Science 10: Plate Tectonics PDF

REVIEWER IN SCIENCE 10 LESSON: CONTINENTAL DRIFT THEORY  Alfred Wegener - German Meteorologist - Originator of the theory of continental drift  Pangaea – super continent TWO PARTS OF PANGAEA: 1. Laurasia – Northern hemisphere (upper) 2. Gondwana – Southern h...

REVIEWER IN SCIENCE 10 LESSON: CONTINENTAL DRIFT THEORY  Alfred Wegener - German Meteorologist - Originator of the theory of continental drift  Pangaea – super continent TWO PARTS OF PANGAEA: 1. Laurasia – Northern hemisphere (upper) 2. Gondwana – Southern hemisphere (lower)  Panthalassa – super ocean PIECES OF EVIDENCE:  Fits of the continents  Similarities of fossils in continents  Mesosaurus – a freshwater reptile that can be found in South America and Africa.  Cynognathus – a triasic land reptile that can be found in South America and Africa.  Glossopteris – a fern that can be found in Australia, Antarctica, India, Africa, and South America.  Lystrosaurus – a triasic land reptile that can be found in Antarctica, India, and Africa.  Similarity of rock type and age  Continuity of geologic features from continent to continent  Paleo climate data  Glacial Striations – scratches left by the moving glaciers. LESSON: THEORY OF PLATE TECTONICS  Plate Tectonic -The Earth’s crust is divided into plates which are moved in various direction. -The word “tectonic” refers to the deformation of the crust as a consequence of plate interaction. -Made up of rigid lithosphere.  Lithosphere – A single solid layer made up by the crust and mantle of Earth. SEVEN MAJOR PLATES: 1. Eurasian Plate 2. Indo-Australian Plate 3. Pacific Plate 4. Antarctic Plate 5. North American Plate 6. South American Plate 7. African Plate EVIDENCE FOR PLATE TECTONICS:  Africa and South America -There is a remarkable similarity in the shape of the west coast of Africa and the east coast of South America.  Earthquakes and Volcanoes -Earthquakes and volcanoes occur in boundaries between plates.  Heat flow and Seafloor Elevation -Heat flow at plate boundaries provides evidence of convection currents in the asthenosphere.  Plate Boundary – The place where two plates meet.  Trench – A very deep depression in the ocean floor.  Island Arcs – Long chains of active volcanoes with intense seismic activity. REVIEWER IN SCIENCE 10 TYPES OF PLATE BOUNDARIES: 1. Divergent Boundary – A feature that exists when two tectonic plates move away from each other. 2. Convergent Boundary – A feature that exists when two tectonic plates move toward each other. a. Oceanic-Oceanic Convergence – One of the two plates is descending beneath the other. This process is called subduction. b. Oceanic-continental Convergence– The oceanic plate is descending beneath the continental crust. Subduction does not happen. 3. Transform Boundary – Are places where plates slide sideways past each other. LESSON: MECHANISMS OF PLATE MOTION  DRIVING FORCE - either push tectonic plates toward one another or pull them apart.  Slab Pull – This force occurs as a subducting plate sinks into the hot mantle beneath it.  Slab (trench) Suction – This force occurs between two colliding plates where one is subducting beneath the other.  Ridge Push – Gravitational force that causes a plate to move away from the crest of an ocean ridge, and into a subduction zone.  RESISTING FORCE – act against the driving forces of plate tectonics.  Slab Resistance – This force acts as a plate collides with another plate boundary.  Collisional Resistance – This force directly opposes the slab pull force. It occurs as the heavy basaltic plate is pulled down into the mantle.  Transform Fault Resistance – Between two off-set spreading centers, the plates move past one another forming transform faults.  Drag Force / Basal Drag – The resistance force caused by the motion of a body through a fluid, such as water or air.  Mantle Convection – The very slow creeping motion of Earth’s solid silicate mantle caused by convection currents carrying heat from the interior to the planet’s surface. LESSON: TYPES FOLDS AND FAULTS  Fault – A fracture or zone of fractures between two blocks of rock. TYPES OF FAULT:  Normal Fault –Faults that result from horizontal tensional stresses in brittle rocks and where the hanging-wall block has moved down relative to the footwall block.  Horsts & Grabens – Due to the tensional stress responsible for normal faults, they often occur in a series, with adjacent faults dipping in opposite directions.  Half-Grabens – A normal fault that has a curved fault plane with the dip decreasing with depth can cause the down-dropped block to rotate.  Reverse Fault – Faults that result from horizontal compressional stresses in brittle rocks, where the hanging wall block has moved up relative the footwall block.  Thrust Fault – Special case of reverse fault where the dip of the fault is less than 15 degrees.  Strike-Slip Fault – Faults where the relative motion on the fault has taken place along a horizontal direction.  Transform Faults – Plate boundaries along which two plates slide past one another in a horizontal manner.  Folds – These are when rocks deform in a ductile manner, instead of fracturing to form faults, they may bend of fold. REVIEWER IN SCIENCE 10 TYPES OF FOLDS Monoclines occur when Monocline horizontal strata are bent upward so that the two limbs of the fold are still horizontal. Anticline are folds where the originally horizontal Anticlines strata has been folded upward, and the two limbs of the fold dip away from the hinge of the fold. Synclines are folds where the originally horizontal strata have been folded Synclines downward, and the two limbs of the fold dip inward toward the hinge of the fold. CLASSIFICATION OF FOLDS