geochemistry

Geochemistry refers to the science that uses chemistry tools and principles to explain the mechanisms behind main geological systems like the crust of the earth and its oceans. It combines chemistry and geosciences.

LEARNING OBJECTIVES

By the end of this topic, you are expected to;

• Understand the meaning of geochemistry
• Understand the importance of geochemistry
• Understand the work of geochemists
• Understand geochemical cycles
• Understand the different subfields of geochemistry

Geochemistry applies chemical principles and chemistry to understand the Earth and its environment and use the understanding to better lives. Geochemistry extends beyond the earth and covers the entire solar system. Geochemistry has lead to the understanding of different processes such as the origins of basalt and granite, the formation of planets, and mantle convection. It plays a major role in helping us understand important environmental problems like soil and water pollution, ozone layer depletion, and global warming.

A geochemist is a person who studies the interaction of chemicals with the natural world. They apply knowledge from both geology and chemistry. Geologists study naturally occurring elements then make informed decisions. For example, geologists can study certain rocks and tell that oil is nearby. Geochemists perform different duties depending on their field. For example, planning studies, field visits, and collecting samples. They also analyze these samples in the field or in a lab. Geochemists help to guide gas and oil exploration using petrographic services, geological data, and aerial photographs. Geologists in other fields can predict the frequency and occurrence of earthquakes.

GEOCHEMICAL CYCLES

The geochemical cycle refers to the pathway taken by chemical elements in the crust and surface of the earth. In this cycle, both chemical and geological factors are included. The migration of compressed and heated chemical compounds and elements like aluminum, silicon, and general alkali metals by means of volcanism and subduction is geochemical cycles. This cycle encompasses the natural concentration and separation of elements and recombination processes assisted by heat.

It is important to note that geochemical cycles are different from biogeochemical cycles. While the biogeochemical cycle refers to the interactions in surface reservoirs such as the hydrosphere, atmosphere, biosphere, and lithosphere, the geochemical cycle refers to the interactions in crustal reservoirs like lithosphere and deep earth.

The three major geochemical cycles that exist on the earth are:

• hydrologic cycle, deal with the movement of water around the earth's surface, both underneath and on the surface of the earth
• rock cycle, deal with rocks
• tectonic cycle, deal with the rock deformation process.

 

SUBFIELDS

Some of the subfields of geochemistry include;

• Aqueous geochemistry. It studies the role of different elements in watersheds, including mercury, copper, sulfur, and how elemental fluxes are exchanged through atmospheric-terrestrial-aquatic interactions.
• Regional geochemistry. This includes applications to mineral explorations, environmental and hydrological studies.
• Photogeochemistry. This is the study of chemical reactions that are light-induced that may occur among natural components of the surface of the earth.
• Organic geochemistry. This studies the role of compounds and processes derived from living organisms or those that once lived.
• Isotope geochemistry. This involves the determination of the absolute and relative concentrations of elements as well as their isotopes on the surface of the earth and in the earth.
• Cosmochemistry. This includes the analysis of element distribution and their isotopes in the cosmos.
• Biogeochemistry. This is a field of study that focuses on the effect of life on the earth’s chemistry.

GEOLOGICAL MAJOR ELEMENTS

These are elements that make up 95 percent of the crust of the earth. They are Si, Al, Ca, Mg, Na, K, Ti, Fe, Mn, and P.