The Earths Crust Everything You Need to Know

The Earths crust is an extremely thin layer of rock that makes up the outermost solid shell of our planet. In relative terms, its thickness is like that of the skin of an apple. It amounts to less than half of 1 percent of the planets total mass but plays a vital role in most of Earths natural cycles.   The crust can be thicker than 80 kilometers in some spots and less than one kilometer thick in others. Underneath it lies  the mantle, a layer of silicate rock approximately 2700 kilometers thick. The mantle accounts for the bulk of the Earth. The crust is composed of many different types of rocks that fall into three main categories: igneous, metamorphic and sedimentary. However, most of those rocks originated as either granite or basalt. The mantle beneath is made of peridotite. Bridgmanite, the most common mineral on Earth, is found in the deep mantle.   How We Know the Earth Has a Crust We didnt know the Earth had a crust until the early 1900s. Up until then, all we knew was that our planet wobbles in relation to the sky as if it had a large, dense core  -- at least, astronomical observations told us so. Then along came seismology, which brought us a new type of evidence from below: seismic velocity. Records of seismic waves allow seismologists to locate and measure the size of events like these, and to map the Earths internal structure. jamesbenet/Getty Images   Seismic velocity measures the speed at which earthquake waves propagate through the different materials (i.e. rocks) below the surface. With a few important exceptions, seismic velocity within the Earth tends to increase with depth.   In 1909, a paper by the seismologist Andrija Mohorovicic established a sudden change in seismic velocity -- a discontinuity of some sort -- about 50 kilometers deep in the Earth. Seismic waves bounce off it (reflect) and bend (refract) as they go through it, the same way that light behaves at the discontinuity between water and air. That discontinuity named the Mohorovicic discontinuity or Moho is the accepted boundary between the crust and mantle. Crusts and Plates The crust and tectonic plates  are not the same. Plates are thicker than the crust and consist of the crust plus the shallow mantle just beneath it. This stiff and brittle two-layered combination is called the ​lithosphere (stony layer in scientific Latin). The lithospheric plates lie on a layer of softer, more plastic mantle rock called the asthenosphere (weak layer). The asthenosphere allows the plates to move slowly over it like a raft in thick mud.   We know that the Earths outer layer is made of two grand categories of rocks: basaltic and granitic. Basaltic rocks underlie the seafloors and granitic rocks make up the continents. We know that the seismic velocities of these rock types, as measured in the lab, match those seen in the crust down as far as the Moho. Therefore were confident that the Moho marks a real change in rock chemistry. The Moho isnt a perfect boundary because some crustal rocks and mantle rocks can masquerade as the other. However, everyone who talks about the crust, whether in seismological or petrological terms, fortunately, means the same thing. In general, then, there are two kinds of crust: oceanic crust (basaltic) and continental crust (granitic). Oceanic Crust An illustration of oceanic crust. Dorling Kindersley/Getty Images   Oceanic crust covers about 60 percent of the Earths surface. Oceanic crust is thin and young -- no more than about 20 km thick and no older than about 180 million years. Everything older has been pulled underneath the continents by subduction. Oceanic crust is born at the mid-ocean ridges, where plates are pulled apart. As that happens, the pressure upon the underlying mantle is released and the peridotite there responds by starting to melt. The fraction that melts becomes basaltic lava, which rises and erupts while the remaining peridotite becomes depleted. The mid-ocean ridges migrate over the Earth like Roombas, extracting this basaltic component from the peridotite of the mantle as they go. This works like a chemical refining process. Basaltic rocks contain more silicon and aluminum than the peridotite left behind, which has more iron and magnesium. Basaltic rocks are also less dense. In terms of minerals, basalt has more feldspar and amphibole, less olivine and pyroxene, than peridotite. In geologists shorthand, oceanic crust is mafic while oceanic mantle is ultramafic. Oceanic crust, being so thin, is a very small fraction of the Earth -- about 0.1 percent -- but its life cycle serves to separate the contents of the upper mantle into a heavy residue and a lighter set of basaltic rocks. It also extracts the so-called incompatible elements, which dont fit into mantle minerals and move into the liquid melt. These, in turn, move into the continental crust as plate tectonics proceeds. Meanwhile, the oceanic crust reacts with seawater and carries some of it down into the mantle. Continental Crust Continental crust is thick and old -- on average about 50 km thick and about 2 billion years old -- and it covers about 40 percent of the planet. Whereas almost all of the oceanic crust is underwater, most of the continental crust is exposed to the air. The continents slowly grow over geologic time as oceanic crust and seafloor sediments are pulled beneath them by subduction. The descending basalts have the water and incompatible elements squeezed out of them, and this material rises to trigger more melting in the so-called subduction factory. The continental crust is made of granitic rocks, which have even more silicon and aluminum than the basaltic oceanic crust. They also have more oxygen thanks to the atmosphere. Granitic rocks are even less dense than basalt. In terms of minerals, granite has even more feldspar and less amphibole than basalt and almost no pyroxene or olivine. It also has abundant quartz. In geologists shorthand, continental crust is felsic. Continental crust makes up less than 0.4 percent of the Earth, but it represents the product of a double refining process, first at mid-ocean ridges and second at subduction zones. The total amount of continental crust is slowly growing. The incompatible elements that end up in the continents are important because they include the major radioactive elements uranium, thorium, and potassium. These create heat, which makes the continental crust act like an electric blanket on top of the mantle. The heat also softens thick places in the crust, like the Tibetan Plateau, and makes them spread sideways. Continental crust is too buoyant to return to the mantle. Thats why it is, on average, so old. When continents collide, the crust can thicken to almost 100 km, but that is temporary because it soon spreads out again. The relatively thin skin of limestones and other sedimentary rocks tend to stay on the continents, or in the ocean, rather than return to the mantle. Even the sand and clay that is washed off into the sea returns to the continents on the conveyor belt of the oceanic crust. Continents are truly permanent, self-sustaining features of the Earths surface. What the Crust Means The crust is a thin but important zone where dry, hot rock from the deep Earth reacts with the water and oxygen of the surface, making new kinds of minerals and rocks. Its also where plate-tectonic activity mixes and scrambles these new rocks and injects them with chemically active fluids. Finally, the crust is the home of life, which exerts strong effects on rock chemistry and has its own systems of mineral recycling. All of the interesting and valuable variety in geology, from metal ores to thick beds of clay and stone, finds its home in the crust and nowhere else. It should be noted that the Earth isnt the only planetary body with a crust. Venus, Mercury, Mars and the Earths Moon have one as well.   Edited by Brooks Mitchell

1. The AdministratorS Part In Staffing In An Association

1. The administrator s part in staffing in an association that has a HR office is talked about in this section. We have stressed that the staffing capacity ought to be a line administration work with managers assuming a noteworthy part. Staffing incorporates the choice, situation, introduction, preparing, advancement, and pay of workers. Obviously, various staffing exercises are taken care of by the HR office, yet there is a distinction between the expression duty and exercises. Even however the HR office will be of real help to the boss, most duties regarding the staffing capacity remain with line administration, particularly the managers. The HR office can help the administrator by keeping up work records, giving guidance in taking†¦show more content†¦It is a smart thought for the director to take a seat and converse with the new representative on the principal day. The new worker ought to be given correlated data about the organization, the office, approaches, and direct ions. He or she ought to be acquainted with kindred laborers, demonstrated the offices in the office, and maybe given a visit through different parts of the plant or office. Numerous directors incline toward an accomplished current worker do a great part of the introduction and preparing of another representative. Data can be passed to new representatives through the foundation of mentorships. B. Most representative introduction, preparing, and advancement endeavors must be given at work at the office level. Preparing and advancement of representatives is a ceaseless procedure, which starts with the main day that a worker comes to work; worker preparing and improvement ought to be a high need concern. The boss who procures somebody to fill a space and who does not dedicate much push to building up the representative most likely is somebody who does not perceive his or her own requirement for self-change and self-advancement. C. Even though the new worker may have certain abilities, the new representative must be prepared in the systems, strategies, and models of the office. Among the methodologies that can be utilized as a part of expansion to at workShow MoreRelatedMy Introductory On Public Administration1472 Words   |  6 Pagesemployed in all levels of government, across various fields including social welfare, financial administration, and human resources (Denhardt, 2014, p. 1). Despite the various type of public administration jobs that exist, the one thing all public administrators are required to do is to maintain a commitment to public service (Denhardt, 2014, p. 1). In order to better understand how public administrators are responsive to public interests, I was assigned the task of interviewing a professional inRead MoreTeacher Retention2799 Words   |  12 Pagesarguably the most imminent threat to the nation’s schools. 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Three additional Riordan production plants include locations inRead MoreInformation Technology Implementation Issues: an Analysis45771 Words   |  184 Pages.....................................................................page(s) ii Table of Contents ............................................................................ page(s) iii-iv Chapter 1: Introduction.................................................................. page(s) 1-15 †¢ Research Questions †¢ Problem Statement †¢ Purpose of Study †¢ Description of Issues †¢ Significance of Study Chapter 2: Literature Review....................................................... page(s)Read MoreAdvancing Effective Communicationcommunication, Cultural Competence, and Patient- and Family-Centered Care Quality Safety Equity53293 Words   |  214 Pages...........................vii Introduction ..........................................................................................................1 Terminology ........................................................................................................................................................................................1 A Roadmap to the Future .............................................................................................................................

Kafka Free Essays

string(74) " because without it we would feel worthless and needless to say, useless\." This simple yet ingenious quote by Kafka does make one stop and think, is life really that meaningless? How can one concur if life is meaningless or not? Before these questions can be answered, one must ask, what is meaning? Amazingly enough, meaning is something we create ourselves. We attach meaning to everything around us whether it be language, a person, an item, or even a pencil. Meaning comes from within us, making us the sole contributor to our own existence. We will write a custom essay sample on Kafka or any similar topic only for you Order Now Therefore, nothing has meaning unless one was to ttach meaning to it, and to attach meaning to anything proves one has created an identity, and that identity allows one to exist. Mortal life by definition comes to an end whether one likes it or not, and because of this, we are always facing the pressure of extinction. The way we cope with this pressure is by giving meaning to the things we do, the things we love, and all the other things which matters in ones life. To give ourselves an identity in which we exist in this world and to leave behind a trace of our existence. Although it is truly evident that meaning comes from within the individual, others might think differently. One of the main arguments against meaning coming from the individual is that we were already given meaning since birth, given a set of beliefs and morals to follow, so how does one create meaning if it was already given to us from generation through generation? What they do not know is that meaning is something we gain through experience, and experience is not something we have from birth. Another valid argument would be that this universe does not need meaning and therefore it is not important to have meaning or create meaning. However, meaning is all around us and whether one likes it or not, we were built to reate meaning in order for us to exist, and for us to be able to create an identity. Before we dive deeper into the topic of how we gain meaning, we first have to question what is meaning? Clare Carlisle quotes Kierkegaard and explains, â€Å"Even though all sorts of things exist, for Kierkegaard the word â€Å"existence† has a special meaning when applied to human life. This meaning arises from the fact that we always have a relationship to ourselves. † (Carlisle, What does it mean to exist? ) To go into more thorough detail, meaning is the stem of everything human. Meaning come rom us because like stated above in the quote by Kierkegaard, we are the only ones can have a relationship to ourselves. Humans only truly exist through identity, identity is gained through experience, and experience is what use to create meaning. Many other individuals would like to believe that meaning does not come within us, but rather given to us, passed down to us from our past generations. For an example, Annie Druyan, wife of astronomer/philosopher Carl Sagan (1934 – 1996) remembered a conversation her husband had with a young man and it goes, â€Å"At the end of it, a young man came up to him and he said: What do you give us in return? Now that you’ve taken everything from us? What meaning is left, if everything that I’ve been taught since I was a child turns out to be untrue? Carl looked at him and said, ‘Do something meaningtul. ‘ † (Sagan. ) Without meaning this world would b complete chaos. A person needs to grow up with meaning as a supporting factor, or else their world would become chaotic and by definition, meaningless. The young man in the flashback is a person who struggles with the belief that he grew up with meaning given to him and therefore once he comprehend the truth and reality of it all, there would be no significance left. Carl Sagan tries to make this young man understand that in truth, meaning is something we can create anytime, anywhere, and anyplace. Sagan’s simple and brief quote ‘Do something meaningful’ gives us hope because it illustrates that meaning does not stem from the beginning of our lives, but something we have to experience and something we have to do in order to gain meaning. Although there are many others out there like the young man depicted in Annie Druyan’s flashback, they would have to know that meaning is not something in which they are given, but is gained through their Journey and understanding of life. This is significant because it is imperative for ones knowledge to understand that no matter how lost or confused one might be, they could always create their own meaning instead of relying or is biased on the thought that meaning was created for us. If one was to be biased on that thought, their total reliance on the meaning at which was given to them would collapse when they learn the undeniable truth that meaning has always been within their reach. Although meaning is a controversial and conflicting topic to discuss, some might argue that meaning is something we shouldn’t try to understand at all. Alex Percival as a strong opinion towards meaning and how he believes the universe does not need meaning at all. He states in his own words, â€Å"With modern discoveries, we have found that the meaning of life itself is pointless, but we are extremely lucky to be here because the probability that any one of us being in existence is next to 0%. † (Percival. ) In truth, meaning does matter in this world that we live in. Without meaning we would be lost with no identity, and would have no proof of our own existence. It is important for humans to make meaning for themselves because we want to exist and therefore we should exist. Meaning is not pointless at all, in fact meaning is apart of ones soul, apart of us. Meaning is a tool we strive and depend on to survive, because without it we would feel worthless and needless to say, useless. You read "Kafka" in category "Papers" Despite the many oppositions against the interpretation of meaning, language is one of the many factors in which humans attach meaning to. One blogger give their thoughts on how meaning relates to language and states, â€Å"Language communicates meaning, and the origin of meaning is relationship. In fact; if we use the idea that â€Å"relationship is the origin of meaning† as our lens, it opens up a whole new world eyond the narrow definitions that confine meaning to traditional ideas of language. † (The Wisdom of Life. ) Language in fact does relate to human relationships. To be able to communicate and articulate our thoughts gives us meaning. Without language, humans would not be able to express their thoughts and empty their minds and this is an important process to meaning because how can one attach or create meaning if they cannot express themselves. It is crucial to understand that language does not get it’s meaning from others but it is something we attach to it. For n example, as Professor Jacoby has mentioned in class, â€Å"A chair does not have meaning unless we give it meaning. The word chair to another person could mean something much more significant or it could mean nothing depending who this person is and what significant attachment they have given to the chair. † (English 205 Lecture. ) Anyone can give meaning to anything as long as there is a special significance to it. This is how we gain existence and gain identity. It comes through our experience and how we see things in our own eyes and not through what has already been defined for us. When one speaks about language, often we question what is the significance of many languages in this world. As Noam Chomsky says in We Still Live Here, â€Å"A language is not Just words. It’s a culture, a tradition, a unification of a community, a whole history that creates what a community is. It’s all embodied in a language. † (Chomsky. Language is no longer Just words or different types of languages that people speak around the world, it is what set us apart from others. It is what defines us as a people, it gives us meaning. With many languages around the orld, one could feel lost or troubled because they are afraid they could lose their identity. Although that is definitely not the case, language could preserve ones true identity because with language comes a culture, a tradition, a comm unity, and a whole history. With all these factors combined, one can find their identity and create meaning to their lives in their own ways and form. To find ones own identity is truly important in terms of existence, and the only way to find ones identity is through finding meaning within themselves. Meaning also attaches itself to forms of exceptionalism, how we interpret and ruly follow this ideal belief is entirely up to the person. In one article by The Globalist, they proclaim, â€Å"And Americans can only be exceptional if we are well informed and willing to make hard choices and take risks. Apathy, ignorance and risk aversion are the death sentence of the American experiment. (The Globalist, The Idea of American Exceptionalism. ) This is not only true to Americans, but also other cultures around the world as well. To make one self â€Å"exceptional† the person needs to be able to make well informed decisions on their own accord and take risks by the ips of the their own fingers. This connects to meaning because the only way we can make our own decisions and take our own risks is by attaching our own meaning to what all of these things mean. To be exceptional does not necessarily translate to ignorance, it could also mean it is their only form of survival. To any culture around the world, their identity is found through their culture, history, tradition. They rely on these factors because it is what makes them special, unique, and superior from others. Just like how each of them have their own language, tradition, and beliefs, hey want to preserve this by giving it a name, American Exceptionalism, British Exceptionalism, and Greek Exceptionalism. This way, they have given meaning to these terms which in return protect their identities. As individuals we all have a specific responsibility to be fulfilled once we take our first breaths in this world. One specific sentence which caught my attention in the article by The Globalist was, â€Å"As citizens, we have a sacred duty to conserve government by the active † not passive † consent of the governed. † (The Globalist, The Idea of American Exceptionalism. Even if we are a citizen of American or not, it does not matter, because every human in this Earth has a specific duty, which is to do something meaningful so that can be remembered for what theyVe done. The government is depicted as powertul, and because we see them as powertul, we believe that meaning comes from the government. The governments rules and laws seem to constrain us, but in reality it’s constrictions is what tests our understanding of what meaning is. For an example, in The Trial, a relatable quote from the conversation between K. and the doorkeeper goes as this, â€Å"Everyone strives to reach he Law,† says the man, â€Å"so how does it happen that for all these many years no one but myself has ever begged for admit-tance? † The doorkeeper recognizes that the man has reached his end, and to let his failing senses catch the words roars in his ear: â€Å"No one else could ever be admitted here, since this gate was made only for you. I am now going to shut it. † (Kafka 256. ) In The Trial, it is Kafka’s intentions to make the court look so powerful, because in this way, K. is forced to look for meaning and search for his own identity instead of trying to search for significant meaning in others. In fact, the court is so powerful that they have already planned everything out for K. K. ‘s future was in their hands and yet he barely even realized this because he was transfixed on trying to get everyone else to help him when the answers was within him. This message is of vital importance to comprehend, because one must know that no matter how powerful the barrier maybe between the person and their journey to gain meaning is, their duty as a human allows them to conquer those obstacles and face their own challenges. In The Trial it is evident from the very beginning K. ‘s thoughts were always ethered to what others thought about him and his need to find meaning through them instead of himself. Whenever K. spoke, he would always pay close attention to others, as though their opinions and thoughts were crucial to him, † ‘Intrusive, thoughtless people! ‘ said K. s he turned back into the room. The supervisor may have agreed with him, at least K. thought that was what he saw from the corner of his eye. But it was Just as possible that he had not even been listening as he had his hand pressed firmly down on the table and seemed to be comparing the length of his fingers. † (Kafka 17. Throughout the Trial, K. is repeatedly focusing on what others think of him, how others does not give him attention, and how others gave him meaning. His mind was constantly affected by the whispers around him and it affected him to the point whereby he was utterly dependent on other people. Kafka’s mission was to make us understand that K. was trapped in the wrong place the whole time, in someone else’s mind. When a person is trapped in someone else’s thoughts, it would be hard for them to understand how important meaning is if they are constantly looking for meaning in the wrong place. One of the great meanings behind Kafka’s works was to question one specific word, â€Å"Meaning. † In the text, K. ‘s conversation with the Priest demonstrates how Kafka views the word meaning, miou look for too much help from people you don’t know,† said the priest disapprovingly, â€Å"and especially from women. Can you really not see that’s not the help you need? † (Kafka 252. ) Kafka used K. as a guide to help him search for or make meaning. K. is constantly seeking and depending on others to be able to survive and to exist in this world that the meaning to his life soon became xactly that; his reliance on others became his meaning of survival, to exist. Kafka wants us to know that meaning was not already given to us, but we make meaning. We give meaning to people, things, and everything around us so we can feel special, unique, and most importantly to teel I ike we exist. Katka also wants us to know that K was looking for meaning in all the wrong places and to learn from K. ‘s mistakes. K. looked for meaning through his reliance on others, when he was supposed to create meaning within himself. To exist, we first have to rely on our own thoughts and our own ideas. This significant because our thoughts and our own ideas is how meaning is created. If we do not create meaning through our own minds, we do not exist according to Kafka, and that is why K. ies (Kafka 271) at the end because he was not able to realize his whole life depended on someone else, and his sense of meaning came from the people around him as well which is what makes one exist. Although, this leads to the quote which was stated in the beginning of the essay, â€Å"The meaning of life is that it ends. â€Å"-Franz Kafka. No matter how a person tries define meaning or try to apprehend it, life does end. So why is meaning so important? Meaning not only gives us a sense of security and comfort from the chaotic world we live in, but it also serves as a backbone to our identity and our existence. By us giving meaning to anything and everything, it gives us a sense of comfort knowing that it is significant or in some ways meaningful to us therefore making us feel as though we exist because we gave meaning to something which never had meaning before it came into our lives. To exist, to give meaning, and to gain an identity is all part of what it means to be human. Meaning nowadays is interpreted in many different ways, but one theory seems to tand out more than the rest, and it’s that meaning comes from within each individual and not from an external source. We use meaning to create ourselves, find our identities, and sustain our existence through our lifetime. In these modern times, the word meaning has been modified to each persons own interpretations of what meaning is. The problem is, would meaning ever be completely defined? Or is it a word that us humans can attach our own meaning to? It is definitely something to think about as we progress further into the world of constant change and start to lose the roots of our identity and even our existence. How to cite Kafka, Papers

I Come in Peace free essay sample

Hi, who are you? I am nothing exceptional. In my community, some lead, some follow, and some just stand in the way. I am pretty obscure. Nice to meet you, I come from Earth. Where I am from, I have never held student office, have never organized a toy drive, and have never volunteered at the soup kitchen. I do not compose music and hold free concerts for the children, do not recycle weekly (I do, however, drive American.) I do not attend church weekly, adopt animals in my free time, nor live by Biblical quotes. I do not concern myself with planting trees on every inch of land, and my purpose in life does not include saving the dying whales. Being a role model, not only as a mentor to students of lower grade levels, but to an easily-influenced younger brother, may count; I must carefully execute every move. My rank in the top 3% of my class must surely say a tiny bit about mehard work? Dedication? Maybe even†¦a shred of intelligence? People say employment speaks a little. We will write a custom essay sample on I Come in Peace or any similar topic specifically for you Do Not WasteYour Time HIRE WRITER Only 13.90 / page I say it rather screams â€Å"competence, dependability, and efficiency.† Being a varsity swimmer is no big deal, either. It only means grueling practice every day of the school week, arriving home at ridiculous hours after meets, and still acing that test the next day. Or maybe the broad spectrum of the people with whom I associate highlights my sense of humor, open heart, and love for people. Surely, though, all this must not count, because my life goals do not include the rational hope of â€Å"saving the world† and being president of the school’s Cheese Club. I feel obligated to mention one more thing; I am a tad demandingI expect and strive for no less than excellence. I must add that I am also quite lenientIf I am not number one, I can somewhat deal with tying for first place. In all seriousness, being a part of the Earth community is tough and I bump around here and there, but I cherish each experience.