Geology a science built on the foundations of other sciences

Mathematics is defined as "the study of numbers, their form, arrangement, and associated relationships, using rigorously defined literal, numerical, and operational symbols."  From The American Heritage dictionary

Andrew Vistelius noted in the introductory issue of Mathemat­ical Geology in 1969 that the "inductive thinking of geologists" and the "deductive one of a mathematician" combined "would discover more differences than likeness" and spoke about an interaction that would bring about a "science that is neither geology nor mathematics".  Mathematics in geology has been used to help us quantify geological problems. For example the extrapolation of the age of the earth was determined by understanding the ratio of decay of uranium to lead.

Pythagoras lived from 570-500 B.C. and was reported to have said "all things are numbers".  The idea is to see things visually, but until they have been converted into some kind of numerical model it is difficult to understand them.

Mathematics also teaches us to think quantitatively.  Many of the early theories in geology were based on large sweeping generalizations. Until theories can be proven (or unproven) in a scientific and quantitative method, it is difficult to verify or validate them. Computer modeling can't be done without mathematics.  Statistics and predictive modeling is needed in what studying geomorphology and landforms.

Another example of the use of mathematics in geology was given by H.L. Vacher Department of Geology from the University of South Florida in referring to strike and dip problems "Solving the problem computationally rather than graphically gives experience in applying mathematics to a problem that very definitely comes up in the real world." Without translating strike and dip into quantitative numbers mathematical modeling becomes impossible.  (Strike is the direction along which a structural surface can be traced and dip the angle at which the plane of that structure follows) There are many other examples especially in the mining industry where without math, analyzing and predicting ore deposits and the location of these, would be very difficult.

Biology

Modern gastropod

Biology addresses organic life.  We also think of it as dealing with living organisms.  Organisms found as fossils are records of ancient life. Charles Lyell in the early 1800's "stated that the study of living shells was essential to the development of the understanding of paleontology."  (Paleo meaning ancient, and ontology or the study of being, put together means the study of life as it was.)

Originally the word fossil meant any object that had been dug up.  Today fossils are classified as the remains or traces of organic life. We use biology to provide knowledge about what the organism was and if it was an animal, how it may have moved when it was alive.  Unfortunately not all of the geological record is very good in preserving ancient life forms.  The reason for this is that the organism must have had sufficient body structure for it with stand burial and to be recorded as a fossil.  The paleo-environment in which the organism lived in had to be to be of sufficient low energy so as not to break up or destroy the remains or traces of the organism. Finally even the grain size of the material which encased or preserved the organism, had to be small enough to be able to create an appropriate mold (e.g.  Gravel would not be a good medium for preserving fossils). 

This generally restricts fossils to sedimentary environments and is the reason why the majority of the fossils are found in limestone and shale (these both have lower energy environment during deposition and have finer grains than other sedimentary environments). In some very rare cases fossils have been found in volcanic rock.  Metamorphic rocks involve too much pressure and heat (providing that it is fossilized sedimentary rock undergoing metamorphism in the first place) and at best, the fossil will be highly deformed or broken up.

The expression, "the present is the key to the past" would imply that by understanding living organisms we can understand those that have died. Yet the fossil record shows significant differences in the species that lived in the past from those that live today.  In addition periods of extinction have killed off large numbers of species that lived in the past and that are no longer alive today.

Accepting Darwin's theory of evolution, we know that organisms mutate or change over time.  Therefore we need to understand the biology of the planet today in order to extrapolate what the biology of the planet was or might have been during the time that the organisms were buried. By classifying and dating ancient life forms in the geological record we can establish an index to help us date the age the rocks in which the fossils are buried. By understanding the conditions in which modern organism live, it helps us understand the Paleo environment during the time the rocks were deposited.

Nikolai Steno, a 16th century anatomist who studied body structures, was notably one of the first to recognize fossilized sea-based life for what it was. He hypothesized that the oceans at one point had covered the land and even went so far as to suggest that the land had been uplifted after it had been covered. Furthermore Steno developed some of the first geological "laws" as a result, including the law of superposition, horizontally and lateral continuity. (It should be noted that this was a remarkable hypothesis considering the religious atmosphere of the 1600's which believed that the earth had been created in seven 24-hour days.  The explanation for fossils at the time was that they were replicas of living creatures placed there at the same time all living creatures were created. Later shells found on the top of mountains were attributed to the diluvian floods from the time of Noah rather than having been subaqueous land that had been uplifted.)

Biology, and specifically taxonomy, provides a method of classifying plants and animals.  William Smith (considered one of the founding fathers of Geology) was able to use this classification system to correlate the stratigraphy of rocks found in different locations.  This early method helped to tie together rocks that were in different localities.  Rocks or strata that was different in composition but that had the same fossils - were considered to have been deposited at the same time. Great care was needed to ensure correct identification of the fossils as tiny differences could introduce significant error in analysis.   Others living prior to Darwin's theory of evolution, such as the French geologist Cuvier, the Swiss and later naturalized American Louis Agassiz, used this information in the development of their theories - however there was great controversy over the reason for biological differences and more specifically whether these organisms were evolved or trans-mutated. 

Biology in geology is not just used in paleontology. Biological processes also contribute to erosion.  Plant roots may even secrete chemicals to allow them to extract minerals which can break down rocks.  More commonly tree roots are seeing as breaking up soils, displacing rocks and even splitting boulders. Soil development involving organic composting occurs as the result of biological processes. Even earthworms move tons of soil; change the morphology of the land form.

Geology also helps biologists.  It provides a record over time of what the organisms looked like when it lived in the past.  As such, it provides an evolutionary trail of life-from single celled organisms to the complex life forms of today. The oldest fossils of simple organism date back to almost 3.8 billion years ago.  However more complex life did not start occurring until only 350 to 500 million years ago. As such complex life is a relatively new geological occurrence - having been around for only about 1/10^th of the world's history.

Fossil Gastropod

Physics

Physics helps to explain folding

The Big Bang.  The primeval fireball.  "The Big Bang Model is a broadly accepted theory for the origin and evolution of our universe. It postulates that 12 to 14 billion years ago, the portion of the universe we can see today was only a few millimeters across. It has since expanded from this hot dense state into the vast and much cooler cosmos we currently inhabit. We can see remnants of this hot dense matter as the now very cold cosmic microwave background radiation which still pervades the universe and is visible to microwave detectors as a uniform glow across the entire sky." From NASA http://map.gsfc.nasa.gov/universe/bb_theory.html

How does this affect geology? What does physics have to do with this?  The theory is that it would require such an explosion to form the elements, and this formation of the elements requires an understanding of physics.  But the formation of the universe and the earth's place in the universe is better studied under the branch of science known as cosmology.  (Not to be confused with cosmogony that invokes mythical and supernatural forces in the creation of the earth and which was pivotal in the early debates about geology.)

While physics plays an important role in understanding the creation of the earth, physics plays an even greater role in understanding the physical processes that take place on our planet.

The study of Geology demands physics.  Geological formations are the result of what happens when matter and energy interact. Geological events require significant force and energy. The earth is in constant motion, spinning around the sun and revolving on its own axis.  Huge plates make up the crust of the earth and are constantly being extruded and subducted underneath continents. Mountains are being uplifted. Solid rock moves, the earth quakes, and ice, oceans, rain, and rivers are constantly wearing down the surface of the land.  A molten interior causes a magnetic field which effects the orientation of the rocks magnetic field.  Pressure from miles of buried rock causes it to become plastic and malleable.  Gravity pulls at the top of the mountains to constantly erode the rocks. High-density meteorites or bolides crash into the earth at extreme speeds causing massive deformation of the crust.  Their impact and earthquakes cause tsunamis. Wind causes waves.  And continents float.

 All of these forces and actions are governed by physical forces.  All of these forces interact with the follow the laws of physics.  The stability of a slope, for example, is determined by a relationship between the stress causing the materials to move and the materials ability to resist those stresses.  This ratio is often known as a safety factor, and can be quantified by comparing information about the sheer plane, the total amount of sheer stress, the weight of the mass or regolith, and its cohesiveness, all governed by physical laws.  Another example of physical laws is how particles are transported by fluids or in rivers. This is affected by such physical laws involving lift components, fluid force, gravity and entrainment (the process of picking up sediments or grains).

Geophysics is a branch of Geology that studies the Earth using quantitative physical methods.  While we tend to think of geophysics as primarily trying to understand seismology or the movement of Earth, there are plenty of smaller practical applications for physics.  Physics is also involved when ice freezes and thaws and move stones upward through the soil.  Mechanical forces involved in breaking down and transporting rocks follow physical laws. 

So whether geologists are trying to understand the creation of the universe, plate tectonics, mountain building, U-shaped glacial valleys, or how streams carved Grand Canyon, physics is involved.

Chemistry

Carlsbad Caverns

Go down into a cave.  Pick up a handful of crumbled granite.  Feel the dried salt on your body after a visit to the beach. Chemical processes are changing the world all around you.

Chemistry is the science that studies the makeup, composition, and the characteristics or traits of molecular or atoms -including the reactions between different molecules or atoms.  You can see the basic building blocks of all geology by looking at a periodic chart of the elements.  (A periodic chart is a listing of the basic elements and defines their weight in atomic numbers showing the number of protons in an atomic nucleus and was originally created by Dmitri Ivanovich Mendeleev (1834-1907)).  The elements are themselves minerals or form minerals.  And the unique properties of these elements and minerals give rise to crystals and rocks.

Both organic and inorganic chemistry is involved in Geology as all rocks, soils and dirt are made up of these elements and minerals. Whether the minerals are solidified in a massive rock formation, as part of the ocean floor, or whether they've been broken down to microscopic elements and mixed with organic matters to form soil, they all have a specific chemical makeup.  Chemistry not only studies their makeup, but it also tries to understand how different minerals and elements react with each other.  That reaction can cause a mineral to be dissolved and reformed or precipitated in another form.  In some cases, such as the formation of dolomite, it is thought that specific elements (specifically calcite) are replaced with other elements (specifically magnesium).  Chemical reactions are involved in erosion as well as in the deposition and formation of sedimentary rocks.

Chemistry is also needed to understand how rocks and minerals behave. Chemistry controls the crystalline structure, the temperature at which the rock melts, and even how the rock reacts and forms under stress and pressure.

The branch of Geology known as geochemistry "is the study of the distribution and amounts of the chemical elements and minerals, ores, rocks, soils, water, and the atmosphere, and the study of circulation of the elements in nature, on the basis of the properties of their atoms and ions" (glossary of Geology.)  Victor Moritz Goldschmidt (1888 -- 1947) is considered the father of modern geochemistry and Crystal chemistry.  There is even a Geochemical Society that focuses strictly on the application of chemistry in Geology.

Heat which is a form of energy helps to increase chemical activity.  As such geothermal activity, that is heat which comes from the interior of the earth, as a profound impact on chemical reactions.

Geothermal features such as those found in the Yellowstone National Park is a laboratory for chemists.  Boiling waters bring minerals to the surface, depositing them in all sorts of different formations.  These formations are also found were underwater volcanic activity has brought minerals through steam vents to the surface.

Erosion of limestone

In summary

Aristotle proposes that were four elements, Earth, fire, air and water.  Aristotle believed that out of these elements one can create all of the inorganic and organic things of this world.  (While today the periodic table lists 103 elements, those elements 93 and above do not occur naturally.)  Geology likewise has its own elements that make up the science.  We use mathematics for quantifying geology and computing.  Chemistry helps us to understand the makeup of minerals and rocks as well as the actions and reactions between them. Biology helps us to identify organisms that lived in the past as well as correlates rock formations and stratigraphy.  Finally it is the study of physics, which allow us to understand how rock formations are uplifted, eroded and, folded and melted.