DAKOTA SANDSTONE
The main component of natural gas is probably formed when organisms decay on the muddy floor of a sea or lake.
When the mud hardens, the organisms are encased. The rock that results is called SOURCE ROCK.
Natural gas is held in and above reservoir rocks. RESERVOIR ROCKS are porous and permeable, allowing for absorption
of liquids and passage of natural gas. In the western United States, DAKOTA SANDSTONE is the reservoir rock formed
in the Cretaceous Period.
Natural gas and oil stop their movement toward the top of the earth's surface when they meet an impermeable
layer of rock. This impermeable CAP ROCK forms a barrier, causing gas and oil to pool beneath it.
NOW YOU CAN WRITE YOUR OWN TALL TALE!
 TALL
TALES
Tall Tales often are stories based on fact, but are full of imaginative exaggeration. The purpose
of a Tall Tale is to entertain as well as to educate.
In this Tall Tale, Dakota Sandstone is born. Then he joins together with his other ROCK friends
to form a band.
Think about the different kinds of rocks that are important for natural gas. What personalities
might they have? What kind of music might they make??
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