Lateritic bauxite are the products of intense subareal weathering of rocks. It is characterised by a particular enrichment of aluminium-hydroxide minerals such as gibbsite, boehmite and diaspore. Based on geological occurrences, bauxite is classified as lateritic, karstic, tikhvin type and about 86% deposits of the world are lateritic bauxite deposits. They typically are in stable areas of plateaux, where they had sufficient geological time to form and were protected from erosion. India is endowed about 3896 million tons of bauxite resources and Maharashtra state constitutes about 5 % of the total assets. The medium to high grade lateritic bauxite occurrences are located in western Maharashtra which spread up in two distinct belts, viz. high level and low-level coastal areas. The coastal bauxite deposits in Raigad, Ratnagiri and Sindhudurg districts are located at altitude varying between 50 to 350 m above mean sea level (msl), while high level bauxite deposits of Kolhapur, Satara and Sangli districts occur on the plateaus with an elevation 900 to 1300 m above msl. Most of the laterite of the western Maharashtra overlies the Deccan Trap basalt, except in some part of coastal areas, it either caps the Kaladgi sandstone or overlie the Dharwar pebble beds. The lateritic bauxite deposits of the western Maharashtra have been studied with reference to its geology, chemico-mineralogy and petrological characteristics. Field studies indicate the following successive stages developed during in-situ weathering: Deccan trap basalt (parent rock) → weathered basalt → saprolite/lithomargic clay → bauxite → duricrust (ferruginous, aluminous laterites). The geological, physical and chemico-mineralogical characteristics of the bauxite and laterite located in two belts is distinguished from one another. For the present study, two bauxite deposits namely Ringewadi and Velas located in Kolhapur (high-level) and Raigad (coastal) district of western Maharashtra respectively have been selected. The representative samples of bauxite, laterite, saprolite, parent rock have been collected. In present paper, comparative study has been done and the geological, geomorphological, geochemical, mineralogical, petrographic and physical characteristics of low level (coastal) and high-level lateritic bauxite deposits are highlighted.

中文翻译：

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德干圈闭玄武岩上形成的红土铝土矿床地球化学、矿物学和岩石学特征参照马哈拉施特拉邦高位和沿海（低位）矿床

红土铝土矿是岩石局部区域强烈风化的产物。它的特点是特别富集氢氧化铝矿物，如三水铝石、勃姆石和水铝石。根据地质产状，铝土矿分为红土型、岩溶型、季赫温型，世界上约86%的矿床为红土型铝土矿矿床。它们通常位于高原的稳定区域，在那里它们有足够的地质时间形成并免受侵蚀。印度拥有约38.96亿吨铝土矿资源，马哈拉施特拉邦约占总资产的5%。中高品位红土铝土矿产地位于马哈拉施特拉邦西部，分布在两个不同的带中，即。高海拔和低海拔沿海地区。莱加德的沿海铝土矿矿床，Ratnagiri 和 Sindhudurg 区位于平均海平面 (msl) 以上 50 至 350 m 的高度，而 Kolhapur、Satara 和 Sangli 区的高水平铝土矿矿床出现在海拔 900 至 1300 m 的高原上。马哈拉施特拉邦西部的大部分红土覆盖在德干圈闭玄武岩上，除了沿海地区的某些部分外，它要么覆盖在 Kaladgi 砂岩上，要么覆盖在 Dharwar 卵石层上。已参考其地质、化学矿物学和岩石学特征对马哈拉施特拉邦西部的红土铝土矿矿床进行了研究。现场研究表明，在原位风化过程中形成了以下连续阶段：德干圈闭玄武岩（母岩）→风化玄武岩→腐泥土/岩质粘土→铝土矿→硬壳层（铁质、铝质红土）。地质学，位于两条带的铝土矿和红土矿的物理和化学矿物学特征相互区分。对于本研究，分别选择了位于马哈拉施特拉邦西部 Kolhapur（高位）和 Raigad（沿海）地区的 Ringewadi 和 Velas 两个铝土矿矿床。采集了铝土矿、红土、腐泥土、母岩的代表性样品。本文通过对比研究，重点介绍了低位（沿海）和高位红土铝土矿床的地质、地貌、地球化学、矿物学、岩相和物理特征。选择了分别位于马哈拉施特拉邦西部 Kolhapur（高位）和 Raigad（沿海）地区的 Ringewadi 和 Velas 两个铝土矿矿床。采集了铝土矿、红土、腐泥土、母岩的代表性样品。本文通过对比研究，重点介绍了低位（沿海）和高位红土铝土矿床的地质、地貌、地球化学、矿物学、岩相和物理特征。选择了分别位于马哈拉施特拉邦西部 Kolhapur（高位）和 Raigad（沿海）地区的 Ringewadi 和 Velas 两个铝土矿矿床。采集了铝土矿、红土、腐泥土、母岩的代表性样品。本文通过对比研究，重点介绍了低位（沿海）和高位红土铝土矿床的地质、地貌、地球化学、矿物学、岩相和物理特征。