Download Geological Processes & Environmental Degradation: Rock Cycle, Dust Storms & Desertificatio and more Study notes Biology in PDF only on Docsity! Name__________________________________________________________________________________________ Assignment # 6 - Soil and Desertification due Feb. 1. Reading: Chapter 3 World on the Edge. Supplemental reading: Dust Bowl. For those who have had trouble downloading the eBook, I’ve uploaded Chapter 3. However, I still recommend you download the book, primarily because the references for all chapters are at the back and there is additional information on original sources so you can better evaluate Brown’s conclusions. Answer the questions using word processing and submit in the dropbox for assignment 6. Remember to save the document with a file name that includes your name and the assignment number. 1. Using the internet and/or other sources for information, explain the "rock cycle". What is it and how does it work. Important terms and concepts are: major rock classifications: igneous rocks, metamorphic rocks, and sedimentary rocks. What they are and how they are formed (the processes). What roles do weathering and plate tectonics play in the rock cycle. The rock cycle is the processes by which rocks are formed, broken down, and reformed on Earth. Because it is a cycle we can begin anywhere. I’ll start with the formation of igneous rocks, since this is the source of all of the initial rocks on Earth. Igneous rocks, which include granite, basalt, and pumice, are formed from cooling magma from volcanoes and lava flows. These rocks can be broken down by erosion and weathering into smaller rocks, gravel, sand, and silt, which can be deposited in sediments and compressed into sedimentary rocks (including: sandstone, limestone, and shale). Alternatively, igneous rocks can be pushed back into the mantle, by processes such as subduction at tectonic plate boundaries and re-melted. Sedimentary rocks and igneous rocks can also be transformed by heat and pressure to form metamorphic rocks (including; marble and slate). Metamorphic rocks can then either be broken back down to form sediments and sedimentary rocks or melted back to magma in the mantle to start again. Tectonic plate movement comes into play with the formation of igneous rocks as lava is released at spreading plate boundaries and hot spots or by volcanoes as plates are subducted, and as plates are pushed into each other and by the transformations into metamorphic rocks as the processes result in pressures on existing rocks. 2. What causes dust storms and dust bowls? Dust storms and dust bowls are caused by multiple factors. A primary factor is loss of vegetation that would normally hold soil in place and slow the wind (particularly trees). The other major contributing factor is drought. 3. What is desertification? And what are its causes? Desertification is the persistent degradation of land once the vegetation is gone. It can be brought about by numerous causes; changes in rainfall patterns (one of the
