Major Features of the Ocean Floor and Continents

can get subducted or buried to make magma again, which starts the cycle. Figure 6 depicts these processes together:

Let's look at the processes in more detail:

Crystallization – this is basically the process of magma hardening into crystals of different kinds. Olivine is a mineral that takes longer to crystallize than quartz. This is why you would have quartz crystals (that are large or small, depending on cooling rates) imbedded in the olivine rock.

Erosion and sedimentation – this is a combination of weathering and layering. Weathering will wear rocks down to smaller pieces known as sediments. Ice, water, and gravity carry sediments from one place to another where they layer out over time and density. Denser deposits sink more deeply but not if a less dense deposit has solidified for another reason. You don't get less rock until the sediment has all become compacted down.

Metamorphism – the term metamorphism just means "change". Heat and pressure can both change rocks in different ways. If a rock has a unique pattern of any kind, metamorphism has likely taken place. Just remember that metamorphic rock is any kind of rock that has changed its characteristics in some way.

MAJOR FEATURES OF THE OCEAN FLOOR AND CONTINENTS

The ocean floor and continents have interesting features that make them different across the world. The ocean floor starts at the continents and then becomes the continental shelf, leading to the continental slope to reach the abyssal plain or flattest section of the ocean floor. Sediment cascades down the continental slope to make it less steep in the area between the continental slope and the abyssal plain. Figure 7 shows these features:

Figure 7.

In the middle of the ocean, you have the mid-ocean ridge, which is like mountains between the continents from bulges and crumpling of the tectonic plates. You also have rift valleys where the ridges have their own valleys between them. Deep trenches are created between tectonic plates that are usually separating. Note that there might be hotspots or volcanic island areas as you see with the Hawaiian Islands. Not all hot spots reach the ocean surface. Abyssal hills and seamounts are where these hotspots have not reached the ocean surface.

The ocean itself is divided into zones according to their features, such as temperature, pressure, amount of salt in the water, and amount and type of sea life. Atop the abyssal plain is the abyssal zone, reaching as far down as 6 kilometers. The hadal zone is the deepest at 6 to 11 kilometers. The term MBSF means "meters below the seafloor", is commonly used to describe these numbers.

Sediment in the seafloor can be of 4 types: The first is the terrigenous sediment, which is stuff coming from the continents, such as from rivers or rainfall. The second is called the biogenous sediment, coming from the shells you see in marine life. The third is called the hydrogenous sediment, coming from materials dissolved within the ocean whenever the conditions change. The last is the cosmogenous sediment that comes from outer space stuff, such as meteors.