marbleousmego:nettlewildfairy:the-late-great-abigail-quinn:marbleousmego:thepurplegeologist:the-late

marbleousmego:nettlewildfairy:the-late-great-abigail-quinn:marbleousmego:thepurplegeologist:the-late-great-abigail-quinn:the-late-great-abigail-quinn:relatetorocks:“Serpentine forms when very iron-rich rocks of the mantle combine with hot water.” Shell Beach-Sonoma Coast State Beach, Highway 1, California.  Magnesium. Serpentines are usually a magnesium phyllosilicate, Mg3Si2O5(OH)4. Iron can exchange for the Mg but under hydrothermal conditions fayalite (the Fe-olivine end member) is more likely to convert to iron ions or magnetite than enter serpentine. As a result hydrothermal alteration of mantle rock (rich in olivine) is produces serpentine in situ, and liberates iron to be precipitated out as an iron sulfide in black smokers on the ocean floor.#wait shit serpentine is real??? #i thought it was magical made up fantasy rockYeah it is! We have a ton of it on the West Coast, and anywhere else you see exposures of old ocean floor! There’s some down in Texas, probably some on the east coast, but yeah, shit tons in California and Oregon!It’s the state rock of California! It’s bright green! It also contains asbestos though so be careful around it. it looks very cool.there is a particular variety of serpantine is called lizardite. (also a real rock)Love the description! That was actually really useful since I’ll most likely be working with serpentinized rocks next year. Do y'all have any good suggestions for reading up on the process? I’m trying to self teach before school starts.What sort of work are you doing? If it’s on the geochem side Faure’s textbook is what I’ve been using, and it’s pretty good (but stressful as all heck). Anything that’s dealing with mining in California will have a lot (hydrothermal deposits being useful as all hell for copper mining), as will a textbook on metamorphic petrology. I bet @nettlewildfairy will have more useful/specific stuff, sounds like this is way in her wheelhouse!@marbleousmego​the us geological society and several california state parks have some pretty good basic details on the rocks. here is a good link to some more serpentine resources i dont have much in the way of metamorphic conditions charts since my study of the rock with my dissertation  has been largely structural and mapping based as opposed to formation conditions/ metamorphic  study. hopefully this tip can give you a few places where you can find more details.@the-late-great-abigail-quinn and @nettlewildfairy thanks for the resources!If all goes according to plan, I’ll be doing a fair bit of geochem, investigating adhesion surface preferences of extremophile biofilms in terrestrial analogs. A number of field sites I’ll have access to have serpentinite.I’m actually giving my yearly asbestos lecture in mineralogy today! Anyway, to edit a couple things above: serpentine is a class of minerals, not a single mineral. Serpentine minerals include antigorite, lizardite, and Chrysotile - their chemistries and structures are slightly different, and typically only Chrysotile curves itself into the asbestos needle shape. These are, as noted above, the result of alteration of high-magnesium rocks.Chrysotile is asbestiform, but not so concentrated in most places, even in california, that you would need to be concerned about your health. Usually, serpentine at the surface is exposed when continents close and high-magnesium, mantle minerals are exposed at the surface. These rock sequences are called “ophiolites” and they make good markers of former oceanic boundaries. The serpentine in California formed due to subduction off the west coast of the U.S., same thing with the serpentinite in Oregon and Washington. The Serpentine minerals in Texas formed over a billion years ago, but are still exposed today. Just to make it clear that some serpentine minerals aren’t hazardous, the green mineral standing behind this speaker is the serpentine mineral lizardite, quarried from Italy:I did a 3-part series on Serpentine minerals, asbestos, and diseases here a couple years ago: link.  -- source link

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