Earth Geological Cycles & Bio and Chemical cycles
BioGeologicChemical Cycles In your notes: • Draw a picture of an earth section showing the following: • Earth center (core) • Inner core • Outer core • Mantle • Crust
Biogeochemical cycles • How the elements/chemicals move through the four major components of earth’s systems • Atmosphere: area above the earth’s surface • Hydrosphere: oceans, rivers, lakes, etc. • Lithosphere: rocks and soil • Biosphere: Plants and animals • We are going to be studying how cycles and Earth systems work together to balance the Earth. • Biogeochemical cycles • Bio – life • Geo – Earth • Chemical - elements
Biogeochemical Cycles • We are going to start at the beginning. Beginning of time that is. • How the earth is formed and how the earth moves. Our Geo cycles. • Tectonic plate movements • Rock cycle • Water cycle
Geological Cycle • Three types: • Tectonic Cycle • Plate formation • Plate/continent movement • Natural occurring Disasters • Hydrologic Cycle • Water movement through earth cycles • Rock Cycle • Processes of rock formations and movement
Plate tectonics • Pangaea Theory: • Approx. 250 Million years ago the continents were one major land mass called Pangaea. • This is proven through fossil record of plants and animals. • Also proven through similar mountain ranges on different continents today. • Plate movement caused the land mass to separate and form the oceans and lands we know today. • Where do you think our land masses will be in 150,000ma? • Answer in your notes.
Pangaea Earth today Earth 250ma
Pangaea puzzle • Part A: On A blank white sheet: • Each person will get a puzzle • Try to put the puzzle together of how you think the earth looked when the continents were together. • Once you have succeeded, label all parts what each continent would be today. • Include mountain ranges, deserts, tropical areas, glaciers. Etc.
Pangaea Puzzle Part B: 2nd Sheet of Paper • Draw the earth today. • Draw in all main mountain ranges, oceans, forests, tropical areas, deserts, etc. • Draw in the plate boundaries with direction of movement and name of plate. • Color in all parts.
Pangaea Puzzle. Part C: 3rd sheet of paper. • Draw a new earth on the third sheet of paper, • with how you think the earth will look in 150ma. • Think about how the plates are moving today. What direction each plate is moving. • What will the geography of the earth look like in 150 million years? • Label all parts: • Where would the the continents be today? • Possible mountain ranges, oceans, basins, deserts, forests, tropical areas, etc.
Convection and plate movement Convection – • Where molten magma rotates and cycles as it heats and cools inside the mantle. • in the mantle it causes oceanic plates to spread apart as new rock rises to the surface at the spreading zones.
Plate Tectonics • Ring of Fire: • Most volcanoes are not randomly distributed over the Earth's surface, but concentrated on the edges of continents, along island chains, or beneath the sea forming long mountain ranges. • More than half of the world's active volcanoes above sea level encircle the Pacific Ocean to form the "Ring of Fire."
Tectonic Plate Movement Plate Movements Convergent boundaries (subduction) • Where plates move towards each other Divergent boundaries (seafloor spreading) • Where plates move away from each other Transform Boundary (slip-strike) • Where one Plate slide past another plate.
Plate Movement • Juan de Fuca Subduction, Juan de Fuca Ridge, Cascade Range • The boundary between the Pacific and Juan de Fuca Plates is marked by a broad submarine mountain chain about 500 kilometers long (300 miles), known as the Juan de Fuca Ridge. Young volcanoes, lava flows, and hot springs were discovered in a broad valley less than 8 kilometers wide (5 miles) along the crest of the ridge in the 1970s. The ocean floor is spreading apart and forming new ocean crust along this valley or "rift" as hot magma from the Earth's interior is injected into the ridge and erupted at its top. In the Pacific Northwest, the Juan de Fuca Plate plunges beneath the North American Plate. As the denser plate of oceanic crust is forced deep into the Earth's interior beneath the continental plate, a process known as "subduction", it encounters high temperatures and pressures that partially melt solid rock. Some of this newly formed magma rises toward the Earth's surface to erupt, forming a chain of volcanoes above the subduction zone. -- Modified from Brantley, 1994, Volcanoes of the United States, U.S. Geological Survey General Interest Publication 376-846. Graphic by Lyn Topinka, 1999.
Plate tectonics • Playing with boundaries: (Activity Lab) • Background/Discussion: • What is Plate tectonics? • Why is it important to know about how the plates move? • How do plate tectonics work? (the mechanisms that rule movement) • How do plate movements form different land/ocean geography?
Plate Tectonics • Basics of lab: • Create a lab that shows the process of plate tectonics and environmental impact. • Must be able to be performed by others. (following your directions) • Must include the following processes: • Movement of the plates (all three) • Transform • Divergent • Convergent • Land Formation (at least 2) • Mechanics of plate movement that cause natural disasters. (at least 2)
Rock Cycle Please copy diagram in your notes. Include land formations and plate boundary.
Rock Cycle • Igneous Rock: • Magma (molten rock under earth’s crust) or lava (molten rock on earth’s surface) that forms and solidifies is called igneous rock. • Two types: • Intrusive rock – forms beneath the earths surface inside the crust • Extrusive rock – forms as lava cools on the surface of earth.
Rock Cycle • Igneous rock: • Identifiable by texture, shape, density and mineral composition and color. • Slower it cools (usually intrusive) = form large crystals • ex: granite • Faster it cools (usually extrusive) = form small crystals • ex: Obsidian (glassy), pumice (porous)
Rock Cycle • Sedimentary Rock: • Eroded and broken rock moved by wind, water, glacial movements form sediments. By: • Cementation – lithification of sediments by binding with substances like iron oxide, silicates, or calcium carbonate. • Ex: sandstone, conglomerate • Compression and compaction – weight and pressure force sediments for squish together and bond. • Ex: Shale • Two types of textures: • Clastic – composed of individual rock fragments bonded together. • Crystalline – composed of crystals • Fossils are found here. • Most form lines or strata with the rock sediments.
Rock Cycle • Metamorphic Rocks: • Form from rocks undergoing pressure and heat • Usually associated with mountains • Undergoes recrystalization – new arrangement of atoms and molecules. Where sed. and ig. rocks reform to form new rocks. • Foliated – form distinct layers in the rock. • Folding or curving – result of intense heat and pressure. • Ex: gneiss, slate
Hydrologic Cycle(aka: Water cycle) • Where does water come from? • What elements form water? • Why is the water cycle so important to the survival of the earth?
Hydrologic Cycle • Water makes up ~70% of the earth • Break down: • Oceans – ~ 97% • Land – ~2.5 % • Atmosphere - <~1% • Let’s take a quick look at the water cycle. (will spend more time when we talk about water resources later this year.
Hydrologic Cycle Diagram of the natural water cycle