Images

A sample of lignite, the lowest rank of coal. It is primarily mined for burning in steam-generation power plants.

Clinker coal is the result of a seam of coal catching fire and burning so hot that it baked surrounding rock layers into brick-like formations. Some of the most famous clinker formations in the United States can be seen at the Theodore Roosevel National Park in North Dakota.

This sample is of peacock coal. Peacock coal is not a specific class of coal, but rather the name for an effect in which oxidizing materials in the coal create a dazzling array of colors on the surface of the coal. Usually it is short-lived, as the material fully oxidizes away shortly after exposed to air.

Most fossils occur in sedimentary rocks including shale, limestone and sandstone. The sandstone block shown here contains a large fossil palm leaf, found at the Coryell Coal mines in Colorado.

Geologists measuring petroleum source rocks in Triassic rocks along Surprise Creek in southern part of Western North Slope.

Faulted and folded Triassic, Jurassic, and Cretaceous rocks along Surprise Creek in southern part of Western North Slope. The Triassic and Jurassic rocks include petroleum source rocks from which oil was generated. Geologists in orange vests for scale.

Geologist describes petroleum source rocks in Triassic and Jurassic rocks along Surprise Creek in southern part of Western North Slope.

A carbon dioxide (CO₂) injection well drilled by the Southeast Regional Carbon Sequestration Partnership (sponsored by the U.S. Department of Energy) at the Cranfield CO₂ test site in Mississippi. The well was drilled to test the effectiveness of injecting and storing CO₂ in a deep saline reservoir.

A drill rig at the Mount Elbert test site in Alaska's North Slope, just west of Prudhoe Bay. USGS joined BP Exploration (Alaska) and the U.S. Department of Energy to drill a test well to study natural gas production from gas hydrate deposits. Read more about the Mt.

This image shows gas hydrates (the white material) in marine sediments from a test well drilled in the Indian Ocean in 2006 during the Indian National Gas Hydrate Program (NGHP) Expedition 01.

This image shows gas hydrates (the white material) in marine sediments from a test well drilled in the Indian Ocean in 2006 during the Indian National Gas Hydrate Program (NGHP) Expedition 01.

This image shows gas hydrates (the white material) in marine sediments from a test well drilled in the Indian Ocean in 2006 during the Indian National Gas Hydrate Program (NGHP) Expedition 01.

This image shows gas hydrates (the white material) in marine sediments from a test well drilled in the Indian Ocean in 2006 during the Indian National Gas Hydrate Program (NGHP) Expedition 01.

USGS scientist Bernard Hubbard conducting spectral measurements of soils and cover crops to ground truth satellite imagery being used to map soil erosion and runoff potential into the Chesapeake Bay watershed.

During Ocean Drilling Program Leg 204, nine sites were cored and wireline logged on the Oregon continental margin to determine the distribution and concentration of gas hydrates in an accretionary ridge setting, investigate the mechanisms that transport methane and other gases into the gas hydrate stability zone, and obtain constraints on physical properties of

This image shows an inukshuk, a stone cairn used by indigenous peoples in northern latitudes, particularly in places like northern Canada. 

A drill rig at the Mallik test site in Canada's Mckenzie Delta.  USGS joined the Geological Survey of Canada, JAPEX, and the Japanese National Oil Company to drill test wells for natural gas production from gas hydrate deposits.

View southward from Fortress Mountain Formation on Atigun syncline towards Brooks Range.  Trans-Alaska Pipeline, haul road, and Galbraith Lake in valley.  Location in Brooks Range foothills, about 90 miles southeast of Umiat.

View westward along Atigun River in Atigun Gorge.  Rocks in foreground are Lower Cretaceous Fortress Mountain Formation.  Rocks in gorge, along river, are Lower Cretaceous Okpikruak Formation.  Mountains on horizon are mostly carbonates of Carboniferous Lisburne Group.  Location in Brooks Range foothills, about 100 miles southeast of Umiat.

Storage tanks for produced water from natural gas drilling in the Marcellus Shale gas play of western Pennsylvania.