2016 Volume 70 Issue 2 Pages 45-64
During Messinian Period, evaporates were widely deposited in Paleo-Mediterranean Sea. The Sorbas Basin, southeastern Spain, is situated near the Strait of Gibralter between the Atlantic Ocean and the Mediterranean Sea, and was a part of the Paleo-Mediterranean Sea. The changes of both planktic and benthic foraminiferal assemblages from the Abad Member, Turre Formation distributed in the Sorbas Basin were investigated to reconstruct long-term paleoenvironmental change in this basin during early Messinian Period.
The occurrence of Globorotalia miotumida from the basal part of the Abad Member and disappearance of this species in the middle part of this member indicate that the base of this member is younger than 7.246Ma and lower half of this member is older than 6.506Ma. The coiling direction of Neogloboquadrina acostaensis suggests that the most of the Abad Member is older than 6.337Ma.
On the basis of faunal change of planktic foraminifers, following surface conditions alternatively occurred during the deposition of the Abad Member; warm and shallow mixing layer, cool and shallow mixinglayer, and cool and deep mixing layer. This environmental change might represent the cyclic change of the surface water condition proposed by Sierro et al. (2003). Salinity of the surface water increased during the deposition of the Abad Member. The bottom environment was also reconstructed on the basis of benthic foraminifers. In long term, the bottom condition was controlled by the decrease of the paleo-water depth and disoxygenation of deep water probably caused by uplifting of the Sorbas Basin and the stagnation of bottom water, respectively.
