The Bowen Reaction Series in Geology

The Bowen reaction series is a description of how magmas minerals change  as they cool. The petrologist Norman Bowen (1887-1956) carried out decades of melting experiments in the early 1900s in support of his theory of granite. He found that as a basaltic melt slowly cooled, minerals formed crystals in a definite order. Bowen worked out two sets of these, which he named the discontinuous and continuous series in his 1922 paper The Reaction Principle in Petrogenesis. The Bowens Reaction Series The discontinuous series starts with olivine, then pyroxene, amphibole, and biotite. What makes this a reaction series rather than an ordinary series is that each mineral in the series is replaced by the next one as the melt cools. As Bowen put it, The disappearance of minerals in the order in which they appear ... is of the very essence of the reaction series. Olivine forms crystals, then it reacts with the rest of the magma as pyroxene forms at its expense. At a certain point, all the olivine is resorbed, and only pyroxene exists. Then pyroxene reacts with the liquid as amphibole crystals replace it, and then biotite replaces amphibole. The continuous series is plagioclase feldspar. At high temperatures, the high-calcium variety anorthite forms. Then as temperatures fall it is replaced by more sodium-rich varieties: bytownite, labradorite, andesine, oligoclase, and albite. As the temperature continues to fall, these two series merge, and more minerals crystallize in this order: Alkali feldspar, muscovite, and quartz. A minor reaction series involves the spinel group of minerals: chromite, magnetite, ilmenite, and titanite. Bowen placed them between the two main series. Other Portions of the Series The complete series is not found in nature, but many igneous rocks display portions of the series. The main limitations are the state of the liquid, the speed of cooling and the tendency of mineral crystals to settle under gravity: If the liquid runs out of an element needed for a particular mineral, the series with that mineral gets interrupted.If the magma cools faster than the reaction can proceed, early minerals can persist in partly resorbed form. That changes the evolution of the magma.If crystals can rise or sink, they stop reacting with the liquid and pile up somewhere else. All of these factors affect the course of a magmas evolution—its differentiation. Bowen was confident that he could start with basalt magma, the most common type, and build any magma from the right combination of the three. But mechanisms that he discounted—magma mixing, assimilation of country rock and remelting of crustal rocks—not to mention the whole system of plate tectonics he did not foresee, are much more important than he thought. Today we know that not even the largest bodies of basaltic magma sit still long enough differentiate all the way to granite.

How to Use Flash Cards to Study Chemistry

Flash cards can be a great study aid. You can use them to help memorize facts, lists, and structures as well as to reinforce important concepts. Heres how to prepare and use flash cards to study. Learning Facts with Flash Cards Start with a stack of blank index cards.On one side of a card, write a question or name of a structure you need to memorize. On the back of the card, write the answer. Limit yourself to one fact per card.Prepare as many cards as you need.To use the cards effectively, view the question and quiz yourself. Do you know the answer? Check the back of the card. If you answered correctly, set the card aside. If you were wrong, place the card on the back of your stack so that you will see it again.Proceed through your stack of cards. Set aside cards you get right and continue through cards you get wrong until you have gotten all questions/answers correct.Now shuffle the cards and repeat the process.Practice makes perfect, so if you get frustrated, set the cards aside and come back to them. Go through your cards every day (or more often, if you are cramming). Memorizing a List with Flash Cards If you are memorizing an ordered list, try to guess the next card before you look at it. Continue through your list until you get a wrong answer.With the cards in the same order, start from the beginning and go through the cards to see if you can get further.For long lists, it may help to break the list up into manageable pieces, such as three smaller stacks of cards. Once you get the smaller stacks correct, put them together and see if you can recite the entire list.

Henrik Wolff The Dead End Of Western Civilization

The words that we use in every day conversation help us to convey a message to whoever we are speaking to. Words are used in order to evoke a reaction, or create a lasting effect on whoever is receiving them. Authors determine the words they want to use by organizing their arguments or main points. In both Hipster: The Dead End Of Western Civilization by Douglas Haddow, and Bullet in the Brain by Tobias Wolff, the authors choose to make use of intellectual diction in order to indicate the idea that an absence of spontaneity is holding society back. In Bullet in the Brain by Tobias Wolff, main character Anders is described as being sarcastic, cynical, and argumentative. Anders is a very serious man who has been through a lot of hardships in his life that have made him the cynical man that he is today. Because he is a book critic, no matter what situation, Anders critiques everything that occurs around him. â€Å"Anders had never paid much attention to that part of the bank, a pompous old building with marble floors and counters and pillars, and gilt scrollwork over the tellers cages. The domed ceiling had been decorated with mythological figures whose fleshy, toga-draped ugliness Anders had taken in at a glance many years earlier and afterward declined to notice. Now he had no choice but to scrutinize the painter s work (Wolff,  ¶.26).† This quote directly shows what kind of a person Anders is. Even in the face of danger, he is still being his normal self. Anders has a gun to

hamlet, edgar sawtelle contrast Essay Example For Students

hamlet, edgar sawtelle contrast Essay Brittany Travers MS. OBrien English IV 18 January 2013 Comparative Essay In the drama of Hamlet and the novel The Story of Edgar Sawtelle there are many similarities. One of the most interesting similarities being, the relationship between Hamlet and Horatio, and Edgar and Almondine. They both reflect on the loyalty, protection and support shown in each writing. In Shakespeares drama Hamlet, Horatio and Hamlet have been best friends since there childhood years and have been ever since. In Wroblewskis novel, The Story of Edgar Sawtelle, Edgar and Almondine have been inseparable since the birth of Edgar, with the locality of Edgar being born mute. All of which are displayed in the novel The Story of Edgar Sawtelle, and the drama Hamlet. In the drama Hamlet, Horatios loyalty is rock-steady throughout the play. So much that he is Hamlets only true confidant. Horatio, being Hamlets one and only best friend is the one to tell him that the watchmen have seen a ghost resembling his father. After revealing the news to Hamlet they then go together to see the ghost and are sworn to secrecy about the ghosts appearance. This is one situation in the drama f Hamlet where loyalty is displayed. In Wroblewskis novel, loyalty is shown through the communication of Edgar and Almondine. Knowing Edgar is disabled, Almondine is trained to help him find a way of communicating. With Edgar being born mute, they speak through what is called sign. This shows his loyalty through Almondine sticking by his side. In the scene of the fght with Hamlet and Laertes, Horatio warns Hamlet not to take part in the friendly duel that Claudius and Laertes have arranged. By telling Hamlet this, Horatio is looking out for his best interest and trying to keep both of them safe. Also in the tragedy Hamlet, the bond with both friends is shown in the plays ending. Horatio offers to commit suicide when his beloved Hamlet is dying before him. Hamlet insists, however, Horatio lives to tell the tragic story, and he does so. This is the upmost way of showing Horatios protective instinct for his best friend Hamlet. During The Story of Edgar Sawtelle, Almondine also shows his loyalty through the findings of Edgar after he leaves to the Chaquemegon Forest. Usually dogs will lie around and die of a broken heart, but Almondine, a dog with some degree of hope about the world ends up looking around. Almondine chooses the latter. She begins to search, not Just for Edgar but for a solution to the whole dilemma of being without Edgar, about being separated from ones purpose in life, to help him communicate. This is something larger and more intelligent than physical separation. A question that Edgar himself happens to encounter with at that moment. In conclusion, there are many similarities in both the novel The Story of Edgar Sawtelle and the drama Hamlet with the comparison of loyalty between Edgar and Almondine, and Horatio and Hamlet. hamlet, edgar sawtelle contrast By btraversl 5