Energy Spectra of Cosmic-Ray Protons and Nuclei Measured in the NUCLEON Experiment Using a New Method

Astronomy Reports - Some results of studies of cosmic rays obtained during the NUCLEON space experiment in 2015–2017 are presented. This experiment was intended for direct measurements of the...     

Adularia,the characteristic mineral of felsic spilites

Sea floor rhyolites from the Iberian Pyrite Belt show strong enrichment in potassium and adularia is observed to replace plagioclase. This process is in accord with thermodynamic data for the exchange reaction with ocean water which favours adularia up to about 140° C. Archaean felsic intrusives and extrusives exhibit sodium enrichment, a contrast which we attribute to lower K levels in sea water and, or, higher ocean temperatures. All of these rocks show ¹⁸O enrichment of + 6 to + 8, in compliance with low temperature sea water exchange.     

Mesozoic tectonic evolution of the Southeast China Block: New insights from basin analysis

In order to better understand the Mesozoic tectonic evolution of Southeast China Block (SECB in short), this paper describes geological features of Mesozoic basins that are widely distributed in the SECB. The analyzed data are derived from a regional geological investigation on various Mesozoic basins and a recently compiled 1:1,500,000 geological map of Mesozoic–Cenozoic basins. Two types of basin are distinguished according to their tectonic settings, namely, the post-orogenic basin (Type I) and the intracontinental extensional basin (Type II); the latter includes the graben and the half-graben or faulted-depression basins. Our studies suggest that the formation of these basins connects with the evolution of geotectonics of the SECB. The post-orogenic basin (Type I) was formed in areas from the piedmont to the intraland during the interval from Late Triassic to Early Jurassic; and the formation of the intracontinental extensional basin (Type II) connects with an intracontinental crustal thinning setting in the Late Mesozoic. The graben basin was generated during the Middle Jurassic and is associated with a bimodal volcanic eruption; and the half-graben or faulted-depression basin, filled mainly by the rhyolite, tuff and sedimentary rocks during Early Cretaceous, is occupied by the Late Cretaceous–Paleogene red-colored terrestrial clastic rocks. We noticed that the modern outcrops of numerous granites and basins occur in a similar level, and the Mesozoic granitic bodies contact with the adjacent basins by large normal faults, suggesting that the modern landforms between granites and basins were yielded by the late crustal movement. The modern basin and range framework was settled down in the Cretaceous. Abundant sedimentary structures are found in the various basins, from that the deposited environments and paleo-currents are concluded; during the Late Triassic–Early Jurassic time, the source areas were situated to the north and northeast sides of the outcrop region. In this paper, we present the study results on one geological and geographical separating unit and two separating fault zones. The Wuyi orogenic belt is a Late Mesozoic paleo-geographically separating unit, the Ganjiang fault zone behaves as the western boundary of Early Cretaceous volcanic rocks, and the Zhenghe–Dapu fault zone separates the SE-China Coastal Late Mesozoic volcanic-sedimentary basins and the Wuyi orogenic belt. Finally, we discuss the geodynamic mechanisms forming various basins, proposing a three-stage model of the Mesozoic sedimentary evolution.     

Upper Cretaceous carbonate hosted zinc–lead–barite deposits in Northern Thrust Zone, northern Iraq: petrography and geochemistry

Zinc–lead–barite deposits located in Lefan and Lower Banik localities of about 25 km northeast of Zakho City, Northern Iraq consist of a group of strata-bound sulfides hosted in Upper Cretaceous (Upper Campanian–Maastrichtian) dolomitic limestone. Carbonate-hosted ores contain 3.77% Zn, 2% Pb, and 5% Fe, while in lower Banik, they contain 1.5% Zn, 0.37% Pb, and 1.4% Fe. Diagenetic processes, such as dolomitization and recrystalization in addition to the type of microfacies, provided appropriate physical and chemical conditions that permitted the passage of ore-bearing fluids and participated in precipitation and ore localization. These deposits are precipitated in a platform and developed within the Foreland Thrust Belt. Ore precipitated as infill of intergranular dolomite porosity with replaced dolomite and rudist shells forming disseminated crystals that occupy intergranular pore spaces around dolomite and calcite and as infill of dissolution spaces and fractures.     

Surfactants enhanced recovery of endosulfan from contaminated soils

Soil pollution due to hydrophobic organic compounds is a wide environmental problem. Extensive use of endosulfan in cotton and paddy to meet the needs of the growing population has led to contamination of soil and other ecosystems. Endosulfan is hydrophobic, highly toxic to aquatic and human population and persists in soil for more than a year. To overcome the problem of hydrophobicity and limited availability, surfactants play a major role in soil remediation. In the present study, the potential of non-ionic synthetic surfactants (Tween 80, Triton X-100) and biosurfactant (Surfactin produced by Bacillus subtilis) for enhancing the release of endosulfan from contaminated agricultural soils was evaluated using the batch method. Incorporation of the surfactant concentrations at above Criticle Miceller Concentration (0.5, 1 and 2 g/L) into soil enhances the release of endosulfan. Surfactin produced from Bacillus subtilis recorded maximum (91.5%) recovery. The observed order of recovery being surfactin > Tween 80 > Triton X-100. The result suggest that surfactants could help in the remediation of soils polluted by pesticides.     

The stiff upper LIP: investigating the High Arctic Large Igneous Province

The Canadian Arctic Islands expose a complex network of dykes and sills that belong to the High Arctic Large Igneous Province (HALIP), which intruded volatile‐rich sedimentary rocks of the Sverdrup Basin (shale, limestone, sandstone and evaporite) some 130 to 120 million years ago. There is thus great potential in studying the HALIP to learn how volatile‐rich sedimentary rocks respond to magmatic heating events during LIP emplacement. The HALIP remains, however, one of the least well known LIPs on the planet due to its remote location, short field season, and harsh climate. A Canadian–Swedish team of geologists set out in summer 2015 to further explore HALIP sills and their sedimentary host rocks, including the sampling of igneous and meta‐sedimentary rocks for subsequent geochemical analysis, and high pressure‐temperature petrological experiments to help define the actual processes and time‐scales of magma–sediment interaction. The research results will advance our understanding of how climate‐active volatiles such as CO_2, SO₂ and CH₄ are mobilised during the magma–sediment interaction related to LIP events, a process which is hypothesised to have drastically affected Earth's carbon and sulphur cycles. In addition, assimilation of sulphate evaporites, for example, is anticipated to trigger sulphide immiscibility in the magma bodies and in so doing could promote the formation of Ni‐PGE ore bodies. Here we document the joys and challenges of ‘frontier arctic fieldwork’ and discuss some of our initial observations from the High Arctic Large Igneous Province.     

Staurolite-quartzite bands in kyanite quartzite at Big Rock,Rio Arriba County,New Mexico — A discussion

Schreyer and Chinner (1966) described staurolite-quartzite bands of unusual bulk chemical composition associated with the Big Rock kyanite deposit in northern New Mexico. They discussed two possible hypotheses-syngenetic or metasomatic-for the origin of the bands. This paper discusses additional evidence in support of the metasomatic hypothesis.Quartz-muscovite schist and quartz-kyanite rock are believed to be metarhyolite that was altered metasomatically by hydrothermal activity during metamorphism. Experimentally demonstrable reactions that involve ionic exchange equilibria between pore fluid and solid phases best explain the observed alteration. Staurolite-quartzite bands are postulated to be basalts or amphibolites that were hydrothermally altered in a manner analogous to alteration of the enclosing rocks. The process would deplete a basaltic parent rock in alkali and alkaline earth elements and produce a chemical composition similar to the bulk chemical composition of staurolite-quartzite.Schreyer and Chinner used textural evidence to prove that staurolite formed at the expense of chloritoid. Based on the chemical compositions of staurolite and relict chloritoid reported by them, several chemical equations were constructed, using the principle of ionic equilibria between pore fluid and solid phases, in an attempt to realistically portray the reaction. It is suggested that, under open-system metasomatic conditions, the ratio a_Mg+2/a_H+ in the supercritical aqueous fluid is an important parameter that controls the stability of chloritoid vs. staurolite.