Most marine habitats are formed over a course of thousands of years from the under water as the plates they sit upon move slowly and the climates change! The ocean is geologically formed through a series of volcanoes, tectonic plate movements and time. The world is split into two separate hemispheres the northern which is made of about 61% ocean and southern which is about 80% ocean. The four largest basins in the world are The Atlantic, Indian ocean, and the Arctic ocean. All of the worlds oceans Are connected into a vast system called the World ocean where organisms are able to go from one to another. The ocean surrounding Antarctica is also refereed to as the southern ocean.
The structure of the earth from inside out is inner core, outer core, lower mantle, upper mantle, oceanic crust, and last but not least the continental crust. the earth was sought to be formed millions of years ago by the adopted theory called the "Big Bang" Which was an explosion that created everything. The earth started as a conjugation of small dust and star particles that as they clumped together gravity pulled more and more into itself until taking the shape as our Earth. The internal structure of our planet consists of liquefied iron. The continental vs the oceanic crust is differentiated by the fact that ocean crust is basalt and continental is Granite.
After a long while of tracing volcanic activity, earth quakes, and erosion scientists found that the world and ocean was separated into large lands we call, "Tectonic Plates". In 1620 scientist Francis Bacon concluded that we fit together like puzzle pieces which lead German scientist Alfred Wegner to believe and name that the once large land mass's name was Pangaea. In the late 1950's to the 1960's scientists discovered that the land was divided into the tectonic plates and that they also drifted. The discovery of the Mid ocean ridge was from a survey upon the ocean floor, these surveys were looked upon as subs traversed the ocean looking at the large mountains. Sea floor spreading also resulted in depressions in the ground which were named trenches.
Creation of the Sea Floor: -Rifts form when oceanic crust separates at mid-ocean ridges. -When a rift forms pressure is released from the mantle, causing magma to rise up. -The magma quickly solidifies in the cool water, forming new oceanic crust. -This process continues as the sea floor continues to move away from the mid-ocean ridge. -As you move away from the mid-ocean ridge, the crust is older as well as thicker due to sediment buildup. -The crust and uppermost mantle make up the lithosphere, about 60 miles thick. -The asthenosphere is under the lithosphere, in the upper mantle. -Tectonic plates move at approximately .8-7 inches yearly. -As new lithosphere is created, old lithosphere is destroyed somewhere else. -This occurs at trenches, when two plates collide and one plates dips below the other, creating a subduction zone. -Trenches can occur when two oceanic plates collide, or when an oceanic plate and a continental plate collide. -Oceanic crust last for a few 100 million years, while continental has lasted billions. -An island arc is a chain of volcanic mountains, such as Hawaii. -Shear Boundary- 2 plates move past each other, crust isn't created or destroyed. -Convection- when heat from the Earth's core causes the mantle to swirl. -Alfred Wegener proposed the continents were all together about 200 millions years ago, this mass is called "Pangaea." -Gradually the plates separated and moved to their current locations. -Lithogenous sediment- derived from the physical and chemical breakdown(weathering) of rocks. -Biogenous Sediment- consists of skeletons and shells of marine organisms.
The geological provinces of the ocean *Continental Margins -Continental Shelf- the shallowest part of the margin, only makes up about 8% of the ocean surface, its a gradual slope down and when it ends its called the shelf break -Continental Slope- the closest thing to the edge of the continent, canyons -Continental Rise- sediment deposits accumulates and form deep-sea fans -Active and Passive Margins- continents move different directions depending on what plate there on, those with intense geological activity are called active margin those that aren't are called passive margin *Deep-Ocean Basins -most of the deep-sea floor is at 3000-5000 m - abyssal plain- rises very gradually -abyssal hills- plateaus, rises -seamounts- are submarine volcanoes -guyots- distinctive flattopped seamounts *The Mid-Ocean Ridge and Hydro thermal Vents -central rift valley- material comes up through the ridge and is pulled apart -hydro thermal vents- water is heated by magma and shot up through cracks in the surface -sulfides- by product minerals from hydro thermal vents -black smokers- form near hydro thermal vents, the smoke the emerges is minerals