DOCSLIB.ORG

Resurfacing of Procellarum-Imbrium Region by Tectonism and Volcanism: the Role of the Basin-Radial Fracture Zones Around the Imbrium Basin

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Resurfacing of Procellarum-Imbrium Region by Tectonism and Volcanism: the Role of the Basin-Radial Fracture Zones Around the Imbrium Basin Lunar and Planetary Science XLVIII (2017) 1710.pdf RESURFACING OF PROCELLARUM-IMBRIUM REGION BY TECTONISM AND VOLCANISM: THE ROLE OF THE BASIN-RADIAL FRACTURE ZONES AROUND THE IMBRIUM BASIN. F. Zhang and M.-H. Zhu, Space Science Institute, Macau University of Science and Technology, Taipa, Macau ([email protected]). Introduction: The debate regarding to the origin of the Oceanus Procellarum (the largest basalt concen- tration area on the Moon) is still ongoing today. Two formation mechanisms have been proposed: impact [1, 2, 3], and intrusion and crust rifting [4]. But, the de- tailed processes responsible for the resurfacing of Pro- cellarum are yet still unclear. For this purpose, we try to establish a sequence of events accounting for the current surficial state of spatial distribution of volcanic materials in Oceanus Procellarum. Commonly, volcano concentration areas have rift zones underlain by swarms of dikes or other varying scale intrusions. The presence of mantle-derived mafic dikes on the Moon is mainly inferred from associated volcanic morphology and surface deformation [5]. Spatial arrangement of dike-related lineaments reflect the record of fracture system in the lunar crust. Fractures in radial pattern on the Moon are frequently associated with a sufficiently Fig. 1 LROC WAC mosaic for the Procellarum- large basin [6] forming a subset of the Moon's NE-SW Imbrium region. Six large shield volcanos (Rumker, and NW-SE trending grid system [7]. Aristarchus, Prinz, Marius, Kepler, and Hortensius) are Impact-induced faults are nearly ubiquitous over outlined by ellipse. Three basin-radial volcanic belt large areas on the terrestrial planets [8]. These fault zones GM, DPA, and EMK are marked by white systems are preferred sites for late deformation in re- stripes. sponse to lithospheric stresses generated by other pro- Data and Methods: We use data from Lunar Re- cesses. Melosh [6] suggested that faults formed during connaissance Orbiter (LRO) mission to trace surface the Imbrium basin continued to be active for at least expressions of dike segments (structurally controlled 600 Ma on the Moon, inferred from the observation of by large event) to establish the subsurface radial faults cutting mare basalts, ~ 600 Ma after the dike/fracture/fissure systems around the Imbrium basin. formation of Imbrium basin [9]. For the Imbrium basin, Three volcanic belt zones are defined and character- the radial fracture patterns start from the interior [10] ized by abundant surficial dike-related structures. Two and extend further to a distance of ~1 radius beyond relevant volcano-tectonic features characterize the the outmost ring. Subsurface radial dikes detected from three basin-radial fracture zones morphologically: (1) Gravity Recovery and Interior Laboratory (GRAIL) dike-related clusters of aligned eruptive vents (such as data [11] support this interpretation. However, the de- rilles' head depressions, cones and domes) and graben- tection of smaller dikes can not be resolved by the fissures; and (2) sinuous rilles and IMPs, which are GRAIL data due to the limited spatial resolution. Here, commonly related to volcanic structures [12, 5]. These we use linear dike-related surface expressions (linea- volcanic features are spatially associated with the maria ments) to infer the spatial distribution of subsurface around them. All the original data and resulting data dikes/fissures/fractures at the western marginal zone of are processed in ArcGIS software. the Imbrium basin, a transitional region from Mare Results: The Gruithuisen-Mairan (GM) volcanic Imbrium to Oceanus Procellarum (see Fig. 1). This belt zone contains 12 sinuous rilles, 7 non-mare more class of fragmented dike swarms can be recognized as silicic domes (Gruithuisen and Mairan domes), 1 mare the signature of major magmatic events, in many in- dome, 2 cones, and more than 50 gas-release erup- stances linked to the Imbrium impact-induced faults tion/deposit related depressions (IMPs). Similar to that may have persisted as zones of lithospheric weak- these dome locations, some source depressions of sinu- ness. The purpose of this work is to provide much ous rilles have elongated forms displaying the preferen- needed constraint for the major magmatic and tectonic tial direction radial to the Imbrium basin. events responsible for the long-term resurfacing of The Delisle-Prinz-Aristarchus (DPA) volcanic belt Procellarum-Imbrium region over geologic time scales. zone is a positive-relief region of ~100 km in width Lunar and Planetary Science XLVIII (2017) 1710.pdf and extends from northeast of Delisle crater to the Ar- the maximum stress within the lithosphere may be istarchus Plateau. The main features in DPA region switched to a direction parallel to a meridian from a include: (1) a pre-mare highland plateau-Aristarchus direction perpendicular to a meridian [20]. Conse- [5], (2) highland crater Prinz and mountains Harbinger, quently, with time and cooling of lithosphere, the ori- remnants of outer Imbrium rims, (3) basin-radial linear entations of linear tectonic structures show a wide- rille (graben) segments, (4) distinctive alignment of spread pattern of concentric and radial to the Imbrium vents, and (5) some IMPs within or around two source basin, such as a large-scale Imbrium pattern of graben vents at the Prinz site. The observation of sinuous rilles [6], many of which are underlain by a dike wider than at the end of some linear rille (graben) segments indi- 100 m that likely penetrate the lunar crust down to cates the direct evidence for the volcanic origin of the depth of ~20 km [13]. rille (graben) underlain by subsurface dike [13] or be- Conclusions: This study has identified three vol- ing a collapsed lava tube or a fissure vent. Caldera-like canic belt zones at the western margin of the Imbrium pit and vent area near the Prinz [14] would be the erup- basin. These belts represent basin-related rift and frac- tive center feeding the surrounding mare plains of Oce- ture zones characterised by radiating lineament systems anus Procellarum and Mare Imbrium. or volcanic features arranged in linear distribution. Euler-Mayer-Kepler (EMK) rift and fracture zones Imbrium basin-radial dike related volcanic eruptions are highly fractured areas allowing multiple pathways are most likely to be responsible for the long history of for magma to the surface. In the areas numerous linear emplacement of mare basalts in the Procellarum- volcanic features are radial to the Imbrium basin and Imbrium region. Imbrium impact event play a signifi- shape the surface tectonically and volcanologically cantly important role in reshaping the nearside crust of across about half of a million square kilometers. These the Moon. The fractured lunar crust provides direct volcanic lineaments (17 cone rows (line of spatter pathways for magma ascending to the surface as the cones along fissure vent), 15 linear rilles (graben), 5 pit Imbrium basin evolves. The unique thermal setting and (crater) chains, and 4 fissure vents) represent subparal- a thin lunar crust of the region allow the post-Imbrium lel dikes over a broad area displaying elliptical bounda- volcanism to be extended within a prolonged duration ry. The long axis of both elliptical fracture zones ex- in lunar history. hibit the Imbrium basin-radial pattern. Many cones Acknowledgments: This work was supported by display elongated summit vents oriented radially with the Science and Technology Development Fund of respect to the Imbrium basin. Macau (075/2014/A2 and 039/2013/A2). Discussion: The basin-concentric and basin-radial References: [1] Cadogan P. (1974) Nature, 250, orientations of dike-related lineaments around the basin 315–316. [2] Whitaker E. (1980) In: Multi-ring Basins: can be ascribed to the stress differences in the lunar Formation and Evolution, 414, p.101. [3] Wilhelms, D. crust as the Imbrium basin evolves. The Imbrium im- (1987) US Geol. Surv. Prof. Pap., 1348, 1–302. [4] pact site was a long-lived hotspot [15] with a thin crust Andrews-Hanna J. et al. (2014) Nature, 514 (7520) [16]. The initiation of the radial tensional fractures or 68–71. [5] Head J. and Wilson L. (2016) Icarus, 283, faults is believed to occur at the time of the Imbrium 176–223. [6] Melosh H. (1976) LPS VII, 2967–2982. event due to a broad domal uplift of the region around [7] Strom R. (1964) Commun. Lunar Planet Lab, 2, the basin resulting from stress relief (stress relaxation) 205–216. [8] Solomon S. and Duxbury E. (1987) JGR, at depth [17, 6]. The domical topography formed at the 92 (B4). [9] Taylor S. (1975) New York, Pergamon surface due to the shallow emplacement of magma Press, Inc., p.390. [10] Zhang F. et al. (2016) EPSL, and/or lava accumulation on the top and flanks has 445, 13–27. [11] Andrew-Hanna J. et al. (2013) Sci- been clearly identified as large shield volcanos on the ence 339 (6120), 675–678. [12] Braden S. et al. (2014) Moon [14]. Early in the major period of mare volcan- Nat. Geosci., 7 (11), 787–791. [13] Klimczak C. (2014) ism (~3.9-3.1 Ga ago, [18]), the extension state of the Geology, 42 (11), 963–966. [14] Spudis P. et al. (2013) Moon [19], regional extensional stresses caused by JGR, 118 (5), 1063–1081. [15] Wieczorek M. and post-Imbrium-impact uplift and viscous relaxation (fa- Phillips R. (2000) JGR, 105 (E8), 20417–20430. [16] cilitate dike intrusion), and the viscoelastic nature of Wieczorek M. et al. (2013) Science, 339 (6120), 671– the lithosphere would allow regional deformation to 675. [17] Mason R. (1976) Proc. Geol. Assoc., 87 (2), take place over a long period of time [20], in accord- 161–168. [18] Hiesinger H. (2011) Spec. Pap. Geol. ance with the elevated heat flux in this region (always Soc. Am, 477, 1–51.
Load more

Recommended publications
  • S·O:3::~:~T~!E~~ W!~1~;Dmi~E Te~~- ~~:C:#R.:~~ I~Rt~:Rh~4I!I~Ts · ~Perin,~Ne 'R~9.Ioh ·± ~ .~I.G,Ll.T · I;>E J5est Aqhi'ev~Q:J
    ... , .~ ~70 10029 ~~. '' .. M ·]\.l;la~y~;:~,i·s o.f · th~ Sqi~:ntiiib D~TE: O<::tdbe.r 13, · 1970 ob:j e'¢.tive$· · and J?.:i;-OJ?ps~d +,.an~iin<J . s:i.. tes irt the. aadley.:.Ap,ennine Re:gion FROM: J . w. lie ad case:34o .) The possible scientiEic objectives at the Hadley~ Ap~nnine region a·re out:~ined: CI;J:ld incl,~de. tlle Ap.el}n:~ne Mo,un;t;;tins 1 H~dley. R.±l:le, mar.e mai;.erial~· lladleyf] c qr~·teri yol·can·ic ra:.Pd'"" :~;s·o:3::~:~t~!e~~ w!~1~;dmi~e te~~- ~~:C:#R.:~~ i~rt~:rH~4i!i~ts · ~perin,~ne 'r~9.ioh ·± ~ .~i.g,ll.t · i;>e J5est aqhi'ev~q:j . ·ba$¢d: on cli;ff.e;temt .irit¢]tpret:a~ions of t:h~. origin {Jf :J:hese va,r$.o\lS fe~tures. Five la'ii~i:hg po;iri·ts are evcl;:l:U.atea: in terms of· t:J:ie, ..$:1;:1,3, ty to acnlev¢ the 'sq;lentific o_bjectfves bo~ on a rover .and a walkil19 mii.s;.. sion. ·c .0 ,.... :.. ..,... .. ··ti:]9::ijii11·-·· uncla:s 12811' .B"'E~I¥-:t,;.;CPM~M • .INC. • ss5· ~;ENFAt4T' P~~~~~I~~::s:y;1 . ~As~IW~ro~~ o:.C: -~01)2~.· .. SUBJECT! oAT£: octo.b~r 1:3~ · 1970 .FROMi j.· W. Head t. GEN:E!M:4 li'~cii~yt~Ap~ni1.ine · 'l'h.~ ~pepf!irie Mol;tn-ta.in!3 rise. up to -~' km· above th.e.
    [Show full text]
  • TRANSIENT LUNAR PHENOMENA: REGULARITY and REALITY Arlin P
    The Astrophysical Journal, 697:1–15, 2009 May 20 doi:10.1088/0004-637X/697/1/1 C 2009. The American Astronomical Society. All rights reserved. Printed in the U.S.A. TRANSIENT LUNAR PHENOMENA: REGULARITY AND REALITY Arlin P. S. Crotts Department of Astronomy, Columbia University, Columbia Astrophysics Laboratory, 550 West 120th Street, New York, NY 10027, USA Received 2007 June 27; accepted 2009 February 20; published 2009 April 30 ABSTRACT Transient lunar phenomena (TLPs) have been reported for centuries, but their nature is largely unsettled, and even their existence as a coherent phenomenon is controversial. Nonetheless, TLP data show regularities in the observations; a key question is whether this structure is imposed by processes tied to the lunar surface, or by terrestrial atmospheric or human observer effects. I interrogate an extensive catalog of TLPs to gauge how human factors determine the distribution of TLP reports. The sample is grouped according to variables which should produce differing results if determining factors involve humans, and not reflecting phenomena tied to the lunar surface. Features dependent on human factors can then be excluded. Regardless of how the sample is split, the results are similar: ∼50% of reports originate from near Aristarchus, ∼16% from Plato, ∼6% from recent, major impacts (Copernicus, Kepler, Tycho, and Aristarchus), plus several at Grimaldi. Mare Crisium produces a robust signal in some cases (however, Crisium is too large for a “feature” as defined). TLP count consistency for these features indicates that ∼80% of these may be real. Some commonly reported sites disappear from the robust averages, including Alphonsus, Ross D, and Gassendi.
    [Show full text]
  • 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]
  • Relative Ages
    CONTENTS Page Introduction ...................................................... 123 Stratigraphic nomenclature ........................................ 123 Superpositions ................................................... 125 Mare-crater relations .......................................... 125 Crater-crater relations .......................................... 127 Basin-crater relations .......................................... 127 Mapping conventions .......................................... 127 Crater dating .................................................... 129 General principles ............................................. 129 Size-frequency relations ........................................ 129 Morphology of large craters .................................... 129 Morphology of small craters, by Newell J. Fask .................. 131 D, method .................................................... 133 Summary ........................................................ 133 table 7.1). The first three of these sequences, which are older than INTRODUCTION the visible mare materials, are also dominated internally by the The goals of both terrestrial and lunar stratigraphy are to inte- deposits of basins. The fourth (youngest) sequence consists of mare grate geologic units into a stratigraphic column applicable over the and crater materials. This chapter explains the general methods of whole planet and to calibrate this column with absolute ages. The stratigraphic analysis that are employed in the next six chapters first step in reconstructing
    [Show full text]
  • Download (276Kb)
    OUT THERE WALKING ON THE MOON RAMGOPAL (RAMG) VALLATH This is the story k Chotisi Asha — one small hope, that is Fig.1) that is designed to travel from the of a private Ewhat I am named: ECA for short. But the Earth to the Moon, land there and drive Indian company, hope I represent is anything but small. I around on the moon. By the time you read TeamIndus, that represent the hopes of 1.3 billion people of this story, I will be on my way to the moon or is competing in India as they make giant strides across all would have already landed there. the Google Lunar facets of science and I represent the hope of XPRIZE challenge I was conceived and built in the office of humanity to spread wings, move out of the to land a rover on the young start-up company, TeamIndus, in the moon. security of mother Earth and settle on distant Bengaluru, India. It all started when Google planets. I am a small but giant step in that announced the Lunar XPRIZE (GLXP for direction. You see, I am a small rover (refer short), a global competition. It is a $30M Fig. 1. ECA (Short for Ek Chotisi Asha- one small hope) is the moon rover designed by TeamIndus. Credits: TeamIndus. License: Copyrighted and used with permission. 94 - REDISCOVERING SCHOOL SCIENCE Jan 2018 Fig. 2. ECA along with the spacecraft, photographed at the TeamIndus facility in Bangalore. Credits: TeamIndus. License: Copyrighted and used with permission. competition to challenge and inspire twenty people in the team (refer Fig.3), that was also designed by TeamIndus.
    [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]
  • 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]
  • Tectonic Evolution of Northwestern Imbrium of the Moon That Lasted In
    Daket et al. Earth, Planets and Space (2016) 68:157 DOI 10.1186/s40623-016-0531-0 FULL PAPER Open Access Tectonic evolution of northwestern Imbrium of the Moon that lasted in the Copernican Period Yuko Daket1* , Atsushi Yamaji1, Katsushi Sato1, Junichi Haruyama2, Tomokatsu Morota3, Makiko Ohtake2 and Tsuneo Matsunaga4 Abstract The formation ages of tectonic structures and their spatial distributions were studied in the northwestern Imbrium and Sinus Iridum regions using images obtained by Terrain Camera and Multiband Imager on board the SELENE spacecraft and the images obtained by Narrow Angle Camera on board LRO. The formation ages of mare ridges are constrained by the depositional ages of mare basalts, which are either deformed or dammed by the ridges. For this purpose, we defined stratigraphic units and determined their depositional ages by crater counting. The degradation levels of craters dislocated by tectonic structures were also used to determine the youngest limits of the ages of the tectonic activities. As a result, it was found that the contractions to form mare ridges lasted long after the deposition of the majority of the mare basalts. There are mare ridges that were tectonically active even in the Copernican Period. Those young structures are inconsistent with the mascon tectonics hypothesis, which attributes tectonic deforma- tions to the subsidence of voluminous basaltic fills. The global cooling or the cooling of the Procellarum KREEP Ter- rane region seems to be responsible for them. In addition, we found a graben that was active after the Eratosthenian Period. It suggests that the global or regional cooling has a stress level low enough to allow the local extensional tectonics.
    [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]