Composition and conditions of the late Mesozoic volcanism occurrence of the northern part of the Borschovochny ridge (Eastern Transbaikalia)

On the basis of geochemical study results composition heterogeneity and formation conditions of late Mesozoic subvolcanic rocks from northern part of Borschovochny ridge by an example of shadoronsky and abgatuysky complexes are discussed. Obtained results show that volcanic rocks of both complexes have heterogeneous composition and differ from each other in level and other features of alkalinity. Rare and trace elements geochemistry study results show that there is a significant enrichment with LILE (Cs, Rb, Ba) and some depletion with HFSE (Nb, Ta), meanwhile the correlation between Th and Yb indicates conditions of active continental margin. Gd/Yb and La/Sm ratios allow to conclude that shadoronsky complex rocks originated from garnet-stable mantle source (partial melting of 5% of garnet peridotite), while abagatuysky complex rocks originated from transitional garnet-spinel mantle

Metasomatic alteration associated with the formation of subvolcanic rocks of the Abagatuysky complex (Nerchinsk ore region, Eastern Transbaikalia)

Within the northeastern edge of the Borschovochny pluton, located in Eastern Transbaikalia, a complex of small intrusions is localized, represented by the subvolcanic bodies of the Early Cretaceous Abagatuysky andesite-dacite complex. These intrusions, along with significant dynamometamorphic (tectonic) transformations, produced the development of metasomatic alteration, united in three large rock associations — propylites, beresites, and argillisites. These metasomatic associations successively replace each other as they move away from the center of heat exposure of intrusions. In addition, each of these groups of metasomatites has its own unique internal mineral zonality, and the most productive of them, on the subject of gold ore mineralization, is the beresite association

Composition and conditions of the late Mesozoic volcanism occurrence of the northern part of the Borschovochny ridge (Eastern Transbaikalia)

On the basis of geochemical study results composition heterogeneity and formation conditions of late Mesozoic subvolcanic rocks from northern part of Borschovochny ridge by an example of shadoronsky and abgatuysky complexes are discussed. Obtained results show that volcanic rocks of both complexes have heterogeneous composition and differ from each other in level and other features of alkalinity. Rare and trace elements geochemistry study results show that there is a significant enrichment with LILE (Cs, Rb, Ba) and some depletion with HFSE (Nb, Ta), meanwhile the correlation between Th and Yb indicates conditions of active continental margin. Gd/Yb and La/Sm ratios allow to conclude that shadoronsky complex rocks originated from garnet-stable mantle source (partial melting of 5% of garnet peridotite), while abagatuysky complex rocks originated from transitional garnet-spinel mantle

Geochemical evidence for multi-depth magma generation for Permian-Triassic dolerite and Late Cretaceous basanite of the Minusa Paleorift, Siberia

The chemical composition of alkaline (Late Cretaceous basanite) and subalkaline (Permian-Triassic dolerite) basaltoids of different ages in the northern part of the Minusa Trough was studied by optical emission spectroscopy and mass spectrometry with inductively coupled plasma. The revealed differences of subvolcanic rocks in the nature of enrichment in HFS- and LIL-elements may indicate the generation of primary magmas at different depths and small degrees of melting of garnet and spinel mantle peridotite. The model of decompression partial melting of the subcontinental lithospheric mantle under the garnet stability conditions is applicable to the formation of basanite. It is assumed that the formation of dolerite magma was due to the interaction of the melt from shallower spinel peridotite with the OIB component of the sublithospheric mantle plume

NANCY: Next-generation All-sky Near-infrared Community surveY

International audienceThe Nancy Grace Roman Space Telescope is capable of delivering an unprecedented all-sky, high-spatial resolution, multi-epoch infrared map to the astronomical community. This opportunity arises in the midst of numerous ground- and space-based surveys that will provide extensive spectroscopy and imaging together covering the entire sky (such as Rubin/LSST, Euclid, UNIONS, SPHEREx, DESI, SDSS-V, GALAH, 4MOST, WEAVE, MOONS, PFS, UVEX, NEO Surveyor, etc.). Roman can uniquely provide uniform high-spatial-resolution (~0.1 arcsec) imaging over the entire sky, vastly expanding the science reach and precision of all of these near-term and future surveys. This imaging will not only enhance other surveys, but also facilitate completely new science. By imaging the full sky over two epochs, Roman can measure the proper motions for stars across the entire Milky Way, probing 100 times fainter than Gaia out to the very edge of the Galaxy. Here, we propose NANCY: a completely public, all-sky survey that will create a high-value legacy dataset benefiting innumerable ongoing and forthcoming studies of the universe. NANCY is a pure expression of Roman's potential: it images the entire sky, at high spatial resolution, in a broad infrared bandpass that collects as many photons as possible. The majority of all ongoing astronomical surveys would benefit from incorporating observations of NANCY into their analyses, whether these surveys focus on nearby stars, the Milky Way, near-field cosmology, or the broader universe