Mt. St. Helens - Lecture Notes

Eruption occurred in 1980 - a lot learned after eruption

Primary succession - resets land completely: volcanic eruption, meteorites

Density

• Decreasing melting temperature

  • partial melting

  • causes density to rise/go up

    • cools and creates a magma chamber

      • trapped gasses in magma

        • causes it to build up and erupt

          • successive eruptions over time

          • straddled volcanoes are due to this

            • ex: warmer upstairs in your house than basement

      • extinction of a volcano occurs if there is no magma source

Pioneer species growing

• small - not trees

• soil created which allowed more plants to grow

• causes ecosystem to become more diverse and stable and allow a forest to grow back eventually

  • centuries away from replacing Elk Grove Forest that was there but destroyed