So why ask him in this thread then? - INTRANET CAFS | Colegio de Administradores de Fincas de Sevilla

So why ask him in this thread then?

I do not know how anybody can infer where these melts came from without knowledge of the available reservoirs. Well, perhaps. Originally Posted by marnixR Originally Posted by florian And no, I do not -deny- plate tectonics. Originally Posted by billiards Originally Posted by The Geographer Originally Posted by billiards I think I’m tending to agree that mantle convection is «bottom up».Dziewonski et al. So how can we get temperature differences into the mantle? …just by subduction of crust, so the first subducted cold plates sinking down to the mantle bottom could have created the upwelling zone at the bottom of the mantle which (maybe) had been not stable (just speculation). Earth Planet Sc Lett (2010) vol.

299 (1-2) pp. 69-79Discuss. its not just bottom up or top down its more complicated. I was also under the impression that the geochemical signatures showed signs of recycled sediments. Originally Posted by billiards I think I’m tending to agree that mantle convection is «bottom up».Dziewonski et al. We expect to see the transition zone thin if it is particularly hot, or thicken if it is cold. In fact there are other opinions out there (e.g. Another detail I have to mention are the magmatic series which are interpreted to be the hot upper zones of a blob of a plume and the colder bottom of those blobs, a plate tectonic model could not declare this so easily.Another word to the evidence for the start of plate tectonics in diamonds we can find little enclaves of eclogite or peridotit BUT the eclogite is everytime younger than 3.0 Ga and thats going to be interpreteted as the start of subduction like we know it and plate tectonicsThanks for your welcome greetings It is just another obsolete, refuted theory. how has it been refuted, in your eyes ?+ as an aside, if this thread becomes a carbon copy of the «plate tectonics» thread, we may have to merge them, or otherwise split off the «expanding earth – plate tectonics» posts Dziewonski, and Romanowicz et al.) and this is a question I am keen to explore in more detail. You need differences in the convecting system (not just vertical even horizontally) to get such big convection cells, if you have got a homogenous mantle there are no differences and you’ve got no convection.

There is definitely something very odd showing up in the transition zone 1000 km offset from the Hawaiian volcanism. What is observed is the transition zone bulges down, so it is thinner at the top (hot) and thicker at the bottom (cold). It is odd in that it doesn’t fit neatly into the thermal anomaly interpretation of the olivine phase transitions which are used so readily everywhere else. In particular I think the Large Low Shear Velocity Provinces (LLSVPs) at the core mantle boundary aka «super plumes» or «thermochemical piles» (depending on your preference), are interesting features worthy of discussion from the «bottom up» perspective. I’m not taking any sides on that debate, only sharing my interpretation of the Cao and van der Hilst paper. Later the core was created and stabilized the convection.PS: please mind at the beginning there had been no core, elements like uranium had been in the mantle and heated it up so at first there had been at least two mantle layers, so we should be talking about the point of time where the mantle had been convecting in one cell maybe at 3 Ga Originally Posted by billiards Well, perhaps.

My understanding was that there were two volcanic trends that are quite distinct yet remarkably persistent over the length of the chain. The real point is that it is the structures at the bottom of the Earth’s mantle that controls the pattern of mantle convection. I don’t say we know all about those islands that would be out of the range I think this paper opens a door to understand shallow mantle convection perhaps we even can declare by this «odd» issue those odd suboceanic magmatic «provinces» in the south of the hawaiian change which are a little bit younger (up to ca. 60 Ma IIRC) and look at the canary chain there you have those edge driven convection which is disturbing a plume (by the way the canary islands are one of the most interesting examples for hotspots there is a very good site unfortunatelly for you in german but the pictures of the modells are worth a look Der Kanarische Hotspot – Edge Driven Convection ). Mantle Anchor Structure: An argument for bottom up tectonics. Originally Posted by billiards So why ask him in this thread then? Yes, why not following the other thread? You need differences in the convecting system (not just vertical even horizontally) to get such big convection cells, if you have got a homogenous mantle there are no differences and you’ve got no convection. re-opened at request – but let’s try and stay clear from making this a «plate tectonics v.2» thread I do not know how anybody can infer where these melts came from without knowledge of the available reservoirs. Also I’m not fully convinced about those LLSVP’s like Burke argues, those provinces are existing nowadays ok, but that doesn’t have to be related to plate tectonics today.

Earth Planet Sc Lett (2010) vol. 299 (1-2) pp. 69-79Discuss. I think I’m tending to agree that mantle convection is «bottom up».Dziewonski et al. My understanding was that there were two volcanic trends that are quite distinct yet remarkably persistent over the length of the chain. We do not know what reservoirs are down there so it all seems like speculation as to whether it’s CMB material or whatever. The real point is that it is the structures at the bottom of the Earth’s mantle that controls the pattern of mantle convection. Last week I talked to one of my professors (about adakitic melts) and he said (I try to replay how it sounded to me though its translated very free) «well, there is – EVERYTHING». Mantle Anchor Structure: An argument for bottom up tectonics.

Originally Posted by billiards […]how do you argue about the moving of the mid atlantic Ridge? I think this question is central and we kind of let Florian get away with that statement. I would say, «my preference» is hard to describe, when I look at the empereor chain or at Tristan da Cunha my point of view is clearly ok, but I wouldn’t deny in general that there could have been a continent what was seduced by top-down elements. Earth Planet Sc Lett (2010) vol. 299 (1-2) pp. 69-79Discuss. its not just bottom up or top down its more complicated. Originally Posted by The Geographer Originally Posted by billiards I think I’m tending to agree that mantle convection is «bottom up».Dziewonski et al. That is what is meant by «bottom up» convection.

There is definitely something very odd showing up in the transition zone 1000 km offset from the Hawaiian volcanism. Mantle Anchor Structure: An argument for bottom up tectonics. Well one of the main points that this material came from somewhere… let’s say near to the D» layer is look at the length of this chain in central europe we have some things like Eifel, Rhön, Vogelsberg they didn’t last very long and those things seem to me to be from the transition zone. We do not know what reservoirs are down there so it all seems like speculation as to whether it’s CMB material or whatever.

To me I think it is a stretch to interpret this structure in terms of the temperature, it suggests there must be some chemical heterogeneity in that region and we cannot assume the structure is related to phase transitions in olivine. It is just another obsolete, refuted theory. Earth Planet Sc Lett (2010) vol. 299 (1-2) pp. 69-79Discuss. its not just bottom up or top down its more complicated. Wow! I’m impressed!

That’s the most clever text I ever read from you And no, I do not -deny- plate tectonics. ok, if that’s your reaction, then i close this thread + leave the «plate tectonics» thread as the only vehicle for the «florian vs. most other people» debate We expect coursework+essay
to see the transition zone thin if it is particularly hot, or thicken if it is cold. If you have a look here http://user.uni-frankfurt.de/~schmelin/convection1.mpg you can see that the convection is said not to be stable if you just mind the mantle but with the outter core and the crust being involved in the convection you get a stable convection Naturally a cold top is necessary in any convecting system. I do not know how anybody can infer where these melts came from without knowledge of the available reservoirs. Nobody can say how the CMB or the D» looked like 500 Ma before today so we should not forget other mechanisms which can drive bottom-up tectonics. (Main point that is disturbing me on burkes paper is his speculation on longterm stability) As for the isotope geochemistry, I would appreciate some kind of primer on that.

If you have a look here http://user.uni-frankfurt.de/~schmelin/convection1.mpg you can see that the convection is said not to be stable if you just mind the mantle but with the outter core and the crust being involved in the convection you get a stable convection I was also under the impression that the geochemical signatures showed signs of recycled sediments. Originally Posted by The Geographer You missed my point I will try to declare it on another way. My understanding was that there were two volcanic trends that are quite distinct yet remarkably persistent over the length of the chain. That is what is meant by «bottom up» convection. What is observed is the transition zone bulges down, so it is thinner at the top (hot) and thicker at the bottom (cold).

If you have a look here http://user.uni-frankfurt.de/~schmelin/convection1.mpg you can see that the convection is said not to be stable if you just mind the mantle but with the outter core and the crust being involved in the convection you get a stable convection Naturally a cold top is necessary in any convecting system. You missed my point I will try to declare it on another way. I was also under the impression that the geochemical signatures showed signs of recycled sediments.

It is odd in that it doesn’t fit neatly into the thermal anomaly interpretation of the olivine phase transitions which are used so readily everywhere else. We do not know what reservoirs are down there so it all seems like speculation as to whether it’s CMB material or whatever. I’m not taking any sides on that debate, only sharing my interpretation of the Cao and van der Hilst paper. To me I think it is a stretch to interpret this structure in terms of the temperature, it suggests there must be some chemical heterogeneity in that region and we cannot assume the structure is related to phase transitions in olivine.As for the isotope geochemistry, I would appreciate some kind of primer on that. Mantle Anchor Structure: An argument for bottom up tectonics.

Originally Posted by florian And no, I do not -deny- plate tectonics. It is just another obsolete, refuted theory. how has it been refuted, in your eyes ?+ as an aside, if this thread becomes a carbon copy of the «plate tectonics» thread, we may have to merge them, or otherwise split off the «expanding earth – plate tectonics» posts So why ask him in this thread then?