highest peaks on earth?

Discussion in 'Earth Science' started by EmptyForceOfChi, Nov 29, 2005.

  1. valich Registered Senior Member

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    The Himalayan Mountain Ranges is the most complex system of mountain-building orogeny on Earth. Evidence of previous upper volcanic activity and lower magma uplifts are extensively present over the entire Himalaya Belt.

    As the plates collided, the sinking Indian Plate generated extensive volcanoes in southern Tibet because the rock at the top of the plate melted from friction and huge pressures of the collision. Today, the tibetan Plateau is dotted with young volcanoes.

    The High Himalayas consist of a continuous belt of thick crustal stacking of metasedimentary and metaigneous rocks and associated granites, with a very complex deformational history. The base of the High Himalayas is made up of metamorphic rocks: schists formed from muds and sands that crystallised as a result of the collision. These are predominantly clastic metasedimentary rocks. Gneisses in this base layer are overlain by a thick layer of amphibolite calcareous rocks in many areas of central Nepalese Himalayas. Higher up are two huge bands of granite. Nearer the top the rocks are sedimentary. Within a few hundred metres of the summit is a formation known to climbers as the ‘Yellow Band’. This layer of shale, sandstone and limestone is made up of marine silts, clays and animal remains from the bed of the Tethys Ocean.

    The tectonostratigraphy of the Himalayan belt is divided into the Tibetan Himalaya, Greater Himalaya, Lesser Himalaya, and Subhimalaya zones. Separating the zones are major fault systems: the South Tibetan Detachment system (STDS) between the Tibetan Plateau and Higher Himalayas, the Main Central Thrust (MCT) between the Higher and Lesser Himalayas, and the Main Boundary Thrust (MBT) between the Lesser Himalaya and Subhimalaya. Other important structures include the Ramgarh and Main Frontal Thrusts (MFT) and the Lesser Himalayan duplex.

    The two parallel granite belts span the Higher Himalayas running parallel to the South Tibetan Detachment system (STDS). It is thought that these granite belts were formed during the evolution of the Main Central Thrust (MCT) from the (STDS): a decollement thrust. The (MCT) separates the high-grade metamorphic rocks of the Higher Himalaya crystalline hanging wall from the weakly metamorphosed series of the Lesser Himalaya footwall. The Main Frontal Thrust (MFT) is also decollement thrust with no basement involvement at least as far north as the downdip projection of the Main Boundary Thrust system (MBT). The (MBT) separates the metapsammitic schists and phyllites of the Lesser Himalaya hanging wall from the conglomerates and sandstones of the Sub-Himalaya footwall. The (MFT) is a low-angle, basal thrust along which the Indian plate is subducted beneath the Himalaya and southern Tibet and into which the (MBT) and (MCT) system root. The basal Himalayan Sole thrust (HST) becomes basement north of the downdip projection of the (MCT), or approximately at the latitude of the Himalayan range crest.
    (http://www.gsajournals.org/gsaonlin....1130/0091-7613(2003)031<0359:KMFTMC>2.0.CO;2)

    The two seperate granite belts are thought to have been created by discontinuous melting reactions during the thrust surface slip that dips shallowly through the metamorphically stratified crust. Depending on the position of magma emplacement above the (STDS), the spacing approximates the distance between the two plates. The granites are embedded within Tethyan medasedimentary rocks and appear to have high melting temperatures.
    http://sims.ess.ucla.edu/pdf/Harrison_et_al_GEOLOGY_1997.pdf

    Hot-spring waters near the Main Central Thrust (MCT) in the Marsyandi River of central Nepal are caused by hydrothermal interactions with the tectonic metamorphic flux processes below, indicative of magma activity. This area is marked by thrusting and active uplifting. The Marsyandi River marks the transition from a region of rapid uplift in the Higher Himalayan ranges to a region of slower uplift to the south. http://www.geo.cornell.edu/geology/research/derry/publications/Evans_Geology_01.pdf

    An active deformation of surface-rupture earthquakes, uplift of stream terraces, active foldinging and uplifting indicates that the Himalayan Frontal Thrust (HFT) and the Kunlun fault that divides the Tibetan Plateau are tectonically the most active zone areas across the whole of the Himalayas. (www.ias.ac.in/currsci/jun102004/1554.pdf)

    Apart from the strike-slip faulting there are important variations in compressional structural. The Main Mantle Thrust (MMT) of Indian continental crust beneath the principal Tethyan suture zone now has a vertical attitude suggesting a strong buckling component associated with this thrusting. It seems most likely that uplift along the northern Indus valley section occurred by buckle folding and East-West flattening. The transition between the thrust-fold geometries at Liachar portion of the MMT and the kilometric buckle fold at Sassi apparently involves a series of ductile shear zones exposed along the Ramghat section.
    http://earth.leeds.ac.uk/tectonics/nanga_parbat/parbatepsl.pdf

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    There are extensive igneous rock plutons formed from magma in the Northern Ignus-Tsangpo Suture Zone (ITSZ) formed due to melting of the crust during the terminal collision. the Main Central Thrust (MCT) brought the magma of the deep continental crust to lie on top of the Lesser Himalaya Zone (LHZ), Midland Formation in Nepal. This magma rose above the MCT lowering the solidus in the hot High Himalaya Crystalline Zone (HHCZ) and produced melts. The melt rose through the metamorphic piles along giant dykes and sills and emplaced at the contact between the HHCZ and High Himalaya Sedimentary Zone (HHSZ). Many of the Himalayan leucogranite plutons are indeed underlain and fed by giant dyke and sill complexes. However, there is no evidence of partial melting in the rocks occurring in the immediate hangingwall of the MCT, and the footwalls of the MCT is occupied by sedimentary or very low grade metamorphic rocks that do not appear to have given off large amount of fluid.

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    melting model for the Himalayan leucogranite. thrusting along MCT caused metamorphism in the footwall (LHZ) releasing H2O+CO2 fluid that triggered partial melting in the hangingwall (HHCZ). The melts emplaced at higher structural levels along giant dikes.

    Following the collision, the continued convergence resulted in the frontal part of the Indian plate to get thrusted back onto itself (reverse folding). This detachment is referred to as the Main Himalayan Thrust (MHT).

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    The frontal part of the Indian continental crust thrusted back onto itself along a northerly dipping detachment. This detachment is also called Main Himalayan Thrust (MHT) that extends into south Tibet and possibly north of Indus-Tsangpo Suture Zone (ITSZ). The black line above the Indian Ocean Crust represents partially molten crust, as imaged in seismic profiling. The calculated thermal structure shown assumes a horizontal MHT at a depth of 30 km and a depth to mantle at 80 km.

    Partial melting affects the thickened Himalayan crust, both along and across the orogen as well as at different depths. Depending on the values of heat-flow parameters, it is also possible for the transient geotherms to have steeper gradient than the initial (i.e., at the time of thrusting) geothermal gradient. Consequently, partial melting and emplacement of granitic magma may be continuing to the present day. Very young ages obtained from some of the plutons and high surface heat flow in Tibetan plateau supports this contention. This is also in conformity with the deduction from seismic data of a partial molten crust in southern Tibet.

    Sources:

    "A melting mechanism for the Himalayan leucogranite," by Dilip K. Mukhopadhyay, Journal of the Virtual Explorer, Vol. 11, 2003.
    http://www.virtualexplorer.com.au/2003/11/05/

    "Tectonics of the Himalaya and southern Tibet from two perspectives," K. V. Hodges, Geological Society of America Bulletin: Vol. 112, No. 3, pp. 324–350, 2000.
    http://www.gsajournals.org/gsaonlin...0.1130/0016-7606(2000)112<324:TOTHAS>2.0.CO;2
     
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  3. Ophiolite Valued Senior Member

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    None of which substantiates in anyway your false claim that Mount Everest arose from volcanic activity. You were wrong. You are wrong. And it appears that you intend to continue being wrong.
    The very data you are posting actually helps to demonstrate you are wrong, yet you appear to be unable to recognise this.
    Cut the crap vallich. Admit your error. Admit it now.
     
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  5. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

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    You were right, you are right and you will continue to be right about Vallich's inability to admit he was wrong. He has posted many pages of related cut and paste material but it does not appear to pass thru any human mind. He sometimes does not realize that his current cut and paste posts contradicts earlier ones. I am beginning to think he is not real flesh and blood, but a subroutine of Google as he often does turn up a lot of related information. I hope he continues this as I am able to throw out the trash.
     
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  7. Ophiolite Valued Senior Member

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    Being right is nice of course. Having three, four or five people in this thread point out he is wrong is even better. On an intellectual level this means the goal of preventing casual readers from being misled by his errors is prevented. However, on a visceral level it would be infinitely satisfying for the little turd to front up and admit he is wrong. It's a shame, as he does often turn up some interesting links. A pity he is unable to understand them.
     
  8. valich Registered Senior Member

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    3,501
    Again: "I believe in lifelong learning. As I learn, my knowledge base changes accordingly, and with that change comes an increase in understanding of the world around me, and a newer and hopefully better way of communicating that understanding to others. Am I not doing that on this forum?"

    If I at first suggested or implied that Everest was a volcano: YES!, I was wrong, and I quickly posted a rebuttal. That initial statement was due to the fact that I read that there are numerous pockets of volcanic basalts and magmatic granite in Mt. Everest.

    What is it that you want? I am posting posts that answer the questions asked on this forum. You are posting voidless criticisms that serve no useful purpose and wastes precious forum space that those of us that have a sincere desire to learn have to needlessly wade throuth.
     
  9. valich Registered Senior Member

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    3,501
    Check out this sketch of the Western Himalayas in East India and Pakistan. Isn't it fascinating? The India plate has actually produced a reverse upward southwest thrust (the magmatic Indus-Kohistan Seismic Zone). Notice the multiple faults and thrusts that overlie the Indian Plate above in the front.

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    The surface expression of the causal fault is marked by a line of landslides from Balakot to a few km SE of Muzaffarabad. The causal fault of Pakistan shows the active Murree/Muzafferabad fault....On hillsides not reamed clean by landslides near Balakot, a series of slumps or normal faults have developed above the inferred location of the reverse fault. (http://cires.colorado.edu/~bilham/Kashmir 2005.htm)
     
  10. Facial Valued Senior Member

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    2,225
    So - there's a section of the Indian plate that's sheared off under the Himalayas? Or is it still part of the Indian plate?

    What is a suture defined as anyways?
     
  11. invert_nexus Ze do caixao Valued Senior Member

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    9,686
    Valich,

    Several things.
    One is to learn. As you purport to be your purpose too.
    However. In regards to you, I have several other objectives.
    One of them is to get you to do this every time you are wrong:
    Why is it so hard to get you to admit you're wrong?
    Part of learning is learning where you erred. Part of learning where you erred (when in a public setting) is admitting those faults to those who you've made them to around you.
    It took how many posts to get you to admit that you were wrong?
    And even now you're using qualifiers such as 'if'.
    If you admit your erroneous conclusions everytime you make them rather than simply ignoring the people pointing out your failures and criticising them as 'criticisers', then we'd leave you alone. We'd not stop pointing out where you're wrong (when we know) but we'd be a lot more respectable towards you.

    Thank you, Valich. For finally. Admitting. That you were wrong about something.
    Finally.
    December 6th. Goes on my calendar.
     
  12. Ophiolite Valued Senior Member

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    9,232
    Thank you valich. That was all I was asking for. However, I fail to find the rebuttal. May I suggest in future you adopt the method followed by most posters on the forum and open such a rebuttal post with a phrase such as

    "Oops. I got this wrong."
    "Sorry. I was being a bit loose in my phrasing. That came out wrong."
    "Mistake. Heavan's de murgatroyd I made a mistake."
    "Mea culpa. Here is what I should have said"

    That is all we want valich, a direct acceptance that you have made an error. It should not have taken this many pages to get to this point. The responsibility for that lies with you.

    But again, thank you for acknowledging your error.
     
  13. invert_nexus Ze do caixao Valued Senior Member

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    Oh. By the way, while considering this later during work, I realized that Valich did retract his inital statement about 'volcanoes'. But, at the same time and later he added in the 'upwelling of magma' thing being behing the 'main central thrust' whatever.

    That's why we've been on your case, Valich. Because you retracted with one hand but kept on going with the other.
    And, even now, with this new perspective in hand, it seems as though you've only retracted your initial statement on volcanoes again but not the 'upwelling of magma'.
    However. I'll give you the benefit of the doubt on this one.


    The thing is, Valich, that there has been vulcanism that has contributed to the Himalayas. This is beyond doubt. Vulcanism in the past before India collided with Asia. And also some that took place during the collision. But, the thing that people have been trying to get you to admit (and hopefully you just have) is that the vulcanism is incidental to the whole affair. It's not even secondary. The force behind the height of the Himalayas is tectonic force (or something. I'm not an expert and am unsure of nomenclature) due to the Indian plate cramming itself up Asia's ass. The vulcanism that is seen in the area is a consequence of this rather than the other way around.
     
  14. genep Guest

    You guys are all wrong.
    The highest peak in the world has to be my ego.

    I should know because I always look down on the Himalayas.

    -- it's no joke, just the mind.
     
  15. Ophiolite Valued Senior Member

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    9,232
    We bow to your ultimately superior knowledge Genep. Chomolungma bows down to you.
     
  16. valich Registered Senior Member

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    3,501
    I'm not exactly sure how the multiple decollements in the Himalyas led to the multiple reverse thrusts. From reading the scientific journals, I know that the crust layering is still "not fully understand," so I'm not the only one. Very interesting subject.
     
  17. Ophiolite Valued Senior Member

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    9,232
    I don't understand your uncertainty.

    Firstly, we would not typically speak of a reverse thrust. A thrust is a reverse fault, so a reverse thrust would be rather like a double negative - in this case that would make it a normal fault: not at all what you meant. A more accurate usage would be to call it either a thrust fault, or a reverse fault, or even a reverse/thrust fault. Not all reverse faults are necessarily considered thrust faults. That term tends to be reserved for the low angle faults. It is these that are associated with decollements.
    That leads to my second area of puzzlement. Decollements are simply thrust faults, though ones in which the structural deformation of the rocks above and below the detatchment plane may be quite different. If we have multiple thrusts we must have the same number of multiple decollements, since in this context they are the same thing. What were you not understanding?
    The first decollements (from memory) were identified in the Alps, where overturned nappes of sedimentary rock had clearly been transported many miles over a low angle detatchment plane. Recognition of multiple nappes and their associated metamorphic and structural history have been key in understanding the geology of the British Caledonides [which may also have rivalled the Himalayas in size].
     
  18. valich Registered Senior Member

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    3,501
    Always quick to criticize: never any contribution to the forum.

    My first post about Everest was 11-30-05, 03:32 PM, and was then quickly followed by my corrected second post at 11-30-05, 06:41 PM in which I stated: "The finding of ocean-life fossils on top of Mount Everest indicate that it was not directly formed by a volcano." These two posts were only quickly interrupted by Ophiolite's posts, who is ALWAYS quickly prone to intercept as the "God of Earth Science" forums.

    I very quickly corrected my error, extremely quickly admitted to it, and went on with a much more detaled and explanatory post: posts that have never before been posted with such substaniated scientific detail on Sciforum. All the following details were factual information and cited from reputable scientfic sources.
     
  19. valich Registered Senior Member

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    3,501
    As posted, with scientific analysis, there is still an uprising of magma uplift in the Himalayas: multiple reverse thrust faults, earthquakes, volcanoes, hot spots, and thermal uprising.
     
  20. valich Registered Senior Member

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    3,501
    No! A reverse thrust fault is not "like a double negative." Nothing of the sort!

    Yes, it is a "low angle thrust fault." Reread your books. There is actually no reverse about it. It's just a matter of what part of the "decollement" thrusts below or above the other. Reread what a "decollement" is.
     
  21. Ophiolite Valued Senior Member

    Messages:
    9,232
    Not again vallich. Please not again.
    You falsely accused me of stalking you. I am beginning to think you are being deliberately contrary just to wind me up.
    Listen very carefully. A thrust fault is a form of reverse fault. The term reverse thrust makes absolutely no sense whatsoever.
    You state 'there is actually no reverse about it'. Of course there isn't. So why are you including it as a descriptive of thrust?
    Don't bother posting any more twaddles on this. Once again you are wrong. I am not going to indulge your fantasies any further. Back off.
     
  22. doodah Registered Senior Member

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    79
    Wow, there's hot spots in the Himalaya?

    Where have they been hiding all these years?
     
  23. valich Registered Senior Member

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    3,501
    You're not following the postings above. The Himalayas contain probably more hot spots then any other mountain range on earth - and it is very complex.

    I already stated "Hot-spring waters near the Main Central Thrust (MCT) in the Marsyandi River of central Nepal are caused by hydrothermal interactions with the tectonic metamorphic flux processes below... This area is marked by thrusting and active uplifting. The Marsyandi River marks the transition from a region of rapid uplift in the Higher Himalayan ranges to a region of slower uplift to the south. http://www.geo.cornell.edu/geology/..._Geology_01.pdf

    Countless neighboring "hot spots" can be similarly pointed out. It's an extremely complex system filled with "hot spots," underlying magma uplifts, and volcanic activity.
     

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