Geology of Rock Deformation and Mountain Building, Resúmenes de Geología

¡Descarga Geology of Rock Deformation and Mountain Building y más Resúmenes en PDF de Geología solo en Docsity! CHAPTER OUTLINE Introduction Rock Deformation-How Does It Occur? GEOLOGY IN UNEXPECTED PLACES: Ancient Ruins and Geology Strike and Dip-the Orientation of Deformed Rock Layers Deformation and Geologic Structures GEO-FOCUS 10.1: Geologic Maps-Their Construction and Uses Deformation and the Origin of Mountains Earth's Continental Crust Geo-Recap AN do ANS + Rock deformation involves changes in the shape or volume or both of rocks in response to applied forces. + Geologists use several criteria to differentiate among geologic structures such as tolds, joints, and faults. » Correcitly interpreting geologic structures is important in human endeavors such as constructing highways and dams, choosing sites for power plants, and finding and extracting some resources. + Deformation and the origin of geologic structures are important in the origin and evolution of mountains. + Most of Earth's large mountain systems formed, and in some cases continue to form, at or near the three types of convergent plate boundaries. » Terranes have special significance in mountain building. » Earth's continental crust, and especially mountains, stands higher than adjacent crust because of its composition and thickness. 92008 Brooks/Cole - Thomson Fig. 10-1b, p. 260 (0 2006 Brooks/Cole - Thomson Fig. 10-2, p. 261 Compression - => -A | A (a) Tension o j — ELELS => (b) Shear 0 2 e E — 22006 Brooks/Cole - Thomson Fig. 10-3, p. 261 62008 Brooks/Cole - Thomson Fig. 10-5a, p. 263 82008 Brooks/Cole - Thomson Fig. 10-5b, p. 263 Strike and dip symbol Water surface Fig. 10-6, p. 264 (82006 Brooks/Cole - Thomson 8 2006 Brooks/Cole - Thomson Fig. 10-7b, p. 265 (02006 Brooks/Cole - Thomson Fig. 10-8, p. 266 Syncline Anticline 6 2006 Brooks/Cole - Thomson Fig. 10-9, p. 266 (0 2006 Brooks/Cole - Thomson Fig. 10-10b, p. 267 Oldest Youngest exposed exposed rock unit rock unit (02005 Brooks/Cole - Thomson Fig. 10-11, p. 267 Inclined Overtuned Axial plane Recumbent Oldest Youngest LIPZS 7 ===> LTGDDA qe Fig. 10-12, p. 268 8 2006 Brooks/Cole - Thomson Recumbent Oldest rocks Y 7 ===S y AA > A > Raja SA Y Axial =- >>> 9 2008 Brooks/Cole - Thomson Fig. 10-12c, p. 268 92006 Brooks/Cole - Thomson Fig. 10-12d, p. 268 ounges expose 0cs Angle of plunge lunging lungaing — luraging an icline sncline anicline (c) Fig. 10-13, p. 269 8 2006 Brooks/Cole - Thomson 0 2006 Brooks/Cole - Thomson (c) 8 2006 Brooks/Cole - Thomson (a) Dome Oldest exposed rocks [K] Cretaceous Younger El Triassic [€] Carboniferous [E] Cambrian [PE] Precambrian (b) Basin Youngest exposed rocks Fig. 10-14, p. 270 Oldest exposed rocks (a) Dome Fig. 10-14a, p. 270 (0 2006 Brooks/Cole - Thomson Fig. 10-15a, p. 271 8 2006 Brooks/Cole - Thomson > 2006 Brooks/Cole - Thomson Fig. 10-15b, p. 271 Faults are very common geologic structures. They are fractures along which movement takes place parallel to the fracture surface. A block of rock adjacent to a fault may move up or down a fault plane—that ís, up or down the dip of the fault. These are thus called dip-slip faults. On the other hand, movement may take place along a fault's strike, giving ==". rise to strike-slip faults. Movement on faults and the release of stored energy are responsible for earthquakes (see Chapter 8). Most faults are found at the three major types of plate boundaries: 'overthrust rock. a Iight-colored line on the mountainside. o rost oline siab ot. Concept Art, p. 272 0) 2006 Brooks/Cole - Thomson (b) Reverse faut 4c) Thrust faun (0) Strice-slip faut (e) Oblique-Slip fautt Fig. 10-17, p. 275 2 2006 Brooks/Cole - Thomson (a) Normal fault Fig. 10-17a, p. 275 2 2006 Brooks/Cole - Thomson (b) Reverse fault Fig. 10-17b, p. 275 8) 2006 Brooks/Cole - Thomson (e) Oblique-slip fault 6 2006 Brooks/Cole - Thomson Fig. 10-17e, p. 275 £) 2006 Brooks/Cole - Thomson (a) Graben a ri as (b) 02008 Brooks/Cole - Thomson Fig. 10-19, p. 277 33 North z Ni (c) Figure 2, p. 279 8) 2006 Brooks/Cole - Thomson 9 2006 Brooks/Cole - Thomson Figure 2a, p. 279 Indian-Australian plate Antarctic plate American Caribbean 8 2006 Brooks/Cole - Thomson Fig. 10-20, p. 280 Accretionary Back-arc Continental basin crust Continental crust Fig. 10-21, p. 281 (8 2006 Brooks/Cole - Thomson Accretionary Back-arc Continental basin crust Volcanic island arc Sediment layer Oceanic crust (0:2006 Brooks/Cole - Thomson Fig. 10-21a, p. 281 Passive continental margin Continental lithosphere Oceanic lithosphere Asthenosphere (a) Sediments Active continental margin Sea level Continental lithosphere Oceanic lithosphere Asthenosphere (b) Deformation Continental lithosphere Oceanic lithosphere Asthenosphere (c) (0 2006 Brooks/Cole - Thomson Fig. 10-22, p. 282 Continental lithosphere Oceanic lithosphere Asthenosphere (0 2006 Brooks/Cole - Thomson Fig. 10-22a, p. 282 Sediments Active continental margin Sea level Continental lithosphere Oceanic lithosphere Asthenosphere 0 2006 Brooks/Cole - Thomson Fig. 10-22b, p. 282 10 million _. Years ago H Equator 38 million years ago 55 million years ago INDIAN OCEAN 71 million years ago Fig. 10-23a, p. 283 Before Tip of Indian plate Ancient oceanic crust Indian plate Very old rock, 2 to 2 billion years old Reference point Rising Himalayas Rising Tibetan plateau Reference point Indian plate A 02006 Brooks/Cole - Thomson Fig. 10-23b, p. 283 Positive Positive gravity gravity XA anomaly anomaly Excess mass Expected deflection | o Observed deflection | . of mountains of plumb line Negative of plumb line Negative gravity gravity Mo anomaly anomaly (a) (b) (0 2008 Brooks/Cole - Thomson Fig. 10-24, p. 285 ll Deposition LC e Zo Ds 62006 Brooks/Cole - Thomson Fig. 10-25b, p. 286 (0 2006 Brooks/Cole - Thomson Fig. 10-25c, p. 286 (ANUN IIINA + Folded and fractured rocks have been deformed or strained by applied stresses. + Stress is compression, tension, or shear. Elastic strain is not permanent, but plastic strain and fracture are, meaning that rocks return to their original shape or volume when the deforming forces are removed. + Strike and dip are used to define the orientation of deformed rock layers. This same concept applies to other planar features such as fault planes. + Anticlines and synclines are up- and down-arched folds, respectively. They are identified by strike and dip of the folded rocks and the relative ages of rocks in the cores of these folds. +» Domes and basins are the circular to oval equivalents of anticlines and synclines, but they are commonly much larger structures. + The two structures that result from fracture are joints and faults. Joints may open up but they show no movement parallel with the fracture surface, whereas faulis do show movement parallel with the fracture surface. + Joints are very common and form in response to compression, tension, and shear.