Survey reveals mineral rich fault lines

Sep 12, 2013 by Geoff Vivian
The view from the top of Mount Gascoyne, looking northward over the Glenburgh Terrane that forms the continent between the Pilbara and Yilgarn Cratons. Credit: S Johnson

The Geological Survey of Western Australia has confirmed that the remains of a small continent, about the size of Japan, is embedded in central Western Australia.

Geologist Simon Johnson says the Glenburgh Terrane, which includes Glenburgh Station near Gascoyne Junction, was trapped between tectonic plates two billion years ago.

He says the Pilbara and Yilgarn Cratons are the remains of that collided, forcing each others' edges up to form mighty .

These have slowly eroded down to become the Capricorn Orogen.

"They've now become as flat as the two bits on either side," Dr Johnson says.

"The only way we can recognise them is in the type of rocks, and by looking at the grade of the minerals in those orogenic belts which are different to the ones surrounding them."

This is one of many facts about the region's complex crustal architecture confirmed by recent seismic surveys.

Dr Johnson says up until now, had to rely on data generated by mining companies exploring what seemed to be likely , and aerial magnetic surveys.

These cheaper but less informative methods convey little information about the Earth's deeper structure.

He says labour-intensive seismic surveys, based on data from geophones laid manually on the ground, have given researchers detailed knowledge of the top 60 kilometres or so of the Earth's surface that is the crust.

They have discovered several major that were previously unknown.

"Faults which go from the surface of the Earth all the way down to the mantle play a significant role in mineralisation, because these can become pathways for metalliferous fluids," Dr Johnson says.

"These major fault lines are promising places to explore for minerals.

"The tectonic setting is also very important, so for example island arcs and the edges of continents are where you normally get lots of mineralisation.

"You can't necessarily tell where the major faults structures are just from geological mapping or those two-dimensional geophysical surveys.

"When we talk about architecture we are talking about understanding the crust in three dimensions."

The seismic surveys began after the Western Australian government made funds available under the Exploration Incentive Scheme, a part of the Royalties for Regions program, four years ago.

The Geological Survey of Western Australia is an ongoing program to gain a detailed knowledge of the state's geology and minerals which began in the 1880s.

Other states have similar programs.

Explore further: Study reveals ancient jigsaw puzzle of past supercontinent

More information: www.tandfonline.com/doi/abs/10.1080/08120099.2013.826735

add to favorites email to friend print save as pdf

Related Stories

Quakes unearth Australia's underground past

Jan 10, 2012

(PhysOrg.com) -- Researchers from The Australian National University have used the latest earthquake-measuring technology to image the tectonic plate beneath southeast Australia and reveal for the first time ...

The North American Cordillera: Constructive collisions

Apr 03, 2013

The mountain ranges of the North American Cordillera are made up of dozens of distinct crustal blocks. A new study clarifies their mode of origin and identifies a previously unknown oceanic plate that contributed ...

Toward a better understanding of earthquakes

Jul 05, 2012

The earth is shaken daily by strong earthquakes recorded by a number of seismic stations worldwide. Tectonic tremor, however, is a new type of seismic signal that seismologist started studying only within ...

Recommended for you

NASA image: Volcanoes in Guatemala

12 minutes 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 ...

NASA sees last vestiges of Tropical Depression Jack

17 hours ago

Tropical Cyclone Jack had weakened to a tropical depression when NASA and JAXA's Tropical Rainfall Measuring Mission (TRMM) satellite passed above on April 22, 2014 at 1120 UTC/7:20 a.m. EDT.

New discovery helps solve mystery source of African lava

20 hours ago

Floods of molten lava may sound like the stuff of apocalyptic theorists, but history is littered with evidence of such past events where vast lava outpourings originating deep in the Earth accompany the breakup ...

User comments : 0

More news stories

NASA image: Volcanoes in Guatemala

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 ...

On global warming, settled science and George Brandis

The Australian Attorney General, Senator George Brandis is no stranger to controversy. His statement in parliament that "people do have a right to be bigots" rapidly gained him notoriety, and it isn't hard to understand why ...

Phase transiting to a new quantum universe

(Phys.org) —Recent insight and discovery of a new class of quantum transition opens the way for a whole new subfield of materials physics and quantum technologies.

Imaging turns a corner

(Phys.org) —Scientists have developed a new microscope which enables a dramatically improved view of biological cells.