1.0 Objectives and expected significance The Tharsis Montes (Arsia Mons, Pavonis Mons, and Ascraeus Mons) are three large shield volcanoes, forming a NE-SW-trending chain across the Tharsis rise [Carr et al., 1977; Crumpler and Aubele, 1978]. Their location and recent eruptive activity coincide with the youngest major magmatic and tectonic phase of the Tharsis province [Plescia and Saunders, 1979, 1982; Mege and Masson, 1996; Anderson et al., 2001; Wilson and Head, 2002; Werner, 2005], although the evolution of the shields and their relationship to the province is not well understood. However, the latest generation of Mars spacecraft is producing high-resolution images that are enabling new insights into the geological evolution of these volcanoes via geologic mapping. Geologic maps are critical tools required to relate spacecraft observations of a region to its geologic history, the results of which can provide crucial information that can be used to refine models of geologic processes. We began a systematic program of geologic mapping of the large Tharsis volcanoes, beginning with Olympus Mons (map soon to be submitted) and Arsia and Pavonis Montes (mapping in progress), including characterizing their surface features and their distribution in time and space, which is essential for identifying any changes in the volcanic and gradational processes working within and on these volcanoes. With this proposal we wish to complete our program by geologic mapping of Ascraeus Mons, the only Tharsis Montes volcano for which a 1:1M map has not been previously published [cf., Scott and Zimbelman, 1995; Scott et al., 1998]. The general scientific objective of this proposal is to investigate the volcanic, gradational, and tectonic processes that have formed Ascraeus Mons and its southerly small vent field, using established geologic mapping techniques. We will use Mars Reconnaissance Orbiter (MRO) Context Camera (CTX: Malin et al., 2007) and Mars Express (MEX) High Resolution Stereo Camera (HRSC: Neukum et al., 2004a) data that are geometrically rectified to Mars Global Surveyor (MGS) Mars Orbiter Laser Altimeter (MOLA: Smith et al., 1999; 2001) data as the primary map base. These data will be supplemented by MGS Mars Orbiter Camera (MOC: Malin et al., 1992; Malin and Edgett, 2001), Mars Odyssey (MO) Thermal Emission Imaging System (THEMIS: Christensen et al., 2004), and MRO High Resolution Imaging Science Experiment (HiRISE: McEwen et al., 2007) images. HRSC and CTX have complete coverage of Ascraeus Mons, enabling consistent mapping across the shield. All of the data required for this project are available in the PDS. We will produce a digital geologic map and geomorphologic map, linking them with our maps for both Arsia and Pavonis Montes, all to be published through the USGS. The specific scientific objectives of this mapping project include: 1) Determining the areal extent, distribution, and age relationships of different lava flow morphologies on the main flank, rift apron, and associated small-vent field of Ascraeus Mons to identify and understand changes in effusive style across the volcano, and to provide insight into martian magma production rates. Results, when linked with those of the other Tharsis Montes, will provide insight into the overall volcanic evolution of each structure, enable comparisons between volcanoes, and determine the extent of each shields contribution to the Tharsis plains; 2) Determining the areal extent and distribution of purported glacial and aeolian deposits on the flank and their relationship to the lava flows. Results will establish a volcano-wide understanding of the nature of potential lava-ice interactions and the contribution of aeolian cover to the current form of the shield, enabling comparison among the Tharsis Montes potentially in different stages of development; 3) Characterizing erosional and tectonic features, such as rift zone graben, flank terraces, and channel networks, present on the flank, rift apron, and small-vent field, to determine their relationships to volcanic materials and processes. We will accomplish our objectives using standard techniques of planetary geologic mapping applied to recently available CTX and HRSC images as our main image base. These data cover large areas at consistent resolution, and when supplemented by HiRISE, MOC and THEMIS images enable improved morphological interpretations. The products of this research will be a digital map for Ascraeus Mons, published online by the USGS, at a scale of 1:1,000,000 (1:1M). The results of this research will make possible a more complete understanding of the geologic processes that have formed and modified the Tharsis Montes, with an emphasis on understanding the late-stage effusive history of volcanic activity, and the potential release and interaction with surface volatiles. These results will provide additional insight into understanding the overall evolution of the Tharsis province on Mars. Thus, this research is directly relevant to NASA Strategic Goal #3.3 in understanding the genesis and evolution of Solar System bodies and physical processes active on the terrestrial planets, and MDAP goals of enhancing the scientific return from current Mars missions.
|Effective start/end date||9/1/14 → 8/31/18|
- NASA: Goddard Space Flight Center: $247,292.00