摘要
希望铀矿床为热液铀矿床。本文中主要探讨了热液中水、铀和∑CO_2的来源。研究表明,水、铀和∑CO_2各有不同的来源:初始热液中的水是花岗岩浆分异出的岩浆水(后有大量大气降水混入);成矿热液中的铀主要取自自云母花岗岩中的活性铀;成矿热液中的∑CO_2主要由煌斑岩岩浆提供。
The Xiwang deposit is a large-sized hydrothermal uranium deposit located in shattered zones of a granite body. Rocks in the ore district and the neighboring areas include mainly the U-rich Yanshanian granite (193—138Ma) formed by remelting of the sialic crust and the ΣCO_2-rich mantle-source lamprophyre (110—100Ma). Pitchblende (90—85 Ma) seems to be the only primary uranium mineral, which is associated with quartz, fluorite, hematite and pyrite.Based on geological investigation in the' field and large quantities of analytical data, this paper, applying integratedly theories and methods of such disciplines as basic geology, isotopic geology, geochemistry, physicochemistry and statistic mathematics, discusses mainly the sources of water, uranium and ΣCO_2.Our studies show that these three sorts of substances were derived from different sources: the water in the initial hydrothermal fluids came from granitic magma mixed later with a large amount of meteoric water; the uranium in the ore-forming hydrothermal fluids was mainly active uranium derived from the muscovite granite which was either a primary rock body or formed through autometamorphism of a biotite granite; the ΣCO_2 in the fluids was chiefly provided by the lamprophyre magma. It is pointed out that the areas where the ΣCO_2-rich mantle-source lamprophyre penetrated after the intrusion of the U-rich crust-source granite are especially favorable for the formation of granite type hydrothermal uranium deposits.
出处
《矿床地质》
CAS
CSCD
北大核心
1990年第2期141-148,共8页
Mineral Deposits
