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Estratégia computacional para apoiar a reprodutibilidade e reuso de dados científicos baseado em metadados de proveniência. / Computational strategy to support the reproducibility and reuse of scientific data based on provenance metadata.Silva, Daniel Lins da 17 May 2017 (has links)
A ciência moderna, apoiada pela e-science, tem enfrentado desafios de lidar com o grande volume e variedade de dados, gerados principalmente pelos avanços tecnológicos nos processos de coleta e processamento dos dados científicos. Como consequência, houve também um aumento na complexidade dos processos de análise e experimentação. Estes processos atualmente envolvem múltiplas fontes de dados e diversas atividades realizadas por grupos de pesquisadores geograficamente distribuídos, que devem ser compreendidas, reutilizadas e reproduzíveis. No entanto, as iniciativas da comunidade científica que buscam disponibilizar ferramentas e conscientizar os pesquisadores a compartilharem seus dados e códigos-fonte, juntamente com as publicações científicas, são, em muitos casos, insuficientes para garantir a reprodutibilidade e o reuso das contribuições científicas. Esta pesquisa objetiva definir uma estratégia computacional para o apoio ao reuso e a reprodutibilidade dos dados científicos, por meio da gestão da proveniência dos dados durante o seu ciclo de vida. A estratégia proposta nesta pesquisa é apoiada em dois componentes principais, um perfil de aplicação, que define um modelo padronizado para a descrição da proveniência dos dados, e uma arquitetura computacional para a gestão dos metadados de proveniência, que permite a descrição, armazenamento e compartilhamento destes metadados em ambientes distribuídos e heterogêneos. Foi desenvolvido um protótipo funcional para a realização de dois estudos de caso que consideraram a gestão dos metadados de proveniência de experimentos de modelagem de distribuição de espécies. Estes estudos de caso possibilitaram a validação da estratégia computacional proposta na pesquisa, demonstrando o seu potencial no apoio à gestão de dados científicos. / Modern science, supported by e-science, has faced challenges in dealing with the large volume and variety of data generated primarily by technological advances in the processes of collecting and processing scientific data. Therefore, there was also an increase in the complexity of the analysis and experimentation processes. These processes currently involve multiple data sources and numerous activities performed by geographically distributed research groups, which must be understood, reused and reproducible. However, initiatives by the scientific community with the goal of developing tools and sensitize researchers to share their data and source codes related to their findings, along with scientific publications, are often insufficient to ensure the reproducibility and reuse of scientific results. This research aims to define a computational strategy to support the reuse and reproducibility of scientific data through data provenance management during its entire life cycle. Two principal components support our strategy in this research, an application profile that defines a standardized model for the description of provenance metadata, and a computational architecture for the management of the provenance metadata that enables the description, storage and sharing of these metadata in distributed and heterogeneous environments. We developed a functional prototype for the accomplishment of two case studies that considered the management of provenance metadata during the experiments of species distribution modeling. These case studies enabled the validation of the computational strategy proposed in the research, demonstrating the potential of this strategy in supporting the management of scientific data.
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Proveniência das rochas do Grupo Península Trinity, Antártica, como ferramenta para reconstrução da margem Pacífica do Gondwana / not availableHarabari, Andrea Prendalia 07 May 2014 (has links)
As rochas do Grupo Península Trinity e das unidadesequivalentes abrangem arenito, argilito e conglomerado, além de seus correspondentes metamórficos, e cuja formação é atribuída a correntes de turbidez. Afloram na parte norte da Península Antártica e arquipélagos adjacentes. Amostras de arenito, arcósio e conglomerado dessas unidades foram analisadas com intuito de traçar sua proveniência. A partir da análise petrográfica de arenito foi constatada a similaridade entre as rochas das formações do Grupo Península Trinity, Formação Grauvaca-Folhelho e Formação Miers Bluff. As rochas apresentam composição quartzo-feldspática, com baixa porcentagem de fragmentos líticos de composição plutônica, vulcânica e metamórfica. Diferenças composicionais ocorrem na Formação View Point, na qual também ocorre subarcóseo; e na Formação Miers Bluff, arcóseo lítico. As idades U-Pb de grãos detríticos de zircão para as rochas do Grupo Península Trinity da região de Botany Bay são concordantes e a mais jovem é 324 ± 8 Ma, ainda com quantidade expressiva de grãos com idades de 512 a 541Ma e 1001 a 1091Ma. Valores de ?Nd para rocha total, calculados para 220 Ma estão entre -5 e -8, indicando influência de fontes crustais recicladas ou de razoável residência crustal. A extensa gama de idades para a área-fonte indica reciclagem sedimentar de fonte diversa, com idades carboníferas, cambrianas e pré-cambrianas. O ?Hf calculado para as idades de U-Pb dos grãos de zircão detríticos mais jovens variade -1,2 a -5,7, também indicam extensa residência crustal. A amostra da Formação Legoupil, que complementa os dados de idades U-Pb em grãos detríticos de zircão para oGrupo Península Trinity, apresenta idade mais jovem de 265 ± 2, restringindo a idade máxima de sedimentação ao Permiano. Para as amostras da Formação Grauvaca-Folhelho as idades U-Pb em grãos detríticos de zircão apresentam duas concentrações bem definidas, permo-triássica e cambriana, com idade concordante mais jovem de 216 ± 2 Ma e mais antiga de 1,8 ± 0,13 Ga. Essas idades são condizentes com as dos grãos detríticos de zircão do Grupo Península Trinity. A partir dos dados de idades de grãos detríticos dezircão pode-se definir como a idade máxima para deposição para as formações Legoupil e Grauvaca-Folhelho sendo permo-triássica, assim como para as rochas do GrupoPenínsula Trinity em Botany Bay. Idades essas que levam a sugerir como fonte a Patagônia, no maciço Norte-patagônico, e Antártica Ocidental, na Terra de Mary Byrd. Estascondizem tanto em idade como em tipo de fonte, ígnea e metamórfica, com contribuição sedimentar. / The rocks of the Trinity Peninsula Group and equivalent units comprise sandstone, mudstone and conglomerate, as wel as their corresponding metamorphic rocks, whose formation is attributed to turbidity currents. They crop out in the northern Antarctic Peninsula and adjacent islands. Samples of sandstone, arkose and conglomerate of these units were analyzed in order to trace their provenance. From the petrographic analysis of sandstone was found similarity between the rocks of the Trinity Peninsula Group, Greywacke-Shale Formation and Miers Bluff Formation. The rocks have quartz-feldspathic composition, low percentage of lithic fragments of plutonic, volcanic and metamorphic rocks. Compositional differences occur in View Point Formation, which also occurs subarkose, and Miers Bluff Formation, lithic arcóseo. The U-Pb ages dates of detrital zircon grains in the rocks of the Trinity Peninsula Group region of Botany Bay are concordant and the youngest is 324 ± 8 Ma, but concentrations around 512-541Ma and 1001-1091Ma are common. Values of ?Nd calculated for 220 Ma are between -5 and -8, indicating influence of recycled crustal sources or with reasonable crustal residence. With extensive range of ages for the source area, indicating sediment recycling of diverse source areas, with ages spread from Carboniferous to Cambrian and Precambrian. The ?Hf calculated for dates U-Pb of younger detrital zircon ranges from -1.2 to -5.7, also indicate extensive crustal residence. The sample of Legoupil Formation, which complements the U-Pb dates for detrital zircon grains of the Trinity Peninsula Group, presents younger date of 265 ± 2, restricting the maximum age of the sedimentation asPermian. For samples of Greywacke-Shale Formation the U-Pb dates for detrital zircon grains exhibit two well-defined concentrations, permo-triassic and cambrian, with younger concordant date of 216 ± 2 Ma and older of 1.8 ± 0,13 Ga. These dates are consistent with those of detrital zircon grains from the Peninsula Group Trinity. From the data on detrital zircon grains can be defined as the maximum age for deposition for Legoupil and Greywacke-Shale formations being permo-triassic, as well as the rocks of the Trinity Peninsula Group in Botany Bay. Dates that suggest as a source area Patagonia, in Northern Patagonian massif and West Antarctica, in the Mary Byrd Land. These areas are consistent with both in age and rock types, igneous, metamorphic, and sedimentary, as the source area.
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Identification, caractérisation et mise en place des gisements d'obsidienne de quatre complexes volcaniques en Anatolie orientale, dans le cadre des études de provenance au Proche-Orient / Identification, characterization and emplacement of obsidian outcrops in four volcanic complex located in eastern Anatolia (Turkey) in the frame of obsidian sourcing in Near EastRobin, Anne-Kyria 27 October 2017 (has links)
Les études de provenance sur l’obsidienne se développent depuis 1964 quand ont été publiés les premiers travaux de Renfrew et Cann. Ces deux chercheurs ont démontré que chaque complexe volcanique possède une signature chimique propre permettant l’attribution d’artefacts archéologiques en obsidienne à un complexe volcanique présentant la même signature. Cette attribution fondée sur la géochimie permet d’envisager des routes de diffusion de l’obsidienne soulignant les contacts et les déplacements de populations préhistoriques. De nombreux sites archéologiques situés au Proche-Orient comportent en effet des assemblages lithiques présentant des artefacts en obsidienne. La synthèse dirigée par Cauvin et al., en 1998 suggère, pour le Proche-Orient, deux grandes régions d’approvisionnement en obsidienne : l’Anatolie centrale et l’Anatolie orientale. Or, pour des raisons liées à l’histoire intérieure de la Turquie dans les années 1980-1990, peu de données de terrain ont pu être rassemblées sur les sources d’Anatolie orientale jusqu’à ces toutes dernières années. Pourtant, les comparaisons entre affleurements repérés et prélevés avant les années 1980 montrent déjà clairement l’importance de la région pour les études de provenance d’artefacts collectés lors de fouilles de sites archéologiques en Anatolie orientale (ex : Çayönü, Körtik Tepe etc.), en Syrie (Tell Brak, Tell Zeidan, Khazna) et en Irak (Tell Arpachiyah, Tell Hamoukar, Um Dabaghiyah). Cette thèse, réalisée dans le cadre de l’ANR GeObs dirigée par D. Mouralis (Univ. Rouen, IDEES) en association avec C. Kuzucuoğlu (Univ. Paris 1, LGP) et L. Astruc (Univ. Paris 1, ArScan) et E. Akköprü (Univ. Van, Turquie), se concentre sur quatre régions volcaniques d’Anatolie orientale : le Meydan-Gürgürbaba, le Nemrut, et les massifs de dômes de Solhan et Alatepe. Ce travail de recherche a exploré : 1) l’identification et la caractérisation de plusieurs gisements (= « sources ») d’obsidienne, dont certains inconnus jusque-là ; 2) la discrimination de ces affleurements en fonction de leurs caractéristiques physiques et chimiques ; 3) la reconstitution de leur mode de mise en place lorsque cela a été rendu possible. Notre travail, basé sur l’importance incontournable de la connaissance experte du terrain, constitue une méthode novatrice dans les études de provenance. / Obsidian sourcing began in 1964 with studies by Renfrew and Cann. These authors demonstrated that one given volcano there is only one chemical signature. Based on this principle, it is possible to attribute one archaeological artefact to one volcano. This attribution allows then to develop studies on the contacts/exchanges/movements between prehistorical populations which are a key to understand past socio-cultural contexts from the Paleolithic to the Chalcolithic. Lithic assemblages in archaeological sites in the Near East contain indeed obsidian artefacts. As there is no volcano emplaced south of the Eastern Anatolian highlands, the nearest volcanic areas with obsidian outcrops that would attract near-eastern populations are located in Central and Eastern Anatolia (Cauvin et al., 1998). Taking advantage of the opening of Eastern Anatolia to field researches after 2000, and aiming at collecting scientific field data about obsidian sources in that region (especially on the volcano/outcrop scales geological and geomorphological contexts), the GéObs Project has obtained a 3 to 4 years ANR support for the study of the volcanic regions of Eastern Anatolia. Among these regions, four are concerned by our study: the Meydan-Gürgürbaba, Nemrut, Solhan and Alatepe regions. The ANR project GéObs, led by D. Mouralis (Rouen Univ./IDEES), associated with C. Kuzucuoglu (Paris 1 Univ./LGP) and L. Astruc (Paris 1 Univ./ArScan) enhances: 1) the identification of obsidian outcrops (some of which had not yet been identified), 2) the discrimination of these outcrops according to their characteristics (accessibility and types), 3) the characterization of obsidian glass (micro facies; geochemistry; mineralogy), and consecutive reconstruction of their emplacement modes. This research, based on the necessary completeness of data collection in the field, demonstrates the importance of such a new approach in the domain of “obsidian sourcing” researches.
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Estratégia computacional para apoiar a reprodutibilidade e reuso de dados científicos baseado em metadados de proveniência. / Computational strategy to support the reproducibility and reuse of scientific data based on provenance metadata.Daniel Lins da Silva 17 May 2017 (has links)
A ciência moderna, apoiada pela e-science, tem enfrentado desafios de lidar com o grande volume e variedade de dados, gerados principalmente pelos avanços tecnológicos nos processos de coleta e processamento dos dados científicos. Como consequência, houve também um aumento na complexidade dos processos de análise e experimentação. Estes processos atualmente envolvem múltiplas fontes de dados e diversas atividades realizadas por grupos de pesquisadores geograficamente distribuídos, que devem ser compreendidas, reutilizadas e reproduzíveis. No entanto, as iniciativas da comunidade científica que buscam disponibilizar ferramentas e conscientizar os pesquisadores a compartilharem seus dados e códigos-fonte, juntamente com as publicações científicas, são, em muitos casos, insuficientes para garantir a reprodutibilidade e o reuso das contribuições científicas. Esta pesquisa objetiva definir uma estratégia computacional para o apoio ao reuso e a reprodutibilidade dos dados científicos, por meio da gestão da proveniência dos dados durante o seu ciclo de vida. A estratégia proposta nesta pesquisa é apoiada em dois componentes principais, um perfil de aplicação, que define um modelo padronizado para a descrição da proveniência dos dados, e uma arquitetura computacional para a gestão dos metadados de proveniência, que permite a descrição, armazenamento e compartilhamento destes metadados em ambientes distribuídos e heterogêneos. Foi desenvolvido um protótipo funcional para a realização de dois estudos de caso que consideraram a gestão dos metadados de proveniência de experimentos de modelagem de distribuição de espécies. Estes estudos de caso possibilitaram a validação da estratégia computacional proposta na pesquisa, demonstrando o seu potencial no apoio à gestão de dados científicos. / Modern science, supported by e-science, has faced challenges in dealing with the large volume and variety of data generated primarily by technological advances in the processes of collecting and processing scientific data. Therefore, there was also an increase in the complexity of the analysis and experimentation processes. These processes currently involve multiple data sources and numerous activities performed by geographically distributed research groups, which must be understood, reused and reproducible. However, initiatives by the scientific community with the goal of developing tools and sensitize researchers to share their data and source codes related to their findings, along with scientific publications, are often insufficient to ensure the reproducibility and reuse of scientific results. This research aims to define a computational strategy to support the reuse and reproducibility of scientific data through data provenance management during its entire life cycle. Two principal components support our strategy in this research, an application profile that defines a standardized model for the description of provenance metadata, and a computational architecture for the management of the provenance metadata that enables the description, storage and sharing of these metadata in distributed and heterogeneous environments. We developed a functional prototype for the accomplishment of two case studies that considered the management of provenance metadata during the experiments of species distribution modeling. These case studies enabled the validation of the computational strategy proposed in the research, demonstrating the potential of this strategy in supporting the management of scientific data.
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Provenance-based computingCarata, Lucian January 2019 (has links)
Relying on computing systems that become increasingly complex is difficult: with many factors potentially affecting the result of a computation or its properties, understanding where problems appear and fixing them is a challenging proposition. Typically, the process of finding solutions is driven by trial and error or by experience-based insights. In this dissertation, I examine the idea of using provenance metadata (the set of elements that have contributed to the existence of a piece of data, together with their relationships) instead. I show that considering provenance a primitive of computation enables the exploration of system behaviour, targeting both retrospective analysis (root cause analysis, performance tuning) and hypothetical scenarios (what-if questions). In this context, provenance can be used as part of feedback loops, with a double purpose: building software that is able to adapt for meeting certain quality and performance targets (semi-automated tuning) and enabling human operators to exert high-level runtime control with limited previous knowledge of a system's internal architecture. My contributions towards this goal are threefold: providing low-level mechanisms for meaningful provenance collection considering OS-level resource multiplexing, proving that such provenance data can be used in inferences about application behaviour and generalising this to a set of primitives necessary for fine-grained provenance disclosure in a wider context. To derive such primitives in a bottom-up manner, I first present Resourceful, a framework that enables capturing OS-level measurements in the context of application activities. It is the contextualisation that allows tying the measurements to provenance in a meaningful way, and I look at a number of use-cases in understanding application performance. This also provides a good setup for evaluating the impact and overheads of fine-grained provenance collection. I then show that the collected data enables new ways of understanding performance variation by attributing it to specific components within a system. The resulting set of tools, Soroban, gives developers and operation engineers a principled way of examining the impact of various configuration, OS and virtualization parameters on application behaviour. Finally, I consider how this supports the idea that provenance should be disclosed at application level and discuss why such disclosure is necessary for enabling the use of collected metadata efficiently and at a granularity which is meaningful in relation to application semantics.
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Late Palaeozoic to Early Mesozoic evolution of the Palaeotethys in Turkey: Insights from the Karaburun Peninsula and the Konya ComplexLöwen, Kersten 15 November 2018 (has links)
No description available.
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High-resolution sequence stratigraphy and detrital zircon provenance of the Ordovician Ancell Group in the Iowa and Illinois Basins: insight into the evolution of midcontinental intracratonic basins of North AmericaIbrahim, Diar Mohammed 01 May 2016 (has links)
The Middle Ordovician Ancell Group, including the St. Peter Sandstone, Glenwood Shale and Starved Rock Formation, records intracontinental basin development during eustatic sea level changes in Iowa and Illinois. The St. Peter Sandstone overlies the Prairie du Chien Group across an erosional unconformity that marks a major sequence boundary, whereas upper contact of the St. Peter Sandstone with the Glenwood Shale also is a second sequence boundary. Data from 80 wells, selected well logs, and 20 cores were integrated to refine the high-resolution sequence stratigraphy of the Ancell Group. Two main sequences bounded by three sequence boundaries are interpreted to represent 3rd order sequences. Distinctive shallowing-upward parasequences bounded by flooding surfaces in many cores record higher frequency relative sea level fluctuations in the Ancell Group, but these cannot presently be correlated regionally. Facies variations define an aggradational transgressive systems tract TST), a prograding highstand systems tract (HST) and down stepping falling stage system tract (FSST) in both the St. Peter Sandstone and the Glenwood Shale-Starved Rock Formation units. The St. Peter Sandstone thickens towards the northeast and thins to the northwest and southwest in Iowa. In contrast, the St. Peter Sandstone in Illinois thickens to the south likely recording a prolonged FSST incised valley or channel fill. Detrital zircon geochronology of 13 samples from the St. Peter Sandstone and Starved Rock Formation define common peaks at 1100-1500 Ma and 2500-2700 Ma with minor components at 1670-1750 Ma and 3000-3600 Ma. The detrital zircon signature is dominated by Archean, and Grenville (1000-1300 Ma) ages. The detrital zircon geochronology indicates that the Ancell Group was sourced directly from the Archean Superior Province to the north and Grenville Province to the northeast, although recycling of Archean grains from the Paleoproterozoic Huron Basin cannot be ruled out. The near complete lack of 1800-1900 Ma ages argues against derivation of detritus from the Trans-Hudson or Penokean Orogens. The Transcontinental Arch northwest of the Iowa Basin acted as a barrier to sediment transport from the Trans-Hudson Orogen. Basement rocks of the Penokean Orogen are inferred to have been covered by water or younger sediments southeast of the Iowa Basin. CIA analyses of Ordovician shale samples from around the Transcontinental Arch indicate that the climate condition during Middle Ordovician time was warm and humid. This is consistent with a paleoclimate interpretation where mechanical erosion and chemical weathering yielded first cycle mature quartz arenites (Witzke, 1980).
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TESTING FOR SEDIMENTARY RECYCLING USING DETRITAL MONAZITE GEOCHRONOLOGY, ZIRCON “DOUBLE DATING”, AND TEXTURES IN PENNSYLVANIAN ARENITES OF THE CENTRAL APPALACHIAN BASIN, EASTERN KENTUCKY: IMPLICATIONS FOR SINGLE MINERAL SEDIMENTARY PROVENANCE ANALYSISZotto, Steve C. 01 January 2019 (has links)
Detrital monazite Th-Pb and detrital zircon U-Pb and U-Th/He double-dating coupled with sandstone petrography and exhumation rates can be used to test for sediment recycling in Pennsylvanian sandstones within the Alleghenian clastic wedge. The Alleghenian clastic wedge is a logical system in which to test for sediment recycling as four major collisional events (Grenville, Taconic, Acadian and Alleghenian orogenies) likely reworked the continental margin and recycled siliciclastic sediment. The combination of these geochronologic and thermochronologic methods provide a more accurate assessment of the proportion of recycled sediment in the Grundy Formation (sublitharenite) and the Corbin Sandstone (quartz arenite), which past studies and the use of standard zircon U-Pb alone could not distinguish. Recognition of sediment recycling is thus critical for sedimentary provenance studies, which assume a direct path from sediment source to depositional basin. Zircon U-Pb age modes for both formations include the dominant “Grenville doublet” along with a lesser component of Granite-Rhyolite and Taconic age modes. The Corbin Sandstone is temporally more expansive, with age modes associated with the Yavapai-Mazatzal and Kenoran orogenies not present in the Grundy Formation. Monazite Th-Pb age modes are younger than zircon U-Pb for both samples, with dominant modes in the Taconic, Acadian, and Alleghenian, and only minor age modes associated with the Grenville Orogeny. The extent of sediment recycling was quantified by the difference in crystallization ages and exhumation/cooling ages of detrital zircon. This difference in time (∆t) becomes higher in the case of recycling (> ~300 Ma). A median 288 Ma ∆t cutoff value between first-cycle and multi-cycle Grenville aged zircons was calculated using post-Grenville exhumation rates. Furthermore, “detrital diagenetic monazite” grains older than the 312 Ma age of deposition are present in both the Grundy Formation and Corbin Sandstone and proves the occurrence of sediment recycling. In conclusion, most detrital grains of Grenville origin and older are likely multi-cycle, while detrital grains associated with the Taconic, Acadian, Neo-Acadian, and Alleghenian orogenies are likely first-cycle in origin.
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Provenance response to flat-slab subduction as recorded in detrital zircon signatures from the southern Alaskan forearc basin systemHedeen, Tyler 01 May 2016 (has links)
Strata in the Cook Inlet forearc basin in south-central Alaska record the effects of tectonic events related to normal subduction and two flat-slab subduction events. Through detrital zircon geochronology we track provenance changes of strata deposited in a forearc basin in conjunction with these different subduction processes. Our data from strata deposited concurrent with normal subduction help to confirm previous provenance models of forearc basins that suggest provenance is sourced primarily from a proximal, coeval arc. However, compared to these models, our data from strata deposited coincident to flat-slab events show markedly different provenance signatures dependent upon: (1) geographic position relative to the flat-slab event; (2) pre-established, or lack thereof, topography; and (3) type of flat-slab event. Detrital zircon signatures of strata deposited in the Cook Inlet after flat-slab subduction of a mid-ocean ridge diversify to include older detritus found in the distal inboard region. This distal signature is then incrementally cut-off in younger strata due to deformation of the upper-plate from progressive insertion of a shallowly subducted oceanic plateau. Detrital zircon signatures for strata associated with each flat-slab event are largely older than depositional age due to the lack of coeval arc activity. Our data may help to improve the ability to recognize other flat-slab events through detrital zircon geochronology. In particular, changes in detrital zircon signatures found in strata deposited during flat-slab subduction of an oceanic plateau correlate well with the exhumation of rocks associated with the propagation of deformation in the over-riding plate due to plate coupling.
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Insights for provenance analysis of modern watersheds from detrital apatite and detrital zircon U-PB geochronology- Talkeetna Mountains, southcentral AlaskaAmes, Carsyn Jean 01 May 2018 (has links)
Detrital zircon U-Pb geochronology is a useful tool for analyzing provenance in the sedimentary record. Differentiating recycled and first cycle populations in the detrital record, however, is not a straightforward process. A second potential problem in using detrital signatures to determine provenance of sediment lies in the assumption that detrital signatures of modern rivers reflect input from each exposed unit in the catchment boundaries. To investigate each of these problems, I present U-Pb analysis of detrital zircon (DZ) from modern river sand collected from 20 watersheds, 6 detrital apatite (DA) signatures from modern river sand, and 6 DA signatures from exposed strata, all within the Talkeetna Mountains (south-central Alaska). DA rarely survives past the first cycle of erosion and deposition due to its inability to survive chemical weathering, and thus dominantly represent igneous input in detrital signatures, whereas zircon can be of igneous origin or can survive multiple cycles of erosion and deposition. By comparing the DA signatures with the DZ signatures, I present a method to better differentiate first cycle, igneous sediment contributions from recycled populations within a detrital signature. The results of these comparisons show that DA signatures provide ages of igneous input into the detrital record; these ages are also reflected in the DZ signature, thus signaling these DZ populations as igneous in origin. This study also investigates the potential for DA recycling and DA input from recycled strata. To address the second problem, I present a method using GIS software and the most recent map of Alaska to create simulated signatures that records input on a scale proportionate to the exposed surface area of each bedrock unit. In ~35% of the watersheds tested, the simulated signatures predict trends similar to the DZ signatures from the modern river sands, in 55% of the watersheds tested the simulated signatures missed one or more populations present in the DZ signature, and in 10% of watersheds tested, the simulated signature predicted trends very different from the DZ signatures. In cases where the DZ and simulated signatures do not match, I believe this represents influences of climate and relief and zircon fertility.
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