内蒙古温都尔庙地区韧性剪切带的研究
A DUCTILE SHEAR ZONE IN THE WENDUERMIAO AREA, NEI MONGGOL (INNER MONGOLIA)
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摘要: 一、区域地质构造概况温都尔庙地区位于内蒙古古生代地槽区南缘,华北陆台北侧,是古生代中亚—蒙古海洋板块南侧俯冲于华北陆台之下的俯冲消减地带。区内发育的主要地层为早古生代温都尔庙群,东西向延展约50km,南北侧与上石炭统生物灰岩呈断层或不整合接触,宽15~20km(图1)。温都尔庙群为一套典型的优地槽早期的火山—沉积产物。下部桑达来音组是以具枕状构造的基性熔岩,或细碧岩、细碧质凝灰岩形成的绿片岩为主,上夹少量赤铁角斑岩和铁矿层,在细碧角斑岩建造中有发育良好的辉绿岩岩墙群;上部哈尔哈达组为深远海相的放射虫铁硅质岩,主要是条带一条纹状细晶石英岩、铁质碧玉岩和绿泥绢云石英片岩。总厚Abstract: The early Paleozoic plate subduction zone in the Wenduermiao area is composed of a series of E-W-trending high-strain zones, of which the Tulin- kai-Ulan Aobao ductile shear zone is the largest in Scale. Both sides of the She- ar zone are controlled by schistosity-kink boundaries. The strain intensity wi- thin the shear zone increases gradually from both margins towards the center. The greatest value of the strain intensity in the centralpart is 11.34, and ra- pidly and unevenly decreases towards both sou them and northern sides, ranging between 1 and 3. The subduction depth of the plate subduction zone resulted from accumu- lation of the amount of the shear displacements of all the high strain zones, and the results of measurements of the amount of the displacements of five cross-sections in the Tulinkai-Ulan Aobao zone are close, the average value being 5358.9m.