Full-Text Search:
Home|About CNKI|User Service|中文
Add to Favorite Get Latest Update

CRUSTAL EVOLUTION IN ANHUI:Nd AND Sr ISOTOPIC EVIDENCE

CHEN Jiang feng, XIE Zhi ,ZHANG Xun, ZHOU Tai xi(Department of Earth and Space Sciences,University of Science and Technology of China ,Hefei 230026,China)  
Geochronological and Nd and Sr isotopic work on crustal and tectonic evolution of southern Anhui,including the Dabie and Jiangnan orogenic belt,was reviewed in this paper.Mid Proterozoic Shangxi Group low grade metamorphic rocks exposed in the southern margin of the Yangtze block represent the basement of the region.However,the basement of the region along the Yangtze River and the Dabie Mountains contains Archean and /or Paleo Proterozic rocks.The source material for the Sinian to Paleozoic sedimentary rocks was controlled by different basement rocks.Sinian and Paleozoic sedimentary rocks from the north of the Jiangnan deep fault zone contain old rocks from the northern margin of the Yangtze block,while that from the south of the deep fault contain only material from the Mid Proterozoic basement in the southern margin of the Yangtze block.Jinningian evolution of both southern and northern margins of the Yangtze block might be closely related to the Rodinia super continent although relevant work lacks.Triassic deep subduction of the continent,continent continent collision and ultrahigh pressure metamorphism in the Dabie orogenic belt has become one of focuses of the international interest.Extensive magmatism and related mineralization occurred in the region 120 to 140 Ma ago.Late Mesozoic intermediate and acidic igneous rocks were formed by mixing of the crustal and mantle derived materials.The sub continental mantle along the Yangtze River shows enriched geochemical characteristics and the isotopic characters of the Mesozoic mantle of the region can be modeled by mixing between DMM component representing asthenospheric mantle and EM II representing the Yangtze type lithospheric mantle.From the Later Mesozoic to Quaternary,the isotopic compositions of mafic intrusive rocks and basalts show a progressive change toward more depleted mantle characteristics.
Download(CAJ format) Download(PDF format)
CAJViewer7.0 supports all the CNKI file formats; AdobeReader only supports the PDF format.
©CNKI All Rights Reserved