Stratigraphy can be considered as the relationship between rocks and time The euhedral morphology can be a good clue, but identification of dolomite 3 GL A C I E R S In high mountain areas small cirque glaciers (Fig. dinosaurs to the burrows and nests of insects such as beetles, bees and ants (Hasiotis ). The hypothesis results from geomorphologic research of the area based on aspect of slope, shading of relief, longitudinal and cross section, degree of cirque deepening), .. the relief glacial modelling has been signiﬁcantly more intensive Cirque overdeepening and their relationship to morphometry. In Atlas of Arthropod Sensory Receptors: Dynamic Morphology in Relation to troglobitic species of wasps or bees (Hymenoptera) are known but many nest produce overdeepened (closed) cirques that may function in a similar way to dolines closed depressions may occupy tectonic structures, or may occupy cirque.
Snow avalanches are met with great interest among the population of Switzerland, since snow sport activities are very popular. However, there is also a tragic aspect, because most of the 25 avalanche victims per year are the ones who cause the slab avalanches in which they lose their lives.
What makes dealing with avalanches so difficult is the fact that they exhibit numerous characteristics of dynamic systems such as openness, non-linearity, emergence, self-organised criticality, and limited predictability.
But in contrast to comparable phenomena such as earthquakes, one individual can interact directly, especially in case of slab avalanches. While this circumstance makes avalanches dangerous, it also makes them particularly interesting for researching systems thinking.
Within the scope of a quasi-experimental study, including pre- and post-tests, the demand for the construction of a learning environment in order to effectively improve the competence of systems thinking about the topic of avalanches was the central goal.
Therefore a teaching unit on the topic of avalanches, consisting of eight lessons, was initially developed as an intervention tool. Examples of such approaches introduced in greater detail in the presentation include an avalanche experiment with everyday materials such as f lour and salt and a computer programme for simulating avalanches Harvey A total of students to year-old in 30 classes participated, with 4 classes serving as the control group.
A standardised questionnaire was used to collect variables such as subject knowledge and everyday ideas of avalanches as well as system competence for the topic of avalanches. The tool to measure the subject knowledge and everyday ideas was taken and adapted from a pilot study Rempf ler a, b.
To operationalise system competence i. The results show that the everyday ideas of avalanches mental models immediately after the treatment are highly significant more differentiated than at time T1 and that this level remains high even after 6 to 8 weeks. In comparison, the control group shows no change or even a negative change. The trend for the system competence and subject knowledge of the students is similar, although somewhat less distinct.
Based on these results the question what elements of the intervention tool could have made a material contribution to changing the mental models and system competence will be discussed. Related and more fundamentally, the question arises what general conclusions for effectively promoting systems thinking can be derived.
Systems Concepts of Youths: System Competence in Geography Education. Es wird untersucht, welche Aspekte in welcher Form Einf luss auf die Kompetenzentwicklung haben. Schuljahres n und in sechs Klassen des 6.
Schuljahres n im Rahmen der Querschnittuntersuchung eingesetzt. Eine Sequenz wurde in Kleingruppen im Realraum absolviert. Schuljahres n begonnen Zeitpunkt 1 Anfang des 3. Schuljahres, gleichzeitig auch Querschnittuntersuchung 3. SchuljahrZeitpunkt 2 Ende des 4.
Zeitpunkt Ende des 6. Im Vortrag werden insbesondere Fragen der Kompetenzmodellierung, methodologische Aspekte des Untersuchungsdesigns vorgestellt und zur Diskussion unterbreitet. Educational Research on Geoscience Teaching and Learning 8 1.
Initial developing of common basics would be time consuming and an important ingredient of the geographical competence would be missing anyway: This being aware that far less geographic scientific theory may be imparted to the students, but based on repeated experience, that sustainable interest on geoscientific topics may be supported this way. All photos and figures are originally made by the students or by me.
Both projects include extended field trips completing thematically the teaching in the classroom. Geology project with a field trip of two days. The initial instruction takes ca. The last field trip, which will be reported here, was carried out in the Albulapass area. Interdisciplinary project in surveying and mapping, in collaboration with mathematics.
Surveying is usually carried out on demand of a local authority, so the students know that their project is useful and will contribute to sustainable development of a municipality. It takes usually 1.
Wir hatten die Aufgabe, die Doline zu vermessen. Um die Tiefe der Doline zu bestimmen, spannten wir ein Seil von oben bis unten. Aus diesen Profilen konnten wir die tiefste Stelle in der Doline errechnen. Unsere genaue Vermessung wird in Zukunft sehr wichtig sein, um festzustellen, ob sich der Boden noch weiter bewegt. Unsere Gruppe war motiviert und ehrgeizig.
Educational Research on Geoscience Teaching and Learning 10 1. However, prior research has indicated that students of all ages show little understanding of hydrological processes e. Based on the principles of constructivist learning theory and conceptual change theory e.
Vosniadou, we developed a learning environment aimed at deep understanding and mental model building of the hillslope spring concept. The following research questions were addressed: During an instructional session, which took 60 minutes, two students, working in pairs, were guided through the learning process by a tutor. The students worked with worksheets, experiments and two physical models of freshwater springs.
After the instructional session they were questioned about their learning difficulties in a one-on-one tutoring interview with each learner. The entire session was videotaped. Following the different steps of qualitative content analysis Mayring,the video and interview transcripts, the drawings and texts were interpreted, systematically categorized, generalized and contrasted.
The analysis of the learning pathways showed that the pre-instructional knowledge had the most significant inf luence on mental model building and conceptual change. Their conceptual change concerned the change or adaption of their pre-instructional cognitive schemata. Students who showed elaborated but false mental models that were based on personal experiences with freshwater springs showed great difficulties in changing their personal mental models and adapting them to the scientific model.
Apparently, their initial but false mental models, constructed through real world experience in social contexts and thus emotionally charged offered a greater subjective plausibility to them than did our teaching materials. Even if an appropriate, theory-based and effective learning environment is available to teach a certain topic, teaching for deep understanding involves: If instructors learn how to make use of mental model evolution strategies, their teaching for meaningful conceptual change will be more effective.
Hydrology and Earth System Science, 16, International Handbook of Research on Conceptual. As one part of the project, seismic stations are installed at schools and used to record real-time seismic activity. These stations meet, to a large extent, the technical standards of the national seismological monitoring networks operated by the Swiss Seismological Service SED.
Earthquake databases for classroom use are generated by compounding event data recorded at the school stations with data from broadband stations of the national network, and, for large global events, also with data from global scientific and school seismic networks. The installation of seismic stations in schools, and further operation of the stations by the schools, requires dedicated involvement and training of teachers.
Full text of "Essays In Geomorphology"
This is achieved by working directly with the involved teachers at schools in the form of workshops, and by offering seminar days at ETH Zurich in collaboration with the focusTerra earth science information center www.
As a second part of the project, educational materials and concepts are developed in close collaboration with involved teachers, which can be used by all schools, irrespectively of whether they host a seismic station. Having been launched inthe Seismo at School network today involves eight schools with their own seismic station, with the aim of installing a total of 26 stations in as many schools over the next years.
Seismo at School is also integrated in European and global school seismology activities and actively engages in collaborations to develop new materials, exchange data, and to foster connections among participating schools.
Sie bezeichnen die Jahreszeiten, die das Jahr bei uns in verschiedene Perioden unterteilen. An den Polen unterscheidet man nur das Sommer- und das Winterhalbjahr; innerhalb der tropischen Zone findet man hingegen nur Trocken- und Regenzeiten. Im Rahmen meiner Geographielehrerausbildung habe ich das Thema von Fehlvorstellungen im Geographieuntericht am Beispiel von Jahreszeiten untersucht.
Das Ziel war es eine Unterrichtstrategie zu entwickeln, die die Fehlvorstellungen zum Thema Jahreszeiten abbauen kann. Basierend auf der 4-Phasen Strategie von S. Unterrichtsmaterialien im Umfeld der Sekundarstufe: Geographie Heute Designing learning environments to promote conceptual change in science. Learning and Instruction 11, Structural Geology, Tectonics and Geodynamics 14 2.
Thermo-mechanical model for the finite strain distribution in kilometer-scale shear zonez 2. Early Mesozoic rift-related sandstones of the Southern Alpine Tethys margin characterised by detrital zircons: U-Pb dating and Hf-isotopes analysis 2. Tunisia, southern Tethyan passive marge 2. Oblique normal faulting in carbonates at different crustal levels: Self-consistent modelling of planetary differentiation and onset of mantle convection on Mars.
A comparative study in 2D and 3D 2. Tectono-magmatic crustal convection produces novae and coronae on Venus 2. Structure and evolution of the Central Andes of Peru 2. A long-lived, multiphase structure in the North Alpine Foreland - Insights from high-resolution 3D seismic data 2.
Thick-skinned tectonics in the Alpine foreland of central northern Switzerland: New perspectives based on reprocessed and new ref lection seismic data 2. Towards 4D modeling of transpressional fold-and-thrust belts 2. Alpine fold and thrust structures: Coupling of landscape evolution and rheologically layered thermomechanical models in three dimensions 2. Determination of strain rates from GNSS campaign and levelling data 2. Deformational evolution of the Aar Massif Central Alps: From macro- to micro-scale 2.
Dynamic recrystallization and shear heating in numerical models of lithospheric-scale shear zones P 2. Dynamic origin of Wilson cycles in mantle convection with self-consistent plate tectonics and continental drift P 2.
Implications of single-sided subduction in global selfconsistent models of mantle convection P 2. Towards combined modelling of planetary accretion and differentiation P 2. Theory and Applications P 2. Do foliation refraction patterns around buckle folds represent finite strain? Modeling interactions between tectonic and surface processes in the Zagros Mountain, Iran P 2.
Cenozoic deformation of Mount Birk: A key to restoring of Iranian Baluchestan tectonic history P 2. Sandstone detrital mode and heavy mineral study in the Makran accretionary wedge, southeast Iran: The breccias of Sambosan Accretionary Complex southwestern Japan: Investigation of deep geological structures in the north-west part of Canton of Neuchatel using a combination of gravity and 3D geological model P 2.
New insights from balanced cross sections and 3D modelling P 2. To what extent have inherited normal faults inf luenced thrust propagation at the front of the easternmost Jura fold-and-thrust belt? Structural Geology, Tectonics and Geodynamics 15 Symposium 2: Structural Geology, Tectonics and Geodynamics 16 P 2.
Cross-correlation and location error assessment of nano-earthquakes on the Fribourg Lineament - Switzerland P 2. The application of titanium-in-quartz geothermometry in recrystallized quartz - a methodological discussion P 2. Role of brittle deformation and f luid-rock interaction on the formation of ductile shear zone under blueschist facies conditions P 2. Transient Temperature and Pressure variations in crustal shear zones — numerical modelling using local-thermodynamic equilibrium and a conservative approach P 2.
Chemical zoning and ductility of natural garnet at lower crustal conditions: An example from the Rhodope Massif P 2. Fission-track constraints on the thermal evolution of the Serbo-Macedonian Massif south Serbia, southwest Bulgaria and east Macedonia P 2. The Eastern Pelagonian metamorphic core complex: Chambi Atlas central tunisien. Basement lithostratigraphy of the Adula nappe: Seismic properties and anisotropy in melt-generating metapelites P 2. AlpArray — the next generation seismology initiative P 2.
Deformation of f lat areas by using InSAR. We then derive the analytical solution of the ellipticity of strain ellipses along the shear zone. We thus determine the parameters that provide the best fit between sets of strain ellipses measured in natural kilometer scale shear zones and our model Figure 1. Our simple 1D analytical solution can predict the nonlinear distribution of finite strain across natural kilometer-scale shear zones as a function of temperature and rheological parameters.
Our results for several kilometer-scale shear zones worldwide suggest that temperature increase across shear zones controls to first order the observed nonlinear increase of finite strain towards the base of the shear zone.
In the lowermost tens of meters natural shear zones often exhibit a stronger increase of finite strain often expressed by mylonitic texture than predicted by our simple model. This deviation from our model is likely caused by processes not considered in the model, such as for example, grain-size reduction, effects of f luids or viscous shear heating.
Structural Geology, Tectonics and Geodynamics 17 Symposium 2: Structural Geology, Tectonics and Geodynamics 18 Figure 1. Strain ellipses have been calculated by deforming small initial circles, which have been scaled up, with the analytical velocity profile.
Insights from the External Hellenides: Journal of Structural Geology, v. We present results from: Thus, the Fuorn Fm was mainly sourced in Permian igneous rocks and volcaniclastics, which obviously were exhumed and eroded at the SMAT during the Triassic. Schaltegger and Brack suggest that Permian magmatism and associated basin formation occurred during major post-Variscan extensional and strike-slip movements between ca - Ma, which is in line with our results.
U-Pb ages of detrital zircons from Saluver Fm have a dominant population from ca to Ma with a peak at ca Ma and other minor populations from - Ma and from 1 - 0. The present Saluver Fm sandstone was mainly sourced in Variscan and post-Variscan magmatic and volcaniclastic rocks, whereas no Triassic magmatic rocks were exposed in the source areas.
Detrital zircons from the volcaniclastic layer Ducan-I show a U-Pb age spectrum spanning from to Ma with a peak at ca Ma. The U-Pb ages of detrital zircons from the second volcaniclastic layer Ducan-II shows a range from to Ma with a peak at ca Ma. The differences of the measured Hf - isotope ratios between these two volcaniclastic layers can be explained by two scenarios: The younger age spectrum Ma correlates with other Ladinian and Carnian volcanic and volcaniclastic formations in the Austroalpine domain.
The epsilon-Hf values -6 to -3 suggest a mantle source highly mixed with crustal material. There are contrasting models proposed to explain the Triassic Alpine magmatism, either within an extensional environment e. The results from Triassic detrital zircons corroborate the model of Crisci et al.
These authors suggest the origin of the magmas through partial melting of an upper mantle, which was deeply modified during the previous Variscan orogeny. The rising melts included crustal material during early stages of rifting along the SMAT. The Middle Triassic magmatic-tectonic arc development in the Southern Alps. Geologische Rundschau, 73, U-Pb zircon age of volcaniclastic layers in Middle Triassic platform carbonates of the Austroalpine Silvretta nappe Switzerland.
The project is supported by the ETH Zurich internal grant no. The results allow us to reconstruct the movements of the Triassic salt during its Early Mesozoic history. The extrusion rate may have exceeded 55mm year-1 and the salt fountain reached higher than m in the Early Cretaceous sea if its vent was then narrower than its current maximum width.
PhD Thesis, Tunis Univ. Age, budjet and dynamics of an active salt extrusion in Iran. Journal of structural geology 6, Structural Geology, Tectonics and Geodynamics 19 Symposium 2: Structural Geology, Tectonics and Geodynamics 20 2.
In order to provide constraints on the processes involved in fault slip accumulation on oblique normal faults, the current study describes the fault architecture in field exposure of such faults exhumed from different crustal levels. Fault length kmaccumulated displacement km and lithology carbonate rich passive margin sequences are comparable for the examples from the SW Helvetics and the Gran Sasso Central Apennines.
Session Advances in applied hydrology and limnology
However faults from the SW Helvetics show an interplay between brittle and ductile structures whereas those from Gran Sasso were entirely brittle during seismic faulting.
Most large crustal earthquakes are triggered on faults at the brittle-ductile transition, which in the continental crust commonly occurs in sedimentary rocks buried to depths of 8 to 13 km, depending on the geothermal gradient and the tectonic regime in particular, whether faults are dominantly normal, thrust or strike-slip.
Potash feldspars such as orthoclase are the most common as grains in sedimentary rocks. It can be difficult to distinguish orthoclase from quartz at first glance because the two minerals have a similar relief and low birefringence colours, but the feldspar will show a cleavage in some orientations, twinning may be seen under cross-polars, and it is often slightly cloudy under plane-polarised light.
The cloudiness is due to chemical alteration of the feldspar, something that is not seen in quartz. Another mineral in this group is microcline, which is noteworthy because, under plane-polarised light, it shows a very distinctive cross-hatch pattern of fine, black and white stripes perpendicular to each other: Plagioclase feldspars are a family of minerals that have varying proportions of sodium and calcium in 18 Terrigenous Clastic Sediments: Gravel, Sand and Mud their composition: The most characteristic distinguishing feature is the occurrence of multiple twins, which give the grains a very pronounced black and white striped appearance under crossed polars.
Micas There are many varieties of mica, but two of the most frequently encountered forms are the white mica, muscovite, and the brown mica, biotite. Micas are phyllosilicates, that is, they have a crystal structure of thin sheets, and have a very well developed platy cleavage that causes the crystals to break up into very thin grains. If the platy grains lie parallel to the plane of the thin-section, they will appear hexagonal, but it is much more common to encounter grains that have been cut oblique to this and therefore show the cleavage very clearly in thin-section.
The grains also appear elongate and may be bent: Biotite is usually very distinctive because of its shape, cleavage, brown colour and pleochroism which may not always be present. It has bright, first-order birefringence colours, but these are often masked by the brown mineral colour: The strong, bright birefringence colours of muscovite flakes are very striking under cross-polars, which along with the elongate shape and cleavage make this a distinctive mineral.
Other silicate minerals In comparison to igneous rocks, sedimentary rocks contain a much smaller range of silicate minerals as common components. Whereas minerals belonging to the amphibole, pyroxene and olivine groups are essential minerals in igneous rocks of intermediate to mafic composition i.
Olivine, so common in gabbros and basalts, is very rare as a detrital grain in a sandstone. Glauconite This distinctive green mineral is unusual because, unlike other silicates, it does not originate from igneous or metamorphic sources. It forms in sediment on the sea floor and can accumulate to form significant proportions of some shallow marine deposits Under plane-polarised light glauconite grains have a distinctive, strong green colour that is patchy and uneven over the area of the grain: Carbonate minerals The most common minerals in this group are the calcium carbonates, calcite and aragonite, while dolomite a magnesium—calcium carbonate and siderite iron carbonate are also frequently encountered in sedimentary rocks.
Calcium carbonate minerals are extremely common in sedimentary rocks, being the main constituents of limestone. Calcite and aragonite are indistinguishable in thin-section: Birefringence colours are pale, highorder greens and pinks. The form of calcite in a sedimentary rock varies considerably because much of it has a biogenic origin: Most dolomite is a diagenetic product When individual crystals can be seen they have a distinctive euhedral rhombic shape, and cleavage planes parallel to the crystal faces may be evident.
The euhedral morphology can be a good clue, but identification of dolomite cannot be confirmed without chemical tests on the material 3. Siderite is very difficult to distinguish from calcite because most of its optical properties are identical. The best clue is often a slight yellow or brownish tinge to the grain, which is a Sand and Sandstone result of alteration of some of the iron to oxides and hydroxides.
Oxides and sulphides The vast majority of natural oxide and sulphide minerals are opaque, and simply appear as black grains under plane-polarised light. The iron oxide haematite is particularly common, occurring as particles that range down to a fine dust around the edges of grains and scattered in the matrix.
The edges of haematite grains will often look brownish-red. Magnetite, also an iron oxide, occurs as a minor component of many igneous rocks and is quite distinctive because it occurs as euhedral, bipyramidal crystals, which appear as four or eight-sided, equant black grains in thin-section. Iron hydroxides, limonite and goethite, which are yellowish brown in hand specimen, appear to have brown edges in thin-section.
Sedimentology and stratigraphy
Pyrite is an iron sulphide that may crystallise within sediments. Although a metallic gold colour as a fully-formed crystal, fine particles of pyrite appear black, and in thin-section this mineral often appears as black specks, with the larger crystals showing the cubic crystal shape of the mineral. Locally, other sulphides and oxides can be present, for example the tin ore, cassiterite, which occurs as a placer mineral minerals that concentrate at the bottom of a flow due to their higher density.
Heavy minerals A thin-section of a sandstone is unlikely to contain many heavy mineral grains. Zircon is the most frequently encountered member of this group: Grains are equant to elongate, colourless and easily recognised by their very high relief: Other relatively common heavy minerals are rutile, apatite, tourmaline and sphene.
The bedrock must itself be composed of crystals or particles that are smaller than sand-size: Lithic fragments of fine-grained metamorphic and sedimentary rocks can also be common.
Chert and chalcedony Under plane-polarised light, chert 3. The difference is that the silica in chert is in an amorphous or microcrystalline form: Chalcedony is also a form of silica that can readily be identified in thin-section because it has a radial structure when viewed under cross-polars; fine black and white lines radiate from the centre, becoming lighter and darker as the grain is rotated.
Organic material Carbonaceous material, the remains of plants, is brown in colour, varying from black and opaque to translucent reddish brown in thin-section.
The paler grains can resemble a mineral, but are always black under cross-polars. The shape and size is extremely variable and some material may appear fibrous. Coal is a sedimentary rock made up largely of organic material: Very fine particles of clay and iron oxide in a lithic fragment will make it appear brownish in thin-section, and if the grain is made entirely of clay it may be dark brown. Siltstone is most commonly composed of quartz grains, which will be evident as black and white spots under crossed polars: Gravel, Sand and Mud Igneous rock fragments Fragments of fine-grained igneous rocks can occur as grains in a sandstone, especially in areas of deposition close to volcanic activity.
Dark grains in hand specimens can be revealed by the microscope to contain tiny laths of pale feldspar crystals in a finer groundmass that appears dark under cross-polars and can be recognised as pieces of basalt.
Basalt weathers readily, breaking down to clays and iron oxides, and these particles will give a brown, rusty rim to any grains that have been exposed for any length of time. With more extensive weathering, fine-grained igneous rocks will break down to clays 2.
Metamorphic rock fragments Slates and fine-grained schists may be incorporated into sandstones if a metamorphic terrain is eroded. These rocks have a strong fabric, and break up into platy fragments that can be recognised by their shape as grains.
This fabric also gives a pronounced alignment to the fine crystals that make up the grain, and this can be seen both in plane-polarised light and under crossed polars. Micas are common metamorphic minerals e. It can be difficult to determine the mineralogy of individual silt particles because of their small size, but they are commonly grains of quartz that will appear as black or white specks under crossed polars.
Tiny flakes of mica or other phyllosilicate minerals may also be present in this size fraction, and their bright birefringence colours may be recognisable despite the small size of the laths. Clay-sized grains are too small to be identified individually with an optical microscope. Under plane-polarised light patches of clay minerals forming a matrix usually appear as amorphous masses of brownish colour.
Under crossed polars the clays turn dark, but often the area of clay material appears very finely speckled as light passes through individual grains. Analysis of the clay content of a matrix requires other techniques such as X-ray diffraction analysis 2. A cement is precipitated out of fluids as part of the post-depositional history of the sediment.
It will normally be crystalline material that fills, or partly fills, the gaps between the grains. The formation of cements and their varieties are considered in section The rock might not be uniform in other ways, with a patchy distribution of grain sizes and types.
Such features should be noted and compared to the hand specimen the thin-section has been cut from.Formation of Glaciers By Kinetech dubaiairporthotel.info
It is always best to start by looking at the slide using low magnification and under plane-polarised light. Lithic fragments and mineral grains can often be best distinguished from each other at this point, and certain distinctive, coloured minerals such as biotite and glauconite recognised.
Individual grains can then be selected for investigation, and their mineral or lithological composition determined using the techniques described above.
Once a few different grain types have been identified it is usually possible to scan the rest of the slide to see whether other clasts are more of the same or are different.
For each clast type the following are then recorded: The nature and proportion of the matrix must also be determined, and also the character and proportion of any cement that is present. Point counting To make a quantitative analysis of the components of a sedimentary rock some form of systematic determination of the proportions of the different clast types, matrix and cement is required. The commonest technique is to attach a point counting mechanism on to the stage of the microscope: It is attached to a mechanical counter or to a computer such that each time a button or key is pressed, the slide moves sideways.
The operator determines the clast type under the cross-wires at each step by pressing different buttons or keys. A series of transects across the slide is made until a sufficient number of points have been counted — typically not less than The size of the step, the magnification used and the number of categories of clast will be determined by the operator at the outset, depending on the grain-size range and clast types recognised in a preliminary examination of the thin-section.
The grain size is generally too small for optical techniques of mineral determination and until scanning electron microscopes and X-ray diffraction analysis techniques 2. In the field mudrocks do not often show the clear sedimentary and biogenic structures seen in coarser clastic rocks and limestone. Exposure is commonly poor because they do not generally form steep cliffs and soils support vegetation that covers the outcrop.
This group of sediments therefore tends to be overlooked but, as will be seen in later sections concerning depositional environments and stratigraphy, they can provide as much information as any other sedimentary rock type.