The Provenance Characteristics Analysis Of The Gequ Formation Of Upper Permian At The Buqingshan Area

The Gequ FormationMarine molassesedimentary combination in Buqingshan-Animaqing tectonic belt is an important sedimentary response to the northward subduction of the Paleo-TethysOceanat the Late Permian to the Early-Middle Triassic.In the study area,the Gequ Formation is mainly exposed in northern of Buqingshan area,including in Hongshuichuan,Tuosuohe and Delisitangou region.Based on thestudy of U-Pbgeochronology,tectonic geology and geochemistry ofGequ Formation in Hongshuichuan,Tuosuoheand Delisitangou region,this paper analysed the provenance characteristics of Gequ Formation.The awareness and conclusionsofthis paper are as follows.1.The detrital zircon U-Pb age by LA-ICP-MS were carried out on the samples from Hongshuichuan,Tuosuohe and Delisitangou areas.The age characteristics of the debris zircon in the three regions are as follows :(1)There are five age intervalsin the Buqingshan area: 335.9~578.5Ma,742.9~1192.4Ma,1318.7~1607.5Ma,2334.6~2496Ma and 2925.1~3143.7Ma,respectively.(2)There are five age intervals in the Tuosuohe area: 400.3~555.6Ma,723.5~1275.6Ma,1408~1547.3Ma,1696.3~1740.7Ma and 2479.1~2896.3Ma,respectively.(3)There are three age intervals in the Delisitangou: 409~499Ma,619~744Ma and 2443 Ma,respectively.2.The most important period of Gequ Formation provenance at the Buqingshan areais Caledonian period.In Hongshuichuan and Tuosuohe area(belongs to the north part compared to the Delisitangou),Neoproterozoic-Mesoproterozoic andPaleoproterozoic-Archean was appeared in the detrital zircon U-Pb age,while Delisitangou region only havethe Neoproterozoic to Mesoproterozoic,did not have thePaleoProterozoic to Archean.The northern Gequ Formationis earlier than the southern Gequ Formation.3.The Caledonian age information reflects the material source associated tectonic magmatic thermal events of the the the northward subductionof Proto-Tethys Ocean in Early Paleozoic.The magmatic arc formed by the subduction and collision is an important provenance for Gequ Formation.4.Neoproterozoic-Mesoproterozoic age information reflects provenance from the magma caused by the breakup of the Rodinia continental.5.Paleoproterozoic-Archean age information reflects the earliest regional tectonic magmatic thermal events in 2400~2500Ma when the crystalline basement was formed in Paleoproterozoic.