The Atacama Desert: A preferential arid region for the recovery of meteorites-Find location features and strewnfield distribution patterns

摘要

Some terrestrial areas have favorable climatic and geomorphologic features that permit the preservation and accumulation of meteorites. The Atacama Desert is among the most important ones. Sixty-two, non-paired, meteorites have been collected in different places of Atacama since the late 19th century to date. Practically all types, classes and groups of meteorites have been recovered. In this work a review of the Atacama meteorites is carried out, listing all past recoveries, determining the principal strewnfield distribution patterns and providing a general overview of the features of the find locations. Principal find locations are concentrated in the Atacama Central Depression. Most of them coincide with ancient mining industries (metallic or non-metallic) or are located near towns, rail stations, tracks or human settlements. Whatever the meteorite find location was, all meteorite samples were collected on the desert surface and normally: (1) showed more than a quarter of their body exposed; (2) underwent some sign of terrestrial weathering; (3) stone meteorites have a brownish desert-varnish on hand specimen; (4) are non-oriented pieces and (5) are commonly members of a greater mass distributed in a certain place. The distribution of find locations in Atacama Desert is not as simple as it would seem on a first approach, as Atacama salt phases (environmental conditions and mineralogical alterations) have a crucial importance on meteorites weathering.