APPLICATION OF
ISOTOPE GEOCHEMISTRY IN GEOSCIENCE
Isotopes do not fractionate during partial melting
or fractional crystallization processes. So they will reflect the
characteristics of the mantle source. Isotope geochemistry is an aspect of
geology based upon study of the natural variations in the relative abundances
of isotopes of various elements. While stable isotope geochemistry, is
concerned with variation of the isotropic compositions of light elements
arising from chemical fractionations rather than nuclear processes.
Isotope geochemistry; low
temperature application:
The isotropic composition of a
given element in living tissue depends on the source of that element like
atmospheric CO2 versus dissolved CO2, seawater O2
versus meteoric water O2. The isotropic composition of fossil
material will depend on any isotropic changes associated with diagenesis,
included microbial decomposition. In this point, how this way is inverted to
provide insights into the food sources of fossil organisms including man will
be show. Low temperature application shows that isotope ratios of carbon and
nitrogen are fractionated during primary production of organic matter. This
application showed that the relationship between the isotropic geochemistry
related to the geoscience or geology. Where is the application used into the rocks
to find the fossil.
Isotope geochemistry; high
temperature application:
Stable isotopes have a number of
uses in high temperature geochemistry such as igneous and metamorphic
geochemistry. This application used of the temperature dependency of
fractionation factors. The translational and rotation contributions to the
partition function do not vary with temperature. Then, one of the principles
used of stable isotopes is as geothermometers. Like conventional chemical
geothermometers, stable isotope geothemometers are based on temperature
dependence of the equilibrium constant. For example, calculated oxygen isotope
fractionation for several mineral pairs as a function of temperature. So, this
application is much related to the geoscience.
Application of isotope geochemistry
of natural gases and carbon:
There are two fundamental of
isotopes, stable and unstable (radioactive) species. Stable isotopes were not
subject to radioactive decay, which is their abundance in nature is controlled
by biological and physical processes like equilibrium reactions in the case of
the stable isotopes of carbon (12C and 13C). Meanwhile,
unstable isotopes experience to radioactive decay. It known as the half-life
and these isotopes used in age dating, for example, 14C. Carbon that
occurred in wide variety of compounds, from highly oxidized inorganic materials
like CO2 and sedimentary carbonate rocks to highly reduce organic
substances in the biosphere. Isotope equilibrium exchange reactions in the
inorganic carbon system (atmospheric CO2- dissolved
bicarbonate-solid carbonate) lead to an enrichment of 13C in
carbonate rocks. In the other hand, kinetic isotope effects during
photosynthesis concentrate 12C in organic matter. For distinguishing
natural gases from different sources, stable isotope geochemistry was provided
a powerful method.
Application of isotope geochemistry
to igneous petrogenesis:
One of the most fundamental
applications of isotopes to igneous systems is to use radiogenic isotopes as
“clocks” to date the crystallization ages of rocks. Isotropic compositions of
igneous rocks provided a wealth of information about the processes and
timescales involved in their formation. Numerous isotope systems, individually
combined, have provided a detailed understanding of a range of igneous processes
from the formation and early evolution of earth’s interior to ongoing
processes. The application to some of the most fundamentally important
processes in igneous petrology, included constrain on the timing of crust
mantle differentiation, timescales of magma formation and ascent, and the
processes and timescales of magma evolution. Crystallization ages of meteorites
and the oldest terrestrial minerals constrain the age of the earth and
formation evolution of ancient continental crust. Knowledge of the crystallization
ages of young volcanic rocks is necessary to determine of eruption recurrence
intervals. Radiogenic, stable and cosmogenic isotope systems also play
fundamental roles as tracers of diverse igneous processes.
Application of isotope geochemistry
in petroleum geoscience:
Petroleum system is a natural
system that encompasses a pod of petroleum source rocks and all related oil and
gas which included all the geologic elements and processes that are essential
if a hydrocarbon accumulation is to exist. Essential elements of a petroleum
such as a petroleum source rock, a petroleum reservoir rock, a seal rock and an
overburden rock. Meanwhile, essential processes of petroleum such as trap
formation and generation migration accumulation of petroleum. Modern isotope
and biomarker analyses on the molecular level readily allow the identification
and separation of multiple sources of oils in a petroleum system, where oils
were inherit the molecular and isotropic character of the parent oil. Stable
isotope applications in liquids; to correlation of whole oils, bitumens and
kerogen, and quantitative estimates of oil co-sources.
Discussion
Overall in this
application used in the geoscience. Firstly, isotropic composition of fossil material
will depend on any isotropic changes associated with diagenesis to provide
insights into the food sources of fossil organisms. There are several reasons
for the controversy, but all ultimately relate to the extremely complex
geological history of the area. Then, high
temperature geochemistry such as igneous and metamorphic geochemistry, which is
his application used of the temperature dependency of fractionation factors.
The nature of chemical bond is of primary importance in determining isotope
fractionations. For example, comparison of quartz-mineral fractionation factors
estimated from the difference in oxygen site potential and experimentally
observed fractionation.
Next, carbon
that occurred in wide variety of compounds, from highly oxidized inorganic
materials like CO2 and sedimentary carbonate rocks to highly reduce organic
substances in the biosphere. Sedimentary carbonates and organic matter possess
distinct stable carbon isotope compositions because of the operation of two
different reaction mechanisms. Applications of
isotopes to igneous systems used radiogenic isotopes as “clocks” to date the
crystallization ages of rocks. Thus, provides a critical link to volcanic
hazard assessment and eruption forecasting. For petroleum geoscience, where it
related to the exploration, development, production and field abandonment of
petroleum.
This will
provide a general overview of first principals concerning stable isotope
geochemistry in the earth sciences.
