The evolution of slump-induced destruction of Kukuy Griva slope (Lake Baikal) revealed on the base of the data of seismic and acoustic surveys

As a result of careful interpretation of the data of recent seismo-acoustic surveys, two major seismic complexes were identified in the structure of the upper sedimentary section of the north-western slope of Kukuy Griva (ridge). They are composed of several inner seismo-facies, which are very characteristic and separated with well-expressed regional reflector. Seismic and acoustic data revealed evidences of numerous landslide processes which were different in age and peculiarities of manifestation. For the first time, detailed schemes of seismo-facies distribution are compiled for major seismic complexes at the area. The boundary between seismic complexes is dated as 150 thousands years. It is shown that sliding was more intensive during Late Pleistocene and Holocene, reflecting activation of tectonic movements in this part of Baikal rift system.     

Pleistocene sediments of the eastern barents sea (Central Deep and Murmansk Bank Areas): Communication 1. Occurrence conditions and main structural features

The areal geological-geophysical study of Quaternary sediments was carried out in two areas of the eastern Barents Sea (Central Deep and Murmansk Bank). This communication is mainly dedicated to the results of seismoacoustic investigations. It has been established that the Quaternary sequence unconformably overlying the pre-Cenozoic strata in the studied areas is as follows (from bottom to top): marine-glaciomarine Late Glacial-Holocene sediments, massive diamictons (the main part of the section), and glaciotectonites formed after the underlying Mesozoic unconsolidated sediments. The Pleistocene diamictons, origin of which is still debatable, are the main studied object. They constitute two seismostratigraphic complexes (SSC). According to the accepted stratigraphic subdivision, they are represented by the Upper Weichselian SSC III (Maximum Last Glaciation) and Lower Weichselian SSC V (Middle Weichselian SSC IV is eroded here). Complexes SSC V and SSC III composed of till overlie the older sediments with the exaration unconformity. Complex SSC V is preserved locally, while SSC III is characterized by the regional distribution. Complex SSC III is universally enveloped unconformably without erosional surface by an acoustically uniform thin-bedded member of Late Glacial-Holocene glaciomarine and marine sediments (SSC II+I). Unlike SSC V, SSC III demonstrates lateral heterogeneity in both studied areas consisting of two seismofacies, one of which forms very specific acoustically transparent bodies (ATBs). Sediments of SSC III avoided subsequent erosion. Therefore, their glacial nature is distinctly reflected in the complex distribution of thickness and peculiar morphology of corresponding bodies.     

Pleistocene sediments of the eastern Barents Sea (Central Deep and Murmansk Bank): Communication 2. Lithological composition and formation conditions

Llithology of massive diamictons was studied in two areas of the eastern Barents Sea using cores and geophysical data. These sediments dominate in the Pleistocene section as two seismostratigraphic complexes (SSC): Upper Weichselian (SSC III) and locally distributed Lower Weichselian (SSC V). Diamictons of these complexes represent tills produced by the geological activity of the Pleistocene Novaya Zemlya and Scandinavian ice sheets. The Upper Weichselian glacial sequence is laterally heterogeneous. It includes two seismic facies represented by ordinary (overconsolidated) tills (they also constitute SSC V) and a spacious moraine of the specific type with the normally consolidated sediments (they avoided compaction by the ice load) and certain lithological specifics. The last glacial sediments were formed in a specific subglacial setting similar to the sediments under fast ice streams of Antarctica. However, the specific features allow us to define these sediments as a new (Barents Sea) facies of tills related to zones of intense basal melting of glaciers.     

Cover of the Last Glaciation Deposits in the Eastern Barents Sea: Specificity of Composition,Thickness Distribution,Immensity, and Peculiarity of Structural Forms

Doklady Earth Sciences - Analysis of the data of seismoacoustic investigations and geotechnical drilling in the Eastern Barents Sea has shown the following. The cover of the Upper Weichselian...     

Main Features of the Structure,Lithological Composition,and Thickness of the Quaternary Deposits Cover in the Eastern Barents Sea

Doklady Earth Sciences - Analysis of the data of seismoacoustic investigations and engineering-geological drilling in the eastern Barents Sea has shown the following. The Quaternary sedimentary...