Types of Geologist

Modern geology has come a long way since James Hutton published his theory of the Earth in the late 18th century. Today, geologists serve the public in many ways. A closer look at something as simple as the local convenience store can show just how much different types of geologists influence our lives every day.

♦ Exploration geology

Most convenience stores have gas pumps, and theirs are the ones we check first for the price of gas. It’s very high today – surely petroleum geologists must be rolling in cash these days!

They are doing pretty well, but there actually is a shortage (PDF file) of other types of economic geologists. This may be partly because the compensation is less than in oil companies, at least for those just starting out, and partly because few young people know about the field and so end up missing a big opportunity when planning a career. These geologists don’t work in the mines – they scout locations and may travel all over the country or throughout the world.

Business is booming. Lithium and nickel, for example, are always needed for cell phone batteries and other uses. Using information from the US Geological Survey, we can see that each car parked today at the store is built, on average, out of more than 35 mineral commodities, ranging from iron through aluminum and copper all the way to titanium, platinum and gold.

Besides precious metals, there’s minerals in them thar hills, including the crushed stone that was probably used as a base for the store and its parking lot, as well as for the highway and sidewalk that run along the side of the propery. The storefront may be covered in bricks made out of clay, or perhaps the builder used decorative stone. The building’s drywall is made from powdered gypsum. Laundry supplies on sale there may contain borax. The list goes on and on. Geologists are challenged to find these useful minerals in deposits that can be quarried or mined profitably but also in compliance with environmental regulations.

Economic geologists also look for coal and uranium, and they can find the right site for a big power dam and the large, heavy reservoir of water behind it. However, hydroelectric power isn’t the only connection geologists have with water.

♦ Hydrogeology

Your city water may come from an underground lake, called an aquifer, that formed when ground water was trapped in an impermeable layer of stone. Hydrogeologists locate aquifers and monitor their quality and availability. These are the geologists you might thank for the good water that store clerk used to make your coffee this morning.

They also were at the zoning board meeting before the store was built, giving expert testimony on potential ground water pollution from the proposed gasoline storage tanks and sewage lines. After zoning approval, perhaps a hydrogeologist also passed along tips to the construction company on how best to gently tilt the parking lot surface to avoid runoff that might contaminate the marshy area over in the next lot.

It might seem strange to have a geologist monitoring wetlands, but there is a strong connection between the marsh’s ecosystem and local geology, especially the soil that filters water and determines what plants can grow there.

♦ Marine science, fossils and plate tectonics

The water that leaves the marsh will eventually end up in the oceanic basin. The seas are special study areas for marine geologists, who examine the rocks found there, ocean sediments, and the geologic processes going on there and at the coasts.

While pondering all this, you might catch an ad for “Jurassic Park” on the big screen behind the counter inside the store and realize, that in a sense, marine geologists are just real-time paleontologists. After all, yesterday’s wetlands, ocean floors and other watery areas are today’s sedimentary rocks and fossil beds, now on dry land. Marine geologists often have to look through many kilometers of water to study the ocean floor as it is today, but paleontologists have to penetrate the depths of time as they to try to understand the way things used to be.

Back in the 1950s, marine geologists also helped reshape the entire field of geology when they came up with the first proof to support the highly controversial hypothesis called “continental drift” (think how the coasts of South America and Africa seem to have “drifted” apart).

Eventually research geologists in a variety of specialties worked out the theory of plate tectonics, which explains much more than continental drift. It is the reason why volcanoes often form near or in the sea, and it causes the biggest earthquakes in the world, including the magnitude 9 earthquake that struck northeast Japan on March 11, 2011.

As all this knowledge about Earth’s most violent events has accumulated, it has become possible to get a reasonable idea of the geological risks at a site, including the one chosen by the builders of our convenience store.

♦ Geological hazards

In addition to the usual concerns everywhere over landslides and flooding, a store owner in California might wonder how big of an earthquake to expect and whether a retrofitting is needed. In Anchorage, Alaska, there is also the potential for a nearby volcanic eruption. A convenience store operator on the coast of Japan has to factor in tsunami risks, too.

Seismologists, volcanologists, geophysicists and engineering geologists are some of the experts we all can turn to for geological risk assessments. Most of these specialists work for a government agency or perhaps in a large university nearby.

In America, the US Geology Survey is tasked with keeping track of earthquakes and volcanoes and the hazards they pose. Survey geologists often work on a team effort, for example, together with the National Park Service and the University of Utah to study Yellowstone Volcano. Back East, they have joined University of Memphis faculty members at the Center for Earthquake Research and Information to monitor the New Madrid earthquake zone as well as seismic events throughout the Southeast.

♦ Planetary geology

There is one subspecialty of geology that only has one member. An experienced geologist before he joined the Apollo 17 crew, Harrison Schmitt is the only one so far to ever conduct field studies on another planetary body.

However, there are many astrogeologists today, including those at the Lunar and Planetary Institute who shared Apollo-era lunar maps with Google for Google Moon and who also study the Earth from space.

As for more interplanetary field studies, perhaps one or more of those freshman geology students on a field trip, who are now lined up inside the store to pay for snacks while the instructor gasses up the van, will someday make it to Mars.

There are more types of geologist in the world today than it is possible to list. However, geology is a practical science, and just by visiting a local convenience store and reflecting a little bit on what we find there, we can see the many ways geologists influence our daily lives.