摘要
最近几年不仅在东秦岭地区又发现和探明一批大型—超大型斑岩型钼矿床,而且在南泥湖矿田(包括南泥湖-三道庄-上房沟矿床)和东沟超大型斑岩钼矿床外围探明了一批脉状铅锌银矿。这些脉状铅锌银矿与斑岩钼矿具有明显的时空关系,而且互为找矿指示。以南泥湖和东沟为代表的斑岩钼矿分别形成于晚侏罗世—早白垩世(156～137Ma)和白垩纪中期(125～114Ma),其成矿有关岩体指示成矿物质分别来源于壳幔同熔和壳源。尽管有物质来源的差别,但是在2个不同时代斑岩钼矿的外围都有一系列脉状铅锌矿的发育,而且通常在断裂膨大或拐弯处和2组断裂的交会部位形成大矿和富矿,也见出现在地层不整合界面的部位。这种钼与铅锌矿的密切时空分布关系构成一个很好的成矿系统,斑岩-矽卡岩钼矿与铅锌银矿互为找矿的指示标志。矿床模型的建立有利于进一步推动在中国东部地区开展此类矿床组合的找矿勘查。
A decade of molybdenum deposits comprising several large-supper large ones have been explored in the past several years. At the same time a lot of vein-type Pb-Zn-Ag deposits are discovered, which are distributed around the porphyry molybdenum deposits, such as the Nannihu giant porphyry molybdenum ore district and the Donggou giant porphyry molybdenum deposit, a new property. These vein-type Pb-Zn-Ag deposits obviously exhibit a close relationship to the porphyry Mo deposits in space and time, sharing one ore system. The porphyry molybdenum deposits in the episodes of 156-137Ma and 125-114Ma represented by the Nan- nihu and the Donggou, are derived from anatexis of the mantle and crust, and the crust only, respectively. Although the two episodes of mineralization have differences of the ore-forming time and sources the mineralization zoning reflects a normal temperature-decreasing process around the high-fractionation granite plutons associated with the all porphyry deposits. On the other hand, the granite plutons are able to act as energy engines, which triggered to form the convective hydrothermal system. The hydrothermal solution in the system leached the ore-substances from the host rocks of carbonate and discharged them in the available structures, for instance, the extension locations of faults, and discordant boundary of the strata. In light of the basic characteristics of the ore system and understanding for the metallogenic process, we propose a new model to describe.
出处
《地质通报》
CAS
CSCD
北大核心
2009年第1期72-79,共8页
Geological Bulletin of China
基金
中国地质调查局国土资源大调查项目(编号:1212010634001)
国家自然科学基金项目(批准号:40434011)资助成果
关键词
矿床模型
斑岩钼矿
脉状铅锌银矿
中生代
东秦岭地区
mineral model
porphyry molybdenium deposit
vein-type Pb-Zn-Ag deposit
Mesozoic
eastern Qinling
