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Title: Supercritical-flow bedforms, facies, geometry and architecture, Middle Eocene, Ainsa and Jaca basins, Spanish Pyrenees
Author: Cornard, Pauline H.
ISNI:       0000 0004 9352 6406
Awarding Body: UCL (University College London)
Current Institution: University College London (University of London)
Date of Award: 2020
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The aim of this PhD is to improve the recognition criteria of supercritical-flow deposits (SFDs) from outcrop and core observations of the Middle Eocene deep-marine sediments of the Ainsa and Jaca basins, to better characterise the architecture of ancient deep-water systems. (1) Based on outcrop observations, six facies associations related to SFDs are defined. These facies associations are binned in two categories. The first group is related to erosional coarse-grained supercritical-flow bedforms, e.g., large- and small-scale cyclic steps. The second group is related to depositional fine-grained supercritical-flow bedforms associated with unstable and stable antidunes and upper-plane beds. (2) Based on 11-months of fieldwork, a hydrodynamic description and interpretation of three contrasting depositional environments in the submarine channel and canyons of the Ainsa Basin is presented, complemented by a hydrodynamic analysis of the correlated submarine lobe-and-related deposits of the Jaca Basin. From this analysis, three parameters are recognised as controlling the distribution of SFDs in a deep-marine system: (i) sandbody confinement, (ii) slope gradient, and (iii) basin geometry. (3) Based on detailed core studies of the Ainsa Basin, three recognition criteria related to SFDs are defined: (i) centimetre-scale scours; (ii) backset lamination, and (iii) planar-parallel lamination. The distribution of SFDs throughout the cores reveals intervals dominated by SFDs separated by intervals with mostly subcritical-flow deposits that can be linked with depositional environments controlled by confinement and slope gradient. This PhD research demonstrates the contribution and value of outcrop and core analyses when linked with observations in modern deep-marine systems, flume-tank experiments and theoretical studies, in understanding flow-processes and deposits, and the evolution of submarine-fan environments. The results of this research should be useful not only for the academic scientific community, but also for the hydrocarbon industry, as it permits the prediction of sedimentological aspects of submarine systems, e.g., the architecture and porosity-permeability relationships.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available