The earth's plates move, altering the wind pattern.
A tectonic plate is a piece of the earth's lithosphere. Earth currently has seven to eight major plates. The plates are slowly, but consistently, moving and shifting, and are responsible for geologic occurrences such as volcanism, elevation of land, seismicity, and location of land and bodies of water. Tectonism can also affect other phenomena on earth, such as climate.
Wilson Cycles
Wilson cycles are the cyclic opening and closing of an ocean basin. The stages involved are: Fragmentation, Oceanic Phase, Maximum Dispersal, Subduction Phase and Collisional/Assembly Phase.
Fragmentation involves extensional tectonics -- spreading, internally drained lakes and rift volcanism. The Oceanic Phase is the peak of marine transgression into the continental interior, equable climate, sluggish marine circulation with continental flooding, lower global photosynthesis and rise of CO2 levels. Maximum Dispersal is when the continents are thermally relaxed, sea floor is at maximum age, sea level falls, marine circulation increases and possible glaciation of polar continents occurs. The remaining phases involve the same processes, but in reverse, completing the cycle.
Collisional Tectonics and Mountain Building
According to Gordon Bonan, author of "Ecological Climatology," collisional tectonics also play a role in climate. Mountain building, such as the formation of the Himalayas and the raising of the Tibetan Plateau, caused cooling of the Northern Hemisphere because of the great increase in altitude. These events also led to the development of ice sheets in the Northern Hemisphere over two million years ago. Before that, the global climate was very warm. The final steps to a colder world were the rise of the Tibetan Plateau and the closing of the Isthmus of Panama, which changed ocean circulation.
Volcanoes
Subduction, occurring when one plate pushes under another plate, causes volcanoes to form. The rocks composing the subducting slab undergo dehydration, inducing melting of mantle rock, thereby creating magma. The magma then moves to the surface through a conduit and erupts onto the surface, forming a volcano.
Ocean Currents
Currents are affected by the ocean floor as well as the continents around which they flow. Ocean currents operate by thermohaline circulation. This means that warmer water flows at the top of the ocean. Cold water sinks to the bottom, and as the temperature of water changes, it will convect to get back to these positions. Plate tectonics change the location of the continents, changing the way the currents move around them.
Tags: marine circulation, Maximum Dispersal, Northern Hemisphere, Oceanic Phase, Tibetan Plateau
