Hydrothermal Alteration of Ultramafic Rocks in Ladon Basin, Mars—Insights From CaSSIS, HiRISE, CRISM, and CTX

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

Mappatura planetaria a scala differente: uno sguardo su corpi terrestri privi di atmosfera

L’obiettivo di questa tesi, sviluppata all’interno del progetto Europeo Horizon 2020 PLANMAP, è la produzione di carte geologiche sia standard che innovative su differente scala focalizzate su due corpi terrestri privi di atmosfera di primario interesse per la futura esplorazione Europea, ovvero Mercurio e la Luna. Questi prodotti cartografici, destinati a supportare la futura esplorazione planetaria, mirano non solo a caratterizzare la morfologia superficiale ma anche ad integrare informazioni spettrali e composizionali non individuabili solamente su base morfologica. Per Mercurio, un progetto in corso per la produzione di una serie di carte geologiche regionali a scala 1:3,000,000 per i suoi 15 quadrangoli è iniziato con la produzione di carte geologiche individuali per evolvere successivamente in un piano coordinato di mappatura globale. Con lo scopo di produrre la prima carta regionale a larga scala del quadrante H-9 Eminescu (22.5° N-22.5° S, 72° E-144° E), ho realizzato i) una carta geologica a scala 1:3M, derivata dall’interpretazione morfologica della superficie, e ii) una carta spettrale basata su basemaps a colori, derivata da variazioni di colore all’interno delle unità geologiche identificate, per la porzione orientale del quadrangolo Eminescu. Tali mappe, le quali hanno permesso di concentrare gli sforzi nella iii) definizione di targets di interesse scientifico per lo strumento SIMBIO-SYS a bordo della missione BepiColombo di ESA-JAXA. Dal confronto dei risultati ottenuti si distingue una buona correlazione fra morfologia e variazioni di colore della superficie. La mappatura basata sul colore permette di desumere molte più informazioni riguardo alla superficie di Mercurio rispetto che dall’uso di sole immagini monocromatiche, discriminando fra differenti materiali. Sono stati considerati tra i principali target per la missione BepiColombo peculiari variazioni di colore associate all’esumazione di materiali sottostanti, che presentano verosimilmente una distinta composizione, così come vents vulcanici che non presentano particolari variazioni di colore e crateri fagliati che permettono di derivare la cinematica delle strutture tettoniche. Per quanto riguarda la Luna, invece, diversi tipi di prodotti cartografici sono stati realizzati sulla base di differenti dati, da immagini monocromatiche e a colori a diverse risoluzioni spaziali fino a informazioni multispettrali e all'integrazione di determinazioni di età relative e assolute. L'obiettivo finale di queste carte è quello di fornire uno studio geologico su piccola scala del cratere Tsiolkovskiy (20.4° S, 129.1° E) situato sul lato nascosto della Luna in modo da gettare le basi per una futura caratterizzazione dell’area come sito di atterraggio. Ho pertanto realizzato i) una carta morfo-stratigrafica, derivata dall'interpretazione foto-geologica, ii) una carta spettrale basata su variazioni di colore, derivata dall'associazione di variazioni compositive con le unità morfologiche identificate, iii) determinazioni di età, per discriminare possibili differenze di età basate su variazioni di colore, iv) una carta spettro-stratigrafica, derivata dall'integrazione di informazioni multispettrali, e v) una carta geologica ad alta risoluzione, per la definizione di una possibile area target. I risultati mostrano una chiara correlazione tra morfologie, variazioni di colore e informazioni spettrali e permettono di dedurre più informazioni riguardo alla composizione di ogni unità. Le determinazioni dell'età, in aggiunta, hanno permesso di ricostruire l'evoluzione vulcanica del fondo del cratere di Tsiolkovskiy e di associare variazioni compositive ai suoi eventi di riempimento. La mappatura geologica ad alta risoluzione, infine, mira a richiamare l'attenzione sul picco centrale del cratere e sui massi crollati che lo circondano, che potrebbero rappresentare un interessante target per studiare la composizione della crosta lunare e del mantello.The objective of this thesis, developed within the European Horizon 2020 PLANMAP project, is the production of both standard and innovative geologic maps at different scales focused on two atmosphere-less terrestrial bodies of primary interest for future European exploration, namely Mercury and the Moon. These cartographic products, intended for supporting future planetary exploration, aim not only at representing the surface morphology but also at integrating into the map product spectral and compositional information. For Mercury, an ongoing project for the production of a series of 1:3,000,000 regional geologic maps for its 15 quadrangles started with the production of individual geologic maps to later evolve into a coordinated global mapping plan. Aiming at producing the first large-scale regional map of the H-9 Eminescu quadrangle (22.5° N-22.5° S, 72° E-144° E), I have been realizing i) a 1:3M geologic map, derived from morphologic interpretation of the surface, and ii) a color-based spectral map, derived from color variations within the identified geologic units, for the eastern portion of the Eminescu quadrangle. These maps permitted to better focus on iii) the definition of scientific targets of interest for the SIMBIO-SYS instrument onboard the ESA-JAXA BepiColombo mission. By comparing the obtained results it stands out a good correlation between morphology and surface color variations. The color-based mapping allows inferring much more information about the hermean surface than from monochrome imagery alone, discriminating between different materials. Peculiar color variations associated with the exhumation of underlying materials, possibly presenting a distinct composition, have been considered among the main targets for the BepiColombo mission together with volcanic vents presenting no particular color variations and faulted craters allowing to derive the kinematics of tectonic structures. As concerns the Moon, instead, several types of cartographic products have been realized based on different data, from monochrome and color imagery at different spatial resolutions up to multispectral information and the integration of relative and absolute age determinations. The final aim of these maps is to provide a small-scale geological study of the lunar far side mare-flooded Tsiolkovskiy crater (20.4° S, 129.1° E) in order to lay the groundwork for a future landing site characterization. I have thus been realizing i) a morpho-stratigraphic map, derived from photogeological interpretation, ii) a color-based spectral map, derived by associating compositional variations with the identified morphological units, iii) age determinations, for discriminating possible age differences based on color variations, iv) a spectro-stratigraphic map, derived by integrating multispectral information, and v) a high-resolution geologic map, for the definition of a possible target area. The results show a clear correlation between morphologies, color variations and spectral information and allow to infer more information about the composition of each unit. Age determinations, then, allowed to reconstruct the volcanic evolution of Tsiolkovskiy’s crater floor associating compositional variations to its infilling events. The high-resolution geologic mapping, finally, aims at drawing attention to the central peak of the crater and to the collapsed boulders surrounding it, which could represent an interesting target to study, among others, the composition of the lunar crust and mantle

Color Variegation and Inner Stratified Structure of comet 67P/Churyumov-Gerasimenko

The international space mission Rosetta was approved in 1993 by the European Space Agency (ESA), within the program Horizon 2000 for the exploration of the minor bodies of the Solar System, and launched on 2 March 2004. The spacecraft was constituted by the Rosetta orbiter and the Philae lander, the latter projected to anchor at the cometary nucleus of the comet, collect images and perform superficial analyses. The mission concluded on September 2016 with the controlled landing of the probe on the comet. The instruments onboard the spacecraft were chosen to perform a wide range of analyses, among which image analysis, spectroscopy and spectrophotometry. In particular, the images used in this work were acquired with the imaging system OSIRIS (Optical, Spectroscopic and Infrared Remote Imaging System) and precisely with the Narrow Angle Camera (NAC), projected to acquire high resolution images of the surface in the NUV-VIS-NIR wavelength (Keller et al., 2007). The importance of the Rosetta mission lies in the fact that it is the first mission that set as main objective the close-range study of the nucleus of a comet, approaching specifically the comet 67P/Churyumov-Gerasimenko of the Jupiter-family comets. The spacecraft performed a series of controlled orbits around the comet, allowing its observation, and escorted it during its perihelion passage and, above all, was the first mission to land a lander on the surface of a cometary body. The images acquired by OSIRIS allowed to describe a cometary body with a bi-lobed shape and with vast depressions, pits, scarps, terraces, cuestas, mesas, fractures, mass-wasting deposits, landslides, continuous stratifications and fine material deposits (Sierks et al., 2015; Thomas et al., 2015). Studies on the stratification allowed to detect on both lobes of the cometary nucleus a onion-like stratification, which should have formed previously the merging of the two lobes through a low velocity collision (Massironi et al., 2015; Davidsson et al., 2016). With the aim to identify distinct envelopes of the onion-like stratification and to verify their spectrophotometric variations, two sequences of multispectral OSIRIS NAC images acquired after the perihelion passage and framing the minor lobe of comet 67P where selected. These images were overlapped to build two multispectral cubes to which were then applied photometric corrections to delete the effects due to the different illumination conditions. To the cubes was successively applied a two-classes Maximum Likelihood supervised classification, on which the training areas were selected on the identified consolidated outcrops and relative deposits on the basis of the superficial reflectance and structural elevation defined by the ellipsoid-based model of the internal structure of the nucleus (Penasa et al., acce pted). The classification highlighted the presence of an inner and an outer envelope (each constituted by numerous stata) with different spectral properties, in particular with the inner shell brighter than the other one. These difference could be due to different textural properties or to compositional variations between the two envelopes

Tsiolkovskiy crater, the Moon - Mapping products

Mapping project and additional materials for Tsiolkovskiy crate

GeoPlanet IO10, field data collection - 3D models

Series of photogrammetric models produced during the School on Planetary Geological Mapping and Field Analogues, 202