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 EL4/5 means:
"An enstatite chondrite of the EL group that is either petrologic type 4 or type 5."
The highlighted words are defined as follows:
enstatite chondrite: A major class of chondrites that mostly have sub-solar Mg/Si and refractory/Si ratios, oxygen isotope compositions that plot near the terrestrial fractionation line, and highly reduced mineral assemblages (containing little FeO, Si-bearing metal, and sulfides of elements normally considered lithophile).
EL group: The low-iron (EL) chemical group of enstatite chondrites, distinguished by moderately large chondrules (0.6 mm), abundant metal (~10 vol%) that is Si-bearing (~1 wt%), and an extremely reduced mineral assemblage containing ferroan alabandite ((Fe,Mn)S).
type 4: Designates chondrites that are characterized by abundant chondrules, and have been metamorphosed under conditions sufficient to homogenize olivine compositions and recrystallize fine-grained matrix. Some of the low-Ca pyroxene grains may be monoclinic and exhibit polysynthetic twinning. Primary igneous chondrule glass is absent.
type 5: Designates chondrites that have been metamorphosed under conditions sufficient to homogenize olivine and pyroxene, convert all low-Ca pyroxene to orthopyroxene, cause the growth of various secondary minerals, and blur chondrule outlines.
Find all meteorites of type: EL4/5