Could Continents Really Drift?
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摘要: 魏根纳的大陆漂移设想起源于“对大西洋两岸吻合的直觉印象”.这种“吻合”是指大西洋两侧南美洲和非洲海岸线的吻合.然而，近数十年的海底地球物理和地质调查确已发现，大西洋及其两岸大陆的磁异常、地震层析图像、地震探测剖面以及洋中脊岩石中锆石年龄的测定都说明大西洋是大陆裂谷作用裂陷形成的海洋，两侧大陆并没有发生显著的水平位移，而世界各大陆块深达300~400 km大陆根的存在，似乎已基本否定了大陆发生大规模移动的可能.Abstract: Wegener's idea of continental drift stemmed from an intuitive impression of the coincidence of both sides of the Atlantic Ocean. This coincidence is represented by the fit of coastlines of South America and Africa on both sides of the Atlantic. In recent decades, however, the submarine geophysical and geological investigations have discovered that the magnetic anomalies, seismic tomographic images and seismic profiles of the Atlantic Ocean and the continents on its both sides, and the zircon ages of the determined rocks in mid-ocean ridge indicate the formation of the ocean by continental rifting. There is no significant horizontal displacement of the continents on both sides. Furthermore, the existence of continental roots as deep as 300-400 km in the world's continents seem to have basically denied the possibility of large-scale continental drift.
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Key words:
- continental drift /
- the Atlantic Ocean /
- magnetic anomaly /
- seismic tomographic image /
- geophysics
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图 1 根据大陆移动论3个地质时期的世界地图复原图（Wegener，1929）
Fig. 1. Reconstructed maps of the world in three geological periods based on the theory of continental drift (Wegener, 1929)
图 2 全球磁异常图（据Korhonen et al.，2007）
Fig. 2. Magnetic anomaly map of the World (Korhonen et al., 2007)
图 3 大西洋两岸地震层析图像（O’Reilly et al.，2009）
Fig. 3. Seismic tomographic images of both sides of the Atlantic (O'Reilly et al., 2009)
图 4 桑托斯盆地南部的地质剖面（Zalán et al.，2011）
Fig. 4. Geological section of the southern part of the Santos basin (Zalán et al., 2011)
图 5 海底地貌图（Rémur et al.，1980）
Fig. 5. The floor of the oceans (Rémur et al., 1980)
图 6 横穿北欧亚大陆之地震剖面（a）（据Pavlenkova and Pavlenkova，2017）、加拿大地盾岩石圈层厚度（b）（据Shapiro et al.，2004）
WS、Q1、Q2、Q3、C1、C2、C3、C4指示和平核爆炸点位；M代表莫霍面；T代表上、下地幔过渡带的顶部；N1、N2、L和H代表速度恒定的上地幔基本边界
Fig. 6. Seismic profile across northern Eurasian continent (a) (after Pavlenkova and Pavlenkova, 2017) and thickness of Canadian shield lithosphere (b) (after Shapiro et al., 2004)
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[1] Korhonen, J. V., Fairhead, J. D., Hamoudi, M., et al., 2007. Magnetic Anomaly Map of the World (1st edition), scale: 1∶50 000 000. Commission for the Geological Map of the World, Paris. [2] O'Reilly, S. Y., Zhang, M., Griffin, W. L., et al., 2009. Ultradeep Continental Roots and Their Oceanic Remnants: a Solution to the Geochemical "Mantle Reservoir" Problem? Lithos, 112: 1043-1054. https://doi.org/10.1016/j.lithos.2009.04.028 [3] Pavlenkova, G. A., Pavlenkova, N. I., 2017. The Upper Mantle Structure of the Northern Eurasia from the Seismic Profiling with Nuclear Explosions. New Concepts in Global Tectonics Journal, 5(1): 6-26. [4] Ren, J. S., Jiang, C. F., Zhang, Z. K., et al., 1980. Tectonic Evolution of China. Science Press, Beijing (in Chinese). [5] Ren, J. S., Xu, Q. Q., Zhao, L., et al., 2015. Looking for Submerged Landmasses. Geological Review, 61(5): 969-989 (in Chinese with English abstract). [6] Rémur, T. D., Heezen, B. C., Tharp, M., 1980. The Floor of the Oceans. Marie Tharp. [7] Shapiro, N. M., Ritzwoller, M. H., Mareschal, J. C., et al., 2004. Lithospheric Structure of the Canadian Shield Inferred from Inversion of Surface-Wave Dispersion with Thermodynamic a Priori Constraints. Geological Society, London, Special Publications, 239(1): 175-194. https://doi.org/10.1144/gsl.sp.2004.239.01.12 [8] Skolotnev, S. G., Bel'tenev, V. E., Lepekhina, E. N., et al., 2010. Younger and Older Zircons from Rocks of the Oceanic Lithosphere in the Central Atlantic and Their Geotectonic Implications. Geotectonics, 44(6): 462-492. https://doi.org/10.1134/s0016852110060038 [9] Wegener, A., 1929. The Formation of Continents and Oceans (Translated by Zhang, Y. Y., 1986). The Commercial Press, Beijing (in Chinese). [10] Zalán, P. V., Severino, M. G., Rigoti, C. A., et al., 2011. An Entirely New 3-D View of the Crustal and Mantle Structure of a South Atlantic Passive Margin–Santos, Campos and Espírito Santo Basins, Brazil. AAPG Annual Conference and Exhibition, Houston. [11] 任纪舜, 姜春发, 张正坤, 等, 1980. 中国大地构造及其演化. 北京: 科学出版社. [12] 任纪舜, 徐芹芹, 赵磊, 等, 2015. 寻找消失的大陆. 地质论评, 61(5): 969-989. https://www.cnki.com.cn/Article/CJFDTOTAL-DZLP201505001.htm [13] Wegener, A., 1929. 大陆和海洋的形成(张翼翼译, 1986). 北京: 商务印书馆. -
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