Howardites-eucrites-diogenites

In most respects, asteroid 4 Vesta is geochemically similar to the Moon. As judged from howardite-eucrite-diogenite (HED) meteorites (see Chapter 6), Vesta is an ancient, basalt-covered world (Keil, 2002). Its rocks are highly reduced, and its depletions in volatile and siderophile element abundances resemble those of lunar basalts. And like the Moon, Vesta is hypothesized to have had an early magma ocean. The exploration of Vesta is now in progress, and within a few years we may have enough data to discuss it in a similar way that we have considered the Moon. 

HED meteorites howardites, eucrites, diogenites Mesosiderites Pallasites... 

Goodrich C. A. and Righter K. (2000) Petrology of unique achondrite Queen Alexandra Range 93148 a piece of the pallasite (howardite-eucrite-diogenite ) parent body Meteorit. Planet. Sci. 35, 521—535. 

Pun A., Keil K., Taylor G. J., and Wider R. (1998) The Kapoeta howardite implications for the regolith evolution of the howardite-eucrite-diogenite parent body. Meteorit. Planet. Sci. 33, 835-851. 

Takeda H. (1997) Mineralogical records of early planetary processes on the howardite, eucrite, diogenite parent body with reference to Vesta. Meteorit. Planet. Sci. 32, 841-853. 

Ordinary Chondrites H Chondrites L Chondrites LL Chondrites Howardites Eucrites Diogenites Shergottites Ataxites ... 

RED Howardite-Eucrite-Diogenite meteorites (derived from Vesta )... 

Particularly conspicuous exposure age clusters in bold face, uncertain ones marked by a Howardites-Eucrites-Diogenites. b Ages of clusters of iron meteorites refer to C1 age-scale (see text). In the " K-scale, the double peak at 255 207 Ma in group IVA corresponds to a single peak at 375 Ma, whereas the IILAB peak at 460 Ma is shifted to 650 Ma (Voshage 1978, 1984). Oldest stated age of 2300 Myr (Deep Springs) refers to °K-scale. 

Figure 9. Exposure age distributions of HED meteorites (howardites, eucrites, diogenites) and aubrites or enstatite achondrites. The HED data are from the compilation by Welten et al. (1997), with only the (shielding corrected) Kr-Kr ages being displayed for the eucrites. Included are 4 new diogenite ages from Welten et al. (2001b). In addition, the -3 Myr age of the howardite Kapoeta has been added (Caffee and Nishiizumi 2001). For data sources of aubrites see text. Note the different abscissa scales between the lowermost panel and the others.

Fig. 18.25 Lunar basalt (open circles) collected by the Apollo astronauts and lunar meteorites (solid circles) collected in Antarctica occupy a well-defined area in coordinates of their Fe/ Mn, K/La, and (Fe/Sc) x 0.01 ratios. The achondrites of the HED (Howardite, Eucrite, Diogenite) groups (crosses) lie in a separate field. The SNC (solid triangles) meteorites (Shergottites, Nakhlites, Chassignites) originated from Mars. The sample numbered 1 is ALHA 81005 and 2 is Calkalong which was recovered in the Australian desert. The Fe/Sc ratio was reduced by a factor or 0.01 in order to prevent the data points from crowding into the Fe/Sc corner of the triangle (Data for ALHA 81005 from Korotev et al. 1983 and for the other samples from Hill et al. 1991)...

COOP Crystal Orbital Overlap Populations HED Howardite-Eucrite-Diogenite... 

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