Geochemistry Flashcards
1
Q
The study of the nature and distribution of chemical elements in rock and minerals
A
Geochemistry
2
Q
The application of basic chemistry to earth sciences
A
Geochemistry
3
Q
It is used for dating rocks by using the radioactivity of elements
A
Geochronology or Isotope Geochemistry
4
Q
Geochemistry was first coined by
A
Christian Friedrich Schonbein
5
Q
Chemistry professor from University of Basel in Switzerland, in 1838
A
Christian Friedrich Schonbein
6
Q
The first geochemist in the modern sense of the world of USGS in 1908
A
Frank W. Clarke
7
Q
Book written by Frank Clarke
A
The Data of Geochemistry
8
Q
He correlated the mineral formation and structure to its chemical composition
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Victor M. Goldschmidt
9
Q
Victor M. Goldschmidt studied at
A
University of Gottingen in Germany
10
Q
He stated the rational explanation of isomorphous substitution in crystals based on the capability of the radii and charges of the ions
A
Victor M. Goldschmidt
11
Q
Father of modern chemistry and crystal chemistry
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Victor M. Goldschmidt
12
Q
He proposed the classification of minerals according to preferred hosts
A
Victor M. Goldschmidt
13
Q
it is a rock loving mineral
A
Lithophile
14
Q
It is an iron loving mineral
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Siderophile
15
Q
It is an ore loving mineral
A
Chalcophile
16
Q
It is a gas loving mineral
A
Atmophile
17
Q
Goals of Geochemistry
A
- To know the distribution of the chemical element in the Earth and in the solar system
2 . To discover the causes for the observed chemical composition of terrestrial and extraterrestrial materials - To study the chemical reactions on the surface of the earth, in its interior and in the solar system around us
- To assemble this information into geochemical cycles and to learn how this cycle operated in the geologic past and how they maybe altered in the future
18
Q
A model of the evolution of the universe that postulates its origin from a hot, dense mass that expanded rapidly and cooled
A
Big Bang Theory
19
Q
In the Big Bang Theory the fundamental composition that eventually combined or nucleated to become organized into the nuclei of H and He
A
Quark Soup
20
Q
Clues of “expanding Universe”
A
- The “red shift” of spectral light emitted by distant galaxies - the use of “doppler Effect” calculations
2.The “cosmic Microwave Radiation” which is the energy of radiation produced at a specific wavelength when the universe was at temperatures greater than about 3000oK
21
Q
Hierarchy of Heavenly Bodies
A
> Cluster of Galaxies
Galaxies
Stars, Pulsars, and Black Holes
Planets
Satellites
Comets
Asteroids
Meteoroids
Dust Particles
Molecules
Atoms of H and He
22
Q
basin unit in the hierarchy
A
Star
23
Q
Produced by contraction of interstellar gases resulting in increase in temperature
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Main Sequence Stars
24
Q
Energy production by H fusion becomes possible and thus produces star
A
Main Sequence Stars
25
High Luminosity and High temperature stars
Blue Giants
26
Stars less massive than the sun
Red Dwarfs
27
Bigger than the sun and is formed by depletion of H in the core during the main phase; the energy production shifted from the core to the outer shell
Red Giants
28
How Red Giants are formed?
formed by depletion of H in the core during the main phase; the energy production shifted from the core to the outer shell
29
End stage of stellar evolution
Pulsars (neutron stars), White Dwarf and Black Holes
30
Contraction leads to the increase in core temperature and eventually explodes to form the supernova
Pulsars (neutron stars), White Dwarf and Black Holes
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The star cycle begins again
Pulsars (neutron stars), White Dwarf and Black Holes
32
The theory that explains the complexation of material from the simple structure of H and deuterium (isotope of H)
Nucleosynthesis
33
First 4 statement in Nucleosynthesis
1. H and He are the most abundant isotopes in the universe
2. The abundances of the first 50 elements decreases exponentially
3. The abundances of the elements having atomic numbers greater than 50 are very low and do not vary appreciably with increasing atomic number
4. Elements with even atomic numbers are more abundant than immediate neighbors with odd atomic numbers
34
Last 4 statements in Nucleosynthesis
5. The abundances of Li, Be, and B are anomalously low compared to other elements of low atomic number
6. The abundance of Fe is notably higher than those of other elements with similar atomic numbers
7. Tc and Pm do not occur in the solar system because all of their isotopes are unstable and decay rapidly
8. The elements having atomic number greater than 83 (Bi) have no stable isotopes, but occur naturally at very low abundances because they are daughters of long - lived radioactive isotopes of U and Th
35
Diffuse mass of interstellar gas and dust
Solar Nebula
36
Condensates accreted to form larger bodies as a result of selective adhesion caused by electrostatic and magnetic forces
Planetisimals
37
High density, small planets
Terrestrial planets
38
Low Density, Large planets
Jovian Planets
39
Volatile rich planetisimals composed of water, ammonia, methane and other volatiles
Cometisimals
40
Diagram that shows the luminosity and temperature of the star
Hertzsprung-Russell Diagram
41
Chuck of rock from space that land on Earth
Meteorites
42
Kind of Meteorites
> Iron
> Stones
> Stony-irons
43
Predominantly Ni-Fe alloys Minor amounts of other minerals such as Troilite (FeS)
Iron Meterorites
44
Iron meteorites are classified according to ________________
% of Ni
45
Hexahedrite, Octahedrite and Ataxite are examples of what meteorite
Iron Meteorites
46
Chiefly Silicates, mostly ferromagnesian Up to 1/4 metallic
Stony Meteorites
47
Types of stone meteorites
1. Chondrites
2. Achondrites
48
Meteorites that contain chondrules
Chondrites
49
Meteorite composed chiefly of silicates such as olivine pyroxene, and plagioclase or glass important type
Carbonaceous Chondrite
50
High content of volatiles, including water and non biogenic carbon (will later show how determined to be non-biogenic)
Chondrites
51
Meteorite that have some composition as Sun's atmosphere
Chondrites
52
Meteorite that has no chondrules
Achondrites
53
Meteorite that has the same composition as terrestrial mafic and ultramafic rocks
Achondrites
54
Most __________ are breccias
Achondrites
55
Equal amounts of silicates and Ni-Fe alloys
Stony-iron meteorites
56
Many are crystallized silicates which have been brecciated, then invaded by metallic and sulfide melts
Stony-iron meteorites
57
Stony- iron meteorites classified according to kind of silicates: Olivine
Pallasite
58
Stony- iron meteorites classified according to kind of silicates: Plagioclase, Pyroxene
Mesosiderite
59
Components of an atom
1. A nucleus at the center, containing nearly all of the mass of their atom but accounting for only ten- thousandth of its diameter
2. A family of electrons gathered around the nucleus, forming three dimensional clouds that makes up the volume of an atom
60
Protons are ___________X more massive than electron
1825X
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Denotes any of the more than 1300 different atomic forms characterized by a distinct combination of protons and neutrons
Nuclide
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Only about 270 of which are stable
Nuclide
63
Composed of positively charged protons and neutrons, particles of nearly equal mass but of zero charge
Nucleus
64
First 3 general facts about atomic structure and property
1. Only 10 elements - H, He, C, N, O, Ne, Mg, Si, S, and Fe - all with atomic numbers less than 27, shows appreciable abundance. Of these H and He far outweigh the other 8
2. Abundance show a rapid exponential decrease for elements of the lower atomic numbers, followed by an almost constant value for heavier elements
3. Elements adjacent to Helium like Li and Be are very low in relative abundance
65
Last 3 general facts about atomic structure and property
4. Elements of even atomic number are more abundant than those of odd atomic number on either side. This regularity was first coined by Oddo and Harkins and is sometimes referred to as the Oddo Harkins Rule
5. Isotopes with mass numbers which are multiples of 4 (alpha particle mass number) have enhanced abundances
6. There is a pronounced abundance peak at atomic number 26 and smaller peaks at several other heavier atomic numbers such as oxygen
66
Elements of even atomic number are more abundant than those of odd atomic number on either side.
Oddo-Harkins Effect
67
Play the crucial role of overcoming the repulsive forces between protons, thus binding the nucleus to a tight structure.
Neutron
68
Refers to the number of proton in an atom of an element; it is the same for any atom of the element; this number serves to distinguish an element from another
Atomic Number (Z)
69
The average mass of the atoms of an element; to a close approximation, the number of protons plus the number of neutrons in an atom of an element
Atomic Mass (A)
70
The sum of the masses of its naturally occurring isotopes weighted in accordance with their abundances
Atomic Weight
71
Variation in atomic masses due to difference in the number of neutrons of an element
Isotopes
72
Nuclides having constant mass number but a different atomic number
Isotones
73
Nuclides having the same atomic mass but different neutron number and atomic number
Isobars
74
A region surrounding the nucleus occupied by electrons having approximately the same energy
Electron shell
75
Charge deficiencies that result from the substitution of ions of unequal charges must be compensated by a second substitution involving an ion having a different charge; the processes contributed to the diversification of chemical composition of many minerals
Coupled Substitution
76
An alternative to coupled substitution in which ions are attached on the charged surfaces of small ions; usually displayed by the clay minerals.
Adsorption
77
This occurs when the minor element has the same charge and a similar atomic radius as the major element it is replacing
Camouflage
78
This takes place when a minor element enters a crystal preferentially because it has a higher ionic potential than the ions of the major element
Capture
79
This involves the entry of a foreign ion that has a lower ionic potential than the major ion because it has either a lower charge or a larger radius, or both
Admission
80
The extent to which ions are admitted into a particular lattice site decreases as the difference in radii of competing ions increases
Admission
81
Possesses lowest potential energy possible for the mineral
Stable
82
Possesses the highest potential energy
Unstable
83
Requires an energy hurdle to put in the most stable form or of lower potential energy.
Metastable
84
Reveals or shows the ranges of stability in
pressure-temperature space (or in any possible physical , chemical, or mineralogical) parameters.
Phase Diagram
85
Areas representing the range of applied pressure and temperature in which a mineral may exist in its stable form.
Stability Fields
86
The line separating the various stability fields and defines a restricted set of circumstance under which the separated phase coexist in equilibrium.
Phase Boundary
87
Energy required for transformation to take place and is represented by the height of the energy hurdle.
Activation Energy
88
Concerned on the free energy changes associated with chemical equilibrium between phases, and provides the tools for working out which mineral assemblages will be stable under which conditions.
Thermodynamics
89
Deals with the mechanics of the reactions that lead to equilibrium, and the rates at which they occur.
Chemical Kinetics
90
A part of the universe which we wish to confine attention or whose properties are under consideration; the system is separated from its surroundings by a boundary whose properties
can be defined.
System
91
One that is free to exchange both matter and energy with the surroundings.
Open System
92
One that is sealed with respect to the transfer of matter, but that can still exchange energies with its surroundings.
Closed System
93
One that is capable of exchanging neither mass or energy with its surroundings.
Isolated System
94
A part or parts of a system occupying a specific volume and having uniform physical and chemical characteristics which distinguishes it from all other parts of the system.
Phase
95
Comprise the minimum number of chemical (atomic and molecular) species required to specify completely the compositions of all the phases present.
Components
96
All parts of the system have the same temperature; there is no net transfer of heat.
Thermal Equilibrium
97
The distribution of components among the phases of a system has become constant, showing no net change with time.
Chemical Equilibrium
98
The diffusion rates of an element in and out of the crystal are unequal; there will be a net change of composition of each phase with time.
Disequilibrium
99
For every element present the flux of atoms across the crystal boundary is the same in both directions resulting in zero net flow, and no change of composition in time.
Equilibrium
100
A formula which expresses the number of phases that can coexist in mutual equilibrium in terms of the number of components in the system and another property of the equilibrium called the variance; the variance is also known as the number of degrees of freedom.
The Phase Rule
101
(Variance of 0) Means that the three phase equilibrium assemblage completely constrains the state of the system to a particular combination of P and T.
Invariant
102
One degree of freedom indicates that the state of the system is only unconstrained in one direction which is along the phase boundary.
Univariant
103
The pressure and the temperature can vary independently (two degrees of freedom) without upsetting the equilibrium phase
assemblage.
Divariant
104
Is the locus of temperatures (a curve on a phase diagram) below which a given substance is completely solid (crystallized).
Solidus
105
The temperature above which a material is completely liquid, and the maximum temperature at which crystals can co- exist
with the melt in thermodynamic equilibrium
Liquidus
106
The point on a phase diagram where the maximum number of allowable phases are in equilibrium.
Eutectic Point
107
When this point is reached, the temperature must remain constant until one of the phases disappears
Eutectic Point
108
A eutectic is a/an ______________ point
Invariant
109
The point on a phase diagram where a reaction takes place between a previously precipitated phase and the liquid to produce a new solid phase.
Peritectic Point
110
When this point is reached, the temperature
must remain constant until the reaction has
run to completion.
Peritectic Point
111
Peritectic is a/an ________ point
Invariant
112
A phase that has a composition intermediate between two other phases
Intermediate Compound
113
melting wherein a phase melts to a
liquid with the same composition as the solid
Congruent Melting
114
melting wherein a phase melts to a liquid with a composition different from the solid and produces a solid of different composition to the original solid.
Incongruent melting
115
Usually measured in percentage (either mass or molar), and are commonly above 1% of the chemical composition of the material
Major Elements
116
Elements that occur in such small concentrations that they do not change the essence of what a material is. usually < 0.1%
Trace Elements
117
Are everything in between. Technically, this means things between 1% and 0.1%.
Minor Elements
118
Ions that do not fit into the structure of the rock-forming minerals or minerals precipitating in the magma at the time when ions are present and therefore accumulate as
in the residual magma
Incompatible Elements
119
______________ are concentrated in the late-stage differentiates of magmas, including aplites dikes, pegmatites, and hydrothermal veins.
Incompatible Elements
120
ions easily accommodated in the mineral structure
Compatible Elements
121
Magma derived from the mantle with Fo# 88
to 92, Mg # of 65 and above, and low Cr#
Primitive Magma
122
First magma derived from primitive magma.
Primary Magma
123
Primary Magma can be classified as
Parental Magma
124
Derived primarily by partial melting of the same source and have no characteristics that reflect the subsequent effects of differentiation
Primary Magma
125
Are not necessarily primitive nor primary but
where other magmas derived.
Parental Magma
126
In Rb/Sr the one incompatible to melt is _______
Rb
127
In Sm/Nd the one compatible to melt is _______
Sm
128
Fertile Unaltered mantle
Lherzolite
129
Refractory residuum after basalt has been extracted by partial melting
Dunite and Harzburgite
130
High concentration of NiO in magma composition shows
Mantle origin
131
Low concentration of NiO in magma composition shows
Cumulate
132
High concentration of TiO2 in magma composition shows
MOR derived or Mid Oceanic Ridges Derived
133
Low concentration of TiO2 in magma composition shows
Island Arc Derived
134
Separates the subalkaline from the
alkaline fields at low P
Thermal Divide
135
Cannot cross this divide by fractional crystallization; cannot derive one series from the other (at least via low-P fractional crystallization)
Thermal Divide
136
when plagioclase is a fractionating phenocryst or a residual solid in source
Europium Anomaly
137
a non-destructive analytical technique used to determine the elemental composition of materials.
XRF or X-ray Fluorescence
138
It determines the chemistry of a sample by measuring the secondary X-ray emitted form a sample when it is excited by a primary X-ray source
XRF or X-ray Fluorescence
139
Application of XRF
1. research in Igneous, Sedimentary and Metamorphic Petrology
2. Mining (measuring the grade of ore)
3. Cement Production
4. Ceramic and Glass Manufacturing
5. Metallurgy (Quality Control)
6. Environmental Studies (Analyses of particulate matter on air filters)
7. Petroleum Industry (Sulfur Content of Crude Oils and Petroleum Products)
8. Field Analysis in geological and environmental Studies (using portable, handheld XRF spectometers)
140
XRF is particularly well suited for investigations that involve
1. Bulk chemical analyses of major elements (Si, Ti, Al, Fe, Mn, Mg, Ca, Na, K, P) in rock and sediment
2. Bulk chemical analyses of trace elements (in abundance > 1 ppm ; Ba, Ce, Co, Cr, Ga, La, Ni, Rb, Sc, Sr, Rh, U, V, Y, Zr, Zn) in rock and sediment - detection limits for trace elements are typically on the order of a few parts per million
141
XRF is limited to analysis of
1. relatively large samples, typically >1
2. materials that can be prepared in powder form and effectively homogenized
3. materials for which compositionally similar, well-characterized standards are available
4. materials containing high abundances of elements for which absorption and fluorescence effects are reasonably well understood
142
the primary, non destructive tool for identifying and quantifying the mineralogy of crystalline compounds in rocks, soils and particulates
XRD or X-ray Diffraction
143
Every mineral or compound has a characteristic _______________ pattern whose fingerprint can be matched against a database of over 250,000 recorded phases
XRD or X-ray Diffraction
144
________________ can interpret the diffraction traces produced by individual constituents and highly complex mixtures
Modern Computer- Controlled diffraction Systems
145
An essential technique for identifying and characterizing the nature of clay minerals, providing information which cannot be determined by any other method
XRD or X-ray Diffraction
146
Application of XRD
1. characterization of lithologies intended for radioactive waste disposal and carbon dioxide capture/storage
2. researching changes in soil clay mineralogy with different land management practices
3. determining the contribution of clay minerals to the engineering behavior of rocks and soils
4. distinguishing natural and anthropogenic sources of toxic elements in brown field sites
5. providing forensic evidence
6. providing indicators of geological history, basin maturity and low grade metamorphism
147
A spectroanalytical procedure for the quantitative determination of chemical elements using the absorption of optical radiation (light) by free atoms in the gaseous state
AAS or Atomic Absorption Spectroscopy
148
In analytical chemistry it is used for determining the concentration of a particular element (the analyte) in a sample to be analyzed
AAS or Atomic Absorption Spectroscopy
149
Used to determine over 70 different elements in solution or directly in solid samples
AAS or Atomic Absorption Spectroscopy
150
An analytical technique used for elemental determinations
ICP - MS or Inductively Coupled Plasma Mass Spectrometry
151
It is accomplished by counting the number ions at a certain mass of the elements
ICP - MS or Inductively Coupled Plasma Mass Spectrometry
152
most samples analyzed by ICP-MS are ___________
Liquid
153
Solid samples for ICP-MS must be ___________ before measuring
Liquefied
154
Gas samples In ICP-MS can be ____________
measured directly
