The composition of the primitive mantle derived here shows that Earth was assembled from material that shows many of the same chemical fractionation processes as chondritic meteorites. These processes occurred at the initial stage of the solar system formation, under conditions thought to be present in the solar nebula. But the stable isotope record excludes chondritic meteorites as the ‘building blocks’ of Earth. Meteorites formed in local environments separated from that part of the inner solar system where much of the material forming the terrestrial planets was sourced.

https://booksite.elsevier.com/brochures/treatiseongeochemistry/contents/sample2.pdf

Cosmochemical Estimates of Mantle Composition

A Bose–Einstein condensate represents the most ‘classical’ form of a matter wave, just as an optical laser emits the most classical form of an electromagnetic wave. Nevertheless, the matter wave field has a quantized structure owing to the granularity of the discrete underlying atoms. Although such a field is usually assumed to be intrinsically stable (apart from incoherent loss processes), this is no longer true when the condensate is in a coherent superposition of different atom number states1,2,3,4,5,6. For example, in a Bose–Einstein condensate confined by a three-dimensional optical lattice, each potential well can be prepared in a coherent superposition of different atom number states, with constant relative phases between neighbouring lattice sites. It is then natural to ask how the individual matter wave fields and their relative phases evolve. Here we use such a set-up to investigate these questions experimentally, observing that the matter wave field of the Bose–Einstein condensate undergoes a periodic series of collapses and revivals; this behaviour is directly demonstrated in the dynamical evolution of the multiple matter wave interference pattern. We attribute the oscillations to the quantized structure of the matter wave field and the collisions between individual atoms.

Collapse and revival of the matter wave field of a Bose–Einstein condensate

Oxygen isotope studies of achondrites

Zolensky ME, and McSween, HY Jr (1988) Aqueous alteration. In Meteorites and the Early Solar System (JF KCITIdge, MS Matthews cds) Univ. of Ari zona, Tucson, 114143 Zoicnsky ME, Score R, Schutt JW, Clayton RN, Mayeda TK (1989a) Lea County 001, an H5 chondrile, and Lea County 002, an ungrouped type 3 chondrite. Meteoritics 24:227-232 Zolensky ME, Barrett R, Prinz M (l989b) Petrography and mineralogy of Yamalo-86720 and Belgica7904. 14th Syrup Ant Meteorites 24-26 Zolensky ME, Barrett R, Prinz M (1989c) Petrography, mineralogy and matrix composition of Yamato82162, a new el2 chondrite (abstr). Lunar Planet Sci XXVL1253-1254 Zolensky ME, Prinz M, Lipschutz ME (199 1) Mineralogy and thermal history of Y-82162, Y-86720, B7904, Abstr Symp Antarct Met 16:195-196 Zolensky ME, Hewins RH , ~ittlefehldt DW, Lindstrom MM, Xiao X, Lipschutz ME (1992) Mineralogy, petrology and geochemistry of carbonaceous chondritie clasts in the LEW 85300 polymiet eucrite. Meteoritics 27:596-604 Zolcnsky ME, Barrett T, Browning L (1993) Mineralogy and composition of matrix and chondrule rims in carbonaceous chondrites. Geochim Cosmochim Acta 57:3123-3148 Zolcnsky ME, Weisb~g MK, Buchanan PC, Mittlcfehldt DW (l996a) Mineralogy of carbonaceous chondrite clasts in HED achondrites and the Moon. Met Planet Sci 31 :518-537 Zol ensky ME, Ivanov AV, Yang V, Mittlefehldt DW, Ohsumi K (l996b) The Kaidun meteorite: Mineralogy of an unusual CM 1 lithology. Meteoritics 31 :484-493 Chapter 4

Non-chondritic meteorites from asteroidal bodies

The well investigated size-frequency distributions (SFD) for lunar craters is used to estimate the SFD for projectiles which formed craters on terrestrial planets and on asteroids. The result shows the relative stability of these distributions during the past 4 Gyr. The derived projectile size-frequency distribution is found to be very close to the size-frequency distribution of Main-Belt asteroids as compared with the recent Spacewatch asteroid data and astronomical observations (Palomar-Leiden survey, IRAS data) as well as data from close-up imagery by space missions. It means that asteroids (or, more generally, collisionally evolved bodies) are the main component of the impactor family. Lunar crater chronology models of the authors published elsewhere are reviewed and refined by making use of refinements in the interpretation of radiometric ages and the improved lunar SFD. In this way, a unified cratering chronology model is established which can be used as a safe basis for modeling the impact chronology of other terrestrial planets, especially Mars.

Cratering Records in the Inner Solar System in Relation to the Lunar Reference System

An attempt is made to construct a simple model of the evolution of the asteroid belt from the data available about the individual asteroids. Data on the meaning of taxonomic types, the stratigraphy of the asteroid belt, the compositional meaning of Tholen space, collisional and dynamical history, and asteroid shapes are reviewed. Two main paradoxes concerning asteroids, called the ordinary chondrite mystery and the olivine problems, are briefly described. Finally, the tentative model is presented, showing how it takes into account condensation locations, heating, collisional evolution, and delivery of asteroids to earth.

Asteroids - The big picture

The first images of the asteroid 243 Ida from Galileo show an irregular object measuring 56-kilometers by 24 kilometers by 21 kilometers. Its surface is rich in geologic features, including systems of grooves, blocks, chutes, albedo features, crater chains, and a full range of crater morphologies. The largest blocks may be distributed nonuniformly across the surface; lineaments and dark-floored craters also have preferential locations. Ida is interpreted to have a substantial regolith. The high crater density and size-frequency distribution (–3 differential power-law index) indicate a surface in equilibrium with saturated cratering. A minimum model crater age for Ida—and therefore for the Koronis family to which Ida belongs—is estimated at 1 billion years, older than expected.

http://www.planetary.brown.edu/pdfs/1598.pdf

First Images of Asteroid 243 Ida

Asteroid collisional evolution studies are aimed at understanding how collisions have shaped observed features of the asteroid population in order to further our understanding of the formation and evolution of our solar system. We review progress in developing more realistic collisional scaling laws, the effects of relaxing over-simplifying assumptions used in earlier collisional evolution studies, and the implications of including observables, such as collisionally produced families, on constraining the collisional history of main-belt asteroids. Also, collisional studies are extended to include Jupiter Trojans and the Hilda population. Results from collisional evolution models strongly suggest that the mass of main-belt asteroids was only modestly larger, by up to a factor of 5 or so, at the time that the present collisionally erosive environment was established, presumably early in solar system history. Major problems remain in identifying the appropriate scaling algorithm for determining the threshold for catastrophic disruption as well as understanding the resulting size and velocity distribution of fragments. Dynamical effects need to be combined with collisional simulations in order to understand the structure of the small asteroid size distribution.

/pdf/collisional-evolution-of-small-body-populations-2mt2ph9esw.pdf

D. R. Davis

Papers

Asteroids - The big picture

First Images of Asteroid 243 Ida

Collisional evolution of small body populations

Collisional Evolution of Trojan Asteroids

Collisional evolution of asteroids