SEISMICITY of the AMUR and PRIMORYE, SAKHALIN, and the KURIL-OKHOTSK REGION in 2015

A review of the Amur and Primorye, Sakhalin, and the Kuril-Okhotsk region seismicity for 2015 is presented on the basis of data from the regional network of stationary seismic stations of the Sakhalin branch of the Geophysical Survey RAS with the involvement of data from adjacent seismological Russian and foreign agencies, as well as ten stations of the local network operating in the south Sakhalin. Parameters of 1643 seismic events have been determined, 126 of them are explosions. Focal mechanisms were calculated for 62 earthquakes. 48 earthquakes have shown a macroseismic effect. A map of the epicenters is presented, the distribution of the number N of crustal and deep-focus earthquakes by a magnitude, a total seismic energy ∑E for seismically active regions of three regions are given, in comparison with the average parameters N and ∑E for 20012014. For each region, an analysis of the parameters of the seismic regime in 2015 is given in comparison with long-term averages, the maximum and significant seismic events are described. The seismicity of the Priamurye and Primorye, Sakhalin, and the Kuril-Okhotsk region in 2015 can be characterized as a moderate one.

Russian Regional Carboniferous Stratigraphy

Several existing schemes for Carboniferous stratigraphy officially adopted in regions of the Russian Federation are summarized and discussed. These regions with different geological histories and distinct depositional settings include the Moscow Basin, the Urals, North Timan, Siberia, the Kuznetsk Basin, the Mongol-Okhotsk Region, and the Verkhoyansk-Okhotsk Region, and Kolyma-Omolon Region. Region. Broad correlations based on macro- and microfossils are possible between the regions, while all regional schemes are correlated to the official Russian General Stratigraphic Scheme for the Carboniferous, using zonations based on orthostratigraphic fossils. The Russian General Stratigraphic Scheme is correlated to the International Stratigraphic Scale using ammonoids, conodonts, foraminifers and palynomorphs.

Brachiopods of the Carboniferous-Permian Boundary Deposits of the Kubalakh Section (Lower Reaches of the Lena River, Northern Verkhoyanie)

The paper presents new data on the vertical distribution of brachiopods in the Carboniferous-Permian boundary deposits (the Kubalakh Formation) of the Kubalakh section (lower reaches of the Lena River). The deposits of the Kubalakh Formation are divided by the valley of the Kubalakh Creek into two outcrops, which are suggested to be considered as subformations. A brachiopod complex Jakutoproductus protoverkhoyanicus Kaschirzew, Verchojania abramovi Makoshin, Verchojania cf. monstrosus (Ganelin), Verchojania sp., Cancrinella? alazeica Zavodowsky, Tornquistia kolymensis Afanasjeva, Tornquistia sp., Rhynoleichus sp., Rhynchopora sp., characteristic of the Jakutoproductus protoverkhoyanicus Zone of the Kygyltasian Horizon of the Verkhoyanie is recognized in the Lower Kubalakh Subformation. A brachiopod complex Jakutoproductus verkhoyanicus (Fredericks), Jakutoproductus crassus Kaschirzew, Waagenoconcha aff. wimani (Fredericks), Orbiculoidea sp., Rhynchopora sp., characteristic of the Jakutoproductus verkhoyanicus Zone of the Khorokytian Horizon of the Verkhoyanie is recognized in the Upper Kubalakh Subformation. Based on the data presented, the Carboniferous-Permian boundary should be drawn within the Kubalakh Formation, rather than at the base of the Tuora-Sis formation, as is was accepted on the basis of the latest Unified Regional Scheme of Permian Deposits in the Verkhoyansk-Okhotsk region.

SUBMARINE HYDROGEOLOGICAL STRUCTURES AND UNDERGROUND WATERS OF THE SEA OF OKHOTSK REGION

The results of multi-year regional geological, geophysical, oil, and hydrogeological exploration related to the study of seas and oceans were used to characterize the submarine hydrogeological structures of the Sea of Okhotsk region - hydrogeological massifs, artesian and volcanogenic basins. The hydrogeological stratification of the geological cross-section was performed, according to which five Cenozoic aquifer systems were distinguished in the artesian basins. The chemical composition of submarine groundwater was characterized, whose mineralization decreases with depth from 27–30 g/dm3 to14–20 g/dm3. Gases (mainly methane) and thermal waters forming orebodies of metallic sulfides and non-metallic minerals are discharged into the bottom sea waters along zones of tectonic faults.