SQU Journal for Science, 2017, 22(1), 29-39 DOI: http://dx.doi.org/10.24200/squjs.vol22iss1pp29-39 2017 Sultan Qaboos University 29 Review of the Sayh al Uhaymir (SaU) 005, Plus Pairings, Martian Meteorite from Al Wusta, Oman Arshad Ali1*, Sobhi Nasir1, Iffat Jabeen2 and Ahmed Al-Rawas3 1Earth Sciences Research Centre (ESRC), Sultan Qaboos University, P.O. Box: 36, PC 123, Al-Khoud, Muscat, Sultanate of Oman; 2Department of Earth Sciences, Western University, 1151 Richmond St. N., London, ON, N6A 5B7 Canada; 3Department of Physics, College of Science, Sultan Qaboos University, P.O. Box: 36, PC 123, Al-Khoud, Muscat, Sultanate of Oman. *Email: arshadali@squ.edu.om. ABSTRACT: Al Wusta is a desert area in the Sultanate of Oman which is famous due to the discovery of a number of Martian and Lunar meteorites since the start of the present millennium. According to the Meteoritical Bulletin database, 137 approved Martian meteorites have been found worldwide, including 17 from Oman (4 from Zufar, 13 from Al Wusta region). Interestingly 11 finds in the last 15 years have been of Sayh al Uhaymir (SaU) 005 and its pairings. These finds (estimated mass = 11.2 kg) are linked to 10 search expeditions carried out between November 26, 1999 and March 2, 2014 by the Swiss group from the University of Bern and several anonymous meteorite hunters. The bulk of these meteorites (~97%) is in the possession of anonymous collectors, negatively affecting Oman’s natural heritage and denying further research opportunities, given their associated scientific value. SaU 005 and its pairings belong to the shergottite group of the Shergotty-Nakhla-Chassigny (SNC) meteorites, originating from various depths within the Martian mantle. We discuss the recently published oxygen isotope data of bulk and mineral fractions of SaU 008 recovered during the very first expedition in 1999 in the context of other shergottites found in Oman. The bulk oxygen isotope data of SaU 008 and Dhofar 019, another Martian meteorite from Oman, show a narrow range in δ18O values. Their Δ17O values are remarkably close to identical and fall linearly on a Martian fractionation line above the terrestrial fractionation line (TFL) by + 0.32‰, suggesting that Mars’ mantle is homogeneous in oxygen isotopes. Petrographic and mineralogical data of SaU 005 and other pairings published in the Meteoritical Bulletin are compiled, and it is noted that all the meteorites are identical and are likely paired. The story behind these rare extra-terrestrial specimens demands a local meteorite museum and preliminary testing laboratory at Sultan Qaboos University (SQU) to protect this treasure trove of Omani heritage. Keywords: Mars; Oxygen isotopes; SNC meteorites; Oman. المريخية وقريناتها، المنطقة الوسطى، سلطنة عمان 005 مراجعة لنيازك سيح األحيمر أحمد الرواس و عفت جابيين ،صبحي نصير، أرشاد علي في سلطنة عمان باكتشاف عدد من النيازك المريخية والقمرية منذ مطلع القرن بالمنطقة الوسطى الصحراوية تشتهر منطقة سيح األحيمر :ملخصال منطقة المن 13من ظفار، 4نيزك من عمان ) 17نيزك مريخي في العالم تتضمن 137الحالي. وطبقا الى بيانات نشرة النيازك فقد نم العثور على رحالت 10. عثر على هذه الموجودات خالل األحيمر خالل الخمس عشر سنة الماضيةور عليها في سيح نيزكا تم العث 11الوسطى(. ومن المثير ان . من المحتمل ان 2014مارس 2الى 1999نوفمبر 26استكشافية من قبل مجموعة جامعة بيرن السويسيرية وكذلك صيادو النيازك خالل الفترة من ( في أيادي %97تقع معظم نيازك سيح األحيمر المريخية )لذي وقع في الصحراء. زك األصلي اكلغم( الى نفس الني 11.2تعود جميع هذه النيازك ) ورديفاتها الى مجموعة الشيروجيت ضمن نيازك 005تتبع نيازك سيح األحيمر مجهولين، وهذا يؤثر على التراث العماني الطبيعي وقيمته العلمية. ة. نناقش في هذا البحث بيانات نظائر االوكسيجين المنشورة لمعادن وتركيب نيزك شاسجني ذات األصل المريخي من اعماق مختلف -نخال- الشيروجيت مقارنة مع النيازك المريخية االخرى من عمان. تظهر بيانات نظائر 1999وهو من اول النيازك التي عثر عليها خالل عام 008سيح االحيمر وتقع على خط 17. هذه البيانات متشابهة في قيم االكسيجين 18يم االكسيجين نطاق ضيق من ق 008وسيح االحيمر 019لنيزك ظفار 18االكسيجين تم تجميع ومناقشة البيانات % مما يدل على تجانس نظائر االكسيجين في المريخ. 0،32تمايز المريخ وفوق خط تمايز الصخور القارية بقيمة + تواجد نيازك سيح االحيمر وتوزعها عمل متحف خاص . يتطلب ورديفاتها 005يمرالمعدنية والمجهرية المنشورة حول النيازك المريخية من سيح األح .بالنيازك ومختبر متخصص لها في الجامعة لحماية التراث العماني ش ن ش(. ) شاسجنيت-نخليت -شيروجيتالمريخ، نظائر األكسجين ، نيازك :مفتاحيةالكلمات ال ARSHAD ALI ET AL 30 1. Introduction eteorites are extra-terrestrial objects that land on Earth after extensive travel in space. Our Earth is constantly showered by chunks of meteorites from the asteroid belt and neighboring planets. These alien rocks heat up when they enter the Earth’s atmosphere due to friction and give them a dark and shiny surface called a fusion crust. This unique visual characteristic helps in tracking down meteorites particularly in flat, light-colored deserts due to the color contrast [1]. The Sultanate of Oman has been the hub of meteorite search since the start of this millennium. In the early years, private collectors took advantage of the free trafficking of meteorites across Oman’s borders, leaving the country deprived of its national treasure [1]. Fortunately, Oman has recently regulated the export of meteorites for the protection of future meteorite finds; however, damage has already been done to some precious samples including Sayh al Uhaymir (SaU) 005 and most of its pairings. Al Wusta is the desert area in Oman where several Martian and Lunar meteorites have most commonly been spotted by the commercial meteorite dealers and international scientific teams. Until recently (April 2016), Meteoritical Bulletin has reported 137 approved Martian meteorites including 17 from the Sultanate of Oman (Table 1). Table 1. Martian meteorite finds from the Sultanate of Oman. Approved Name Classification Find Location Year Mass (g) Dhofar 019 Shergottite-basaltic (ol phyric) Zufar 2000 1056 Dhofar 378 Shergottite-basaltic Zufar 2000 15 Dhofar 1668 Shergottite Zufar 2011 6.1 Dhofar 1674 Shergottite Zufar 2010 49.2 Jiddat al Harasis 479 Shergottite Al Wusta 2008 553 Jiddat al Harasis 910 Shergottite Al Wusta 2011 27 SaU 005 Shergottite-basaltic (ol phyric) Al Wusta 1999 1344 SaU 008 Shergottite-basaltic (ol phyric) Al Wusta 1999 8579 SaU 051 Shergottite-basaltic (ol phyric) Al Wusta 2000 436 SaU 060 Shergottite-basaltic (ol phyric) Al Wusta 2001 42.3 SaU 090 Shergottite-basaltic (ol phyric) Al Wusta 2002 94.8 SaU 094 Shergottite-basaltic (ol phyric) Al Wusta 2001 223 SaU 120 Shergottite-basaltic (ol phyric) Al Wusta 2002 75 SaU 125 Shergottite-basaltic (ol phyric) Al Wusta 2003 31.7 SaU 130 Shergottite-basaltic (ol phyric) Al Wusta 2004 279 SaU 150 Shergottite-basaltic (ol phyric) Al Wusta 2002 107.7 SaU 587 Shergottite (ol phyric) Al Wusta 2014 4.7 Since the year 2000, the rate of meteorite finds has been rapid, triggering a delay in the reporting and classification of an exponentially increasing number of new samples [1]. For classification of a new meteorite, a submission is made to the Meteoritical Bulletin in the form of a template filled with some basic details such as find/fall location, date of recovery, latitude and longitude and mass, along with some visual observations of the sample at the time of recovery. Quite often, further petrographic, mineralogical, geochemical and isotopic data is also included for classification of the meteorite. These unique samples may represent tiny pieces from the core or mantle of other planets; providing us with the opportunity to learn more about the Earth’s interior, given that the Earth is inaccessible at such depths. In order to learn about the origin of extraterrestrial materials in space, multiple stable isotope ratios of oxygen are commonly utilized. Oxygen is the most abundant element in the Earth’s crust and mantle and the third most abundant, after hydrogen and helium, in the Solar System [2]. It has three isotopes; 16O, 17O and 18O, differing in their masses and abundances in nature. The lightest isotope (16O) comprises > 99% of the oxygen abundance in nature. Oxygen isotope ratios are conventionally expressed using the delta (δ) notation as: δ18O = (18Rsample – 18RVSMOW)/ 18RVSMOW where 18R =18O/16O and δ17O = (17Rsample – 17RVSMOW)/ 17RVSMOW where 17R =17O/16O Delta values are commonly expressed as permil (i.e., ‰). When oxygen isotope compositions of terrestrial silicate rocks and minerals are plotted on a three-isotope diagram of 18O and 17O values, the resultant straight line of slope- 1/2 [3, 4] is commonly referred to as the terrestrial fractionation line (TFL). The TFL serves as a reference line to evaluate the provenance of meteorites. Offsets in oxygen isotope ratios relative to the TFL are used to characterize meteorite groups (Figure 1). A meteorite sample is mostly made up of silicate minerals and in order to liberate all the oxygen from it, the laser-fluorination technique is used. This method has been used globally at various laboratories for precise 17O and 18O measurements of terrestrial rocks [5-13] and meteorites [14-19] since the 1990s. The M REVIEW OF THE SAYH AL UHAYMIR (SAU) 005 31 significance of triple oxygen isotopes is unprecedented in the realm of geochemistry and cosmochemistry, and the study of their relationship has found widespread and diverse applications in various fields including meteoritics. This system provides key information about the origin of rocks and the processes they underwent in the past. Oxygen isotope data of samples formed from any terrestrial chemical or physical process (e.g., melting-crystallization or evaporation-condensation) fit on the TFL having a slope of ~0.52 [4]. Conventionally, the offsets (i.e., 17O; negative or positive) from the TFL are calculated (17O = δ17O – 0.52 δ18O; [20]) to study the unique oxygen isotope signatures of meteorites. However, Miller [21] proposed the use of prime notation (′17O, ′18O), which takes into account the linear function relationship between 17O and 18O for a sample measured with respect to a reference, instead of the conventional approximation of a power law function. Construction of the TFL, based on various types of terrestrial materials, is a pre-requisite to conduct geochemical and cosmochemical studies in a stable isotope laboratory. Over half a century ago, [22] started reporting oxygen isotope data of various types of meteorites using the conventional method of oxygen extraction by fluorination (e.g., F2, HF, BrF5, ClF3) of samples at 500-700 oC in Ni- tubes. More recent studies have employed affordable and reliable laser systems (e.g., CO2 & Nd:YAG lasers) for heating the samples in a fluorinating atmosphere [5, 19, 23-25]. Compared to conventional fluorination methods, the laser fluorination technique is advantageous owing to its significant sample size reduction (1000-1500%) and improved reaction efficiency (e.g., 300%) without compromising the precision and accuracy of the data. It also has the considerable benefit of operating at high temperatures in order to react refractory mineral phases such as olivine and some oxides. In addition, oxygen produced by conventional methods typically involves conversion to CO2 gas by reacting with hot graphite rods prior to analysis on a mass spectrometer. This requires further C-isotope corrections than if using oxygen gas as an analyte. As a result, the laser-fluorination technique is a preferred method to extract oxygen and measure triple oxygen isotopes online or offline. We include the Sayh al Uhaymir (SaU) 005 meteorite and its pairings in this review to assess their oxygen isotope data of bulk materials and separated fractions, along with published data of other Martian meteorites from Oman. In addition, an account of the collection history and petrographical/mineralogical details of SaU 005, plus pairings, are compiled and discussed. 2. Analytical Description A comprehensive study has recently been carried out to analyze various samples from the Shergotty-Nakhla- Chassignite (SNC) group, including meteorites found in Oman (e.g., SaU 008 and Dhofar 019), for precise triple oxygen isotope measurements using the laser fluorination technique coupled with the mass spectrometer [19]. For bulk analysis, this study utilized a minimum of 50-100 mg of sample aliquot of both SaU 008 and Dhofar 019 meteorites to make powder. A small portion of the powdered material was pre-treated with 6M HCl at 70 °C for 2-3 minutes in order to remove the potential terrestrial weathering products, and so to obtain the actual isotope data of each meteorite. Acid-treated and untreated bulk materials (1-2 mg) were loaded on the sample holder and placed in the sample chamber. After complete evacuation of the vacuum line, a reaction was performed by heating the sample with a 25W CO2 laser (10.6 µm wavelength; Merchantek, Bozeman, MT, USA; Model MIR10-25) in a BrF5 atmosphere to extract oxygen gas. Similarly, separated fractions such as pyroxene and olivine for SaU 008 and maskelynite for Dhofar 019 were also irradiated with the laser to produce oxygen gas from the mineral framework. Later, oxygen gas was purified using cryogenic metal traps and a heated KCl salt trap, giving yields of better than 95%. The triple oxygen isotope measurements were performed using a Delta V Plus mass spectrometer in dual inlet mode integrated with Isodat3.0 software for system controls and data acquisition. Data were reported as delta notation (δ) referenced to the Vienna Standard Mean Ocean Water (VSMOW). A detailed analytical methodology is described in [19]. ARSHAD ALI ET AL 32 Figure 1. Pictorial illustration of the triple oxygen isotope diagram. Slope-1/2 line is referred to as the Terrestrial Fractionation Line (TFL); triple oxygen isotope data from planet Earth, moon and Enstatite Chondrites fall on the TFL; however, data from other extra-terrestrial bodies either fall above or below the TFL. Some meteorites (with their place and year of fall) are shown for comparison. Right bottom of the illustration (methodology) displays an image of a laser and BrF5 (Br attached to 5 fluorine atoms) for extracting oxygen gas from the crystal framework (e.g., olivine) of a meteorite (image: pallasite) followed by isotopic measurements using a mass spectrometer. Individual images are taken from the Internet. This illustration is not to scale. 3. Discussion Sample preparation and pre-treatment After extensive space travel, meteorites encounter terrestrial conditions for long periods of time, of thousands of years and more. Terrestrial weathering will result in shifts in 17O of a meteorite towards the TFL compared to its actual value, due to the formation of secondary carbonate and oxide minerals. For example, meteorite data below the TFL, will move upwards, as in the case of pallasites, and that above will move downwards, as with SNC meteorites, due to terrestrial weathering, so there is a two directional shift around the TFL depending on what type of meteorite is under investigation. If weathering is non-terrestrial, e.g., having occurred on the surface of Mars, the trend will be different as evidenced by [26] from the Lafayette meteorite. They reported heavier δ18O and higher ∆17O values for Low-T mineral (e.g., Iddingsite) formed on the surface of Mars. Antarctica has a large population of meteorites which have remained preserved under the ice cover for extended periods of time. A recent study [18] has reported contrasting weathering trends in Antarctic and non-Antarctic meteorite finds. A reasonable interpretation of this paradigm is that whenever there is terrestrial weathering in a non-Antarctic environment, the data will go up due to secondary carbonate and oxide minerals, whilst in an Antarctic environment, the data of weathered meteorites will go down possibly due to Antarctic snow which is extremely low in δ18O compositions [e.g., Longhovde area has -30‰; 27], that could become incorporated into the weathering products. Oxygen isotope data of SNC meteorites from the Sultanate of Oman The published oxygen isotope compositions of SNC meteorites from the Sultanate of Oman are compiled in Table 2 and plotted in Figure 2. The few data points showing a scatter in ∆17O values (Figure 2) are likely to be REVIEW OF THE SAYH AL UHAYMIR (SAU) 005 33 associated with either terrestrial weathering (assuming that samples were analyzed without acid-treatment given the absence of such details reported in the literature) or due to analytical artifacts in δ17O measurements (17O abundance = 0.04%; see Figure 1). However, recently researchers [19] have analyzed SNC meteorites and they have found no significant variation in ∆17O values between the untreated and acid-treated samples. Their data did not support the idea of scatter in ∆17O due to a weathering phenomenon. However, it is noted that the data of acid-treated samples are skewed towards lower values. They argued that the discrepancy is caused by the elimination of carbon dioxide gas from the carbonates (i.e., originated on Mars surface) after acid treatment. Carbonates are typically heavy in oxygen isotopes [28-31]. A recent work [19] also commented on the most common interferences (m/z = 33) on δ17O values. Traces of fluorination by-products such as NF3 and CF4 are caused by inefficient removal of these species when they are trapped with extracted oxygen gas on adsorbing media (i.e., molecular sieves 13X and 5Å) at liquid-N2 temperature. These analytical artifacts directly affect 17O data. Table 2. Triple oxygen isotope compositions of bulk and separated fractions of SNC meteorites from the Sultanate of Oman. Sample Type δ17OVSMOW (‰) δ18OVSMOW (‰) Δ17O (‰) N Reference Dhofar 019 bulk 2.299±0.102 (SE) 3.826±0.189 (SE) 0.310±0.006 (SE) 3 [19] Dhofar 019 bulk 2.569 4.474 0.216 ̶ [32] Dhofar 019 bulk* 2.890 4.937 0.325 2 [19] Dhofar 019 bulk 2.99 5.4 0.18 ̶ [33] Dhofar 019 mask 2.918 4.985 0.328 2 [19] Dhofar 378 bulk@ 2.52 4.46 ̶ ̶ [34] JaH 479 bulk§ 2.951 5.070 0.315 ̶ [35] SaU 008 bulk* 2.696 4.544 0.335 2 [19] SaU 008 bulk 2.212 3.677 0.300 2 [19] SaU 008 px 2.673 4.533 0.318 2 [19] SaU 008 ol 2.518 4.223 0.324 2 [19] SaU 094 bulk§ 2.51 4.25 0.28 ̶ [36] SaU 0150 bulk§§ 2.78 4.74 ̶ ̶ [37] ol = olivine. px = pyroxene. mask = maskelynite. JaH = Jiddat al Harasis. SaU = Sayh al Uhaymir. SE = standard error. SE calculated by dividing the SD (standard deviation) with the square root of N. N = number of individual runs. Samples marked with asterisk (*) were analyzed without acid treatment. @oxygen isotope data were obtained by T. K. Mayeda and R. N. Clayton (University of Chicago, USA). §oxygen isotope data were obtained by I. Franchi (Open University, UK). §§oxygen isotope data were obtained by R. N. Clayton (University of Chicago, USA). Sayh al Uhaymir (SaU) 005 Recovery Site Sayh al Uhaymir (SaU) 005 and pairing meteorite finds are associated with several years of searches in the desert of Al Wusta, Oman. The latitude and longitude values, number of pieces, total mass recovered during each search and details of the finder are given in Table 3. The greatest part of the total mass of SaU 005 and pairings was recovered in the early years (1999-2000) and the tiniest mass of all (4.7 g) was found in the latest search carried out in 2014 (Figure 3). The heaviest pieces of all the finds were scattered in the middle of the find locations spanning an area of 2 km wide and 4 km long (Figure 4). It seems plausible that SaU 005 suffered shattering twice: first in the Earth’s atmosphere due to heat generated by friction, and then by break-down due to impact on the ground causing heavily cracked pieces to fall apart within the vicinity of the larger stones (e.g., SaU 005 and SaU 008). For example, a lone piece of SaU 120 (75 g) has a well preserved fusion crust [37] which could have broken down from the original rock at a certain height in Earth’s atmosphere. Consequently, the stone would have had sufficient time to react with the ambient air due to frictional heat, and as a result, developed a thick fusion crust. However, SaU 150 [37] shows relatively thinner fusion crust supporting the idea that this meteorite did not have sufficient interaction time to develop a thick fusion crust, as generally observed in other pieces (e.g., SaU 150). Moreover, SaU 587 [38] is characterized by the presence of partial fusion crust, owing to its possible break down after impact with the ground. ARSHAD ALI ET AL 34 Figure 2. Comparison plot of δ17O vs. δ18O data published for bulk materials and separated fractions (i.e., px, ol, mask) of SNC meteorites from the Sultanate of Oman. Solid and dashed lines represent the Martian fractionation line [MFL; 19] and standard error respectively. UT = untreated. AT = acid-treated. px = pyroxene. ol = olivine. mask = maskelynite. TFL = terrestrial fractionation line. Other data sources: [32-33, 35-36]. Table 3. Sayh al Uhaymir (SaU) Martian meteorite finds in chronological order from the Sultanate of Oman. Name Location Date Latitude (N) Longitude (E) Pcs Mass (g) Finder/Main mass SaU 005 Al Wusta Nov. 26, 1999 20°59.76´ 57°19.55´ 3 1344 Anonymous/Anonymous SaU 008 Al Wusta Nov. 26, 1999 20°58.83´ 57°19.14´ 2 8579 Anonymous/Anonymous SaU 051 Al Wusta Aug. 01, 2000 20°58.435´ 57°19.248´ 1 436 Anonymous/Anonymous SaU 094 Al Wusta Feb. 08, 2001 20°59.469´ 57°20.326´ 1 223.3 M. H. & L. M. (Bern)/NMH SaU 060 Al Wusta Jun. 27, 2001 20°58.8´ 57°19.1´ 1 42.3 M. H. & L. M. (Bern)/NMH SaU 090 Al Wusta Jan. 19, 2002 21°00.0´ 57°19.2´ 2 94.8 Anonymous/Anonymous SaU 150 Al Wusta Aug. 10, 2002 20°59.313´ 57°19.117´ 1 107.7 R. & S. B. (Bart)/Bart SaU 120 Al Wusta Nov. 17, 2002 21°00.2´ 57°19.3´ 1 75 Anonymous/Anonymous SaU 125 Al Wusta Nov. 19, 2003 21°00.4´ 57°19.3´ 1 31.7 Not Given SaU 130 Al Wusta Jan. 11, 2004 21°00.2´ 57°19.1´ 4 278.5 Not Given SaU 587 Al Wusta Mar. 02, 2014 21°00.764´ 57°19.238´ 1 4.7 Anonymous/Anonymous M. H. & L. M.= Marc Hauser & Lorenz Moser. Bern = University of Bern, Switzerland. NMH = Natural History Museum Bern, Switzerland. R. & S. B. = Rainer & Sven Bartoschewitz. Bart = Bartoschewitz Meteorite Laboratory, Germany. Pcs = pieces. 0.15 0.20 0.25 0.30 0.35 0.40 0.45 3.5 4.0 4.5 5.0 5.5 Bulk-UT + Fractions [19] Bulk-AT [19] Other Published Data ∆ 1 7 O δ18OVSMOW(‰) TFL SaU 008 - ol SaU 008 - px Dhofar 019 - mask Dhofar 019 - bulk SaU 008 - bulk REVIEW OF THE SAYH AL UHAYMIR (SAU) 005 35 Figure 3. Pie chart showing recovered mass of the Sayh al Uhaymir (SaU) 005 Martian meteorite and its pairings found in various years from the Sultanate of Oman. SaU 005+pairings find history and review of published data Extremely fresh pieces of SaU 005/008 were recovered by anonymous meteorite hunters on November 26, 1999 (Table 3). However, a few cracks partially filled with calcite were seen owing to the terrestrial weathering processes. Both meteorites show porphyritic texture with large olivine phenocrysts (Table 4) in a fine-grained groundmass of pigeonite and maskelynite [39]. Olivine shows mosaicism and planar deformation and clinopyroxene grains (pigeonite) that are also twinned and fractured, all of which are possibly associated with the strongly shocked (S5) nature of these finds. In the following year, anonymous finders tracked down a piece of SaU 051 which is considered to be a pairing of SaU 005/008, based on texture, mineralogy (Table 4) and proximity in find locations. A shock stage S5 is assigned to this find and calcite veins [36] are also reported. The next year 2001, Marc Hauser and Lorenz Moser from the University of Bern, Switzerland, found SaU 060 and SaU 094, one stone apiece, during two separate expeditions. The main mass of the meteorites is curated at the Natural History Museum Bern, Switzerland. The mineralogical characteristics of these samples, e.g., large olivine phenocrysts (ave. max. size = 1.5mm) embedded in a fine-grained (ave. max. size = 0.3mm) groundmass of maskelynite and pigeonite [36], are comparable to those of SaU 005/008/051 and they are considered as pairs [40]. Moreover, both pieces display the same shock stage (S5) associated with shock twining, mosaicism and local oxidation in olivine [36]. It is also reported that SaU 094 has abundant partially recrystallized veins and pockets containing glass vesicles due to shock melting [36]. Compared to SaU 094, SaU 060 is slightly weathered with small rusty pockets of Fe-hydroxide, a likely replacement of an unknown pre-existing phase [36]. The porosity of meteorites plays an important role in terrestrial weathering caused by water and moisture. X-ray tomographic analysis of SaU 094 revealed pores of up to 3mm size and they constitute 0.4 vol% of the sample [36]. Sm-Nd data of ten fractions (e.g., wr, px) from SaU 005/094 form a linear array between 147Sm/144Nd and 143Nd/144Nd ratios yielding a crystallization age of 445±18 Ma [41]. Later, it was discovered that SaU 008 and SaU 094 have ε142Nd values of 0.647 and 0.569 [42] respectively which is significantly higher than the average chondritic (i.e., -0.18 ± 0.08) and terrestrial standard (i.e., 0 ± 0.03) values [43-44]. The ε142Nd enrichment in these samples is interpreted as being derived from an incompatible-trace- element-depleted source formed during the first 500 Ma of evolution of Mars. 1999 2000 2001 2002 2003 2004 2014 ARSHAD ALI ET AL 36 Figure 4. (a) A location map taken from [45]. (b) Find locations of various SaU 005 and pairing meteorites from Al Wusta, Oman. The recovery area is 2 km x 4 km. Approved names of all finds are shown with recovered masses (g) in brackets, along with number of pieces. Reds are the main mass of these fin ds, recovered during the first expedition in 1999. Purples were found as one piece having a mass of over 100g. Four more pieces of SaU 090/120/150 were recovered during three separate searches in 2002. Two of the three searches were performed by anonymous hunters who recovered two pieces of SaU 090 and one piece of SaU 120, while in the third search Rainer and Sven Bartoschewitz from Bartoschewitz Meteorite Laboratory, Germany were successful in finding a piece of SaU 150 (Table 3). No textural and petrographic details of SaU 090 are provided in the Meteoritical Bulletin [34]. On the other hand, SaU 120 is reported as a gray-greenish stone with well-preserved fusion crust. The textural characteristics of SaU 120 are identical with other previously found pieces such as SaU 005/008/051/060/090/094 [37]. The SaU 150, a find by Rainer and Sven Bartoschewitz, was studied in detail for its © 2016 Cnes/Spot Image 2885 SaU587 (4.7 g) 21 00.764,57 19.238 SaU125 (31.7 g) SaU120 (75 g) 4 x (278.5 g) SaU130 SaU090 (94.8 g) x 2 SaU005 (1344 g) x 3 SaU150 (107.7 g) SaU094 (223.3 g) SaU008 (8579 g) x 2 SaU051 (436 g) SaU060 (42.3 g) (a) (b) REVIEW OF THE SAYH AL UHAYMIR (SAU) 005 37 geochemistry and oxygen isotopes [37]. It is an olive-brown colored stone of relatively angular shape with one small area of thin black-brown fusion crust. This piece was recovered on a Miocene fresh-water limestone gravel plateau. It displays a porphyritic texture with 2mm sized olivine phenocrysts embedded in a matrix of feldspathic glass and pigeonite. Minor Ca-poor pyroxenes with a composition of En65-66Fs34-35 are observed. Recrystallization of shock-melt veins and pockets is also noticed. A single piece of the SaU 125 was found by an unknown person in 2003 and it is considered as paired with SaU 005/008/051/060/090/094/120 [46]. The very next year, four pieces of SaU 130 were recovered by an anonymous finder and these samples were cited as paired with all the previously found meteorites including SaU 005/008/051/060/090/094/120/125 [46]. A compilation of petrographic, geochemical and isotopic data of SaU 005 and pairings found until 2004 is available at the Martian Meteorite Compendium [47]. Lastly, after a nine- year hiatus, a small piece (4.7 g) of the SaU 587 was recovered from the close vicinity of the previous find locations by an anonymous collector in early 2014. According to the Meteoritical Bulletin [38], it is a small greenish-gray stone with some fusion crust. Typical mm-sized olivine phenocrysts set within a fine-grained basaltic groundmass, dominantly of pigeonite and maskelynite, show a porphyritic texture. A high degree of shock metamorphism is associated with strong mosaicism of olivine, conversion of plagioclase to maskelynite and abundant melt veins and pockets [38]. Furthermore, intense fracturing is observed. However, this sample is moderately weathered, with only a few of the larger cracks being partially filled with calcite. It is paired with the SaU 005/008. Owing to the discovery of 10 pairings of the SaU 005 (Table 3) from the Al Wusta desert and strewn field (Figure 4b) with an area of 4 km by 2 km, it is suggested that a large piece of the rock may have broken down into several varyingly sized pieces before landing on the Earth’s surface. The shattering of the rock may have been triggered by the frictional heat in the air, thus causing it to break twice, first in the air followed by the impact on the ground. Table 4. Petrological data of Sayh al Uhaymir (SaU) 005 Martian meteorite and pairings from the Sultanate of Oman. Name Major Phases (write-up in Meteoritical Bulletin) Minor Phases Shock Stage Ref. Remarks SaU 005 ol (Fo64-71), pig (En61-70Wo6-13), mask (An51-65Or0.3-0.9) aug, pho, opa strongly shocked [39] SaU 008 same as above same as above same as above [39] SaU 051 ol (Fo61-68), pig (En60-68Wo7-12), mask (An59-67) not given S5 [36] paired with 005/008 SaU 094 ol (Fo65-69), pig (En60-68Wo7-9), mask (An55-64Or5-9) aug, chr, pyr S5 [36] SaU 060 ol (Fo63.1-70.8), pig (En60-69.6Wo7.1-8.6), mask (An 61.4-68.3Or0.5-1.6) aug (rare) S5 [34] aug = En47Wo35 SaU 090 not given not given not given [34] SaU 150 ol (Fo67-74), pig (En62-69Wo7-11), mask (An 53-66Or0.3-0.8) Ca-poor px S5 [37] a patch of fusion crust SaU 120 not given not given not given [37] paired with all finds SaU 125 not given not given not given [46] paired with all finds SaU 130 not given not given not given [46] paired with all finds SaU 587 ol (Fa34±0.5), pig (Fs25.2±2Wo9.2±1.6), mask (An 60.4-65.9Or0.4-o.6) pho, sul, chr not given [38] shock metamorphism ol = olivine. pig = pigeonite. mask = maskelynite. aug = augite. pho = phosphate. opa = opaques. chr = chromite. pyr = pyrrhotite. px = pyroxene. sul = sulfide. 4. Conclusion Martian meteorites provide an unprecedented means of information about Mars and are rarely found, compared to other types of meteorites. The Sultanate of Oman has contributed 17 approved Martian meteorites to the 137 found globally. Most of them were recovered from the Al Wusta desert in searches during the last15 years. The bulk of the main mass of SaU 005 and its pairings (i.e., 10.9 kg out of total 11.2 kg) recovered from the Sultanate is in possession of anonymous collectors, depriving Oman of its heritage and denying further research opportunities, given its associated scientific value. SaU 005 and its pairings are of the shergottite type of the Shergotty-Nakhla-Chassigny (SNC) meteorites which originate from the Martian mantle. The published oxygen isotope data of bulk and mineral fractions of SaU 008 and Dhofar 019 display a narrow range in δ18O values. These data are indistinguishable in terms of Δ17O, and fall linearly on a Martian fractionation line above the TFL by +0.32‰, suggesting that Mars’ mantle is homogeneous in oxygen isotopes. Petrographic and mineralogical data of SaU 005 plus pairings are identical, suggesting that all the pieces belong to the same meteorite. Up until 2014, eleven pieces of SaU 005 and its pairings have been recovered, and the strewn field has an area of 4 km by 2 km suggesting that the meteorite may have shattered twice, first in the air prior to landing on the Earth due to frictional heating, and secondly by impact with the ground. 5. Recommendations The history of SaU 005 and its pairings demands a local meteorite museum and preliminary testing laboratory at Sultan Qaboos University (SQU) to protect this treasure trove of Omani heritage. 6. Acknowledgements ARSHAD ALI ET AL 38 We thank Beda A. Hofmann, Elias M.S. 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