A geologist is a scientist who studies the solid and liquid matter
that constitutes the
Earth as well as the processes that shape it.
Geologists usually study geology, although backgrounds in physics,
chemistry, biology, and other sciences are also useful.
Field work is
an important component of geology, although many subdisciplines
incorporate laboratory work.
Geologists work in the energy and mining sectors searching for natural
resources such as petroleum, natural gas, and precious metals. They
are also in the forefront of preventing and mitigating damage from
natural hazards and disasters such as earthquakes, volcanoes, tsunamis
and landslides. Their studies are used to warn the general public of
the occurrence of these events. Geologists are also important
contributors to climate change discussions.
2 Training / Schooling
2.1 Areas of specialization
4 Professional designation
5 See also
Scotsman James Hutton, father of modern geology
James Hutton is often viewed as the first modern geologist. In 1785
he presented a paper entitled Theory of the
Earth to the Royal Society
of Edinburgh. In his paper, he explained his theory that the Earth
must be much older than had previously been supposed in order to allow
enough time for mountains to be eroded and for sediments to form new
rocks at the bottom of the sea, which in turn were raised up to become
dry land. Hutton published a two-volume version of his ideas in 1795
(Vol. 1, Vol. 2). Followers of Hutton were known as Plutonists because
they believed that some rocks were formed by vulcanism, which is the
deposition of lava from volcanoes, as opposed to the Neptunists, led
by Abraham Werner, who believed that all rocks had settled out of a
large ocean whose level gradually dropped over time.
"Geologists at work" from the U.S. Geological and Geographic Survey of
the Territories. (1874 - 06/30/1879) Photographer: William Henry
The first geological map of the U.S. was produced in 1809 by William
Maclure. In 1807, Maclure commenced the self-imposed task of
making a geological survey of the United States. Almost every state in
the Union was traversed and mapped by him; the Allegheny Mountains
being crossed and recrossed some 50 times. The results of his
unaided labours were submitted to the American Philosophical Society
in a memoir entitled Observations on the
Geology of the United States
explanatory of a Geological Map, and published in the Society's
Transactions, together with the nation's first geological map. This
antedates William Smith's geological map of England by six years,
although it was constructed using a different classification of rocks.
Sir Charles Lyell
Sir Charles Lyell first published his famous book, Principles of
Geology, in 1830. This book, which influenced the thought of
Charles Darwin, successfully promoted the doctrine of
uniformitarianism. This theory states that slow geological processes
have occurred throughout the Earth's history and are still occurring
today. In contrast, catastrophism is the theory that Earth's features
formed in single, catastrophic events and remained unchanged
thereafter. Though Hutton believed in uniformitarianism, the idea was
not widely accepted at the time.
Training / Schooling
A young geologist learns about flow banding
For an aspiring geologist, training typically includes significant
coursework in physics, mathematics, and chemistry, in addition to
classes offered through the geology department; historical and
physical geology, igneous and metamorphic petrology and petrography,
hydrogeology, sedimentology, stratigraphy, mineralogy, palaeontology,
physical geography and structural geology are among the many required
areas of study. Most geologists also need skills in GIS and other
Geology students often spend portions of the year,
especially the summer though sometimes during a January term, living
and working under field conditions with faculty members (often
referred to as "field camp"). Many non-geologists often take geology
courses or have expertise in geology that they find valuable to their
fields; this is common in the fields of geography, engineering,
chemistry, urban planning, environmental studies, among others.
Areas of specialization
A geologist working in the Arctic
Jurassic sedimentary rocks in Makhtesh Gadol,
Negev Desert, Israel
Geologist explaining the importance of volcanic ash layers to students
on field in Iceland
Geologists may concentrate their studies or research in one or more of
the following disciplines:
Economic geology: the study of ore genesis, and the mechanisms of ore
Engineering geology: application of the geologic sciences to
engineering practice for the purpose of assuring that the geologic
factors affecting the location, design, construction, operation and
maintenance of engineering works are recognized and adequately
Geophysics: the applied branch deals with the application of physical
methods such as gravity, seismicity, electricity, magnetic properties
to study the earth.
Geochemistry: the applied branch deals with the study of the chemical
makeup and behaviour of rocks, and the study of the behaviour of their
Geochronology: the study of isotope geology specifically toward
determining the date within the past of rock formation, metamorphism,
mineralization and geological events (notably, meteorite impacts).
Geomorphology: the study of landforms and the processes that create
Hydrogeology: the study of the origin, occurrence and movement of
groundwater water in a subsurface geological system.
Igneous petrology: the study of igneous processes such as igneous
differentiation, fractional crystallization, intrusive and
Isotope geology: the case of the isotopic composition of rocks to
determine the processes of rock and planetary formation.
Metamorphic petrology: the study of the effects of metamorphism on
minerals and rocks.
Marine geology: the study of the seafloor; involves geophysical,
geochemical, sedimentological and paleontological investigations of
the ocean floor and coastal margins.
Marine geology has strong ties to
physical oceanography and plate tectonics.
Palaeoclimatology: the application of geological science to determine
the climatic conditions present in the Earth's atmosphere within the
Palaeontology: the classification and taxonomy of fossils within the
geological record and the construction of a palaeontological history
of the Earth.
Pedology: the study of soil, soil formation, and regolith formation.
Petroleum geology: the study of sedimentary basins applied to the
search for hydrocarbons (oil exploration).
Planetary geology: the study of geology as it relates to other
celestial bodies, namely planets and their moons. This includes the
subdiscipline of lunar geology, selenology, and martian geology,
Sedimentology: the study of sedimentary rocks, strata, formations,
eustasy and the processes of modern-day sedimentary and erosive
Seismology: The study of earthquakes.
Structural geology: the study of folds, faults, foliation and rock
microstructure to determine the deformational history of rocks and
Volcanology: the study of volcanoes, their eruptions, lavas, magma
processes and hazards.
"Picturesque camp made by a lone geologist on the cinders of Inferno".
This photo was taken during a U.S. Department of the Interior
Geological Survey in 1921
Professional geologists work for a wide range of government agencies,
private firms, and non-profit and academic institutions. They are
usually hired on a contract basis or hold permanent positions within
private firms or official agencies (such as the USGS).
Local, state, and national governments hire geologists to work on
geological projects that are of interest to the public community. The
investigation of a country's natural resources is often a key role
when working for government institutions; the work of the geologist in
this field can be made publicly available to help the community make
more informed decisions related to the exploitation of resources,
management of the environment and the safety of critical
infrastructure - all of which is expected to bring greater wellbeing
to the country. This 'wellbeing' is often in the form of greater
tax revenues from new or extended mining projects or through better
infrastructure and/or natural disaster planning.
Geologist mud logging, common in petroleum and water-well drilling
An engineering geologist is employed to investigate geologic hazards
and geologic constraints for the planning, design and construction of
public and private engineering projects, forensic and post-mortem
studies, and environmental impact analysis. Exploration geologists use
all aspects of geology and geophysics to locate and study natural
resources. In many countries or US states without specialized
environmental remediation licensure programs, such as Rhode Island and
North Carolina, the environmental remediation field is often dominated
by professional geologists, particularly hydrogeologists, with
professional concentrations in this aspect of the field.
mining companies use mudloggers and large-scale land developers use
the skills of geologists and engineering geologists to help them
locate oil and minerals, adapt to local features such as karst
topography or earthquake risk, and comply with environmental
Geologists in academia usually hold an advanced degree in a
specialized area within their geological discipline and are employed
The rock hammer and hand lens (or loupe) are two of the most
characteristic tools carried by geologists in the field.
National Instrument 43-101 requires reports containing
estimates of mineral resources and reserves to be prepared by, or
under the supervision of, a Qualified Person (QP) who has at least
five years of experience with the reported minerals and is a member of
a professional association. The QP accepts personal liability for the
professional quality of the report and underlying work.
The rules and guidelines codified in
National Instrument 43-101 were
introduced after a scandal in 1997 where
Bre-X geologists salted drill
core samples at a gold exploration property in Busang, Indonesia. The
falsified drilling results misled
Bre-X investors and upon discovery
of the fraud, the company collapsed in the largest gold mining scam in
List of geologists
^ James Hutton: The Founder of Modern
Geology Archived March 3, 2016,
at the Wayback Machine., American Museum of Natural History
William Maclure (1817). Observations on the
Geology of the United
States of America: With Some Remarks on the Effect Produced on the
Nature and Fertility of Soils, by the Decomposition of the Different
Classes of Rocks; and an Application to the Fertility of Every State
in the Union, in Reference to the Accompanying Geological
^ "Title Page: Observations on the geology of the United States of
^ Page 39 in Greene, J.C. and Burke, J.G. (1978) The Science of
Minerals in the Age of Jefferson. Transactions of the American
Philosophical Society, New Series, Vol. 68, No. 4, pp. 1-113
Map of the United States of America". davidrumsey.com.
^ Charles Lyell. (1991). Principles of geology. Chicago: University of
Chicago Press. ISBN 978-0-226-49797-6.
^ Geoscience Australia, Our Role, December 16, 2010,
http://www.ga.gov.au/about-us/our-role.html, Accessed: May 12, 2011
^ "AIPG - American Institute of Professional Geologists".
^ Grundhauser, Eric (21 August 2015). "The $6 Billion Gold Mine That
Wasn't There". Slate. Retrieved 21 September 2015.