Thesis (Ph. D.)--Rice University, 1974. / Includes bibliographical references (leaves 112-125).

Submitted by Izabel Franco (izabel-franco@ufscar.br) on 2016-10-04T19:08:31Z No. of bitstreams: 1 DissRMAS.pdf: 2567370 bytes, checksum: 878fab5581b7d1cab72a62b808602d5a (MD5) / Approved for entry into archive by Marina Freitas (marinapf@ufscar.br) on 2016-10-20T18:17:46Z (GMT) No. of bitstreams: 1 DissRMAS.pdf: 2567370 bytes, checksum: 878fab5581b7d1cab72a62b808602d5a (MD5) / Approved for entry into archive by Marina Freitas (marinapf@ufscar.br) on 2016-10-20T18:17:53Z (GMT) No. of bitstreams: 1 DissRMAS.pdf: 2567370 bytes, checksum: 878fab5581b7d1cab72a62b808602d5a (MD5) / Made available in DSpace on 2016-10-20T18:18:00Z (GMT). No. of bitstreams: 1 DissRMAS.pdf: 2567370 bytes, checksum: 878fab5581b7d1cab72a62b808602d5a (MD5) Previous issue date: 2016-05-12 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Ichnofossils are abundant in the sandstones of the Botucatu Formation, Paraná Basin, of Neocomian age. This formation covers much of the Midwest, Southeast and South of Brazil, and other countries in South America. Several sandstone samples containing trace fossils were collected and deposited in the paleontological collection of the Departmento de Ecologia e Biologia Evolutiva (DEBE) of the Universidade Federal de São Carlos (UFSCar). In this work, trace fossils attributed to arachnids, i.e. ichnogenera Paleohelcura Gilmore, 1926 and Octopodichnus Gilmore, 1927, were studied and their presence is recorded for the first time in Brazil. The aim of this study was to infer how different environmental conditions such as moisture, texture, substrate inclination and even behavioral aspects of the organisms can affect the structure of the traces left by different arthropods. To do this, several neoichnological experiments were made, with six arachnids (two Tityus serrulatus, one Lycosa sp., one Loxosceles sp., and two individuals of the family Gonyleptidae) and five individuals of other invertebrate classes (three insects, one isopod and one diplopod). The experiments consisted on making the animals walk on a tray with sand of different grain sizes, different inclinations and different moisture levels. The results of these experiments, which showed different trace morphologies, according to each imposed condition, proved the influence of these conditions on the morphology of the footprints and on the behavior of the studied animals. In addition, these results showed how, in some situations, for example, in an uphill movement in a slope of 30° of inclination, it’s possible that animals with highly different track’s shapes leave very similar tracks, thus making much more difficult the identification of the track’s producer animal through the analysis of the ichnofossils. It was also possible to prove how the moisture level and the substrate inclination are important for the tracks’ preservation. / Icnofósseis são abundantes nos arenitos da Formação Botucatu, Bacia do Paraná, de idade Neocomiana. Esta formação abrange grande parte do Centro-oeste, Sudeste e Sul do Brasil, além de outros países da América do Sul. Várias amostras de arenito contendo icnofósseis foram coletadas e depositadas na coleção paleontológica do Departamento de Ecologia e Biologia Evolutiva (DEBE) da UFSCar. Neste trabalho foram estudados os icnofósseis atribuídos a aracnídeos, ou seja, os icnogêneros Paleohelcura Gilmore, 1926 e Octopodichnus Gilmore, 1927, registrados pela primeira vez no Brasil. O principal objetivo deste estudo foi identificar como diferentes condições do ambiente, como umidade, textura, inclinação do substrato e até mesmo aspectos comportamentais podem afetar a estrutura dos rastros deixados por diferentes artrópodes. Para isso foram realizados diversos experimentos neoicnológicos com seis aracnídeos (dois Tityus serrulatus, uma Lycosa sp., uma Loxosceles sp., e dois indivíduos da família Gonyleptidae) e cinco indivíduos de outras classes de invertebrados (três insetos, um isópode e um diplópode). Os experimentos consistiram em fazer os animais caminharem sobre uma bandeja com diferentes granulometrias de areia em diferentes inclinações e com diferentes níveis de umidade. Os resultados desses experimentos, que mostraram diferentes formatos dos rastros de acordo com cada condição imposta, comprovaram a influência dessas condições na morfologia das pegadas e no comportamento dos animais estudados. Além disso, esses resultados mostraram como em algumas situações, por exemplo, em um movimento de subida em relevos de 30° de inclinação, é possível que animais com morfologias acentuadamente diferentes deixem rastros muito semelhantes, o que dificulta a identificação do animal produtor por meio da análise de icnofósseis. Também foi possível comprovar como a umidade e a inclinação do substrato são importantes na conservação dos rastros.

The palaeoenvironment from which early tetrapods emerged is crucial to comprehend in order to understand the mechanisms that drove and allowed the terrestrialization of vertebrates; one of the most important evolutionary ‘events’ in the history of animals. Nevertheless, much of the terrestrialization is shrouded in obscurity, inter alia, due to scarcity of early tetrapods in the fossil record. Each new discovery of anything linked to vertebrate terrestrialization is therefore of great importance. Here, I present new detailed analyses of the palaeoenvironmental conditions at the time of formation of the earliest (early Middle Devonian) tetrapod trackways found in the Zachełmie Quarry in the Holy Cross Mountains of southern Poland. The trackways are found in three horizons in a clay-rich dolomitic succession represented by the Lower Complex of the Wojciechowice Formation. This Lower Complex is composed of short shallowing upward sequences that often terminate with desiccation cracks and/or paleosols. Vertically fluctuating δ18O values in the complex suggest multiple episodes of closed hydrological systems. A model of ephemeral to perennial lakes in a terrestrial setting is therefore proposed. Such environment is in concordance with evidence of scarce bioturbation and a flourish of microbial communities that, in contrast to a normal marine setting, most likely represent an ecologically stressed ecosystem. Furthermore: non-marine rare earth element (REE) signals, desiccation events, fossils of green algae (charophytes), paleosol development, low energy cyclic deposits and general lack of marine taxa in the body and trace fossil records in this complex firmly establishes the interpretation of palustrine carbonates formed in a lacustrine-like setting. However, in the lower part of the complex, some highly fractioned marine fossils occur. These are suggested to have been transported during wash-up events which temporally places the setting in marine proximity. Seasons of monsoonal rainfall resulted in erosion and influx of detrital grains which is evidenced by fine planar lamination (of seasonal cyclicity) in most of the sediments and occasional occurrence of blackened clasts (and rain-drop imprints). Thus, none of the pre-existing palaeoenvironmental hypotheses of tetrapod emergence are in full concordance with the data from the Zachełmie Quarry. Instead, a new palaeoenvironment is proposed for the earliest tetrapods: schizohaline ephermal to perennial lakes with periodic desiccation. This infers that already in the early Middle Devonian, tetrapods had conquered the terrestrial realm and were perhaps already capable of terrestrial locomotion over quite substantial distances. / Däggdjur, reptiler, fåglar och amfibier utgör tillsammans en besläktad djurgrupp som kallas för tetrapoder (fyrfotingar). Deras gemensamma förfader härstammade från de lobfenade fiskarna men skiljde sig från dem genom att inneha utvecklade ben med tår istället för de ”köttiga” fenor som de lobfeniga fiskarna karaktäriseras av. Denna evolutionära nyhet tillät, tillsammans med en rad andra egenskaper (lungor, skydd för uttorkning av dermis etc.), att vertebrater helt och hållet kunde koloni-sera land. I och med att vår egen existens är en direkt följd av denna evolutionära händelse är detta ett hett forskningsämne inom evolutionsbiologin. Ändå är mycket fortfarande höljt i dunkel beträffande hur koloniseringen av land gick till och vad det var som drev denna utveckling eftersom övergången skedde under en, i geologisk mått, snabb tidsrymd. Dock har de sista årtiondena resulterat i flertalet nya fossilfynd av primitiva tetrapoder. Ett fynd som är speciellt spektakulärt eftersom det är den hittills äldsta efterlämningen av tetrapoder, är fotspår som uppenbart är gjorda av ett djur som hade ben och tår istället för fenor. Detta förvånade hela det vetenskapliga samfundet eftersom det innebar att vi (tetrapoderna) utvecklades tidigare än vad som var dittills trott och att vertebrat-koloniseringen av land förmodligen skedde flertalet miljoner år tidigare. Vad som också skiljer ett spårfossil från andra fossil är att de är spår av djuren från när och där de levde till skillnad från bara deras skelettdelar som oftast transporterats från där de dog och bara preserveras i speciella miljöer. Detta har jag utnyttjat i detta arbete för att försöka avgöra i vilken miljö de är avsatta i. Jag har analyserat de sedimentära bergarterna i stenbrottet i södra Polen med skärningen som innehåller de lagren i vilka fotspåren finns. Analyser av sällsynta jordartsmetaller från de tre lager där fotspår är tydliga, antyder en speciell avsättningsmiljö som inte liknar en typisk havsmiljö. I den undre delen av lagerföljden där de spårbärande lagren påträffats finns återkristalliserade saltkristaller, torkningssprickor och fossila jordar som indikerar korta respektive långvariga perioder av uttorkning. Andra fossil som i en normal marin miljö borde bevaras i en dolomitisk kalksten lyser med sin frånvaro och istället påfinns massiv koloni-sering av cyanobakterier. Detta brukar ske i speciella miljöer som avviker från vanlig marin komposi-tion, så som äldre sötvattensmiljöer eller laguner med hög salthalt, som därmed är ”svårbebodd” för djur som annars livnär sig på de fotosyntiserande bakterierna. Implikationen av mitt arbete är att tetrapoderna redan i tidig mellan Devon (ca 390 miljoner år sedan) inte bara hade utvecklat ben utan också att de kunde använda dem över landsträckor för att ta sig till, och mellan, kontinentala vatten. Detta är ännu en viktig pusselbit i pusslet som ämnar rekonstruera tetrapodernas (och vår egen) uppkomst.

The Cambrian explosion not only shaped the ecosystems of the Phanerozoic, but fundamentally changed how biota interacts with the environment, including the substrate. Cambrian trace fossils Alectorurus and Syringomorpha as well as Ordovician-Silurian Daedalus represent novel modes of faunal interaction with the newly innovated shallow marine mixed-ground and have surprisingly limited stratigraphic ranges. This study investigates vertically oriented spreiten trace fossils from the Armorican Quartzite Formation near Castañar de Ibor, Spain and the File Haidar Formation near Hällekis, Sweden. Site and trace fossil description was conducted to compare and contrast their morphology, ecological relationships, and potential affinities. While all these fossils feature J-shaped vertically oriented spreiten structures, Alectorurus is the most closely comparable Cambrian ichnofossil to the largely Ordovician Daedalus due to their similarity in overall size, morphology, and sedimentary environment. Alectorurus represents the earliest known occurrence of animal behavior comparable to Daedalus within similar facies. This short-lived ichnofossils may have gone extinct due to complexifying trophic chains in the shallow marine realm as brought forth from heightened predation and land-plant derived organics. Interpretations of the affinity of Daedalus, regarding the construction, and ecological niche can be extended to Alectorurus and may be used to help piece together the construction, ecology and affinities of these enigmatic Cambrian and Ordovician trace fossils.

No description available.

Bibliography: leaves [206]-244.

Bibliography: leaves [206]-244. / xxviii, 244 leaves, [31] leaves of plates : ill. (some col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Geology and Geophysics, 2001

Bibliography: leaves [206]-244. / xxviii, 244 leaves, [31] leaves of plates : ill. (some col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Geology and Geophysics, 2001

No description available.

Submitted by Silvana Teresinha Dornelles Studzinski (sstudzinski) on 2015-07-06T13:35:47Z No. of bitstreams: 1 JoaoLima.pdf: 3825056 bytes, checksum: 17bc443c02a042f3194ce14358ee935d (MD5) / Made available in DSpace on 2015-07-06T13:35:47Z (GMT). No. of bitstreams: 1 JoaoLima.pdf: 3825056 bytes, checksum: 17bc443c02a042f3194ce14358ee935d (MD5) Previous issue date: 2010 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / CNPQ – Conselho Nacional de Desenvolvimento Científico e Tecnológico / PROSUP - Programa de Suporte à Pós-Gradução de Instituições de Ensino Particulares / Este estudo analisa e caracteriza a paleoicnologia dos depósitos da Formação Teresina aflorantes no Cerro Caveiras (Dom Pedrito, RS), com a intenção de refinar as interpretações paleoecológicas e paleoambientais existentes. A icnofauna dos depósitos analisados é composta por Bergaueria isp., Cochlichnus anguineus, Cruziana problematica, Diplocraterion isp., Diplopodichnus biformis, Helminthopsis isp., Lockeia siliquaria, Multina minima, Palaeophycus striatus, Palaeophycus tubularis, Planolites beverleyensis, Planolites montanus, Scolicia cf. plana, Teichichnus isp. e Thalassinoides isp. Esta assembléia foi dividida em duas suítes, uma delas sinalizando colonização em ambiente de água salobra e a outra reunindo estruturas que sugerem colonização em ambiente de água doce. Cinco fácies sedimentares foram descritas: (i) fácies de lamito; (ii) fácies de arenito fino com estratificação cruzada cavalgante; (iii) fácies de heterolito; (iv) fácies de arenito com estratificação cruzada acanalada e; (v) fácies de arenito fino a médio com estratificação cruzada hummocky (HCS) ou swalley (SCS). Estruturas sedimentares geradas por ondas dominam a sucessão e as associações de fácies sugerem deposição em zona de shoreface inferior/transição ao offshore. Feições geradas pela ação de correntes também são comuns. A recorrente substituição da suíte de água salobra pela suíte de água doce e a manutenção desta por mais tempo ao longo da sucessão indica significativo aporte de água doce no sistema. Esse padrão, aliado ao estabelecimento da suíte de água doce sempre após a deposição das fácies indicativas da ação de correntes sugere a influência de depósitos deltaicos na zona de shoreface inferior, em um contexto marinho raso restrito. Duas superfícies estratigráficas são sugeridas pela análise da icnofauna, uma co-planar (S1), composta por, pelo menos, uma superfície de erosão regressiva e uma superfície transgressiva, e uma de inundação (S2), que marca o momento de maior profundização e de maior teor de salinidade do sistema, na área de estudo. A integração dos dados icnológicos e sedimentológicos do Cerro Caveiras sugere que esta sucessão sedimentar possivelmente represente deposição em frentes deltaicas distais retrabalhadas por ondas. / This study analyzes and characterizes the paleoichnology of the Teresina Formation sedimentary rocks cropping out in Cerro Caveiras (Dom Pedrito, Rio Grande do Sul State, south of Brazil), aiming to refine the existing paleoecological and paleoenvironmental interpretations. The ichnofauna is composed of Bergaueria isp., Cochlichnus anguineus, Cruziana problematica, Diplocraterion isp., Diplopodichnus biformis, Helminthopsis isp., Lockeia siliquaria, Multina minima, Palaeophycus striatus, Palaeophycus tubularis, Planolites beverleyensis, Planolites montanus, Scolicia cf. plana, Teichichnus isp. and Thalassinoides isp., distributed in two main trace fossil suites, a brackish-water suite and a freshwater suite. Five sedimentary facies were described: (i) laminated or massive shale; (ii) fine-grained sandstone with climbing ripples; (iii) heterolithic deposits; (iv) trough crossstratified sandstone; and (v) hummocky and swalley cross-stratified sandstone. Wavegenerated structures predominates and facies associations suggest deposition in lower shoreface/offshore transition setting. Current-generated structures are also common. The recurrent replacement of brakish-water suite by freshwater suite and the maintenance of the last one for more time in the sedimentary succession suggest a significative input of freshwater into the marine zones. This pattern, and the fact that freshwater suite settlement always occur after the current-generated sandstone deposition suggest deltaic influence in the lower shoreface, in a restricted shallow sea context. Two stratigraphic surfaces should be inferred by trace fossil analysis: a co-planar surface (S1), composed of a regressive erosion surface and a transgressive surface, at least, and a flooding surface (S2), which marks the deepest and saltiest episode in the depositional system at the study area. The integrated analysis involving the ichnology and sedimentology of the Cerro Caveiras succession suggest that it possibly represents a distal expression of wave-dominated delta fronts.