Abstract Cenozoic volcanic rocks in mainland Spain are located in the NE, east, SE and southern central parts of the peninsula (Fig. 17.1 ), and are mostly Neogene in age, although there was minor activity in both late Oligocene and Quaternary times (Fig. 17.2 ). Four main provinces can be recognized (Fig. 17.1 ): the SE volcanic province (SEVP, Cabo de Gata–Mazarrón–Cartagena); the Calatrava volcanic province in south central Spain (CVP); the NE volcanic province (NEVP, Ampurdán–Selva–Garrotxa); and the Gulf of Valencia volcanic province (GVVP), with both onshore and offshore emissions. The SEVP is the most heterogeneous and complex area with calc-alkaline (CA), high-K calc-alkaline (KCA), shoshonitic (SH) and ultrapotassic (UP) rocks, and alkaline basalts (AB). The CVP and NEVP are characterized by alkaline basalts, with occasional leucitites in the CVP. The GVVP contains CA rocks and AB, although the few available data on the offshore volcanism do not exclude a greater lithological variation. Other outcrops of igneous rocks also exist but are either volumetrically insignificant, incompletely studied or of unconstrained age: the Málaga tholeiitic dyke swarms in the western Betics ( Torres Roldán et al . 1986 ; Turner et al . 1999 ); the tholeiites of Alborán island ( Bellon & Brousse 1977 ; Aparicio et al . 1991 ); the volcaniclastic layer of the Lanaja– Peñalba area in the Ebro basin ( Odin et al . 1997 ); and the basaltic neck of Nuévalos in the Iberian Ranges ( Ancochea et al . 1987 ; Hoyos et al . 1998 ).