Crustal extension in the Ceraunius Fossae, Northern Tharsis Region, Mars

Abstract

[1] We investigated the Ceraunius Fossae area, Northern Tharsis, in order to obtain quantitative information on the tectonic extension affecting this area. Tectonic structures of the Ceraunius Fossae area have been previously described using Viking images and interpreted as extensional structures. Laser altimetry data (MOLA) can be used to quantitatively investigate these structures with a better resolution. We developed a method to obtain E-W oriented profiles (perpendicular to the main tectonic structures) with a sufficiently high resolution to analyze tectonic structures in spite of the low data density in this direction. We interpreted all the recognizable extensional structures along the profiles, and using a simplified structural model, we estimated tectonic extension along these transects. The extension calculated over the entire profiles is 36 km (e 24 = (l 1 À l 0 )/l 0 = (910 km À 874 km)/874 km = 0.041) and 42 km (e 26 = (730 km À 688 km)/688 km = 0.061) along profile 24 and profile 26, respectively. In the most deformed area, extension reaches the value of 22 km (e max = (l 1 À l 0 )/l 0 = (186 km À 164 km)/164 km = 0.134). Since the extension accounted by the topographic doming is negligible, a significant horizontal crustal motion is required to explain the observed extension.

Oblique rifting at Tempe Fossae, Mars

“…From the pioneer works of Carr [1974], Wise et al [1979], and Melosh [1980], tectonic structures on the Tharsis dome have been extensively studied. Some highlights of this intense scrutiny are the identification of several episodes of tectonism [ Plescia and Saunders , 1982], the publishing of Tharsis paleotectonic maps [ Scott and Dohm , 1990], the mapping of stress fields [ Tanaka et al , 1991], the hypothesis of nonhydrostatical stresses to account for the contractive deformation [ Watters , 1993], countered by Banerdt and Golombek [2000], who attributed the deformation to flexure alone, the tentative reconstruction of tectonic stages by Anderson et al [2001], and the in‐depth regional studies of Hauber and Kronberg [2001] at Tempe Fossae, Cailleau et al [2003] at Alba Patera, Wilkins and Schultz [2003] at Valles Marineris, or Borraccini et al [2005] at Ceraunius Fossae.…”

“…This tectonic transport would explain a number of important transcurrent and thrusting structures, including some rhomb‐horst alignments indicative of local transpressional tectonics. On the other side, Borraccini et al [2005] concluded that a significant horizontal crustal motion was needed to explain Ceraunius Fossae, a set of graben near the Tharsis center. The contrast between “load” and “thrust” hypotheses has been increasing as the investigations on Tharsis’ structure accumulated.…”

Arecibo radar imagery of Mars: The major volcanic provinces

“…Scott and Tanaka (1986) map the east wing of the CFF as extending beyond the northern and eastern limits of the radar-bright feature. However, the revised mapping by Tanaka (1990) redesignates this region as late-Hesperian and shrinks the NE boundaries of the CFF into much better agreement with the boundaries of the radar feature (see also Borraccini et al, 2005Borraccini et al, , 2006. The map of Scott and Tanaka (1986) also shows the CFF extending below 20°N latitude into the region east of the Jovis Tholus shield (7-V).…”

“…The eponymous Ceraunius Fossae (or CF) comprises three lobes of fractured terra of late-Noachian to early-Hesperian age that are characterized by dense clusterings of N/S-aligned graben (Scott and Tanaka, 1986;Tanaka, 1990;Borraccini et al, 2005Borraccini et al, , 2006. The CF rises above, and is embayed, by the younger CFF flows.…”

An episodic slab-rollback model for the origin of the Tharsis rise on Mars: Implications for initiation of local plate subduction and final unification of a kinematically linked global plate-tectonic network on Earth

“…The graben zone passes through the Tharsis rise diagonally, cutting through Alba Patera, Ceraunius Fossae, the Local subduction and fi nal unifi cation of a global plate-tectonic network | RESEARCH Tharsis Montes, and Claritas Fossae (Figs. 2, 3, and 4; e.g., Scott and Tanaka, 1986;Borraccini et al, 2005;Hauber and Kronberg, 2005;Carr, 2006;Dohm et al, 2009b). Individual grabens are expressed by closely spaced topographic depressions either bounded by normal faults or underlain by dikes (e.g., Anderson et al, 2001;Wyrick et al, 2004;Schultz et al, 2006Schultz et al, , 2008Polit et al, 2009;Wilson and Head, 2002;Scott et al, 2002;Wyrick and Smart, 2009).…”