Endogenic Processes PDF

ENDOGENIC PROCESSES Week 7: EARTH AND LIFE SCIENCE 11 ENDOGENIC PROCESSES en·do·gen·ic /endōˈjenik/ Adjective, GEOLOGY Formed, located or occurring beneath the su ace of the ea h. E ND O G E NI C PRO C E S S E S a re g e ol og i c a l processes that occur beneath the sur fa ce of...

ENDOGENIC PROCESSES Week 7: EARTH AND LIFE SCIENCE 11 ENDOGENIC PROCESSES en·do·gen·ic /endōˈjenik/ Adjective, GEOLOGY Formed, located or occurring beneath the su ace of the ea h. E ND O G E NI C PRO C E S S E S a re g e ol og i c a l processes that occur beneath the sur fa ce of the Ear th. It is associated with energy originating in the interior of the solid ea h. T he ground we live on is moving all the time. T h e forces within the ear th that cause the ground to move are called ENDOGENIC FORCES.  TYPES OF ENDOGENIC PROCESSES 01 02 DEFORMATION METAMORPHISM (FOLDING & FAULTING) 05 03 04 VOLCANISM HEAT IN EARTH’S MAGMATISM INTERIOR  01 METAMORPHISM METAMORPHISM is the process of changing materials that make up the rock. It is an endogenic pro c es s t h a t o c c ur s wh en there are pressure and heat applied to geologic structures which leads to the formation of Metamorphic Rocks.  02 DEFORMATION Deformation d es c rib es the process by which rocks are folded and COMPRESSION faulted. (FOLDING) Rocks become deformed when the E ar th ’s c ru st i s c om p re s s e d or stretched. T h e forces needed to do this TENSION ac ti vi ty ove r m i lli ons of ye ars – deformation is a ve slow process. SHEAR Stress is the force applied to an object. In geology, stress is the force per unit area that is placed on a rock. Four CONFINING types of stresses acting on materials.  COMPRESSION FOLDING It is the push or Anticlines and synclines are the up and down folds that usually squeeze against one occur together and are caused another where the by compressional stress. stress produced is Anticlines are folds in which directed towards the each half of the fold dips away center and the crust from the crest. Synclines are becomes sho er and folds in which each half of the fold dips toward the trough of thicker, building the fold. mountain ranges like is intensely folded limestone Alps or Himalayas. from Highland County shows how anticlines and synclines  TENSION It occurs as tectonic plates a re p u l l e d a p a r t a n d c r u s t becomes thinner. Rocks near to t h e s u r fa c e b e c o m e f a u l t e d , sometimes producing rift valleys. It re f e rs to stre s s w hi c h stretches rocks in two opposite d i re c ti ons. T h e roc ks b e c om e longer in a lateral direction and thinner in a ve ical direction  SHEAR SHEARING - some of the por tions of a plate at the edge m a y b re a k a w a y i n d i f fe re n t directions. Eventually making the plate smaller inside. When forces are parallel but moving in opposite directions, the stress is called shear. Shear stress i s the m ost c om m on stre s s at transform plate boundaries.  FAULTING It is the fracturing and displacement of more brittle rock strata along a fault plane either caused by tension or compression. A NORMAL b re ak i n roc k along w hi c h a ve r ti c al or horizontal rock movement has occurred is FAULT called a fault. REVERSE e line of fault which appears on the FAULT land sur face is known as a fault line. T h e se STRIKE-SLIP lines are often lines of weakness that allow FAULT the molten rock to rise onto the Ear th ’s sur face when there is active volcanic activity nearby.  TYPES OF FAULTS NORMAL REVERSE TRASNCURRENT FAULTS FAULTS OR STRIKE-SLI[P form when the hanging form when the hanging have walls that move wall drops down. T h e wa l l m ov e s u p. T h e sideways, not up or f orce s t ha t cre a t e forces creating reverse down. normal faults are pulling f a u l t s a r e full of iron oxide dust t h e s i d e s a p a r t, o r compressional, pushing extensional. the sides together.  HEAT IN EARTH’S INTERIOR PRIMORDIAL RADIOACTIVE HEAT HEAT Heat generated during Heat generated by long-term ea h’s formation radioactive decay. CONVECTION and CONDUCTION MAGMATIS M MAGMATISM It happens when magma generated and develops into igneous rocks. Where does the magma form? 1. Mid-oceanic ridges 2. Mantle plumes 3. Subduction zones It is one of the most impo ant a subduction zone is a spot geological processes, forming a where two of the planet's dense, low-lying, igneous crust tectonic plates collide and that oors the vast ocean basins, one dives, or subducts, making up the solid rocks over MANTLE beneath the other nearly two-thirds of the Ea h’s su ace. PLUMES MID–OCEANIC SUBDUCTIO some intraplate volcanoes and large RIDGES igneous provinces (LIPs) in N ZONES continental areas may originate from hydrous mantle upwelling (i.e. a plume) from the mantle transition zone (MTZ) at 410–660 km depths in the Ea h’s deep interior. VOLCANIS M It is the phenomenon of eruption of molten rock (magma) onto the sur face of the Ear th or a solid-sur face planet or moon, where lava, pyroclastics, and volcanic gases erupt through a break in the su ace called a vent. It includes all phenomena resulting from and causing magma within the crust or mantle of the body, to rise through the crust and form volcanic rocks on the su ace. EFFUSIVE ERUPTION EXPLOSIVE ERUPTION EFFUSIVE ERUPTION A n e f fu s i ve e r u p t i o n i s a t y p e of volcanic eruption in which lava steadily ows out of a volcano onto the ground. For a n ef fus i ve erup ti on to occur, magma must be permeable enough to allow the ex p ulsi on of g as b ub b les contained within it. EXPLOSIVE ERUPTION An explosive eruption always begins wi th s ome form of b lock ag e i n the crater of a volcano that prevents the releas e of g as es trap p ed i n hi g hly viscous andesitic or rhyolitic magma  OF WEEK 7