Font Size: a A A

Characteristics And Tectonic Setting Of Acid Volcanic Rocks In Early Cretaceous Baiyingaolao Formation From Keyouzhongqi Area, Inner Mongolia

Posted on:2015-03-10Degree:MasterType:Thesis
Country:ChinaCandidate:Y M KongFull Text:PDF
GTID:2250330428490884Subject:Mineralogy, petrology, ore deposits
Abstract/Summary:PDF Full Text Request
The author studied the geology, geochemistry, zircon U-Pb ages, the Hf isotopeof Baiyingaolao Formation volcanic rocks and its petrogenesis and tectonic setting inthe studied area. The studies will be signification in discussion of regional tectonicevolution in Da Hinggan Mts..The LA-ICP-MS zircon U-Pb dating result of Baiyingaolao Formation acidvolcanic rocks is121.5±1.0Ma, indicating that the acid volcanic rocks were formed inlate Early Cretaceous.The acid volcanic rocks are high-SiO2and alkali-rich, which belongs to high-Kcalc-alkaline series rocks (A/CNK=0.95%-1.25%). All the samples are characterizedby enrichment in LILE such as Ba, Th, U, K and Gd, depletion in HFSE like Sr, Nb,Ta, Ti, etc., suggesting the primary magma were derived from partial melting ofcrustal rocks. In104×Ga/Al-FeOT/MgO, Zr, Nb, etc. diagram, all the samples fall intoI-type granite distribution area, showing the characteristics of high-fractionated I-typegranite.In Harker diagram, the samples of Baiyingaolao Formation acid volcanic rocksshare a well linearity similar, indicating that these samples have similar magmasources. Combining with regional tectonic settings, it can be conclued that theformation of the acid volcanic rocks in the studying area were related with thecombination of collision-orogenic environment and post-orogenic extensionalenvironment which causing an extensional tectonic background. This tectonic settingmight be related to the subduction of Pacific plate.
Keywords/Search Tags:Da Hinggan Mountains, Baiyingaolao Formation, acidic volcanic rocks, EarlyCretaceous, zircon U-Pb dating, geochemistry
PDF Full Text Request
Related items