1. 1 Chapter 1 Earth Systems Earth Science and the Environment (4th ed) Thompson & Turk

2. 1.2 The Earths four spheres Geosphere the solid earth Hydrosphere the watery part of our planet Atmosphere the gaseous layer above Biosphere the living realm of organisms 3. Geosphere (Solid Earth) Formed by Accretion A. Clouds of dust and gas form by accretion the attraction and accumulation of matter. B. Material gets compressed and produces heat. Heat melts heavy metals like Nickel and iron C. The lighter elements are displaced and move to the surface density stratification separation of materials by density 4. Inner Core solid core of iron and nickel under high pressure and temperature Outer Core liquid metals circulate Around the solid inner core Mantle has two parts: the upper mantle which is made of rock that is pliable the lower mantle which made of solid rock that is very hot Crust thin outermost layer of the earth made primarily of silicates 5. 1.2 The Earths four spheres 3 major layers of Earths Geosphere Dense metallic core Outer core liquid, inner core solid, 6000C Ni-Fe Less-dense rocky mantle Changes with depth, some parts solid, others weak and plastic-like, flowing slowly Even less dense surface crust Crustal material varies widely 6. Fig. 1.5, p.6 7. 1.2 The Earths four spheres Lithosphere the crust and upper part of mantle Average 100km thick Broken up into tectonic plates Plates float atop the weaker material 7 major (and several minor) plates are in constant motion 8. 1.2 The Earths four spheres Hydrosphere all Earths water Oceans Glaciers Ground water Streams and lakes Atmosphere 9. Hydrosphere created by Heating and Differentiation Hydrogen and Oxygen released by volcanic activity Water molecules form and collect into vapor Vapor clouds cool and condensed vapor falls as rain boils off immediately Vapor reforms into water and the process continues for millions of years Eventually surface cools and water begins to collect in rock basins 10. Fig. 1.8, p.7 11. Atmosphere Formed by heating and differentiation Step 1. Primordial (ancient) gases Lost to space Due to solar winds Step 2. Volcanic venting & Icy comets release carbon monoxide (CO), carbon dioxide(CO2), ammonia (NH4), methane (CH4) and water vapor(H2O) Step 3. Steady additions of gases From volcanoes builds up the volume Of atmosphere Step 4. Blue Green algae convert Carbon dioxide to oxygen 12. 1.2 The Earths four spheres Atmosphere the gas layer surrounding the solid Earth Mixture of N, O, CO2, Ar, other gases 99% in 1st 30km Acts as filter & blanket, and as heat transport medium 13. 1.2 The Earths four spheres Biosphere zone of living things Water, land, air all contain life Life is affected by the environment Life also alters the environment 14. Fig. 1.4, p.5 15. 1.3 Earth Systems Systems an assemblage/combination of interacting components forming a complex whole i.e.: the human body, a bacterium, an ecosystem Each sphere is a system 16. 1.3 Earth Systems Spheres are subdivided into component systems Surface systems mainly solar powered Mass and energy both move Chemical reactions change materials Internal systems radioactively powered Spheres also linked into conjoined subsystems 17. 1.5 Threshold and feedback effects Threshold effect slow or no initial change to environmental change When threshold point is passed, change becomes rapid Feedback mechanism one change affects another system component, amplifying original effect 18. Fig. 1.9, p.8 19. Study of Earths Systems Planets are active, dynamic and in continuous state of change. Planetary changes are driven by complex interactions among the individual systems. Earths systems consist of Geosphere Hydrosphere Atmosphere Biosphere 20. Earth Systems A system is any assemblage or combination of interacting components that form a complex whole. Systems are driven by matter and energy. Larger systems are composed of many smaller systems The size of systems can vary dramatically. 21. Changes to systems Changes can occur to systems in two ways Events can occur slowly but become significant over long periods of time Observation of these type of changes gave birth to the gradualism or uniformitarianism principles. Improbable events can occur regularly These more catastrophic events occurred between periods of relative tranquility and gave birth to the principle of catastrophism huge events that change the course of Earths history 22. Changes to systems Systems have parameters under which they operate Changes to those parameters cause changes to the system Slow changes may appear to have no effect until a threshold level is reached Once the threshold level is breached changes to the system can occur in rapid and dramatic ways Example: ice melting 23. Changes to systems Because systems are complex interactions of individual parts changes to one part may cause changes to another part which may cause increased changes to the first part HUH???? Its called a feedback mechanism it occurs when a small change to the system affects another component of the system which amplifies the original effect which perturbs the system even further example albedo and ice melt. 24. Human Impact Humans are a part of the complex system of the biosphere Through increased numbers we have had an impact on the earths systems Through increased technology we have had an impact on the earths systems Will the system continue to function as it has or will the human impact eventually break the system? We must first understand the systems to determine the extent to which we are affecting those systems