Images

Hornfels rocks are metamorphic rocks. They usually start out as sedimentary rocks like sandstone or shale, but then volcanic material pushes up from below and bakes the sedimentary rock into a metamorphic one. Hornfels are known for being exceptionally tough and durable. This one is from Chantilly, VA.

Diopside crystals are made up of Magnesium, Calcium, Silicon and Oxygen, and are usually found in metamorphic rocks. These crystals have developed in some Cockeysville Marble from Texas, Maryland.

Eklutna River traveling under two bridges

Conglomerates are sedimentary rocks that are made up of various fragments of rock interspersed with finer grained material. This particular conglomerate was deposited as a fan on the northwest side of the Culpeper Basin.

 Mud rotary drilling of an observation well in Locust Valley, New York

Spring sampling location along Little Sandy River in southern Wyoming. Groundwater discharge that flows into the Upper Colorado River Basin varies in response to drought, which is likely due to aquifer systems that contain relatively young groundwater, according to a new U.S.

A USGS benchmark at the USGS National Center.

Granite is an igneous rock that we’ve used for building materials for thousands of years. It’s name comes from the Latin word “granum,” meaning “grain,” which refers to the grains of quartz and feldspar that define granite. This one is from the Barre formation in Vermont.

USGS scientist collects noble gas sample from spring site near Roaring Judy, Colorado. Groundwater discharge that flows into the Upper Colorado River Basin varies in response to drought, which is likely due to aquifer systems that contain relatively young groundwater, according to a new U

A long, hot hike was not needed to see red lava today. Vigorous spattering from Kīlauea Volcano's summit lava lake was visible from the Jaggar Museum Overlook in Hawai‘i Volcanoes National Park as of this afternoon. The lava lake surface, measured at 25 m (82 ft) below the vent rim this morning, was high enough for the spattering to be seen from afar.

Water quality and sampling equipment deployed at spring site near Roaring Judy, Colorado. Groundwater discharge that flows into the Upper Colorado River Basin varies in response to drought, which is likely due to aquifer systems that contain relatively young groundwater, according to a new U.S

View of the Willow Creek Reservoir near Heppner, OR

Comparison of water from an underground spring in Georgia  during non-drought and drought periods.
Radium Springs, Albany, Georgia, USA

Eagle Creek at Zionsville, IN - ADCP bridge measurement

Eagle Creek at Zionsville, IN bridge

Male Lapland Longspur in dwarf shrub mat habitat.  This photo was taken on the Seward Peninsula as part of the Changing Arctic Ecosystem Boreal-Arctic Transition Zone program.

Catch of forage fish from a trawl in Cook Inlet, Alaska. Trawling was part of an assessment of abundance, distribution and species composition of forage fish in marine waters in lower Cook Inlet.

Harmful algal blooms turn water in Milford Lake emerald green

Harmful algal blooms turn water in Milford Lake emerald green

A view of Milford Lake from a timelapse camera installed near the water's edge. In the background the otherside of the lake and a bridge can be seen.

Palila, a critically endangered Hawaiian bird found only the slopes of Mauna Kea volcano, Hawai‘i Island, Hawai‘i, have faced several threats including invasive cats, rats, and mongoose, and loss of habitat. Dr. Paul Banko has spent decades of his career studying palila populations and threats. In this photo, Dr.