Thursday, August 24, 2017

Archipelago-building volcanic hot spots moving scarcely if at all.

New scientific research suggests that volcanic hot spots—like the one that created the Hawaiian Archipelago—are far more stable than previously believed.

Stable, as in, they don’t move much on their own.

(Image: The line of volcanoes forming the 80-million-year-old Hawaiian-Emperor Chain. The bend is at 45 million years. Credit: NOAA.)

Hot spots are those plumes of molten rock that punch through the Earth’s crust from the mantle. They tend to create lines of islands or mountains as the crust moves across them.

The Hawaiian hot spot is believed to have been responsible for the Hawaiian-Emperor chain of islands and undersea volcanic peaks, which runs from Lo`ihi and Hawai`i Islands to the southeast, up to the Aleutians in the northwest.

It has been assumed that both the hot spot and the crust are in movement, but a team of researchers from Rice University’s Department of Earth Science, say their study suggests hot spots move very little, and often not at all.

Their paper in the journal Geophysical Research Letters is “Bounds on geologically current rates of motion of groups of hot spots.” In it, lead author Chengzu Wang and his collaborators, say “the rate of hot spot motion perpendicular to the direction of absolute plate motion…differs significantly from zero for only 3 of 10 plates and then” by very little.

What that means is that it is safe to use hot spot volcano progression as a way of calculating the historic movement of the tectonic plates that make up the planet’s crust, they say.

Rice University’s press release on the paper, headlined “Hot Spot at Hawaii: Not So Fast,” starts with the line, “Through analysis of volcanic tracks, Rice University geophysicists have concluded that hot spots like those that formed the Hawaiian Islands aren’t moving as fast as recently thought,”

Our previous coverage of scientific work suggesting that the hot spot is, in fact, doing a lot of moing, is here. 

For more on Hawaiian hot spot activity, see RaisingIslands articles on hot spot depth here. 

On the mysterious bend in the Hawaiian-Emperor chain here and here.

On the relationship of Kīlauea, Mauna Kea and Mauna Loa here

Clearly, this is dynamic stuff, but slow-moving.

© Jan TenBruggencate 2017

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