Notes on Meteorites in North Africa Countries

Prof. Mohamed Th.S. Heikal* Mohamed M. Elshora**

*Geology Department, Faculty of Science, Tanta University, Tanta 31527, Egypt

mtheikal@tu.edu.eg & mohamed.heikal2010@yahoo.com

** M.Sc. Student, Geology Department, Faculty of Science, Tanta University, Tanta 31527, Egypt

.geomohamedelshora@yahoo com

Notes on Meteorites in North Africa Countries

Agenda

Introduction.

Classification of Meteorites.

Meteorites in Egypt.

Meteorites in Libya.

Meteorites in Algeria.

Meteorites in Morocco.

Meteorites in Tunisia.

Introduction

Meteorites are rocks that fall to the Earth from space. Meteorites, large and small, have been hitting our planet for billions of years, and they still hit today. They are collected and intensely studied by scientists. Meteorites are samples from remote parts of our solar system, with histories that extend back billions of years.

Most meteorites come from asteroids, rocky bodies orbiting between Mars and Jupiter. Recently we have learned that a few meteorites have been blasted off the Moon and the planet Mars.

Distinguish between:

Meteoroid : small body in space

Meteor : meteoroid colliding with Earth and producing a visible light trace in the sky

Meteorite : meteor that survives the plunge through the atmosphere to strike the ground...

Meteor Showers

Most meteors appear in showers, peaking periodically at specific dates of the year.

Distribution map of the 182 confirmed meteorite impact structures on Earth .

The Origins of Meteorites

Probably formed in the solar nebula, ~ 4.6 billion years ago.

Almost certainly not from comets (in contrast to meteors in meteor showers!).

Probably fragments of stony-iron planetesimals

Some melted by heat produced by 26Al decay (half-life ~ 715,000 yr).

26Al possibly provided by a nearby supernova, just a few 100,000 years before formation of the solar system (triggering formation of our sun?).

Planetesimals cool and differentiate

Collisions eject material from different depths with different compositions and temperatures.

Meteorites can not have been broken up from planetesimals very long ago

so remains of planetesimals should still exist.

Classification of Meteorites:

1-Chondrites: relatively unaltered, formed as aggregates of primitive solar system material, unmelted asteroids, chondrules usually present, 86% of falls.

2-Achondrites: processed by melting, formed from magma, crust or mantle of asteroid, no chondrules, 8% of falls.

3-Iron meteorites: processed by melting, asteroidal core, 7% of falls.

4-Stony-iron meteorites: processed by melting, core-mantle boundary of asteroid, 1% of falls.

1-

2-

3-

4-

All Meteorites

Undifferentiated

Chondrites

Differentiated

Achondrites Iron MeteoritesStony-Iron Meteorites

Meteorite Classification

Meteorite Classification

Undifferentiated Meteorites

Chondrites

CarbonaceaousChondrites

CI CM CR CO CV CK

R-Chondrites

OrdinaryChondrites

H L LL

EnstatiteChondrites

EH EL

Meteorite Classification

Ach

ondr

ites

MartianMeteorites

Shergottites

Nakhlites

Chassigny

ALH 84001

LunarMeteorites

Aubrites

Ureilites

HED’s(4 Vesta?)

Howardites

Eucrites

DiogenitesAngrites

Differentiated Meteorites

Meteorite Classification

Differentiated Meteorites

IronMeteorites

Octahedrites Hexahedrites Ataxites

Stony-IronMeteorites

Pallasites Mesosiderites

Egypt

Gebel Kamil

22°01’06"N, 26°05’16"E

East Uweinat Desert, Egypt.

Found: 19 February 2009

Classification: (M. D’Orazio, DST-PI; Luigi Folco, MNA-SI) Iron meteorite (ungrouped), Ni-rich ataxite, extensive shear deformation and low weathering.

Specimens: Type specimen of approximately 15 kg and one section atMNA-SI; approximately 5 kg at DST-PI.

Main mass of the recovered specimens at Egyptian Geological Museum (Mineral Resources Authority), Cairo, Egypt.

Fig 1. Kamil Crater, southern Egypt. A: Enhanced true color QuickBird satellite image (22 October 2005; courtesy of Telespazio).B: View of crater from west.

Gebel Kamil

Physical characteristics: A 634 g type specimen, measuring 88·70·55 mm, is flattened and jagged shrapnel with a rough, dark-brown external surface. The surface originally sitting in the desert soil shows some oxy-hydroxides due to terrestrial weathering.

Geochemistry: Composition of the metal (ICP-MS; D’Orazio and Folco, 2003) is Co = 0.75, Ni = 19.8 (both in wt%), Cu = 464, Ga = 49, Ge = 121, As = 15.6, Mo = 9.1, Ru = 2.11, Rh = 0.75, Pd = 4.8, Sn = 2.49, Sb = 0.26, W = 0.66, Re = 0.04, Ir = 0.39, Pt = 3.5, Au = 1.57 (all in ppm). Fig 2. An ~3-kg shrapnel of the associated

iron meteorite.

Isna Place of find: About 100 km SW of

Isna, on the Nile River near Luxor, Egypt “24°50'N, 31°40'E”.

Date of find: 1970

Class and type: Stone. Carbonaceous chondrite (C3, Ornans subtype).

Number of individual specimens: 1, Total weight: 23 kg.

Isna

Circumstances of find: Found by Mohammad El Hinnawi of the Geological Survey of Egypt; main mass is preserved at the Geological Museum, Cairo.

Sources: Letter from Dr. Darwish Mostafa Al-Far, Director, Geological Museum, Cairo, September 2, 1974. R. L. Methot, A. F. Noonan, E. Jarosewich, A. A. DeGasparis and D. M. Al-Far. 1975. Mineralogy, petrology and chemistry of the Isna (C3) meteorite.Meteoritics, 10, 121-131.

Libya

Dar al Gani 005 (CO3)

Latitude: 27°09.39'N

Longitude: 15°57.15'E

Mass (g): 1932

Pieces: 1

Class: CO3

Fayalite (mol%): 15.5 (0.3-85)Ferrosilite (mol%): 3.2 (1.2-14)

Main mass: anonymous finder

Hammadah al Hamra 236 (L4)

Date: 1997

Latitude: 28°31.58'N

Longitude: 13°03.91'E

Mass (g): 8261

Pieces: many

Class: L4

Fayalite (mol%): 24.1

Ferrosilite (mol%): 20.6

Werdama

32°47.839′N, 21°47.228′E

Werdama village, Al-Beda, Al-Jabal Al-Akhdar, Libya.

Fall: 21 May 2006, 7:30 a.m. local time (UT+2)

Classification: Ordinary chondrite (H5), S1, W0.

Type specimens: Main mass of 2 kg (20 cm in length) and 300 g are deposited in GMAlBeda Geological Museum, and 250 g in PDAlBeda; 2 g and four thin sections are deposited in UWroc.

Werdama

History (M. Abu Anbar, TantaU; R. Kryza, UTWroc, T. Przylibski, WTWroc, and G. El Bahariya, TantaU): A bombing sound and cloud of dust was observed in the village during the infall on an apple farm. A crater of 30 × 20 cm and ~10 cm deep. No exact information about the meteorite finder. (probably, the owner of the apple farm). Geologist Mohamed Abu Anbar, TantaU got a few pieces for research from the finder during his visit to the site, shortly after the fall.

Physical characteristics: Reportedly, five pieces were found, with estimated total mass about 4–5 kg. The diameter of the stone was about 25 cm and it had a light gray color, a brown to black fusion crust ~1 mm thick.

Geochemistry: Olivine (Fo79.7, Fa 19.7); pyroxene (Wo 1.3En81.0 Fs17.7); feldspar (Ab 82.8An11.8 Or5.4 ): kamacite (Ni 6.1–9.4 wt%); taenite (Ni =27.4–51.8 wt%).

Algeria

Northwest Africa 778 (H4)

Origin or pseudonym:

El Mahbes

Date: 1999

Latitude: 29°25'N

Longitude: 5°16'W

Mass (g): 9747

Pieces: 3

Class: H4

Fayalite (mol%): 17.5

Type spec mass (g):

70

Main mass: Pani

Northwest Africa 059 (H3.9/4)

Origin or pseudonym: El Aouina Souatar

Latitude: 31°50'N

Longitude: 2°56'W

Mass (g): 27 kg

Pieces: several

Class: H3.9/4

Fayalite (mol%): 19

Ferrosilite (mol%): 16.6

Main mass: JNMC

Comments: Fragments were found in two different, unknown localities, but all of those examined are similar to each other, and all material has been mixed together.

Northwest Africa 4482

Algeria

Find: August 2006

History: G. Hupé purchased the sample in August 2006 in Tagounite, Morocco.

Physical characteristics: The meteorite consists of a total of 30 dark, magnetic fragments containing yellowish-green silicate in a dark brown matrix.The fragments have a combined weight of 5816 g.

Mineral compositions and geochemistry: Olivine (Fa12.2-13.0, FeO/MnO = 41.1-42.5). Oxygen Isotopes: (D. Rumble, CIW) analysis of acid-washed handpicked olivine by laser fluorination gave δ18O = 3.65, δ17O = 1.72, Δ17O = -0.198(all in ‰).

Classification: Pallasite (main group). The original metal in this specimen is almost entirely weathered to iron hydroxides.

Specimens: A total of 20.1 g of sample, one polished thin section and one polished mount are on deposit at UWS. GHupé holds the main mass.

Morocco

Toufassour

29°39′.135 N, 07°44′.958 W

Toufassour, Tata, Morocco

Find: 16 November 2007

Classification: Mesosiderite. Moderately to significantly weathered, depending on the grain size.

Type specimens: 2 polished thin sections and 89.6 g at IZU, one polished thin section and 22 g atUPVI. An anonymous dealer holds 300 g.

Toufassour

Physical characteristics: The fusion crust is absent and the surface appears dark brown. Larger nodules of metal protrude here and there, and larger inclusions of silicates are seen, as greenish spots. Many of the smaller specimens were rich in metal, the phase, which best resisted weathering.

Mineral compositions and geochemistry (EMPA): Pyroxene FeO/MnO =27, En70 Fs26Wo4 to En 59 Fs33Wo8 . Chromite Cr/(Cr + Al) =0.76. Plagioclase Ab7, An 93 . Kamacite, Ni =6%. Merrillite contains significant amounts of MgO.

Tamdakht (H5)

31°09.8′N, 7°00.9′W

Tamdakht, (Ouarzazate) Morocco

Fall: 20 December 2008, 22:37 hrs (local time; UT+00)

Classification: Ordinary chondrite (H5), S3, W0.

Type specimens: A mass of 21 g and one polished section provided by P. Thomas are on deposit at UPVI. 1 piece of 15.8 g provided by L. Labenne and small fragments totaling 20 g at UHAC. Two pieces 10.4 g and 8.6 g at MBE(B. Hoffman), Svend Buhl 2 kg; Meteoritica (PThomas) 2.65 kg; M. Zeroual 20 kg, main mass anonymous finder.

Tamdakht (H5)

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.

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.

Tunisia

Hezma MB91

33°15′N, 10°28′E

Hezma, Tunisia

Find: 31 March 2002

Classification: Ordinary chondrite (L5/6); S3, W1–2.

Type specimen: 12 g and one polished thin section are on deposit at Mün. An anonymous finder, who is Tunisian, holds the main mass.

History and physical characteristics: A single rock of 62 g was found ~10 km south of Medenine in the Hezma area.

Petrography and mineral compositions: (T. Jording and A. Bischoff, Mün) Fa 24 and Fs20.5.

Metameur 001 MB91

33°21′24N, 10°24′32′′E

Metameur, Tunisia

Find: 4 December 2005

Classification: Ordinary chondrite (LL6); S5, W1.

Type specimen: A 30 g sample and one polished thin section are on deposit at Mün. An anonymous finder, who is Tunisian, holds the main mass.

History and physical characteristics: A single stone of 748 g was found ~6 km west of the city of Medenine in the district of the small town of Metameur.

Petrography and geochemistry: (T. Jording and A. Bischoff, Mün): Fa 32 and Fs26.

Metameur 002 MB91

33°21′09N, 10°26′01′′E

Metameur, Tunisia

Find: 25 December 2005

Classification: Ordinary chondrite (H4); S2, W3–4.

Type specimen: A 5 g sample and one polished thin section are on deposit in Mün. An anonymous finder, who is Tunisian, holds the main mass.

History and physical characteristics: A small single stone of 17 g was found in the district of the small town of Metameur.

Petrography and geochemistry: (T. Jording and A. Bischoff, Mün) Fa 18.5 and Fs16.

Metameur 003 MB91

33°24.2′N, 10°27.5′E

Metameur, Tunisia

Find: 25 February 2005

Classification: Ordinary chondrite (L4); S3,W3.

Type specimen: 22 g and one polished thin section are on deposit at Mün. An anonymous finder, who is Tunisian, holds the main mass.

History and physical characteristics: A single rock of 126 g was found in the district of the small town of Metameur.

Petrography and geochemistry: (T. Jording and A. Bischoff, Mün) Fa 26 and Fs19.5±3.2(pyroxene is still slightly unequilibrated).

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