Sulfoarsenide complexes of gold in hydrothermal solutions in the formation of gold ore deposits (thermodynamic modeling)

The composition and conditions of the formation of gold sulfoarsenide complexes were studied by means of the solution of inverse problems of physicochemical modeling on the basis of the SELEKTOR software, with the computer analysis of the experimental data on Au dissolution in the presence of orpiment at 200–300°C and 1 kbar pressure. It was shown that sulfoarsenide complexes of gold formed in sulfurous-arsenious metalliferous hydrothermal solutions quantitatively prevailed in acidic and near-neutral solutions in the presence of As. The stability of the H₂AuAsS ₃ ⁰ sulfoarsenide complex and of its AuAsS ₂ ⁰ deprotonated analogue depends on the concentration of arsenic in the system, just as the ratio of sulfoarsenide and hydrosulfide complexes of gold. The productive metalliferous generations of sulfides in pyrite-arsenopyrite parageneses are deposited involving gold sulfoarsenides.     

Serum biochemical and cellular responses to experimental cupric ion challenge in mussels

Our intent has been to develop rapid and sensitive bioassay procedures for laboratory and field applications based on hemolymph factors in animals such as the bay mussel, Mytilus edulis. We found that mussel hemolymph could be easily and repeatedly sampled from individual animals in sufficient amounts to allow analyses for lysozyme, proteolytic activity, total protein and hemocyte counts. In static tests there seemed to be graded responses indicating release of increasing amounts of the above factors into the hemolymph in roughly direct proportion to Cu²⁺ concentration at lethal and sublethal levels. We interpreted this to be evidence for increased lysosomal and cellular disruption as cupric ion exposure was increased or prolonged. At the same time, Cu²⁺ concentrations in the mussel hemolymph increased up to an order of magnitude above ambient in the range of 26 to 267 ppb. We felt that this was evidence for the release of Cu-binding proteins into the mussel hemolymph. Simultaneously with the above events the serum granulocytes increased in numbers above control values by factors of 3 or 4 in response to copper challenge while macrophage (terminology of Moore & Lowe, 1977) counts, including controls, declined precipitously.     

The Middle and Upper Devonian in southeastern flank of the Siberian platform (Southern Verkhoyansk Region,Sette-Daban Mountain Range)

Data on Middle and Upper Devonian deposits studied in southeastern flank of the Siberian platform are considered. A scheme of stratigraphic zoning in the study region is presented. Nineteen sedimentological and biotic events, which are recorded in the studied sections, are of the regional, interregional and global ranks. Their connection with eustatic sea-level fluctuations is established. Sections of the formation and regional horizon stratotypes and parastratotypes are described. The revision of species Mucrospirifer novosibiricus (Toll) is carried out.     

Petrogenesis and geotectonic setting of the PanAfrican basement rocks in Bamenda Massif, Obudu Plateau, southeastern Nigeria： Evidence from trace element geochemistry

1 IntroductionThe study area is part of the Obudu Plateau,which forms part of the Precambrian Pan-African tec-tonothermal belt, lying between the West African Cra-ton and the Gabon-Congo Craton ( Fig. 1). It isbounded by the Benue Trough, in the NE-SW axi…     

Analysis of daily rainfall processes in lower extremadura (Spain) and homogenization of the data

Summary In this paper we analyze, from the point of view of stochastic processes, daily rainfall data recorded at the Badajoz Observatory (Southwestern Spain) since the beginning of the century. We attempt to identify any periodicities or trends in the daily rainfall occurrences and their dependence structure, and attempt to select the appropriate point stochastic model for the daily rainfall series.Standard regression analysis, graphical methods and the Cramer statistic show a rise in the number of cases of light rain (between 0.1 and 5 mm/d) and a decline in the number of cases of moderate to heavy rain (> 5 mm/d) in the daily rainfall at least at the 5% significance level.That the homogenization process was satisfactory is shown by the mean interarrival time of the homogenized series and the test of the rate of homogenized daily rainfall occurrences. Our analysis also shows that the behavior of the spectra of the homogenized daily rainfall counts is completely different from that of a Poisson process, so that the hypothesis of a non-homogeneous Poisson process is rejected.With 7 Figures     

The task of reconstructing the motion of an object by magnetic measurements

We examine the problem of determining the spatial position of a triaxial magnetometer onboard an artificial satellite by measuring the fields in orbit. Such a task is interesting from the point of view that to solve it, data on the satellite and the character of its motion in orbit are not used. We obtain explicit expressions for the Euler angles via the field components measured in orbit and taken from a field model, which is considered given.     

Lateral structural variability in zone of eocene island-arc-continent collision,Kamchatka

The lateral variability of structural elements in the collision zone of the Cretaceous-Paleocene Achaivayam-Valagin island arc with the northeastern Asian margin is considered. The similarity and difference of Eocene collision structural elements in the north and the south of Kamchatka are shown. In northern Kamchatka, the continent-arc boundary is traced along the Lesnaya-Vatyn Thrust Fault, which completed its evolution about 45 Ma ago. The thin, near-horizontal allochthon of this thrust, composed of island-arc rocks, overlies the deformed but unmetamorphosed terrigeneous sequences of the Asian margin. The general structure of this suture in the Kamchatka Isthmus and southern Koryakia is comparable with the uppermost subduction zone, where a thin lithospheric wedge overlaps intensely deformed sediments detached from the plunging plate. In southern Kamchatka (Malka Uplift of the Sredinny Range), the arc-continent collision started 55–53 Ma ago with thrusting of island-arc complexes over terrigenous rocks of continental margin. However, the thickness of the allochthon was much greater than in the north. Immediately after this event, both the autochthon and lower part of allochthon were deformed and subsided to a significant depth. This subsidence gave rise to metamorphism of both the autochthon (Kolpakov and Kamchatka groups, Kheivan Formation) and lower allochthon (Andrianovka and Khimka formations). The anomalously fast heating of the crust was most likely related to the ascent of asthenospheric masses due to slab breakoff, when the Eurasian Plate was plunging beneath the Achaivayam-Valagin arc.