Geological Study of Offshore Mud Volcanoes in the Southeast Caspian Sea

Mud volcanoes are one of the interesting phenomenons that many researchers in oil field, plate tectonics and geotourism consider the most. In this regard there are many studies in the other countries, especially those which have this phenomenon and published many articles. This article is the output of researches about anatomical characteristics of active, non active mud volcanoes and hidden diapir in the study region. Due to the subduction of Caspian Sea bed under the continental crust in southeast zone of Caspian Sea, there are a series of anticlines and synclinals which located in the west section NW-SE, in the middle section W-E and east section to Turkmanestan NE-SW. Due to the increase in the west thickness of Cheleken and Aghchagyl formations, Apsheron stage and Quaternary series that are calcareous, marl, clay and sandy and consist of gastropod and lamellibranches remains overlaying on each other conformity there are more mud volcanoes in west and southwest of Caspian Sea. There are 3 active, semi-active and few non active diapirs as well as a hidden one. Mud volcanoes at the southeast, semi- active and hidden diapir section of Caspian Sea, are almost in same direction with Caspian Sea fault. The seismic studies in the region show Plio-Quaternary compressive pressures and subsidence in the form of diapir is present on the surface. Anatomy of mud volcanoes of the region shows their history goes back to upper period Pliocene and scientifically their origin are tectonic-sedimentary.