熊耳群火山岩形成的构造环境探讨

DISCUSSION ON THE STRUCTURAL SETTING FOR THE FORMATION OF THE XIONG'ER GROUP VOLCANIC ROCKS

熊耳群中基－中酸性火山岩系是熊耳山区最为重要的产金层，其形成时代大致相当于华北地区的长城系，为华北地台南缘结晶基底之上的第一套盖层沉积。多年来，中元古代早期华北地台南缘构造框架颇有争议。本文从熊耳群火山岩系的分布形态、与基底的接触关系、常量、微量元素特征、稀土之素特征诸方面证实了熊耳群火山岩系为典型大陆裂谷喷发的产物，并非陆缘火山岛弧成因。

The intermediate basic-intermediate acidic volcanic rock series in the Xiong'er Group isthe most important gold-productive formation in the Xiong'er Mountain area. Its formationtime is approximately equivalent to the Changcheng System in North China region and it isthe first suite of cover sediment on the crystalline basement at the southern margin of theNorth China Platform. In recent years, there has been much controversy on the tectonicframework of the southern margin of the North China Platform in the early period of theMiddle Proterozoic. From the aspects of the distribution pattern of the Xiong'er Group volcanic series, its contact relation with the basement, the features of major and trace elementsas well as rare earth elements, this paper has confirmed that the Xiong'er Group volcanic series resulted from typical continental rift eruption, and it is not of epicontinental volcanic arcorigin.