Water cooling for the Earth’s crust

Seawater penetrates much deeper than previously thought

Date:
November 21, 2017
Source:
Helmholtz Centre for Ocean Research Kiel (GEOMAR)
Summary:
How deep can seawater penetrate through cracks and fissures into the seafloor? By applying a new analysis method, an international team of researchers has now discovered that the water can penetrate to depths of more than 10 kilometers below the seafloor. This result suggests a stronger cooling effect on the hot mantle.

The hydrothermal circulation changes the ocean crust and increases the Chlorine (CL) concentration of the rocks by incorporation of sea water. The magma takes up parts of this crust leading to an increase of chlorine of the magma. If the magma erupts at the sea floor, basalt lava is formed that we sampled and investigated in detail.
Credit: GEOMAR

How deep can seawater penetrate through cracks and fissures into the seafloor? By applying a new analysis method, an international team of researchers has now discovered that the water can penetrate to depths of more than 10 kilometers below the seafloor. This result suggests a stronger cooling effect on the hot mantle.

Hot vents in the deep sea and geysers on land document the penetration of water into the hot interior of the Earth. This happens primarily in regions where the crust breaks up and magma chambers are close to the surface, e.g. in the area of mid-ocean ridges. But how deep does the water penetrate and cool the upper part of the hot mantle? So far it has been assumed that this process only reaches depths of a few kilometres. A new analytical method, developed at GEOMAR Helmholtz Centre for Ocean Research Kiel, now shows that water penetrates much deeper into the Earth than previously thought.

“Chlorine is the key element in our investigations,” explains Dr. Froukje van der Zwan, first author of the GEOMAR study. “We were able to detect this indicator for seawater in basalt rock even in very low concentrations,” van der Zwan continues. In her PhD thesis, she developed a new method to study chlorine levels in rock samples collected at the Southern Mid-Atlantic Ridge and Gakkel Ridge in Central Arctic. In addition, a chemical analysis of selected crystals in the rocks samples also allowed the depth at which the chlorine was incorporated into the rock to be determined.

“For our analyses, we had to push the electron-beam microprobe to its limits. It is a special scanning electron microscope, to which spectrometers are attached for the quantitative analysis of major, minor and trace element concentration,” van der Zwan explains. The microprobe, as well as other necessary devices, were available at GEOMAR. Furthermore, with the results of this study, the authors were able to verify theoretical models that were developed at GEOMAR.

“So far, it has been assumed that high pressure and temperatures prevented water from penetrating below 10 kilometres,” says Prof. Dr. Colin Devey, co-author of the GEOMAR study. “We can now show that the water penetrates much deeper,” Devey continues. This finding is important for the cooling of the oceanic crust and its heat budget, as well as for the total level of volatiles in the oceanic crust, which are later subducted and recycled into the mantle.

Story Source:

Materials provided by Helmholtz Centre for Ocean Research Kiel (GEOMAR)Note: Content may be edited for style and length.


Journal Reference:

  1. Froukje M. van der Zwan, Colin W. Devey, Thor H. Hansteen, Renat R. Almeev, Nico Augustin, Matthias Frische, Karsten M. Haase, Ali Basaham, Jonathan E. Snow. Lower crustal hydrothermal circulation at slow-spreading ridges: evidence from chlorine in Arctic and South Atlantic basalt glasses and melt inclusionsContributions to Mineralogy and Petrology, 2017; 172 (11-12) DOI: 10.1007/s00410-017-1418-1

Cite This Page:

Helmholtz Centre for Ocean Research Kiel (GEOMAR). “Water cooling for the Earth’s crust: Seawater penetrates much deeper than previously thought.” ScienceDaily. ScienceDaily, 21 November 2017. <www.sciencedaily.com/releases/2017/11/171121121441.htm

  • gplus
  • pinterest

Author

Dursun Yıldız

DURSUN YILDIZ
Civil Engineer
Hydro Politics Expert

He was born in Samsun in 1958. He was graduated from İstanbul Technical University Civil Engineering Faculty in 1981. After completing his military service in 1983 he began to work in State Hydraulic Works Technical Research and Quality Control Department. While working here he participated graduate professional education and investigation programs in Holland and USA Bureu of Reclamation and US Army Corps of Engineers.

In 1998 he participated first “EU Master Education” program and later “International Affairs Proficiency” program in Ankara University European Union Research and Application Center. In 2000 he completed his MS thesis in the topic of water politics in Hacettepe University Hydropolitics and Strategy Research Center. He worked for five years as the section head and for following 10 years as department deputy head in State Hydraulic Works Technical Research and Quality Control Department. During this period he published more than 100 technical and scientific reports and papers. Then he worked as the department deputy head in State Hydraulic Works Domestic Water Supply Department and worked at the Planning and Investigation Department of the same institution and retired in 2007.

Dursun YILDIZ while working in State Hydraulic Works he lectured in the topics of water works in Gazi University Engineering and Architectural Faculty, Civil Engineering Department and water resources and hydropolitics in Hacettepe University, Hydropolitics and Strategy Research Center.

Dursun YILDIZ worked also as a executive committee member , Vice President in Turkish Chamber of Civil Engineers and Vice President of the Union of Chambers of Turkish Engineers and Architects . He worked in execution committee of “Water Politics Congress” held by the Civil Engineers Chamber in several times.

Dursun YILDIZ, experienced in water management, water development ,hydraulic research and consultancy for 30 years, wrote 15 books (Water Report,Water Problems in the Mediterranean Basin and Turkey,Strategical İmportance and Water Related İssues in Eastern Meditterranean Water Security 2050, etc.) and besides published several papers and technical reports in the topics of water engineering,water development,hydraulic research and hydro-politics in national and international periodicals.
He has awarded Successful Water Resarcher Prize of Year of 2008 by Agriculturers Associations of Türkiye .He was also awarded continuously success on water research prize of 2016 by Central Union of Irrigation Cooperatives of Turkey.

He is a member of Scientific Committee of Turkish Foundation for Combating Soil Erosion (TEMA). He is now the director of an NGO called Hydropolitics Association, and runs a company, Ada Hydro-Energy, Strategy & Engineering Consultancy Co.
He is head of Ada Hydro-Energy , Strategy & Engineering Consultancy Co. Since 2007.He is president of Hydropolitics Association.