Direct Detection of Projectile Relics on the Moon
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Handbook of Iron Meteorites, Volume 3
Sierra Blanca - Sierra Gorda 1119 ing that created an incipient recrystallization and a few COLLECTIONS other anomalous features in Sierra Blanca. Washington (17 .3 kg), Ferry Building, San Francisco (about 7 kg), Chicago (550 g), New York (315 g), Ann Arbor (165 g). The original mass evidently weighed at least Sierra Gorda, Antofagasta, Chile 26 kg. 22°54's, 69°21 'w Hexahedrite, H. Single crystal larger than 14 em. Decorated Neu DESCRIPTION mann bands. HV 205± 15. According to Roy S. Clarke (personal communication) Group IIA . 5.48% Ni, 0.5 3% Co, 0.23% P, 61 ppm Ga, 170 ppm Ge, the main mass now weighs 16.3 kg and measures 22 x 15 x 43 ppm Ir. 13 em. A large end piece of 7 kg and several slices have been removed, leaving a cut surface of 17 x 10 em. The mass has HISTORY a relatively smooth domed surface (22 x 15 em) overlying a A mass was found at the coordinates given above, on concave surface with irregular depressions, from a few em the railway between Calama and Antofagasta, close to to 8 em in length. There is a series of what appears to be Sierra Gorda, the location of a silver mine (E.P. Henderson chisel marks around the center of the domed surface over 1939; as quoted by Hey 1966: 448). Henderson (1941a) an area of 6 x 7 em. Other small areas on the edges of the gave slightly different coordinates and an analysis; but since specimen could also be the result of hammering; but the he assumed Sierra Gorda to be just another of the North damage is only superficial, and artificial reheating has not Chilean hexahedrites, no further description was given. -
Sulfide/Silicate Melt Partitioning During Enstatite Chondrite Melting
61st Annual Meteoritical Society Meeting 5255.pdf SULFIDE/SILICATE MELT PARTITIONING DURING ENSTATITE CHONDRITE MELTING. C. Floss1, R. A. Fogel2, G. Crozaz1, M. Weisberg2, and M. Prinz2, 1McDonnell Center for the Space Sciences and Department of Earth and Planetary Sciences, Washington University, St. Louis MO 63130, USA ([email protected]), 2American Museum of Natural History, Department of Earth and Planetary Sciences, New York NY 10024, USA. Introduction: Aubrites are igneous rocks thought (present only in CaS-saturated charges) has a flat REE to have formed from an enstatite chondrite-like pattern with abundances of about 0.5 x CI. precursor [1]. Yet their origin remains poorly Discussion: Oldhamite/glass D values are close to understood, at least partly because of confusion over 1 for most REE, consistent with previous results the role played by sulfides, particularly oldhamite. [4,5,6], and significantly lower than those expected CaS in aubrites contains high rare earth element based on REE abundances in aubritic oldhamite. In (REE) abundances and exhibits a variety of patterns contrast, D values for FeS are surprisingly high (from [2] that reflect, to some extent, those seen in about 0.1 to 1), given the low REE abundances of oldhamite from enstatite chondrites [3]. However, natural troilite. FeS/silicate partition coefficients experimental work suggests that CaS/silicate melt reported by [5] are somewhat lower, but exhibit a REE partition coefficients are too low to account for similar pattern. Alkali loss from the charges, the high abundances observed [4,5] and do not explain resulting in Ca-enriched glass, might provide a partial the variable patterns. -
TUPELO, a NEW EL6 ENSTATITE CHONDRITE. DR Dunlap1
44th Lunar and Planetary Science Conference (2013) 2088.pdf TUPELO, A NEW EL6 ENSTATITE CHONDRITE. D. R. Dunlap1 ([email protected]), M. L. Pewitt1 ([email protected]), H. Y. McSween1, Raymond Doherty2, and L. A. Taylor1, 1Planetary Geoscience Institute, De- partment of Earth and Planetary Sciences, University of Tennessee, Knoxville, TN, 37996, USA, 24441 W Main Street, Tupelo, MS 38801, USA. Introduction: Enstatite chondrites are the rarest phosphides, and metal. Modal analyses of the two and most reduced chondrite clan [1]. E-chondrites are analyzed sections are given in Table 1. The subdivided into two groups, EL and EH, based on kamcite/silicate ratios of both sections are consistent modal iron-metal abundances. E-chondrites are charac- with EL chondrites. terized by the presence of nearly pure enstatite and silicon-bearing metal, with ferroan-alabandite in EL and niningerite in EH. Additionally, elements that are typically lithophilic in most meteorite groups (e.g., Mn, Mg, Ca, Na, K) can behave like chalcophile ele- ments in the E-chondrites due to the extremely reduc- ing conditions, forming a variety of accessory phases. Table 1. Modal analyses of Tupelo after [3]. * include graphite, Metamorphic characteristics used to define petrologic schreibersite, and all other non-sulfide, non-silicate minerals present. types [2] do not apply well to E-chondrites; therefore, **Troilite also includes alabandite and daubreelite. mineralogic types are utilized to specify metamorphic grade [3]. The silicates are nearly FeO-free enstatite (En98) The 280g Tupelo meteorite was found in 2012 by and sodic plagioclase feldspar (Ab77.7Or4.8). This feld- Maura O’Connell and Raymond Doherty, in a field in spar composition is consistent with composition re- Mississippi while looking for Indian artifacts. -
Fe,Mg)S, the IRON-DOMINANT ANALOGUE of NININGERITE
1687 The Canadian Mineralogist Vol. 40, pp. 1687-1692 (2002) THE NEW MINERAL SPECIES KEILITE, (Fe,Mg)S, THE IRON-DOMINANT ANALOGUE OF NININGERITE MASAAKI SHIMIZU§ Department of Earth Sciences, Faculty of Science, Toyama University, 3190 Gofuku, Toyama 930-8555, Japan § HIDETO YOSHIDA Department of Earth and Planetary Science, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan § JOSEPH A. MANDARINO 94 Moore Avenue, Toronto, Ontario M4T 1V3, and Earth Sciences Division, Royal Ontario Museum, 100 Queens’s Park, Toronto, Ontario M5S 2C6, Canada ABSTRACT Keilite, (Fe,Mg)S, is a new mineral species that occurs in several meteorites. The original description of niningerite by Keil & Snetsinger (1967) gave chemical analytical data for “niningerite” in six enstatite chondrites. In three of those six meteorites, namely Abee and Adhi-Kot type EH4 and Saint-Sauveur type EH5, the atomic ratio Fe:Mg has Fe > Mg. Thus this mineral actually represents the iron-dominant analogue of niningerite. By analogy with synthetic MgS and niningerite, keilite is cubic, with space group Fm3m, a 5.20 Å, V 140.6 Å3, Z = 4. Keilite and niningerite occur as grains up to several hundred m across. Because of the small grain-size, most of the usual physical properties could not be determined. Keilite is metallic and opaque; in reflected light, it is isotropic and gray. Point-count analyses of samples of the three meteorites by Keil (1968) gave the following amounts of keilite (in vol.%): Abee 11.2, Adhi-Kot 0.95 and Saint-Sauveur 3.4. -
Handbook of Iron Meteorites, Volume 2 (Canyon Diablo, Part 2)
Canyon Diablo 395 The primary structure is as before. However, the kamacite has been briefly reheated above 600° C and has recrystallized throughout the sample. The new grains are unequilibrated, serrated and have hardnesses of 145-210. The previous Neumann bands are still plainly visible , and so are the old subboundaries because the original precipitates delineate their locations. The schreibersite and cohenite crystals are still monocrystalline, and there are no reaction rims around them. The troilite is micromelted , usually to a somewhat larger extent than is present in I-III. Severe shear zones, 100-200 J1 wide , cross the entire specimens. They are wavy, fan out, coalesce again , and may displace taenite, plessite and minerals several millimeters. The present exterior surfaces of the slugs and wedge-shaped masses have no doubt been produced in a similar fashion by shear-rupture and have later become corroded. Figure 469. Canyon Diablo (Copenhagen no. 18463). Shock The taenite rims and lamellae are dirty-brownish, with annealed stage VI . Typical matte structure, with some co henite crystals to the right. Etched. Scale bar 2 mm. low hardnesses, 160-200, due to annealing. In crossed Nicols the taenite displays an unusual sheen from many small crystals, each 5-10 J1 across. This kind of material is believed to represent shock annealed fragments of the impacting main body. Since the fragments have not had a very long flight through the atmosphere, well developed fusion crusts and heat-affected rim zones are not expected to be present. The energy responsible for bulk reheating of the small masses to about 600° C is believed to have come from the conversion of kinetic to heat energy during the impact and fragmentation. -
Magmatic Sulfides in the Porphyritic Chondrules of EH Enstatite Chondrites
Published in Geochimica et Cosmochimica Acta, Accepted September 2016. http://dx.doi.org/10.1016/j.gca.2016.09.010 Magmatic sulfides in the porphyritic chondrules of EH enstatite chondrites. Laurette Piani1,2*, Yves Marrocchi2, Guy Libourel3 and Laurent Tissandier2 1 Department of Natural History Sciences, Faculty of Science, Hokkaido University, Sapporo, 060-0810, Japan 2 CRPG, UMR 7358, CNRS - Université de Lorraine, 54500 Vandoeuvre-lès-Nancy, France 3 Laboratoire Lagrange, UMR7293, Université de la Côte d’Azur, CNRS, Observatoire de la Côte d’Azur,F-06304 Nice Cedex 4, France *Corresponding author: Laurette Piani ([email protected]) Abstract The nature and distribution of sulfides within 17 porphyritic chondrules of the Sahara 97096 EH3 enstatite chondrite have been studied by backscattered electron microscopy and electron microprobe in order to investigate the role of gas-melt interactions in the chondrule sulfide formation. Troilite (FeS) is systematically present and is the most abundant sulfide within the EH3 chondrite chondrules. It is found either poikilitically enclosed in low-Ca pyroxenes or scattered within the glassy mesostasis. Oldhamite (CaS) and niningerite [(Mg,Fe,Mn)S] are present in ! 60 % of the chondrules studied. While oldhamite is preferentially present in the mesostasis, niningerite associated with silica is generally observed in contact with troilite and low-Ca pyroxene. The Sahara 97096 chondrule mesostases contain high abundances of alkali and volatile elements (average Na2O = 8.7 wt.%, K2O = 0.8 wt.%, Cl = 7000 ppm and S = 3700 ppm) as well as silica (average SiO2 = 63.1 wt.%). Our data suggest that most of the sulfides found in EH3 chondrite chondrules are magmatic minerals that formed after the dissolution of S from a volatile-rich gaseous environment into the molten chondrules. -
The Moon After Apollo
ICARUS 25, 495-537 (1975) The Moon after Apollo PAROUK EL-BAZ National Air and Space Museum, Smithsonian Institution, Washington, D.G- 20560 Received September 17, 1974 The Apollo missions have gradually increased our knowledge of the Moon's chemistry, age, and mode of formation of its surface features and materials. Apollo 11 and 12 landings proved that mare materials are volcanic rocks that were derived from deep-seated basaltic melts about 3.7 and 3.2 billion years ago, respec- tively. Later missions provided additional information on lunar mare basalts as well as the older, anorthositic, highland rocks. Data on the chemical make-up of returned samples were extended to larger areas of the Moon by orbiting geo- chemical experiments. These have also mapped inhomogeneities in lunar surface chemistry, including radioactive anomalies on both the near and far sides. Lunar samples and photographs indicate that the moon is a well-preserved museum of ancient impact scars. The crust of the Moon, which was formed about 4.6 billion years ago, was subjected to intensive metamorphism by large impacts. Although bombardment continues to the present day, the rate and size of impact- ing bodies were much greater in the first 0.7 billion years of the Moon's history. The last of the large, circular, multiringed basins occurred about 3.9 billion years ago. These basins, many of which show positive gravity anomalies (mascons), were flooded by volcanic basalts during a period of at least 600 million years. In addition to filling the circular basins, more so on the near side than on the far side, the basalts also covered lowlands and circum-basin troughs. -
Radar-Enabled Recovery of the Sutter's Mill Meteorite, A
RESEARCH ARTICLES the area (2). One meteorite fell at Sutter’sMill (SM), the gold discovery site that initiated the California Gold Rush. Two months after the fall, Radar-Enabled Recovery of the Sutter’s SM find numbers were assigned to the 77 me- teorites listed in table S3 (3), with a total mass of 943 g. The biggest meteorite is 205 g. Mill Meteorite, a Carbonaceous This is a tiny fraction of the pre-atmospheric mass, based on the kinetic energy derived from Chondrite Regolith Breccia infrasound records. Eyewitnesses reported hearing aloudboomfollowedbyadeeprumble.Infra- Peter Jenniskens,1,2* Marc D. Fries,3 Qing-Zhu Yin,4 Michael Zolensky,5 Alexander N. Krot,6 sound signals (table S2A) at stations I57US and 2 2 7 8 8,9 Scott A. Sandford, Derek Sears, Robert Beauford, Denton S. Ebel, Jon M. Friedrich, I56US of the International Monitoring System 6 4 4 10 Kazuhide Nagashima, Josh Wimpenny, Akane Yamakawa, Kunihiko Nishiizumi, (4), located ~770 and ~1080 km from the source, 11 12 10 13 Yasunori Hamajima, Marc W. Caffee, Kees C. Welten, Matthias Laubenstein, are consistent with stratospherically ducted ar- 14,15 14 14,15 16 Andrew M. Davis, Steven B. Simon, Philipp R. Heck, Edward D. Young, rivals (5). The combined average periods of all 17 18 18 19 20 Issaku E. Kohl, Mark H. Thiemens, Morgan H. Nunn, Takashi Mikouchi, Kenji Hagiya, phase-aligned stacked waveforms at each station 21 22 22 22 23 Kazumasa Ohsumi, Thomas A. Cahill, Jonathan A. Lawton, David Barnes, Andrew Steele, of 7.6 s correspond to a mean source energy of 24 4 24 2 25 Pierre Rochette, Kenneth L. -
Geological Survey Canada
70-66 GEOLOGICAL PAPER 70-66 ., SURVEY OF CANADA DEPARTMENT OF ENERGY, MINES AND RESOURCES REVISED CATALOGUE OF THE NATIONAL METEORITE COLLECTION OF CANADA LISTING ACQUISITIONS TO AUGUST 31, 1970 J. A. V. Douglas 1971 Price, 75 cents GEOLOGICAL SURVEY OF CANADA CANADA PAPER 70-66 REVISED CATALOGUE OF THE NATIONAL METEORITE COLLECTION OF CANADA LISTING ACQUISITIONS TO AUGUST 31, 1970 J. A. V. Douglas DEPARTMENT OF ENERGY, MINES AND RESOURCES @)Crown Copyrights reserved Available by mail from Information Canada, Ottawa from the Geological Survey of Canada 601 Booth St., Ottawa and Information Canada bookshops in HALIFAX - 1735 Barrington Street MONTREAL - 1182 St. Catherine Street West OTTAWA - 171 Slater Street TORONTO - 221 Yonge Street WINNIPEG - 499 Portage Avenue VANCOUVER - 657 Granville Street or through your bookseller Price: 75 cents Catalogue No. M44-70-66 Price subject to change without notice Information Canada Ottawa 1971 ABSTRACT A catalogue of the National Meteorite Collection of Canada, published in 1963 listed 242 different meteorite specimens. Since then specimens from 50 a dditional meteorites have been added to the collection and several more specimens have been added to the tektite collection. This report describes all specimens in the collection. REVISED CATALOGUE OF THE NATIONAL METEORITE COLLECTION OF CANADA LISTING ACQUISITIONS TO AUGUST 31, 1970 INTRODUCTION At the beginning of the nineteenth century meteorites were recog nized as unique objects worth preserving in collections. Increasingly they have become such valuable objects for investigation in many fields of scienti fic research that a strong international interest in their conservation and pre servation has developed (c. f. -
Sulfides in Enstate Chondrites
Sulfides in Enstatite Chondrites: Indicators of Impact History Kristyn Hill1,2, Emma Bullock2, Cari Corrigan2, and Timothy McCoy2 1Lock Haven University of Pennsylvania, Lock Haven, PA 17745, USA 2National Museum of Natural History, Department of Mineral Sciences, Washington D.C. 20013, USA Introductton Results Discussion Enstatite chondrites are a class of meteorites. They are Determining the history of the parent body of a referred to as chondrites because of the spherical Impact Melt, Slowly Cooled chondritic meteorite often includes distinguishing whether chondrules found in the matrix of the meteorites. Enstatite aa bb cc d d or not the meteorite was impact melted, and the cooling chondrites are the most highly reduced meteorites and rate. contain iron-nickel metal and sulfide bearing minerals. The Impact melts are distinguishable by the texture of the matrix is made up of silicates, enstatite in particular. There metal and sulfide assemblages. A meteorite that was are usually no oxides found, which supports the idea that impact melted will contain a texture of euhedral to these formed in very oxygen poor environments. The subhedral silicates, like enstatite, protruding into the metal enstatite chondrites in this study are type 3, meaning they or sulfides (figure 2). Some textures will look shattered are unmetamorphosed and not affected by fluids. (figure 2b). Meteorites that contain the mineral keilite are Studying enstatite chondrites will help us determine the PCA 91125 ALHA 77156 PCA 91444 PCA 91085 also an indicator of impact melts (figure 3). Keilite only evolution of their parent bodies which formed at the occurs in enstatite chondrite impact-melt rocks that cooled beginning of our solar system. -
Thermal History of the Enstatite Chondrites from Silica Polymorphs
Meteoritics & Planetary Science 40, Nr 6, 855–868 (2005) Abstract available online at http://meteoritics.org Thermal history of the enstatite chondrites from silica polymorphs M. KIMURA1*, M. K. WEISBERG2, Y. LIN3, A. SUZUKI4, E. OHTANI4, and R. OKAZAKI5 1Faculty of Science, Ibaraki University, Mito 310-8512, Japan 2Department of Physical Sciences, Kingsborough College of the City University of New York, Brooklyn, New York 11235, and Department of Earth and Planetary Sciences, American Museum of Natural History, New York, New York 10024, USA 3State Key Laboratory of Lithosphere Tectonic Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China 4Institute of Mineralogy, Petrology, and Economic Geology, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan 5Department of Earth and Planetary Sciences, Faculty of Sciences, Kyushu University, Fukuoka 812-8581, Japan *Corresponding author. E-mail: [email protected] (Received 18 January 2005; revision accepted 14 April 2005) Abstract–Here we report the results of our petrologic and mineralogical study of enstatite (E) chondrites in order to explore their thermal histories. We studied silica phases in 20 E chondrites by laser micro Raman spectroscopy to determine the silica polymorphs they contain. Silica phases are commonly present in E chondrites and their polymorphs reflect the physical conditions of formation. The samples studied here include EH3–5, EL3–6, E chondrite melt rocks, and an anomalous E chondrite. We identified quartz, tridymite, cristobalite, and silica glass in the samples studied. EH4– 5 and EH melt rocks are divided into high and low temperature classes based on niningerite- alabandite solid solutions. -
Introduction: Oldhamite (Cas) and Niningerite (Mgs), Both of Which Are Highly Reduced Phases in EH Chondrites, Have Been Propose
41st Lunar and Planetary Science Conference (2010) 1855.pdf SILICA-RICH CHONDRULES IN ALH 84170 AND SAHARA 97072 EH3 METEORITES: EVIDENCE FOR SULFIDATION OF SILICATES. S. W. Lehner1 and P. R. Buseck1, 1School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287, ([email protected], [email protected]). Introduction: Oldhamite (CaS) and niningerite Chondrules range from being dominated by silica (Fig. (MgS), both of which are highly reduced phases in EH 1) to consisting of enstatite with enclosed silica, troilite, chondrites, have been proposed to have condensed from and niningerite. Other chondrule regions contain be- a fractionated solar gas with a C/O ratio ~1 [1]. How- tween 70 and 95 wt % SiO2 but also contain up to 5 wt ever, this model has been questioned because it does not % S and significant Ca or Na. These areas yield low to- explain the limited abundance of graphite in E3 chon- tals in microprobe analyses, are relatively dark, and ap- drites; the need to preserve the sulfides below ~1000 K pear fibrous in electron backscattered images, suggest- where, according to the C/O ~1 model, they become un- ing they are either porous, have high volatile content, or stable [2]; and the high concentrations of volatile ele- unidentified light elements such as C. Most chondrules ments in oldhamite. An alternative mechanism for the contain Al-rich phases, identified as plagioclase, augite, formation of ECs from a nebula of solar composition is or both with Raman spectroscopy. All chondrules con- provided by the condensation with partial isolation tain enstatite, most of which is clinoenstatite (avg.