Lower Valanginian ammonite biostratigraphy in the Subbetic Domain (Betic Cordillera, southeastern Spain)

Abstract

A new zonation for the lower Valanginian in the Betic Cordillera is presented. It is based on the study of 16 sections located near Caravaca and Cehegín (Region of Murcia). From bottom to top, the following interval zones, defined by the first appearance of the index-species, are distinguished: • "Thurmanniceras" pertransiens Zone, which can be subdivided into two subzones, a lower "Th." pertransiens Subzone and an upper Vergoliceras salinarium Subzone. The latter is characterized by the disappearance of Olcostephanus drumensis and the appearance of Luppovella superba. • Neocomites neocomiensiformis Zone, also with two subzones, the Baronnites hirsutus Subzone below (characterized by the appearance of "Busnardoites" subcampylotoxus and Olcostephanus guebhardi) and the Valanginites dolioliformis Subzone above ("Busnardoites" campylotoxus is restricted to this subzone). • Karakaschiceras inostranzewi Zone, subdivided as well into two subzones, a lower Karakaschi-ceras inostranzewi Subzone and an upper Saynoceras contestanum Subzone. The assemblages characterizing each of these biozones can be recognized throughout the Mediterranean region.