See List of periods and events in climate history for a timeline list focused on climate.The time from roughly 15,000 to 5,000 BC was a time of transition, and swift and extensive environmental change, as the planet was moving from an Ice age, towards an interstadial (warm period).Helens "Louwala-Clough," or "smoking mountain." The modern name, Mount St.Helens, was given to the volcanic peak in 1792 by Captain George Vancouver of the British Royal Navy, a seafarer and explorer.Before 1980, snow-capped, gracefully symmetrical Mount St.Helens was known as the "Fujiyama of America." Mount St.Pink lines denote convergent boundaries, blue lines denote divergent boundaries and yellow spots denote hotspots.
Ages for component minerals varied from 0.34 /- 0.06 Mya to 2.8 /- 0.6 Mya. It was believed that each forest was destroyed by volcanic activity, to be replaced in the course of time by a new forest.It was argued that this evidence could not support a young age for the earth. Harold Coffin carried out a detailed investigation of these petrified forests and discovered that they strongly support the catastrophic model.Some dangerous volcanoes in "populated areas" appear many times: so Santorini, six times and Yellowstone hotspot, twenty-one times.The timeline lists events in the external environment that have influenced events in human history.As many of the trees stand upright in an apparent position of growth, it was accepted that they were the remains of an actual forest. Closer examination reveals that the petrified trees have no bark with side branches and root stocks ripped off.This is inconsistent with trees being covered with ash while in a position of growth.Sea levels rose dramatically (and are continuing to do so), land that was depressed by glaciers began lifting up again, forests and deserts expanded, and the climate gradually became more modern.In the process of warming up, the planet saw several "cold snaps" and "warm snaps", such as the Older Dryas and the Holocene climatic optimum, as well as heavier precipitation.Before the Holocene epoch, the criteria are less strict because of scarce data availability, partly since later eruptions have destroyed the evidence.So, the known large eruptions after the Paleogene period are listed, and especially those relating to the Yellowstone hotspot, the Santorini, and the Taupo Volcanic Zone.This timeline is for use with the article on environmental determinism.For the history of humanity's influence on the environment, and humanity's perspective on this influence, see timeline of the history of environmentalism. Helens, located in southwestern Washington about 50 miles northeast of Portland, Oregon, is one of several lofty volcanic peaks that dominate the Cascade Range of the Pacific Northwest; the range extends from Mount Garibaldi in British Columbia, Canada, to Lassen Peak in northern California. Helens a composite volcano (or stratovolcano), a term for steepsided, often symmetrical cones constructed of alternating layers of lava flows, ash, and other volcanic debris.