• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 10
  • 4
  • 3
  • 3
  • 1
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 25
  • 25
  • 6
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Cestopis jako praktická pomůcka ve výuce regionálního zeměpisu na 2. stupni ZŠ (na příkladu výuky Jihozápadní Asie) / A travel book as a practical tool for teaching regional Geography in secondary school (for example teaching of South-western Asia)

NEDOROSTOVÁ, Alena January 2011 (has links)
The diploma thesis is called ?A travel book as a practical tool for teaching regional Geography in secondary school (for example teaching of South-western Asia).? It consists of two parts. The first part is focused on the analysis of literature and the materials that refer to the topic of my diploma thesis (textbooks of Geography, travelogue and popularly educational literature). The next theme of this thesis is a travel book as a term, and possibilities of the usage of literature connected with travelling as a tool of teaching practice in secondary school. The main part of the thesis applies to the process of teaching text as a teaching guide that uses elements of a travel book for teaching regional geography of states in South-western Asia in secondary school. The teaching text is divided into two parts ? travel and teaching that introduces basic geographic signs of the whole region of South-western Asia. Each chapter is finished with summary, questions and tasks. The readers are progressively taken to Iran as a chosen representative of the region in each part of travel story.
12

Suburbanizace v zázemí Českých Budějovic - jihozápadní a jižní sektor / Suburbanization of České Budějovice - southern and south-western sectors

JURÁK, Ondřej January 2012 (has links)
Diploma thesis resulted from a part of the experimental project of the department of geography ? Pedagogical Faculty, University of South Bohemia in České Budějovice, which was supported with the grant agency sb. u. (grant no. 072/2010/s). It discusses the problems of suburbanization in the agglomeration of České Budějovice, specifically the suburbs of the southern and south-western sectors. Exploration included various aspects of suburban geography, where there were elaborate social, economic and demographic problems. I observe suburban transformation from the socialist and post-socialist period to the present. Due to the complex problems of the topic, three main aims were identified to reflect the substance of the work. To achieve them, the literature review revealed useful information and thematic maps were created. Data was collected in the chosen localities and analysis of dates, terrain mapping, dialogues and examinations with mayors of the municipalities were carried out. The theoretical part describes chosen characterizations of the social-geographical world, for example inhabitants, industry, agriculture, services, travelling and transport. The following chapters discuss aspects of the exploration of suburbanization, according to theories and literature. They explain reasons and conditions of suburban actions in the worlds? developed countries, suburbanization in the U. S. A. and in the western and post-socialist Europe. The practical part of the work used quantitative research, included collecting data about the typology of the seats, analysis of the development of inhabitants in suburban municipalities, the age of the permanently inhabited houses, number of built flats, processions and another problems in the suburbs. The results of this research can be used as a resource for information about the suburban development of smaller towns. The work is able to serve not only as informative material for the mayors of individual municipalities but is also able to help the municipal authorities of České Budějovice.
13

The technologisation of practice in early childhood nursing : collaborating for innovation and change

Greenfield, David, Public Health & Community Medicine, Faculty of Medicine, UNSW January 2004 (has links)
There is a need for research to understand change processes and knowledge management in health service organisations, and indeed public sector organisations in general. This research seeks to explain how knowledge becomes formulated and thereby mobile, and also how practice has come to be established, visibilised and thereby sustained in a specific context. Exploring practice within a health service organisation, and in particular a public health service organisation, is a particular feature of this research. The research demonstrates how collaboration becomes necessitated under pressure of enacting increasingly complex work activities, an outcome being changing practices and extended accountability relationships which enacts discipline while realising expertise. Using an ethnographic approach, the research explores how the practice of early childhood nursing in the South Western Sydney Area Health Service became a specialised expert undertaking. The research examines how change has occurred, whereby early childhood nursing was refined from being one part of the generalist community nursing practice to being a specialised practice through the increasing technologisation of practice. The technologisation of practice refers to the artefacts, conduct and the processes through which the conceptualisation and enactment of early childhood nursing has become increasingly standardised. Through the technologisation of practice explicit knowledge becomes distributed within the artefacts for practice and tacit knowing becomes distributed across, and is continually enacted by, the collaboration of the practice community. There are four interrelated aspects to the technologisation of practice. Firstly, the technologisation of practice involves standardising the conceptualisation and enactment of practice through constructing a multi-dimensional practice resource within a community of practice. Secondly, the technologisation of practice involves the mobilisation and refinement of the multi-dimensional practice resource to realise a practice network involving extended relationships of accountability. These relationships of accountability are within a profession and also with other professionals. Thirdly, the technologisation of practice involves the ongoing enactment of accountability in a collaborative community of practice. The research shows that a team can become a collaborative community by constructing an accountability context, reorganising and facilitating the team, and then amalgamating the organising and service delivery activities through integrating formal meetings and informal interactions. Fourthly, the technologisation of practice involves the collaborative community assemblage and/or appropriation of further technologies into practice thereby strengthening the local and extended relationships of accountability and expanding the boundaries of practice. The research describes how the technologisation of practice is the enactment of a number of mutually enabling practice dualities, which together simultaneously discipline and realise expertise. The interrelated practice dualities are individual-community, subjective-objective, local-global, formal-informal and governmentality-communal self-governance. The situatedness of practice is shown to necessitate a subjectivity-objectivity duality, whereby individual and communal experience is drawn upon to see through the otherwise opaque nature of statistics and information. The alignment of practice with the broader organisation and professional colleagues realises a local-global duality, whereby the community's local understandings are informed and shaped by distant issues. The formal-informal duality is a mechanism by which practice is increasingly collaboratively conceptualised and enacted, and thereby standardised. Individual and communal 'expertise' becomes realised through the assemblage and appropriation of organising and transforming tools and artefacts, or alternatively technologies. At the same time, the community in defining the use of such technologies as competent practice is disciplining their own conduct. Through this action a governmentality-communal self-governance duality is realised as the nursing community pursues expertise while disciplining themselves; by engaging in collaborative interactions and using standardised technologies the community constructs and makes visible their knowing, practice and expertise.
14

Chemnitzer Geschichtskalender / Chemnitz Historical Calendar

06 January 2017 (has links)
Reihe digitaler Kalenderblätter, die historische Beiträge mit Bezug zur Region Chemnitz-Südwestsachsen veröffentlicht. / Series of digital calendar sheets to publish historical contributions related to the region of Chemnitz-South West Saxony.
15

Sůl nad zlato? Právní a ekonomické postavení města Prachatice v pozdním středověku / Salt More Than Gold? The Legal and Economic Status of the Town Prachatice in the Late Middle Ages

Večeřová, Veronika January 2017 (has links)
This master thesis inquires into selected chapters from the late medieval history of the town Prachatice. The first part of the thesis deals with the unclear legal status of the town and with the issue of its promotion to the royal town and its subsequent pawnings in the 15th century. It is a question that has not been sufficiently reflected in literature yet and there is also no agreement whether Prachatice was a royal pawned town or a liege town. The second part discusses the issue of the economic status of the town Prachtice in the context of the Southern Bohemian salt business wherein Prachatice played a crucial role. This part of the thesis is based on a thorough analysis of the staple right of the town Prachatice and the right which covered the compulsory direction of the routes. Further, it deals with the competition of the town Prachatice in the import of salt to Bohemia and with the outline of the directions of the routes that were starting in Prachatice. These routes were the matters of disputes with other involved towns. This thesis is delimited by the period of the Late Middle Ages until the beginning or the first quarter of the 16th century. The attention is paid especially to the unsettled 15th century which brought a lot of turns of events into the history of the town. Key words:...
16

On Death in the Mesolithic : Or the Mortuary Practices of the Last Hunter-Gatherers of the South-Western Iberian Peninsula, 7th–6th Millennium BCE

Peyroteo Stjerna, Rita January 2016 (has links)
The history of death is entangled with the history of changing social values, meaning that a shift in attitudes to death will be consistent with changes in a society’s world view. Late Mesolithic shell middens in the Tagus and Sado valleys, Portugal, constitute some of the largest and earliest burial grounds known, arranged and maintained by people with a hunting, fishing, and foraging lifestyle, c 6000–5000 cal BCE. These sites have been interpreted in the light of economic and environmental processes as territorial claims to establish control over limited resources. This approach does not explain the significance of the frequent disposal of the dead in neighbouring burial grounds, and how these places were meaningful and socially recognized. The aim of this dissertation is to answer these questions through the detailed analysis of museum collections of human burials from these sites, excavated between the late nineteenth century and the 1960s. I examine the burial activity of the last hunter-gatherers of the south-western Iberian Peninsula from an archaeological perspective, and explain the burial phenomenon through the lens of historical and humanist approaches to death and hunter-gatherers, on the basis of theoretical concepts of social memory, place, mortuary ritual practice, and historical processes. Human burials are investigated in terms of time and practice based on the application of three methods: radiocarbon dating and Bayesian analysis to define the chronological framework of the burial activity at each site and valley; stable isotope analysis of carbon and nitrogen aimed at defining the burial populations by the identification of dietary choices; and archaeothanatology to reconstruct and define central practices in the treatment of the dead. This dissertation provides new perspectives on the role and relevance of the shell middens in the Tagus and Sado valleys. Hunter-gatherers frequenting these sites were bound by shared social practices, which included the formation and maintenance of burial grounds, as a primary means of history making. Death rituals played a central role in the life of these hunter-gatherers in developing a sense of community, as well as maintaining social ties in both life and death.
17

Interações tróficas de peixes marinhos no Estado de São Paulo: banco de dados e comparações espaço-temporais / Trophic interactions of marine fish in the State of São Paulo: database and spatial-temporal comparisons

Lopez, Juliana Pierrobon 13 February 2012 (has links)
Os ecossistemas marinhos do Estado de São Paulo sofrem intensa pressão antrópica. Considerando que os estudos tróficos de peixes são essenciais para o manejo desses ecossistemas e para a gestão pesqueira, foi construído um banco de dados alimentares de peixes para sintetizar o conhecimento já obtido na área. Foram inseridos, individualmente ou agrupados, dados primários (não-publicados) e secundários (publicados), representando 142 espécies. Com base nesse banco, foi comparada a dieta dos peixes nos sistemas de plataforma continental do litoral Norte, plataforma continental do litoral Centro, canal de São Sebastião, baía de Santos e complexo estuarino-lagunar de Cananéia-Iguape. Foi verificado que a dieta variou entre os sistemas, provavelmente devido à variação na disponibilidade alimentar. Na plataforma Norte, foi analisada a variação sazonal (outono/inverno e primavera/verão) da dieta e verificou-se que a diferença interespecífica sobrepujou a diferença intraespecífica temporal. A dieta da corvina (Micropogonias furnieri), espécie abundante e de grande importância comercial, foi analisada em detalhe e concluiu-se que ela possui estratégia alimentar mista, consumindo majoritariamente alguns itens (poliquetas e camarões) e esporadicamente outros. Foram elaboradas considerações sobre a publicação de dados científicos brutos e sobre a metodologia aplicada aos estudos de conteúdo estomacal. / The marine ecosystems of São Paulo State are under intense anthropic pressure. Considering that trophic studies of fishes are essential to the management of ecosystems and fisheries, a fish stomach content database was built in order to summarize the available data in the region. Primary (unpublished) and secondary (published) data were inserted, representing 142 species. Based on this database, diet compositions of fishes were compared among 5 marine systems of São Paulo State (North continental shelf, Central continental shelf, São Sebastião channel, Santos bay and Cananéia lagoon estuarine system). It was observed that diet composition varied among systems, probably associated to the food resource availability. Seasonal comparison (autumn/winter and spring/summer) performed in the North continental shelf showed that the interspecific variation was larger than the intraspecific temporal variation. Diet of Micropogonias furnieri, an abundant and commercially important species, was analyzed in detail and it was concluded that it has a mixed feeding strategy, consuming mostly few items (polychaetes and shrimps) and sporadically many others. Some considerations on scientific raw data publication and on methodology of stomach content studies were made.
18

A litosfera das Bacias do Chaco-Paraná e Paraná integrando gravimetria e sondagens magnetotelúricas: novos vínculos à tectônica do Gondwana Sul-Ocidental / Chaco-Paraná and Paraná Basins lithosphere through gravity and magnetotelluric soundings: new constraints to the South-Western Gondwana tectonics

Gabriel Negrucci Dragone 11 July 2018 (has links)
Nesta tese, dados gravimétricos terrestres e de satélite foram combinados revelando que as bordas oeste e sul da Bacia do Paraná são caracterizadas por um forte gradiente que se estende por 2000 km, desde o cráton Rio Apa até a margem continental Atlântica na latitude do Sinclinal de Torres. Enquanto a Bacia do Paraná é caracterizada por anomalias Bouguer negativas (~-80 mGal), os crátons Rio de la Plata, Rio Tebicuary e Rio Apa e a Bacia do Chaco-Paraná são marcados por anomalias Bouguer positivas (~10 mGal). Dados sismológicos e de compensação isostática permitiram correlacionar a variação regional da amplitude das anomalias Bouguer à espessura crustal, de ~40 km na Bacia do Paraná para 30-35 km nos crátons. Essas observações geofísicas e a ocorrência de granitos cálcio-alcalinos de idade Neoproterozoica-Cambriana ao longo do gradiente gravimétrico indicam um ambiente tectônico de colisão e zona de subducção. A essa descontinuidade de escala litosférica denominamos Zona de Sutura do Oeste do Paraná (WPS Western Paraná Suture shear/zone). Dois perfis magnetotelúricos (MT) foram coletados para estudar a natureza e a estrutura elétrica da crosta e do manto litosférico através da WPS. O primeiro perfil se estende por 830 km desde o cráton Rio de la Plata, no Uruguai, até a parte sul da Bacia do Paraná. Modelagem inversa 2-D desses dados mostra que o manto superior no cráton Rio de la Plata é bastante resistivo (~2000 m) até 250 km de profundidade, enquanto o manto superior na Bacia do Paraná é geralmente mais condutivo e heterogêneo. Com base numa descontinuidade lateral de escala litosférica bem definida no modelo de resistividade, o limite nordeste do cráton Rio de la Plata é redefinido no norte do bloco Valentines. O segundo perfil se estende por 450 km na Argentina, entre o cráton Rio Tebicuary e a Bacia do Paraná. No modelo MT o cráton Rio Tebicuary é caracterizado por um manto superior resistivo (2000 m) até 150 km de profundidade. A litosfera na Bacia do Paraná é menos resistiva (~500 m) e provavelmente menos espessa (~80 km). Um perfil MT entre o cráton Rio Apa e a Bacia do Paraná mostra estrutura geoelétrica similar. As estruturas elétricas observadas, juntamente com dados geocronológicos, geoquímicos, sismológicos e densidade, sugerem processos de refertilização na litosfera da Bacia do Paraná. Sucessões de anomalias condutivas em antigas zonas de sutura e resistivas em blocos e terrenos juvenis nos modelos geoelétricos, integradas a dados geológicos, indicam um processo de acresção horizontal e uma progressão de subducções de placas litosféricas oceânicas, sendo a mais jovem sob a litosfera continental da Bacia do Paraná. Os resultados obtidos mostram que a WPS é uma descontinuidade litosférica de primeira ordem que marca o fechamento de um oceano durante os estágios finais da formação do Gondwana Sul-Ocidental no Neoproterozoico-Cambriano. / In this thesis, terrestrial and satellite gravity data were integrated revealing a steep gravity gradient at the western and southern borders of the Paraná Basin. This gradient extends for 2,000 km from the Rio Apa craton to the Brazilian Atlantic margin at Torres Syncline latitude. Negative Bouguer anomalies (~-80 mGal) occur over the Paraná Basin, whereas positive anomalies are observed at Rio de la Plata, Rio Tebicuary and Rio Apa cratons, as well as Chaco-Paraná Basin. Seismological data and isostasy correlate the gravity gradient with crustal thickness variation, being thicker in the Paraná Basin (~40 km) and shallower in the cratons (~35 km). These geophysical observations and the presence of Neoproterozoic calc-alkaline granites along the gravity gradient suggest a collisional and subduction tectonic setting. This lithospheric discontinuity is hereafter referred to as Western Paraná Suture/shear zone (WPS). Two magnetotelluric (MT) profiles perpendicular to WPS were set up to study the electrical structure and nature of the crust and lithospheric mantle across the suture zone. The first profile, 830 km long, extends northward from Rio de la Plata craton, in Uruguay, to Paraná Basin southern border. 2-D inversion of this MT profile shows that the Rio de la Plata craton upper mantle is highly resistive (~2000 m) down to 250 km depth, whereas the Paraná Basin lithosphere is conductive and heterogeneous. Based on a lithospheric-scale lateral discontinuity in the resistivity model, the Rio de la Plata craton northern limit is redefined to the Valentines block northern limit. The second profile is 450 km long and extends from Rio Tebicuary craton to the Paraná Basin, and all stations are in Argentina. The MT model shows that Rio Tebicuary craton is characterized by a resistive lithosphere (2000 m) down to 150 km depth. The Paraná Basin lithosphere is less resistive (~500 m) and probably thinner (~80 km). Previous MT study between the Rio Apa craton and the Paraná basin, to the north, shows a similar electrical structure. These electrical characteristics, integrated with geochronological, geochemical, seismological and density data, suggest that Paraná Basin lithosphere underwent refertilization episodes. In the geoelectrical models, a series of resistive blocks and juvenile terrains and conductive anomalies in suture zone relics, integrated with geological data, suggest a horizontal accretionary process by means of progressive oceanic lithospheres subductions, the youngest one occurring below the Paraná Basin continental lithosphere. Altogether, these results show that the WPS is a first order lithosphere discontinuity, a site of an ocean closure during the South-Western Gondwana late stages of amalgamation in Neoproterozoic/Cambrian times.
19

Interações tróficas de peixes marinhos no Estado de São Paulo: banco de dados e comparações espaço-temporais / Trophic interactions of marine fish in the State of São Paulo: database and spatial-temporal comparisons

Juliana Pierrobon Lopez 13 February 2012 (has links)
Os ecossistemas marinhos do Estado de São Paulo sofrem intensa pressão antrópica. Considerando que os estudos tróficos de peixes são essenciais para o manejo desses ecossistemas e para a gestão pesqueira, foi construído um banco de dados alimentares de peixes para sintetizar o conhecimento já obtido na área. Foram inseridos, individualmente ou agrupados, dados primários (não-publicados) e secundários (publicados), representando 142 espécies. Com base nesse banco, foi comparada a dieta dos peixes nos sistemas de plataforma continental do litoral Norte, plataforma continental do litoral Centro, canal de São Sebastião, baía de Santos e complexo estuarino-lagunar de Cananéia-Iguape. Foi verificado que a dieta variou entre os sistemas, provavelmente devido à variação na disponibilidade alimentar. Na plataforma Norte, foi analisada a variação sazonal (outono/inverno e primavera/verão) da dieta e verificou-se que a diferença interespecífica sobrepujou a diferença intraespecífica temporal. A dieta da corvina (Micropogonias furnieri), espécie abundante e de grande importância comercial, foi analisada em detalhe e concluiu-se que ela possui estratégia alimentar mista, consumindo majoritariamente alguns itens (poliquetas e camarões) e esporadicamente outros. Foram elaboradas considerações sobre a publicação de dados científicos brutos e sobre a metodologia aplicada aos estudos de conteúdo estomacal. / The marine ecosystems of São Paulo State are under intense anthropic pressure. Considering that trophic studies of fishes are essential to the management of ecosystems and fisheries, a fish stomach content database was built in order to summarize the available data in the region. Primary (unpublished) and secondary (published) data were inserted, representing 142 species. Based on this database, diet compositions of fishes were compared among 5 marine systems of São Paulo State (North continental shelf, Central continental shelf, São Sebastião channel, Santos bay and Cananéia lagoon estuarine system). It was observed that diet composition varied among systems, probably associated to the food resource availability. Seasonal comparison (autumn/winter and spring/summer) performed in the North continental shelf showed that the interspecific variation was larger than the intraspecific temporal variation. Diet of Micropogonias furnieri, an abundant and commercially important species, was analyzed in detail and it was concluded that it has a mixed feeding strategy, consuming mostly few items (polychaetes and shrimps) and sporadically many others. Some considerations on scientific raw data publication and on methodology of stomach content studies were made.
20

A litosfera das Bacias do Chaco-Paraná e Paraná integrando gravimetria e sondagens magnetotelúricas: novos vínculos à tectônica do Gondwana Sul-Ocidental / Chaco-Paraná and Paraná Basins lithosphere through gravity and magnetotelluric soundings: new constraints to the South-Western Gondwana tectonics

Dragone, Gabriel Negrucci 11 July 2018 (has links)
Nesta tese, dados gravimétricos terrestres e de satélite foram combinados revelando que as bordas oeste e sul da Bacia do Paraná são caracterizadas por um forte gradiente que se estende por 2000 km, desde o cráton Rio Apa até a margem continental Atlântica na latitude do Sinclinal de Torres. Enquanto a Bacia do Paraná é caracterizada por anomalias Bouguer negativas (~-80 mGal), os crátons Rio de la Plata, Rio Tebicuary e Rio Apa e a Bacia do Chaco-Paraná são marcados por anomalias Bouguer positivas (~10 mGal). Dados sismológicos e de compensação isostática permitiram correlacionar a variação regional da amplitude das anomalias Bouguer à espessura crustal, de ~40 km na Bacia do Paraná para 30-35 km nos crátons. Essas observações geofísicas e a ocorrência de granitos cálcio-alcalinos de idade Neoproterozoica-Cambriana ao longo do gradiente gravimétrico indicam um ambiente tectônico de colisão e zona de subducção. A essa descontinuidade de escala litosférica denominamos Zona de Sutura do Oeste do Paraná (WPS Western Paraná Suture shear/zone). Dois perfis magnetotelúricos (MT) foram coletados para estudar a natureza e a estrutura elétrica da crosta e do manto litosférico através da WPS. O primeiro perfil se estende por 830 km desde o cráton Rio de la Plata, no Uruguai, até a parte sul da Bacia do Paraná. Modelagem inversa 2-D desses dados mostra que o manto superior no cráton Rio de la Plata é bastante resistivo (~2000 m) até 250 km de profundidade, enquanto o manto superior na Bacia do Paraná é geralmente mais condutivo e heterogêneo. Com base numa descontinuidade lateral de escala litosférica bem definida no modelo de resistividade, o limite nordeste do cráton Rio de la Plata é redefinido no norte do bloco Valentines. O segundo perfil se estende por 450 km na Argentina, entre o cráton Rio Tebicuary e a Bacia do Paraná. No modelo MT o cráton Rio Tebicuary é caracterizado por um manto superior resistivo (2000 m) até 150 km de profundidade. A litosfera na Bacia do Paraná é menos resistiva (~500 m) e provavelmente menos espessa (~80 km). Um perfil MT entre o cráton Rio Apa e a Bacia do Paraná mostra estrutura geoelétrica similar. As estruturas elétricas observadas, juntamente com dados geocronológicos, geoquímicos, sismológicos e densidade, sugerem processos de refertilização na litosfera da Bacia do Paraná. Sucessões de anomalias condutivas em antigas zonas de sutura e resistivas em blocos e terrenos juvenis nos modelos geoelétricos, integradas a dados geológicos, indicam um processo de acresção horizontal e uma progressão de subducções de placas litosféricas oceânicas, sendo a mais jovem sob a litosfera continental da Bacia do Paraná. Os resultados obtidos mostram que a WPS é uma descontinuidade litosférica de primeira ordem que marca o fechamento de um oceano durante os estágios finais da formação do Gondwana Sul-Ocidental no Neoproterozoico-Cambriano. / In this thesis, terrestrial and satellite gravity data were integrated revealing a steep gravity gradient at the western and southern borders of the Paraná Basin. This gradient extends for 2,000 km from the Rio Apa craton to the Brazilian Atlantic margin at Torres Syncline latitude. Negative Bouguer anomalies (~-80 mGal) occur over the Paraná Basin, whereas positive anomalies are observed at Rio de la Plata, Rio Tebicuary and Rio Apa cratons, as well as Chaco-Paraná Basin. Seismological data and isostasy correlate the gravity gradient with crustal thickness variation, being thicker in the Paraná Basin (~40 km) and shallower in the cratons (~35 km). These geophysical observations and the presence of Neoproterozoic calc-alkaline granites along the gravity gradient suggest a collisional and subduction tectonic setting. This lithospheric discontinuity is hereafter referred to as Western Paraná Suture/shear zone (WPS). Two magnetotelluric (MT) profiles perpendicular to WPS were set up to study the electrical structure and nature of the crust and lithospheric mantle across the suture zone. The first profile, 830 km long, extends northward from Rio de la Plata craton, in Uruguay, to Paraná Basin southern border. 2-D inversion of this MT profile shows that the Rio de la Plata craton upper mantle is highly resistive (~2000 m) down to 250 km depth, whereas the Paraná Basin lithosphere is conductive and heterogeneous. Based on a lithospheric-scale lateral discontinuity in the resistivity model, the Rio de la Plata craton northern limit is redefined to the Valentines block northern limit. The second profile is 450 km long and extends from Rio Tebicuary craton to the Paraná Basin, and all stations are in Argentina. The MT model shows that Rio Tebicuary craton is characterized by a resistive lithosphere (2000 m) down to 150 km depth. The Paraná Basin lithosphere is less resistive (~500 m) and probably thinner (~80 km). Previous MT study between the Rio Apa craton and the Paraná basin, to the north, shows a similar electrical structure. These electrical characteristics, integrated with geochronological, geochemical, seismological and density data, suggest that Paraná Basin lithosphere underwent refertilization episodes. In the geoelectrical models, a series of resistive blocks and juvenile terrains and conductive anomalies in suture zone relics, integrated with geological data, suggest a horizontal accretionary process by means of progressive oceanic lithospheres subductions, the youngest one occurring below the Paraná Basin continental lithosphere. Altogether, these results show that the WPS is a first order lithosphere discontinuity, a site of an ocean closure during the South-Western Gondwana late stages of amalgamation in Neoproterozoic/Cambrian times.

Page generated in 0.0664 seconds