scholarly journals Sulfide Breccias from the Semenov-3 Hydrothermal Field, Mid-Atlantic Ridge: Authigenic Mineral Formation and Trace Element Pattern

Minerals ◽  
2018 ◽  
Vol 8 (8) ◽  
pp. 321 ◽  
Author(s):  
Irina Melekestseva ◽  
Valery Maslennikov ◽  
Nataliya Safina ◽  
Paolo Nimis ◽  
Svetlana Maslennikova ◽  
...  
Keyword(s):  
Trace Elements ◽  
Hydrothermal Field ◽  
Trace Element Pattern ◽  
Modes Of Occurrence ◽  
Element Pattern ◽  
Authigenic Mineral ◽  
Mid Atlantic Ridge ◽  
Lower Temperature ◽  
Hydrothermal Sulfides

The aim of this paper is the investigation of the role of diagenesis in the transformation of clastic sulfide sediments such as sulfide breccias from the Semenov-3 hydrothermal field (Mid-Atlantic Ridge). The breccias are composed of marcasite–pyrite clasts enclosed in a barite–sulfide–quartz matrix. Primary hydrothermal sulfides occur as colloform, fine-crystalline, porous and radial marcasite–pyrite clasts with inclusions or individual clasts of chalcopyrite, sphalerite, pyrrhotite, bornite, barite and rock-forming minerals. Diagenetic processes are responsible for the formation of more diverse authigenic mineralization including framboidal, ovoidal and nodular pyrite, coarse-crystalline pyrite and marcasite, anhedral and reniform chalcopyrite, inclusions of HgS phase and pyrrhotite–sphalerite–chalcopyrite aggregates in coarse-crystalline pyrite, zoned bornite–chalcopyrite grains, specular and globular hematite, tabular barite and quartz. The early diagenetic ovoid pyrite is enriched in most trace elements in contrast to late diagenetic varieties. Authigenic lower-temperature chalcopyrite is depleted in trace elements relative to high-temperature hydrothermal ones. Trace elements have different modes of occurrence: Se is hosted in pyrite and chalcopyrite; Tl is related to sphalerite and galena nanoinclusions; Au is associated with galena; As in pyrite is lattice-bound, whereas in chalcopyrite it is related to tetrahedrite–tennantite nanoinclusions; Cd in pyrite is hosted in sphalerite inclusions; Cd in chalcopyrite forms its own mineral; Co and Ni are hosted in chalcopyrite.

Covellite of the Semenov-2 hydrothermal field (13°31.13′ N, Mid-Atlantic Ridge): Enrichment in trace elements according to LA ICP MS analysis

2017 ◽  
Vol 473 (1) ◽  
pp. 291-295 ◽  
Author(s):  
I. Yu. Melekestseva ◽  
V. V. Maslennikov ◽  
S. P. Maslennikova ◽  
L. V. Danyushevsky ◽  
R. Large
Keyword(s):  
Trace Elements ◽  
Hydrothermal Field ◽  
Ms Analysis ◽  
Icp Ms ◽  
Mid Atlantic Ridge

Distribution of trace elements in sulfides from Deyin hydrothermal field, Mid-Atlantic Ridge – Implications for its mineralizing processes

2021 ◽  
Vol 128 ◽  
pp. 103911
Author(s):  
Yaqun Ren ◽  
Cora C. Wohlgemuth-Ueberwasser ◽  
Fei Huang ◽  
Xuefa Shi ◽  
Bing Li ◽  
...  
Keyword(s):  
Trace Elements ◽  
Hydrothermal Field ◽  
Mid Atlantic Ridge ◽  
Distribution Of Trace Elements

The Role of Afamin and Other Trace Elements in the Prediction of GDM: a Tertiary Center Experience

2021 ◽  
Author(s):  
Hasan Eroğlu ◽  
Gökçen Örgül ◽  
Nazan Vanlı Tonyalı ◽  
Derya Biriken ◽  
Naci Polat ◽  
...  
Keyword(s):  
Trace Elements ◽  
Tertiary Center

scholarly journals Geochemical Fractions of Heavy Metals in Bottom Sediments of the Pobeda Hydrothermal Field, Mid-Atlantic Ridge (17°07′–17°08′ N)

2021 ◽  
Vol 6 (1) ◽  
pp. 14
Author(s):  
Liudmila Demina ◽  
Irina Gablina ◽  
Olga Dara ◽  
Dmitry Budko ◽  
Nina Gorkova ◽  
...  
Keyword(s):  
Total Content ◽  
Element Distribution ◽  
Hydrothermal Field ◽  
Residual Fraction ◽  
Carbonate Sediments ◽  
Metalliferous Sediments ◽  
Geochemical Fractions ◽  
Metalliferous Sediment ◽  
Fe And Mn ◽  
Mid Atlantic Ridge

We examined the distribution of Fe, Mn, Cu, Zn, and Pb in one core of metalliferous, and one core of non-mineralized (background) carbonate sediments (located 69 km northwards), from the Pobeda hydrothermal field. Mechanisms of metal accumulation in sediments (12 samples) were evaluated based on sequential extraction of geochemical fractions, including mobile (exchangeable complex, authigenic Fe-Mn hydroxides, and sulfides), and lithogenic (fixed in crystalline lattices) forms. Maps of element distribution in sediment components were obtained using a scanning electron microscope equipped with an energy-dispersive spectrometry detector. In metalliferous sediments, according to X-ray diffraction data, the main Fe mineral phase was goethite FeOOH (37–44% on a carbonate-free basis). The contents of Fe and Mn reached 31.6 and 0.18%, respectively, whereas concentrations of Cu, Zn and Pb were 0.98, 0.36, and 0.059%. The coefficient of metal enrichment relative to background values varied from 16 to 125 times. The exception was Mn, for which no increased accumulation was recorded. Essential mass of Fe (up to 70% of total content) was represented by the residual fraction composed of crystallized goethite, aluminosilicates, the minerals derived from bedrock destruction processes. Among geochemically mobile fractions, 90–97% of total Fe was found in the form of authigenic oxyhydroxides. The same fraction was the predominant host for Mn in both metalliferous and background sediments (55–85%). A total of 40–96 % of Cd, Cu, Zn, and Pb were associated with these Fe and Mn fractions. The sulfide fraction amounted to roughly 10% of each metal. In metalliferous sediment core, the maximum concentrations of metals and their geochemically mobile fractions were recorded in deeper core intercepts, an observation that might be attributed to influence of hydrothermal diffused fluids. Our data suggested that metals are mostly accumulated in carbonate sediments in their contact zone with the underlying serpentinized basalts.

scholarly journals Trace Elements as Immunoregulators in SARS-CoV-2 and Other Viral Infections

2021 ◽  
Author(s):  
Karthick Dharmalingam ◽  
Amandeep Birdi ◽  
Sojit Tomo ◽  
Karli Sreenivasulu ◽  
Jaykaran Charan ◽  
...  
Keyword(s):  
Immune Response ◽  
Trace Elements ◽  
Viral Entry ◽  
Viral Infections ◽  
Inhibitory Effect ◽  
Antioxidants Activity ◽  
Host Immune Responses ◽  
Complex Interactions ◽  
Downstream Processes

AbstractNutritional deficiency is associated with impaired immunity and increased susceptibility to infections. The complex interactions of trace elements with the macromolecules trigger the effective immune response against the viral diseases. The outcome of various viral infections along with susceptibility is affected by trace elements such as zinc, selenium, iron, copper, etc. due to their immuno-modulatory effects. Available electronic databases have been comprehensively searched for articles published with full text available and with the key words “Trace elements”, “COVID-19”, “Viral Infections” and “Immune Response” (i.e. separately Zn, Se, Fe, Cu, Mn, Mo, Cr, Li, Ni, Co) appearing in the title and abstract. On the basis of available articles we have explored the role of trace elements in viral infections with special reference to COVID-19 and their interactions with the immune system. Zinc, selenium and other trace elements are vital to triggerTH1 cells and cytokine-mediated immune response for substantial production of proinflammatory cytokines. The antiviral activity of some trace elements is attributed to their inhibitory effect on viral entry, replication and other downstream processes. Trace elements having antioxidants activity not only regulate host immune responses, but also modify the viral genome. Adequate dietary intake of trace elements is essential for activation, development, differentiation and numerous functions.

scholarly journals Potential Role of Trace Elements (Al, Cu, Zn, and Se) in Multiple Sclerosis Physiopathology

2020 ◽  
Vol 27 (4) ◽  
pp. 163-177
Author(s):  
Mohammad Sadegh Hesamian ◽  
Nahid Eskandari
Keyword(s):  
Multiple Sclerosis ◽  
T Cells ◽  
Trace Elements ◽  
Plasma Cells ◽  
Peripheral Tolerance ◽  
The Central Nervous System ◽  
Living Organisms ◽  
Tolerance Breakdown ◽  
Peripheral Immune Cells

Multiple sclerosis (MS) is an unpredictable disease of the central nervous system. The cause of MS is not known completely, and pathology is specified by involved demyelinated areas in the white and gray matter of the brain and spinal cord. Inflammation and peripheral tolerance breakdown due to Treg cell defects and/or effector cell resistance are present at all stages of the disease. Several invading peripheral immune cells are included in the process of the disease such as macrophages, CD8+ T cells, CD4+ T cells, B cells, and plasma cells. Trace elements are known as elements found in soil, plants, and living organisms in small quantities. Some of them (e.g., Al, Cu, Zn, Mn, and Se) are essential for the body’s functions like catalysts in enzyme systems, energy metabolism, etc. Al toxicity and Cu, Zn, and Se toxicity and deficiency can affect the immune system and following neuron inflammation and degeneration. These processes may result in MS pathology. Of course, factors such as lifestyle, environment, and industrialization can affect levels of trace elements in the human body.

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