两广云开区震旦纪硅岩建造的岩石学特征及成因  

PETROLOGICAL FEATURE OF THE SINIAN CHERT FORMATON AND ORIGIN IN YUNKAI AREA, GUANGXI AND GUANGDONG

作　　者：周慧杰[1] 吴丰元 吴家勇 

机构地区：[1]广西师范学院地理系,南宁市530001 [2]海南省地矿局,海口571158 [3]广东省廉江银矿,廉江528300

出　　处：《广西师院学报（自然科学版）》1999年第3期5-9,29,共6页Journal of Guangxi Teachers College(Natural Science Edition)

摘　　要：地处粤西和桂东南的云开地区前寒武系顶部的硅岩沉积建造（“震旦系Ｄ 组”），具有层状、纹理状、块状和假角砾状构造。其中的元素显著地贫ＴｉＯ２ 和Ａｌ２Ｏ３， 大部分微量元素相对于地壳克拉克值亏损， 但Ｂａ、Ｓｂ、Ｈｇ、Ａｇ 和Ｂｉ等少数几种元素例外地富集； 在Ａｌ－ Ｆｅ－ Ｍｎ 三元图中投影落在热水沉积区域； 以ＲＥＥ总量低为特征， 平均稀土元素分布型式落在世界上已知典型热水沉积物的上、下限之间。上述特征说明， 该硅岩建造是典型的热水沉积成因产物。The Sedimentary chert formation (Sinian D fromation) at the top of the Precambrian in Yunkai area,western Guangdong and southeastern Guangxi displays banded,lamellated,massive and pseudobrecciated structures.This formation is poor in TiO 2 and Al 2O 3 with most of the trace elements depleted in relation to their clarke values,although a few including Ba,Sb,Hg,Ag and Bi are exceptionally enriched;in Al-Fe-Mn triangular diagram,the sample points fall into the hydrothermal sedimentary field;total REE is characterized by low value and the average REE distribution pattern conforms with those of the worlds typical hydrothermal sediments.All these features are indicative of a typical hydrothermal derivation.

关 键 词：岩石学特征 热水沉积 震旦纪 成因 硅岩 

分 类 号：P588.244[天文地球—岩石学]