Rocky Mountains

By 2040096
  • Period: 544 BCE to 245 BCE

    544 million to 245 million years ago

    During the long Paleozoic Era, the area where the Rocky Mountains are was mostly submerged. Near the end of the era, two tectonic plates collided and caused a range known as the Ancestral Rocky Mountains to rise. These mountains eroded fairly quickly.
  • Period: 250 BCE to 65 BCE

    250 million to 65 million years ago

    During the Mesozoic Era, the Rocky Mountain uplift began. The rocky mountains started looking like they do today. NPS says "Giant blocks of ancient crystalline rock, overlain by younger sedimentary rock, broke and were thrust upward."
  • Period: 65 BCE to

    65 million years ago to today

    During the Cenozoic Era, the Rocky Mountain Front Range was lifted 5,000 feet to its present height.