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.
The uplift was surrounded by an epicontinental sea where sediment accumulated in marine margins creating sandstones, siltstones and limestones throughout the Basin. Facies 1 in the carbonate unit consists of 4-34 cm beds of black micrite, matrix supported with less than 5-10% grains making it a mudstone; crystalized shell fragments are present, 2-4 mm bivalve bioclasts and sparse 3-5 cm rugose coral and crinoid fragments; horizontal inclined burrows are
The evidence of sea floor spreading was further supported by Vine and Drummond, who studied the magnetic pattern of the sea floor. They found that the Earth’s magnetic field changes over time, because as magma from the mantle rises to the crust it cools but the basalt will align to the field it cools to. It is also found that on either side of mid oceanic ridges there were symmetrical magnetic patterns, so suggesting that the ocean was created at the mid oceanic ridges and as new ocean floor cooled, it pushed the crust away. Both Hess and Vine and Drummond found evidence that is crucial to the explanation of how continental drift happened, and it is very important in the development of geologists understanding, however other people found evidence to support continental drift also. Dan McKenzie went on to further explain sea floor spreading, being able to explain why new crust was made at mid oceanic ridges.
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,
Describe sea floor spreading and explain why it is an important piece of evidence for advancing plate tectonics. -It is a theory where land is created at the ridges and is then split apart. 7. Describe the general relationships that exist among the following: distance from spreading centers, heat flow, age of ocean crustal rock, and ocean depth. The farther away the older, the closer to the spreading center the warmer and more active.
However, kames consist of gravel and sand deposited by streams that flowed into holes in the glacial ice, depositing sediment in the holes. When the ice later melted, the materials slumped down, often forming conical-shaped hills. Thus, kames are formed "from above," veblens "from below" (diagram "A" showing difference in the origin of these two kinds of features ).
The cross section helped to better understand the thickness, flow direction and distribution of the aquifer(s) within the mapping area. 3 river stream gages are placed in the stream in order to better understand the relationship between groundwater and surface water by giving quantities of discharge/recharge in cubic feet per second (cfs). Understanding the relationship between the groundwater and surface water gives aid for producing the potentiometric surface map which includes the gaining (effluent) and losing (influent) parts of the stream. Results Two aquifers were located, a confined and unconfined aquifer. The unconfined aquifer, or the upper aquifer, (see cross and contour map) consists of a predominately sand rich and partial gravel unit and is approximately 50 feet thick.
3. Sandy soil is used to make pots, toys and statues. 4. Soil is affected by climatic factors. 5.
1/3 of population live in SE – but driest part of the UK (600-800mm p.a.) – in mountainous areas like N Wales – low population but high rainfall totals (200mm p.a) www.geobytesgcse.wordpress.com St Ivo School Geography Department - GCSE REVISION Point source pollution – contamination resulting from emissions from a particular location. Define point source pollution and give an example of this in an LIC. www.geobytesgcse.wordpress.com Fold along
Saltmarshes consist of two main geomorphological elements. First, a convex upward, planar or concave upward vegetated platform high in the tidal frame that is flooded by the tide and, second, generally unconnected networks of tidal creeks that branch and diminish landward towards the interior of the saltmarsh from its seaward edge. Additionally, some saltmarshes have pronounced areas of higher ground (levees) along the banks of the creeks, varying densities of water-filled depressions (salt pans) or bare areas of mud (mud basins) which are connected to the creek system and which drain at low tide. Seven main types of saltmarsh are recognised (Figure 2.1): • Open-coast marshes - typically sandy systems with relatively exposed sandflats to seaward; • Open-coast back-barrier marshes - sandy-muddy systems found on the sheltered, landward side of coastal barriers; • Open-embayment marshes - marshes which fringe the edges of large tidal embayments with unobstructed entrances and tend to be sandy; • Restricted-entrance embayment marshes - typically mixed sandy-muddy systems, with the embayment partially closed off at the mouth by one or more spits or promontories; • Estuary-fringing marshes - most commonly muddy and found in estuaries with little obstruction at the mouth; • Estuary back-barrier marshes - found in estuaries behind barriers or spits at the mouth, often composed of mud overlying sand; and 10 • Ria/Loch head marshes - marshes restricted to the drowned river valleys of the south west, where pioneer to upper marsh occurs with transitions to woodland Saltmarshes are, in effect, vegetated mudflats; although the morphology and the processes which act upon them are distinct in several respects. Saltmarsh surfaces are higher than Science Report - R&D Technical Report (PFA-076/TR) 13mudflat surfaces and so they are flooded less