Deep-marine levees are areally extensive features that border submarine channel systems. Compared to the adjacent channel, where episodes of erosion and bypass are commonplace, levees are mostly depositional features that experience little erosion, and therefore high preservation potential of individual beds, and presumably provide a nearly continuous depositional record of transport events down deep-marine slopes. Nevertheless, despite their size, volumetric prominence, and interpretive significance, deep-marine levees have received much less research attention compared to the adjacent channels. Accordingly, the spatial and temporal evolution of levee stratigraphy is much less well understood, in part because of the typically recessive nature of levee deposits exposed in outcrop in the ancient sedimentary record, and insufficient seismic resolution seismic in the modern. Also, although modern deep-marine levees have been shown to sequester a large proportion of the world’s total buried organic carbon, few studies have attempted to assess carbon deposition and preservation in ancient deep-marine levee deposits. In the Isaac Formation of the Windermere Supergroup (Neoproterozoic) of east-central British Columbia, Canada, well-exposed levee deposits display a systematic organization on several dimensional scales. Levee packages (decameter-scale) are interpreted to be due to cyclic changes in the granulometric makeup of sediment being supplied to the system, whereas bedsets (centimeter- to meter-scale) are interpreted to represent systematic and recurring pulses or surges during a single flow event. Furthermore, physical and geochemical characterization of levee strata at Castle Creek has shown that the unique depositional processes in levees can result in the concentration and enrichment of sedimentary marine organic matter (OM), which occurs mostly in banded, mud-rich sandstones deposited under oxic conditions. Organic carbon occurs primarily as nano-scale coatings on clay particles and uncommon sand-sized organomineralic aggregates and discrete sand-sized amorphous grains. The distribution of this OM in levee strata is controlled by a combination of primary productivity, sea level, and rates of continental runoff and detrital terrigenous influx, which collectively are principally controlled by climate. Understanding the stacking patterns, geochemistry, and organic content of ancient levee deposits is important for assessing sedimentation patterns, depositional processes, event frequency and magnitude, paleoenvironmental conditions, and the evolution of ancient ocean and climate systems.

At the Castle Creek study area in east-central British Columbia a well-exposed section about 450 m wide and 30 m thick in the (Neoproterozoic) Isaac Formation was analyzed to document vertical and lateral changes in a succession of distinctively heterolithic strata. Strata are interpreted to have been deposited on a deep-marine levee that was sandwiched between its genetically related channel on one side and an erosional escarpment sculpted by an older (underlying) channel on the other. Flows that overspilled the channel (incident flow) eventually encountered the escarpment, which then set up a return flow oriented more or less opposite to the incident (from the channel) flow. This created an area of complex flow that became manifested in the sedimentary record as a highly tabular succession of intricately interstratified sand and mud overlain by an anomalously thick, plane-parallel interlaminated sand-mud unit capped finally by a claystone.

At the Castle Creek study area, levee deposits are well-exposed over an area of ~2.6 km wide and ~90 m thick. This provides an opportunity to describe their lateral and vertical lithological changes, and accordingly details about their reservoir geometry and stratal continuity. Here, levee deposits are divided vertically into packages, each consisting of a sand-rich lower part overlain sharply by a mud-rich upper part. Each lower part displays a consistent thickening then thinning trend laterally away from its genetically related channel. The characteristics of these packages suggest that they were controlled by recurring changes in the structure of channellized flows, which in turn was controlled by grain size and grain sorting. This ultimately was controlled by short-term changes in relative sea level. Moreover, some mud- and sand-rich strata are rich in residual carbon suggesting that mid-fan levees can serve as source rocks for hydrocarbon generation, and also reservoirs.

An expansive panel of well exposed (periglacial) strata of the Upper Kaza Group permitted a detailed study of the stratal architecture of proximal basin floor deposits in the Neoproterozoic Windermere turbidite system. Detailed stratigraphic and petrographic analyses identified six lithofacies: poorly-sorted, clast-rich mudstone (F1), thin-bedded siltstone and mudstone (F2), thick-bedded, massive sandstone (F3), medium-scale, cross-stratified sandstone (F4), mudstone-clast breccia (F5), and medium-bedded turbidites (F6). The spatial distribution of these facies identify five architectural elements: heterolithic feeder channel deposits (FA1), thin-bedded intralobe turbidites (FA2), terminal splay deposits (FA3), distributary channel deposits (FA4), and isolated scours (FA5). FA 1-4 are genetically related and form the basic building blocks of large-scale basin floor depositional lobes. FA 5, which is isolated to the stratigraphic top of the study area, is interpreted to have formed in a base-of-slope setting, and its superposition on FA 1-4 suggests the long-term progradation of the Windermere turbidite system.

An expansive panel of well exposed (periglacial) strata of the Upper Kaza Group permitted a detailed study of the stratal architecture of proximal basin floor deposits in the Neoproterozoic Windermere turbidite system. Detailed stratigraphic and petrographic analyses identified six lithofacies: poorly-sorted, clast-rich mudstone (F1), thin-bedded siltstone and mudstone (F2), thick-bedded, massive sandstone (F3), medium-scale, cross-stratified sandstone (F4), mudstone-clast breccia (F5), and medium-bedded turbidites (F6). The spatial distribution of these facies identify five architectural elements: heterolithic feeder channel deposits (FA1), thin-bedded intralobe turbidites (FA2), terminal splay deposits (FA3), distributary channel deposits (FA4), and isolated scours (FA5). FA 1-4 are genetically related and form the basic building blocks of large-scale basin floor depositional lobes. FA 5, which is isolated to the stratigraphic top of the study area, is interpreted to have formed in a base-of-slope setting, and its superposition on FA 1-4 suggests the long-term progradation of the Windermere turbidite system.

An expansive panel of well exposed (periglacial) strata of the Upper Kaza Group permitted a detailed study of the stratal architecture of proximal basin floor deposits in the Neoproterozoic Windermere turbidite system. Detailed stratigraphic and petrographic analyses identified six lithofacies: poorly-sorted, clast-rich mudstone (F1), thin-bedded siltstone and mudstone (F2), thick-bedded, massive sandstone (F3), medium-scale, cross-stratified sandstone (F4), mudstone-clast breccia (F5), and medium-bedded turbidites (F6). The spatial distribution of these facies identify five architectural elements: heterolithic feeder channel deposits (FA1), thin-bedded intralobe turbidites (FA2), terminal splay deposits (FA3), distributary channel deposits (FA4), and isolated scours (FA5). FA 1-4 are genetically related and form the basic building blocks of large-scale basin floor depositional lobes. FA 5, which is isolated to the stratigraphic top of the study area, is interpreted to have formed in a base-of-slope setting, and its superposition on FA 1-4 suggests the long-term progradation of the Windermere turbidite system.

An expansive panel of well exposed (periglacial) strata of the Upper Kaza Group permitted a detailed study of the stratal architecture of proximal basin floor deposits in the Neoproterozoic Windermere turbidite system. Detailed stratigraphic and petrographic analyses identified six lithofacies: poorly-sorted, clast-rich mudstone (F1), thin-bedded siltstone and mudstone (F2), thick-bedded, massive sandstone (F3), medium-scale, cross-stratified sandstone (F4), mudstone-clast breccia (F5), and medium-bedded turbidites (F6). The spatial distribution of these facies identify five architectural elements: heterolithic feeder channel deposits (FA1), thin-bedded intralobe turbidites (FA2), terminal splay deposits (FA3), distributary channel deposits (FA4), and isolated scours (FA5). FA 1-4 are genetically related and form the basic building blocks of large-scale basin floor depositional lobes. FA 5, which is isolated to the stratigraphic top of the study area, is interpreted to have formed in a base-of-slope setting, and its superposition on FA 1-4 suggests the long-term progradation of the Windermere turbidite system.

Philosophiae Doctor - PhD / Integrated approaches in the study of petroleum exploration are increasingly becoming significant in recent times and have yielded much better result as oil exploration is a combination of different related topics. The production capacity in hydrocarbon exploration has been the major concern for oil and gas industries. In the present work an integrated approach was made with seismic, well logs and biostratigraphy for predicting the depositional environment and to understand the heterogeneity within the reservoirs belonging to Valanginian (Early Cretaceous) age of Gamtoos Basin, Offshore South Africa. Objectively, the integrated work was mainly based on seismic stratigraphy (seismic sequence and seismic facie analysis) for interpretation of the depositional environments with combination of microfossil biostratigraphic inputs. The biostratigraphic study provides evidences of paleo depth from benthic foraminifera and information about bottom condition within the sedimentary basin, changing of depositional depth during gradual basinal fill during the Valanginian time. The petrophysical characterization of the reservoir succession was based on formation evaluation studies using well logs to investigate the hydrocarbon potential of the reservoir across Valanginian depositional sequence. Further, the static modeling from 2D-seismic data interpreted to a geological map to 3D-numerical modeling by stochastic model to quantify the evaluation of uncertainty for accurate characterisation of the reservoir sandstones and to provide better understanding of the spatial distribution of the discrete and continuous Petrophysical properties within the study area.

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.

The first Isaac carbonate (FIC) is a mixed siliciclastic-carbonate base-of-slope succession in the Neoproterozoic Windermere Supergroup (WSG). Outstanding outcrop exposure at three study areas provided an excellent opportunity to observe the stratigraphic and isotopic evolution of an ancient deepwater mixed turbidite system. Based on lithological and stratal dimensions, the FIC can be subdivided into lower and upper parts suggesting temporal changes in patterns of sediment transport and deposition. δ13Ccarb also changes from -5.2‰ at the base of the FIC to 2.5‰ in the middle and then decreases to -6.3‰ at the top. Notably, the δ13Ccarb of primary cement in FIC strata is substantially more positive than most other Neoproterozoic deep-marine sections, suggesting the retention of their original shallow-marine isotopic signature. Nevertheless, this trend potentially correlates with the EN2 excursion in China and therefore the Gaskiers glaciation (~580 Ma), although better age control of WSG is needed to corroborate this correlation.