Geophysical studies on the evolution of the earth 's deep interior. Phys. Earth Planet. Inter.

1972 ◽  
Vol 15 (4) ◽  
pp. 340
Author(s):  
Donald L. Turcotte
Keyword(s):  
Earth Planet ◽  
The Earth ◽  
Deep Interior

Thermal consequences of impact bombardments to silicate crusts of terrestrial-type exoplanets

2021 ◽  
Author(s):  
Stephen J. Mojzsis ◽  
Oleg Abramov
Keyword(s):  
Extrasolar Planets ◽  
Unit Area ◽  
Production Functions ◽  
Asteroid Belt ◽  
Earth Planet ◽  
Cross Sectional ◽  
The Earth ◽  
Main Asteroid Belt ◽  
Gravitational Compression ◽  
Impactor Velocity

<p><strong>Introduction. </strong>Post-accretionary impact bombardment is part of planet formation and leads to localized, regional [e.g., 1-3], or even wholesale global melting of silicate crust [e.g., 4]; less intense bombardment can also create hydrothermal oases favorable for life [e.g, 5]. Here, we generalize the effects of late accretion bombardments to extrasolar planets of different masses (0.1-10M<sub>⊕</sub>). One example is Proxima Centauri b, estimated at ~2× M<sub>⊕</sub> [6]. We model a 0.1M<sub>⊕ </sub>“mini-Earth”<sub></sub>and “super-Earth” at 10M<sub>⊕</sub>, the approximate upper limit for a “mini-Neptune” [7]. Output predicts lithospheric melting and subsurface habitable volumes.</p><p><strong>Methods. </strong>The model [1,2] consists of (i) stochastic cratering; (ii) analytical thermal expressions for each crater [e.g., 8,9]; and (iii) a 3-D thermal model of the lithosphere, where craters cool by conduction and radiation.</p><p>We analyze impact bombardments using our solar system’s mass production functions for the first 500 Myr [10]. Surface temperatures and geothermal gradients are set to 20 °C and 70 °C/km [2]. Total delivered mass for Earth is 7.8 × 10<sup>21</sup> kg, and scaled to other planets based on cross-sectional areas, with 1.7 × 10<sup>21</sup> kg for mini-Earth, 1.2 × 10<sup>22</sup> kg for Proxima Centauri b, and 3.6 × 10<sup>22</sup> kg for super-Earth. The impactors' SFD is based on our main asteroid belt [11]. Impactor and target densities are set to 3000 kg m<sup>-3</sup> and planetary bulk densities are assumed to be 5510 kg m<sup>-3</sup>, omitting gravitational compression [7]. Impactor velocity was estimated at 1.5 × v<sub>esc</sub> for each planet, with 7.8 km s<sup>-1</sup> for mini-Earth,  16.8 km s<sup>-1</sup> for the Earth, 21.1 km s<sup>-1</sup> for Proxima Centauri b, and 36.1 km s<sup>-1</sup> for super-Earth.</p><p><strong>Results. </strong>We assume fully formed crusts, so melt volume immediately increases due to impacts. Super-Earth reaches a maximum of ~45% of the lithosphere in molten state, whereas mini-Earth reaches a maximum of only ~5%.  This is due to much higher impact velocities and cratering densities on the super-Earth compared to mini-Earth. We also show the geophysical habitable volumes within the upper 4 km of a planet’s crust as the bombardment progresses. Impacts sterilize the majority of the habitable volume on super-Earth; however, due to its large total volume, the total habitable volume is still higher than on other planets despite the more intense bombardment in terms of energy delivered per unit area.</p><p><strong>References:</strong> [1] Abramov, O., and S.J. Mojzsis (2009) Nature, 459, 419-422. [2] Abramov et al. (2013) Chemie der Erde, 73, 227-248. [3] Abramov, O., and S. J. Mojzsis (2016) Earth Planet Sci. Lett., 442, 108-120. [4] Canup, R. M. (2004) Icarus, 168, 433-456. [5] Abramov, O., and D. A. Kring (2004) J. Geophys. Res., 109(E10). [6] Tasker, E. J. et al. (2020). Astronom. J., 159(2), 41. [7] Marcy, G. W. et al. (2014). PNAS, 111(35), 12655-12660. [8] Kieffer S. W. and Simonds C. H. (1980) Rev. Geophys. Space Phys., 18, 143-181. [9] Pierazzo E., and H.J. Melosh (2000). Icarus, 145, 252-261. [10] Mojzsis, S. J. et al. (2019). Astrophys. J., 881(1), 44. [11] Bottke, W. F. et al. (2010) Science, 330, 1527-1530.</p>

1. What is geophysics?

2018 ◽  
pp. 1-5
Author(s):  
William Lowrie
Keyword(s):  
Magnetic Fields ◽  
Physical Properties ◽  
Complex Behaviour ◽  
Tectonic Plates ◽  
Natural Processes ◽  
Research Fields ◽  
The Earth ◽  
Deep Interior ◽  
Wide Range ◽  
Geophysical Investigations

Geophysics is a field of earth sciences that uses the methods of physics to investigate the complex physical properties of the Earth and the natural processes that have determined and continue to govern its evolution. ‘What is geophysics?’ explains how geophysical investigations cover a wide range of research fields—including planetary gravitational and magnetic fields and seismology—extending from surface changes that can be observed from Earth-orbiting satellites to complex behaviour in the Earth’s deep interior. The timescale of processes occurring in the Earth also has a very broad range, from earthquakes lasting a few seconds to the motions of tectonic plates that take place over tens of millions of years.

The deep interior of Venus, Mars, and the Earth: A brief review and the need for planetary surface-based measurements

2011 ◽  
Vol 59 (10) ◽  
pp. 1048-1061 ◽  
Author(s):  
Antoine Mocquet ◽  
Pascal Rosenblatt ◽  
Véronique Dehant ◽  
Olivier Verhoeven
Keyword(s):  
Planetary Surface ◽  
The Earth ◽  
Deep Interior

Materials Science of the Earth's Deep Interior

MRS Bulletin ◽  
1992 ◽  
Vol 17 (5) ◽  
pp. 30-37 ◽  
Author(s):  
A. Navrotsky ◽  
D.J. Weidner ◽  
R.C. Liebermann ◽  
C.T. Prewitt
Keyword(s):  
Materials Science ◽  
Basic Question ◽  
Material System ◽  
Sound Waves ◽  
Outer Planets ◽  
The Earth ◽  
Deep Interior ◽  
Direct Sampling ◽  
Deep Earth ◽  
Vertical Temperature Distribution

Man has walked on the moon, sent probes to or near the surfaces of Mars and Venus, and dispatched vehicles to fly near comets, asteroids, and the outer planets and their moons. In contrast, a journey to the center of the Earth remains as unattainable and fictional as in Jules Verne's day. We know the interior of our planet from several types of evidence: direct sampling of rock brought to the surface by geologic process from depths no greater than 200 km, remote sensing especially by seismology (the study of natural or anthropogenic sound waves passing through the Earth), inferences from the chemistry of meteorites and from other geochemical arguments, and laboratory and computational simulations of the conditions at depth. The laboratory study of Earth materials at high temperatures and pressures is the subject of this review. In a sense, the basic question of deep earth geophysics is a peculiar sort of inverse problem in materials science; rather than determining the properties of a given material, one seeks to find materials, under constraints of natural elemental abundances, which have properties consistent with seismological and other geophysical observations.What are the “hard facts” about planet Earth as a material system? Its radius and mass are well constrained, as are pressure and density as a function of depth (see Figure 1). Its vertical temperature distribution is less well known, but it is clear that the interior is hot, with temperatures in the mantle reaching perhaps 3000 K and in the core perhaps 6000–7000 K.

scholarly journals In situ Investigations from Spinels under high pressure and high Temperatures

2014 ◽  
Vol 70 (a1) ◽  
pp. C398-C398
Author(s):  
Michael Wehber ◽  
Frank Schilling ◽  
Christian Lathe ◽  
Hans Mueller
Keyword(s):  
High Pressure ◽  
Volume Change ◽  
X Ray Diffraction ◽  
Ambient Temperatures ◽  
The Earth ◽  
Deep Interior ◽  
State Apparatus ◽  
Temperature And Pressure ◽  
Murnaghan Equation

Spinels seem to be important constituents of the deep interior of the Earth while transition with spinel or pseudospinel structure strongly influence the dynamic of the mantle. On the other hand, spinels are widely used as artificial material. The spinels Magnetite, Franklinite, and Gahnite are investigated at the Hamburger Synchrotron Laboratory (HASYLAB) at Hamburg. The experiments were carried out using the high pressure multi anvil devices MAX80 (F2.1 Beamline) and MAX200x (W2 Beamline). The MAX80 is a single state apparatus located at a bending magnet, MAX200x is a double state system located at a wiggler. Energy-dispersive X-ray diffraction in combination with Rietveld refinement [1, 2] was used to determine the pressure and temperature induced volume change. Isothermal experiments were performed up to 15 GPa at ambient temperature. The temperature and pressure dependent volume change were derived from compression experiments using MAX80 apparatus up to 5 GPa at temperatures of 298, 500, 700, 900 and 1100 K. Bulk moduli at ambient temperatures using a Birch-Murnaghan equation of state result in KT=184(7) GPa with K'=4.5(2) for Magnetite, KT =178(6) with K'=4.6(4) for Franklinite, and KT =204(9) with K'=4.9(6) for Gahnite.

scholarly journals Less Known Results on the Solar System

2021 ◽  
Vol 13 (3) ◽  
pp. 45-55
Author(s):  
Horia DUMITRESCU ◽  
Vladimir CARDOS ◽  
Radu BOGATEANU
Keyword(s):  
Solar System ◽  
Actual World ◽  
Specific Activity ◽  
Big Bang ◽  
Space Time ◽  
Integral Approach ◽  
Earth Planet ◽  
The Earth ◽  
Computational Technology

For a two half millennium evolution of knowledge from the Democrit’s natural, rational atomized material conception to the Newtonian, Maxwellian, Einsteinian mathematized physics, the research in the most cases has followed a deductive route from observable facts/reality according to the Mach’s rigorous positivism principle. During the last century both experimental and computational technology progress has accumulated a solid factual datum support on the better knowledge of our actual world, so that the research is beginning on inductive route of the hidden/dark detailed processes as a whole. This revolutionary stage of physics, based on a holistic integral approach, is concerned with the relativity-gravity evolution in a quantifiable space-time universe created after the morphogenetic light explosion (or the 4D-BIG BANG). The paper presented herein contains some less known aspects on the work of solar system as a whole, along with the specific activity of the Earth-planet as a part integrated into the solar complex.

scholarly journals Creasy and Wu Receive 2019 Study of the Earth’s Deep Interior Section Award for Graduate Research

Eos ◽  
2020 ◽  
Vol 101 ◽  
Author(s):  
Keyword(s):  
San Francisco ◽  
Fall Meeting ◽  
Theoretical Approaches ◽  
The Earth ◽  
Graduate Research ◽  
Deep Interior ◽  
Planetary Bodies

Neala Marie Creasy and Wenbo Wu received the 2019 Study of the Earth’s Deep Interior Section Award for Graduate Research at AGU’s Fall Meeting 2019, held 9–13 December in San Francisco, Calif. The award is given annually for advances that contribute to “the understanding of the deep interior of the Earth or other planetary bodies using a broad range of observational, experimental, or theoretical approaches.”

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