摘要
本矿床是燕山期的热液充填-交代脉状铅-锌-银矿床。其中伴生有综合利用伤值的金、银。金、银主要呈微粒自然金、银金矿、脆银矿、螺状硫银矿、深红银矿、黝锑银矿和自然银产出。金矿物常与辉铋铅矿、自然铋、未命名的Bi_2Te矿物相伴生,包裹于或充填于黄铁矿、铁闪锌矿、含铁闪锌矿和方铅矿的微裂隙中。银矿物通常产于方铅矿、铁闪锌矿和黄铁矿的解理或裂隙内,但不与金、铋矿物伴生。金、银矿化晚于铅、锌矿化,而金矿化相对早于银矿化。
The deposit consists of lead-zinc veins, of which the majority dip deeply in the hornblende-biotite-plagioclase granulitites of the Lower Proterozoic and a few occur in the pyroclastic rocks of the Upper Jurassic that unconformablly overlie the granulitites. These veins are commonly controlled by fracture systems derived from the ore-controlling fault zone F_(45) The deposit is a hydrothermal filling-metasomatic vein deposit of the Yanshanian.
Ore minerals are chiefly marmatite (Fe≥8%), iron-bearing sphalerite (Fe 8—2%), sphalerite (Fe<2%), galena and pyrite, with a small amount of arsenopyrite, marcasite, chalcopyrite, hematite and siderite, as well as minor gold, silver and bismuth minerals. Gangue minerals are quartz, calcite, chlorite, sericite, actinote, etc.
The lead-zinc ores contain 0.0—11.45 g/t Au (averaging 0.51 g/t), 1—1013.4 g/t Ag (averaging 24.40 g/t), 140—761 ppm Cd and 22—250 ppm In. The contents of the main and minor elements for the principal sulfide minerals are shown in Table 1, and these minerals commonly comain Au, Ag, Bi, Cd, In, etc. But such elements vary greatly in content, which is chiefly related to the nonuniform distribution of Au-, Ag-, and Bi-minerals in the sulfide minerals. The Cd and In occur as isomorph in three sphalerites, whereas the Au, Ag and Bi are present chiefly in the form of fine-grained minerals which are native gold, electrum (see Table 2), acanthite, stephanite, pyrargyrite, freibergite (see Table 3), native bismuth, unnamed Bi_2Te mineral, galenobismutite and heyrovskyite (see Table 4). Native gold and electrum occur together with bismuth minerals either as inclusions in galena, marmatite, Fe-bearing sphalerite and pyrite or as fillings in microfissures of these minerals (Plate Ⅰ, 1—4), whereas silver minerals often fill fissures of the sulfides (Plate Ⅰ, 5—8), suggesting that the mineralization of gold, silver and bismuth was slightly later than that of lead-zinc. It is considered that during the formation of the deposit, the
出处
《地质学报》
EI
CAS
CSCD
北大核心
1991年第2期127-140,T001,共15页
Acta Geologica Sinica
