Geology of the Uranius Group Volcanic Constructs: Uranius Patera, Ceraunius Tholus, and Uranius Tholus

Arecibo radar imagery of Mars: The major volcanic provinces

“…The smallest of these shields, Uranius Tholus (14-L), is radar-dark. This is consistent with the lack of well-defined lava flows and indications that much of the shield is mantled, possibly with pyroclastic deposits (Plescia, 2000). Ceraunius Tholus (14-M) is also mostly lacking in recognizable lava flows and may also be pyroclastically mantled (Plescia, 2000).…”

“…The west flank of the shield is completely radar-dark. This side of the shield has a smooth appearance and is probably the youngest surface on Ceraunius (Crumpler et al, 1996;Plescia, 2000). Crumpler et al suggest the west flank is pyroclastically mantled, which would be consistent with its radar darkness.…”

“…These Uranius Patera features show up even better in the inset figure at upper right in Fig. 14, which shows a radar image from February 2012 (when the volcano was imaged at a much smaller incidence angle). Uranius Patera shows more effusive flow features and less pyroclastic mantling than its two neighboring shields (Plescia, 2000), which could explain some of the radar brightness. Why its southwest flank flows should be rougher than elsewhere on the shield is not clear, however, nor are there any distinguishing morphologic features on this side of the volcano (except for a narrow trough).…”

Tharsis Tholus: an unusual martian volcano

“…Figure 7a shows one on the northern flank The morphologic attributes of the trough, such as a single channel of uniform width, levees, lack of tributaries, and restricted occurrence, are more suggestive of a volcanic than a fluvial origin. However, many of the channels on Ceraunius Tholus (Plescia, 2000) have morphologies similar to those on Tharsis Tholus, and the Ceraunius troughs have been interpreted as fluvial in origin (Gulick, 2001).…”

“…In addition to the large structures, there are countless low shields hundreds of meters high and several to tens of kilometers wide (e.g., Sakimoto et al, 2003;Hiesinger and Head, 2002). Aspects of Tharsis volcanism have been studied by many investigators and most of the constructs have been the subject of specific investigations (e.g., Crumpler and Aubele, 1978;Greeley and Spudis, 1981;Cattermole, 1990;Hodges and Moore, 1994;Morris and Tanaka, 1994;Plescia, 1994Plescia, , 2000Scott and Zimbelman, 1995;Scott et al, 1998).…”