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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.
81

Caracterização tafonômica das concentrações fossilíferas da Formação Cape Melville, Grupo Moby Dick (Mioceno Inferior), Ilha Rei George, Antártica / Taphonomic characterization of fossil concentrations from the Cape Melville Formation, Moby Dick Group (Early Miocene), King Georg Island, Antactica

Casati, Rafael 01 November 2007 (has links)
Trabalhos objetivando a tafonomia de concentrações fossilíferas geradas em ambiente glacial ou periglacial são raros. Neste contexto, a presente dissertação realizou a caracterização tafonômica das concentrações fossilíferas da Formação Cape Melville, Grupo Moby Dick (Mioceno Inferior), Ilha Rei George, Antártica, tendo em vista a elucidação da gênese destes depósitos. Para tanto, dados relativos a um total de 534 espécimes foram obtidos nas camadas ricamente fossilíferas das quatro seções, denominadas Pingüineira (PRS), Hard Ground (HGS), Chaminé (CS) e Lava Crag (LCS), levantadas no topo da Península Melville entre Janeiro e Fevereiro de 2003. Destas, apenas a Seção PRS apresenta duas camadas fossilíferas distintas (PRS-C1 e PRS-C2). A fauna estudada é composta predominantemente por restos de moluscos bivalves. Restos menos abundantes de corais, caranguejos, gastrópodes e braquiópodes, além de icnofósseis, também estão presentes. A análise da composição taxonômica, ecológica e tafonômica permitiu identificar semelhanças entre as Seções PRS e HGS e entre as Seções CS e LCS. As seções PRS e HGS são compostas dominantemente por bivalves depositívoros da infauna rasa (Ennucula frigida, Enncula musculosa e Yoldia peninsularis), preservados preferencialmente com as valvas articuladas fechadas, porém fora da posição de vida, indicando remobilização da fauna pré-soterramento; a ausência de sinais de fragmentação, abrasão e incrustação indica que os bioclastos não foram afetados por processos bioestratinômicos químicos, físicos ou biológicos intensos. A ocorrência de bioclastos piritizados na Seção HGS é interpretada como resultante da decomposição dos organismos soterrados, ainda vivos, em ambiente anóxico. As assembléias das seções CS e LCS são constituídas dominantemente por bivalves suspensívoros da infauna profunda (Neilo (N.) rongelii), preservados preferencialmente com as valvas desarticuladas, indicando que os processos bioestratinômicos físicos foram mais atuantes, sendo, no entanto, raros os sinais de fragmentação e de outras assinaturas tafonômicas como incrustação e bioerosão. As valvas desarticuladas estão preservadas preferencialmente com a convexidade voltada para baixo indicando que os bioclastos foram colocados em suspensão e redepositados fora da posição de maior estabilidade hidrodinâmica; a orientação em planta destes bioclastos exibe direção preferencial, indicando atuação de correntes fracas e um maior tempo de exposição na interface água/sedimento; a ocorrência de raros restos de bivalves suspensívoros escavadores da infauna profunda (Panopea (P.) cf. P. regularis) e de caranguejos (Antarctidromia inflata) preservados em posição de vida é indicativa de que esta comunidade foi soterrada in situ por sedimentos em suspensão que trouxeram a tanatocenose de valvas desarticuladas. Os resultados obtidos no presente estudo reiteram a importância dos estudos tafonômicos e paleoecológicos no entendimento da dinâmica deposicional do passado, contribuindo com um grande conjunto de dados úteis na caracterização de ambientes glaciais e periglaciais. / Works focusing on the taphonomy of fossil concentrations generated in glacial or periglacial environment are rare. In this context, the present dissertation carried out the taphonomic characterization of the fossil concentrations of the Cape Melville Formation, Moby Dick Group (Lower Miocene), King George Island, Antarctica, in order to elucidate the genesis of these deposits. To this end, data relative to a total of 534 specimens were obtained in the richly fossil layers of the four sections, called Pingüineira (PRS), Hard Ground (HGS), Chaminé (CS) and Lava Crag (LCS), investigated at the top of the Melville Peninsula between January and February of 2003. Of these, only the PRS Section presents two distinct fossil layers (PRS-C1 and PRS-C2). The studied fauna is mainly composed of remains of bivalve clams. Less abundant remains of corals, crabs, gastropods and brachiopods, as well as trace fossils, also are present. Taxonomic, ecological and taphonomic analyses allowed similarities to be identified between PRS and HGS and CS and LCS. PRS and HGS Sections are dominantly composed by shallow infaunal deposit-feeding bivalves (Ennucula frigida, Enncula musculosa Yoldia peninsularis), preserved preferentially with closed articulated valves, however out of life position, indicating remobilized fauna; the absence of signs of spalling, abrasion and incrustation indicates that the bioclasts were not affected by intense chemical, physical or biological bioestratinomic processes. The occurrence of pyritized bioclasts in HGS is interpreted as the result of decomposition of the entombed organisms, still alive, in an anoxic environment. The assemblages of CS and LCS Sections are dominantly constituted by deep infaunal suspension-feeding bivalves (Neilo (N.) rongelii), preserved preferentially with disarticulated valves, indicating that the physical biostratinomic processes were more operative; however there are few signs of spalling or other taphonomic signatures such as incrustation and bioerosion. Disarticulated valves are preferentially preserved convex down indicating that bioclasts were placed in suspension and redeposited in a position other than that of greatest hydrodynamic stability; the orientation of these bioclasts in plan view shows a preferential direction, indicating weak currents and a longer time of exposition at the water/sediment interface; the occurrence of rare remains of deep infaunal suspension-feeding bivalves (Panopea (P.) cf. P. regularis) and crabs (Antarctidromia inflata) preserved in life position is indicative that this community was entombed in situ by sediments in suspension that brought the thanatocenosis of disarticulated valves. The results obtained in the present study reiterate the importance of taphonomic and paleoecological studies for the understanding of the depositional dynamics of the past and contribute a great number of data useful in the characterization of glacial and periglacial environments.
82

A Paleontological Analysis of Late Pleistocene Proboscidea from Saltville, Virginia: Taphonomy, Systematic Paleontology, and Paleobiology

Silverstein, Rachel 01 May 2017 (has links)
Saltville, Virginia (Smyth County and Washington County) has been known for its late Pleistocene megafauna since the 1700s. Based on reviews of past excavations and material in collections, the most prominent fossils found at Saltville are proboscideans. Teeth of Mammuthus (mammoth) and Mammut (mastodon) from East Tennessee State University Museum of Natural History, Virginia Museum of Natural History, and Smithsonian were the focus of this research. Evidence of sedimentary abrasion and degree of concretion development was used to address the taphonomic history of the assemblage. Evidence of root resorption, tooth expectoration, and eruption and wear of proboscidean molars was used to understand age-related patterns in the proboscidean assemblage. The Saltville proboscidean assemblage contains a disproportionate amount of juvenile mammoth and mastodon teeth, some of which were lost in life. This assemblage has also been modified extensively by sedimentary abrasion.
83

Hunting Specialisation and the Broad Spectrum Revolution in the Early Epipalaeolithic: Gazelle Exploitation at Urkan e-Rubb IIa, Jordan Valley

Humphrey, Emma 22 August 2012 (has links)
This present research explores the impact of Flannery’s (1969) Broad Spectrum Revolution model within the context of the Levantine Epipalaeolithic, specifically the early (Kebaran) Epipalaeolithic. This model attempts to explain changes in subsistence behaviour associated with the end of the Pleistocene leading up to the development of agriculture. The Jordan valley represents an ideal model for Flannery’s marginal habitat because of the range of different flora and fauna required more intensive resource exploitation strategies. The discussion here focuses on the zooarchaeological and taphonomic analysis of two faunal assemblages (representing two sub-horizons) from Urkan e-Rubb IIa, a Kebaran site located in the lower Jordan Valley, and excavated by E. Hovers (Institute of Archaeology, Hebrew University Jerusalem), in 1986 and 1988. This site shows evidence of specialised gazelle hunting and processing. Initial interpretations of the site argued for a multi-purpose residential base camp, supported by lithic tool and shell bead manufacturing. Recent discussions of Epipalaeolithic diet breadth have concentrated on the end of the Pleistocene (Munro 2001, 2003, 2004, 2009; Stiner 2001; Stiner & Munro 2002; Stiner et al. 1999, 2000; Stutz et al. 2009) and have been directed towards explaining changing subsistence patterns towards the end of the Epipalaeolithic (i.e. the Natufian), where an increased use of wild cereals and small game has been well documented. The view that it is not until the Natufian that broad spectrum resource strategies were used is questioned here. Major questions that are addressed with this research include: What do the faunal assemblages from Urkan e-Rubb IIa tell us about Kebaran subisistence behaviour? Do broad spectrum models help to shed light on subsistence adaptations at the end of the Last Glacial Maximum? What can recent analyses of Jordan Valley faunal assemblages contribute to the discussion? These are addressed through a detailed zooarchaeological and taphonomic analysis of the Urkan e-Rubb IIa fauana, followed by synchronic and diachronic analyses of Levantine Epipalaeolithic assemblages, through a combination of taxonomy-based diversity indices and prey-ranking indices.
84

Hunting Specialisation and the Broad Spectrum Revolution in the Early Epipalaeolithic: Gazelle Exploitation at Urkan e-Rubb IIa, Jordan Valley

Humphrey, Emma 22 August 2012 (has links)
This present research explores the impact of Flannery’s (1969) Broad Spectrum Revolution model within the context of the Levantine Epipalaeolithic, specifically the early (Kebaran) Epipalaeolithic. This model attempts to explain changes in subsistence behaviour associated with the end of the Pleistocene leading up to the development of agriculture. The Jordan valley represents an ideal model for Flannery’s marginal habitat because of the range of different flora and fauna required more intensive resource exploitation strategies. The discussion here focuses on the zooarchaeological and taphonomic analysis of two faunal assemblages (representing two sub-horizons) from Urkan e-Rubb IIa, a Kebaran site located in the lower Jordan Valley, and excavated by E. Hovers (Institute of Archaeology, Hebrew University Jerusalem), in 1986 and 1988. This site shows evidence of specialised gazelle hunting and processing. Initial interpretations of the site argued for a multi-purpose residential base camp, supported by lithic tool and shell bead manufacturing. Recent discussions of Epipalaeolithic diet breadth have concentrated on the end of the Pleistocene (Munro 2001, 2003, 2004, 2009; Stiner 2001; Stiner & Munro 2002; Stiner et al. 1999, 2000; Stutz et al. 2009) and have been directed towards explaining changing subsistence patterns towards the end of the Epipalaeolithic (i.e. the Natufian), where an increased use of wild cereals and small game has been well documented. The view that it is not until the Natufian that broad spectrum resource strategies were used is questioned here. Major questions that are addressed with this research include: What do the faunal assemblages from Urkan e-Rubb IIa tell us about Kebaran subisistence behaviour? Do broad spectrum models help to shed light on subsistence adaptations at the end of the Last Glacial Maximum? What can recent analyses of Jordan Valley faunal assemblages contribute to the discussion? These are addressed through a detailed zooarchaeological and taphonomic analysis of the Urkan e-Rubb IIa fauana, followed by synchronic and diachronic analyses of Levantine Epipalaeolithic assemblages, through a combination of taxonomy-based diversity indices and prey-ranking indices.
85

Investigations of human gnawing on small mammal bones among contemporary Bofi foragers of the Central African Republic /

Landt, Matthew John, January 2004 (has links) (PDF)
Thesis (M.A. in anthropology)--Washington State University, 2004. / Title from PDF t.p. (viewed on Nov. 6, 2005). Includes bibliographical references (p. 126-140).
86

Effects of a Shallow-Water Hydrothermal Vent Gradient on Benthic Calcifiers, Tutum Bay, Ambitle Island, Papua New Guinea

Engel, Brienne E. 12 August 2010 (has links)
Ocean acidification is occurring in response to rapidly increasing concentrations of atmospheric CO2. Shallow-water hydrothermal vent systems have been proposed as natural laboratories for studying the effects of elevated pCO2 on benthic communities. Hydrothermal vents occur at depths of approximately 10m in Tutum Bay, Ambitle Island, Papua New Guinea; these vents are surrounded by a typical-appearing fringing coral-reef community. Groups of live specimens of seven species of reef-dwelling, larger benthic foraminifers, along with segments of calcareous green algae broken from live thalli, were collected from a reef location, placed in small mesh bags, and deployed for five days at six different sites along a gradient of temperature (29.6oC-59.3oC) and pH (5.9-8.1) with distance from a large hydrothermal vent in Tutum Bay. Foraminiferal taxa used in the experiment included Amphisorus hemprichii, a species with Mg-calcite porcelaneous shells, three species of Amphistegina that produce hyaline calcite shells, and three species with hyaline Mg-calcite shells (Heterostegina depressa and two Calcarina spp.). Several specimens of four of the seven foraminiferal species examined survived exposure to elevated temperatures of 59.3oC and low pH of 6.2 for five days, while at least one specimen of each of the seven species survived exposure to 39.9oC and pH 5.9. Examination of shells at 600-1000x magnification using scanning electron microscopy revealed fine-scale dissolution in specimens up to 30m from the vent. Results of this experiment, as well as previously reported observations from the study site, indicate that the calcifying reef-dwelling organisms examined can survive pH extremes that result in dissolution of their shells following death.
87

The Isolated Human Bone From Grasshopper Pueblo (AZ P:14:1[ASM])

Margolis, Michael Martin January 2007 (has links)
This paper presents research on isolated human remains from Grasshopper Pueblo and analyzes the processes by which bone becomes displaced from burials. Isolated human bone has never been systematically examined, which represents a significant gap in the study of the prehistoric American Southwest. This research is important because it is the first determination of the pattern of isolated bone found at an archaeological site and the formation processes that are responsible. It is also relevant for the creation of a standard isolated bone methodology and because it enables a better understanding of burial assemblages and anomalous assemblages of culturally modified bone.Subadults dominate the assemblage and larger elements are better represented than smaller elements. Most of the modifications present are postmortem but perimortem breakage and toolmarks are also present. This research produced a baseline of detailed data on isolated human bone in which patterns and anomalies can be inferred; the results suggest multiple causes of the isolation of the specimens, including prehistoric cultural disturbance, rodent disturbance, and the process of excavation.
88

Using drilled-undrilled shell damage analysis to estimate crushing predation frequencies in modern marine gastropod assemblages

Stafford, Emily S. Unknown Date
No description available.
89

Determining the impact of carrion decomposition on soil microbial activity levels and community composition.

Breton, Heloise 01 December 2013 (has links)
The ubiquitous nature of microorganisms and their specificity to certain locations make them potentially useful for forensic investigators. Advances in microbial profiling techniques have made it possible to compare microbial community profiles obtained from evidence or crime scenes to individuals and vice versa. Profiling microbial communities associated with cadaver decomposition may provide useful information concerning post-mortem intervals and aid in the identification of clandestine graves. Four experiments using pigs as human decomposition analogues were performed over the course of 2011 and 2012 in southern Ontario to document changes in soil microbiology following decomposition. Studies were conducted in the spring and summer to document the effect of environmental conditions on the decomposition process and subsequent changes in gravesoil microbiology. Microbial activity was measured using a fluorescein diacetate assay as a preliminary indicator of changes within the soil microbial population. Both decreases and increases in microbial activity were observed throughout each decomposition experiment indicating that the microbial response to decomposition is complex. It is believed that environmental conditions and decomposition rates play a role in determining how taphonomic events affect soil microbial activity. Fatty acid methyl esters (FAME) profiling was used document community level changes throughout decomposition. Shifts in FAMEs profiles were brought on by the onset of active decay and persisted through to the dry remains stage. The fatty acids 3OH 12:0, 12:0, 16:0 and 18:0 were frequently found in higher amounts in gravesoils and may prove useful as markers of cadaver decomposition. Metagenomic profiles of soil microbial communities were obtained using Illumina?? sequencing. Decomposition was associated with changes v in microbial community composition. This allowed gravesoil samples to be differentiated from control samples for an extended period of time. Bacteria responsible for the shift in microbial profiles are those commonly associated with cadaver decomposition. Both sets of soil profiles indicated that weather had an effect on microbial community composition. Results highlight the need to document natural changes in microbial communities over seasons and years to establish normal microbial patterns to effectively use soil microbial profiles as post-mortem interval or clandestine grave indicators.
90

Using drilled-undrilled shell damage analysis to estimate crushing predation frequencies in modern marine gastropod assemblages

Stafford, Emily S. 06 1900 (has links)
Predation is a frequently studied subject, but estimating crushing predation in mollusk communities is challenging. Shells record successful attacks, but it is not always possible to identify attacks on an individual basis. Repair scar frequency is a common proxy for crushing mortality, but shell repair does not directly measure mortality, so results are ambiguous. Borrowing a technique from Vermeij (1982), crushing mortality frequencies were estimated in a recent shell assemblage. Because crushing damage can be confused with taphonomy, a taphonomic baseline was established: the cause of death of drilled shells is known, so additional damage is postmortem. The frequencies of several damage types were tallied for drilled shells to estimate a taphonomic baseline for the assemblage. The same frequencies were calculated for undrilled shells (cause of death unknown). In many cases, undrilled shells had significantly higher frequencies than drilled shells. The differences in damage frequencies likely are caused by crushing predation.

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