DOCSLIB.ORG

Implications of a Titanium-Rich Glass Clod at Oceanus Procellarum

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Implications of a Titanium-Rich Glass Clod at Oceanus Procellarum A merican M ineralog is t, Volwne 6 3, pages 92 4 -9 29, I 97 8 Implicationsof a titanium-richglass clod at OceanusProcellarum Unsule B. MenvtN H aruard- S miths onian C ente r fo r A strophysi cs Cambridge,M assachusetts 02I 38 lNp Devto Wnlrrn Departmentof Geology,Haruard Uniuersity Camb ridge, M assachuset ts 02 I 38 Abstract A friable clod consistingof spherulesand conchoidalfragments of red-blackglass with an exceptionallytitanium-rich composition (-16 percentTiOr) was discoveredin the 2-4 mm fractionof Apollo l2 sample12033. Despite a diligentsearch of the remainingApollo l2 soils, no similarfragment has beenfound in the samplesfrom that or any other lunar mission.By analogywith the glassspherule clods collectedat the Apollo 15 and Apollo 17 sites,this uniqueclod of glassmay representa lunar magmaof which no crystallineequivalent has yet beenfound. The probabilityis smallthat magmaswith the compositionof the red-blackglass could be parentalto high-K titaniferousApollo I I basaltby low-pressurefractional crystallization. Red-blackglass composition cannot be parentalto any other lunar basalttypes. If red-black glassis a magmatype, and not an accidentallyremelted cumulate, its existencerequires that gross heterogeneityof TiO, characterizelunar magmasource regions and/or that simple modelsof magmagenesis cannot produce this type. Occurrence suggestan affinity with mare basaltsrather than no- rites. A friable spheruleaggregate, which looked like a When the clod was discoveredin the summerof dollopof blackcaviar (Fig. I ), wasrecognized as an 197l,it wasimmediately mounted in epoxyand cut exceptionalparticle of lunar soil during a macro- into a thin section.As no more of the clod remains, scopicsurvey of Apollo 12 sample 12033,66.The the opportunitywas thus lost to treat this 2-mm samplerepresented a layerof light gray soil that was particleas a consortiumrock (an approachthat was exposedat a depthof a few centimetersin the wallsof developedlater) in order to determineits age and a trench the astronautsdug through the rim of Head trace elementcontent and to analysethe spherule Crater.The light color of the soil signaledan abun- surfacesfor micromoundsof condensedvolatiles, as danceof small ropy fragmentsof KnErp-richglass wasdone subsequently on theApollo l5 greensphe- coatedwith gray-whitedust. The ropy glasseshave rulesand the Apollo 17orange and black spherules beeninterpreted as either ray materialfrom the crater (for reviewsee Butler and Meyer, 1976). Copernicus(Meyer et al., l97l) or as shock-melted A singlesoil particle,regardless of how exotic its ejecta from a more local impact crater that pene- composition,hardly seemsadequate for formulating trated thin mare flows and excavatednoritic materi- a petrogenetichypothesis. In order to find additional als (Quaide et al., l97l). Although the dark clod, examplesto be usedfor surficialanalyses and other which differedstrikingly in textureand composition studies,an arrangementwas madeby U. B. Marvin from all other particlesin the Apollo 12 soils,oc- in 1977to examineand catalogue the Apollo l2 soils curredin a sampleconsisting of 40 percentropy glass in storagein the CuratorialFacility at Houston(cata- fragments,no geneticassociation between these par- logue in preparation).A diligent searchof all the ticle types need be assumed.On the contrary, high fractions coarserthan 0.55 mm failed to locate a valuesof titanium and chromiumin the dark glasses single spheruleor spheruleaggregate of red-black 0003-004x/7 8/09 I 0-0924$02.00 924 MARVIN AND WALKER' TITANIUM-RICH GLASS CLOD 92s glass.Inasmuch as no similarclod has been found in -'r'i'ti anyother lunar soil, the original clod remains unique. Texture In thin sectionthe clod is nearlyopaque in trans- mittedlight, but the extraillumination provided by a substagecondenser shows that the main constituent is a very dark red-blackglass. A single50-pm frag- ment of clinopyroxeneis locatednear the centerof the section,but most if not all of the many other small transparentphases are crystallitesof olivine and pyroxene.Reflected light (Fig. 2a) revealsthat the clodis a porousaggregate of spherules(5- I 30pm dia.), conchoidalspherule fragments, and irregular chunks of glass.Some of theseglass chunks and partially devitrifiedfragments of spheruleshave been compressedtogether into new aggregates,but clasts incorporatinglithologies other than red-blackglass and its partial devitrificationproducts were not ob- served.About 35 percentof the glassyparticles are brownishin colorand contain well-developed crystal- lites of ilmenite,olivine, and/or pyroxenewith a maximumsize of 2.5x 1.4pm (Figs.2b,2c,2d). The remaining65 percentof the spherulesand fragments are dark red and cloudy,with opaquesubmicron Fig 2. Views in reflected light of the polished thin section ofthe crystallitesdistributed uniformly or alignedin feath- glassy clod. (a) View of the entire particle showing the distribution erypatterns in theglass. The presence of theseminute of spherules in the porous matrix of conchoidal glass fragments. pre-existing portion crystallitesgives the dark glassesan exceptionally The dark diagonal streaks are fractures. (b) A of the section illustrating the contrast between the highly reflective bright reflectivity which makes the mafic silicates spherulesand fragments containing minute, uniformly distributed look dull grayin comparison.This is theopposite of opaque crystallites and the fragments of darker glass with the usual reflectivity contrast betweenglasses and prominent crystallites (c) Two particles with crystallites in maficsilicates. different stages of growth. The particle at the upper left has a delicate dendritic pattern of ilmenite. The one at lower left includes Composition ilmenite crystallites plus one elongated olivine crystallite which occupies the band between the lobe at the left and the larger Electron microprobe analysesof the homoge- portion at the right. The remaining matrix material is brownish neous-appearingdark spherulesand fragmentsshow glass that partially covers the olivine, making it indistinguishable in this photograph. (d) A "homogeneous" spherule and an irregular mass of glass with the more uniform variety grading into the more coarsely crystalline type. thenarrow compositional range listed in TableI and plotted in Figures3 and 4. The red-blackglass is olivine-normativeand containsabout 3l weightper- cent of normativeilmenite. The growth of olivine, ilmenite,and a few clinopyroxenecrystallites in the red-blackglass produces a lighter-colored,quartz- normative, pyroxene-plagioclase-richresidual glass (Table l). Most attemptsto analyzethe crystallites failed to yield mineralcompositions unmixed with glass.However, two good crystalliteanalyses are of olivine(Forr) containing 0.3 percent Cr. Thisvalue of Fig. l The 2-mm clod of spherulesand fragments of red-black chromiumin a lunarrock suggestsa genetic relation- glass from Apollo 12 sample 12033,66. shio with mare basaltsrather than with noritesor 926 MARVIN AND WALKER: TITANIUM.RICH GLASS CLOD Table l. Electronmicroprobe analyses of the glassclod Glassspherules and clods A. The averageand range of valuesin 8 particlesof red-black Impactand volcanism are both glass-forming proc- glass "homogeneous" esses,and both aregenerally believed to havecontrib- B. Bulk compositionof the clod,derived from theaverageof8 100 pm broad-beamanalyses recalculated to 100percent uted glassyparticles to the lunar regolith.To distin- C, The compositionof I particle of brown quartz-normative, guish impact from volcanicglass is sometimesa residualglass containing crystallites of olivineand ilmenite relatively straightforward exercise:impact glasses may havethe compositionof non-igneoustarget ma- terials,whereas volcanic glasses should duplicate or Avg. Range showa closegenetic relationship to the compositions of volcaniclavas. It becomesmore dimcult to distin- - ?? nt S102 33.44 31.83 35.14 42.8r guish betweenimpact and volcanic origins when T102 ro.J/ ro.uz - ro./o r). oo 10.54 glassyparticles are the product of impacts into ig- 41203 4.60 3.90 - 5.41 6.2r 5.15 neousrocks or remeltedbreccias with largepropor- Ct20g 0.84 0.71 - 0.98 1.00 0,22 tions of igneousclasts. Particles of eitherimpact or Fe0 23.87 23.42- 24.43 zJ.04 20.88 glass in association ltn0 0.30 0.24 - 0.36 0.30 0.30 volcanic would logicallyoccur Mgo 13.00 12.04 - 13.87 1a <1 8.15 with unmeltedfragments of equivalentcomposition. Ca0 6.27 5.14 - 6.90 6.69 LO.74 Thus many lunar glassesare not easilyclassified. Na20 0.05 0.00 - 0.13 0.15 0.30 Spherulesof clearglass in a wide spectrumof col- Kzo o,r2 0.03 - 0,42 0.40 o.7r ors are ubiquitousin the lunar soils,and thoseindi- N10 0.02 0.00 - 0.06 o.o2 0.03 viduals that mimic the compositionof individual Pzos n.d. 0.20 0.17 mineralsor of bulk soilsare readily ascribedto im- qn^ - v-5 0.08 0.01 0,16 0.r2 0.09 pact. If impact was the processresponsible for pro- spheruledeposits, the highland AOEAI 98.96 100.00 100,09 ducing aggregated soils should include discretelayers or lensesrich in anorthositicgabbros (Marvin et al., l97l). Oneanal- ysis yielded a normative compositionof 94 percent -A PSEUDOTERNARY I II HIGH-K clinopyroxene(EnrrFsnoWols). The singlepyroxene 2'A il,t7LoW-K LIQUIDUS S.ORANGESOIL fragment not occurring as a crystalliteis more Ca- PROJECTION 4'At2 ILM rich (EnarFsroWor,). FROM 5=Lt6 6=At2 PtC-PtG In an attemptto determinethe bulk compositionof CnAL2St2Os 7-A t5 the clod, a numberof 100-pmbroad-beam analyses S.GREENGLASS, L24,VLT were made at random on the section.The
Load more

Recommended publications
  • A Zircon U-Pb Study of the Evolution of Lunar KREEP
    A zircon U-Pb study of the evolution of lunar KREEP By A.A. Nemchin, R.T. Pidgeon, M.J. Whitehouse, J.P. Vaughan and C. Meyer Abstract SIMS U-Pb analyses show that zircons from breccias from Apollo 14 and Apollo 17 have essentially identical age distributions in the range 4350 to 4200 Ma but, whereas Apollo 14 zircons additionally show ages from 4200 to 3900 Ma, the Apollo 17 samples have no zircons with ages <4200 Ma. The zircon results also show an uneven distribution with distinct peaks of magmatic activity. In explaining these observations we propose that periodic episodes of KREEP magmatism were generated from a primary reservoir of KREEP magma, which contracted over time towards the centre of Procellarum KREEP terrane. Introduction One of the most enigmatic features of the geology of the Moon is the presence of high concentrations of large ion lithophile elements in clasts from breccias from non mare regions. This material, referred to as KREEP (1) from its high levels of K, REE and P, also contains relatively high concentrations of other incompatible elements including Th, U and Zr. Fragments of rocks with KREEP trace element signatures have been identified in samples from all Apollo landing sites (2). The presence of phosphate minerals, such as apatite and merrillite (3); zirconium minerals, such as zircon (4), zirconolite (5) and badelleyite (6), and rare earth minerals such as yttrobetafite (7), are direct expressions of the presence of KREEP. Dickinson and Hess (8) concluded that about 9000 ppm of Zr in basaltic melt is required to saturate it with zircon at about 1100oC (the saturation concentration increases exponentially with increasing temperature).
    [Show full text]
  • Read Book ^ Titans: Atlas, Titan, Rhea, Helios, Eos, Prometheus, Hecate
    [PDF] Titans: Atlas, Titan, Rhea, Helios, Eos, Prometheus, Hecate, Oceanus, Metis, Mnemosyne, Titanomachy, Selene, Themis, Tethys,... Titans: Atlas, Titan, Rhea, Helios, Eos, Prometheus, Hecate, Oceanus, Metis, Mnemosyne, Titanomachy, Selene, Themis, Tethys, Theia, Iapetus, Coeus, Crius, Asteria, Epimetheus, Hyperion, Astraeus, Cron Book Review A superior quality pdf along with the font used was intriguing to read through. It can be rally exciting throgh reading through time period. You may like how the blogger create this book. (Dr. Rylee Berg e) TITA NS: ATLA S, TITA N, RHEA , HELIOS, EOS, PROMETHEUS, HECATE, OCEA NUS, METIS, MNEMOSYNE, TITA NOMA CHY, SELENE, THEMIS, TETHYS, THEIA , IA PETUS, COEUS, CRIUS, A STERIA , EPIMETHEUS, HYPERION, A STRA EUS, CRON - To download Titans: A tlas, Titan, Rhea, Helios, Eos, Prometheus, Hecate, Oceanus, Metis, Mnemosyne, Titanomachy, Selene, Themis, Tethys, Theia, Iapetus, Coeus, Crius, A steria, Epimetheus, Hyperion, A straeus, Cron PDF, you should access the web link under and save the ebook or have accessibility to other information which are have conjunction with Titans: Atlas, Titan, Rhea, Helios, Eos, Prometheus, Hecate, Oceanus, Metis, Mnemosyne, Titanomachy, Selene, Themis, Tethys, Theia, Iapetus, Coeus, Crius, Asteria, Epimetheus, Hyperion, Astraeus, Cron book. » Download Titans: A tlas, Titan, Rhea, Helios, Eos, Prometheus, Hecate, Oceanus, Metis, Mnemosyne, Titanomachy, Selene, Themis, Tethys, Theia, Iapetus, Coeus, Crius, A steria, Epimetheus, Hyperion, A straeus, Cron PDF « Our solutions was introduced with a want to serve as a total on the internet electronic digital catalogue that provides use of multitude of PDF file book assortment. You could find many kinds of e-publication and also other literatures from your paperwork database.
    [Show full text]
  • STONEFLY NAMES from CLASSICAL TIMES W. E. Ricker
    ZOBODAT - www.zobodat.at Zoologisch-Botanische Datenbank/Zoological-Botanical Database Digitale Literatur/Digital Literature Zeitschrift/Journal: Perla Jahr/Year: 1996 Band/Volume: 14 Autor(en)/Author(s): Ricker William E. Artikel/Article: Stonefly names from classical times 37-43 STONEFLY NAMES FROM CLASSICAL TIMES W. E. Ricker Recently I amused myself by checking the stonefly names that seem to be based on the names of real or mythological persons or localities of ancient Greece and Rome. I had copies of Bulfinch’s "Age of Fable," Graves; "Greek Myths," and an "Atlas of the Ancient World," all of which have excellent indexes; also Brown’s "Composition of Scientific Words," And I have had assistance from several colleagues. It turned out that among the stonefly names in lilies’ 1966 Katalog there are not very many that appear to be classical, although I may have failed to recognize a few. There were only 25 in all, and to get even that many I had to fudge a bit. Eleven of the names had been proposed by Edward Newman, an English student of neuropteroids who published around 1840. What follows is a list of these names and associated events or legends, giving them an entomological slant whenever possible. Greek names are given in the latinized form used by Graves, for example Lycus rather than Lykos. I have not listed descriptive words like Phasganophora (sword-bearer) unless they are also proper names. Also omitted are geographical names, no matter how ancient, if they are easily recognizable today — for example caucasica or helenica. alexanderi Hanson 1941, Leuctra.
    [Show full text]
  • GRAIL-Identified Gravity Anomalies In
    Solar System Exploration Division, GSFC Code 690 GRAIL-identified gravity anomalies in Oceanus Procellarum: Insight into subsurface impact and volcanic/magmatic structures on the Moon Ariel N. Deutsch1, Gregory A. Neumann2, James W. Head1 1Department of Earth, Environmental and Planetary Sciences, Brown University, 2NASA Goddard Space Flight Center Introduction: Lunar gravity anomalies. Positive Bouguer gravity anomalies. • Four distinctive positive Bouguer gravity anomalies are • Previous work has suggested that these four positive gravity anomalies may be due to: -Subsurface volcanic sills [2]. • New, higher-resolution GRAIL data [3] allow for the re- analysis of these anomalies. • Understanding the subsurface density structures that contribute to these anomalies is important in order to discuss regional impact and volcanic histories, and the evolution of the lunar crust in Oceanus Procellarum. Objectives. 1. Constrain subsurface structures that contribute to the . four positive Bouguer gravity anomalies. 2. Discuss the hidden impact and volcanic histories of . the Moon. Methods. Results: Filled and buried impact craters. RESULTS: MANTLE UPWELLING • Six geologic end-member scenarios are explored to 20 200 1. Filled and Buried Impact 2. Southern Aristarchus Plateau analyze the four observed gravitational anomalies. 15 Model 3 10 GRAIL 100 • Impact crater parameters [e.g., 4] are estimated to C Gravity 5 B from uplift Gravity from A 0 0 km -3 km km ρ = 3150 kg m -5 mGal mGal • Analyses of the generation, ascent, and eruption of -3 mGal ρ = 2800 kg m crater -10 Surface topography -100 -3 of subsurface magmatic structures and also the . -15 ∆ρ = 600 kg m Highland crust -20 -200 Mantle interpretation of surface volcanic features.
    [Show full text]
  • Water on the Moon, III. Volatiles & Activity
    Water on The Moon, III. Volatiles & Activity Arlin Crotts (Columbia University) For centuries some scientists have argued that there is activity on the Moon (or water, as recounted in Parts I & II), while others have thought the Moon is simply a dead, inactive world. [1] The question comes in several forms: is there a detectable atmosphere? Does the surface of the Moon change? What causes interior seismic activity? From a more modern viewpoint, we now know that as much carbon monoxide as water was excavated during the LCROSS impact, as detailed in Part I, and a comparable amount of other volatiles were found. At one time the Moon outgassed prodigious amounts of water and hydrogen in volcanic fire fountains, but released similar amounts of volatile sulfur (or SO2), and presumably large amounts of carbon dioxide or monoxide, if theory is to be believed. So water on the Moon is associated with other gases. Astronomers have agreed for centuries that there is no firm evidence for “weather” on the Moon visible from Earth, and little evidence of thick atmosphere. [2] How would one detect the Moon’s atmosphere from Earth? An obvious means is atmospheric refraction. As you watch the Sun set, its image is displaced by Earth’s atmospheric refraction at the horizon from the position it would have if there were no atmosphere, by roughly 0.6 degree (a bit more than the Sun’s angular diameter). On the Moon, any atmosphere would cause an analogous effect for a star passing behind the Moon during an occultation (multiplied by two since the light travels both into and out of the lunar atmosphere).
    [Show full text]
  • Lunar and Planetary Science XXXII (2001) 1815.Pdf
    Lunar and Planetary Science XXXII (2001) 1815.pdf NEW AGE DETERMINATIONS OF LUNAR MARE BASALTS IN MARE COGNITUM, MARE NUBIUM, OCEANUS PROCELLARUM, AND OTHER NEARSIDE MARE H. Hiesinger1, J. W. Head III1, U. Wolf2, G. Neukum2 1 Department of Geological Sciences, Brown University, Providence, RI 02912, [email protected] 2 DLR-Inst. of Planetary Exploration, Rutherfordstr. 2, 12489 Berlin/Germany Introduction see a second small peak in volcanic activity at ~2-2.2 Lunar mare basalts cover about 17% of the lunar b.y. surface [1]. A significant portion of lunar mare basalts are exposed within Oceanus Procellarum for which Oceanus Procellarum, Mare Cognitum, Mare Nubium absolute radiometric age data are still lacking. Here we (Binned Ages of Mare Basalts) present age data that are based on remote sensing 20 techniques, that is, crater counts. We performed new crater size-frequency distribution measurements for spectrally homogeneous basalt units in Mare Cogni- 15 tum, Mare Nubium, and Oceanus Procellarum. The investigated area was previously mapped by Whitford- Stark and Head [2] who, based on morphology and 10 spectral characteristics, defined 21 distinctive basalt Frequency types in this part of the lunar nearside. Based on a high-resolution Clementine color ratio composite (e.g., 5 750-400/750+400 ratio as red, 750/990 ratio as green, and 400/750 ratio as blue), we remapped the distribu- 0 tion of distinctive basalts and found that their map well 1.1 1.5 2 2.5 3 3.5 4 discriminates the major basalt types. However, based Age [b.y.; bins of 100 m.y.] on the new high-resolution color data several of their units can be further subdivided into spectrally different Fig.
    [Show full text]
  • High Permittivity Regions in Oceanus Procelluram and Mare Imbrium Found by Selene (Kaguya)
    46th Lunar and Planetary Science Conference (2015) 1316.pdf HIGH PERMITTIVITY REGIONS IN OCEANUS PROCELLURAM AND MARE IMBRIUM FOUND BY SELENE (KAGUYA). A. Kumamoto1, K. Ishiyama1, S. Oshigami2, J. Haruyama3, and Y. Goto4, 1Tohoku Univer- sity (Aoba, Aramaki, Aoba, Sendai 980-8578, Japan. E-mail: [email protected]), 2National Astro- nomical Observatory of Japan, 3Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 4Kanazawa University. Introduction: The determination of the effective surface echo consist of various components such as off- permittivity of the lunar surface material is useful for nadir surface echoes, volume scatters from the subsur- discussion of their composition and porosity. Assuming face layers, and echoes from the subsurface reflectors. the Maxwell-Garnett mixing relation and parameters In this study, we assumed that most of them was off- based on Apollo samples [1], the bulk density bulk of nadir surface echoes. The median of off-nadir echo the lunar surface materials can be derived from their intensities were derived in 360 x 180 areas of 1 (lon- effective permittivity r by using the following equa- gitude) x 1 (latitude). tion: In addition, we have derived the global distribution 1 1 of the surface roughness parameters. The RMS height r 0.217 . (1) 3 , or Allan deviation of the surface height, can be ob- bulk g/m r 2 Bulk density of the lunar surface material depends on tained by 2 2 the abundances of voids and heavy components such as x zx x zx , (2) ilmenite. The dataset obtained by Lunar Radar Sounder where z(x) is height of the surface derived from the (LRS) onboard SELENE (Kaguya) [2] enables us to SELENE TC/DTM, x is baseline length, and <> de- perform global high-resolution mapping of the lunar notes the average.
    [Show full text]
  • The Stratigraphy of Mare Basalts in Oceanus Procellarum: Initial Results from New Crater Size-Frequency Distribution Measurements
    ICEUM4, 10-15 July 2000, ESTEC, Noordwijk, The Netherlands The Stratigraphy of Mare Basalts in Oceanus Procellarum: Initial Results from New Crater Size-Frequency Distribution Measurements H. Hiesinger, J.W. Head III (Dept. of Geological Sciences, Brown University, USA); Wolf, U., Neukum, G. (DLR- Institute of Space Sensor Technology and Planetary Exploration, Germany) The stratigraphy of basalts in Oceanus Procellarum was previously investigated by Whitford-Stark and Head [1]. Based on morphologic studies, spectral reflectance and other remote sensing information they defined 21 distinctive basalt units, grouped into four formations, the Repsold-, Telemann-, Hermann-, and the Sharp-Formation. We produced a high-resolution Clementine color ratio image, superposed their map, and found that it generally discriminates well between the major spectral basalt types. However, we found that several units can be further subdivided into spectrally different basalt sub-types. The spatial distribution of previously published age data [2, 3] does not correlate with the outline of these spectrally defined units. Therefore we performed new crater size-frequency distribution measurements for spectrally and morphologically defined basalts in order to investigate the stratigraphy of basalts in Oceanus Procellarum. Our crater counts show that active mare volcanism in Oceanus Procellarum occured over a long period of time from about 1.3 b.y. to about 3.6-3.7 b.y. Lichtenberg, a bright ray crater, is partly embayed by basalt flows which cover the bright rays. Consequently, this basalt was thought to be the very youngest basalt, i.e. Copernican in age, and to mark the end of lunar volcanism [4]. However, our data show that the Lichtenberg Basalt is about 2 b.y.
    [Show full text]
  • Lecture 9 Good Morning and Welcome to LLT121 Classical Mythology
    Lecture 9 Good morning and welcome to LLT121 Classical Mythology. In our last exciting class, we were discussing the various sea gods. You’ll recall that, in the beginning, Gaia produced, all by herself, Uranus, the sky, Pontus, the sea and various mountains and whatnot. Pontus is the Greek word for “ocean.” Oceanus is another one. Oceanus is one of the Titans. Guess what his name means in ancient Greek? You got it. It means “ocean.” What we have here is animism, pure and simple. By and by, as Greek civilization develops, they come to think of the sea as ruled by this bearded god, lusty, zesty kind of god. Holds a trident. He’s seriously malformed. He has an arm growing out of his neck this morning. You get the picture. This is none other than the god Poseidon, otherwise known to the Romans as Neptune. One of the things that I’m going to be mentioning as we meet the individual Olympian gods, aside from their Roman names—Molly, do you have a problem with my drawing? Oh, that was the problem. Okay, aside from their Roman names is also their quote/unquote attributes. Here’s what I mean by attributes: recognizable features of a particular god or goddess. When you’re looking at, let’s say, ancient Greek pottery, all gods and goddesses look pretty much alike. All the gods have beards and dark hair. All the goddesses have long, flowing hair and are wearing dresses. The easiest way to tell them apart is by their attributes.
    [Show full text]
  • Volcanic Plume, Not an Asteroid, Likely Created the Moon's Largest Basin 1 October 2014, by Jennifer Chu
    Solving the mystery of the 'man in the moon': Volcanic plume, not an asteroid, likely created the moon's largest basin 1 October 2014, by Jennifer Chu by a massive asteroid. Instead, researchers believe that the angular outline was produced by giant tension cracks in the moon's crust as it cooled around an upwelling plume of hot material from the deep interior. Maria Zuber, the E.A. Griswold Professor of Geophysics and also MIT's vice president for research, says that as cracks occurred, they formed a "plumbing system" in the moon's crust The Moon as observed in visible light (left), topography through which magma could meander to the (center, where red is high and blue is low), and the surface. Magma eventually filled the region's GRAIL gravity gradients (right). The Procellarum region smaller basins, creating what we see today as dark is a broad region of low topography covered in dark spots on the near side of the moon—features that mare basalt. The gravity gradients reveal a giant rectangular pattern of structures surrounding the region. have inspired the popular notion of a "man in the Credit: NASA/Colorado School of moon." Mines/MIT/JPL/Goddard Space Flight Center "A lot of things in science are really complicated, but I've always loved to answer simple questions," says Zuber, who is principal investigator for the New data obtained by NASA's GRAIL mission GRAIL (Gravity Recovery and Interior Laboratory) reveals that the Procellarum region on the near mission. "How many people have looked up at the side of the moon—a giant basin often referred to as moon and wondered what produced the pattern we the "man in the moon"—likely arose not from a see—let me tell you, I've wanted to solve that one!" massive asteroid strike, but from a large plume of magma deep within the moon's interior.
    [Show full text]
  • GRAIL-Identified Gravity Anomalies in Oceanus Procellarum: Insight Into 2 Subsurface Impact and Magmatic Structures on the Moon 3 4 Ariel N
    1 GRAIL-identified gravity anomalies in Oceanus Procellarum: Insight into 2 subsurface impact and magmatic structures on the Moon 3 4 Ariel N. Deutscha, Gregory A. Neumannb, James W. Heada, Lionel Wilsona,c 5 6 aDepartment of Earth, Environmental and Planetary Sciences, Brown University, Providence, RI 7 02912, USA 8 bNASA Goddard Space Flight Center, Greenbelt, MD 20771, USA 9 cLancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, UK 10 11 Corresponding author: Ariel N. Deutsch 12 Corresponding email: [email protected] 13 14 Date of re-submission: 5 April 2019 15 16 Re-submitted to: Icarus 17 Manuscript number: ICARUS_2018_549 18 19 Highlights: 20 • Four positive Bouguer gravity anomalies are analyzed on the Moon’s nearside. 21 • The amplitudes of the anomalies require a deep density contrast. 22 • One 190-km anomaly with crater-related topography is suggestive of mantle uplift. 23 • Marius Hills anomalies are consistent with intruded dike swarms. 24 • An anomaly south of Aristarchus has a crater rim and possibly magmatic intrusions. 25 26 Key words: 27 Moon; gravity; impact cratering; volcanism 1 28 Abstract 29 30 Four, quasi-circular, positive Bouguer gravity anomalies (PBGAs) that are similar in diameter 31 (~90–190 km) and gravitational amplitude (>140 mGal contrast) are identified within the central 32 Oceanus Procellarum region of the Moon. These spatially associated PBGAs are located south of 33 Aristarchus Plateau, north of Flamsteed crater, and two are within the Marius Hills volcanic 34 complex (north and south). Each is characterized by distinct surface geologic features suggestive 35 of ancient impact craters and/or volcanic/plutonic activity.
    [Show full text]
  • Grail-Identified Gravity Anomalies in Procellarum: Insight Into Subsurface Im- Pact and Volcanic/Magmatic Structures on the Moon
    GRAIL-IDENTIFIED GRAVITY ANOMALIES IN PROCELLARUM: INSIGHT INTO SUBSURFACE IM- PACT AND VOLCANIC/MAGMATIC STRUCTURES ON THE MOON. Ariel N. Deutsch1, Gregory A. Neu- mann2, James W. Head1, and Lionel Wilson1,3, 1Department of Earth, Environmental and Planetary Sciences, Brown University, Providence, RI 02912, USA, 2NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA, 3Lan- caster Environment Centre, Lancaster University, Lancaster LA1 4YQ, UK ([email protected]). Introduction: Oceanus Procellarum on the Moon model the crust as being occupied by ~25% volume of hosts four positive Bouguer gravity anomalies (PBGAs) dikes (density contrast of 150 kg/m3) to correspond to that are similar in diameter (~100–120 km), gravita- the GRAIL-derived signal. Given the volume (10,000 tional amplitude (>100 mGal contrast), and shape (ap- m3) of the Marius Hills complex, at least 10 large-vol- proximately circular in planform) (Fig. 1). However, ume dikes are required [4]. The presence of a deep man- these spatially associated PBGAs are characterized by tle reservoir is necessary in our forward model to corre- distinct surface geologies. These four PBGAs are im- late with the magnitude of the anomalies. A long-lived portant in understanding the impact and volcanic/plu- source in the mantle feeding multiple dikes is also con- tonic history of the Moon, in a region of elevated tem- sistent with the generation, ascent, and eruption of peratures due to the Procellarum KREEP Terrane [1]. magma on the Moon [4]. Mantle upwelling: Mare-filled craters are consistent with the circular shapes of the anomalies and the topo- graphic expression of Southern AP [8] and N.
    [Show full text]