The Upper Cretaceous Cerro Toro Formation, southern Chile, is characterised by thinbedded turbidites that envelope a series of coarse-grained, confined slope complex systems, interpreted as part of the Lago Sofia Member. This deep-water slope system overlies basin floor sheets of the Punta Barrosa Formation, and is overlain by the sand-filled slope channels of the Tres Pasos Formation. Particularly distinctive beds, known as TEDs (transitional event deposits), are up to 40 m thick, laterally extensive, have prominent fluted bases, and have a vertical fabric starting with (1) a thin, inversely-graded, clast-supported base; then (2) a normally-graded and clastsupported interval; (3) an increasingly sand and clay matrix-supported conglomerate, with (4) a progressive upwards increase in matrix and normally grading, both in the floating gravel clast and matrix grain sizes, towards the top; and (5) a co-genetic sandstone on top. In the Cerro Toro formation, these TEDs tend to occur as multiple beds in the initial phases of deposition of each channel complex system. The TEDs are highly aggradational, slightly more amalgamated in the channel-axis, and more layered towards the margins. The fabric of these spectacular event beds is described in some detail from measured sections, combined with petrographic analysis and high-resolution field mapping. The 4 km x 200 m channel systems are contained within topographically irregular bathymetric lows that formed sediment pathways, interpreted to be either the result of slope deformation, or contained by poorly preserved, tectonically disrupted or slumped external levee. Syn-sedimentary tectonism is interpreted to be responsible for sharp changes in the system's architecture from channels to ponds, marked by a sharp change in lithofacies from dominantly conglomerates to dominantly sandstones. A refined architectural analysis is proposed, focusing on the recurrent pattern of at least 5 cycles of conglomerate-filled channel systems – ponded sheet sandstones.

Mémoire (M. Sc. A)- Université du Québec à Chicoutimi, 1983. / "Mémoire présenté en vue de l'obtention de la maîtrise en sciences de la terre" CaQCU Document électronique également accessible en format PDF. CaQCU

Mémoire (M.Sc.A.)- Université du Québec à Chicoutimi, 1983. / "Mémoire présenté en vue de l'obtention de la maîtrise en sciences appliquées en géologie" 6 cartes en pochettes. CaQCU CaQCU Document électronique également accessible en format PDF. CaQCU

Thèse (M.Sc.T.) -- Université du Québec à Chicoutimi, 2006. / Bibliogr.: f. 204-211. Document électronique également accessible en format PDF. CaQCU

A quantitative forward model has been developed to investigate the controls on the deposition, erosion, and preservation of passive rift margin stratigraphy. The model includes thermal subsidence, variable absolute sealevel, flexural isostasy, subaerial and submarine deposition on fluvial and marine equilibrium profiles, and the facility to vary sediment supply through time. Results from the quantitative model can be used to reproduce elements of the sequence stratigraphic depositional model. Conducting sensitivity tests demonstrates that variables such as sediment supply and fluvial profile behaviour are likely to be of equal importance to thermal subsidence and eustasy in passive margin stratigraphy. Sensitivity tests with the quantitative model also demonstrate the problems associated with attempting to use a discretised stratigraphic model to investigate unforced cyclicty resulting from complex interactions in stratigraphic systems. Although the model appears capable of producing such unforced cyclical behaviour, this cyclicity is shown to be due to a numerical instability within the model which occurs with certain initial conditions and assumptions. The applicability of the model to observed stratigraphy is tested by comparing specific model output to patterns of stratigraphy from the North American Atlantic margin. The results from this test demonstrate that although the model is in many respects simplistic when compared to the complexities of natural systems, it is nevertheless capable of reproducing some of the basic elements of the observed stratigraphic patterns.

Thèse (M.sc.A.)- Université du Québec à Chicoutimi, 1981. / "Mémoire présenté en vue de l'obtention du grade de maître en sciences appliquées" CaQCU Document électronique également accessible en format PDF. CaQCU

Mémoire (M. Sc. A.)- Université du Québec à Chicoutimi, 1981. / Quatre cartes géologiques sur feuillets pliés, en pochette. "Mémoire présenté en vue de l'obtention de la maîtrise es sciences appliquées" CaQCU CaQCU Document électronique également accessible en format PDF. CaQCU

This Dissertation combines the investigation of the sedimentological impacts of the Deepwater Horizon (DwH) blowout event in the deep-sea benthos, with the refinement and advancement of methods and approaches for high-resolution investigations of events preserved in sedimentary records. An approach that combined, rapid collection of cores, a continued annual time series collection of cores, and high-resolution sampling and analyses, in particular short-lived Radioisotopes (SLRad), enabled the temporal resolution required to detect the sedimentary response to the short-duration DwH event, and evaluate post-event sedimentation patterns at a comparable time scale (months). The collection of 179 sediment cores from 80 sites between the fall of 2010 and 2016 included four sites that were utilized as an annual time-series collection to define the sedimentary response to the DwH blowout event and how the sedimentary system evolved/recovered post-event. High-resolution (2mm) sub-sampling was utilized to maximize the temporal resolution of analyses and age control using SLRad. The rapid collection of cores to define the immediate benthic impact(s), as well as the use of time-sensitive indicators of the event that may degrade over time, as well as indicators for very short time scale (months) sedimentation, such as 234Thxs. 234Thxs inventories and mass accumulation rates (MAR’s) were one of the most diagnostic characteristics of the sedimentary response. The DwH blowout event led to a Marine Oil Snow Sedimentation and Flocculent Accumulation (MOSSFA) event that caused a depositional pulse to the seafloor. This was defined by increased sedimentation rates and the shutdown of bioturbation as indicated by 234Thxs inventories and MAR’s. The annual collection of sediment cores as a time-series allowed for continued high-resolution analyses and use of 234Thxs to determine post-event sedimentation rates and baselines on monthly time scales for direct comparison to the depositional pulse. Within ~one year sedimentation rates decreased and within three years site specific return of bioturbation occurred and sedimentation rates on monthly scale (234Thxs) stabilized. Also, within ~three years the sedimentary signature of the depositional pulse became undetectable with respect to sediment texture and composition possibly due to dilution of this indicator by mixing/bioturbation and/or compaction of the event layer. Without the use of high-resolution sampling and geochronological tools such as 234Thxs the depositional pulse would not have been detected in the sedimentary system. The continued use of these high-resolution methods allowed for further defining the magnitude of the sedimentary response to the DwH event as well as provide baseline sedimentation patterns at a monthly time scale. The annual time series defines the post-event evolution of the sedimentary system as well as the assessment of the post-depositional alterations that influence the integration and preservation of such sedimentation events in the sedimentary record. This includes the potential for re-mobilization of event sediments, potential re-exposure of ecosystems to contaminated sediments and redistribution of event sediments. Alternatively, burial and alteration of the sedimentary signature over time influences the preservation potential of sedimentation events such as DwH, with decreasing ability to detect events due to bioturbation, degradation of signature and compaction. The refinement of methodology and approaches, in particular short-lived radioisotope (SLRad) geochronology, allowed for the high-resolution determination of the sedimentary impacts of the DwH blowout event. In turn, the opportunity to investigate the DwH event in real time provided the opportunity to advance high-resolution methodologies in an applied fashion. Continued refinement of high-resolution approaches and methods, in particular geochronologies, will allow for the detection of short-duration and subtle sedimentary events in real time as well as in the sedimentary record. Through the application of such approaches and methods to real events, these methods can be further refined and assessed for their utility and limitations.

Abstract not available