福建省连城锰矿四号矿点锰矿床成因探讨

THE GENESIS OF NO.4 MANGANESE ORE DEPOSIT IN THE LIANCHENG MANGANESE MINE, FUJIAN PROVINCE

本文从区域地质、矿床地质特征和矿床的碳、氧、硫同位素组成三方面,论述连城锰矿四号矿点锰矿床的成因,认为矿床赋存于断层带倒转向斜内,系沉积变质而成。

The Liancheng Manganese Mine is located in the Yongmei depression, which is represented by the Miaoqian synclinorium made up of Upper paleozoic strata. The Chuanshan Formation is rich in manganese and can be correlated regionally with the lithofacies and fusulinida zone. No. 4 Manganese Ore Deposit occurs in a small close overturned syncline in a fault zone in the southern part of the Miaoqian Mine area. Orebodies consist of primary manganese ore and its supergene oxidized manganese ore. The country rocks are limestone of the Chuanshan Formation, clastic rocks of the Lindi Formation and late Yanshanian granite porphyry The ore deposit is of sedimentary-metamorphic orgin. The horizon of occurence is the upper member of the Chuanshan Formation. The main grounds are as follows: (1)The ore deposit contains manganese carbnate ore which exhibits lime-mud granular texture (an indicationof marine sediments) and rich in microfossils such as fusulinds and algae; the ore bed s occur in the same biostratigraphical interval that is, the Pseudoschwagerina zone and are stratigraphically persistent. (2) Metamorphic ore minerals, Chemical composition, textures and structures, and carbon and oxygen isotopic composition show that the ore deposit has an affinity with marine ere deposits. The ore deposit is of high-manganese,low-phosphorus and-iron type. It contains many kinds of metals such as silver and lead, so is of high economic value. The determination of the horizon of occurrence of the manganese ore deposit has revealed a main manganese-bearing horizon in this area. It is of theoretical significance in finding primary manganese ore deposits and secondary oxidized manganes ore deposits in this area and southwesteren Fujian province