8The earths crust of course! Composed of the igneous rock basalt
9Oceanic Crust is made of one type of rock: igneous basalt 7 km (5 miles ) thinComposed of dark, igneous rockBasalt (black, ocean basin)3.0 g/ml density180 million years young (or less)
10What does the ocean crust look like? touring the ocean floor
11How do they know what’s under all that water??? 23.1How do they know what’s under all that water???Video clip Mapping the Ocean Floor(mapping California coast)(coral reef)Geode CD-ROM and note sheetES0802 “How Old is the Atlantic Ocean?”
12Oceanic Crust is the same as the continental crust: it has mountains, canyons, hills, valleys ridges, plains …
17U.S. East coast has a very wide PASSIVE continental shelf On your map,find and shade passive continental marginsturquois blue.
18Gulf of Mexico has passive margins consisting of MILES of continental shelf and shallow seas
19Continental shelfEast coast of S. America Australia
20Where does the continent stop and the ocean floor begin?? The continental shelf and continental slope are attached to the continent,Where as the sediments of the continental rise sits on the ocean floor.
21Often there is a steep, deep drop off at the edge of the continental shelf to the ocean floor.
22Abyssal plains Are extremely level. They are the flattest places on earth!cover about one-half of the deep-ocean floor.The flatness of these plains is the result of the accumulation of a blanket of sediments, up to 5 kilometers thick!(which overlies the basaltic rocks of the oceanic crust.)
23Abyssal plains are large flat basin with little of no slope Abyssal plains are large flat basin with little of no slope. The rugged ocean floor is filled-in and smoothed by layers and layers of sediment.
24Just as a heavy snowfall covers all the features of the street, Sediment covers all the rugged features on the ocean floor smoothing it flat
25Thousands of seamounts dot the ocean floor Thousands of seamounts dot the ocean floor. Sea mounts = under the sea volcanic mountainsSmaller hills punctuate the abyssal plains are most common in theAtlantic Ocean
26The Hawaiian Island arc are part of a long chain of seamounts that stick out above the water in the Pacific Ocean
27Ocean ridges rise above the ocean floor and contains many faults and fractures.
28At mid-ocean ridges volcanic vents spew smoke and hot gases, and heat the surrounding water where a few types of marine life can survive and flourish.Hydro-thermal ventshttps://www.youtube.com/watch?v=XotF9fzo4Vo
29Where are the sandy beaches and shallow water? Instead, steep, rocky slopes
30Mountains and volcanoes are found along ACTIVE continental margins where the dense ocean crust is forced under the continental crust.At CONVERGENT boundaries
31The U.S. Pacific coast is an ACTIVE continental margin that has steep rocky mountains with little beaches.
32The Andes Mountains in South America are the worlds longest mountain range. It is an active continental margin. The Peru-Chili TRENCH runs along the western edge of the continent
33Active continental margins have steep slopes and deep trenches What feature is missing????Coastal mountainsSteep continental slopeDeep trenchAbyssal plain
34Deep trenches are located around the Pacific ocean – Color those Dark Blue
35The Mariana Trench It's the deepest spot in the world! "Grand Canyon of the Pacific”It’s 1,580 miles long and 43 miles wide.It is 11,033 meters, 36,201 feet or 6.86 miles deep (below sea level)The pressure at the deepest part of the Mariana Trench is over 8 tons per square inch.(compared to 14 pounds/sq. in. on the surface) .If Mount Everest, the highest mountain on Earth, were placed in the trench it would be covered by over one mile of water!
36How deep is it? Mariana Trench Is the deepest Place on the Earth! 29,000 ftMariana TrenchIs the deepestPlace on theEarth!Mt. Everest could fit in the Mariana Trench and still not stick out above the water!https://www.youtube.com/watch?v=v5DG5Eup9ss36,200 ft (6.8 miles!)
37Match that ocean feature! Under sea volcanoes.Flattest part of the ocean.Deepest places in the ocean.Shallow water at edge of a continent.Margin where earthquakes and volcanoes occur.Where the magma pushes up.43,000 miles long!Where the continent ends.57631248Active marginPassive marginRidgeRift valleyTrenchSeamountAbyssal plainContinental riseContinental shelfContinental slope
38The west coast of the U.S. has steep, sloping canyons
45Bell work 1. Where is new ocean floor being created? 2. Where is ocean floor being destroyed (recycled)?3. Where is new land being added to continents?d. ridgesb. trenchesc. Continental slopea. Abyssal plainb. Trenchesc. Continental sloped. Mid-ocean ridges
46Video Quiz on ocean features Finding Nemo video clips are located on the faculty Oswego (O:) Drive
47Bell work What percent of salt does the ocean contain? What body of water is the saltiest?What percent? ___________%