Elysium planitia, mars: Regional geology, volcanology, and evidence for volcano-ground ice interactions

Abstract

Geological mapping of Elysium Planitia has led to the recognition of five major surface units, in addition to the three volcanic constructs Elysium Mans, Hecates Tholus, and AIbor ThoIus. These units are interpreted to be both volcanic and sedimentary or erosional in origin. The volcano Elysium Mons is seen to have dominated constructional activity within the whole region, erupting lava flows which extend up to 600 km from the summit. A major vent system, covering an area in excess of 75 000 km*, is identified within the Elysium Fossae area. Forty-one sinuous channels are visible within Elysium Planitia; these channels are thought to be analogous to lunar sinuous rilIes and their formation in this region of Mars is attributed to unusually high regional topographic slopes (up to -1.7"). Numerous circumferential graben are centered upon Elysium Mons. These graben, located at radial distances of 175, 205-225, and 330 km from the summit, evidently postdated the emplacement of the Elysium Mons lava flows but pre-dated the eruption of extensive flood lavas to the west of the volcano. A great diversity of channel types is observed within Elysium Fossae. The occurrences of streamlined islands and multiple floor-levels within some channels suggests a fluvial origin. Conversely, the sinuosity and enlarged source craters of other channels suggests a volcanic origin. Impact crater morphology, the occurrence of chaotic terrain, probable pyroclastic deposits upon Hecates Tholus and fluvial channels all suggest extensive volcano-ground ice interactions within this area.

Arecibo radar imagery of Mars: The major volcanic provinces

“…Mouginis-Mark et al (1984) claimed this feature to be a lobe of young flood lavas, which would be consistent with its smoothness in the MOLA roughness map (Fig. 18b).…”

“…19). Elysium Mons (19-A), the largest and marginally youngest of the three volcanoes, is the source of most of the extended lava flows in the region (Mouginis- Mark et al, 1984;Greeley and Guest, 1987;Hodges and Moore, 1994). It is also the only Elysium volcano to show an extensive radar-bright feature.…”

The Evolution of the Martian Hydrosphere: Implications for the Fate of a Primordial Ocean and the Current State of the Northern Plains

“…This possibility was first suggested by Masursky et al (1977) and has recently been raised again by McKenzei and Nimmo (1999), who argue that an episode of intense volcanic activity, centered on Tharsis, may have triggered a massive regional melting of ground ice that resulted in the hydrothermally driven and structurally controlled discharge of groundwater to the surface. While local igneous activity has almost certainly played a role in the origin of some outflow channels-such as those located to the west of Elysium Mons (Mouginis-Mark et al 1984, Brandstrom 1986) and south of Hadriaca Patera Greeley 1993, Squyres et al 1987)-there are a number of serious volumetric problems with invoking this same mechanism to explain the majority of circum-Chryse channels.…”

An Investigation of the Hypotheses for Formation of the Platy-Ridged-Polygonized Terrain in Elysium Planitia, Mars

“…The discovery of geologically young (late Amazonian age) Platy-Ridged-Polygonized (PRP) terrain in Elysium Planitia, Mars can be traced back to earlier geologic mapping from the Viking images (Mouginis-Mark et al, 1984;Tanaka, 1986). However, the detailed morphology and structure of the PRP terrain could be studied only recently with high resolution images.…”

“…In early geologic mapping, the PRP terrain in Elysium Planitia, Mars was considered a water-formed landform based on the morphologies (Mouginis-Mark et al, 1984;Tanaka, 1986). The hypothesis was strengthened in subsequent regional studies by the discovery of small channels, and the water was supposed to have arisen from the interaction between volcanic flows and ice on Mars (Scott and Chapman, 1991;Edgett and Rice, 1995).…”