The Lithogeochemical Characteristics And Protolith Formation Of Khondalite Series In Daqingshan Region, Inner Mongolia

Reconstruction of early palaeo-continent, properties and evolution of earlycontinental crust has become one of significant front problems of contemporarygeoscience. But the Khondalite series is a suit of characteristic metasedimentary rockseries in the high-grade metamorphic region in early continental crust development. Theresearch of its characteristic and research of origin has important scientific significant forprobing into the evolution process of the early continental crust formation of this typeregion. Daqingshan region of Inner Mongolia is one of regions that Khondalite series mainlydeveloped in China. A great quantity of study work had been done by formerresearchers accumulated rich geological data a great quantity of papers and monographswere issued. But they didn't pay more attention to a suit of metamorphic deposit strataconsist of calcium silicate developed in the Daqingshan region, Inner Mongolia, becausethey distributed discontinuity outcrops in else region. But the most research of origin ofkhondalite series had been done for quartzite, sillimanite garnet gneiss and graphitegneiss which represent obvious rock association of original strata component ofkhondalite series. But the calcium silicate rock assemblages which is one of main rockcomponent of khondalite series ( In case calcium silicate, dolomite-marble etc. ), yetseldom systematically researched. But the calcium silicate rock assemblages areimportant significant for systematically researching protolith formation, the tectonic IV英文摘要environment and evolution of depositional basin and the characteristics of earlycontinental crust of the Precambrian. The paper basis on sufficiently to former data and research achievements find outthe distribution in space, the characteristic of rock composition, stratigraphic sequence,lithogeochemical characteristics, protolith formation of this suit of khondalite serieswhich developed in the Daqingshan region, Inner Mongolia, by systematically analysisresearching. The protolith formation has been restored based on lithogeochemicalcharacteristics and varied protolith recovery diagrams, further discussing about types ofprotolith formation and depositional environment of protolith of this suit of khondaliteseries. Below knowledge acquired Widely developed metamorphic strata in researching region is the characteristicobviously typical region of metamorphic strata of early Precambrian distribute widely inthe middle-west part of Inner Mongolia. Khondalite series in the studying region widelydeveloped they were divided into three rock groups basis on the characteristic ofpetrology: garnet biotite gneiss rock group, diopside gneiss rock group and marble rockgroup, they compose relevant member of rock component within strata sequence. Thespace relationship among three groups are closely links they are interbedded orinterlayers in most output contacted by the structural relationship among every rockgroup extending near east to west in striped for majority. The khondalite series in thelocal region are discontinuity outcrops, presenting irregular in block likely, patch shapeand lens shape. The stratigraphic sequence of three rock groups of this suit of khondalite series frombottom to top are Garnet biotite gneiss rock group, diopside gneiss rock group and marble V英文摘要rock group. The garnet biotite gneiss rock group is one suit gneisses series of rich in aluminum.It is character of rich containing garnet, sillimanite and cordierite etc.. The main rocktypes are garnet biotite gneiss, graphite ( Garnet ) Gneiss, garnet felsic gneiss ( lightgranulite ) etc. Its lithogeochemistry is character of rich in aluminium, iron, magnesiumand deficient in calcium and alkali. Al2O3 presents obvious negative correlation againstSiO2, presenting continuously geochemistry sequence between clay r...