ROLE OF ORE MAGMAS IN THE FORMATION OF DEPOSITS

2021 ◽  
pp. 84-91
Author(s):  
S. S. Dolgushin ◽  
◽  
A. P. Dolgushin ◽  
◽  
Keyword(s):  
Hydrothermal Solutions ◽  
Hydrothermal Deposits ◽  
Decisive Importance ◽  
Host Rocks

Notions are substantiated that for a certain group of so-called hydrothermal deposits, not regular lowconcentration hydrothermal solutions, including their more concentrated derivatives, colloids, are not of decisive importance in their formation, but highly concentrated magmatic systems – ore magmas forming deposits by intrusive way, at a time when hydrothermal (including gas-hydrothermal) solutions coexisting with them, being more mobile and chemically active, produce only metasomatic changes in the host rocks and wallrock dissemination, masking the magmatic nature of deposits.

Flatworm asexual multiplication implicates stem cells and regeneration

2004 ◽  
Vol 82 (2) ◽  
pp. 334-356 ◽  
Author(s):  
Maria Reuter ◽  
Natalia Kreshchenko
Keyword(s):  
Stem Cells ◽  
Pluripotent Stem Cells ◽  
Early Stage ◽  
Gradient System ◽  
Decisive Importance ◽  
Present Information ◽  
Asexual Multiplication ◽  
Primitive Feature ◽  
Head Regeneration

The phenomenon of asexual multiplication is rare in the animal kingdom, but it occurs in all main flatworm taxa. In the present paper, we review data regarding the presence of different forms of asexual multiplication in flatworms and argue that the presence of a population of totipotent or pluripotent stem cells, "neoblasts", is a primitive feature of decisive importance for the developing potential of flatworms. Next we present information on the role of stem cells in fission, head regeneration, and pharynx regeneration of planarians. Furthermore, the tracing of neoblasts in lower flatworms and cestodes is presented, and the results indicating heterogeneity of the neoblast pool are discussed. Finally, the mode by which the neoblasts are stimulated to divide, migrate, and differentiate and the nature of the interactions are discussed. We focus on (i) biogenic amines and neuropeptides, (ii) the role of neuropeptides in the early stage of regeneration, (iii) the evidence for the influences of growth factors and nitric oxide, and (iv) the influence of weak electromagnetic fields. We discuss the pattern in which a gradient system of morphogens and (or) a hierarchical system of inductions is expressed in development.

Granite petrogenesis in the Gander Zone, NE Newfoundland: mixing of melts from multiple sources and the role of lithospheric delamination

2000 ◽  
Vol 37 (4) ◽  
pp. 535-547 ◽  
Author(s):  
David I Schofield ◽  
Richard S D'Lemos
Keyword(s):  
Magma Mixing ◽  
Mobile Belt ◽  
Multiple Sources ◽  
Potential Source ◽  
Iapetus Ocean ◽  
Granite Magmatism ◽  
Host Rocks ◽  
Binary Mixing ◽  
Lower Crustal

Silurian to Devonian granites within the Gander Zone of the Appalachian Central Mobile Belt in northeastern Newfoundland formed adjacent to the former Gondwanan continental margin following terminal closure of the Iapetus Ocean. Comparison of geochemical and isotopic characteristics of the granites with their host migmatites and metasediments, amphibolite, and orthogneiss constrain their potential source. Nd and Sr isotopic compositions indicate that no single source or binary mixing product could have produced the granites. Instead, we show that they result from multicomponent mixing involving a contribution from unexposed crystalline basement, mantle or underplate, and variable contamination by supracrustal host rocks. The timing and composition of granite magmatism do not exhibit collisional orogenic, subduction-related, or continental rifting characteristics. Hence, we relate magmatism to lithospheric melting following delamination of an orogenic keel. This process provides the influx of mantle-derived magma into fertile crust and hence promotes lower crustal melting and primary magma mixing.

scholarly journals Study of Petrogenesis and Tectonomagmatic Environments of Eocene Calc-Alkaline Volcanic Units in South and Southeast of Beroni Village in Southwest Ardestan (Isfahan)

2015 ◽  
Vol 10 (Special-Issue1) ◽  
pp. 719-726
Author(s):  
Sayyed Roshan ◽  
Ali Khan Nasr Esfahani
Keyword(s):  
Volcanic Rocks ◽  
Crustal Contamination ◽  
Hydrothermal Solution ◽  
Hydrothermal Solutions ◽  
Calc Alkaline ◽  
Silica Rocks ◽  
Calcium Magnesium ◽  
Alkaline Magmas ◽  
Host Rocks ◽  
Lateral Segregation

The study area is located in south and southeast of Beroni Village. It contains volcanic rocks including andesitic-basaltic, pyroxene-bearing andesite, andesite, dacite, rhyodacite, rhyolites and Eocene-Oligocene ignimbrites. The volcanic rocks are cut by an intrusive mass with great spreading in the region. According to lithological studies, the calc-alkaline magmas in continental margin arcs are comprised of mantle and fluid crust. The basic elements in the volcanic rocks were studied in terms of petrological indices. According to the results, the metaluminous rocks underwent crustal contamination. Due to chemical reactions between the hydrothermal solution and volcanic host rocks, hydrothermal solutions in volcanic rocks penetrate the surrounding silica rocks and thus some elements such as zinc and barium diffuse in the rocks. In addition, calcium, magnesium and iron have been drawn inwards from the surrounding rocks causing lateral segregation.

The epistolary heritage of Leo Tolstoy at the turn of the XIX–XX centuries: the motive of reading in the estate

2021 ◽  
Vol 1 (6) ◽  
pp. 80-90
Author(s):  
Valeria G. Andreeva ◽  
Keyword(s):  
Spiritual Growth ◽  
Turn Of The Century ◽  
Leo Tolstoy ◽  
Moral Formation ◽  
Home Reading ◽  
Decisive Importance ◽  
Literary Process ◽  
Energy Center

Based on the analysis of the letters of Leo Tolstoy 1890–1910 the article analyzes the motive for reading, which is directly related to the estate life. The epistolary heritage of the writer has not yet been fully investigated, and in the study of the estate theme in the work of the late Tolstoy, it plays an important role. Typical for the late XIX — early XX centuries the process of impoverishment of noble estates at this time almost did not touch Yasnaya Polyana. While Tolstoy was alive, his estate remained a kind of energy center. Tolstoy's statements about the works he read in letters make it possible to estimate the volume of his reading, the literature he preferred. The author of the article selected illustrative examples from Tolstoy’s letters with a polar assessment of the works of various writers. The author analyzes the direct messages of the writer about reading as a pastime, hobby, realized mainly in letters to close people: stories about home reading, about the impressions of books. Special attention is paid to reading as the basis for the moral formation of a person and his spiritual growth, as well as the choice of books, the study of which was of decisive importance for the further course of Tolstoy's thought and the direction of his artistic and journalistic work. The article comprehends the role of Tolstoy as a key figure in the literary process at the turn of the century, evaluates its manifestations in the writer’s epistolary heritage.

Demand vs. Supply in the Industrial Revolution

1977 ◽  
Vol 37 (4) ◽  
pp. 981-1008 ◽  
Author(s):  
Joel Mokyr
Keyword(s):  
Technological Change ◽  
Western Europe ◽  
Industrial Revolution ◽  
Induced Technological Change ◽  
Decisive Importance

It has been widely believed that demand elements, jointly with supply shifts, were crucial in determining the timing, location, and general characteristics of the Industrial Revolution in England and Continental Western Europe. The possible forms which the role of demand might have taken are specified and examined both theoretically and empirically. While demand factors cannot be ruled out altogether, they were definitely of a secondary order of importance. Neither exogenous increases in the demand for manufactures, nor induced technological change are likely to have been a factor of decisive importance. A macroeconomic interpretation of the “demand hypothesis” is examined and rejected.

scholarly journals Mineral composition of host sediments influences the fossilization of soft tissues

2018 ◽  
Vol 55 (11) ◽  
pp. 1271-1283 ◽  
Author(s):  
Elena Naimark ◽  
Maria Kalinina ◽  
Alexander Shokurov ◽  
Alexander Markov ◽  
Liubov Zaytseva ◽  
...  
Keyword(s):  
Soft Tissues ◽  
Mineralogical Composition ◽  
Artemia Salina ◽  
New Mineral ◽  
X Ray ◽  
Mineral Phases ◽  
Long Term Experiments ◽  
Host Rocks

Cambrian Lagerstätten host rocks are frequently composed of kaolinite and chlorite in varying amounts; accordingly, our goal was to study the preservation potential of crustaceans in these two clays. We conducted long-term experiments (12–18 months, the longest duration of actualistic taphonomy experiments from published literature) on the decay of Artemia salina in these clay sediments. The degree of preservation, transformed mineralogical composition of the sediments, and the elemental composition of the nauplial remains were examined. We demonstrate that the kaolinite and chlorite sediment enhanced the preservation (in the kaolinite the effect was considerably higher than in the chlorite) compared with the sediment-free control. pH inside the sediments dropped to 6.5–7.1 and was even lower (<4) around the buried carcasses, facilitating the dissolution of clays. This phenomenon was confirmed by mineralogical analyses of the experimental sediments, which showed mineralogical signatures of such dissolution and new mineral phases. According to the variations in the dissolved minerals in the sediments, different cations entered the buried remains as was shown by the multiple energy dispersive X-ray analyses. An increased level of Mg was detected in the carcasses buried in chlorite, whereas Al and Si concentrations were higher in the kaolinite; in both cases, Ca rapidly entered the decaying tissues from marine water. Bacteria underwent similar mineralization as the macroremains and apparently had no direct effect on the mineralization. The results confirmed an important role of dissolved Al ions in preservation of soft-bodied organisms in clay-dominated sediments and explained wide variation in chemical composition of their fossils.

scholarly journals Efficiency of the Quality of Work of the Head in the Conditions of Market Relations

2021 ◽  
Vol 7 (2) ◽  
pp. 237-244
Author(s):  
Sh. Zainutdinov ◽  
R. Nurimbetov ◽  
A. Ismailov
Keyword(s):  
Production Management ◽  
Production Efficiency ◽  
Quality Of Work ◽  
Industrial Enterprises ◽  
Decisive Importance ◽  
Management Staff ◽  
Market Relations

In the conditions of market relations, the work of the management staff of industrial enterprises is of decisive importance. And ultimately, production efficiency depends on the quality of the manager's work. This article discusses the basic requirements of the manager, the place and role of the manager in production management, the performance of functional duties, the manager's responsibility for ensuring production efficiency, etc.

The phenomenon of Vladimir Tlostanov in the history and development processes of KBSU

2021 ◽  
Vol 21 (1) ◽  
pp. 52-63
Author(s):  
Х.Г. Тхагапсоев ◽  
Keyword(s):  
Personality Factor ◽  
Political Processes ◽  
Research Institutes ◽  
Decisive Importance ◽  
Development Institutions ◽  
Development Processes ◽  
Complex Forms

The article argues that the personality factor is of decisive importance not only in complex forms of creativity and political processes, but also in the management of development institutions – universities, corporations, research institutes. From these positions, the role of Vladimir Tlostanov in the development of KBSU is interpreted.

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