Howardite

One type of meteoriteWork in progress. A solid natural object reaching a planet’s surface from interplanetary space. Solid portion of a meteoroid that survives its fall to Earth, or some other body. Meteorites are classified as stony meteorites, iron meteorites, and stony-iron meteorites. These groups are further divided according to their mineralogy and in the HED (Howardite, EucriteMost common type of achondrite meteorite and a member of the HED group. Eucrites are basalts composed primarily of pigeonite and anorthite (An60-98). Eucrites have been placed into three subgroups based on mineralogical and chemical differences. • Non-cumulate eucrites represent the upper crust that solidified on a magma ocean after, DiogeniteDiogenites belong to the evolved achondrite HED group that also includes howardites and eucrites. They are named after the Greek philosopher Diogenes of Apollonia, of the 5th century BCE, who was the first to suggest that meteorites come from outer space (a realization forgotten for over 2,000 years). They are) achondriteAn achondrite is a type of stony meteorite whose precursor was of chondritic origin and experienced metamorphic and igneous processes. They have a planetary or differentiated asteroidal origin where the chondritic parent body reached a sufficient size that through heating due to radioactive decay of Al (aluminum isotope) and gravitational group. Howardites are named after the English chemist Edward Howard (1774-1816), one of the pioneers of meteoriticsScience involved in the study of meteorites and related materials. Meteoritics are closely connected to cosmochemistry, mineralogy and geochemistry. A scientist that specializes in meteoritics is called a meteoriticist.. Consisting mostly of eucritic and diogenitic clasts and fragments, howardites are polymict breccias. However, they can also contain dark clasts of carbonaceous chondritic matter, other xenolithic inclusions, and impact melt clasts, indicating a regolithMixture of unconsolidated rocky fragments, soil, dust and other fine granular particles blanketing the surface of a body lacking an atmosphere. Regolith is the product of "gardening" by repeated meteorite impacts, and thermal processes (such as repeated heating and cooling cycles).   origin.

Howardites are defined by their ratio of eucritic and diogenitic material.  Howardites must contain 10% or more eucritic material and 10% or more diogenitic material – the mix can be 10% eucritic and 90% diogenitic material, or 90% eucritic and 10% diogenitic material.

Howardites likely represent regolith brecciaWork in Progress ... A rock that is a mechanical mixture of different minerals and/or rock fragments (clasts). A breccia may also be distinguished by the origin of its clasts: (monomict breccia: monogenetic or monolithologic, and polymict breccia: polygenetic or polylithologic). The proportions of these fragments within the unbrecciated material from the surface of the asteroid 4 VestaThird largest and fourth brightest asteroid; it was discovered in 1807 by Heinrich Olbers and named for the ancient Roman goddess of the hearth. 4 Vesta has a basaltic surface composition and an average density not much less than that of Mars. Evidently lava once flowed here indicating that the, consisting of eucritic and diogenitic debris excavated by the large impact that created the enormous craterBowl-like depression ("crater" means "cup" in Latin) on the surface of a planet, moon, or asteroid. Craters range in size from a few centimeters to over 1,000 km across, and are mostly caused by impact or by volcanic activity, though some are due to cryovolcanism. near 4 Vesta’s south pole. These fragments mixed with parts of the chondritic impactor, and the mixture was subsequently pulverized and metamorphosed by smaller impacts and the solar windSupersonic flow of high-speed charged particles continuously blowing off a star (mostly e- and p+). When originating from stars other than the Sun, it is sometimes called a "stellar" wind. The solar wind may be viewed as an extension of the corona into interplanetary space. The solar wind emanates radially to form a regolith. Similar regoliths cover the surface of the Moon and as is the case with howardites, lunar regolith breccias display high abundances of noble gasesElement occurring in the right-most column of the periodic table; also called "inert" gases. In these gases, the outer electron shell is completely filled, making them very unreactive. that have been implanted into the rock by the solar wind.