Survey
* Your assessment is very important for improving the work of artificial intelligence, which forms the content of this project
Download Plate Tectonice
Document related concepts
no text concepts found
Transcript
Periods of Glaciation and their locations Plate Tectonics and Long-Term Climate Tectonic Plates Earth’s Structure Plate Margins Earth’s Magnetic Field 1 Magnetization of Ocean Crust Gondwana and the South Pole Polar Position Hypothesis Polar Position Hypothesis • Ice sheets should appear on continents when they are located at polar or near polar latitudes • No ice should appear anywhere on Earth if no continents exist anywhere near the poles • Necessary but not sufficient • Greenhouse gases could make up difference Sites of Carbon Dioxide Input into the Atmosphere Carbon Cycling 2 Spreading Rate Hypothesis • Faster Sea Floor Spreading Releases more Carbon Dioxide into the Atmosphere • 50% Faster 100 million years ago than today and there was more carbon dioxide in the atmosphere then than today • Needs Negative Feedback to partially counter changes in atmospheric carbon dioxide caused by sea floor spreading Age of the Seafloor Uplift Weathering Hypothesis • Mountains are made when continents collide • This causes increased weathering which removes carbon dioxide from atmosphere Evaluation of the Sea Floor Spreading Hypothesis Negative Feedback from Spreading Rate Hypothesis Evaluation of Uplift Weathering Hypothesis – Rocks slide down slopes – mountain glaciers grind rocks – increased precipitation on upwind side of mountain erodes rocks 3 Brief Glaciation 430 million years ago (only 1 million years) • Possibly caused by burial of organic carbon (that is the formation of fossil fuels) Earth Today Note that this Projection shows the whole Earth Continental Positions Through the Last 500 million years Cambrian Period 600-500 million years ago Starfish & snails Climate becoming warm North America during Early Cambrian Period 600 million years ago Ordovician Period 500-440 million years ago First fish & corals Climate moderate to warm 4 North America during Late Ordovician Period 440 million years ago Silurian Period 440-400 million years ago First land plants and animals Climate warm Devonian Period 400-350 million years ago North America during Early Devonian Period 400 million years ago First trees & insects Widespread glaciation Becoming warm North America during Late Devonian Period 350 million years ago Laurasia drifting toward Gondwana Carboniferous Period 350-270 million years ago First reptiles & conifers Warm then glacial 5 North America during Early Permian Period 270 million years ago Permian Period 270-230 million years ago Ice Ages Pangea Triassic Period 230-180 million years ago Late Permian Glaciations 250 million years ago First dinosaurs Plate Tectonics - Final Stages of Pangaea Breaking Up x x x x x x Equator x x Laurasia splits from Gondwana Jurassic Period 180-130 million years ago Dinosaurs’ heyday First birds & small mammals, crocodiles & flying reptiles Very warm Scotland 18ºF warmer 6 Cretaceous Period 130-70 million years ago End of dinosaurs Many extinctions Oligocene Period 40-25 million years ago Palaeocene Period 70-60 million years ago Early horses Modern flora India-Asia Collision forming Tibet First monkeys & man-like apes Earth Today 7
Related documents