Geological Research of Mine Hill Preserves - Term Paper Example

 Mine Hill Preserves Abstract The paper examines the geological nature of Mine Hill Preserves, Connecticut. The complex features present in Mine Hills are explained in detail. Additionally, the findings about the aspects of glaciations history of Mine Hill are detailed in the paper. TABLE OF CONTENTS Introduction………………………………………...4 Formation of Mine Hill…………………………….4 Location of Mine Hill……………………………....5 Mine Hill Findings………………………………....5 Glaciations History…………………………………6 Mine Hill Glaciations………………………………6 Conclusion…………………………………………..7 References…………………………………………..8 Introduction In modern geological research, Mine Hill is one of the most exciting regions. The hills are comprised of hard crystalline rocks as well as a few softer rocks. The Mine Hill is situated near the valleys of Western Connecticut and the formation of Mine Hill is one of the most puzzling riddles for geologists in the modern era. Geologists have now begun to understand the actual reasons for the formation of Mine Hill. The events which had helped in the formation of the hills millions of years ago are being unfolded presently. It is now agreed by modern geologists that the theory of plate tectonics can correctly explain the formation of Mine Hill. This theory was formerly called continental drift, but the current theory of plate tectonics is an advanced version and a much improved version of continental drift. Formation of Mine Hill There are two natural forces in action. They are plate tectonics and the water action which combined together help in creating the three primary kinds of rocks found in nature: the sedimentary rocks, igneous rocks and the metamorphic rocks. Tim Clifford (2009 p. 34) state ‘The rock cycle takes place over a very long period of time. It may take millions of years for a rock to change from one type to another. Understanding the rock cycle can help us understand how the Earth was formed and continues to change.’ It was about 200 million years ago that Avalonia and North America experienced the second period of geological change. With this geological change, there was a major rifting which in turn created a new ocean between the landmasses of Avalonia and North America. However, the rifting did not eventually create the ocean and a sediment filled valley in Connecticut was left behind as a result. The third phase of rifting was initiated about 180 million years ago and during this period, another new ocean tried to form. This time the ocean tried to form between the landmasses of Avalonia and Africa. The ocean did not form unfortunately, however the North American continent was welded together with Avalonia. This attempt of rifting was a successful attempt and helped create the Atlantic Ocean. The Atlantic Ocean continues to widen even today and expands the rate of 2 cm each year. In present day, the segments of Rhode Island, the eastern part of Connecticut as well as the southeastern part of Massachusetts are actually the part of the landmass Avalonia. The eugeosyncline rocks and the miogeosyncline rocks which lie between Housatonic Islands and Avalonia are the only remnants of the Iapetos Ocean. The Cameron’s Line is one of the most important features in the geology of Connecticut; however Cameron’s Line has been heavily folded in present time. The junction between the eugeosyncline and the miogeosyncline rocks in Mine Hill is indicated by the Cameron’s Line. Location of Mine Hill The location of the Mine Hill is to the east of the Cameron’s Line, and is characterized by metamorphosed eugeosynclinal deepwater sediments belonging to the Iapetos Ocean. There is also another important feature in the Mine Hill, Mine Hill Granite Gneiss. The Mine Hill Granite Gneiss is almost a 400 million old rock structure which is comprised of quartz, feldspar and mica. Since there is presence of minerals such as mica, the rock is referred to as granite gneiss instead of being referred to as the granite. Although it is certain that the origin of the rock is igneous in nature, there is a certain gneissic characteristic of the rock which signifies that the rocks were in tremendous pressure, which compelled the minerals to develop in a parallel way. Therefore, the Mine Hill Granite Gneiss is a combination of igneous and metamorphic rocks. The Hartland Formation is basically the type of metamorphosed sediments which belong to eugeosyncline. They also show a wide array of appearances and compositions. They comprise of quartzite which is visually similar to Mine Hill Granite Gneiss and metamorphosed black shale which is extremely brittle. Mine Hill Findings Along the southwest direction of the Mine Hill are found the famous quartz-siderite veins. These veins contain various types of minerals and also contain certain wonderful specimens collected from the gneiss. In the last two centuries, more than seven different quartz siderite veins have been discovered in Mine Hill. On a couple of these veins, some tunnels have also been cut. Among them, the largest tunneling was rendered in the biggest vein. Several vertical shafts and horizontal tunnels were integrated in that tunnel. There are two major tunnels; the North Adit and the South Adit which were dug in the north and south of the Mine Hill Preserve respectively. Additionally, a number of trenches and shallow test pits were dug in order to find out if siderite or quartz is present in Mine Hill. The lower and upper quarries still have signs of several outcrops of the veins. Glaciations History The climate of our planet is affected by the position, size and shape of the continents as well as the position and height of mountain ranges. Tim Clifford (2009 p. 24) quotes ‘Usually, mountains form in ranges, or groups. Some of the best-known mountain ranges are the Himalayas, the Alps, and the Andes. The Rocky Mountains stretch all the way from New Mexico to British Columbia, Canada. That’s about 3,000 miles (4,828 km).’ Therefore with the growth of North America in size, the mountain ranges along the edges started moving towards the north and in the last 500 years, the mountain ranges started to turn counterclockwise. This also changed the climate pattern. In the past, there was a tropical climate which was very steady whereas now, the climate is temperate and the climate experiences warm and cold phases alternatively, in 100,000 year climate cycle. During the warm periods such as the one in the present, the ice sheet melts whereas in the cold periods, the huge ice sheets advances. The glacial periodicity advances was first proposed in the 19th century by James Croll and subsequently by Milutin Milankovitch in the 20th century. Their theory is now being generally accepted by geologists around the world. Recent studies have conclusively found evidence that glacial cycles are indeed true and in North America, glaciations process commenced 5 million years ago. Mine Hill Glaciations About fifteen thousand years ago, the last ice sheet from New England retreated. There is evidence that the Wisconsin Ice Sheets were the last major glacial advance. The ice sheet changed the landscape of New England. When the Wisconsin Ice Sheet melted, a terminal moraine or low sand ridge was formed which is now known as Long Island. When the ice melted, several tons of crushed rock and sand inside the ice was dumped on the New England area. There is a thick drift present in the Mine Hill preserve and this drift is prominent three particular places: along Mine Hill Road, on top of the hills as well as in an area towards the lower quarry’s south. The drift which is present at the hill’s top is called drumlin and was probably formed during the advance of the Wisconsin Ice Sheet. Towards the lower quarry’s south, there is a stratified drift present. Conclusion Tim Clifford (2009 p. 33) state ‘Once rocks begin to break down through weathering, erosion can take over. Erosion is the process by which rock particles are moved. Water, wind, ice, and gravity can all cause sediment to break away from rocks.’ Presently, the geological changes in Mine Hill are insignificant. The earthquake activity as well as the erosion processes has slowed down greatly. The rest of the Mine Hill Preserves is replete with shallow till patches which are discontinuous nature as well as the frost crack blocks containing Hartland Metamorphics and Mine Hill Granite Gneiss. Chunks of rocks are still scattered in Mine Hill, probably fragmented from the bedrock during the glacial retreat when there was a permafrost condition in the southern part of New England. These rocks have a characteristic round shape which differentiates them from the fresh rubble which was left from recent quarrying and mining on Mine Hill. The next major geological event would probably be after 25,000 years, which would be the return of the ice sheet in Mine Hill. References Beck, Warren A, and Ynez D. Haase (1974) Historical Atlas of California, Norman, Oklahoma: University of Oklahoma Press Clifford, Tim (2009). Geology, Florida: Rourke Pub Group Dillon, Brian D (1994). Alameda District Plan, Los Angeles, California: Prehistoric and Early Historic Archaeological Research. Environmental Impact Report. Pacific Palisades, California: Greenwood and Associates. Kulik, Stephen (1984). The Audubon Society Field Guide to the Natural Places of the Northeast: Inland, National Audubon Society MacGregor, K.R., Anderson, R.S., Anderson, S.P., and Waddington, E.D.(2000) Numerical Simulations of Glacial-Valley Longitudinal Profile Evolution: Geology, v. 28, p. 1031–1034. Warburton, J., and Beecroft, I., (1993) Use of Meltwater Stream Material Loads in the Estimation of Glacial Erosion Rates: Zeitschrift für Geomorphologie,v. 37, p. 19–28. Read More