Geology/minerals and temperature history
QUESTION: Dear Meisam,
Can you tell me at what temperature following minerals crystallize?
ANSWER: Dear Tariq,
Melting, freezing, and crystalization temperatures are only valid for pure substances. These minerals form in a variety of temperatures, pressures, and chemical compositions. It highly depends on the environment of their formation and ambient conditions. For example, calcite can crystalize from magma, can be a hydrothermal mineral, or can crystalize at ambient temperatures in oceans.
Whenever a mineral reaches saturation point it crystalizes.
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QUESTION: Thanks for answering me. Can you give me the range of temperatures of each mineral? If we get a calcite crystal in a well at 5km depth can we assume the maximum temperature the calcium carbonate fluids reached before converting crystalline calcite?
You can find the range of temperatures or pressures one particular mineral has formed in that particular conditions. But you have to consider the position of paleo-surface. The current depth observable for a mineral deposit might not be that when the mineral was formed.