Encrinite

Fossil skeletons of sea lilies

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The coloured objects in this image are fossil fragments of sea lilies or crinoids, marine organisms that were very common in the Mesozoic and Palaeozoic ages (between 540 and 66 million years ago) but that are now quite rare.

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Crinoids look like feathered flowers, but they actually contain a rigid calcite skeleton and it is in fact the ossicles of this skeleton that fossilize.

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These crinoid ossicles accumulated in a tropical sea of the Jurassic period, approximately 175 million years ago, and formed a rock known as “Fanes Encrinite”.

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At that time the Dolomites would probably have looked like the modern-day islands of the Bahamas.

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At the end of the lower Jurassic this shallow marine environment started to sink and became a seamount, that is an underwater mountain.

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The Fanes Encrinite was formed shortly before this happened, when these crinoids lived in waters that were only a few dozen metres deep.

Name: Encrinite
Classification: Carbonate rock, grainstone
Mineral composition: Calcite, Dolomite
Fossils: crinoids and other echinoderms, molluscs, brachiopods
Location: La Varella Refuge, Fanes Alps (46°36’48.35″N 12°0’24.42″E)
Formation: Fanes encrinite
Erà: Lower Jurassic (approximately 175 million years ago)
Depositional environment: Submerged carbonate substructure