【摘要】 <正> 凤太矿田,位于秦岭中段,陕西省凤县至太白一带。西接“西成矿田”;东邻“柞山矿田”。属秦岭泥盆系多金属、铁成矿带的一部分。本区铅锌矿产丰富,已经发现矿床、矿点数十处,其中大中型矿床四处。对于矿床成因,前人多认为属“中低温热液矿床”。随着工作的不断深入,发现凤太矿田内之铅锌矿体,主要赋存于中泥盆统古道岭组上岩段与星红铺组地层界面附近,严格受此地层层位控制;矿体形态多呈层状、似层状分布,沿走向和倾向均较稳定,矿体与围岩产状基本一致,多呈整合接触;矿石中矿物组份简单,主要金属矿物为闪锌矿、方铅矿;矿石中见有浸染状、胶状、条带状、细纹状等原生沉积作用所形成之构造残余;矿田内岩浆岩不发育,而且矿体空间分布和岩更多还原

【Abstract】 The ore field richin Pb zn ore deposits in the Fengxian-Taibai counties is located in the middle of the Qinling Mts.. The orebearing bed mainly exists in the transitional sedimentary beds between the Gudaoling Group and the xinghongpu Group of the Middle Devonian Series. It can be divided into two ore-bearing beds. The upper bed is the predominant one, forming the huge and the medium-sized ore deposits in this area.This paper briefly deals with the distribution of the sea and the land, the sea floor reliefs, the hydrodynamic conditions and the physico-chemical conditions during the sedimentary period of the main ore-bearing bed of the ore field in the Fengxian-Taibai counties. By the texture analysis section, it describes the evolutionary process of facies from the platform marginal shoal facies to the platform marginal bioherm facies-the localized platform facies-the platform marginal shoal facies-the platform marginal bioherm facies of the Middle Devonian (Lower Givetian) since the ore field is divided into two along the South-north line of Hetaoba, we have found a marked difference of the ore-forming characteristics between the east and the west of the ore field. The geographical distribution of some huge and medium-sized ore deposits clearly shows that the restricted environment forming the barrier island of the bioherms is favorable for the ore-formation. The field work has proved that the distribution of ore deposits is controlled by the barrier island of the bioherms in the neighboring region of the Weiziping. The ore-bearing bed was formed at the end of the two reef-building periods during the Middle Devonian (Lower Givetian), and the formation was closely related to the bioherms. Thus, the advantageous foundation was provided for the ore beds of later concentration under all kinds reconstruction process. In a word, the ore field in the Fengxian-Taibai Counties belongs to a kind of the strata-bound ore deposits, and some promising areas have been indicated in further prospectings.更多还原