【正文】 Some may be near laterite weathering products, handling by running water in to the limestone cave, so also known as karst type bauxite ore deposit distribution in Mediterranean countries and India, the former Soviet union and other 39。 Residual。這種鈾礦床的時空分布很廣，又可分為砂礫巖中的鈾礦床和煤或瀝青質(zhì)巖石中的鈾礦床兩類。中國南嶺地區(qū)有花崗巖風化殘余的重稀土元素礦床（釔族為主）。巖石中富鋁硅酸鹽礦物在潮濕溫暖氣候條件下風化 ,而形成 粘土礦物為主的堆積 ,根據(jù)原巖成分和風化程度而形成高嶺土礦床或膨潤土礦床。中國廣西平果鋁土礦是二疊系中的原生鋁土礦經(jīng)風化崩塌堆積而成。著名的西澳哈默斯利富鐵礦 ,礦石達 億噸，古巴卡臘賈斯鐵礦的天然合金鋼富礦 石也達到178 億噸，此外 ,在印尼、菲律賓、前蘇聯(lián)、美國也都有分布。因為殘積砂礦是物理風化產(chǎn)物，其成礦規(guī)律和礦床特點與其他成因的砂礦床（見 沉積礦床 ）類似，因而也可歸為砂礦床。規(guī)模大 的裂隙帶和破碎帶，決定了風化礦床的位置和延伸方向，同時也控制了風化礦床的深度。它對風化成礦作用有決定性影響。礦石疏松，便于開采加工。風化礦床中最多的是鐵礦和鋁土礦，其次是鎳、錳、鈾、銅、稀土元素、粘土、磷灰石、菱錳礦。高溫有利于原巖的分解和其中堿和堿土金屬的帶出，氣候潮濕雨量充沛也有利于風化作用，因此在熱帶亞熱帶地區(qū)最有利于風化礦床的形成。構(gòu)造運動還影響風化礦床的保存條件，在構(gòu)造上隆地區(qū)風化礦床易受剝蝕破壞，在沉降地區(qū)風化礦床則被掩埋，只有在微弱沉降的情況下，風化礦床才能被覆蓋而保存起來。 3 殘余礦床 地表巖石經(jīng)化學風化和生物風化作用后，一部分物質(zhì)被淋濾，而另一部分 殘留在風化殼中富集而成的礦床，也稱殘留礦床。這類礦床在中國不甚發(fā)育，但華北的山西式鐵礦，至少有一部分是含鐵碳酸鹽巖石風化產(chǎn)物。 ③紅土型鎳礦床。高嶺土以 高嶺石 為主要成分，是酸性和堿性硅酸鹽巖石風化過程中，尚未達到游離氧化鋁階段，形成了硅酸鹽礦物，而酸性介質(zhì)淋濾了鐵而形成的。華東的流紋斑巖中含輕稀土元素（鈰族）較多，在巖石風化時可富集成礦 。前者以美國科羅拉多高原的鈾釩礦床最著名，后者則是由于煤和瀝青是還原劑，促進了潛水中的鈾化合物沉淀富集而成礦的。 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 weathering, therefore the most favorable for the formation of weathering deposits in tropical and subtropical region. 5 (3) The terrain factors. Mountainous terrain elevation difference is big, weathering products is not easy to keep。s guangxi pingguo bauxite is primary bauxite by the weathering of the Permian collapsing. (3) Type laterite nickel ore called silicate mineral deposit, posed of ultrabasic rock in the tertiary, quaternary or living with tropical and subtropical serpentinite weathering the ultrabasic rock weathering, with such quality as mixed with nickel in olivine and pyroxene into the serpentine, serpentine again after the deposition, nickel analysis, namely into the solution, from top to bottom weathering crust, with secondary nickel minerals and enrichment of nickel minerals to settle and form 7 new caledonia in the south Pacific (French) silicate nickel deposit, 39。s central plateau has this type of ore type of bauxite deposit is