Location: Cuenca, Spain
Age: Barremian (Lower Cretaceous)
The Las Hoyas Lagerstatte is Barremian (Lower Cretaceous) in age, which ranges from 121-127 million years ago (Ma). Most of the more important fossils come from a particular horizon dated at 115Ma. It belongs to the extensive Calizas de la Huerguina Formation, which is lacustrine and palustrine in origin. These sediments are all fine-grained, rhythmically laminated, lacustrine or palustrine carbonate limestones, deposited in sub-tropical and semi-arid conditions.
Figure 1 shows what they look like in outcrop: (please click on the thumbnails for larger images).
Evidence that the sediments were deposited in a lake is the terrestrial palaeosols associated with them. The fern assemblage in these rocks show they are similar to the English Wealden facies. Freshwater microfossils can be observed in the rocks, again showing a lacustrine setting. These Charophytes are important biostratigraphic markers. Figure 2 shows a Charophyte and the fine grained matrix of the limestone.
Also indicative of freshwater conditions is the presence of freshwater gastropods seen in figure 3.
Proceed to section 3: Flora and Fauna
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