CANARY MUSEUM OF METEORITES has the honor to present the Meteorite NORTHWEST AFRICA 10909 (NWA 10909), the first meteorite discovered by researchers Canaries, and officially classified and recognized.
It is a very interesting meteorite, found by collaborators of the Museum, studied in the Museum and University, and officially recognized by The Meteoritical Society.
On August 20, 2015, some pieces of rocks were located in the Sahara Desert by collaborators of the museum, It was referenced as EUN0815, arrived to this Museum and, by their appearance, appeared to be meteorites.
These were two rocks, one partially covered by a black melt crust and fracture surfaces, and the other covered entirely by a secondary crust.
The director of the Museo Canario de Meteoritos and member of The Meteoritical Society, José García, studied the rocks and in his preliminary report was written.
VISUAL EXPLORATION;
We are faced with two fragmented rocks in which a basaltic structure is clearly perceived, and in some areas a very interesting melting crust; In the case of the larger specimen, the crust is secondary, limited to cover with a thin film partially part of the rock, through which the interior is clearly perceived, since the crust is crystalline. In the smaller specimen the crust is black, perfectly defined in 50% of the surface, the rest of the surfaces are of fracture. No high density is perceived, and in fact, when measured, it is set at about 2.925 grams per cubic centimeter. They are rocks of clearly defined magmatic origins.
MICROSCOPY;
The study was carried out using a STEREO BLUE geological microscope from Euromex, with incident and transmitted LED illumination, and 20 and 40 magnification capacities at high quality analog optical resolution of the parts of the rock capable of documentation and study , Having divided the study of the identified components and parts. We proceed to detail the observations and characteristics found.
METAL PHASE;
The presence of light metal particles is documented. Smaller phases have determined the presence of Ilmenite, Chromite, polymorphic silica and the metallic iron itself.
INTERNAL STRUCTURE;
After cutting the specimen to extract the sample, the crystallization of the components is clearly observed, suggesting its formation in a magmatic chamber. It identifies the clear presence of two minerals in the composition of the rock;
- (2 and 3) Feldspar poor in Calcium.
- (1) Plagioclase rich in Calcium (anortite).
CHONDRULES;
The rock lacks chondrules, being ruled out its membership in the group of chondrites. We observe that it is composed of a crystallized material after its fusion, reason why it is framed within the group of Acondritas.
FUSION CRUST; A characteristic of all meteorites, is the melting crust that forms as a result of the passage through the atmosphere of the rock. This thin layer of molten material acts as a shell on the specimen and is a characteristic sign of them. In the specimen to be studied it is observed that the external melt crust is deep black in the surfaces of maximum exposure to the friction and crystalline in the secondary ones, being observed perfectly in the zones of fracture of the same that let glimpse the underlying whitish material . The composition of the crust is amorphous silica. The regmaglypts observed in the microscopies, on the other hand, are formed by the pressure of the wind on the melted surface during the phase of fall. The specimen is not oriented.
The texture of the surface cortex is therefore 100% compatible with the melting crust of Eucrite type meteorites.
Secondary, crystalline sample. It perceives the internal structure of the components.
Primarly fusion crust. The contraction cracks that we see in the upper microphotography are formed on the melting crust. They often appear as cracking on it when, after extreme melting, the material cools quickly, resulting in a sudden contraction of the material in the solidification phase.
On the other hand, the impact cracks have their origin in the parent body. They appear as a consequence of the impact that the surface of the body undergoes and that results in the ejection of these rocks. The enormous pressures they suffer often crack the rocks, and even more, it translates into fractures that we can see perfectly in the components through a polarizing microscope. These impact cracks usually end up filled with deposited earth material as a result of natural deposits.
DISCUSSION OF RESULTS;
After carefully studying the results of this first analytical phase of the rock, the preparation of polished surfaces of the interior of the meteorite, in the cut areas, that will be studied through the geological microscope of the Technical Department of meteorites conservation of the Museo Canario de Meteoritos, and whose report will be detailed later.
The typical structure of the rock is well known by meteorite researchers, since although it is an unusual type of meteorite (barely 1.4% of the recovered ones), it is very particular. The arrangement of the mineral crystals in the rock, perfectly visible, identifies it directly.
Within the group of Eucritas we can find several types; Breached, cumulated, balanced ... Perhaps the easiest to recognize is balanced, since all the minerals are in a state of crystallization perfectly differentiated. In the existing Spanish bibliography it is detailed; "They have their origin in magmatic chambers of a planetoid, having formed at temperatures above 1100 ºC".
They correspond to a coarse-grained gabbro with majority composition of plagioclase and pyroxene poor in calcium, and presence of pigeonite. Its crystals have a priority orientation frequently, typical of having formed by crystallization of a flow of magma.
After observing the samples under a microscope, evaluating the observations and summarizing the whole, there is no doubt about the nature of the rock.
On the basis of these observations, we can indicate that;
METEORICAL CERTAINTY;
An initial compatibility of 100% for BALANCED EUCRITE is determined.
The international classification of the meteorite is proposed for which a geochemical analysis is required, which was performed by Dr. Jordi Llorca, Professor in inorganic chemistry at the Polytechnic University of Catalonia, where the repository sample will be deposited as required in the official process.
27 grams are separated into two final cut pieces that are sent to the UPC for the accomplishment of the corresponding geochemical and petrographic analyzes in the interest of presenting the meteorite to The Meteoritical Society.
This is how the analytical phase of the meteorite begins.
November 4, 2015.
GEOCHEMISTRY REPORT.
After the shipment of the samples of the referenced rock EUN-0815 in quantity of 27.4 grams to the Polytechnic University of Catalonia (UPC), have been analyzed by Dr. Jordi Llorca (Department of Inorganic Chemistry), having yielded the following result geochemical.
GEOCHEMICAL COMPOSITION;
Orthopyroxene (Opx)
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Ferrosilite (Fs)
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57.4 (+-0.9) mol %
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Wollastonite (Wo)
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2.2 (+- 1.4) mol %
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FeO/MnO
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32 (+- 1)
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n
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19
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Plagioclase (Plg)
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Anortite (An)
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87.1 (+-2.6) mol %
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n
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21
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Minor phases present Ilmenite, polymorphic silica and troilite.
CLASSIFICATION;
The specimen to be studied is a MONOMICT BASALTIC EUCRITE.
DATA;
According to the current scientific literature, the eucrites are igneous rocks formed in the magmatic chamber of the VESTA asteroid (4), at temperatures above 1,100 ºC and by crystallization of the magma itself.
On November 11, 2015, the information corresponding to the editor of the Meteoritical Bulletin is sent so that the new meteorite can be recognized by the Nomenclature Committee of The Meteoritical Society. Below we present the information submitted in the first instance.
After having analyzed and collected all the pertinent information to the discovery of the meteorite object of this study, the information is sent to its classification in the Meteoritical Bulletin.
The information transmitted is summarized below, being certified in its veracity.
They have intervened in the present process;
Dr. Jordi Llorca, Professor in Inorganic Chemistry. Universitat Politécnica de Catalunya UPC. Barcelona.
José García, Director of the Canary Museum of Meteorites. Las Palmas de Gran Canaria.
The documentation is sent to The Meteoritical Society to initiate the process of international classification of the new meteorite, sending the following official data of the finding;
PROPOSED NAME; NWA NorthWest Africa (10909)
COUNTRY; Western Sahara
STATE; Morocco
SITE; Km 112 south of Tinduf
Purch. Place; Laayoune
FALL: no
Fall date; August 2015
Purch. Date; September 2015
Mass; 924.2
Pieces: 6
Class; monomict eucrite
W grade; low
Fs; 57.4+/-0.9 (N=19)
Wo; 2.2+/-1.4 (N=19)
Type spec mass; 20
Finder; José García & Javier J. Franco
Classifier; J.Llorca, UPC
Type spec loc; UPC
Main mass loc; MCM (Museo Canario de Meteoritos, P.O. Box 3, Agüimes 35260 Las Palmas, Spain)
Writeup history; Six completes stones partialy covered with a dark brown fusion crust and secondary fusion crust was found by nomads in Sahara desert. The stones was purchased for study by J. García, Manager of Canary Museum of Meteorites.
Writeup physical; SPECIMENS; Main mass; 201.3 gr; Javier Franco collection, Las Palmas de Gran Canaria, Spain. 90.9 gr; Museo Canario de Meteoritos, José García. Las Palmas de Gran Canaria, Spain. 20 gr; UPC (Universitat Politécnica de Catalunya), Barcelona.
DESCRIPTION; 6 completes stones covered with fusion crust and secundary fusion crust was found in the desert by nomad. The stones (201.3, 110.9, 121.7, 127.1, 100.3, 152 grams) were sent to Museo Canario de Meteoritos for study. After the first studies, and with the clear suspicion of their nature, some grams were sent to Universitat Politecnica de Catalunya, in Barcelona, where analysis was performed by Dr. Jordi Llorca in 2015 october.
Writeup petrog; The meteorite displays a basaltic texture of up to 1.5 mm sized exsolved pyroxenes and equally sized lath-shaped calcic plagioclase. Minor phases include chromite, SiO2 polymorphs, ilmenite and metallic iron
Writeup class; The stones are clasified as a monomict eucrite.
Writeup specimens; Specimens are in Museo Canario de Meteoritos (MCM) and Javier Franco Collection (Las Palmas G.C.) Spain. There are 20 grams in UPC (Barcelona).
Submitter; Jose García
The Meteorite was officially approved on November 23, 2016 and published on the 26th in The Meteoritical Database.
| Northwest Africa 10909 | |||||||||||||||||||||||||||||||
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| Basic information | Name: Northwest Africa 10909 This is an OFFICIAL meteorite name. Abbreviation: NWA 10909 Observed fall: No Year found: 2015 Country: Western Sahara Mass: 924 g | ||||||||||||||||||||||||||||||
| Classification history: |
This is 1 of 183 approved meteorites classified as Eucrite-mmict. | ||||||||||||||||||||||||||||||
| Comments: | Approved 26 Nov 2016 | ||||||||||||||||||||||||||||||
| Writeup |
Writeup from MB 105:
Northwest Africa 10909 (NWA 10909)
Morocco, Western Sahara
Find: 2015 Aug
Classification: HED achondrite (Eucrite, monomict)
History: Six complete stones covered with dark fusion crust were found in the desert by a nomad. The stones (originally 201.3, 110.9, 121.7, 127.1, 100.3, and 152 g) were sent to MCM for study. After the first studies, several grams were sent to UPC, where analysis was performed by Dr. J. Llorca in October 2015.
Petrography: The meteorite displays a basaltic texture with up to 1.5 mm sized exsolved pyroxenes and equally sized lath-shaped calcic plagioclase. Minor phases include chromite, SiO2 polymorphs, ilmenite and metallic iron.
Geochemistry: (J.Llorca, UPC) Orthopyroxene; Fs57.4±0.9, Wo2.2±1.4, FeO/MnO = 32±1, n=19. Plagioclase; An87.1±2.6, n=21.
Classification: Monomict eucrite.
Specimens: The remaining masses are in the private collection of Javier Franco, Las Palmas de Gran Canaria, Spain, and 90.9 g at MCM. Repository sample: 20 g UPC.
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| Data from: MB105 Table 0 Line 0: |
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| Institutions and collections | UPC: Institut de Tècniques Energètiques, Universitat Politècnica de Catalunya Diagonal 647, ed. ETSEIB, 08028 Barcelona, Spain, Spain (institutional address; updated 3 May 2015) MCM: Museo Canario de Meteoritos Las Palmas de Gran Canaria, Spain (institutional address; updated 26 Nov 2016) | ||||||||||||||||||||||||||||||
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| References: | Published in Meteoritical Bulletin, no. 105, in preparation (2016) | ||||||||||||||||||||||||||||||
Meteoritical Bulletin Information for MCM
| Abbreviation: | MCM |
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| Collection type: | Institutional collection |
| First bulletin with this collection: | 105 |
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| Shipping address: | Museo Canario de Meteoritos Las Palmas de Gran Canaria |
| Country: | Spain |
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| Revision date: | 2016-11-26 |
Main mass, 201.3 grams. Full oriented piece with flow lines.
Mass of 110.9 grams. Full piece.
Mass of 121.7 grams.
Mass of 127.1 grams.
Mass of 90.9 grams of the Canary Museum of Meteorites.
Mass of 152 grams.
MASSES FOR SALE FOR COLLECTIONS;
The Canary Museum of Meteorites and the Collection of Meteorites Javier F. bring for sale some pieces of the new meteorite NWA 10909 for those collections that wish to have them. To acquire some of them, you can see the masses available by clicking on the links below exposed;
For more masses and other, please contact to direccion@museocanariodemeteoritos.com and we will send you the complete catalog. We have more than 50 pieces for sale in different weight.
