Boninitic blueschists record subduction initiation and subsequent accretion of an arc–forearc in the northeast Proto-Tethys Ocean

Subduction of oceanic lithosphere is a diagnostic characteristic of plate tectonics. However, the geodynamic processes from initiation to termination of subduction zones remain enigmatic mainly due to the scarcity of appropriate rock records. We report the first discovery of early Paleozoic boninitic blueschists and associated greenschists from the eastern Proto-Tethyan North Qilian orogenic belt, northeastern Tibet, which have geochemical affinities that are typical of forearc boninites and island arc basalts, respectively. The boninitic protoliths of the blueschists record intra-oceanic subduction initiation at ca. 492–488 Ma in the eastern North Qilian arc/forearc–backarc system, whereas peak blueschist facies metamorphism reflects subsequent subduction of the arc/forearc complex to high pressure at ca. 455 Ma. These relations therefore record the life circle of an intra-oceanic subduction zone within the northeastern Proto-Tethys Ocean. The geodynamic evolution provides an early Paleozoic analogue of the early development of the Izu–Bonin–Mariana arc and its later subduction beneath the extant Japanese arc margin. This finding highlights the important role of subduction of former upper plate island arc/forearcs in reducing the likelihood of preservation of initial subduction-related rock records in ancient orogenic belts.

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The future of Earth's oceans: consequences of subduction initiation in the Atlantic and implications for supercontinent formation

Geological Magazine ◽

10.1017/s0016756816000716 ◽

2016 ◽

Vol 155 (1) ◽

pp. 45-58 ◽

Cited By ~ 15

Author(s):

JOÃO C. DUARTE ◽

WOUTER P. SCHELLART ◽

FILIPE M. ROSAS

Keyword(s):

Atlantic Ocean ◽

Conceptual Model ◽

Subduction Zone ◽

Subduction Zones ◽

Plate Tectonics ◽

Turning Point ◽

Oceanic Lithosphere ◽

Subduction Initiation ◽

The Pacific ◽

The Future

AbstractSubduction initiation is a cornerstone in the edifice of plate tectonics. It marks the turning point of the Earth's Wilson cycles and ultimately the supercycles as well. In this paper, we explore the consequences of subduction zone invasion in the Atlantic Ocean, following recent discoveries at the SW Iberia margin. We discuss a buoyancy argument based on the premise that old oceanic lithosphere is unstable for supporting large basins, implying that it must be removed in subduction zones. As a consequence, we propose a new conceptual model in which both the Pacific and the Atlantic oceans close simultaneously, leading to the termination of the present Earth's supercycle and to the formation of a new supercontinent, which we name Aurica. Our new conceptual model also provides insights into supercontinent formation and destruction (supercycles) proposed for past geological times (e.g. Pangaea, Rodinia, Columbia, Kenorland).

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Mariana-type ophiolites constrain the establishment of modern plate tectonic regime during Gondwana assembly

Nature Communications ◽

10.1038/s41467-021-24422-z ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Jinlong Yao ◽

Peter A. Cawood ◽

Guochun Zhao ◽

Yigui Han ◽

Xiaoping Xia ◽

...

Keyword(s):

Subduction Zones ◽

Oceanic Lithosphere ◽

Surface Erosion ◽

Plate Tectonic ◽

Mountain Ranges ◽

Tectonic Regime ◽

Subduction Initiation ◽

The Earth ◽

Tethys Ocean ◽

Roll Back

AbstractInitiation of Mariana-type oceanic subduction zones requires rheologically strong oceanic lithosphere, which developed through secular cooling of Earth’s mantle. Here, we report a 518 Ma Mariana-type subduction initiation ophiolite from northern Tibet, which, along with compilation of similar ophiolites through Earth history, argues for the establishment of the modern plate tectonic regime by the early Cambrian. The ophiolite was formed during the subduction initiation of the Proto-Tethys Ocean that coincided with slab roll-back along the southern and western Gondwana margins at ca. 530-520 Ma. This global tectonic re-organization and the establishment of modern plate tectonic regime was likely controlled by secular cooling of the Earth, and facilitated by enhanced lubrication of subduction zones by sediments derived from widespread surface erosion of the extensive mountain ranges formed during Gondwana assembly. This time also corresponds to extreme events recorded in climate and surface proxies that herald formation of the contemporary Earth.

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The subduction initiation stage of the Wilson cycle

Geological Society London Special Publications ◽

10.1144/sp470.3 ◽

2018 ◽

Vol 470 (1) ◽

pp. 415-437 ◽

Cited By ~ 17

Author(s):

Robert Hall

Keyword(s):

Subduction Zones ◽

Plate Tectonics ◽

Oceanic Lithosphere ◽

The West ◽

Subduction Initiation ◽

Deep Crust ◽

Close Relationship ◽

Wilson Cycle ◽

Initiation Stage ◽

Time Required

AbstractIn the Wilson cycle, there is a change from an opening to a closing ocean when subduction begins. Subduction initiation is commonly identified as a major problem in plate tectonics and is said to be nowhere observable, yet there are many young subduction zones at the west Pacific margins and in eastern Indonesia. Few studies have considered these examples. Banda subduction developed by the eastwards propagation of the Java trench into an oceanic embayment by tearing along a former ocean–continent boundary. The earlier subducted slab provided the driving force to drag down unsubducted oceanic lithosphere. Although this process may be common, it does not account for young subduction zones near Sulawesi at different stages of development. Subduction began there at the edges of ocean basins, not at former spreading centres or transforms. It initiated at a point where there were major differences in elevation between the ocean floor and the adjacent hot, weak and thickened arc/continental crust. The age of the ocean crust appears to be unimportant. A close relationship with extension is marked by the dramatic elevation of land, the exhumation of deep crust and the spectacular subsidence of basins, raising questions about the time required to move from no subduction to active subduction, and how initiation can be identified in the geological record.

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Forced subduction initiation at passive continental margins: Numerical modeling

10.5194/egusphere-egu2020-1761 ◽

2020 ◽

Author(s):

Xinyi Zhong ◽

Zhong-Hai Li

Keyword(s):

Subduction Zones ◽

Plate Tectonics ◽

Numerical Models ◽

Oceanic Lithosphere ◽

Ocean Basin ◽

Passive Margin ◽

Complex Case ◽

Subduction Initiation ◽

Boundary Force ◽

Time Required

Subduction initiation (SI) induced by the tectonic boundary force may play a significant role in the Wilson cycle. In the previous analog and numerical models, the constant convergent velocity is generally applied, which may lead to large boundary forces for SI. In this study, we begin with testing the simple case of SI at passive margin with constant convergent force. The results indicate that the boundary force required to trigger the SI at passive margin with a thin and young oceanic lithosphere is much lower than that with a thick and old one. It is consistent with the multiple Cenozoic subduction zones in the Southwest Pacific, which are young ocean basin within 40 Ma and compressed by the India-Australia plate. Furthermore, we extended our model to explore a more complex case, forced SI during the collision-induced subduction transference, which is critical for Tethyan evolution. Both collision and SI processes are integrated in the numerical models. The results indicate that the forced convergence, rather than pure free subduction, is required to trigger and sustain the SI in the neighboring passive margin after collision of terrane. In addition, a weak passive margin can significantly promote the occurrence of subduction initiation, by decreasing required boundary force within reasonable range of plate tectonics. However, the lengths of subducted oceanic slab and accreting terrane play secondary roles in the occurrence of SI after collision. Under the favorable conditions of collision-induced subduction transference, the time required for subduction initiation after collision is generally within 10 Myrs, which is consistent with the general geological records of Neo-Tethys. In contrast, both Atlantic passive margin and Indian passive margin are old and stable with absence of subduction initiation in the present, which remains an open question.

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Plume-induced subduction initiation: single- or multi-slab subduction?

10.5194/egusphere-egu2020-7783 ◽

2020 ◽

Author(s):

Marzieh Baes ◽

Stephan Sobolev ◽

Taras Gerya ◽

Sascha Brune

Keyword(s):

Mantle Plume ◽

Subduction Zones ◽

Plate Tectonics ◽

Large Scale ◽

Oceanic Lithosphere ◽

Extension Rate ◽

Subduction Initiation ◽

Lithospheric Extension ◽

Mechanical Models ◽

Mantle Temperature

The formation of new subduction zones is a key component of global plate tectonics. Initiation of subduction following the impingement of a hot buoyant mantle plume is one of the few scenarios that allow breaking the lithosphere and recycling a stagnant lid without requiring any pre-existing weak zones. According to this scenario, upon arrival of a hot and buoyant mantle plume beneath the lithosphere, the lithosphere breaks apart and the hot mantle plume materials flow atop of the broken parts of the lithosphere. This leads to bending of the lithosphere and eventually initiation of subduction. Plume-lithosphere interaction can lead to subduction initiation provided that the plume causes a critical local weakening of the lithospheric material above it, which depends on the plume volume, its buoyancy, and the thickness of the lithosphere. Previous modeling studies showed that plume-lithosphere interaction can result in initiation of multi- or single-slab subduction zones around the newly formed plateau. However, they did not explore the parameters playing key roles in discriminating between the single- and multi-slab subduction scenarios. Here, we investigate factors controlling the number and shape of retreating subducting slabs formed by plume-lithosphere interaction. Using 3d thermo-mechanical models we show that the response of the lithosphere to arrival of a mantle plume beneath it depends on several parameters such as age of oceanic lithosphere, thickness of the crust, large-scale lithospheric extension rate, relative location of plume head and plateau edge and mantle temperature. The numerical experiments reveal that plume-lithosphere interaction in present day Earth can result in three different deformation regimes: (a) multi-slab subduction initiation, (b) single-slab subduction initiation and (c) plateau formation without subduction initiation. On early Earth (in Archean times) plume-lithosphere interaction could result in formation of either multi-slab subduction zones, very efficient in production of new crust, or episodic short-lived circular subduction. Extension eases subduction initiation caused by plume-lithosphere interaction. Plume-induced subduction initiation of old oceanic lithosphere with a plateau with thick crust is only possible if the lithosphere is subjected to extension.

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An analytical model concerning the possible initiation of subduction between the India and Africa plates, caused by the Morondova plume

10.5194/egusphere-egu2020-6050 ◽

2020 ◽

Author(s):

Bernhard Steinberger ◽

Douwe van Hinsbergen

Keyword(s):

Subduction Zones ◽

Plate Tectonics ◽

Eastern Mediterranean ◽

Plate Boundary ◽

Plate Motion ◽

Mantle Flow ◽

Plate Motions ◽

Subduction Initiation ◽

Euler Pole ◽

Geodynamic Processes

Identifying the geodynamic processes that trigger the formation of new subduction zones is key to understand what keeps the plate tectonic cycle going, and how plate tectonics once started. Here we discuss the possibility of plume-induced subduction initiation. Previously, our numerical modeling revealed that mantle upwelling and radial push induced by plume rise may trigger plate motion change, and plate divergence as much as 15-20 My prior to LIP eruption. Here we show that, depending on the geometry of plates, the distribution of cratonic keels and where the plume rises, it may also cause a plate rotation around a pole that is located close to the same plate boundary where the plume head impinges: If that occurs near one end of the plate boundary, an Euler pole of the rotation may form along that plate boundary, with extension on one side, and convergence on the other.&#160; This concept is applied to the India-Africa plate boundary and the Morondova plume, which erupted around 90 Ma, but may have influenced plate motions as early as 105-110 Ma. If there is negligible friction, i.e. there is a pre-existing weak plate boundary, we estimate that the total amount of convergence generated in the northern part of the India-Africa plate boundary can exceed 100 km, which is widely thought to be sufficient to initiate forced, self-sustaining subduction. This may especially occur if the India continental craton acts like an &#8220;anchor&#8221; causing a comparatively southern location of the rotation pole of the India plate. Geology and paleomagnetism-based reconstructions of subduction initiation below ophiolites from Pakistan, through Oman, to the eastern Mediterranean reveal that E-W convergence around 105 Ma caused forced subduction initiation, and we tentatively postulate that this is triggered by Morondova plume head rise. Whether the timing of this convergence is appropriate to match observations on subduction initiation as early as 105 Ma depends on the timing of plume head arrival, which may predate eruption of the earliest volcanics. It also depends on whether a plume head already can exert substantial torque on the plate while it is still rising &#8211; for example, if the plate is coupled to the induced mantle flow by a thick craton.

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Effect of plate motion on plume-induced subduction initiation

10.5194/egusphere-egu21-7763 ◽

2021 ◽

Author(s):

Marzieh Baes ◽

Stephan Sobolev ◽

Taras Gerya ◽

Robert Stern ◽

Sascha Brune

Keyword(s):

Subduction Zone ◽

Late Cretaceous ◽

Subduction Zones ◽

Plate Tectonics ◽

Plate Motion ◽

Cascadia Subduction Zone ◽

Caribbean Plate ◽

Subduction Initiation ◽

Southern Margin ◽

The Caribbean

Subduction zones are key components of plate tectonics and plate tectonics could not begin until the first subduction zone formed. Plume-induced subduction initiation, which has been proposed as triggering the beginning of plate tectonics (Gerya et al., 2015), is one of the few scenarios that can break the lithosphere and recycle a stagnant lid without requiring any pre-existing weak zones. So far, two natural examples of plume-induced subduction initiation have been recognized. The first was found in southern and western margins of the Caribbean Plate (Whattam and Stern 2014). Initiation of the Cascadia subduction zone in Eocene times has been proposed to be the second example of plume-induced subduction initiation (Stern and Dumitru, 2019).The focus of previous studies was to inspect plume-lithosphere interaction either for the case of stationary lithosphere (e.g., Gerya et al., 2015) or for moving lithosphere without considering the effect of lithospheric magmatic weakening above the plume head (e.g., Moore et al., 1998). In present study we investigate the response of moving oceanic lithosphere to the arrival of a rising mantle plume head including the effect of magmatic lithospheric weakening. We used 3D numerical thermo-mechanical modeling. Using I3ELVIS code, which is based on finite difference staggered grid and marker-in-cell with an efficient OpenMP multigrid solver (Gerya, 2010), we show that plate motion may affect the plume-induced subduction initiation only if a moderate size plume head (with a radius of 140 km in our experiments) impinges on a young but subductable lithosphere (with the age of 20 Myr). Outcomes indicate that lithospheric strength and plume buoyancy are key parameters in penetration of the plume and subduction initiation and that plate speed has a minor effect. We propose that eastward motion of the Farallon plate in Late Cretaceous time could play a key role in forming new subduction zones along the western and southern margin of the Caribbean plate.&#160;References:Gerya, T., 2010,&#160;Introduction to Numerical Geodynamic Modelling.. Cambridge University Press.Gerya, T.V., Stern, R.J., Baes, M., Sobolev, S.V. and Whattam, S.A., 2015. Plume-induced subduction initiation triggered Plate Tectonics on Earth. Nature, 527, 221&#8211;225.Moore, W. B., Schubert, G. and Tackley, P., 1998, Three-dimensional simulations of plume-lithosphere interaction at the Hawaiian swell. Science, 279, 1008-1011.Stern, R.J., and Dumitru, T.A., 2019, Eocene initiation of the Cascadia subduction zone: A second example of plume-induced subduction initiation? Geosphere, v. 15, 659-681.Whattam, S.A. and Stern, R.J., 2014. Late Cretaceous plume-induced subduction initiation along the southern margin of the Caribbean and NW South America: The first documented example with implications for the onset of plate tectonics. Gondwana Research, 27, doi: 10.1016/j.gr.2014.07.011.

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Emergence of plate tectonic during the Archean: insights from 3D numerical modelling.

10.5194/egusphere-egu21-8809 ◽

2021 ◽

Author(s):

Andrea Piccolo ◽

Boris Kaus ◽

Richard White ◽

Nicolas Arndt ◽

Nicolas Riel

Keyword(s):

Phase Transitions ◽

Subduction Zones ◽

Plate Tectonics ◽

Large Scale ◽

Potential Temperature ◽

Secular Change ◽

Plate Boundaries ◽

Plate Tectonic ◽

Subduction Initiation ◽

The Earth

In the plate tectonic convection regime, the external lid is subdivided into discrete plates that move independently. Although it is known that the system of plates is mainly dominated by slab-pull forces, it is not yet clear how, when and why plate tectonics became the dominant geodynamic process in our planet. It could have started during the Meso-Archean (3.0-2.9 Ga). However, it is difficult to conceive a subduction driven system at the high mantle potential temperatures (Tp) that are thought to have existed around that time, because Tp controls the thickness and the strength of the compositional lithosphere making subduction unlikely. In recent years, however, a credible solution to the problem of subduction initiation during the Archean has been advanced, invoking a plume-induced subduction mechanism[1] that seems able to generate plate-tectonic like behaviour to first order. However, it has not yet been demonstrated how these tectonic processes interact with each other, and whether they are able to eventually propagate to larger scale subduction zones.The Archean Eon was characterized by a high Tp[2], which generates weaker plates, and a thick and chemically buoyant lithosphere. In these conditions, slab pull forces are inefficient, and most likely unable to be transmitted within the plate. Therefore, plume-related proto-plate tectonic cells may not have been able to interact with each other or showed a different interaction as a function of mantle potential temperature and composition of the lithosphere. Moreover, due to secular change of Tp, the dynamics may change with time. In order to understand the complex interaction between these tectonic seeds it is necessary to undertake large scale 3D numerical simulations, incorporating the most relevant phase transitions and able to handle complex constitutive rheological model.Here, we investigate the effects of the composition and Tp independently to understand the potential implications of the interaction of plume-induced subduction initiation. We employ a finite difference visco-elasto-plastic thermal petrological code using a large-scale domain (10000 x 10000 x 1000 km along x, y and z directions) and incorporating the most relevant petrological phase transitions. We prescribed two oceanic plateaus bounded by subduction zones and we let the negative buoyancy and plume-push forces evolve spontaneously. The paramount question that we aim to answer is whether these configurations allow the generation of stable plate boundaries. The models will also investigate whether the presence of continental terrain helps to generate plate-like features and whether the processes are strong enough to generate new continental terrains&#160;or assemble them .&#160;[1]&#160;&#160;&#160;&#160;&#160;&#160; T. V. Gerya, R. J. Stern, M. Baes, S. V. Sobolev, and S. A. Whattam, &#8220;Plate tectonics on the Earth triggered by plume-induced subduction initiation,&#8221; Nature, vol. 527, no. 7577, pp. 221&#8211;225, 2015.[2]&#160;&#160;&#160;&#160;&#160;&#160; C. T. Herzberg, K. C. Condie, and J. Korenaga, &#8220;Thermal history of the Earth and its petrological expression,&#8221; Earth Planet. Sci. Lett., vol. 292, no. 1&#8211;2, pp. 79&#8211;88, 2010.[3]&#160;&#160;&#160;&#160;&#160;&#160; R. M. Palin, M. Santosh, W. Cao, S.-S. Li, D. Hern&#225;ndez-Uribe, and A. Parsons, &#8220;Secular metamorphic change and the onset of plate tectonics,&#8221; Earth-Science Rev., p. 103172, 2020.

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