Structural specificity of pleistocene loess and soil formation of the southern Russian plain according to materials of Eastern Priazovie

Doklady Earth Sciences -     

Speleogenesis of Selected Caves beneath the Lunan Shilin and Caves of Fenglin Karst in Qiubei, Yunnan

Yunnan is famous for its attractive karst landscapes especially shilins, fengcong and fenglin. The development of caves beneath the shilins in the vicinity of Lunan is closely connected with the formation of shilins. Most of the waters percolating through shilins run through the caves beneath them and are responsible for their formation. The study of cave speleogenesis deepens knowledge about both the development of shilins and karst structure. In the vicinity of the Lunan Shilin, speleological, morphological and structural geological studies of four karst caves have been accomplished. At Puzhehei, Qiubei, which is characterised by numerous fenglin, fengcong and caves, speleological and morphological studies have been performed. Cave sediments for paleomagnetic analyses have been taken from all studied areas (samples CH 1-9). Karst caves in SE Yunnan are probably much older than the age of the cave sediments (<780,000 years B.P.). The studied areas are located in the vicinity of the Xiaojiang fault (N-S     

A New Tool for Inundation Modeling: Community Modeling Interface for Tsunamis (ComMIT)

Almost 5 years after the 26 December 2004 Indian Ocean tragedy, the 10 August 2009 Andaman tsunami demonstrated that accurate forecasting is possible using the tsunami community modeling tool Community Model Interface for Tsunamis (ComMIT). ComMIT is designed for ease of use, and allows dissemination of results to the community while addressing concerns associated with proprietary issues of bathymetry and topography. It uses initial conditions from a precomputed propagation database, has an easy-to-interpret graphical interface, and requires only portable hardware. ComMIT was initially developed for Indian Ocean countries with support from the United Nations Educational, Scientific, and Cultural Organization (UNESCO), the United States Agency for International Development (USAID), and the National Oceanic and Atmospheric Administration (NOAA). To date, more than 60 scientists from 17 countries in the Indian Ocean have been trained and are using it in operational inundation mapping.     

The July 15, 2009 Fiordland,New Zealand Tsunami: Real-Time Assessment

On 15 July 2009, a Mw 7.8 earthquake occurred off the New Zealand coast, which by serendipitous coincidence occurred while the International Tsunami Symposium was in session in Novosibirsk, Russia. The earthquake generated a tsunami that propagated across the Tasman Sea and was detected in New Zealand, Australia and as far away as the US West coast. Small boats close to the epicenter were placed in jeopardy, but no significant damage was observed despite a measured run-up height of 2.3 m in one of the Sounds in close proximity to the source (Wilson in GNS Science Report 46:62 2009). Peak-to-trough tsunami heights of 55 cm were measured at Southport, Tasmania and a height of 1 m was measured in Jackson Bay, New Zealand. The International Tsunami Symposium provided an ideal venue for illustration of the value of immediate real-time assessment and provided an opportunity to further validate the real time forecasting capabilities with the scientific community in attendance. A number of agencies with responsibility for tsunami forecast and/or warning, such as the NOAA Center for Tsunami Research, the Pacific Tsunami Warning Center, GNS Science in New Zealand, the Australian Bureau of Meteorology and the European Commission Joint Research Centre were all represented at the meeting and were able to demonstrate the use of state of the art numerical models to assess the tsunami potential and provide warning as appropriate.     

Estimation of the acceleration of the solar-system barycenter relative to a system of reference quasars

It is shown that geodetic VLBI observations can be used to estimate the external acceleration of the barycenter of the solar system. This relies on the fact that, in special relativity, the acceleration of the motion of a coordinate origin relative to reference points leads to a drift in the secular aberration, manifest as systematic proper motions of the reference points in the direction of the acceleration vector. The VLBI time-delay equation is modified such that the acceleration vector appears in explicit form. Formulas for a new form of the fundamental VLBI equation and its partial derivative with respect to the acceleration are presented.     

Evolution of Ore-Forming Metasomatic Processes at Large Skarn Iron Deposits Related to the Traps of the Siberian Platform

The paper presents systematized and synthesized data on the parameters and evolutionary sequence of metasomatic processes that accompanied interaction between Permian–Triassic trap complex and rocks of the sedimentary cover of the Siberian Platform at the large skarn iron deposits. Relations of the textural–compositional, morphological, and genetic diversity of the skarns and ores with the phases and stages of the origin of ore-bearing volcano-tectonic edifices are demonstrated with reference to the Korshunovskoe and Rudnogorskoe deposits. The genetic reconstructions are based on survey materials and data on the mineralogy of the rocks and ores (obtained by optical and scanning electron microscopy, microprobe analysis, EPR, Raman and IR spectroscopy, and by studying inclusions in minerals). A principally important feature of the volcano-tectonic edifices of the large mineral deposits is their multistage evolution and combinations of fluid-conducting zones, which are related to (1) volcanic apparatuses, (2) shallow-depth magmatic chambers (laccoliths) hosted in carbonate–salt rocks, and (3) multistage fracture structures produced by the collapse of the leached space. The major ore-bearing structures were formed simultaneously with the development of an intermediate magmatic chamber hosted in Cambrian carbonate–salt rocks beneath a seal of terrigenous sedimentary rocks. Magmatic-stage magnesian skarns with disseminated ores in them and in the calciphyres were produced during the prograde stage in the apical parts of the laccoliths, at contacts between the dolerites and dolomites. During the early prograde stage, skarn–ore bodies developed around injection bodies of globulated dolerites, laccoliths, and sills; stockworks and steep bodies of fragmentary magnesian and calcic skarns and ores were formed within the diatremes; and conformable bodies and veins were produced in the splay fracture zones. The later reactivation of faults and fractures and the involvement of connate brines and solutions from the evaporite complex triggered the redeposition of the ore masses, crystallization of the mineral assemblages of hydrated skarns, development of large domains of serpentine–chlorite–epidote–amphibole rocks, calcic skarns, and ores. Data on multiphase fluid inclusions in the forsterite, apatite, and halite indicate that the mineral-forming fluid initially was a highly concentrated solution–melt (total salinity of 60%) with high-density reduced gases. The magnesian skarns were formed during the following stages: (1) forsterite + fassaite + spinel + first-population magnetite (820–740°C); (2) phlogopite + titanite + pargasite + second-population magnetite (600–500°C), and (3) clinochlore + serpentine + tremolite + pyrrhotite + chalcopyrite (≥450°C).     

Three‐body problem periodic orbits with vanishing angular momentum

Periodic solutions of the general three‐body problem are investigated in the shape space. Two different solutions are considered: the first is an extension of the well‐known figure‐eight orbit, and the second one is from the free‐fall problem. Using the shape space, we reduce the dimension of the problem. These orbits are obtained numerically and described on the Euclidean plane and on the shape sphere. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Linear collapse of spatially linear,three-dimensional,potential null points

The collapse of the magnetic field in the vicinity of a null point creates a large electrical current. Non-ideal effects in the surrounding plasma can then allow the onset of magnetic reconnection, which is important in many astrophysical phenomena. An elegant technique is used to show that spatially linear, initially potential, three-dimensional null points have a tendency to collapse with a growth of either the spine current or the fan current or a combination of both. The rate of collapse is determined for an incompressible plasma flow with open boundary conditions. An initial plasma flow affects the rate of collapse by speeding it up.     

Stars of early types in the region of the Orion Stellar association OB1 from observations of the glazar space telescope

Byurakan Astrophysical Observatory; SKB Granit; Geneva Observatory; Cosmonaut Preparation Center. Translated from Astrofizika, Vol. 32, No. 2, pp. 197–202, March–April, 1990.