How Old Is The Oldest Oceanic Crust

1960- Harry H. Hess came up with idea that the oceanic crust is arranged between the mid ridge and it spread throughout the other ridges.

20. On the left side of the graph (Tonga Trench) label the Pacific Plate (right side of the line of best fit) and the Indian Australian Plate (left side of the line of best fit)

The first, would be Land features. Alfred Wegener saw how the coal fields in North America and Europe lined up, he also realized that mountain ranges in North America and Africa lined up. The second, evidence he used were the fossils. There were three types of fossils he found the first was the glossopteris a fern like plant found in Africa, South America, Australia, India, and Antarctica. The second and third were the Mesosaurus and the Lystrosaurus fossils, they were freshwater reptile fossils on continents separated by oceans. The third evidence Alfred Wegener used was, the climate zones. Alfred Wegener looked at the past of the climates and he found scratches in rocks from glaciers in South Africa. Those were the three main evidences Alfred Wegener used to prove Continental Drift

Studies of the age of molten rock in the ocean crust confirm the magnetic data. Molten rock contains radioactive isotopes used to calculate the time of the eruption. Rocks near the Mid- Atlantic Ridge, in addition to current like structures happened to be rather young, only some million years aged or a lesser amount (Trefil & Hazen, 2010). Rocks gathered one after another farthest from the range established them to be in turn older. Up to date evidence on charting the surfaces of oceans, maps of rock magnetism, and data on the age of rock indicate to countless expert that the span of the Atlantic Ocean for all intents and purposes is

Determine the relative age each of the geologic structures shown in the geologic cross section below (Figure 9.17) from youngest to oldest; then answer the questions below. As before, a wiggly line running across the geologic cross section indicates an unconformity and a fault is indicated with a bold straight line.

The Mesozoic tectonic history of the North American Cordilleran region is very complex and involves:

It has been known for well over a century now that the Earth’s core, mantle and the crust make up the basic structure of the Earth. However, there is some controversy over how and when the Earth produced its core, mantle and crust. In this essay, I will first discuss about the formation of the Early Earth and its Moon, then about the methods used to pinpoint the age of the Earth. Other than that, I will also expand on core and mantle formation, as well as the eventual production of the continental crust.

John et al. 2012). These clasts, embedded in the fine-grained pelagic sediment at site 913, are confirmed to be glacial deposits due to the evidence of glacial abrasion on the surfaces of the clasts (Eldrett et al. 2007). Additionally, the lack of sedimentary structures that would suggest gravity flow-initiated deposition of these glacially deposited clasts, results in a dropstone classification. A summary of the lithological units of site 913 can be seen in table 2. Note. From ‘Proceedings of the Ocean Drilling Program, Initial Reports’ (Myhre et al.

Ridge – ridges are formed thru tectonic activity where magma rises up through the gaps between the tectonic plates. As the magma keeps flowing, the layers keep bulding up, forming the mountainous oceanic ridges. the oceanic ridge system is a continuous mountain chain extending into/throu all the major oceans.

The Pacific Plate is the largest oceanic tectonic plate on the Earth that lies under the pacific ocean which covers about 102 million square kilometres. The plate is currently reducing and the Atlantic Ocean increases in size pushing the North American Plate gradually westward. This event has formed subduction zones in the oceanic crust that make the huge subduction zone, earthquakes, volcanoes to explode, and

Passive continental margins are inactive regions. They are at a distance from plate boundaries. When continental blocks rift apart and are separated by seafloor spreading passive continental margins develop. For the most part passive margins are relatively wide and are known as sites where abundant amounts of sediments are deposited. Some of the main features of passive continental margins would be the continental shelf, the continental slope, and the continental rise. The continental shelf is a gently sloping , submerged surface extending form the shoreline to the deep-ocean basin. It consist of continental crust capped with sedimentary rocks and sediments eroded from adjacent landmasses. The seaward edge of the continental shelf is the continental slope. The continental slope is a steep structure that marks the boundary between continental crust and oceanic crust. The inclination of the continental slope varies from location but has an average of about five degrees in places exceeds twenty-five degrees. The continental slope merges into a gradual incline known as the continental rise . The continental rise can extend seaward for hundreds of kilometers. The continental rise is made up of a thick accumulation of sediment that has moved down the continental slope and onto deep-ocean floor. Majority of the sediments are delivered to the seafloor by turbidity currents that periodically flow down submarine canyons. Submarine canyons are know for their Deep, steep-sided

After World War 2, the U.S. Office of Naval Research intensified efforts in ocean-floor mapping, leading to the discovery of the Mid-Atlantic Ridge to be part of a continous system of mid-oceanic ridges on all ocean floors, prompting Harry H. Hess to suggest the theory of sea-floor spreading. The oldest fossils found in ocean sediments were only 180 million years old and little sediment were accumulated on the ocean floor. Thus, he suggested that seafloors were no more than a few hundred million years old, significantly younger than continental land due to

The continental crust consists of igneous and sedimentary rocks. The oceanic crust consists of the same with a substantial layer of sediments above the rock. The crust covers the outer ridged layer of the earth called the lithosphere. The lithosphere is divided into seven main continental plates. These continental plates are constantly moving on a viscous base.

On the ocean floor the plates are spreading. All along the mid ocean ridge, volcanic activity is pouring new lava out onto the seabed. As it hardens, it becomes new rock, gradually pushing the crust, on either side of it away. Another type of spreading boundary is the African Rift Valley. As the two

This piece of work will discuss topics such as early earth systems, evolution of the earth’s mantle and how the continental crust was formed.