Earth's processes

• The process of mountain building is called orogenesis, mountains are formed when forces change the Earth's crust
• Volcanoes form at divergent plate boundaries where magma rises to the surface through fissures in the Earth's crust
• When mountains aren't volcanic it is because plates collide head on and push upwards
• When they are volcanic it is because one plate subducts the other letting magma flow through the cracks forming a volcanic mountain
• Volcanic mountain - Mt. Kilimanjiro
• An extinct volcano by definition is a dead volcano, which has not erupted in the last 10,000 years and is not expected to ever erupt again
• Mt. Thielsen/Big cowhorn eruptive activity ceased 250,000 years ago
• Without volcanoes, most of Earth's water would still be trapped in the crust and mantle
• Geoscientists continue to debate two competing theories, but, recent research has strengthened that water was always present in the rocks of the Earth's mantle and was gradually released to the surface through volcanoes
• All this evidence suggests that the Earth's surface water is stored in the Earth's mantle in the form of hydroxyl groups trapped within minerals such as ringwoodite and is released as vapour through volcanoes and is 1.5% weight water.
• The ocean is the body of salt water which covers approximately 71% of the surface of the Earth
• More than 80% of the our ocean is unmapped, unobserved, and unexplored
• Given the high degree of difficulty and cost in exploring our ocean using underwater vehicles, researchers have long relied on technologies such as sonar to generate maps of the seafloor
• Seafloor or Ocean floor is the literal floor of the ocean also known as "Sea bed"
• Ocean basin is when the water has covered a large portion of the Earth's crust
• Major ocean basins: Pacific Ocean, Atlantic Ocean, Indian Ocean, Southern Ocean, Arctic Ocean
• The first modern breakthrough in seafloor mapping came with the use of underwater sound projectors called "sonars", which was first used in World War I
• Harry Hess was a geologist and Navy submarine commander during World War II, part of his mission was to study the deepest part of the ocean floor
• The beginning of WWII marked the start of extensive research in underwater acoustics
• The rapid advancement of underwater acoustics continued after WWII, with wartime developments leading to large-scale investigations of the ocean's basins.
• In 1946, Harry Hess discovered that hundreds of flat-topped mountains (guyot) shaped the Pacific floor
• Hess proposed in 1960 that the movement of the continents was a result of seafloor spreading
• In 1962, Hess added a geologic mechanism to account for Wegener's moving continents that broke the once-joined continents into the seven with which we are familiar
• Seafloor Spreading is the process that continually adds new material to the ocean floor while pushing older rocks away from the ridge
• Magma cools as it reaches the surface and forms new rock called Basalt
• Basalt is denser than water so it sinks downwards towards the bottom of the ocean
• As magma moves up through the mantle, it melts the surrounding rock creating a plume of hot molten rock
• Plumes can be found at mid-ocean ridges where they create volcanism on the sea floor
• The Mid Atlantic Ridge runs through the Atlantic Ocean and is where magma pushes up from below the crust
• Constructive Plate Boundary occurs when two plates move apart from one another
• Mid Atlantic Ridge is an example of constructive plate boundary
• At Mid Ocean Ridges, there is volcanism and earthquakes because they are areas of high stress
• Subduction zones are examples of destructive plate boundaries