Microcrystalline gypsum
A rock of only micro chalk crystals
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This image shows extremely small gypsum crystals, visible only under the microscope: to the naked eye, this rock appears white and opaque.
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This particular sample was collected near the Dibona Hut and dates back to the upper Triassic (approximately 230 million years ago).
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Gypsum is an unusual rock, and it is formed in very particular environments: it derives from the evaporation of sea water in an extremely hot and dry climate.
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This can only happen in tropical latitudes, in environments close to the sea similar to salinas,
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and in extremely dry climates such as, for example, the shores of the Persian Gulf close to Abu Dhabi.
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Approximately 230 million years ago, the Dolomites would have been a coastal plain, at tropical latitudes and subject to an almost desert climate.
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If you want to get an idea of what that looked like, watch satellite images.In the sabkha of Abu Dhabi, gypsum is forming beneath a layer of dark mucilage that is clearly visible on satellite images.
References:https://www.environmentalatlas.ae/geographicInheritance/dunesAndSabkha
http://en.wikipedia.org/wiki/Sabkha
| Name: | Microcrystalline Gypsum |
| Classification: | Chemical sedimentary rock, evaporite |
| Mineral composition: | Gypsum |
| Fossils: | None |
| Location: | Dibona Refuse(46°32’5.09″N 12°4’21.20″E) |
| Formation: | Travenanzes formation |
| Era: | Upper Carnian (approximately 230 million years ago) |
| Depositional environment: | Sabkha |
