Mineralogical Study Of The Western Qinling In Gansu Potassium Xia Olive Yellow Long Rock

The Cenozoic kamafugitic rocks of Western Qinling in Gansu province are poor inSiO2, but rich in Mg, Ca, and alkalies the same as kamafugits reported by the othercountries. Kamafugitic mineral assemble is very complicated, but nearly nobodyhave reported about kamafugites from its mineralogy facet. Based on the earlysystematic geological, petrological and geochemical study, the paper carries outresearch on some newly-discovered outcrop of kamafugites in Western Qinling,mainly systematically studying the mineralogical characteristics of Kamafugites.These results will restrict the genesis and chemical compositions of kamafugites onmineralogy facet.The researches indicated that kamafugites consist of a set of special minerals,including phenocrysts phase olivine, clinopyroxene and phlogopite which havecommonly characteristics of multi-generations and multi-genesis, especially inclinopyroxene phenocrysts on broad chemical compositions range. The paperconformed chemical compositions of all minerals and classified minerals as detailedsorts by systematical electron-probe analysis on minerals of phenocrysts and mineralsin the groundmasses. Based on the study, we discuss the genesis of main minerals and significance ofrock genesis, and testify that the chemical compositions of kamafugitic minerals inthis region are restricted by the magma compositions and compositions variety duringthe process of magma evolvement. For example, clinopyroxenes commonly occurzones, and theirs compositions always evolve from diopside rich in Ca to rich in Ti,which is related with complexity of magma evolvement.Phlogopites are also rich in Ti which crystal under the environment of thehigh-pressure. So, the appearances of lots of Ti-phlogopites in igneous rocks canreflect that the magma came from the condition of the high-pressure and compositionof the volatile is a key role during the process of the magma genesis and evolvement.In addition, the kamafugitic groundmasses in this region develop microphenocrystsand microcrystals of the clinopyroxene or melilite, and their interspaces are full ofnepheline(kaliophilite), leucite, calcite, apatite, perovskite, zeolite, and so on. Theseminerals are rich in alkalies and compositions of the volatile which reflect theevolvement tendency of the magma in this region to enrichment in alkalies...