Full Answer
What does differentiation mean in geology?
This chemical separation by partial melting and outgassing of volatiles is termed differentiation. As the interior differentiated, less-dense liquids rose from the melt toward the surface and crystallized to form crust.
Is geology a good field to major in?
Yes, geology is an outstanding major, both now and for the future. However, to be continuously employed and professionally successful, you need to make yourself into a very good geologist who is in demand because of your technical skills and knowledge.
What is differentiation in planetary geology?
Planetary differentiation is the separation of different constituents of planetary materials resulting in the formation of distinct compositional layers. Denser material tends to sink into the center and less dense material rises toward the surface.
What is uniformitarianism in geology?
uniformitarianism, in geology, the doctrine suggesting that Earth’s geologic processes acted in the same manner and with essentially the same intensity in the past as they do in the present and that such uniformity is sufficient to account for all geologic change.
What is the process of differentiation geology?
When planets begin to melt, the materials in them begin to separate from one another. The heaviest materials, such as metallic iron, sink to form cores. Low-density magmas rise, forming crusts. This process is called differentiation.
What happened during Earth's differentiation?
The differentiation, or organization, of the Earth into layers is perhaps the most significant event in its history. It led to the formation of a core, a crust, and eventually continents. The light elements were driven from the interior to form an ocean and atmosphere. These four blocks are the same size.
What are the three phases of Earth's differentiation?
The Earth's differentiation describes its formation into layers, which include its iron-rich solid inner core, its molten outer core, its solid mantle and its crust on which we live.
What caused the differentiation of Earth's layers?
The differentiation between these layers is due to processes that took place during the early stages of Earth's formation (ca. 4.5 billion years ago). At this time, melting would have caused denser substances to sink toward the center while less-dense materials would have migrated to the crust.
What is differentiation in planetary geology quizlet?
What is differentiation in planetary geology? The process by which gravity separates materials according to density.
How would you differentiate the layers of Earth?
Earth can be divided into three main layers: the core, the mantle and the crust. Each of these layers can be further divided into two parts: the inner and outer core, the upper and lower mantle and the continental and oceanic crust. Both the inner and outer core are made up of mostly iron and a little bit of nickel.
How does the differentiation process generate heat?
Differentiation is heat generated by the energy released as dense objects fall toward the center of a planet during the formation of the core of a planet. Radioactive decay generates heat by releasing nuclear energy when an unstable (radioactive) isotope decays into a more stable element.
What is geochemical differentiation?
primary geochemical differentiation A theory explaining the formation of the Earth's core, mantle, and crust, in which the formation of the nickel—iron core may have been accompanied by partitioning of the elements.
What is meant by process of differentiation in geography?
The process of separation of lighter and denser material is called differentiation.
What processes contribute to the differentiation of the crust?
Perhaps the most important event for Earth's surface, however, was the formation of the earliest crust by partial melting of the interior. This che...
What happens during differentiation on Earth?
The differentiation, or organization, of the Earth into layers is perhaps the most significant event in its history. It led to the formation of a c...
What are the three phases of Earth's differentiation?
Definition. The Earth's differentiation describes its formation into layers, which include its iron-rich solid inner core, its molten outer core, i...
What is meant by the process of differentiation in geography class 11?
Answer: Starting from the surface to the central parts, we have layers like the crust, mantle, outer core and inner core. From the crust to the cor...
What is the differentiation of Earth?
The Differentiated Earth. Part of Hall of Planet Earth. The differentiation, or organization, of the Earth into layers is perhaps the most significant event in its history. It led to the formation of a core, a crust, and eventually continents.
What did light elements drive to form?
It led to the formation of a core, a crust, and eventually continents. The light elements were driven from the interior to form an ocean and atmosphere.
What is the process by which the Earth came to have its present interior structure?
The Earth did not have the interior structure described in the preceding section when it was formed. The geological process by which the Earth came to have its present interior structure is called differentiation, and is illustrated in the following figure.
Why did the Earth's outer layers crack?
As the outer layers cooled and solidified, large cracks developed because of thermal stress, leaving the lithosphere broken up into large blocks or plates.
What is the process of igneous differentiation?
In geology, igneous differentiation, or magmatic differentiation, is an umbrella term for the various processes by which magmas undergo bulk chemical change during the partial melting process, cooling, emplacement, or eruption. The sequence of (usually increasingly silicic) magmas produced by igneous differentiation is known as a magma series .
How to determine magma differentiation?
In all cases, the primary and most valuable method for identifying magma differentiation processes is mapping the exposed rocks, tracking mineralogical changes within the igneous rocks and describing field relationships and textural evidence for magma differentiation . Clinopyroxene thermobarometry can be used to determine pressures and temperatures of magma differentiation.
What is the term for the formation of fractional crystals during differentiation?
Fractional crystallization and accumulation of crystals formed during the differentiation process of a magmatic event are known as cumulate rocks, and those parts are the first which crystallize out of the magma. Identifying whether a rock is a cumulate or not is crucial for understanding if it can be modelled back to a primary melt or a primitive melt, and identifying whether the magma has dropped out cumulate minerals is equally important even for rocks which carry no phenocrysts .
What causes magma to differentiate?
Most magmas are a mixture of liquid rock (melt) and crystalline minerals (phenocrysts). Contamination is another cause of magma differentiation. Contamination can be caused by assimilation of wall rocks, mixing of two or more magmas or even by replenishment of the magma chamber with fresh, hot magma.
How does fresh magma change the composition of the melt?
Fresh magma changes the composition of the melt, changing the chemistry of the phases which are being precipitated. For instance, plagioclase conforms to the liquid line of descent by forming initial anorthite which, if removed, changes the equilibrium mineral composition to oligoclase or albite. Replenishment of the magma can see this trend reversed, so that more anorthite is precipitated atop cumulate layers of albite.
Why is it important to find the composition of a magma series?
By finding the primitive magma composition of a magma series, it is possible to model the composition of the rock from which a melt was formed, which is important because we have little direct evidence of the Earth's mantle.
What is a composition from which they could reasonably be produced by fractional crystallization?
A composition from which they could reasonably be produced by fractional crystallization is termed a parental melt. To prove this, fractional crystallization models would be produced to test the hypothesis that they share a common parental melt.
Which branch of differentiation is ferromagnesian?
This process of differentiation occurs along two branches: discontinuous and continuous. The discontinuous branch. The minerals that form in the discontinuous branch are all ferromagnesian —that is, they contain high percentages of iron and magnesium, which impart a dark green to black color.
What is the continuous branch of a mineral?
The continuous branch. The continuous branch is made up of the plagioclase feldspars. The calcium/sodium ratio in this mineral type changes continuously as the magma cools. The first feldspars to form contain the highest amounts of calcium; subsequent feldspars have progressively less calcium and more sodium.
What is the defining characteristic of igneous rocks?
Magmatic Differentiation. The defining characteristic of igneous rocks is that at one time they were molten and part of magmas or lavas. A magma is a body of molten rock that occurs below the surface of the earth. When magma rises along a deep fault and pours out on the earth's surface, it is termed lava. This material then cooled ...
What happens when a magma cools?
When a magma cools, chemical reactions occur that create a series of different minerals. This process of differentiation occurs along two branches: discontinuous and continuous. The discontinuous branch.
What is the term for the material that rises along a fault and pours out on the Earth's surface?
When magma rises along a deep fault and pours out on the earth's surface, it is termed lava. This material then cooled to form a variety of intrusive and extrusive igneous rocks. Extrusive rocks crystallized from liquid magmas that reached the surface and were generally vented as volcanic lavas.
Why is the continuous branch called discontinuous?
The branch is called discontinuous because the minerals form at discrete temperatures and not continuously during cooling. The first mineral to crystallize is olivine, followed by pyroxene, amphibole, and biotite. The continuous branch. The continuous branch is made up of the plagioclase feldspars.
Who discovered that magma crystallizes at the lowest temperature?
These theories were first proven in the laboratory by N. L. Bowen in the early 1900s and are also known as Bowen's reaction series.
Why are silicates concentrated in the mantle?
Because they can fit much more easily into the more open crystalline structures of silicate and oxide minerals, they are concentrated in crust and mantle. After partial melting and differentiation, the Earth would have also allowed the release of gaseous compounds formed and trapped in the interior.
When did the Earth form?
January 17, 2001 -- Scientists are drawing a portrait of how Earth looked soon after it formed 4.56 billion years ago, based on clues within the oldest mineral grains ever found.
How deep do iron drops form?
iron "drops" will begin to form. Because melting depends on a combi-. nation of pressure and temperature, the first drops form at a depth of. less than 500km. With more heating the zone of iron melting becomes. thicker. (3) The iron "drops" follow gravity and. accumulate towards the core.
How did radioactive decay affect the Earth?
1) radioactive decay of U, Th, and 40K produced a buildup of heat in the Earth interior (probably the most important contributor). The figure at right shows the heat generated by radioactive decay at various times in the past. The heat generation decreased over time because the abundance of radioactive elements diminished due to decay.
What were the consequences of the melting of iron?
The gradual heat increase had consequences. Once the melting temperature of iron was reached within the earth, the initially random mixture of dust particles and gases began to unmix and differentiate according to the density of the various materials involved. The melting of iron, also known as the "iron event" among geologists, was a major benchmark in early Earth development. The compositional and thermal stratification of the Earth that it produced are essential for many of the various aspects of Earth dynamics that we observe today (in particular plate tectonics, magnetic field).
How does magma evolve?
While cooling, the magma evolves in composition because different minerals crystallize from the melt. 1: olivine crystallizes; 2: olivine and pyroxene crystallize; 3: pyroxene and plagioclase crystallize; 4: plagioclase crystallizes. At the bottom of the magma reservoir, a cumulate rock forms. Fractional crystallization, or crystal fractionation, ...
Why is fractional crystallization important?
It is important in the formation of igneous rocks because it is one of the main processes of magmatic differentiation.
What are some examples of fractional crystallization?
Textures of rocks provide insights, as documented in the early 1900s by Bowen's reaction series. An example of such texture, related to fractioned crystallization, is intergranular (also known as intercumulus) textures that develop wherever a mineral crystallizes later than the surrounding matrix, hence filling the left-over interstitial space. Various oxides of chromium, iron and titanium show such textures, such as intergranular chromite in a siliceous matrix. Experimentally-determined phase diagrams for simple mixtures provide insights into general principles. Numerical calculations with special software have become increasingly able to simulate natural processes accurately.
How do solar systems form?
Solar systems begin with the collapse of a cloud of gas and dust. Material drawn to the centre forms a star, and the remainder forms a disk around the star. Material within the disk clumps together to form planets. In our solar system, rocky planets are closer to the Sun, and ice and gas giants are farther away.
How did the Earth get heated?
Early Earth was heated by radioactive decay, collisions with bodies from space, and gravitational compression. Heating melted Earth, causing molten metal to sink to Earth’s centre and form a core, and silicate melt to float to the surface and form the mantle and crust.
Why are rocky planets closer to the Sun?
This is because temperatures near the Sun were too high for ice to form, but silicate minerals and metals could solidify. 22.4. Earth’s First 2 Billion Years.
Overview
In geology, igneous differentiation, or magmatic differentiation, is an umbrella term for the various processes by which magmas undergo bulk chemical change during the partial melting process, cooling, emplacement, or eruption. The sequence of (usually increasingly silicic) magmas produced by igneous differentiation is known as a magma series.
Definitions
When a rock melts to form a liquid, the liquid is known as a primary melt. Primary melts have not undergone any differentiation and represent the starting composition of a magma. In nature, primary melts are rarely seen. Some leucosomes of migmatites are examples of primary melts. Primary melts derived from the mantle are especially important and are known as primitive melts or primitive magmas. By finding the primitive magma composition of a magma series, it is possi…
Underlying causes of differentiation
The primary cause of change in the composition of a magma is cooling, which is an inevitable consequence of the magma being created and migrating from the site of partial melting into an area of lower stress - generally a cooler volume of the crust.
Cooling causes the magma to begin to crystallize minerals from the melt or liquid portion of the magma. Most magmas are a mixture of liquid rock (melt) and crystalline minerals (phenocrysts).
Typical behaviours of magma chambers
It is worth reiterating that magma chambers are not usually static single entities. The typical magma chamber is formed from a series of injections of melt and magma, and most are also subject to some form of partial melt extraction.
Granite magmas are generally much more viscous than mafic magmas and are usually more homogeneous in composition. This is generally considered to be caused by the viscosity of the …
Quantifying igneous differentiation
There are several methods of directly measuring and quantifying igneous differentiation processes;
• Whole rock geochemistry of representative samples, to track changes and evolution of the magma systems
• Trace element geochemistry
See also
• Petrology – Branch of geology that studies the origin, composition, distribution and structure of rocks
• Flow banding – Bands or layers that can sometimes be seen in rock that formed from magma
• Layered intrusion
External links
• COMAGMAT Software package designed to facilitate thermodynamic modeling of igneous differentiation
• MELTS Software package designed to facilitate thermodynamic modeling of phase equilibria in magmatic systems.