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  • 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.
11

Estudo tafonômico de afloramentos contendo vertebrados fósseis das Bacias do Iguatu, Cretáceo Inferior, nordeste do Brasil

Figueiredo, Ana Emilia Quezado de January 2009 (has links)
Alguns afloramentos das bacias de Icó, Malhada Vermelha e Lima Campos(Cretáceo Inferior), Estado do Ceará, foram estudados objetivando compreender os ambientes deposicionais onde foram preservados os fósseis de vertebrados.Estes fósseis encontram-se desarticulados e fragmentados, entre outras características. Através do levantamento destes dados, foi possível estabelecer modelos tafonômicos para cada afloramento, e, tentativamente, distinguir os diversos modos de preservação destes restos fossilizados. Observou-se que o padrão de formação destas tafocenoses está relacionado a ambientes altamente energéticos, como em depósitos relacionados a eventos de rompimento de diques marginais (crevasse splay), onde elementos que já se encontravam desarticulados eram transportados, causando a intensa fragmentação dos mesmos. / Some outcrops from Icó, Malhada Vermelha and Lima Campos basins (Early Cretaceous), State of Ceará, were studied for a better understanding of the depositional systems where vertebrate fossils were preserved. These fossils were found disarticulated, fragmented, among others features. Through of these data, it was possible to determinate taphonomic models for each outcrop, and, tentatively, to distinguish the different ways of preservation of those fossils. It was observed that the formation pattern of those taphocenoses are related with highly energetic environments, like crevasse splay, where the disarticulated elements were transported, causing the intense fragmentation of the bones.
12

Tafonomia de moluscos com ênfase em Sistemas Estuarino-Lagunares da Planície Costeira do Rio Grande do Sul, Brasil

Ritter, Matias do Nascimento January 2013 (has links)
Acumulações de restos de moluscos são muito comuns tanto em ambientes marinhos plataformais quanto em depósitos lagunares e estuarinos da América do Sul, principalmente entre o Brasil e a Argentina. A formação destas concentrações conchíferas pode prover grande oportunidade para estudos tafonômicos, os quais ainda são raros nesta região. Existem ainda questões a serem respondidas, por exemplo, quanta informação biológica está preservada nestas concentrações? Ou, qual é a probabilidade de uma associação viva deixar um registro fóssil análogo? Os principais objetivos deste estudo foram: (i) investigar a influência dos processos ambientais na destruição de remanescentes biológicos, através da descrição das assinaturas tafonômicas presentes em conchas de moluscos de dois afloramentos da Laguna Tramandaí, nordeste do Rio Grande do Sul; e (ii) testar o potencial de preservação de associações de moluscos vivos, mortos e fósseis de lagunas e estuários da Planície Costeira do Rio Grande do Sul, com o intuito de compreender a qualidade da informação biológica preservada nestas associações fósseis de fácies lagunares holocênicas. O principal processo tafonômico é a dissolução. As conchas estão inseridas na zona tafonomicamente ativa e experimentam intensa dissolução, o que reduz a probabilidade de deixarem um registro fóssil. Todavia, a preservação de espécies da associação viva nos depósitos fósseis foi de 100% em nível regional, e as espécies presentes na associação morta não apresentaram boa preservação no registro fóssil recente (Holoceno), ao contrário do que é usualmente predito na bibliografia. Isso indica que a associação morta é enriquecida por espécies não indígenas, e parte deste aumento relativo da riqueza é transferida para a associação fóssil. O padrão observado na fidelidade de moluscos estuarinos é ocasionado pela (i) alta variabilidade temporal e espacial nas associações vivas, (ii) mistura espacial nas associação mortas e (iii) preservação diferencial, devido à destruição durante uma longa permanência na zona tafonomicamente ativa. Portanto, a dissolução é o principal processo tafonômico que altera a informação biológica em ambientes transicionais, embora a preservação seletiva possa introduzir vieses das associações vivas às fósseis. / Molluscan shell accumulations (shell beds) are very common in shallow marine and estuarine environments in South America and also on the continental shelf from Southern Brazil through Argentina. The development of these shell beds can provide a great opportunity to taphonomic studies, which are uncommon in this geographic location. For example, how much biological information is preserved within these shell beds? Or, what is the actual probability a local living community has to leave a fossil record corresponding to these shell deposits? The aims of this study are (i) to investigate the influence of environmental processes on the destruction of biological remains in a subtropical lagoonal setting by describing the taphonomic signatures occurring in the mollusk shells from the Tramandaí Lagoon, northeastern Rio Grande do Sul State; and (ii) to compare living assemblages (LAs), death assemblages (DAs) and fossil assemblages (FAs) from estuaries and lagoons in the Rio Grande do Sul Coastal Plain to understand the nature and quality of biological information preserved in fossil associations in Holocene lagoon facies. Dissolution appears to be a leading taphonomic agent in lagoonal environments according to the study. The shells are within the taphonomically active zone and, due to intense dissolution, they will most likely leave no geological record. Nonetheless, the preservation of living species in FA was 100% and species present in DA are not as good preserved in recent (Holocene) fossil record as originally thought from the literature. The present results indicate that both DAs and FAs from estuarine-lagoons environments are composed basically by nonindigenous species, with live-dead mismatch than for continental shelves. The fidelity pattern here observed for estuarine mollusks have been driven by (i) high temporal and spatial variability in the LAs, (ii) spatial mixing in the DAs and (iii) differential preservation of shells, due to long residence times in the taphonomically active zone. Dissolution is the main taphonomic process altering biological information in those environments, but differential preservation may be, perhaps, the responsible for introducing bias from living to fossil assemblages.
13

Estudo tafonômico de afloramentos contendo vertebrados fósseis das Bacias do Iguatu, Cretáceo Inferior, nordeste do Brasil

Figueiredo, Ana Emilia Quezado de January 2009 (has links)
Alguns afloramentos das bacias de Icó, Malhada Vermelha e Lima Campos(Cretáceo Inferior), Estado do Ceará, foram estudados objetivando compreender os ambientes deposicionais onde foram preservados os fósseis de vertebrados.Estes fósseis encontram-se desarticulados e fragmentados, entre outras características. Através do levantamento destes dados, foi possível estabelecer modelos tafonômicos para cada afloramento, e, tentativamente, distinguir os diversos modos de preservação destes restos fossilizados. Observou-se que o padrão de formação destas tafocenoses está relacionado a ambientes altamente energéticos, como em depósitos relacionados a eventos de rompimento de diques marginais (crevasse splay), onde elementos que já se encontravam desarticulados eram transportados, causando a intensa fragmentação dos mesmos. / Some outcrops from Icó, Malhada Vermelha and Lima Campos basins (Early Cretaceous), State of Ceará, were studied for a better understanding of the depositional systems where vertebrate fossils were preserved. These fossils were found disarticulated, fragmented, among others features. Through of these data, it was possible to determinate taphonomic models for each outcrop, and, tentatively, to distinguish the different ways of preservation of those fossils. It was observed that the formation pattern of those taphocenoses are related with highly energetic environments, like crevasse splay, where the disarticulated elements were transported, causing the intense fragmentation of the bones.
14

Tafonomia de moluscos com ênfase em Sistemas Estuarino-Lagunares da Planície Costeira do Rio Grande do Sul, Brasil

Ritter, Matias do Nascimento January 2013 (has links)
Acumulações de restos de moluscos são muito comuns tanto em ambientes marinhos plataformais quanto em depósitos lagunares e estuarinos da América do Sul, principalmente entre o Brasil e a Argentina. A formação destas concentrações conchíferas pode prover grande oportunidade para estudos tafonômicos, os quais ainda são raros nesta região. Existem ainda questões a serem respondidas, por exemplo, quanta informação biológica está preservada nestas concentrações? Ou, qual é a probabilidade de uma associação viva deixar um registro fóssil análogo? Os principais objetivos deste estudo foram: (i) investigar a influência dos processos ambientais na destruição de remanescentes biológicos, através da descrição das assinaturas tafonômicas presentes em conchas de moluscos de dois afloramentos da Laguna Tramandaí, nordeste do Rio Grande do Sul; e (ii) testar o potencial de preservação de associações de moluscos vivos, mortos e fósseis de lagunas e estuários da Planície Costeira do Rio Grande do Sul, com o intuito de compreender a qualidade da informação biológica preservada nestas associações fósseis de fácies lagunares holocênicas. O principal processo tafonômico é a dissolução. As conchas estão inseridas na zona tafonomicamente ativa e experimentam intensa dissolução, o que reduz a probabilidade de deixarem um registro fóssil. Todavia, a preservação de espécies da associação viva nos depósitos fósseis foi de 100% em nível regional, e as espécies presentes na associação morta não apresentaram boa preservação no registro fóssil recente (Holoceno), ao contrário do que é usualmente predito na bibliografia. Isso indica que a associação morta é enriquecida por espécies não indígenas, e parte deste aumento relativo da riqueza é transferida para a associação fóssil. O padrão observado na fidelidade de moluscos estuarinos é ocasionado pela (i) alta variabilidade temporal e espacial nas associações vivas, (ii) mistura espacial nas associação mortas e (iii) preservação diferencial, devido à destruição durante uma longa permanência na zona tafonomicamente ativa. Portanto, a dissolução é o principal processo tafonômico que altera a informação biológica em ambientes transicionais, embora a preservação seletiva possa introduzir vieses das associações vivas às fósseis. / Molluscan shell accumulations (shell beds) are very common in shallow marine and estuarine environments in South America and also on the continental shelf from Southern Brazil through Argentina. The development of these shell beds can provide a great opportunity to taphonomic studies, which are uncommon in this geographic location. For example, how much biological information is preserved within these shell beds? Or, what is the actual probability a local living community has to leave a fossil record corresponding to these shell deposits? The aims of this study are (i) to investigate the influence of environmental processes on the destruction of biological remains in a subtropical lagoonal setting by describing the taphonomic signatures occurring in the mollusk shells from the Tramandaí Lagoon, northeastern Rio Grande do Sul State; and (ii) to compare living assemblages (LAs), death assemblages (DAs) and fossil assemblages (FAs) from estuaries and lagoons in the Rio Grande do Sul Coastal Plain to understand the nature and quality of biological information preserved in fossil associations in Holocene lagoon facies. Dissolution appears to be a leading taphonomic agent in lagoonal environments according to the study. The shells are within the taphonomically active zone and, due to intense dissolution, they will most likely leave no geological record. Nonetheless, the preservation of living species in FA was 100% and species present in DA are not as good preserved in recent (Holocene) fossil record as originally thought from the literature. The present results indicate that both DAs and FAs from estuarine-lagoons environments are composed basically by nonindigenous species, with live-dead mismatch than for continental shelves. The fidelity pattern here observed for estuarine mollusks have been driven by (i) high temporal and spatial variability in the LAs, (ii) spatial mixing in the DAs and (iii) differential preservation of shells, due to long residence times in the taphonomically active zone. Dissolution is the main taphonomic process altering biological information in those environments, but differential preservation may be, perhaps, the responsible for introducing bias from living to fossil assemblages.
15

Změny vnějších povrchů koster dolních končetin způsobené tafonomickými faktory: Pohansko, 2. kostel / Changes in the external surfaces on the lower limb bones caused by taphonomic factors: Pohansko, 2nd church

Vitnerová, Tereza January 2020 (has links)
Changes in the external surfaces on the lower limb bones can be caused by various taphonomic factors. It is important for our work how these changes will affects. The aim of the work was to process and subsequently evaluate the changes in the external surfaces on the lower limb bones. For analyses we chose set of adults from 2nd church burial ground Pohansko near Břeclav, we chose specifically braid of the lower limbs (cingulum membri inferioris) and free lower limb (pars libera membri inferioris). We wrote down taphonomic changes into prepared protocols, changes were typologically about damages and color changes. We used programs InkScape and AdobePhotoshop to transform paper protocols into digital form. Heat maps are outputs from this programms through them we are able to see incidence rate of individual changes. We most often detected the occurrence of an orange color on the bones of the lower limbs, so we focused on its cause. We found an increased content of silicon and aluminum in its chemical composition, so we assume that it could be an aluminosilicate weathering product. Key words: Pohansko, taphonomy, taphonomic factors, bone surface, lower limb
16

Vliv morfometrických a mikrostrukturálních charakteristik na rozklad ulit plžů v lesních ekosystémech / The influence of morphological and microstructural characteristics to land snail degradation in forest environment

Říhová, Dagmar January 2018 (has links)
The decomposition of land snail shell is a complex process involving a number of factors and influences, including the characteristics of conchs themselves. In particular, it is the shell size with which the progress and the rate of degradation are tightly bound. Post-mortem changes begin with the loss of the original colour and, in the case of transparent species, by the opacification of the shell wall. Subsequently, the periostracum disruption and dissolution of calcium layers occur. However, this sequence may be reversed for some small species (e.g. Columella aspera, Nesovitrea hammonis). Animals mechanically destroy empty shells, humic acids from the substrate cause their artificial dyeing. Fungal mycelium or colonies of Streptomyces grow on the surface of the conchs. The plant roots are also involved in shell decomposition. While degradation of large shells starts with periostracum disruption and subsequent ostracal dissolution, periostracum of small shells persists even after dissolution of ostracal layers. The phenomenon is caused by high resistance of the periostraca of small species. In the case of large shells, periostracum has primarily a "building" function during shell formation, and sometimes it is flaking off already during the snail's life. For small species, it is an important part...
17

Sedimentologic and taphonomic analysis of a 1945 tsunami deposit in Sur Lagoon, Sultanate of Oman

Donato , Simon Vincent 01 1900 (has links)
The Sultanate of Oman is a rapidly modernizing country with a significant length of its coastline slated for development. Much of the coastline is still in its natural state and basic studies describing the sedimentary systems need to be conducted in order to plan effectively for their sustainable development and to monitor changes in them with time. For such purposes, sediment samples (surface and sub-surface), elevation data, and serial sediment cores were collected at Sur Lagoon during three field seasons. The research objectives, procedures, results, and analyses for Sur lagoon are presented in three chapters. The first chapter compares textural facies, identified on the basis of particle-size distribution (PSD) of surface sediments from Sur Lagoon and evaluated using multi-variate cluster analysis, for their value in recognizing modem sedimentary environments. Clustering the full PSD size spectrum (0.0375- 1888 μm) shows that facies identification is possible is closely tied to surface elevation, particle-size decreasing with increasing elevation above mean sea level. This analytical technique should be tested under different conditions to assess further its utility. The second chapter discusses the taphonomically distinct and laterally extensive (> 1 km2) bivalve shell bed deposited by a tsunami on November 28th, 1945. Taphonomic characteristics of this unit are compared to those of the shell-rich tsunamite from Caesarea, Israel, and resulted in the identification of three generic, tsunamigenic-specific traits in shell beds: 1) thickly bedded and laterally extensive shell deposit, 2) presence of allochthonous articulated bivalves not in life position, and 3) extensive angular fragmentation. When these three traits are found together, a tsunamigenic origin should be considered for the shell bed. The third chapter analyzes the PSD of the tsunamite in eight sediment cores for digested and undigested samples. Cluster analysis of the PSD extended the upper or lower tsunamite contacts in four cores, but in general, the tsunamite thickness is consistent with the previously identified shell beds (Chapter 3). The tsunamigenic processes that resulted in the deposition of the shell bed were complex, and deposition occurred during run-up, flooding, and backwash stages of the tsunami, incorporating marine, lagoonal, and terrestrial (wadi) sediment into the tsunamite. The results of this study provide baseline sedimentological data for an understudied region of the world. New applications of cluster analysis of PSD and taphonomic analysis have the potential to identify previously unknown tsunamites in the geological record, and lithological facies using textural analysis. / Thesis / Doctor of Philosophy (PhD)
18

The prevalence of pathological and taphonomic change of skeletal remains from the Winchester Site

Swift, Kacy 30 January 2024 (has links)
The present research examines the pathological changes and taphonomic alterations of buried human skeletal remains discovered in a burial feature underneath a construction site in a neighborhood house in Winchester, Massachusetts. Artifact association places the burial of these remains around the mid 1800s. Pathological changes were observed based on the presence of bone formation or destruction. The manifestations of pathological change observed for were related to or consistent with joint disease, infectious diseases, metabolic disorders, congenital abnormalities, dental disease, and neoplastic conditions. Taphonomic profiles of buried remains display certain characteristics that can be used to make comparisons to other known burial types, specifically traditional cemetery burials. The characteristics observed for to create the taphonomic profile were soil and mineral staining, bone condition and preservation, plant adherence and/or damage, postmortem damage, and the presence of coffin artifacts. The author hypothesized that the current sample of human skeletal remains from the Winchester Site would display pathological changes consistent with individuals from marginalized populations of the nineteenth century. The most prevalent pathological changes in the sample were those related to osteoarthritis (OA) and infection. The vertebral elements were most affected by OA, at 24.0% on the vertebral bodies and 17.5% on the vertebral facets. Of the remaining elements scored for OA, only 7.1% showed characteristics. Infection was observable on 10.9% of the postcranial elements, with the fibulae being the most affected, at 20.9%, followed by the tibiae at 18.3% and the clavicles at 16.1%. There were more cases of sclerotic bone, which indicated that the healing process started prior to death. There were only 11 cases of antemortem trauma that were observed to be either in the process of healing or already healed, as well as 2 cases of healed amputations of two proximal row pedal phalanges. Dentition was most affected by calculus at 33.3%, and had little instances of linear enamel hypoplasias. Other miscellaneous pathological changes were also observed, including Schmorl’s nodes, PH/CO, HFI, possible neoplasms, possible tuberculosis, and exostoses of the mouth. It was also hypothesized that the skeletal remains would display a different taphonomic profile compared to previously researched profiles of anatomized and cemetery remains. There is ubiquitous soil staining throughout the sample, postmortem damage at 69.4%, moderate cortical erosion at 15.7%, slight plant root adherence at 8.3%, and low mineral staining at 5.3%. There is a lack of anatomical hardware present throughout the remains, which indicates that the remains were not used for anatomical teaching. There is an abnormal pink stain on 1.0% of the skeletal remains, possibly the result of a historical embalming technique that used mercury. The analysis of the skeletal remains from the Winchester Site supported the hypothesis that the remains would display pathological changes consistent with marginalized populations. The author compared the Winchester Site to sites that reported having anatomized remains of marginalized individuals, specifically sites that were used as medical waste sites, poorhouses, and almshouses. The analysis of the skeletal remains also supported the hypothesis that the remains would display a taphonomic profile more consistent with cemetery remains buried directly in the soil and secondarily determined that the site was likely used as a medical waste site of anatomized remains. The analysis of the Winchester Site also confirmed that the remains did not display a taphonomic profile related to coffin cemetery remains or remains that have been prepared and used for anatomical teaching.
19

Disarticulation and Dissolution of Crab Remains Across a Depth Gradient in the Bahamas : A Taphonomic Study

Lincoln, Rebecca A. January 2000 (has links)
No description available.
20

Bad-Boy Bryozoan Biomarkers : Cheilostome Distribution Patterns Along a Bahamian Depth Gradient

Nytch, Christopher J. January 2000 (has links)
No description available.

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