Preston North End have signed midfielder Josh Harrop from Manchester United on a four-year contract, the English Championship team said on Friday.Harrop, 21, was the top scorer for United’s reserve team with 10 goals in 25 appearances last season and made a memorable senior debut, scoring the opener in United’s 2-0 win over Crystal Palace on the final day of the 2016-17 league campaign.”It’s a new start for me to get things going in my career and I’m buzzing to get playing and to make an impact in the team,” Harrop said on Preston’s official website. (www.pnefc.net)”Hopefully I can achieve my aims and ambitions that I have set myself by coming here and that’s to get promoted with Preston North End and help the club get as high as we can.”Harrop is Preston’s third signing in the current transfer window as they recruited striker Sean Maguire and goalkeeper Declan Rudd earlier this month.
Citation: Diamond inclusions suggest free flowing water at boundary between upper and lower mantle (2018, March 9) retrieved 18 August 2019 from https://phys.org/news/2018-03-diamond-inclusions-free-boundary-upper.html More information: O. Tschauner et al. Ice-VII inclusions in diamonds: Evidence for aqueous fluid in Earth’s deep mantle, Science (2018). DOI: 10.1126/science.aao3030AbstractWater-rich regions in Earth’s deeper mantle are suspected to play a key role in the global water budget and the mobility of heat-generating elements. We show that ice-VII occurs as inclusions in natural diamond and serves as an indicator for such water-rich regions. Ice-VII, the residue of aqueous fluid present during growth of diamond, crystallizes upon ascent of the host diamonds but remains at pressures as high as 24 gigapascals; it is now recognized as a mineral by the International Mineralogical Association. In particular, ice-VII in diamonds points toward fluid-rich locations in the upper transition zone and around the 660-kilometer boundary.Press release A team of researchers from the U.S., China and Canada has found evidence in diamonds of free-flowing water in the boundary between Earth’s upper and lower mantle. In their paper published in the journal Science, the group describes analyzing inclusions in diamonds spewed from volcanoes and what they found. This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. The researchers were looking for molecular forms of carbon dioxide as part of carbon cycling in the Earth’s mantle when they came across evidence of something else. They had collected diamonds spewed from volcanoes (or pushed to the surface by other geologic activity) in Zaire, China, Sierra Leone and other locations in southern Africa, and were studying them by bouncing X-rays off the diamonds’ inclusions, when they came across samples of ice VII—a form of ice that does not occur naturally at the surface. The find was significant, because ice VII forms at very high pressure—approximately the amount of pressure found at depths of 610 to 800 kilometers beneath the Earth’s surface. This, the team notes, suggests that water must have been freely flowing at such depths to form the inclusions they observed. Such depths, they further note, fall into the transition zone in the mantle, a part of the Earth’s interior that is still a source of mystery.Prior research has shown that the mantle is made up mostly of hot rock under a lot of pressure. It has a lower layer, closest to the core, a transition layer, and an upper layer that eventually meets the crust. Prior research has also shown that the upper mantle has some water, which hints that there may also be water in the transition layer. The diamonds the researchers were studying would have been encased in liquid somewhere in the transition zone. The high temperatures there would not have allowed them to crystallize, however—it was only as they moved to the surface that crystallization would have occurred. The high pressure would have been maintained inside the diamond, but the temperature would have dropped dramatically. The idea of water moving around in the transition layer is intriguing, the team reports, because it has implications for tectonic plate shifting. Using Argonne’s Advanced Photon Source, researchers identified a form of water known as Ice-VII, which was trapped within diamonds that crystallized deep in the Earth’s mantle. Credit: University of Chicago.