that except for the secondary deposition of carbonates, which is present in the majolica but absent in the Precolumbian sherds, the mineral composition of both sets of specimens is very similar. Both notably include hornblende and similar feldspars as inclusions, and both are low in quartz. Similarly, except for the calcite in the majolica, both sets of sherds show similar x-ray diflFraction patterns. The mineralogical evidence, therefore, strongly suggests that both sets of sherds were made from closely related clays and that the compositional diflEerences that exist between them are primarly the result of the accumulation of a secondary calcareous deposit within the majolica sherds during burial in the wet soil of Mexico City. 

We have been able to compare our samples to a small group of majolica sherds from Spain and to a reasonably large group of Precolumbian sherds from Teotihuacan. The majolica sherds from Caribbean sites agree in composition with the Spanish specimens, and those from sites in Mexico City have compositions sufBciently similar to the sherds from Teotihuacan, considering the secondary deposits of carbonates of calcium which are in the majolica sherds and not in the Precolumbian sherds. The presence of these deposits of carbonates of calcium in the majolica and their absence in the Precolumbian sherds was determined by petrographic examination and x-ray diflFraction as well as by elemental analysis. 

Luminous chemical vapor deposition (LCVD) and luminous gas treatment (LGT), which does not yield the primary deposition, could be used in the preparation and modification of membrane and barrier [1]. The term primary deposition refers to the direct deposition of material from the luminous gas (LCVD) in contrast to secondary deposition that results from the deposition of ablated material in LGT. It should be emphasized, however, that both methods are nanofilm technologies and require the substrate membrane on which LCVD nanofilm is deposited or the surface is modified. Accordingly, their use should be limited to special cases where such a nanofilm could be incorporated into membrane or the LGT of surface is warranted. 

Baltic amber is found as secondary deposits in much of Denmark and southern Sweden, in layers laid down 30 000 years ago. It is not mined but turns up when foundations are laid for bridges or buildings. 

Caves act as repositories for secondary deposits of many kinds, some locally derived such as breakdown from collapse of cavern roofs, some transported such as sand and silt carried by underground streams, and some the result of chemical deposition in the cavern void space such as calcite and gypsum speleothems. Textbooks on karst hydrology commonly provide descriptions and overall classifications of cave sediments (e.g. Bogli,... 

Raw kaolin is mainly extracted by open cast mining. Secondary deposits can be exploited using excavators, whereas primary deposits of kaolin are often washed out of the rock with a high pressure water jet. 

Ilmenite (Fe,Mg,Mn)Ti03 occurs naturally in primary and secondary deposits. The Ti02-content is 43 to 61 % and the iron oxide content 34 to 39%. The impurities are mainly Mn, Mg, Al, Si, Cr, V, Nb and Sb. Primary deposits of ilmenite are found in Norway, Russia, Finland, Canada and the USA. However, secondary deposits are more important raw materials due to their easier processing (sands). They are found in South Africa, Australia, India, Brazil, Malaysia and Egypt. 

Dilute. sulfuric acid is generally u.sed as the acidic leaching agent. This digests the uranium(VI) oxide, which mainly occurs in secondary deposits, to uranyl sulfate ... 

UO3 from secondary deposits is digested to uranyl sulfate... 

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