Correlation Between Graben Orientation, Channel Direction Change, and Tectonic Loading: The Elysium Province, Mars. Issue 3 (1st March 2019)

• Record Type: Journal Article
• Authors: Kneller, B. D.; Roberts, G. P.; Grindrod, P. M.
• Is Part Of: Journal of geophysical research. Volume 124:Issue 3(2019)
• Page Start: 652
• Page End: 680
• Publication Date: 2019-03-01
• Subjects: tectonics -- volcanism -- Rille -- channel -- FEM; Planets -- Periodicals; Geophysics -- Periodicals; 559.9
• DOI: 10.1029/2018JE005795
• Languages: English
• ISSNs: 2169-9097

Abstract

Abstract: We have investigated the links between regional stress fields, the volcanic centers, rifts, graben, and channels in the NW region of the Elysium Province (Figures 1 a and1 b) to determine whether the sequence of stress events occurring during province development can be derived from the morphologies of these features, and thus provide a sequence of development events, which is independent of surface dating techniques. Rift and graben geomorphology was mapped, and the neighboring relationships and orientation of individual graben were assessed to determine any spatial clustering or preferred orientation with regional or surface features capable of creating lithospheric flexure or tectonic stress within the study area. Crosscutting analysis determined a time ordered sequence of graben formation and these were related to volcanic centers or regional sources of stress. In addition, mapping showed that different channels share sections with similar shape and orientation, prompting our study of whether these channels, in tandem with the graben, were tectonically influenced during their development. The channel central axes were mapped and compared to identify common sequences of channel direction change. The time sequence of channel direction changes and the time‐ordered sequence of graben development were then compared. We have demonstrated a correlation between rift and graben direction with channel orientation suggesting a regional stress control from evolving volcanic centers. Overall we derive, for the first time, the temporal pattern of tectonic, volcanic, and channel evolution for the northwestern region of this major magmatic province on Mars. Plain Language Summary: The northwest region of the Elysium Volcanic Province includes volcanoes, large outflow channels, and narrow straight valleys called graben. We noticed that some outflow channel shapes matched, and nearly all graben were arranged in lines, curves, or clusters. Analyzing these arrangements we identified a sequence of geological events that could have created the province. With mapping and analysis we have shown that the outflow channel directions, and the location and direction of graben, have been controlled by the same tectonic forces. As events changed in time the force direction also changed, allowing us to identify probable events, for example volcano growth. We suggest that the Province elevation increased as magma rose from the Martian interior; then the Hecates Tholus volcano increased in size, followed by the growth of Elysium Mons, the largest volcano in the Province. We suggest that some lava erupted by Elysium Mons flowed away in subsurface channels called dikes to the surrounding Province, creating graben similar to some features seen in the northern Canadian Shield. These results are important since this is the first time the Province growth events have been measured in this way, and the results are more accurate than some earlier attempts to predict this history. Key Points: Graben are systematically arranged around sources of volcanically, generated stress, lithospheric loading, or regional stress A common sequence of region wide stress events that correlate with graben direction and orientation of channels of differing morphology A development sequence for the NW Elysium Province is proposed using graben orientation and channel direction analysis