Decipher the driving force in continental drift from new insights about the South Atlantic breakup process

doi:10.13745/j.esf.sf.2021.12.27

Abstract

Abstract:

It has been widely recognized that the separation of the African and South American continents is caused by the South Atlantic breakup. The South Atlantic region is highly relevant to the development of the continental drift hypothesis. The driving force behind continental drift, however, has been in debate ever since the hypothesis was proposed. Therefore, quantitative analysis of the forces driving plate movement in the process of Atlantic breakup is particularly important. Here, we analyzed two deep seismic reflection survey profiles located on either side of the South Atlantic, in passive continental margin basins, and estimated the Moho dip angle of the African continent on the basis of tectonic geological interpretation. We then calculated the magnitude of crustal gravitational slip shear force along the Moho to explain the dynamic mechanism of African continent movement in the process of Atlantic breakup. We demonstrated that the African continental crust can produce a strong gravitational slip force on the inclined interface formed by mantle upwelling, and the shear force is greater in the south than in the middle part of the crust. According to our analysis, the continental crust can drift continuously by continuous hot mantle upwelling and gravitational slide. This model can reasonably explain the genetic mechanism for the many linear continental fragments in the Atlantic Ocean, and it can also provide an internal reason for why the South Atlantic today is wider in the south than it is in the middle. Based on this model we reconstructed the tectonic evolutionary history of the South Atlantic breakup process. This research established a new dynamic model of plate motion and provided more accurate constraint on understanding the driving force behind plate movement.

Key words: Atlantic breakup, African continental crust, South American continental crust, gravitational slip, continental drift

CLC Number:

P542
P541

LIANG Guanghe, YANG Weiran. Decipher the driving force in continental drift from new insights about the South Atlantic breakup process[J]. Earth Science Frontiers, 2022, 29(1): 316-327.

Figures/Tables 9

Fig.1 Geomorphic elevation and distribution of main seamounts and volcanoes in the South Atlantic region

Fig.2 Distribution of passive continental marginal basins on the two sides of the South Atlantic and the profile locations in the study area. Modified after [19].

Fig.3 Two structural sections of the passive basins on two sides of the South Atlantic and related Moho dip angles (modified after [19]). (a) Profile A-A' in the middle South Atlantic. (b) Profile B-B' in the southern South Atlantic. Areas inside the purple box were used in calculating the Moho dip angles.

Fig.4 Model of gravitational sliding on inclined Moho surface and calculation of shear stress

Fig.5 Schematic diagram of the South Atlantic breakup and continental drift processes. (a) Initial cracking stage. (b) Drift process. (c) Current state.

Fig.6 Schematic diagram of the new continent drift model, demonstrating the process is driven by mantle upwelling and gravitational slip

Fig.7 Schematic diagram illustrating the tectonic evolutionary process of the Atlantic breakup

Fig.8 Simplified diagram of two passive continental margin structural models (adapted from [22]) and the slip driving force. (a) Model of passive continent with volcanic-rifted margin. (b) Model of passive continent with magma-poor margin. (c) Simplified geological interpretation of a. (d) Simplified geological interpretation of b.

Fig.9 Comparison of differential stress characteristics between continental (A) and oceanic (B) lithosphere. Modified after [32,33,34].

References 44

[1]	WEGENER A. The origins of the continents[J]. Journal of Geodynamics, 2001, 32:31-63.
[2]	陈凌, 王旭, 梁晓峰, 等. 俯冲构造vs.地幔柱构造:板块运动驱动力探讨[J]. 中国科学: 地球科学, 2020, 50(4):501-514. DOI: 10.1360/SSTe-2019-0106. DOI
[3]	杨经绥, 连东洋, 吴魏伟, 等. 俯冲物质深地幔循环: 地球动力学研究的一个新方向[J]. 地质学报, 2021, 95(1):42-63.
[4]	WOLFGANG F, MARTIN M, BLAKEY R. Plate tectonics[M]. Berlin, Heidelberg: Springer, 2011.
[5]	HOERNLE K, ROHDE J, HAUFF F, et al. How and when plume zonation appeared during the 132 Myr evolution of the Tristan Hotspot?[J]. Nature Communications, 2015, 6:7799. https://doi.org/10.1038/ncomms8799 DOI URL
[6]	BOUYSSE P. Geological map of the world. Scale: 1∶50000000[M]. 3rd ed. Paris: CGMW/CCGM, 2009.
[7]	YONO T, CHOI D R, GAVRILOV A A, et al. Ancient and continental rocks in the Atlantic Ocean[J]. New Concepts in Global Tectonics Newsletter, 2009, 53:4-37.
[8]	SKOLOTNEV S G, BELTNEV V E, LEPEKHINA E N, et al. Younger and older zircons from rocks of the oceanic lithosphere in the central Atlantic and their geotectonic implications[J]. Geotectonics, 2010, 44(6):462-492. DOI URL
[9]	CLASS C, ROEX A L. South Atlantic DUPAL anomaly: dynamic and compositional evidence against a recent shallow origin[J]. Earth and Planetary Science Letters, 2011, 305(1/2):92-102. DOI URL
[10]	EWINGJ I, LUDWIG W J, EWING M, et al. Structure of the Scotia Sea and Falkland Plateau[J]. Journal of Geophysical Research Atmospheres, 1971, 76(29):7118-7137. DOI URL
[11]	DERUELLE B, NGOUNOUNO I, DEMAIFFE D. The ‘Cameroon Hot Line’ (CHL): a unique example of active alkaline intraplate structure in both oceanic and continental lithospheres[J]. Comptes Rendus: Géoscience, 2007, 339(9):589-600.
[12]	GANNOUN A, BURTON K W, BARFOD D N, et al. Resolving mantle and magmatic processes in basalts from the Cameroon volcanic line using the Re-Os isotope system[J]. Lithos, 2015, 224/225:1-12. DOI URL
[13]	VENTURA R S, GANADE C E, LACASSE C M, et al. Dating Gondwanan continental crust at the Rio Grande Rise, South Atlantic[J]. Terra Nova, 2019, 31:424-429. DOI URL
[14]	任纪舜, 徐芹芹, 赵磊, 等. 寻找消失的大陆[J]. 地质论评, 2015, 61(5):969-989.
[15]	ESCRIG S, SCHIANO P, SCHILLING J G, et al. Rhenium-osmium isotope systematics in MORB from the Southern Mid-Atlantic Ridge (40 degrees-50 degrees S)[J]. Earth and Planetary Science Letters, 2005, 235:528-548. DOI URL
[16]	ESCRIG S, CAPMAS F, DUPRE B, et al. Osmium isotopic constraints on the nature of the DUPAL anomaly from Indian mid-ocean-ridge basalts[J]. Nature, 2004, 431:59-63. DOI URL
[17]	PEATE D W, HAWKESWORTH C J, MANTOVANI M S M, et al. Petrogenesis and stratigraphy of the High-Ti/Y Urubici magma type in the Paraná Flood Basalt Province and implications for the nature of the ‘Dupal’-type mantle in the South Atlantic Region[J]. Journal of Petrology, 1999, 40:451-473. DOI URL
[18]	FODOR R V, HANAN B B. Geochemical evidence for the Trindade hotspot trace: Columbia seamount ankaramite[J]. Lithos, 2000, 51(4):293-304. DOI URL
[19]	章雨, 李江海, 杨梦莲, 等. 南大西洋两岸被动大陆边缘构造分段性特征及其成因探讨[J]. 中国石油勘探, 2019, 24(6):799-806.
[20]	BRUNE S, HEINE C, CLIFT P D, et al. Rifted margin architecture and crustal rheology: reviewing Iberia-Newfoundland, Central South Atlantic, and South China Sea[J]. Marine & Petroleum Geology, 2017, 79:257-281.
[21]	BLAICH O A, INGE F J, FILIPPOS T. Crustal breakup and continent-ocean transition at South Atlantic conjugate margins[J]. Journal of Geophysical Research: Solid Earth, 2011, 116:B01402.
[22]	FRANKE D. Rifting, lithosphere breakup and volcanism: comparison of magma-poor and volcanic rifted margins[J]. Marine and Petroleum Geology, 2013, 43:63-87. DOI URL
[23]	CLERC C, RINGENBACH J C, JOLIVET L, et al. Rifted margins: ductile deformation, boudinage, continentward-dipping normal faults and the role of the weak lower crust[J]. Gondwana Research, 2018, 53:20-40. DOI URL
[24]	BOTT M H P. Ridge push and associated plate interior stress in normal and hot spot regions[J]. Tectonophysics, 1991, 200:17-32. DOI URL
[25]	毛小平, 陆旭凌弘, 王晓明, 等. 周向应力在地壳运动中的作用[J]. 地学前缘, 2020, 27(1):221-233.
[26]	HUBBERT M K, RUBEY W W. Role of fluid pressure in mechanics of overthrust faulting[J]. Geological Society of America Bulletin, 1959, 70:115-166. DOI URL
[27]	HALES A L. Gravitational sliding and continental drift[J]. Earth and Planetary Science Letters, 1969, 6:31-34. DOI URL
[28]	JACOBY W R. Instability in the upper mantle and global plate movements[J]. Journal of Geophysical Research, 1970, 75:5671-5680. DOI URL
[29]	SUZANNE E, BEGLINGE R, HARRY D, et al. Relating petroleum system and play development to basin evolution: West African South Atlantic basins[J]. Marine and Petroleum Geology, 2012, 30:1-25. DOI URL
[30]	朱伟林, 崔旱云, 吴培康, 等. 被动大陆边缘盆地油气勘探新进展与展望[J]. 石油学报, 2017, 38(10):1099-1109.
[31]	王殿举, 李江海, 李一赫. 下地壳流变学性质对南大西洋两岸盆地结构不对称性的控制[J]. 地学前缘, 2020, 27(3):254-261.
[32]	KRONENBERG A, BRANDON M T, FLETCHER R, et al. Beyond plate tectonics: rheology and orogenesis of the continents[M]// New departures in structural geology and tectonics. San Francisco: Stanford University Press, 2003.
[33]	JACKSON J. Strength of the continental lithosphere: time to abandon the jelly sandwich?[J]. GSA Today, 2002, 12:4-9.
[34]	KOHLSTEDT D L, EVANS B, MACKWELL S J. Strength of the lithosphere: constraints imposed by laboratory experiments[J]. Journal of Geophysical Research: Solid Earth, 1995, 100(B9):17587-17602.
[35]	FRANKEL H R. The continental drift controversy[M]. New York: Cambridge University Press, 2012.
[36]	PAVLENKOVA N I, PAVLENKOVA G A. The upper mantle structure of the Northern Eurasia from seismic profiling with nuclear explosions[J]. NCGT Journal, 2017, 5(1):6-26.
[37]	GUNGY C, PANNING M, ROMANOWICZ B. Global anisotropy and the thickness of continents[J]. Nature, 2003, 422(6933):707-711. DOI URL
[38]	SHAPIRO N M, RICZWOLLER M H, MARESCHAL J C, et al. Lithospheric structure of the Canadian Shield inferred from inversion of surface-wave dispersion with thermodynamic a priori constraints[J]. Geological Society, London, Special Publications, 2004, 239(1):175-194. DOI URL
[39]	任纪舜, 牛宝贵, 赵磊, 等. 地球系统多圈层构造观的基本内涵[J]. 地质力学学报, 2019, 25(5):607-612.
[40]	WILSON J T. Static or mobile Earth: the current scientific revolution[J]. Tectonophysics, 1969, 7(5) : 600-601. DOI URL
[41]	马杏垣. 中国岩石圈动力学图集[M]. 北京: 中国地图出版社, 1989.
[42]	杨巍然, 郭铁鹰, 路元良, 等. 中国大地构造演化中的“开”与“合”[J]. 地球科学: 中国地质大学学报, 1984, 9(3):39-53.
[43]	杨巍然, 姜春发, 张抗, 等. 开合旋构造体系及其形成机制探讨: 兼论板块构造的动力学机制[J]. 地学前缘, 2019, 26(1):337-355.
[44]	杨巍然, 姜春发, 张抗, 等. 运用开合旋构造观探究地球内部是如何运行的[J]. 地学前缘, 2020, 27(1):204-210.