Fell August 21, 1991
18° 42′ N., 4° 48′ E. On an August afternoon, a seven-year-old Tuareg boy witnessed the fallMeteorite seen to fall. Such meteorites are usually collected soon after falling and are not affected by terrestrial weathering (Weathering = 0). Beginning in 2014 (date needs confirmation), the NomComm adopted the use of the terms "probable fall" and "confirmed fall" to provide better insight into the meteorite's history. If Click on Term to Read More of a 110 kg stone in Tahoua, Republic of Niger. This is a uniquely unshocked (S1) meteoriteWork in progress. A solid natural object reaching a planet’s surface from interplanetary space. Solid portion of a meteoroid that survives its fall to Earth, or some other body. Meteorites are classified as stony meteorites, iron meteorites, and stony-iron meteorites. These groups are further divided according to their mineralogy and Click on Term to Read More with high porosityThe volume percentage of a rock that consists of void space. Vesicular porosity is a type of porosity resulting from the presence of vesicles, or gas bubbles, in igneous rock such as the pumice presented here. Vesicular porosity is very rare in meteorites and is often associated with slag, one Click on Term to Read More and large vugs containing crystals of silicates, troiliteBrass colored non-magnetic Fe sulfide, FeS, found in a variety of meteorites., and FeNi-metal. Mount Tazerzait shares many similarities with the meteorite Baszkówka; some of these are the low shock stageA petrographic assessment, using features observed in minerals grains, of the degree to which a meteorite has undergone shock metamorphism. The highest stage observed in 25% of the indicator grains is used to determine the stage. Also called "shock level". Click on Term to Read More of S1, unusually high porosity, crystal growth inside vugs, very long cosmic-ray exposure ageTime interval that a meteoroid was an independent body in space. In other words, the time between when a meteoroid was broken off its parent body and its arrival on Earth as a meteorite - also known simply as the "exposure age." It can be estimated from the observed effects Click on Term to Read More (~61 and ~76 m.y., respectively), noble gasElement occurring in the right-most column of the periodic table; also called "inert" gases. In these gases, the outer electron shell is completely filled, making them very unreactive. Click on Term to Read More abundance, chemical composition, and date of fall. These similarities suggest that both meteorites might be members of a meteor streamRelatively narrow band of meteoroids stretched out along the orbital path of a comet. It consists of dust released from the nucleus of a comet during its perihelion passage. The dust grains escape the weak gravity of the nucleus and travel on their own independent, heliocentric orbits. Although these orbits ejected from the same source region on their parent bodyThe body from which a meteorite or meteoroid was derived prior to its ejection. Some parent bodies were destroyed early in the formation of our Solar System, while others like the asteroid 4-Vesta and Mars are still observable today. Click on Term to Read More. Additionally, the L5 meteorite named Tjerebon, from Java, Indonesia, may be another member of this meteorHow long Sonic booms Of the several 10s of tons of cosmic material entering Earth's atmosphere each day, only about one ton reaches the surface. An object's chance of survival depends on its initial mass, speed and angle of entry, and friability (tendency to break up). Micrometeoroids radiate heat so Click on Term to Read More stream.
A proposed model for the development of high porosities in meteorites was presented in an article by Przylibski et al.
, vol. 38, #6 (2003). In their paper, ‘PetrologyScience dealing with the origin, history, occurrence, chemical composition, structure and classification of rocks. Click on Term to Read More
of the Baszkówka L5 chondriteChondrites are the most common meteorites accounting for ~84% of falls. Chondrites are comprised mostly of Fe- and Mg-bearing silicate minerals (found in both chondrules and fine grained matrix), reduced Fe/Ni metal (found in various states like large blebs, small grains and/or even chondrule rims), and various refractory inclusions (such Click on Term to Read More
: A record of surface-forming processes on the parent body’, the authors describe how an early collision of two thinly-crusted, molten planetesimalsHypothetical solid celestial body that accumulated during the last stages of accretion. These bodies, from ~1-100 km in size, formed in the early solar system by accretion of dust (rock) and ice (if present) in the central plane of the solar nebula. Most planetesimals accreted to planets, but many – Click on Term to Read More
occurred within the first two million years of Solar SystemThe Sun and set of objects orbiting around it including planets and their moons and rings, asteroids, comets, and meteoroids.
history. This collision produced a hot cloud of low-density chondritic material, which thereafter, slowly accreted onto the surface of the larger body. This homogeneous material was then loosely welded together by hot, plastic metalElement that readily forms cations and has metallic bonds; sometimes said to be similar to a cation in a cloud of electrons. The metals are one of the three groups of elements as distinguished by their ionization and bonding properties, along with the metalloids and nonmetals. A diagonal line drawn Click on Term to Read More
and sulfides. Material that remained near the surface of the planetesimal developed ubiquitous impact-generated microcracks resulting in the highest total porosities, such as is found in the ordinary chondritesChondrites are the most common meteorites accounting for ~84% of falls. Chondrites are comprised mostly of Fe- and Mg-bearing silicate minerals (found in both chondrules and fine grained matrix), reduced Fe/Ni metal (found in various states like large blebs, small grains and/or even chondrule rims), and various refractory inclusions (such Click on Term to Read More
Baszkówka, Miller (20%), NWA 2380 (18.7%), and Sahara 98034
(16.1 [±2.0] %), while those meteorites with somewhat less porosity such as Mount Tazerzait (12.6%) were more deeply buried and experienced more complete compaction ((Sasso et al.
, 2009). These meteorites did not experience further recrystallization, and therefore, their petrography reflects the conditions that existed during the earliest period of solar systemDefinable part of the universe that can be open, closed, or isolated. An open system exchanges both matter and energy with its surroundings. A closed system can only exchange energy with its surroundings; it has walls through which heat can pass. An isolated system cannot exchange energy or matter with
These meteorites likely originated on a separate parent body than that of other L chondrites, one on which a low shock history has preserved the primary porosity. The growth of euhedral crystals inside the pores might have been created during equilibration involving solutions originally present on the Mount Tazerzait–Baszkówka parent body. The above specimen is a 37.8 g cut fragment with a polished face showing the high porosity of this meteorite.
For additional information on the Mount Tazerzait meteorite, read the article by Dr. Svend Buhl on the Meteorite Recon website—‘Mount Tazerzait Meteorite: Unlocking an eventful past’