1. Chapter 8 Earth Systems

2. Hybrid Electric Vehicles Although they reduce our consumption of liquid fossil fuels, HEV do come with environmental trade- offs. They require scarce metals for the motors and the batteries. Mining of these metals have severe environmental impacts such as adding acid, as well as harmful levels of metal to waterways, erosion of soil, and creates habitat destruction.

3. Earth’s Resources Most of the elements that we have on earth came from when the earth was first formed 4.6 billion years ago. They were distributed unevenly around the globe. Earth’s elements settled into place based on their mass leading to distinct vertical zonation.

4. Earth’s Layers The core is made up of Ni and Fe. The inner core is solid and the outer core is liquid. The mantle contains magma that slowly circulates in convection cells. The asthenosphere is composed of semi-molten, ductile rock. The Lithosphere, is a brittle outermost layer of the planet about 100km thick. It includes the solid upper mantle as well as the crust. Over the crust lies the thin layer of soil that allows life to exist on the plant. The crust and the overlying soil provide most of the chemical elements that compromise life.

5. Earth contains a finite supply of mineral resources We can’t extract indefinitely! Since we have already mined the most easily obtainable minerals, more energy must be used to extract the remaining resources.

6. Mineral Distribution around the world

7. Earth is constantly changing The core of the earth is very hot as a result of radioactive decay of various isotopes such as K, U, and Th which releases heat. The heat causes plumes of magma to well upward from the mantle to the lithosphere and create hot spots. The heat from the core also creates convection cells in the mantle that drives change and creation and renewal of Earth’s matrials in the Lithosphere.

8. Earth’s Tectonic Plates

9. Theory of Plate Tectonics World continents were originally one land mass= Pangaea Earth’s Lithosphere is divided into plates, most of which are in constant motion. The tectonic cycle is the sum of the processes that build up and break down the lithosphere. Oceanic plates lie beneath the oceans Continental plates lie beneath landmasses.

10. Convection and Plate Movement Oceanic plates are more dense and rich in Fe. Continental plates contain SiO 2, which is less dense than Fe. So they are lighter than the oceanic plates and typically rise above them. Both plates float on top of denser material below them and move by convection cell’s in the Earth’s mantle. As the plates move, the continents slowly drift.

11. Convection Plate Movement

12. Tectonic Plates

13. Seafloor Spreading As Oceanic plates move apart, rising magma forms new oceanic crust on the seafloor at the boundaries between those plates. When Oceanic plates meet Continental plates, old oceanic crust is pulled downward beneath the continental lithosphere and the heavier oceanic plate slides underneath the lighter continental plate= subduction

14. Consequences of Plate Movement As the Continents drifted over time, many changes occurred: climate changes, geographic barriers formed, species evolved or went extinct, some continents broke apart, islands formed, volcanoes formed, volcanic islands formed.

15. Geologic Time Scale

16. Type of Plate Contact Divergent plate boundaries= when plates move away from each other. Magma reaches the Earth’s surface and pushes up and out creating new rock= seafloor spreading. Convergent plate boundaries=plates move towards each other and collide, creating mountain ranges (Andes) Transform fault boundary= when plates move sideways past each other.

17. Type of Plate Boundaries

18. A fault zone in California is created where movement of the plates has occurred and rock near the plates margin fractures

19. Earthquakes Earthquakes occur when the rocks of the Lithosphere rupture unexpectedly along a fault. The epicenter is the exact point on the Earth’s surface directly above the location where the rock ruptures. Sometimes volcanic eruptions and earthquakes are observed at the same time, along the plate boundaries where tectonic activity is high.= Ring of Fire, around the Pacific Ocean.

20. Locations of Earthquakes and Volcanoes

21. Haiti Earthquake 2010 kills 200,000 The Richter Scale measures the largest ground movement that occurs during an earthquake. The scale is logarithmic, like the pH sale. So a 7.0 on the scale is ten times stronger than a 6.0. This earthquake registered as 7.0 in magnitude

22. Volcanic Eruptions Spew ash into the air that contains SiO 2. Dust, rock or lava, and cinder may cause a loss of life, habitat destruction and alteration and reduction in air quality.

23. THE ROCK CYCLE

24. Rocks The substance that the lithosphere is made of, contains one or more minerals (solid chemicals with uniform or crystalline structures that form under pressure and heat). Rocks can form from molten magma, by compression of sediments, and by exposure of rocks and other materials to heat and pressure

25. Igneous Rocks Form directly from molten magma Classified by their chemical composition as either basaltic (dark colored-with high amounts of Fe, Mg, and Ca, and is the dominant rock type in oceanic plates or granitic(lighter colored- composed of feldspar, mica and quartz, Si, Al, K, Ca and is the dominant rock type in continental plates) Intrusive- forms within Earth as magma, rises up, and cools in place underground. Extrusive-forms when magma cools above the surface rapidly, so minerals have little time for crystals to form; resulting in obsidian.

26. Sedimentary Rocks Form when sediments (mud, sand and gravel) are compressed by overlying sediments. Takes a long period of time to form Ex: sandstone, conglomerate and mudstone Contain the fossil record of our past, with plant and or animals remains that are compressed over eons

27. Metamorphic Rock Forms when sedimentary rocks, igneous rocks, or other metamorphic rocks are subjected to high temperatures and pressures. Ex: Slate, marble, and anthracite

28. Weathering Physical Weathering- the mechanical breakdown of rocks and minerals by water, wind, or variations in temperature. It can also be caused by plant roots and burrowing animals. It produces a greater surface area for chemical weathering processes to work on. Chemical Weathering-the break down of rock and minerals by chemical reactions, the dissolving of chemical elements from rocks, or both. It releases essential nutrients from rocks making them available for use by plants and animals. Acid rain promotes chemical weathering of certain minerals in the soil.

29. Erosion Erosion is the physical removal of rock fragments from a landscape or ecosystem. This can occur by wind, water and ice transport materials downslope under the force of gravity. Organisms that burrow under he soil can also cause erosion. Once the material has traveled a certain distance it accumulates and deposition occurs. Erosion can be accelerated by deforestation, overgrazing, road building and unmanaged construction activity.

30. Soil Formation is the 3 rd part of the geologic cycle. Soil is a mixture of geologic and organic components. Soil has many functions: plant growth, primary filter of water, provides habitat for bacteria, algae, fungi, insects and other animals, breaks down organic material and recycles nutrients that benefit plants and filters chemical compounds.

31. Soil Formation Is formed over thousand of years as a result of weathering of rocks and the accumulation of detritus from the biosphere. Young soil has less organic matter and fewer nutrients than a more mature soil. There are 5 factors that determine the properties of soil: the parent rock, climate, topography, organisms and time.

32. SOIL FORMATION

33. Parent Material- the type of rock of which it was composed of. Quartz-sand parent material produces nutrient poor soil. Soil that has CaCO 3 will have an abundant supply of Ca, have a high pH and support a high agricultural productivity. Climate-soil does not develop well in temperatures below freezing because organic matter can’t decompose well then. Soil formed in the tropics, is accelerated due to rapid weathering of rocks and minerals, leaching of nutrients, and the decomposition of organic detritus.

34. Topography- the surface slope and the arrangement of a landscape. Soil that forms on a steep slope is subject to erosion. Organisms-Plants remove nutrients from the soil and excrete organic acids that speed chemical weathering. Animals that burrow: earthworms, gophers, voles, mix the soil distributing organic and mineral matter. Time-As soil ages, and has organic matter in it over time, they become deep and fertile.

35. SOIL HORIZONS

36. Soil Horizons (Layers) O Horizon- at the surface of many soils, this layer contains organic detritus in various stages of decomposition. Pronounced in forest soils and in grasslands. A Horizon- topsoil, a mixture of organic material and minerals. E Horizon-only found in some acidic soils(beneath the O or A horizon), a zone of leaching or eluviation, Fe and Al are and dissolved organic acids are transported through here and deposited in the B horizon where they accumulate.

37. B Horizon-subsoil, composed of mineral material(metals) with little organic matter. If nutrients are present in the soil, they will be found here. C Horizon- always occurring below the B horizon, it is similar to the parent material. This horizon contains the least weathered soil.

38. SOIL PROPERTIES

39. Physical Properties of Soil Texture- determined by the percentage of sand, silt and clay (mineral particles of different sizes). Porosity- how quickly soil drains, depends on texture (Best agricultural soil is a mixture of sand, silt and clay which allows for water drainage and retention).Clay is useful where contminants need to be contained and won’t allow them to leach into groundwater.

40. Soil Porosity

41. Chemical Properties of Soil Clay particles are neg. charged and attract pos. charged mineral ions that are adsorbed(held on the surface) by the particles. These minerals can be released and used as nutrients by plants. This ability is called cation exchange capacity (CEC) or nutrient holding capacity. If a soil is more than 20% clay, its water retention is too high and the soil is waterlogged and the roots of plants become O 2 deprived. A balance must exist.

42. pH of soil Ca, Mg, K and Na can neutralize soil acids such as Al and H 2. Therefore they are considered bases. Soil acids are detrimental to plant growth Soil bases promote plant growth and are essential for plant nutrition. Base saturation- is a measure of the proportion of soil bases to soil acids (%). Soils with high CEC and high base saturation is likely to support high productivity.

43. Biological Properties of Soil Fungi, Bacteria and Protozoans are detritivores, which consume dead plant and animal tissues and recycle the nutrients they contain. Some bacteria fix nitrogen Rodents and Earthworms contribute to soil mixing and breakdown of large organic material. Snails and Slugs eat plant roots and some aboveground parts of the plant.

44. Crustal Abundance The average concentration of an element in the Earth’s crust. O 2, Si, Al and Fe make up 88% of the crust. However, the composition varies from location to location. Ores are concentrated accumulations of minerals from which economically valuable materials can be extracted. Most ores contain metals: Cu, Ni, Al. They are formed by a variety of processes. The reserve -is the known quantity of the resource that can be economically recovered.

45. S.W. VIRGINIA 2003 STRIP MINING FOR COAL

46. Open Pit Mining

47. MOUNTAIN TOP REMOVAL

48. Placer Mining

49. Subsurface mining

50. Types of Mining and their effects Environmental issues can include erosion, formation of sinkholes, loss of biodiversity, and contamination of soil, groundwater and surface water by chemicals from mining processes. In some cases, additional forest logging is done in the vicinity of mines to increase the available room for the storage of the created debris and soil. [28] Contamination resulting from leakage of chemicals can also affect the health of the local population if not properly controlled. [29] Extreme examples of pollution from mining activities include coal fires, which can last for years or even decades, producing massive amounts of environmental damage.erosion sinkholesbiodiversitygroundwatersurface water [28] [29]