Alteration Of The Surrounding Rock
An Overview of Hydrothermal Ore– Process Fluid Source, Compositions, and Transportation
Hydrothermal solutions cause alteration of the surrounding rock. Hydrothermal ore–forming processes can be found everywhere on Earth throughout the crust, most observed ore deposits have more than likely been touched by Hydrothermal ore–forming processes. Rose and Burt (1979) state that "Hydrothermal alteration is conversion of an initial mineral assemblage to a new set of minerals more stable under hydrothermal conditions of temperature, pressure, and most importantly, fluid composition" (p. 173). Hydrothermal alteration is considered a type of metamorphism, metamorphism is the recrystallization of a parent rock a more stable to new minerals. The type ... Show more content on Helpwriting.net ...Meteoric waters are widespread through the crust (because of the method of "delivery" being rain rainfall) and are associated with many types of ore formations. "The oxygen and hydrogen isotopes compositions of meteoric water, both surface and as groundwater, vary systematically over the entire globe as a function of latitude and elevation" (Robb, 2005, p 133). The way in which meteoric water is identified are the δD and δ18O isotopic values that land near or along this line δD=8×δ^18 O+10. Connate water(brines) also called formational water are inclusions in interstitial pores as deposited, which goes back to originally being meteoric water or sea water. Through the processes of burial, compaction, and lithification ore deposits form, because of the transformation of the sediment into lithified rock an aqueous solutions form ore deposits. The δD and δ18O isotopic values for connate waters range a great deal. The δD and δ18O isotopic values of oil field brines samples taken throughout North America exhibited a scattered from which each sample was taken.
Metamorphic waters ranges from high temperatures 300–600°C. Metamorphic waters are produces through the processes of dehydration and decarbonation reactions in the mid and lower crust. Change one mineral into another to create a more stable equilibrium at high
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