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North Dakota: Legendary. Follow the trail of legends

Fossil Fuel Formation

How fossil fuels were formed:

<span class='figure-reader-id'>Stage 1</span> During the Paleozoic (pay-lee-ah-ZOE-ik) Era, which lasted from about 540 million years ago to about 250 million years ago, land that included North Dakota was <u>covered by shallow seas</u>. <span class='figure-reader-id'>Stage 2</span> <u>Plant life</u> grew along the edges of the seas, and the first <u>forests</u> appeared. The first <u>four-legged animals</u> also developed during this time. As algae, plankton and other organisms died, they accumulated in the sediment at the bottom of the sea. <span class='figure-reader-id'>Stage 3</span> Each time the <u>seas would recede</u> (go back), <u>decayed matter</u> from the living things would be <u>left behind</u>. <span class='figure-reader-id'>Stage 3</span> Each time the <u>seas would recede</u> (go back), <u>decayed matter</u> from the living things would be <u>left behind</u>. <span class='figure-reader-id'>Stage 3</span> Each time the <u>seas would recede</u> (go back), <u>decayed matter</u> from the living things would be <u>left behind</u>. <span class='figure-reader-id'>Stage 3</span> Each time the <u>seas would recede</u> (go back), <u>decayed matter</u> from the living things would be <u>left behind</u>. <span class='figure-reader-id'>Stage 4</span> Over millions of years, <u>layer after layer</u> of decayed plant and animal matter built up. <span class='figure-reader-id'>Stage 4</span> Over millions of years, <u>layer after layer</u> of decayed plant and animal matter built up. <span class='figure-reader-id'>Stage 5</span> Fast-flowing <u>rivers carried</u> and deposited <u>sand, silt, and clay</u> into the area. <br /> These <u>sediments</u> (small pieces of rock and dirt carried by water) were also <u>piled into layers</u>. <span class='figure-reader-id'>Stage 6</span> The pieces of sediment were <u>pressed together</u> and formed <u>sedimentary</u> (sed-ah-MEN-ter-ee) <u>rocks.</u> <span class='figure-reader-id'>Stage 6</span> The pieces of sediment were <u>pressed together</u> and formed <u>sedimentary</u> (sed-ah-MEN-ter-ee) <u>rocks.</u> <span class='figure-reader-id'>Stage 7</span> As decayed plants and animals became trapped in the sedimentary layers, <u>heat and the weight</u> of the sediments <u>pressed</u> them into material, which millions of years later became <u>fossil fuels</u> (petroleum, natural gas, and coal).
  
 
  • Petroleum and natural gas were created from very tiny plants and animals that had lived in oceans, or seas. Coal formed from plants that grew on land.
    • Hundreds to thousands of feet of earth continued to cover the dead plants and animals over the millions of years when the seas kept advancing and receding.
    • Even after the seas were gone, weight from the layers above continued to press down.
      • Heat and pressure "cooked" the organic materials into the liquid called petroleum.
      • The enormous weight and pressure together with very high heat created natural gas.

 

  • The rocks that contain coal in our area were formed millions of years later than the rocks that contain petroleum and natural gas.