What are Geology
and Geophysics?
What is Geology?
Geology is the study of the Earth. It includes
composition and material, structure, processes, and history. Geology encompasses several
special areas of study, including at least the following.
Geochemistry is the study of the
distribution of chemicals in the Earth and atmosphere. Geomorphology is the
study of landforms and underlying structures. Historical Geology is the
study of the Earth’s evolution. Paleobotany is the study of plant life
in the geologic past. Paleogeography is the study of Physical Geology in
the geologic past. Paleontology is the study of past life observed in the
geologic record (fossils). Physical Geology is the study of processes,
materials and morphology of the Earth. Sedimentology is the study of
sediment deposition. Stratigraphy is the study of relationships of rock
strata. Structural Geology is the study of geologic structures such as
faults and folds. Tectonics deals with large scale Earth structures such as
tectonic plates and its deep interior. Volcanology is the study of
volcanoes and volcanic processes.
What is Geophysics?
Geophysics is the study of the Earth by
quantitative physical methods. It is an applied science and includes the Earth’s
interior, crust, oceans, atmosphere and magnetosphere. Applications are broad and can
include magnetic studies related to the Earth’s interaction with the Sun; plate
tectonics and the interior of the Earth; petroleum and mineral exploration; environmental
and engineering analyses; and even archaeological investigations. Special areas of study
include the following, among others.
Seismology is the study of seismic data.
There are generally three catagories of seismic data. Reflection seismic data is
most commonly used for petroleum exploration because of its resolution and level of
detail. Refraction seismic data is used mostly to define major layer boundaries
within the Earth. Earthquake seismic data is used to study the Earth’s deep
internal structure.
Potential Fields studies involve work with
the Earth’s gravity, magnetic and electric fields. Traditionally gravity and
magnetic data have been used in early stages of petroleum exploration. Magnetics is used
extensively for mineral exploration as well. Although there are some applications for
electrical methods in petroleum exploration, they are mostly tools for mineral
exploration, as well as environmental analyses. Micro-gravity measurements are used in
engineering analyses.
For an explanation of my background image, which
shows elements of both gravity and magnetic data, go to Background
Image. For a discussion and my point of view about specific concepts with
regard to gravity and magnetic data interpretation go to Issues.
Remote Sensing methods utilize data
collected by radar systems, cameras, infrared sensors and microwave receivers. Imagery
derived from airborne and satellite data are used to identify major surface or
near-surface structures and areas of varying composition including vegetation, rock types,
heat flow etc. Typically aircraft or satellites collect the data. Ground penetrating
radar (GPR), collected in relatively smaller areas on land, is a radar system that is
frequently used to interpret near surface areas, particularly for environmental,
engineering or archaeological applications.
