| 北京市得田沟金矿床成因机制 |
| 点此下载全文 |
| 引用本文：.1996.The genesis of the Detiangou gold deposit, Beijing[J].Mineral Deposits,15(2):156~164 |
| Hits: 2402 |
| Download times: 1672 |
|
|
| 中文摘要:得阳沟金矿床产于太古宙四合堂群角闪岩相变质地层中。容矿围岩主要为角闪石岩、斜长角闪岩、片麻岩及变粒岩等。区域崎峰茶断裂（糜棱岩）带及边部次级（韧性）剪切带控制着金矿体的形态、产状。矿石以含金（含碲化物）多金属硫化物石英脉为主，其次为含金蚀变岩。矿床稳定同位素特征及金丰度的变化表明金与正长斑岩岩浆同源，来自地幔。成矿温度为70 ~490℃，峰值区为150 ~270℃；成矿压力为100～1500 MPa。在燕山中期 (147×106 a )，与正长斑岩同源的富金热流体贯入太古宙变质地层中相对封闭的韧性剪切带中沉淀成矿。 |
| 中文关键词:金矿床 矿质来源 成矿条件 成矿机制 得田沟 |
| |
| The genesis of the Detiangou gold deposit, Beijing |
|
|
| Abstract:The Detiangou ore deposit consists of gold-polymetallic quartz veins in Archean migmatized biotite leucogranulite, biotite leptynite, hornblende-biotite plagicolase gneiss, plagioclase amphibolite and hornblendite. The major ore veins are confined to the ductile shear zones near the ore-control fault. The ore deposit is a hydrothermal filling veinlike one. Syenite dikes are developed in the gold ore district. The gold abundance averages 23×10-9 in the metamorphic rocks, and 160 ×10-9 in the syenite dike. The mineralizing process formed in turn the following metallic mineral assemblages; ① pyrite + arsenopyrite; ② pyrrhotite + kappa-pyrite; ③ native gold + native silver + galena + chalcopyrite + bornite + tetrahedrite + altaite + acanthite + petzite + tellurbismuth + volynskite + rnolybdenite + hessite + sphalerite; ④ sylvanite + stuetzite; ⑤ native tellurium + unnamed minerals Mi+ M2+ M3+ M4+ anglesite. The host rocks have been subjected to pyritization, sericitization, chloritization, epidotization, actinolitization, tremolitization and silicification. The hydrogen and oxygen isotope data of fluid inclusions in quartz veins indicate that ore-forming fluids were mainly composed of magmatic water mixed with some meteoric water. The sulfur isotope composition (δ34S= -0.9‰~2.8‰ ) of sulfides from the ore veins is close to that of meteoric sulfur, suggesting that the sulfur came from deep magma. The ore lead isotopes are similar to lead isotopes of syenite dikes, indicating characteristics of mantle-derived materials. Ore-forming substances are also considered to have come from the mantle. Fluid inclusions in quartz from the ore veins are composed of Na+, K+, Mg2+, Cl-, SO42-, H2O and CO2, with an average salinity of 5 wt% equivalent NaCl. The altered rock of ore veins has a K-Ar age of 147×106 a, suggesting that the Detiangou gold deposit was formed in Middle Yanshanian period. |
| keywords:gold deposit, source of ore materials, metallogenic condition, Detiangou |
| View Full Text View/Add Comment Download reader |
|
|
|
