本文選題：阿拉善 + 韌性剪切帶��； 參考：《中國地質(zhì)大學(xué)(北京)》2017年碩士論文

【摘要】：巴音諾爾公地區(qū)NNE向韌性剪切帶位于內(nèi)蒙古阿拉善左旗巴音諾爾公南部,長約17km,寬約5km。在剪切帶的北部及中部糜棱面理傾向南東,傾角55°~85°,南部糜棱面理傾向南西,傾角70°~87°。糜棱巖帶自西向東劃分為糜棱巖化帶—糜棱巖帶—初糜棱巖帶(弱—強(qiáng)—弱)。帶內(nèi)發(fā)育的糜棱面理、拉伸線理、S C構(gòu)造、旋轉(zhuǎn)殘斑、書斜構(gòu)造、“云母魚”等宏觀及微觀構(gòu)造,平面上呈現(xiàn)左行剪切特征,剖面上呈現(xiàn)上盤(東盤)下降的運(yùn)動方式。利用礦物溫度計、EBSD石英C軸組構(gòu)綜合分析該韌性剪切帶的溫度在250~530℃區(qū)間內(nèi),存在兩個溫度區(qū)間即500°~530°(早期剪切階段)與250°~300°(晚期剪切階段),圍壓為200~400MPa。推斷剪切帶形成于8~16Km的深度范圍內(nèi)。差應(yīng)力值為:44.31~97.94MPa,應(yīng)變速率為10-14 s-1(300℃)和10-11 s-1(500℃)。糜棱巖帶的渦度值W_k=0.94,顯示剪切帶晚期階段主要為簡單剪切。使用S C面理法計算出的剪應(yīng)變值為0.7。按變形帶寬度平均值2000m計算,同時不考慮該韌性剪切帶的體積變化,糜棱巖帶的剪切位移量為1400m。韌性剪切帶的剪切運(yùn)動分為兩個階段,結(jié)合U Pb鋯石LA ICP MS法年齡測試資料,形成結(jié)果為:中高溫變形階段為三疊紀(jì)的早期,低溫變形階段為三疊紀(jì)早期到白堊紀(jì)早期。
[Abstract]:The NNE ductile shear zone is located in the southern part of Bayinnuogong, Alashan left Banner, Inner Mongolia, with a length of about 17 km and a width of about 5 km. In the northern and middle part of the shear zone, the surface of the mylonian tends to the south east, with a dip angle of 55 擄/ 85 擄, and the southern surface of the ridge tends to the south west with a dip angle of 70 擄/ 87 擄. The mylonite belt is divided from west to east into mylonium-mylonite zone and primary mylonite zone (weak-strong and weak-mylonite zone). The microcosmic and macroscopic structures, such as metagonal texture, extensional lineal tectonics, rotational speckles, diagonal structures, "mica fish" and so on, are developed in the belt. They show left-row shear characteristics on the plane and downward motion on the upper (eastern) face on the section. The temperature of the ductile shear zone in the temperature range of 250 鈩，

本文編號：1805117