南岭成矿带中、东段的第二找矿空间--来自同位素年代学的证据

The second ore-prospecting space in the eastern and central parts of the Nanling metallogenic belt:evidence from isotopic chronology

辉钼矿的Re-Os同位素年代学研究表明,南岭东段赣南地区的庵家滩钨矿床的成矿年龄为156Ma,园岭寨钼矿床的成矿年龄为160Ma。已有同位素年代学数据的统计显示,南岭成矿带的中、东段中生代的成矿作用可划分为3期7个阶段:即印支期的～225Ma左右和～195Ma左右,燕山早期的170～160Ma、160～150Ma和150～145Ma,燕山晚期的～135Ma和～100Ma。在3期成矿作用中,燕山早期的成矿作用最为强烈,也是南岭成矿带中、东段的钨锡矿床主要成矿期,矿床类型丰富多样,既有独立的钨锡多金属矿床,也有独立的锡矿床;既有铜、铅、锌多金属矿床,也有独立的钼矿床、金矿床等。同位素年代学及其新的找矿进展表明,从横向上,该区域可能存在的未被发现或重视的矿产种类;在纵向上,讨论了已知矿床深部的成矿潜力,为开展南岭中、东段地区的第二空间的地质找矿提供了理论证据。

A study of Re-Os isotopic chronology of molybdenite suggests that the metallogenic age of the Anqiantan tungsten ore deposit in south Jiangxi area within eastern Nanling region is about 156 Ma and that of the Yuanlingzhai molybdenum ore deposit is about 160Ma.Statistics indicate that there occurred 3 epochs comprising 6 stages of mineralization during Mesozoic in the eastern and central parts of the Nanling metallogenic belt.These stages are about 225 Ma and 195 Ma of Indo-Chinese period,170-160 Ma,160-150 Ma and 150145Ma of Early Yanshanian period,and about 135 Ma and 100 Ma of Late Yanshanian period.The mineralization during Early Yanshanian period is the strongest one,so that Early Yanshanian is the major metallogenic period for tungsten and tin ore deposits in the eastern and central parts of the Nanling metallogenic belt.There exist independent W-Sn polymetallic ore deposits,Sn ore deposits,Cu-Pb-Zn polymetallic ore deposits and Mo ore deposits.Combined with an analysis of metallogenic chronology,the authors hold that there might exist undiscovered or neglected mineral resources in the horizontal direction as well as metallogenic potential at the depth of the known ore deposits in the vertical direction.This study has provided theoretic basis for geological prospecting in the second space of the eastern and central parts of the Nanling metallogenic belt.