Chapter 1 Introduction to Earth Science PDF

Chapter 1 Lecture Earth Science Fourteenth Edition, Global Edition Introduction to Earth Science Jennifer Mangan James Madison University © 2015 Pearson Education Ltd.  Earth Science All sciences that seek to understand Earth...

Chapter 1 Lecture Earth Science Fourteenth Edition, Global Edition Introduction to Earth Science Jennifer Mangan James Madison University © 2015 Pearson Education Ltd.  Earth Science All sciences that seek to understand Earth Understanding of Earth’s neighbors in space © 2015 Pearson Education Ltd.  Earth Science Earth Science includes – Geology – literally the “study of Earth” – Oceanography – a study of the ocean – Meteorology – the study of the atmosphere and the processes that produce weather – Astronomy – the study of the universe © 2015 Pearson Education Ltd.  Earth Science is Environmental Science Natural hazards Resources People Influence Earth processes © 2015 Pearson Education Ltd.  Earth Science: Scales of Space and Time Geologic Time – Span of time since Earth’s formation – Earth is 4.6 billion years old – Concept of “recent” is different Geologic Time Scale – Divides history of Earth into different units © 2015 Pearson Education Ltd.  Magnitude of Geologic Time © 2015 Pearson Education Ltd.  Scientific Inquiry Science assumes the natural world is – Consistent – Predictable Goal of science – To discover patterns in nature – To use the knowledge to predict © 2015 Pearson Education Ltd.  Scientific Inquiry An idea can become a – Hypothesis (tentative or untested explanation) – Theory (tested and confirmed hypothesis) – Paradigm (a theory that explains a large number of interrelated aspects of the natural world) Scientific method – Gather facts through observation – Formulate hypotheses and theories © 2015 Pearson Education Ltd.  Observation and Measurement © 2015 Pearson Education Ltd.  Scientific Inquiry Scientific knowledge is gained through – Following systematic steps Collecting facts Developing a hypothesis Conduct experiments Reexamine the hypothesis and accept, modify, or reject – Theories that withstand examination – Totally unexpected occurrences © 2015 Pearson Education Ltd.  Early Evolution of Earth Origin of Earth – Most researchers believe that Earth and the other planets formed at essentially the same time Nebular theory – Solar system evolved from an enormous rotating cloud called the solar nebula – Nebula was composed mostly of hydrogen and helium © 2015 Pearson Education Ltd.  Early Evolution of Earth Nebular theory continued – About 5 billion years ago the nebula began to contract – Assumes a flat, disk shape with the protosun (pre-Sun) at the center – Inner planets begin to form from metallic and rocky clumps – Larger outer planets began forming from fragments with a high percentage of ices © 2015 Pearson Education Ltd.  The Nebular Theory © 2015 Pearson Education Ltd.  Early Evolution of Earth Formation of Earth’s layered structure – As Earth formed, the decay of radioactive elements and heat from high-velocity impacts caused the temperature to increase Iron and nickel began to melt and sink toward the center Lighter rocky components floated outward, toward the surface – Gaseous material escaped from Earth’s interior to produce the primitive atmosphere © 2015 Pearson Education Ltd.  Earth’s Spheres Hydrosphere – Ocean – the most prominent feature of the hydrosphere Nearly 71 percent of Earth’s surface About 97 percent of Earth’s water – Also includes fresh water found in streams, lakes, and glaciers, as well as that found underground © 2015 Pearson Education Ltd.  Hydrosphere © 2015 Pearson Education Ltd.  Earth’s Spheres Atmosphere – Thin, tenuous blanket of air – One half lies below 5.6 kilometers (3.5 miles) © 2015 Pearson Education Ltd.  Earth’s Spheres Biosphere – Includes all life – Concentrated near the surface in a zone that extends from the ocean floor upward for several kilometers into the atmosphere © 2015 Pearson Education Ltd.  Earth’s Spheres Geosphere – Solid Earth – Extends from surface to the center of the planet – Largest of Earth’s four spheres © 2015 Pearson Education Ltd.  Geosphere Solid Earth – Based on compositional differences, it consists of the crust, mantle, and core – Divisions of the outer portion are based on how materials behave © 2015 Pearson Education Ltd.  Earth’s Layered Structure © 2015 Pearson Education Ltd.  Geosphere Crust – Earth’s relatively thin, rocky outer skin – Continental crust Less dense, many rock types Granitic – Oceanic crust Dense, basaltic rock © 2015 Pearson Education Ltd.  Geosphere Mantle – Solid, rocky shell – More than 82 percent of Earth’s volume – Upper mantle Lithosphere – entire crust and uppermost mantle Asthenosphere – relatively soft layer – Lower mantle Very hot, strengthens with depth © 2015 Pearson Education Ltd.  Geosphere Core – Iron-nickel alloy – Outer core Liquid layer Earth’s magnetic field – Inner core Solid © 2015 Pearson Education Ltd.  The Mobile Geosphere Plate tectonics – Earth’s lithosphere is broken into slabs (lithospheric plates) that are in continuous motion. © 2015 Pearson Education Ltd.  Earth’s Major Lithospheric Plates © 2015 Pearson Education Ltd.  Plate Motion Plates move very slowly Three types of plate boundaries – Divergent – plates pull apart – Convergent – plates move together – Transform fault – plates slide past each other © 2015 Pearson Education Ltd.  Convergent and Divergent Boundaries © 2015 Pearson Education Ltd.  The Face of Earth Continents – Flat features that average 0.8 km (0.5 mi) in elevation – Granitic rocks Ocean basins – Average 3.8 km (2.8 mi) below sea level – Basalitic rocks © 2015 Pearson Education Ltd.  Major Features of Continents Mountain Belts – Principally the circum-Pacific belt and the Alps/Himalayas Stable Interior – Shields – expansive, flat regions of deformed crystalline rock – Stable platforms – deformed rocks covered by sedimentary rocks. © 2015 Pearson Education Ltd.  The Continents © 2015 Pearson Education Ltd.  Major Features of Ocean Basins Continental Margins – Portions of seafloor adjacent to major landmasses – Includes: Continental shelf – gently sloping platform extending seaward from shore Continental slope – steep drop off at edge of continental shelf Continental rise – more gradual incline; continental slope merges with thick accumulation of sediments © 2015 Pearson Education Ltd.  Major Features of Ocean Basins Deep-Ocean Basins – Between continental margins and oceanic ridges – Abyssal plains – flat features of deep-ocean basins – Deep-ocean trenches – deep depressions in ocean floor – Seamounts – submerged volcanic structures © 2015 Pearson Education Ltd.  Major Features of Ocean Basins Oceanic Ridge – Also called mid-ocean ridge – Includes Mid-Atlantic Ridge and East Pacific Rise – Continuous mountain belt that winds around globe – Many layers of igneous rock © 2015 Pearson Education Ltd.  Earth as a System Earth is a dynamic body with many separate but highly interacting parts or spheres Earth system science studies Earth as a system composed of numerous parts, or subsystems System – any size group of interacting parts that form a complex whole © 2015 Pearson Education Ltd.  Earth as a System System – Closed systems are self-contained (e.g., an automobile cooling system) – Open systems – both energy and matter flow into and out of the system (e.g., a river system) © 2015 Pearson Education Ltd.  Earth System Science Earth as a system – Consists of a nearly endless array of subsystems (e.g., hydrologic cycle, rock cycle) © 2015 Pearson Education Ltd.  Earth System Science Earth as a system – Sources of energy Sun – drives external processes such as weather, ocean circulation, and erosional processes Earth’s interior – drives internal processes including volcanoes, earthquakes, and mountain building – Humans are part of the Earth system © 2015 Pearson Education Ltd.