东坪金矿金质来源与张宣地区花岗岩-绿岩地体的关系探讨  

RELATIONSHIP BETWEEN THE GOLD SOURGE OF DONGPING GOLD DEPOSIT AND ARCHEAN TIG-GREENSTONE BELT

作　　者：李长民[1] 

机构地区：[1]天津市国际商务学校,天津300250

出　　处：《前寒武纪研究进展》1999年第1期40-46,共7页Progress in Precambrian Research

摘　　要：河北省张宣地区的东坪金矿赋存于水泉沟碱性杂岩体与太古宙花岗岩一绿岩地体的接触带附近岩体一侧，是与碱性若有关的新型金矿床。通过对该区岩石的含矿性、稀土元素.Sr同位素等方面的研究，认为东坪金矿的形成与花岗岩一绿岩带的活化再造作用有关。其金质来源除幔源外，还有部分来自碱性岩形成时花岗岩一绿岩地体的重熔。含金质高的花岗岩一绿岩地体熔入岩浆后，随碱性岩的演化而富集，在岩体边部的构造有利部位形成超大型金矿。这类矿床与绿岩带的发展演化有关，属于与碱性岩或减质交代岩有关的绿岩带型金矿床。Dengping gold deposit in the northwestern Hallei province, China is a new type of Gold ore with super large in scale. It was discovered at first time in China. Situated at the western sector of Yanshan Mountain range, boping gold field is tectonically locates at thern side of the conact sone of Inner Mongolia Axis to the north and Yanshan Depressdri to the south along the northern margin of North China Platform. The hOSt rocks in the area are Shuiquangou alkaline comlex and Arallean TTG - greenstone belt. boping gold deposit occurs just at the inner contact zone of the two kinds of rocks conroled by the late fracture. The greentone belt,consisting of middle to high grade metamorphic rocks, contains rather high gold(about 4O X 1O -9~9 × 10(-9)), to be considered as source rock of the gold deposit. It provides part of gold during its remelting . Shuiquangou alkaline complex invaded into Archean TTG - greenstone belt in several periods. Maybe the first perbo is at about 410 Ma (single zircon U-Pb), and the Inaor period at afout 275 Ma (Ar-Ai). The comPlex is tnade of a series of rock types, such as monzonite, syenite and alkaline Syenite etc., and evolutes from fomer to later. The gold ore directly occurs in the alkaline syenite with strong wall-rOCk alteration.In this paper, the source of the gold is discussed. We suggest that the gold mostly comes from the greenstone. During the formation of the alkaline comPlex, there was abeut more than half matieral coming from the remelting of the TTG - greenstone rocks. The gold in the greenstone can be activated into the magrntic melt, and got richer and richer with the evolution of the comlex. At last, it depssited at a suitble place to form the large gold deposit. It belongs to the Post-tectonic regenerated hydrotheml gold deposit in the greenstone belt.

关 键 词：金矿床 金质来源 花岗岩 绿岩 地体 张宣地区 

分 类 号：P618.510.5[天文地球—矿床学] P588.121[天文地球—地质学]