What is Geology: Definition and 76 Discussions

Geology (from the Ancient Greek γῆ, gē ("earth") and -λoγία, -logia, ("study of", "discourse")) is an Earth science concerned with the solid Earth, the rocks of which it is composed, and the processes by which they change over time. Geology can also include the study of the solid features of any terrestrial planet or natural satellite such as Mars or the Moon. Modern geology significantly overlaps all other Earth sciences, including hydrology and the atmospheric sciences, and so is treated as one major aspect of integrated Earth system science and planetary science.

Geology describes the structure of the Earth on and beneath its surface, and the processes that have shaped that structure. It also provides tools to determine the relative and absolute ages of rocks found in a given location, and also to describe the histories of those rocks. By combining these tools, geologists are able to chronicle the geological history of the Earth as a whole, and also to demonstrate the age of the Earth. Geology provides the primary evidence for plate tectonics, the evolutionary history of life, and the Earth's past climates.
Geologists use a wide variety of methods to understand the Earth's structure and evolution, including field work, rock description, geophysical techniques, chemical analysis, physical experiments, and numerical modelling. In practical terms, geology is important for mineral and hydrocarbon exploration and exploitation, evaluating water resources, understanding of natural hazards, the remediation of environmental problems, and providing insights into past climate change. Geology is a major academic discipline, and it plays an important role in geotechnical engineering.

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  1. R

    In the contact zone between geology and physics...

    My name is Ron Werner, Dutchman, living/working in Norway since 1992. My main interest is geology and I have worked for several museums and mineral-dealers during my life. Since 2000 I have worked for the Evje og Hornnes geomuseum Fennefoss in Evje, in the south of Norway. It is a small museum...
  2. DaveE

    RIP Jason Morgan, pioneer of the theory of plate tectonics, the basis of modern geology

    RIP Jason Morgan, pioneer of the theory of plate tectonics, the basis of modern geology. https://www.princeton.edu/news/2023/08/14/w-jason-morgan-pioneer-plate-tectonics-dies-87
  3. getsrawal

    Wyllie time-average equation vs Gardner's equation vs RHG Equation for porosity

    If you were estimating porosity from velocity, which approach would you prefer to use among Wyllie time-average equation, Gardner's equation Or RHG Equation, when and why? My answer is RHG equation as wylllie equation don't work for unconsolidate sand and give accurate results when it is...
  4. S

    B Explaining Variations of Free-Fall Gravity on Earth?

    I stumbled upon gravitational variations that do not coincide with altitude, latitude or lunar interference. The only logical explanation I have for this would be the geology or makeup of the earth below those locations. But what is the variation of the Earths makeup below the crust? From my...
  5. Andy Resnick

    The Secrets of Prof. Verschure's Rosetta Stones

    (Edit: since the thread title was changed, this first sentence is too cryptic: the original title referred to a Tool song....) Besides being a favorite song by a favorite band, the thread title is a straightforward play on words. This summer, as a present to myself for being promoted, I...
  6. BillTre

    Cool Geology Pics - Share Yours Here!

    Here is one I found on Twitter: Please add others!
  7. Nicole4Jesus

    How does geology shape our understanding of the world?

    My second introductory post because we are always learning, right? I am 35 years old with an Associates degrees in: History, Arts & Humanities. I study people and our interactions across the ages and in the present. One of my scientific passions is Geology and Geophysics. Plate tectonics...
  8. T

    Groundwater Chemistry on an Island

    Good day all! I have a question about groundwater chemistry on an island. We have datasets over the last 40+ years and what can be seen is that the eastern and western side of the island differ from each other. On the western side there has been a distinct drop in pH over the last decades, and...
  9. rudransh verma

    Understanding Fog Formation and Dew Point from Wikipedia

    I read in Wikipedia that fog is formed when the water vapor in air is condensed to form liquid water that are suspended around condensation nuclei. Fog or clouds don't move from some place but appear in places through condensation. Now there is something about dew point which has to do with the...
  10. BillTre

    Deep Martian Geology: Signs of Plate Tectonics & Dynamo?

    I have long been intrigued about what's going on inside Mars. It shows signs of having had a very dynamic past, huge impact craters, huge volcanoes, massive systems of fissures and valleys. Some think that it went through a period of plate tectonics and had a geological dynamo that generated a...
  11. Lren Zvsm

    How big could a system of caverns be without collapsing?

    In the horror novel, the Descent, by Jeff Long, Earth has a system of deep caverns so extensive that they constitute a virtual "sub-planet," a kind of partial lower deck in the Earth's crust, whose mutated human inhabitants have horns and decorate their bodies with extensive scarification...
  12. L

    Help Drawing a Quaternary Deposits' Profile in Uppland, Sweden

    <mentor: moved to homework forums - no template okay in this case> Please I need help with this one! Drawing a Quaternary deposits’ profile The purpose with this practical is to understand how a map showing Quaternary accumulations is built up and how it may be interpreted. The information is...
  13. J

    Writing: Input Wanted What Makes Great Lakes Earth So Geographically Unique?

    https://orig00.deviantart.net/1603/f/2018/163/d/8/great_lakes_earth_map_by_jdailey1991-dce7cbj.jpg Dark brown=mountains. Light brown=uplifts. Black=Igneous provinces still visible today at their original extent with no consideration of erosion. Let us say that, in the future, some scientists...
  14. Amira bn

    Physics Is a job in physics possible? I have a bachelor's degree in geology

    Hello, I have a bachalor in geology, (3 years in university - USTHB ALGERIA - GEOLOGY -mineral resources) I want to get a job or an online job in physics/astrophysics/astronomy, how is that possible? will getting online certifications help? what are the things that i can do that will help me be...
  15. G

    Studying Self-Studying Scientific Computing for future graduate study

    I like to start a graduate program in scientific computing within the next 4-5 years, once my kids are a little older, my wife finishes her degree, and I have more money saved. In the meantime, I’m not going to waste time. Using the MIT challenge completed by Scott Young as inspiration, I’ve...
  16. Asmaa Mohammad

    How Does Underground Water Contribute to the Formation of Petrified Trees?

    My textbook says that formation of petrified trees is a result of a degradation and a sedimentation action of theunderground water, and then it goes on explaining that the underground water replaces the plant material in the tree with silica and other inorganic materials, which I think is a...
  17. F

    A Rajlich's Hypothesis - Ultrasonic Cavitation

    'Rajlich's Hypothesis is a physical hypothesis with a significance for geology. There exist macroscopic white lamellae inside quartz and other minerals in the Bohemian Massif and even at another places in whole of the world like wavefronts generated by a meteorite impact according to the...
  18. Asmaa Mohammad

    Geology: the environments of some sediments

    Homework Statement During a visit to mountainous area, students noticed a high mountain consists of 3 different parts: The top of the mountain consists of fossiliferous limestone. The middle of the mountain consists of fine grained rocks. The foot of the mountain consists of thick layers of...
  19. wolram

    B Geology of Ceres illuminates origin of organics

    Date: February 16, 2017 Source: Southwest Research Institute Summary: NASA's Dawn spacecraft recently detected organic-rich areas on Ceres. Scientists evaluated the geology of the regions to conclude that the organics are most likely native to the dwarf planet. Data from the spacecraft...
  20. Asmaa Mohammad

    The results of the glacials and interglacials in the ice age

    Hi, I have read that the Earth has undergone five ice ages, the latest one is the Quaternary glaciations. I know that in the ice age there are glacial periods and interglacial periods, and we are currently in an interglacial, I want to make sense what is the effect of those succsessive periods...
  21. P

    Programs 26 yo pharma journalist looking for hard science masters.

    Hi everyone, My details: Age: 26 Education: Bachelor's in Mass Media; Post-graduate Diploma in Journalism Work ex: 5 years for an international news agency covering pharmaceuticals and healthcare. I loved science in high school and was great at it, but couldn't continue due to some unavoidable...
  22. P

    Can a Journalism Background Lead to a Successful Career in Earth Sciences?

    Hi everyone, My details: Age: 26 Education: Bachelor's in Mass Media; Post-graduate Diploma in Journalism Work ex: 5 years for an international news agency covering pharmaceuticals and healthcare. I loved science in high school and was great at it, but couldn't continue due to some unavoidable...
  23. fresh_42

    If Feynman was a Geologist by Jun Cowan

    I have found this article on the net, which is fun to read. At least to all who are interested in Feynman's habits and attitudes. In the end it is about the "current state of geology", but it can be read as a reminder on how to do science in general...
  24. O

    General study tips for Physical Geology?

    Hey everyone, I am a CS major, and part of my curriculum has me taking 2 sequences in various sciences. Initially I wanted to do physics & chemistry. I ended up taking Physics I, but am unable to take Physics II next semester due to scheduling conflicts; thus this summer I am taking the first...
  25. T

    Programs To continue with the geosciences or go geotech engineering?

    I have a bachelors in geophysics and am currently deciding between attending a school for a masters in geoscience/geophysics and attending a school for a masters in geotechnical engineering. They are both funded to a degree, with the geoscience masters being extremely well funded versus the...
  26. E

    Emerald Mining Techniques: A Discussion on GeoChem and Geology

    Hello everyone, Wanted to introduce myself, i have topics i'd like to ask and share with the community about mining emeralds this is my core business. I hope to get some interesting discussions going in various forum threads here... sharing info and asking questions about GeoChem, Geology...
  27. T

    Are there coupled reactions in geology?

    I'm just wondering if all known coupled reactions are biological, or if there are some that geological and could have preceded the emergence of life on earth. In other words, are there some compounds in geochemistry that are much more abundant than you would expect if the reactions that produce...
  28. S

    Branch of study: geology + chemistry + mathematics

    Dear fellows, I was wondering about what lies inbetween the fields of geology, chemistry and mathematics. I mean, is there a branch of study that uses the three areas? Thanks in advance. JGSeg.
  29. JR Sauerland

    Programs As a geology major, I picking classes....

    Here are the required courses. I'll explain my options: Engineering calc 1/2 or Life Sciences calc 1/2 Physics with calc1/2 or physics without calc 1/2 Basically, that's my whole dilemma. Do I want Engineering Calc and Physics with calc, or without? Like does it make me any less skilled or...
  30. L

    Exploring Earth's Inner Core: The Latest on Polarity and Flux

    hello everyone, though not a scientist or professional student I have a fondness for Earth sciences, geology, seismology, ecology with interests in pole-shift theory, space/time relativity, archeology, anthropology and genetics, specifically, genetic genealogy. Here just to see read about...
  31. L

    Can I get into geology with a major in physics

    I want to get a career in geology but the school I am going to doesn't offer that. I am going because it is close to home and I am playing sports there. Can I get into geology with a major in physics or should I think of another career choice?
  32. M

    Minoring in Physics: Choosing Between Chemistry & Geology

    I'm currently doing a bachelors degree in applied physics, which minor goes along with physics? Chemistry or Geology? Which is in demand? (Our minors are 18 credit hours)
  33. F

    {Rocks} difference between sandstone and slate?

    Homework Statement sandstone is a sedimentary rocks while slate is a metamorphic rock come from mud stone with a high temperature and pressure, they are both stratified rocks, while chemically slates compose of Argil i.e Clay, while silica is the main ingredients of sandstone, my question is ...
  34. M

    Glad to find a site for rational people.

    I am in retired college teacher. I have taught geology, meteorology, chemistry, biology as well as astronomy. I guess I'm a person that just likes science and am a super generalist.
  35. bitznbitez

    Are Martian rock formations similar to those on Earth?

    I ran into a link from a NASA page over to an Astrobiology webzine. In the article it referenced "sedimentary rock" on Mars. I don't really care about all the other claims of this article, some rather fantastic claims frankly. Rather I am interested in the use of the phrase sedimentary...
  36. C

    How to get really deep depresion on an exoplanet?

    I want an exoplanet/exomoon with really deep depression. It would be the only place on that planet that's really habitable for humans without breating aid. Idea: -lower gravity (somewhere around 0.8 g) so the mountains should be able to be a bit taller -one supercontinent that's slowly...
  37. A

    Programs Should I major in Physics or Geology when I am terrible at math?

    Hello to all! First off, I would like to say that I have been reading through many of the forums and I quite enjoy reading everyone's posts and comments. I look forward to becoming a more active member on here! However, I would like to add my own question for academic guidance here as well...
  38. N

    Can hollow Earth theory be disproven?

    I have a friend who vigorously believes in hollow Earth theory. Your typical dreaded up conspiracy theory hippie type. I've looked around the internet and know there are threads similar to this but I'd like to open up a discussion here. How would one disprove hollow Earth theory? I can't imagine...
  39. A

    Engineering Geology vs. Petroleum engineering

    I'm not sure which one to choose so it all comes down to job prospects and pay. In the future, which is more likely to have better job prospects and a higher pay?
  40. Ritzycat

    Geology Graduates: Where Do They Work?

    Hello friends. I would like to know a bit about those who have gotten a BS in Geology. Where do geology graduates work? I understand the majority of them work for oil companies and whatnot. Do geology grads work anywhere else at all or are they almost exclusively in that industry?
  41. G

    Can runoff from street runoff purify contaminated aquifers near the ocean?

    If one digs a well near the ocean can the sand filter the salt out of ocean water? If so how far inland would one have to go?
  42. N

    Programs Which Geology Program Best Suits a Future in Resource Exploration?

    I'm a senior in high school applying for Geology programs now. The main three I'm considering are New Mexico State, Purdue, and Indiana University. I'm into science, but I also want good job prospects and travel, and geology seems like it provides all of that. I'd mostly be interested in working...
  43. M

    Programs Masters in physics after geology degree?

    Hi, I'm currently starting a geology degree and I was wondering if it would be possible after graduation to do a masters in physics, more specifically nuclear physics. I've contacted my universities head of physics and he said "geology can be acceptable" however I don't feel like this is a...
  44. T

    Programs Geology Major - considering a Geomatics & Spatial Analysis major

    I have recently switched into an Honours B.Sc. in Geology. I would like to get a second opinion on the potential applicability of studying Geomatics & Spatial Analysis in conjunction with the Geology specialization. I was previously enrolled in a chemistry degree so a great deal of my...
  45. G

    Geology vs Geography: Job Market & Pay Comparison

    Hello earthlings... I'm undecided about what to major in. But I do know that its got to be in a Earth science. At present I'm taking geology..in the summer I'll be taking geography. Then in the fall I'll be taking oceanography. My question is which one pays more and is more stable in the job market?
  46. G

    What is the difference between oceanography and marine geology?

    What's the difference between oceanography and marine geology?
  47. R

    Textbook for Structural Geology and Optical Mineralogy

    Hi guys, Please suggest a good introductory books for Structural Geology and Optical mineralogy, thanks :)
  48. R

    Most exciting field of Geology

    For all Geophysicist and Geologist out there, what is/are the exciting/favorite field/s of Geology and why? (please share your experience) :) thank you..
  49. C

    Engineering Geophysics Vs engineering geology

    I am quite confuse over this 2 course . I am not sure which to pick . Can anyone provide me some information regarding the career path difference for this 2 courses ( geophysics and engineering geology/geotechnical) Thank you
  50. P

    A good book on geology and/or meteorology?

    I am interested in a easy-to-read book on global geology and/or climate. The book will be ideal if it has discussions on how geology and climate changes, with detailed graphs (or data), due to seismic activities, external impacts like the solar wind from the Sun, and human-induced...