| The thesis is based on the research of predecessors and the analysis of regionalgeological background, through the field geological survey and the geologicalinterpretation of the SPOT remote sensing images, by the means of mineralogy,lithogeochemistry, the main and trace element analysis, LA-ICP-MS Zircon U-Pbdating and Sr、Nd、Pb isotope geochemical tracer technique and some other means, thepaper has systematicly studied the intrusion classcification of the rock mass, thepetromineralogy characteristics, lithogeochemistry characteristics, the genetic type,the tectonic environment and the material source of Archie mountain NO.1granitemass. Mainly obtained the following understanding：Archie mountain NO.1granite mass belongs to the mesogenetic large granitebatholith, which formed by multiple pulsation intrusiving, and the rock mass is madeup of8intrusions. The mainly lithology is syenogranite, alkali feldspar granite and(biotite)monzonitic granite. And syenogranite was emplaced earlier than the(biotite)monzonitic granite. The geological evidence and the zircon U-Pb datingresults show that the rock mass formed in middle Permian.The study on mineralgical and petrochemical shows that, the composition ofArchie mountain NO.1granite mass is homogeneous, the contexture is simple. Therock mainly be mesograin and granitic texture. The alteration is weak, and themicrostructure of the rock was not growing.The analysis of rock geochemical data indicates that, Archie mountain NO.1granite mass should be calc-alkalic, metaluminous-weakly peraluminous I typegranite, and also enriching silicon, alkali, potassium. The degree of magmaticdifferentiation of syenogranite and alkalic feldspar granite is higher than biotitemonzonitic granite.The Chondrite-normalized REE pattern of the dikes samples is the right dipping,which enriching LREE（light rare earth elements）.The fractionation of light and heavyrare earth element is less obvious; At the same time, the negative anomaly of Eu ismuch more obvious.The spidergram of trace element shows that all intrusions of therock mass concentrating K, Rb, Th, U, Pb,deficiting the high field strength elementssuch as Nb、Ta、P、Ti、Zr and several large ion lithophile elements such as Sr,Ba,shows the material source of the rock mass has continental crust characteristics. Sr, Nd, Pb isotopic data and some other data shows that the rock mass should be Itype granite, formed in within-plate stage of postorogenic tectonic environ-ment.Thegenesis of Archie mountain NO.1granite mass are related to continental crust verticalgrowth caused by young mantle magma invasion. The materail source mainly be thepartial melting of crustal materail accompanied by the contimanation of themantle-drived material.The lower Isrvalue (0.70442～0.70553) shows mantle characteristics, higher εNd(t)value(0.4831～3.6683) and younger TDM(850～1346Ma) indicating the source ofArchie mountain NO.1granite mass was the younger crust derived from the depletedmantle.Based on the above studies, the composition of Archie mountain NO.1granitemass is uniform, and the structure is simple. The rock mainly be mesograin andgranitic texture, the alteration is weak. And the rock mass formed in within-platestage of postorogenic tectonic environment, the age of all the intrusive mass is closer.Since the invasion of the territorial diabase prophyrite, the East Tianshan areas tend tocratonization, thermal activity is reduced, Archie mountain NO.1granite mass neverexperienced a strong regional tectonic activity, the integrity of the rock relativelypreferable, so it’s the applicable location for sit selection of high-level radioactivewaste. |
PDF Full Text Request