Solar System Collisions with Dense Interstellar Gas Clouds and Radiocarbon Traces of Periods with “Abnormally Low” Solar Modulation of Cosmic Rays

Geomagnetism and Aeronomy - The causes of a sharp increase in the radiocarbon content in the Earth’s atmosphere for periods with abnormally low solar modulation of galactic cosmic rays (GCRs)...     

Nature of Co-bearing ferromanganese crusts of the Magellan Seamounts (Pacific Ocean): Communication 2. Ion exchange properties of ore minerals

The results of experimental studies of ion exchange properties of Co-bearing ferromanganese crusts in the Magellan Seamounts (Pacific Ocean) are discussed. Maximum reactivity in reactions with the participation of manganese minerals (Fe-vernadite, vernadite) is typical of Na⁺, K⁺, and Ca²⁺ cations, whereas minimum activity is recorded for cations Pb²⁺ and Co²⁺. The exchange complex of ore minerals in crusts is composed of Na⁺, K⁺, Ca²⁺, Mg²⁺, and Mn²⁺ cations. The exchange capacity of manganese minerals increases from the alkali metal cations to rare and heavy metal cations. Peculiarities of the affiliation of Co²⁺, Mn²⁺, and Mg²⁺ cations in manganese minerals of crusts are discussed. In manganese minerals, Co occurs as Co²⁺ and Co³⁺ cations. Metal cations in manganese minerals occur in different chemical forms: sorbed (Na⁺, K⁺, Ca²⁺, Mn²⁺, Co²⁺, Cu²⁺, Zn²⁺, Cd²⁺, and Pb²⁺); sorbed and chemically bound (Mg²⁺, Ni²⁺, Y³⁺, La³⁺, and Mo⁶⁺); and only chemically bound (Co³⁺). It is shown that the age of crust, its preservation time in the air-dry state, and type of host substrate do not affect the ion exchange indicators of manganese minerals. It has been established that alkali metal cations are characterized by completely reversible equivalent sorption, whereas heavy metal cations are sorbed by a complex mechanism: equivalent ion exchange for all metal cations; superequivalent, partly reversible sorption for Ba²⁺, Pb²⁺, Co²⁺, and Cu²⁺ cations, relative to exchange cations of manganese minerals. The obtained results refine the role of ion exchange processes during the hydrogenic formation of Co-bearing ferromanganese crusts.     

Petrology and geochemistry of gabbro and picrites from the Altai collisional system of Hercynides: Evidence for the activity of the Tarim plume

We present petrological, isotopic, and geochronological data on gabbro-picrite plutons from the Altai collisional system of Hercynides (eastern Kazakhstan). The geological, geochemical, and geochronological data suggest that these rocks are indicators of the activity of the Tarim plume. The gabbro and picrites formed in two stages (~293 and 280 Ma) in an acid-to-basic succession, explained by a model for the interaction of thermochemical plumes with the lithosphere. Early igneous activity, which gave rise to subalkalic gabbro plutons, reflects the first interaction between the ascending plume and the lithosphere, with low-melting sublithospheric protoliths. Further interaction was characterized by the sublithospheric spread of the plume head with intense heating of the lithospheric base and possible intrusion of deep melts, which resulted in the formation of Cu–Ni–PGE gabbro-picrite plutons in the Altai collisional system and Northwest China.     

On the use of light scattering selectivity for the indication of the variability in the distributions of the large and small particles suspended in the water

The potentiality of the nephelometric indication of the relationship of small and large particles in shallow waters is investigated using a submersible nephelometer. One of its channels measures the light scattered from the water at an angle of 90° in the blue spectrum, while the other does the same in the far red. The results of the field observations demonstrate differences in the vertical distributions of the signals of the channels supposedly due to the vertical variations in the ratio of the concentration of the small and large particles.     

Long-term oscillations of sunspots and a special class of artifacts in SOHO/MDI and SDO/HMI data

A specific type of artifacts (named as “p2p”), that originate due to displacement of the image of a moving object along the digital (pixel) matrix of receiver are analyzed in detail. The criteria of appearance and the influence of these artifacts on the study of long-term oscillations of sunspots are deduced. The obtained criteria suggest us methods for reduction or even elimination of these artifacts. It is shown that the use of integral parameters can be very effective against the “p2p” artifact distortions. The simultaneous observations of sunspot magnetic field and ultraviolet intensity of the umbra have given the same periods for the long-term oscillations. In this way the real physical nature of the oscillatory process, which is independent of the artifacts have been confirmed again. A number of examples considered here confirm the dependence between the periods of main mode of the sunspot magnetic field long-term oscillations and its strength. The dependence was derived earlier from both the observations and the theoretical model of the shallow sunspot. The anti-phase behavior of time variations of sunspot umbra area and magnetic field of the sunspot demonstrates that the umbra of sunspot moves in long-term oscillations as a whole: all its points oscillate with the same phase.     

Recognition of possible locations of future M ≥ 6.0 earthquakes: The Mediterranean mountain belts

The goal of the present work is to identify high-seismicity (High) intersections of morphostructural lineaments within the Mediterranean mountain belts (the Alps, Apennines, Balkanides, Dinarides, and the Carpathians). The intersections of lineaments, with the lineaments being boundaries of crustal blocks, were determined by morphostructural zoning. The epicenters of M ≥ 6.0 earthquakes and the intersections were found to be related. We used the KORA-3 recognition algorithm to identify the High intersections, where M >- 6.0 earthquakes can occur, separately for each mountainous country. Most of the High intersections identified here are located on higher-rank lineaments that separate major crustal blocks. The High intersections typically involve contrasting neotectonic movements and an increased crustal fragmentation. The results of this study point to a high seismic potential for the regions studied: we have identified many High intersections where no large earthquakes have yet been recorded.     

Neue Vorstellungen über den Tiefbau von Vorsenken

Zusammenfassung Der geologische Tiefenbau und die Entwicklungsgeschichte der Kopetdag-, Terek-Kaspi-, Indol-Kuban- und Karpaten-Vorsenke sind ähnlich. Es zeigt sich, daß die genannten Vorsenken keine Zonen kurzzeitiger Durchbiegungen sind, die sich in der orogenen Schlußentwicklungsetappe des alpidischen Faltengebietes gebildet haben, sondern daß sie langlebige negative Strukturen darstellen. Die Intensität ihrer Durchbiegung zu Beginn des alpidischen geotektonischen Zyklus (in der Jura und Kreidezeit) ist mit der Größe der Absenkung im Neogen-Quartär vergleichbar. Im Verlaufe des gesamten alpidischen Zyklus entwickelten sich die Senken posthum.Überall dort, wo notwendige geophysikalische Untersuchungen durchgeführt wurden, wurde unter diesen Senken unterhalb eines mächtigen alpidischen Gesteinskomplexes ein genauso mächtiger Sedimentkomplex variszischen Alters festgestellt. Territorial fallen die Zonen der maximalen Mächtigkeiten des variszischen und alpidischen Gesteinskomplexes zusammen.

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Structure and development of the Pre-Copetdag, Terek-Caspian, Indol-Kuban, and Pre-Carpathian fore deeps are similar. The fore deeps were not zones of short term subsidence during the final stage of orogenic development of the Alpine folded belt, but they were long term subsidence zones. The rates of subsidence at the beginning of the Alpine geotectonic cycle (during Jurassic and Cretaceous) and at the end of the cycle (during Neogene and Quaternary) are comparable.Wherever geophysical investigations were carried out in this zone, beneath the Alpine sediments a Hercynian sediment complex of equal thickness was found. The areas of maximum thickness in both complexes coincide.

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Résumé La structure géologique et le développement historique des avant-fosses de Copetdag, Terek-Caspienne, Indol-Kouban et des Carpates sont semblables. Il appert que ces dépressions ne sont pas des zones d'inflexion de courte durée qui se sont formées pendant l'étape finale du plissement alpin, mais qu'ils présentent des structures négatives de longue durée. L'intensité de leur affaissement au commencement du cycle géotectonique alpin (au Jurassique et au Crétacé) est comparable, en grandeur, avec celui de la période néogène-quaternaire. Au cours de l'ensemble du cycle alpin, les dépressions se sont développées de façon posthume.Partout où ont eu lieu des explorations géophysiques, nous avons découvert sous ces avant-fosses, un épais complexe de roches alpines, et sous elles un complexe aussi puissant de sédiments varisques. Spatialement les zones des puissances maximum des complexes alpins et varisques coïncident.

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