Estudio petrográfico de las rocas de los dólmenes Aizkomendi y Sorginetxe (Álava)

Abstract

In this work the lithologic types and the origin of the large rock slabs that form two of the largest megalithic monuments in the eastern Plain of Araba, the Aizkomendi and Sorginetxe dolmens, are established. the constituent lithologic types have been distinguished through a detailed petrographic study and a comparison with characteristic rock formations cropping out around the megalith locations. the study concludes that the Aizkomendi and Sorginetxe dolmens are mainly made up of two different formations of Paleocene carbonate rocks. Additionally, the Aizkomendi dolmen contains a slab from Albian quarzarenites (balmaseda fm), exposed along the southern side of the Aizkorri-Aratz ridge. these data demonstrate that the construction of the Aizkomendi and Sorginetxe dolmens was carried out mainly using rock pieces from the northern edge of the Entzia and Iturrieta ridges.