Premilinary integrated magnetostratigrafía and biostratigraphic correlation in the Miocene Lorca basin, (Murcia, SE Spain)

Abstract

The Lorca basin is one of the Neogene basins of South Eastern Spain. The infilling Tortonian-Messinian deposits are mainly composed of marls and reach up to 1,200 m in thickness. A biostratigraphic survey of these deposits, assisted by the determination of the magnetic polarity reversal pattern for most of these deposits (900 m), has enabled the Tortonian-Messinian chronostratigraphy to be precised.
The close sampling space for biostratigraphic determination has enabled the accurate location of four main biostratigraphic events than can be correlated with charactenstic events of the Mediterranean biostratigraphic Zones. In addition, the location of  the Tortonian/Messinian boundary has been accurately placed at some 150 m below the main gypsum unit outcropping in the basin. The integrated bio-magnetostratigraphic
data from the studied section allows a tentative interpretation of the identified magnetozones. Thus, a correlation to the Geomagnetic Polarity Time Scale is presented for more than 900 m of pre-evaporite Miocene stratigraphic succession from the Lorca basin.
Moreover, about 15" of anticlockwise rotation has been detected. Its significance is evaluated in the basin geodynamic framework.