• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 118
  • 76
  • 40
  • 30
  • 13
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 1
  • 1
  • 1
  • Tagged with
  • 346
  • 94
  • 87
  • 48
  • 46
  • 41
  • 38
  • 37
  • 36
  • 35
  • 30
  • 29
  • 24
  • 24
  • 23
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
111

Paleoekologické aspekty evoluce ústřic rodu Rhynchostreon Bayle / Palaeoecological aspects of Rhynchostreon Bayle oyster evolution

Rantuch, Jakub January 2014 (has links)
This paper presents a multilevel analysis of palaeoecological aspects of the process of the Rhynchostreon genera evolution. According to the latest results of research, the process of genus appears to be more dynamic than previously assumed.The processes of internal dynamics of the environment in conjuncture with other studied aspects of the late cretaceous environment (e.g. paleotemperature, salinity, etc.) were a significant factor that initiated the activity of selective pressure and represents an important factor in group evolution. In this work we provide the overall hypothesis about co-evolution of two intrageneric (sisters) lineages in Rhynchostreon genera. The definiton of evolutionary trends of intrageneric lineages within the presented hypothesis (including a new description of oyster species) is supported by various analytical methods, which anchors them in the current zoological nomenclature system. An electron microscopy, isotopes and biometrical analysis of a shell in cooperation with some of the sedimentologic methods suggest a relation of lithology (as a result of environmental aspect) and evolution process. The transregional concept of proposed ecological-evolutionary models, based on materials studies from various paleogeographic regions of cretaceous world, increases the...
112

The ornithopod dinosaur Rhabdodon from the Late Cretaceous of France : anatomy, systematics and paleobiology / Le dinosaure ornithopode Rhabdodon dans le Crétacé supérieur de France : anatomie, systématique et paléobiologie

Chanthasit, Phornphen 30 June 2010 (has links)
Le dinosaure ornithopode Rhabdodon a été nommé par Matheron en 1869 et la première espèce,Rhabdodon priscus, a été proposée sur la base d'un fragment dentaire avec ses dents très caractéristiquesdécouvert dans le Crétacé supérieur des Bouches-du-Rhône dans le Sud de la France. Une nouvelle espèce, R.septimanicus., a ensuite été proposée par Buffetaut et Le Loeuff en 1991 sur la base d’un dentaire trouvé dansune localité du Crétacé supérieur à Montouliers (Hérault). La validité de cette nouvelle espèce était en débat, laquestion étant de savoir combien d'espèces de Rhabdodon existaient dans le Sud de la France. Un abondantmatériel inédit (crânien et postcrânien) de Rhabdodon, découvert récemment au cours de fouilles sur diverssites du Sud de la France, est décrit, de sorte que l’'anatomie de cet animal est désormais mieux connue. Unereconstitution de Rhabdodon est proposée. R. septimanicus est considéré comme valide à la suite de l'inclusionde nouveaux éléments crâniens de Quarante (Hérault). Deux espèces de Rhabdodon ont certainement coexistédurant le même période (Campanien supérieur – Maastrichtien inférieur) dans le Sud de la France. L'analysephylogénétique confirme que Rhabdodon peut être placé dans une famille des Rhabdodontidae avec son taxonfrère,Zalmoxes, dont il se distingue par de nombreux caractères postcrâniens. Les Rhabdodontidae sontproches des Iguanodontia. Il est suggéré que l'ancêtre commun des rhabdodontidés a évolué en Amérique duNord, puis s’est dispersé en Europe et a finalement évolué dans l'isolement géographique de l’archipeleuropéen au cours de du Crétacé supérieur. / The ornithopod dinosaur Rhabdodon was named by Matheron in 1869 and a first species,Rhabdodon priscus, was proposed on the basis of a dentary fragment with its diagnostic teeth from the LateCretaceous of Bouches-du-Rhône in southern France. A new species, R. septimanicus, was subsequentlyerected by Buffetaut and Le Loeuff (1991) based on a characteristic dentary from a Late Cretaceous locality atMontouliers (Hérault). The validity of the latter species was in debate, the question being how many species ofRhabdodon existed in Southern France. Abundant unpublished material (both cranial and postcranial) ofRhabdodon discovered in recent excavations at various localities in southern France is described, as a result ofwhich the anatomy of this animal is now better known. A reconstruction of Rhabdodon is proposed. R.septimanicus is considered as valid by including new cranial elements from Quarante (Hérault). Two species ofRhabdodon undoubtedly coexisted in the same time interval (Late Campanian – Early Maastrichtian) insouthern France. The phylogenetic analysis confirms that Rhabdodon can be placed in a distinct family,Rhabdodontidae, which also includes its sister taxon, Zalmoxes, from which it is distinguished by numerouspostcranial characters. Rhabdodontidae has a close relation with Iguanodontia. It is suggested that the commonancestor of the rhabdodontid dinosaurs evolved in North America, and then dispersed to Europe and eventuallyevolved in geographical isolation on the various European landmasses during the Late Cretaceous.
113

Hydrogeologie Skorkovského a Sojovického jímacího řadu na základě nových údajů z vrtů / Hydrogeology of Skorkov and Sojovice waterworks based on data from new water wells

Rybářová, Magdalena January 2015 (has links)
The Riverbank Filtration (RBF) water supply system Karany has been affected by increasing NO3- concentrations during recent decades. This thesis deals with flow and chemical composition of groundwater in Skorkov and Sojovice RBF systems, which are the most problematic ones according to their quality in long term. Twelve new groundwater wells (V1- V12) were drilled in study area in 2013. Data derived from the wells were used to improve the conceptual hdrogeological model of the area and I tried to specify information about the origin of nitrate pollution. The Groundwater level logging showed hydraulic connection between the river and the wells situated up to 130 m faraway from the river (V1, V2 andV10), which were also demonstrated by the short- term temperature fluctuations caused by fast penetration of surface water from The Jizera River during higher flow rate to wells. I compiled geological sections which show the geometry of The Quaternary fluvial deposits and groundwater level. The chemical analysis of groundwater showed that it is not possible to differentiate groundwater from the shallow part of The Cretaceous aquifer from the aquifer of fluvial deposits by major chemical components. The result of infiltration experiments showed higher permeability in the environment with grass cover (kv=...
114

Možnosti krasovění v přechodní facii České křídové pánve / Possibilities of Karstification in the Transitional Facies of the Bohemian Cretatious Basin

Balák, František January 2015 (has links)
In the region of Bohemian Cretaceous Basin can be found some springs with specific yield over 100 l/s. The doyen of Czech hydrogeology Prof. Hynie described some of those springs to be of karst origin and as the most permeable area he described the so-called transitional facies between shallow-water sandstones and deep-water marlstones. Possibilities of karstification have not yet been studied for rocks in the BCB, so the origin of well-permeable pathways in the BCB is a subject of speculations. This thesis deals with the question of which sedimentary rocks potentially allow the generation of karst permeability in the BCB. To do so, rock samples drilled from outcrops in the BCB were subjected to a fast dissolution simulation by leaching in hydrochloric acid. Carbonate content is measured by a standard and one's own method. Mineral composition, grain size and microscopic structure of rocks are studied with SEM. As is shown, the border of rock karstification is not defined just by the carbonate content, but also the grain size, rock structure and by the occurrence of fine secondary silicate content. Concerning the amount of dissolvable compounds, the border of total disintegration can be at 30 % of carbonate content for some rocks, but the most resistant rocks (mostly fine rocks with SiO2 matrix) stay intact...
115

Development of a Borehole Log Signature for Oceanic Anoxic Events and Its Application to the Gulf of Mexico

Brewton, Asani 19 December 2008 (has links)
Oceanic anoxic events (OAEs) are periods in Earth's history when oceans were depleted in dissolved oxygen and characterized by deposition of organic-rich sediments. The Oceanic Drilling Program (ODP) has drilled through OAEs in a number of areas worldwide, collecting core and borehole log data. This project attempts to identify a characteristic signature from known ODP OAE sections using these data and to apply the signature to identify OAE intervals in Gulf of Mexico wells where cores are lacking. Additionally, pseudo density curves were generated from ODP logs and compared to bulk density logs to determine if the deviation between the two would aid identification of OAE intervals. A general, though not fool proof, signature of high gamma ray, uranium, neutron porosity and low density was seen in nearly all of the ODP holes. Using this signature 20 potential OAE intervals were identified in the Gulf of Mexico.
116

Postcranial osteology and phylogenetic relationships of the Early Cretaceous titanosaur Tapuiasaurus macedoi Zaher et al. 2011 / Osteologia pós-craniana e relações filogenéticas do titanossauro do Cretáceo Inferior Tapuiasaurus macedoi Zaher et al. 2011

Navarro, Bruno Albert 03 May 2019 (has links)
Herein is presented a comprehensive description of the postcranial skeleton and phylogenetic analysis of the Early Cretaceous titanosaurian Tapuiasaurus macedoi Zaher et al. 2011. Tapuiasaurus becomes a key-taxon due its completeness, shedding new lights on the first steps in the early titanosaur evolution. The new information gathered by this study reveals that the presacral vertebrae anatomy of Tapuiasaurus possesses the typical apomorphic lithostrotian morphology (e.g. single neural spines, absence of hyposphene-hypantrum complex and aliform processes), whereas the architecture of fore and hindlimbs retains plesiomorphic characters, such as the presence of manual phalanges, as well as a pes with greater phalangeal count (=10). Contrasting with previous studies, the phylogenetic analysis retrieved Tapuiasaurus as an early lithostrotian, sister-taxon of the group formed by Yongjinglong datangi, from the Early Cretaceous of China, plus a relictual unnamed taxon from the Late Cretaceous of Minas Gerais State, the same region that in which Tapuiasaurus comes. The new recognized clade that would represents one of the first lithostrotian irradiations around the world, providing additional data that will help elucidate dispersion patterns in the group. This study reveals that the stepwise acquisition of the typical titanosaurian characters possesses a mosaic pattern, in which the apomorphic anatomy presented by the advanced titanosaurians was acquired along the last part of the Late Cretaceous, probably in the post Turonian time-interval (89.8 My) / É apresentada aqui uma abrangente descrição do esqueleto pós-craniano e análise filogenética do titanossauro do Cretáceo Inferior Tapuiasaurus macedoi Zaher et al. 2011. Tapuiasaurus representa um táxon-chave devido à sua alta completude, lançando novas luzes nos primeiros passos na evolução dos titanossauros. As novas informações coletadas por este estudo revelam que a anatomia das vértebras pré-sacrais de Tapuiasaurus possui uma típica morfologia litoestrotiana apomórfica (e.g. espinhos neurais não divididos, ausência do complexo hiposfeno-hipantro e de processos aliformes), enquanto que a arquitetura dos membros anteriores e posteriores retém caracteres plesiomórficos, como a presença de falanges manuais, bem como um pé com alta contagem falangeana (=10). Contrariando estudos anteriores, a análise filogenética realizada recuperou Tapuiasaurus como um litoestrotia basal, táxon-irmão do grupo formado por Yongjinglong datangi, do Cretáceo Inferior da China, mais um táxon relictual não nomeado do Cretáceo Superior do Estado de Minas Gerais, a mesma região geográfica na qual Tapuiasaurus provém. O novo clado reconhecido representaria uma das primeiras irradiações de litoestrotios em todo o mundo, fornecendo dados adicionais que ajudarão a elucidar os padrões de dispersão do grupo. Este estudo revela que a aquisição dos caracteres titanossaurianos típicos foi gradual, possuindo um padrão de mosaico, no qual a anatomia apomórfica apresentada pelos titanossauros avançados foi adquirida ao longo da última parte do Cretáceo Superior, provavelmente a partir do intervalo pós-Turoniano (89,8 M)
117

Descrição osteológica e posicionamento taxonômico de microvertebrados fósseis do Cretáceo Superior (Bacia Bauru) afloramento \"Tartaruguito\", município de Pirapozinho (SP) / Osteological description and taxonomic classification of the fossil microvertebrates from the upper Cretaceous (Bauru Basin) outcrop \"Tartaruguito\", city of Pirapozinho (SP)

Rosa, Melissa Padilha Duarte 06 December 2013 (has links)
No presente trabalho materiais de microvertebrados coletados no sítio fossilifero de Pirapozinho são descritos. Estão presentes nesta camada materiais fósseis de peixes, quelônios e dentes de dinossauro e crocodilo. Diversos estudos anteriores descreveram e posicionaram filogeneticamente o exemplar mais comum encontrado na localidade, o quelônio fóssil Bauruemys elegans, porém não existem trabalhos sistemáticos voltados para a descrição dos fragmentos presentes no afloramento. Para classificar taxonomicamente os materiais encontrados, foram empregados os materiais depositados em coleções científicas e a informação disponível na literatura. Grande parte do material triado corresponde a fragmentos que não puderam ser utilizados para descrição, pois apresentam considerável desgaste, provavelmente devido ao teor da camada que indica se tratarem de materiais oriundos de eventos de transporte hidráulico, hipótese levantada devido ao empacotamento, abrasão e completa dissociação e desarticulação que se encontram os materiais / In this work microvertebrate materials from Pirapozinho fossiliferous site were colected and described. In this strata are present fóssil material of fish, turtles and teeth of dinosaur and crocodile. Several previous works described and placed phylogenetically the most common specimenfound in this locality, the fóssil turtle Bauruemys elegans, however there are no systematic work focused on the fragments descriptions present in the locality. To classify taxonomically the materials found, were used the materials deposited in scientific collections and in information available in literature. Most of the material screened corresponds to fragments that could not be used for description, because they show considerable wear, probably due to the content of the strata that indicates that these material are related to events of hydraulic transport, hypothesis due to packaging, abrasion and complete dissociation and disarticulation ofthe materials
118

Redescrição da anatomia craniana e pós-craniana do fóssil Bauruemys elegans (Suárez, 1969) do Cretáceo Superior da Bacia Bauru e seu posicionamento filogenético dentro da Epifamília Podocnemidinura (Testudines, Pelomedusoides). / Redescription of cranial and post-cranial anatomy of Bauruemys elegans from Upper Cretaceous of Bauru Basin and its phylogenetical position within Epifamily Podocnemidinura (Pelurodira, Pelomedusoides)

Matiazzi, William 15 August 2007 (has links)
No presente trabalho o gênero fóssil Bauruemys elegans é redescrito. Sua anatomia craniana e pós-craniana foi analisada em detalhes com base em novos exemplares coletados deste fóssil. Bauruemys elegans é um quelônio do Cretáceo Superior da Bacia Bauru, encontrado no Município de Pirapozinho, interior do estado de São Paulo e descrito originalmente por Suárez em 1969 como “Podocnemis elegans". Os materiais analisados foram comparados com a osteologia de representantes atuais dos clados Chelidae, Pelomedusidae e Podocnemididae, bem como com descrições de outros táxons disponíveis na literatura. As relações filogenéticas de Bauruemys elegans dentro do clado Podocnemidinura foram analisadas através da análise de parcimônia envolvendo 19 táxons e 56 caracteres. Nesta análise Bauruemys elegans constitui, de fato, um gênero distinto entre os podocnemidídeos, corroborando propostas já descritas na literatura. A análise também revelou que, através dos caracteres osteológicos, Bauruemys elegans possui afinidades filogenéticas próximas aos podocnemidídeos atuais, posicionando-se como grupo-irmão do clado formado pelo fóssil Cambaremys langertoni e pela Família Podocnemididae. / In this study, the fossil Bauruemys elegans is redescribed. Its cranial and postcranial anatomy was analysed in detail based on new specimens collected. Bauruemys elegans is a chelonian from Upper Cretaceous of the Bauru Basin founded in the municipality of Pirapozinho, São Paulo state and was originally described by Suarez (1969) as Podocnemis elegans. The specimens analysed was compared with some extant representatives of Chelidae, Pelomedusidae and Podocnemididae families and descriptions avaliable on the literature. The phylogenetic affinities of the Bauruemys elegans within Podocnemidinura was evaluated through a parsimony analysis envolving 19 taxa and 56 characters. The results of phylogenetic analysis shows that Bauruemys elegans is, in fact, a distinct genus within the clade Podocnemididae. This corroborated anterior hypothesis proposed. Adittionally, this analysis using osteological characters, indicate Bauruemys elegans as the sister group of Cambaremys langertoni and Podocnemididae.
119

Descrição morfológica e posicionamento filogenético de um Baurusuchidae (Crocodyliformes, Mesoeucrocodylia) do Cretáceo Superior da Bacia Bauru, região de General Salgado (SP). / Morphological description and phylogenetical position of a Baurusuchidae (Crocodyliformes, Mesoeucrocodylia) from Late Cretaceous of Bauru Basin, General Salgado area (São Paulo state)

Nascimento, Paulo Miranda 02 July 2008 (has links)
A região de General Salgado (Formação Adamantina, Bacia Bauru) mostra-se como uma região extremamente rica em fósseis de vertebrados. Essa riqueza evidencia-se na presença de diversos registros de Crocodilianos do Cretáceo. Entre eles, encontra-se um esqueleto articulado, composto por partes do crânio e um pó-crânio praticamente completo. Os caracteres que alocam o exemplar à família Baurusuchidae são: o quadrado altamente verticalizado, com a presença de uma concavidade na sua superfície lateral, a conformação da mandíbula, a presença de uma depressão longitudinal na porção anterior do jugal e a expansão descendente da aba lateral do esquamosal. A presente descrição de pós-crânio é a primeira realizada para um táxon da família extinta Baurusuchidae. Já foi noticiada a existência de material pós-craniano deste clado extinto de Crocodyliformes, porém nenhum exemplar foi realmente descrito até o presente momento. Esse material fóssil parece pertencer a novo táxon, devido à sua conformação peculiar do jugal, do processo retro-articular e da expansão descendente da aba lateral do esquamosal. Os caracteres levantados foram empregados para definir a posição filogenética e taxonômica do exemplar no grupo dos Notosuchia, e pretende-se, com isso, contribuir para a compreensão da diversidade dos mesmos. / The area of General Salgado (Adamantina Formation, Bauru Basin) is extremely rich in vertebrate fossils. This richeness is evident with the presence of several records of Cretaceous crocodiliforms. Among them, an articulated skeleton of a new Baurusuchidae was found, composed by parts of the cranium and a practically complete post-cranium. Characters that place the specimen in the family Baurusuchidae are: the highly verticalized quadrate, with the presence of a cavity in its lateral surface; the configuration of the jaw; the presence of a longitudinal depression in the first portion of the jugal; and the descendent expansion of the lateral edge of the esquamosal. The present postcranial description is the first one provided for taxon of the extinct family Baurusuchidae. This fossil material appears to belong to a new taxon, due to the peculiar configuration of its jugal, of the retro-articular process, and of the descendent expansion of the lateral edge of the esquamosal. The gathered caracters were used to define the filogenetic and taxonomic position of the specimen in Notosuchia. With this filogenetic analysis, it is expected to contribute with the comprehension of the diversity of the group.
120

Ostracodes do cretáceo-paleógeno inferior da Bacia de Pelotas

Ceolin, Daiane January 2010 (has links)
Submitted by Vanessa Nunes (vnunes@unisinos.br) on 2015-03-21T13:53:52Z No. of bitstreams: 1 DaianeCeolin.pdf: 3969335 bytes, checksum: 5d7bd449fc1307161fd904deef944280 (MD5) / Made available in DSpace on 2015-03-21T13:53:52Z (GMT). No. of bitstreams: 1 DaianeCeolin.pdf: 3969335 bytes, checksum: 5d7bd449fc1307161fd904deef944280 (MD5) Previous issue date: 2010 / CNPQ – Conselho Nacional de Desenvolvimento Científico e Tecnológico / O presente trabalho consiste no estudo taxonômico dos ostracodes marinhos da bacia de Pelotas e os respectivos aspectos paleoecológicos da assembléia no intervalo Cretáceo e Cretáceo – Paleógeno Inferior. Foram analisadas 479 amostras de calha, provenientes dos cinco poços 1-RSS-2, 1-RSS-3, 2-RSS-1, 1-SCS-3B e 1-SCS-2. A fauna registrada totalizou 98 espécimes, distribuídos em nove famílias, 21 gêneros, 34 espécies. Dois gêneros e duas espécies foram mantidos como táxons indeterminados. As espécies identificadas foram: Cytherella cf. C. araucana Bertels, 1974; Cytherelloidea spirocostata Bertels, 1973; Bairdoppilata triangulata Edwards, 1944; Actinocythereis indígena Bertels, 1969; Brachycythere gr. sapucariensis Krömmelbein, 1964; Wichmannella araucana Bertels, 1969 e Wichmannella meridionalis Bertels, 1969. Os gêneros mais diversificados foram Cytherella e Paracypris com sete e quatro espécies, respectivamente. O intervalo Turoniano foi o mais abundante, com a significativa presença dos gêneros Brachycythere e Cytherella . A família mais abundante foi a Trachyleberididae, com oito gêneros e 12 espécies, seguida da família Cytherellidae com dois gêneros e oito espécies. A passagem do limite Cretáceo – Paleógeno Inferior (K– Pg) na bacia de Pelotas foi marcada por uma mudança faunística com o desaparecimento dos gêneros, therelloidea, Argilloecia, Cythereis, Brachycythere, Pondoina e Rostrocytheridea, e o aparecimento de Neonesidea, Bairdoppilata, Ambocythere, Buntonia, Langiella?, Trachyleberis e Krithe . A associação dos ostracodes cretácicos na bacia de Pelotas sugere um ambiente marinho nerítico com águas quentes. / The taxonomic study of marine ostracods from Pelotas Basin and the respectives paleoecological assemblages aspects in the Cretaceous and Cretaceous – Lower Paleogene interval were studied. 479 cutting samples from wells 1-RSS-2, 1-RSS-3, 2-RSS-1, 1-SCS-3B e 1-SCS-2 were analized. 98 specimes belonging to 9 families, 21 genera and 34 species. 2 genera and 2 species were supported as undetermined taxon. The species identified were: Cytherella cf. C. araucana Bertels, 1974; Cytherelloidea spirocostata Bertels, 1973; Bairdoppilata triangulata Edwards, 1944; Actinocythereis indígena Bertels, 1969; Brachycythere gr. sapucariensis Krömmelbein, 1964; ichmannella araucana Bertels, 1969 and Wichmannella meridionalis Bertels, 1969. The most diversified genera were Cytherella and Paracypris with 7 and 4 species, respectively. The Turonian was the most ostracodes-rich interval with significant presence of the genera Brachycythere and Cytherella. The most abundant families were Trachyleberididae and Cyther ellidae with 2 genera and 8 species. The K – Pg boundary in the Pelotas basin is marked by a faunal change which disappearance the genera Cytherelloidea, Argilloecia, Cythereis, Brachycythere, Pondoina and Rostrocytheridea, and the first occurrence of Neonesidea, Bairdoppilata, Ambocythere Buntonia, Langiella?, Trachyleberis and Krithe. The Cretaceous ostracods association in Pelotas Basin sugest a neritic marin e environment with warm water temperatures.

Page generated in 0.0466 seconds