University of Southampton researchers have found that rainwater can penetrate below the Earth's fractured upper crust, which could have major implications for our understanding of earthquakes and the generation of valuable mineral deposits.
It had been thought that surface water could not penetrate the ductile crust - where temperatures of more than 300°C and high pressures cause rocks to flex and flow rather than fracture - but researchers, led by Southampton's Dr Catriona Menzies, have now found fluids derived from rainwater at these levels.
Fluids in the Earth's crust can weaken rocks and may help to initiate earthquakes along locked fault lines. They also concentrate valuable metals such as gold. The new findings suggest that rainwater may be responsible for controlling these important processes, even deep in the Earth.
Researchers from the University of Southampton, GNS Science (New Zealand), the University of Otago, and the Scottish Universities Environmental Research Centre studied geothermal fluids and mineral veins from the Southern Alps of New Zealand, where the collision of two tectonic plates forces deeper layers of the earth closer to the surface.
The team looked into the origin of the fluids, how hot they were and to what extent they had reacted with rocks deep within the mountain belt.
"When fluids flow through the crust they leave behind deposits of minerals that contain a small amount of water trapped within them," says Postdoctoral Researcher Catriona, who is based at the National Oceanography Centre. "We have analysed these waters and minerals to identify where the fluids deep in the crust came from.
"Fluids may come from a variety of sources in the crust. In the Southern Alps fluids may flow upwards from deep in the crust, where they are released from hot rocks by metamorphic reactions, or rainwater may flow down from the surface, forced by the high mountains above. We wanted to test the limits of where rainwater may flow in the crust. Although it has been suggested before, our data shows for the first time that rainwater does penetrate into rocks that are too deep and hot to fracture."
Surface-derived waters reaching such depths are heated to over 400°C and significantly react with crustal rocks. However, through testing the researchers were able to establish the water's meteoric origin.
Funding for this research, which has been published in Earth and Planetary Science Letters, was provided by the Natural Environmental Research Council (NERC). Catriona and her team are now looking further at the implications of their findings in relation to earthquake cycles as part of the international Deep Fault Drilling Project, which aims to drill a hole through the Alpine Fault at a depth of about 1km later this year.
Notes to editors
1. "Incursion of meteoric waters into the ductile regime in an active orogen" by Catriona D. Menzies, Damon A. H. Teagle, Dave Craw, Simon C. Cox, Adrian J. Boyce, Craig D. Barrie, and Stephen Roberts is published in Earth and Planetary Science Letters, v. 399, p. 1-13. http://dx.doi.org/10.1016/j.epsl.2014.04.046
2. Picture: The Southern Alps Mountain Range, New Zealand. Rain and snow falling on the mountains percolate to great depths. Photo credit: Simon Cox
3. To arrange interview opportunities with Dr Catriona Menzies, please contact Steven Williams, Tel: 023 8059 2128, email: S.Williams@soton.ac.uk
4. Through world-leading research and enterprise activities, the University of Southampton connects with businesses to create real-world solutions to global issues. Through its educational offering, it works with partners around the world to offer relevant, flexible education, which trains students for jobs not even thought of. This connectivity is what sets Southampton apart from the rest; we make connections and change the world. http://www.southampton.ac.uk/ http://www.southampton.ac.uk/weareconnected
Follow us on twitter: http://twitter.com/unisouthampton
Like us on Facebook: http://www.facebook.com/unisouthampton
Steven Williams | Eurek Alert!
CO2 can be stored underground for 10 times the length needed to avoid climatic impact
28.07.2016 | University of Cambridge
Keep a lid on it: Utah State University geologists probe geological carbon storage
28.07.2016 | Utah State University
Transparent electronics devices are present in today’s thin film displays, solar cells, and touchscreens. The future will bring flexible versions of such devices. Their production requires printable materials that are transparent and remain highly conductive even when deformed. Researchers at INM – Leibniz Institute for New Materials have combined a new self-assembling nano ink with an imprint process to create flexible conductive grids with a resolution below one micrometer.
To print the grids, an ink of gold nanowires is applied to a substrate. A structured stamp is pressed on the substrate and forces the ink into a pattern. “The...
A new Fraunhofer MEVIS method conveys medical interrelationships quickly and intuitively with innovative visualization technology
On the monitor, a brain spins slowly and can be examined from every angle. Suddenly, some sections start glowing, first on the side and then the entire back of...
Researchers at the U.S. Department of Energy's (DOE) Ames Laboratory have discovered an unusual property of purple bronze that may point to new ways to achieve high temperature superconductivity.
While studying purple bronze, a molybdenum oxide, researchers discovered an unconventional charge density wave on its surface.
Munich Physicists have developed a novel electron microscope that can visualize electromagnetic fields oscillating at frequencies of billions of cycles per second.
Temporally varying electromagnetic fields are the driving force behind the whole of electronics. Their polarities can change at mind-bogglingly fast rates, and...
Breakup of continents with two speed: Continents initially stretch very slowly along the future splitting zone, but then move apart very quickly before the onset of rupture. The final speed can be up to 20 times faster than in the first, slow extension phase.phases
Present-day continents were shaped hundreds of millions of years ago as the supercontinent Pangaea broke apart. Derived from Pangaea’s main fragments Gondwana...
29.07.2016 | Event News
15.07.2016 | Event News
15.07.2016 | Event News
29.07.2016 | Power and Electrical Engineering
29.07.2016 | Life Sciences
29.07.2016 | Event News