密怀隆起——我国早前寒武纪古陆壳的重要研究基地

Mihuai Uplift——An Important Research Base for the Early Precambrian Continental Crust in China

早在20世纪30年代初,密怀隆起已被我国地学者所关注。50年代末60年代初,北京地质学院区调队1:5万填图确认,组成该隆起的古老变质片麻岩是火山-沉积岩,属于太古界。80-90年代,引进国外先进变质岩理论,区测过程,产生严重对立。持新观点者认为,隆起的绝大部分片麻岩是块状无序的变质侵入岩。持传统观点者认为,这些片麻岩是变质的表壳岩。认识陷入世界性难题的争议之中。90年代初,全国开展地层清理。北京采用新观点认为,未发现密怀隆起存在面型的表壳岩,因此,原来隆起划分的两大群地层失去了加入《中国地层典-太古宇》的机会。世纪末,陈台沟表壳岩的发现,给人以启发。比较而言,陈台沟表壳岩面积很小,但是,工作程度较高,依据较充足,受到点赞。密怀隆起有两套表壳岩,大个体,特点多,信息量大,尚有许多线索有待破解,具备古陆壳研究基地的许多有利条件。

In the early 1930s,the Mihuai uplift had been concerned by scholars in China.In the late 1950s and early 1960s,the1:50000 geological mapping by Beijing College of Geology confirmed that the ancient metamorphic gneiss in the uplift was the Archaeozoic volcano-sedimentary rocks.In the 1980-1990s,the metamorphic theory was introduced to produce new view about the metamorphic rocks.The new view holds that most of the uplifted gneiss are massive and disordered metamorphic intrusive rocks.The traditional view considers that the gneiss belongs to metamorphic supracrustal rocks.In the early 1990s,the strata reorganization was carried out throughout the country.According the new view,the Mihuai uplifted gneiss has not been listed into Chinse Stratigraphy Code?Archean Eonothem.At the end of the century,the metamorphic supracrustal rocks have been discovered at Chentaigou,which give people some inspirations.Although the Chentaigou supracrustal rocks occupy the small surface areas,they has the high-degree research,and the recognition is supported by enough evidences.There are two sets of supracrustal rocks in the Mihuai uplift,which will be the research base of early Precambrian continental crust.