Spatial distribution and classification of Algerian meteorites: Qualitative and quantitative inventory

Abstract

This paper deals with statistical classification of the Algerian meteorites, based on the Metbull database, as well as their distribution in space and time. The Algerian-recognized meteorites number 1,230, six of which are observed falls. All types and classes are represented, ranging from ordinary chondrites to rare achondrites.Among the most scientifically significant meteorite types, are the carbonaceous chondrites, in particular: (a) Acfer 059 that yields an age of 4,564.7 ± 0.6 Ma; (b) Acfer 086 which is a ‘CV3’ type that contains the molecule hemolithin which is similar to terrestrial proteins; (c) Acfer 094 (found in 1990), which is a C2-ungrouped type that is considered as the oldest known meteorite containing pre-solar grains; and (d) NWA 2,364 which is also a ‘CV3’ type meteorite that yields an age of 4,568.2 Ma, and contains predominantly of CAIs (calcium-aluminum inclusions).Other undifferentiated achondrites of a primitive type and the asteroidal HED meteorites have also been identified. Among the iron meteorites, two specimens (Zeghamra and Tamentit) display a mass of several hundreds of kilograms. Erg Chech “EC002” is considered as the oldest of the solar system with an age of 5,668 Ma. The SNC-type Martian meteorites comprise ten recognized specimens, whilst the lunar meteorites, such as the Issaouane-n-Irrarrene 001, are the latest to be found. Using all recognized Algerian meteorites, a distribution map is established based on the Metbull database. Chronological evolution of both the number of finds in the Acfer stranding field, and the number of finds in Algeria since 1864, is discussed. In addition to meteorites, Algeria hosts four hypervelocity impact structures, namely: Amguid, Talemzane-Maadna, Ouarkziz, and Tin Bider.