Petrology and mineral chemistry of peridotite nodules included in Tertiary basaltic rocks of northeast Brazil

The Tertiary volcanic suite in central Rio Grande do Norte and Northern Paraiba, which is composed of ankaratrites, basanites, and olivine basalts with basanitic affinities, forms plugs, necks, flows, and dikes that cut the Precambrian basement and Cretaceous sediments of the Apodi basin in a north-south trend. Xenocrysts of olivine, orthopyroxene, clinopyroxene, spinels, and granular and sheared spinel-Iherzolite and harzburgite nodules are found as inclusions in several necks and plugs. The entire xenolithic suite was derived from depths of approximately 64 to 55 km. The mineralogical and textural aspects of the nodules, as well as their mineral chemistry, are discussed.