摘要
对陂头一带风化壳淋积型稀土矿点进行野外调查和室内综合研究表明:变质基底层、岩浆多期活动和岩浆期后脆性断裂构造活动是风化壳淋积型稀土矿的形成主因。变质基底构造层中泥质板岩、炭质板岩和变凝灰质砂岩中RE2O3含量高,在岩浆侵位过程中带入了大量的稀土元素,在含矿母岩顶部可见大量的未熔完全的基性捕掳体。受后期热液交代蚀变,导致含矿母岩中长石矿物粘土化强烈,对水具有胀缩性,易碎岩成矿。岩浆期后"X"型脆性共轭剪切断裂为雨水渗漏贯通提供了良好的通道。含矿母岩在各个地质历史阶段受古气候多次变化的影响加速了含矿母岩的风化程度。表土层的保湿渗水呈酸特性促进了稀土矿的形成。区内变质基底炭泥质板岩和变凝灰质砂岩、岩浆期后脆性断裂、含基性捕掳体的红褐色黑云母二长花岗岩是风化壳淋积型稀土矿的地质宏观找矿标志。
The field investigation and laboratory analy- sis indicated that the metamorphic basement, multi- stage magmatic activity and postmagmatie brittle faults are main factors of rare earth deposition in Pitou re- gion. Argillite, carbonaceous slate and metamor- phosed tuffaceous sandstones of metamorphic basement contain higher concentrations of RE203, which took into a large number of rare earth elements during the magmatic emplacement. Many incompletely melted mafic xenoliths were observed at the top of ore-bearing rock. Affected by post hydrothermal metasomatic alter- ation, feldspar of granites occurred strong clayization with character of swelling and shrinkage and easily broken to form rare earth. The postmagmatic ＂X＂ type conjugate shear brittle fracture activities provided a good leaking channel for meteoric water. The chan- ges of paleoclimate had accelerated the weathering of ore-bearing rock in different stages of the geological history. The moisture water seepage in surface soil was acidic, which promoted the mineralization of rare earth. The charcoal argillite and metamorphosed tuf- faceous sandstones in metamorphic basal, postmagmat- ic brittle faults activity and reddish-brown biotitic granite with mafic xenoliths were obvious prospecting indicators.
出处
《中国稀土学报》
CAS
CSCD
北大核心
2014年第1期101-107,共7页
Journal of the Chinese Society of Rare Earths
基金
中国地质大调查项目(1212011120813
1212011120811
1212010881305
1212010533003)资助
关键词
风化壳淋积型
稀土矿
古气候
南岭
燕山期
weathered crust elution-deposited
rare earth ore
ancient climate
Nanling
Yanshanian
