论文部分内容阅读
应用传统的岩石学温度压力计,对大别造山带高压-超高压变质岩形成的温压条件进行了计算.通过温压结构、岩石组合以及同位素年代学分析,提出该造山带由6个岩石构造单元构成.除(1)北淮阳变质带变质温压条件较低外,温度压力自北向南逐渐降低;(2)北大别变质带(900±50℃,4.5±0.5 GPa)→(3)中大别-I带(728±58℃,3.87±0.36 GPa)→(4)中大别-II带(613±48℃,3.09±0.20 GPa)→(5)南大别变质带(521±50℃,2.40±0.24 GPa)→(6)宿松杂岩带(507±48℃,1.0±0.2 GPa),峰期变质年龄也由北向南逐渐变老,从218-226 Ma→226 Ma→230 Ma→235 Ma→251 Ma.且在中大别-I,II带发现大量与南大别带属性相似的物质,确证了宿松杂岩仅经历了绿帘角闪岩相变质,缺乏高压蓝片岩相带的记录.结合构造几何学和运动学研究表明,这些单元均以构造岩片型式叠置产出,具有穿时性,彼此之间被断裂所分割,这暗示大陆地壳俯冲过程中于不同深度发生拆离,结果大别造山带是由多板片的俯冲/折返而成.
The temperature and pressure conditions for the formation of the UHP-UHPM metamorphic rocks in the Dabie orogenic belt are calculated by using the traditional petrophysical pressure manometer.According to the temperature-pressure structure, the rock assemblage and the isotopic chronological analysis, it is proposed that the orogenic belt consists of 6 rocks (2) The temperature ranged from 900 ± 50 ℃ to 4.5 ± 0.5 GPa → (3) in the North Dabieite metamorphic belt (3) (613 ± 48 ℃, 3.09 ± 0.20 GPa) → (5) Dabie-I zone (728 ± 58 ℃, 3.87 ± 0.36 GPa) → (4) Middle Dabie-II zone 50 ℃, 2.40 ± 0.24 GPa) → (6) Susong complex zone (507 ± 48 ℃, 1.0 ± 0.2 GPa), and the peak metamorphic age also gradually aged from north to south from 218-226 Ma → 226 Ma → 230 Ma → 235 Ma → 251 Ma, and a large number of similar materials were found in the Middle Dabies-I and II belts with similar properties to the Southern Dabie belt, confirming that the Susong complex experienced only exponential metamorphism of chlorite and absence of high-pressure blue The study of tectonic geometry and kinematics shows that these units are all superimposed by tectonic slices and are of permutation and divided by faults, which implies that the continental crust subduction process In different depths of the demolition occurred, the results of the Dabie orogenic belt is a multi-plate subduction / reentry.