Abstract The Cime Dieu de Deify outcrops are located in the Sanguinière Massif, at the western border of the Argentera-Mercantour Massif, 70 km (43 mi) northwest of Nice. They belong to the Grès d’Annot Formation, which outcrops in the Tertiary foreland basin of the French Southern Alps, formed by the Alpine orogeny. From a paleogeographic point of view, the Cime Dieu de Deify outcrops correspond to the central part of the Sanguinière subbasin. This subbasin was one of the tectonically induced narrow troughs (5-10 km [3-6 mi] wide) that controlled the turbidite sedimentation during late Eocene-Early Oligocene times. The Grès d’Annot Formation is 800 m (2620 ft) thick and corresponds to deposits on a sand-rich turbidite ramp. The deposits were probably fed from the Quatre Cantons fan-delta system, 30 km (19 mi) southeastward ( Joseph and Lomas, 2004 ). Thanks to numerous recent gullies, the Cime Dieu de Deify outcrops provide an excellent three-dimensional view of the architecture of the turbidite system. This paper describes the central part of the main cliff, 150 m (490 ft) thick by 1500 m (4920 ft) long; it offers both strike views (Sections 1 to 4) and dip views (Sections 4 to 8) of the architectural elements. The turbidite-ramp deposits are repetitively organized in coarsening-upward, then fining-upward, fourth-order, depositional sequences. Those are approximately 50 m (160 ft) thick, and are characterized by specific facies associations and architectural elements: FA-1 corresponds to muddy-matrix conglomerates (muddy debris flows) that are 20 m (66 ft) thick and can

Abstract During Eocene-Oligocene times, the Grès d'Annot turbidite system (French Alps) was deposited in several tectonically controlled sub-basins, which were mainly fed from a southern major sediment source: the Corsica-Sardinia Massif. In order to establish regional correlations in the southern part of the basin, four kilometre-scale outcrop areas were studied in detail. From south to north these are: the St Antonin, Annot, Grand Coyer and Chalufy areas. The results are: (1) an updated chronostratigraphic framework, (2) a major SE-NW correlation panel, approximately 400m thick and 50 km long, parallel to palaeocurrent directions, within which all stratigraphic units are defined in terms of sedimentology and micropalaeontology and (3) some correlation panels at outcrop scale (around 5 km long and several hundred metres thick), within which all stratigraphic units are defined as before, but with the addition of a direct visual control on correlations, which enables the reconstruction of higher resolution geometry. Seven time-equivalent stratigraphic packages have been correlated from upstream to downstream, making use of micropalaeontologic constraints, and their geometric and facies evolution have been reconstructed through times. This evolution may be related to different stages in the basin deformation, induced by the east to west development of the Alpine foreland basin.

Abstract The Eocene-Oligocene Grès d'Annot series of SE France is a well-known turbidite system for sand-rich gravity deposits. The Grès d'Annot were deposited in several parallel and tectonically controlled elongated sub-basins in the western Alps foreland setting. Regional stratigraphic correlation is used to reconstruct and simulate in three dimensions the large-scale geometry and facies distribution of the Grés d'Annot in the Annot and Trois Evêchés sub-basins. The input parameters of the model are the accommodation, the sediment supply and the transport parameters. These are estimated from the geological model and subsequently adjusted in order to fit the simulation with selected sedimentological sections. From the analysis of the three-dimensional simulated block and of the adjusted input parameter set, an interpretation is proposed in which the relative contribution of external factors controlling the stratigraphic architecture are estimated. The first-order parameters that control the large-scale stratigraphic architecture are the initial basin physiography, the basin-floor deformation and the sediment supply variations through time and space. Small-scale folding and large-scale flexuration of the substratum control the confinement of the system and the available space for sedimentation. Sediment supply and water discharge variations through time are responsible for high frequency (fourth-order) and low frequency (third-order) stratigraphic cycles. This interpretation fits well with a model of a flood-dominated fluvio-turbidite ramp system in which physical continuity exists between the fan delta and the basinal turbidites. In such a tectonically active and confined basin, third-and fourth-order stratigraphic cyclicity might respectively result from uplift-denudation cycles and climatic variations through time. Tectonic activity in the source area may also be responsible for the migration of the main feeding system.

Abstract A 3D stratigraphic database has been constructed from the inspection of 1100 wells and outcrops in the Paris basin. The database contains 88 surfaces correlated at high temporal resolution using sequence stratigraphy. For each well and each surface, the present-day depth, the depositional environment and the lithology between two layers are available. This database provides a key to quantify the tectonics associated with this intracratonic basin and to model the thermal and mechanical processes at the origin of the tectonics. Three types of numerical modelling have been carried out in order (1) to better constrain the long-term thermal subsidence and its cause, (2) to characterize the spatial and temporal evolution of the crustal tectonics during the ‘extensional’ period and (3) to test a lithospheric folding origin during the end-Cretaceous to present-day compressional period. The philosophy of these three models are different. The Chablis model for the lithospheric thermal evolution is used to predict the long-term subsidence of the Paris Basin. The thermal evolution of the lithosphere is computed, taking account of a constant temperature or heat flow at the base of the lithosphere, temperature- and pressure-dependent thermal characteristics, metamorphism in the crust, top-crustal erosion and phase transition in the mantle. The long-term subsidence of the Paris basin results from the decay of a thermal anomaly initiated during late Variscan times. The subsidence data can be explained by short-(Stephano-Autunian) as well as long-(Stephano-Triassic) lasting extension. These hypotheses both implicitly refer to extensional collapse of the Variscan belt. The characterization of the spatial and temporal evolution of the crustal tectonics during the thermal relaxation period has been need to quantify the local effect of the sediment load on vertical crust movements. From sedimentary thickness and bathymetric data, maps of relative tectonics have been drawn at a time scale around 500 ka. These maps show two different tectonic behaviours: (1) narrow regions with a high horizontal gradient of tectonics (faults), and (2) domains with a diffuse subsidence correlated with topographic domes and high rates of sedimentation. The geometrical and temporal characteristics of the regions of diffuse subsidence are compatible with a model of flow of the lower crust if the thickness of the flowing channel is at least 20 km with a viscosity of 10 20 Pas. The Tertiary characteristics of the Paris Basin could be the record of large-scale lithospheric folding. The numerical experiments demonstrate that extremely low (0.2 mm a −1 ) shortening rates are largely sufficient to induce large-scale low-amplitude folding under low maximum values of tectonic stresses ( c. ∼50 MPa). These values suggest that alpine compression is largely sufficient to activate this deformation. From the data collected in this database and from the models described here, the evolution of the Paris Basin is better understood. The Paris Basin Meso-Cenozoic evolution can be described as a long-term thermal subsidence, inherited from the Permian extension and perturbed by intraplate deformations in reaction to the geodynamic events occurring in western Europe, i.e. the Ligurian Tethys opening and closure, and the Atlantic opening. Those tectonic events modify in space and time both subsidence and facies distributions. The Paris Basin was initially an ‘extensional’ basin which progressively evolved into a compressional one, temporarily (lower Berriasian and late Aptian) and then permanently (late Turonian to present day). The present-day geometry of the Paris Basin is the consequence of lithospheric folding occurring mainly during the Tertiary. In consequence, (1) the Paris Basin is not still a subsiding basin but an uplifted area, and (2) during the Jurassic and part of the Cretaceous, the surrounding present-day outcropping basement massifs were subsiding areas flooded by the sea.

Abstract The appraisal of the petroleum potential of a sedimentary basin requires a good evaluation of its source rocks. Sequence stratigraphy appears as a powerful tool for the study of basin-fill histories and is, at present, used for reservoir characterization purposes. Here, we demonstrate that this approach is also a powerful tool for predicting the organic matter distribution by providing a chronostratigraphic framework in which the role of the main parameters controlling its accumulation can be approached. The study was performed at the basin scale and covers a period of 25 m.y. where different orders of superimposed sequences were identified. It investigated the Lias (Lower Jurassic) of the Paris basin, an interval which is known as the bulk source rock for the oil pools in this basin. It used two methods, both applied on wireline logs: (1) the Carbolog method, which estimates the in-situ organic carbon content of the series, showed that the Liassic series was characterized by strong vertical and lateral variations of total organic carbon (TOC), and by the occurrence of several organic-rich intervals besides the well-known Schistes Carton; and (2) the “stacking pattern” method, which produced a consistent framework of three superimposed sequences which are in keeping with the global transgressive-regressive (T-R) Lias cycle. These are the genetic units (0.1 to 0.4 m.y.) of possible climatic origin, the genetic unit sets (0.6 to 1 m.y.) which might be of eustatic origin, and four minor T-R cycles (5 to 8 m.y; i.e., the “stage scale”) of clearly tectonic origin. The study showed a correlation between the distribution of the organic matter and the sequence stratigraphie framework, at the different sequence orders evidenced here, and at the basin scale: (1) the organic-rich intervals are associated with the maximum flooding surface (MFS) and more widely with the end of the rétrogradation (upper part of the transgressive systems tract [TST]) and the beginning of the progradation (lower part of the highstand systems tract [HST]), as long as these occur below the storm-wave base (SWB) ; (2) a hierarchy in the organic content of the organic-rich intervals is observed, from the upper sequence order to the lower sequence order; that is, the T-R cycles, where the organic-richest intervals are located; and (3) the organic content of an organic-rich interval is generally correlated to its thickness—there is no condensation of this interval basinward. The study also showed that some exceptions, however, may exist in these documented features. The analysis of these results emphasized the predominant role of factors involved in preservation of the organic matter as well as the role of the hydrodynamic processes, which partly accounted for its lateral distribution. Its complex vertical distribution has been related to the superimposition of the different orders of the depositional sequences. Tectonics was of predominant importance at the T-R cycle scale, in controlling the physiographic patterns and the sedimentation accumulation rates. Consequently, we consider that the application of these “rules” for the prediction of organic matter distribution is probably more or less restricted to the same tectonic settings as the Paris basin; that is, the intracratonic basins.