shales

geologists study shales to understand past environments.

the shale formation contains valuable natural gas reserves.

shales are often dark and rich in organic matter.

fracking is a technique used to extract oil from shales.

the company is exploring new shale deposits in the region.

black shales are particularly good source rocks for oil.

erosion gradually wears away the shales over time.

the shale's composition provides clues about its history.

shales can be easily split into thin layers.

we analyzed the shales for their geochemical properties.

the presence of fossils in shales indicates ancient life.

shales are sedimentary rocks formed from clay and silt.