.assignment 1 Science.

05 Joseph Kowalski August 6,2009

1-6 Blessed Noli Evan C. Arligue

convergent boundary - also known as a destructive plate boundary (because of subduction), is

an actively deforming region where two

(or more) tectonic plates or fragments of lithosphere move toward one another and collide. As a result of pressure and friction and plate material melting in the mantle, earthquakes and volcanoes are common near convergent boundaries. divergent boundary -(also known as a constructive boundary or an extensional boundary) is a linear feature that exists between two tectonic plate that are moving away from each other. These areas can form in the middle of continents but eventually form ocean basins. transform boundary -also known as conservative plate boundary, is a fault which runs along the boundary of a tectonic plate. The relative motion of such plates is horizontal in either sinistral or dextral direction. Typically, some vertical motion may also exist, but the principal vectors in a transform fault are oriented horizontally. Not all faults are transform faults, and not all plate boundaries are transform faults. subduction -is the process that takes place at convergent boundaries by which on tectonic plate moves under another tectonic plate, sinking into the

Earth's mantle, as the plates converge. A subduction zone is an area on Earth where two tectonic plates move towards one another and subduction occurs. Rates of subduction are typically measured in centimeters per year, with the average rate of convergence being approximately 2 to 8 centimeters per year (about the rate a fingernail grows)[1]. mid-ocean ridge -is an underwater mountain range, typically having a valley known as a rift running along its spine, formed by plate tectonics. This type of oceanic ridge is characteristic of what is known as an oceanic spreading center, which is responsible for seafloor spreading. The uplifted sea floor results from convection currents which rise in the mantle as magma at a linear weakness in the oceanic crust, and emerge as lava, creating new crust upon cooling. A mid-ocean ridge demarcates the boundary between two tectonic plates, and consequently is termed a divergent plate boundary. continental crust – the continental crust is much lighter and thicker oceanic crust. It is about 30 km. in thickness. oceanic crust – is denser than continental crust. This is between 5 & 8 km. in thickness. mountain range - is a chain of mountains bordered by highlands or separated from other mountains by passes or valleys. Individual mountains within the same mountain range do not necessarily have the same geology, though they often do; they may be a mix of different orogeny, for example volcanoes, uplifted mountains or fold mountains and may, therefore, be of different rock. The Himalaya mountain

range contains the world's highest mountains on the Earth's surface; the highest of which is Mount Everest. The Andes is the world's longest mountain range on the Earth's surface. The longest mountain range is actually the Mid-Atlantic Ridge, which runs down the middle of the Atlantic Ocean. The Arctic Cordillera is the world's northernmost mountain system and contains the highest point in eastern North America. earthquake - the sudden release of energy in the form of seismic waves as a result of plate movements.