New data on sedimentation and pedogenesis in the Selenga Midland (western Transbaikalia) during Late Glacial and Holocene

The investigation of soil-sedimentary sequences formed in different erosional and depositional environments in the central part of the Selenga Midland (western Transbaikalia region) during Late Glacial and Holocene made it possible to reveal nine periods of activation of exogenic processes and sedimentation and eight stages of intense pedogenesis, to define the specific features of these pedogenesis and sedimentation epochs, and to assess their duration. The data on the intensity of sedimentation and its influence on pedogenesis is demonstrated. Asynchronous development of exogenic processes and pedogenesis related to the landscapeâ “climate heterogeneity of the Selenga Midland have been revealed. The latter is reflected in more distinct epochs of intense exogenic processes in more arid southern areas of the midland and more durable periods of pedogenesis in humid climatic environments of its central part.     

The formation of graphite upon the interaction of subducted carbonates and sulfur with metal-bearing rocks of the lithospheric mantle

Experimental studies of the Fe⁰–(Mg, Ca)CO₃–S system were carried out during 18–20 h at 6.3 GPa, 900–1400°C. It is shown that the major processes resulting in the formation of free carbon include reduction of carbonates upon redox interaction with Fe⁰ (or Fe₃C), extraction of carbon from iron carbide upon interaction with a sulfur melt/fluid, and reduction of the carbonate melt by Fe–S and Fe?S–C melts. Reconstruction of the processes of graphite formation indicates that carbonates and iron carbide may be potential sources of carbon under the conditions of subduction, and participation of the sulfur melt/fluid may result in the formation of mantle sulfides.     

Silurian U–Pb zircon age (LA-ICP-MS) of granitoids from the Zelenodol Cu–porphyry deposit,Southern Urals

The Zelenodol porphyry Cu-(Au, Mo) deposit located about 65 km SSW of the city of Chelyabinsk is confined to the western part of the West Uralian Volcanogenic Megazone. The concordant U-Pb age of zircons from ore-bearing island-arc diorite porphyryis 418.3 Â ± 2.9 Ma.     

First results on determination of chlorophill <Emphasis Type="Italic">A</Emphasis> and its derivatives in the system of trapped sedimentary material–fluffy layer–bottom sediment of the Caspian Sea

The first data were obtained on the vertical chlorin flux in the water column and its accumulation in the upper layer of sediments of the Caspian Sea. Seasonal variability of the chlorine concentration in sedimentary matter was evaluated. The tendency of decrease in the phytoplankton-synthesized (allochtonous) organic matter content was revealed over approximately the past 60 years.     

Detachment folding in a Lower Cambrian–Upper Permian karst reservoir: 3D model of the Yubei 3D area (eastern Markit Slope,Tarim Basin,Northwest China)

A three-dimensional (3D) structural modeling of the Lower Cambrian–Upper Permian Yubei 3D area was performed to understand its structural evolution. This model reproduces the present-day structure of the basin and comprises 11 horizons within Lower Cambrian to Upper Permian rocks. The analysis is based on 3D depth views and faults. The results image salt movements due to tectonics and/or burial. From these observations, this paper deduces that salt structures are correlated to the main faults and tectonic events. From the model analysis, we interpret the timing and geometry of Tarim Basin tectonics. The fault geometry can be resolved based on the strike of the fault, the morphology of hanging wall strata, and the stratigraphic distribution. Emphasis is placed on gypsum rock detachment, considering its movements during the Middle Caledonian event and decoupling effects during tectonic evolution. Moreover, we point to the structural control of the Paleozoic basement and the crustal architecture (Yubei 3D Zone) on the geometry of the Tarim Basin.     

Cycles of seismic activity in the second half of the holocene in the Western Caucasus and their correlation with stages of civilization development: A case study of the upper reach of the Mzymta River

The results of comprehensive research into the area of the upper reach of the Mzymta River (Western Caucasus) are presented. The evidence of strong earthquakes that struck the study area throughout history is studied. The periods when mud flows and rockslides associated with the earthquakes are identified to fall between 3100–4000 and 700–1200 years ago. Paleoseismological results are correlated to the results of archeological excavations. As a result, it is revealed that the periods of tectonic disasters coincided with the onsets of the period when the area was uninhabited (abandoned) by people. The results of the present comprehensive research provide additional information to specify the seismic hazard and the chronology of human habitation in the region.     

Iceberg drifting and distribution in the Vilkitsky Strait studied by detailed satellite radar and optical images

This paper is devoted to the detection and identification of icebergs in the Russian Arctic Seas from the use of high- and medium-resolution radar and optical images from EROS-B, Radarsat-1, Radarsat-2, SPOT-4 and SPOT-5 Earth observation satellites. In July–September of 2011–2013, the SCANEX Research and Development Center, the Federal State Unitary Enterprise Atomflot, and other partner organizations provided operational satellite monitoring of icebergs in the Kara Sea and the Laptev Sea. More than 130 highly detailed optical and radar images were received and processed. The Vilkitsky Strait—one of the narrowest and most dangerous places within the Northern Sea Route—was chosen as an experimental polygon. As a result, iceberg location in the strait during the 2011–2013 navigation periods was analyzed, as were the iceberg size, area, drift direction, and height.     

Population genetic diversity and structure of a dominant tropical seagrass,Cymodocea rotundata,in the Western Pacific region

Cymodocea rotundata is an ecologically important tropical pioneer seagrass species distributed in the Indo‐Pacific region. The population genetic diversity and structure of this species were analysed at 46 sites spanning the Philippines, Ryukyu Islands (northern limit) and Hainan Island, by using microsatellite simple sequence repeat (SSR) markers. Analyses revealed the persistence of C. rotundata likely relies on local population dynamics and fitness influenced by environmental gradients, with sexual reproduction prevalent in the Philippines while the Ryukyu and Hainan populations were predominantly established by clonal spread. Analysis of molecular variance showed significant genetic differentiation (P < 0.001) among three geographic regions: the Philippines, Ryukyu and Hainan. Furthermore, the mean fixation index value was very high (F_ST = 0.36), indicating poor dispersal potential or limited gene flow. Allelic richness and heterozygosity of C. rotundata was comparable in the Philippines and Ryukyu Islands populations. More private alleles were found in the Philippines and excess heterozygotes in the Ryukyu Islands. STRUCTURE analysis revealed that the Ryukyu and Hainan populations were mosaics of admixed alleles of individuals from the Philippines. An assignment test suggested that recruitment occurs from the Northeast Philippines to Ryukyu Islands. These results suggest that the Philippine populations are tropical seagrass hotspots and perhaps the origin of the populations in the Ryukyu and Hainan Islands. This scenario is most likely driven by the Kuroshio Current and island integration events during plate tectonic activities. The Philippine Archipelago is considered of high importance for conservation objectives and management plan of seagrasses. Likewise, the Ryukyu Islands are also important in terms of conserving regional diversity because locally adapted genotypes have important evolutionary potential in the face of environmental change.     

西北太平洋海洋净初级生产力与柔鱼资源量变动关系的研究

海洋初级生产力在海洋生态中扮演重要角色,其变化影响了海洋渔业的潜在产量。本文根据2004-2013年中国鱿钓组提供的西北太平洋柔鱼(Ommastrephes bartramii)捕捞数据和海洋遥感净初级生产力数据,研究了柔鱼冬春生西部群体资源量变动与净初级生产力的关系。结果发现,柔鱼渔场范围内净初级生产力在经度方向上呈明显的季节性变化,冬春季低,夏秋季高。捕捞月份7-11月对应的适宜净初级生产力范围分别为500~700 mg/(m2·d)(以碳计),500~800 mg/(m2·d),500~1000 mg/(m2·d),500~800 mg/(m2·d)和300~500 mg/(m2·d),最适净初级生产力分别为700 mg/(m2·d),600 mg/(m2·d),700 mg/(m2·d),600 mg/(m2·d)和400 mg/(m2·d)。7-11各月最适净初级生产力平均纬度与捕捞努力量纬度重心呈显著正相关关系(P<0.05),说明了捕捞努力量位置在渔场中不是随机分布,可能受最适净初级生产力的纬度分布的影响。柔鱼年间资源丰度与各年3月份净初级生产力以及7-11月份平均净初级生产力大小显著正相关(P<0.05)。推测每年柔鱼资源量大小可能是由3月份产卵场海域和7-11月捕捞月份渔场净初级生产力水平交互作用的结果。研究表明,异常环境条件(厄尔尼诺和拉尼娜事件)对柔鱼产卵场和渔场的净初级生产力具有显著影响,但调控机制不同。