Ch 15 Geology Part 1

Core Case Study: The Nanotechnology Revolution Nanotechnology uses science and engineering to create materials out of atoms and molecules at the scale of less than 100 nanometers. Little environmental harm: Does not use renewable resources. Potential biological concerns. Can move through cell membranes: Figure 15-1

GEOLOGIC PROCESSES The earth is made up of a core, mantle, and crust and is constantly changing as a result of processes taking place on and below its surface. The earth’s interior consists of: Core: innermost zone with solid inner core and molten outer core that is extremely hot. Mantle: solid rock with a rigid outer part (asthenosphere) that is melted pliable rock. Crust: Outermost zone which underlies the continents.

GEOLOGIC PROCESSES Major features of the earth’s crust and upper mantle. Figure 15-2

Oceanic crust (lithosphere) Abyssal plain Continental slope Folded mountain belt Volcanoes Abyssal plain Abyssal floor Oceanic ridge Abyssal floor Abyssal hills Trench Craton Oceanic crust (lithosphere) Abyssal plain Continental slope Continental shelf Continental rise Mantle (lithosphere) Continental crust (lithosphere) Mantle (lithosphere) Figure 15.2 Natural capital: major features of the earth’s crust and upper mantle. The lithosphere, composed of the crust and outermost mantle, is rigid and brittle. The asthenosphere, a zone in the mantle, can be deformed by heat and pressure. Mantle (asthenosphere) Fig. 15-2, p. 336

Inner core Tectonic plate Fig. 15-3, p. 337 Spreading center Ocean trench Plate movement Subduction zone Oceanic crust Continental crust Material cools as it reaches the outer mantle Cold dense material falls back through mantle Hot material rising through the mantle Mantle convection cell Two plates move towards each other. One is subducted back into the mantle on a falling convection current. Mantle Hot outer core Inner core Collision between two continents Tectonic plate Oceanic tectonic plate Figure 15.3 Natural capital: the earth’s crust is made up of a mosaic of huge rigid plates, called tectonic plates, which move around in response to forces in the mantle. PLAY VIDEO

GEOLOGIC PROCESSES Huge volumes of heated and molten rack moving around the earth’s interior form massive solid plates that move extremely slowly across the earth’s surface. Tectonic plates: huge rigid plates that are moved with convection cells or currents by floating on magma or molten rock.

The Earth’s Major Tectonic Plates Figure 15-4

Animation: Geological Forces PLAY ANIMATION

The Earth’s Major Tectonic Plates The extremely slow movements of these plates cause them to grind into one another at convergent plate boundaries, move apart at divergent plate boundaries and slide past at transform plate boundaries. Figure 15-4

PLAY ANIMATION PLAY ANIMATION PLAY ANIMATION Fig. 15-4, p. 338 Figure 15.4 Natural capital: the earth’s major tectonic plates. The extremely slow movements of these plates cause them to grind into one another at convergent plate boundaries, move apart from one another at divergent plate boundaries, and slide past one another at transform plate boundaries. QUESTION: What plate are you floating on? PLAY ANIMATION PLAY ANIMATION PLAY ANIMATION Fig. 15-4, p. 338

INDIA-AUSTRALIAN PLATE EURASIAN PLATE NORTH AMERICAN PLATE ANATOLIAN PLATE JUAN DE FUCA PLATE CARIBBEAN PLATE CHINA SUBPLATE ARABIAN PLATE AFRICAN PLATE PHILIPPINE PLATE PACIFIC PLATE SOUTH AMERICAN PLATE NAZCA PLATE INDIA-AUSTRALIAN PLATE SOMALIAN SUBPLATE Figure 15.4 Natural capital: the earth’s major tectonic plates. The extremely slow movements of these plates cause them to grind into one another at convergent plate boundaries, move apart from one another at divergent plate boundaries, and slide past one another at transform plate boundaries. QUESTION: What plate are you floating on? ANTARCTIC PLATE Divergent plate boundaries Convergent plate boundaries Transform faults Fig. 15-4a, p. 338

Tectonic Plates

Volcanic Activities

Earthquake Activities 65’-95’

GEOLOGIC PROCESSES The San Andreas Fault is an example of a transform fault. Figure 15-5

Wearing Down and Building Up the Earth’s Surface Weathering is an external process that wears the earth’s surface down. Figure 15-6

Parent material (rock) Biological weathering (tree roots and lichens) Chemical weathering (water, acids, and gases) Physical weathering (wind, rain, thermal expansion and contraction, water freezing) Figure 15.6 Natural capital: physical, chemical, and biological processes can weather or convert rock into smaller fragments and particles. It is the first step in soil formation. PLAY ANIMATION Particles of parent material Fig. 15-6, p. 340

MINERALS, ROCKS, AND THE ROCK CYCLE The earth’s crust consists of solid inorganic elements and compounds called minerals that can sometimes be used as resources. Mineral resource: is a concentration of naturally occurring material in or on the earth’s crust that can be extracted and processed into useful materials at an affordable cost.

General Classification of Nonrenewable Mineral Resources The U.S. Geological Survey classifies mineral resources into four major categories: Identified: known location, quantity, and quality or existence known based on direct evidence and measurements. Undiscovered: potential supplies that are assumed to exist. Reserves: identified resources that can be extracted profitably. Other: undiscovered or identified resources not classified as reserves

General Classification of Nonrenewable Mineral Resources Examples are fossil fuels (coal, oil), metallic minerals (copper, iron), and nonmetallic minerals (sand, gravel). Figure 15-7

Decreasing cost of extraction Undiscovered Identified Economical Reserves Other resources Decreasing cost of extraction Not economical Figure 15.7 Natural capital: general classification of nonrenewable mineral resources. (The area shown for each class does not represent its relative abundance.) Hypothetically, other resources could become reserves because of rising mineral prices or improved mineral location and extraction technology. In practice, geologists expect only a fraction of these resources to become reserves. QUESTION: How might this classification scheme change if a full-blown nanotechnology revolution (p. 335) takes place over the next two decades? Decreasing certainty Known Existence Fig. 15-7, p. 341

GEOLOGIC PROCESSES Deposits of nonrenewable mineral resources in the earth’s crust vary in their abundance and distribution. A very slow chemical cycle recycles three types of rock found in the earth’s crust: Sedimentary rock (sandstone, limestone). Metamorphic rock (slate, marble, quartzite). Igneous rock (granite, pumice, basalt).

Rock Cycle PLAY ANIMATION Figure 15-8