A report on fluid inclusions, which are microscopic fluid ‘bubbles’ trapped inside mineral crystals for as much as a billion years, has been published. Geologists have found that these bubbles are useful clues in the search for ore deposits.
According to the author, Edwin Roedder, the U.S. Geological Survey report is the most comprehensive summary of the subject in the English language. Roedder explained that fluid inclusions might be considered as miniature Rosetta Stones or Dead Sea Scrolls of geology. ‘They are clues to geologic events of the fat past,’ he said, ‘when ore deposits were forming in baths of salty water. Evidences of the formation of ore deposits lie in the common occurrence of microscopic droplets of fluids that became trapped in growing mineral crystals deposited by the hot water solutions moving through cracks in rocks millions or even more than a billion years ago.’