Submarine channel-levee systems represent one of the most significant features of sediment transfer on Earth and one of the final segments in source-to-sink routing systems. As such, they serve as conduits as well as intermediate or final storage for large volumes of sediment, paleoenvironmental signals, and pollutants on their way to the deep ocean. Over the years, these systems have been studied through a variety of methods, including: (i) outcropping analogs; (ii) seismic data, occasionally integrated with core analysis; (iii) numerical modeling and physical experiments, and more recently; (iv) repeated multibeam bathymetry and (v) direct measurement of sediment gravity flows. However, as we are able to show in this study, there are still questions about the inherent evolution of these systems that need to be addressed. In this study, we focus on the sedimentary processes and depositional products of submarine channel-levee systems through the characterization, analysis and interpretation at different scales of outcropping analog systems of the Upper Cretaceous Tres Pasos and Cerro Toro Formations in the Magallanes-Austral Basin. In the first research-chapter, Chapter 2, we analyze the transition between laterally offset and vertically stacked channels on a previously undocumented, seismic-scale outcrop of the Tres Pasos Formation. This change in stacking pattern has been widely recognized in submarine channel systems, however, the stratigraphic and sedimentologic details and implications to general conceptual models have not been addressed in the past. Our observations indicate that in between these two depositional architecture styles there is a significant phase of erosion and bypass at a complex-scale (or larger) and that the relief achieved via this deep incision of one or multiple simultaneously active conduits was the necessary condition to promote flow stripping processes and associated overbank deposition. In addition, we discuss the presence of an unusual intra-channel lithofacies association observed directly overlying one of these incisions, which we interpret to represent the along-strike expression of bedforms associated with supercritical flow processes that are found in modern channels and some ancient channel-fill successions. In the next research chapter, Chapter 3, we characterize a 500 m thick fine-grained dominated sedimentary succession interpreted as overbank deposits of the Cerro Toro Formation that have been affected by synsedimentary faulting and crosscut by an extensive injectite network. The scale of this outcrop allows us to resolve the relationship between sedimentary packages and structural features that are commonly overlooked or beyond the resolution of datasets derived from other sources by using high-resolution measurements and quantitative analysis at a cm scale. The orientation of synsedimentary normal faults, paleocurrent directions, and characteristics of 10-36 m thick sandstone-prone intervals suggest a model of overspilling turbidity currents (from the main axial channel belt to the west) on a large levee-slope that might share deformational mechanisms with other depositional slopes. Finally, in Chapter 4, we use detrital zircon U-Pb geochronology to determine maximum depositional ages of seven sandstone samples attributed to the axial channel-belt of the Cerro Toro Formation and shallow-marine deposits of the Dorotea Formation, which extend the chronostratigraphic framework for Ultima Esperanza 55 km southward to help reduce the gap between field sites in the Ultima Esperanza and Magallanes provinces. Based on these new data, we hypothesize that the conglomeratic-rich deposits at this location, which have generally similar lithofacies and large-scale stratigraphic architecture to the Cerro Toro Formation, are unlikely to represent the southward extension of the well-studied axial channel belt deposits to the north, and therefore they potentially represent their own sediment routing system emanating from erosional catchments in the fold-thrust belt to the west. This chapter highlights the value of establishing a chronostratigraphic framework to reconstruct ancient paleogeography in addition to interpretation based purely on observable sedimentary parameters. / Doctor of Philosophy / Turbidity currents are one of the most common processes in in deep-marine environments, they are sediment-laden flows that move downslope due to an excess of density caused by the sediment they carry. They occur under a wide range of geomorphologic configurations, one of such are submarine channel-levees systems. A submarine channel-levee system is a composite geomorphologic feature in the ocean floor consisting of a concave, long-lived sedimentary conduit flanked by parallel depositional highs that is orders of magnitude longer in its downslope longitude than its width. These systems have a worldwide distribution and can be found in every tectonic setting. They represent one of the final segments in sedimentary routing systems and their study is of great importance for numerous reasons, including (i) as hydrocarbon reservoirs, (ii) to mitigate submarine geological hazards that might affect human infrastructure, (iii) their role in the carbon cycle as they transport and bury organic carbon, (iv) their impact to the marine environment as they disperse human-sourced pollutants, and (v) their capacity to preserve geochemical proxies that record past climate and tectonic history. This dissertation is divided in three research chapters focused on different aspects of the processes and depositional products of submarine channel-levee systems through the characterization, analysis and interpretation at different scales of analog ancient systems now exposed in the mountains of Southern Chile. The use of outcropping sedimentary successions is a common practice to characterize and understand modern environments, as they provide an accessible record of their evolution through temporal scales of hundreds of thousands or even millions of years. From a geologic point of view, this study is located in the Chilean part of the Magallanes-Austral Basin, which in the past was an ocean that reached paleowater depths of ~2,000 m during the Late Cretaceous and that was subsequently filled with sediments that form the different geologic units of the area. Here, we focus on two geologic units that represent deep-marine sedimentation in this ancient ocean, known as the Tres Pasos and the Cerro Toro formations. Our study ranges from the detailed stratigraphic characterization of the transition between two different styles of stacking patterns widely recognized in submarine channel systems and its implications, to the influence of sedimentary structures on hundreds of meters of fine-grained sediments deposited in a large levee subjected to failure, and the use of tiny minerals known as zircons to constrain the depositional age and paleogeography associated to coarse-grained deposits historically attributed to a >150 km long axial channel-belt. The results presented here do not only serve to better understand the configuration of ancient deep-marine deposits in this part of the world, but also have implications to improve our understanding of the fundamental sedimentary processes and the depositional products in deep-marine environments worldwide.

La sédimentation marine récente dans les fosses de subduction est caractérisée par l'interstratification de sédiments hémipélagiques et de turbidites localement intercalées avec les coulées de débris, qui peuvent résulter de la destabilisation des pentes continentales par de tremblements de terre. La marge d’Equateur est constituée par une forte érosion tectonique qui contribue à la formation d'une fosse profonde remplie d'une suite complexe de faciès sédimentaires. La sédimentation par écoulements gravitaires est omniprésente le long de la marge et les faciès vont de dépôts de transport de masse d'épaisseur métriques latéralement continus à des turbidites d'épaisseur centimétriques isolées intercalées avec des couches d'hémipélagites, de volcanoclastiques et de téphras. Nous présentons l'interprétation de la bathymétrie, des profils sismiques à haute résolution et des données pétrophysiques des carottes sédimentaires. L'objectif de cette étude est de décrire la complexité morphologique à la frontière équatorienne de la plaque de Nazca où un ensemble d'aspérités marines profondes ont subducté à différentes échelles, et ses conséquences sur la distribution latérale des sédiments dans les différents sous-bassins. La marge équatorienne comprend trois segments géomorphologiques: Le segment nord, situé au nord de la crête Carnegie, est caractérisé par une large (5-10 km) et profonde fosse (3800-4000 m), une pente continentale ravinée et une plate-forme (10-40 km de large) avec subsidence active. Le segment central en face de la crête de Carnégie montre une fosse étroite (0-5 km de large) et peu profonde (3100-3700 m), la pente escarpée et ravinée, sans canyons, et plateau continental étroit de 15 à 40 km de large caractérisé par des zones d'affaissement et de soulèvement actifs. Enfin, le segment sud, situé au sud de la crête Carnegie, présente une large (5-10 km) et profonde fosse (4000-4700 m), une pente continentale pauvre en sédiments avec des systèmes de canyons bien définis et une large plate-forme de subsidence (20-50 km). La dynamique sédimentaire le long de la marge est évaluée par l'analyse de 15 carottes sédimentaires dont la description visuelle, les photographies à haute résolution, l'imagerie par rayons X, les données XRF et les propriétés pétrophysiques conduisent à l'identification de 11 faciès sédimentaires caractérisant 7 processus sédimentaires: dépôts de turbidite, hémipélagites, téphras, dépôts de coulées de débris, homogénites, des slumps et des dépôts de carbonate de ooze. Les âges des dépôts sont définis par la datation au radiocarbone des sédiments hémipélagites. Les âges vont de 500 à 48000 ans BP. Les profils sismiques à haute résolution permettent de définir 3 echo-faciès: transparent, stratifiés et chaotiques. Le facies transparent est principalement associé aux dépôts d'homogénites, le facies stratifié est associé aux dépôts interstratifiés turbiditique-hémipélagique et le facies chaotique est associé à des dépôts gravitaires grossiers. Le remplissage de la fosse représente un enregistrement lacunaire mais important de l'histoire de la marge de subduction. De grandes coulées de débris se déplaçant vers l'est dans les deux séquences inférieures du remplissage de la fosse sont initiées le long de la paroi extérieure de la fosse, le long de grandes failles normales dues à la flexion de la plaque océanique subductante. Les sédiments de la séquence supérieure du remplissage qui nappent la fosse sont plus largement fournis par la paroi interne de la fosse mais avec un fort contrôle de la ride de Carnegie. En conséquence, la profondeur, la fréquence, l'épaisseur, la composition et la disposition latérale des dépôts sédimentaires varient grandement entre le nord et le sud. Les grands méga-lits simples, les slumps, les coulées de débris et les homogénites sont situés dans les segments nord et sud. Ils sont déclenchés par de grands escarpements de failles régionales, dans le Nord / Recent deep marine sedimentation in subduction trenches is characterized by the inter-stratification of hemipelagic and turbidite sediments locally interbedded with debris flow, which can result from continental slope shaking triggered by earthquakes. The active margin of Ecuador comprises tectonic erosion that contributes to the formation of a deep trench filled by a complex suite of sedimentary facies. Gravity flow sedimentation is ubiquitous along the margin and facies range from laterally continuous m-thick mass transport deposits to isolated cm-thick turbidites intercalated with hemipelagite, volcanoclastics and tephra. In this study we show interpretation of swath bathymetry, high-resolution seismic profiles and petrophysical data from cores. The objective is to describe the morphologic complexity on the Ecuadorian border of the Nazca plate where a set of deep marine asperities is subducting at different scales, and their consequences on the distribution of sediments in the different sub-basins. Ecuadorian margin comprises three geomorphological segments: The northern segment, northward of the Carnegie Ridge, is characterized by a wide (5-10 km) and deep trench (3800 – 4000 m), a gentler gullied continental slope and a shelf (10-40 km wide) with active subsidence. The central segment facing the Carnegie Ridge, is strongly influenced by the subduction of the Carnegie ridge which induces a narrow (0–5 km wide) and shallow trench (3100 – 3700 m depth), a steep and gullied slope with no canyons and a 15–40 km wide shelf characterized by areas with active subsidence and uplift. Finally, the southern segment, southward of the Carnegie Ridge, presents a wide (5–10 km) and deep (4000–4700 m) trench, a starved continental slope with well-defined canyon systems and a wide subsiding shelf (20–50 km). The sedimentary dynamics along the margin is evaluated by the analysis of 15 cores. Visual description, high-resolution photographs, X-Ray imagery, XRF data and petrophysical properties led to the identification of 11 sedimentary facies that characterize seven sedimentary processes: turbidites, hemipelagites, tephras, debris flows, homogenites, slumps, and ooze carbonate deposits. Age of the deposits is defined by radiocarbon age dating of hemipelagic sediments. Ages range from 500 to 48,000 years BP. High-resolution seismic profiles allow definition of three echo-facies: transparent, layered and chaotic. Transparent echo-facies is mainly associated to homogenite deposits, layered echo-facies is associated to the turbiditic-hemipelagic interbedded deposits and chaotic echo-facies is associated to reworked gravity flow deposits. The trench fill represents a lacunar but important record of the subduction margin history. Large eastward debris flows in the lower two sequences of the trench fill are provided by the trench outer wall as a results of slope failures along normal faults due to the downward bending of the oceanic plate. The sediment of the upper sequence of the trench fill draping the trench floor, are largely provided by the inner trench wall strongly controlled by the Carnegie Ridge. As a result, depth, frequency, thickness, composition and lateral disposition of the deposits vary greatly from those at north and south. The large, simple mega-beds like slump, debris flows and homogenites are located at the northern and southern segments. They were triggered by large regional faults in the North and enhanced by the activity of sets of splay faults in the South overhanging the seafloor at the slope toe. Small-size, fluid rich events were triggered by subduction of isolated seamounts at the edges of the Carnegie Ridge due to frequent but small destabilizations of an inner trench wall preconditioned by the impacts of successive seamounts. Sets of partly volcanoclastic turbidites in central segment might have been triggered by the complex interaction of slope and continental shelf deformation by seamount subduction