Slops
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The document discusses various aspects of slopes and badlands in desert geomorphology. It defines slopes as the angle of the earth's surface relative to horizontal, and describes the key slope processes of erosion, transportation, and deposition driven by geological agents like water, ice, and wind. It outlines different slope types including gentle vs steep, convex, concave, depositional, and tectonic. Badlands are defined as dry terrain with softer sedimentary rocks and clay-rich soils eroded by wind and water, forming steep slopes with minimal vegetation. Mass movement is explained as the gravity-driven movement of surface material, with water playing an important role. Different types of mass movement are also defined such as soil creep, sol
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Slops
- 3. Slopes What is Slopes ? Slope Process Types of Slopes Slope Elements
- 4. What is Slopes ? The angle which any part of the Earth’s surface makes with the horizontal. vertical change horizontal change
- 5. Slopes process Geological agents water icewind + Gravity’s Role • Erosion (weathering) • Transportation ( mass movement ) • Deposition ( Debris slop, Talus cone)
- 6. Types of Slopes 1-Gentle Slopes 2-Steep Slope 3-Convex Slope 4-Concave Slope 5- Depositional Slopes 6-Tectonic Slopes
- 7. Types of Slopes What is the Different between Gentel Slope and Steep Slope? topographical map
- 8. Types of Slopes 1. Gentle Slope A slope with contour lines spread far apart from each other. This even spacing is maintained in both up and down slope. 2. Steep Slope A slope represented with contour lines close to each other on a topographical map. topographical map
- 9. Types of Slopes 3- Convex Slope 4- Concave Slope A slope which becomes progressively steeper downhill A slope which becomes progressively steeper uphill
- 10. 5- Depositional Slopes Deposits of weather material build up to form inclined surfaces, mounds and hills when an agent of erosion (e.g. wind, water or ice) Types of Slopes Examples - alluvial fans - alluvial cones - deltas - -sand dunes.
- 11. 6-Tectonic Slopes These are formed through ”internal forces“ that result in the ) folding, warping and faulting( of rock masses or layers. Anticlines and synclines horsts and graben Types of Slopes
- 12. Slope Elements Crest A small convex-shaped slope, with a thin covering of soil Scarp Cliff A near vertical slope, more than 80° to the horizontal Talus / Scree / Debris A slope with a constant angle, and is formed of eroded material from crest and freeface Knickpoint The change in gradient at the base of the scree slope Pediment A low-angle concave slope
- 14. Knickpoint
- 15. Padiments What is pediments? Processes responsible for carving pediments Formational zones of pediments
- 16. What is pediments? • A pediment is a very gently sloping (5°-7°) • It typically slopes down from the base of a steeper retreating desert cliff, or escarpment, but may continue to exist after the mountain has eroded away. • It is caused by erosion.
- 17. What is pediments? It develops when sheets of running water wash over it in intense rainfall events.
- 18. Three formational zones are recognized for pediments: • An inner most zone of mountainous uplands that have near vertical erosion • An intermediate zone which is the pediment beyond the mountain front. • An outer zone which extends beyond the pediment and is a zone of deposition. Coalescence of pediments over a large area results in a pediplain. formational zones of pediments
- 19. Processes responsible for carving pediments • Erosion by a stream. • Sheet erosion "The removal of thin layers of surface material more or less evenly from an extensive area of gently sloping land, by broad continuous sheets of running water rather than by stream flowing in well defined channels
- 20. •Rill erosion "The development of numerous minute closely spaced channels result • Mountain-front retreating by weathering Processes responsible for carving pediments
- 22. A small, rounded hill, knob, ridge, or mini mountain that rises abruptly from relatively flat surroundings. - Inselbergs are generally erosional remnants. - Often, inselbergs are composed of harder igneous rock (such as granite)that is more resistant to erosion. What is Inselbergs?
- 23. Example Uluru or Ayer's Rock inselberg in Australia. Photo courtesy of Gillian. Steep-sided monument. Western USA, Fall 2005.
- 24. Mass movement What is Mass movement? The importance of Water in mass movement Types of mass movement Triggers of mass movement
- 25. What is Mass movement?
- 26. What is Mass movement? “ is the movement of surface material caused by gravity. Landslides and rockfalls are examples of very sudden movements of this type” Geological agents water icewind + Gravity’s Role
- 27. • The mass must overcome: – Friction- resistance to motion of a body thatkeeps it from moving over another body. – Inertia- tendency of a body to remain at rest until external force is applied Geological agents water icewind + Gravity’s Role What is Mass movement?
- 28. When the gravitational force acting on a slope exceeds its resisting force, slope failure (mass wasting) occurs. The slope material's strength and cohesion and the amount of internal friction between material help maintain the slope's stability and are known collectively as the slope's shear strength. Gravity’s Role
- 29. The steepest angle that a cohesionless slope can maintain without losing its stability is known as its angle of repose. Angle of repose
- 31. The importance of Water in mass movement Water can increase or decrease the stability of a slope depending on the amount present Small amounts of water can strengthen soils because the surface tension of water increases soil cohesion. This allows the soil to resist erosion better than if it were dry If too much water is present the water may act to increase the pore pressure, reducing friction, and accelerating the erosion process and resulting in different types of mass wasting (i.e. mudflows, landslides, etc.)
- 32. Types of mass movement
- 33. Soil Creep Creep is the slow, continuous movement of soil or unconsolidated sediments over extended periods of time. Causes of Soil Creep Creep is caused by repeated freeze- thaw cycles that slowly inch material downslope (during freezing, particles are elevated perpendicular to the slope, but during thaws they fall straight down to a new position lower on the slope). Creep can also be caused by a buildup of pore water that allows material to begin to flow under the influence of gravity. Effects of Soil Creep Creep causes fence posts, utility poles, walls, and other structures to lean over time. Eventually the lean topples the structures and they must be rebuilt. In some cases, creep can be slowed or prevented by installing drainage pipes in soils that drain them and keep pore pressures low.
- 34. Solifluction It is the down slope movement of soil over a permanently frozen subsurface. Solifluction is common on slopes underlain by permafrost (permanently frozen sub – soil).
- 35. Landslides A landslide is a movement of rock or debris down a slope along one or more distinct surfaces. Landslides range in speed from 1 m/day to as much as 300 km/hr.
- 36. Rockfalls Rockfall (free fall of rock) is an extremely rapid process and occurs without warning. Rockfall is typically the result of frost wedging.
- 37. A mudflow or mud flow : is a form of mass wasting involving "very rapid to extremely rapid surging flow"of debris that has become partially or fully liquified by the addition of significant amounts of water to the source material.
- 38. Slumps The sliding of material along a curved surface called a rotational slide or slump. A common cause of slumping is erosion at the base of a slope. For example, coastal storm waves erode cliff bases, removing supporting material. The slump block rotates downward, producing a scarp (cliff) at the top of the slope.
- 39. Triggers of mass movement Soil and regolith remain on a hillslope only while the gravitational forces are unable to overcome the frictional forces keeping the material in place. Factors that reduce the frictional resistance relative to the downslope forces, and thus initiate slope movement, can include: earthquakes increased overburden from structures increased soil moisture reduction of roots holding the soil to bedrock undercutting of the slope by excavation or erosion weathering by frost heave bioturbation
- 40. Badlands What is Badlands ? Composition Formation Example
- 41. Whats is badlands ? Badlands are a type of dry terrain where softer sedimentary rocks and clay-rich soils have been eroded by wind and water. Steep Slopes Minimal Vegetation lack of a substantial regolith high drainage density.
- 42. • They can resemble a terrain of volcanic rock, Canyons, ravines, gullies, buttes, mesas, hoodoos and other such geologic forms are common in badlands. • They are often difficult to navigate by foot. • Badlands often have a spectacular color display from dark black/blue coal stria to bright clays to red scoria.
- 43. Composition Badlands are characterized by their thin to nonexistent regolith layers. The regolith profiles of badlands in arid climates are likely to resemble one another the upper layer (~1–5 cm) is typically composed of silt, shale, and sand The top layer is a sublayer (~5– 10 cm), below which can be found a transitional shard layer (~10–40 cm), formed largely of loose disaggregated shale chips
- 44. Formation The process of deposition describes the accumulation, over time, of layers of mineral material. Different environments. ( such as seas, rivers, or tropical zones, deposit different sorts of clays, silts, and sand.) 47-million year period of deposition which spanned three major geologic periods depositi on Erosio n. National Park, South Dakota, United States
- 45. Example The "Calanchi" of Aliano, in the Italian region of Basilicata
- 46. Thank you
Editor's Notes
- i will talk about Slopes and The parts , types and the process thats happen in slopes
- انسيل بيرغس
- Slope compares the vertical change (the rise) to the horizontal change (the run) when moving from one fixed point to another along the line انقل هورزانتل
- and of cours Slope process refers to the active agents which bring about changes in landforms, for example the impact of falling raindrops (water) or running water (River sources) or (ice) . And we will talk about slopes process with details in “Mass Movment"
- تيكتونيك كنفيكس كنكيف دبزسشنال Origins of primary slopes • Tectonic (fault scarps) • Depositional (volcanoes, glacial moraines, drumlins(?), dunes, alluvial fans, delta foreset, etc.) • Erosional (glacial and riverine valleys, etc.) • Human activity (blasted rock slopes, hydraulic mining, tailings piles, etc)"
- Gentle Slope A slope with contour lines spread far apart from each other. This even spacing is maintained in both up and down slope. 2. Steep Slope A slope represented with contour lines close to each other on a topographical map..
- ١Gentle Slope A slope with contour lines spread far apart from each other. This even spacing is maintained in both up and down slope. 2. Steep Slope A slope represented with contour lines close to each other on a topographical map.
- 1-Convex Slope On a map the contour lines will be spaced closer together with a decline in height above sea-level. 2-Concave Slope . On a map the Contour lines will be spaced closer with an increase in height above sea-level.
- which has lost its energy of moshen, lays down its load in a pretecelar place. Examples - alluvial fans - alluvial cones -deltas -sand dunes.
- anteclians and seenclians , are formed -when layers of rock are folded. horsts and gruben are formed when blocks of land rise or fall in relation to each other when faulting occours.
- As we can see the Slopes Elements in nature
- Knickpoint The change in gradient at the base of the scree slope as we can see in this circle the chang in gradient near of base
- The engle Low angle, It is typically a concave surface gently sloping away from mountainous desert areas. Slope is not uniform- steeper close to the talus slope. Pediment increases as the slope increases backwards due to scarp recession
- It develops when sheets of running water (laminar sheet flows) wash over it in intense rainfall events. It may be thinly covered with fluvial gravel that has washed over it from the foot of mountains produced by cliff retreat erosion. It is typically a concave surface gently sloping away from mountainous desert areas.
- - However, inselbergs may also form in sedimentary rocks.
- How process affects slope morphology mass movement and morphology • creep leads to the development of convex upward slope segments • solifluction, slumps, and flows commonly result in concave upward profiles at their heads and convex toes of colluvium • rock fall forms a talus (scree slope)beneath a free face (cliff) o slope of talus is governed by: ♣ angularity of sediment ♣ Rate of rock fall vs. rate of weathering and erosion of talus o Pediment surfaces that lack significant debris beneath the free face develops because talus is weathered and removed faster than it is produced Effects of water • surface flow (Horton overland flow, or slopewash, and channel flow): o aids the development of concave upward profiles in valleys and o convex upward profiles along divides • subsurface flow (downward percolation, throughflow and groundwater flow) o aids in elluviation (minor?mechanism of slope decline) o aids in the formation of earthflows and solifluction o may lead to surface channel formation by piping (sapping).
- • The mass must overcome: – Friction- resistance to motion of a body that keeps it from moving over another body, and – Inertia- tendency of a body to remain at rest until external force is applied
- When a slope made of loose material possesses this angle, its shear strength perfectly counterbalances the force of gravity acting upon it. Angle of Repose The maximum angle at which slope material can be inclined without moving downslope It is a critical value for stability for a particular slope If the actual slope angle is less than the angle of repose, the slope is stable If the actual slope angle is greater than the angle of repose, mass movement can occur The angle of repose changes as slope conditions (such as soil moisture) changes The angle of repose can never be exceeded Angle of repose can decrease under severe motion (earthquakes) or saturation
- Mass wasting may occur at a very slow rate, particularly in areas that are very dry or those areas that receive sufficient rainfall such that vegetation has stabilized the surface. It may also occur at very high speed, such as in rockslides or landslides, with disastrous consequences, both immediate and delayed, e.g., resulting from the formation of landslide dams. Factors that change the potential of mass wasting include: change in slope angle, weakening of material by weathering, increased water content; changes in vegetation cover, and overloading. Volcano flanks can become over-steep resulting in instability and mass wasting. This is now a recognised part of the growth of all active volcanoes. It is seen on submarine as well as surface volcanoes: Loihi in the Hawaiian volcanic chain and Kick 'em Jenny in the Caribbean volcanic arc are two submarine volcanoes that are known to undergo mass wasting. The failure of the northern flank of Mount St Helens in 1980 showed how rapidly volcanic flanks can deform and fail.
- . A good example of this is to think of a sand castle. Water must be mixed with sand in order for the castle to keep its shape. If too much water is added the sand washes away, if not enough water is added the sand falls and cannot keep its shape. Water also increases the mass of the soil, this is important because an increase in mass means that there will be an increase in velocity if mass wasting is triggered. Saturated water, however, eases the process of mass wasting in that the rock and soil debris are easily washed down-slope
- ypes of mass wasting Based on how the soil, regolith or rock moves downslope as a whole, mass movements can be broadly classified as Slow Movements, Rapid Movements and Landslides. Creeps[edit] Soil creep is a long term process (slow movements). The combination of small movements of soil or rock in different directions over time are directed by gravity gradually downslope. The steeper the slope, the faster the creep. The creep makes trees and shrubs curve to maintain their perpendicularity, and they can trigger landslides if they lose their root footing. The surface soil can migrate under the influence of cycles of freezing and thawing, or hot and cold temperatures, inching its way towards the bottom of the slope forming terracettes. This happens at a rate that is not noticeable to the naked eye. Landslides[edit] A landslide, also called a landslip, is a rapid movement of a large mass of earth and rocks down a hill or a mountainside. Little or no flowage of the materials occurs on a given slope until heavy rain and resultant lubrication by the same rainwater facilitate the movement of the materials, causing a landslide to occur. The common forms of landslides are slump, debris slide, rock slide, rock fall, debris fall and avalanche. Flows[edit] See also Landslide classification § Flows. Movement of soil and regolith that more resembles fluid behavior is called a flow. These include avalanches, mudflows, debris flows, earth flow, lahars and sturzstroms. Water, air and ice are often involved in enabling fluidlike motion of the material. Slump[edit] A slipping of coherent rock material along the curved surface of a decline. Slumps involve a mass of soil or other material sliding along a curved surface (shaped like a spoon). It forms a small, crescent-shaped cliff, or abrupt scarp at the top end of the slope. There can be more than one scarp down the slope. Falls[edit] A fall, including rockfall, occurs where regolith cascades down a slope, but is not of sufficient volume or viscosity to behave as a flow. Falls are promoted in rocks which are characterised by presence of vertical cracks. Falls can result from undercutting by running water as well as from undercutting by waves. They usually occur at very steep slopes such as a cliff face. The rock material may be loosened by earthquakes, rain, plant-root wedging, and expanding ice, among other things. The accumulation of rock material that has fallen and resides at the base of the structure is known as talus . . Types of Mass Movements Rockfall Loose rocks fall through the air, accumulate in a talus cone High angle of repose Debris avalanche Rocks, debris and soil Extremely high velocity Water and ice often fluidize debris Landslide Unsaturated mass of bedrock and regolith that moves suddenly and rapidly Rotational slumping Translational slides Flows earthflow mudflow Creep: a persistent movement of soil down slope . 9. Rockfall . 10. Rotational block slump . 11. Debris avalanche . 12. Debris avalanche . 13. Soil Creep
- During the summer when the upper permafrost is activated, the waterlogged soil mass slowly moves down slope to form solifluction lobes or terraces.
- Frost wedging is a process where water enters cracks in rocks, freezes, expands, and breaks the rock apart.
- تريجلز
- They are characterized by steep slopes, minimal vegetation, lack of a substantial regolith, and high drainage density. Draneg
- ريجليث سيلت – شيل – Desagregated Some badlands have no regolith layer whatsoever, capping instead in bare rock such as sandstone. Others have a regolith with a clay veneer, and still others have a biological crut of algae or lichens. n addition to lacking significant regolith, they also lack much vegetation. The lack of vegetation could very well be a result of the lack of a substantial regolith.[3]
- The formation of badlands is a result of two processes: deposition and erosion. The process of deposition describes the accumulation, over time, of layers of mineral material. Different environments. ( such as seas, rivers, or tropical zones, deposit different sorts of clays, silts, and sand.)For instance, the badlands formations in Badlands National Park, South Dakota, United States underwent a 47-million year period of deposition which spanned three major geologic periods (the Cretaceous Period, the Late Eocene, and the Oligocene Epochs), resulting in clear, distinct layers of sediment[4] which serve as a dramatic display of the law of superposition. Once the deposited sediments have solidified, the sedimentary material becomes subject to erosion. It is sometimes erroneously taught that badlands erode at a steady rate of about one inch per year.[5] In actuality, the precise processes by which the erosion responses take place vary depending on the precise interbedding of the sedimentary material.[6] In 2010, researchers at Badlands National Park initiated a three-year project to learn more about the actual erosion rate of the specific badlands found in that park.[5]
- Some of the best-known badland formations can be found in Canada and the United States. In the U.S., Makoshika State Park in Montana and Badlands National Park in South Dakota together form a series of extensive badland formations. Among the Henry Mountains area, about 1500m above sea level, Cretaceous and Jurassic aged shales are exposed. Theodore Roosevelt National Park is a United States National Park composed of three geographically separated areas of badlands in western North Dakota and was named for U.S. President Theodore Roosevelt. Another popular area of badland formations is Toadstool Geologic Park in the Oglala National Grassland of northwestern Nebraska. Dinosaur National Monument in Colorado and Utah are also badlands settings. A small badland called Hell's Half-Acre is present in Natrona County, Wyoming. Additional badlands also exist in various places throughout southwest Wyoming, such as near Pinedale and in the Bridger Valley near the towns of Lyman and Mountain View, near the high Uintah Mountains El Malpais National Monument in western New Mexico is named after the Spanish word malpaís, meaning bad lands. The Big Muddy Badlands in Saskatchewan, Canada, gained notoriety as a hideout for outlaws. There is a large badland area in Alberta, Canada, particularly in the valley of the Red Deer River, where Dinosaur Provincial Park is located, as well as in Drumheller, where The Royal Tyrrell Museum of Palaeontology is located. The "Calanchi" of Aliano, in the Italian region of Basilicata A well-known badlands formation in New Zealand – the Putangirua Pinnacles, formed by the erosion of the conglomerate of an old alluvial fan – is located at the head of a small valley near the southern tip of the North Island. Other badlands can be found in Italy, known as "Calanchi". Some examples include Aliano, Basilicata, and Val d'Orcia, Tuscany. The Bardenas Reales near Tudela, Navarre, and the Tabernas Desert in Tabernas, Almería, and possible Los Monegros in Aragon, all of them in Spain, are examples in Europe. The Valle de la Luna ("Valley of the Moon") is one of many examples of badland formations in midwestern Argentina. This geologic formation is the only place in the world where nearly all of the Triassic is represented in an undisturbed sequence of rock deposits. The badlands of the Gutingkeng Formation in southern Taiwan are the only example of badlands in a tropical climate. The formation has a thickness of 3–4 km and covers over 100,000 hectares.[citation needed] Although most badland scenery is natural, there are some examples produced by mining, such as the Roman gold mine of Las Médulas in northern Spain. An example of badlands produced by poor farming practices is the Cheltenham Badlands in Caledon, Ontario.