The relief is formed by the conjunction of processes that can be influenced to a greater or lesser extent by the morphostructure or morphosculpture, both of which act in the formation of the ...landscape. This work aims to, through the analysis of relief formation, provide subsidies for the studies of the run-off and the groundwater in an area of carbonate rocks in the north of Minas Gerais. The geomorphological landscape of this area is strongly influenced by morphostructural factors. Such influence is observed in the rectilinear drainage pattern of some rivers, in the presence of structural valleys, in abrupt changes in the direction of drainage net, and in scarps aligned in the same direction of joints and faults present in the area. Such structural influence is quite clear in the southern and central portions of the study area, being less significant in the northern portion, which has a much higher concentration of sinkholes than what was observed in the other areas. Considering a systemic perspective of the processes and dynamics that act on the surface and underground, this work presents these results of the formation of the geomorphological landscape so that such analysis helps in understanding the dynamics of groundwater in this area, as well as the relationship between surface waters and underground.
Investigações de campo efetivadas em trecho da borda oeste do Planalto do Espinhaço Meridional comprovaram que o seu relevo se encontra organizado em escadaria, cujos patamares modelados em rochas ...siliciclásticas, configuram distintas unidades geomorfológicas. Essa organização suscitou indagações acerca do grau de intemperismo dos solos que revestem essas unidades geomorfológicas, como também da possível relação verificada entre esse grau e a gênese e dinâmica do relevo. Na busca de responder a essas indagações foram coletadas vinte e nove amostras de solo em três perfis na Unidade Geomorfológica I, cuja altitude aproximada é de 1400m, e quatro amostras na Unidade IV, posicionada em altitude média de 1250m. As coletas ocorreram em litologias semelhantes em ambas as unidades com vistas a viabilizar a análise comparativa entre os resultados dos atributos pedológicos das amostras de solo. Em tais amostras foram elaboradas análises granulométrica, mineralógica, pH, fertilidade, ataque sulfúrico, extração de ferro livre e formas de baixa cristalinidade. Além disso, este estudo utilizou métodos de análise da micromorfologia e de obtenção de imagens em microscópio petrográfico e MEV, empregados na investigação da estrutura dos agregados e da organização dos poros de lâminas de solo dos horizontes diagnósticos de três solos da Unidade I e seis da Unidade IV. Os resultados das relações silte/argila, Ki e de Fed/Fes indicam que os solos desenvolvidos na Unidade I registram maior grau intempérico e, consequentemente, sinaliza seu estágio mais evoluído quando comparados àqueles presentes na Unidade IV. Por meio da análise micromorfológica se observou que a organização e formação da porosidade e o desenvolvimento da estrutura plásmica dos solos da Unidade I, principalmente os horizontes 2C2 do P1 e C5 do P2, sugerem ser esses mais evoluídos, quando comparados aos solos da Unidade IV. Esses resultados reforçam a hipótese de que há uma relação morfogenética entre as referidas unidades de relevo, de modo que a superfície posicionada em altimetria mais rebaixada teve sua origem a partir do desmantelamento denudacional da superfície de cimeira sob forte condicionamento da estrutura geológica regional.
Geomorphology of Pohorje mountains GAMS, I
Acta geographica Slovenica : Geografski zbornik,
01/2008, Letnik:
48, Številka:
2
Journal Article
Recenzirano
Odprti dostop
The Pohorje mountain range, young mountains with prevailing metamorphic rocks and dacite, continues to uplift above the igneous laccolith in the area of the rapid rising asthenosphere in the ...transition to the Pannonian basin also due to changes in temperature and, resultantly, of the density of uplifting dacite- and other intrusions which have not metamorphosed the surrounding sediments. On the Pohorje by the river Drava (hereinafter the Drava Pohorje), the drainage network does not match the orography, because, between the Vuzenica-Radlje basin and Fala, the Drava epigenetically deepened its gorge into the marginal range of Kobansko. Modest plateaus on the ridge of the Pohorje originate from the time when the base level maintained a cover of the so-called Eibiswald strata between the Karavanke and the Kobansko in the upper Miocene. The originally larger ridge plateau in the centre of the Pohorje was lowered by erosion and periglacial processes; it has been preserved as an inclined plateau on the Eastern Pohorje. Explained through the recent tectonic shifting, established by means of GPS in the years 1996–2002 at the peak Velika Kopa, is the southeastwards curving of the five valleys above the Legen terrace where, supposedly, original headwaters of the Spodnja Mislinja came from. Due to its geological, geomorphological and hydrological peculiarities the Legen Quaternary terrace deserves that it should be declaired the ‘geopark’, the first one in Slovenia. Even more explicit and extensive is the westwards curving of the valleys on the northern slope of the Pohorje, and their northeastward orientation in the Ribnica-Lovrenc-Selnica valley system. In the east section of the Lovrenc valley system above Fala the brook Rečnikov potok has not adjusted its course to the recent tectonic subsiding, so that its valleys run obliquely to the slope inclination. The up to 700 metres deep Mislinja rift lowered the central ridge of the Pohorje to 1299 metres. Blowing intensely across it, the northeastern Pleistocene cold winds made possible the origination of two smaller glaciers in the upper drainage basin of the Radoljna. The gently sloping Pohorje landforms are not the result of the old age but of the disintegration of granular rocks to permeable sand, above which the thick cover of continuous roots of grasses and prevailing spruce reduces the erosion.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Résumé. - L'équipe de Géomorphologie historique et climatique a été créée en 1977, dans le cadre de la restructuration du Laboratoire de Géographie physique. Elle a choisi comme thème de recherche ...majeur celui de l'évolution des paysages de la rive nord-méditerranéenne depuis 15 000 ans. Ce thème correspond à un «créneau» jusqu'à ce jour peu occupé, entre la dernière période froide et le dernier millénaire, objet, actuellement, de recherches intensives. Elle s'efforce de promouvoir une recherche pluridisciplinaire, dont ce colloque est le reflet par la présence d'historiens, palynologues, physiciens, pédologues... Elle a pour objectifs d'éclairer les relations qui se tissent entre les divers éléments du paysage- système, de reconstituer l'évolution de ce dernier au cours du temps, enfin de proposer une méthode et des modèles d'intervention aux responsables de la gestion du milieu méditerranéen (Programme M.A.B. de /'Unesco, par exemple). - Le modèle proposé ensuite (3e) décrit les modalités de l'intervention du facteur climatique. Les études de terrain visent à établir une chronologie et à isoler la marque du climat dans toute une gamme de documents.
Abstract. - Landscape evolution of the north mediterranean areas, during the post-glacial, has been selected in 1977 by the Historical and climatic Geomorphology team of the Physical Geography Laboratory. This main research theme takes place in a rather understudied gap, between the last cold period (Wisconsin, Weichselian, Wurm) and the last millenary, which support, nowadays, intensive and methodic investigations. The team plans to develop a pluridisciplinary analysis : an illustration of this tendancy is the participation of historians, panynologists, pedologists, physicians... to this meeting. Our major objectives are : understanding of landscapes as complex systems, reconstitution of landscapes dynamics along the postglacial times, elaboration of methodology and effective models for people in charge of land use and environmental programs (M.A.B.., Unesco, for instance). - The landscape model (3°) describes as far as possible the various trends of climate control. Through fieldwork we contribute to an adequate chronology of climatic variations along the Postglacial. We too appreciate the specific climatic mark in a large panel of documents (sediments, archeological evidences, texts...).
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