Dense collection area
A dense collection area is a region where so many meteorites are found that they are named with the area's name plus a number rather than separate place names.
In ice fields and hot deserts, meteorites can accumulate over tens of thousands of years or more, and systematic searches recover hundreds from small areas. Traditional naming after the nearest locality breaks down, so the Nomenclature Committee designates dense collection areas (DCAs) with defined boundaries. Each meteorite receives the area name and a number, for example Dar al Gani 476, Dhofar 019 or Allan Hills 81005. In Antarctica the number generally encodes the collection season and a sequence; in hot deserts it is usually a running sequence.
DCAs exist in Antarctica, the Sahara (Libya, Algeria and elsewhere), Oman, the Atacama Desert in Chile and the Nullarbor Plain in Australia, among others. Northwest Africa (NWA) numbers are a separate system for meteorites, mostly bought through trade, whose precise find locations are unknown.
DCAs matter scientifically because accurate coordinates allow pairing, terrestrial-age studies and estimates of meteorite flux. Dar al Gani 476, a martian shergottite found in Libya in 1998, is a good example. Submissions from DCAs must include precise coordinates. Recovery and export are governed by national laws, which in some desert countries are strict, so permission must always be checked first.
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