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The best argument I've heard supporting strong skepticism of plumes, if not total dismissal, is that the theory is too flexible. To put it more bluntly, this amounts to saying that it is unfalsifiable and therefore not helpful (in Popper's words, "A theory that explains everything, explains nothing.").
Erik Lundin, a Norwegian geologist, is a fairly ...
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How is ist possible that Mauna Loa Observatory is the International Reference Observatory for CO2 Global Meassurments
I don’t know that it is ‘the International Reference Observatory’. The Mauna Loa record is almost certainly the most-cited decadal-scale CO2 record, but as far as I know the observatory hasn't been accorded any special status: the record is ...
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First of all, the idea of a fixed "hotspot" reference frame is (albeit reluctantly) falling out of favour on a geological timescale; see e.g. http://onlinelibrary.wiley.com/doi/10.1029/GM121p0339/summary ("As studies of plate motions have advanced, however, it has become clear that the global hotspots do not stay fixed relative to each other...") and http://...
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The high values obtained when estimating the Rayleigh number for the mantle indicates that convection there is vigorous, and that convection is responsible for almost all the heat transported from the deep interior to the surface. Similar systems set up in the laboratory can develop 'plume-like' patterns of convective flow, and so mantle plumes are a ...
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Yes, Iceland is an example of a hotspot overlying a plume. The plume has been imaged seismically, e.g., see the Science paper (Figure 3) by Montelli et al. (2004). It is available at http://www.sciencemag.org/content/303/5656/338
The 2015 paper you referred doesn't dispute that claim. All is says is that "The plume split off a sliver of continent from ...
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As mentioned, the theory is so vague that it's impossible to falsify nor support it with present methods and data. Geologists can learn something about the limitation of tomographic models in this overview: Foulger et al 2013. Even the mantle plume model for the Emperor Chain have been challenged in some studies. One of the strongest arguments comes from ...
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Hot spots and ridges are two different things.
Hot spots stay in one place while the earth crust above them drifts and thus create a line of dormant volcanoes, they are a point features so to say.
Ridges are places where the mantle convection wells up and spreads in two directions, gently pulling the earth crust with them and creating new crust where the ...
2
hot spots help/control how spreading centers form but they are not what keeps them going.
If you push on a thin amorphous material perpendicular to the surface they tend to crack/split at three cracks roughly ~120 degrees to each other. If you push at several points close enough to each other these cracks will tend to link up as long lines with 120 degree ...
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As you probably know, the melting temperature in the mantle is a function of H2O contents. The more H2O you have, the lower the melting point of the rocks (i.e. dry vs wet solidus in the sketch). A less known phenomenon is the decrease of melting point with the addition of CO2.
The CO2 melting curve has a weird shape. At low pressures nothing much happens, ...
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