SLO 1

Origin of planet /Ocean Plate Tectonics:

In 1915, Alfred Wegner came up with the concept or idea of a continental drift. This would mean that at one time all of the continents were one (Pangaea), which would mean that there weren't really any land barriers separating the oceans. The one ocean concept is based on the fact that all of the oceans or seas are connected, which forms just one ocean. The ocean is a big part of our planet, not just resource-wise but literally, it takes up 71% of Earth, which is obviously way over half. However, this wasn't always the case. Billions of years ago, the Earth started out as little bits of magnetized space particles. Over time, the pieces got pulled together and started the formation of our planet. This little conglomerate slowly started to expand, which helped it cool down. Theia crashed into Earth, which led to our rotation, but also led to the planet burning. Our moon helped to slow down our rotation. There are four different types of boundaries those four boundaries being divergent, convergent, transform, and plate boundaries. Divergent plates are when the plates pull away from each other, convergent plates are when one of the plates goes under the other. Bathymetry was an early method of monitoring the ocean (erosion and sea level) and was used until the late 1870s. This method included tying and throwing a rope off of a ship until it reached the sea floor. They then pulled this rope up and measured it to see how deep the floor was. Nowadays, instead of using this outdated technique, we use SONAR.

Mid-ocean ridges are where continental crust meets oceanic crust; passive margins are flooded and have active deposition, whereas active margins are too active tectonically with subductions for sediments to accumulate.Epipelagic zone (upper open ocean): 0-650 ft; Mesopelagic zone (middle open ocean): 650-3,300 ft; Bathypelagic zone (lower open ocean): 3,300-13,000 ft; Abyssopelagic zone (abyss): 13,000-20,000 ft; Hadopelagic zone (deep ocean trenches): 20,000+ ft Deposition can be shown by a beach, a narrow, lightly sloping strip of land that lies along the edge of an ocean; a spit, a narrow coastal land formation that is tied to the coast at one end; and a bar, a gap in the coastland with water in it. Coral growth stages consist of reproduction - polyps begin releasing sperm and eggs into the ocean, which then meet and fertilize. Development: Once the eggs fertilize, they soon divide and develop into a larva, which can stay afloat in the ocean for several days, or up to a month, during which it will collect algae to feed upon to grow until the next stage. Settling: Once the larva becomes mature, it will sink into the ocean and attach to the ocean floor or on a reef. It will later become stationary, go through metamorphosis, and turn into a polyp or module. It will then grow and divide to make exact copies to eventually form a colony. Growing: The coral polyp will then continue to grow and develop a mouth and tentacle so that marine algae can attach to it and help the coral in its production of calcium carbonate and encourage calcification. The polyp will then continue to grow even more to form a fully blooming coral. The different types of reefs are Fringing reefs: These grow near the coastlines around islands and continents, separated from the shore by narrow, shallow lagoons. Barrier reefs run parallel to the coastline, separated by deeper and wider lagoons, which can reach the surface of the water, forming a barrier. Atolls - rings of coral that create protected lagoons and are usually located in the middle of the sea. Patch reefs - small, isolated reefs that grow up from the open bottom of an island platform or continental shelf. The four types of estuaries are coastal plain, tectonic, bar built , and fjord. Humans can interfere by creating buildings near the beach, which produce pollution, ,beach nourishment, bypass sediments, create dunes in order to protect property, dredge waterways for commerce and shipping, and create hard structures such as jetties, groins, and seawalls. The sediment classifications are ,boulders, cobbles, ,pebbles ,granules ,very coarse sand, coarse sand, ,medium sand ,fine sand ,very fine sand, ,silt , and clay. The four types of sediment consist of lithogenous sediment, which comes from land either by rivers, ice, and wind, they are found almost everywhere on the ocean floor. Biogenous sediments come from organisms with exoskeletons, shells, teeth, and bones. Typically found in abyssal plains.

Hydrogenous sediments come from chemical reactions in water, found near hydrothermal vents. Cosmogenous sediments come from space either by the filtering in by the atmosphere or carried by meteorites, usually found near meteorite impacts or mixed in with other sediments ([Example] Lithogenous - volcanic sediments, glacial marine sediments, and abyssal clay ,Biogenous - shells of microscopic organisms, sea urchin spikes, pieces of mollusk shells, or coral fragments) The difference between neritic and pelagic is neritic sediments cover ¼ of the seafloor and are found near landmasses, they are shallow water deposits formed closed to land Pelagic sediments are deep water deposits that mostly ooze biogenous sediments and windblown clay, and are deposited slowly. Scientists collect ocean sediments by using surface samples. which can help tell us about the changes in ocean temperature, fossils of animals and how they lived and their surroundings, sea ice extent, and major volcanic activity in the past.

Iceland is sitting on the mid-Atlantic ridge, which is a divergent plate boundary. A divergent plate is a plate that is in the vicinity of another plate; these two are pulling apart, which makes them divergent. When the divergent plates (Eurasian and American plates) pull apart, magma pours up, which results in a new layer of crust in the ocean. As a result of this and those two plates specifically, Iceland itself is being pulled apart in two opposite directions. The location on the mid-Atlantic ridge is not by chance. Iceland is believed to have been created around 25 million years ago, but it started forming around 60 million years ago. The large island sits on the two boundaries , as the plates pull apart and volcanoes erupt . Over time, with enough buildup, it eventually forms land, and as it grows, the island is going to split apart due to the giant rift.