Abstract Carbonate platforms can have complex internal facies variations and stratal geometries expressed at length scales longer than all but the largest outcrops. The latter commonly form high and relatively inaccessible cliffs, and thus conventional field techniques (logging and photomontages) may not adequately capture the 3D geometry of surfaces and the details of the facies distribution. Because facies and stratal geometry control rock properties and connectivity in carbonate reservoirs, accurate outcrop data can be critical to reservoir and forward seismic modeling. The Gresse-en-Vercors cliffs (southeastern France) provide a seismic-scale slice though a Lower Cretaceous (Barremian) platform margin analogous to Lower Cretaceous reservoirs in the Middle East. The cliffs are 500 m high and extend for 25 km along depositional dip, straddling the transition from shallow-water platform to deeper basin. This paper describes the methodology developed to create a high-resolution stratigraphical digital outcrop model (DOM) integrating field measurements (logged sections, facies mapping) and high-resolution digital data (photomosaic and new LIDAR data acquired by a helicopter survey). Integration of the LIDAR and other point cloud data provide a high-resolution digital elevation model (DEM) on which georeferenced field observations were then posted. The “solid image” technique was used to extract precise x,y,z coordinates of stratigraphic surfaces from the DEM. The resulting numerical geological model allows a coherent restoration of the platform architecture, quantification of component surfaces (shape, angles, dimensions) and geobodies, and a better characterization of the relationship between facies and platform architecture

Abstract: The trace-element content and strontium isotope ratio have been determined for twelve requienid rudists from SE France. Fromthese data the seawater ratio of eight stratigraphic intervals was determined. The biostratigraphy of the associated platform carbonates, ranging from Berriasian to Lower Aptian, was derived from shallow-water benthic organisms, including calcareous algae (Dasycladales), large foraminifera (mainly Orbitolinidae), and rudists. Isotope ratios of well preserved rudist shells were compared to secular variationsof the 87 Sr/ 86 Sr ratio of seawater as derived from belemnites and calibrated to the Boreal ammonite zonation ( McArthur et al., 2001 ).Stratigraphic mismatches between the values measured on requieniid rudists and the Boreal Sr-isotope reference curve appear to resultmainly from the fact that the reference curve is resolved rather as a band. A few larger discrepancies may be due to weaknesses in the original correlation of biostratigraphic markers and isotope values for some time intervals (e.g., upper Barremian).

Abstract: Based on material collected in Lower Albian beds from Baja California, the revision of “Petalodontia” felixi and “Horiopleura” gregaria shows that the former must be assigned to a new genus Pseudopetalodontia (Monopleuridae) and the latter has to be transferred tothe genus Tepeyacia (Polyconitidae). These two taxa belong to the “Coalcomana ramosa fauna” of Early Albian age and are widely distributedin the Guerrero Terrane and the Gulf of Mexico. Horiopleura and Petalodontia appear to be restricted to the Old World, whereas Pseudopetalodontia nov. gen. and Tepeyacia are confined to the New World.

Abstract The diversity of rudists In the Lower Cretaceous of Arabia offers great potential both for biostratigraphical correlation (particularly of certain key levels, such as the Lower/Upper Aptian boundary) and for facies analysis. With the aim of raising awareness of this potential among geologists working on core and outcrop material, we provide here synoptic diagnoses of the seventeen species (at least) so far recognized, together with comments on their stratigraphical distributions and paleoecology, and a range chart.

Abstract Cretaceous carbonate platforms are some of the largest and most widespread sedimentary units in the geologic column. They developed throughout the Cretaceous Period in the Tethyan region. Furthermore, they have yielded significant amounts of the world's oil production and contain major reserves (Scott et al., Chapter 2, this volume). Cretaceous platforms contain important information about changes in fauna, depositional facies, diagenesis, and climatic events, and they provide clues to platform growth and demise. Comparison of different carbonate platforms from diverse tectonic and climatic settings provides a unique test to constrain basic controls on carbonate platform evolution, including effects of biotic changes, eustatic sea level fluctuations, variations in tectonic subsidence rates, terrigenous sediment influx, paleoclimates, and long- and short-term accretion and demise of carbonate platforms. This volume is designed to present examples and provide stratigraphic and depositional data on several Cretaceous carbonate platforms around the world for comparative purposes.

Abstract Cretaceous carbonate platforms have great economic significance to humans and our quality of life. They contain approximately 16 of the world's hydrocarbon reserves (Carmatt and St. John, 1986; Klemme and Ulmishek, 1991). In addition, Cretaceous carbonates contain significant bauxite deposits (for aluminum), sedimentary iron, phosphate ores, and important secondary mineral deposits. Cretaceous carbonates are important sources of marble, building stone, and lime for construction. At many places in the world, Cretaceous carbonate platforms have played a significant role in the course of human history not only as economic resources but also as landforms that have influenced human actions.

Abstract Name of platform: Maracaibo platform Authors: Volker C. Vahrenkamp, R. C. W. M. Franssen, J. Grötsch, and P. J. Munoz Location: From 70° to 73° east longitude and 8° to 11° north latitude, northwestern Venezuela Geologic time interval: Early Aptian to late Albian Tectonic-sedimentary setting: Abandoned Jurassic rift graben at the passive margin of the South American craton (Guyana shield) Basin type: Abandoned rift sag on passive continental margin Paleoclimate: Humid tropical Platform type: Distally steepened(?) ramp with localized shoals Platform geometry: Less than 100 m thick in the southeast and more than 370 m thick in the northwest. The extent of shallow water carbonate deposition reached more than 180 km (southeast-northwest) by 450 km (southwest-northeast) Facies and fossils: Siliciclastic siltstone, mangrove peat, dolomitic oyster boundstone, milliolid wackestone, orbitolina wackestone–packstone, bioclastic and bioturbated grainstone–packstone, cross-bedded bioclastic and oolitic grainstone Systems tracts: Trangressive system tracts: shallow marine, high energy, open platform packstone and grainstone. Highstand system tracts: mixed carbonate–siliciclastic, low energy, shallow marine lagoonal deposits. Lowstand system tract: not documented. A shift of shallow water carbonates into slope and basinal settings to the west (Machiques trough) and probably to the north of the study area is likely but has not been observed. Stacking patterns: Initial transgression upon basal siliciclastics; as many as six large-scale (third-order) laterally correlated transgressive—regressive cycles; numerous smaller scale (fourth- and fifth-order?) shallowing upward cycles; upper boundary well defined by drowning surface overlain by regionally extensive deep marine carbonates of the latest Albian–Cenomanian La Luna Formation.The Maracaib oplatform

Abstract Names: Cupido and Aurora around Coahuila block, Golden Lane (Tuxpan), and Valles–San Luis Potosí platforms Authors: J. L. Wilson and W. C. Ward Location: From 96° to 102° west longitude and 20° to 28° north latitude, northeastern and east-central Mexico Geologic time interval: Two periods of platform development: Neocomian–Aptian and Albian-Cenomanian, separated by a transgressive shale Tectonic-sedimentary setting: Rifted and dissected passive margin Basin type: Marginal cratonic Paleoclimate: Semitropical, generally humid but with two semi-arid periods in early Aptian and middle Albian Platform type: Rimmed shelves around major positive basement blocks and isolated platforms developed over positive blocks Platform geometry: Thickness of a few hundred meters to 2000 m. Rimmed shelves as much as 80 km wide and hundreds of km long. Isolated platforms are 65 by 145 km and 200 by 300 km Facies and fossils: Multitextured carbonates, minor amounts of terrigenous clastics. Both extensive pelagic biotas and shallow water benthos of foraminifers, algae, corals, and various molluscs, particularly rudists. Systems tracts: Sabkha evaporites, intertidal carbonate cycles, grainstone shoals, coarse rudist–coral–sponge–hydrozoan–red algae at shelf margin, lithoclastic debris, pelagic rhythmites in basin. Mostly highstand systems tracts leading into starved basins. Only minor lowstand systems tracts. Stacking patterns: Progradations of simple sigmoid sequences, some rising in the sequence as they prograde (Barremian–Aptian). Some of the Albian-Cenomanian platforms are predominantly aggradational, although progradational sequences are documented on the southeastern margin of the Valles platform and the southern flank of the Coahuila block.

Abstract Name: Valles-San Luis Potosi platform Authors: M. A. Basáñez-Loyola, R. Fernandez-Turner, and C. Rosales-Domínguez Location: From 98° 50' to 101° west longitude and 21° 15' to 23° 45' north latitude, states of San Luis Potosi, Guanajuato, Queretaro, and Nuevo Leon, northeastern central Mexico Geologic time interval: Valanginian–early Senonian Tectonic-sedimentary setting: Rifted passive margin Basin type: Epeiric shelf, marginal cratonic Paleoclimate: Humid and tropical Platform type: Isolated Platform geometry: 2500 m thick; 200 km wide, approximately 235 km long Facies and fossils: Fine- to coarse-grained carbonates; benthic foraminifera, mainly miliolida, molluscs (rudists), algae, and corals Systems tracts: Evaporitic lagoon, lagoon, organic reefs, foreslope, basin at highstand systems tract Stacking patterns: Progradational lagoon and reefal edge, before drowning and final retrogradation

Abstract Name: Chihuahua basin Author: Carlos M. Cantú Chapa Location: From 103° 30' to 105° 00' west longitude and 28° 30' to 29° 45' north latitude, state of Chihuahua, Mexico Geologic time interval: Albian-Cenomanian Tectonic-sedimentary setting: Intracontinental rifting Basin type: Epicontinental shelf Paleoclimate: Generally humid, semitropical Platform type: Ramp Platform geometry: 1250 m thick, at least 200 km wide, and about 300 km long Facies and fossils: Thick carbonates with levels of clay-rich limestones, minor amounts of shales and sandstones; benthonic and planktonic microfossils, ammonites, pelecypods, and echinoderms Systems tracks: Transgressive to regressive, composed of intertidal to subtidal, inner shelf and outer shelf Stacking patterns: Combinations of retrogradational (or transgressive) followed by progradational (or regressive) successions

Abstract Name: Mural carbonate shelf Authors: R. W. Scott and E. R. Warzeski Location: From 109° to 110° 30° west longitude and 31° to 32° north latitude, Arizona and Sonora Geologic time interval: Early Cretaceous, Barremian–Albian Tectonic-sedimentary setting: Back-arc basin evolved from a Jurassic thermotectonic rift basin Basin type: Epeiric shelf Paleoclimate: Generally humid, semitropical Platform type: Ramp Platform geometry: 240 m thick; at least 55 km wide; approximately 800 km long Facies and fossils: Fine to coarse carbonates, minor amounts of shale and sandstone; pelagic and benthic foraminifers, algae, molluscs, and corals Systems tracts: Transgressive, aggradational to progradational composed of lacustrine, fluvial, deltaic, lagoon, shelf margin, and basinal depositional systems Stacking patterns: Progradational simple sigmoid parasequences