Lunar and XXIX 1733.pdf

THE NON-RANDOM DISTRIBUTION OF VOLCANOES. J.F. Rodionova and S.V. Koroteev. Sternberg State Astronomical Institute, 119899 Moscow, Russia. E-mail: [email protected]

Two bands spaced along big circles in- THE SECOND BAND clined at an angle of almost 90 degrees to N Name or Lat/Lon Area x 103 km2 each other and including most of the volcanoes 1 254.6 were exposed on the base of maps (1,2,3). The 2 Hecates 33.4 first one intersects with the equator on the longi- 3 Albor Tholus 19 tude 110 degrees and has an inclination of 54 de- 4 4.0 grees (fig.1). It includes: , Pavonic 5 108.9 Mons, , Uranius Patera, 6 18S 60 6.4 , Tholus, Tyrrhena 7 21S 60 3.0 Patera and others (table 1). The coordinates and 8 27N 126 35.1 areas of the volcanos' basin are determined with 9 1N 136 0.7 the use of maps (1,2,4). The second band in- 10 8S 93 1.7 cludes: Olympus Mons, Elysium Mons, , Albor Tholus, Jovis Tholus and others Two additional bands are connected with the (table ). are also in this band. boundary between highlands and lowlands on . The third circle is inclined at 35 degrees to Table of volcanoes situated in the first and the equator and includes mensae: Deuteronilus, second bands. , Nepentes, Nilosyrtis, Protonilus and ten volcanoes (fig.1). The fourth band which is per- THE FIRST BAND pendicular to the third one includes: Patera Alba, N Name or Lat/Lon Area x 103 km2 Hadriaca Patera, . Many fossae 1 Arsia Mons 131.4 have the same direction as these bands. Sirenum 2 Pavonic Mons 131.4 and Tantalus Fossae are parallel to the first band. 3 Ascraeus Mons 149.1 4 Uranius Patera 46.0 We can suggest the existence of deep fractures 5 Ceraunius Tholus 11.4 situated under these big circles. The mechanism 6 Tharsis Tholus 15.9 of formation of these deep fractures is unknown 7 3.8 but it is possible that the main role is played by: 8 Biblis Patera 15.1 irregular rotation of the planet, preccesion of the 9 Ulyssis Patera 9.2 axis of rotation and the tidal wave. 10 Tyrrhena Patera 45.0 11 44N 62 19.5 Plate tectonics may have a place on Mars (5). 12 18S 116 0.8 Therefore, as on the martian volcanoes may 13 18S 113 1.9 be connected with the tectonic processes along of 14 35S 145 7.6 the boundaries of the plates. 15 38S 148 5.0 16 31S 140 1.9 17 42S 154 1.0 The landing site of Mars Pathfinder is on the 18 41S 159 1.5 third band (19N,33). 19 44N 79 4.3 20 45N 70 3.6 Fig.2 shows the global fracture on Europa 21 37N 75 36.9 looks like a big circle. 22 47N 55 0.2 23 47N 54 0.2 References: (1) Geologic map of western 24 53S 179 0.3 equatoria, eastern equatorial and polar re- gions,1:15 000 000, USGS,1986. (2) Atlas of Mars, 1:15 000 000 Topographic series, USGS, 1991. (3) Map of Mars showing channels and possible paleolake basins, USGS, 1995. (4) Topographic Map of Mars, 1:2 000 000, USGS, 1986. (5) Sleep N. H., Norman M.D. (1994) Mar- tian plate tectonics. JGR, 99,N3,pp. 5639-5655. Lunar and Planetary Science XXIX 1733.pdf

THE NON-RANDOM DISTRIBUTION OF MARTIAN VOLCANOES. J.F. Rodionova et al.

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