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3 Days Field Trip, IAS Congress, Toulouse
October 10 – 12, 2017
Seismic-scale fluid migration features in a passive margin setting,
Outcrop analogues from the Mesozoic SE France Basin
, Patrice Imbert
, Sutieng Ho
1) Universit y of Fri bourg, Departem ent of Geo sciences, Chemin du Musée 6, CH -1700 Fribourg, Sw itzerland; 2) Total CSTJF, Avenue Larr ibau, 6400 Pau, Franc e;
3) Nation al Taiwan Univers ity, Depart ement of Geosc iences, N o.1, Sec. 4, Avenue Roosevelt, 10 671 Taipei, Taiwan
Contact: Jean-Philippe.Blouet@unifr.ch; JeanPhilippe.Blouet@gmail.com; Patrice.Imbert@total.com;
This field trip will take place in the SE France Basin, which is filled by an up to 10 km-thick pile of
Mesozoic sediments. These sediments accumulated in a deep embayment that opened onto the
divergent, then drifting northern margin of the Tethys Ocean. Several organic-rich intervals that were
deposited during Mesozoic, had locally reached the mature stage and became biogenic or
thermogenic source rocks. It is evidenced by hydrocarbon seepages in the outcrops and in boreholes.
Although fluid migration study is usually based on petrographic and geochemistry methods, we will
introduce in this field trip the concept of ‘outcrop scale fluid migration features’, namely: sand
injectites and seep carbonates and to some extent mass-transport deposits. We will discuss for each
of these the related fluid pressure regimes, their links to petroleum systems, and inferred seismic
analogues of such bodies based on examples from various sedimentary basins.
The earliest studied outcrop exposes one of the famous ‘Pseudobioherms’ of the Oxfordian Terres
Noires Formation. This spectacular seep carbonate mound (20 m thick) differs in several ways from
the ‘classic’ outcrop of Beauvoisin (and other seep carbonates worldwide); the origin of such
particularities will be discussed based on facies and petrographic analysis, and linked to hydrocarbon
Other outcrops are all found in the Aptian-Albian Marnes Bleues Formation. On the edge of the
basin, a bluff nicely expose seep carbonates on ca. 200 m long, 150 m height, which allows the
description of mappable clustering pattern. The stacked clusters point down to underlying turbidite
channels as possible hydrocarbon reservoir leaking up to the sea floor.
Sand injectites have connected with thick sandbodies and cross-cutting the encasing marly Marnes
Bleues Fm. have been described near Sisteron; their association with dispersed columnar and tubular
carbonate concretions will be examined based on geometric relationships from a couple of hundred
meters to a few kilometers scales.
Finally, a 80-m-thick mass-transport deposit (MTD) will be examined. MTDs are known from
geotechnical modeling to detach on intervals of high fluid pressure, making them “fluid indicators” in
a wide sense. In addition, the outcrop will raise the issue of the significance of kinematic indicators
and highlight some aspects of the mechanical behavior of sediments shortly after deposition.
The outcrop presented here will be visited during a 3 days field trip before the IAS Congress, in
October 2017 in Toulouse. During the journey we will cross the basin; starting from the NW margin
(Vercors) and ending at the foot of the SE margin (Provence). The highlights will include a museum of
regional fossils showing world-class specimens.
For more information please visit