豫西偃龙地区本溪组含铝岩系的结构特征

Texture Characteristics of Al-bearing Rock Series of Benxi Formation,Yanlong District,Western Henan Province

目前普遍认为,铝土矿是原地沉积的原岩经不同程度的降解作用所致,但从这一出发点对铝土矿的结构研究尚不深入。以豫西偃龙地区本溪组含铝岩系钻孔岩芯为研究对象,运用钻孔岩芯观察、偏光显微镜、扫描电镜和能谱分析等研究方法对含铝岩系的结构进行研究。研究表明,偃龙地区本溪组含铝岩系上下部的铝土质泥岩中残余颗粒发育,主要为交代残余结构;中部豆鲕(碎屑)状铝土矿中,撕裂颗粒、豆鲕粒发育,主要为豆鲕结构和碎屑结构,并伴随有流动现象。含铝岩系不同层位结构的差异主要与原岩的降解程度有关。

At present, it is generally believed that the bauxite deposit is caused by degradation in various degree of the original rock in situ deposition, but the research on the texture of bauxite is not thorough from this point of view. Taking the Al-bearing rock series coring in Benxi Formation as study sample, located in Yanlong area, Western Henan, the texture characteristics of Al-bearing rock series have been analyzed by core observation, The results show that residual particles are mainly enriched in the upper and lower bauxitic mudstone of Al-bearing rock series in the Benxi formation located in Yanlong area, which is mainly metasomatic relict texture. Tearing particles, pisolites and oolites are mainly enriched in the middle pisolitic-oolitic(clastic) bauxite, which is mainly pisolitic-oolitic texture and clastic texture, accompanied by flow phenomenons. The differences in the texture of different layers of Al-bearing rock series are mainly related to the degree of degradation of the original rock.