No description available.

No description available.

In central Anatolia, Turkey, a strand of the former northern Neotethys Ocean subducted northwards under the Eurasian (Pontide) active margin during Late Cretaceous–Early Cenozoic time. Subduction and regional plate convergence were associated with the generation and emplacement of accretionary complexes and supra-subduction zone-type ophiolites onto former passive margins of microcontinents. The resultant suture zones contain Late Cretaceous to Middle Eocene basins (“The Central Anatolian Basins”) including: 1) the Kırıkkale Basin; 2) the Çankırı Basin, 3) the Tuz Gölü Basin and; 4) the Haymana - Polatlı Basin. Using stratigraphic logging, igneous geochemistry, micropalaeontology and provenance studies, this study tests two end-member models of basin evolution. In model one, the basins developed on obducted ophiolitic nappes following closure of a single northern Neotethys Ocean during the latest Cretaceous. In model two, northern Neotethys comprised two oceanic strands, the İzmir-Ankara-Erzincan Ocean to the north and the Inner Tauride Ocean to the south, separated by the Niğde-Kırşehir microcontinent, which was rifted from the Gondwana continent to the south. In this scenario, the basins developed as accretionary-type basins, associated with north-dipping subduction which persisted until the Middle Eocene when continental collision occurred. Where exposed, the basements of the Central Anatolian Basins comprise the Ankara Mélange, a mainly Upper Cretaceous subduction-accretion complex and the western/northern margin of the Niğde-Kırşehir microcontinent. New geochemical data from the composite basement of the Kırıkkale Basin identify mid ocean-ridge basalt (MORB), here interpreted to represent relict Upper Cretaceous Neotethyan oceanic crust. During the latest Cretaceous, the Kırıkkale and Tuz Gölü Basins initiated in deep water above relict MORB crust and ophiolitic mélange, bordered by the Niğde-Kırşehir microcontinent to the east where marginal facies accumulated. Further west, the Haymana-Polatlı Basin represents an accretionary-type basin constructed on the Ankara Mélange. To the north, the Çankırı Basin developed on accretionary mélange, bounded by the Pontide active margin to the north. Palaeocene sedimentation was dominated by marginal coralgal reef facies and siliciclastic turbidites. Latest Palaeocene–middle Eocene facies include shelf-type Nummulitid limestone, shallow-marine deltaic pebbly sandstones and siliciclastic turbidites. This thesis proposes a new model in which two north-dipping subduction zones were active during the late Mesozoic within northern Neotethys. In the south, ophiolites formed above a subduction zone consuming the Inner Tauride Ocean until the southward retreating trench collided with the northern margin of the Tauride continent emplacing ophiolites and mélange. In the north, subduction initiated outboard of the Eurasian margin triggering the genesis of supra-subduction zone ophiolites; the subduction zone rolled back southwards until it collided with the Niğde-Kırşehir microcontinent, again emplacing ophiolites during latest Cretaceous time. Neotethyan MORB still remained to the west of the Niğde-Kırşehir microcontinent forming the basement of the Kırıkkale and Tuz Gölü Basins. Latest Palaeocene–middle Eocene regional convergence culminated in crustal thickening, folding, uplift and strike-slip faulting which represent final continental collision and the geotectonic assembly of central Anatolia.

Mariliasuchus amarali Carvalho & Bertini 1999 é um crocodilomorfo Notosuchia do Cretáceo da Bacia Bauru. Este táxon possui um registro fóssil relativamente comum, e diversos espécimes (incluindo animais juvenis) são conhecidos. Portanto, ele representa um dos poucos táxons fósseis que permitem uma análise ontogenética, e seu desenvolvimento foi comparado com o do gênero Caiman (incluindo C. latirostris, C. crocodilus e C. yacare), um crocodilomorfo atual de ampla distribuição pela América do Sul. Foram empregadas as seguintes metodologias para comparação das trajetórias ontogenéticas dos táxons fóssil e atual: descrição qualitativa, morfometria linear e morfometria geométrica. Os dados obtidos destacaram trajetórias ontogenéticas comuns aos dois táxons, que foram interpretadas como o resultado de um padrão plesiomórfico aos Crocodyliformes, e distintas trajetórias ontogenéticas que foram relacionadas, principalmente, a diferentes adaptações ecomorfológicas. A ocorrência de tendências ontogenéticas como a manutenção de uma fenestra supratemporal de grandes proporções ao longo da ontogenia, a expansão anterior do articular e do côndilo mandibular do quadrado, o aumento na espessura da camada de esmalte dentário e a alometria positiva das fenestras infratemporal e mandibular sugerem que Mariliasuchus amarali aumentava gradativamente seu controle e capacidade de processamento alimentar ao longo de seu desenvolvimento. A análise ontogenética também mostrou fortes evidências de que o espécime UFRJ-DG 56-R, interpretado por Nobre et al. (2007a) como uma nova espécie dentro do gênero Mariliasuchus (M. robustus), é na verdade um indivíduo de M. amarali em avançado estágio de desenvolvimento e não uma nova espécie. O espécime MZSP-PV 760 é descrito pela primeira vez no presente trabalho. Suas características anatômicas sugerem que o mesmo não é um indivíduo juvenil de Mariliasuchus, como pensado anteriormente, mas parece estar relacionado ao clado que inclui ambos M. amarali e Adamantinasuchus navae (outro crocodilomorfo da Bacia Bauru). MZSP-PV 760 representa o mais jovem crocodilomorfo pós-embrionário já descrito para o Cretáceo de Gondwana. Uma reanálise da dentição altamente heterodonte em M. amarali mostrou a ocorrência de um novo morfótipo dentário (pré-molariforme), descrito pela primeira vez no presente trabalho. Uma coroa de cada morfótipo dentário foi extraída do espécime MZSP-PV 813 para análise da microanatomia do esmalte dentário e do padrão de organização dos cristais de esmalte, descritos pela primeira vez para um Notosuchia. A descrição de um novo morfótipo dentário representa uma inesperada adição para uma já complexa condição heterodonte em M. amarali, corroborando com a hipótese de OConnor et al. (2010) de que os Notosuchia podem ter ocupado nichos ecológicos e ecomorfoespaços, durante o Cretáceo do Gondwana, tão complexos quanto os de mamíferos. / Mariliasuchus amarali Carvalho & Bertini 1999 is a notosuchian crocodyliform from the Cretaceous of Bauru Basin (Brazil). This taxon has a fossil record that is relatively common, and several specimens (including juveniles) are known. Therefore, it represents one of the few fossil taxa that allows an ontogenetic approach, and its development was compared with the genus Caiman (including C. latirostris, C. crocodilus and C. yacare), a widespread South American crocodyliform. I used the following methodologies for the comparison of the ontogenetic trajectories of the fossil and living taxa: qualitative description, traditional morphometrics and geometric morphometrics. The data highlighted common ontogenetic trajectories that were interpreted as the result of a plesiomorphic pattern for Crocodyliformes, and distinct ontogenetic trajectories that were related mainly to different ecomorphological adaptations. The occurrence of ontogenetic trends as the retention of a large supratemporal fenestra along the ontogenetic development, the anterior expansion of the articular and the articular condyle of the quadrate, the thickening of the enamel cap in the teeth crowns, and the positive allometry of both infratemporal and mandibular fenestrae, suggest that Mariliasuchus amarali gradually increased its control and capacity of food processing along its ontogeny. The ontogenetic analysis also provided compeling evidence that specimen UFRJ-DG 56-R, interpreted by Nobre et al. (2007a) as a new species of the genus Mariliasuchus (M. robustus), is actually an individual of M. amarali in an advanced stage of development rather than a new species. Specimen MZSP-PV 760 is described for the first time here. Its anatomical characteristics suggest that this individual is not a juvenile specimen of Mariliasuchus amarali, as previously thought, but rather appears to be related to the clade that includes both M. amarali and Adamantinasuchus navae (another Bauru Basin crocodyliform). MZSP-PV 760 represents the youngest post-hatchling crocodyliform described for the Cretaceous of Gondwana. A reevaluation of the highly heterodont dentition of M. amarali showed the occurrence of a new tooth morphotype (premolariform), described here for the first time. A crown from each tooth morphotype was extracted from the specimen MZSP-PV 813 to perform an analysis of the enamel microanatomy and organizational patterns of enamel crystallities, described for the first time within Notosuchia. The description of a new tooth morphotype represents an unexpected addition to an already complex heterodont condition in M. amarali, adding to OConnor et al.s (2010) hypothesis that Notosuchia could have filled complex niches and ecomorphospaces during the Cretaceous of Gondwana similar to the ones occupied by mammals.

Mariliasuchus amarali Carvalho & Bertini 1999 é um crocodilomorfo Notosuchia do Cretáceo da Bacia Bauru. Este táxon possui um registro fóssil relativamente comum, e diversos espécimes (incluindo animais juvenis) são conhecidos. Portanto, ele representa um dos poucos táxons fósseis que permitem uma análise ontogenética, e seu desenvolvimento foi comparado com o do gênero Caiman (incluindo C. latirostris, C. crocodilus e C. yacare), um crocodilomorfo atual de ampla distribuição pela América do Sul. Foram empregadas as seguintes metodologias para comparação das trajetórias ontogenéticas dos táxons fóssil e atual: descrição qualitativa, morfometria linear e morfometria geométrica. Os dados obtidos destacaram trajetórias ontogenéticas comuns aos dois táxons, que foram interpretadas como o resultado de um padrão plesiomórfico aos Crocodyliformes, e distintas trajetórias ontogenéticas que foram relacionadas, principalmente, a diferentes adaptações ecomorfológicas. A ocorrência de tendências ontogenéticas como a manutenção de uma fenestra supratemporal de grandes proporções ao longo da ontogenia, a expansão anterior do articular e do côndilo mandibular do quadrado, o aumento na espessura da camada de esmalte dentário e a alometria positiva das fenestras infratemporal e mandibular sugerem que Mariliasuchus amarali aumentava gradativamente seu controle e capacidade de processamento alimentar ao longo de seu desenvolvimento. A análise ontogenética também mostrou fortes evidências de que o espécime UFRJ-DG 56-R, interpretado por Nobre et al. (2007a) como uma nova espécie dentro do gênero Mariliasuchus (M. robustus), é na verdade um indivíduo de M. amarali em avançado estágio de desenvolvimento e não uma nova espécie. O espécime MZSP-PV 760 é descrito pela primeira vez no presente trabalho. Suas características anatômicas sugerem que o mesmo não é um indivíduo juvenil de Mariliasuchus, como pensado anteriormente, mas parece estar relacionado ao clado que inclui ambos M. amarali e Adamantinasuchus navae (outro crocodilomorfo da Bacia Bauru). MZSP-PV 760 representa o mais jovem crocodilomorfo pós-embrionário já descrito para o Cretáceo de Gondwana. Uma reanálise da dentição altamente heterodonte em M. amarali mostrou a ocorrência de um novo morfótipo dentário (pré-molariforme), descrito pela primeira vez no presente trabalho. Uma coroa de cada morfótipo dentário foi extraída do espécime MZSP-PV 813 para análise da microanatomia do esmalte dentário e do padrão de organização dos cristais de esmalte, descritos pela primeira vez para um Notosuchia. A descrição de um novo morfótipo dentário representa uma inesperada adição para uma já complexa condição heterodonte em M. amarali, corroborando com a hipótese de OConnor et al. (2010) de que os Notosuchia podem ter ocupado nichos ecológicos e ecomorfoespaços, durante o Cretáceo do Gondwana, tão complexos quanto os de mamíferos. / Mariliasuchus amarali Carvalho & Bertini 1999 is a notosuchian crocodyliform from the Cretaceous of Bauru Basin (Brazil). This taxon has a fossil record that is relatively common, and several specimens (including juveniles) are known. Therefore, it represents one of the few fossil taxa that allows an ontogenetic approach, and its development was compared with the genus Caiman (including C. latirostris, C. crocodilus and C. yacare), a widespread South American crocodyliform. I used the following methodologies for the comparison of the ontogenetic trajectories of the fossil and living taxa: qualitative description, traditional morphometrics and geometric morphometrics. The data highlighted common ontogenetic trajectories that were interpreted as the result of a plesiomorphic pattern for Crocodyliformes, and distinct ontogenetic trajectories that were related mainly to different ecomorphological adaptations. The occurrence of ontogenetic trends as the retention of a large supratemporal fenestra along the ontogenetic development, the anterior expansion of the articular and the articular condyle of the quadrate, the thickening of the enamel cap in the teeth crowns, and the positive allometry of both infratemporal and mandibular fenestrae, suggest that Mariliasuchus amarali gradually increased its control and capacity of food processing along its ontogeny. The ontogenetic analysis also provided compeling evidence that specimen UFRJ-DG 56-R, interpreted by Nobre et al. (2007a) as a new species of the genus Mariliasuchus (M. robustus), is actually an individual of M. amarali in an advanced stage of development rather than a new species. Specimen MZSP-PV 760 is described for the first time here. Its anatomical characteristics suggest that this individual is not a juvenile specimen of Mariliasuchus amarali, as previously thought, but rather appears to be related to the clade that includes both M. amarali and Adamantinasuchus navae (another Bauru Basin crocodyliform). MZSP-PV 760 represents the youngest post-hatchling crocodyliform described for the Cretaceous of Gondwana. A reevaluation of the highly heterodont dentition of M. amarali showed the occurrence of a new tooth morphotype (premolariform), described here for the first time. A crown from each tooth morphotype was extracted from the specimen MZSP-PV 813 to perform an analysis of the enamel microanatomy and organizational patterns of enamel crystallities, described for the first time within Notosuchia. The description of a new tooth morphotype represents an unexpected addition to an already complex heterodont condition in M. amarali, adding to OConnor et al.s (2010) hypothesis that Notosuchia could have filled complex niches and ecomorphospaces during the Cretaceous of Gondwana similar to the ones occupied by mammals.

No description available.

The presented thesis is focused on the Radiolaria of the Czech Cretaceous Basin. The studied material was collected in Březno u Loun and in the Úpohlavy quarry. Biology, ecology and morphology, as well as systematics of the whole group is discussed. An important part of this thesis constitutes of the geological settings of Cretaceous, Czech Cretaceous Basin and both localities. 26 samples from Březno and 24 samples from the Úpohlavy quarry have been studied using several methods with the aim to obtain most numerous and best preserved communities possible. Despite poor preservation of the shells, 9 species have been identified. Several shells have been assigned at least to the genus or order levels. Species of Dictyomitra communis (Squinabol, 1904), Dictyomitra cf. napaensis Pessagno, 1976, Turbocapsula cf. giennensis O'Dogherty, 1994, Novixitus cf. mclaughlini Pessagno, 1977, Stichomitra cf. stocki (Campbell & Clark, 1944), Stichomitra communis Squinabol, 1903, Stichomitra japonica (Nakaseko & Nishimura), in Nakaseko et. al., 1979, Holocryptocanium barbui Dumitrica, 1970, cf. Pseudoaulophacus pargueraensis Pessagno, 1963 and genera of Orbiculiforma, Stichomitra, cf. Cryptamphorella have been reported in the Czech Cretaceous Basin for the first time.

Carbonate rocks consider as significant reservoirs for hydrocarbon. More than 60% of the world's hydrocarbon is placed in carbonate reservoirs. Carbonate rocks are heterogeneous and contain complex pore system. This complexity causes the hydrocarbon recovery from these reservoirs difficult; having less than 35% of hydrocarbon is being recovered. The heterogeneity and the variation in pore system are a result of various depositional settings and successive diagenetic overprints. Diagenetic overprints account for most of the pore system complexity in subsurface. This project undertakes one of the important diagenetic processes, calcite cementation, which though to have major impact on reservoir quality. The project aims to better understand the controls on calcite cementation in five Lower Cretaceous Reservoirs, in particular the role of calcite cementation with relation to oil charge in reservoir quality. Other diagenetic processes were also asses including dolomitization, dissolution, micritization and chemical compaction. The five reservoirs (A, B, C, F & G) are from Field A which is located in Abu Dhabi, UAE. The reservoirs comprise of interbedded porous "Reservoir" and low porosity-permeability "Dense" limestones deposited in broad range of settings, ranging from restricted to open marine platform. Reservoir intervals are part of HSTs, deposited during higher sea level time. The dense intervals were deposited during TST and thought to be cemented early resulting in early compartmentalization in all reservoirs. The mMg/Ca and in-situ (SIMS) δ18OVPDB were measured through complete calcite cement stratigraphy obtained from equant, syntaxial and blocky calcite in all reservoirs. Both mMg/Ca and δ18OVPDB of oldest calcite cement zone are matching with published mMg/Ca and δ18OVPDB of Lower Cretaceous, suggesting precipitation from Lower Cretaceous seawater. The mMg/Ca and δ18OVPDB also vary from reservoir to another reflecting change in Cretaceous seawater. These data also coincide with trace element observations particularly Mn and Sr. All these parameters show fluctuations in Cretaceous seawater during 135-123Ma caused by global changes in climate and oceanic crust production rates. Lower reservoirs including F (133Ma) and C (130Ma) were more probably affected by the Hauterivian global cooling which resulted in higher δ18OVPDB in the early precipitated cements. Precipitation in upper Reservoir B (126Ma) was most likely affected by the abrupt warm episode just before the OAE1. Reservoir A (123Ma) precipitation may be affected by the Early Aptian cooling episode and the OAE1. Reservoir G is the only one not recording δ18OVPDB similar of Cretaceous seawater. Cementation in Reservoir G was affected by depleted δ18OVPDB fluids from early stage, perhaps hot, basinal waters. More interestingly, the mMg/Ca, δ18OVPDB Mn and Sr means of younger calcite cement zones which thought to be evolved during burial show similar trend to the oldest cement zones with various offsets. This suggests that calcite cement in each reservoir evolved in a relatively close system inferring by this that the reservoirs are compartmentalized. The compartmentalization is probably due to the sysedimentary or early cemented hardgrounds in the Dense Zones. The Dense Zones acted as seals for the reservoirs from early stage causing the later precipitated calcite cement which is diagenetically affected to behave in predictable and similar way. Moreover, calcite precipitation temperatures inferred from mMg/Ca and δ18OVPDB show progressive increase towards younger cement zones indicating fluid evolution with burial in also relatively close system. In-situ δ18OVPDB and oil inclusions suggest earlier oil charge in the shallower reservoirs compared with deeper reservoirs and coeval water leg. Consequently, cementation in the shallower reservoirs continued with lower rate and hence preserved some primary and secondary pores. Conversely, in the water leg cementation continue to occlude most of the pore spaces. Furthermore, early oil emplacement in the shallower reservoirs increased the cementation temperature of calcite in the oil leg to reach maximum precipitation temperatures of ~144˚C. Whereas, in the water leg and deeper reservoirs, cementation continued to a temperature of ~110˚C. Overall, reservoir quality in Thamama Group was affected by various diagenetic processes. Some have resulted in reservoir quality enhancement such as dolimitization which involves formation of microporosity as a result of replacive rhombic dolomite, dissolution particularly the late one which believed to be due organic acid, and micritization with yield microporosity particularly in Reservoir B. Open fractures might have also enhanced reservoir quality to some extent. Diagenetic events that have deteriorated reservoir quality include calcite and saddle dolomite cementation as well as stylolitization. Greater calcite cementation can be found in water leg compared with oil leg because oil thought to decrease cementation rate.

Philosophiae Doctor - PhD / Integrated approaches in the study of petroleum exploration are increasingly becoming significant in recent times and have yielded much better result as oil exploration is a combination of different related topics. The production capacity in hydrocarbon exploration has been the major concern for oil and gas industries. In the present work an integrated approach was made with seismic, well logs and biostratigraphy for predicting the depositional environment and to understand the heterogeneity within the reservoirs belonging to Valanginian (Early Cretaceous) age of Gamtoos Basin, Offshore South Africa. Objectively, the integrated work was mainly based on seismic stratigraphy (seismic sequence and seismic facie analysis) for interpretation of the depositional environments with combination of microfossil biostratigraphic inputs. The biostratigraphic study provides evidences of paleo depth from benthic foraminifera and information about bottom condition within the sedimentary basin, changing of depositional depth during gradual basinal fill during the Valanginian time. The petrophysical characterization of the reservoir succession was based on formation evaluation studies using well logs to investigate the hydrocarbon potential of the reservoir across Valanginian depositional sequence. Further, the static modeling from 2D-seismic data interpreted to a geological map to 3D-numerical modeling by stochastic model to quantify the evaluation of uncertainty for accurate characterisation of the reservoir sandstones and to provide better understanding of the spatial distribution of the discrete and continuous Petrophysical properties within the study area.

Lower Cretaceous basins associated with the Hohhot detachment in the Daqing Shan of Inner Mongolia, China, allow us to better understand the tectonic evolution of extensional basins formed in association with detachment faulting and metamorphic core complex formation. The six basins, informally named N1, N2, S1, S2, S3, and S4, are located in different structural settings, or depozones, throughout the detachment-metamorphic core complex setting, and although all basins are consistent with previously proposed models for supradetachment basin sedimentation, second-order variability in sedimentary style is exerted by these distinct structural settings. The basins are composed of coarse, predominantly footwall derived, conglomerate deposited by masswasting and alluvial fan processes. Paleocurrent direction is generally southerly, indicating transverse transport away from the bounding detachment fault. Two of the basins, N2 and S3, provide us with an understanding of the temporal evolution of supradetachment basins in the upper plate of a metamorphic core complex. These basins were joined in their early stages, but were later separated as extensional unroofing exhumed the lower plate of the core complex and folded the master detachment fault, causing it to propagate a new splay to the surface. Continued extension was accommodated on this new splay, allowing for continued deposition of Lower Cretaceous strata above the detachment fault on the southern flank of the Daqing Shan antiform. Another basin, S2, displays the same stratigraphy and records a similar evolution, but we speculate that it formed separately in a primary corrugation of the master detachment fault. The only unit exposed in basin S4, located near the eastern end of the detachment, is the uppermost unit. Paleocurrent and provenance data are similar to other basins. Thus, it strongly resembles the other basins in spite of the magnitude of extension. Basin S1 is located in an intra-hanging wall setting and resembles the other basins with the exception of a centrally located fine-grained interval. Basin N1 was filled by similar depositional processes, but the proportions of fill that these processes are responsible for is variable in comparison to the other Lower Cretaceous basins in the Daqing Shan. This study establishes that the basins described are all of similar geometry and depositional style, and that supradetachment basins of this style may occur in various positions within a detachment-metamorphic core complex setting, regardless of proximity to the exhumed metamorphic core and magnitude of extension.