NEW GEOLOGICAL EVIDENCES FOR THE FORMING AGE OF WUSINIHEI OPHIOLITIC MÉLANGE IN INNER MONGOLIA
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摘要: 贺根山-乌斯尼黑蛇绿混杂岩带的属性和形成时代存在明显的认识上的分歧.早期认为是二叠纪侵入的超镁铁质岩体.该超镁铁质岩体侵入了下二叠统格根敖包组，并被哲斯组地层不整合覆盖，形成时代为二叠纪.20世纪80年代以来，通过中国北方板块构造研究，在硅质岩中采集到的一系列化石资料表明，贺根山地区蛇绿混杂岩的形成时代应为中-晚泥盆世或更早.笔者在野外调查过程中发现，蛇绿混杂岩顶部的古风化壳及晚石炭世-早二叠世格根敖包组不整合于其上，因此认为乌斯尼黑蛇绿混杂岩带的形成不晚于晚石炭世.Abstract: Arguments remain on the structure environment and forming age of the Hegenshan-Wusinihei ophiolitic mélange. It used to be considered the ultramafic intrusive rock into the Permian Gegenaobao formation, covered unconformably by Zhesi formation. Since 1980s, with the discovery of radiolarian fossils in associated silicalite, the ophiolitic mélange was dated Early-Middle Devonian or earlier. During field survey, the authors found paleo-weathering crust on the top of the rock series and disconformity between the ophiolitic mélanges and Gegenaobao formation of Late Carboniferous-Early Permian. Therefore the ophiolitic mélange should be formed before Late Carboniferous.
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Key words:
- ophiolitic mé /
- langes belt /
- paleo-weathering crust /
- unconformity /
- forming age /
- geological evidence /
- Wusinihei in Inner Mongolia
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