Tamdakht H5 Meteorite - 27.7g Fragment
Tamdakht is one of our favorite meteorites. It's fresh, attractive, stable, and affordable. This 27.7 gram fragment displays the characteristic dull black fusion crust that Tamdakht is known for over about 65% of the stone, with the remaining areas featuring the rich, grey H5 inner matrix.
History: On December 20, 2008, witnesses from a number of locations in Morocco (Agadir, Marrakesh, Ouarzazate) observed a meteor with a W to E trajectory. According to the local newspaper, Al Massae (of December 27th), people from the high Atlas Mountains (between Marrakesh and Ouazazate) heard a sound and felt an aftershock. Due to the high relief in this mountain region, covered with snow at this time of the year, searching for the meteorite was a difficult task. The first reports on finding pieces of a meteorite came a couple of weeks later. The largest impact pit is located near Oued Aachir (1.10 m diameter and 70 cm depth, 31°09.8′N, 7°00.9′W), with a stone exceeding 30 kg and many small fragments. A second one is smaller, (about 20 cm diameter and 10 cm depth; 31°09.9′N 07°02.3′W) located 2 km W from the first one; the main mass from the second impact was probably about 500 g. A strewn field of at least 25 km long and 2 km wide has been outlined.
Physical characteristics: Total weight is presently estimated to be 100 kg. Pieces recovered as of February 15, 2009, are 30 kg, 1.5 kg, 3.8 kg, 3.69 kg, 2.4 kg, 1.5 kg, 1 kg, 800 g, and 399 g. One major fragment of 1.7 kg and many small pieces from the same stone (ranging 500 to below 1 g) were also recovered. The largest fragment shows a nearly complete dull gray fusion crust, other pieces are 90% crusted to free of crust, often broken along preexisting fractures. Thick fusion crust, locally more than 1 mm.
Petrography (Albert Jambon, Omar Boudouma, D. Badia UPVI and M. Denise, MNHNP): Abundant chondrules with visible but not well-delimited outlines. Chondrule size is 0.1 to 1.5 mm. Dominant olivine and orthopyroxene. Abundant chromite, rare clinopyroxene and ilmenite. Numerous pockets with chromite, plagioclase and phosphate (merrilite and Cl-apatite). Kamacite, with deformed Neumann bands, and taenite, twinned troilite. Copper. Mode: metal+troilite 10%.
Mineral compositions and geochemistry: log χ = 5.3. Olivine Fa18 ± 0.5 Opx = En83 Fs16 Wo2 Minor calcic pyroxene. Plagioclase is Ab83–86 An5–15 Or7–2. Ca-phosphate (merrillite and Cl-apatite). Chromite: Cr# (100× molar Cr/[Cr + Al]) = 82. Metal: kamacite with 5% Ni and taenite with 36–47% Ni. Oxygen isotopes (C. Suavet, J. Gattacecca CEREGE): δ17O = 3.26‰, δ18O = 5.01‰, and Δ17O = 0.65‰. Magnetic susceptibility is log χ = 5.3 × 10–9 m3/kg.