Crustal Velocity Structure beneath the Site of Chinese Continental Scientific Drilling Site
-
摘要: 为了深入研究大别—苏鲁超高压变质带的深部结构及空间展布特征, 进一步揭示该超高压变质形成的动力学过程, 在中国大陆科学钻探场址区进行了广角反射/折射地震测深调查.根据广角反射/折射地震测深的资料研究, 建立了中国大陆科学钻探场址区的地壳纵波速度结构.从纵向上来看, 研究区域的地壳结构可划分为上、中、下3层: 上地壳的速度小于6.2 0km/s, 厚10余km; 中地壳的速度为6.4 0km/s, 厚亦为10km左右; 下地壳的速度为6.6 0km/s.地壳厚度为31km左右, 且其地壳的平均速度为6.30km/s.上地壳中的速度倒转指示了超高压变质体在地壳内部的空间分布, 且超高压变质体在大陆科学钻探场址及其附近的下部呈现为一隆起形态.Abstract: In order to study the deep structure, spatial tectonic characteristics and the dynamic process for the Dabie-Sulu ultral-high metamorphic belt, a wide-angle reflection/refraction seismic survey was conducted in the Chinese Continental Scientific Drilling (CCSD) site. The crustal velocity structure beneath the CCSD site has been established based on wide-angle seismic reflection/refraction data acquired at the site. According to the results, the crust beneath CCSD is composed of three layers: the upper, middle and lower crust, with velocities of < 6.20 km/s, 6.40 km/s, and 6.60 km/s, and a thickness of ~10 km, ~10 km, and ~12 km respectively. The crust thickness is 31 km around with an average velocity of 6.30 km/s. However, the reversed velocity in the upper crust implies an ultrahigh-pressure metamorphic (UHPM) layer (body) with a shape of uplift beneath or near the CCSD site.
-
Key words:
- CCSD /
- deep seismic sounding /
- crustal velocity structure /
- UHPM zone
-
图 1 中国大陆科学钻探场址及其周边地区地质构造略图及地震测线位置
1.超高压变质带; 2.高压变质带; 3.中、新生代沉积; 4.花岗岩; 5.断裂; 6.地震剖面及炮点; WYF.五莲-烟台断裂; JXF.嘉山-响水断裂; TLF.郯城-庐江断裂; XGF.新沂-赣渝断裂
Fig. 1. Tectonic sketch map and seismic profiles in the CCSD site and its adjacent area
图 2 测线Ⅰ上W07炮的P波地震记录截面
综合速度vr为6.00 km/s, 下同
Fig. 2. Seismic record section from shotpoint W07 in Profile Ⅰ
图 6 测线Ⅰ上E10炮的P波合成地震记录截面
Fig. 6. Synthetic seismic record section from shotpoint E10 in Profile Ⅰ
图 7 测线Ⅱ上N13炮的P波资料的模拟结果
a.地震记录及理论计算走时; b.地壳速度模型其射线路径
Fig. 7. Modeling results from shotpoint N13 in Profile Ⅱ
图 8 中国大陆科学钻探场址区的地壳纵波速度结构
Fig. 8. Crustal velocity structure beneath the CCSD site and its adjacent area
-
Cerveny, V., Psencik, I., 1984. SEIS83-numerical modeling of seismic wavefield in 2-D lateraly varying layered structures by the ray method. In: Engldahl, E.R., ed., Documentation of Earthquake Algorithms. Rep. SE-35, World Data Center(A)for Solid Earth Geophysics, Boulder, Colo. : 36 -40. Cheng, Y.Q., 1994. Regional geology in China. Geological Pubilishing House, Beijing(in Chinese). Cong, B.L., Wang, Q.C., Zhai, M.G., 1994. Ultra-high pressure metamorphism: New challenge in solid earth science. Progress in Geophysics, 9(4): 30-38(in Chinese with English abstract). Mooney, W.D., 1989. Seismic methods for determining earthquake source parameters and lithospheric structure. In: Pakiser, L.C., Mooney, W.D., eds., Geophysical framework of the continental United States, Mem. Geol. Soc. Am., 172: 11-34. Ou, X.G., Jin, Z.M., Jin, S.Y., et al., 2003. Thermal conductivity of Donghai UHP eclogite and its significance for studying continental scientific drilling. Earth Science—Journal of China University of Geosciences, 28(2): 129-136(in Chinese with English abstract). Suo, S.T., Zhong, Z.Q., Zhou, H.W., et al., 2003. Massive eclogites and their significance in Dabie UHP metamorphic belt, East-Central China. Earth Science—Journal of China University of Geosciences, 28(2): 111-120(in Chinese with English abstract). Wang, Y.X., 2002. Crustal structure research using wide-angle seismic reflection in Sulu-Dabie ultrahigh pressure metamorphic belts: Ph. D. Thesis. China University of Geosciences, Beijing(in Chinese). Xu, Z.Q., 1987. Etude tectonique et microtectonique de la chaine paleozoique et triasique des Qinlings(Chine). Academie de Montpellier Universite des Sciences et Techniques du Languedoc, 93-107. Yang, W.C., 1997. Crustal structure and development of Sulu UHPM terrane in East-Central China. Episode, 20(2): 100-103. doi: 10.18814/epiiugs/1997/v20i2/006 Yang, W.C., Cheng, Z.Y., 1998. Crustal structure and development of the Dabie UHPM terrane in East-Central China. Continental Dynamics, 3: 86-95. Yang, W.C., Cheng, Z.Y., Chen, G.J., et al., 1999a. Geophysical investigations in northern Sulu UHPM belt, Part Ⅰ: Deep seismic reflection. Chinese Journal of Geophysics, 42 (1): 41-52(in Chinese with English abstract). Yang, W.C., Fang, H., Cheng, Z.Y., et al., 1999b. Geophysical investigation in northern Sulu UHPM belt, Part Ⅱ : Non-seismic methods. Chinese Journal of Geophysics, 42 (4): 508-519(in Chinese with English abstract). Yang, W.C., Hu, Z.Y., Cheng, Z.Y., et al., 1999c. Long profile of geophysical investigation from Tancheng to Lianshui, east-central China. Chinese Journal of Geophysics, 42 (2): 206-216(in Chinese with English abstract). Yang, W.C., Yu, C.Q., 2001. Kinetics and dynamics of development of the Dabie-Sulu UHPM terranes based on geophysical evidences. Chinese Journal of Geophysics, 44(3): 346-359(in Chinese with English abstract). doi: 10.1002/cjg2.149 Yu, Q.F., Guo, Y.Z., Meng, X.H., 2002. Petrophysical parameters at continental scientific drilling site in Subei, China. Chinese Journal of Geophysics, 45(1): 93-100(in Chinese with English abstract). Yu, Q.F., Yao, C.L., Meng, X.H., et al., 2001. Interpretation of gravity and magnetic anomalies obtained at continental scientific drilling site in Subei. Chinese Journal of Geophysics, 44(6): 825-832(in Chinese with English abstract). Zhang, R.Y., Cong, B.L., Liu, Z.G., 1993. Sulu ultra high pressure metamorphic terrane and exploration of its origin. Acta Petrologica Sinica, 9(3): 211-226(in Chinese with English abstract). https://www.sciencedirect.com/science/article/pii/S0040195102003864 Zhang, Y.K., 1997. Donghai, North Jiangsu: One of the best site options for the first continental scientific drilling in China. Jiangsu Geology, 21(3): 129-137(in Chinese with English abstract). 程裕淇, 1994. 中国区域地质概论. 北京: 地质出版社. 丛柏林, 王清晨, 翟明国, 1994. 超高压变质作用: 固体地球科学领域的新挑战. 地球物理学进展, 9(4): 30-38. https://www.cnki.com.cn/Article/CJFDTOTAL-DQWJ404.003.htm 欧新功, 金振民, 金淑燕, 等, 2003. 江苏东海超高压榴辉岩的热导率及对大陆科学钻探研究的意义. 地球科学—中国地质大学学报, 28(2): 129-136. https://www.cnki.com.cn/Article/CJFDTOTAL-DQKX200302002.htm 索书田, 钟增球, 周汉文, 等, 2003. 大别—苏鲁超高压变质带内的块状榴辉岩及其构造意义. 地球科学—中国地质大学学报, 28(2): 111-120. https://www.cnki.com.cn/Article/CJFDTOTAL-DQKX200302000.htm 王有学, 2002. 苏鲁—大别超高压变质带广角地震测深地壳结构研究. 博士论文, 北京: 中国地质大学. 杨文采, 程振炎, 陈国九, 等, 1999a. 苏鲁超高压变质带北部地球物理调查(Ⅰ)—深反射地震. 地球物理学报, 42 (1): 41-52. https://www.cnki.com.cn/Article/CJFDTOTAL-DQWX901.004.htm 杨文采, 胡振远, 程振炎, 等, 1999c. 郯城-涟水综合地球物理剖面. 地球物理学报, 42(2): 206-216. https://www.cnki.com.cn/Article/CJFDTOTAL-DQWX199902008.htm 杨文采, 余长青, 2001. 根据地球物理资料分析大别苏鲁超高压变质带的运动学与动力学. 地球物理学报, 44(3): 346-359. doi: 10.3321/j.issn:0001-5733.2001.03.007 杨文采, 方慧, 程振炎, 等, 1999b. 苏鲁超高压变质带北部地球物理调查(Ⅱ)—非地震方法. 地球物理学报, 42 (4): 508-519. https://www.cnki.com.cn/Article/CJFDTOTAL-DQWX199904009.htm 余钦范, 姚长利, 孟小红, 等, 2001. 苏北大陆科学钻探靶区重磁异常反演解释. 地球物理学报, 44(6): 825-832. doi: 10.3321/j.issn:0001-5733.2001.06.012 余钦范, 郭友钊, 孟小红, 等, 2002. 苏北大陆科学钻探靶区岩石物理性质. 地球物理学报, 45(1): 93-100. doi: 10.3321/j.issn:0001-5733.2002.01.012 张儒媛, 丛柏林, 刘忠光, 1993. 苏鲁超高压变质地体及其成因解释. 岩石学报, 9(3): 211-226. doi: 10.3321/j.issn:1000-0569.1993.03.001 张永康, 1997. 江苏东海—中国大陆科学钻探的最佳选区之一. 江苏地质, 21(3): 129-137. https://www.cnki.com.cn/Article/CJFDTOTAL-JSDZ703.000.htm -
下载:
点击查看大图
图(9)
计量
- 文章访问数: 3867
- HTML全文浏览量: 485
- PDF下载量: 9
- 被引次数: 0
