【作者】 王瑜；

【导师】 任纪舜；

【作者基本信息】 中国地质科学院 ， 构造地质学， 1994， 博士

【摘要】 中国东部内蒙—燕山地区是一个以太古代—早古生代的演化为背景，晚古生代晚期—中生代时形成的复合型造山带。造山作用开始前为西伯利亚—中朝大陆间活动大陆边缘—活动大陆边缘的陆—弧—弧—陆碰撞的板块演化环境。造山作用始于P₁²—P₂¹。不同时期的构造演化伴随着不同的沉积盆地类型，如残余弧后盆地、磨拉石盆地、上叠式盆地及断陷盆地等。P₂—T₂时形成EW向展布的强烈的韧性剪切作用及鞘褶皱、“A”型褶皱、滑脱型平卧、倒转褶皱等。内蒙地区的韧性剪切带形成于246.3Ma—197.4±3.8Ma，燕山地区为256.10±0.56Ma—202.0Ma±，并且内蒙、燕山地区自北而南构造变形具形成时间、运动方向的一致性。T₃—J₁时形成上叠式的含煤盆地。于J₁—J₂时区内发育大规模的自苏左旗—锡林浩特—白音宝力格一线分别向南北两侧逆冲的浅层次脆性冲断作用。自此线由北而南变形收缩量从65％降为20％，直至变形消失。构造几何形态表现为韧性剪切一褶皱作用（褶皱推覆）叠加有浅层次逆冲一推覆作用。J₂始（161Ma±），内蒙、燕山地区，由EW向古欧亚构造域转为NE向展布的西太平洋构造域，并以161—140Ma时逆时针45°角的韧性剪切旋转、褶皱和逆冲推覆表现出来。区内不同时间形成、不同类型的糜棱岩的岩石化学成分的变化表现出一定的规律性，并且在递进变形中成分变化不大。韧性剪切带形成环境不同：内蒙碰撞区为P=1.5—2.5kbar、T=320—400℃、高应变环境；燕山、内蒙南缘为P=4.5—6.5k bar、T=480—620℃、低应变的环境。由碰撞带向稳定陆块区的应力、能量传递是在岩浆热作用形成的韧性状态下，由晶内位错攀爬、流体参与、片状矿物提供滑移介质、长石石英旋转碎斑提供支撑空间界面而向着应力降低的方向传递。区内不同类型的岩浆侵入作用如幔源型、壳内重熔型等与构造变形的形成演化相对应，并且中上地壳层次的构造变形的应力作用与深部上地幔的动力呈反相关关系。更多还原

【Abstract】 Inner Mongolia—Yanshan area orogenic belt in Eastern China, which with the tectonic evolutional background from the Archean to the early Paleozoic, was formed as a compound orogenic belt during the late Late—Paleozoic—Mesozoic. Piror to the orogeny, it was a plate subduction—collision evolutional processes of continent—island arc—island arc—continent be- tween Siberian and Sino—Korean active continental margins. The orogenic process started . from P₁²—P₂¹ In different time, the tectonic evolution was accompanied with various sedimen- tary basins such as the remnant island arc basin, the molasse basin, the up—piled basin and fault basins etc. When P₂—T₂, in this region, the strong and wide ductile shear extended to EW direction and guard—like fold, "A"type fold, sliding fold, reverse fold and so on devel- oped. Within the Inner Mongolian orogenic belt, the ductile shear zones were built up at 246. 3 Ma—197. 4±3.8Ma （ K—Ar isostopic age）. Also, in Yanshan area, the formation of the ductile shear zones grew during 256. 10±0. 56—202. 0Ma±(³⁹Ar/⁴⁰Ar ). In T₃—J₁, the piled—up coal—bearing basins in Inner Mongolia and other regions took shape. At J₁—J₂, the brittle thrust systems developed from Sunite—Xilinhaote—Baiyinbaolige line verging toward south and north respectively. Also, from the north to the South, the compressive shortenings are descent from 65% to 20%, until non—deformation. And, from the north to the south, in Inner Mongolia area, the evolutional time and the vergences of the tectonic deformation are concordant with Yanshan region. The tectonic framework is ductile shear—sliding fold defor- mation （ fold nappe tectonics ） pried up the upper brittle thrust nappe tectonics.From J₂ on （161Ma±）, in Inner Mongolia—Yanshan area, the geodynamics changed into the Circum Pacific territory appeared as the reverse clockwise ductile shear rotation, fold and thrust nappe as well as.The regularity of the petrochemical composition changes during the process of the my- lonites formation can be found that the components of the mylonite and their protoliths are in- crease or decrease or a little change at different time, for various types of mylonites, as well as in progressively deformational process. The ductile shear zones were built up on the different P—T—τenvironment: within the Inner Mongolia coUisional zone, P=1.5—2.5kbar, T=320°—400℃, highτ; In Yanshan and the south of Inner Mongolia tectonic belt, P=4.5—6. 5kbar, T=480°—620°, lowτ.With the ductile state formed by the thermal—magmatism, the stress and the energy to- ward the stress descent direction passed on from the plate collision belt to the relatively stable continental block by the dislocation glide （ climb ） within the crystalline, the fluid action, slid- ing media supported by schist materials, the sliding space by feldspar, quartz ere rotational mortar texture.The various kinds of intensive magmatic intrusion such as the mantle—derived magma- tism, the crust anatexis ere related and compared with the formation and the tectonic evolution in different time. As well as, the stress of the deformation on the upper—middle crust is con- troverse relationship to the upper mantle evolutional geodynamics.更多还原