--> The Falkland Plateau Basin Linked Shelf to Deepwater Depositional Systems — Controlling Mechanisms, Stratigraphic Packaging and Petroleum Potential

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The Falkland Plateau Basin Linked Shelf to Deepwater Depositional Systems — Controlling Mechanisms, Stratigraphic Packaging and Petroleum Potential

Abstract

The Fitzroy Basin, in the southern part of the Falkland Plateau Basin, displays many characteristics of a typical passive margin with a series of Cretaceous (Berriasian – Cenomanian) prograding successions on the shelf linked to deepwater systems in the basin. 3D seismic allows for detailed evaluation of both the outer shelf and the slope-to-basin domains. Lower resolution 2D extends the evaluations further landward, but does not link with the onshore areas. This data coverage allows analysis of the source-to-sink relationships, although there is still some uncertainty regarding drainage basin controls. The evaluation of the petroleum potential of these systems and identification of exploration targets depends on analysis of stratigraphic packaging and controlling mechanisms to place these systems into a coherent and predictable framework. The depositional units are made up of 4 successions, each in turn made of 2-5 sequences. Shelf and deepwater successions can be observed to jointly change through time. Shelf successions are all strongly progradational and capped by major flooding surfaces resulting in shoreline regression on the order of 10's of km. Two of the four have well developed compound incised valleys. Shelf margin units vary between successions from relatively thin, low angle clinoform packages displaying a strongly regressive pattern to thick, moderate angle clinoform packages displaying a dominantly aggradational pattern. The degree of erosion within the shelf units differs significantly between successions. The deepwater systems between successions vary from thin flat-lying units to ones with strong compensational stacking and evidence of levees to erosionally confined channel belt packages with no visible levees. The Fitzroy lacks sufficient biostratigraphic control to correlate successions to the eustatic curve. There is significant tectonic movement around this basin to appreciably influence these depositional systems. Likewise, climate changes have affected the sediment supply to this basin. Using a regional dataset we identified how distinctions between successions are reflected in both the shelf and deep basin deposits. Interpretations of the forcing mechanisms responsible for the distinct successions has enabled us to understand these characteristics and better predict the hydrocarbon potential of each play type.