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Washington land features
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- 2. Land Features • PhysicalAttributes – Makes up a Geographical Unit • Topography – Shaped By: • Uplift, Deformation, and Breakdown of Bedrock • Erosion, Transport, and Deposition of Sediment • Terrain – Created by Plate Tectonics
- 3. Theory of PlateTectonics • Plate Tectonics – Creates and Shapes the Earth’s Crust • 7 Large • 18 Small – Granite – Basalt • Movement with the Lithosphere – Explained by the Theory of Plate Tectonics • Mountains and Volcanoes • Earthquakes and other Geophysical Occurrences
- 4. Western US WashingtonState • Home to 5 major Volcanoes • Cascade Range – Volcanic Arc • Stretches from Southern British Columbia all the way to Northern California • Past 12,000 years over 200 eruptions • All Washington Volcanoes erupted except Mount Adams. • All still active today
- 5. Main Movement • ConvergentContinental margin- collision boundary between two plates • Cascadia Subduction Zone – Northern American plate and Juan de Fuca Plate • Both plates converge at a rate of about 2 inches per year
- 6. Geological Events • ActiveVolcanoes – The Ring of Fire • Mount St. Helens – March 20, 1980 • 4.1 Earthquake – May 18, 1980 • 5.1 Earthquake
- 7. Rock Types • NorthwestAmerican Plate – Northwest Region • Igneous Rocks • Igneous Rocks – Volcanic • Aboveground – Plutonic • Belowground
- 8. Geological Relationships • Basalts – Series of Lava Flows • Roxa Flow • 1 Million to 12 Million Years Ago • Hot Rock – In the Mantle Rise • Plumes • Plumes – Volcanic Rock is Created
- 9. Geological Importance • Createdby Volcanic Eruptions – Formed Large Granite Rocks • Cascade Mountain Range – Formed by Floods of Molten Rock – Erupted through Cracks in the Crust • Formed Basalts of the Columbia Plateau • Continental Glaciers – Rose and Scoured • Constructing the Washington Landscape
- 10. Conclusion • History RevolvesAround Natural Disasters – Events Constructed the Land • Cascade Mountain Range – Mt. Saint Helens – Events Created Usable Materials • Rich Mineral Soil – Logging • Mining – Gold and Silver
- 11. References CHESTER, R. (2008).Chapter 11: PLATE TECTONICS: THE EARTH SCIENCE "THEORY OF EVERYTHING.". In , Furnace of Creation Cradle of Destruction: A Journey to the Birthplace of Earthquakes, Volcanoes, & Tsunamis (pp. 130-142). American Management Association International. Retrieved from EBSCOhost. Dance of the Giant Continents. (2011). Retrieved July 10, 2011, from University Of Washington: http://www.burkemuseum.org/static/geo_history_wa/Dance%20of%20the%20Giant%20Continents.htm Dietrich, W. E., & Perron, J. (2006). The search for a topographic signature of life. Nature, 439(7075), 411. Retrieved from EBSCOhost. Earthquakes in Washington. (2011). Retrieved July 10, 2011, from Washington State Department of Natural Resources: http://www.dnr.wa.gov/researchscience/topics/geologichazardsmapping/pages/earthquakes.aspx Lange, G. (2002, April 13). Earthquake Hits Puget Sound Area. Retrieved July 10, 2011, from History Link.org: http://www.historylink.org/index.cfm?DisplayPage=output.cfm&File_Id=2063 Lerner, K. L. (n.d.). Bowen’s Reaction series. Retrieved from http://science.jrank.org/pages/1003/Bowen-s-Recation-Series.html Merali, Z., & Skinner, B. J. (2009). Visualizing Earth science. Hoboken, NJ: Wiley. Nelson, P.A. (2010, Sept). Volcanic Landforms, Volcanoes and plate tectonics. Retrieved from http://www.tulane.edu/~sanelson/geo1204/volclandforms.html Rosenberg, J. (n.d.). Mt. St. Helens. Retrieved July 10, 2011, from About.com: http://history1900s.about.com/od/horribledisasters/p/mtsthelens.htm Schettino, A., & Scotese, C. R. (2005). Apparent polar wander paths for the major continents (200 Ma to the present day): a palaeomagnetic reference frame for global plate tectonic reconstructions. Geophysical Journal International, 163(2), 727-759. doi:10.1111/j.1365-246X.2005.02638.x "Washington." The Great American History Fact-Finder. Boston: Houghton Mifflin, 2004. Credo Reference. 30 May 2007. Web. 11 July 2011. <http://www.credoreference.com.ezproxy.apollolibrary.com/entry/hmgahff/washington>. What is a Geological Event. (2011). Retrieved July 10, 2011, from Answers.com: http://wiki.answers.com/Q/What_is_a_geologic_event
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Editor's Notes
- #2 Good Evening, We are Learning Team A and will be making a presentation tonight on Washington Land Features. Our team is comprised of Anita Beckman, Matt Burbidge, Shannon Hendrick, Heather Mears, and Nora Packineau.
- #3 Land features are physical attributes that make up a geographical unit. Landforms are defined by its outward appearance and position within a landscape or seascape. Topography is shaped by the &quot;uplift, deformation, and breakdown of bedrock and the erosion, transport and deposition of sediment&quot; (Dietrich & Perron, 2006, p. 1). Terrain in the state of Washington is created by plate tectonics and other geological events. Geological relationships identify the importance of how landform elements create physical characteristics and how those attributes interface with one another.
- #4 The creation and shape of the earth's crust is a credit to plate tectonics (Chester, 2008). Movement within the Earth’s lithosphere is explained by the location of plates in geologic past and present. The theory persists that the movement of plates is the attributing factor to formations such as mountains and volcanoes (Merali & Skinner, 2009). Earthquakes and other geophysical occurrences are also created by tectonic movement. Plates shift and merge in a variety of ways; there are seven sizeable and 18 smaller plates that associate with one another. The theory imparts that there was a root continent that has since broken apart. Separation of this supercontinent is the cause of apparent polar wander (APW). What we see today is a changing orientation of continents, known as continental drift (Schettino & Scotese, 2005). Continental plates are largely made up of granite, whereas oceanic plates are basalt. The lighter continental plates are more buoyant than the heavier oceanic plates. Lighter plates will typically glide elevated on the earth's mantle. Changing patterns of plate motion causes them to converge and slip beneath one another (Merali & Skinner, 2009). This constant motion is the cause of geological events.
- #5 Western US Washington State Washington is home to five major volcanoes including Mount Baker, Mount Rainier, Glacier Peak, Mount Adams, and of course Mount St. Helens. All these volcanoes are part of whats known as the Cascade Range which is basically a volcanic arc that stretches from Southern British Columbia all the way to Northern California. Even though there are literally thousands of small volcanos within the Cascade Range, the major composite volcanic centers in the U.S. range possess the most hazards, concerns, and studies. Over the past 12,000 years, these Washington volcanoes have erupted over 200 times shooting tephra (ejected material), lava flows, lahars, and even debris avalanches (Mifflin, 2004). Nearly all Washington volcanoes except for Mount Adams have erupted since the creation of the United States back in 1776. All of them still have active seismicity and/or geothermal activity as well (Mifflin, 2004)
- #6 Washington is situated at a convergent continental margin, the collisional boundary between two tectonic plates. The Cascadia subduction zone, which is the convergent boundary between the North America plate and the Juan de Fuca plate, lies offshore from northernmost California to southernmost British Columbia. The two plates are converging at a rate of about 2 inches per year as well as the northward-moving Pacific plate is pushing the Juan de Fuca plate north, causing complex seismic strain to accumulate. Earthquakes are caused by the abrupt release of this slowly accumulated strain (Mifflin, 2004).
- #7 Volcanic eruptions, earthquakes, and any event that causes ecological damage, are geological events (What is a Geological Event, 2011) . Geological events can be given a precise date or they can be related to events that happened before or after them. Washington is on a collisional boundary of two tectonic plates. The plates’ converging causes a complex strain. Earthquakes happen here when the strain is abruptly released (Earthquakes in Washington, 2011). It is believed that Washington borders one of the most active volcanic areas on earth, The Ring Of Fire. In the late morning hours of April 18, 1949, Western Washington was hit with a 7.1 magnitude earthquake. The earthquake lasted for 30 seconds, and a tremor was felt over a 230,000 square mile area (Lange, 2002). May 18, 1980 is labeled the worst volcanic disaster in United States history; it was the day Mount St Helens erupted. An earthquake with a 4.1 magnitude rumbled under Mount St. Helens on March 20, 1980. Seven days later, a small explosion blew a 250-foot hole in the mountain and released a plume of ash. Many similar miniature explosions occurred over the next month. The morning of May 18th arrives and Mount St. Helens is rocked by a 5.1 magnitude earthquake. It took 10 seconds for the bulge to give way in a giant rock avalanche. This avalanche created a gap in the mountain laterally ruptured a huge blast of pumice and ash. The avalanche traveled 70-150 miles per hour. The pumice and ash traveled at 300 miles per hour with raging heat of 660 degrees Fahrenheit. Nothing within a 200 - mile radius survived. The eruption lasted for nine hours (Rosenberg). Washington is home to several active volcanoes, which leaves the state vulnerable to another geological event.
- #8 Types of rocks found in the Northwest region and part of the North American Plate are igneous rocks. Igneous rocks are classified into volcanic and plutonic rocks (Merali & Skinner, 2009). Volcanic rocks are formed aboveground from lava and plutonic rocks are formed belowground from magma. Rocks known as aphanitic begin when lava cools rapidly. Mineral granite found in volcanic rocks is small, microscopic or not present. Plutonic rocks are easy to recognize, from the presence of mineral grains called phaneritic. One of the most common volcanic rocks is basalt. The rock is dark, contains low silica, and is a mafic. According to Bowens Reaction Series (Lerner, 2010), the program explains that minerals in igneous rock crystallize in an orderly sequence. The order of temperature changes causes the mineral to transform. Throughout the process plagioclase feldspar changes its composition from Calcium-rich at high temperatures to Sodium-rich at low temperatures. The transitional phase shows the compositional change and the order of nature. Understanding how feldspars are formed imparts a greater comprehension of how plagioclase occurs in most igneous rocks and how different rocks form from this process. Igneous rock is formed from the crystallization process from melt, also known as magma. Once the magma flows on the earth's surface it is extrusive volcanic rock. The rock becomes intrusive when magma solidifies at depth beneath the earth, and the rock is plutonic.
- #9 In Washington, on the northwestern part of Columbia River, the presence of basalts represents a series of lava flows that erupted about one million to 12 million years ago. The basalt flows, Roxa flow, erupted over a few weeks and traveled about 300km (Nelson, 2010). An interesting convection in the Earth's mantle indicates that the rocks do not travel in precise packaged convection cells. Hot rock deep in the mantel rise is long with thick blobs, called plumes. The plumes give rise to long standing sources of magma deep in the mantle. New volcanic rock is formed when the plume creates long lines and the volcanic form moves. Eventually the plume loses contact with the source of magma and volcanic rock is created. When Mt. St. Helens erupted in 1980, the eruption was preceded by numerous small earth tremors and steam venting. The eruption caused summit-blow-off removing upper 400m in one blast of rock and ash. According to the Bowens publication, by the end of the 19th century scientists recognized that all igneous rocks are from the crystallization of magma. Igneous rocks formed gave way to primordial starting material for different types of igneous rocks.
- #10 Volcanic eruptions, earthquakes, and any event that causes ecological damage, are geological events (What is a Geological Event, 2011) . Geological events can be given a precise date or they can be related to events that happened before or after them. Washington is on a collisional boundary of two tectonic plates. The plates converging cause a complex strain. Earthquakes happen here when the strain is abruptly released (Earthquakes in Washington, 2011).
- #11 Washington’s history revolves around natural disasters that have percolated the Earth’s surface for hundreds of millions of years. The series of happenings is what created the land features of impressive sustenance we see today. From the Cascade Mountain Range to the eruption of Mount Saint Helens, Washington is infamous for Mother Nature’s wrath. Fortunately, the United States Geological Survey (USGS) has researched, studied, educated, and created a way to predict such disasters to prepare its residence better and help victim’s distressed by geological events. Washington’s structure has concaved the state into a tourist attraction to gain more economic value. The state is more valuable today because of these natural disasters, from mineral rich soil for mining gold and silver to becoming a historic treasure.
- #13 Are there any Questions?