#pyrite in the matrix because the Fe should've dropped out??? | Explore Tumblr Posts and Blogs

iamthepulta · 20 days

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Considering I waited until halfway through the trip to actually pick up rocks, I think I'm doing pretty good. GOD I just love skarns. They're so fun to think about. You get to poke around in their innards and mentally play with phase diagrams and chemistry and 3D puzzles and then you gotta map it and it's evil with the sun beating down on you. My brain's baked; that's what this field area does to you.

anyway I have some garnet and some glassy limonite and some really nice vesuvianite! And I also picked up some brecciated marble which is the weirdest thing in a hot minute. It's recrystallized, but with lineations, except the lineations were rotated after brecciation and reannealed with minimal (<1cm) matrix. It's very fun.

#ptxt #There's this really intense Fe metasomatism at our site and it's so cool to think about because the Fe clearly diminishes #But you have sulfides in the relatively unaltered core and at the edges of the tremolite; which is the Ca-Mg hydrated amph #If you look at the reaction Tremolite forms a hydrolysis reaction to form pyroxene; so I think it's possible that the trem formed first and #then that fluid sans Si neutralized in the middle and dropped the sulfides... but that still doesn't explain why you have so much #pyrite in the matrix because the Fe should've dropped out???#idek #If anyone wants to chime in on this chemistry; plz help because it'll haunt me for months.#I miss my lab. I wanted to put my chalcopyrites back in the furnace before I left but didn't.

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