scholarly journals Noise in the Cretaceous Quiet Zone uncovers plate tectonic chain reaction

2021 ◽  
Author(s):  
Derya Guerer ◽  
Roi Granot ◽  
Douwe van Hinsbergen
Keyword(s):  
Subduction Zone ◽  
Mantle Plume ◽  
Plate Tectonics ◽  
Convergence Rates ◽  
Plate Motion ◽  
Plate Tectonic ◽  
Chain Reaction ◽  
African Plate ◽  
Mantle Dynamics ◽  
Chain Reactions

Global plate reorganizations, intriguing but loosely defined periods of profoundly changing plate motions, may be caused by a single trigger such as a continental collision or a rising mantle plume. But whether and how such triggers propagate throughout a plate circuit remains unknown. Here, we show how a rising mantle plume set off a ‘plate tectonic chain reaction’. Plume rise has been shown to trigger formation of a subduction zone within the Neotethys Ocean between Africa and Eurasia at ~105 Ma. We provide new constraints on Africa-Eurasia convergence rates using variations in geomagnetic ‘noise’ within the Cretaceous Normal Superchron (the 126-83 Ma period without magnetic reversals) recorded in the Atlantic Quiet Zones crust. These new constraints are consistent with the timing of numerically predicted African Plate acceleration and deceleration associated with onset and arrest of the intra-Neotethyan subduction zone. The acceleration was associated with a change in Africa-Eurasia convergence direction, which in turn was accommodated by a next subduction initiation at ~85 Ma in the Alpine region that cascaded into regional tectonic events. Our concept of plate tectonic chain reactions shows how changes in plate motion, underpinned by mantle dynamics, may self-perpetuate through a plate circuit, making global plate reorganizations a key to unlock the driving mechanisms behind plate tectonics.

scholarly journals Did plate tectonics control the generic diversity of Jurassic brachiopods? One point of view

Geologos ◽  
2018 ◽  
Vol 24 (1) ◽  
pp. 79-84
Author(s):  
Dmitry A. Ruban
Keyword(s):  
Plate Tectonics ◽  
Benthic Communities ◽  
Point Of View ◽  
Plate Motion ◽  
Northern Caucasus ◽  
Plate Tectonic ◽  
Α Diversity ◽  
Faunal Diversity ◽  
Swiss Jura ◽  
Diversity Dynamics

Abstract Possible plate tectonic controls on faunal diversity dynamics have been discussed in the geological literature for around 50 years. The new model of plate tectonic processes is here linked to Jurassic generic diversity (simple α-diversity) of brachiopods. This comparison offers three observations, four hypotheses and three unresolved issues. Most importantly, changes in the global plate root mean square speed coincided with brachiopod diversity dynamics, which can be explained hypothetically by either environmental disturbance triggered by more active plate motion or activity of any process (such as eustasy) tied to plate tectonic mechanisms and with an impact on marine benthic communities. It is also established that global generic diversity dynamics of brachiopods during the Jurassic coincided with the regional picture as established for the Northern Caucasus and the Swiss Jura Alps; this coincidence is difficult to explain with regard to plate tectonics. These and other speculative considerations do not clarify the role of the plate tectonic factor in Jurassic generic diversity dynamics of brachiopods, and, thus, they indicate important issues for further research.

Effect of plate motion on plume-induced subduction initiation

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

<p>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).</p><p>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.</p><p> </p><p>References:</p><p>Gerya, T., 2010, Introduction to Numerical Geodynamic Modelling.. Cambridge University Press.</p><p>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, 221–225.</p><p>Moore, W. B., Schubert, G. and Tackley, P., 1998, Three-dimensional simulations of plume-lithosphere interaction at the Hawaiian swell. Science, 279, 1008-1011.</p><p>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.</p><p>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.</p>

Plate tectonic chain reaction constrained from noise in the Cretaceous Quiet Zone

2020 ◽  
Author(s):  
Derya Gürer ◽  
Roi Granot ◽  
Douwe J.J. van Hinsbergen
Keyword(s):  
Subduction Zones ◽  
Kinematic Model ◽  
Plate Boundary ◽  
Western Mediterranean ◽  
Plate Motion ◽  
Plate Boundaries ◽  
Plate Tectonic ◽  
Test Bed ◽  
Chain Reaction ◽  
Tectonic Plates

<p>The relative motions of the tectonic plates show remarkable variation throughout Earth’s history. Major changes in relative motion between the tectonic plates are traditionally viewed as spatially and temporally isolated events linked to forces acting on plate boundaries (i.e., formation of same-dip double subduction zones, changes in the strength of the boundary), or thought to be associated with mantle dynamics. A Cretaceous global plate reorganization event has been postulated to have affected all major plates. The Cretaceous ‘swing’ in Africa-Eurasia relative plate motion provides an ideal test-bed for assessing the temporal and spatial evolution of both relative plate motions and surrounding geological markers. Here we show a novel plate kinematic model for the closure of the Tethys Ocean by implementing intra-Cretaceous Quiet Zone time markers and combine the results with the geological constraints found along the convergent plate boundary. Our results allow to assess the order, causes and consequences of geological events and unravel a chain of tectonic events that set off with the onset of horizontally-forced double subduction ~105 Myr ago, followed by a 40 Myr long period of acceleration of the Africa relative to Eurasia that peaked at 80 Myr ago (at rates four times as high as previously predicted). This acceleration, which was likely caused by the pull of two same-dip subduction zones was followed by a sharp decrease in plate velocity, when double subduction terminated with ophiolite obduction onto the African margin. These tectonic forces acted on the eastern half of the Africa-Eurasia plate boundary, which led to counterclockwise rotation of Africa and sparked new subduction zones in the western Mediterranean region. Our analysis identifies the Cretaceous double subduction episode between Africa and Eurasia as a link in the global plate tectonic chain reaction and provides a dynamic view on plate reorganizations.</p>

Eoarchean formation of the Isua supracrustal belt

2020 ◽  
Author(s):  
A Alexander G Webb ◽  
Thomas Müller ◽  
Jiawei Zuo ◽  
Peter Haproff ◽  
Anthony Ramírez-Salazar
Keyword(s):  
Plate Tectonics ◽  
Multiple Scales ◽  
Early Earth ◽  
Plate Tectonic ◽  
Mantle Dynamics ◽  
Change Models ◽  
Fine Grained ◽  
Tectonic Events ◽  
Supracrustal Belt ◽  
Major Shift

<p>A major shift in Earth’s crustal generation processes at ~3.2 to 2.5 Ga has been inferred from mineralogical, geological, and geochemical records, particularly those recorded by fine-grained sediments and zircon crystals. The most common hypothesis to explain this shift is the onset of plate tectonic recycling following some form of hot stagnant lid geodynamics. However, all prior detailed geologic studies of our best-preserved Eoarchean terrane, the ~3.85 - 3.60 Ga Isua supracrustal belt of SW Greenland, interpret this site to record terrane collision within the context of plate tectonics. This represents a significant counterweight to the assumption underpinning the ~3 Ga tectonic-mode-change models, i.e., the idea that early Earth’s record is broadly representative. The Isua belt is divided into ~3.8 and ~3.7 Ga halves, and these have been interpreted as plate fragments which collided by ~3.6 Ga. Here, we examine the evidence used to support plate tectonic interpretations, focusing on 1) reanalysis of prior geochronological results and associated cross-cutting relationships which have previously been interpreted to record as many as eight tectonic events, and 2) new field observations leading to reinterpretation of basic structural relationships. Simpler interpretations of the geochronological and deformation data are viable: the belt may have experienced nearly homogeneous metamorphic conditions and strain during a single deformation event prior to intrusion of ~3.5 Ga mafic dikes. Curtain and sheath folds occur at multiple scales throughout the belt, with the entire belt potentially representing Earth’s largest a-type fold. We propose a new model: two cycles of volcanic burial and resultant melting and TTG intrusion produced first the ~3.8 Ga rocks and then the ~3.7 Ga rocks above, after which the whole belt was deformed and thinned in a shear zone, producing the multi-scale a-type folding patterns. The Eoarchean assembly of the Isua supracrustal belt is therefore most simply explained by vertical-stacking volcanic and instrusive processes followed by a single shearing event. In combination with well-preserved Paleoarchean terranes, these rocks record the waning downward advection of lithosphere inherent in volcanism-dominated heat-pipe tectonic models for early Earth. These interpretations are consistent with recent findings that early crust-mantle dynamics are remarkably similar across the solar system’s terrestrial bodies.</p>

Application of stratigraphic frameworks and thermochronological data on the Mesozoic SW Gondwana intraplate environment to retrieve the Paraná-Etendeka plume movement.

2020 ◽  
Author(s):  
Florian Krob ◽  
Ulrich A. Glasmacher ◽  
Hans-Peter Bunge ◽  
Anke M. Friedrich ◽  
Peter C. Hackspacher
Keyword(s):  
Mantle Plume ◽  
Plate Tectonics ◽  
Convective Motion ◽  
Sedimentary Basins ◽  
Plate Motion ◽  
Data Sets ◽  
The Earth ◽  
Stratigraphic Framework ◽  
Sw Gondwana ◽  
Event Based

<p>Since plate tectonics has been linked to material flow in the Earth’s mantle, it is commonly accepted that convective motion in the sublithospheric mantle results in vertical deflections and horizontal plate motion on the Earth’s surface. Those mantle flow-driven vertical deflections are recognized through significant signals and traces in the sedimentary records (unconformities and missing sections). Recently, Friedrich et al. (2018) introduced an event-based plume stratigraphic framework that uses such signals in the stratigraphic record to detect the geological evolution near, and on the Earth’s surface in areas of interregional scale caused by mantle plume movement. Information about these dynamic processes is stored in geological archives, such as (1) stratigraphic records of sedimentary basins and (2) thermochronological data sets of igneous, metamorphic, and sedimentary rocks.</p><p>For the first time, this research combines these two geological archives and applies them to the Mesozoic SW Gondwana intraplate environment to retrieve the Paraná-Etendeka plume movement prior to the Paraná-Etendeka LIP. We compiled 18 stratigraphic records of the major continental and marine sedimentary basins and over 35 thermochronological data sets including >1300 apatite fission-track ages surrounding the Paraná-Etendeka Large Igneous Province to test the event-based plume stratigraphic framework and its plume stratigraphic mapping to retrieve the timing and spatial distribution of the Paraná-Etendeka plume.</p><p>The plume stratigraphic mapping, using the stratigraphic records is suitable to demark a possible plume center, plume margins and distal regions (Friedrich et al., 2018). Thermochronological data reveal centers of a significant thermal Paraná-Etendeka plume influence. Both archives show significant signals and traces of mantle plume movement well in advance of the flood basalt eruptions. Our LTT data combined with stratigraphic records are modeled successfully with respect to a viable mantle plume driven thermal evolution and therefore, we suggest that thermochronological data, in combination with stratigraphy records have the potential to retrieve the Paraná-Etendeka plume movement.</p>

scholarly journals Plume Versus Slab-Pull: Example from the Arabian Plate

2021 ◽  
Vol 9 ◽  
Author(s):  
Thamer Z. Aldaajani ◽  
Khalid A. Almalki ◽  
Peter G. Betts
Keyword(s):  
Mantle Plume ◽  
Plate Tectonics ◽  
Plate Motion ◽  
Arabian Plate ◽  
Rift System ◽  
Far Field ◽  
Buoyant Plumes ◽  
Field Plate ◽  
Break Up ◽  
Complex Structural

Mantle convection and the interaction of buoyant plumes with the lithosphere have been a significant influence on plate tectonics. Plume-lithosphere interactions have been regarded as a major driver of continental rifting, and have been linked to triple junction development and major supercontinent break-up events. There are also many extensional tectonic settings that lack evidence for a mantle plume and associated magmatism, indicating far-field plate stresses also drive plate fragmentation. The Arabian Plate is a spectacular active example where both a mantle plume and far-field plate stresses interact to drive continental break-up. Despite more than 80 years of geological research, there remains significant conjecture concerning the geodynamic processes responsible for the plate motion and the nature or onset of extension/deformation of the Arabian Plate. Complex structural patterns within the Arabian Plate have been interpreted in the context of tectonic plate movements and reorganization related to the subduction of the Tethys Oceanic plate, collision between Arabian and Eurasian plates, and the superposition of Afar plume. These interactions have accordingly resulted in different explanations or understanding of the geodynamic of the Afro-Arabian rift system. We assess the relative influence of plume vs. far field influences by reviewing the current views on the concept and models of these forces and highlighting their significance and implications on Arabia. Our synthesis shows that most of the geodynamical models proposed so far are not applicable to the entire Arabian Plate and its surrounding boundaries.

scholarly journals Indo-Atlantic plate accelerations around the Cretaceous-Paleogene boundary: A time-scale error, not a plume-push signal

Geology ◽  
2020 ◽  
Vol 48 (12) ◽  
pp. 1169-1173
Author(s):  
L. Pérez-Díaz ◽  
G. Eagles ◽  
K. Sigloch
Keyword(s):  
Time Scale ◽  
Plate Motion ◽  
Plate Tectonic ◽  
Flood Basalts ◽  
African Plate ◽  
Plate Motions ◽  
Motion Models ◽  
Reversal Time ◽  
Scale Error

Abstract It has been suggested that plume arrival at the base of the lithosphere introduces a push force that overwhelms the balance of torques driving plate circuits, leading to plate-tectonic reorganizations. Among the most compelling evidence in support of a “plume-push” mechanism is the apparent coincidence between eruption of the Deccan flood basalts around 67–64 Ma and a short-lived increase in Indian (and decrease in African) plate speed. Using existing and newly calculated high-resolution plate-motion models, we show that plate divergence rates briefly increased throughout the Indo-Atlantic circuit, contrary to the expected effects of plume-push. We propose that this circuit-wide spike in divergence rates is best explained as the artifact of a magnetic reversal time-scale error around the much studied Cretaceous-Tertiary boundary, and that the period spanning chrons C29–C28 lasted 70% longer than currently assumed. Corrected for this error, the residual long-term patterns of Indo-Atlantic plate motions and accompanying plate-tectonic reorganization are explicable in terms of maturation of the circuit’s spreading ridges, without invoking a significant plume-push force.

Orientation of absolute African plate motion revealed by tomomorphometric analysis of the Ethiopian dome

Geology ◽  
2000 ◽  
Vol 28 (12) ◽  
pp. 1147-1149 ◽  
Author(s):  
Bernard Collet ◽  
Jean François Parrot ◽  
Hind Taud
Keyword(s):  
Plate Motion ◽  
African Plate

scholarly journals Numerical models of slab migration in continental collision zones

Solid Earth ◽  
2012 ◽  
Vol 3 (2) ◽  
pp. 293-306 ◽  
Author(s):  
V. Magni ◽  
J. van Hunen ◽  
F. Funiciello ◽  
C. Faccenna
Keyword(s):  
Subduction Zone ◽  
Plate Tectonics ◽  
Numerical Models ◽  
Continental Collision ◽  
Force Balance ◽  
Small Scale ◽  
Dip Angle ◽  
External Forces ◽  
Stress Dependent ◽  
Subduction System

Abstract. Continental collision is an intrinsic feature of plate tectonics. The closure of an oceanic basin leads to the onset of subduction of buoyant continental material, which slows down and eventually stops the subduction process. In natural cases, evidence of advancing margins has been recognized in continental collision zones such as India-Eurasia and Arabia-Eurasia. We perform a parametric study of the geometrical and rheological influence on subduction dynamics during the subduction of continental lithosphere. In our 2-D numerical models of a free subduction system with temperature and stress-dependent rheology, the trench and the overriding plate move self-consistently as a function of the dynamics of the system (i.e. no external forces are imposed). This setup enables to study how continental subduction influences the trench migration. We found that in all models the slab starts to advance once the continent enters the subduction zone and continues to migrate until few million years after the ultimate slab detachment. Our results support the idea that the advancing mode is favoured and, in part, provided by the intrinsic force balance of continental collision. We suggest that the advance is first induced by the locking of the subduction zone and the subsequent steepening of the slab, and next by the sinking of the deepest oceanic part of the slab, during stretching and break-off of the slab. These processes are responsible for the migration of the subduction zone by triggering small-scale convection cells in the mantle that, in turn, drag the plates. The amount of advance ranges from 40 to 220 km and depends on the dip angle of the slab before the onset of collision.

Investigation of Mutations in Exon 12 Of MYH7, 16 Of β-MYBPC3 and 2 Of TCAP Gene in Dogs with Dilated Cardiomyopathy using PCR-SSCP Technique

2021 ◽  
Author(s):  
R.B. Vishnurahav ◽  
S. Ajithkumar ◽  
Usha Narayana Pillai ◽  
N. Madhvan Unny ◽  
K.D. John Martin ◽  
...  
Keyword(s):  
Polymerase Chain Reaction ◽  
Dilated Cardiomyopathy ◽  
Genetic Alterations ◽  
Chain Reaction ◽  
Multifunctional Protein ◽  
Chain Reactions ◽  
Polymerase Chain Reactions ◽  
Intron 1 ◽  
Cardiac Disorders ◽  
Polymerase Chain

Background: Dilated cardiomyopathy is the important myocardial disease and one of the most common cause of death in the medium to large size dog breeds worldwide. The disease is characterized by dilatation of cardiac chambers and thinning of walls leads to systolic failure. Mutations in some sarcomere genes leads to cardiomyopathy in humans. Sarcomere is an important multifunctional protein network involved in the signal reception and transduction. Mutations in β-MYH7, MYBPC3 and TCAP genes produce alterations in the morphology of heart (hypertrophy or dilatation).Methods: In this study twenty apparently healthy and twenty five dogs with dilated cardiomyopathy (DCM) were selected from patients reported or referred to University Veterinary Hospital and Teaching Veterinary Clinical Complex, Mannuthy (2015-2017) based on the clinical examination, radiographic, electrocardiographic, haematobiochemical and echocardiographic studies cardiac disorders (Dilated cardiomyopathy and hypertrophic cardiomyopathy) were confirmed.Result: In the present study we investigated genetic alterations of exon 12 of MYH7, 16 of β-MYBPC3 and 2 of TCAP gene in dogs by polymerase chain reaction -single stranded confirmation of polymorphism (PCR-SSCP). Polymerase chain reactions were analysed using acrylamide gel and samples with different pattern of bands were sequenced. Polymerase chain reaction-SSCP showed different migration of band pattern in the intron 1 of TCAP gene in one sample.

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