A study of the architecture of deep-marine sheet systems in a rift basin fill: The Kongsfjord Formation, Finnmark, North Norway
Depositional models of sand-prone deep-water sheet systems are limited in the literature to those that have been developed within the archetypal fan-classification. The majority of models of sheet-systems relate either to submarine fan sand-rich lobes or basin-wide systems that occur at abyssal dept...
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| Format: | Doctoral or Postdoctoral Thesis |
| Language: | English |
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UCL (University College London)
1997
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| Online Access: | https://discovery.ucl.ac.uk/id/eprint/10101701/1/out.pdf https://discovery.ucl.ac.uk/id/eprint/10101701/ |
| Summary: | Depositional models of sand-prone deep-water sheet systems are limited in the literature to those that have been developed within the archetypal fan-classification. The majority of models of sheet-systems relate either to submarine fan sand-rich lobes or basin-wide systems that occur at abyssal depths over thousands of metres deep. Through the use of extensive laterally correlated sedimentary logs, this thesis presents a new channel-lobe transition interpretation for the Nålneset section of the Kongsfjord Formation, Finnmark, northern Norway, previously described as forming the inner-fan depositional environment of a major submarine fan. An alternative model is presented for sheet systems in non-fan environments, or in fan environments at a scale an order or more below that of the overall fan gross morphology. This model may provide a suitable analogue for relatively small upper- and mid-continental intraslope basins offshore in the Gulf of Mexico. Basin-slope sand-prone sheet systems of the type described may represent the relatively proximal parts of large submarine fans or isolated and discrete ponded basin fills. The research for this thesis suggests that such sheet systems may be characterised by basin-wide packets of sand, tens of metres thick which are separated by fine-grained intervals. Rapid deposition, indicated by extensive evidence of fluidisation, is the key process in this system; scouring of sediment is of a local nature only. Examples of sheet systems from other depositional environments of the Kongsfjord Formation are discussed, and a quantitative approach is adopted to help characterise the lateral continuity of architectural elements at a variety of scales and from a variety of environments. The overall gross morphology of the Kongsfjord Formation submarine fan, it's correlation with neighbouring deep-marine systems and it's relationship to synchronous development of a mantle plume related to the opening of the Iapetus Ocean are discussed. |
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