Microstructures, diagenesis and seasonal evidences in Crassotrea sp. valves from Upper Albian-Lower
Cenomanian in the Somocuevas beach (Liencres, Cantabria)
The microstructural and cathodoluminescence (CL) study of Crassotrea sp. shells of Somocuevas, Cantabria
(Upper Albian-Lower Cenomanian) has allowed to determinate that the dominant diagenetic process
involved in the shells has been freatic meteoric, with cementaci贸n process in the pores and preservation
of the initial microstructure of the oysters. The main microstructures are: Regular simple prismatic (RSP),
Regular foliated (RF) and Complex cross foliated (CCF). These microstructures present a variable
luminescence. The RSP exhibits a yellow-bright luminescence. The RF is not luminescent or presents a dull
red luminescence, and the CCF has a medium to bright yellow luminescence. It is also observable the
presence of dark growth lines with yellow bright luminescence in the RF, that are related with fractures in
the umbo zone. It is proposed that these zones indicate anual growth lines that can be used to determinate
seasonalit
