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A Sequence Stratigraphic Approach To The Depositional History Analysis Of The Upper Eocene Sedimentary Succession, Northwest Of The Thrace Basin, TurkeySunnetcioglu, Mehmet Akif 01 February 2008 (has links) (PDF)
This study investigates the depositional history of the Late Eocene sedimentary record in the northwest of the Thrace Basin in a sequence stratigraphic approach and estimates the contribution of regional tectonics, basin physiography and eustasy. Late Eocene sedimentary succession was analyzed in two third-order sequences based on two major data sets / seismic reflection and well data sets. Depositional Sequence-1, represented by progradational stacking patterns, comprises the coarse-grained Hamitabat turbidite system. The base of the Sequence-1 was defined as the base of channel fill deposits in the northern shelf setting and the base of slope fan deposits in the slope setting. This boundary separates Lower-Middle and Upper Eocene sediments. In the slope setting, the Hamitabat turbidite system was analyzed in three major depocenters / Western, Northwestern and Northeastern depocenters respectively.
Hamitabat turbidite system was controlled by the interaction of regional tectonics, basin physiography and eustatic fluctuations in the Late Eocene. This study highlighted the role of the regional variables / tectonic
influence and basin morphology on the submarine canyon formation. The facies distribution was controlled by the high subsidence rate of sea-floor dominantly instead of eustasy.
Depositional Sequence-2, represented by mostly retrogradational stacking patterns, is a clastic-carbonate mixed system. Depositional Sequence-2 was subdivided into three higher-order sequences. The lower sequence boundaries were induced by the rapid relative sea-level rise. The
upper boundary of the Depositional Sequence-2 was defined as the termination of clastic-carbonate mixed system and a candidate for the Eocene-Oligocene contact.
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Depositional dynamics in a mixed carbonate–siliciclastic system, trilobite fauna, biostratigraphy and biofacies: middle–upper Cambrian Abrigo Formation, southeastern Arizona.2015 June 1900 (has links)
The mixed carbonate–siliciclastic Abrigo Formation of middle and late Cambrian age, which crops out in southeastern Arizona, was deposited during the Sauk transgression in the craton interior, landward of the passive margin of Laurentia. The Abrigo Formation consists of ten basic rock types: claystone, siltstone, sandstone, lime mudstone, wackestone, bioclastic grainstone, packstone, oolitic packstone, oncolitic packstone, and intraclastic conglomerate. These comprise fifteen lithofacies, which are grouped into eight facies associations. They represent an array of shallow-marine environments that were dominated by wave and storm activity. The interpreted paleoenvironments include lower offshore, upper offshore, offshore transition, and lower, middle and upper shoreface. One hundred eighty-two collections, yielding 940 trilobite remains have been found in the Abrigo Formation. They represent 69 species and 42 genera. Eight of the species are new. The fossil age ranges from early Marjuman to late Steptoean. Eight trilobite biofacies are defined from the generic relative abundance data: Ehmaniella, Olenoides–Bolaspidella, Blairella, Eldoradia, Modocia–Paracedaria, Cedaria, Coosella–Coosina, and Camaraspis. Trilobites collected and identified in this study are assigned to five biostratigraphic zones: Bolaspidella, Cedaria, Crepicephalus, Aphelaspis, and Elvinia zones. In addition, two subzones had been defined. Cedaria eurycheilos Subzone recognized in the upper part of Cedaria Zone and Coosella helena Subzone recognized in the upper part of Crepicephalus Zone.
The stratigraphic succession was divided into six distinct phases associated with large-scale relative sea-level fluctuations. An initial flooding over the Bolsa Quartzite forming the transgressive systems tract was terminated by maximum flooding, and a subsequent highstand systems tract developed during Bolaspidella Biozone time. The second sequence starts with another transgressive systems tract, and is overlain by a final highstand systems tract during the Cedaria and Crepicephalus biozones. The uppermost part of the second sequence represents a falling stage systems tract that developed during Aphelaspis Biozone time. The presence of Elvinia Biozone trilobites near the base of the highest sandstone unit suggests that delivery and deposition of these sands took place during the lowstand that followed the protracted and widespread Sauk II–Sauk III hiatus. Sedimentary dynamics were controlled by storm-induced wave action and offshore flows. There are two carbonate factories that operated simultaneously in this Cambrian inner shelf region. Dominance of carbonate versus siliciclastic strata in the offshore transition setting is interpreted to reflect periods when siliciclastic input was depleted, such that increasing accommodation and reduction of clay and possibly nutrients promoted carbonate production. Clay and silt bypassed the nearshore carbonate-depositing zone. Siliciclastic sediment input and dispersal were not only restricted to the falls in sea level, but appear to have dominated the transgressive systems tract and late phase of the highstand. Thus, carbonate sedimentation does not dominate the entire highstand systems tract as is commonly held but, rather, only during the late phase of the transgressive and early highstand phase. The comparison of this Cambrian model with younger mixed carbonate-siliciclastic units will help reveal the subtleties of the carbonate factory and how it operated in response to biotic evolution.
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Estrutura genética e sistema de cruzamento em Eugenia dysenterica DC. (Mvrtaceae) / Genetic structure and mating system in Eugenia dysenterica DC. (Myrtaceae)Barbosa, Ana Clara de Oliveira Ferraz 28 March 2014 (has links)
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Previous issue date: 2014-03-28 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Fundação de Amparo à Pesquisa do Estado de Goiás - FAPEG / The genetic structure of a species corresponds to the amount of genetic
variability and its distribution within and among local populations and individuals. The
patterns of variability among individuals in a local population are highly dependent of
mating system. The goal of this study was to evaluate the mating system, the diversity
and genetic structure in populations of E. dysenterica in local and regional scale. The
assessment of the mating system and the analysis of genetic structure at the local scale
were performed in a population of Mimoso – GO and for the analysis of genetic
structure at the regional scale were analyzed 23 natural populations of E. dysenterica
derived from six Brazilian states (Goiás, Minas Gerais, Bahia, Mato Grosso, Tocantins
and Piauí). For all studies seven polymorphic microsatellite loci were used. Considering
the 20 families analyzed, the multilocus outcrossing rates (tm = 0.918) and single locus
(ts = 0.797) were high and significant. From a total of 399 seeds evaluated, it was
possible to determine the pollen donor to 218 seeds (55%) with confidence level of
90%, 174 seeds (44%) with confidence level of 95% and 65 seeds (16%) with
confidence level of 99%. In 15 families evaluated were possible to verify the occurrence
of multiple paternity, with the number of pollen donor per fruit ranged from one to
three. The results presented show that the species E. dysenterica presents mixed mating
system and that there is multiple paternity in this species. The intrapopulational spatial
genetic structure was positive (R2 = 0.01646, p < 0.001), which was expected since
species generally have spatial restriction to disperse. The spatial genetic structure was
significant (Sp = 0.0143) and genetic neighborhood (Nb) was equal to 69.93 km. On
average, about 30 individuals were analyzed by subpopulation for all loci. The average
number of alleles per locus was equal to 9, the genetic diversity was high (0.725) and
the observed frequency of heterozygotes (Ho) was 0.610. Were found 18 private alleles
in 10 subpopulations. The results for the fixation index ((f) in the subpopulations ranged
between -0.058 and 0.338, with an overall value of 0.162, indicating excess of
homozygotes in relation to the expected under HWE. The genetic differentiation
between subpopulations can be considered relatively high (FST = 0.161). The Mantel test
indicates that the genetic divergence of 24 subpopulations evaluated is structured in
geographic space (r = 0.427, p < 0.001), suggesting that the model of isolation by
distance or stepping-stone are adequate to explain the spatial pattern of genetic
divergence among subpopulations of E. dysenterica evaluated. / A estrutura genética de uma espécie corresponde à quantidade da
variabilidade genética e sua distribuição dentro e entre populações locais e indivíduos.
Os padrões de variabilidade entre indivíduos em uma população local são altamente
dependentes do sistema de cruzamento. O objetivo geral do trabalho foi avaliar o
sistema de cruzamento, a diversidade e a estrutura genética em populações de E.
dysenterica, em escala local e regional. A avaliação do sistema de cruzamento e a
análise da estrutura genética intrapopulacional foram realizadas em uma população do
município de Mimoso – GO e para a estrutura genética interpopulacional foram
analisadas 23 subpopulações naturais de E. dysenterica oriundas de seis estados
brasileiros. Para todos os estudos foram utilizados sete locos microssatélites
polimórficos. Considerando as 20 famílias analisadas, as taxas de fecundação cruzada
multiloco (tm = 0,918) e uniloco (ts = 0,797) foram altas. De um total de 399 sementes
avaliadas, foi possível determinar o doador de pólen para 218 sementes (55%) com
confiança de 90%, 174 sementes (44%) com confiança de 95% e 65 sementes (16%)
com confiança de 99%. Em 15 famílias avaliadas foi possível verificar a ocorrência de
paternidade múltipla, sendo que o número de doador de pólen por fruto variou de um a
três. Os resultados apresentados revelam que a espécie E. dysenterica apresenta sistema
de cruzamento misto e que existe paternidade múltipla nessa espécie. A estrutura
genética espacial intrapopulacional foi positiva (R2 = 0,01646, p < 0,001), o que era
esperado, uma vez que espécies vegetais geralmente possuem restrição espacial para se
dispersarem. A estrutura genética espacial foi significativa (Sp = 0,0143) e a vizinhança
genética (Nb) foi igual a 69,93 km. Em média, foram analisados aproximadamente 30
indivíduos por subpopulação para todos os locos. O número médio de alelos por loco foi
igual a 9, a diversidade genética foi alta (0,725) e a frequência observada de
heterozigotos (Ho) foi 0,610. Foram encontrados 18 alelos privados em 10
subpopulações. Os resultados obtidos para o índice de fixação (f) variaram nas
subpopulações entre -0,058 e 0,338, com valor global igual a 0,162, indicando excesso
de homozigotos em relação às frequências esperadas sob EHW. A diferenciação
genética entre as subpopulações pode ser considerada relativamente alta ( P = 0,161). O
teste de Mantel indica que a divergência genética das 23 subpopulações avaliadas está
estruturada no espaço geográfico (r = 0,427; p < 0,001), sugerindo que o modelo de
isolamento-por-distância ou stepping-stone são adequados para explicar o padrão
espacial de divergência genética entre as subpopulações de E. dysenterica avaliadas.
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[en] SEMI-RIGID COMPOSITE SYSTEMS FOR RESIDENTIAL BUILDINGS / [pt] DESENVOLVIMENTO DE SISTEMAS ESTRUTURAIS SEMI-RÍGIDOS EM AÇO E MISTOS PARA EDIFICAÇÕES RESIDENCIAIS MULTI-FAMILIARESOLAVO FERREIRA BRITO JUNIOR 26 December 2001 (has links)
[pt] O dimensionamento de estruturas de edifícios de aço com
ligações do tipo semi-rígidas ainda enfrenta uma série de
resistências por parte dos engenheiros estruturais. Este
fato se deve em parte à falta de normas específicas,
programas de computadores adequados e informações mais
detalhadas sobre as vantagens econômicas das ligações semi-
rígidas. Este trabalho apresenta um estudo paramétrico de
uma edificação considerando o dimensionamento das ligações
no regime semi-rígido. Estas investigações consideram
parâmetros como: a rigidez das ligações, sistemas com
estruturas em aço ou mistos e estabilidade lateral dos
pórticos. A edificação analisada foi uma habitação popular
padronizada de quatro pavimentos desenvolvida pela
USIMINAS, muito difundida no Brasil. Em uma primeira etapa
cada edifício foi estudado com uma rigidez de ligação semi-
rígida padrão para todas as ligações da estrutura.
Posteriormente ligações semi-rígida individualizadas foram
adotadas para os diversos pórticos estudados. Este trabalho
a princípio apresenta uma metodologia de análise e
dimensionamento de estruturas em aço com ligações semi-
rígidas com base no modelo de molas proposto pelo Anexo J
Revisado do Eurocode 3. Com base nesta metodologia propõe-
se um modelo simplificado de ligações semi-rígidas
viga/coluna com o uso do programa ANSYS. Os modelos
estruturais foram estudados com a inclusão dos efeitos da
não linearidade geométrica dos pórticos e o comportamento
elasto-plástico do material de forma a se obter resultados
consistentes com os resultados experimentais e sem a
introdução de coeficientes de correção. Os resultados
obtidos neste trabalho foram apresentados, discutidos e
comparados com os desenvolvidos pela USIMINAS de forma a se
analisar o comportamento das ligações e sua eficiência.
Para os edifícios considerados neste trabalho, onde se fez
uso de ligações semi-rígidas padrão, o sistema mais
econômico, com relação à peso de aço, foi a
estrutura mista com contraventamentos (40 por cento da capacidade
rígida) que teve uma economia de até 48 por cento em relação aos
outros edifícios e de até 10 por cento aos sistemas da USIMINAS.
Quando no uso de ligações otimizadas estas economias
aumentam para 53 por cento e 15 por cento. Os resultados apresentados
confirmam a vantagem da utilização deste tipo de ligação em
edifícios residenciais em aço de pequena altura. / [en] Nowadays, despite the substantial increase in structural
design knowledge, the semi-rigid connections steel design
is still facing resistance from the structural engineers.
This fact can be in part explained by few design standards
that allows and explains their use, suitable computer
programs and the lack of detailed information of
the economical advantages of the semi-rigid design
philosophy. This work presents a parametric analysis
performed on a residential low-rise steel building
considering all the steps necessary to a semi-rigid design.
This analysis considered parameters like: beam-to-column
connection stiffness and strength,structural system (steel
or composite) and lateral frame stability (sway and non-sway
frame solutions). The analysed structure consisted on a
standard four pavements residential building proposed by a
Brazilian Steel Mill Usiminas for low-cost popular
constructions. Initially all the structure beam-to-column
connections adopted a standard connection stiffness. The
study continued with optimised connection stiffness for
each of the designed structural frames. The first part of
the present work is devoted to a full description of the
design procedures proposed in the Eurocode 3, revised annex
J for semi-rigid connection design. Based on this
methodology a simple design model was proposed and
implemented with the aid of the finite element program
Ansys. The model included geometrical and material non-
linearities and considered the connections semi-rigid
behaviour avoiding the conventional approximations
suggested in several current steel design standards.
The results of this investigations are presented, discussed
and compared to standard designs like the Usiminas proposal
as means to access the economic potential and efficiency of
the semi-rigid solutions. The best structural solution for
the investigated construction was a non-sway composite semi-
rigid (40 percent of the rigid capacity). The economy achieved
were: 48 percent and 10 percent when compared to other semi-rigid
solutions and the conventional Usiminas solution,
respectively. This figures changed to 53 percent and 15 percent when
optimised connections were used in each structural
frame. The presented results confirm the advantage of the
use of this connections kind in residential buildings in
steel of low height.
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[en] ANALYSIS OF THE INTERACTION EFECT BETWEEN STEEL AND CONCRETE ON THE DYNAMICAL RESPONSE OF COMPOSITE FLOORS / [pt] ANÁLISE DO EFEITO DA INTERAÇÃO AÇO-CONCRETO SOBRE A RESPOSTA DINÂMICA DE PISOS MISTOSANTONIO VICENTE DE ALMEIDA MELLO 28 July 2010 (has links)
[pt] Ao longo dos anos, a interação aço-concreto tem obtido um lugar de
destaque do ponto de vista estrutural, ampliando a gama de soluções em concreto
armado e aço, o que permite atender aos novos desafios arquitetônicos e às
exigências que o mercado impõe. O objetivo do sistema misto é a combinação
desses dois materiais, formando um único sistema estrutural em que a capacidade
portante de cada elemento possa ser explorada ao máximo, tirando-se proveito da
grande capacidade do concreto resistir a esforços de compressão, e de o aço, à
tração. Essas características singulares de sistemas mistos aço-concreto conduzem
a frequências naturais mais próximas da faixa de frequência de excitações
associada às atividades humanas. Sendo assim, as considerações relacionadas ao
projeto estrutural obrigam os engenheiros a fazer verificações quanto à resistência
e à estabilidade de sistemas estruturais (estados limites últimos), mas os
problemas relacionados ao estado limite de utilização desses sistemas devem ser
analisados de forma mais cuidadosa. Embora o assunto de vibrações em lajes de
edifícios induzidas por atividades humanas tem sido de continuado interesse a
pesquisadores e a engenheiros ao longo dos últimos dois séculos (1828-2009),
inexiste na literatura técnica, até onde o autor tem conhecimento, análise de
correlações teórico-experimentais de vibrações de estruturas mistas aço-concreto
sob ação de atividades humanas, na qual são consideradas a ortotropia, a interação
parcial e as ligações semirrígidas. Com o objetivo de contribuir nessa direção, o
presente trabalho investiga o efeito da interação aço-concreto sobre a resposta
dinâmica de sistemas de pisos mistos. / [en] Over the years the steel-concrete interaction have been achieving excelent
results, in terms of structural performance. This fact have enlarged the range of
applications of concrete and steel structures enabling the development of efficient
solutions that attend the demands claimed by the market and by increasinly daring
architectures. The composite action main objective is to combine steel and
concrete into single structural system where the optimum performance of the
combined elements could be explored. The concrete is used to sustain
compressive while the steel is better used when submitted to tension. These
singular characteristics of the composite systems, on the other hand, lead to
composite structural systems with natural frequencies close to the frequency
associated to human induced loads. Usually the design of composite structures is
focused on verifications related to ultimate limit states associated to strength and
stability, but the problems related to serviceability limit states should also be
carefully considered. Despite the fact that floor vibration induced by human
activity has been extensively investigated in the past (1828-2009) there is still a
lack of published information on theoretical-experimental correlations on the
dynamic response of composite structures specially after considering effects
releted to partial interaction, orthotropy and semi-rigid connections. The present
study has the objective of contributing in the direction of better understand the
effect of the steel-concrete interaction on the composite floor system dynamic
response.
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Les relations entre diapirisme et sédimentation : exemple du Jurassique moyen de la région d'Imilchil, Haut-Atlas central, Maroc / Relationships between diapirism and sedimentation : Middle Jurassic of the Imilchil area, Central High-Atlas, MoroccoJoussiaume, Rémi 09 September 2016 (has links)
Le Haut-Atlas central est un bassin salifère structuré autour d’étroites rides diapiriques (i.e. salt walls) orientées ENE-OSO qui bordent de larges mini-bassins. L’impact de la compression cénozoïque étant relativement limitée, les structures diapiriques y sont particulièrement bien préservées. L’objectif de la thèse est d’analyser les relations entre la sédimentation et la croissance des rides diapiriques dans le cadre imposé par l’évolution du système sédimentaire, durant le Jurassique inférieur et moyen, dans la région d’Imilchil, au cœur du haut-Atlas central. Le Lias-Dogger enregistre le comblement du bassin atlasique à travers six séquences de transgression-régression de troisième ordre. Cette grande tendance régressive se manifeste par la succession de trois systèmes de dépôts. Un système carbonaté, du Toarcien au Bajocien supérieur, dont l’éventail de faciès oscille entre la rampe moyenne et la rampe externe distale. Au Bajocien supérieur l’apport de sédiments terrigènes dans le bassin provoque la disparition du système carbonaté qui est recouvert par une épaisse série sédimentaire mixte peu profonde. Ce système mixte perdure jusqu’au Bathonien inférieur puis il est progressivement remplacé par un système fluviatile silico-clastique. Les relations entre les mouvements diapiriques et la sédimentation peuvent être mises en évidence par une modification de la géométrie des dépôts, par des variations de faciès aux abords des diapirs, et/ou par des événements sédimentaires particuliers (surfaces d’érosion, brèches, niveau condensé). L’analyse de ces interactions en fonction des séquences de transgression-régression permet de définir une chronologie de l’activité diapirique. Elle est continue pendant le Jurassique inférieur et moyen mais connait une évolution polyphasée comprenant deux périodes d’activité majeure, du Toarcien à l’Aalénien terminal et du Bajocien supérieur jusqu’à ce que les diapirs soient scellés au Bathonien supérieur-Callovien inférieur. Ces deux périodes encadrent un épisode de plus faible intensité pendant la progradation et le développement de la rampe carbonatée bajocienne. Les interactions entre diapirisme et sédimentation sont synthétisées dans un modèle empirique à travers quatre types de prismes de dépôts, définis selon des critères géométriques et sédimentologiques, et qui rendent compte de la configuration du système sédimentaire, ainsi que de la position du diapir et de sa couverture au moment du dépôt : A plus grande échelle l’influence du développement des mini-bassins sur la sédimentation s’exprime par une distribution préférentielle des faciès sédimentaire dans les systèmes de dépôt carbonaté et mixte. Les faciès proximaux, et en particulier les faciès granulaires de haute énergie, se regroupent autour des rides diapiriques tandis que les faciès distaux de basse énergie se concentrent dans l’axe des mini-bassins. / The High-Atlas salt basin is formed by a set of ENE-WSW-trending and 15-to-80-kilometers-long narrow diapiric ridges (i.e. salt walls) bounding large mini-basins mildly deformed during Cenozoic shortening. The aim of this thesis is to analyze the relationships between sedimentation and diapiric growth during the Lower and Middle Jurassic in the Imilchil region (Central High-Atlas). In this area, the Lias and Dogger series form a large regressive trend composed by six third-order transgression-regression (T/R) sequences and characterized by the succession of three sedimentary systems. A carbonate system develop from Toarcian to Upper Bajocian, with a facies range from middle ramp to distal outer ramp. From Upper Bajocian, a terrigenous supply in the basin causes the end of the carbonate system and leads to the deposition of a thick shallow mixed unit. From Lower Bathonian, this mixed sedimentary system is gradually replaced by an alluvial silici-clastic system. Relationships between diapiric movements and sedimentation are interpreted from depositional geometries, facies variations in the vicinity of diapirs and/or particular sedimentary events (erosional surfaces, breccia, condensed levels). The analysis of these interactions, based on T/R sequences, enables to define a chronology of the diapiric activity in the Imilchil area. The activity is continuous during the Lower and Middle Jurassic but shows a non-linear development with two phases of high-intensity, one from Toarcian to Uppermost Aalenian, and one from Upper Bajocian. These two phases surround a period of low-intensity during the progradation and the development of the bajocian carbonate ramp system. Interactions between diapirism and sedimentation are summarized in an empirical model consisting of four types of depositional prisms defined by geometrical and sedimentological criteria. On a larger scale, the impact of the mini-basin on the sedimentation is characterized by a specific facies distribution in the carbonate and mixed depositional system. The high-energy granular facies are concentrated around the diapiric structures and the distal low-energy facies are deposited in the axis of the mini-basins.
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A Conceptual Model of Groundwater Flow at the Midway, Utah Fish Hatchery as Constrained by Geochemical, Physical Hydrogeological, and Geophysical MethodsDurrant, Camille 11 March 2005 (has links) (PDF)
In addition to a loss of potential revenues from Utah's $393 million sport fishing industry, the state expends millions of dollars every year on costs associated with whirling disease mitigation and prevention. A state fish hatchery at Midway, Utah was closed when the shallow unconfined aquifer being used for fish culture by spring discharge was deemed to be contaminated by whirling disease. An alternative water source may exist in a confined aquifer below this contaminated unconfined aquifer. However, the complex hydrostratigraphy presents a challenge in determining if this source is a viable resource for fish culture. Geological, physical, chemical, geophysical, and isotopic data were combined to create a conceptual model of the groundwater flow at the site and to determine the interactions this confined aquifer may have with the contaminated aquifer. This model divides groundwater at the hatchery into a shallow unconfined system, an upper confined system, and a lower confined system. The shallow unconfined system is characterized by a water table ~1m below ground surface, several active springs, fast travel times, modern water mixed with ancient hydrothermal water, relatively high TDS, and relatively enriched isotopic values. The confined aquifers have a smaller hydrothermal component, relatively depleted isotopic values, lower TDS, and modern recharge components. Two orthogonal shallow high-resolution seismic reflection profiles indicate substantial heterogeneity in the subsurface at the level of the confined systems at the hatchery. Several north-south trending normal discontinuities were interpreted as possible faults from the seismic profile oriented as a dip line, whereas the strike profile shows discontinuous layering without noticeable faulting. A well log profile for the site shows discontinuous tufa layers amid heterogeneous alluvium material. These tufa layers separate upward leaking confined aquifers from the unconfined system. It is only through the integration of several methods that such mixed systems, can be understood. In this study, the lower confined aquifer was found to be a sufficient and safe resource through the integration of numerous methods.
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