Understanding how the fill of bathymetrically complex turbitlite basins evolves, particularly g'auging the extent to which different length scales of bathymetric control are expressed within turbidite basin fills, is a key challenge. The interaction of turbidite systems with their substrate is examined using two complementary datasets; one from outcrops of the Tertiary Annot and Champsaur Turbidite Systems, and one from the modem turbidite systems of the SimI Accretionary Prism, with a view to understanding the extent to which the architectural expression ofthe basin fill represents the composite influence oflocal- and regional-scale slope interactions. Within the Eocene to Oligocene deposits of the Alpine Foreland Basin are a series of turbidite basins, whose development were influenced by early uplift of the Alpine foreland, and which contain spatially complex turbidite basin fills. Presented here is an outcrop case study from the Eastern and Western Champsaur Basins, found today in the Ecrins region of SE France, and separated by the Selle Fault Zone. These basins record the deposition ofdeep-water sediments onto the fringes of the ancestral Pelvoux Massif, itself deformed by local early Alpine-related fold and thrust structures. Within the Eastern Champsaur Basin, sediment facies and architecture are observed to vary systematically around an intra-basinal high, (the bathymetric expression of an early Alpine structure), which is interpreted to have partially contained the turbidity currents, allowing a relatively finer fraction of the flow to be stripped downstream, to the NW. Although the distal preserved remnants of the Eastern Champsaur Basin are truncated by the Selle Fault Zone, the sedimentology of the truncated basin fill suggests that turbidity currents were flowing over and beyond this structure. Within the easternmost part of the Western Champsaur Basin is a NE-feeding submarine channel, structurally truncated in its distal-most preserved section by the Selle Fault. Its form and internal architecture suggest it probably connected to deeper bathymetric levels towards the NE when active, and was therefore likely to have been of greater axial extent than its preserved dimensions. The Selle Fault is interpreted to have separated the volcaniclastic Western Champsaur Basin and the siliciclastic Eastern Champsaur Basin. Thus both the Western and Eastern Champsaur Basins are inferred to have originally been connected to deeper bathymetric levels towards the N or NW, suggesting that the ancestral Pelvoux Massif did not form a significant bathymetric barrier. The SimI Accretionary Prism and adjacent areas are fed by rivers that drain from volcanic Andean terranes which source large volumes of sediment to the Colombian Shelf into the Colombian Basin. Several basin filling styles are recognised, with ~avity current-dominated basins characterised by channel- and sheet-form architecture and hemipelagic dominated fills. Mass wasting-dominated basin fills show evidence both of localised fold-induced degradation, and also are affected by more regional-scale shelf collapse. This collapse is also responsible for the creation of local depocentres into which sediment subsequently accumulates. Both local and regional length scales of bathymetric control are evident within the intraslope basins of the SimI Accretionary Prism, which suggest that both local- and regional scale influences can occur in isolation, or co-exist, within a single part ofa submarine slope system. This study has direct application in aiding the understanding of sand emplacement processes at the fringes of turbidite basins, in particular in defining the genesis of stratigraphic trap geometries, and understanding the length scales of bathymetric control on the composite architecture ofturbidite system basin fills.

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No description available.

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The early growth of normal faults is typically associated with the development of at-surface monoclinal folds and the deposition of wedge shaped syn-rift deposits that typically thin and onlap towards these growth structures. This is especially true in salt-influenced rift basins, where the presence of mechanically-weak, evaporite rich units within the pre-rift succession may serve to decouple folded supra-salt strata from faulted sub-salt strata, resulting in the formation of extensional forced folds in the overburden. However, uncertainties still exist with respect to; (i) the controls of the structural style and kinematics of normal fault growth in salt-influenced rifts; (ii) the syn-rift stratigraphic response to faulting and folding; and (iii) the along-strike variability of these linked structural and stratigraphic relationships in both salt-influenced and non-salt influenced extensional settings. To address these outstanding research issues, an integrated dataset of three-dimensional seismic reflection and borehole data from the Stavanger Fault System (SFS), Egersund Basin, North Sea and field data from the Hadahid Fault System (HFS), Suez Rift, Egypt is used. The results demonstrate that; (i) the structural style of fault growth in salt-influenced basins is primary controlled by the pre-rift salt distribution and thickness, and that the sub- and supra-salt fault populations initiate and grow as brittle elements of a single, geometrically and kinematically coherent structure; (ii) the stratal architecture of and facies variations in early syn-rift deposits are controlled by the growth of normal faults and extensional forced folding, and changes in base-level; and (iii) the along-strike variability in the stratal architecture of and facies variations in early syn-rift deposits are influenced by growth folding and faulting, which may vary markedly in time and space at both the fault-segment and fault-system scales.

This thesis is concerned with the development of fold structures in uniform, well laminated or foliated geological systems. Such structures include monoclinic and conjugate kink bands, 'box' folds and chevron folds. These types of structure occur over a wide range of geological scales in materials or layered systems with a well developed planar anisotropy. The thesis is divided into two distinct sections. The first section (Chapters 1, 2 and 3) is concerned with mechanical models of fold development in uniform multilayers. Chapter 1 contains a review of previous work in this field and particular emphasis is placed on the work of M. Biot. The role of mechanical anisotropy in producing active amplification of folds in uniform, finely laminated multilayers is discussed.

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No description available.

The Malvinas and Austral basins of SE Argentina formed in response to extension and volcanism which commenced from ~168 ± 3 Ma. Termination of syn-rift subsidence in these basins is correlated with oceanic crust formation in the Weddell Sea at 150 Ma. Thermal subsidence preceded up to 1.5 km of water-loaded flexural subsidence in this area during the Cenozoic. The San Jorge basin (central Argentina) formed between ~200-160 Ma. This basin was subjected to a second major extensional phase at ~140 Ma which also resulted in the formation of the Colorado, Salado, and Punta del Este basins to the north. A final period of renewed syn-rift subsidence in these basins occurred at ~100 Ma. Initial extension on the southern African margins began at ~155 Ma with the formation of the Outeniqua basin. Subsidence modelling implies a second extensional event affected the central Outeniqua basin at 135-125 Ma. On the west coast, the Orange basin formed in response to a single rift episode at ~140-110 Ma. Several periods of uplift and denudation dramatically punctuated the post-rift development of each of the southern African offshore basins. Major uplift and denudation events are identified at ~125 Ma, 94 Ma, 84 Ma and 65 Ma. Data from the first wells to be drilled in the North Falkland basin are used to determine the tectonic and thermal evolution of this region. The northern sector of the basin formed as a result of a single rift event at ~168-120 Ma with a maximum stretching factor of <i>b </i>= 1.5. An early post-rift heat pulse in this northern sector may be related to synchronous uplift in the south of the basin. Rifting related to the break-up of Gondwana is correlated throughout the southern South Atlantic marginal basins. The timing, number, and intensity of subsidence events in these basins differed locally, and there is evidence for south-north rift propagation. The post-rift tectonic and thermal histories of these basins show marked regional differences.