A multidisciplinary approach involvin
g various remote sensin
g instruments is used to investi
gate
Apollinaris Mons, a prominent volcano on Mars, as well as the surroundin
g plains for si
gns of prolon
ged hydrolo
gic and volcanic, and possibly hydrothermal activity. The main findin
gs include (1) evidence from laser altimetry indicatin
g the lar
ge thickness (1.5-2 km at some locations) of the fan deposits drapin
g the southern flank contrary to previous estimates, coupled with possible layerin
g which point to a si
gnificant emplacement phase at Apollinaris Mons, (2) corroboration of Robinson et al. (Robinson, M.S., Mou
ginis-Mark, P.J., Zimbelman, J.R., Wu, S.S.C., Ablin, K.K., Howin
gton-Kraus, A.E. [1993]. Icarus 104, 301-323) hypothesis re
gardin
g the formation of incised valleys on the western flanks by density current erosion which would indicate ma
gma-water interaction or, alternatively, volatile-rich ma
gmas early in the volcano¡¯s history, (3) mounds of diverse
geometric shapes, many of which display summit depressions and occur amon
g faults and fractures, possibly markin
g ventin
g, (4) stron
g indicators on the flanks of the volcano for lahar events, and possibly, a caldera lake, (5) ubiquitous presence of impact craters displayin
g fluidized ejecta in both shield-formin
g (flank and caldera) materials and materials that surround the volcano that are indicative of water-rich tar
get materials at the time of impact, (6) lon
g-term complex association in time amon
g shield-formin
g materials and Medusae Fossae Formation.
The findings point to a site of extensive volcanic and hydrologic activity with possibly a period of magma-water interaction and hydrothermal activity. Finally, we propose that the mound structures around Apollinaris should be prime targets for further in situ exploration and search for possible exobiological signatures.