A new study finds the hotspots that created volcanic islands such as those of Hawaii, Iceland and the Galapagos Islands may often prove surprisingly cool.
These findings suggest that such hotspots may not always originate from giant plumes of scorching hot rock welling up from Earth’s core as previously thought.
Volcanoes are typically found near the borders of tectonic plates, generated from clashes between those giant slabs of rock as they drift on top of the mantle layer between Earth’s core and crust. Classic examples of such volcanoes are those that comprise the so-called Ring of Fire on the Pacific Rim.
However, volcanoes can sometimes erupt in the middle of tectonic plates. The sources of these hotspots could be mantle plumes. As tectonic plates move over such plumes, geologists think chains of volcanic islands can emerge.
Scientists have found that many hotspots are much cooler than previously thought, raising questions about their origins.”A substantial fraction of hotspots do not fit the classical plume model,” said Vedran Lekic, a seismologist.
These cooler hotspots may instead originate in the upper mantle, or from slow-moving deep plumes that have more time to cool, or from deep plumes that interact with and get cooled by swirling mantle rock.
“The classical view of plumes is not so much flawed than more complex than presented 30 to 50 years ago,” said co-author Carolina Lithgow-Bertelloni.
www.scitechdaily.com/how-do-volcanoes-form-scientists-find-surprisingly-cool-hotspots-under-earths-crust/