80195619 Septarian concretion or (septarian nodules)
80195619 Septarian concretion or (septarian nodules), France, a dense mass formed by precipitation of mineral cement in sedimentary rock or soil which is later cracked and filled with other material, in this case calcite, Concretions are often ovoid or spherical in shape, although irregular shapes also occur. The word concretion is derived from the Latin con meaning together and crescere meaning to grow'. Concretions form within layers of sedimentary strata that have already been deposited. They usually form early in the burial history of the sediment, before the rest of the sediment is hardened into rock. This concretionary cement often makes the concretion harder and more resistant to weathering than the host stratum. John Cancalosi All images are copyright protected and remain the property of Ardea Picture Library Ltd. Permission for use is only granted once fee has been agreed and payment made and all digital files must be destroyed unless agreed otherwise in writing. Images must be credited: Photographer Name / ardea.com www.ardea.com
