Northwest Africa 7447 (NWA 7447)

(Northwest Africa)

Purchased: 2007

Classification: Enstatite chondrite (EL5)

History: Purchased by Romano Serra at the Bologna Mineral Show at the Erfoud market, Morocco.

Physical characteristics: Single fragment without fusion crust.

Petrography: (V. Moggi Cecchi, G. Pratesi, S. Caporali, MSP); The thin section displays a few chondrules set in a fine-grained matrix, dominated by pyroxene, with minor plagioclase. Chondrules are still distinguishable and range from 0.5 to 0.9 mm in diameter and are mainly RP type, with minor PP. Opaque phases are mainly kamacite and troilite, almost completely weathered to iron oxides. Accessory phases are daubreelite and rare alabandite spots. The presence of alabandite, An content of plagioclase, Mn content of daubreelite and Si content of kamacite point to a classification as EL chondrite. The presence of distinct chondrules suggests a petrologic type 5.

Geochemistry: Orthopyroxene Fs_0.1Wo_1.4, plagioclase (An_15.5Or_3.9); Si in kamacite = 1.8 wt.%, Mn in Daubreelite = 2.6 wt.%.

Classification: Enstatite chondrite (EL5); S2; W1

Specimens: A total of 20.3 g specimen and one thin section is on deposit at MSP (MSP 5195). The main mass is in deposit at OAM.