3. creep- The slow gradual motion of soil/sediment downslope by a combination of gravity and heaving of particles by frost or shrink swell action.

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1 Exam 1 GEOL 407- Geomorphology Name I. Define and describe any 10 of the following terms- Be CONCISE, yet THOROUGH 1. epeirogeny- Regional uplift (and increase in potential energy) with minimal deformation of strata. The geomorphologic response to this endogenic influence is less than with isostatic adjustment or tectonic deformation 2. neap tide- Lower than normal tidal ranges caused by solar and lunar gravitational force vectors pulling on the earth (primarily noticed in oceans) in opposition (90 ) to each other. 3. creep- The slow gradual motion of soil/sediment downslope by a combination of gravity and heaving of particles by frost or shrink swell action. 4. exogenic forces- Forces governing a geomorphic systems response that are external to the system itself, such as epeirogeny, climate or tectonics. 5. eluviation- The vertical transport of fine particles (clay and silt) and dissolved materials away from a given horizon to soil horizons at lower depth. Typically associated with O, A, and E-horizons. 6. wave base- Wave base is defined by the mathematic relationship ½ λ which is the wavelength. It is a controlling factor in determining at what depth sediments can be transported by wave activity shoreward. 7. isostasy- Vertical adjustment of crust, rocks, sediments and water due to density driven buoyancy of crustal materials in relation to denser, underlying mantle material (magma). 8. estuary- An embayment created as a river valley is flooded by a either a eustatic sea level rise or a relative sea level rise. Typically characterized by brackish water conditions as fresh water from the river mixes with sea water. 9. dynamic equilibrium- a balance between driving and resisting forces of change that exists within a range of values for both factors, each of which is systemically stable until some critical threshold of change is achieved. 10. slump- a category of mass wasting in which there is a distinct curved detachment surface along which rotational motion occurs. The rate of movement is variable (from slow to moderately fast) and there is little to no water involved. Durbin GEOL 407, Fall

2 11. ped- a clump of soil that occurs as the result of soil forming processes. They are typically classified on the basis of shape, size and strength. 12. littoral drift- the shore parallel movement of sediments due to longshore currents. 13. intrinsic threshold- a threshold, or circumstance under which no change occurs but above which a systemic change happens, that is internal to the system and is thus very difficult to identify. 14. slide (mass wasting)- Mass wasting that involves very little internal shear motion of the slide mass, and typically occurs at relatively rapid speeds (medium fast to very fast) with varying amounts of water content (may or may not involve water). 15. eustasy- the change in the volume of water in the oceans relative to their basin size. Resulting in either a global sea level rise or a global sea level fall. II. Short Answer- Answer the following questions or perform the following tasks. As before, be thorough, yet concise. 1. Identify four landforms in this East-Northeast looking view of a feature along the coast of Spain in the Mediterranean Sea. Be sure to mark the location of features that you are identifying on the photograph, and be sure to define what the geomorphic features are and how they formed. Durbin GEOL 407, Fall

sand Delta, most likely a birdsfoot delta with significant wave modification. It could also be a wave dominated delta, with a strong influence on the fluvial input from human activity.

3 sand Delta, most likely a birdsfoot delta with significant wave modification. It could also be a wave dominated delta, with a strong influence on the fluvial input from human activity. The delat formed as the river entered the sea, loisng energy as it spread out from the confines of the channel into the sea, and as a result of diminished gradient Recurved spits (2) - one on the north side and one on the south side. These are created by littoral drift of sediment by a bi-directional current generated by waves with distinct and unique approach vectors. Beach- created by waves reworking the materials dumped into the sea by the river along the delta front. Lagoon - an area in the ocean protected from waves by a barrier of some sort with restricted circulation of ocean water. Durbin GEOL 407, Fall

4 2. You are working as a consultant when you are asked to assess the suitability of given location for building a school. Here is the background that you are given: 1) The area is mountainous; 2). The area goes through wet and dry cycles; 3) The area is prone to mild to moderate earthquakes; and 4) The area where the school is to be built is underlain by unconsolidated (non-lithified) sediments. Explain what evidence you would look for to assess the site s safety from geomorphological hazards. Look for precariously balanced features (evidence of when the last earthquake that was large enough to shake loose material for landslides), the shear strength of the underlying material, steepness of slopes, irregular or jumbled terrain, scarps, tilted trees, pistol butt trees, lobate landforms, stair step topography and evidence of tension cracks or fractures in the surface materials that may indicate mass wasting is occurring. Any or all of these of these might indicate that mass wasting has occurred and may occur in the future. Of course not finding any of these things does not guarantee that a mass wasting event or other catastrophic event won t happen. 3. Explain the three ways soils are used in geological investigations. Comment on how they are used in kind of geological investigations. Stratigraphic Correlation tool - As soil develops in the materials that underlie the former land surface, recognition of ancient soils (paleosols) in the rock record can be useful for correlation of strata across geographic barriers and demarcating litho, bio, and allostratigraphic boundaries Durbin GEOL 407, Fall

5 Relative age tool - soils develop over time, so if the four other variables that influence soils formation are accounted for, it is possible to determine the relative age of landforms/surfaces by examining the degree of soil profile development or individual horizon characteristics. Paleoenvironmental tool - because soils are influenced by the environment within which they form, it is possible to reconstruct paleoenvironmental conditions from recognition of the type of soil that formed in the materials 4. Explain how these graphs might be useful in any geomorphological study using soils. Don t forget to comment on what the graphs actually depict, as well as how they could be used. These graphs show the time it takes for specific soil horizons to form, and to achieve a steady state with respect to specific property development, like color, structure or texture (A) and similarly, the time it takes for specific soil orders to achieve steady state as well. This kind of information is useful for establishing the baseline for use of soils as a relative time tool and for relating degrees of soil development between soils of different orders or with different characteristics with respect to their relative ages. It is meant to showcase the independence from environmental conditions. In addition, because of the broad time scale shown for expression of each property and/or soil order, it is not possible to use this as a chronological or absolute age determination, except determination of minimum age necessary to express that specific property or soil order. Durbin GEOL 407, Fall

6 5. There are two schools of thought as to the emphasis of major processes and/or elements in geomorphological research. Identify the schools of thought that were mentioned, who championed the idea, and what elements are emphasized in each paradigm. Davisian Geomorphology- Time is the key element wherein landscapes evolve. One can determine the age of the landscape by the types of landforms observed. In addition, the landscape is capable of being rejuvenated by tectonic forces, basically reworking the existing landscape. Gilbert Geomorphology- the landscape is in dynamic equilibrium with the forces trying to drive change and those trying to resist change. Time is one of many variables that come into play, but is no more or less important than other factors. 6. What are the five factors that influence soil formation and how do the factors influence pedogenesis? A Topography/slope aspect- Slope steepness and orientation with respect to sunlight affect moisture and possible mobility of materials. Materials transported downslope accumulate at lower elevations, and do so faster with stepper slopes. B Climate - moisture and temperature control rates of chemical and mechanical weathering and movement of materials by translocation or dissolution/precipitation. Therefore soil development is affected C Parent material- Mineralogical content influences types of reactions and mechanical processes in operation. For example, parent material rich in quartz would be resistant to chemical and mechanical weathering whereas one rich in calcite would be less resistant chemically and mechanically. Durbin GEOL 407, Fall

7 D Vegetation- veggies act as sediment baffles, contribute chemical compounds, alter minerals, and influence soil by restricting its removal by slope processes. E Time- All other factors held constant or accounted for, time allows for increased development in profile characteristics and soil types. This allows soils to be useful as relative age determination tools. Durbin GEOL 407, Fall

7. Identify the features shown in this slide, explain how they formed, what category of coastline this is, and speculate as to what processes are affecting the coastline now and in the past.

8 7. Identify the features shown in this slide, explain how they formed, what category of coastline this is, and speculate as to what processes are affecting the coastline now and in the past. Wave cut terraces and an emergent coastline are apparent. Wave activity is eroding into the land creating wave cut platforms that when uplifted by mountain building become stranded above sea level and therefore become wave cut terraces. At least 4 episodes of coastal erosion and subsequent uplift are illustrated in this photograph. In addition, there is a headland and an embayment (maybe an estuary) along the active coastal zone. Clearly tectonic forces and coastal forces are at work in creating this landscape. Durbin GEOL 407, Fall

9 8. Perform the following basic tasks using the map provided. Note that the fractional scale given on the map is not accurate given the reduction in size of the map, thus you will have to calculate it using a ruler and your brain. A) Determine the fractional scale of the map. 1:37866 B) Convert the fractional scale to 1 inch = 0.97 km (show your work) C) Use UTM to determine the coordinates of the peak of Blacktail Butte down to the nearest meter E N D) Use Lat Long to determine the coordinates of the peak of Blacktail Butte down to the nearest second N W E) What is the area (in square miles) of section 33? 1 mi 2 Durbin GEOL 407, Fall

10 Durbin GEOL 407, Fall

$Strata dipping into the valley, or fractures that act as slip surfaces gave way during a disruption of equilibrium in the slope.$

11 9. Identify the feature shown here and explain what has happened and what factors are likely involved. This is a landslide of the rock slide/debris flow type. Strata dipping into the valley, or fractures that act as slip surfaces gave way during a disruption of equilibrium in the slope. The equilibrium disruption could have been earthquake related, rainfall related, related to hydrostatic pressure, or oversteepening of the slope by humans or nature processes like stream erosion. It is difficult to ascertain if there is internal shearing or not, but assuming that there was shearing yields the classification mentioned in the introduction statement. Durbin GEOL 407, Fall

12 10. Identify the five agents of change in geomorphology. Cite an example of how each agent acts to influence the landscape development and explain how the agent is involved. Gravity- exerts a vertical force downward on all objects with mass (in the case of Earth s gravitiational force) or toward objects in space (e.g., moon and sun in the case of tidal forces). Drives wave collapse, mass wasting, tidal fluctuations, incision, and many other processes Wind- acts as a fluid and exerts force on the earth surface as air moves over it. Wind causes erosion (deflation basins), deposition (dunes), or features like waves on water surface or saltation in the case of sand particles. Water- moving water exerts forces on the materials over which it flows (causing erosion and deposition according to energy available vs particle size) and contributes to reactions that facilitate chemical and mechanical weathering in the case of soil development Ice- capable of pickup up and transporting huge amounts of sediment and extremely large particles as it flows, it also exerts strong force when it freezes and expands in confined spaces Humans- we move a lot of sediment/rock/water and are frequently responsible for throwing nearly every type of geomorphic system into disequilibrium if it suits our need. Durbin GEOL 407, Fall

Intro to Geomorphology Key Concepts

Intro to Geomorphology Key Concepts Geomorphology Literally means the study of earth landforms - Geo = Earth - Morph=Form - Logos= Study of Involves understanding of - Mineralogy - Structure - Tectonics