Journal of Volcanology and Geothermal Research: Intracanyon basalt lavas of the Debed River, northern Armenia

These lavas are part of a Pliocene-Pleistocene continental flood basalt province in the South Caucasus region. The province covers an area of approximately 15,000 square kilometers and has a volume of around 2,250 cubic kilometers. It is the smallest and youngest continental flood basalt province in the world. The basalt lavas in the Debed River canyon are characterized by three distinct morphological types. The lower and middle lavas are composed of basal pillow basalts and hyaloclastites, which are overlain by columnar-jointed pahoehoe sheet flows. The upper lavas are composed of slabby pahoehoe and rubbly pahoehoe flows. These lavas show evidence of damming of river drainage, similar to many other continental flood basalt provinces, such as those in Scotland, Ireland, and Iceland. Additionally, there is evidence of syn-volcanic faulting of the early lavas. The South Caucasus basalt province is closely similar in major features to the Late Miocene Altos de Jalisco continental flood basalt province in the western Trans-Mexican Volcanic Belt. Both provinces formed during lithospheric pull-apart and transtensional faulting. The broader significance of these provinces is in showing that flood basalt size distribution is a continuum without natural breaks, with implications for geodynamic models. The Debed River canyon basalts are part of a larger geological feature that extends into the Gegham Uplands and the Hrazdan River basin in Armenia. The age of the basalts is estimated to be between 3.25 and 2.05 million years, during the Late Pliocene to Early Pleistocene period. This time frame is consistent with the formation of other continental flood basalt provinces around the world. The study of these basalts provides valuable insights into the geological history of the region and the processes that shaped the Earth's surface.