Structure of the Earth - understanding of the Earth’s structure based in minute fraction of total depth (less than 8 miles)Lithospheric PlatesDiastrophism- Refers to the deformation of Earth’s crustGEOG 1114 1st Edition Lecture 30Outline of Last Lecture -Karst topography continued-Features continued-Sinkholes-Underground streams-Hydrothermal featuresOutline of Current Lecture Review of chapters 13-15Current Lecture Lecture 12 Ch. 13 - Introduction to LandformsConcepts and terms involved in understanding the Earth’s Structure and compositionStructure of the Earth - understanding of the Earth’s structure based in minute fraction of total depth (less than 8 miles)Crust – outermost shell- depth of 5 km below the ocean to near 20 km below land- Less then 1% of the Earth’s volume, .04% of Earth’s massMoho Layer: base of crust; significant change in mineralMantle - Expands to depth of 2900 km (1800 miles): largest of four shells. Makes up 84% of total volume, 67% of total mass.These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.-Lithosphere- top of moho layer- hard ridged layer includes the crust-Asthenosphere- to about 200 miles; hot, tar-like rocks; pliable. -Mesosphere- lower mantle- Outer Core – Molten (magma) extends to depth of 5000 kmInner Core – Dense mass with a radius of about 1450 km. Primarily made of iron/nickel of iron/silicate. Magnetic field of Earth controlled by the outer core. Magnetic poles not the same as the axial poles.Major rock typesIgneous: Rock formed by the solidification of molten material called magma. Formed by the solidification of molten materials (magma). Lava- molten rock when it flows into Earth’s surface. Intrusive Igneous Rocks: (plutonic) – Rocks cool beneath earth’s surface. Surrounding rocks insulate the magma intrusion, cools slowly. Individual minerals in a plutonic rock can grow to large size. (Granite Gabbro)Extrusive Igneous Rocks: (volcanic) – Form on Earth’s surface – when magma forces its way to surface. Cools rapidly causing a glassy and/or fine-grained rock surface. Outcrop rock at surface. (Basalt and Obsidian)*Basalt erodes more quickly then granite*Igneous rocks, particularly granite, form about 80% of the earth’s crust (continents and oceans). But sedimentary rocks often cover them. They become important to landform development if exposed via uplift or erosion.Sedimentary Rocks: Rock formed of sediment that is consolidated by the combination of pressure and cementation.-Most widespread rock type of the land surface.Consist of small particles of rock debris or organic material that were deposited by water, wind, or ice as sediments and were later consolidated by the combination of pressure and cementation.This cementing takes place when sediments are laid down, buried and compacted into horizontal layers called strata. Although originally deposited and formed in horizontal layers, the strata maylater be uplifted, tilted, and deformed by pressures within the EarthThere are many types distinguished on the basis of grain size. How they were formed (mechanically, chemically, or organically). Strata- Horizontal layers of sedimentary rock; sometimes tilted. Conglomerates- compacted gravel, formed mechanically- cemented under pressure.Sandstone- compacted sandstone formed mechanicallyLimestone- chemically accumulated rock composed of calcium carbonate; coral and sea animalsShale- cemented clay and silt, formed mechanicallyCoal- organically accumulated; compacted skeletal remains of organismsMetamorphic Rocks: Rock that was originally something else but has been drastically changed by massive forces of heat and/or pressure working on if from within the Earth.Causing a “cooking” of rocks-Rearranges the crystal structure f the original rock. -Denser and less porous than its sedimentary or igneous parentVery resistant to weathering (erosion)Types include:Slate: derived from shaleSchist: derived from shale, basaltGneiss: derived from graniteQuartzite: derived from sandstoneMarble: derived from limestoneLandform structure and reliefTopography- surface configuration of EarthLandform – Individual topographic feature of any sizeGeomorphology – Study of landformsRelief – Difference in elevation between highest and lowest pointsStructure – nature, arrangements and orientation of landforms (slope)2 opposing forces of landform development: Internal/ExternalInternal: Surface disturbance produced by the earth’s internal thermal energy. Earth’s internal heat generates extremely strong processes that result in crustal movements.They are generally constructive, uplifting, building forces that tend to increase the relief of the land surface.They include:Crustal rearrangements – earth’s crust is plasticPlate Tectonics – theory of lithospheric plate movementsVolcanism – movement of magma from interior of earth to surfaceDiastrophism – compressional stresses of all the aboveThese increase the relief of the land’s surfaceExternal: Molding of peaks, slopes, valleys, and plains by the work of gravity, water, wind, and ice.Denudation: Overall effect of external forces which level and lower the Continental surface)Accomplished by:Weathering: Breaking up of rock in small components: physical and chemicalMass wasting: downslope movement of broken material due to gravity (rock fall, rock slide)Erosion: extensive and distinct removal of fragmented rock Six Factors of Landform DevelopmentTectonic Activity: Intensity of crustal motions produced by earth’s internal energy Geologic Structure: Nature and arrangements of materialDenudation: removal and deposition of rock material via weathering and erosion.Climate: Temp. PPTN, humidity, and wind all effect rates of erosion, deposition, weathering and types of drainage.Biota: Vegetation, soils, organisms. Humans, all can influence rates and type of landform developmentTime: Vastness/magnitude Earth 4.6 billion years old. Processes are very slow. Dinosaurs – 160 million years. Results are high magnitudesLecture 13 Ch. 14 - Internal ProcessTheory of Plate Tectonics: how new crust is formed; how crust is consumed Theory of crustal rearrangement based on the moment of continent-sized lithospheric plates.The Breakup of PangaeaSuper Continent, made of up existing continents put together