Cadmium, indium, tin, tellurium, and sulfur in oceanic basalts: Implications for chalcophile element fractionation in the Earth

2000 ◽  
Vol 105 (B8) ◽  
pp. 18927-18948 ◽  
Author(s):  
Wen Yi ◽  
Alex N. Halliday ◽  
Jeff C. Alt ◽  
Der-Chuen Lee ◽  
Mark Rehkämper ◽  
...  
Keyword(s):  
The Earth ◽  
Chalcophile Element ◽  
Element Fractionation ◽  
Oceanic Basalts ◽  
Cadmium Indium

scholarly journals Ba, Rb and Cs in the Earth's Mantle

1983 ◽  
Vol 38 (2) ◽  
pp. 256-266 ◽  
Author(s):  
Albrecht W. Hofmann ◽  
William M. White
Keyword(s):  
Mobile Phase ◽  
Aqueous Fluid ◽  
Oceanic Islands ◽  
Primitive Mantle ◽  
Partial Melt ◽  
Ocean Ridges ◽  
The Earth ◽  
Isotopic Abundances ◽  
Oceanic Basalts ◽  
Relative Abundances

Abstract In 166 isotope dilution analyses of Ba, Rb, Cs on fresh basalts from mid-ocean ridges and oceanic islands, Ba/Rb and Cs/Rb ratios are nearly constant. From this, we conclude that Ba/Rb and Cs/Rb ratios are essentially constant in the present-day mantle in spite of large differences in the degree of source depletion or enrichment. As it appears improbable that these ratios could be both constant and non-primitive, we propose that they are representative of the primitive mantle and of the present-day crust-mantle system. We explain this uniformity of relative abundances as follows: the mantle is depleted by subtraction of a mobile phase such as a partial melt or an aqueous fluid. In either case, a significant amount of the mobile phase remains in the residue. Ba, Rb and Cs are among the most highly incompatible elements. Therefore the mobile phase cannot fractionate these elements relative to one another but retains the source ratios of Ba/Rb and Cs/Rb. Also, the amount of mobile phase remaining in the residue is enough to dominate the Ba, Rb and Cs concentrations in the residue. Consequently, neither the mobile phase nor the residue, nor any other portion of the mantle that may be enriched by addition of the mobile phase, will be changed in their relative abundances of Ba, Rb and Cs, even though the absolute abundances of these elements may change by orders of magnitude.The primitive Ba/Rb = 11.3 and Cs/Rb = 12.6 x 10-3 lead to the following estimates for the primitive mantle: Ba = 6.9 ppm (taken from Jagoutz et al. [1]). Rb = 0.61 ppm and Cs = 7.7 ppb.Assuming the earth has a chondritic Sr/Ba ratio of 3.08, we calculate a Rb/Sr ratio of 0.029 for the earth. This corresponds to a present-day 87Sr/ 86Sr of 0.7045. This value lies near the lower limit of the ratios estimated from the correlation of Nd and Sr isotopic abundances in oceanic basalts.The Cs/Rb ratios is about a factor of ten lower than the Cl-chondritic ratio and a factor of three lower than the lunar ratio. This low terrestrial Cs/Rb ratio should be matched by similar values in the continental crust. However, the large range of Cs/Rb ratios found in the crust prevent us from obtaining a meaningful mass balance.

The motion of a lunar orbiter

1966 ◽  
Vol 25 ◽  
pp. 373
Author(s):  
Y. Kozai
Keyword(s):  
Degrees Of Freedom ◽  
Dimensional Space ◽  
Artificial Satellite ◽  
Equations Of Motion ◽  
Triaxial Ellipsoid ◽  
The Moon ◽  
Secular Motion ◽  
The Earth ◽  
Close Satellite ◽  
The Mean

The motion of an artificial satellite around the Moon is much more complicated than that around the Earth, since the shape of the Moon is a triaxial ellipsoid and the effect of the Earth on the motion is very important even for a very close satellite.The differential equations of motion of the satellite are written in canonical form of three degrees of freedom with time depending Hamiltonian. By eliminating short-periodic terms depending on the mean longitude of the satellite and by assuming that the Earth is moving on the lunar equator, however, the equations are reduced to those of two degrees of freedom with an energy integral.Since the mean motion of the Earth around the Moon is more rapid than the secular motion of the argument of pericentre of the satellite by a factor of one order, the terms depending on the longitude of the Earth can be eliminated, and the degree of freedom is reduced to one.Then the motion can be discussed by drawing equi-energy curves in two-dimensional space. According to these figures satellites with high inclination have large possibilities of falling down to the lunar surface even if the initial eccentricities are very small.The principal properties of the motion are not changed even if plausible values ofJ3andJ4of the Moon are included.This paper has been published in Publ. astr. Soc.Japan15, 301, 1963.

Formation of Lunar Craters and Bright Rays as a Result of Meteorite Impacts

1962 ◽  
Vol 14 ◽  
pp. 415-418
Author(s):  
K. P. Stanyukovich ◽  
V. A. Bronshten
Keyword(s):  
Explosive Charge ◽  
The Moon ◽  
Meteorite Impacts ◽  
The Earth ◽  
Lunar Craters ◽  
The Impact

The phenomena accompanying the impact of large meteorites on the surface of the Moon or of the Earth can be examined on the basis of the theory of explosive phenomena if we assume that, instead of an exploding meteorite moving inside the rock, we have an explosive charge (equivalent in energy), situated at a certain distance under the surface.

The Origin of the Moon

1962 ◽  
Vol 14 ◽  
pp. 149-155 ◽  
Author(s):  
E. L. Ruskol
Keyword(s):  
Chemical Composition ◽  
Solar System ◽  
The Moon ◽  
The Earth ◽  
The Difference ◽  
Origin Of The Moon

The difference between average densities of the Moon and Earth was interpreted in the preceding report by Professor H. Urey as indicating a difference in their chemical composition. Therefore, Urey assumes the Moon's formation to have taken place far away from the Earth, under conditions differing substantially from the conditions of Earth's formation. In such a case, the Earth should have captured the Moon. As is admitted by Professor Urey himself, such a capture is a very improbable event. In addition, an assumption that the “lunar” dimensions were representative of protoplanetary bodies in the entire solar system encounters great difficulties.

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.

Probable Structure and Nature of the Formations on the Reverse Side of the Moon According to Photometric Measurements of Lunar Photographs

1962 ◽  
Vol 14 ◽  
pp. 39-44
Author(s):  
A. V. Markov
Keyword(s):  
The Moon ◽  
Probable Structure ◽  
The Earth ◽  
Interplanetary Station ◽  
Photometric Measurements ◽  
Automatic Interplanetary Station

Notwithstanding the fact that a number of defects and distortions, introduced in transmission of the images of the latter to the Earth, mar the negatives of the reverse side of the Moon, indirectly obtained on 7 October 1959 by the automatic interplanetary station (AIS), it was possible to use the photometric measurements of the secondary (terrestrial) positives of the reverse side of the Moon in the experiment of the first comparison of the characteristics of the surfaces of the visible and invisible hemispheres of the Moon.

Seti Space Missions

1997 ◽  
Vol 161 ◽  
pp. 761-776 ◽  
Author(s):  
Claudio Maccone
Keyword(s):  
Electromagnetic Waves ◽  
Space Missions ◽  
Gravitational Lens ◽  
The Sun ◽  
Space Antenna ◽  
Focal Distance ◽  
Large Space ◽  
The Earth ◽  
Space Antennas ◽  
New Space

AbstractSETI from space is currently envisaged in three ways: i) by large space antennas orbiting the Earth that could be used for both VLBI and SETI (VSOP and RadioAstron missions), ii) by a radiotelescope inside the Saha far side Moon crater and an Earth-link antenna on the Mare Smythii near side plain. Such SETIMOON mission would require no astronaut work since a Tether, deployed in Moon orbit until the two antennas landed softly, would also be the cable connecting them. Alternatively, a data relay satellite orbiting the Earth-Moon Lagrangian pointL2would avoid the Earthlink antenna, iii) by a large space antenna put at the foci of the Sun gravitational lens: 1) for electromagnetic waves, the minimal focal distance is 550 Astronomical Units (AU) or 14 times beyond Pluto. One could use the huge radio magnifications of sources aligned to the Sun and spacecraft; 2) for gravitational waves and neutrinos, the focus lies between 22.45 and 29.59 AU (Uranus and Neptune orbits), with a flight time of less than 30 years. Two new space missions, of SETI interest if ET’s use neutrinos for communications, are proposed.

Statistical results on discovered near-Earth asteroids

1999 ◽  
Vol 173 ◽  
pp. 81-86
Author(s):  
S. Berinde
Keyword(s):  
Dynamical Evolution ◽  
Minor Planet ◽  
Orbital Elements ◽  
The Earth ◽  
Near Earth Asteroids ◽  
Statistical Results

AbstractThe first part of this paper gives a recent overview (until July 1st, 1998) of the Near-Earth Asteroids (NEAs) database stored at Minor Planet Center. Some statistical interpretations point out strong observational biases in the population of discovered NEAs, due to the preferential discoveries, depending on the objects’ distances and sizes. It is known that many newly discovered NEAs have no accurately determinated orbits because of the lack of observations. Consequently, it is hard to speak about future encounters and collisions with the Earth in terms of mutual distances between bodies. Because the dynamical evolution of asteroids’ orbits is less sensitive to the improvement of their orbital elements, we introduced a new subclass of NEAs named Earth-encounter asteroids in order to describe more reliably the potentially dangerous bodies as impactors with the Earth. So, we pay attention at those asteroids having an encounter between their orbits and that of the Earth within 100 years, trying to classify these encounters.

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