Determining the elastic moduli of the third order for sedimentary rocks based on well-logging data

The method of determining the values of elastic moduli of the third order of sedimentary series of rocks is developed based on a complex of well-logging data. The calculation algorithm is based on the theory of elastic wave propagation in deformed solids, seismic-geological modeling, and the cluster analysis of well data on artificial neural networks. The elastic moduli of sedimentary series of rocks of oil- and gas-bearing structures of the Gunashli of the South Caspian Basin (SCB) are determined using the offered method. The numerical values of Poisson’s ratio are also determined for these rocks. The inaccuracies of the results obtained within the simplified theories are revealed in this example without considering the current geodynamic changes.     

GPS-based crustal deformations in Azerbaijan and their influence on seismicity and mud volcanism

Using Shen’s method (Shen et al., 1996), deformations of the Earth’s crust in Azerbaijan were studied based on GPS measurements. For estimating the rate of deformation, we used the field of velocity vectors for Azerbaijan, Iran, Georgia, and Armenia that were derived from GPS measurements during 1998–2012. It is established that compression is observable along the Greater Caucasus, in Gobustan, the Kura depression, Nakhchyvan Autonomous Republic, and adjacent areas of Iran. The axes of compression/contraction of the crust in the Greater Caucasus region are oriented in the S-NE direction. The maximum strain rate (approximately 200 × 10^?9 per annum) is documented in the zone of mud volcanism at the SHIK site (Shykhlar), which is marked by a sharp change in the direction of the compression axes (SW-NE). It is revealed that the deformation field also includes the zones where strain rates are very low approximating 5 × 10^?9 per annum. These zones include the Caspian-Guba and northern Gobustan areas, characterized by extensive development of mud volcanism. The extension zones are confined to the Lesser Caucasus and are revealed in the Gedabek (GEDA) and Shusha (SHOU) areas, as well as in the zone located between the DAMO and PIRM sites (Iran), where the deformation rate amounts to 100 × 10^?9 per annum. It is concluded that the predominant factor responsible for the eruption of mud volcanoes is the intensity of gas-generation processes in the earth’s interior, while deformation processes play the role of a trigger. The zone of the epicenters of strong earthquakes is correlated to the gradient zone in the crustal strain rates.     

Collision with meteoroids as one of the possible mechanisms for the splitting of cometary nuclei

Results are presented of a statistical analysis of dynamic parameters for 114 comets with split nuclei. A list of the objects includes actually split comets, fragments of cometary pairs, lost comets with designation D, and comets with large-scale atmospheric features. Some aspects of the hypothesis that splitting is caused by collisions of cometary nuclei with meteoroid swarms are investigated. To verify the hypothesis, an analysis is conducted of the positions of split comets’ orbits relative to 58 meteor streams from Cook’s catalogue. The calculations give the number (N) of orbital nodes of split comets relative to the plane of each swarm within a distance of 0.001, 0.005, 0.01, 0.05, and 0.1 AU from each swarm. A special algorithm is proposed for determining the degree of redundancy of N by finding the expected value and dispersion for the number of the nodes. The comparison of N with the expected value, together with the consideration of the dispersion, reveals a redundancy of N in 29 cases. Therefore, collisions of comets with meteoroid swarms can be considered as one of the possible causes of comet splitting. A similar testing is conducted for the asteroid belt and Kuiper belt as potential sources of a vast number of sporadic meteoroids. Based on the results of the calculations, the former may be considered as the most effective region of splitting of periodic comets.     

In situ cone penetration tests at the active Dashgil mud volcano,Azerbaijan: Evidence for excess fluid pressure,updoming, and possible future violent eruption

Active mud volcanism is a global phenomenon that represents a natural hazard by self-igniting eruptions and the continuous emission of methane gas in both marine and continental settings. Mud domes are often found in compressional tectonic settings such as the Caucasus orogenic wedge. Dashgil mud volcano, the most prominent of >200 features in Azerbaijan, has erupted vigorously in historic times. For several years, we have observed variations in the activity of Dashgil dome, including transients in methane flux, build-up of extrusive mud cones on the main feature, and flexural polygonal cracks adjacent to the main crater lake and new mud cones. In spring 2007, we carried out in situ CPTU (Cone Penetration Testing with Pore Pressure measurement) experiments in the crestal area of Dashgil. Our data suggest that the central portion of the crater lake, which hosts the conduit for gas (and possible mud) ascent, shows both low sediment shear strength (<5–20 kPa) and excess pore fluid pressures between 15 and 30 kPa supra-hydrostatic at 1 m sub-bottom depth. In situ cone resistance as a measure for undrained shear strength is as low as 150 kPa in the conduit, whereas the mud is found rather stiff in all other testing locations (300–700 kPa, probably a result of deeply buried shales of the Maikop formation parts of which now liquefy and ascend). Pore pressure is low in the centre of the conduit, probably because of rapidly migrating gas. It increases to 30 kPa at the lake bottom and deep flank, then decreases upslope on the lake flank, and reaches hydrostatic values at the crater rim. From the overpressured region beneath the fluid-filled crest of Dashgil dome, combined with the other observations, we suspect to currently witness an ongoing period of updoming. The presence of sintered mudstones from explosive eruptions in 1908 and 1928 (and most likely before) suggests that a similar violent activity may occur in the near future.     

When mud volcanoes sleep: Insight from seep geochemistry at the Dashgil mud volcano,Azerbaijan

The worlds >1500 mud volcanoes are normally in a dormant stage due to the short duration of eruptions. Their dormant stage activity is often characterized by vigorous seepage of water, gas, and petroleum. However, the source of the fluids and the fluid–rock interactions within the mud volcano conduit remain poorly understood. In order to investigate this type of activity, we have combined satellite images with fieldwork and extensive sampling of water and gas at seeping gryphons, pools and salsa lakes at the Dashgil mud volcano in Azerbaijan. We find that caldera collapse faults and E–W oriented faults determine the location of the seeps. The seeping gas is dominated by methane (94.9–99.6%), with a δ¹³C (‰ V-PDB) in the −43.9 to −40.4‰ range, consistent throughout the 12 analysed seeps. Ethane and carbon dioxide occur in minor amounts. Seventeen samples of seeping water show a wide range in solute content and isotopic composition. Pools and salsa lakes have the highest salinities (up to 101,043 ppm Cl) and the lowest δ¹⁸O (‰ V-SMOW) values (1–4‰). The mud-rich gryphons have low salinities (<18,000 ppm Cl) and are enriched in ¹⁸O (δ¹⁸O = 4–6‰).     

Mud volcanic natural phenomena in the South Caspian Basin: geology,fluid dynamics and environmental impact

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 10⁹ cubic meters of gases consisting of CH₄ (79–98%), and a small admixture of C₂H₆, C₃H₈, C₄H₁₀, C₅H₁₂, CO₂, N, H₂S, Ar, He. Mud volcanism is closely connected to the processes occurring in the South Caspian depression, its seismicity, fluctuations of the Caspian Sea level, solar activity and hydrocarbon generation.The large accumulations of gas hydrates are confined to the bottom sediments of the Caspian Sea, mud volcanoes crater fields (interval 0–0.4 m, sea depth 480 m) and to the volcanoes body at the depth of 480–800 from the sea bottom. Resources of HC gases in hydrates saturated sediments up to a depth of 100 m and are estimated at 0.2×10¹⁵–8×10¹⁵ m³. The amount of HC gases concentrated in them is 10¹¹–10¹² m³.The Caspian Sea, being an inland closed basin is very sensitive to climatic and tectonic events expressed in sea level fluctuations. During regressive stages as a result of sea level fall and the reducing of hydrostatic pressure the decomposition of gas hydrates and the releasing of a great volume of HC gases consisting mainly of methane are observed.From the data of deep drilling, seismoacoustics, and deep seismic mud volcanic activity in the South Caspian Basin started in the Lower Miocene. Activity reached its highest intensity at the boundary between the Miocene and Pliocene and was associated with dramatic Caspian Sea level fall in the Lower Pliocene of up to 600 m, which led to the isolation of the PaleoCaspian from the Eastern ParaTethys. Catastrophic reduction of PaleoCaspian size combined with the increasing scale of mud volcanic activity caused the oversaturation and intoxication of water by methane and led to the mass extinction of mollusks, fishes and other groups of sea inhabitants. In the Upper Pliocene and Quaternary mud volcanism occurred under the conditions of a semi-closed sea periodically connected with the Pontian and Mediterranean Basins. Those stages of Caspian Sea history are characterized by the revival of the Caspian organic world.Monitoring of mud volcanoes onshore of the South Caspian demonstrated that any eruption is predicted by seismic activation in the region (South-Eastern Caucasus) and intensive fluid dynamics on the volcanoes.     

On the Existence of Long-Period Comet Families of the Giant Planets

Astronomy Letters - We analyze the minimum orbital intersection distances (MOIDs) for a sample of long-period comets (1360) and the giant planets of the Solar System. Our calculations have revealed...     

Geochemical Characteristics of Organic Matter from Maikop Rocks of Eastern Azerbaijan

Based on investigation of more than 170 samples taken from natural outcrops of the Maikop Formation (Oligocene–Lower Miocene) in eastern Azerbaijan, the genetic hydrocarbon potential and the organic matter (OM) maturity of these rocks were estimated. In the study region, sedimentary rocks of this formation were deposited under reductive or weakly oxidative conditions. Possessing a relatively high (1.9%, on the average) content of organic matter of a mixed (continental–marine) OM, these rocks are able to generate both liquid and gaseous hydrocarbons under favorable conditions. Contributions of both the continental and marine components to the total organic carbon (TOC) varied in time and space. The upper and lower subformations of the Maikop Formation differ in the qualitative and quantitative compositions of OM. Oligocene rocks have a relatively lower OM content and are characterized by better oil-generating properties, as compared to lower Miocene rocks.     

On the relationship of long-period comets to known and unknown planets

Statistical aspects of the question of the dynamical relationship of long-period comets to giant planets (Saturn, Uranus, Neptune), dwarf planets (Pluto, 2003 EL₆₁, 2003 UB₃₁₃), and five hypothetical planets are investigated. Data for 859 and 888 comets (2005, 2006) with periods P > 200 years are used in the statistics. No comets of the Kreutz, Marsden, Kracht, and Meyer groups are considered. The minimum interorbital distances of comets from the listed planetary bodies are mainly analyzed. Effects testifying to the kinematical relationship of some of the comets to planets have been established by testing the cometary data relative to 67 planes. The distribution of the perihelia of long-period comets is also discussed.     

Test of the Hypothesis for an Unknown Distant Massive Planet in the Solar System Applying Tisserand’s Criterion to a System of Long-Period Comets

Earth, Moon, and Planets - One meter class telescopes could bring important contributions in the acquisition of lightcurves of near earth asteroids (NEAs), based on which rotations and other...