|Name:||Crinoids and other fossils in limestone|
|Classification:||Carbonate rock, oolitic-bioclastic grainstone|
|Mineral composition:||Calcite, Dolomite|
|Fossils:||crinoids and other echinoderms, molluscs|
|Location:||Dibona Refuge (46°32'1.61"N 12° 4'18.87"E)|
|Era:||Lower Carnian (approximately 235 million years ago)|
|Depositional environment:||Carbonate substructure|
The grey-blue star shaped object that stands out in this image is an ossicle (part of a calcareous skeleton) of a sea lily or crinoid, a marine organism that looks like a feathered flower and that was very common in the Triassic period. The dark objects in the photo are fragments of other marine fossils. This rock was formed from sand made up of fragments of shells which were subsequently cemented together.
The “cement” is made up of predominantly orange calcite crystals between the fragments. Buried marine sediments almost always end up in underwater aquifers with mineral rich waters. The calcite cement precipitates from this water, and this is the way almost all sediments turn into rock.