Outputs of the 3D geo-modeling of the layered unit inside Crommelin crater (Mars). This model is based on morphostratigaphic mapping explicit modeling approach. The package contains the basemaps and geo-modeled meshes.
Abstract Deltas have long been considered a constraining element to reconstruct the water level of an ancient ocean that may have once occupied the northern lowlands of Mars, and recently this hypothesis started to be challenged. We investigate this hypothesis and present a global inventory of fan‐shaped features showing typical deltaic traits across the entire Martian surface. For each element, we provide descriptive details and classifications based on morphology, location, and relation with characterizing environmental features. In this catalog of 161 deltas, we identified only six having high potential to constrain an oceanic paleoshoreline. Nonetheless, age and location of these candidates display discrepancies with what was previously suggested from independent data sets about shoreline age and locations. Our analyses hence indicate that deltas alone are insufficient to delineate a globally consistent ancient oceanic shoreline, but they have the potential to locally constrain the water level both in space and time.
<p>The presence of delta deposits on Mars has been thoroughly demonstrated for decades and large scale mapping [1,2] highlighted the presence of several delta fans mainly located on the dichotomy boundary. While a previous delta inventory was compiled by Morgan et al. [3], we aim to update and finalize a complete mapping of delta deposits in order to allow the examination of the evolution and distribution of standing bodies of water on Mars. The objective of our project focuses on the production of a global catalogue of water-related features at the Martian surface, which are commonly studied separately or at smaller scales.</p><p>Globally, we located around 150 deltas among which many were not previously included in published literature [e.g. 1,2,4]. We then examined the deltas based on two main traits. Firstly, we measured the length of the feeding channels since it may be (i) a proxy for the duration of the aqueous activity in the channel-delta system, and (ii) proportional to the age of the delta [2]. The latter relationship links older deltas near Chryse Planitia (>3 Ga) to longer valleys, while younger deltas are usually fed by shorter valleys [2]. Secondly, we measured the elevation of the delta population and compared the obtained dataset with the hypothesized sea level elevation of -2540 &#177; 177 m firstly suggested by Di Achille and Hynek [1] for a northern ocean through the analysis of deltas.</p><p>We observed that, if the relationship between feeding channel length and delta age found for a sub-group of the population [2] is applicable as a rule of thumb to all deltas, many of the deposits have the potential to be Hesperian or Amazonian in age. They would thus be younger than the ocean that might have occupied the northern lowlands during the Noachian-Hesperian boundary period [1] and thus be unrelated to a global sea level range. In fact, less than half of the delta population is related to medium/long feeding channels (>30 km). Abundant pristine morphologies, both related to channels and deltas, also supports the hypothesis that part of the population is younger than Noachian. Additionally, the large variety of elevations where the deltaic deposits can be found and the very small amount of deltas included in the sea level elevation range proposed by Di Achille and Hynek [1] raise questions about the generation and environmental implications of these features, especially when seen at global scale.</p><p>&#160;</p><p>[1] Di Achille, G. & Hynek, B. M., Nat. Geosci. 3, 459&#8211;463 (2010).</p><p>[2] Hauber, E. et al., J. Geophys. Res. E Planets 118, 1529&#8211;1544 (2013).</p><p>[3] Morgan, A. M., et al., Lunar Planet. Sci. Conf. (2018).</p><p>[4] Ori, G.G. et al., J. Geophys. Res. E Planets 105, 17629&#8211;17641 (2000).</p>
Abstract Hollows on Mercury are small (hundreds of meters ‐ few kilometers), shallow (tens of meters), irregular depressions typically found in clusters, often associated with impact craters, and likely formed by the loss of volatile materials. While their exact formation process remains debated, various hypotheses suggest sublimation or space weathering. In this study, we analyzed the global distribution of hollows, exploring their spatial patterns and relationships with key geological features. Our findings challenge the idea that hollows arise from a single volatile‐rich surface layer, suggesting instead that volatiles are dispersed throughout the crust. Hollows show no correlation with specific geological units or elevations, indicating no singular volatile source. Moreover, the transitory nature of hollows is suggested as they are rare in older, degraded craters but common in younger ones or older craters with deep‐seated features, hinting at a link to the reworking of materials through impacts or volcano‐tectonic activity.
Outputs of the 3D geo-modeling of the layered unit inside Crommelin crater (Mars). This model is based on morphostratigaphic mapping explicit modeling approach. The package contains the basemaps and geo-modeled meshes.
Abstract The evolution of the Ladon basin has been marked by intense geological activity and the discharge of huge volumes of water from the Martian highlands to the lowlands in the late Noachian and Hesperian. We explore the potential of the ExoMars Trace Gas Orbiter/Color and Stereo Surface Imaging System color image data set for geological interpretation and show that it is particularly effective for geologic mapping in combination with other data sets such as HiRISE, Context, and Compact Reconnaissance Imaging Spectrometer for Mars. The study area displays dark lobate flows of upper Hesperian to early Amazonian age, which were likely extruded from a regional extensional fault network. Spectral analysis suggests that these flows and the underlying rocks are ultramafic. Two distinct altered levels are observed below the lobate flows. The upper, yellow‐orange level shows hundreds of structurally controlled narrow ridges reminiscent of ridges of listwanite, a suite of silicified, fracture‐controlled silica‐carbonate rocks derived from an ultramafic source and from serpentine. In addition to serpentinite, the detected mineral assemblages may include chlorite, carbonates, and talc. Kaolin minerals are detected in the lower, white level, which could have formed by groundwater alteration of plagioclase in the volcanic pile. Volcanism, tectonics, hydrothermal activity, and kaolinization are interpreted to be coeval, with hydrothermal activity and kaolinization controlled by the interactions between the aquifer and the hot, ultramafic lobate flows. Following our interpretations, East Ladon may host the first listwanite ridges described on Mars, involving a hydrothermal system rooted in a Hesperian aquifer and affecting ultramafic rocks from a magmatic source yet to be identified.
Abstract In the area of Arcadia Planitia in the Northern hemisphere of Mars, mounds indicating fluid and sediment emissions have been already recognized. Here, we show that through fractal and fracture‐spacing analyses of a large vent population it is possible to infer the mechanical layering of the underlying subsurface. Our work includes the mapping of an entire population of 9,028 vents over an area of 122,000 km 2 . The analysis of mound distribution at the surface led to the formulation of inferences about the subsurface feeding conduits, and to the identification of three mechanical discontinuities at c. 4–5, c. 14–23, and c. 50–55 km. This evidence matches the mechanical stratigraphy recorded by the InSight NASA mission, and is in agreement with independent previous subsurface global modeling, supporting our conclusions.
Abstract We report on evidence for fluid circulation in the upper crust of Mars, which could create environments favorable for life and its development. We investigate the nature of the thumbprint terrains covering part of Arcadia Planitia in the Martian northern hemisphere. Our analytic procedure allowed us to (i) hypothesise a potential relationship between these thumbprint terrains and an inferred underground fracture network that extends to where the clathrate-rich cryosphere contacts with the underlying hydrosphere; (ii) support the hypothesis that these thumbprint terrains are made of fine grained loosely packed materials erupted from deep beneath the subsurface mobilized by water; and (iii) date the thumbprint terrains of Arcadia Planitia to ~370 Ma. We conclude that the study area is an area worthy of astrobiological investigation, bringing water and fine grained sediment from depth to the surface for investigation.
