Abstract Muleshoe Mound is a composite Waulsortian buildup that forms a distinctive promontory along the western escarpment of the Sacramento Mountains (New Mexico, U.S.A.). Excellent exposures allow detailed study of the mound's fades, paleontology, geometry, internal architecture, and off mound stratal relationships. Recent work suggests that many Waulsortian mounds may have originated and grown in more agitated, shallower water environments than previously thought. The previously 'enigmatic' character of these Lower Carboniferous buildups may largely be due to differences in basin stratification, oxygen and possibly nutrient levels. Muleshoe Mound can be separated into at least five distinct stratal packages or 'growth phases'. Successive growth phases differ in fades, geometry, and symmetry, reflecting different environmental conditions (energy, carbonate production, oxygenation and accommodation space). Intervening surfaces represent periods of hiatus and erosion. The architecture of this mound growth phase pattern strongly suggests that accommodation space was a critical control on mound growth. Field study, serial slabbing, and petrographic examination of the mound facies indicate that Muleshoe grew in appreciable currents and intermittent high energy. Much of the micrite in the buildup originated as a microbial precipitation within an organic (algal?) host, rather than as depositional carbonate mud. This process of microbial precipitation, combined with extensive marine cementation, built the mounds' depositional relief and created a relatively rigid growth framework. These features appear to conflict with the common interpretation of Waulsortian mounds as deep, quiet water buildups and Muleshoe may have formed in depths and energy conditions not dissimilar to many modern reefs. These features are not unique to Muleshoe, but occur in many Waulsortian mound suites. Differences between these ancient buildups and modern reefs suggest the modern ocean is an imperfect model for Early Carboniferous seas.

Abstract The Guadalupe and Hueco Mountains are exquisite natural laboratories for studying the stratigraphy, depositional facies, and diagenetic overprint of Permian platform and reef carbonates. Well-studied outcrops from these two classic localities serve as important analogs for other areas where the data is more limited. In addition, studies from the two areas have had immediate application to subsurface hydrocarbon exploration and exploitation efforts in the immediately adjacent Permian Basin. Our field trip of three days will emphasize the stratigraphic framework, facies, and diagenesis of a Lower Permian (Wolfcampian) low-relief carbonate platform outcropping in the Hueco Mountains and an Upper Permian (Guadalupian) steep-rimmed platform of the Guadalupe Mountains. We invite questions and discussion at all field stops, as our group has diverse backgrounds and interests and any discussion will be beneficial to all. The focus of the trip in the Hueco Mountains is on the evolution of the shelf-margin architecture and fauna! change. The exposures allow us to view the architectural elements of a prograding and retrograding shelf margin in ice-house conditions as well as the biotic response to environmental change. A relevant part of the exposure to visit is the facies variability both temporally and laterally. Our emphasis in the Guadalupe Mountains is on the Capitan margin, as well as the related shelf and basin deposits. Large-scale outcrops like that of McKittrick Canyon offer an unparalleled view into the inside of a progradational platform, and we hope you will agree that the hike up the Permian Reef Geology Trail presents an

Abstract J. A. (Tom) Simo, Greg P. Wahlman, Michelle L. Stoklosa, Jen L. Beall The Permian was a remarkable geological period, and it is reflected in the abundance of important sedimentary mineral resources. It represents the maximum stage of Pangeacontinental accretion, a gigantic continent from pole to pole surrounded by an all-encompassing ocean. The large Permsylvanian-Lower Permian Gondwana polar ice cap was at its maximum and later was partially replaced by large lakes. Chemically, Permian seas reached the most extreme values of carbon, sulfur, and strontium isotopic ratios, but returned abruptly to normal values close to the end of the Permian period ( Scholle et al. , 1995 ). Fauna and flora show an increasing provincialism that culminated at the end of the Permian with one of the largest extinction events in Earth’s history. The Permian rocks reflect those extreme physical, chemical, and biologic changes. As such, the Permian sedimentary record is unique to explain changes in the biosphere, and the occurrence and distribution of economic deposits. For instance, from early to late Permian, source bed accumulation shifted from a period of major to minor occurrences respectively. The abundance of carbon in the sedimentary record is in part the reason of large early-middle Permian in age reserves of oil and gas (minimum global estimates are 28.4 MMM13 of oil and 6642 TCF of gas; Mazzullo, 1995 ). Similarly, the global cycle of phosphorous followed that of carbon (phosphorite deposits are early to middle Permian; Herring, 1995 ). The high carbon

Abstract The Late Permian (Guadalupian) mixed carbonate/siliciclastic sequences of the Delaware Basin, one of the long-lived subbasins of the Permian Basin, are well knovvn both for their classic outcrop exposures revealed by basin and range structuring in the Guadalupe Mountains and for their prolific hydrocarbon production (Figure 18 ). A large number of stratigraphic and sedimentologic studies have established the Capitan reef and associated facies as a model for the understanding of carbonate facies in a shelf margin setting and of reciprocal sedimentation relations between a shelf and basin. Early studies focused on biostratigraphy, lithostratigraphy, and early concepts of reciprocal sedimentation. Focus shifted in the 1970’s and 1980’s to analysis of depositional facies and processes and on the relatively new understanding of early diagenesis of reef margins. More recently, the outcrops have been analyzed from a cyclostratigraphy and sequence stratigraphy perspective. It will be interesting to see the impact of a refined stratigraphic fi-amework on the direction of future facies, paleo-ecological, and diagenetic studies. Providing the initial interest in the area were the superb field studies and subsequent detailed reporting of the geology of the southern Guadalupe Mountains by King (1942, 1948 ). The book by Newell et al. (1953) on the Capitan did much to further enhance the outcrops as research models for sedimentary geologists. The critical treatment of the Capitan sedimentology by Dunham in the late 1950’s and 1960’s, culminating in his detailed 1972 guidebook, stimulated interest and added new understanding. Dunham’s work, plus the

Abstract During our few days in the field we observed and compared two Permian carbonate platforms deposited in different paleogeographic settings, paleoclimatic modes and tectonic settings. The Lower Permian, Wolfcampian, strata represent the basin fill of the Orogrande Basin and the platform studied forms the leeward side of the Diablo Platform. These deposits followed a major tectonic re-organization of the area and formation of the “Mid-Wolfcampian” unconformity. The Upper Permian, Guadalupian, represents the basin fill of the Delaware Basin in a “near” windward position following a time of tectonic quiescence. The Lower Permian was a time of major continental glaciation, thus with major glacio-eustatic sea level changes and a humid climate. In contrast, the Guadalupian was a transition from ice- to hot-house conditions and an arid climate. The paleoclimatic conditions impacted some of the architectural elements of the platform. For instance, the decrease in the amplitude of sea level change through the Permian can be seen in the expression of the sequence boundaries and the amount of shelf-margin exposure. The Wolfcampian margin and slope was often exposed to subaerial conditions and the Guadalupian reef-margin was mostly submerged. Additionally, the more arid conditions in the Guadalupian favored the expansion of eolian ergs and the delivery of siliciclastics to the shelf and basin. ‘Thus, cyclicity is well marked by the influx of siliciclastics. The nature of the relationship between reef biota, paleoecology, and paleoclimate change is still unclear. However, there is a parallelism between tectonic and paleoclimatic changes and evolution of the Permian

Abstract Permian Platforms and Reefs in the Guadalupe and Hueco Mountains - The Guadalupe and Hueco Mountains are exquisite natural laboratories for studying the stratigraphy, depositional facies, and diagenetic overprint of Permian platform and reef carbonates. SEPM Field Guide No. 9 emphasizes the stratigraphic framework, facies, and diagenesis of a Lower Permian (Wolfcampian) low-relief carbonate platform outcropping in the Hueco Mountains. It also emphasizes an Upper Permian (Guadalupian) steep-rimmed platform of the Guadalupe Mountains. This successful three-day trip stemmed for a 2000 joint SEPM/IAS Research Conference entitled Permo- Carboniferous Carbonate Platforms and Reefs based in El Paso, Texas.

Abstract The SEPM Research Symposium for the 1997 AAPG–SEPM Annual Meeting in Dallas, Texas, was organized around the theme "Advances in Carbonate Sequence Stratigraphy—Application to Reservoirs, Outcrops, and Models." The symposium consisted of both oral and poster presentations. The sessions proved to be thought-provoking and forward-looking and showed how sequence stratigraphy is influencing many aspects in our understanding of carbonates. The very favorable response to the symposium encouraged many of the authors to publish their material and led to this SEPM Special Publication.

Abstract The Middle to Upper Ordovician Decorah and Galena Formations in Wisconsin are composed of stratigraphically condensed sequences(net accumulation rate : 0.35--0.9 cm/k .y., characterized by extreme lateral cont inuity of facie s and dominated by fine-grained carbonate with numer ousomission surfaces. Depositional sequences are defined by relatively conformable successions bounded by identified or interpreted exposure surfaces across which siliciclastics and skeletal grains increase abruptly. Depositional sequences are subdivided in a nested hierarchy into cycle sets,cycles, and omission-surface-bounded packages. The lower sequence, sequence D, corresponds to the Decorah Formation and has a siliciclastic-rich fining-upward succession followed by a coarsening-upward carbonate succession. The phosphate-enriched condensed section above the fining-upward succession represents maximum transgression .Cycles in seq uence D are represented by the upward increases in ske letal-grain and tempestite abundance. The middle sequence, sequence G 1, corresponds to the Galena Formation (lower to middle Dunleith Member) and shows an overall transition from a shale- and skeletal-grain-rich base to a carbonate-mud-dominated top. Both shale content and the abundance of skel etal-grain-supported rocks increase northward in eastern Wisconsin and westward in southern Wisconsin toward the inferred paleoshore line. The upper sequence, sequence G2, corresponds to the Galena Formation (upper part of Dunleith, Wise Lake, and Dubuque Members) and consists of a skeletal-grain-rich base with minor shale content grading upward into mudstones and into a skeletal-grain-rich top. Cycle sets and cycles in the sequences G I and G2 are characterized by relatively sharp boundaries across which there is an abrupt increase in shale content and skeletal-grain-rich facies grading upward to a carbonate-mud-dominated facies. The asymmetry of cycles-represented by the abrupt increase followed by gradual decrease in shale content and skeletal grains-is incon sistent with progradation of high-energy shale-rich facies over low-energy mudstone. This facies stacking pattern is better explained by reciprocal sedimentation in which skeletal-grain-rich shale deposition and carbonate-mud deposition are disassociated from each other both in time and space. The omission-surface-bounded pack ages form the smallest recognized sedimentary units within the sequences Gland G2 and represent alternations of periods of sediment deposition and starvation. The Decorah and Galena Formations are dominated by mudstone-rich lithofacies and abundant omission surfaces, and their contained fauna consists predominantly of heterotrophs. These characteristics are in contrast with tho se of the Lower Ordovician and Silurian "Bahama-like" carbonate strata. Apparently, in addition to tectonics, antecedent topography, and changes in eu stasy, siliciclastic influx, and storm transport, the paleoclimatic and paleoceanographic conditions in the Late Ordovician epeiric sea had important controls on depositional models, sequence development, and facies stacking patterns.

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.