摘要
在对黔中花溪灰岩风化壳原地风化残积特征进行了论证的基础上 ,本文从地球化学角度对碳酸盐岩风化壳岩 土界面发育特征及其形成机理进行了讨论。碳酸盐岩的易溶解性和显著的差异性溶蚀 ,导致了其风化壳基岩面起伏强烈、岩 土界面界线清楚且突变 ;与此宏观特征相对应的是风化产物在矿物成分、主量、微量元素等方面均存在明显的突变现象。同时 ,在岩 土界面土层中形成了一个相对狭窄而突变的碱性障 ,此障无疑对风化壳的一些地质地球化学过程产生强烈影响 ,例如硅酸盐矿物的进一步蚀变分解 ,以及稀土和其它部分微量元素的超常富集和强烈分异等。
On the basis of field observation, mineral and geochemical investigation, the jeltozem profile at Huaxi, Guizhou Province, was considered as an in situ weathering crust derived from Triassic limestones. In virtue of low content of insoluble residues and easy dissolution of carbonate rocks, there are lots of unusual geological characteristics during the weathering and soil formation processes of carbonate rocks, such as remarkable volume decrease, uneven base rock surface, clear and sharp rock soil interface, and so on. Several unusual geochemical characteristics at or near the rock soil interface were discussed in this paper. A sharp change in pH value can be found in the soil layer near the interface because of the presence of calcite and its quick dissolution. Superhigh enrichment and strong fractionation of REE occurred near the interface because of the alkaline barrier. In addition, sharp changes in mineral composition and major elements can be found, too.
出处
《矿物学报》
CAS
CSCD
北大核心
2002年第2期126-132,共7页
Acta Mineralogica Sinica
基金
国家自然科学基金 (批准号 4 98330 0 2 )
中国科学院知识创新工程项目 (KZCX2 -10 5)
中国科学院"西部之光"资助项目
关键词
碳酸盐岩
风化壳
岩-土界面
地球化学
碱性障
贵州
形成机理
carbonate rock
weathering crust
rock soil interface
geochemistry
alkaline barrier
Guizhou Province
