Study Of Early Paleozoicintrusive Rocks In Yakeshi Region,Inner Mongolia

The study area is located at Aershan City and Yakeshi City of the eastern part of Inner Mongolia which belongs Xingmeng Paleozoic tectonic units of Xing'an orogenic belt land.This paper studies the Early Paleozoic intrusive rocks and geochemical characteristics of the rocks and discuss their origin and tectonic significance.After the discovery of geological investigation in the area,we can find the area belongs to Early Paleozoic intrusive which lanes north-east zonal distribution in mountain cliff – Halaha river and north west of the fault zone.The geological characteristics of intrusive and zircon U-Pb dating show that the invasion is during the Early Paleozoic Late Ordovician-Early Silurian(457Ma-427Ma).The main intrusions are Sudeerqigan and Wunuer,it includs quartz diorite,granodiorite and monzonitic granite which belong to I type granite.The REE concentration and light REE fractionation are high,and lack of Eu anomaly.Strong incompatible elementsenriched,but Ba,Nb,Sr,P and Ti is deficited,as the island arc granite shows.The concentration of alkaliin some granodiorite and monzonitic granite is high,but the concentration of REE is low,and the fractionation of LREE and HREE is strong,the negative anomaly of Eu is obvious,as the transition of S and A type granite.The average temperature of intrusions is 779.41?,as the low temperature granite associated with subduction.Early Paleozoic intrusive rocks in the area of spatial distribution,emplacement age,property and tectonic setting indicates that the formation of intrusive rocks are-closely related to Halaha Hebei and the cliff collage band.It shows that the presence of early Paleozoic oceanic basins reflect and direction,which provided an important basis for the interaction of Xing'an and Songnen terrain.They build a multi Baoshan continental margin arc together in the study area with the early Paleozoic intrusive rocks and early Ordovician volcanic arc of diagenetic Duobaoshan group.Comparing with the Hebei combining Halacha-ophiolite cliff collage band distribution mélange,it expands to ocean crust in about Middle-Later Cambrian.In the Cambrian late,the northward subduction of oceanic basin formed Duobaoshan continental margin arc of the Ordovician.In the late Silurian,,the formation of The Halacha Hebei-cliff collage band were formed with the ongoing subduction of Xing'an land and Songnen terrain collision.