Dhofar 1436                        18°25.4'N, 54°25.4'E

Dhofar, Oman

Find: 8 December 2004

Achondrite (lunar feldspathic impact-melt breccia)

History: This meteorite was discovered by an anonymous finder on a limestone plateau in the Dhofar region in Oman, far from other known lunar meteorites.

Physical characteristics: A single brownish green stone of 24.2 g total weight. Fusion crust is absent.

Petrography: (Lorenz C. and Nazarov M., Vernad) The meteorite is an impact melt breccia, consisting of lithic and mineral clasts embedded in a partly devitrified glassy matrix with abundant bubbles. The lithic clasts are mainly impact melt breccias and rocks of anorthositic, gabbro-anorthositic, and gabbro-noritic compositions. Granular breccia clasts are also present. Lithic fragments range from 0.01 to 7 mm in size. Major minerals are pyroxene and feldspar, with minor olivine. Accessories are silica, chromite, ilmenite, Ca phosphate, troilite and FeNi metal.

Mineral composition and Geochemistry: (Lorenz C., Kononkova N., Vernad, EMP): Feldspar (An_92.5-98.7Ab_1.1-7.2); orthopyroxene (En_68.2-84.1Wo_0.2-5.0; Fe/Mn 62); clinopyroxene (En_13.4-63.7Wo_12.8-40.5; Fe/Mn 63); olivine (Fo_42.6-72.7; Fe/Mn 96); spinel is Al-Ti chromite. Average glassy matrix composition: SiO₂ = 45.1, TiO₂ = 0.26, Al₂O₃ = 30.8, FeO = 4.49, MgO = 3.94, CaO = 16.7, Na₂O = 0.48, K₂O = 0.04 [all wt%]. Oxygen isotopes: (I. A. Franchi, OU) δ¹⁷O = 3.286; δ¹⁸O = 6.244 (both ‰).

Classification: Achondrite (lunar feldspathic impact-melt breccia); minor weathering. Specimens: A type specimen of 5.2 g and one thin section are on deposit at Vernad. An anonymous collector holds the main mass.

Submitted by: Marina Ivanova, Vernad.