Relics of near-bottom fauna in massive sulfide ores

The additional study of ancient volcanogenic massive sulfide deposits in various regions revealed microtextures, probably of biogenic origin, which could represent varieties of the shells of mineralized fauna. The new finds expand the list of sites containing relics of bioforms associated with hydrothermal vents of "black smokers".

Worldview Aspect of the Evolutionary-Projective Philosophy of Russian Cosmism

The article examines two worldview strategies of the evolutionary-projective philosophy of Russian Cosmism: the strategy associated with elimination of human corporeality, which has found adherents in current transhumanism, and the strategy proposed by humanistic worldview paradigm that directs humanity to the implementation of a deontological noospheric project of coevolution of planetary nature and society as a necessary condition for progress of our socio-natural universe. The focus is on analysis of the worldview insights of Russian Cosmists. In particular, the article addresses Vladimir Vernadsky’s worldview concepts regarding the changing role of man in nature and society. This is caused by changes in material resources, methods and degree of man’s transformation of the world as a result of the use of the microworld’s objects and processes as tools of labor (which are now called nanotechnologies). Among V.I. Vernadsky’s major insights that have been successfully verified in social practice, the article considers such worldview conceptions as orientation toward peaceful use of nuclear energy and the inevitability of replacing organic energy sources with inorganic ones; the need to maintain invariability of the biogenic constants of the planetary ecosystem (biosphere); human autotrophy – providing mankind with abiogenic food and other technogenic resources instead of substances and resources of biogenic origin; formation of a specific hu man person as a factor in the evolution of a planetary socio-natural whole. Taken together, all of these are due to the change in the place and role of modern man in nature and society, and these are also reflected in the formation of an ideological paradigm that is adequate to new trends in the practical evolution of the planetary socio-natural whole.

Extreme fractionation of selenium isotopes and possible deep biospheric origin of platinum nuggets from Minas Gerais, Brazil

Platinum-rich nuggets offer an opportunity for understanding how precious metals accumulate. We analyzed the selenium (Se) isotopic composition of Se-rich (102–103 μg g–1) platinum-palladium (Pt-Pd) nuggets from a recent placer deposit in Minas Gerais, Brazil, for which a biogenic origin has been inferred. We obtained Se isotopic values with a relatively narrow range (δ82/76SeNIST3149 = –17.4‰ to –15.4‰ ± 0.2‰, two standard deviations [2 SD]). The Pt-Os age of the nuggets is 181 ± 6 Ma (2 SD). The data indicate that the nuggets did not form in the recent placer deposit, but by replacement of hydrothermal vein minerals at ~70 °C and at least 800 m below the surface. The high abundance and extreme isotopic composition of Se as well as the presence of other biophilic elements like iodine, organic carbon, and nitrogen within the nugget matrix are consistent with a microbial origin. Although abiogenic reduction of Se oxyanions cannot be ruled out, the nuggets plausibly record Se-supported microbial activity in the deep biosphere.

FORMATION CONDITIONS OF GROUNDWATER OF THE UPPER JURASSIC OF THE CENTRAL REGIONS OF THE ZAURAL MEGAMONOCLYSIS

The article presents the first results of complex isotope-hydrogeochemical studies of reservoir waters of the Upper Jurassic deposits of the central regions of the Zaural megamonoclysis. It was shown that most waters have a narrow distribution of oxygen and hydrogen isotopes (δD from -103.2 to -85.6 ‰ and δO from -15.4 to -12.9 ‰). Some of them have pronounced excursions on the isotopic composition, which indicates a difference in their genesis: from condensate to mixed with ancient infiltrogenic. The isotopic composition of carbon of water-dissolved carbon dioxide (δС from -41.6 to -16.3 ‰) indicates its biogenic origin and the possibility of interstratal flows from overlying horizons.

The Isua (Greenland) relict stromatolites cannot be confidently interpreted as original sedimentary structures

<p>The biogenicity of proposed stromatolite structures from Eoarchean (ca. 3.71 Ga) rocks of the Isua Supracrustal Belt (ISB) in West Greenland is under debate. Our 2020 publication argues against biogenicity for the proposed stromatolites. The subsequent Comment to our work challenged some of our fundamental arguments for a tectonic origin to the structures. This Comment has been an opportunity for us to elaborate on these structures and further refine and solidify our initial conclusion that they represent the expected outcome of the tectonic deformation displayed in the ISB. This dialogue between groups is essential as the consequence of these structures being biogenic would move the date for complex microbial communities 200 million years closer to Earth's formation, to a time when Earth’s surface would have been even less habitable. Here we reexamine our four key observations that support our tectonic origin. First, we report detailed field characterization and structural analysis to show that the structures are linear inverted ridges aligned with azimuths of local and regional fold axes and parallel to linear structures; they were never primary linear, deformation-parallel stromatolites or deformed conical stromatolites. Second, our combined major element (e.g., Ca, Mg, Si) scanning μXRF maps fail to reveal internal laminations for the cores of these structures, but other authors argue layers are present. In the instance where layers appear to be preserved, we argue that an amorphous core is still present.  Also, layering on its own is inconclusive of a biogenic origin as relict internal laminations could be preserved. Third, the gross morphology of these structures being nearly identical in morphology and dimensions to clearly tectonic structures only tens of meters away is a more reliable indicator of a tectonic versus biogenic origin than internal laminations. Lastly, discontinuous field relationships and absence of primary sedimentary structures that could serve as way-up indicators preclude confident assignment of these outcrops as being structurally overturned, as originally argued. Collectively, our results reinforce that the Isua structures are the expected result of a tectonic fabric that preserves no fine-scale primary sedimentary structures and were probably never stromatolites.</p>

Genesis of Graphite in Metapelites in the North-Western Border of the Lypniazhka Massif (the Inhul Domain of the Ukrainian Shield)

This study presents results of an investigation of metamorphic rocks of the Inhul-Inhulets series located in the northwestern border of the Lypniazhka granite-migmatite massif (Inhul domain, the Ukrainian Shield). The rocks were studied petrographically and mineralogically and carbon isotope, Raman spectroscopic and microprobe measurements were made. Graphite and calcite were given special attention. Metapelites and quartz-rich graphite-biotite-garnet rocks were investigated. The former consist of biotite, graphite-biotite, amphibole-bearing graphite-biotite gneisses. Graphite in them is evenly distributed through the rock groundmass. The δС13 values of graphite lie between -39.4‰ and -33.6‰ (relative to PDB). The graphite is considered to be of biogenic origin. Quartz-rich graphite-biotite-garnet rocks are less common, but they also contain graphite. The latter occurs as inclusions in the major minerals either forming clusters. Its δС13 values fall between -28.45‰ and -22.2‰ (relative to PDB). Based on the Raman spectra, carbon from the gneisses has an ordered graphite structure. The temperature of graphite crystallization was estimated to be between 554 and 630°С and corresponds to the amphibolite facies.

ORGANIC MATTER IN THERMAL WATERS OF KAMCHATKA (OXYGEN-CONTAINING COMPOUNDS)

The author represents his investigation of the oxygen-containing compounds composition in sterile steam-water mixture from wells and in high-temperature springs of the Mutnovskaya, Paratunskaya and Uzonskaya hydrothermal systems. Using gas chromatography-mass spectrometry, it has been identified 42 oxygen-containing compounds belonging to 7 homologous series. Alcohols, esters, carboxylic acids, aldehydes and ketones of biogenic origin are widely distributed in the hydrothermal systems.

Geochemical characteristics of bottom sediments of Lake Onega

The subject of this article represents results of scientific studies in 2018–2019. The studies indicate that the phenomena of gas saturation of bottom sediments are often observed within the Lake Onega. Basically, this occurs in the mouths, while in the open part of the lake the degree of gas saturation of the sediments is incomparably less. According to the geo-chemical studies, numerous signs confirmed the predominantly biogenic origin of gases.

Evidence for Biogenic Silica Occurrence in the Lower Silurian Longmaxi Shale in Southeastern Chongqing, China

The gas shale in the Lower Silurian Longmaxi Formation contains a considerable amount of biogenic silica. Various originated silicas in shale, derived from different depositional environment, are commonly associated with different degrees of organic matter enrichment, resulting in different mechanical and physical properties of shale reservoirs. Thin section identification, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), total organic carbon (TOC) analysis, X-ray diffraction (XRD) analysis, and X-ray fluorescence (XRF) spectroscopy were used to investigate the Lower Silurian Longmaxi shale from Well Yuye 1 in southeastern Chongqing, China to obtain a better understanding of the origin of silica in the Longmaxi Shale. The results show ubiquitous cryptocrystalline silicas with poorly crystalline morphology, which differs from that of the detrital silica, authigenic silica, and hydrothermal silica, proving that the cryptocrystalline silicas may have a biogenic origin. Major element and mineral composition analysis indicate no correlations between K2O/Al2O3 and SiO2/Al2O3 and between illite and SiO2, and negative correlations between TiO2 and SiO2/Al2O3, between illite and quartz and excess Si, and between Al2O3 and excess Si, and all samples being located in the area of non-hydrothermal origin in the Al-Fe-Mn diagram, excluding silicas of terrigenous detrital origin, clay mineral transformed origin, and hydrothermal origin. Moreover, the fact that almost all samples plot above the illite Si/Al line in the cross-plot of Si versus Al and the mean values of Al/(Al + Fe + Mn) and Si/(Si + Al + Fe + Ca) are close to the values of biogenic silica prove that the silicas are primarily of biogenic origin. Positive correlations between TOC and quartz and excess Si and numerous siliceous organisms are observed, indicating that the silicas are associated with siliceous organisms. The postmortem siliceous organisms underwent silica diagenesis via a dissolution-precipitation mechanism following the sequence of opal-A → opal-CT → cryptocrystalline biogenic silica as the burial depth and temperature increased.