The Kula Volcanic Field, western Turkey: the development of a Holocene alkali basalt province and the adjacent normal-faulting graben

Abstract

AbstractThe Kula province of Western Turkey provides an excellent example of an alkali basalt province in an area of active rifting. This paper establishes the relationship between the generation of the basalts and the extension of the region. The wide, shallow, terrestrial basin, formed by early extension, was subsequently cut through by narrow, fault-bounded grabens. The genesis of alkali basalt magmas began soon after the concentration of the extension into two grabens ˜2 Ma. The basalts, in the form of some 80 small cinder cones and associated lava flows and fields, have a total volume of 2.3 km3. This small volume reflects the small amount of extension in the region (β < 1.2 where β = final length of crust: initial length of crust).The intercalation of sediments and basalts in the Kula area enables the establishment of a relationship between the extensional activity and the generation of the basalts. This is demonstrable using radiometric and stratigraphic techniques, notably Ar-Ar dating of amphibole phenocrysts.