620 likes | 647 Views
Feat of strength?. THE BLARNEY STONE Derived from the “Scone of Stone” used in coronation ceremonies of Scottish Kings
E N D
THE BLARNEY STONE Derived from the “Scone of Stone” used in coronation ceremonies of Scottish Kings Given as gift by Robert the Bruce – “BRAVEHEART” According to legend, kissing the stone endows the kisser with the gift of gab(great eloquence or skill at flattery).
GRADATION 3 stages? Weathering - Transportation - Deposition
Denundation Breaking down of rock via physical & chemical processes Weathering (in place) Degradation Gradation Erosion(transportation) Aggradation Process that builds up the Earth’s surface through deposition of material Breaking down & removal of rock Resultsin levelling the land to: BASE LEVEL Bill Nye Intro Video Clip
Physical (mechanical) Weathering • More prominent in ___________ regions arid,cold • No change in chemical composition--just …..?
Increases the exposed surface area of rock, making it more vulnerable to further physical and chemical weathering Reduces rock material to smaller fragments that are easier to transport Joint-block separation and granular disintegration are two common forms of bedrock disintegration.
Rates of weathering Joints _______ in a rock are a pathway for water – they can enhance mechanical weathering
Rock breakdown caused by expansion of ice in cracks and joints is called: Frost wedging
Physical Weathering Ice crystal growth within the joint planes of rock can cause the rock to split apart because ice expands by _____? 10%
Name of feature? Talus or scree slope
Shattered rocks are common in cold and alpine environments where repeated freeze-thaw cycles gradually pry rocks apart.
2 adjectives to describe the landscape? jagged rough sharp edges shattered
Type of weathering? Crystal growth What happens to the water? Evaporation occurs
Salt Formation Areas • Coastal regions. • Arid regions. • Urban areas. • Along highways.
Physical Weathering Exfoliation (Pressure Release; Unloading) When overlying material is removed, the pressures on underlying layers of rock lessen. = Expansion Consequently, rocks exposed at the surface may break apart Eg. Retreating ice sheets
Physical WeatheringExfoliation – Pressure Release This granite outcrop in Yosemite National Park, California, displays sheetlike joints, giving a stepped appearance to the mountain slope.
Weathering due to the extreme range of temperatures (can shatter rocks in desert environments.) is called? Thermal Expansion Repeated swelling and shrinking of minerals with different expansion rates will also shatter rocks. Weathering
Physical Weathering Human, animal, vegetable
Periglacial landscapes (Physical Weathering)
blockfields surfaces covered by rock rubble derived largely from weathering of the underlying but largely hidden bedrock
Frost Heaving -heavy dense cold air • Groundwater rises • Freezes & soil expands
Frost Creep “Soilfluction” (type of mass wastage)
Periglacial: Frailties • Vegetation – easily disturbed • Animal populations – sensitive to change • Low energy – slow decomposition • Thermal Expansion of permafrost: • Soil/Vegetation removed = thaw • Housing = heat • Pipelnes = crack • Drilling = heat • Short Term Economic Gain • Long Term Environmental Destruction
Chemical Physical Type of weathering in forefround? Type of weathering in the background?
Chemical Solution (Dissolution) • Water is the main operator: • Many ionic and organic compounds dissolve in water • Silica, K, Mg • Acid Reactions • Water + carbon dioxide <---> carbonic acid • Water + sulfur <---> sulfuric acid • Effective at breaking down minerals TYPE OF WEATHERING?
Solutionweathering • Water becomes acidic as ________________ dissolves in it to create a weak carbonic acid. • Carbonate rocks such as react with carbonic acid, to create a weaker form that is removed by solution. Carbon dioxide limestone Sinkhole
Spheroidal weathering is caused by chemical weathering of jointed rocks. The jointed rocks weather to form roughly spherical shapes.