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Guest Blog: Geology — Beyond the Rocks and Beards

Guest Blog: Geology — Beyond the Rocks and Beards

Daniel Segessenman is a Community Coordinator at Earth Science Information Partners (ESIP). In his guest blog, Segessenman explores the layers of his studies in geoscience and data. From seeing data science at new angles to considering adaptations of technology in the centuries-old strata of geological methods, Segessenman shares his love of this planet and the processes that shaped its rocks (and our understanding of Earth).

When people are asked what geologists do, survey results suggest that many individuals may respond with something like: “they just look at rocks and have beards” (Rogers et al., 2024). While this may not seem to be a negative perception initially, misconceptions of what geology is and what geologists study impacts our ability to communicate important findings with the public, connect with data science experts, and recruit a more representatively diverse body of future geologists.

If geologists aren’t just looking at rocks and growing beards, what do they do? How is geology relevant to critical issues in the modern day? How has geology evolved beyond traditional field-based descriptions of rock to incorporate 21st century data science methods? Can thinking like a geologist provide us with new perspectives? As a (generally) clean-shaven geologist, allow me to give you the inside scoop!

Unconformity at Jedburgh, Scotland. Etched by John Clerk for James Hutton in 1788. This image is often shown in introductory geology classes to highlight unconformities (missing time in the rock record) and that early geologists were aware of the depth of time recorded in Earth’s rock layers (Hutton, 1795).

What is geology and what do geologists do?

Geology is the general study of the solid Earth and terrestrial planets (e.g., Mars). The solid Earth happens to be made of rock, which makes rocks the best medium for understanding the processes that shape it and that are active on its surface! 

However, Geologists don’t just perform research on individual hand samples of rock, they also look at surface landforms (e.g. mountains and valleys), entire layers of rock, whole continents, and even Earth as a whole. Some subdivisions of geology include the interaction of other systems with rock, such as water (hydrogeology), Earth’s magnetic field (geophysics), and more. 

In addition to understanding the solid Earth as we observe it today, geology also includes the study of how Earth has changed through geologic time, which is on the scale of thousands, millions and even billions of years (learn more about how the age of the Earth is determined). 

Geology has long been associated with looking at and describing rocks in the field. We cannot bring a mountain back to the lab for study, so we must go to the rock layers where they naturally occur! However, many geologists work primarily in a lab, examining aspects of rocks from field samples such as (but certainly not limited to) their chemical compositions, microscopic structure, and physical properties (like how permeable to water they are). 

As with many other science fields over the past decades, geologists have also been compiling large datasets and applying principles of data science to provide critical new perspectives on Earth systems. Macrostrat, the Paleobiology Database, and mindat.org, are all great examples of platforms for data science in geology.

macrostrat.org, a data platform of North American rocks, their locations, their descriptions, and their ages. Powers the mobile app Rock’d, which allows you to explore the rocks beneath your feet!

Geology and you… or rather, geology and us

Ok, geologists study the solid Earth today and through time. But how is that relevant to humans in their day-to-day lives?

  • Do you drink water? I certainly hope so!  Many of us drink water that is sourced from beneath Earth’s surface. Water for agriculture is commonly sourced from aquifers, which are layers of rock that collect and hold groundwater. Hydrogeologists study the locations, recharge rates, and contamination potential of water bearing aquifers globally (learn more about hydrogeology)
  • Do you use technology? Rare Earth elements commonly used in our technology often needs to be mined from beneath Earth’s surface. Geologists study how deposits like this form and how we can use that knowledge to locate previously unknown deposits of critical mineral resources (learn more about Rare Earth Elements).
  • Do you live in an area prone to earthquakes? Seismologists study the hidden structure of plate boundaries using remote sensing methods to better understand the frequency, magnitude and hazard potential of earthquake zones (learn more about seismology).
  • Are you concerned about Earth’s changing climate? Predictions of future climate scenarios are of critical importance to informing current policy affecting emissions from human activity on Earth. Geologists study how climate has changed in Earth’s past (for example, the Miocene Climactic Optimum; 13-17 million years ago). They also assemble databases of proxies characterizing past climate change and work with climate modelers to incorporate their data into simulations of future climate scenarios (learn more about ancient climate analogues for future climate prediction).

I could go on and on, but I hope you are starting to see the importance of geology beyond the rocks and beards. While many of us may not think about the rocks beneath our feet very often, there are numerous secrets hidden within them that help us to learn about Earth, the only home of humanity in the vast universe!

Geologic time is data

Every geologist learns about the geologic time scale. The geologic time scale is the product of a massive data compilation of rocks and their characteristics, fossils, numerical dates measured from the decay of radioactive elements, geochemical values, stratigraphic correlation schemes and more. 

It incorporates essentially everything we know about the Earth’s geologic past using the data geologists have collected for over 300 hundred years (learn more about the geologic time scale). This information is compiled and interpreted to provide separations of Earth’s very long history into meaningfully distinct chunks at multiple resolutions.

The Phanerozoic (last 539 million years; ~1/9th of Earth’s history) and Precambrian (all Earth history before 539 million years ago) are eons separated by the widespread appearance of animal fossils in the rock record in the Phanerozoic. The Phanerozoic eon consists of the Paleozoic, Mesozoic and Cenozoic (current) eras, which roughly separate animals into pre-Dinosaur, Dinosaur, and post-Dinosaur eras, respectively. 

However, that’s a very dinosaur-centric way of looking at time. The Phanerozoic eras and periods also define different chapters in the assembly and breaking up of the supercontinent Pangea and how Earth systems changed in response. 
Then there are periods, each of which are made of stages, all of which represent unique states of the ancient Earth (learn more about Earth history).

Do not be deceived by the relative simplicity of this figure. This is the summation of over 300 years of geologic information and investigation of Earth history. It is a living document that changes as our understanding of Earth history changes (Cohen et al., 2013).

Thinking like a geologist in the digital age

If you thought I could go on and on about why geology is relevant to our day-to-day lives, do not get me started on Earth history! I LOVE Earth history! However, I do have a point in bringing this up. 

Geology is interdisciplinary by necessity. 

Every system on Earth interacts with some other system on Earth and systems outside of Earth. Every fossil, every radiometric date, every analysis of a fault or fold, every rock description, every chemical analysis of rocks, etc., contributes in some way to our understanding of Earth history and thus influences the geologic time scale. 

This understanding of the solid Earth has a resolution that scales from individual particles and how they behave all the way up to how the movement of planets in our solar system affect each other. 

The temporal resolution is important too! Different geologic processes are important at different time scales. For instance, sea level changes over tens to hundreds of millions of years are controlled by things like continental plate dynamics and seafloor spreading rates. Sea level changes on the order of millions to thousands of years are strongly influenced by the amount of ice present on Earth’s surface. Sea level can change locally in minutes to hours due to storm surges or tsunamis. 

Geologists studying Earth as a global system must consider pretty much everything!

From this perspective of deep time and interconnectivity, geology provides a unique perspective applicable to data science. No Earth system exists in a vacuum, everything on Earth is interconnected. For instance, wildfire frequency is influenced by climate and vegetation density. Vegetation density is influenced by climate and soil types. Soil types are influenced by microbiomes and bedrock geology. Bedrock geology is influenced by ancient climate and accommodation space for sediments. 

When considering Earth science data platforms and how to construct them or make them more interoperable, perhaps it could be helpful to think like a geologist. 

What other Earth systems are relevant to your data? How do these systems interconnect and interact? What timescales are most important for your data? How might our perspectives of this data change with different resolutions of time and/or space? How does this data fit in with the larger whole of all Earth systems? These are the types of questions a geologist may ask!

This image is a simple expression of the interconnectedness of Earth systems and the interactions between that result in the rock record as we observe it today. Created by Shanan E. Peters and Bridget Diem as the symbol for the Macrostrat lab group at the University of Wisconsin-Madison.

More than Beards and Rocks

For you, dear reader, I hope that the next time you consider an interesting rock, a beautiful landscape, Earth science data, the impact of humanity on nature, or even the mysteries of life, that you too will see the value of thinking like a geologist. To see past the surface and the immediate, to see the deep history, the interconnectedness underneath. That we are not separate from nature, but rather that we are but one small part of it.

NASA Lunar Reconnaissance Orbiter (LRO) recreation of astronaut Frank Borman’s 1968 ‘Earthrise’ photo.

What do I do as a geologist?

My area of interest is in using data science approaches to explore how Earth’s surface geology and life on Earth have co-evolved in the past. I’m particularly interested in the oldest fossils of animals found in rocks of the Ediacaran Period (539-635 million years ago) and what the Earth was like back then (see Segessenman and Peters, 2023 if you are interested in more about my latest research). I hope that my research will provide new insights into animal development on Earth and characteristics of planets that may host complex multicellular life beyond Earth! If you’re interested in hearing more about this subject, or if you’re interested in my personal story of how I became interested in geology and Earth history, check out the recorded presentation linked below I gave for We All Count’s “Talking Data Equity” series.


Works Cited

Cohen, K.M., Finney, S.C., Gibbard, P.L. & Fan, J.-X. (2013; updated; v2023/09) – The ICS International Chronostratigraphic Chart. Episodes 36: 199-204. https://stratigraphy.org/chart 

Hutton, J. 1795. Theory of the earth, with proofs and illustrations. Edinburgh. Digitized version courtesy of The Linda Hall Library of Science, Engineering & Technology. https://catalog.lindahall.org/discovery/delivery/01LINDAHALL_INST:LHL/1286747210005961 

Rogers, S.L., Giles, S., Dowey, N., Greene, S.E., Bhatia, R., Landeghem, K.V., and King, C. 2024. “you just look at rocks, and have beards” Perceptions of Geology From the United Kingdom: A Qualitative Analysis From an Online Survey. Earth Science, Systems and Society. Doi: 10.3389/esss.2024.10078

Segessenman, D.C., Peters, S.E. 2023. Transgression-regression cycles drive correlations in Ediacaran-Cambrian rock and fossil records. Paleobiology v. 50(1). Doi: 10.1017/pab.2023.31


This blog was written by Daniel Segessenman with edits by Allison Mills from ESIP.

ESIP stands for Earth Science Information Partners and is a community of partner organizations and volunteers. We work together to meet environmental data challenges and look for opportunities to expand, improve, and innovate across Earth science disciplines.Learn more esipfed.org/get-involved and sign up for the weekly ESIP Update for #EarthScienceData events, funding, webinars and ESIP announcements.