Three examples of locations in the world where non-subduction-related continental volcanism is occurring??

Question

Hi there,
i know the three examples of these regions.
but could u please explain for me each of area??? thx
1. East Africa - East African rift - divergent plate boundary.
2. New Mexico - New Mexico rift - potential future divergent plate boundary
3. Yellowstone - possible hot spot....

Please explain for me all the three of regions... thanks a lot!!!

Answer 1

1. East African Rift: caused by the divergence of two continental plates. When two continental plates break apart, it forms rifting and basaltic volcanism. During rifting, the continental crust is stretched (extension) and thinned. The extension creates rift valleys forms as a central graben, which is a downdropped fault block. These faults are pathways for basaltic magma (formed by mantle plumes), which rises from the mantle to erupt as CINDER CONES (type of volcano) and basalt flows (another type of volcano, but it doesn't exist anymore).

2. New Mexico: I don't know about this one. But I know about the volcanoes in the Northwest of Iceland that straddles with the Mid-Oceanic Ridge (ocean - ocean divergence). So, Iceland is separating (continent - continent divergence) causing rifting and at the same time, volcanic activities. Rifting causes basaltic magma to rise from the mantle because of the exitence of mantle plumes.

3. Yellowstone or why not Hawaii?: The volcanoes in Hawaii were not formed by subduction. Hawaii is composed of islands that are in the middle of a plate tectonic, not in a plate boundary. The volcanoes are formed by hot spots that were formed by mantle plumes.

**these volcanoes were formed because of the existence of mantle plumes. Mantle plumes are these very NARROW columns of hot mantle rock that rise through the mantle.**