PARAGRAPH text Arial narrow , 9pt, justified, vertical space between line = 9 Provide in this paragraph a summary of the tectonic and sedimentary settings of your study area with appropriate references MINIMUM REQUIREMENT Provide in this paragraph a summary of the global organisation of the deposits, focussing on the Messinian markers - with appropriate references MINIMUM REQUIREMENT

3. GULF OF LIONS Authors: Lofi J., Berné S. & Gorini C.

OPTIONAL: This paragraph can be suppressed, changed, or mixed at your convenience with the "MARGIN ARCHITECTURE & MESSINIAN SALINTY CRISIS"

arial narrow, 8pt

Atlantic ocean

TECTONIC AND SEDIMENTARY SETTINGS width 1pt The Gulf of Lions is a passive continental margin characterized by: - an overall high subsidence and high sedimentation rate during the Miocene that led to the construction of a thick and wide continental shelf [Gorini, 1993]; such a large shelf was easily eroded and shaped during the MSC and furnished a large amount of sediment to the basin [Lofi et al., 2005; see also "MSC Clastics"]. - a Late Miocene tectonic phase that affected the western shelf [Mauffret et al., 2001] and played an important role on the Messinian river patterns, the location of the maximum erosion on the shelf, and the location of the clastic depocentres downslope [Lofi, 2002; Lofi et al., 2005; Gorini et al., 2005]. - a relative tectonic stability of the Languedoc-Roussillon margin since the end of the crisis, as indicated by the unfaulted gently prograding Plio-Quaternary sequence (figs 3.4 & 3.6), that enabled the Messinian markers to be preserved in a configuration close to the initial one.

0

1

depth (km bsf)

PLIO-QUAT clay, micaceous grey claystones marls, shells LOWER PLIOCENE silts, silstones ME MIDDLE-UPPER marlstones, marls, MIOCENE siltstones marlstones MIDDLE MIOCENE dolomite BURDIGALIAN? marlstones, limestones AQUITANIAN? silstones, limestones shells limestones, LOWER conglomerates, AQUITANIAN anhydrite conglomerate sandtones, DEVONIAN? limestones PERMIAN-TRIAS schists & schists.

Figure 3.3. Rascasse exploratory well [Chevron Oil Company de France, 1979] drilled on the inner shelf [modified from Lofi, 2002]. The thick Miocene sequence is eroded at the top (MES) and overlain discordantly by the post-MSC PQ sequence (see borehole location in figure 3.2).

0

Corsica Provençal basin Sardinia

2

N43°

4 5 6

R

Mediterranean sea

Figure 3.1. Relief map of the western Mediterranean showing the location of the Gulf of Lions. This margin forms the northwestern part of the Provençal basin, which results from a short Oligo-Aquitanian rifting event that separated the Corsica-Sardinia microplate from continental Europe [Le Pichon et al., 1971]. At the begining of the Messinian salinity crisis, the Provençal basin was already deep [Steckler and Watts, 1980] and the area consisted of an already thick and large Miocene continental shelf allowing the development of submarine canyon networks during the Middle-Upper Miocene (fig. 3.4; see also Lofi and Berné [2008]).

pre-rift basement

Pyreneans N42°

e

Spain

Rhone deep sea fan

Fig

.3

.4

Figure 3.2. Morpho-bathymetric map of the Gulf of Lions (modified from "Morpho-bathymetry of the Mediterranean Sea", MediMap Group et al. [2005]). The area is characterized by a large shelf gently sloping seaward to a shelf-break. The continental slope is incised by numerous sub-marine canyons. Blue dots: boreholes; R: Rascasse borehole shown in figure 3.3.

150 km MSC DEPOSITION Salt extensional structures tectonics

SE

contractional structures

Deep basin Messinian UU MU LU

CU

TS BS

PQ ?

?

?

Mio

Figure 3.4. Dip line drawing of the western Gulf of Lions margin illustrating the general architecture of the deposits (see location in figure 3.2). The large, thick, faulted Miocene sequence (Mio) has been largely exposed and eroded during the drawdown phase, whereas the deep basin and lower slope received the products of the erosion (complex unit, CU) and accumulated a three-phased depositional sequence (LU, MU & UU). Modified from Lofi and Berné [2008].

LONG TERM IMPACTS OF THE CRISIS The effect of the MSC persisted after the achievment of this event. The Gulf of Lions margin has been flattened during the MSC sea-level drop, giving a mean gradient of 1.5°, which is less than the normal stable slopes of passive margins (about 3°). This created a large space for accommodating post-Messinian sedimentation that has been strongly controled by the morphology of the Messinian canyons onshore [Clauzon, 1973] and Messinian valleys beneath the present-day shelf [Lofi et al., 2003a; Duvail et al., 2005]. At the present time, most of the Mediterranean coastal porous aquifers are observed in the coarse grained Plio-Quaternary deposits [eg. Aunay, 2007] infilling Messinian topographic lows. In the basin, the Plio-Quaternary sedimentation has been partly controled by salt tectonics [eg. Dos Reis et al., 2005]. One can refer to Berné and Gorini [2005] for more details on the history of the Gulf of Lions margin.

SEISMIC DATA - CALMAR (1997, R/V Atalante,B. Loubrieu, Ifremer): CAtalano-Languedocian MARgin [Berné et al., 1999], multi-channel profiles acquired at 10 knots. - MARION (2000, R/V Le Suroit, S. Berné, Ifremer): MARgin of Gulf of LIONs, HR 24 channels. - ACHERE and LRM96 (Languedoc-Roussillon-Maritime 96, 1996) TOTAL Oil Company, multi-channel profiles (no informations on sources and processing). - Numerous seismic data from the 80's involving conventional and industrial seismic reflection profiles exist over the study area. EXPLORATORY WELLS Nine exploration wells have been drilled offshore (blue dots in figure 3.2). Drilling reports are summarized in Guennoc et al. [2000]. Biostratigraphic data are available for some of the wells [Cravatte et al., 1974].

Acknowledgements: this work was undertaken as part of the ECLIPSE I, II & GDR "Marges" research programmes. The authors wish to thank TOTAL and IFREMER for seismic data access.

ACKNOWLEDGEMENTS Arial italic, 7pt, streched by 82% DO NOT CHANGE LOCATION MINIMUM REQUIREMENT

REFERENCES use [ ] for references use et al. (arial italic, 9pt streched by 82%) please provide your reference list on a seperated word document using the proper editing (see provided word document) . All the references wil be compilated in a single list at the end of the atlas book.

Arial narrow bold, 11 pt Figure numbering: 3=number of the study area (will be updated at a later stage) A= sheet "settings" (B= sheet "Surfaces"; C=units)

FIGURE TITLES Arial narrow, 7 pt, vertical space between lines=7 Figure numbering: increment the figures from 1 to X. Keep incrementing when you change sheet

PROVENÇAL BASIN

N41°

First Miocene submarine canyon BES

Eroded Late Miocene anticline (Mauffret et al., 2001)

STUDY AREA COLOR: please choose a color that you are going to use from place to place in your sheets. The frame is getting out of the print area. This is normal, please do not change the width and position of this frame DO NOT CHANGE LOCATION

E7°

op l sl

a

ent

ntin

Co

100

First post-Messinian submarine canyon

E6°

Continental shelf

Miocene

3

E5°

E4°

France

Gibraltar strait

PQ

1

E3°

Alps

MSC EROSION Post-MSC Plio-Quaternary margin progradation MES

E2°

STUDY AREA

50

NW

N44°

FRANCE

SPAIN

MARGIN ARCHITECTURE & MESSINIAN SALINTY CRISIS Dip line drawing across the western margin (fig. 3.4) shows the general organisation of the sediments on the Gulf of Lions. At the bottom the subtratum has been structured in horsts and grabens during an Oligo-Aquitanian rifting phase. It is overlain by a thin syn-rift and a thick post-rift Miocene sequence (Mio; fig. 3.4), eroded at the top by the Margin Erosion Surface (MES; figs 3.3 & 3.4). The MES correlates basinward with the Messinian clastics (CU) and the deep basin trilogy (LU, MU, UU). At the top, the Plio-Quaternary prograding sequence (PQ) reflects the reconstruction of the margin since the achievment of the MSC and the refilling of the Mediterranean sea with Atlantic waters.

2

Any borehole data available in the study area or close to (including DSDP, ODP or industry boreholes)

REGIONAL SETTING

3.A- GULF OF LIONS

PARAGRAPH TITLES Arial narrow bold, 9pt

SHEET TITLE: Arial Bold Itlaic, 14pt, streched by 82% DO NOT CHANGE LOCATION

General bathymetric map of the study area with the seismic coverage, boreholes.... etc MINIMUM REQUIREMENT text: Arial narrow, 8 pt or 10 pt LOCATION MAP IN COLOR line thickness: 0.25; 0.75; 1, 1.5 or 2 use the one provided in the frame 1pt "useful_material" file do not write outside MINIMUM REQUIREMENT arial narrow, 8pt this frame

Fig. 3.10

Authors: Arial, italic, 9pt, streched by 82%. Author ranking is at your convience. It can be different from one sheet to another one DO NOT CHANGE LOCATION

Time (sec TWTT)

AREA NUMBER: use whatever number . This will be updated at a later stage, once the total number of participants will be known. DO NOT CHANGE LOCATION

TITLE: Arial Narrow Bold, 30 pt - color black If you do not have the Arial Narrow Bill you can use Arial and strech it by 82% DO NOT CHANGE LOCATION

NOTE : THE ORGANISATION OF THE FIGURES AND PARAGRAPH CAN BE CHANGED IN THE SHEET AT YOUR CONVENIENCE. HOWEVER, TRY TO KEEP THE ORGANISATION HARMONIOUS AND ALIGN THE MATERIAL ON THE OUTER FRAME

Line drawing (dip oriented) across the study area shwoing the main characteristics of the margin. Use the color code and labelling for the MSC surfaces and depositional units (refer to the "useful_material.ai" file). MINIMUM REQUIREMENT LINE DRAWING text: Arial narrow, 8 pt line thickness: 0.25; 0.75; 1 ; 1.5 or 2 frame 1pt vertical/horizontal scale gradations= 0.5 pts MSC markers color and thickness = refer to "useful_material.ai file"

Presentation of the data used , emphasizing the seismic data MINIMUM REQUIREMENT