Description
Retuerta del Bullaque 39°27’32″N, 4°22’39″W
Castilla-La Mancha, Spain
Found: 1980
Classification: Iron meteorite (IAB-MG)
History: The specimen was discovered by Faustino Asensio López in 1980 at an agricultural farmland where he often worked with his father. The iron was found about 1.5 km from Retuerta del Bullaque, Ciudad Real, Spain, close to the northern boundary of Cabañeros National Park. The finder recognized the unusual density of the rock and found no crater. For more than fifteen years the meteorite remained on the family home patio, and later was used as a weight for the ham-curing process. Mr. Asensio López suspected an extraterrestrial origin of the specimen when he watched a TV news report on the sighting of a meteor over Spain on February 28, 2011, so later that year he contacted Juan C. Gutiérrez-Marco (CSIC-IGE) and Rafael P. Lozano (IGME) to check the authenticity of the specimen.
Physical characteristics: One mass of about 100 kg and average dimensions of 45 × 31 × 20 cm. Irregular but somewhat rectangular shape, with many concave surface features. The original surface shows moderate terrestrial weathering.
Petrography: (R.P. Lozano, IGME; J.C. Gutiérrez-Marco, CSIC-IGE). Two etched sections (77.7 and 41.1 cm2) show a Widmanstätten pattern (bandwidth: 2.0 ± 0.3 mm), with abundant cohenite lamellae (9.5% of total area), irregularly bordered by accessory schreibersite and enveloped in swathing kamacite. Taenite is present in 0.02-0.3 mm thick lamellae along kamacite and between kamacite bands (0.3-4 mm max. size pearlitic plessite). There are abundant kamacite grains showing polygonal sectors, with conspicuous Neumann lines and without cohenite. The larger sections display eight irregularly shaped graphite-FeS nodules (max. size, 5-12 mm), located in the central areas of the kamacite polygonal sectors. Each of the nodules has a 1-3 mm-thick rim of schreibersite + cohenite.
Geochemistry: (Jesús Reyes, IGME). Bulk composition: Ni = 7.527, Co = 0.475 (ICP-AES data, in wt%). Ga = 68.9, Ge = 365, As = 13.7, W = 0.95, Ir = 1.95, Au = 1.695 (ICP-MS data, in ppm).
Classification: (R.P. Lozano, IGME). Iron meteorite, coarse octahedrite, IAB complex (MG), cohenite rich, moderate weathering.
Specimens: A 1278 g type specimen, two fragments of 388 and 50 g, and three polished sections at IGME. The finder, F. Asensio López, and his brothers hold the main mass of about 98 kg.
