【正文】 one and along the contact surfaces of the two kinds of rock contact type by weathering profile and its forming mechanism can be divided into the top of the crust of weathering eluvial placer deposit, diving residual ore deposit and dive below the surface on the surface of the the eluvial placer is physical weathering products, and its characteristics and other metallogenic regularity and causes of the placer deposit (see sedimentary deposit), and therefore can be classified as placer deposit. 3 The residual deposit Surface after chemical weathering and biological weathering rock, part of the material was leached, and the other part of the residual accumulation in the weathering crust of deposits, also known as residual ore residual substance is stable under the condition of the 6 surface of the earth, including iron and aluminum is the most stable, after weathering as iron ore and bauxite in the upper crust of weathering mineralization and , phosphorus, manganese and cobalt, nickel, copper, uranium, vanadium is a bit poor stability, in other conditions favorable, can form oxides, phosphate and other stable oxygen salts as residual ore deposit. Has the following several important residual ore deposit (1) Red clay type iron ore rock in hot, humid area after a strong weathering leaching effect, magnesium and silicon are groundwater away from the rock, most low iron into high iron, high water cut of formation of refractory iron oxide, and then dehydration into results form the laterite weathering crust, the upper iron up to more than 50% to bee rich iron the ore body is the original rock residue rich in chromium, titanium, vanadium mineral or after weathering residues of cobalt, nickel, manganese ore, can direct smelting into high quality alloy western Australia hammer, rich iron ore, ore billion tons, Cuba card la just natural alloy rich ore of iron ore billion tons, in addition, in Indonesia, the Philippines, the former Soviet union, the United States also have development of this type of ore deposits in China, but in north China39。 Illuviation 1 Factors affecting weathering mineralization Basically has the following several aspects (1) The original rock position. Weathering of original rock is the source of oreforming materials. Basic and ultrabasic rock with high content of Fe, Ni, and easy to weathering, and beneficial to form the weathering of iron, nickel deposit. And like a feldspathic rock weathering can form various kinds of clay or bauxite deposit. (2) The weather conditions. It has a decisive effect on weathering mineralization. High temperature is beneficial to the deposition of the original rock and brought out one of the alkali and alkaline earth metal, damp climate rainfall amount and conducive to