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North Ray (crater)

January 01, 1970

North Ray crater is a small crater in the Descartes Highlands of the Moon visited by the astronauts of Apollo 16. The name of the crater was formally adopted by the IAU in 1973.[1] It is the largest crater sampled by astronauts during the Apollo program.

North Ray
Apollo 16 image
Coordinates8°49′S 15°29′E / 8.82°S 15.48°E / -8.82; 15.48
Diameter950 m[1]
Depth240 m
EponymAstronaut-named feature
LRO image

The Apollo 16 Lunar Module (LM) Orion landed between North Ray and South Ray craters on April 21, 1972. The astronauts John Young and Charles Duke explored the area between the craters over the course of three EVAs using a Lunar Roving Vehicle, or rover. They visited North Ray on EVA 3, at station 11, about 4.4 km north of the landing site. On the way, they drove along the rim of the similar sized but older crater Palmetto, which is approximately 3 km south of North Ray.

North Ray crater is approximately 1 km in diameter and approximately 240 m deep.[2] The astronauts observed that the upper 50 m of the slope is gentle, but that it becomes steep below 50 m, and they could not observe the bottom. The inner slopes are covered by boulders up to 5 m across. A huge (10 m high x 20 m long) boulder, known as House Rock, lies near the southeastern rim. A smaller boulder that is almost certainly a fragment of House Rock is officially known as South Boulder, but unofficially known as Outhouse Rock.[3] The ray system, which can be seen from orbit, was not obvious on the ground.

North Ray cuts into the Cayley Formation of Imbrian age,[4] but the crater itself is much younger, of Copernican age, based on the presence of rays. (See also section on age below.)

Panorama of North Ray Crater from the south rim. House Rock is at right edge. Compare with the map below.
Planimetric map of Station 11 from the Apollo 16 Preliminary Science Report. X indicates sample locations, 5-digit numbers are LRL sample numbers, rectangle is lunar rover (dot indicates TV camera), black spots are large rocks, dashed lines are crater rims or other topographic features, and triangles are panorama stations.

Gallery edit

  •  
    Geologic map of North Ray crater
  •  
    Oblique Apollo 14 image, facing east
  •  
    Telephoto image of rocks in the interior walls of the crater
  •  
    John Young using the rake tool to collect a sample (67700) at the southeast rim, with the rover at the central horizon, and white breccia boulders at the right horizon
  •  
    White breccia boulder along the south rim of the crater, showing typical dark-clast population, rounded, unjointed surfaces, and well-developed fillet
  •  
    House rock as viewed from the white breccia boulders (looking northeast)
  •  
    East side of House Rock

Age edit

 
Lunar sample 67955 was used to date the impact at about 50 million years ago.

Based on sample 67955,[5] a noritic anorthosite collected from Outhouse Rock, the impact that created North Ray crater was about 50 million year ago. This is based on the measured duration of the rock's exposure to cosmic rays.[6] The rock itself is dated at 4.20 ± 0.07 b.y. by Sm/Nd radiometric dating.[7]

Samples edit

 
Lunar sample 67016, found lying on the ground next to the rover
 
Lunar sample 67475, a clast was removed from one of the white breccia boulders shown above
 
Lunar sample 67559, found within rake sample 67510
 
Lunar sample 67729, found within rake sample 67710

The following samples were collected from North Ray Crater (Station 11), as listed in Table 6-II of the Apollo 16 Preliminary Science Report,[3] which does not include samples smaller than 25 g weight (of which there were many). Sample type, lithology, and descriptions are from the Lunar Sample Atlas of the Lunar and Planetary Institute.[8]

Sample Sample Type In Situ Photo Lithology Description
67015 rake   breccia Fragmental matrix breccia, mostly feldspar, but with a wide range of highland lithologies represented as loose clasts in the matrix; have been dated at 3.9 b.y. and the breccias, itself, has had an exposure to cosmic ray of 51 m.y.
67016 rock   breccia Feldspathic fragmental breccia with both light and dark clasts, and is 3.95 b.y. old with an exposure age of 50 m.y.
67035 rock - Fragmental breccia Very friable, light matrix breccia; was found to be 3.95 b.y.
67055 rock   breccia Black and white breccia; high trace element content, but has not been dated.
67075 rock   anorthite Lunar sample 67075 is very friable. Detailed petrographic description showed that the sample may be a mixture of closely related anorthositic rocks from a layered igneous intrusion, and it has been shown to be 4.47 b.y. old, with about 50 m.y. exposure to cosmic rays
67095 rock   impact melt breccia A glass-coated basaltic impact melt or "bomb" that has not been dated.
67115 rake   breccia Glass coat is rather thick, but has been fractured and broken off by micrometeorite bombardment
67210 (67215) rake   breccia White polymict breccia made up of mostly calcic plagioclase and a few relict lithic clasts and has many zap pits on top and bottom
67230 (67235) rock   impact melt breccia 67235 is a large special sample that was collected to study the outer surface of a lunar rock
67415 rake   breccia According to Lindstrom and Lindstrom (1986), 67415 is a lightly-shocked, granulitic breccia with a cataclastic matrix.
67435 rock   breccia Grey matrix breccias with both dark and light clasts
67455 rock   breccia Very friable, white polymict feldspathic breccia
67475 rock   breccia A tough purplish-grey, glassy breccia
67515 rake - breccia Friable, chalky white rock containing lithic fragments of cataclastic anorthosite and feldspathic granulite
67549 rake - breccia Porous and rounded with a light matrix and both light and dark clasts
67556 rake - breccia A friable micropoikilitic impact melt with intrusive glass veins. It has a micrometeorite crater.
67559 rake - basalt Igneous texture indicating that it cooled from a liquid, albeit, highly aluminous. It contains a trace of Ni, Ir and Au and has been dated at 3.76 ± 0.04 b.y., which makes it a critical sample.
67605 rake - breccia Relatively large friable, white particle about the size, shape and color of a golf ball
67627 rake - breccia Glass-cemented aggregates
67628 rake - breccia Glass bombs (renumbered to 4 separate samples 67685-67688)
67629 rake - breccia Glass-cemented aggregates (renumbered to 4 separate samples 67629, 67695, 67696, 67697)
67647 rake - breccia Relatively coherent with many zap pits and has glass clasts, and glass in the matrix
67718 rake - breccia Abundant clasts of plagioclase set in an aphanitic matrix
67729 rake - breccia Vesicular glass breccia with significant clasts, and has the appearance of a "glass bomb". It has zap pits on all sides
67915 rock - breccia Composed of white and grey breccias; both are polymict (Taylor and Mosie 1979), cemented by shock-melted glass and is also cut with thin black glass veins
67935 rock   breccia Thin veins of black glass, texture of fine-grained subophitic basalt
67936 rock - breccia Thin veins of black glass, texture of fine-grained subophitic basalt
67937 rock - breccia Thin veins of black glass, texture of fine-grained subophitic basalt
67955 rock   breccia Exterior surface has a thin brown patina with micrometeorite pits; has been dated at 4.2 b.y. with exposure to cosmic rays for ~ 50 m.y. (age of North Ray Crater)
67975 rock   fragmental breccia Irregularly shaped rock with approximately equal amounts of pale gray, fragmental, friable breccia and a coating of frothy, clast-rich glass.

External links edit

  • Geology of North Ray Crater, Section D2 of Geological Survey Professional Paper 1048, by George E. Ulrich. 1981.
  • Apollo 16 Traverses, 78D2S2(25), Lunar and Planetary Institute

References edit

  1. ^ a b North Ray, Gazetteer of Planetary Nomenclature, International Astronomical Union (IAU) Working Group for Planetary System Nomenclature (WGPSN)
  2. ^ Apollo 16 Landing Area, 78D2S1(50), NASA Lunar Topophotomap. Published by The Defense Mapping Agency, November 1974. Available from Lunar and Planetary Institute.
  3. ^ a b Apollo 16 Preliminary Science Report (NASA SP-315), 1972
  4. ^ Geologic Map of the Apollo 16 (Descartes) Landing Area by Apollo Field Geology Investigation Team (D. P. Elston, E. L. Boudette, J. P. Schafer), United States Geological Survey, April 1972
  5. ^ 67955 Summary Sheet available from Lunar and Planetary Institute
  6. ^ Drozd R.J., Hohenberg C.M., Morgan C.J. and Ralston C.E. (1974) Cosmic-ray exposure history at the Apollo 16 and other lunar sites: lunar surface dynamics. Geochim. Cosmochim. Acta 38, 1625-1642.
  7. ^ Norman M.D., Shih C.-Y., Nyquist L.E., Bogard D.D. and Taylor L.A. (2007) Early impacts on the moon: Crystallization ages of Apollo 16 melt breccias (abs#1991). Lunar Planet. Sci. XXXVIII Lunar & Planetary Institute, Houston. (LPSC 2007 web page)
  8. ^ Lunar Sample Atlas, Lunar and Planetary Institute

January 01, 1970
north, crater, north, crater, small, crater, descartes, highlands, moon, visited, astronauts, apollo, name, crater, formally, adopted, 1973, largest, crater, sampled, astronauts, during, apollo, program, north, rayapollo, imagecoordinates8, 48diameter950, dept. North Ray crater is a small crater in the Descartes Highlands of the Moon visited by the astronauts of Apollo 16 The name of the crater was formally adopted by the IAU in 1973 1 It is the largest crater sampled by astronauts during the Apollo program North RayApollo 16 imageCoordinates8 49 S 15 29 E 8 82 S 15 48 E 8 82 15 48Diameter950 m 1 Depth240 mEponymAstronaut named feature LRO image The Apollo 16 Lunar Module LM Orion landed between North Ray and South Ray craters on April 21 1972 The astronauts John Young and Charles Duke explored the area between the craters over the course of three EVAs using a Lunar Roving Vehicle or rover They visited North Ray on EVA 3 at station 11 about 4 4 km north of the landing site On the way they drove along the rim of the similar sized but older crater Palmetto which is approximately 3 km south of North Ray North Ray crater is approximately 1 km in diameter and approximately 240 m deep 2 The astronauts observed that the upper 50 m of the slope is gentle but that it becomes steep below 50 m and they could not observe the bottom The inner slopes are covered by boulders up to 5 m across A huge 10 m high x 20 m long boulder known as House Rock lies near the southeastern rim A smaller boulder that is almost certainly a fragment of House Rock is officially known as South Boulder but unofficially known as Outhouse Rock 3 The ray system which can be seen from orbit was not obvious on the ground North Ray cuts into the Cayley Formation of Imbrian age 4 but the crater itself is much younger of Copernican age based on the presence of rays See also section on age below Panorama of North Ray Crater from the south rim House Rock is at right edge Compare with the map below Planimetric map of Station 11 from the Apollo 16 Preliminary Science Report X indicates sample locations 5 digit numbers are LRL sample numbers rectangle is lunar rover dot indicates TV camera black spots are large rocks dashed lines are crater rims or other topographic features and triangles are panorama stations Contents 1 Gallery 2 Age 3 Samples 4 External links 5 ReferencesGallery edit nbsp Geologic map of North Ray crater nbsp Oblique Apollo 14 image facing east nbsp Telephoto image of rocks in the interior walls of the crater nbsp John Young using the rake tool to collect a sample 67700 at the southeast rim with the rover at the central horizon and white breccia boulders at the right horizon nbsp White breccia boulder along the south rim of the crater showing typical dark clast population rounded unjointed surfaces and well developed fillet nbsp House rock as viewed from the white breccia boulders looking northeast nbsp East side of House RockAge edit nbsp Lunar sample 67955 was used to date the impact at about 50 million years ago Based on sample 67955 5 a noritic anorthosite collected from Outhouse Rock the impact that created North Ray crater was about 50 million year ago This is based on the measured duration of the rock s exposure to cosmic rays 6 The rock itself is dated at 4 20 0 07 b y by Sm Nd radiometric dating 7 Samples edit nbsp Lunar sample 67016 found lying on the ground next to the rover nbsp Lunar sample 67475 a clast was removed from one of the white breccia boulders shown above nbsp Lunar sample 67559 found within rake sample 67510 nbsp Lunar sample 67729 found within rake sample 67710 The following samples were collected from North Ray Crater Station 11 as listed in Table 6 II of the Apollo 16 Preliminary Science Report 3 which does not include samples smaller than 25 g weight of which there were many Sample type lithology and descriptions are from the Lunar Sample Atlas of the Lunar and Planetary Institute 8 Sample Sample Type In Situ Photo Lithology Description 67015 rake nbsp breccia Fragmental matrix breccia mostly feldspar but with a wide range of highland lithologies represented as loose clasts in the matrix have been dated at 3 9 b y and the breccias itself has had an exposure to cosmic ray of 51 m y 67016 rock nbsp breccia Feldspathic fragmental breccia with both light and dark clasts and is 3 95 b y old with an exposure age of 50 m y 67035 rock Fragmental breccia Very friable light matrix breccia was found to be 3 95 b y 67055 rock nbsp breccia Black and white breccia high trace element content but has not been dated 67075 rock nbsp anorthite Lunar sample 67075 is very friable Detailed petrographic description showed that the sample may be a mixture of closely related anorthositic rocks from a layered igneous intrusion and it has been shown to be 4 47 b y old with about 50 m y exposure to cosmic rays 67095 rock nbsp impact melt breccia A glass coated basaltic impact melt or bomb that has not been dated 67115 rake nbsp breccia Glass coat is rather thick but has been fractured and broken off by micrometeorite bombardment 67210 67215 rake nbsp breccia White polymict breccia made up of mostly calcic plagioclase and a few relict lithic clasts and has many zap pits on top and bottom 67230 67235 rock nbsp impact melt breccia 67235 is a large special sample that was collected to study the outer surface of a lunar rock 67415 rake nbsp breccia According to Lindstrom and Lindstrom 1986 67415 is a lightly shocked granulitic breccia with a cataclastic matrix 67435 rock nbsp breccia Grey matrix breccias with both dark and light clasts 67455 rock nbsp breccia Very friable white polymict feldspathic breccia 67475 rock nbsp breccia A tough purplish grey glassy breccia 67515 rake breccia Friable chalky white rock containing lithic fragments of cataclastic anorthosite and feldspathic granulite 67549 rake breccia Porous and rounded with a light matrix and both light and dark clasts 67556 rake breccia A friable micropoikilitic impact melt with intrusive glass veins It has a micrometeorite crater 67559 rake basalt Igneous texture indicating that it cooled from a liquid albeit highly aluminous It contains a trace of Ni Ir and Au and has been dated at 3 76 0 04 b y which makes it a critical sample 67605 rake breccia Relatively large friable white particle about the size shape and color of a golf ball 67627 rake breccia Glass cemented aggregates 67628 rake breccia Glass bombs renumbered to 4 separate samples 67685 67688 67629 rake breccia Glass cemented aggregates renumbered to 4 separate samples 67629 67695 67696 67697 67647 rake breccia Relatively coherent with many zap pits and has glass clasts and glass in the matrix 67718 rake breccia Abundant clasts of plagioclase set in an aphanitic matrix 67729 rake breccia Vesicular glass breccia with significant clasts and has the appearance of a glass bomb It has zap pits on all sides 67915 rock breccia Composed of white and grey breccias both are polymict Taylor and Mosie 1979 cemented by shock melted glass and is also cut with thin black glass veins 67935 rock nbsp breccia Thin veins of black glass texture of fine grained subophitic basalt 67936 rock breccia Thin veins of black glass texture of fine grained subophitic basalt 67937 rock breccia Thin veins of black glass texture of fine grained subophitic basalt 67955 rock nbsp breccia Exterior surface has a thin brown patina with micrometeorite pits has been dated at 4 2 b y with exposure to cosmic rays for 50 m y age of North Ray Crater 67975 rock nbsp fragmental breccia Irregularly shaped rock with approximately equal amounts of pale gray fragmental friable breccia and a coating of frothy clast rich glass External links editGeology of North Ray Crater Section D2 of Geological Survey Professional Paper 1048 by George E Ulrich 1981 Apollo 16 Traverses 78D2S2 25 Lunar and Planetary InstituteReferences edit a b North Ray Gazetteer of Planetary Nomenclature International Astronomical Union IAU Working Group for Planetary System Nomenclature WGPSN Apollo 16 Landing Area 78D2S1 50 NASA Lunar Topophotomap Published by The Defense Mapping Agency November 1974 Available from Lunar and Planetary Institute a b Apollo 16 Preliminary Science Report NASA SP 315 1972 Geologic Map of the Apollo 16 Descartes Landing Area by Apollo Field Geology Investigation Team D P Elston E L Boudette J P Schafer United States Geological Survey April 1972 67955 Summary Sheet available from Lunar and Planetary Institute Drozd R J Hohenberg C M Morgan C J and Ralston C E 1974 Cosmic ray exposure history at the Apollo 16 and other lunar sites lunar surface dynamics Geochim Cosmochim Acta 38 1625 1642 Norman M D Shih C Y Nyquist L E Bogard D D and Taylor L A 2007 Early impacts on the moon Crystallization ages of Apollo 16 melt breccias abs 1991 Lunar Planet Sci XXXVIII Lunar amp Planetary Institute Houston LPSC 2007 web page Lunar Sample Atlas Lunar and Planetary Institute Retrieved from https en wikipedia org w index php title North Ray crater amp oldid 1199123459, wikipedia, wiki, book, books, library,

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