Hawaiian hotspot variability attributed to small-scale convection

Jun 29, 2011
Three-dimensional image showing predicted mantle temperatures beneath the Hawaiian hotspot

(PhysOrg.com) -- Small scale convection at the base of the Pacific plate has been simulated in a model of mantle plume dynamics, enabling reasearchers to explain the complex set of observations at the Hawaiian hotspot, according to a new study posted online in the June 26th edition of Nature Geoscience.

"A range of observations cannot be explained by the classical version of the mantle plume concept," says Maxim Ballmer, Post Doctoral Researcher in the Department of and Geophysics in the School of Ocean and Earth Science and Technology (SOEST) at UHM. These observations include the occurrence of secondary volcanism away from the hotspot (e.g., Diamond Head, Punchbowl, Hanauma Bay), as well as the chemical asymmetry (Mauna Loa compared to Mauna Kea) and temporal variability (over timescales greater than 10,000,000 years) of hotspot volcanism itself.

Ballmer and colleagues, including advisor Garrett Ito, Associate Professor, in the Department of Geology and in the SOEST at UHM, designed a geodynamic model of the mantle that successfully predicts a large range of observations thus providing insight into the composition and dynamics of the mantle. Ballmer says the findings of their model, "make an important contribution toward understanding the origin of volcanism away from plate boundaries. This is a long-standing question in our community that potentially provides general insight into the dynamics of our planet, and particularly into the make-up of the deepest mantle, from where mantle plumes originate. For many reasons, understanding the deepest mantle is relevant for questions about the early days of Earth, and the origin of water and life."

These findings came as a bit of a surprise. Although small-scale convection was one hypothesis for explaining late-stage rejuvenated volcanism on the islands, Ito reports, "this study is the first to qualitatively explore this mechanism and to show that it can explain both rejuvenated as well as arch volcanism, well away from the islands."

As a next step in understanding mantle dynamics, Ballmer hopes to explain some of the characteristics of the Hawaiian plume that have been revealed by SOEST – UHM colleague Cecily Wolfe using seismic earthquake tomography. To do this, he will simulate a thermochemical , which in some ways behaves similarly to the upwellings in lava lamps. A thermochemical plume is a plume that is hot (i.e. thermally buoyant), but compositionally dense. Such a plume typically behaves more complicatedly than a classical plume.

Explore further: Microscopic organism plays a big role in ocean carbon cycling

More information: Nature Geoscience: Spatial and temporal variability in Hawaiian hotspot volcanism induced by small-scale convection DOI:10.1038/NGEO1187

Provided by University of Hawaii

4 /5 (2 votes)

Related Stories

New explanation for Hawaiian hot spot

May 27, 2011

(PhysOrg.com) -- Scientists in the US have suggested that volcanic activity in Hawaii could be fed by a giant hot rock pool 1,000 kilometers west of the islands and in the Earth’s mantle, rather than ...

Hawaiian hot spot has deep roots

Dec 03, 2009

(PhysOrg.com) -- Hawaii may be paradise for vacationers, but for geologists it has long been a puzzle. Plate tectonic theory readily explains the existence of volcanoes at boundaries where plates split apart ...

Mount Etna's mystery explained?

Oct 07, 2010

Internationally renowned geophysicist Dr Wouter Schellart has developed the first dynamic model to explain the mystery of the largest and most fascinating volcano in Europe, Mount Etna.

Recommended for you

How productive are the ore factories in the deep sea?

13 hours ago

About ten years after the first moon landing, scientists on earth made a discovery that proved that our home planet still holds a lot of surprises in store for us. Looking through the portholes of the submersible ...

NASA image: Volcanoes in Guatemala

18 hours ago

This photo of volcanoes in Guatemala was taken from NASA's C-20A aircraft during a four-week Earth science radar imaging mission deployment over Central and South America. The conical volcano in the center ...

User comments : 0

More news stories

Untangling Brazil's controversial new forest code

Approved in 2012, Brazil's new Forest Code has few admirers. Agricultural interests argue that it threatens the livelihoods of farmers. Environmentalists counter that it imperils millions of hectares of forest, ...

Study links California drought to global warming

While researchers have sometimes connected weather extremes to man-made global warming, usually it is not done in real time. Now a study is asserting a link between climate change and both the intensifying California drought ...

Genetic code of the deadly tsetse fly unraveled

Mining the genome of the disease-transmitting tsetse fly, researchers have revealed the genetic adaptions that allow it to have such unique biology and transmit disease to both humans and animals.