Firn line elevation of the Dickson Land peninsula

The Dickson Land peninsula is located in central West-Spitsbergen between the NNE branches of Isfjorden. The climatic firn line lying at 500 m causes plateau glaciers with outlet tongues which are characteristic of S-Dickson Land. The distribution of valley glaciers and the variations of the orographic firn line depend on wind direction. In comparing the firn lines established by the methods of LICHTENECKER (1938) and VISSER (1938), to the values calculated by the method of v. HÖFER (1879), differences of up to l07 m are found. These differences may depend on the inclination and distance relationships of the glaciers above and below the real firn lines. During the latest glacial advance, Dickson Land was located on the peripheries of two local glaciation centers. At that time an inland glaciation of West-Spitsbergen did not exist . The formation of a subglacial channel system dates back to the maximum extent of the late glacial phase before 17500 B.P, (+2000/-1375 years). A correlation of postglacial stadia and 14C dated marine terraces (FEYLING-HANSSEN & OLSSON, 1960; FEYLING-HANSSEN, 1965) is possible. Considering isostatic movement and the difference between calculated and real firn lines, a postglacial stadium at about 10400 B. P. can be reconstructed with a firn line lying 265 m above former sea level. On average, the absolute depression below the recent firn line amounted to 246 m. Stagnation at 9650 B.P. coincided with a firn line at 315 m above former sea level and a depression of 173 m. Around 1890 A.D., glacial fluctuations corresponded to a firn line at 415 m (depression: 64 m). To some extent the morphology of the main valleys appears to depend on structure and petrography. Therefore their value as indicators of former glaciations is questionable. The periglacial forms are shown on a large-scale map. At the time of the "Holocene warm interval", between 7000 and 2000 B.P. (FEYLING-HANSSEN, 1955a, 1965), an increase of periglacial activity seems likely. This can be explained by a simultaneous increase in the depth of the active layer in both soil and bedrock.

Incisión fluvial del río Darro durante el periodo 1890-2010 en el sector urbano de Granada (Alambra-Valparaíso, España) determinada a partir de fotografías históricas

En este trabajo se calcula la tasa media de incisión fluvial del río Darro (Granada, España) durante el periodo 1890-2010 en su tramo urbano (sector Alhambra-Valparaíso). Para ello se han utilizado fotografías históricas en las que aparece dicho río, a partir de las cuales se ha podido determinar la posición del cauce en el momento en el que se realizaron las fotografías. La comparación con los escenarios actuales de tales imágenes ha permitido determinar la diferencia de altura del cauce a través de medidas de cotas absolutas realizadas mediante teodolito. Esta metodología ha permitido estimar de modo cuantitativo un índice de encajamiento vertical medio del río de 1,05 cm/año para el periodo histórico considerado.

Aufbau und Untergliederung des Niederterrassenkörpers der Unterelbe

Das untere Elbtal hat während der Weichsel-Kaltzeit (120.000-10.000 vor heute) als nordwestliche Fortsetzung der drei großen mitteldeutschen und polnischen Urstromtäler gedient (GIRARD 1855). Die drei Urstromtäler sind jeweils der Haupteisrandlage einer Vereisungsphase zuzuordnen und nacheinander in Funktion gewesen (KEILHACK 1887, 1898). Die drei Urstromtäler vereinigen sich nahe dem Elbknie bei Havelberg. Von dort aus sind die Schmelzwässer des skandinavischen Inlandeises gemeinsam mit den Flußwässern aus dem mitteldeutschen Einzuggebiet der Elbe zur Nordsee abgeflossen. Dazugekommen sind Schmelzwasserabflüsse vom Eisrand, der während des Höchststandes der Vereisung nur etwa 10 km vom Elbtal entfernt gelegen hat. Trotz der wichtigen Funktion des Elbe-Urstromtales bei der Entwässerung Mitteleuropas hat es bisher keine zusammenfassende Bearbeitung der weichselkaltzeitlichen Urstromtal - Ablagerungen gegeben. Ausgangspunkt für die vorliegende Arbeit ist die Frage gewesen, ob sich die weichselkaltzeitlichen Urstromtalabiagerungen, die als Niederterrassen-Ablagerungen bezeichnet werden, petrographisch von liegenden Schichteinheiten abtrennen lassen. Weitere thematische Schwerpunkte sind die Anlage und Entwicklung des Elbe-Urstromtales sowie die Untergliederung der dazugehörigen Sedimente. Geographischer Ausgangspunkt der Untersuchungen ist der Raum Gorleben. Dort wurde die kiespetrographische Gliederung der quartären Schichten erarbeitet, unter maßgeblicher Mitwirkung von Frau Dipl.-Geol. C. KABEL (in Duphorn 1980, 1983). Von Gorleben aus wird der Verlauf der Niederterrasse anhand von 11 Querprofilen bis in die Deutsche Bucht verfolgt.

Die mittelpleistozäne Flußentwicklung im nordöstlichen Harzvorland: Petrographie, Terrassenstratigraphie

The present study deals with the evolution of the middle Pleistocene river system in the north-eastern foreland of the Harz Mtns. Sediments of the middle fluvial terrace level (early Saalian time) are the main objectives. By using these sediments supplementary with some results of upper fluvial terrace level (early Elesterian time or older) the fluvial palaeogeography within the area has been reconstructed. The sediments were investigated with respect to their gravel spectra, heavy mineral record, sedimentary structures and altitude above the recent river beds. Due to the resulting specifics the sediments have been attributed to particular rivers in the area. Furthermore it is possible to distinguish between fluvial sediments and Elsterian as well as Saalian fluvioglacial deposits. Together with discernible middle or upper terrace characteristics this led to a spatio-temporal reconstruction of the palaeo river system of the Harz Mtns. It revealed that not only during upper terrace sedimentation but even while middle terraces were deposited the rivers partly diversed. These river diversions were mainly caused by hydrodynamic changes reflecting interaction of the fluvial system with Elsterian and Saalian ice shield formation in the north. The Rivers Ecker, Ilse, Rammelsbach, Holtemme, Goldbach, Bode, Selke and Eine were affected by this development as follows: Upper terrace level formation: • The Ecker River formerly ran between its recent river bed and that of the Use River in direction to the Großer Fallstein Mtn. • The Use River flowed to the NE towards the Huy Mtn. • The Goldbach River and the Holtemme River mutually ran to the NW south of the Huy Mtn. After uniting with the Use River and Ecker River it ran south of the Großer Fallstein Mtn. Middle terrace level formation: • The Ecker River flowed far more NE. • Near to the Harz Mtns. the Use River flowed more in the E. The tributary junction of the Rammelsbach River was located far more downstream. Thereafter the Use River ran to the N between Huy Mtn. and Großer Fallstein Mtn. to end up flowing in the area of the Großes Bruch. • The Holtemme River kept its course. Its recent tributary the Goldbach River flowed to the NE and joined the Bode River after leaving the Harz Mtn. Range. • The Eine River ran to the NW when passing todays city of Aschersleben. After flowing together with the Selke River in the area of the Seeländerei it became a tributary to the Bode River. • The Bode River within the recent tributary junction of the Holtemme ran far more in the W. In the area of the Espenbruch it flowed eastwards to the Saale River. The following general implications resulted out of the study: • The so called “mixed sediments” sensu Rosenberger & Altermann (1975) have now been interpreted as proximal fluvioglacial deposits. • High altitudes of middle terrace fluvial deposits in the courses of the Ecker River and Use River were formerly assigned to post middle Pleistocene uplift of the Großer Fallstein Mtn. (Feldmann, 2002). The present study suggests that the unusual high altitudes should rather be attributed to post middle terrace level erosion of the shortened Ilse- Rammelsbach river system or fluvioglacial processes below the glacier. • Within the north-eastern foreland of the Harz Mtns. middle terrace level deposits have previously been subdivided by cryoturbation horizons or short-term progradation of Saalian glaciation. This is not supported by own results for the examined area.

Fluviale sedimentsequenzen im Vorland der Serra dos Órgãos - Indikationen für klimatisch bedingte geomorphologische Instabilitäten im Mittel- und Jungholozän, Bundesstaat Rio de Janeiro/Brasilien.

2011

GEOMORFOLOGIA Y USO DEL SUELO

Se ha pretendido demostrar la importancia de los estudios geomorficos en la planificación del uso del suelo de un área y la manera en que pueden ser afectadas las zonas de expansión urbana por la omisión del factor geomorfológico. El área en Estudio es pequeña, comprende la sección SE de la hoja topográfica Abra, escala 1:50.000, pero se aplico una metodología en la que se hicieron intervenir el análisis de la carta topográfica, de las fotos aéreas y estudios de campo. Se hizo un mapeo de formas y otro de suelos. Se estudió el uso actual del suelo y el uso potencial. ASTRACT The author has attempted to demonstrate the importance of geomorphic studies in the land use planning of an area and the manner in which urban expansion can be affected by the omission of the geomorphologie factor. The small study area covers the southeast section of the Abra topographic map, scale 1:50.000. No matter the size of the study area, a methodology was used that permitted an extensive analysis of the forms and types of landforms encountered. Also studied was the actual and potencial land use of the area.