High-pressure minerals

2019 ◽  
Vol 104 (12) ◽  
pp. 1701-1731 ◽  
Author(s):  
Oliver Tschauner
Keyword(s):  
High Pressure ◽  
Upper Mantle ◽  
Chemical Elements ◽  
Earth Pressure ◽  
Chemical Components ◽  
The Past ◽  
The Earth ◽  
Deep Earth ◽  
Definition Of ◽  
Physical Reasons

Abstract This article is dedicated to the occurrence, relevance, and structure of minerals whose formation involves high pressure. This includes minerals that occur in the interior of the Earth as well as minerals that are found in shock-metamorphized meteorites and terrestrial impactites. I discuss the chemical and physical reasons that render the definition of high-pressure minerals meaningful, in distinction from minerals that occur under surface-near conditions on Earth or at high temperatures in space or on Earth. Pressure-induced structural transformations in rock-forming minerals define the basic divisions of Earth's mantle in the upper mantle, transition zone, and lower mantle. Moreover, the solubility of minor chemical components in these minerals and the occurrence of accessory phases are influential in mixing and segregating chemical elements in Earth as an evolving planet. Brief descriptions of the currently known high-pressure minerals are presented. Over the past 10 years more high-pressure minerals have been discovered than during the previous 50 years, based on the list of minerals accepted by the IMA. The previously unexpected richness in distinct high-pressure mineral species allows for assessment of differentiation processes in the deep Earth.

Multiple dichotomies of the Anthropocene

2016 ◽  
Vol 3 (3) ◽  
pp. 218-230 ◽  
Author(s):  
Whitney J Autin
Keyword(s):  
Popular Culture ◽  
Human Interaction ◽  
Modern Literature ◽  
Formal Definition ◽  
Earth System ◽  
Geological Time ◽  
The Past ◽  
The Earth ◽  
Definition Of ◽  
System Benefit

Anthropocene has developed a varied set of connotations among scientific and non-scientific advocates. As a result, multiple dichotomies of the Anthropocene exist within various scholarly disciplines. The Anthropocene allows people to reinforce and perpetuate preferred views about the implications of human interaction with the Earth System as our management of the environment is called into question. Scientific dichotomies arise from opinions about the need for formal or informal definition and the recognition of a modern versus historical onset of the Anthropocene. Philosophical dichotomies center around good versus dystopian outcomes of Anthropocene and whether or not humanity is part of what historically has been called nature. Political dichotomies insert Anthropocene into classic conservative versus liberal arguments. Artistic dichotomies tend to evaluate the effects of technology on modernism by embracing a nostalgia for the past or projecting an apocalyptic future. Multiple dichotomies drive conversation towards confusion as individuals argue preferred versions of an Anthropocene concept. Philosophical and political perspectives are affecting scientific views of proposed geological time markers for the start of the Anthropocene as conceptual ideologies appear to compete with tangible stratigraphic attributes. Formal definition of the Anthropocene has potential to inhibit popular usage and further confuse an already confused media. Informal stratigraphic usage by scientists and an open-ended view among non-scientific proponents may be the best approach to formulate a robust Anthropocene message. Both humanity and the Earth System benefit from a dynamic tag line that enhances environmental awareness and provides opportunity to modify our habits of resource overuse and ecosystem neglect. Concepts and imagery offered in the form of modern literature and art have the greatest prospect of affecting popular culture perspectives of the Anthropocene’s role in environmental debate.

The concept of cluster evolution minerageny in the Earth’s history

2018 ◽  
pp. 3-17
Author(s):  
V. A. Krivitsky ◽  
V. I. Starostin
Keyword(s):  
Nuclear Matter ◽  
Upper Mantle ◽  
Chemical Elements ◽  
Superheavy Elements ◽  
Stellar Matter ◽  
Cluster Evolution ◽  
The Earth ◽  
Plume Flows

The new concept of cluster evolutionary mineralogy is based on the idea of the formation of the Earth from the primary stellar matter, which was preserved in the cores of the planets. The consequent destruction of it, as a result of the decay of heavy nuclear matter, leads to fragmentation of the substance until the appearance of superheavy elements with their further nuclear dissociation. As a result, a protomagma emerges, which enters the upper mantle in the form of plume flows. This process supports the reactions that result in the formation of chemical elements, minerals, ores and rocks, from which the upper mantle and the crust are formed. The processes of nuclear dissociation lead to the release of energy and the decomposition of matter, which initiates the growth of the earth's volume, its geotectonic activity, and the appearance of the hydrosphere and the atmosphere.

5. Rocks in the deep

2016 ◽  
pp. 66-79
Author(s):  
Jan Zalasiewicz
Keyword(s):  
Magnetic Fields ◽  
Upper Mantle ◽  
Lower Crust ◽  
Seismic Waves ◽  
Direct Experience ◽  
Rock Fragments ◽  
The Core ◽  
The Earth ◽  
Deep Earth ◽  
Volcanic Processes

It is over 6,000 km to the centre of the Earth, but our direct experience of its rocks goes to little more than 3 km below the surface in the deepest mines on Earth. ‘Rocks in the deep’ shows that we can find out more by assessing rock fragments brought from deeper levels by tectonic or volcanic processes; by analysing patterns of change in the gravitational and magnetic fields; by detecting seismic waves that have travelled through the Earth; or by recreating conditions of the deep Earth in the laboratory. It describes what is known about the lower crust, the upper mantle, the deep mantle, and the core.

Behavior of hydrogen defects in olivine at high temperature and high pressure: disordering, re-configuration and interation

2020 ◽  
Author(s):  
Yan Yang ◽  
Qunke Xia
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Hydrogen Storage ◽  
Upper Mantle ◽  
Water Distribution ◽  
Chemical Compositions ◽  
Ambient Conditions ◽  
Deep Earth ◽  
Hydrogen Defects ◽  
Natural Olivine

<p>Water in the form of hydrogen defects in olivine strongly influences the physical properties of olivine, thereby being responsible for physical/chemical processes in the deep Earth. Knowledge of hydrogen defects in olivine is fundamental to understand water distribution and its impact on the upper mantle. However, the current explanations of water effects on processes in the deep Earth are mainly based on hydrogen defects observed at ambient conditions. Since hydrogen is highly mobile, the migration of hydrogen between lattice sites at high temperature and high pressure may not be quenchable. Therefore, there arises a question: whether the hydrogen defects in olivine obtained from infrared spectra at ambient conditions are the same as those at the temperature and pressure conditions of the upper mantle? Here, we carry out <em>in situ</em> high-temperature and high-pressure infrared spectroscopic investigations on hydrogen defects in the natural olivine and synthetic Fe-free forsterite. We find that hydrogen defects exhibit disordering at temperature-pressure conditions of the upper mantle, and hydrogen defects corresponding to pure Si vacancies display re-configuration under compression. Interestingly, dehydrogenation experiments of the natural olivine indicate interactions of hydrogen defects. The lost hydrogen of the titanium-clinohumite defects does not completely release out of the crystal. It can migrate to pure Si vacancies and, also, can move to Mg vacancies coupling with trivalent cations. Thus, dehydrogenation and interactions of hydrogen storage sites may be very complex. There may be other reactions among storage sites during dehydrogenation, depending on the chemical compositions, hydrogen storage sites, and the annealing conditions. In conclusion, we report disordering and reconfiguration of hydrogen storage sites at high temperature and high pressure, and also interactions of hydrogen storage sites during dehydrogenation. These are vital for understanding water distribution and processes in the deep Earth.</p>

Heidegger, Aristotle, and the Future of Art

2016 ◽  
Vol 50 ◽  
pp. 57-70
Author(s):  
Khafiz Kerimov ◽  
Keyword(s):  
Nicomachean Ethics ◽  
Human Beings ◽  
Work Of Art ◽  
The Past ◽  
The Earth ◽  
The Future ◽  
Self Knowledge ◽  
The Creation ◽  
Definition Of

The epilogue of Martin Heidegger's Der Ursprung des Kunstwerkes quotes Hegel's famous judgment: “[A]rt is and remains for us, on the side of its highest vocation, something past.” With this judgment, Hegel says that art has ceased to be the vehicle of self-knowledge for human beings; Hegel proclaims the pastness of art. But the future of art is thus put into question. This is how Heidegger transforms Hegel's verdict into a question: “Is art still an essential and necessary way in which […] truth happens which is decisive for our historical existence, or is art no longer of this character?” Thus, the question of the pastness of art turns into the question regarding whether art is to be or not to be, into the question of the future of art. Hegel's judgment proclaims the pastness of art, because art is implicated with material contingency. That means that the question of the rehabilitation of art, of the future of art, is at the same time the question of the phenomenological rehabilitation of the material. What is central to this project of rehabilitation is the figure of the work of art with its own peculiar kind of materiality. Therefore, Heidegger reformulates the material of art as earth which is a source not just of contingency but also of potentiality. Yet, Heidegger does not understand art as the creation of aesthetic objects, rather, art is concerned with ποίησιϛ, with the bringing forth of beings out of the unconcealment. Such is the formulaic definition of art as τέχνη in Aristotle's Nicomachean Ethics: “All art is concerned with the process of coming into being, and to practice art is also to consider how something capable of being or not being [τι τῶν ἐνδεχομένων καὶ εἶναι καὶ μὴ εἶναι] […] may come into being.” This formula, although it is nowhere present in the essay, is the hidden center of Heidegger's Der Ursprung des Kunstwerkes – such is the claim of this essay. Heidegger returns to the ancient definition of τέχνη to place art within the parameters of history, i.e., starting history anew by introducing new beings. But every bringing forth of beings is a retrieval of the past, i.e., of the earth rich with potentiality from which alone the future can unfold. Thus, every decision concerning the future always takes up the past, i.e., the already-there of the earth.

A Discussion on volcanism and the structure of the Earth - Introductory remarks

1972 ◽  
Vol 271 (1213) ◽  
pp. 103-103 ◽  
Keyword(s):  
Upper Mantle ◽  
Royal Society ◽  
Volcanic Rocks ◽  
Direct Methods ◽  
Continental Margins ◽  
Island Arcs ◽  
Research Committee ◽  
The Past ◽  
The Earth ◽  
Oceanic Rocks

Although volcanoes provide some of nature’s most spectacular phenomena, and have been the objects of record since the earliest days of science, the accumulation of data in the past 150 years has until very recently only served to emphasize the extent of their unknown characteristics. In the last decade however there have been notable advances, both in the observation of volcanoes and volcanic rocks, and in the spectacular development of ideas about the mobility of the crust that enable volcanicity to be related to the structure of the Earth. These ideas led the Volcanic Studies Group of the Geological Society of London, and the Volcanological Research Committee of the Royal Society to consider holding a symposium to take stock of the position in the year that the Upper IVIantle Project was scheduled to end. The meeting, arranged principally to consider Tertiary and Recent volcanic rocks, fell into four groups of papers which generally coincided with the half-day sessions: oceanic rocks (Chairman, Professor J. Sutton, F.R.S.); island-arcs and continental margins (Chairman, Professor W. A. Deer, F.R.S.); and continental volcanicity (Chairmen, Professor F. H. Stewart, F.R.S. and Professor K. C. Dunham, F.R.S.). Included in the last session were papers dealing with the evidence from the only direct methods of investigation of the Upper Mantle, plutonic xenoliths and the kimberlites, and some of the papers that quantify the chemistry and kinematics of volcanicity.

scholarly journals WANDERING ABOUT MINERALOGY AND PETROLOGY

2017 ◽  
Vol 43 (1) ◽  
pp. 247
Author(s):  
Ch. Katagas
Keyword(s):  
Experimental Methods ◽  
Rapid Expansion ◽  
Ion Microprobe ◽  
The Past ◽  
Societal Challenges ◽  
The Earth ◽  
Icp Ms ◽  
Deep Earth ◽  
Xrd Techniques ◽  
Available Information

Over the past few years an intense amount of research on various themes stimulated the development of Mineralogy and all its diversity, and many exciting discoveries have been made. New or technologically developed analytical and experimental methods such as ion microprobe, powerful MAS NMR, LA-ICP-MS, IR, Raman, XAS spectroscopies, beams of high intensity, Synchrotron radiation that enhanced the sensitivity of conventional spectroscopic and XRD techniques, beams of neutrons, widely available information and tremendous computing and modelling facilities have turned out to be excellent tools, promoting the ability of mineralogy in solving global and societal challenges. Mineralogy today offers insights into important scientific issues, including sustainable development, evolution of the Earth and origins of life, deep Earth processes, physics and chemistry of Earth materials, fluids, magmas, igneous rocks and time scales, archaeomineralogy, nano-, geo-, and bio- environmental sciences. The mineralogical sciences today are going through a period of rapid expansion and diversification and this trend is going to continue in future. There is now great potential for much interesting work in the latter areas but also the need to somehow protect the coherence of our discipline.

The Origin of the Moon and its Relationship to the Origin of the Solar System

1962 ◽  
Vol 14 ◽  
pp. 133-148 ◽  
Author(s):  
Harold C. Urey
Keyword(s):  
Solar System ◽  
The Moon ◽  
The Past ◽  
The Earth ◽  
Short Period ◽  
Origin Of The Moon

During the last 10 years, the writer has presented evidence indicating that the Moon was captured by the Earth and that the large collisions with its surface occurred within a surprisingly short period of time. These observations have been a continuous preoccupation during the past years and some explanation that seemed physically possible and reasonably probable has been sought.

Immunoferritin localization of intracellular antigens in positively stained frozen sections

1978 ◽  
Vol 36 (2) ◽  
pp. 168-169
Author(s):  
K. T. Tokuyasu
Keyword(s):  
Surface Tension ◽  
Water Surface ◽  
Thin Layers ◽  
The Other ◽  
Positive Staining ◽  
Frozen Sections ◽  
The Past ◽  
Ultrathin Frozen Sections ◽  
Definition Of

During the past investigations of immunoferritin localization of intracellular antigens in ultrathin frozen sections, we found that the degree of negative staining required to delineate u1trastructural details was often too dense for the recognition of ferritin particles. The quality of positive staining of ultrathin frozen sections, on the other hand, has generally been far inferior to that attainable in conventional plastic embedded sections, particularly in the definition of membranes. As we discussed before, a main cause of this difficulty seemed to be the vulnerability of frozen sections to the damaging effects of air-water surface tension at the time of drying of the sections.Indeed, we found that the quality of positive staining is greatly improved when positively stained frozen sections are protected against the effects of surface tension by embedding them in thin layers of mechanically stable materials at the time of drying (unpublished).

How SIMS microscopy can be used in medicine

1992 ◽  
Vol 50 (2) ◽  
pp. 1602-1603
Author(s):  
Philippe Fragu
Keyword(s):  
Mass Spectrometry ◽  
Biomedical Applications ◽  
Secondary Ion Mass Spectrometry ◽  
Chemical Elements ◽  
Biological Applications ◽  
The Past ◽  
Potential Source ◽  
Secondary Ion ◽  
Chemical Integrity ◽  
Scientific Endeavour

The identification, localization and quantification of intracellular chemical elements is an area of scientific endeavour which has not ceased to develop over the past 30 years. Secondary Ion Mass Spectrometry (SIMS) microscopy is widely used for elemental localization problems in geochemistry, metallurgy and electronics. Although the first commercial instruments were available in 1968, biological applications have been gradual as investigators have systematically examined the potential source of artefacts inherent in the method and sought to develop strategies for the analysis of soft biological material with a lateral resolution equivalent to that of the light microscope. In 1992, the prospects offered by this technique are even more encouraging as prototypes of new ion probes appear capable of achieving the ultimate goal, namely the quantitative analysis of micron and submicron regions. The purpose of this review is to underline the requirements for biomedical applications of SIMS microscopy.Sample preparation methodology should preserve both the structural and the chemical integrity of the tissue.

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