摘要
桂北地区的重磁场与铀矿化有着密切的联系，地球物理场的特征反映了与铀成矿有关的地质环境。研究表明，桂北地区的铀矿化主要有如下一些明显的特点；（ｌ）铀矿化位于不同规模的地球物理场或异常的边缘，尤其是大规模的铀矿化产在区域重力低异常（对应于地壳增厚区即地幔拗陷区）的边缘；（２）深部地质作用如莫霍面的起伏、深部大规模的岩浆活动和深断裂作用是铀成矿的重要控制因素；（３）花岗岩体不仅是花岗岩型铀矿化，而且也是碳硅泥岩型铀矿化的铀源体，且岩浆的动力场愈强烈，岩体的铀含量愈高，对铀成矿愈有利；（４）与铀成矿有关的热液流体为非岩浆成因，具有很强的去碰能力，花岗岩为热液循环提供动力；（５）与铀矿化密切共生的黄铁矿主要源于岩体的“磁性壳”；（６）铀矿床形成于中－低温、浅地表的地质环境。
Gravity and magnetic fields are intimately related to uranium mineralization in northernGuangxi region and characteristics of geophysical field reflect the geological environmentsrelevant to uranium metallogenesis. The study shows that uranium mineralization in northernGuangxi region mainly exhibit the following several obvious features: (1) uranium mineralization is located at the margin of geophysical fields or anomalies on different scale,especiallylarge-scaled uranium mineralization is present at the margin of regional gravity low anomalies(corresponding to the crustal thickening area,i. e. mantle depression area); (2)The deep geological processes such as the tilting and subsiding of Moho discontinuity, large-scaled deepmagmatism and deep faulting are main controlling factors for uranium metallogenesis; (3)Granitic bodies are not only the uranium source body for granite type uranium mineraliza-'non,but also for carbonate-siliceous-politic rock type uranium mineralization. Moreover,thestronger the magmatic dynamic field,the higher the uranium content in granitic bodies andthe more favourable for uranium metallogenesis j (4)Hydrothermal fluids relevant to uraniummetallogenesis are of nonmagmatic origin,having strong demagnetization capability and granite offered dynamics for hydrothermal circulation; (5)Pyrite closely associated with uraniummlneralization is mainly derived from'magnetic crust'of the granitic bodies; (6)Uranium deposits were formed in mesoepithermal, shallow surface geological environments.
出处
《铀矿地质》
CSCD
北大核心
1995年第3期147-154,共8页
Uranium Geology
关键词
桂北地区
成矿特点
铀源体
热液作用
铀矿床
Northern Guangxi region,Gravity and magnetic fields,Uranium metallogenetic characteristics,Uranium source body, Hydrothermalism
