Mud Diapirism on the Gorgan, North Iran (original) (raw)
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Mud Diapirism on the Makran, Iran: Case Study on the Napag Mud Volcano
Open Journal of Geology, 2015
The Napag is the biggest Mud Volcano at Makran in Iran. The main aim of this research is the investigation of geologic setting and geographic situation of Napag Mud Volcano as a well-known mud diapir at Makran on the south eastern margin of Iran. The Napag Mud Volcano has been formed during quaternary of as a conical hill on the flat plain in coastal region Oman Sea. There are badlands area and several mud volcanoes that they have been triggered by longitudinal normal faults. This normal faults have been developed in neotectonic regime by the roll-back of oceanic lithosphere (beneath of Oman Sea). Finally, the main characteristics of the Napag mud diapir are presented.
2017
Mud volcanoes (MV) have been known since the 19th century. Their surface morphologies have been extensively studied but the issue of underground structure and mud generation mechanisms could only be investigated recently with the use of 3-D seismic in particular. The South Caspian Basin (SCB) and the Lower Kura Basin, onshore Azerbaijan, have the densest known distribution of MV in the world. Three-dimensional (3D) seismic data acquired by oil and gas companies in the offshore domain offer the opportunity to understand possible mechanisms of mud generation and MV systems formation. The offshore 3-D seismic survey of the Absheron anticline shows two MVs with very different morphologies. The smaller one has a well imaged root system that shows a direct link with the regional source rock, the Maykop Formation. The emplacement of this MV is related to a thrust rooting in the source rock. It creates a truncated small anticline structure as a result of mud expulsion. A rim syncline shows the collapse of strata into the former mud chamber. The extrusion cone is now buried bellow 5 km of sediments. The larger volcano, still active, is located on the anticline crest; its underground structure is poorly imaged due to the presence of gas. Two overpressured intervals are known in the area and could have sourced the mud: the regional source rock (Maykop Fm.) buried at 6.5 km; or the Upper Surakhany Suite at 2.5 km. Seafloor bathymetry shows a 4.5 km-diameter mud shield with 5 mud-pies, 300 m to 1 km in diameter, distributed at its surface. The mud shield is surrounded by a moat and ridge; the latter has been breached on various points and a 10 km long mud flow emanates from the western breach. On seismic sections, compressive structures and other mud flows can be noticed. Based on a comparison of these MVs with already studied structures of the SCB and field observations of onshore MVs, we propose the following model for the initiation and subsequent evolution of the Absheron MV system. Overpressure accumulates at the crest of anticlines causing pervasive hydrofracturing that propagates upward. Mud forms when the advective column of mixed particles and fluids reaches the seafloor. A higher sedimentation rate or a lowering in fluid advection allows the proto-mud chamber to be buried, slowly increasing mud pressure. The input of fluids into the mud chamber may help to sustain this mud pressure and to decrease mud density. When overpressure is too high or mud is too light, the fluidized material is extruded through a combination of hydrofracturing and passive roof collapse. This qualitative model will be integrated to a geomechanical model along with results from mechanical measurements on mud samples from the Absheron MV. Other models could be imagined by exploring other possibilities as processes related to clay dehydration. Biostratigraphic analysis of the sediment cores from Absheron will constrain the source of the mud.
AIP Conference Proceedings, 2006
Mud volcanoes of Azerbaijan and the South-Caspian Basin (SCB) are closely related to tectonic processes in the basin and the orogenic system of Greater and Lesser Caucasus. The maximum density of the mud volcanoes in Azerbaijan and the SCB is observed in the Shamakha-Gobustan zone. The joint manifestation of the mud volcanism and shallow earthquakes shows the intensive processes in sedimentary strata causing mechanical instability as well as the formation of seal failure of the sedimentary rocks. The statistic processing of 150-year eruptions of the mud volcanoes and astronomic periodicity of mutual location of the Earth, Sun and the Moon allowed establishing the closest relation between these phenomena and the important regularity. About 60% of all (over 200) eruptions take place during new moon or full moon. On this base the forecasting on volcanic activity is made. The results of the study of 300 mud volcanoes from various parts of the world in connection with 11-year cycle of the sun activity had revealed a good agreement between the mud volcanic periodicity and the sun activation. The recent sun activity (2000-2001) had provoked an activation of four mud volcanoes of the western flank of SCB during seven months.
Relics of mud volcanoes in the sedimentary cover of the South Caspian Basin
Lithology and Mineral Resources, 2015
The paper is devoted to one of the phenomena in young sedimentary basins related to their dise quilibrium and the consequent formation of subvertical sedimentary structures. We propose the term "sedi mentary plume" for such structures. The paper presents descriptions of the probable forms of sedimentary plumes, as well as their reflection in seismic data, age, stratigraphic features, and formation conditions. Their formation is likely related to processes of the deconsolidation of sedimentary piles because of phase transi tions. According to this concept, the formation of hydrocarbon pools is attributed to a series of sequential processes including the convective dislocation of matter along with the floating of unconsolidated clay bodies, phase transitions and conjugated processes of the HC generation, migration, and accumulation.
Geografiska Annaler Series A-physical Geography, 2016
Mud volcanoes are geomorphological phenomena and there is a limited volume of knowledge about them. Output of a composition of water, mud, and gas forms the mud volcano phenomenon. Geographical distribution of mud volcanoes indicates their relationship with pressured, rapid and thick sedimentation, which is seen in both tectonically active and inactive zones. Naftlige mud volcano is located in the southwest of the Caspian Sea and west of Gomishan Wetland in Golestan Province, Iran. Since no study has ever been conducted with a specific focus on mud volcanoes, field and laboratory studies were carried out for the first time to overcome the shortage of library resources. The objective was to determine the composition of emerging mud and study its morphometric and geomorphic features so that there would be a method for identifying and introducing some unknown aspects of this mud volcano. Therefore, three samples of this mud volcano which were taken on 27 Apr., 2012 were tested and analyzed using X-ray diffraction and X-ray fluorescence techniques to determine the mineral and chemical composition. The results of this analysis showed that, in these three samples, silicon oxide with the chemical formula SiO 2 had 40.88% volatile materials, 19.15% H 2 O Loss on Ignition (LOI) and 13.97% calcium oxide. Quartz, calcite and albite formed the three main phases of minerals.
Environmental Geology, 2004
The South Caspian sedimentary basin is a unique area with thick Mesozoic-Cenozoic sediments (up to 30-32 km) characterized by an extremely high fluid generation potential. The large amount of active mud volcanoes and the volumes of their gas emissions prove the vast scale of fluid generation. Onshore and offshore mud volcanoes annually erupt more than 10 9 cubic meters of gases consisting of CH 4 (79-98%
Mud Volcanoes in an Active Fore-Arc Setting: A Case Study from the Makran Coastal Belt, SW Pakistan
The Makran coastal belt is over 1000 km long stretching from Iran to east of Karachi in Pakistan. A major active subduction zone known as Makran subduction zone defi ned by the under thrusting of the Arabian plate beneath the Eurasian plate runs parallel to the coastline. The subduction zone is associated with a thick accretionary sedimentary wedge deposited in an active fore-arc basin containing very thick detrital sediments contributed by the accretion of the subducting plate since Late Eocene time. The sediments in the fore-arc basin are fi ne-grained usually of clay size fraction deposited in highly fl uidized conditions trapping methane gas. The fl uidized mud diapirically moves upward along weak zones as mud volcanoes due to high sedimentation rates and escaping gas pressure piercing through the overlying sediment layers. The development of mud volcanoes shows a close relationship between the sedimentation rates, gas escape from sediments and tectonic activity. Mud volcanoes are found in abundance both onshore and offshore of the Makran Coast. Most of the onshore mud volcanoes are associated with active fault zones and are believed to be triggered by tectonic activity. Located in the hanging wall of an active subduction zone, the region is seismically highly active and occur
A review on mud volcanoes and petroleum potential of the South Caspian Basin
International Journal of Earth Sciences Knowledge and Applications, 2024
There is a close relationship between mud volcanoes (MVs) and oil and gas fields. The close relationship between MVs and petroleum systems has been proven in many studies. Most of the extensive information published on the South Caspian Depression and its hydrocarbon resources is only available in the Russian language, and commonly in books and journals that are not readily available in the open-acces. Therefore, this study reviews the structural control of MVs in the petroleum system of the South Caspian basin. It presents the results of surveys to study hydrocarbon systems of the territory using the solving oil and gas geology issues. MVs have become evident that a sedimentary complex of depositions allow us to assess the role of fluid dynamic processes in forming and placing hydrocarbon deposits in the South Caspian Basin. Keywords: degassing of the Earth’s crust, mud volcano, mud volcanism, petroleum system, South Caspian Basin
Mud Volcanoes of Azerbaijan-Windows to the Subsurface
Mud volcanoes are prominent geological features of Azerbaijan. Tectonic forces control their occurrences in regions with over-pressured subsurface sediments as mud volcanoes are closely linked to fault systems. The mud of volcano cones contains numerous ejected rock fragments, which we use to identify the depths from which the mud has been transported. Organic geochemical, organic petrographical and mircopalaeontological investigations have been performed on selected samples of 19 mud volcanoes. The amounts of extractable hydrocarbons in relation to organic carbon contents indicate that most of the sediment samples are impregnated by migrated hydrocarbons. Hydrogen and oxygen indices derived from RockEval pyrolyses indicate that the organic matter of the sediments consist mostly of mixtures of Type II and III kerogens. All extracted hydrocarbons have been affected by secondary alterations that most likely involved biodegradation as the normal alkanes have been removed to a large ext...