| Ooids |
Articles about Ooid |
Information AboutOoids |
| CATEGORIES ABOUT OOID | |
| sedimentary rocks | |
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An ooid forms by a series of concentric layers around a nucleus. The layers contain crystals arranged radially, tangentially or randomly. The nucleus can be a shell fragment, quartz grain or any other small fragment (including an aragonite/calcite amalgamation). Modern ooids are exclusively aragonite (a neomorph of calcite). Ancient ooids are calcite, which is either a replacement of aragonite or directly precipitated. Similar to a snowball, which accumlates more snow as it rolls down a hill, ooids form by growing larger and accreting material as they move around. There are several factors that affect ooid growth: supersaturaiton of the water with respect to calcium carbonate, the availability of nuclei, agitation of the ooids, a constant location, water depth and the role of microbial organisms. Kidney Stone s are a type of ooid, as they are rich in calcium and possess similar growth structures. EXTERNAL LINKS |
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