Compositions of paleosols from the Salarevo Formation, Sukhona River valley (Severnaya Dvina basin)

Paleosols crop out in the Sukhona River valley as several members up to 10 m thick embedded into the Salarevo Formation sediments. Principal characteristics of the paleosols include a dense network of root channels, indications of eluvial gley alteration, redistribution and formation of secondary carbonates represented by several generations, and formation of block-prismatic soil structure with specific clayey films at structural jointing faces. The paleosols are divided into a number of genetically interrelated horizons (from top to bottom): presumably organogenic accumulation (AElg), eluvial gley horizon (Elg), illuvial horizons (B1 and B2), illuvial gley horizon (Bg), and transitional horizons (ElBg and BElg). The paleosols formed under conditions of a semiarid climate with sharp seasonal or secular and multisecular oscillations of atmospheric precipitation. Such soils point to specific ecological environments existed in the northern semiarid belt of the Earth before the greatest (in Phanerozoic) biospheric crisis at the Permian-Triassic boundary.

Illustrations of manganese nodules dredged from the Upper Jarvis Inlet

Manganese-iron oxide concretions are presently forming on Patrick Sill in upper Jervis Inlet. The marine geology of Patrick Sill and the adjoining basins (Queen's Reach and Princess Royal Reach) was studied to define the environment in which the concretions form. The river at the inlet head is the principal source of sediment to the upper basin. The average grain size of surficial bottom sediments within this basin decreases uniformly with distance from the source. Patrick Sill separates the upper from the lower basin. The sediment distribution pattern within the lower basin differs markedly from the upper basin as there is no dominant source of material but rather many localized sources. Abundant shallow marine faunal remains recovered in deep water sediment samples indicate that sediments deposited as deltas off river and stream mouths periodically slump to the basin floors. Geologic and optical turbidity information for the upper basin can best be explained by slumping from the delta at the inlet head with the initiation of turbidity or density currents. Patrick Sill appears to create a downstream barrier to this flow. The mineralogy of the bottom sediments indicates derivation from a granitic terrain. If this is so, the sediments presently being deposited in both basins are reworked glacial materials initially derived by glacial action outside the present watershed. Upper Jervis Inlet is mapped as lying within a roof pendant of pre-batholithic rocks, principally slates. Patrick Sill is thought to be a bedrock feature mantled with Pleistocene glacial material. The accumulation rate of recent sediments on the sill is low especially in the V-notch or medial depression. The manganese-iron oxide concretions are forming within the depression and apparently nowhere else in the study area. Also forming within the depression are crusts of iron oxide and what are tentatively identified as glauconite-montmorillonoid pellets. The concretions are thought to form by precipitation of manganese-iron oxides on pebbles and cobbles lying at the sediment water interface. The oxide materials are mobile in the reducing environment of the underlying clayey-sand sediment but precipitate on contact with the oxygenating environment of the surficial sediments. The iron crusts are thought to be forming on extensive rocky surfaces above the sediment water interface. The overall appearance and evidence of rapid formation of the crusts suggests they formed from a gel in sea water. Reserves of manganese-iron concretions on Patrick Sill were estimated to be 117 metric tons. Other deposits of concretions have recently been found in other inlets and in the Strait of Georgia but, to date, the extent of these has not been determined.

Annual variations in composition of the North Dvina River water

New data on elemental composition of particulate matter from the North Dvina River are presented. In May (period of snowmelt flood) it is similar to the upper layer of the continental crust due to active erosion of crust material in the catchment area. In August (summer low water period) impact of biogenic components increases and elevated concentrations of Cd, Sb, Mn, Zn, Pb, and Cu are observed. At other seasons no significant increase in heavy and rare earth element concentrations is observed.

Dinoflagellate cysts analyses from sediment cores of the Po River discharge plume over the last two centuries

To obtain insight into the natural and/or human-induced changes in the trophic state of the distal portion of the Po River discharge plume over the last two centuries, high temporal resolution dinoflagellate cyst records were established at three sites. Cyst production rates appear to reflect the natural variability in the river's discharge, whereas cyst associations reflect the trophic state of the upper waters, which in turn can be related to agricultural development. The increased abundances of Lingulodinium machaerophorum and Stelladinium stellatum found as early as 1890 and 1920 correspond to the beginning of the industrial revolution in Italy and the first chemical production and dispersion of ammonia throughout Europe. After 1955, the increased abundances of these species and of Polykrikos schwartzii, Brigantedinium spp. and Pentapharsodinium dalei correspond to agriculturally induced alterations of the hypertrophic conditions. A slight improvement in water quality can be observed from 1987 onward.

Proglacial river dataset from the Akuliarusiarsuup Kuua River northern tributary, Southwest Greenland, 2008 - 2010, version 1.0

Pressing scientific questions concerning the Greenland ice sheet's climatic sensitivity, hydrology, and contributions to current and future sea level rise require hydrological datasets to resolve. While direct observations of ice sheet meltwater losses can be obtained in terrestrial rivers draining the ice sheet and from lake levels, few such datasets exist. We present a new dataset of meltwater river discharge for the vicinity of Kangerlussuaq, Southwest Greenland. The dataset contains measurements of river stage and discharge for three sites along the Akuliarusiarsuup Kuua (Watson) River's northern tributary, with 30 minute temporal resolution between June 2008 and August 2010. Additional data of water temperature, air pressure, and lake water depth and temperature are also provided. Discharge data were measured at sites with near-ideal properties for such data collection. Regardless, high water bedload and turbulent flow introduce considerable uncertainty. These were constrained and quantified using statistical techniques, thereby providing a high quality dataset from this important site. The greatest data uncertainties are associated with streambed elevation change and measurements. Large portions of stream channels deepened according to statistical tests, but poor precision of streambed depth measurements also added uncertainty. Quality checked data are freely available for scientific use as supplementary online material.

Composition of sedimentary rocks from the Shapkina River valley, Bolshezemelskaya Tundra

A facies-genetic and stratigraphic subdivision of the Quaternary sequence in the Shapkina River valley has been accomplished. The riverbank shows outcrops of three glacial complexes with different mineralogical-petrographic compositions and structural characteristics, which can be correlated and stratificated. Datings of intermoraine horizons (alluvial, marine, lacustrine, and lacustrine-boggy sediments) have been based on palynological and paleomicrotheriological data. The Middle Neopleistocene section can be divided into two till horizons corresponding to two autonomous glaciations (Pechora and Vychegda). They are separated by a member of subaqueous Rodionov sediments. The Pechora till formed in the course of glacier motions from the northeast. Glacial horizons are mainly composed of the Vychegda till transported from the Northwest terrigenous provenance. Lithology of the Upper Neopleistocene Polyarnyi till testifies to its formation in the upper course of the river from material transported from the Northeast terrigenous-mineralogical provenance in the upper course of the river and from the Fennoscandian glaciation center in the lower course of the river. The paper presents the first lithological investigation and substantiation of genesis of various facies of Neopleistocene intermoraine marine sediments (sediments of the beach and fore-beach zones and shallow-water shelf).

Carbon and oxygen isotope ratios, and geochemistry of the Precambrian-Cambrian Sukharikha River section, northwestern Siberian platform

A high-resolution carbon isotope profile through the uppermost Neoproterozoic-Lower Cambrian part of the Sukharikha section at the northwestern margin of the Siberian platform shows prominent secular oscillations of d13C with peak-to-peak range of 6-10 ?. There are six minima, 1n-6n, and seven maxima 1p-7p, in the Sukharikha Formation and a rising trend of d13C from the minimum 1n of -8.6 ? to maximum 6p of +6.4 ?. The trough 1n probably coincides with the isotopic minimum at the Precambrian-Cambrian boundary worldwide. Highly positive d13C values of peaks 5p and 6p are typical of the upper portion of the Precambrian-Cambrian transitional beds just beneath the Tommotian Stage in Siberia. A second rising trend of d13C is observed through the Krasnoporog and lower Shumny formations. It consists of four excursions with four major maxima that can be cor related with Tommotian-Botomian peaks II, IV, V, and VII of the reference profile from the southeastern Siberian platform. According to the chemostratigraphic cor relation, the first appearances of the index forms of archaeocyaths are earlier in the Sukharikha section than in the Lena-Aldan region.

Soil organic carbon storage and soil properties for 50 soil profiles in the Lena River Delta including land form description and map

To project the future development of the soil organic carbon (SOC) storage in permafrost environments, the spatial and vertical distribution of key soil properties and their landscape controls needs to be understood. This article reports findings from the Arctic Lena River Delta where we sampled 50 soil pedons. These were classified according to the U.S.D.A. Soil Taxonomy and fall mostly into the Gelisol soil order used for permafrost-affected soils. Soil profiles have been sampled for the active layer (mean depth 58±10 cm) and the upper permafrost to one meter depth. We analyze SOC stocks and key soil properties, i.e. C%, N%, C/N, bulk density, visible ice and water content. These are compared for different landscape groupings of pedons according to geomorphology, soil and land cover and for different vertical depth increments. High vertical resolution plots are used to understand soil development. These show that SOC storage can be highly variable with depth. We recommend the treatment of permafrost-affected soils according to subdivisions into: the surface organic layer, mineral subsoil in the active layer, organic enriched cryoturbated or buried horizons and the mineral subsoil in the permafrost. The major geomorphological units of a subregion of the Lena River Delta were mapped with a land form classification using a data-fusion approach of optical satellite imagery and digital elevation data to upscale SOC storage. Landscape mean SOC storage is estimated to 19.2±2.0 kg C/m**2. Our results show that the geomorphological setting explains more soil variability than soil taxonomy classes or vegetation cover. The soils from the oldest, Pleistocene aged, unit of the delta store the highest amount of SOC per m**2 followed by the Holocene river terrace. The Pleistocene terrace affected by thermal-degradation, the recent floodplain and bare alluvial sediments store considerably less SOC in descending order.

Geological investigation of a section at Kulyumbe river in Siberia

An integrated, high-resolution chemostratigraphic (C, O and Sr isotopes) and magnetostratigraphic study through the upper Middle Cambrian - lowermost Ordovician shallow-marine carbonates of the northwestern margin of the Siberian Platform is reported. The interval was analysed at the Kulyumbe section, which is exposed along the Kulyumbe River: an eastern tributary of the Enisej River. It comprises the upper Ust'-Brus, Labaz, Orakta, Kulyumbe, Ujgur, and lower Iltyk formations and includes the Steptoean positive carbon isotopic excursion (SPICE) studied here in detail from upper Cambrian carbonates of the Siberian Platform for the first time. The peak of the excursion, showing d13C positive values as high as +4.6? and least-altered 87Sr/86Sr ratios of 0.70909, is reported herein from the Yurakhian Horizon of the Kulyumbe Formation. The stratigraphic position of the SPICE excursion does not support traditional correlation of the boundary between the Orakta and Labaz formations at Kulyumbe River with its supposedly equivalent level in Australia, Laurentia, South China, and Kazakhstan, where the Glyptagnostus stolidotus and G. reticulatus biozones are known to immediately precede the SPICE excursion and span the Middle-Upper Cambrian boundary. The Cambrian-Ordovician boundary is probably situated in the middle Nyajan Horizon of the Iltyk Formation, in which carbon isotope values show a local maximum below a decrease in the upper part of the Nyajan Horizon, attributed herein to the Tremadocian. A refined magnetic polarity sequence shows that the geomagnetic reversal frequency was very high during the Middle Cambrian at 5-10 reversals per Ma, assuming a total duration of ~10 Ma and up to 100 magnetic intervals in the Middle Cambrian. By contrast, the sequence attributed herein to the Upper Cambrian on chemostratigraphic grounds contains only 10-11 magnetic intervals. Preprint in Open Access hdl:10013/epic.30209.d001