Resumen: Claritas rise is a prominent ancient (Noachian) center of tectonism identified through investigation of
comprehensive paleotectonic information of the
western hemisphere of Mars. This center is interpreted to
be the result of magmatic-driven activity, including uplift and associated tectonism, as well as possible
hydrothermal activity. Coupled with its ancient stratigraphy, high density of impact craters, and complex
structure, a possible magnetic signature may indicate that it formed during an ancient period of Mars'
evolution, such as when the dynamo was in operation. As Tharsis lacks magnetic signatures, Claritas rise may
pre-date the development of Tharsis or mark incipient development, since some of the crustal materials
underlying Tharsis and older parts of the magmatic complex, respectively, could have been highly resurfaced,
destroying any remanent magnetism. Here, we detail the significant characteristics of the Claritas rise,
and present a case for why it should be targeted by the Mars Odyssey, Mars Reconnaissance Orbiter, and Mars
Express spacecrafts, as well as be considered as a prime target for future tier-scalable robotic reconnaissance.
Resumen: Throughout the recorded history of Mars, liquid water has distinctly shaped its landscape, including the prominent circum-Chryse and the
northwestern slope valleys outflow channel systems, and the extremely flat northern plains topography at the distal reaches of these outflow
channel
systems. Paleotopographic reconstructions of the Tharsis magmatic complex reveal the existence of an Europe-sized Noachian
drainage basin and subsequent aquifer system in eastern Tharsis. This basin is proposed to have sourced outburst floodwaters that sculpted the
outflow channels, and ponded to form various hypothesized oceans, seas, and lakes episodically through time. These floodwaters decreased
in volume with time due to inadequate groundwater recharge of the Tharsis aquifer system. Martian topography, as observed from the Mars
Orbiter Laser Altimeter, corresponds well to these ancient flood inundations, including the approximated shorelines that have been proposed
for the northern plains. Stratigraphy, geomorphology, and topography record at least one great Noachian-Early Hesperian northern plains
ocean, a Late Hesperian sea inset within the margin of the high water marks of the previous ocean, and a number of widely distributed
minor lakes that may represent a reduced Late Hesperian sea, or ponded waters in the deepest reaches of the northern plains related to minor
Tharsis- and Elysium-induced Amazonian flooding.
Resumen: The Gamma Ray Spectrometer (Mars Odyssey spacecraft) has revealed
elemental distributions of
potassium (K), thorium(Th), and iron (Fe) on Mars that require fractionation of K (and possibly Th and
Fe) consistent with aqueous activity. This includes weathering, evolution of soils, and transport, sorting,
and deposition, as well as with the location of first-order geomorphological demarcations identified as
possible paleoocean boundaries. The element abundances occur in patterns consistent with weathering
in situ and possible presence of relictor exhumed paleosols, deposition of weathered materials (salts
and clastic minerals), and weathering/transport under neutral to acidic brines. The abundances are
explained by hydrogeology consistent with the possibly over lapping alternatives of paleooceans and/or
heterogeneous rock compositions from diverse provenances (e.g., differing igneous compositions).
Resumen: In this paper, we show that the complex geological evolution of Valles Marineris, Mars, has been highly
influenced by the manifestation
of magmatism (e.g., possible plume activity). This is based on a diversity of
evidence, reported here, for the central part, Melas Chasma, and nearby regions, including uplift, loss of huge
volumes of material, flexure, volcanism, and possible hydrothermal and endogenic-induced outflow channel
activity. Observations include: (1) the identification of a new N50 km-diameter caldera/vent-like feature on
the southwest flank of Melas, which is spatially associated with a previously identified center of tectonic
activity using Viking data; (2) a prominent topographic rise at the central part of Valles Marineris, which
includes Melas Chasma, interpreted to mark an uplift, consistent with faults that are radial and concentric
about it; (3) HiRISE-identified landforms along the floor of the southeast part of Melas Chasma that are
interpreted to reveal a volcanic field; (4) CRISM identification of sulfate-rich outcrops, which could be
indicative of hydrothermal deposits; (5) GRS K/Th signature interpreted as water–magma interactions and/
or variations in rock composition; and (6) geophysical evidence that may indicate partial compensation of
the canyon and/or higher density intrusives beneath it. Long-term magma, tectonic, and water interactions
(Late Noachian into the Amazonian), albeit intermittent, point to an elevated life potential, and thus Valles
Marineris is considered a prime target for future life detection missions.
