A new titanosaur, Atsinganosaurus velauciensis, gen. and sp. nov. is described from well-preserved remains from the new Upper Cretaceous locality of Velaux-La Bastide Neuve (Aix-en-Provence Basin, France). This taxon is mainly diagnosed by a combination of characters, which differentiates it without ambiguity from other European Late Cretaceous taxa (Lirainosaurus, Ampelosaurus and Magyarosaurus). Atsinganosaurus confirms the presence in western Europe during the latest Cretaceous of a third titanosaurian species, slender and less derived which allows us to better understand the evolutionary and paleobiogeographical history of this group during the Cretaceous.

We investigated the effect of porosity, pore geometry, and diagenetic history on the elastic properties of dry, tightly cemented grainstones whose pore space consists dominantly of intragranular microporosity within micritic grains. The integration of laboratory petrophysical measurements (porosity, P- and S-wave velocity), petrographic analysis and scanning electron microscope (SEM) imaging of micropore space of 80 Lower Cretaceous microporous carbonate samples from Provence (south-east France) allows (1) the changes in porosity and pore geometry during the diagenetic history to be related to changes in elastic properties, and (2) the impact of micritic grain diagenesis on the elastic properties of microporous grainstones to be quantified by means of fitting parameters derived from equivalent elastic medium modeling. The Urgonian microporous cemented grainstones are elastically equivalent to a homogeneous calcitic host with spherical calcitic inclusions comprising spheroidal pores. The best fit is obtained when porous spheres are modelled using the differential effective medium (DEM) approach and the whole composite using the self-consistent (SC) method (DEM-SC model). At lower porosity values (<20%), when the micropore volume is controlled by intercrystalline cementation processes without compaction, the equivalent pore aspect ratio (EPAR) derived from DEM-SC modelling is nearly constant and averages 0.15. At higher porosities, changes in micropore space architecture related to leaching processes result in slightly increasing EPAR. The recognition of EPAR-preserving versus EPAR-non preserving elastic property evolution is proposed as a tool for diagenetic pattern detection in microporous carbonate reservoirs.

By integrating elastic-property measurements and quantitative mineralogic and petrographic analyses of 45 mixed carbonate-siliciclastic samples from two wells drilled in Late Cretaceous rock of the South Provence Basin (southeast France), we can (1) identify and quantify the parameters controlling elastic properties; (2) demonstrate that micrite can be considered as a porous medium with a low critical porosity, averaging 18%; and (3) relate diagenetic transformations, pore-structure modifications, and elastic-property changes. Microporous carbonates with compact anhedral and euhedral microrhombic micrites display a steeper decrease in compressional and shear velocities with increasing porosity than do carbonate rocks with moldic, intergranular, or intercrystalline macroporosity. The low value of critical porosity estimated in micrites (18%), as well as the steep slopes of velocity-porosity relationships at low porosity, is believed to result from a pore-network geometry characterized by very flat, thin pores bounded by planar faces of micrite crystals. Cementation of microrhombic micrite steeply increases elastic moduli, whereas dissolution processes significantly increase porosity with low variations of elastic moduli. Thus, critical-porosity concepts can help describe and model elastic properties of micritic microporous carbonate.

New high-quality multibeam and seismic data image the western slope of the Great Bahama Bank and the adjacent floor of the Straits of Florida. The extensive survey reveals several unexpected large- and small-scale morphologies. These include bypass areas, channel-leveelobe systems, gullied slopes, and products of slope instabilities at various scales, including long slump scars at the lower slope and mass transport complexes that extend ~30 km into the adjacent basin floor. The toe of the slope is irregularly covered with deep-water carbonate mounds. The abundance of the individual morphological features varies from north to south. From 26°00'N to 25°20'N, the slope is dissected by numerous deep canyons that abruptly end southward, where the slope is characterized by a smooth lower portion and small regularly spaced furrows in its upper part. Further south, two long (25-50 km) scars document instability at the lower slope. One of these scars is the source area of a large mass transport complex. In addition to this large-scale feature, several types of gravity-induced sedimentary processes are revealed. Most of the morphologies and inferred processes of this carbonate system are similar to those observed in siliciclastic systems, including mass transport complexes, gravity currents initiated by density cascading, and overspilling channeled turbidity currents. For the first time, a clear asymmetric channel-levee system has been identified along the slope, suggesting similitude in sorting processes between carbonate and siliciclastic systems and enhancing the reservoir-bearing potential of carbonate slopes. Notable differences with siliciclastic systems include: the lack of connection with the shallow and emerged part of the system (i.e., bank top), and the small size of the sedimentary system. © 2012 Geological Society of America