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Showing results for tags 'calcium'.
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Davemaoite, a new mineral from the lower mantle, found in diamond
Oxytropidoceras posted a topic in Rocks & Minerals
Diamond delivers long-sought mineral from the deep Earth Davemaoite is a vehicle for radioactive isotopes that help to heat the planet’s mantle. Alexandra Witze, Nature News Diamond from Lower Mantle Found with a New Type of Mineral; High-Pressure Silicate Material Davemaoite Discovered Second to Bridgmanite Ron Jefferson, Science Times, Nov 12, 2021 Diamond hauled from deep inside Earth holds never-before-seen mineral Researchers thought the mineral was impossible to find on Earth's surface By Harry Baker, Live Science, November 11, 2021 The paper is: Tschauner O, Huang S, Yang S, Humayun M, Liu W, Gilbert Corder SN, Bechtel HA, Tischler J, Rossman GR. Discovery of davemaoite, CaSiO3- perovskite, as a mineral from the lower mantle. Science. 2021 Nov 12 374(6569):891-894. doi: 10.1126/science.abl8568. Epub 2021 Nov 11. Yours, Paul H.-
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I have some Cucullaea gigantea mud impressions with shell fragments still left. These fragments are extremely fragile. Is there anyway to store or preserve them to keep the shell pieces on?
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Hello, I have many crinoid columnals that I collected in gravel (I suppose it was river/creek gravel collected and sold by a "sand and gravel" company) in Illinois many years ago. I have two questions that may be obvious to more seasoned fossil hunters/students. 1) Exactly how did the crinoids actually grow, meaning, how did the stems' diameter expand horizontally in size as time went on, since the stems were mostly composed of hard calcium carbonate/lime. In other words, it seems that once they are "hardened" or "frozen" into a certain size, how can they get bigger? Was there growth tissue on the OUTSIDE of the stem that kept adding on calcium to the inside, like tree trunks creating wood and bark? (I can understand the growth of whorled type seashells, but I can't get this through my head.) 2) Many of the columnal discs/segments I have found are virtually solid silica, some with a glossy almost pearly luster, I suppose would be classified as flint, chert or chalcedony. I assume from what I've read that this is from replacement of the original calcium with silica over a long period of time. This may seem simple-minded or thinking too deeply, but do researchers claim to understand how the silica could actually have "moved" or migrated into the spaces where the calcium used to be? I can't visualize how this would be possible. Like, one molecule at a time gradually moves through solid rock? Does anyone understand why this seems so hard for me to visualize? Or is this believed to occur because the original calcium actually changes it's molecular characteristics without moving? Any input or comments would be greatly appreciated!
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- below lomita marl
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