Metacognative learning strategies give you the tools to really learn the material in your courses not just get enough information to maybe get an A on the test. Metacognition is thinking about your thinking. Analyzing if your study methods are actually helping you reach your goals. How well you do in your classes is a direct reflection of your behavior. If what you are doing isn't getting you the grades you want, you must try something different! Dr. Saundra McGuire has created several steps that help students turn their grade around. She has had many students go from failing tests to getting A's after applying metacognition. In this video she talks about what metacognition is and how it can help students.
Watch this video on the Study Cycle to learn about the Study Cycle that Dr. McGuire and her staff at LSU put together. If you commit to these steps, you will learn much more efficiently and your learning will be more complete.
by Kristie Bradford, Professor of Geology
Sunday, October 9, 2016
Bowen's Reaction Series - Relationship between ignous rocks, minerals, and silica content
Bowen's Reaction Series
In the early 1900's, N. L. Bowen and others at the Geophysical Laboratories in Washington D.C. began experimental studies into the order of crystallization of the common silicate minerals from a magma. The idealized progression which they determined is still accepted as the general model for
the evolution of magmas during the cooling process.
The Principles that Bowen realized are as follows:
To summarize: Bowen determined that specific minerals form at specific temperatures as a magma cools. At the higher temperatures associated with mafic and intermediate magmas, the general progression can be separated into two branches (see below). The continuous branch describes the evolution of the plagioclase feldspars as they evolve from being calcium-rich to more sodium-rich. Plagioclase feldspar crystals have a core that is calcium-rich and a rim that is sodium-rich. The average composition of the calcium and sodium content in plagioclase feldspars will approximate the calcium and sodium composition of the magma.
In the early 1900's, N. L. Bowen and others at the Geophysical Laboratories in Washington D.C. began experimental studies into the order of crystallization of the common silicate minerals from a magma. The idealized progression which they determined is still accepted as the general model for
the evolution of magmas during the cooling process.
The Principles that Bowen realized are as follows:
- As a melt (the liquid portion of the magma) cools minerals crystallize that are in thermodynamic equilibrium with the melt (dissolution equals crystallization; if no equilibrium exists either crystallization will dominate [supersaturation], or dissolution will dominate [undersaturated]).
- As the melt keeps cooling and minerals keep crystallizing, the melt will change its composition.
- The earlier formed crystals will not be in equilibrium with this melt any more and will be dissolved again to form new minerals. In other words: these crystals react with the melt to form new crystals, therefore the name, reaction series.
- The common minerals of igneous rocks can be arranged into two series, a continuous reaction series of the feldspars, and a discontinuous reaction series of the ferromagnesian minerals (olivine, pyroxene, hornblende, biotite)
- This reaction series implies that from a single "parental magma" all the various kinds of igneous rocks can be derived by Magmatic Differentiation (see below)
To summarize: Bowen determined that specific minerals form at specific temperatures as a magma cools. At the higher temperatures associated with mafic and intermediate magmas, the general progression can be separated into two branches (see below). The continuous branch describes the evolution of the plagioclase feldspars as they evolve from being calcium-rich to more sodium-rich. Plagioclase feldspar crystals have a core that is calcium-rich and a rim that is sodium-rich. The average composition of the calcium and sodium content in plagioclase feldspars will approximate the calcium and sodium composition of the magma.
Igneous Rocks
Igneous rocks are rocks formed through the crystallization of magma either on the surface as volcanic (extrustive) rocks or deep underground as plutonic (intrusive) rocks. Remembering that at one time early in our Earth's history, the Earth was molten. When the Earth cooled, the minerals crystallized into igneous rocks. Therefore, the rock cycle on Earth, begins with magma.
Rocks are classified as igneous, metamorphic, and sedimentary based on origin. Classification schemes are designed to answer a specific question or to organize the objects of the classification scheme in groups for easier identification and understanding. Sometimes classification allows us to see patterns in data which can then lead to interpretations. Oftentimes it is just a system of organization to handle quantities of data that are two large to be examined individually. Within each rock type are further classification schemes to better understand how the rocks were formed.
Rocks are classified as igneous, metamorphic, and sedimentary based on origin. Classification schemes are designed to answer a specific question or to organize the objects of the classification scheme in groups for easier identification and understanding. Sometimes classification allows us to see patterns in data which can then lead to interpretations. Oftentimes it is just a system of organization to handle quantities of data that are two large to be examined individually. Within each rock type are further classification schemes to better understand how the rocks were formed.
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