Questions tagged [geodynamics]

Geodynamics is the application of mathematics, physics, chemistry, geology, and computer science in understanding how mantle convection leads to plate tectonics.

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Least equatorial ( and tidal) bulge consistent with modest amounts of water in polar regions

In World Building I asked a question about the climate of an hypothetical planet. There Vogon poet said that Everyone above 10° latitude will be in permanent drought Considering that there were no ...
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How deep could an ocean trench be on Earth theoretically? [duplicate]

I was listening to a creepypasta story on YouTube about extremely deep places in the ocean deeper than the Marianas' Trench, and that makes me wonder. On Earth specifically, how deep could an ocean ...
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How plausible is it that "a portion of the ocean's floor" could suddenly be "thrown up to the surface" as described in this Lovecraft story?

This question came to me after reading H.P. Lovecraft's "Dagon"- the protagonist has fallen asleep drifting on the ocean in a small boat. He wakes up one morning to discover he's been ...
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Slab-breakoff - always connected to continent/continent collision?

The question came to me when pondering the Andes: Is a slab-breakoff always connected to the transition from subduction of oceanic crust to a continent/continent collision? Current understanding is ...
633 views

Are hot springs in non-volcanic areas radioactive?

Hot springs in non-volcanic areas are attributed to the interaction of water with hot rocks deep in the earth's crust: In non-volcanic areas, the temperature of rocks within the Earth also ...
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Gaps in locations of volcanos (Peru & Chile)

The figure below is taken from Reath, K. et al. (2019) A couple of things can be seen from this representation Volcanism seems to be strongly correlated with subduction zones, in this case the Nazca ...
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why continents do not subduct

In section 1.7 of Geodynamics by D. Turcotte & G. Schubet it is stated that "(...) continental crust cannot be destroyed by subduction" which I cannot completely understand. So far I ...
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Over what scales can we begin to apply fluid dynamics to accurately model properties of the mantle?

Over what size temporal/spatial scales do geophysicists and geodynamicists begin to apply fluid dynamics to model the mantle rather than elastic/plastic deformation theory?
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How much change has there been to the shape of plate boundaries over geological time?

This is a question that has bothered me for many years. As a new teacher I was asked this question by a 12 year old in our plate tectonics class. I said I would go away and find out. I would really ...
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What equation should I use in this isostasy problem?

I have this problem, and I am not sure where to start. The only Airy equation in my text is $r_1= \frac{h_1 \cdot p_u}{p_s - p_u}$. This doesn't seem to apply, or if it does it isn't obvious. Is ...
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Phase relation for mantle?

I have information about temperature, pressure, normal and shear stresses, viscosity, conductivity, density, heat capacity and adiabatic heating for a particular area of mantle in the form of 2D ...
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Why is the temperature between the earth core and surface not distributed linearly?

So I read somewhere that the inner core temperature of Earth might be as high as 7000 °C. Depending on the composition of the different layers towards the surface, the temperature should decline ...
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measuring fracture length and width using PKN and KGD models for hydraulic fracturing?

I am trying to understand PKN and KGD models for hydraulic fracturing. I am wondering why equations for fracture width and length does not include 'breakdown pressure' (pressure at which fracture ...
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Determining rotation of a bending detachment fault system

I would like to obtain the angle of rotation (𝛿θ) of a detachment fault (or oceanic core complex) after X meters of rock displaced during spreading at a mid-ocean ridge. I have a differential ...
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Are old geophysics textbooks useful?

I have had much success with old textbooks in mathematics. Generally, for any branch of mathematics that I (as a non-mathematician) would like to learn or re-learn, I can buy a classic textbook from ...
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Is the concept of seismogenic zone still relevant after the 2011 Japan earthquake?

The concept of subduction seismogenic zone, where megathrust seisms occur in a layer between an upper and a lower limit is well documented in the 1990/early 2000 literature : Some example : Pacheco,...
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Can the sealed bottle garden be called a perpetual motion machine? [closed]

I was not sure just where to ask this question, but I was wondering if the sealed bottle garden be really called a perpetual motion machine. http://www.dailymail.co.uk/sciencetech/article-2267504/The-...
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Can non-antipodal Chicxulub impact seismic wave be connected to Rio Grande Rift and Laramide Orogeny?

I have conducted a brief survey of Internet sources and cannot locate any definite discussion of a possible connection between the Chicxulub impact and the inception or acceleration of the Rio Grande ...
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Is there a differential angular rotation on Earth?

I asked a question about solar day difference between two latitudes on the same longitude here on the Earth surface. The answer was clear due to constant angular rotation time is the same. Tangential ...
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Why is the elevation of the Iberian Peninsula so high?

The Iberian peninsula lies more than 600 m above sea level, on average, far above similar geological regions in western Europe. Even tectonically undeformed areas in the inner basins present a ...
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State of Stress in rotated 2D system

I'm working on the rotation of the state of stress using the book Geodynamics of Turcotte page 101. The 2D coordinate system $x'$ and $y'$ is inclined at an angle $\phi$ with respect to the $x$, $y$ ...
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How to define the force at the base of an oceanic crust

In the book of Turcotte and Schubert, Geodynamics I'm trying to solve problem 2.8. The pressure in the water, in the oceanic crust, and in the mantle beneath the oceanic crust are (from equation 2.19,...
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When a tectonic plate subducts, does any of the subducted material melt, or is it just the mantle above the subducted slab that melts?

I know that water released from oceanic crust causes melting of the mantle in subduction zones, but does any part of the subducted slab melt as well - such as the sediments on the slab or the basalt? ...
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Does volcanic activity fluctuate?

According to this person's surmises, volcanic activity appers to be increasing. However, according to this report, volcanic activity is probably not increasing. My question is: Does Volcanic activity ...
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Are the processes of the rock cycle currently in dynamic equilibrium?

The standard representation of the rock cycle usually looks like this: Does each stage of the rock cycle currently balance? That is, are the various processes in dynamic equilibrium, so that the ...
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How can we determine the size and composition of Earth's inner core?

From Wikipedia: Earth's inner core is Earth's innermost part and is a primarily solid ball with a radius of about 1,220 km (760 mi). (This is about 70% of the Moon's radius.) It is believed to consist ...
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Could the Earth's core lose its heat?

Will all the drilling and digging to use the Earth's natural heat as geothermal energy affect the Earth's core, causing it to cool down? If so, would it result in an ice age? If not, how does the ...
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Phase changes deep in planetary interiors and their implications for surface tectonics

Earth's core mantle boundary represents a phase change from a solid (though convecting) mantle to a liquid Iron/Nickel core. This dramatic transition is likely the origin of the D" boundary, as well ...
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Why does Earth's outer-core rotate in the opposite direction to the inner-core?

Is it true that Earth's outercore rotates in the opposite direction to Earth's inner-core? Is there a plausible explanation for why this phenomenon occurs and what is the available evidence ...
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How do mantle plumes travel from the core of Earth to the crust?

As mantle plumes begin in the core and move towards the crust, I would have thought that the heat in the mantle plume would disperse to the surrounding mantle, and the plume would cease to exist by ...
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What are some of the strongest theories against the existence of mantle plumes?

Among the people I interact with in the geodynamics community, it seems that almost all of us are in full support of the mantle plume theory. What are the strongest arguments against this theory? Is ...
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Is the Yellowstone National Park unique for its geysers?

The Yellowstone National Park in Wyoming is unique for its large number of "thermal occurrences, of which there are some 30 geysers. This, in turn, appears to be the result of the presence of large ...
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