Rhyolite Rock Facts Geology and Uses

Rhyolite is a silica-rich igneous rock found throughout the world. The rock received its name from German geologist Ferdinand von Richthofen (better known as the Red Baron, a World War I flying ace). The word rhyolite comes from the Greek word rhà ½ax (a stream of lava) with the suffix -ite given to rocks. Rhyolite is similar in composition and appearance to granite, but it forms through a different process. Key Takeaways: Rhyolite Rock Facts Rhyolite is an extrusive, silica-rich igneous rock.Rhyolite has a similar composition and appearance to granite. However, rhyolite forms as a result of a violent volcanic eruption, while granite forms when magma solidifies beneath the Earths surface.Rhyolite is found all over the planet, but it is uncommon on islands located far from large land masses.Rhyolite takes many different forms depending on the rate at which the lava cools. Obsidian and pumice are two very different types of rhyolite. How Rhyolite Forms Rhyolite is produced by violent volcanic eruptions. During these eruptions, the silica-rich magma is so viscous that it does not flow in a river of lava. Instead, the volcano is more likely to explosively eject material. While granite forms when magma crystallizes beneath the surface (intrusive), rhyolite forms when lava or ejected magma crystallizes (extrusive). In some cases, magma partially solidified into granite may be ejected from a volcano, becoming rhyolite. The eruptions that produce rhyolite have occurred throughout geologic history and all over the world. Given the devastating nature of such eruptions, it is fortunate that they have been rare in recent history. Only three rhyolite eruptions have occurred since the beginning of the 20th century: the St. Andrew Strait volcano in Papua New Guinea (1953-1957), the Novarupta volcano in Alaska (1912), and Chaità ©n in Chile (2008). Other active volcanoes capable of producing rhyolite include those found in Iceland, Yellowstone in the United States, and Tambora in Indonesia. Landmannalaugar in Iceland showcases the many colors taken by rhyolite. Daniel Bosma / Getty Images Rhyolite Composition Rhyolite is felsic, which means it contains a significant amount of silicon dioxide or silica. Usually, rhyolite contains greater than 69% SiO2. The source material tends to be low in iron and magnesium. The rocks structure depends on the cooling rate when it formed. If the cooling process was slow, the rock may consist mostly of large, single crystals called phenocrysts, or it may be composed of a microcrystalline or even glass matrix. Phenocrysts typically include quartz, biotite, hornblende, pyroxene, feldspar, or amphibole. On the other hand, a quick cooling process produces glassy rhyolites, which include pumice, perlite, obsidian, and pitchstone. Explosive eruptions may produce tuff, tephra, and ignimbrites. Although granite and rhyolite are chemically similar, granite often contains the mineral muscovite. Muscovite is rarely found in rhyolite. Rhyolite may contain much more of the element potassium than sodium, but this imbalance is uncommon in granite. Properties Rhyolite occurs in a rainbow of pale colors. It can have any texture, ranging from a smooth glass to a fine-grained rock (aphanitic) to a material containing obvious crystals (porphyritic). The hardness and toughness of the rock is also variable, depending on its composition and the rate of cooling that produced it. Typically, the rocks hardness is around 6 on the Mohs scale. Rhyolite Uses Starting about 11,500 years ago, North Americans quarried rhyolite in what is now eastern Pennsylvania. The rock was used to make arrowheads and spear points. While rhyolite may be knapped to a sharp point, it is not an ideal material for weapons because its composition is variable and it readily fractures. In the modern era, the rock is sometimes used in construction. Gems commonly occur in rhyolite. The minerals form when lava cools so quickly that gas becomes trapped, forming pockets called vugs. Water and gases make their way into the vugs. Over time, gem-quality minerals form. These include opal, jasper, agate, topaz, and the extremely rare gem red beryl (red emerald). Fire opal precipitates in rhyolite vugs. Coldmoon_photo / Getty Images Sources Farndon, John (2007). The Illustrated Encyclopedia of Rocks of the World: A Practical Guide to Over 150 Igneous, Metamorphic and Sedimentary Rocks. Southwater. ISBN 978-1844762699.Martà ­, J.; Aguirre-Dà ­az, G.J.; Geyer, A. (2010). The Grà ©ixer rhyolitic complex (Catalan Pyrenees): an example of Permian caldera. Workshop on Collapse Calderas – La Rà ©union 2010. IAVCEI – Commission on Collapse Calderas.Simpson, John A.; Weiner, Edmund S. C., eds. (1989). Oxford English Dictionary. 13 (2nd ed.). Oxford: Oxford University Press. p. 873.Young, Davis A. (2003). Mind Over Magma: The Story of Igneous Petrology. Princeton University Press. ISBN 0-691-10279-1.

Crisis Management Planning - 579 Words

Sport is believed to be a unique â€Å"product†, since the majority of its images and messages get conveyed via the coverage by the media rather than through sales advertising. While this coverage is typically positive, the interest of the media gets more difficult as high profile scandals take place, which can be rather damaging. Therefore, a relevant public relations crisis response plan needs to be developed. A brief overview of the current writings on the issue exposes the need of crisis management planning to be â€Å"quick, be consistent, and be open† (Coombs, 2006, p. 172). First of all, a consistent message should be delivered by either one or more spokespersons, so that the information vacuum does not get filled with incorrect information. This step, done with maximum speed, will help to support believability (Coombs, 2006). Further, the emphasis should be on truthfulness as well as openness, especially in cases when an organization has erred. For example, Fearn-Banks (1996) argues that if some organization has erred, it had better revealed its mistakes immediately, apologize, and also make necessary amends. Fearn-Banks explains this by the fact that cover-ups will only lead to persistence of the crisis (Fearn-Banks, 1996, p. 65). This view is supported by a public relations expert Devon Blaine, who says that â€Å"openness with the press and honesty are the best practices†. It to apply this view to the situation of sports public relations crisis situation, in practice it mayShow MoreRelatedThe Johnson And Johnson Tylenol Crisis1331 Words   |  6 Pagesoverview about the â€Å"Johnson and Johnson Tylenol Crisis†. It gives an outline about the major communication activities (written and oral) conducted by our (Tylenol) crisis management team during our national response campaign for presenting the factual scenario of the crisis to the public and other several institutions. 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Life of the marine engineer free essay sample

Why did you become interested in Marine Engineering? Answer: This is my first choice. A practical course not only at sea base but also in land base. 2- Have you always wanted to be a marine engineering? What made you became a marine engineer? Answer : Yes, i always wanted to be a marine engineer because you will learn many things not only mechanical but also some skills. 3 –What is the best part of your job? Answer: Overhauling and trouble shooting because it is challenging. 4- What task does your specific job involve? Answer: More in mechanical job and operate machines. 5- What physical condition must you be in? Answer- You must be always physically fit and mental allert. 6- Would you recommend this career to any student? Answer: Yes, i will tell them the practicality of this course marine engineering. 7- Do you have any tips or advice on becoming a marine engineer? Answer: To be a marine engineer you must be hardworking, have work ethics, patient, discipline,initiative and continous learning. We will write a custom essay sample on Life of the marine engineer or any similar topic specifically for you Do Not WasteYour Time HIRE WRITER Only 13.90 / page 8- How long have you been a marine engineer? Answer: 8 years 9-How much time do you spend on ships? Answer: That depends on the company or the type of work. Generally, as an officer, you get one day off the ship for everyday worked. Right now i work 14 weeks away working on a ship, then I go home for 14 weeks. 10- Do you design new equipment for ships? Answer: Currently no. I work on a cruise ship on the operational side of things, so just maintaining the machine is a big enough job. We always have some improvements to machines designs or processes but these are usually minor in nature. Engineering Disasters Humankind has achieved great engineering feats, from underwater tunnels to skyscrapers, yet for all its intelligence, it is still far from infallible. We often hear news of engineering disasters and they are bound to happen because like humans, technology too is evolving and it is not perfect. Engineering disasters occur because of flaws in design, human error, and certain uncontrollable situations. The Chernobyl nuclear disaster occurred because of deficiencies in the design and not sticking to guidelines. On the other hand, the World Trade Centers internal structure failure was not because of debris load, but the collapse was caused by fire alone. While constructing a building, tunnel, or a bridge, engineers always plan and design considering few important aspects that could affect the engineering structure in the real-time. For instance, a bridge would be designed considering traffic density for the next ten or fifteen years, earthquake loads, and hydrostatic pressure. Now it is not possible for a human mind to plan and design for unseen situations that might arrive in the future. No one would have expected the World Trade Center to collapse because of excessive heating despite the presence of fireproof systems well in place. Through this guide to engineering disasters, we will discuss some of the not so popular engineering disasters of the recent times and look also at recorded human responses when things suddenly go badly wrong. Failed Bridges Across the World Bridge failures affect our connectivity, and if the bridge fails at a remote location, places might be isolated from the main land or other regions for a long period of time. For instance, the Tay Bridge in Scotland was destroyed when a violent storm hit the bridge. Its destruction was due to design failure as well as problems with construction. We have listed a few articles here that cast light on the cause and effect of failed bridges. Does anybody knows hows life of a marine engineer on ship? Life aboard a large seagoing vessel is a lot of work. As a licensed mariner Im sure he is working 4 hours on watch and 8 hours off, plus whatever overtime he has to work everyday. Life at sea becomes very routine, you stand your watch, you work your ot, you nap, shower, eat, stand watch, and repeat. Depending on the type of vessel he sails aboard will dictate how busy he is when the ship pulls into a port. With the invention of the shipping container, ships are rarely in port for more than 24 hours. Shipping has become extremely efficient, and usually its offload, onload, gas up, restock the galley and good bye. If his vessel is not equipped with the internet then it will be very pricey to make telephone calls via satellite telephone. When the ship is inport he may not have the time to find a phone, or a stamp. Just as sailing isnt for everyone, having a relationship with a sailor isnt for everyone. You need to trust each other implicitly. Ultimately, you need to trust him, and he needs to trust you; bottomline. Additionally, you have to be strong and independent while he is gone and enjoy the time you get to spend with him while he is home. From a womans perspective life at sea is not the romantic lifestyle you see watching old movies its hard work, and it is very difficult on relationships, friendships, and on the person who is gone. He may not call or write you often but I can almost guarantee he is thinking of you more than you are of him. Its a hell of a lot lonelier out there for him, than it is for you you have friends and family around you, he has shipmates. Some of his shipmates can be his best friends and some may be his worst enemy. All I can say is, if you love him and want to be with him then offer the best support you can to him, appreciate that he is working his butt off, and dont let some other schmuck tempt you away from him just because he is gone a few months at a time. Trust me its not all that glamorous at sea He is working aboard a vessel that is moving a commodity from A to B, making sure all systems are working and fixing things when they break, hes not out there catering to supermodels chances are there are less than 3 females on his ship, if that many.

Mustard Seed Yellow free essay sample

The room was silentempty. I sat there waiting and worrying about what would happen next. Would the student stay attached to their parents? Will my class be big? Small? Loud? Silent? The first student arrives on my first day of teaching and I greet the parents with a smile. Before I realized it, it is me alone with 10 children, on our first day of Sunday school. My words are shaky and quiet. We all sit down at a child sized table, staring at a bin of markers and coloring sheets. Nervous of no response, I begin by asking all the students for their names and their favorite color. One brave little boy, short with blonde hair says his name is Tanner and, after asking the whole class shares their favorite colors, he begins to tell the class a story about why his favorite color is yellow. I suddenly find myself smiling as a wave of relief rushes over the classroom. We will write a custom essay sample on Mustard Seed Yellow or any similar topic specifically for you Do Not WasteYour Time HIRE WRITER Only 13.90 / page The class slowly builds off of Tanner’s story. A little boy named Ethan says he has an older brother and explains how his big soccer game is next week, while Regan informs me of her gluten free allergy and what that means for snacks in the class. As the conversation moves from student to student, I realize that its not just teaching and learning that makes me show up every Sunday, but the personal experiences and stories I get to hear from each child. After hearing Tanner confidently speak in a loud voice about his obsession with the color yellow, I change my lesson plans on the spot. Instead of teaching the story of Adam and Eve, I pull the story of the yellow mustard seed from the shelf. The story of the smallest mustard seed that grew into the greatest of the herbs, with coloring sheets and crafts, all revolved around Tanner. The excited students began to talk and speak of their favorite colors, or the stories and experiences they had in this class last year, such as the time they performed a skit of David and Goliath, or when they had blue Jell-O and sour patch kids signifying Jesus walking on water. The quiet little girls became social butterflies, and the roaring big boys learned to listen. Reagan talked more about her two sisters while Ethan, although eager to speak, stayed quiet. My lesson plans became customized and determined by the mood and topic of conversation in class. The students created their own class and way of learning while I learned that connecting with my students is the most important aspect of teaching. Tanners favorite color was no longer yellow. Instead it was the color of a mustard seed.