scholarly journals 888–444 Ma Global Plate Tectonic Reconstruction With Emphasis on the Formation of Gondwana

2021 ◽  
Vol 9 ◽  
Author(s):  
Christian Vérard
Keyword(s):  
Plate Tectonics ◽  
Additional Data ◽  
Continuous Process ◽  
Tectonic Activity ◽  
Plate Tectonic ◽  
Sea Floor ◽  
Tectonic Model ◽  
The Earth ◽  
Tectonic Reconstruction ◽  
Accretion Rates

The formation of Gondwana results from a complex history, which can be linked to many orogenic sutures. The sutures have often been gathered in the literature under broad orogenies — in particular the Eastern and Western Pan-African Orogenies — although their ages may vary a lot within those wide belts. The Panalesis model is a plate tectonic model, which aims at reconstructing 100% of the Earth’s surface, and proposes a geologically, geometrically, kinematically, and geodynamically coherent solution for the evolution of the Earth from 888 to 444 Ma. Although the model confirms that the assembly of Gondwana can be considered complete after the Damara and Kuunga orogenies, it shows above all that the detachment and amalgamation of “terranes” is a roughly continuous process, which even persisted after the Early Cambrian. By using the wealth of Plate Tectonics, the Panalesis model makes it possible to derive numerous additional data and maps, such as the age of the sea-floor everywhere on the planet at every time slice, for instance. The evolution of accretion rates at mid-oceanic ridges and subduction rates at trenches are shown here, and yields results consistent with previous estimates. Understanding the variation of the global tectonic activity of our planet through time is key to link plate tectonic modeling with other disciplines of Earth sciences.

scholarly journals 888 – 444 Ma global plate tectonic reconstruction with emphasis on the formation of Gondwana

2020 ◽  
Author(s):  
Christian Vérard
Keyword(s):  
Plate Tectonics ◽  
Additional Data ◽  
Continuous Process ◽  
Tectonic Activity ◽  
Plate Tectonic ◽  
Sea Floor ◽  
Tectonic Model ◽  
The Earth ◽  
Tectonic Reconstruction ◽  
Accretion Rates

<p>The formation of Gondwana results from a complex history, which can be linked to many orogenic sutures. Those sutures have often been gathered in the literature under broad orogenies — in particular the Eastern and Western Pan-African Orogenies — although their ages may vary a lot within those wide belts.</p><p>The Panalesis model is a plate tectonic model, which aims at reconstructing 100% of the Earth’s surface, and proposes a geologically, geometrically, kinematically, and geodynamically coherent solution for the evolution of the Earth from 888 Ma to 444 Ma. Although the model confirms that the assembly of Gondwana can be considered complete after the Damara and Kuunga orogenies, it shows above all that the detachment and amalgamation of “terranes” is a roughly continuous process, which even persisted after the Early Cambrian.</p><p>By using the wealth of Plate Tectonics, the Panalesis model makes it possible to derive numerous additional data and maps, such as the age of the sea-floor everywhere on the planet at every time slices, for instance. The evolution of accretion rates at mid-oceanic ridges and subduction rates at trenches are shown here, and yields results consistent with previous estimates. Understanding the variation of the global tectonic activity of our planet through time is key to link plate tectonic modelling with other disciplines of Earth sciences.</p>

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

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

<p>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 (<strong>Tp</strong>) that are thought to have existed around that time, because <strong>Tp</strong> 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.</p><p>The Archean Eon was characterized by a high <strong>Tp</strong>[2]<strong>, </strong>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 <strong>Tp, </strong>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.</p><p>Here, we investigate the effects of the composition and <strong>Tp </strong>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 <span>or assemble them </span></p><p>.</p><p> </p><p>[1]       T. V. Gerya, R. J. Stern, M. Baes, S. V. Sobolev, and S. A. Whattam, “Plate tectonics on the Earth triggered by plume-induced subduction initiation,” Nature, vol. 527, no. 7577, pp. 221–225, 2015.</p><p>[2]       C. T. Herzberg, K. C. Condie, and J. Korenaga, “Thermal history of the Earth and its petrological expression,” Earth Planet. Sci. Lett., vol. 292, no. 1–2, pp. 79–88, 2010.</p><p>[3]       R. M. Palin, M. Santosh, W. Cao, S.-S. Li, D. Hernández-Uribe, and A. Parsons, “Secular metamorphic change and the onset of plate tectonics,” Earth-Science Rev., p. 103172, 2020.</p>

Introductory remarks

1980 ◽  
Vol 297 (1431) ◽  
pp. 137-138
Keyword(s):  
Mantle Convection ◽  
Plate Tectonics ◽  
Sharp Change ◽  
Indirect Approach ◽  
Sea Floor ◽  
Wave Velocities ◽  
The Earth ◽  
Magnesium Silicates ◽  
Sea Floor Spreading ◽  
Seismic Discontinuity

The substratum of the Earth, as Arthur Holmes originally described it, now generally known as the mantle , is the envelope, mainly of magnesium silicates, surrounding the fluid metallic core. It is separated from the continental and oceanic crusts which overlie it by the Mohorovicic seismic discontinuity, where there is a sharp change from earthquake wave velocities less than 7.2 km s -1 above to 7.8-8.1 km s -1 below. The thickness of the envelope is of the order of 2900 km, compared with about 4 km for ocean crust and 30 km for unthickened continental crust. Much attention has been devoted by geophysicists to the properties of the mantle, particularly in the course of the Geodynamics Project of I.U.G.G./I.U.G.S., during which important conclusions regarding sea floor spreading, plate tectonics and mantle convection have been reached. The fact that the overwhelming bulk of the mantle is not, and never will be, accessible for direct collection has perhaps resulted in less interest so far from the geochemical side. Accepting, however, that a partly indirect approach is inevitable, the time is now ripe for a thorough examination of the contribution that geochemical techniques can make.

scholarly journals Geodynamic evolution of the Earth over the Phanerozoic: Plate tectonic activity and palaeoclimatic indicators

2015 ◽  
Vol 4 (2) ◽  
pp. 167-188 ◽  
Author(s):  
Christian Vérard ◽  
Cyril Hochard ◽  
Peter O. Baumgartner ◽  
Gérard M. Stampfli ◽  
Min Liu
Keyword(s):  
Tectonic Activity ◽  
Plate Tectonic ◽  
Geodynamic Evolution ◽  
The Earth

scholarly journals A Geologist Reflects on a Long Career

2018 ◽  
Vol 46 (1) ◽  
pp. 1-20 ◽  
Author(s):  
Dan MKenzie
Keyword(s):  
Plate Tectonics ◽  
Continental Drift ◽  
Temperature Structure ◽  
Earth’S Gravity Field ◽  
Plate Motions ◽  
Sea Floor ◽  
Long Wavelength ◽  
Geological Processes ◽  
The Earth ◽  
Sea Floor Spreading

Fifty years ago Jason Morgan and I proposed what is now known as the theory of plate tectonics, which brought together the ideas of continental drift and sea floor spreading into what is probably their final form. I was twenty-five and had just finished my PhD. The success of the theory marked the beginning of a change of emphasis in the Earth sciences, which I have spent the rest of my career exploring. Previously geophysicists had principally been concerned with using ideas and techniques from physics to make measurements. But the success of plate tectonics showed that it could also be used to understand and model geological processes. This essay is concerned with a few such efforts in which I have been involved: determining the temperature structure and rheology of the oceanic and continental lithosphere, and with how mantle convection maintains the plate motions and the long-wavelength part of the Earth's gravity field. It is also concerned with how such research is supported.

From crisis to normal science, and back again: Coming full “Kuhn cycle” in the career of Warren B. Hamilton

2022 ◽  
Author(s):  
Thomas Rossetter
Keyword(s):  
Plate Tectonics ◽  
Earth Science ◽  
Scientific Change ◽  
Normal Science ◽  
Plate Tectonic ◽  
New Paradigm ◽  
Tectonic Model ◽  
New Period ◽  
The 1960S ◽  
New Phase

ABSTRACT In this paper, I use Thomas S. Kuhn’s model of scientific change to frame a brief, broad-brushed biographical sketch of the career of Warren B. Hamilton. I argue that Hamilton’s career can usefully be interpreted as encompassing a full “Kuhn cycle,” from a period of crisis in his early work, to one of normal science in midcareer, and back to something resembling crisis in his later research. Hamilton entered the field around mid-twentieth century when earth science can plausibly be described as being in a period of crisis. The then dominant fixist paradigm was facing an increasing number of difficulties, an alternative mobilist paradigm was being developed, and Hamilton played an important role in its development. The formulation of plate tectonics in the 1960s saw the overthrow of the fixist paradigm. This inaugurated a new phase of normal science as scientists worked within the new paradigm, refining it and applying it to different regions and various geological phenomena. Hamilton’s midcareer work fits largely into this category. Later, as the details of the plate-tectonic model became articulated more fully, and several of what Hamilton perceived as weakly supported conjectures became incorporated into the paradigm, problems began again to accumulate, and earth science, in Hamilton’s estimation, entered a new period of crisis. Radically new frameworks were now required, and Hamilton’s later work was dedicated principally to developing and articulating these frameworks and to criticizing mainstream views.

Analysing the tidal state of a pre-plate tectonic Earth during the Archean Eon (3.9 Ga)

2021 ◽  
Author(s):  
Hannah Davies ◽  
Mattias Green ◽  
João Duarte
Keyword(s):  
Plate Tectonics ◽  
Early Time ◽  
Open Ocean ◽  
Day Length ◽  
Plate Tectonic ◽  
Deep Time ◽  
The Earth ◽  
Tidal State ◽  
Tidal Energetics ◽  
Tectonic Features

<p>Deep time investigations of the Earth have revealed a relationship between plate tectonic motion and the intensity of the tide. Tidal energetics change as continental plates disperse and aggregate in the supercontinent cycle, altering ocean basins around them. The question is, could enhanced tides occur on Earth before plate tectonics started e.g., during the Archean?  </p><p>Here we have coupled an established tidal model with an ensemble of potential topographies of the Archean Earth to establish a statistically significant approximation of Archean tidal energetics. Land area is restricted to 5 – 15% with the rest representing primordial ocean – containing no major plate tectonic features i.e., trenches and ridges. Ocean volume is preserved at close to present-day which means oceans are on average 1 km shallower than present-day oceans. Archean day length is set at 13.1 hours with the semi-diurnal tide occurring every 6.8 hours. Equilibrium tide is around 3.4x the present-day value due to the proximity of the Moon.</p><p>The aim of this study is to assess the relationship of the Earth Moon system during this primordial stage to better understand the potential role tides had in the origin of life, and to quantify the tidal state of a primordial rocky planet with a young, nearby moon. Understanding the tidal state of Earth at this early time is important for exoplanetary studies as it broadens our scope of planets which may be hospitable to life.</p><p>We found coastal and open ocean resonance in many of the ensemble topographies. Total global dissipation in the ensembles varies from 75 – 150% of present-day dissipation rates due to elevated equilibrium tide and greater area where the tide can dissipate. When regional and open ocean resonance does occur, it can raise total global dissipation to >150% of present-day values and can cause regional macrotidal amplitudes (>2m).</p>

scholarly journals The diversity of tectonic modes and thoughts about transitions between them

2018 ◽  
Vol 376 (2132) ◽  
pp. 20170416 ◽  
Author(s):  
A. Lenardic
Keyword(s):  
Plate Tectonics ◽  
Chemical Properties ◽  
Process Variable ◽  
Tectonic Activity ◽  
Tectonic Deformation ◽  
Terrestrial Planets ◽  
Plate Tectonic ◽  
Chemical Conditions ◽  
Physical And Chemical ◽  
Earth Dynamics

Plate tectonics is a particular mode of tectonic activity that characterizes the present-day Earth. It is directly linked to not only tectonic deformation but also magmatic/volcanic activity and all aspects of the rock cycle. Other terrestrial planets in our Solar System do not operate in a plate tectonic mode but do have volcanic constructs and signs of tectonic deformation. This indicates the existence of tectonic modes different from plate tectonics. This article discusses the defining features of plate tectonics and reviews the range of tectonic modes that have been proposed for terrestrial planets to date. A categorization of tectonic modes relates to the issue of when plate tectonics initiated on Earth as it provides insights into possible pre-plate tectonic behaviour. The final focus of this contribution relates to transitions between tectonic modes. Different transition scenarios are discussed. One follows classic ideas of regime transitions in which boundaries between tectonic modes are determined by the physical and chemical properties of a planet. The other considers the potential that variations in temporal evolution can introduce contingencies that have a significant effect on tectonic transitions. The latter scenario allows for the existence of multiple stable tectonic modes under the same physical/chemical conditions. The different transition potentials imply different interpretations regarding the type of variable that the tectonic mode of a planet represents. Under the classic regime transition view, the tectonic mode of a planet is a state variable (akin to temperature). Under the multiple stable modes view, the tectonic mode of a planet is a process variable. That is, something that flows through the system (akin to heat). The different implications that follow are discussed as they relate to the questions of when did plate tectonics initiate on Earth and why does Earth have plate tectonics. This article is part of a discussion meeting issue ‘Earth dynamics and the development of plate tectonics’.

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