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Thread: Metamorphism

  1. #1 Metamorphism 
    ilg
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    Somehow I am confused with this,e.g,medium - high grade metamorphism of siliceous dolostone: diopside or dorsterite:
    1 tremolite + 3 calcite + 2quartz = 5diopside + 1H2O + 3 CO2
    1 tremolite + 11 dolomite = 8forsterite + 13 calcite + H2O + 9CO2
    why do 4 mineral assemblages can be produced ?
    Is there any website or books that teach how to determine the metamorphic processes/reaction by interpretating ACF diagram? Is that ACF may represents different things in ACF diagrams for different facies/zones ?


    Glacious


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    why do 4 mineral assemblages can be produced ?

    you know this Gibbs' phase rule - Wikipedia, the free encyclopedia ?

    Is there any website or books that teach how to determine the metamorphic processes/reaction by interpretating ACF diagram? Is that ACF may represents different things in ACF diagrams for different facies/zones ?


    Just remembering fragmentary... normally you've got one diagram for one facies. So you really need more than one diagram to say something about reactions. I have only a german book from Markl: minerals and stones (original in german: Minerale und Gesteine), he is doing very much stuff at thermometry and barometry. He quotes 12 important [metamorphic] reactions in metabasits, are you interested?


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  4. #3  
    ilg
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    Quote Originally Posted by The Geographer View Post
    why do 4 mineral assemblages can be produced ?

    you know this Gibbs' phase rule - Wikipedia, the free encyclopedia ?

    Is there any website or books that teach how to determine the metamorphic processes/reaction by interpretating ACF diagram? Is that ACF may represents different things in ACF diagrams for different facies/zones ?


    Just remembering fragmentary... normally you've got one diagram for one facies. So you really need more than one diagram to say something about reactions. I have only a german book from Markl: minerals and stones (original in german: Minerale und Gesteine), he is doing very much stuff at thermometry and barometry. He quotes 12 important [metamorphic] reactions in metabasits, are you interested?
    Thanks !!
    So what I can do is to remember the reaction + mineral assemblage by heart ? sometimes I do don't understand why the metamorphic reactions work in that way. For example, when one facies changes to another, e.g. prehnite-pumpellyite facies to greenschist facies, quartz can appear on the reactant side in one reaction but appears as products in another.
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    Quote Originally Posted by ilg View Post
    Quote Originally Posted by The Geographer View Post
    why do 4 mineral assemblages can be produced ?

    you know this Gibbs' phase rule - Wikipedia, the free encyclopedia ?

    Is there any website or books that teach how to determine the metamorphic processes/reaction by interpretating ACF diagram? Is that ACF may represents different things in ACF diagrams for different facies/zones ?


    Just remembering fragmentary... normally you've got one diagram for one facies. So you really need more than one diagram to say something about reactions. I have only a german book from Markl: minerals and stones (original in german: Minerale und Gesteine), he is doing very much stuff at thermometry and barometry. He quotes 12 important [metamorphic] reactions in metabasits, are you interested?
    Thanks !!
    So what I can do is to remember the reaction + mineral assemblage by heart ?
    for saying something about the reactions? I didn't get it you mean, you're standing in a laboratory having your mineral and whole rock assemblages? Or are you standing in the mountains with a rock in your hand and just looking at the minerals and you make a guess about how much percent quartz and other minerals is there in it?
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  6. #5  
    ilg
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    Quote Originally Posted by The Geographer View Post
    Quote Originally Posted by ilg View Post
    Quote Originally Posted by The Geographer View Post
    why do 4 mineral assemblages can be produced ?

    you know this Gibbs' phase rule - Wikipedia, the free encyclopedia ?

    Is there any website or books that teach how to determine the metamorphic processes/reaction by interpretating ACF diagram? Is that ACF may represents different things in ACF diagrams for different facies/zones ?


    Just remembering fragmentary... normally you've got one diagram for one facies. So you really need more than one diagram to say something about reactions. I have only a german book from Markl: minerals and stones (original in german: Minerale und Gesteine), he is doing very much stuff at thermometry and barometry. He quotes 12 important [metamorphic] reactions in metabasits, are you interested?
    Thanks !!
    So what I can do is to remember the reaction + mineral assemblage by heart ?
    for saying something about the reactions? I didn't get it you mean, you're standing in a laboratory having your mineral and whole rock assemblages? Or are you standing in the mountains with a rock in your hand and just looking at the minerals and you make a guess about how much percent quartz and other minerals is there in it?

    somehow my task is like...if I am give an ACF/A'KF diagram, I have to recognize or interpret the metamorphism reaction. Or the other way round, I am given the reaction and I have to draw the diagram out, say from A facies to B facies. I tried to link up minerals found in both facies and make a reaction equation but I failed to do so. I somehow just don't understand why the equation works that way.
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    Quote Originally Posted by ilg View Post
    Quote Originally Posted by The Geographer View Post
    Quote Originally Posted by ilg View Post
    Quote Originally Posted by The Geographer View Post
    why do 4 mineral assemblages can be produced ?

    you know this Gibbs' phase rule - Wikipedia, the free encyclopedia ?

    Is there any website or books that teach how to determine the metamorphic processes/reaction by interpretating ACF diagram? Is that ACF may represents different things in ACF diagrams for different facies/zones ?


    Just remembering fragmentary... normally you've got one diagram for one facies. So you really need more than one diagram to say something about reactions. I have only a german book from Markl: minerals and stones (original in german: Minerale und Gesteine), he is doing very much stuff at thermometry and barometry. He quotes 12 important [metamorphic] reactions in metabasits, are you interested?
    Thanks !!
    So what I can do is to remember the reaction + mineral assemblage by heart ?
    for saying something about the reactions? I didn't get it you mean, you're standing in a laboratory having your mineral and whole rock assemblages? Or are you standing in the mountains with a rock in your hand and just looking at the minerals and you make a guess about how much percent quartz and other minerals is there in it?

    somehow my task is like...if I am give an ACF/A'KF diagram, I have to recognize or interpret the metamorphism reaction. Or the other way round, I am given the reaction and I have to draw the diagram out, say from A facies to B facies. I tried to link up minerals found in both facies and make a reaction equation but I failed to do so. I somehow just don't understand why the equation works that way.
    as far as I remember we just did things like saying which minerals are in there, just interpreting a diagram, but it's a year gone and I don't remember how we did it, sorry.
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  8. #7  
    ilg
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    by the way, can someone explaned to me what is compositional zoning ? Where can I find a correct diagram ? I tried to google it, but there seems nothing or very little regarding on the definition/explanation + diagram of compositional zoning. THANKS
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    what do you mean by explane compositional zoning? Thats something for a crystall which has no specific composition though it depends on whole rock chemistry tempreature and pressure which elements will be installed in the crystall, though you won't find a really ever valid diagram.
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