Gold basin meteorite strewn field, Mojave Desert, northwestern Arizona: Relic of a small late pleistocene impact event

Over 4450 meteorite specimens with a total mass of 168 760 g have been foun d in the Gold Basin (L4) strewn field over an area of 225 km(2). The meteor ite is a breccia, composed only of fragments of L-chondrite materials. The parent meteoroid had a kinetic energy equivalent to similar to5 to 50 ktons when it hit the top of the atmosphere. Cosmogenic nuclide studies indicate the meteorite has a terrestrial age of 15 000 +/- 600 years, corresponding to the Late Pinedale portion of the Wisconsin Glaciation. Conditions in th e Gold Basin, which is now part of the Mojave Desert, were wetter and coole r at the time of the fall. Mossbauer analyses indicate the sample is 30 to 35% oxidized. This is less than that in meteorites with similar ages found in eastern New Mexico, but comparable to that found in meteorites from the Sahara and the Nullarbor Region. Oxidation is likely to have occurred soon after the fall, when exposure to precipitation was at its maximum. Four oth er new meteorites were also found in the Gold Basin strewn field.