Abstract:

Heavy minerals prospecting is low cost but workable. Lots of clues and deposits (occurrences) were found through Tibet’s 1：200k heavy minerals survey, such as chromium, tungsten, tin, lead, zinc and molybdenum. Tibet’s chromites are chiefly hosted in the ultrabasic units of two ophiolite melange zones, one in south and one in north, in which heavy minerals anomalies are zoning, highly consistent with ultrabasic rocks and chromite deposits. The ultrabasic rocks contain large quantity of black chrome spinel, resistant to weathering, heavy, and stable, which is zoning as an outstanding prospecting. This paper discusses the prospecting direction in the two zones attempting to find new ultrabasic units or chromite resources.

Key words: ophiolite mélange, chromite, heavy minerals anomaly, Tibet

摘要：

重砂找矿法是一种成本低、效果明显的找矿方法。在西藏1:20万重砂测量中，发现了许多找矿线索及矿（床）点，取得了较好的找矿效果，特别是对铬、钨、锡、铅锌、钼等金属矿产效果极佳。西藏铬铁矿主要产出于南北两个蛇绿混杂岩带的超基性岩中，其自然重砂异常主要成群分布于两个蛇绿岩混杂岩带中，与超基性岩及铬铁矿点分布高度一致。西藏地区含铬铁矿的超基性岩中含有大量的抗风化强、比重大的黑色铬尖晶石等矿物，为稳定的自然重砂矿物，呈带状分布，是一种重要的找矿标志。拟以此作为找矿线索或找矿标志，拓展西藏铬铁矿南带和北带的找矿思路和找矿方向，以期待发现新的超基性岩或铬铁矿资源。

关键词: 蛇绿混杂岩, 铬铁矿, 重砂异常, 西藏