Sedimentary markers in the Provençal Basin (western Mediterranean): a window into deep geodynamic processes

Abstract

International audienceDeep Earth dynamics impact so strongly on surface geological processes that we can use sediment palaeo-markers as a window into the deeper Earth. Derived from climatic and tectonic erosive actions on the continents, and related to eustasy, subsidence and isostasy, the sediment in a deep basin is the main recorder of these processes. Nevertheless, defining and quantifying the relative roles of parameters that interact to give the final sedimentary architecture is not a simple task. Using a 3D-grid of seismic and wide-angle data, boreholes and numerical stratigraphic modelling, we propose here a quantification of post-rift vertical movements in the Provençal Basin (West Mediterranean) involving three domains of subsidence: seaward tilting on the platform and the slope and purely vertical subsidence in the deep basin. These domains fit the deeper crustal domains highlighted by previous geophysical data. Post-break-up sedimentary markers may therefore be used to identify the initial hinge lines of the rifting phase and the subsidence laws

Deep structure of the Santos Basin‐São Paulo Plateau System, SE Brazil

“…The formation of these wide (“sag”) offshore basin (as the SSPS) filled with quasihorizontal sedimentary layers on top of a continental basement cannot occur if considering a single hinge line and an abrupt thinning of the continental crust. This form of subsidence implies two hinge lines, one located at the beginning (top) and the other at the termination (bottom) of the necking zone [e.g., Leroux et al ., ].…”

Gondwana breakup: Messages from the North Natal Valley

“…Notwithstanding, to understand the genesis and evolution of continental passive margins we need to define their current and initial geometries, their crustal segmentation and its nature by combining high‐quality multichannel (MCS) and wide‐angle seismic data. We also need to determine the exact conjugate margin system and its tightest initial position and constrain horizontal and vertical motions (subsidence) by studying the overlying sedimentary sequences with a focus on palaeo‐environments and stratigraphic sequences (for instance, Leroux et al, ).…”

The Minorca Basin: a buffer zone between the Valencia and Liguro‐Provençal Basins (NW Mediterranean Sea)

“…Two NW – SE‐ oriented boundaries delineate the Minorca basin ( CFZ : Central Fracture Zone; NBFZ : North Balearic Fracture Zone). Hinge lines highlighted in the Liguro‐Provençal basin show the main boundaries in the crustal evolution and subsidence response (from Leroux et al ., ; Moulin et al ., ). Cartography of the atypical oceanic crust results from a compilation of gravimetric, magnetic and velocity responses (e.g.…”

“…While both VBss and LPB segments (Leroux et al ., ) exhibit pure vertical subsidence (Fig. B), the thinning process may not be the same, as VBss is a polyphased basin, and the LPB thinning occurred only during the Neogene due to the exhumation of the lower CC.…”