Images

High-definition image of sphalerite specimen with dark coloration and crystal structure.

USGS mineral specimen of sphalerite. High-definition image showing layered texture and metallic inclusions.

USGS mineral specimen of sphalerite. High-definition image showing crystal structure and dark coloration.

Isolated specimen featuring sylvite, halite, and polyhalite. High-definition image showing crystal textures and varied coloration.

High-definition image of argentiferous tetrahedrite specimen with dark coloration and metallic inclusions.

High-definition image of wolframite specimen with granular texture and black coloration.

High-definition image of zincite specimen with reddish-orange color and granular texture.

Conventional hydrothermal resources occur below the ground where three ingredients combine: heat, water and permeable rock. When heated water or steam is trapped in a porous rock below a layer of less permeable rock, a hydrothermal reservoir is formed.

Infographic of Electric-grade geothermal energy resources of the U.S. 

The USGS has assessed the Nation’s geothermal energy resources since the 1970s, updating assessments to include advancements in technology. An emerging resource is Enhanced Geothermal Systems (EGS).

Enhanced Geothermal Systems are an emerging resource that the USGS studies. To generate electricity from these systems, fractures are engineered into deep, low-porosity hot rocks to allow water to circulate. Then, the heated water is pumped back to the surface, where the thermal energy is used to move a turbine and generate electricity. 

Graph showing electricity generated by hydropower, wind, solar, bioenergy, and geothermal renewable energy sources in the U.S. from 2000-2020

Infographic about critical mineral commodities use in renewable energy, published online by the USGS Office of Communications and Publishing in June 2019.

This infographic shows some of the natural resources that the USGS Energy Resources Program studies, including oil and gas, geothermal, geologic hydrogen gas, carbon dioxide, wind, solar, coal, gas hydrates, uranium and water resources. 

This image shows a 3d visualization of geophysical data collected over the Idaho Cobalt Belt by the Earth Mapping Resources Initiative (Earth MRI). 

Diagram of how a Hydrogen Fuel Cell functions, with inputs and outputs. Courtesy of the Department of Energy’s Energy Information Administration.

The Kukpowruk River cuts through folded Cretaceous rocks in the central North Slope. These rocks were assessed by the USGS in 2017 and lie above the rocks assessed in the USGS 2021 Western North Slope assessment.

Jurassic rocks exposed in thurst-faulted structures near the southern limit of Western North Slope. In the subsurface farther north, these rocks may be reservoir rocks for natural gas.

Geologist hikes across folded Cretaceous rocks in the central North Slope. These rocks were assessed by the USGS in 2017 and lie above the rocks assessed in the USGS 2021 Western North Slope assessment.

USGS technicians at the USGS Gulf Coast #4 Bonham borehole in preparation for geophysical logging of the Austin Chalk Group and the Eagle Ford Group mudstones, Fannin County, Texas.

Bedding features in the core from the USGS Gulf Coast #4 Bonham borehole, in the Eagle Ford Group mudstones from a depth of about 401 feet, Fannin County, Texas. The Eagle Ford Group lies underneath the Austin Chalk and serves as the source rock for much of the Austin Chalk's petroleum.

Geologists discuss the geology of Jurassic rocks in thurst-faulted structures near the southern limit of Western North Slope.