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_Journal of Structural Geology 32 (2010) 855–875_ _Contents lists available at ScienceDirect_ _Journal of Structural Geology_ _journal homepage: www.elsevier.com locate jsg_ _Review Article_ _Interpretation and analysis of planetary structures_ _Richard A. Schultz a,*, Ernst Hauber b, Simon A. Kattenhorn c, Chris H. Okubo d, Thomas R. Watterse a Geomechanics-Rock Fracture Group, Department of Geological Sciences and Engineering 172, University of Nevada, Reno, NV 89557-0138, United States b DLR-Institut für Planetenforschung, Rutherfordstrasse 2, D-12489 Berlin-Adlershof, Germany c Department of Geological Sciences, University of Idaho, P.O. Box 443022, Moscow, ID 83844-3022, United States d U.S. Geological Survey, 2255 North Gemini Drive, Flagstaff, AZ 86001, United States e Center for Earth and Planetary Studies, National Air and Space Museum, Smithsonian Institution, Washington, DC 20560, United States_ _article info_ _Article history: Received 24 April 2009 Received in revised form 31 August 2009 Accepted 13 September 2009 Available online 11 December 2009_ _Keywords: Planetary structural geology Faulting Folding Deformation bands Joints Fracture mechanics_ _abstract_ _Structural geology is an integral part of planetary science. Planetary structures provide the framework for determining the character and sequence of crustal deformation while simultaneously establishing the observational basis required to test geodynamic hypotheses for the deformation of planetary and satellite lithospheres. The availability of datasets that record spatial and topographic information with a resolution that matches or, in many cases, exceeds what is available for Earth-based studies permits the deformation of several planets and satellites to be investigated down to the local or outcrop scales. The geometry and kinematics of common planetary structures such as joints, igneous dikes, deformation bands, faults, and folds can be determined with confidence from their distinctive morphologic and topographic signatures, enabling the structural histories and deformation magnitudes to be determined. Segmentation, displacement profiles, relay ramps, footwall anticlines, displacement-controlled depocenters, and other well-known characteristics of terrestrial normal fault and graben systems reveal the sequence and processes of fault growth in numerous planetary examples. Systems of thrust faults having both blind and surface-breaking components are important elements on several bodies including Mercury, the Moon, and Mars. Strike-slip faults have been identified on bodies including Mars and Europa with oblique extension found on Ganymede. Using field-based studies of Earth-based structures as a guide, planetary structures provide a means to explore and evaluate the causative stresses. Despite the wide range in structural styles across the solar system, plate tectonics is recognized only on Earth, with the other planets and satellites deforming in the absence of large-scale horizontal motions and attendant plate recycling._ _© 2010 Elsevier Ltd. All rights reserved._ _1. Introduction_ _Deformation of the lithospheres of planets and satellites has produced populations of structures that appear to be strikingly similar to those found on Earth (see Watters and Schultz, 2010, for a comprehensive overview), both morphologically and mechanically. Faults in particular have been documented on nearly every geologic surface in the solar system, occurring in both lower-strain distributed and higher-strain localized regimes. Normal faults and grabens are found on Mercury, Venus, the Moon, Mars, and icy satellites of the outer planets such as Europa, Ganymede, Miranda, Ariel, Dione, Tethys, Rhea, and Titania (e.g., Watters and Schultz, 2010). Thrust faults have been recognized on Mercury, Venus, the Moon, Mars, and Io along with their surface-breaking components called wrinkle ridges (Plescia and Golombek, 1986; Watters, 1988; Schenk et al., 1994; Schultz, 2000a; Okubo and Schultz, 2004). Arcuate fold belts related to contractional strain have been identified in the icy lithospheric shell of Enceladus (Porco et al., 2006), and rare folding has also been inferred on Europa (Prockter and Pappalardo, 2000). Strike-slip faults have been identified on Mars (e.g., Schultz, 1989; Okubo and Schultz, 2006a; Andrews-Hanna et al., 2008) and the icy satellites Europa (Schenk and McKinnon, 1989; Hoppa et al., 1999a; Kattenhorn, 2004; Kattenhorn and Marshall, 2006) and Ganymede (in association with normal faulting; DeRemer and Pappalardo, 2003; Pappalardo and Collins, 2005). Individual dilatant cracks (joints; Schultz and Fossen, 2008) have been identified on Mars (Okubo and McEwen, 2007; Okubo et al., 2009) and are pervasive on icy moons of the outer solar system such as Europa (Figueredo and Greeley, 2000, 2004; Kattenhorn, 2002; Marshall and Kattenhorn, 2005) and Enceladus (Kargel and Pozio, 1996; Porco et al., 2006). Deformation bands (Aydin et al., 2006; Fossen et al., 2007) have been identified on Mars (Okubo and McEwen, 2007; Okubo et al., 2009) and have been suggested to occur on Europa (Aydin, 2006). The presence of subsurface igneous dikes has been inferred on Mars from surface topographic data (Schultz et al., 2004) and, in this paper, identified there in high-resolution imaging data._ _In this paper we gather and present some of the findings from recent spacecraft exploration of the solid-surface planets and satellites in our solar system (see Beatty et al. (1999) for general information on the planets and satellites in our solar system). Following current usage, terrestrial planets are bodies having solid silicate crusts and include Mercury, Venus, Earth, Earth’s Moon, and Mars. Icy satellites are those whose crusts are primarily composed of ices of water, methane, and ammonia and include most of the satellites of Jupiter, Saturn, Uranus and Neptune. For brevity we refer the reader to McGill et al. (2010) for the structural geology of Venus and to Collins et al. (2010) for studies of faulting and deformation of Ganymede, Callisto, and Io. We also do not discuss the rather extensive literature on the structural geology of terrestrial impact craters (see Earth Impact Database, 2007) despite its importance to the understanding of deformation processes on the Earth and other planets (e.g., Laney and Van Schmus, 1978; Price and Cosgrove, 1990, pp. 112–118; Kriens et al., 1999; Huntoon, 2000; Kenkmann, 2002; Kenkmann et al., 2005; Pati and Reimold, 2007)._ _First we describe the principal types of data, such as imaging or topography, that are being used to identify and interpret planetary structures (i.e., on planets and satellites other than the Earth). Next, we present a suite of results from the geologic mapping and analysis of structures such as faults, folds, joints, and igneous dikes on bodies as diverse and complex as Mercury, the Moon, Mars, and icy satellites of Jupiter. Last, we explore two avenues that these structures can provide into the mechanics of deformation on these bodies. The overall theme of this paper is to demonstrate that structural geology should not be considered to be restricted to the Earth, and that by studying other bodies with different geodynamic styles we can learn about the response of lithospheres to a variety of stress states having different origins._ _2. Data sets_ _Several types of data are available to permit the identification and analysis of planetary geologic structures. As discussed for example by Tanaka et al. (2010), these include imaging (using visible, near-infrared, and radar wavelengths) and topography, both having various resolutions and degrees of coverage depending on the planetary body of interest. The principal data sets currently being used in planetary structural geology are described in this section, organized by planet or satellite. Radar-based imaging systems that have been used on Venus and Titan are discussed by McGill et al. (2010) and Tanaka et al. (2010), respectively. Planetary data from NASA and European Space Agency (ESA) missions are publicly available through NASA’s Planetary Data System (http://pds.jpl.nasa.gov) and its European node, Planetary Science Archive (http://www.rssd.esa.int/index.php?project=PSA)._ _2.1. Mercury_ _Until recently, the only spacecraft to observe Mercury was Mariner 10, which imaged about 45% of the planet’s surface during three flybys in 1974 and 1975. Many Mariner 10 images (having an average spatial resolution of 1 km) were comparable in resolution to Earth-based telescope observations of the Moon. Currently, the MESSENGER spacecraft en-route to Mercury (Solomon et al., 2007) has completed three flybys and has returned a wealth of new imaging, topographic, and geophysical data from the planet (see Solomon et al., 2008 for some of the initial findings). Once the spacecraft enters orbit, MESSENGER’s Mercury Dual Imaging System (MDIS) will provide a 250-m per pixel or better global mosaic, and the planet’s topography will be measured by the Mercury Laser Altimeter (MLA) instrument and using digital elevation models derived from stereo images (Solomon et al., 2007, 2008)._ _2.2. Moon_ _Several current and forthcoming datasets will complement the high-quality imaging datasets acquired during the Apollo era of the 1960s to early 1970s (e.g., Schultz, 1976; Masursky et al., 1978) including Lunar Orbiter and Apollo metric and panoramic camera images (Tanaka et al., 2010) and images and data returned more recently by the Clementine and Lunar Prospector missions. The Lunar Reconnaissance Orbiter (LRO; Chin et al., 2007) has a suite of science instruments, two of which will be especially useful for investigating geologic structures. The Lunar Reconnaissance Orbiter Camera (LROC) will provide high-resolution imaging data, while the Diviner Lunar Radiometer Experiment (DLRE) will measure surface temperatures and help identify thermal anomalies indicative of geological features such as impact craters or volcanic vents._ Ключевые слова: dike, terrestrial, global, ridge, data returned, cambridge, tectonic process, martian, planetary surface, strike-slip faulting, image, offset, tectonic, orbital eccentricity, data, cambridge university, university press, graben, galileo mosaic, global contraction, outcrop scale, doi, chasma, topographic, spacecraft, relationship, geophysical doi, nimmo, science, segment, impact, head, vertical offset, resolution, eds, terrestrial grabens, journal geophysical doi, europa, geologic evolution, geological, surface, strike-slip fault, icy, thrust fault, lateral offset, geologic mapping, implication, tectonics, offset feature, measured, normalized separation, morphologic element, south-polar region, aydin, fracture, geophysical, university, study, pollard, evidence, anderson, length, planetary, candor, exponential function, satellite, normal fault, shell, mapped fault, relative age, letters, structure, rock, strike-slip, maximum displacement, geologic structure, fracture aperture, earth, york, mare basalt, structural, thrust, stereo image, displacement-length relationship, fracture mechanics, hauber, crack, geophysical letters, pappalardo, topography, far-eld stress, grabens, scaling relation, lobate scarp, northeastern ank, geology, normal, tectonic evolution, journal geophysical, process, collins, mars, mechanical, cambridge university press, vertical resolution, structural geology, failure mode, basin, rift, crosscutting relationship, deformation, geologic, martian surface, stress, layered deposit, golombek, mckinnon, displacement, area, press, swath width, global mapping, martian fault, displacement prole, joint, opening-mode fracture, schultz, endogenic process, mcewen, hlisch, ice, displacement-length scaling, tectonic landforms, mcgill, wrinkle ridge, mechanics, ice shell, hrsc, greenberg, fold, causative stress, planetary structure, atkinson, mapping, border fault, chasma-related rifting, structural attitude, contractional strain, surface load, mechanical property, igneous dike, ha, stress history, phillips, strom, surface albedo, mpa olson, galilean satellite, watters, tectonic pattern, lucchitta, geologic history, polar wander, structural orientation, solomon, schenk, matching feature, planet, fault scarp, mechanical interaction, fault population, layer, perspective view, kattenhorn, scale, heat, lithospheric thickness, layered, journal structural, moon, okubo, crustal deformation, structural history, scarp, imaging, rembrandt basin, relief arch, nature, opening displacement, structural study, candor chasma, tectonic history, analysis, icarus, martian grabens, enceladus, icy satellite, dzurisin melosh, schultz journal, mercury, hirise, pixel, faulting, model, me ge, complex pattern, lunar, spatial resolution, chapman, impact crater, band, history, relay ramp, sharp cusp, icy moon, journal structural geology, fault, journal, structural evolution, rock mechanics, fossen, individual fault, displacement proles, scaling, observed, deposit, fault segment