In strictest geological terms, a volcano is a vent from which magma and other substances erupt to the surface or it is a landform composed of the volcanic debris and solidified lava found near the opening of a vent. These landforms have been in existence since the beginning of volcanic activity. One such volcano would be Mauna Loa. It is classified as a shield volcano; a landform that is usually huge with gentle slopes and many layers of what was once fluid lava. The opposite would be Mount Fuji. This volcano is a classic stratovolcano. It has steep slopes built of layer upon layer of lava and ash. A third type is a submarine volcanic landform found upon the Icelandic seafloor.
Geologists have discovered that the interior heat from large planetary bodies such as Earth has difficulty escaping by such common processes as radiation or conduction and instead uses a method of convection, a partial melting of the Earth’s crust and mantle whereby magma rises to he surface.
Volcanoes give evidence of the directions and rates of motion of the Earth’s tectonic plates. Their study comes under the banners of geophysicists, geochemists, geologists, biologists and meteorologists. Their disciplines cover everything from the roots of volcanoes, signs of future eruptions, the plants and animals who find volcanoes a suitable habitat, and the effects of volcanic dust and gases on the atmosphere, the weather and climate.
Volcanoes enrich the soil making it fertile. One will find valuable mineral deposits and geothermal energy. Over time they even benefit by recycling the planet’s hydrosphere and atmosphere. They create beautiful scenery that mystifies the onlooker. But as we all know too well volcanoes are associated with a long list of destructive hazards. They produce legendary lava flows, explosions, toxic gas clouds, dangerous ash falls, pyroclastic flows, avalanches, tsunamis and mudflows. Secondary is the property damage and crop loss.
If you hunt for rocks near the surface of a vent you will find four major types or what they call clans. There are basalt, andesite, dacite and rhyloite. The range in silica content from 50% to 75%. The higher the silica content the more viscous the rock.
. When the archaeologist finishes his/her studies it s the geologist who continues our journey into the remotest areas of earth’s antiquities. Rocks remember.
Rocks remember. When the archaeologist finishes his/her study it s the geologist who continues our journey into the remotest areas of Earth’s antiquities.
