Peculiarities of the rare-earth element distribution in the modern bottom sediments of the White Sea and the lower reaches of the Severnaya Dvina River

The study of the rare-earth element (REE) systematics in the modern bottom sediments of the White Sea and the lower reaches of the Severnaya Dvina River showed that they were derived by the simple mixing of the detrital material from two geochemically contrasting provenances: the Kola-Karelian geoblock almost completely consisting of Archean rocks and the northwestern Mezen syneclise made up of the Upper Vendian, Paleozoic, and Mesozoic rocks. This is best manifested by the changes in ?_Nd(0). In terms of the Gd_N/Yb_N and Eu/Eu*, most of the studied samples are comparable with the Post-Archean craton complexes, some of which resemble the average composition of the Archean mudstone. Based on the ΣREE and La_N/Yb_N, the modern bottom sediments are subdivided into two groups: (1) those close to basalts and granites and (2) those approximating common sedimentary rocks. From the lower reaches of the Pinega River to the Tersky coast, the maximal average (La/Yb)_RPSC, (Gd/Yb)_RPSC, La_N/Yb_N, and Gd_N/Yb_N ratios were determined in the samples taken at the boundary of Dvina Bay with the Basin, i.e., in the sediments with the highest content of the pelitic component. In general, the geochemical composition of the modern bottom sediments of almost the entire White Sea area was defined by input of the eroded products of the mature continental crust with the Severnaya Dvina River, the main river of the region. Such a setting, when the formation of the sediments in a peri- or intracontinental marine basin is controlled by one large river system, presumably may be propagated to the sedimentation in the Laptev Sea, the eastern Kara Sea, the Bay of Bengal, and other basins.     

Dynamics of the main components of fluxes of sedimentary matter in the White Sea

Doklady Earth Sciences - The results of long-term investigations in a small sea of the Arctic Ocean served as a basis for revealing new regularities characteristic of the sedimentary process in the...     

Sedimentogenesis in the White Sea: Vertical Fluxes of Suspended Particulate Matter and Absolute Masses of Bottom Sediments

Oceanology - A new approach has been applied to studying marine sedimentation using dispersed sedimentary material in sediment traps compared to the surface layer of bottom sediments. Based on...     

Studies of Sedimentary Matter Fluxes along a Long-Term Transoceanic Transect in the North Atlantic and Arctic Interaction Area

Oceanology - New data are presented on sedimentary matter fluxes and its main components along a meridional transect (59°30′ N) in the North Atlantic under the effect of multidirectional...     

Dispersed Sedimentary Matter of the Barents Sea

Oceanology - The article presents the results of studying the distribution and composition of dispersed sedimentary matter (suspended particulate matter, SPM) in the Barents Sea water column. The...     

Distribution of Suspended Particulate Matter in the Caspian Sea

The distribution of suspended particulate matter (SPM) and chlorophyll a in the Caspian Sea water column from April to November in 2008–2016 is analyzed. It is shown that the spatiotemporal variability of SPM concentration is defined by its sources, especially by the autochthonous (primary production) and allochthonous (particulate river runoff, aerosols) components. The effect of marginal filters of rivers on the volume of coming allochthonous SPM is considered. It is revealed that chlorophyll a is a reliable marker of the autochthonous component of SPM and biogenic sedimentation conditions. The stable vertical stratification defines the distribution of allochthonous and autochthonous SPM in the water column. Vertical profiles of these SPM components in the active layer (its thickness is usually up to ~60 m, more rarely to ~100 m) of the sea are similar in April and October-November and differ much in May-September.     

Distribution and composition of suspended particulate matter in the Atlantic Ocean: Direct measurements and satellite data

The main purpose of this work is to study the real distribution and spatial–temporal variations of suspended particulate matter and its main components in surface waters of the Atlantic Ocean on the basis of direct and satellite measurements for development of new and perfection of available algorithms for converting satellite data. The distribution fields of suspended particulate matter were calculated and plotted for the entire Atlantic Ocean. It is established that its distribution in the open ocean is subordinate to the latitudinal climatic zonality. The areas with maximum concentrations form latitudinal belts corresponding to high-productivity eutrophic and mesotrophic waters of the northern and southern temperate humid belts and with the equatorial humid zone. Phytoplankton, the productivity of which depends primarily on the climatic zonality, is the main producer of suspended particulate matter in the surface water layer.     

Determination of the concentration of mineral particles and suspended organic substance based on their spectral absorption

A method to determine the concentrations of the particulate mineral matter (C _PMM) and the particulate organic matter (C _POM) is suggested. The values of C _PMM and C _POM are calculated from the measurements of the spectral coefficients of the light absorption a _POM(440) and a _PMM(750) using empirical equations. The latter have been obtained by comparing the concentrations of the suspended solids measured by means of the gravimetric method with the spectral values of the optical density of the suspended matter settled on membrane filters. The data used are typical of the coastal waters of inland and marginal seas and the open ocean and cover the range of three and two orders of magnitude for the concentrations of C _PMM and C _POM, respectively.     

Specific features of the distribution of trace and rare earth elements in recent bottom sediments in the lower course of the Severnaya Dvina River and White Sea

The paper discusses results of the lithogeochemical examination of recent bottom sediments in the lower course of the Severnaya Dvina River and White Sea. It has been established that the average concentration of several trace elements (Hf, Sc, Co, Y, Ni, V, Cr, Zr, Ba, and others) therein correlates with the content of the silt-pelite fraction. Maximal concentrations of the majority of above elements are confined to the silty-clayey sediments at the Basin/Dvina Bay boundary. They localized near the coastal zone only for some clastophile (Zr, Cr, and others). Typical values of the hydrolyzate module, chemical index of alteration, and Al₂O₃/SiO₂ ratio in the aleuropelitic and pelitic sediments of the Severnaya Dvina River delta, Dvina Bay, and the Dvina Bay Basin boundary suggest that these sediments are confined to sufficiently cold climate settings. Data points of sediment composition in discriminant paleotectonic diagrams are scattered over a large field probably due to high contents of the weakly weathered plagioclases, micas, and amphiboles, as well as the hydrogenic process promoting the accumulation of Fe and Mn. The PAAS-normalized spectra of rare earth elements (REE) in bottom sediments of the Pinega and Severnaya Dvina rivers, marginal filter of the latter river, Dvina Bay, and the Dvina Bay Basin boundary are similar to the REE distribution in clayey rocks of the ancient platform cover (except for a slight positive Eu anomaly). The REE systematics and distribution pattern of compositional data points of recent bottom sediments in the Gd_N/Yb_N-Eu/Eu* and Eu/Eu*-Cr/Th diagrams and values of several indicator ratios of trace elements suggest that the studied rocks were formed by the mixing of clastic materials from geochemically contrast provenances: northwestern provenance (Kola-Karelia geoblock), which is mostly composed of the Archean and Early Proterozoic crystalline complexes, and the southeastern provenance (northwestern periphery of the Mezen syncline), which is almost totally composed of Phanerozoic sedimentary rocks. The latter provenance likely played a crucial role in the geochemical signature of recent bottom sediments over a significant area of the White Sea.     

Concentration,Composition, and Fluxes of Dispersed Sedimentary Material in the Snow and Ice Cover of the Polar Arctic

Oceanology - Abstract—Dispersed sedimentary material in the snow and ice cover is directly determined near the North Pole. The composition of sedimentary material in the snow and ice cover...