Geological Interest - Report Example

Running Header: Geological Interest Student’s Name: Instructor’s Name: Course Code & Name: Date of Submission: Contents Contents 2 2 1.0 Introduction 3 2.0Maslin Beach 3 2.1Rock Formation 3 2.2 Fault Block 6 2.3 The Sand in Maslin Beach 6 2.4 Type of rock in Maslin Beach 7 3.0 Morialta Gorge 8 3.1 Rock Formation in Morialta Gorge 8 3.2 Types of Rocks in Morialta Gorge 9 3.3 Direction of water flow 11 Conclusion 11 References 12 1.0 Introduction Geological factors play an important role in determining the characteristic of ground mass in relation to engineering process. According to Prince (2008, p. 8), all geological engineering factors are related to climatic conditions and focus in determining the depth of ground water and its presence. Additionally, geological engineering assist engineers to determine the need for sand replenishment in coastal areas as well as to establish the stability of sea cliffs, development of water front and construction of piers. Moreover, it aids in determining the behaviour of rocks and soils in order to solve many problems related to geological engineering. Therefore, geological engineering is essential in predicting how processes in the earth surface affect the activities undertaken by human beings. The aim of this report is to discuss the geological factors at Maslin Beach and Morialta gorge in Australia. 2.0Maslin Beach Maslin Beach is found in South Australia and it is located in the south coast of Adelaide. The Beach stretches for about 3 Kilometres and it is surrounded by high cliffs which provide suitable spots for viewing the beach. 2.1Rock Formation According to The Government of South Australia (2008, p. 2), the gently laying strata which can be found half way through the Maslin bay cliff are shortened by an overlying layer of cemented sandstone. The horizontal layer represents a breakdown in deposition which has occurred between the Tortachilla limestone, Maslin sand and Neogene sedments of the Hallet Sandstone which lie above the layer. Strzelecki (2011, p 24), states that when the ocean sea swept into the main land they formed estuaries where Maslin sand was deposited. The marine conditions that existed coupled with low salinity and oxygen led to the formation of Tortachilla limestone which is found below the horizontal layer in the cliff. Snippet(2005, p.40), notes that the limestone’s are green in colour due to the presence of glauconite grains which is a mineral that indicates low oxygen common in marine environments. Limestone below the horizontal layer of the cliff Source: Government of South Australia (2008, p.3) On the other hand, the Blanche point was formed by fossils of turreted snails which were abundant in some layers of the cliff after burrowing them (Government of South Australia 2008, p. 2). According to Snippet (2005, p. 41) the points in the Blanche are brackish and this signifies the exchange of gases between the snails and the atmosphere. The Blanche Point Source: Government of South Australia (2008, p.4) According to the Government of South Australia (2008, p. 3), the Neogene sediments of the Hallet Cove Sandstone were formed by fossiliferous slabs which fell onto the beach. The warm conditions which were followed by wetter conditions on the beach made the slabs to harden hence forming the Hallet Cove Sandstone. Snippet (2008, p. 43), notes that the varied hardness in relation to the sandstone occurred due warm conditions that were exposed to the fossils which were then followed by wetter conditions. 2.2 Fault Block At the base of the cliff in Maslin Beach there is a fault block which was formed as a result of deposits of young strata during the Oligocene and Eocene periods. The valleys that were left after the deposits were filled with mud and non-marine sands that were brought by the sea. According to the Government of South Australia (2008, p. 3), while the deposit were occurring the ice sheet that was on Antarctica grew extremely large leading to a decrease in the sea level. Snippet (2008, p. 43), notes that the Chinaman gully formation of the fault block represents the deposition on non-marine sands. This in turn led to the formation of the fault block. Fault block Source: Government of South Australia (2008, p.6) 2.3 The Sand in Maslin Beach Maslin beach sand is composed of white clay which occurred due to weathering of the siltstones at the Hallet cove. According to Snippet (2008, p. 47), Maslin beach has a variety of sands which include; concrete sand, white brick sand, plaster sand, paving sand and packing sand. Average % composition of sand in Maslin Beach Sediment type S Size range Average % Composition concrete sand ≥ 2000 0.20 white brick sand 1000 – 1999 0.35 plaster sand 500 – 999 2.74 paving sand 250 – 499 27.18 packing sand. 125 – 249 61.52 Silt/Clay 63 – 124 7.95 Source: Ramsdale (2010, p. 40) 2.4 Type of rock in Maslin Beach Strzelecki (2011, p. 24), notes that the cliffs in Maslin beach are formed by Ochre rocks and gull rock. Ochre rocks are coloured stocks which are composed of iron hydroxides and oxides. Their colours may vary from red, purple, yellow and orange. According to the government of South Australia (2008, p.1) the rocks are layers of sedimentary strata which have been formed due to geological processes. Ochre Rock Source: Strzelecki (2011, p. 24). 3.0 Morialta Gorge Morialta gorge is found in Adelaide hills. According to Bourman, Harvey and Bryars (2008, p. 77), the geology of the Morialta gorge affects the drainage network as well as the sources of building materials. The area was exposed to prolonged erosion and this led to the formation of the gorge. 3.1 Rock Formation in Morialta Gorge According to Margarey (2006, p. 4), the rocks in the Morialta Gorge began to form around 500 million years ago. This was during the Cambrian period when quartz particles were eroded and deposited over a flat region. Continued deposition of quartz in the area placed excessive pressure on the on the layers of quartz and this led to the occurrence of lithification. Bourman, Harvey and Bryars (2008, p. 75), note that Lithification is a process whereby loose sediments which are unconsolidated change into rocks through precipitation, compaction and cementation of individual grain sediments. This process occurred for many years leading to the formation of sedimentary rocks which are known as quartz sandstones. The rocks consist of rounded quartz grains which are characteristically 2mm in size. Gibson (2005, p. 24), states that during the Ordovician period the sandstone was folded and uplifted due to movements along the fault lines. The rock structures were exposed to comprehensive forces by the movements leading to the occurrence of metamorphism process. Metamorphism occurs due to extreme pressure and heat being applied on a rock over a long period of time and this leads to a change in the rock atomic structure without the rock melting (Margarey 2006, p. 4). Further movements in along faults caused the Morialta region to get uplifted. However, the uplift enabled the streams to increase their erosion activities and this led to the formation of the gorge. The streams were able to erode and wash away the soft quartz rocks thereby leaving the rocks that were more resistant. Rocks in Morialta Gorge Source: Bourman, Harvey and Bryars (2008, p. 75) 3.2 Types of Rocks in Morialta Gorge The rocks in Morialta gorge were formed as a result of faulting of ancient rocks (Bourman, Harvey and Bryars 2008, p. 75). These rocks include limestone and quartz rocks. Limestone rock is composed of 50 % dolomite and calcite, and less than 50% of other materials that compose a rock (Monroe, Wicander & Hazlett 2006, p.24). Limestone Source: Monroe, Wicander and Hazlett (2006, p.24). The quartz stones are made up of silicon-oxygen tetrahedral. According to Monroe, Wicander & Hazlett (2006, 32) quartz rock is found in igneous, metamorphic and sedimentary rocks. Igneous rocks contain the highest proportion of quartz, followed by metamorphic and sedimentary rocks Proportion of quartz in other rocks Quartz rock Source: Allen (2009, p.56) Source: (Monroe, Wicander & Hazlet 2006, p.32) 3.3 Direction of water flow According to Bourman, Harvey and Bryars (2008, p.66) the gorge collects most of the water and drains it in the lowest point of the cliff. Rainwater flows through the gorge and it is drained to the wetlands. Gibson (2005, p. 30) notes that small channel capacities decrease as they go downstream through the gorge. Therefore, the channel streams have constantly been inadequate in order to form a stream flow. The lack of inadequate water has led the streams to end up in wetlands and this means that the water does not reach the sea. However, due to the block placed on the streams by the sand dunes the streams have been forced to join Port River which flows to the north. Therefore, the water that comes through the gorges flows to the north through Port River. Conclusion In conclusion, the rocks that are found in Maslin beach are composed of Tortachilla limestone, Maslin sand and Neogene sediments of the Hallet Sandstone. This have in turn led to the formation of sandstone and Blanche point. Additionally, Maslin beach has a fault block which was formed as a result of young strata deposits. Furthermore, the beach has Ochre and gull rocks and at the same time it has a variety of different types of sand. On the other hand, the rocks in Morialta Gorge were formed when quartz particles were eroded and deposited over the region and then exposed to compression movements. The rocks in the gorge include limestone and quartz rock. In the Gorge, water flows in the northern direction through Port River. References Bourman, B, Harvey, N & Bryers, S 2008, Catchments and Waterways, Wakefield Press, South Australia. Gibson, C 2005, Geological Survey of Western Australia, Abe Books, Sydney. Government of South Australia 2008, ‘Maslin Bay’, In Geological Time, pp. 1-5. Magarey, D 2006,‘Getting to Know Moriatta’, In University of South Australia, pp. 1-33. Monroe, J, Wicander, R & Hazlett, R 2006, Physical Geology, Cengage Learning, Mason. Prince, D 2008, Engineering Geology, Springer, London. Ransdale, N 2010, ‘Assessing Sand Distribution in Beaches’, In Fielders University, pp. 1-60. Snippet, P 2005, Overseas Geology, Abe Books, Sydney. Strzeki, G 2011, Geology, Wakefield Press, South Australia. Read More