Fifty-three basins with area less than 9.40 km² were mapped from 1:25,000-scale aerial photographs to provide data on basin morphometry. A significantly larger number of first-order streams exist than are expected according to the regression of stream number on order for each basin. This is attributed to the incorporation of recently formed gullies into the stream network as first-order streams. Most drainage density (Dd) values are in the coarse texture category (Dd<5.0 km/km²). Higher values of Dd correspond to areas of shallow soils. Total stream frequency (F[subscribe t]) and first-order stream frequency (F₁) are closely correlated with Dd (r=+0.86 and r=+0.89, respectively), but third-order stream frequency (F₃) is not (r=+0.70). F[subscribe t] is related to Dd as follows: F[subscribe t]=0.704 (Dd)²̇⁰⁸. Values of ruggedness number (HDd) and basin magnitude indicate that all basins are high-flood potential basins. This imposes serious limitations on the development of the watershed as a whole. Weighted mean percent silt-clay (M) and channel width-depth ratio (F) for 21 cross sections of stream channels were used to define cross section stability. Catchment area above each cross section is related to its stability. As area increases cross sections change from degrading to aggrading to stable conditions. There is a more gradual increase in F with decreasing M than in streams in the mid-western United States. This is attributed to the vigorous vegetation which stabilizes channel banks in the Mandaguari watershed. Recent climatic changes in the region rendered colluvial deposits susceptible to increased erosion under the present subtropical (Cwa) climate. When saturated, the latosols and podzols there are easily eroded owing to their low cohesion (PI=0-15). Recent deforestation and seasonal burning of pastures probably exacerbate this condition, contributing to the erosion of hillsides and the formation of gullies. Large, aggressive gullies (voçorocas) 10-15 m deep and 30-40 m wide occur in association with urban centers. Management of the Riberão do Mandaguari watershed should be based on considerations of (1) threshold conditions for instability of stream channel cross sections and soils and (2) complex responses of the watershed. Recommended actions are reforestation of slopes at and above the point of maximum profile steepness, induced incision of channel filling deposits, and control of runoff from urban centers. / text

From the Proceedings of the 1971 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 22-23, 1971, Tempe, Arizona / The exploitation of southwestern rivers is discussed in the context of American intrusion, acquisition and development of Arizona. The first Americans in the region were beaver trappers who quickly decimated the Sonoran beaver but otherwise wrought little environmental impact. Immediately following the acquisition of the region by the U.S. after the Mexican war, gold miners descended upon it from California. They quickly scarred hills and streams, diverting water for placers, building piles of ugly rubble and logging off entire forests. The large numbers of people and towns that followed created a need for more home grown food products and large storage dams were soon built. When these washed out the stored floodwaters did more sharp, tragic damage downstream than even the seasonal floods of the past. The common municipal practice of dumping raw sewage into waterways soon brought water pollution. Following the national reclamation act of 1902, large dams were soon built on major waterways and the multiple use projects came into existence. Today, even the Indians, in their quest for economic betterment are destroying natural waters. They have learned a major lesson from the whites---the rivers they used only for basic needs a century ago, may be more profitable if overused without regard for tomorrow.

From the Proceedings of the 1972 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - May 5-6, 1972, Prescott, Arizona / A raingage reading is a sample from the point rainfall population of an area. The actual average rainfall on the area (watershed) is a conditional probability distribution. For the case of thunderstorm rainfall this distribution is simulated by looking at all storms that could have produced the raingage reading. The likelihood of each storm is a function of its center depth. The amount of rain dumped on the watershed by each storm is weighted by the likelihood of its occurence and the totality of such calculations is used to produce a probability distribution of rainfall on the watershed. Examples are given to illustrate the versatility of the program and its possible use in decision analysis.

The Valle de Catacamas forms a major basin along the central portion of the Guayape fault, the most prominent tectonic element of the Chortís block. The Guayape fault extends 290 km southwest from the Caribbean coast to the region of El Paraíso, Honduras, and may continue to the Pacific coast along a related prominent topographic feature, the Choluteca linear. Basins presently forming along the Guayape fault indicate that the fault is currently experiencing right-slip. The active features of the Valle de Catacamas displace older folds and reverse faults which apparently formed during an earlier period of sinistral shear. Thus, the Guayape fault has undergone at least two phases of movement, post-Cenomanian left-slip followed by the present right-slip. The geology of the valley suggests multiple stages of evolution. These include at least one period of thrust and reverse faulting, possibly associated with sinistral shear along the Guayape fault, and a recent episode of normal faulting associated with dextral shear on the Guayape fault. Thrusting of basement rocks over Jurassic strata on the south side of the valley was the earliest deformation to affect Mesozoic or Cenozoic rocks. The event can only be dated as post-Jurassic in age. The Cretaceous rocks of the Sierra de Agalta on the north side of the Valle de Catacamas are much more strongly deformed than similar rocks in central Honduras. In this range, the Aptian-Albian Atima Limestone commonly has a pervasive pressure solution cleavage which has not been reported from other locations on the Chortís block. The cleavage is apparently axial planar to the folds. The age of this deformation is constrained only as post-Cenomanian. SIR data indicate that these folds are deflected in sinistral shear near the Guayape fault. In addition, a major structural contact has a large left-lateral separation. The folds in the Sierra de Agalta are cut by the range-bounding normal fault of the Sierra de Agalta. Younger rocks are placed on older rocks by this normal fault, and fault slip data from small fault planes in the footwall block indicate normal faulting. The N 65° E strike of this normal fault, the N 35° E strike of the Guayape fault, and stress orientations inferred from fault slip data indicate that the present movement on the Guayape fault is right-slip. Fault slip data from the Guayape fault zone is heterogeneous as would be expected if two stage slip has occurred. / text

This thesis reports eight measured sections and >400 new detrital zircon U-Pb SHRIMP-II ages from the Mesoproterozoic (~1.4 Ga) upper Purcell Supergroup of southeastern British Columbia, Canada. The goal of my study is to constrain the depositional, tectonic and paleogeographic setting of the upper Purcell Supergroup. Stratigraphic sections across the Purcell Anticlinorium, constructed from measured sections, reveal three syn-depositional growth faults: (1) paleo-Hall Lake, (2) paleo-Larchwood Lake, and (3) paleo-Moyie. Stratigraphic sections were combined into a fence diagram, revealing a large north-northeast trending graben bound to the east by the paleo-Larchwood Lake fault and to the west by the paleo-Hall Lake fault. Five samples were collected for detrital zircon analysis along the eastern extent of exposed Purcell strata; one sample was collected from the western limit of strata. All samples are characterized by subordinate numbers of detrital zircons that yield Paleoproterozoic and Archean ages. Detrital zircon ages from the Sheppard Formation are dominated by 1500, 1700, 1750, and 1850 Ma grains. The overlying Gateway Formation is dominated by 1400-1450, 1700, 1850, and 1900 Ma zircon grains. The overlying Phillips, Roosville (east), and Mount Nelson formations are dominated by detrital zircon ages between 1375-1450 Ma and 1650-1800 Ma. Detrital zircon ages from the Roosville Formation (west) are dominated by 1500-1625 Ma grains. Based on the margin perpendicular orientation of the long axis of syn-depositional grabens relative to Laurentia, and on the presence of syn-depositional aged zircons through the entire sedimentary succession, we interpret the upper Purcell Supergroup to have been deposited in a transpressional pull-apart basin setting, adjacent to a convergent/translational plate margin bound to the west by terranes now located in northeastern Australia.

Bibliography: p.149-158. / xxii, 198 p. : ill. (chiefly col.), maps (chiefly col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Aims to provide a structural and stratigraphic framework for the evolution of the Roebuck Basin, and to evaluate its future petroleum potential. / Thesis (Ph.D.)--University of Adelaide, National Centre for Petroleum Geology and Geophysics, 2000

Thesis (PhD)--Macquarie University, Division of Environmental & Life Sciences, Department of Earth and Planetary Sciences, 2005. / Bibliography: leaves 202-224. / Introduction -- Geological setting of the New England Fold Belt -- Regional geophysical investigation -- Data acquisition and reduction -- Modelling and interpretation of magnetic data over the Peel Fault -- Modelling and interpretation of magnetic data over the Mooki Fault -- Gravity modelling of the Tamworth Belt and Gunnedah Basin -- Interpretation and discussion -- Conclusions. / This thesis presents new magnetic and gravity data for the Southern New England Fold Belt (SNEFB) and the Gunnedah Basin that adjoins to the west along the Mooki Fault in New South Wales. The SNEFB consists of the Tamworth Belt and Tablelands Complex that are separated by the Peel Fault. The Tablelands Complex to the east of the Peel Fault represents an accretionary wedge, and the Tamworth Belt to the west corresponds to the forearc basin. A total of five east-north-east trending gravity profiles with around 450 readings were conducted across the Tamworth Belt and Gunnedah Basin. Seven ground magnetic traverses of a total length of 60 km were surveyed across the bounding faults of the Tamworth belt, of which five were across the Peel Fault and two were across the Mooki Fault. The gravity data shows two distinct large positive anomalies, one over the Tamworth Belt, known as the Namoi Gravity High and another within the Gunnedah Basin, known as the Meandarra Gravity Ridge. All gravity profiles show similarity to each other. The magnetic data displays one distinct anomaly associated with the Peel Fault and an anomaly immediately east of the Mooki Fault. These new potential field data are used to better constrain the orientation of the Peel and Mooki Faults as well as the subsurface geometry of the Tamworth Belt and Gunnedah Basin, integrating with the published seismic data, geologic observations and new physical properties data. --Magnetic anomalies produced by the serpentinite associated with the Peel Fault were used to determine the orientation of the Peel fault. Five ground magnetic traverses were modelled to get the subsurface geometry of the serpentinite body. Modelling results of the magnetic anomalies across the Peel Fault indicate that the serpentinite body can be mostly modelled as subvertical to steeply eastward dipping tabular bodies with a minimum depth extent of 1-3 km, although the modelling does not constrain the vertical extent. This is consistent with the modelling of the magnetic traverses extracted from aeromagnetic data. Sensitivity analysis of a tabular magnetic body reveals that a minimum susceptibility of 4000x10⁻⁶cgs is needed to generate the observed high amplitude anomalies of around 2000 nT, which is consistent with the susceptibility measurements of serpentinite samples along the Peel Fault ranging from 2000 to 9000 x 10⁻⁶ cgs. Rock magnetic study indicates that the serpentinite retains a strong remanence at some locations. This remanence is a viscous remanent magnetisation (VRM) which is parallel to the present Earth's magnetic field, and explains the large anomaly amplitude over the Peel fault at these locations. The remanence of serpentinite at other localities is not consistent enough to contribute to the observed magnetic anomalies. A much greater depth extent of the Peel Fault was inferred from gravity models. It is proposed that the serpentinite along the Peel Fault was emplaced as a slice of oceanic floor that has been accreted to the front of the arc, or as diapirs rising off the serpentinised part of the mantle wedge above the supra subduction zone. / Magnetic anomalies immediately east of the Mooki Fault once suggested to be produced by a dyke-like body emplaced along the fault were modelled along two ground magnetic traverses and three extracted aeromagnetic lines. Modelling results indicate that the anomalies can be modelled as an east-dipping overturned western limb of an anticline formed as a result of a fault-propagation fold with a shallow thrust step-up angle from the décollement. Interpretation of aeromagnetic data and modelling of the magnetic traverses indicate that the anomalies along the Mooki Fault are produced by the susceptibility contrast between the high magnetic Late Carboniferous Currabubula Formation and/or Early Permian volcanic rocks of the Tamworth Belt and the less magnetic Late Permian-Triassic Sydney-Gunnedah Basin rocks. Gravity modelling indicates that the Mooki Fault has a shallow dip ( ̃25°) to the east. Modelling of the five gravity profiles shows that the Tamworth Belt is thrust westward over the Sydney-Gunnedah Basin for 15-30 km. --The Meandarra Gravity Ridge within the Gunnedah Basin was modelled as a high density volcanic rock unit with a density contrast of 0.25 tm⁻³, compared to the rocks of the Lachlan Fold Belt in all profiles. The volcanic rock unit has a steep western margin and a gently dipping eastern margin with a thickness ranging from 4.5-6 km, and has been generally agreed to have formed within an extensional basin. --The Tamworth Belt, being mainly the product of volcanism of mafic character and thus has high density units, together with the high density Woolomin Association, which is composed chiefly of chert/jasper, basalt, dolerite and metabasalt, produces the Namoi Gravity High. Gravity modelling results indicate that the anomaly over the Tamworth Belt can be modelled as either a configuration where the Tablelands Complex extends westward underthrusting the Tamworth Belt, or a configuration where the Tablelands Complex has been thrust over the Tamworth Belt. When the gravity profiles were modelled with the first configuration, the Peel Fault with a depth extent of around 1 km can only be modelled for the Manilla and Quirindi profiles, modelling of the rest of the gravity profiles indicates that the Tablelands Complex underthrust beneath the Tamworth belt at a much deeper location. / Mode of access: World Wide Web. / xi, 242 leaves ill., maps

Bibliography: p.149-158. Aims to provide a structural and stratigraphic framework for the evolution of the Roebuck Basin, and to evaluate its future petroleum potential.

Made available in DSpace on 2016-06-02T19:32:08Z (GMT). No. of bitstreams: 1 5608.pdf: 2890386 bytes, checksum: aba05420f7cabea67c4a31c1d3e38b93 (MD5) Previous issue date: 2013-10-04 / Universidade Federal de Sao Carlos / Participation, as one of the assumptions of a critical and emancipatory Environmental Education, is essential to promote the meeting of people with different knowledges that create a new knowledge, that is the dialogue.Starting from concrete experiences and seeking to substantiate them, this study aims to understand how the processes of participatory elaboration of materials with the context of Hydrographical Basins contributes to the critical educational process ( involving three dimensions : knowledge, ethical and aesthetic values and political participation ) for the proposed theme and the concept of participation, to contribute to consideration of new processes. From five interviews, the first step to answer our purpose was to analyze the participatory methodological approaches, degrees and concepts of participation and identifiable complex concept Basin in these processes. The development of materials based on the concept of participation is an alternative to overcome the linear view and simplifying the understanding of environmental issues and allows for a critical understanding of the environment and their interrelationships. The socioenvironmental issues may generate a critical and boost the subjects to participate, acting on a broader field, in decision making, as a way of strengthening their citizenship through dialogue in reflective action. The materials bring one of the most prominent themes of the present time, namely the management of water in the context of watersheds or hydrological basins. The holistic concept of basins can help the educational process as a means of integrating the collective. And, in this sense, the materials elaboration through participative methodologies represents a constitutive process to the remaking of the relationship between society and environment, and represents an act of citizen participation. When we understand that the major product of the process is the shaping experience and not only the materials, we understand the importance of encouraging participative methodologies. Furthermore, we believe that a good practice that should be assumed by a/one educator/environmental educator when facing a new process of developing materials based on the evaluation is guided by similar materials. The second stage of the research resulted from analysis of seven materials, resulting from projects systematized interviews, aiming the occurrence of the three dimensions of educational practice which we consider inseparable in an effective work of Environmental Education. The exercise of reflection on past experience provides the teacher/educator the opportunity to learn and not to stumble on the same obstacles encountered by other/the educators/s, thus avoiding presenting the same weaknesses. We understand that this reflection brings methodological contributions to research in environmental education, while, at some point, innovates to analyze and reflect on participation, a concept that permeates the educational action critique, and on the concept and theme Hydrographical Basins. A reflective analysis of the processes of development and some aspects of the materials showed that we deem interesting for the field, and so we gathered in ten guidelines for the participatory preparation of materials to support environmental education. The importance of having guidelines is to support the initiative to the dialogue and to the transforming actions. / A participação, dentre os pressupostos de uma Educação Ambiental crítica e emancipatória, é fundamental para que ocorra o encontro de pessoas com diferentes saberes na criação de um novo saber, ou seja, o diálogo. Partindo de experiências concretas e buscando compreender sua fundamentação, este trabalho teve como objetivo compreender como os processos de elaboração participativa de materiais com o contexto de Bacia Hidrográfica contribui com o processo educativo crítico (envolvendo as três dimensões: conhecimentos, os valores éticos e estéticos e a participação política) referentes a temática proposta e ao conceito de participação, visando contribuir para reflexão de novos processos. A partir de cinco entrevistas, a primeira etapa para responder nosso objetivo foi analisar os caminhos metodológicos participativos, os graus e os conceitos de participação identificáveis e o complexo conceito de Bacia Hidrográfica nestes processos. A elaboração de materiais baseados no conceito de participação é uma alternativa para a superação da visão linear e simplificadora na compreensão das questões ambientais e possibilita um entendimento crítico do ambiente e suas interrelações. Os temas socioambientais podem gerar uma postura crítica e impulsionar os sujeitos a participarem, atuando em um campo mais amplo, na tomada de decisões, como uma forma de fortalecer sua cidadania por meio do diálogo na ação reflexiva. Os materiais trazem um dos temas mais eminentes da atualidade, a gestão das águas no contexto de Bacias Hidrográficas. O conceito holístico de bacias pode auxiliar no processo educativo como integrador do coletivo. Nesse sentido, a elaboração de materiais por metodologias participativas representa um processo formativo para a transformação das relações entre sociedade e ambiente e representa um exercício de participação cidadã. Ao entendermos que o produto maior do processo é a experiência formativa e não somente os materiais, compreendemos a importância de incentivar o uso de metodologias participativas para a elaboração de materiais. Além disso, acreditamos que uma boa prática que deve ser assumida por uma/um educadora/educador ambiental quando enfrenta um novo processo de elaboração de materiais é partir da avaliação pautada em materiais similares. A segunda etapa da pesquisa resultou da análise de sete materiais, resultantes dos projetos sistematizados das entrevistas, visando a ocorrência das três dimensões da prática educativa que consideramos indissociáveis em um trabalho efetivo de Educação Ambiental. O exercício de reflexão sobre experiências anteriores proporciona a educadora/educador a possibilidade de aprender e de não tropeçar nos mesmos obstáculos encontrados por outras/os educadoras/es, evitando assim apresentar as mesmas fragilidades. Entendemos que esta reflexão traz contribuições metodológicas à pesquisa em Educação Ambiental, ao passo que, em certo ponto, inova ao analisar e refletir sobre a participação, conceito que permeia a ação educativa crítica, e sobre o conceito e a temática de Bacias Hidrográficas. A análise reflexiva dos processos de elaboração e dos materiais evidenciou alguns aspectos que julgamos interessantes para o campo, e por isso reunimos em dez diretrizes para a elaboração participativa de materiais de apoio a Educação Ambiental. A importância de reunir diretrizes é a de apoiar iniciativas para o diálogo e para as ações transformadoras.

xv, 136 p. : ill. (some col.) / The Pacific Northwest of the United States has been tectonically and magmatically active with the accretion of the Farallon oceanic terrane "Siletzia" ∼50 Ma. The accretion of Siletzia terminated the flat-slab subduction of the Farallon slab and initiated the Cascadia subduction zone. In this dissertation, I focus on both the large-scale tectonic structures preserved seismically in the crust and upper mantle, and the small-scale, short-term aseismic processes on the plate interface. I measure the shear-wave splitting trends around eastern Oregon with a dataset of ∼200 seismometers from 2006-2008 to analyze the upper-mantle anisotropy. The delay times between splitted shear-waves range from 0.8 s to 2.7 s. In the High Lava Plains, the fast polarization direction is approximately E-W with average delay time ∼1.8 s. I infer that there must be significant active flow in a roughly E-W direction in the asthenosphere beneath this area. The splitting pattern is more variable and complicated in NE Oregon, where the crust and mantle lithosphere may be a significant contribution. In terms of the imaged seismic velocity structures, I infer that the Eocene sedimentary basins in south-central Washington lie above a magmatically underplated crust of extended Siletzia lithosphere. Siletzia thrusts under the pre-accretion forearc, and its southeast termination is especially strong and sharp southeast of the Klamath-Blue Mountains gravity lineament. Magmatic intrusion has increased upper crustal velocity as in the less active Washington Cascades, but the higher temperatures beneath the magmatically active Oregon Cascades have a dominating effect. To better understand the physical mechanism of slow slip events on the plate interface, I explore the scaling relationships of various source parameters collected mainly from subduction zones worldwide and also other tectonic environments. The source parameter scaling relationships of slow slip events highlight the similarities and differences between slow slip phenomena and earthquakes. These relationships hold implications for the degree of heterogeneity and fault healing characteristics. The recurrence statistics of northern Cascadia events behave weakly time predictable and moderately anti-slip predictable, which may indicate healing between events. This dissertation includes co-authored materials both previously published and submitted for publication. / Committee in charge: Eugene Humphreys, Chairperson; David Schmidt, Member; Ray Weldon, Member; James Isenberg, Outside Member