Latitude characteristics of the sunspot formation zone and the 11-year solar activity cycle

Using data of the extended Greenwich sunspot catalog for 1874–2006, annual average values of some quantities characterizing the latitude distribution of sunspot activity have been calculated. The quantity describing the width of the sunspot formation zone is closely correlated with the corresponding Wolf numbers. A latitude characteristic has been found that demonstrates in a particular time interval in the fourth year after the maximum of the current 11-year cycle a high correlation with the Wolf number at the maximum of the next cycle. This time interval is characterized by extreme differences between the speeds of the motion of the mean latitude and the upper boundary of the sunspot formation zone. A model displaying good stability and enabling forecasting of the amplitudes of the next 11-year cycles is constructed based on the found correlation. According to these forecasts, the activity of the next (24th) cycle will be 20–30% higher than in the previous one.     

Valence state of iron in a condensate from the Luna 16 regolith

This paper reports the results of an X-ray photoelectron spectroscopic study of the condensate phase of regolith sample L1639 returned by the Luna 16 mission. The reduced Si⁰, Si²⁺, Al⁰, Ti²⁺, and Ti³⁺ forms were detected in the sample. Iron occurs in all valence states, and Fe³⁺ species were detected for the first time in the condensate. Minor Fe³⁺ concentrations were observed in the upper layers of the sample containing the maximum amounts of condensate products. The fraction of ferric Fe is 22%, and the Fe⁰: Fe²⁺: Fe³⁺ proportion is 33: 45: 22. The appearance of ferric Fe in the lunar condensate is explained by the reaction of FeO disproportionation occurring either at the stage of the expansion and cooling of impact-related vapor or directly in the condensed phase on the surface of regolith particles. This interpretation is supported by the results of a model experiment on augite vaporization and condensation. The experiment simulating impact vaporization was carried out on a laser set-up at a temperature of ∼3000–4000 K and a pulse duration of ∼10⁻³ s in a He atmosphere (P = 1 atm). The results of analyses provided compelling evidence that the condensate produced after augite vaporization contains Fe in all oxidation states, and the proportions of different valence forms approach the stoichiometry of the disproportionation reaction.     

The Kaidun chondrite breccia: Petrology, oxygen isotopes, and trace element abundances

Oxygen isotope and trace element data for 13 samples of the Kaidun chondritic breccia reaffirm the complex polymict nature of this unique meteorite. Bulk Kaidun samples most closely resemble CR chondrites, but the matrix is CI-like. Two separated clasts are CR-like but have some properties that resemble CM, two clasts are enstatite chondrites (one EL and one EH), one clast is an aubrite-like metal-rich impact melt, and one clast is a unique layered olivine-bearing pyroxenite with the isotopic composition of an aubrite. Yet, although each clast resembles a known meteorite group, all deviate in some respect from the norms for those groups. Collectively, Kaidun has sampled materials not yet represented in the world meteorite collections and which greatly extend the definitions of known meteorite groups. Phyllosilicates in Kaidun span a very wide range in composition and vary from clast to clast, suggesting that the aqueous alteration experienced by the clasts predated assembly of the Kaidun parent body.     

Cyclostratigraphic Correlation of Cenomanian and Turonian Deposits of the Eastern European Platform

Depositional conditions at the Cenomanian–Turonian time have been specified and a cyclostratigraphic scheme of the correlation of the Turonian sections has been proposed based upon generalizations of our own results concerning sections of Voronezh anteclise, Ulyanovsk–Saratov trough, Crimea, and the Caucasus.     

Age of the Jombolok lava field (East Sayan): evidence from dendrochronology and radiocarbon dating

Dendrochronology and radiocarbon dating, with reference to remote sensing, digital elevation modeling, geological, and geomorphological data, provide new age constraints for the Jombolok lava field in the East Sayan Mountains (Siberia). The Jombolok lava field originated in the latest Late Pleistocene and underwent at least four phases of volcanic activity recorded in lava flows. Two earliest phases followed shortly one after another more than 13 kyr ago. The third phase corresponding to eruptions of Kropotkin volcano can be timed only relatively. The fourth phase has been dated by dendrochronology and AMS ¹⁴C of well-preserved wood buried under the youngest lava which occurs among older lavas near the Jombolok River mouth. The age of this activity is bracketed between the death of trees caused by eruptions 1268-928 years ago and the beginning of new tree growth on the surface of the most recent lavas 900 years ago.     

New hydrothermal sulfide fields of the Mid-Atlantic Ridge: Yubileinoe (20°09′ N) and Surprise (20°45.4′ N)

Two new sulfide fields (Yubileinoe, 20°09′ N, and Surprise, 20°45.4′ N) were discovered between 20°01′ and 20°54′ N within the Russian Application Area of the Mid-Atlantic Ridge (MAR). The Yubileinoe field is located at a depth of 2300–2550 m in the near-top area of the first rift ridge, which is a boundary of the western wall of the rift valley. This new field and the Zenith-Victory field, which was previously discovered in the eastern wall, occur symmetrically relative to the rift valley of this MAR segment. The Surprise field at a depth of 2800–2850 m is situated in the eastern wall of the rift valley, on the slope of the volcanic uplift. After the discovery of these inactive sulfide fields, the number of hydrothermal fields within the Russian Application Area reached ten.     

Main stages of tectonomagmatic activity of the Tuva–Mongolian microcontinent in the Precambrian: data on the U–Pb age of zircons

The U–Pb age of zircons from Ediacaran sandstones of the cover of the Tuva–Mongolian microcontinent and the rocks of its Early Precambrian basement (Gargan block) was analyzed by the LA–ICP–MS method. The major stages of tectonomagmatic activity of this block include the Neoarchean, Paleoproterozoic (no younger than 2 Ga), and Neoproterozoic. Comparison of the age of zircons from Ediacaran terrigenous rocks of the Tuva–Mongolian microcontinent and sandstones of the reference sections of the Ediacaran shelf of the Siberian platform undeniably indicates their independent accumulation.     

Bottom morphology and lithodynamic processes in the outfall offshore mouth zone and in the delta of the Northern Dvina River

The paper presents new data on the morpholithodynamic regime of the foredelta and deltaic branches of the Northern Dvina River. Based on data from field sonar investigations, the bottom structure and lithology of bottom sediments are described. Using hydrographic and topographic charts and satellite images, we traced the dynamics of deltaic branches and bottoms in the outfall offshore zone of the Northern Dvina River for the period of 1832–2013.     

On classification of sea surface oil films using TerraSAR-X satellite polarization data

The paper presents the results of applying a new polarization method proposed in [28] to identify the type of surface pollution and differentiate between mineral oil films (crude oil and its emulsion and petroleum products) and films of other origin in sea surface radar images. The method is based on calculation of the quantitative characteristics for the ratios of suppression or intensification of scattered radio signals of different physical nature, viz., caused by capillary ripples several centimeters long, or wave breaking. TerraSAR-X satellite coaxial-polarized (VV/HH) SAR images are used. The data for analysis have been collected in areas where spots and slicks of known origin regularly occur, such as oil spills and natural oil seeps in the Gulf of Mexico and the Caspian Sea, and biogenic films in the Caspian Sea. The results of analyzing radar images from the TerraSAR-X satellite with controlled experimental oil emulsion spills in the North Sea are used for comparison. Based on the analysis of ten TerraSAR-X radar polarization images with surface sensing angles greater than 30°, it is shown that this method makes it possible to distinguish between oil spills and slicks formed by natural oil seeps and biogenic films with an accuracy higher than 80% regardless of the observation area.