Tectonic Forces And Processes PDF

 Objectives Identify the three types of plate movements from a short excerpt. Expound three types of plate movement based on plate tectonics theory using an illustration. Cite specific examples of land forms as outcomes of plate movement.  Tectonic Forc...

 Objectives Identify the three types of plate movements from a short excerpt. Expound three types of plate movement based on plate tectonics theory using an illustration. Cite specific examples of land forms as outcomes of plate movement.  Tectonic Forces and Processes -Deformation refers to any change in the shape or size of a rock as a response to stress. The deformation may occur by either folding or faulting. -Folding in rocks occurs when they are subjected to tectonic forces from opposite sides. -Compressional stress causes squeezing -Tensional stress causes stretching -Shearing stress causes side- to-side movement. -If there are no movements on either side of the fracture, it is called joint -If there is any movement on one or both sides of the fracture, it is called a fault. -Faulting is the result of the fracture or displacement of rock layers or strata along a fault plane.  Dip-slip faults Dip-slip faults show vertical movement of the hanging wall and the footwall. Examples of dip-slip faults are the normal fault (caused by tension) and reverse fault (caused by compression.)  Strike-slip faults Strike-slip faults shows horizontal and parallel displacements of the fault planes Examples of dip-slip faults is transform fault, which is caused by shear stress.  Plate Motion 14  How the continents originated has been a major debate in geology The 19th century geologist James Dwight Dana proposed the continent accretion theory, which proposed that the continents have always been stationary, with the gradual addition of new material around a central nucleus. Continental Assimilation Theory, explained how the ocean areas accumulated the denser elements, then subsided to form basins. In, 1925 the expanding Earth hypothesis stated that the present continents split apart with the expansion of Earth, and that the continents combined could never half of the current Earth’s surface area. 15  t i n e n t a l C o n f t T h e o r y Dri Continental Drift is the gradual movement of the continents over time. The upper layer of the crust is broken down into large slabs called plates, which sit on a fluid level of molten rock. 17 Alfred Wegener theorized that the continents once existed as a single landmass, which he called Pangaea. Example: South America corresponds to the western coast of Africa. 18 Paleomagnetism: As new oceanic crust cools, it acquires the magnetic orientation of the Earth’s field, creating alternating stripes of normal and reversed polarities. 19 Plate Tectonics and Plate Movements 20  SEVEN MAJOR PLATES African Plate Antarctic Plate Eurasian Plate Indo-Australian Plate North American Plate Pacific Plate South American Plate 21  SEVEN MINOR PLATES Arabian Plate Caribbean Plate Cocos Plate Juan de Fuca Plate Nazca Plate Philippine Plate Scotia Plate 22  Divergent Boundary ◦ Occurs when two tectonic plates move away from each other ◦ Frequent earthquakes strike along the rift. ◦ At divergent boundaries, oceanic crust, made of basalt, is created. 23  Convergent Boundary ◦ When two plates come together. ◦ As two plates collide, one or both buckles into a rugged mountain range or bends into a deep seafloor trench. ◦ Powerful earthquakes occur around wide areas on both sides of the boundary. 24  Transform Boundary ◦ Two plates sliding past each other. ◦ Natural or humanmade structures that cross a transform boundary are offset-split into pieces and carried in opposite directions. 25  Seafloor Spreading 1. Seafloor spreading is a geologic process in which tectonic plates split apart from each other as a result of mantle convection – the slow, churning motion of the Earth’s mantle. 27 28 29 30 The basaltic rocks that make up most of the new oceanic crust is fairly magnetic substance. Using magnetometers, scientists discovered that the magnetism of the ocean floor around mid- ocean ridges was divided into matching “stripes” on either side of the ridge. 31 Oceanic crust moves away from mid-ocean ridges. As it moves, it becomes cooler, denser, and thicker. 32 33 Geographic features can form through seafloor spreading. For example, the red sea was created as the African Plate and Arabian Plate moved away from each other. 34 Today, only the Sinai Peninsula connects the Middle East to North Africa. Geologists predict that seafloor spreading would eventually separate the two continents and join the Red and Mediterranean Seas 35 Subduction happens when tectonic plates crash into each other instead of moving apart. 36 Thank You! CREDITS: This presentation template was Slidesgo Freepik infographics and images by Freepik Flaticon created by Slidesgo, including icons by Flaticon,