Petroleum Geology: From Mature Basins to New Frontiers – Proceedings of the 7th Petroleum Geology Conference
‘The Proceedings of the 7th Petroleum Geology Conference is the seventh in a series that has become a tradition known as the ‘Barbican’ conferences. They started life over 35 years ago, in 1974, with a focus solely on North-West Europe, and have a reputation, both from the conferences and the accompanying Proceedings volumes, of being at the forefront of petroleum geoscience; the standard reference for successive generations of petroleum geoscientists.
North-West Europe has matured as a petroleum province and, at the same time, the conference series has matured to be a truly global event.
These Proceedings embrace many of the world’s petroleum provinces in a two-volume set. There are sections on Europe, which still provides the heart of the Proceedings; Russia, the former Soviet Union and Circum-Artic; North Africa and the Middle East; Passive Margins; and Unconventional Hydrocarbon Resources.
In addition, the three Geocontroversies debates, highly acclaimed at the conference, are included, as is a summary of the Core Workshop. A DVD complements the books and, in addition to providing electronic versions of all the papers also includes selected posters and video clips from the Virtual Field Trip session; the latter being a major success at the conference. The Proceedings volumes of this seventh conference are therefore a ‘must’ for every petroleum geoscientist’s bookshelf.
Some emerging concepts in salt tectonics in the deepwater Gulf of Mexico: intrusive plumes, canopy-margin thrusts, minibasin triggers and allochthonous fragments
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Published:January 01, 2010
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CiteCitation
M. P. A. Jackson, M. R. Hudec, T. P. Dooley, 2010. "Some emerging concepts in salt tectonics in the deepwater Gulf of Mexico: intrusive plumes, canopy-margin thrusts, minibasin triggers and allochthonous fragments", Petroleum Geology: From Mature Basins to New Frontiers – Proceedings of the 7th Petroleum Geology Conference, B. A. Vining, S. C. Pickering
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Abstract
We summarize four emerging concepts in salt tectonics in the deepwater Gulf of Mexico, selected from a longer list of concepts that have advanced significantly in the last decade. Squeezed salt stocks are common in orogenic forelands, in inverted basins and at the toe of salt-bearing passive margins. Modelling suggests that during early shortening, an inward salt plume from the source layer inflates the diapir and arches its roof. After further shortening, diapiric salt is expelled as an outward plume back into the source layer. Salt canopies are conventionally thought to advance by glacial extrusion. However, almost all modern salt canopies are now buried and can only advance by frontal thrusting. Thrusting allows the salt canopy and its protective roof to advance together, minimizing salt dissolution. Advance is by a roof-edge thrust rooted in the leading tip of salt or by thrust imbricates forming accretionary wedges. Minibasins can sink into salt if the average density of the overburden exceeds that of salt. This requires 2–3 km of burial of siliciclastic fill, yet most minibasins first sink when much thinner. Three alternative mechanisms to negative buoyancy in the deepwater Gulf of Mexico address this paradox of initiation. First, squeezed diapirs inflate, leaving the intervening minibasins as depressions. Second, when a diapir's salt supply wanes, the overlying dynamic salt bulge subsides, allowing a minibasin to form. Third, differential loading causes the thick end of a sedimentary wedge to sink faster into the salt, creating a sag. Spreading salt canopies can transport their dismembered roof fragments tens of kilometres basinward. These exotic fragments are up to 25 km in breadth and comprise anomalously old Mesozoic through Miocene sequences. Strata of the same age underlie the salt canopy or its welded equivalent, signalling lateral transport by thick salt.