Plate Tectonics PDF

 BELLO! Plate Tectonics Introduction to "Plate Tectonics" Plate tectonics is a theory that explains how Earth's landforms are created through underground movements. The heat from radioactive processes within the planet’s interior causes the plates to move, sometimes toward and sometimes away f...

 BELLO! Plate Tectonics Introduction to "Plate Tectonics" Plate tectonics is a theory that explains how Earth's landforms are created through underground movements. The heat from radioactive processes within the planet’s interior causes the plates to move, sometimes toward and sometimes away from each other. This movement is called plate motion, or tectonic shift..  Plate Tectonics The lithosphere is the solid, outer part of Earth. The lithosphere includes the brittle upper portion of the mantle and the crust, the outermost layers of Earth's structure. It is bounded by the atmosphere above and the asthenosphere (another part of the upper mantle) below. The Earth's lithosphere is divided into about a dozen plates, which move over the weaker asthenosphere. Plates are created and recycled, creating and destroying each other. Continents in the The asthenosphere, from the Greek word asthenes meaning "weak", is a portion of the lithosphere drift with the plates. Earth's mantle that flows like molten plastic despite being solid. Continental Drift Theory & Evidences Continental drift refers to the large-scale horizontal movements of continents relative to each other and ocean basins during geologic time. This concept was a precursor to plate tectonics and has a long history. German naturalist Alexander von Humboldt theorized in 1800 that the lands bordering Atlantic Ocean had once been joined. French scientist Antonio Snider-Pellegrini later argued that the presence of identical fossil plants in North American and European coal deposits could be explained by a previously connected relationship. Continental Drift Theory & Evidences In 1915, Alfred Wegener, a German meteorologist, further developed this theory in his book, highlighting the similarities in rocks, structures, and fossils on opposite sides of the Atlantic. Wegener suggested the existence of a supercontinent called Pangaea that later split into the continents we see today. A sea called Tethys divided the Pangaea into two huge landmasses: Laurentia (Laurasia) to the north and Gondwanaland to the south of Tethys. Continental Drift Theory & Evidences Proponents of the drift theory pointed to geological evidence such as geographic alignment, rock ages, and structures on opposite sides of the Atlantic. Fossil and climate data also supported the concept, with identical fossils found in Africa and South America suggesting a past connection. Evolutionary similarities in plants and animals further supported the theory, with rocks from ancient glaciers distributed across southern continents indicating a shared history. The idea of Gondwanaland and a continental glacier explained these findings, supporting the continental drift hypothesis. Sea Floor Spreading and Drifting Continents Wegener's idea of continents floating on the oceanic crust and being dragged by tidal forces was quickly dismissed as tidal forces were deemed too weak to cause such movement. However, a breakthrough occurred when scientists realized that convection in Earth's mantle could push and pull continents apart, leading to the creation of new oceanic crust through seafloor spreading. Sea Floor In 1928, Arthur Holmes suggested that convection currents caused the Spreading and continents to separate, resulting in mountain building and ocean floor development. Evidence supporting this theory emerged post-World War II Drifting through the exploration of the seafloor. The discovery of the Mid-Atlantic Ridge and rift valleys on the ocean floor, coupled with the concentration of Continents earthquakes near these rifts, indicated tectonic activity. Further investigations revealed similar features in the Pacific and Indian oceans. Seafloor Spreading Hypothesis In the early 1960s, Harry Hess and Robert Dietz proposed that the crust separates along the rifts in mid-ocean ridges and that new seafloor forms by upwelling of hot new crust into these cracks. The new seafloor—actually the top of newly created lithosphere—spreads laterally away from the rift and is replaced by even newer crust in a continuing process of plate creation. Sea Floor Spreading and Drifting Continents In 1965, Canadian geologist J. Tuzo Wilson introduced the concept of tectonic plates moving on Earth's surface. He identified three main types of plate boundaries - divergent, convergent, and transform. Scientists later found that most tectonic activity occurs at these boundaries, where rocks are folded, faulted, or compressed. They analyzed the rates and directions of plate movements, confirming a model of rigid plates on Earth's surface. By 1968, plate tectonics was established, widely accepted by 1970, leading to revisions in textbooks and new scientific fields. Types of Plate Boundaries Divergent Boundary At divergent boundaries, plates move apart and a new lithosphere is created (plate area increases).  Convergent Boundary Plate movements on Earth are balanced, with separation in one area leading to convergence elsewhere to maintain surface area. These interactions create convergent boundaries, where plates collide and cause complex geological events. Convergent boundaries are known to be the most intricate type of plate boundary.  Types of Convergent Boundaries Oceanic-Oceanic Convergence In ocean-ocean convergence, two oceanic plates converge or collide. The denser plate subducts into the asthenosphere below the convergence zone. Trenches are formed at the surface of ocean-ocean convergence. The location where the sinking of a plate occurs is called a subduction zone. Oceanic-Continental Convergence When oceanic lithosphere and continental lithosphere collide, the dense oceanic lithosphere subducts beneath the less dense continental lithosphere. An accretionary wedge forms on the continental crust as deep-sea sediments and oceanic crust are scraped from the oceanic plate.  Continental-continental convergent boundaries occur when two continental plates move towards each other. Both plates are less dense, so neither subducts under the other. Instead, the plates collide and push upwards forming large mountain ranges. Continental-Continental Convergence  Transform Boundary Transform faults are boundaries where plates slide past each other, with no creation or destruction of lithosphere. Philippine Tectonism The Philippines' geology is dominated by subduction tectonics, creating a seismically active region known as the Philippine Mobile Belt. It is surrounded by subduction zones where oceanic plates converge towards the archipelago, leading to deep trenches like the Philippine and Manila Trenches. The area is also intersected by the left-lateral strike-slip fault called the Philippine Fault. This tectonic activity causes volcanic eruptions, earthquakes, and tsunamis, making the Philippines highly vulnerable to geological hazards. The region's complex tectonic setting is the result of plates converging from multiple directions, shaping the landscape over time. The Philippines is a prime example of geology shaping the land and impacting the local population.  Philippine Sea Plate The Philippine Sea Plate is an oceanic plate moving northwest towards the Eurasian Plate at a speed of 6-8 cm per year. The convergence rate increases southwards along the trench. The plate rotates near the triple junction of the Philippine Sea, Eurasian, and Pacific Plates at the northern tip of the Philippine Sea Plate, rotating about 0.5˚ per million years. It has rotated approximately 90˚ since the early Tertiary period. Plate motion has been relatively constant for 3-5 million years, although some studies suggest a change in direction around 1 million years ago.  Philippine Mobile Belt The Philippine Mobile Belt, also known as the Taiwan-Luzon-Mindoro Mobile Belt, is a complex tectonic zone located where the Eurasian Plate, Philippine Sea Plate, and Indo-Australian Plate converge. This belt spans the entire Philippine archipelago and stretches southwards to the Molucca Sea and eastern Indonesia, experiencing frequent earthquakes and active volcanism. Bounded by east-dipping subduction at the Manila Trench, Negros Trench, Sulu Trench, and Cotabato Trench, as well as west-dipping subduction at the Philippine Trench and East Luzon Trough, it is considered an "independent block" or "microplate" in the region. While it has connections to the Eurasian Plate and Philippine Sea Plate, defining its exact tectonic boundaries is challenging due to the influence of the Philippine Fault, a strike-slip fault that runs through the mobile belt.  Active zones in the Philippine Mobile Belt The Philippine Mobile Belt has two active zones: the western active zone, bounded by east-dipping subduction zones like the Manila Trench, and the eastern active zone, bounded by west-dipping subduction zones like the Philippine Trench. Positioned between the Eurasian Plate and the Philippine Sea Plate, the belt undergoes east-west compression, leading to fold and thrust zones.  Philippine Fault Zone The Philippine Fault is a left-lateral strike-slip fault that runs from northern Luzon to Mindanao, parallel to the Philippine Trench. It plays a key role in the geodynamics of the region and has an average velocity of 0.5 cm per year, although other models suggest velocities of 2-3 cm per year. It is estimated to have formed between 2-4 million years ago and extends to the northeast of Halmahera. The fault is significant in controlling the movement within the Philippine Trench system. Shear Partitioning Mechanism Palawan Microcontinental Block  Manila trench The Philippine Mobile Belt has two active zones: the western active zone, bounded by east-dipping subduction zones like the Manila Trench, and the eastern active zone, bounded by west-dipping subduction zones like the Philippine Trench. Positioned between the Eurasian Plate and the Philippine Sea Plate, the belt undergoes east-west compression, leading to fold and thrust zones. Luzon Volcanic Arc Philippine Trench The Philippine Trench is formed by the westward subduction of the Philippine Sea Plate under the Philippine Mobile Belt. It stretches from southeastern Luzon to northeast of Halmahera, covering a total distance of 1,800 km with a maximum depth of 10,540 meters. Connected to the East Luzon Trough, it features an east-dipping subduction zone and an east–west trending strike-slip fault. Formation of the Philippine Trench The Bathymetric profile of the Philippine Trench shows that it is deepest around 10˚N in the middle and becomes shallower towards the north and south. The trench was formed by recent subduction, as indicated by the shallowness of the subduction slab and the subduction rate. One hypothesis suggests that the trench was created due to the collision of the Palawan Block with the Philippine Mobile Belt, serving as a stress outlet resulting from the collision. This led to the development of a subduction zone. Formation of the Philippine Archipelago Tectonic Hazards Volcanoes The Philippine archipelago is bounded by subduction zones which makes the region volcanically active. The most active volcano in the Philippines is the Mayon Volcano located in southeastern Luzon. It is related to the subduction of the Philippine Sea Plate beneath the Philippine Mobile Belt. Volcanoes in the Philippines Earthquakes The Philippines is seismically active due to its location on the Philippine Mobile Belt. Faults and subduction zones cause frequent earthquakes, with the Philippine Trench being the most active. The majority of earthquakes are shallow, as the trench is a young subduction system. Earthquakes (mag >6.0) in the Philippines (2019) Blue circles indicate magnitude 6.0–6.9 Green circles indicate magnitude 7.0–7.9 Orange circles indicate magnitude above 8.0 In conclusion: The theory of plate tectonics has significantly improved our understanding of Earth's dynamic crust, revealing mechanisms like continental drift, sea-floor spreading, and plate boundaries. The Continental Drift Theory, proposed by Alfred Wegener, uses fossil correlations, geological formations, and continental coastline fit to understand continents' movement over time. Sea-floor spreading demonstrates new oceanic crust at mid-ocean ridges, reinforcing continents' constant motion. The categorization of plate boundaries into divergent, convergent, and transform boundaries provides insights into geological phenomena like earthquakes, volcanic activity, and mountain building. The Philippine archipelago, located at the convergent boundary of several tectonic plates, is a prime example of plate tectonics, characterized by seismic activity and volcanic eruptions, highlighting the ongoing impact of these forces. Meet the FGD Francis Francis is known for his brainy and playful nature, making him the genius of the Minions. Gwin As the leadership-driven Minion, Gwin takes charge during their adventures. Dan The youngest and most innocent Minion, Dan's enthusiasm often leads to comical situations. TANK YU! Type BANANA if the statement is true otherwise, type your crush’s name if false: 1. Convergence boundary is when the plates slide past each other. FALSE 2. Mountain ranges are formed through continental-continental convergence. TRUE 3. The lithosphere is the solid, outer part of Earth. The lithosphere includes the brittle upper portion of the mantle and the crust, the outermost layers of Earth's structure. TRUE 4. The Philippine Mobile Belt has two active zones: the western active zone and the eastern active zone. TRUE 5. Arthur Holmes and Alfred Wegener proposed that the crust separates along the rifts in mid-ocean ridges and that new seafloor forms by upwelling of hot new crust into these cracks. FALSE  SOURCES: https://earthguide.ucsd.edu/eoc/teachers/t_tectonics/p_pangaea2.html#:~:text=When%20Pangaea%20broke%20up%2C%20 the%20northern%20continents%20of,Laurasia%20and%20the%20southern%20continent%20is%20called%20Gondwanalan d https://oceanservice.noaa.gov/facts/tectonics.html#:~:text=The%20heat%20from%20radioactive%20processes,plate%20mo tion%2C%20or%20tectonic%20shift. https://en.wikipedia.org/wiki/Convergent_boundary#:~:text=volcanic%20island%20arcs.-,Continental%20%E2%80%93%20o ceanic%20convergence,scraped%20from%20the%20oceanic%20plate. https://www.academia.edu/11376392/Understanding_Earth_Fifth_Ed_ https://en.wikipedia.org/wiki/Subduction_tectonics_of_the_Philippines#:~:text=The%20subduction%20tectonics%20of%20t he,each%20other%20in%20multiple%20directions. https://byjus.com/ias-questions/what-is-ocean-ocean-convergence/#:~:text=In%20ocean%2Docean%20convergence%2C%2 0two,is%20called%20a%20subduction%20zone. https://study.com/academy/lesson/convergent-boundary-definition-facts-examples.html#:~:text=Continental%2Dcontinental %20convergent%20boundaries%20occur,upwards%20forming%20large%20mountain%20ranges. https://www.britannica.com/science/continental-drift-geology Slide Chef