Recommended classes in the Meteoritical Bulletin Database are assigned by the database editor. In most cases, this is based on the most recent classification that appears in either the Catalogue of Meteorites, MetBase, the US Antarctic Meteorite Newsletter, the Japanese Meteorite Newsletter, or the Meteoritical Bulletin. However, in a few cases it reflects differences of opinion about the proper way to classify the meteorite. The nomenclature used may also be modified by the editor to conform to an internally consistent classification scheme
The recommended classification CBb means:
"A carbonaceous chondrite of the CB group of subtype b (contains small chondrules)."
The highlighted words are defined as follows:
carbonaceous chondrite: A major class of chondrites that mostly have Mg/Si ratios near the solar value and oxygen isotope compositions that plot below the terrestrial fractionation line.
CB group: The Bencubbin-like (CB) association of carbonaceous chondrites. The CBa subgroup is distinguished by cm-sized chondrule-like objects, abundant metal (>half the volume), no fine-grained matrix, and almost no refractory inclusions. The CBb subgroup contains small chondrules (0.2 - 1 mm), abundant metal (~70 vol%), and some refractory inclusions. It is uncertain whether any or all CB meteorites are true chondrites, as they may have formed slightly later in solar system history.
Find all meteorites of type: CBb