【摘要】 为了探测苏鲁超高压变质带的岩石圈结构实施了山东日照到滨洲剖面的宽频带地震探测,于2003～2005年使用REFTER130-01型和CMG-6TD型三分量地震仪(频宽50～60s)。以10～25km间距布设了25个台站观测近三年时间,由远震地震层析反演结果得到了华北板块、超高压变质带、扬子板块清晰的P波速度图像。华北板块具有简单的低速体形态,越过郯庐断裂向超高压变质带扩张,并平稳地由郯庐断裂向北延伸直到黄河以北的古城镇。Moho面和岩石圈深度分别为30～35km,75～80km;扬子板块为高速体,界于两者之间的苏鲁超高压变质带地壳的平均速度大于两侧板块,剖面上从日照到五莲-烟台断裂范围内除地壳为高速体外,30～60km深度范围内有一个高速体和一个低速体拼会在一起,构成了超高压变质带岩石圈最突出的构造特征。此高速体应为榴辉橄榄岩等超基性岩组成,它可能属于折返回来又被移动的超高压变质岩组合体,并与华北板块基底直接接触,超高压变质带的下界面深度为60km。下界面平直,可能意味着正在消退的造山带的山根,或是造山带的下一层Moho面?郯庐断裂带地壳出露的共四条带,比较陡的产状向深部延伸,并逐步向南倾,TLF2～TLF4在岩石圈底界处合并。更多还原

【Abstract】 In order to understand the lithosphere structure beneath Sulu UHPM,a broadband seismic survey was conducted during 2003～2005 from Rizhao to Binzhou in Shandong province,deploying 25 stations with a spacing of 10～25km,using REFTER130-01 and CMG-6TD with three-components seismometers(period between 50～60s),and recording seismic data up to almost three years. The P-velocity image from seismic tomography by the acquired data clearly depicts the characteristics of the different tectonic units, including North China terrane,Sulu UHPM,and Yangtze terrane.The North China terrane within the lithosphere shows a low velocity block which extends stably towards north to Gucheng Zhen in the north of yellow river across Tanlu fault,and the depths of Moho and lithosphere of the North China Terrane are 30～35 and 75～80km,respectively.The Yangtze terrane,however,has a high velocity background.The Sulu UHPM locates between North China Terrane and Yangtze terrane,and its average crust velocity is higher than that in both sides.The UHPM is significantly featured by two high velocity blocks between Rizhao and Wulian-Yantai Fault,one within the crust and another at depth of 30～60km,which probably are composed of ultra-mafic rocks,like ecologites,were exhumated and relocated to form the ultra-metamorphic-rock complex.The bottom of the high velocity block at depth of 60km indicates that the depth of the Sulu UHPM is 60 km,and the flat bottom implies an disappearing orogenic root or another Moho discontinuity?Meanwhile,the tomography image also gives a outline of the Tanlu Fault belt,which inclines steeply towards south and vanished at the bottom of the lithosphere.更多还原