Oceans of water deep inside the earth
What do they mean?
Published: 4 October 2014 (GMT+10)
News reports of “oceans of water locked 400 miles inside Earth” have caught people’s imagination, arousing mental pictures of water slopping around in vast underground reservoirs. One report said “Massive ‘ocean’ discovered towards Earth’s core.”1 Not so vivid was the title of the relevant paper in the journal Science—“Dehydration melting at the top of the lower mantle.”2
The transition zone extends from 410 to 660 km below the surface—the upper mantle sits above it, and the lower below (figure 1).
Paper co-author Steve Jacobsen5 has been experimenting for years in his laboratory with ringwoodite (figure 2), the mineral considered to be the most abundant in the lower transition zone. He has been able to synthesize the blue, sapphire-like mineral by reacting, at high-pressure, the mineral olivine with water. Olivine is green, and abundant in the earth’s upper mantle.
Concerning ringwoodite, Jacobsen said, “It’s rock with water along the boundaries between the grains, almost as if they’re sweating.” At the depth of the transition zone, the pressure and temperature are suited to release the water from the ringwoodite.
The other piece of the story was supplied by Brandon Schmandt.6 By analysing seismic waves from hundreds of earthquakes and thousands of seismic recorders, he concluded there are vast pockets of magma (molten rock) beneath the North American continent at the base of the transition zone.7
Based on these findings, the researchers suggested that the water in the ringwoodite in the transition zone had been forced out, and the rock partly melted. Jacobsen said, “Once the water is released, much of it may become trapped there in the transition zone.”
References to oceans of water under the earth raised questions in some people’s minds: is this water connected to Noah’s Flood? It is possible that there is a connection, but there are many questions that would need to be answered. And we must remember that descriptions of magma oceans and their mineral composition are based on circumstantial evidence.
Linking water in the mantle to the biblical Flood has been proposed before. Alex Williams in the article Drowned from below8 suggested that water from minerals in the earth’s mantle may have been the source for some of the water of Noah’s Flood. How that would work would depend on where Flood rocks begin within the geological record, and that is still debated among creation geologists.
In an article in Journal of Creation, geologist Max Hunter advocated that the pre-Flood boundary is towards the base of the earth’s transition zone (See Pre-Flood boundary).9 He proposed that decompression of the mantle initiated mantle melting, magma generation, and the release of volatiles, including copious volumes of water, which came to the surface during the Flood. It would also mean that the Flood was an enormous planetary cataclysm.
One way the water could be released from the mantle is for the rocks to undergo a change in mineral structure during Noah’s Flood. Such changes in ringwoodite could release water, and this would rise through the mantle with the magma and be expelled onto the surface through volcanic eruptions. There is much evidence for abundant volcanic eruptions during the Flood.10 Stephen Jacobsen also suggested that water from ringwoodite ended up in the oceans, but he envisages it taking millions of years. He said of his research, "It’s good evidence the Earth’s water came from within."
In summary, the claims of vast quantities of water within the mantle in the transition zone are entirely plausible, but we must keep in mind that they are based on interpretations of indirect evidence. It is feasible that such quantities of water represent the remains of a major planetary differentiation that occurred during the global Flood cataclysm, but there are questions and issues that would require further investigation.
Mantle mineral ringwoodite found in diamond
In March 2014 journal Nature reported a diamond from Brazil that contained a small speck of the mineral ringwoodite.12 The significance of the find stems from the idea that diamonds are blasted explosively from deep inside the earth to the surface in vertical volcanic tubes called kimberlite pipes (this would have been early during the catastrophe of Noah’s Flood). The explosive eruptions ‘sample’ the rocks in the mantle and enclosed the ringwoodite inclusion in the diamond.
Based on theoretical calculations it has long been speculated that ringwoodite exists in the mantle. Scientists have been able to make ringwoodite in the laboratory by combining the mineral olivine with water under high temperatures and pressures. The mineral has also been found in meteorites. However, the ringwoodite in this diamond is the first time that the mineral from the mantle has been found in on the surface.
Ringwoodite contains 1.5% water, not in the form of a liquid but as hydroxide ions (particles with a negative charge consisting of one oxygen and one hydrogen atom). Lead author of the Nature paper, Graham Pearson, a geochemist at the University of Alberta in Canada said, “It’s actually the confirmation that there is a very, very large amount of water that’s trapped in a really distinct layer in the deep Earth.”
References and notes
- Coghlan, A., Massive ‘ocean’ discovered towards Earth’s core, www.newscientist.com/article/dn25723-massive-ocean-discovered-towards-earths-core.html#.U6OltkDFDNn; 12 June 2014. Return to text.
- Schmandt, B., Jacobsen, S.D., Becker, T.W., Liu, Z., and Dueker, K.G., Dehydration melting at the top of the lower mantle, Science 344(6189):1265–1268, 13 June 2014; DOI: 10.1126/science.1253358; www.sciencemag.org/content/344/6189/1265.abstract Return to text.
- Bergeron, L., Deep Waters, New Scientist 155(2097):22–26, August 30, 1997. Return to text.
- Fellman, M., New Evidence for Oceans of Water Deep in the Earth: Water bound in mantle rock alters our view of the Earth’s composition, www.northwestern.edu/newscenter/stories/2014/06/new-evidence-for-oceans-of-water-deep-in-the-earth.html 12 June 2014. Return to text.
- An associate professor of Earth and planetary sciences at Northwestern’s Weinberg College of Arts and Sciences. Return to text.
- An assistant professor of geophysics at the University of New Mexico. Return to text.
- The ‘image’ produced from such an analysis would be a bit like the image from an x-ray, and would require skill and experience to interpret, and could be ambiguous. Return to text.
- Williams, A., Drowned from below, Creation 22(3):52–53, 2000, creation.com/drowned-from-below. Return to text.
- Hunter, M.J., The pre-Flood/Flood boundary at the base of the earth’s transition zone, Journal of Creation 14(1):60–74, 2000. Return to text.
- Walker, T., Volcanoes shaped our planet: fiery catastrophe greater in the past, Creation 34(2):20–23, 2012; creation.com/volcanoes. Return to text.
- Bui, Hoai-Tran, Water discovered deep beneath Earth’s surface, www.usatoday.com/story/news/nation/2014/06/12/water-earth-reservoir-science-geology-magma-mantle/10368943/; 12 June 2014. Return to text.
- Oksin, B., Rare Diamond Confirms That Earth’s Mantle Holds an Ocean’s Worth of Water: The diamond contains ringwoodite, which is water-rich but only forms naturally under the extreme pressure found in Earth’s mantle, scientificamerican.com/article/rare-diamond-confirms-that-earths-mantle-holds-an-oceans-worth-of-water/; 12 March 2014. Nature paper was published on the same day. Return to text.