Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Moved by Geodynamics

22.06.2010
Underground Forces: Deformation Processes in Gravel Deposits

Deformation bands in the gravel layers of the Eisenstadt-Sopron Basin form as a result of heterogeneous displacement in the surrounding sediment. This is caused by gradients in the deformation intensity, which occur both parallel and perpendicular to a fault. These findings from a project funded by the Austrian Science Fund (FWF) will help scientists to reach a better understanding of both basic geological processes and the formation and structure of oil and water reservoirs.

As impressively demonstrated by the Himalayas and Pacific oceanic trenches, tectonic forces can really get things moving. However, even these dramatic geological manifestations move just a few millimetres or centimetres per year. Other phenomena associated with geological forces, known as deformation bands, are also subject to movement on a similar scale. These bands arise in soft porous rocks, such as sandstone. They occur where coarse-grained rocks are displaced by the shear forces of the overlying or underlying rock horizons, or undergo a change in volume. In contrast to what is known as a fault, in which the layer of rock ruptures, in the deformation bands, sediment grains are merely fractured or reorganised. The porosity of the rock and, therefore, its permeability to fluids, changes as a result of this process. Deformation bands thus contribute to the formation and structure of oil or water reservoirs. Attaining a better understanding of their effect on the surrounding rock is the aim of a project being carried out at the Department for Geodynamics and Sedimentology at the University of Vienna.

IT'S ALL ABOUT THE GRAIN!
As part of this study, project leader Dr. Ulrike Exner and her team successfully demonstrated that, due to their relatively coarse grain size, deformation bands in gravels in the Eisenstadt-Sopron Basin near Lake Neusiedl on the Austrian-Hungarian border display a gradient in the strain intensity. This gradient runs from the undeformed neighbouring rock to the middle of the deformation band. As Dr. Exner outlines: "The stresses responsible for this act perpendicular of the deformation band. However, we discovered that a displacement gradient also exists parallel to the fault zone. The largest displacement can be measured in the middle of the deformation band. It decreases above and below this point towards the tips of the band." The presence of these two differently oriented displacement gradients causes folding in the surrounding sediment layers.
REVERSE DRAG
Dr. Exner explains the further effects of these heterogeneous deformations in the rock as follows: "The surrounding rock horizons begin to deform. This effect is known as reverse drag. In closely-spaced deformation bands, such drags can even overlap. The resulting geometrical patterns become increasingly complex." However, as Dr. Exner also states, models exist that can explain these patterns: "The so-called domino model explains these patterns in terms of the rotation of blocks of rock between the different deformation bands. Because the rock is still soft and the deformation proceeds very slowly, the behaviour of these blocks is ductile and they are easily deformed."

In the deformation bands examined as part of this project, the ratio between the displacement of the layers of rock pushing against each other and the length of the deformation bands is striking. These ratios, which range from 1:100 to 1:10, are unusually large. According to Dr. Exner, this could facilitate the generation of reverse drag.

Despite the fact that the processes studied by Dr. Exner unfold below the surface of the earth, her work is of direct and practical relevance to everyday life above ground: deformation bands mainly form in porous rock which, due to the presence of numerous pores, also acts as a reservoir for oil or water. Deformation bands alter porosity and can therefore influence the extraction of oil or water. Moreover, the relevance of this FWF project also extends to heavenly heights: the calcareous sandstone, also referred to as Leithakalk (Miocene limestone found in Central Europe), from which St. Stephen's Cathedral in Vienna is built, originates from the Eisenstadt-Sopron Basin. Its porosity - and thus also its response to environmental impacts and protective measures - is also influenced by deformation bands.

Data were presented at the "European Geosciences Union General Assembly 2010", 2.-7. May in Vienna, Austria.

Image and text available from Moday, 21th June 2010, 9.00 a.m. CET onwards:
http://www.fwf.ac.at/en/public_relations/press/pv201006-en.html
Scientific Contact:
Dr. Ulrike Exner
University of Vienna
Department for Geodynamics and Sedimentology Althanstrasse 14 1090 Vienna, Austria T +43 / 650 / 35 66 948 E ulrike.exner@univie.ac.at
Austrian Science Fund (FWF):
Mag. Stefan Bernhardt
Haus der Forschung
Sensengasse 1
1090 Vienna, Austria
T +43 / 1 / 505 67 40 - 8111
E stefan.bernhardt@fwf.ac.at
W http://www.fwf.ac.at
Copy Editing & Distribution:
PR&D - Public Relations for Research & Education Campus Vienna Biocenter 2 1030 Vienna, Austria T +43 / 1 / 505 70 44 E contact@prd.at W http://www.prd.at

Marta Korinkova | PR&D
Further information:
http://www.fwf.ac.at
http://www.fwf.ac.at/en/public_relations/press/pv201006-en.html

More articles from Earth Sciences:

nachricht PR of MCC: Carbon removal from atmosphere unavoidable for 1.5 degree target
22.05.2018 | Mercator Research Institute on Global Commons and Climate Change (MCC) gGmbH

nachricht Monitoring lava lake levels in Congo volcano
16.05.2018 | Seismological Society of America

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: LZH showcases laser material processing of tomorrow at the LASYS 2018

At the LASYS 2018, from June 5th to 7th, the Laser Zentrum Hannover e.V. (LZH) will be showcasing processes for the laser material processing of tomorrow in hall 4 at stand 4E75. With blown bomb shells the LZH will present first results of a research project on civil security.

At this year's LASYS, the LZH will exhibit light-based processes such as cutting, welding, ablation and structuring as well as additive manufacturing for...

Im Focus: Self-illuminating pixels for a new display generation

There are videos on the internet that can make one marvel at technology. For example, a smartphone is casually bent around the arm or a thin-film display is rolled in all directions and with almost every diameter. From the user's point of view, this looks fantastic. From a professional point of view, however, the question arises: Is that already possible?

At Display Week 2018, scientists from the Fraunhofer Institute for Applied Polymer Research IAP will be demonstrating today’s technological possibilities and...

Im Focus: Explanation for puzzling quantum oscillations has been found

So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics

Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...

Im Focus: Dozens of binaries from Milky Way's globular clusters could be detectable by LISA

Next-generation gravitational wave detector in space will complement LIGO on Earth

The historic first detection of gravitational waves from colliding black holes far outside our galaxy opened a new window to understanding the universe. A...

Im Focus: Entangled atoms shine in unison

A team led by Austrian experimental physicist Rainer Blatt has succeeded in characterizing the quantum entanglement of two spatially separated atoms by observing their light emission. This fundamental demonstration could lead to the development of highly sensitive optical gradiometers for the precise measurement of the gravitational field or the earth's magnetic field.

The age of quantum technology has long been heralded. Decades of research into the quantum world have led to the development of methods that make it possible...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Save the date: Forum European Neuroscience – 07-11 July 2018 in Berlin, Germany

02.05.2018 | Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

Unique scope of UV LED technologies and applications presented in Berlin: ICULTA-2018

12.04.2018 | Event News

 
Latest News

Research reveals how order first appears in liquid crystals

23.05.2018 | Life Sciences

Space-like gravity weakens biochemical signals in muscle formation

23.05.2018 | Life Sciences

NIST puts the optical microscope under the microscope to achieve atomic accuracy

23.05.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>