Chapter 2 Vocabulary.docx

Chapter 2 Vocabulary- Pangaea- In 1912, Alfred Wegener detailed the available evidence and proposed that the continents were originally part of one giant supercontinent. Continental Drift- The continents drifted through the oceanic crust, forming mountains along their leading edges. Mid- Oceanic Ridge- A high standing rift or spreading zone in an ocean. Trenches - An elongated depression in the ocean floor at a sub-duction zone between two tectonic plates and most commonly at the edge of an active continental margin. Seafloor Spreading- Oceanic plates spreading at a rate of 2.5 centimeters per year. Magnetic Field- an area around a magnet in which magnetism is felt. Plate Tectonics- the theory that lithospheric plates that move relative to one another collide in some places, pull apart in others and slide past one another in still others. These movements case earthquakes and volcanic eruptions as well as build mountain ranges. A wide range of data supports the theory. Scientific Method- Is based on logical analysis of data to solve problems. Hypothesis- should always be testable, because science evolves through continual testing with new observations and experimental analysis. Theory- Is when a hypothesis continues to be supported by all available data over a long period of time. Lithosphere- stiff, rigid outer rind of the earth Asthenosphere- the inner, hotter, more easily deformed part of the earth. Isostacy- Buoyancy Mohorovicic Discontinuity (MOHO)- T he boundary between the earth?s crust and mantle has been identified as a difference in density. Low Velocity Zone- is concentrated at the top of the Asthenosphere and may contain a small amount of molten basalt over a zone several hundred kilometers thick. Plates- uneven in size and irregular in shape, the plates fit neatly together like a puzzle. Divergent Boundaries- plates move away from each other at spreading. Convergent Boundaries- plates move toward each other at collision. Sub-duction Zone- Denser plate (Oceanic) will slide down or be sub-ducted into the atmosphere. Transform Boundary- Two plate?s side past each other Triple Junctions- A junction between three lithospheric plates. Spreading Centers- Boundary along which lithospheric plates spread apart or diverge. Rift Zones- An elongated spreading zone in the earth?s lithosphere. Collision Zone- Where two continental plates collide. Hotspot volcanoes- erupt in places remote from any plate boundary. Plumes- Abnormally hot but solid rocks rising within earth?s mantle begin to melt as the rock pressure on them drops. Resurgent Calderas- depressions where the erupting giant volcano collapsed.