Refine your search
Collections
Co-Authors
Journals
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z All
Desai, Ami J.
- Lunar Crater Ejecta Distribution and Characterization Using Mini-RF and LROC-WAC Data
Abstract Views :255 |
PDF Views:83
Authors
Affiliations
1 PLANEX, Physical Research Laboratory, Ahmedabad 380 009, IN
1 PLANEX, Physical Research Laboratory, Ahmedabad 380 009, IN
Source
Current Science, Vol 107, No 5 (2014), Pagination: 824-831Abstract
A detailed quantification of ejecta matter for small craters (<6 km) on the basis of its amount of spatial deposition has been attempted in this study. We used scattering information derived from circular polarization ratio (CPR) and displaying intensity (S1) from Miniature Radio Frequency (Mini-RF) instrument on-board Lunar Reconnaissance Orbiter (LRO), to characterize the radar backscatter of a large number of craters from Rimae Sirsalis, a highland-mare mixed region for deriving spatial ejecta blanket coverage. The radar derived ejecta blanket extent has been further compared with the amount derived by optical sensor for understanding and assessing the relative merits. In order to accurately estimate the total ejecta deposition, its characterization into finer and coarser material has also been done. We have studied the relation between the measured ejecta extents to the crater geometrical parameters and observed a strong relation between the crater ejecta extent and crater diameter using power or polynomial function.Keywords
Impact Processes, Lunar Crater, Planetary Dynamics, Radar, Spatial Ejecta Distribution.Full Text
- Impact Ejecta Characterization for Small-Sized Fresh and Degraded Lunar Craters Using Radar Data
Abstract Views :225 |
PDF Views:82
Authors
Affiliations
1 PLANEX, Physical Research Laboratory, Ahmedabad 380 009, IN
1 PLANEX, Physical Research Laboratory, Ahmedabad 380 009, IN
Source
Current Science, Vol 110, No 10 (2016), Pagination: 1929-1938Abstract
Ejecta distribution studies for large-sized (>10 km) lunar craters have been carried out earlier, but simi-lar studies on smaller craters are lacking mainly due to data resolution limitations. Here we present a de-tailed quantification on spatial deposition of ejecta for small-sized lunar craters (<6 km). Using data from Mini RF instrument on-board NASA's Lunar Recon-naissance Orbiter, four Stokes parameters that differ-entiate and describe the observed backscattered electromagnetic field are calculated. We use the first Stokes parameter to investigate and estimate the spa-tial ejecta distribution for 98 small-sized fresh and de-graded craters from mare and highland regions. It is observed that ejecta distribution can be described using power law with crater diameter and depth/ diameter (d/D) ratio. Ejecta behaviour is analysed for both the terrain types, highland and mare, enabling us to understand the effect and dependency of target rock properties on the ejecta characteristics. Further, the d/D dependence has indicated that the relative de-gradation rate appears higher for highland region compared to mare region.Keywords
Lunar Impact Craters, Radar, Spatial Ejecta Emplacement, Target Properties.Full Text
- Morphology of Slope Streaks within Nicholson Crater, Mars:Records of Recent Wind Activity
Abstract Views :214 |
PDF Views:82
Authors
Affiliations
1 PLANEX, Physical Research Laboratory, Ahmedabad 380 009, IN
1 PLANEX, Physical Research Laboratory, Ahmedabad 380 009, IN
Source
Current Science, Vol 114, No 03 (2018), Pagination: 596-607Abstract
Wind is currently the dominant active geological agent bringing about constant changes over the Martian surface. One of the most conspicuous resultant morphology derived is the formation of slope streaks, highly transient features that tend to develop and may completely disappear within a few ten of years. In this article a detailed analysis on the pattern, morphology and appearance of slope streaks within the central mound of the Nicholson crater on Mars, has been made and plausible reasons for their formation as well as darkening and fading mechanisms are discussed. We focus on some observations which indicate the role of wind in carving specific streak patterns. The morphological observations discussed, strongly support active aeolian processes and provide evidences in favour of the dust avalanche theory for the formation and current morphology of slope streaks in the Nicholson crater.Keywords
Aeolian Activities, Craters, Morphology, Slope Streaks.Full Text
References
- Silvestro, S., Fenton, L. K., Vaz, D. A., Bridges, N. T. and Ori, G. G., Ripple migration and dune activity on Mars; evidence for dynamic wind processes. Geophys. Res. Lett., 2010, 37, L20203; doi:10.1029/2010GL044743.
- Silvestro, S. et al., Pervasive aeolian activity along rover Curiosity’s traverse in Gale crater, Mars, Geology, Geological Society of America, 2013; doi:10.1130/G34162.1.
- Zimbelman, J. R., Bourke, M. C. and Lorenz, R. D., Recent developments in planetary aeolian studies and their terrestrial analogs. Aeolian Res., 2013, 11, 109–126.
- Bradley, B. A., Sakimoto, S. E., Frey, H. and Zimbelman, J. R., Medusae Fossae Formation: new perspectives from Mars Global Surveyor. J. Geophys. Res. E, 2002, 107(E8), 2-1–2-17.
- Schorghofer, N. and King, C. M., Sporadic formation of slope streaks on Mars. Icarus, 2011, 216(1), 159–168.
- Fenton, L. K. and Richardson, M. I., Martian surface winds’ insensitivity to orbital changes and implications for aeolian processes. J. Geophys. Res., 2001, 106(El2), 32,885–32,902.
- Fenton, L. K., Bandfield, J. L. and Ward, A. W., Aeolian processes in proctor crater on Mars: sedimentary history as analyzed from multiple data sets. J. Geophys. Res., E, 2003, 108, 1–3.
- Baratoux, D. et al., The role of the wind-transported dust in slope streaks activity: evidence from the HRSC data. Icarus, 2006, 183(1), 30–45.
- Schorghofer, N., Aharonson, O. and Khatiwala, S., Slope streaks on Mars: Correlations with surface properties and the potential role of water. Geophys. Res. Lett., 2002, 29(23), 2126; doi: 10.1029/2002GL015889.
- Bergonio, J. R., Rottas, K. M. and Schorghofer, N., Properties of Martian slope streak populations. Icarus, 2013, 225(1), 194–199.
- Sullivan, R., Thomas, P., Veverka, J., Malin, M. and Edgett, K. S., Mass movement slope streaks imaged by the Mars Orbiter camera. J. Geophys. Res., 2001, 106(E10), 23,607–23,633.
- De Mijolla, G. M., Howe, K. L. and Dixon, J. C., Experimental simulation of Martian slope streak formation. In 42nd Lunar and Planetary Science Conference, The Woodlands, Texas, USA, abstr. # 1142, 7–11 March 2011.
- Head, J. W., Marchant, D. R., Dickson, J. L., Levy, J. S. and Morgan, G. A., Slope streaks in the Antarctic Dry Valleys: characteristics, candidate formation mechanisms, and implications for slope streak formation in the Martian environment. In 10th International Symposium on Antarctic Earth Sciences, U.S. Geological Survey and the National Academies, USGS of 2007-1047 (extended abstr.), 177, 2007.
- Phillips, C. B., Burr, D. M. and Beyer, R. A., Mass movement within a slope streak on Mars. Geophys. Res. Lett., 2007, 34(L21202); doi:10.1029/2007GL031577.
- Morris, E., Aureole deposits of the Martian volcano Olympus Mons. J. Geophys. Res., 1982, 87, 1164–1178.
- Malin, M. C. and Edgett, K. S., Mars Global Surveyor Mars Orbiter camera: interplanetary cruise through primary mission. J. Geophys. Res., 2001, 106, 23,429–23,570.
- Schorghofer, N., Aharonson, O., Gerstell, M. F. and Tatsumi, L., Three decades of slope streak activity on Mars. Icarus, 2007, 191, 132–140.
- Chilton, H. and Phillips, C., Temporal contrast changes in dark slope streak on Mars. In 44th Lunar and Planetary Science Conference, The Woodlands, Texas, USA, Abstr. # 3109, 18–22 March 2013.
- Kreslavsky, M. A. and Head, J. W., Slope streaks on Mars: a new ‘wet’ mechanism. Icarus, 2009, 201, 517–527.
- McEwen, A. S. et al., Mars reconnaissance orbiter’s High Resolution Imaging Science Experiment (HiRISE). J. Geophys. Res., 2007, 112(E05S02), doi:10.1029/2005JE002605.
- Malin, M. C. et al., Context camera investigation on board the Mars reconnaissance orbiter. J. Geophys. Res., 2007, 112; doi:10.1029/2006JE002808.
- Silvestro, S., Vaz, D. A., Fenton, L. K. and Geissler, P. E., Active aeolian processes on Mars: a regional study on Arabia and Meridiani Terrae. Geophys. Res. Lett., 2011, 38(L20201).
- Rice, M. S., Bell, J. F. III, Gupta, S., Warner, N. H., Goddard, K. and Anderson, R. B., A detailed geologic characterization of Eberswalde crater, Mars. Int. J. Mars Sci. Expl., Mars Inform., (open access journals), 2005; doi:10.1555/mars.2005.1.0.
- Goudie, A. S., Arid and Semi-Arid Morphology, Aeolian Geomorphology, Cambridge University Press, 2013, pp. 156–157.
- Gerstell, M. F., Aharonson, O. and Schorghofer, N., A distinct class of avalanche scars on Mars. Icarus, 2004, 168, 122–130.
- Chaung, F. C., Beyer, R. A., McEwen, A. S. and Thompson, B. J., HiRISE observations of slope streaks on Mars. Geophys. Res. Lett., 2007, 34(20); doi:10.1029/2007GL031111/
- Miyamoto, H., Dohm, J. M., Beyer, R. A. and Baker, V. R., Fluid dynamical implications of anastamosing slope streaks on Mars. J. Geophys. Res., 2004, 109(E06008); doi:10.1029/2003JE002234.
- Aharonson, O., Schorghofer, N. and Gerstell, M. F., Slope streak formation and dust deposition rates on Mars. J. Geophys. Res., 2003, 108(E12), 5138; doi:10.1029/2003JE002123.
- Ferguson, H. M. and Lucchitta, B. K., Dark streaks on talus slopes, Mars, In Reports of the Planetary Geology Program, NASA Technical Memoir, TM-86246, pp. 188–190 (1983, 84).
- Williams, S. H., Dark talus streaks on Mars are similar to aeolian dark streaks. In Lunar and Planetary Science XXII, Houston, USA, abstr. #1509, 18–22 March 1991.
- Ferris, J. C., Dohm, J. M., Baker, V. R. and Maddock, T. III, Dark slope streaks on Mars: are aqueous processes involved? Geophys. Res. Lett., 2002, 29(10), 128-1–128-4.
- Motazedian, T., Currently flowing water on Mars. In Lunar and Planetary Science, Houston, USA, 2003, vol. XXXIV, abstr. #1840.
- Burleigh, K. J., Melosh, H. J., Tornabene, L. L., Ivanov, B., McEwen, A. S. and Daubar, I. J., Impact airblast triggers dust avalanches on Mars. Icarus, 2012, 217, 194–201.