湖南枞树板铅锌矿区构造特征及控矿条件研究

STUDY ON THE STRUCTURES OF THE ZONGSHUBAN AREA, CHENXIAN,HUNAN PROVINCE AND ORE CONTROLLING CONDITIONS

枞树板铅锌矿处于ＥＷ向山河复背斜和ＳＮ向西山复背斜复合部位。围岩为震旦系浅变质碎屑岩。ＮＥ向压扭性断裂是铅锌矿体的控矿及赋矿构造，富矿体产在控矿断裂较宽大且较破碎的部位，受构造透镜体控制；富矿体长轴向ＳＷ侧伏，侧伏角５０°—６０°，长宽比为２∶１，出露标高向ＳＷ次第降低呈斜列之势；稀土元素、微量元素和硫、铅同位素特征显示成矿物质主要来自千里山花岗岩，成矿时代为燕山早期（１５５—１７０Ｍａ），成矿温度１６８—２４４°Ｃ，属岩浆期后中低温热液矿床，是千里山岩体岩浆成矿系列（东坡矿田）的组成部分。花岗斑岩脉晚于铅锌矿脉侵位于ＮＥ向断裂中，局部穿切并破坏矿脉。区域上成矿、找矿有利部位是燕山早期小岩体周围或地下３—５ｋｍ处并有隐伏岩体发育的地区。

Zongshuban Pb Zn deposit occurs in the eastern part of Chenxian where the E W trending Shanhe anticlinorium meets with the S N trending Xishan anticlinorium.The country rocks of the deposit is Sinian epimetamorphic detrital rocks.The NE trending compresso shear faults are the important ore controlling structures.There develop some ore shoots in the strong kataclastic rocks in the fault zone.Individual ore shoot is lenticular,with the major/minor axis ratio of 2 to 1,and the major axis pitching to southwest at an angle of 50°-60°.Ore shoots are often en echelon arranged,one overlapping the other in longitudinal section from northeast to southwest along the mineralization zone.The metallogenic elements are derived mainly from the Mosozonic Qianlishan granite as indicated by the data of REE,microelements,sulfur isotope and lead isotope.The metallogenic temperature is determined as 168-224℃ and metallogenic period as 155-170Ma.It is therefore a postmagmatic meso and epithermal deposit,one of the magmatic metallogenic sequence of the Qianlishan granite (Dongpo polymetallic orefield).The granite porphyry emplaced into the NE trending faults is younger than the Pb Zn metallogenesis and was found to cut and disrupt the ore veins.Thus the area around the early Yanshanian granite stock (or a buried granite at a depth of 3-5km) is most favorable for further exploration.