شبیه‌سازی عدی تاثیر رئولوژی بر کشش در ورق قاره‌ای سوار در فرورانش اقیانوسی: با نگاه به فرورانش نئوتتیس در ائوسن

نوع مقاله : مقاله پژوهشی‌

نویسندگان

1 استادیار، دانشکده مهندسی، گروه نقشه‌برداری، دانشگاه زنجان، زنجان، ایران

2 دانشیار، دانشکده علوم زمین، دانشگاه تحصیلات تکمیلی در علوم پایه، زنجان، ایران

3 استاد، دانشکده علوم زمین، دانشگاه سوربن، پاریس، فرانسه

چکیده

هدف این تحقیق شبیه‌سازی تحولات تنش و تغییرشکل ورق قاره‌ای در فرایند فرورانش است. مفهوم اصلی که به آن پرداخته شده این است که پسروی درازگودال در حین فرایند فرورانش می‌تواند به ایجاد رژیم تنش کششی در ورق قاره‌ای سوار، نازک‌‌شدگی آن و تکتونیک کششی در پوسته قاره‌ای منجر شود. ورق ایران در ائوسن کشش توزیع یافته‌ای را تجربه کرده بوده است. یکی از نظریه‌های ناظر بر این رویداد، پسروی اسلب نئوتتیس در آن دوران را مسبب رژیم تنش کششی می‌داند. با کمک شبیه‌سازی‌های عددی برای حل معادلات بقاء حاکم بر جریان و دگرشکلی در پوسته و گوشته بالایی، نقش رئولوژی، ضخامت و سن ورق قاره‌ای در این تحولات مورد مطالعه قرار گرفته است. نتایج نشان می‌دهند که پسروی درازگودال در بازه‌ای بزرگ از پارامترهای فیزیکی شبیه‌سازی‌ها می‌تواند روی دهد. پسروی دراز گودال می‌تواند در یک بازه زمانی 7 تا 12 میلیون‌ساله منجر به رژیم تکتونیکی کششی متمرکز در نزدیکی لبه ورق قاره‌ای شود. برای یک ورق لیتوسفری با رئولوژی قوی این رژیم تکتونیکی به نازک‌شدگی ناچیز و عوارض زمین‌شناسی کوچک‌مقیاس ختم می‌شود. در مقابل با کاهش‌یافتن استحکام رئولوژیکی ورق قاره‌ای (و همچنین با کاهش ضخامت آن) دگرشکلی‌های شدیدتر و بزرگ‌مقیاس‌تری روی می‌دهد که برخی از آنها می‌توانند از نظر شدت و مقیاس زمانی رویداد، قابل مقایسه و تطبیق با آن چه در ائوسن در ایران رخ داده، باشد.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Investigation of the effect of rheology on the upper plate deformation in subduction systems via numerical simulation: Insight into the Eocene Neothetys subduction in Iran

نویسندگان [English]

  • Reza Dousti 1
  • Farhad Sobouti 2
  • Laetitia Le Pourhiet 3
  • Phillipe Agrad 3
1 Assistant Professor, Department of Geodesy and Geomatics,University of Zanjan, Zanjan, Iran
2 Associate Professor, Department of Earth Sciences, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan, Iran
3 Professor, ISTeParis, Sorbonne Université, Paris, France
چکیده [English]

The aim of this study is to simulate stress variations and deformation of the continental plate in the subduction process. The main concept considered is that trench retreat during the subduction process can lead to the creation of an extensional stress regime in the overriding continental plate, and subsequent extension tectonics, and the thinning of the continental crust. The Iranian plate experienced distributed extension in the Eocene. One of the scenarios regarding this event considers the roll-back of the Neo-Tethys slab at that time as the cause of the extensional stress regime. Through numerical simulations to solve the conservation equations governing the flow and deformation in the crust and mantle, the role of rheology, thickness and age of the continental plate in the above-mentioned developments have been investigated. The results show that trench retreat can occur for a large range of physical parameters. Prolonged trench retreat can lead to a localized extensional tectonic regime near the edge of the continental plate above the subduction zone, 7 to 12 million years after the initiation of subduction. For a lithosphere with strong rheology, this tectonic regime results in negligible thinning, too small to be observable in the geological record. In contrast, for weaker continental plate, as well as a thin lithosphere, a wide-range of extensional deformations can occur, some of them comparable in terms of amplitude and time-scale with the events of the Eocene in central Iran.

کلیدواژه‌ها [English]

  • Numerical modeling
  • subduction
  • rheology
  • continental lithosphere
  • extensional deformation
  • trench retreat
Agard, P., Omrani, J., Jolivet, L., Whitechurch, H., Vrielynck, B., Spakman, W., Monié, P., Meyer, B. and Wortel, R., 2011, Zagros orogeny: a subduction-dominated process. Geological Magazine, 148, 692-725.
 Alsaif, M., Garel, F., Gueydan, F. and Davies, R., 2020, Upper plate deformation and trench retreat modulated by subduction-driven shallow asthenospheric flows. Earth and Planetary Science Letters, 532, https://doi.org/10.1016/j.epsl.2019.116013.
Arrial, P. A., Billen, M. I., 2013, Influence of geometry and eclogitization on oceanic plateau subduction. Earth and Planetary Science Letters, 363, 34–43.
Caristan, Y. D., 1980, High temperature mechanical behavior of Maryland diabase, Doctoral Dissertation, Mass. Inst. of Technol. Cambridge, Mass.
Cerpa, N. G., Guillaume, B. and Martinod, J., 2018, The interplay between overriding plate kinematics, slab dip and tectonics. Geophysical Journal International, 215, 1789–1802.
Connolly, J. A. D., 2005, Computation of phase equilibria by linear programming: A tool for geodynamic modeling and its application to subduction zone decarbonation. Earth and Planetary Science Letters, 236, 524–541.
Conrad, C. P. and Hager, B. H., 1999, Effects of plate bending and fault strength at subduction zones on plate dynamics. Journal of Geophysical Research, Solid Earth, 104, 17551–17571.
De Capitani, C., 1994, Gleichgewichts-Phasendiagramme: Theorie und Software. Beihefte zum Eur. J. Mineral., 72, 48.
Ficini, E., Dal Zilio, L., Doglioni, C. and Gerya, T. V., 2017, Horizontal mantle flow controls subduction dynamics. Scientific Reports,7, 1–7.
Francois, T., Burov, E., Agard, P. and Meyer, B., 2014, Buildup of a dynamically supported orogenic plateau: Numerical modeling of the Zagros/Central Iran case study. Geochemistry Geophysics Geosystems, 15, 2632–2654.
Goetze, C. and Evans, B., 1979, Stress and temperature in the bending lithosphere as constrained by experimental rock mechanics. Geophysical Journal of Royal Astronomical Society, 59, 463–478.
Hansen, F. D. and Carter, N. L., 1983, Semibrittle creep of dry and wet westerly granite at 1000 MPa. The 24th U.S. Symposium on Rock Mechanics (USRMS), Am. Rock Mech. Assoc., College Station, Tex.
Heuret, A. and Lallemand, S., 2005, Plate motions, slab dynamics and back-arc deformation. Physics of Earth and Planetary Interiors, 149, 31–51.
Holt, A. F., Becker, T. W. and Buffett, B. A., 2015, Trench migration and overriding plate stress in dynamic subduction models. Geophysical Journal International, 201, 172–192.
Husson, L., 2012, Trench migration and upper plate strain over a convecting mantle. Physics of Earth and Planetary Interiors, 212–213, 32–43.
Jolivet, L., Menant. A. Clerc, C., Sternai, P., Bellahsen, N., Leroy, S., Pik, R., Stab, M., Faccenna, C. and Gorni, C., 2018, Extensional crustal tectonics and crust-mantle coupling, a view from the geological record. Earth-Science Reviews, 185, 1187–1209.
Karato, S. and H. Jung., 2003, Effects of pressure on high-temperature dislocation creep in olivine, Philosophical Magazine, 83, 401–414.
Lallemand, S., Heuret, A., Faccenna, C. and Funiciello, F., 2008, Subduction dynamics as revealed by trench migration. Tectonics 27, 1–15.
Le Pourhiet, L., May, D.A., Huille, L., Watremez, L. and Leroy, S., 2017, A genetic link between transform and hyper-extended margins. Earth and Planetary Science Letters, 1–4, 57-70.
Liu, L., Gurnis, M., Seton, M., Saleeby, J., Müller, R. D. and Jackson, J. M., 2010, The role of oceanic plateau subduction in the Laramide orogeny. Nature Geoscience, 3, 353–357.
May, D. A., Brown, J. and Le Pourhiet, L., 2014, pTatin3D: high-performance methods for longterm lithospheric dynamics. Proceeding SC′14 Proceedings of the International Conference for High Performance Computing, Networking, Storage and Analysis: pp. 274–284.
May, D. A., Brown, J., LePourhiet, L., 2015, A scalable, matrix-free multigrid preconditionerfor finite element discretizations of heterogeneous Stokes flow. Computational Methods in Applied Mechanical Engineering, 290, 496–523.
Mouthereau, F., Lacombe, O. and Verges, J., 2012, Building the Zagros collisional orogen: Timing, strain distribution and the dynamics of Arabia/Eurasia plate convergence. Tectonophysics, 532, 27–60.
Nakakuki, T. and Mura, E., 2013, Dynamics of slab rollback and induced back-arc basin formation. Earth and Planetary Science Letters, 361, 287–297.
Patriat, M., Collot, J., Danyushevsky, L., Fabre, M., Meffre, S., Falloon, T., Rouillard, P., Pelletier, B., Roach, M. and Fournier, M., 2015, Propagation of back-arc extension into the arc lithosphere in the southern New Hebrides volcanic arc. Geochemistry Geophysics Geosystems., 16, 3142–3159.
Rabiee, A., Rossetti, F. and Asahara, Y., 2020, Long-lived, Eocene-Miocene stationary magmatism in NW Iran along a transform plate boundary, Gondwana Research, 10.1016/j.gr.2020.03.014.
Ranalli, G., 1995, Rheology of the Earth, Chapman & Hall, London.
Rodríguez-González, J., Negredo, A. M., Billen, M. I., 2012. The role of the overriding plate thermal state on slab dip variability and on the occurrence of flat subduction. Geochemistry Geophysics Geosystems, 13, 1–21.
Royden, L. H., Husson, L., 2009, In: Subduction Zone Geodynamics, pp.35–45.
Shea, W. T., Kronenberg, A. K., 1992, Rheology and deformation mechanisms of an isotropic mica schist. Journal of Geophysical Research, 97, 15,201–15,237.
Torsvik, T. H. and Cocks L. R. M., 2017, Earth History and Palaeogeography. Cambridge University Press, Cambridge
Uyeda, S., Kanamori, H., 1979, Back-arc opening and the mode of subduction. Journal of Geophysical Research, Solid Earth, 84, 1049–1061.
Verdel, C.,Wernicke, B. P.,Ramezani, J.,Hassanzadeh, J., Renne, P. R. and Spell, T. L., 2007, Geology and thermochronology of Tertiary Cordilleran-style metamorphic core complexes in the Saghand region of central Iran. Geological Society of America Bulletin, 119, 961-971.
Verdel, C., Wernicke, B. P., Hassanzadeh, J. and Guest, B., 2011, A Paleogene extensional arc flare-up in Iran. Tectonics, 30, https://doi.org/10.1029/2010TC002809.
Yamato, P., Husson, L., Braun, J., Loiselet, C. and Thieulot, C., 2009, Influence of surrounding plates on 3D subduction dynamics. Geophysical Research Letters, 36, 1–5.