Techniques for minimizing radiometric striping effects in Landsat data

Histogram normalization and statistical methods which are implemented at National Remote Sensing Agency, for minimizing radiometric distortions due to striping in the Landsat data are presented in this paper. Also the paper discusses the method of implementation of the above two methods on Multispectral Data Analysis System (M-DAS).     

Radiophysical Monitoring of the Lake Baikal Ice Cover

Presented are the results of the winter 2014 radiophysical expedition, within the framework of which the Baikal ice cover was investigated by electromagnetic methods. The primary objectives the expedition were to detect irregularities in the ice cover, such as cracks and thawing steamed holes in the ice, and to determine the ice thickness and structure in the area of the thawing holes by the GPR sounding method. We used in the experiments the OKO-2 ground-penetrating radar (GPR) of the decimeter band and the nanosecond radar with the wavelength of 3 cm. The measurements were made carried out from the Khivus hovercraft and from the UAZ automobile. The ice thickness of Lake Baikal was determined by non-contact electromagnetic measurement methods. Radargrams of reflected signals from the ice cover are presented. Radar patterns of reflected signals from artificial irregularities of the ice cover were obtained by the short-pulse radar method. The concept of radiophysical monitoring is suggested, which provides a means of determining the ice cover parameters of a water body with high spatial resolution. We present an integral approach to investigating the conditions of the ice cover in order to integrate different physicochemical methods for diagnosing the objects studied. A further development of the concept of integrated ice cover research, and the creation of the monitoring network involves solving a number of scientific and engineering tasks that include developing physical models and information and measurement systems as well as the rationale for an integrated monitoring network.     

Morphology and Structural Features of the Subduction Zone in the Vicinity of Kuril–Kamchatka–Aleutian Junction

Oceanology - The specific morphology of the inner and outer slopes of the eastern Kuril–Kamchatka Trench were revealed based on joint study of bathymetry and seismic profiles obtained in two...     

Iron speciation in minerals and glasses probed by $$\hbox{M}_{2/3}$$-edge X-ray Raman scattering spectroscopy

We present a spectroscopic study of the iron \(\hbox{M}_{2/3}\)-edge for several minerals and compounds to reveal information about the oxidation state and the local coordination of iron. We describe a novel approach to probe the iron \(\hbox{M}_{2/3}\)-edge bulk sensitively using X-ray Raman scattering. Significant changes in the onset and shape of the Fe \(\hbox{M}_{2/3}\)-edge were observed on ferrous and ferric model compounds with Fe in octahedral and tetrahedral coordination. Simulation of the spectra is possible using an atomic multiplet code, which potentially allows determination of, e.g., crystal-field parameters in a quantitative manner. A protocol is discussed for determination of the Fe oxidation state in compounds by linear combination of spectra of ferric and ferrous end members. The presented results demonstrate the capabilities of Fe \(\hbox{M}_{2/3}\)-edge spectroscopy by X-ray Raman scattering to extract information on the ratio of trivalent to total iron \(\hbox{Fe}^{3+}/\sum \hbox{Fe}\) and local coordination. As X-ray Raman scattering is performed with hard X-rays, this approach is suitable for in situ experiments at high pressure and temperature. It thus may provide indispensable information on oxidation state, electronic structure and local structure of materials that are important for physical and chemical processes of the deep Earth.     

Early Cambrian granitoids of North Gondwana margin in the transition from a convergent setting to intra-continental rifting (Ossa-Morena Zone,SW Iberia)

Two distinct Cambrian magmatic pulses are recognized in the Ossa-Morena Zone (SW Iberia): an early rift-(ER) and a main rift-related event. This Cambrian magmatism is related to intra-continental rifting of North Gondwana that is thought to have culminated in the opening of the Rheic Ocean in Lower Ordovician times. New data of whole-rock geochemistry (19 samples), Sm–Nd–Sr isotopes (4 samples) and ID–TIMS U–Pb zircon geochronology (1 sample) of the Early Cambrian ER plutonic rocks of the Ossa-Morena Zone are presented in this contribution. The ER granitoids (Barreiros, Barquete, Calera, Salvatierra de los Barros and Tablada granitoid Massifs) are mostly peraluminous granites. The Sm–Nd isotopic data show moderate negative εNdt values ranging from ?3.5 to +0.1 and TDM ages greatly in excess of emplacement ages. Most ER granitoids are crustal melts. However, a subset of samples shows a transitional anorogenic alkaline tendency, together with more primitive isotopic signatures, documenting the participation of lower crust or mantle-derived sources and suggesting a local transient advanced stage of rifting. The Barreiros granitoid is intrusive into the Ediacaran basement of the Ossa-Morena Zone (Série Negra succession) and has yielded a crystallization age of 524.7 ± 0.8 Ma consistent with other ages of ER magmatic pulse. This age: (1) constrains the age of the metamorphism developed in the Ediacaran back-arc basins before the intrusion of granites and (2) defines the time of the transition from the Ediacaran convergent setting to the Lower Cambrian intra-continental rifting in North Gondwana.     

Isotopic composition of pyritic sulfur from the mud volcanic ejecta in Azerbaijan

Geochemical studies of pyrite crystals from the mud volcanic ejecta in Azerbaijan were studied. It is shown that all of them have cubic shape. Determination of the sulfur isotope composition revealed a wide variation range of δ³⁴S values from–27.0 to +26.4‰. Signs of spatial zonation were recorded in the distribution of δ³⁴S values—lower values are confined to the present-day coastline of the Caspian Sea. Appearance of pyrite with a high share of ³⁴S is attributed to sulfate reduction that takes place in an environment with excess organic matter. It is supposed that the isotopically heavy sulfides represent the “neck” facies that are formed at the periphery of mud volcanic conduits at the contact of the hydrocarbon-rich mud volcanic fluids with stratal waters of host sediments.     

Neoproterozoic complexes of the shelf cover of the Dzabkhan terrane basement in the Central Asian Orogenic Belt

The formation stages of high-grade metamorphic complexes and the related granitoids of the Dzabkhan terrane basement are considered. The age data (U–Pb method, TIMS) of zircons from the trondhjemite block of the eastern part of the Dzabkhan terrane, which is directly overlain by the dolomite sequence of the Tsagaan Oloom Formation, are given. Trondhjemites yield the U–Pb zircon age of 862 ± 3 Ma. In their structural position, they are assigned to typical postmetamorphic formations that determine the formation and cratonization of rocks of the host block. The geochronological study of trondhjemites gives grounds to distinguish fragments of the continental crust in the Dzabkhan terrane basement, the formation of which occurred at different periods of time: ～860 and ～790 Ma. Geological–geochronological and Sm?Nd isotope–geochemical studies indicate that the Dzabkhan terrane basement is not a single block of the Early Precambrian continental crust, but a composite terrane, comprising Neoproterozoic ensialic and island-arc structural and compositional complexes. Correlation of Sr isotopic characteristics with the ⁸⁷Sr/⁸⁶Sr variation curve in the Neoproterozoic and Cambrian seawater shows that carbonate deposits accumulated at the eastern margin of the Dzabkhan terrane near the end of the Neoproterozoic, 700–550 Ma, and in the central part of the terrane in the Early Cambrian, 540–530 Ma.     

The sulfur species in hot rocky exoplanet atmospheres

The first JWST observations of hot Jupiters showed an unexpected detection of SO ${}_2$ in their hydrogen-rich atmospheres. We investigate how much sulfur can be expected in the atmospheres of rocky exoplanets and which sulfur molecules can be expected to be most abundant and detectable by transmission spectroscopy. We run thermochemical equilibrium models at the crust–atmosphere interface, considering surface temperatures 500–5000 K, surface pressures 1–100 bar, and various sets of element abundances based on common rock compositions. Between 1000 and 2000 K, we find gaseous sulfur concentrations of up to 25% above the rock in our models. SO ${}_2$, SO, H ${}_2$S, and S ${}_2$ are by far the most abundant sulfur molecules. SO ${}_2$ shows potentially detectable features in transmission spectra at about 4 $\mu$m, between 7 and 8 $\mu$m, and beyond 15 $\mu$m. In contrast, the sometimes abundant H ${}_2$S molecule is difficult to detect in these spectra, which are mostly dominated by H ${}_2$O and CO ${}_2$. Although the molecule PS only occurs with concentrations ppm, it can cause a strong absorption feature between 0.3 and 0.65 $\mu$m in some of our models for high surface pressures. The detection of sulfur molecules would enable a better characterization of the planetary surface.