Carbonate Platform

ABSTRACTRecent work has improved understanding of the benthic foraminiferal stratigraphic and palaeoenvironmental ranges of the Middle to Upper Jurassic reservoir-containing carbonates of Saudi Arabia. The entire Jurassic succession includes the Marrat, Dhruma, Tuwaiq Mountain, Hanifa, Jubaila and Arab formations that terminate with a succession of evaporites, the final, thickest unit of which is termed the Hith Formation. This study focuses on selected carbonate members studied from the Dhruma Formation and above, and includes the Lower Fadhili, Upper Fadhili, Hanifa and Arab-D reservoirs. The Hadriya and Manifa reservoirs are not considered. An ascending order of tiered deep-to shallow-marine foraminiferal assemblages has been determined for each formation and applied to distinguish both long- and short-term palaeobathymetric variations. The Lenticulina-Nodosaria-spicule dominated assemblage characterises the deepest mud-dominated successions in all formations. The consistent pres...

Several dinosaur footprints were discovered on three different levels cropping out in the CO.L.MAR quarry, south of the village of Borgo Celano in the Gargano Promontory (Apulia, southern Italy). The track-bearing levels belong to a carbonate inner platform succession referred to the Lower Cretaceous (upper Hauterivian-lower Barremian). This paper describes only the lowest dinoturbated bed, where footprints are preserved as natural cast. Forty footprints, mostly tridactyl, have been attributed to medium-sized theropods. Tridactyl tracks are similar to Kayentapus Welles, 1971 regarding ichnotaxonomy. Round shaped footprints, previously not described from this site, are found in association with tridactyl footprints and are related to ornitischian dinosaurs.

The Apulian marine carbonate Platform, an unusual environment for terrestrial animals, has revealed a diverse ichnological record, especially for dinosaurs. Members of most higher taxa are present, including sauropods, theropods, ankylosaurs and ornithopods. Recently, a small outcrop of Aptian age referred to the Calcare di Bari near Bisceglie (Bari) has yielded a new quadrupedal trackway that we attribute to Ankylosauria. This new find enhances the record of Cretaceous ankylosaur footprints from the Apulian carbonate Platform, previously known from another site near Bisceglie (early Aptian), from Borgo Celano (late Hauterivianeearly Barremian), and from Altamura (late Coniacianeearly Santonian).

En la Cordillera Ibérica (Rama Castellana), entre los depósitos de facies Keuper y las «Carniolas», se sitúa una unidad dolomítica que ha sido definida recientemente como formación Dolomías tableadas de Imán (Gor, GÓ-MEZ y YÉBENES, ni litt.). En el presente trabajo se hace un detallado estudio del corte tipo y se describen varios afloramientos de la Cordillera Ibérica y región manchega. Asimismo, se establecen relaciones existentes con otras zonas periféricas. Los datos paleontológicos, aunque son escasos, permiten atribuir a estas dolomías una edad Triásico superior terminal. Dans la Cordillére Ibérique (Branche Castillans), entre les depóts de faciés Keuper et les «Carniolas» se trouve située une unité dolomitique qu a éte définie récentement comme formation Dolomias litées d'Imon (GoY, GÓ-MEZ y YÉBENES, lii ¡itt.). La présente note comporte une étude détailíde du coupe type et différents affleurernents de la Cordillére Ibérique et de la region manchega y sont étudies. De méme, les rapports existants avec d'autres zones périphériques sont ¿tablis. Les rares données paléontologiques permettent d'attribuer á ces dolomies un ñge Triassique supéricure terminal. La formación Dolomías tableadas de Imán ha sido definida recientemente en la Cordillera Ibérica (Rama Castellana) por Gor, GÓMEZ y YÉBENES (in ¡itt.). Yace concordante sobre las margas yesíferas del Keuper, de las que está

Based on new field work, sampling for conodonts, ammonoids, and microfacies analysis, the Lower to Upper Devonian stratigraphy of the Benahmed region is refined. Fossiliferous neritic limestones of the Pragian/lower Emsian represent a continuation of the shallow carbonate platform of the Al Attamna region to the north (Units A/B of Sidi Ahmed Lemdoun Formation). More argillaceous upper Emsian/Eifelian strata are regionally still poorly known. In the southern Chaouїa or Beni Sekten region NW of Benahmed, Givetian deep neritic to shallow pelagic mud-wackestones of the new Oulad Amar Formation were partly reworked and re-sedimented together with crinoidal grainstones in conglomeratic debris flow beds. Peaks of Eovariscan block faulting and reworking occurred high in the middle (ansatus Zone) and at the top of the Givetian (norrisi Zone). Lower/middle Frasnian strata are still unknown in outcrop but limestones with corals of possible Givetian/Frasnian age have been reported from E/SE of...

The long-known Devonian of the Jebel Ardouz west of Marrakesh, and just north of Mzoudia, is composed of an allochthonous stack of clastic and carbonate rocks that were thrusted onto each other from the northeast. New biostratigraphic data prove an age range of sedimentation from the lower Eifelian to ?upper Famennian. The lowest, western thrust unit is composed of reddish sandstones and conglomerates/breccias (new Ardouz Formation) deposited originally by rockfall and debris flows on the slope of a repeatedly active fault scarp. Limestone clasts yielded sandstones of unknown age, Eifelian, Givetian and lower/middle Frasnian conodonts, and encrusted reef corals. Re-sedimentation may have occurred in the upper Frasnian or post-dated the Famennian. The "red conglomerates" record a block that was strongly tilted by Eovariscan extensional tectonics, forming on the uplifted side a small island. Exhumation, erosion down into Eifelian carbonates, and a long phase of reworking (pe...

afte d.d., E ploratio "e tor, Lovi čićeva 4, HR-10000 Zagreb, Croatia. We disagree with many of the concerns raised by Font et al., (submitted) and take this opportunity to clarify matters. We wish to emphasise that in our paper (Korbar et al., 2017), as well as in the first report on the pote tial Cretaceous-Palaeogene (K-Pg) tsunami in Adriatic region , we reported on rare shallow marine distal K-Pg records that differ from dominantly deep marine records commonly reported in other papers. We did not include more references on the latter, since that was not a goal of our paper and we encourage the authors of the Comment themselves to make additional research of the Likva section, especially the issues that are criticised.

Kor b ar, T., M o n t a n a ri, A., F u c e k, V. P., F u c e k, L., Co c cio ni, R., M c Do n al d, I ai n , Cl a ey s, P., S c h ulz, T. a n d Koe b e rl, C. 2 0 1 5. Po t e n ti al C r e t a c e o u s-P al e o g e n e b o u n d a r y t s u n a m i d e p o si t in t h e in t r a-Tet hy a n Ad ri a tic c a r b o n a t e pl a tfo r m s e c tio n of H v a r (C r o a ti a). G e olo gic al S o ci e ty of Am e ric a Bull e ti n 1 2 7 (1 1) ,

Abstract. This paper discusses the palaeoenvironmental significance of the "Orbitolina Level", the microbial carbonates and the Salpingoporella dinarica-rich deposits encased in the Aptian/Albian shallow water carbonate platform strata of Monte Tobenna and Monte Faito (Southern Italy). These facies show a peculiar field appearance due to their color and/or fossil content. In the shallow water carbonate strata, the Late Aptian "Orbitolina Level" was formed during a period of decreasing accommodation space. Microbial carbonates occur in different levels in the composite section. They reach their maximum thickness around the sequence boundaries just above the "Orbitolina Level" and close to the Aptian–Albian transition, and were not deposited during maximum flooding. S. dinarica-rich deposits occur in the lower part of the Monte Tobenna-Monte Faito composite section, in both restricted and more open lagoonal sediments. S. dinarica has its maximum abundance below the "Orbitolina Level" ...

A protocol for the determination of the concentration of selected elements in two rudist shells was developed using Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS). Element analysis in rudists has never been performed beyond including major and some minor elements, and thus this work presents the first results in this field. The concentrations of 35 isotopes were analyzed. Low iron and manganese concentrations reflect the absence of a diagenetical imprint on both shells. There is a negligible amount of crust-associated elements, which reveal little evidence of terrigenous input. Phosphorus amount is also low; however, it is high enough to mask reliable Rare Earth + Yttrium (REY) pattern measurements. Strontium and magnesium concentrations in the inner layers of a shell of Titanosarcolites show relicts of an original aragonitic composition. On the contrary, concentrations of these elements in a shell of Biradiolites rudissimus reveal an original low Mg-calcite mineralogy in its outer layers. The two shells were selected, considering their apparently a priori good preservation, based on the petrological examination of thin sections. No significant concentrations of elements such as chromium, cobalt, nickel, copper, zinc, molybdenum or antimony could be found. The concentrations of vanadium and barium may reflect evidence of biological activity, since they apparently do not correlate significantly with silicon, aluminium or sulphur. The low cost and precision of this method in comparison to others such as the use of electron microprobe, or X-ray fluorescence, makes it an optimum alternative for geochemical analyses of fossils, thus opening a new line of research.

Dark-grey cherty limestone from Mt. Svilaja contains moderately well-preserved radiolarians of unusually low diversity. Nineteen genera were encountered, namely, only one fourth of genera known from the time equivalent Buchenstein Formation. Based on conodonts, the studied interval is assigned to the Lower Ladinian Budurovignathus hungaricus Zone. Ammonoids and allochthonous fossil elements (calcareous algae, corals, brachiopods, bivalves, benthic foraminifera, terrestrial-plant remains) from the same interval were previously reported. Facies and organic-matter analyses support the interpretation of depositional setting in a semi-enclosed basin with oxygen-deficient bottom waters. The radiolarian assemblage consists of spherical Entactinaria (Pentactinocarpidae, Heptacladidae, Hindeosphaeridae) and Spumellaria ( Archaeocenosphaera, Paurinella, Triassospongosphaera, Spongopallium ), and monocyrtid Nassellaria (mostly Hozmadia ). Among Pentactinocarpidae, Lobactinocapsa ellipsoconcha Dumitrica is abundant and characterized by considerable variability of the cortical shell regarding its shape (ovoid to spherical), wall thickness (single-layered to spongy), and number of external spines. Eptingiidae, Oertlispongidae, Relindellidae, and all multicyrtid Nassellaria, common in the Buchenstein Formation as well as in radiolarian cherts associated with ophiolites, are missing. Similar, although less drastically reduced radiolarian fauna is known from the coeval San Giorgio Dolomite, which was also deposited in an oxygen-deficient intra-platform basin. The San Giorgio fauna lacks multicyrtid Nassellaria but still contains abundant Eptingiidae, Oertlispongidae, and Relindellidae. The likely factor reducing the diversity in the intra-platform basins was the vertical extent of the oxygen-deficient lower water column. Only surface-dwelling radiolarians were successful in stratified basins with expanded deep-water hypoxia.

During the early Toarcian, significant environmental perturbations in the biogeochemical cycles severely impacted marine and terrestrial ecosystems due to the release of greenhouse gases, the so-called Jenkyns Event. In order to document the impact of the Jenkyns Event in the northern Gondwana Palaeomargin, sedimentological, palaeontological, mineralogical and geochemical analyses of the Kef El Hassine section in central Tunisia were investigated. The lower-middle Toarcian of the studied section is composed of an alternation of marlstones and limestones with low total organic carbon deposited under hemipelagic conditions. Three phases have been differentiated that represent the conditions before, during and after the early Toarcian biotic crisis. Pre-biotic crisis is characterized by the presence of echinoderm plates, belemnite rostra and trace fossils (Arenicolites, Zoophycos, Thalassinoides and Chondrites), indicating oxic conditions in the sea-floor during the Polymorphum Zone related to the flooding of the earliest Jurassic carbonate platform. The early Toarcian biotic crisis (Levisoni Zone) begins with a negative carbon isotopic excursion (CIE) that characterizes the Jenkyns Event. The increase in detrital input and the presence of quartz and feldspar suggests an enhanced terrigenous influx during the negative CIE. The clay content and the kaolinite/illite ratio increases, reflecting intensified hydrological cycle and silicate weathering. The negative excursion in δ 18 O is interpreted as evidence of the early Toarcian climate warming. The development of a benthic barren interval, which includes most of the Levisoni Zone, points to adverse conditions in the sea bottom. The increase of redox sensitive elements points to oxygen depleted conditions in the bottom waters and in the sediment pore waters. The recovery phase post-biotic crisis is characterized by a decrease of redox sensitive elements, indicating an increase in the oxygenation levels of the bottom waters. Benthic foraminifera recolonization of the sea-floor is recorded, dominated by opportunist forms (Lenticulina and Reinholdella), confirming the progressive recovery of benthic ecosystems. The increasing quartz/clay ratio and decreasing kaolinite/illite ratio at the beginning of the Bifrons Zone indicate the installation of relatively arid conditions during the first steps of the recovery phase with a subsequent increase of weathering.

This paper presents the first comprehensive study of the Wordiekammen carbonate platform on the Nordfjorden High, Central Spitsbergen. The Wordiekammen succession is divided into four depositional sequences bounded by subaerial exposure surfaces and consists of 12-84 m-thick wedgeshaped sequences being thickest in the distal area and thinner on the crest of the High. The uppermost Finlayfjellet Beds (Tyrrellfjellet sequence 2) represents in contrast a uniform sequence. The Wordiekammen Formation is composed of 11 depositional carbonate facies and three overprint facies which are grouped into 10 facies associations. Each association represents a predictable pattern of facies, 0.5-22 m thick, which is repeated many times producing a distinct cyclicity in the succession. The Wordiekammen Formation is composed of 50 depositional cycles, 21 cycles in the Kapitol Member and 29 cycles in the Tyrrellfjellet Member. Analysis of the well-dated Tyrrellfjellet Member indicates that the succession was controlled by mixed 100 kyr and 400 kyr cyclicity signals which are believed to be a reflection of eustatic sea-level fluctuation and tectonic instability. Allocyclic control on the deposition dominated the majority of the Wordiekammen succession, and an abrupt change in depositional style in the uppermost Finlayfjellet Beds is believed to reflect the break-down of the Gondwanaland ice sheets and the end of glacio-eustaic control. Four key lithological intervals and unconformities have been correlated across the Billefjorden Fault Zone to the time-equivalent succession in Bünsow Land. Based on the correlation, it is considered that the distal part of the Nordfjorden High towards the west and the carbonate platform on Bünsow Land reflected a similar geological setting while the up-dip and crestal part of the Nordfjorden High was a positive feature that divided the two carbonate platforms during sea-level lows. Finally, it is believed that the Nordfjorden High remained a homoclinal carbonate ramp up to at least Late Asselian times.

This paper presents the first comprehensive study of the Wordiekammen carbonate platform on the Nordfjorden High, Central Spitsbergen. The Wordiekammen succession is divided into four depositional sequences bounded by subaerial exposure surfaces and consists of 12-84 m-thick wedgeshaped sequences being thickest in the distal area and thinner on the crest of the High. The uppermost Finlayfjellet Beds (Tyrrellfjellet sequence 2) represents in contrast a uniform sequence. The Wordiekammen Formation is composed of 11 depositional carbonate facies and three overprint facies which are grouped into 10 facies associations. Each association represents a predictable pattern of facies, 0.5-22 m thick, which is repeated many times producing a distinct cyclicity in the succession. The Wordiekammen Formation is composed of 50 depositional cycles, 21 cycles in the Kapitol Member and 29 cycles in the Tyrrellfjellet Member. Analysis of the well-dated Tyrrellfjellet Member indicates that the succession was controlled by mixed 100 kyr and 400 kyr cyclicity signals which are believed to be a reflection of eustatic sea-level fluctuation and tectonic instability. Allocyclic control on the deposition dominated the majority of the Wordiekammen succession, and an abrupt change in depositional style in the uppermost Finlayfjellet Beds is believed to reflect the break-down of the Gondwanaland ice sheets and the end of glacio-eustaic control. Four key lithological intervals and unconformities have been correlated across the Billefjorden Fault Zone to the time-equivalent succession in Bünsow Land. Based on the correlation, it is considered that the distal part of the Nordfjorden High towards the west and the carbonate platform on Bünsow Land reflected a similar geological setting while the up-dip and crestal part of the Nordfjorden High was a positive feature that divided the two carbonate platforms during sea-level lows. Finally, it is believed that the Nordfjorden High remained a homoclinal carbonate ramp up to at least Late Asselian times.

Southeastern Montenegro is the only part of the Adriatic Carbonate Platform (AdCP) that bears record of its evolution from a ramp, through a distally steepened ramp to a platform. In this paper we present the sequence stratigraphy of the Late Triassic to Late Jurassic rocks from this part of Tethys for the first time in the literature. We discovered and described three new facies: hardground and cerebroid oolites of the Livari Supersequence, and black pebble conglomerate of the Tejani Supersequence. The mid-ramp and lower ramp cherty oolite, wackestone and mudstone facies of the Livari Supersequence, as well as Oolite Conglomerate facies of the Stari Bar Supersequence were partially or completely reinterpreted. The Middle and Late Triassic rifting separated the AdCP from the other South Tethyan carbonate platforms and created the intraplatform Budva Basin. The AdCP evolved through three morphologic stages: a detached ramp (Livari Supersequence; Rhaetian-Early Toarcian), a distally steepened ramp (Tejani Supersequence; Early Toarcian-Middle Callovian) and an accretionary rimmed platform (Stari Bar Supersequence; Oxfordian to Neogene). The Rhaetian regression is marked by a regional unconformity surface that represents a type S sequence boundary at the base of the Livari Supersequence. Lowstand Wedge of the Halobia Limestone was the oldest sediment in the Budva Basin. TST and HST of the Livari Supersequence include: supratidal and intertidal inner ramp sediments, ooid shoals, and cyclic shallowing-up parasequences of the mid-ramp. Sedimentation rates were high in the inner ramp, while Budva Basin received relatively thin accumulation of siliceous plankton. A brief exposure of supratidal flats and ooid bars represents a type P sequence boundary between the Livari and the Tejani Supersequences, which was flooded by the Early Toarcian transgression. TST and HST of the Tejani Supersequence consist of supratidal, lagoon, and shoal sediments in the inner ramp, and deeper water carbonates of the mid-and outer ramp. Highstand shedding of the sediment from the steepened ramp left thick deposits in the Budva Basin. The Bathonian regression is marked by a regional unconformity that represents a type S sequence boundary between the Tejani and Stari Bar Supersequences. Stari Bar Oolite Conglomerate is a Lowstand Wedge of the Stari Bar Supersequence. The Middle Callovian transgression induced aggradation of ooid shoals deep into the platform interior. Oxfordian coral reefs created a rimmed platform and restricted export of the shallow carbonates into the Budva Basin.

The Upper Triassic (Carnian-Norian) Martin Bridge Formation of northeastern Oregon, southeastern Washington, and western Idaho is characterized by rapidly shifting depositional processes within a tropical volcanic island arc setting. Martin Bridge sequences in the Hells Canyon and northern Wallowa Mountains document shallow-water peritidal evaporitic sediments that are succeeded by deeper and predominantly subtidal deposits. This indicates drowning of the carbonate platform and a transition to deeper-water turbiditic sedimentation before a late Triassic transition into the overlying mid-Norian to Jurassic Hurwal Formation. At the type locality in the southern Wallowa Mountains, dysaerobic shales, carbonate debris sheets, and turbiditic sediments indicate distal slope and basinal environments while other facies at other sites in the Wallowa Mountains and Hells Canyon area s indicate reef and shallow-water platform settings. In this paper we formally recognize the name Martin Bridge Formation and reinstate the type locality in the southern Wallowa Mountains as the principal unit stratotype. An additional reference section is given at Hurricane Creek in the northern Wallowa Mountains. The Martin Bridge is formally divided into four members: the Eagle Creek and Summit Point Members are introduced and formally proposed herein and the BC Creek and Scotch Creek Members also are elevated to formal status. A partial reconstruction of the Wallowa terrane during deposition of the Martin Bridge Formation suggests a north-south (or northeast-southwest) trending platform margin facing a forearc basin situated to the east (or southeast). The lithofacies and paleontological characteristics of the Martin Bridge can be put into the framework of a deposition and a tectonic model to help better explain many of the stratigraphic and

Recent geological study of the Triassic from Albacete and eastern Prebetic allowed us to recognize on field and on well logs the five Keuper formations CK 1 to K 5 ) CORTI, F.; 1.974). This report is focused in the evaporitic K 1 , K 4 and K 5 .

High-resolution, time-significant correlations are integral to meaningful stratigraphic frameworks in depositional systems, but may be difficult to achieve using traditional sequence stratigraphic or biostratigraphic approaches alone, particularly in geologically complex settings. In steep, reefal carbonate margin-to-slope systems, such correlations are essential to unravel shelf-to-basin transitions, characterize strike variability, and develop predictive sequence stratigraphic modelsconcepts which are currently poorly understood in these heterogeneous settings. The Canning Basin Chronostratigraphy Project (CBCP) integrates multiple independent datasets (including biostratigraphy, magnetostratigraphy, stable isotope chemostratigraphy, and sequence stratigraphy) extracted from Upper Devonian (Frasnian and Famennian) reefal platform exposures along the Lennard Shelf, Canning Basin, Western Australia. These were used to generate a well-constrained stratigraphic framework and shelf-to-basin composite reconstruction of the carbonate system. The resultant integrated framework allows for unprecedented analysis of carbonate margin-to-slope heterogeneity, depositional architecture, and sequence stratigraphy along the Lennard Shelf. Systems tract architecture, facies partitioning, and stacking patterns of margin to lower-slope environments were assessed for six composite-scale sequences that form part of a transgressive-to-regressive supersequence and span the Frasnian-Famennian (F-F) biotic crisis. Variations are apparent in margin styles, foreslope facies proportions, dominant resedimentation processes, downslope contributing sediment factories, and vertical rock successions, related to hierarchical accommodation signals and ecological changes associated with F-F boundary. We present these results in the form of carbonate margin-to-basin sequence stratigraphic models and associations that link seismic-scale architecture to fine-scale facies heterogeneity. These models provide a predictive foundation for characterization of steep-sided flanks of reefal carbonate platform systems that is useful for both industry and academia. This study emphasizes the utility of an integrated stratigraphic approach and the insights gained from better-constrained facies and stratal architecture analysis; insights that were not achievable with traditional sequence stratigraphic or biostratigraphic techniques alone.

High-resolution, time-significant correlations are integral to meaningful stratigraphic frameworks in depositional systems but may be difficult to achieve using traditional sequence stratigraphic or biostratigraphic approaches alone, particularly in geologically complex settings. In steep, reefal carbonate margin-to-slope systems, such correlations are essential to unravel shelf-to-basin transitions, characterize strike variability, and develop predictive sequence stratigraphic models-concepts that are currently poorly understood in these heterogeneous settings. The Canning Basin Chronostratigraphy Project integrates multiple independent data sets (including biostratigraphy, magnetostratigraphy, stable isotope chemostratigraphy, and sequence stratigraphy) extracted from Upper Devonian (Frasnian and Famennian) reefal platform exposures along the Lennard Shelf, Canning Basin, Western Australia. These were used to generate a well-constrained stratigraphic framework and shelf-to-basin composite reconstruction of the carbonate system. The resultant integrated framework allows for unprecedented analysis of carbonate margin-to-slope heterogeneity, depositional architecture, and sequence stratigraphy along the Lennard Shelf. Systems tract architecture, facies partitioning, and stacking patterns of margin to lower-slope environments were assessed for six composite-scale sequences that form part of a transgressive-to-regressive supersequence and span the Frasnian-Famennian (F-F) biotic crisis. Variations are apparent in margin styles, foreslope facies proportions, dominant resedimentation processes, downslope contributing sediment factories, and vertical rock successions, related to hierarchical accommodation signals and ecological changes associated with the F-F boundary. We present these results in the form of carbonate margin-to-basin sequence stratigraphic models and associations that link seismicscale architecture to fine-scale facies heterogeneity. These models provide a predictive foundation for characterization of steep-sided flanks of reefal carbonate platform systems that is useful for both industry and academia. This study emphasizes the utility of an integrated stratigraphic approach and the insights gained from better-constrained facies and stratal architecture analysis, insights that were not achievable with traditional sequence stratigraphic or biostratigraphic techniques alone.

High-resolution, time-significant correlations are integral to meaningful stratigraphic frameworks in depositional systems, but may be difficult to achieve using traditional sequence stratigraphic or biostratigraphic approaches alone, particularly in geologically complex settings. In steep, reefal carbonate margin-to-slope systems, such correlations are essential to unravel shelf-to-basin transitions, characterize strike variability, and develop predictive sequence stratigraphic models – concepts which are currently poorly understood in these heterogeneous settings. The Canning Basin Chronostratigraphy Project (CBCP) integrates multiple independent datasets (including biostratigraphy, magnetostratigraphy, stable isotope chemostratigraphy, and sequence stratigraphy) extracted from Upper Devonian (Frasnian and Famennian) reefal platform exposures along the Lennard Shelf, Canning Basin, Western Australia. These were used to generate a well-constrained stratigraphic framework and shelf-...

During the late Miocene, reef complexes characterised by poorly diversified coral associations (mainly Porites, occasionally associated with Tarbellastraea and/or Siderastraea), became widespread in the Mediterranean area. One of these complexes crops out at Vigoleno (Castell'Arquato, Piacenza, Northern Italy). According to the regional palaeogeographic and palinspastic reconstructions, it can be considered up to now the northernmost late Miocene (Tortonian-Messinian) reef of the Mediterranean area. Despite the limited outcropping and the faulting, the multidisciplinary investigations reveal the anatomy of this reef complex along two reference sections. In addition, a marked cyclicity characterises both carbonate and siliciclastic deposits of the Vigoleno wedge-top basin. At present, the lack of reliable geochronological markers and unsuitability of the material for stable isotope analyses are not sufficient to constrain the time-span and the main controlling environmental factors of these depositional cycles.

During the late Miocene, reef complexes characterised by poorly diversified coral associations (mainly Porites, occasionally associated with Tarbellastraea and/or Siderastraea), became widespread in the Mediterranean area. One of these complexes crops out at Vigoleno (Castell'Arquato, Piacenza, Northern Italy). According to the regional palaeogeographic and palinspastic reconstructions, it can be considered up to now the northernmost late Miocene (Tortonian-Messinian) reef of the Mediterranean area. Despite the limited outcropping and the faulting, the multidisciplinary investigations reveal the anatomy of this reef complex along two reference sections. In addition, a marked cyclicity characterises both carbonate and siliciclastic deposits of the Vigoleno wedge-top basin. At present, the lack of reliable geochronological markers and unsuitability of the material for stable isotope analyses are not sufficient to constrain the time-span and the main controlling environmental factors of these depositional cycles.

The study of the Algarve margin on the basis of multichannel seismic profiles, tied with stratigraphic data from five exploration wells, illustrates the regional Cenozoic seismic stratigraphy and tectonics. Six seismic units (B to G), bounded by unconformities, form the Cenozoic cover that range in age from the early Paleocene to Quaternary. A stratigraphic correlation between the sedimentary record of the near Portuguese and Spanish areas is proposed, based on interpreted unconformities on seismic data considered to be related to main tectonic events that affected Iberia. This study provides a synthesis of the geodynamic evolution of the Gulf of Cadiz Portuguese margin in the context of the Africa-Eurasia plate boundary.

Once a field has been identified, and a general method of reservoir exploitation decided, there are several methods to achieve the reservoir management goal, but some ways may cost twice as much as others. The most critical operations to developing a field are drilling of wells, and it overemphasizes which in the early stages of field development. This study will cover challenges related to field development in the presence of a geological complication. In the Arabic Gulf area, most of the reservoirs are carbonate is distinguished by complex textural heterogeneity that corresponds to extreme permeability varieties which are the controlling factor in reservoir production. The uncertainty of information in the reservoir and rock mechanics properties have proven to be extremely challenging that faced oil and gas companies during the Appraisal and development phase. Numerous lost-time incidents including stuck pipe, packoff, lost circulation and difficulties in running casing were experienced during drilling new wells. Moreover, Due to the significant differences between log-derived water saturation and capillary pressure model-derived water saturation profiles during the dynamic model, the lake of the original hydrocarbon amount will raise the associated risks and uncertainties of the model. That becomes necessary to perform the task of integrated reservoir characterization and geomechanics in order to find optimum field development plan, that is the objective of this study was to characterized reservoir rock by distributing petrophysical rock types, porosity, and permeability and applied rock typing among the transition zone to increase the certainty of oil in place. Moreover, design a new modify for mud window to mitigate drilling hazard was one of the primary outcomes in this study. The objective of this study applied in a case study in the Arabic Gulf area. Several approaches were performed to determine which method was more reliable for our case study to identification rock typing, FZI*showed a better result than other methods, it has created three petrophysical rock types, which depend on specific porosity and permeability trends. The distribution of petrophysical rock type, porosity, and permeability perform in the form of the 3D model by using geostatic model. In the geomechanical evaluation, there was a notable difference in geomechanical characteristics. The values for these properties rise at deeper depths, most possibly because of the degree of the overburden and increased compaction, as shown in the increasing sonic speeds. A result from integrated rock typing and geomechanics showed that PRT 3 identified as a best reservoir and highest lost circulation zone, according to a highly porosity and permeability values that varies from 0.17 to 0.25 and from 237 to 349 MD respectively .Integrated FZI* as an indicator of loss circulation zone that showed probability of mud loss increased with increased FZI* values, with median line principle guide us to design a new approach for optimum mud window design to reduce L.C and tight hole problem. The outcomes of this research can be utilized in the field industry to improved reservoir characterized and mitigate drilling problem by applying our new modify for mud window design.

Two Permian-Triassic boundary sections (Lung Cam and Nhi Tao) in shallow marine carbonates from northern Vietnam, near the border between Vietnam and China, were studied for major and trace elemental variations as well as carbon and oxygen isotopic compositions. At the Nhi Tao section, we observe a continuous transition from Late Permian limestones, siliceous limestones and microbial limestones (Dong Dang Formation) to Early Triassic limestones and dolomitic limestones (Hong Ngai Formation). At the Lung Cam section, a thin layer of shale (the uppermost part of the Dong Dang Formation-Late Permian) separates carbonate layers of the Dong Dang Formation (Late Permian) from those of the Hong Ngai Formation (Early Triassic). There is a clear negative shift of about 2.5-3‰ in the δ 13 C values at both sections, beginning about 10 cm below the Permian-Triassic boundary as defined by paleontological and lithological data. The existence and extent of these excursions is compatible with introduction of 12 C-rich deep ocean water onto the shallow carbonate platform. In the Nhi Tao section, this negative shift in δ 13 C starts at about the same level as a change in magnetic susceptibility, indicating some input from terrestrial sources. The δ 13 C curves shows evidence for a rapid reduction in biomass, which may be related to the extinction event, and the long-term reduction in δ 13 C in the Early Triassic suggests long-term perturbation of the environment and slow recovery. The shift towards negative values indicates a reduction in carbon burial. The shape of the Ce/Ce* curve suggests that the redox conditions of depositional environments in both sections fluctuated, but that there was a decline in oxygenation with time, possibly into the anoxic range. Distinct negative anomalies coincide with the onset of the carbon isotope shifts, which might indicate additional influx of anoxic waters. The Th/U ratios in both sections are mainly less than 2, reinforcing this possibility. Upwelling of anoxic deep-ocean water onto the shallow carbonate platform at Nhi Tao and Lung Cam at the end of the Permian, with related disastrous consequences for the biosphere, is indicated by our data.

S eismic stratigraphy and seismic facies analysis provide a useful methodology for the genetic understanding of carbonate platform systems during exploration, initial assessment, and early field development (e.g. sparse well data). A high-resolution 2D seismic survey covering 7500 square kilometers allows documentation of the evolution of a Miocene-Pliocene carbonate platform in the East Natuna Sea, Indonesia. The Segitiga Platform (1400 sq. km.) contains Terumbu Formation carbonates up to 1800 meters thick that were deposited in platform interior, reef and shoal margin, and slope to basin environments of an isolated carbonate platform.

Houston Geological Society Bulletin 19 Seismic stratigraphy and seismic facies analysis provide a useful methodology for the genetic understanding of carbonate platform systems during exploration, initial assessment, and early field development (e.g. sparse well data). A high-resolution 2D seismic survey covering 7500 square kilometers allows documentation of the evolution of a MiocenePliocene carbonate platform in the East Natuna Sea, Indonesia. The Segitiga Platform (1400 sq. km.) contains Terumbu Formation carbonates up to 1800 meters thick that were deposited in platform interior, reef and shoal margin, and slope to basin environments of an isolated carbonate platform.