Geochemistry Flashcards
Comprises the minimum number of chemicals, both atomic and molecular, species required to specify completely the compositions of all the phases present.
Component
An invariant point point in the phase diagram where the maximum number of allowable phases intersect and are in equilibrium. It could also be a point where Solidus and liquidus intersect.
Eutectic point
State of equilibrium with 0 degrees of freedom.
Invariant Equilibrium
An invariant point in a phase diagram where two faces that could never co-exist together react with each other to produce a new phase.
Peritectic Point
Enumerate the Light Rare Earth Elements
Mnemonics: Loyal Champions Protect Noble Princes, Seeking Emeralds
Lanthanum, Cerium, Praseodymium, NEODYMIUM, Promethium, Samarium, EUROPIUM
Enumerate the Heavy Rare Earth Elements
Mnemonics - Young Giants Tame Dragons, Holding Every Treasure You Love
YTTRIUM, Gadolinium, TERBIUM, DYSPROSIUM, Holmium, Erbium, Thulium, Ytterbium, Lutetium
Describe Sb/Sr magma signature.
Geochem signature of magma assimilation process. If melt has high Rb (incompatible element for melts) it will produce more Sr.
Describe Sm/Nd magma signature.
Geochem signature of magma assimilation process. Sm is more compatible with the melt during partial melting compared to Nd
Describe the Mg# and Fo# magma signature.
relationship of olivine and coexisting basaltic melt by studying Mg and Fe Content.
Describe Cr# magma signature.
The geochem signature of mantle derived magma. Fertile unaltered mantle originates as Lherzolite. Lherzolite evolves into tholeiitic basalt, leaving Dunite and Harzburgite as refractory residuum enriched with Cr.
Describe the trend of TiO2, FeO, MgO, CaO, P2O5, K2O, Na2O, and Al2O3 with increasing silica.
a. Decrease in TiO2, FeO, MgO, CaO, P2O5
b. Increase in K2O, Na2O
c. No strong variation in Al2O3
Determines the elements present in a material by measuring the secondary x-ray emitted by a sample when it is agitated by a primary x-ray source.
X-Ray Fluorescence
• Fluorescent (Secondary x-ray)
Quantifying present compounds in minerals, rocks, soils and particulates by detecting signature x-ray diffraction pattern.
X-Ray Diffraction
Quantitative determination of elements present in a material by using their absorption of optical radiation (light) by free atoms in the gaseous state.
Atomic Absorption Spectroscopy
Determining elements present in a material by quantifying the number of ions at a certain mass of the element.
Inductively Coupled Plasma Mass Spectrometry (ICP-MS)
Analytical technique that determines elemental mercury content.
Direct Mercury Analyzer (DMA-80)
Analytical technique that provides detailed information on chemical structure, phase and polymorphy, crystallinity and molecular interactions of a sample based on how light interacts with the chemical bonds.
Raman Spectroscopy
Enumerate the Platinum Group Elements
Platinum (Pt), palladium (Pd), rhodium (Rh), ruthenium (Ru), osmium (Os) and iridium (Ir)
Siderophiles that are mostly used to study melting and crystallization in mafic-ultramafic systems where these said elements are typically hosted by sulfides
a. REE
b. Sc
c. PGEs
d. Sr
Platinum Group Elements
Indicates pyroxene fractionalization as it is concentrated in pyroxenes.
a. REE
b. Sc
c. PGEs
d. Sr
Scandium
A compatible element/elements in low P and may substitute for Ca in plagioclases and K in K-felds.
a. REE
b. Sc
c. PGEs
d. Sr
Strontium
Indicates source characteristics and liquid evolution.
a. REE
b. Sc
c. PGEs
d. Sr
REEs
Commonly incompatible and strongly partitioned into garnet and amphiboles.
a. Y
b. Ni, Co, Cr
c. Zr, Hf
d. Nb, Ta
Yttrium
High compatibility where high concentrations show an indication of a mantle source, limited fractionation, or crystal accumulation.
a. Y
b. Ni, Co, Cr
c. Zr, Hf
d. Nb, Ta
Nickel, Cobalt, Chromium
High incompatibility where high concentrations implies an enriched source or extensive liquid evolution.
a. Y
b. Ni, Co, Cr
c. Zr, Hf
d. Nb, Ta
Zirconium and Hafnium
HFSE elements where low concentrations is an indication of subduction related melts environment and is commonly associated with Ti-rich phases such as Titanite and Ti-amphibole.
a. Y
b. Ni, Co, Cr
c. Zr, Hf
d. Nb, Ta
Niobium and Tantalum
The hottest Geothermal Resource type
Hot Rock
What type of Geothermal Enthalpy is the Philippines classified? What is the temperature range?
High Enthalpy (>150°C)
A nonthermal manifestation of hydrothermal/geothermal systems.
Kaipohan or “Cold springs”
Minerals that appear at temperatures greater than 200°C in Geothermal environments.
Epidote and Illite
Mineral geothermometer that appears at low temp and alkaline environments. What is its counterpart? (High T, acidic environment)
Calcite and Silica respectively
Mineral geothermometer that appears at low temperature and acidic environments where steam mixes with meteoric water due to throttling.
Kaolinite
The Father of Philippine Geothermal Development.
Arturo Alcaraz
What is the formula of the ratio of parent and daughter in a certain number of half-lives n?
1:(2^n)-1
1 HL = 1:1
2 HL = 1:3
3 HL = 1:7
What is the wavelength of Visible Light
750 nm - 400 nm
Wavelength Range of Infrared
25 μm - 2.5 μm
Wavelength Range of Gamma Rays
< 10^-12 m
Wavelength Range of X-ray
1 nm - 1 pm
Wavelength of Microwave
1 mm - 25 μm
Wavelength of radiowave
> 1 mm
It is named as the “shortest” and the “longest” days of the year
Winter Solstice - Shortest
Summer Solstice - Longest
The apparent twinkling of a star due to its light passing through regions of differing air densities in the atmosphere.
Scintillation
Stony meteorites composed primarily of silicate minerals.
Aerolite
A type of meteorite that contains both metal and silicate minerals also called stony-iron meteorites
Siderolite
For dating of rocks potassium-40 decays to argon-40 with a half-life of how many billions of years?
1.3
Rubidium- strontium method is used for which measurement in geology?
a. rock erosion
b. geologic time
c. deposition of sediments
d. lava flows
Geologic time
What is a key assumption required for Potassium-Argon (K-Ar) dating?
a. The rock must contain no carbon
b. No radiogenic argon was present when the rock formed
c. The rock must be older than 1 million years
d. The rock must have a high concentration of lead
No radiogenic argon was present when the rock formed
Which of the following dating methods is limited to materials less than 50,000 years old?
a. Uranium-Lead (U-Pb) Dating
b. Potassium-Argon (K-Ar) Dating
c. Radiocarbon (C-14) Dating
d. Luminescence Dating
Radiocarbon (C-14) Dating
What is a potential drawback of using Uranium-Lead (U-Pb) dating?
a. It requires the assumption of a closed system
b. It cannot be used on sedimentary rocks
c. It is only applicable to igneous rocks
d. It provides age estimates that are too young
It requires the assumption of a closed system
What assumption is critical for Luminescence Dating to be accurate?
a. The carbon-14 ratio has remained constant
b. The mineral grains were completely bleached prior to burial
c. The rock contains no argon
d. The uranium content is uniform throughout
The mineral grains were completely bleached prior to burial
Which dating method is noted for being sensitive to alteration and weathering?
a. Potassium-Argon (K-Ar) Dating
b. Luminescence Dating
c. Rubidium-Strontium (Rb-Sr) Dating
d. Radiocarbon (C-14) Dating
A, B, and C
Fission-track method is used for what purpose
dating of minerals
For what are isotopes of an element used in geology?
a. in analysis of minerals
b. in radioactive dating
c. in stratigraphic analysis
d. in classification of minerals
in radioactive dating
Varve analysis is done to calculate what?
a. age of glacial deposits
b. age of fossils
c. rate of deposition of sediments
d. number of lava flows
age of glacial deposits
Which mineral is known for containing significant amounts of Palladium?
a. Ilmenite
b. Chromite
c. Pentlandite
d. Sphalerite
Pentlandite
The Gibbs’ Phase Rule can be written as:
P=C+2-F
Explain why oxygen isotopes are important concerning Earth history.
O-18 is dense, making it more enriched in oceans while O-16 is lighter and is evaporated to be more enriched in higher elevations.
How can Oxygen Isotopes help determine glacial events?
Glaciers store huge volumes of O-16 enriched waters leaving oceans to reach maximum O-18 enrichment.
