Properties of magma at high pressures: Understanding the magma behavior in the interior of the Earth

2017 ◽  
Vol 46 (1) ◽  
pp. 30-34
Author(s):  
Tatsuya SAKAMAKI
Keyword(s):  
High Pressures ◽  
The Earth

scholarly journals The thermal conductivity of the Earth's core and implications for its thermal and compositional evolution

2020 ◽  
Author(s):  
Kenji Ohta ◽  
Kei Hirose
Keyword(s):  
Thermal Conductivity ◽  
High Pressure ◽  
Thermal History ◽  
Diamond Anvil Cell ◽  
High Pressures ◽  
Iron Alloys ◽  
Compositional Evolution ◽  
The Earth ◽  
Diamond Anvil ◽  
High Pressures And Temperatures

Abstract Precise determinations of the thermal conductivity of iron alloys at high pressures and temperatures are essential for understanding the thermal history and dynamics of the metallic cores of the Earth. We review relevant high-pressure experiments using a diamond-anvil cell and discuss implications of high core conductivity for its thermal and compositional evolution.

Review Lecture: The dynamical properties and internal structures of the Earth, the Moon and the planets

1972 ◽  
Vol 328 (1574) ◽  
pp. 301-336 ◽  
Keyword(s):  
Internal Structure ◽  
Recent Progress ◽  
High Pressures ◽  
Artificial Satellites ◽  
The Moon ◽  
The Earth ◽  
Internal Structures ◽  
Theoretical Investigations ◽  
Dynamical Properties ◽  
Very High

The aim of this review is to bring together and relate recent progress in three subjects - the internal structure of the Earth, the behaviour of materials at very high pressures and the dynamical properties of the planets. Knowledge of the internal structure of the Earth has been advanced in recent years, particularly by observations of free oscillations of the whole Earth excited by the very largest earthquakes; as a consequence, it is clear that K. E. Bullen’s hypothesis that bulk modulus is a smooth function of pressure irrespective of composition is close to the truth for the Earth. Understanding of the behaviour of materials at very high pressure has increased as a result both of experiments on the propagation of shock waves and of theoretical investigations along a number of lines and it can now be seen that Bullen’s hypothesis is not true irrespective of chemical composition and crystal structure but that it happens to apply to the Earth because of particular circumstances. Studies of the orbits of artificial satellites and space probes have led to better knowledge of the dynamics of the Moon, Mars and Venus, and there have also been recent improvements in the traditional studies of Uranus and Neptune. Our knowledge of the dynamics of the planets is on the whole rather restricted, and Bullen’s hypothesis only applies directly to the Moon (for which the application is trivial) and possibly to Mars; the dynamical properties do none the less set fairly restrictive limits to the models that can be constructed for other planets. It would be possible for all planets to have cores of similar composition to the Earth ’s, surrounded by mantles of different sorts, silicates for the terrestrial planets and mostly hydrogen for Jupiter, Saturn, Uranus and Neptune.

scholarly journals Είμαστε μόνοι στο συμπάν; Οι μετεωρίτες δίνουν απαντήσεις;

2016 ◽  
Vol 47 (1) ◽  
pp. 32
Author(s):  
Ι. Μπαζιώτης ◽  
L. A. Taylor
Keyword(s):  
High Pressures ◽  
Geochemical Data ◽  
The Moon ◽  
Martian Surface ◽  
The Earth ◽  
Past Life ◽  
Celestial Bodies ◽  
Meteorite Fall ◽  
Event Based ◽  
Moon Landing

The humankind, despite the recent technological achievements, does not yet have the ability to carry out routine trips to nearby celestial bodies. However, space science is a reality. The “Apollo” missions, that took place during the period 1969-1972, included the moon landing, the walk of astronauts and collection of valuable samples. Since then, no similar space journey has been carried out. The possibility for future missions such as the return to the Moon or Mars, or to an asteroid (e.g., Vesta), seems small enough to be implemented in the next decades. Nevertheless, nature has the mechanism and procedures to resolve this problem by sending extra-terrestrial rocks in earth in the form of meteorites. Meteorite fall on Earth is a major event, as it reveals important information about the primordial stages of formation of our solar system, or the creation processes of other planets. However, the big question still remains; whether these rocks host or have traces of past life in turn employs researchers in the last twenty years. McKay et al. (1996) studied the meteorite ALH 84001 originating from Mars, claimed for important discoveries such as structures corresponding to nanobacteria. In the current paper, we focus on the origin of Martian meteorites, presenting their complete geological history; from the genesis of their protoliths till their falling to the earth. We attempt to shade light in the understanding of meteorite formation using mineralogical-petrological-geochemical data, and the assignment of timing for each event based upon contemporary geochronological data. Recently, studies of the Martian meteorite Tissint, allegedly discovered structures rich in carbon and oxygen. Furthermore, recent field observations from Curiosity rover, indicates the existence of surface water that flowed once in the past at the Martian surface. We conclude that the planet Mars might not be a "dead" planet. But it turns out that many of the meteorites that reach the Earth, have undergone a complex history which is associated with the development of very high pressures and temperatures on the surface of the planet (e.g., Mars) from which they originate, able to destroy any trace of life before them. After all, we should be very sceptic and evaluate all the possibilities before the acceptance for the existence of life out there. 

“Shearing Phenomena at High Pressures of Possible Importance for Geology.” Journal of Geology, Vol. XLIV, pp. 653–669, 1936. By P. W. Bridgman.

Geophysics ◽  
1936 ◽  
Vol 1 (3) ◽  
pp. 379-380
Author(s):  
C. Maynard Boos
Keyword(s):  
High Pressure ◽  
Present Article ◽  
Seismic Data ◽  
High Pressures ◽  
Fundamental Constants ◽  
Shearing Stress ◽  
The Earth ◽  
Great Pressure ◽  
Produce Flow

Contributions from Bridgman’s high‐pressure laboratory at Harvard are always of interest. In the present article he discusses flow, and the shearing stresses necessary to produce flow under high pressure for a wide variety of substances. Rigidity, or the resistance to shearing stress, is one of the fundamental constants of the seismologist, and Bridgman here deals with shearing stresses under conditions of great pressure comparable to those under which seismic data are obtained. The experiments were made at room temperatures, but at pressures as high as [Formula: see text] corresponding to those prevailing at depths of 166 km. Few rocks now available for examination at the surface of the earth are likely to have been buried so deep.

The earth's mantle

1965 ◽  
Vol 55 (3) ◽  
pp. 619-625
Author(s):  
L. Don Leet ◽  
Florence J. Leet
Keyword(s):  
Plastic Deformation ◽  
Superheated Steam ◽  
High Pressures ◽  
Water Molecules ◽  
Earth’S Mantle ◽  
Primary Mechanism ◽  
The Earth ◽  
State Of Matter ◽  
Solid Liquid ◽  
Very High

Abstract It has been generally accepted for some time that the earth's mantle is “solid” (crystalline). But increasing complications arise as attempts are made to rationalize that state of matter with the growing list of properties of the mantle. We suggest that materials of the earth's mantle are in a fourth state of matter, which we propose calling soliqueous—a combination of solid, liquid, and gaseous. It includes elements for forming water molecules and allows expanding superheated steam to supply the principal force for elevating and distorting land masses. Bridgman's experiments on plastic deformation of materials at very high pressures revealed that spasmodic jerky yielding is characteristic. We propose plastic rupture in shear as the primary mechanism by which energy in the earth is converted to the vibrations of earthquakes.

The Bakerian Lecture, 1983 - The Earth’s core: its composition, formation and bearing upon the origin of the Earth

1984 ◽  
Vol 395 (1808) ◽  
pp. 1-46 ◽  
Keyword(s):  
Experimental Data ◽  
High Pressures ◽  
Solidus Temperature ◽  
Outer Core ◽  
Molten Iron ◽  
Volatile Elements ◽  
The Core ◽  
The Earth ◽  
Complete Miscibility ◽  
Abundant Element

The density of the outer core is about 3 % smaller than pure iron, which implies that the core contains a substantial amount of one or more low atomic mass elements. Candidates which have been suggested on various grounds include S, H, C, O, Si, and Mg. Plausible models of accretion of the Earth encounter difficulties in trapping sufficient S, H and C to explain the density deficit. On the other hand, entry of Si and Mg is not favoured by thermodynamic arguments. Oxygen is the most abundant element in the Earth and would be a prime candidate if it could be shown to be extensively soluble in molten iron at core temperatures and pressures. New experimental data on the solubility of FeO in molten iron are reviewed. They demonstrate that at atmospheric pressure, FeO is extensively soluble in iron at 2500 °C and that complete miscibility probably occurs above 2800 °C. Moreover, liquid iron in equilibrium with magnesiowüstite (Mg 0.8 Fe 0.2 )O also dissolves large quantities of FeO above 2800 °C. The solubility of FeO in molten iron is considerably increased by high pressures, because of the small partial molar volume of FeO in the Fe─FeO melt. If the core formed by segregation of metal originally dispersed throughout the Earth, it seems inevitable that it would have dissolved large amounts of FeO. The density of the outer core can be matched if it contains about 35 mol % FeO, a quantity that is readily explained by the new experimental data. Solution of FeO in iron causes the melting point of the metal phase to be depressed below the solidus temperature of the silicate phase assemblages in the mantle. A model for the formation of the core is described, based upon Fe-FeO phase relations at high temperatures and pressures. The model implies the presence of a high content of FeO in the Bulk Earth. This can be explained if the Earth accreted from a mixture of two components: A, a highly reduced, metal-rich devolatilized assemblage and B, a highly oxidized, volatile-rich assemblage similar to C1 chondrites. The formation of these components in the solar nebula is discussed. The large amount of FeO now inferred to be present in the Earth was mainly produced during accretion by oxidation of metallic iron from component A by water from component B. This two-component mixing model also provides an attractive explanation of some aspects of the chemistry of the Earth’s mantle including the abundances of siderophile and volatile elements.

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