Research helps to unlock key to Australian plate movement

Aug 11, 2008

(PhysOrg.com) -- New UQ volcano research is helping to unlock the mystery surrounding one of the world's most important tectonic events.

The study, which forms part of an ongoing research team effort in the University's Argon Geochronology in Earth Sciences (UQ-AGES), has found a major collision between the Australia plate and Earth's largest oceanic plateau, the Ontong Java Plateau (OJP), in the South Pacific, happened about 26 million years ago.

Earth Sciences senior lecturer Dr Kurt Knesel said geologists had long theorised about the collision however, it was not clear how or when the event occurred because the deep oceanic evidence was so inaccessible.

The UQ researchers used new ages for volcanoes in eastern Australia to yield information about plate migration and uplift histories, not retrievable from already available data.

Dr Knesel said team member and former UQ PhD student Dr Ben Cohen also looked for volcanic remains on the seafloor that corresponded in time and space to their estimate of the plateau's arrival.

“Ben noticed bends in the middle of two different seamount chains – tracks of volcanoes on the ocean floor – off of eastern Australia,” he said.

“The chains were offset at the same time that the volcano migration slowed on land, giving further evidence that the plateau arrived then and caused an abrupt westward plate excursion.”

Dr Knesel said the research helped discover notable patterns in the northward drift of Australia.

He said more than 100 volcanic samples were used as a kind of speedometer for the drift of the Australian plate.

“We think the immense plateau, which is roughly the size of Greenland, blocked Australia's northerly movement – rapidly altering the pattern of volcanic activity between 26 and 23 Ma,” he said.

“This momentous collision also initiated a dramatic plate reorganization.

“Before the collision, the Pacific plate was sinking or subducting below the Australian plate.

“However, the arrival of the plateau jammed and reversed this system, such that the Australian plate now sinks below the Pacific.”

The UQ team also included Head of Earth Sciences Associate Professor Paulo Vasconcelos and research officer in the University of Queensland Argon Geochronology in Earth Sciences (UQ-AGES) laboratory Dr David Thiede.

The establishment of The University of Queensland Argon Geochronology in Earth Sciences laboratory was partly-funded by the Australian Research Council and funding for the current project was provided through UQ-AGES contract research and an Australian Postgraduate Award to Dr Cohen.

The team's research formed part of the article “Rapid change in drift of the Australian plate records collision with Ontong Java plateau,” recently published in the journal Nature.

Provided by University of Queensland

Explore further: Computer simulations suggest aridification of Sahara occurred longer ago than thought

add to favorites email to friend print save as pdf

Related Stories

Deep Alpine Fault sensitive to nearby earthquakes

Aug 25, 2014

(Phys.org) —Victoria University of Wellington researchers have discovered that seismic waves produced by earthquakes happening several hundred kilometres away trigger activity deep beneath the Alpine Fault.

Recommended for you

First eyewitness accounts of mystery volcanic eruption

34 minutes ago

New light has been shed on one of the biggest volcanic eruptions in the last 500 years—the so-called 'Unknown eruption'—thanks to an unusual collaboration between a historian and a team of earth scientists at the University ...

Scientists monitoring Hawaii lava undertake risks

8 hours ago

New photos from the U.S. Geological Survey's Hawaiian Volcano Observatory give a glimpse into the hazardous work scientists undertake to monitor lava that's threatening to cross a major highway.

NASA sees Odile soaking Mexico and southwestern US

19 hours ago

Tropical Storm Odile continues to spread moisture and generate strong thunderstorms with heavy rainfall over northern Mexico's mainland and the Baja California as well as the southwestern U.S. NASA's Tropical ...

NASA sees Tropical Storm Polo intensifying

19 hours ago

Tropical storm warnings now issued for a portion of the Southwestern coast of Mexico as Polo continues to strengthen. Infrared imagery from NASA's Aqua satellite showed powerful thunderstorms around the center ...

User comments : 0