Sequence stratigraphy of the Berriassian-Lower Aptian deposits of West Siberia

The geological structure and conditions of formation of a Lower Cretaceous clinoform complex in West Siberia are examined based on sequence stratigraphy. The regional Berriasian-Hauterivian clinoforms are interpreted as third-order sequences, and their formation should be considered in terms of the Depositional Sequence III model. Productive beds of both shallow and deep marine as well as continental genesis formed mostly in a regressive basin and belong to the highstand systems tracts.     

Geologic structure and correlation of the Berriasian-Lower Aptian productive beds of the Gydan Peninsula (Russian Arctic)

We discuss the geologic structure of the Berriasian-Lower Aptian deposits of the Gydan Peninsula. Eight seismic sequences have been distinguished; most of them are associated with Lower Cretaceous regional clinoforms of West Siberia, their characteristics are given. A correlation of productive beds was based on the stratotype sections of the Yamal and Gydan Peninsulas as well as seismic and well data. A sequence stratigraphic model of the Berriasian-Lower Aptian complex is proposed.     

2D modeling of clastic accumulation in clinoforms under marine conditions

The 2D modeling of clastic accumulation in clinoforms under marine conditions is performed. For this purpose, two algorithms are used: the first, “geometric” one implies that the shapes of sedimentary bodies are defined by geometric methods; the second is a “diffusion” method, which is based on numerical solution of the diffusion equation. Modeling of the test section is made using different versions of these algorithms. Comparative analysis of modeling results suggests that the best fit with real sections is achieved by a combination of the geometric and diffusion algorithms.     

Patterns of the Distribution of Rare-Earth Elements in Waters of Mud Volcanoes

Doklady Earth Sciences - The original data on the distribution of rare-earth elements in waters of mud volcanoes of Sakhalin Island, Taman Peninsula, and Azerbaijan are presented. It has been shown...     

Computer simulation of Neocomian clinoform reservoirs in northern and arctic West Siberia

Neocomian reservoirs in the Mesozoic sedimentary cover of West Siberia have a complex geological structure. Their wedge-like (clinoform) geometry, with abrupt thickness changes and facies diversity (continental, shoreface, and pelagic deposits), causes difficulty in correlation between drilling- and seismics-based sand formations and clay caps. East-wedging (west-dipping) clinoforms consisting of interbedded clay and sand have the greatest reservoir potential in the West Siberian basin. Prediction of new oil and gas plays and their reservoir potential assessment require regional reconstructions in addition to local contour maps of individual zones and fields. However, the simulation technology which has been applied for years to Jurassic regional reservoirs is not fully applicable to the Neocomian clinoform sequences. Therefore we have adapted it correspondingly and suggest new tools to make due regard for the clinoform reservoir structure. The new approach has been tested through computing several structure and thickness contour maps of clinoform sequences for three largest regional Neocomian reservoirs (sub-Sarman, sub-Pim, and sub-Alymka) in northern and arctic West Siberia.     

Using Remote Sensing to Assess Russian Forest Fire Carbon Emissions

Russian boreal forests are subject to frequent wildfires. The resulting combustion of large amounts of biomass not only transforms forest vegetation, but it also creates significant carbon emissions that total, according to some authors, from 35–94 Mt C per year. These carbon emissions from forest fires should be considered an important part of the forest ecosystem carbon balance and a significant influence on atmospheric trace gases. In this paper we discuss a new method to assess forest fire damage. This method is based on using multi-spectral high-resolution satellite images, large-scale aerial photography, and declassified images obtained from the space-borne national security systems. A normalized difference vegetation index (NDVI) difference image was produced from pre- and post-fire satellite images from SPOT/HRVIR and RESURS-O/MSU-E images. A close relationship was found between values of the NDVI difference image and forest damage level. High-resolution satellite data and large-scale aerial-photos were used to calibrate the NDVI-derived forest damage map. The method was used for mapping of forest fire extent and damage and for estimating carbon emissions from burned forest areas.     

Deep structure of the Yuzhno-Sakhalinsk mud volcano: Results of multidisciplinary seismic surveys

The paper presents the results of multidisciplinary seismic surveys carried out by refraction and reflection methods for compressional and shear waves on Yuzhno-Sakhalinsk mud volcano. A large extinct (approximately 60–70 years ago) volcano was identified near the active volcano, and its structure was studied. It was found that the recognized intermediate fluid-bearing chambers correlate with the distinguished tectonic dislocations. A supposition was made that the mud volcanism is sequentially developed in the northeastern direction and related to the modern tectonics of the Central Sakhalin Fault.     

Geological history of Western Caucasus and adjacent foredeeps based on analysis of the regional balanced section

Using seismic evidence and other geological data, a balanced section has been built for the Tuapse foredeep-Western Caucasus-Western Kuban foredeep tectonic system. This section enabled us to restore the history of the region, from the Callovian time. It was suggested that, in the Callovian-Eocene, the western Caucasian basin existed in the form of a rift. The principal phase of rift inversion occurred in the Oligocene-Miocene, and in the Pliocene-Quaternary, it evolved into the orogeny phase. The extent of the Caucasus compression within the section area was more than 30 km.     

Modeling of the temperature regime of mud volcano gryphons

This paper is devoted to modeling of the dynamics of the temperature regime of mud volcano gryphons. The model is elaborated on the basis of a nonstationary equation of thermal conductivity with a convective component and describes well the observed regularities of thermal regime of South Sakhalin mud volcano gryphons. It is shown that anomalous changes in the temperature of the water-mud mixture after the Gornozavodsk and Nevelsk earthquakes in 2006–2007 are caused by variations in motion velocity of the mixture in the supply pipes of gryphons. It also has been shown that influx of deep geofluids cannot be considered as the main reason for thermal anomalies.