CH Chondrite

Rare carbonaceous chondrite class that is chemically very close to the CRs and CBs as evidenced by the CH/CBb meteorite Isheyevo. The “H” stands for “high metal” since the CH chondrites contain up to 15 vol. % Fe-Ni metal. The first CH chondrite was found in the Antarctic Allan Hills (ALH 85085) and can be regarded as the type specimen. They also have many small fragmented chondrules (~0.05 mm diameter; 5-10 vol. %) and less abundant CAIs (<1 vol. %). All members recovered so far belong to petrologic type 3. As with the CRs, the CHs contain some phyllosilicates and other traces of aqueous alteration. Some CH chondrites are known to contain rare mineral phases, and in one member, NWA 470, the mineral Ca-monoaluminate, CaAl2O4, has been found for the first time in nature. However, unlike all other carbonaceous chondrites, the matrix of CHs is dominated by pyroxene (~70 vol. %).... Expand

 

Some or all content above used with permission from J. H. Wittke.