He suggested that at the centre of oceans, molten material would rise from the Earth’s mantle, causing new sea floor to be created, pushing the ocean floor. He also suggested that there were ocean trenches where old sea floor would then go back into the mantle, and molten. He found that these ocean trenches, the deepest parts of the ocean, were very near continental plates. Hess theorized that the action of the sea floor spreading caused continents to move apart and so this being evidence for continental drift, showing why it happened. The evidence of sea floor spreading was further supported by Vine and Drummond, who studied the magnetic pattern of the sea floor.
This movement changed the layer composition and even the direction of the layers that form Ayers Rock. ("Geology," 2008) Information about this movement is more difficult to locate than the Petermann Orogeny, but the impact is clear. The Alice Springs Orogeny was an intraplate contraction which changed the face of central Australia. It occurred approximately 300 million years ago. ("Geology," 2008) It resulted in the folding of the area and shortened the north/south length of the area by about 8.7 miles.
These long term variations in sea level can be caused by major glacial episodes, changes in the hydrological cycle, vertical land motion or even changes in the ocean and coastal circulation. These reasons can be put into two categories which are known as eustatic and isostatic change. Over the years the global sea level has overall significantly increased from 16BC which was when it was the world’s lowest sea level, however, it has fluctuated throughout the past thousand years. Eustatic change is when there is a rise or fall in sea level changes relative to the land, due to an alteration in the volume of water in the oceans or, alternatively, a change in the shape of a drainage basin and hence a change in the amount of water the sea can hold. Throughout and after an ice age, eustatic change takes place.
a. strain buildup only b. location of foci c. magnitude of P-waves [pic] d. reoccurrence rates of earthquakes in an area and the rate of strain buildup 2. What are most earthquakes associated with? a. rift valleys b. mid-ocean ridges c. divergent plate boundaries [pic] d. plate boundaries 3. At what point in the graph would a rock be permanently deformed? [pic] a. at the start of the stress [pic] b. past
Wegeners ideas were proved even further, increasing our knowledge of tectonic events. Sea floor spreading shows that rock is being both created and destroyed. In the 1950s and 1960s, ages of the ocean floor were measured. The surveys suggested that very young rocks, ageing less than 1 million years old, are found near ridges and older rocks, ageing over 200 million years, are found near the continents. Evidence of sea floor spreading can be found in the Atlantic, where it is believed that the North American and Eurasian plates are moving apart at a constructive plate margin.
b) Faults develop and the outer blocks move upwards. Reverse faults are formed. c) Central block stays in place and a rift valley is formed. RIFT VALLEY LAKES These have been formed on the floor of the rift valley and they vary in size, depth and salinity. Examples of the salty lakes are Lake Natron, and Lake Magadi.
Bacton’s geology is comprised of clay, silts and sand. It has a wide sandy beach. It is at risk from coastal erosion such as longshore drift and if it was not protected, the gas terminal would cease to function which would make a lot of the population in Bacton redundant. Also, it poses an environmental hazard if an explosion occurred and gas escaped. Happisburgh is composed of several glacial tills
They may be initiated when a drill hole penetrates a confined, high-pressure aquifer. Despite efforts to contain the resulting flows, such drill holes sometimes flow out of control or they may even "blow" out with considerable force (similar blowouts can happen when oil or gas wells are drilled, and zones of high-pressure fluids - liquids or gases - are encountered). The flows may continue for several months, or even years, resulting in considerable amounts of water and washed material being carried upward to the surface of the ground. References Bluemle, J. P., and Clayton, L., 1984, Large-scale glacial thrusting and related processes in North Dakota: Boreas 13, 279 - 299 p. Bluemle, J. P., 1993, Hydrodynamic blowouts in North Dakota: in Aber, J. S. (ed), Glaciotectonic and Mapping Glacial Deposits: Proceedings of the INQUA Commission on Formation and
Foredune and Second dune For the natural processes, Foredune and Second dune both are influenced by the seasonal wind, waves and parent rocks form Port Phillip Bay. During the flooding period from Port Phillip Bay and hardened into sedimentary rocks consequently, Foredune was formed as sediments washed from land by waves where eroded to form the underlying bedrock of the area (Gregory 1912) In terms of temporal scale, the pattern and shape of Seaford Beach influenced by seasonal alternations in dominant waves, which affected by two different directional wave during summer and winter months (Bird, 2011) There are gently curved beaches on coasts of Port Phillip Bay shaped by locally generated waves instead of received ocean swell (Figure 4) Although the beach materials, like sand and seashell, are removed seaward by storm waves, the coast outlines would maintain the smoothly curved shapes when the shape is established (Bird,
Both natural and human factors contributed to transforming the hazard into a disaster. Looking at the natural factors of the disaster, the source of the tsunami wave can be attributed to two tectonic plates: The North-South running Indo-Australian tectonic plate and the Eurasian tectonic plate. (Forrest 2005, p. 12) When the two plates shifted “about twenty miles below the surface of the sea,”(Forrest 2005, p. 12) they set off a “one-thousand mile long rupture” which subsequently released the energy equivalent of a 250-megaton bomb.’ (Forrest 2005, p. 12) However the magnitude of the destruction cannot solely be blamed on the tsunami wave. The natural propensity of human’s to build and inhabit low-lying areas near coastlines also contributed to the scale of the disaster. With such a large number