Mantle convection and stability of depleted and undepleted continental lithosphere

1997 ◽  
Vol 102 (B2) ◽  
pp. 2771-2787 ◽  
Author(s):  
Marie-Pierre Doin ◽  
Luce Fleitout ◽  
Ulrich Christensen
Keyword(s):  
Mantle Convection ◽  
Continental Lithosphere

Interaction of the Indian craton with the Reunion plume

2021 ◽  
Author(s):  
Jyotirmoy Paul ◽  
Attreyee Ghosh
Keyword(s):  
Mantle Convection ◽  
Geophysical Methods ◽  
The Other ◽  
Time Dependent ◽  
Indian Plate ◽  
Research Articles ◽  
Continental Lithosphere ◽  
Lithosphere Thickness ◽  
Indian Craton ◽  
Reunion Plume

<p>One of the fundamental characteristics of cratons is the presence of thick lithosphere of more than 200 km, whereas any standard non-cratonic lithosphere thickness is about 100 km thick. The thickness of Indian craton has remained quite controversial. Under the Indian plate, most seismic studies fail to recognise a thick lithosphere; however, a few studies using other geophysical methods (e.g., magnetotellurics) argue for a thick Indian craton. In the last 30 years, more than ten research articles estimated the thickness of the Indian craton that varied from less than 100 km to 260 km. Such controversy arose primarily because of the Reunion plume and Indian craton interaction at ~65 Ma. Some studies suggested that due to the Reunion plume's eruption underneath the Indian craton, the thick lithosphere of the Indian craton was thinned down. This thin lithosphere is attributed as one of the primary reasons for the acceleration of the Indian plate since 65 Ma. On the other hand, several studies advocated that the Reunion plume did not affect the thickness of the Indian craton. Still now, no study has actually investigated the nature of plume-craton interaction under the Indian plate and how the craton was deformed in the presence of a plume. In this study, we develop time-dependent global mantle convection models using CitcomS to understand the evolution of Indian craton for the last 100 Ma. The models are initiated at 100 Ma and are driven forward  up to the present day using reconstructed plate velocities at every 1 Myr interval. Our results show that it is possible to thin down the thicker cratonic lithosphere due to the eruption of the Reunion plume. We also observe that the plume could get bifurcated due to the craton, and eruptions could occur on both the eastern and western parts of the Indian continental lithosphere.</p>

Picrite-basalt complex in the Baoshan-Gongshan Block of northern Sibumasu: Onset of a mantle plume before breakup of Gondwana and opening of the Neo-Tethys Ocean

2021 ◽  
Author(s):  
Li Su ◽  
Shuguang Song ◽  
Chao Wang ◽  
Mark B. Allen ◽  
Hongyu Zhang
Keyword(s):  
Mantle Plume ◽  
Mantle Convection ◽  
Plate Tectonics ◽  
Southwest China ◽  
Volcanic Rocks ◽  
Geochemical Data ◽  
Continental Lithosphere ◽  
Geochronological Data ◽  
Induced Stress ◽  
Tethys Ocean

Mantle plumes are thought to play key roles in Earth’s geodynamics, including mantle convection, continental formation, and plate tectonics. The connection between plume activity and continental dispersion, as exemplified by the breakup of Gondwana and the generation of the Neo-Tethys Ocean, is a key question for the geosciences. Here, we present detailed investigations for the picrite-basalt sequence in the Baoshan-Gongshan Block of the northern Sibumasu terrane, southwest China. Field relations and petrological and geochemical data reveal that these volcanic rocks are continental flood picrites and basalts, consistent with a mantle plume origin. The estimated mantle potential temperatures range from 1527 ± 86 °C to 1546 ± 98 °C, and melting depths vary from the spinel to garnet stability fields (1.1−5.3 GPa), similar to Cenozoic Hawaiian picrites. Zircon geochronological data show that the mantle plume activity started at ca. 335 Ma and lasted to 280 Ma; this range is earlier than the breakup of the Gondwana continent and opening of the Neo-Tethys Ocean (270−260 Ma). We conclude that the long-lived mantle plume impacted the continental lithosphere but it did not drive continental breakup and the opening of Neo-Tethys Ocean, which took place because of the subduction-induced stress generated by initial subduction of the Paleo-Tethys Ocean.

PLANETARY SELF-ORGANIZATION

2020 ◽  
Vol 42 (3) ◽  
pp. 271-282
Author(s):  
OLEG IVANOV
Keyword(s):  
Dynamical System ◽  
Heat Source ◽  
Mantle Convection ◽  
Plate Tectonics ◽  
Rotation Speed ◽  
Self Organization ◽  
Heat Sources ◽  
Kinematic Parameters ◽  
The Earth ◽  
New Type

The general characteristics of planetary systems are described. Well-known heat sources of evolution are considered. A new type of heat source, variations of kinematic parameters in a dynamical system, is proposed. The inconsistency of the perovskite-post-perovskite heat model is proved. Calculations of inertia moments relative to the D boundary on the Earth are given. The 9 times difference allows us to claim that the sliding of the upper layers at the Earth's rotation speed variations emit heat by viscous friction.This heat is the basis of mantle convection and lithospheric plate tectonics.

Ups and Downs

2018 ◽  
Author(s):  
Roy Livermore
Keyword(s):  
Mantle Convection ◽  
Laboratory Experiments ◽  
Inner Core ◽  
Computer Modelling ◽  
Great Depth ◽  
New Horizons ◽  
The Core ◽  
The Earth ◽  
The World ◽  
The 1960S

Despite the dumbing-down of education in recent years, it would be unusual to find a ten-year-old who could not name the major continents on a map of the world. Yet how many adults have the faintest idea of the structures that exist within the Earth? Understandably, knowledge is limited by the fact that the Earth’s interior is less accessible than the surface of Pluto, mapped in 2016 by the NASA New Horizons spacecraft. Indeed, Pluto, 7.5 billion kilometres from Earth, was discovered six years earlier than the similar-sized inner core of our planet. Fortunately, modern seismic techniques enable us to image the mantle right down to the core, while laboratory experiments simulating the pressures and temperatures at great depth, combined with computer modelling of mantle convection, help identify its mineral and chemical composition. The results are providing the most rapid advances in our understanding of how this planet works since the great revolution of the 1960s.

scholarly journals Feedbacks between a non-Newtonian upper mantle, mantle viscosity structure and mantle dynamics

2020 ◽  
Vol 224 (2) ◽  
pp. 961-972
Author(s):  
A G Semple ◽  
A Lenardic
Keyword(s):  
Upper Mantle ◽  
Lower Mantle ◽  
Mantle Convection ◽  
Mantle Flow ◽  
Mantle Dynamics ◽  
Plate Motions ◽  
Low Viscosity ◽  
Mantle Viscosity ◽  
Flow Feature ◽  
Mantle Rheology

SUMMARY Previous studies have shown that a low viscosity upper mantle can impact the wavelength of mantle flow and the balance of plate driving to resisting forces. Those studies assumed that mantle viscosity is independent of mantle flow. We explore the potential that mantle flow is not only influenced by viscosity but can also feedback and alter mantle viscosity structure owing to a non-Newtonian upper-mantle rheology. Our results indicate that the average viscosity of the upper mantle, and viscosity variations within it, are affected by the depth to which a non-Newtonian rheology holds. Changes in the wavelength of mantle flow, that occur when upper-mantle viscosity drops below a critical value, alter flow velocities which, in turn, alter mantle viscosity. Those changes also affect flow profiles in the mantle and the degree to which mantle flow drives the motion of a plate analogue above it. Enhanced upper-mantle flow, due to an increasing degree of non-Newtonian behaviour, decreases the ratio of upper- to lower-mantle viscosity. Whole layer mantle convection is maintained but upper- and lower-mantle flow take on different dynamic forms: fast and concentrated upper-mantle flow; slow and diffuse lower-mantle flow. Collectively, mantle viscosity, mantle flow wavelengths, upper- to lower-mantle velocities and the degree to which the mantle can drive plate motions become connected to one another through coupled feedback loops. Under this view of mantle dynamics, depth-variable mantle viscosity is an emergent flow feature that both affects and is affected by the configuration of mantle and plate flow.

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