WorldWide Drilling Resource

30 APRIL 2021 WorldWide Drilling Resource ® Special Diamonds and a Unique Laser Reveal Geological Past Adapted from Information by the University of Alberta and the Australian National University Understanding our planet’s core and mantle is a challenging task. Scientists don’t have core samples, we can’t travel there, and we aren’t able to drill down and take a look, so they must rely on seismic data as well as geological evidence. Most of the existing geological data about the planet’s composition is based on information gathered from basalt rock which has made its way from the mantle to the surface, but it doesn't tell the full story; the rock goes through significant changes on its geological journey to the surface. Diamonds, on the other hand, are the hardest, most inde- structible natural substance on our planet. So when researchers from the University of Alberta and the Australian National University (ANU) were given the opportunity to analyze super deep diamonds, likely from about 250-400 miles belowground, recovered from the Juina area of Brazil, they didn’t know what to expect. Dr. Suzette Timmerman, who was recently awarded her Ph.D. from the Australian National University, and a postdoctoral researcher in the Department of Earth and Atmospheric Sciences at the University of Alberta, used a special laser tool to shed some light on what is at the center of our planet. The one-of-a-kind tool, uses lasers to carve tiny pieces off the incredibly durable diamonds to study. "For the first time ever, we've been able to examine helium isotopes trapped in fluid inclu- sions in super deep diamonds," explained Dr. Timmerman, lead author of the paper, Primordial and recycled helium isotope signatures in the mantle transition zone . "These isotopes can tell us new information about the structure of the earth, advancing our understanding of the evolution of our planet." They found high Helium-3 (3He) and Helium-4 (4He) ratios in the super deep diamonds which support the existence of a theorized, ancient primordial reservoir of molten rock which has been around since, or very soon after, the earth's formation nearly 4.5 billion years ago - and where it might be located. "Previous studies have argued about whether such a reservoir exists and whether it would be found in the lower mantle or upper mantle," said Timmerman. "Our super deep diamonds confirm this reservoir exists and narrows down that it must be . . . located somewhere below a depth of [around 250 miles] in the transition zone or lower mantle - giving us a clearer picture of the structure of earth." Since 3He is a stable isotope, meaning it doesn’t decay into other elements, the discovery of 3He indicates the existence of a primordial reservoir. According to Dr. Timmerman, “All 3He inside the earth has been there since the beginning of time." Dr. Timmerman, along with coauthor Dr. Lynton Jaques, said these diamonds offer a unique glimpse inside the earth. "There are only a few places in the world where these super deep diamonds are found, but they provide a lot of information about the deeper parts of the earth's mantle, which we never otherwise see," Dr. Jaques said. "Diamonds form perfect capsules, so they retain the exact chemistry and the isotope composition of material from the part of the earth where they formed. These diamonds in particular are some of our deepest direct samples of the earth. They allow us to see some original material from the formation of the earth, that doesn't seem to have changed much over the past four billion years." Although scientists, including researchers at the ANU, have used high-pressure experiments to replicate the unique conditions in the earth's mantle, these dia- monds offer a natural sample. "Super deep diamonds are very special," said Timmerman, "They're our only direct window into the deeper parts of earth." Despite the breakthrough, there are still plenty of unanswered questions about this ancient reservoir. "People had long thought there was this high Helium-3 patch in the mantle, and we can say a little bit more about it now, but we still don't know how big it is, or how evenly distributed across the deeper parts of the mantle it is," said Dr. Timmerman. Dr. Timmerman will continue her research as a Banting Fellow at the University of Alberta, focusing her studies on super deep diamonds by exploring the age of these unique rocks and what they can tell us about our planet's carbon cycle. Editor’s Note: In between our print issues, the WWDR Team prepares an electronic newsletter called E-News Flash . This newsletter is filled with articles not included in our print issue. Based on readershi p, this was the most popular article of the month. Get in on the action and subscribe today at: ENV Photo of Dr. Timmerman by Gareth Davies courtesy of the University of Alberta. 302-684-3197 FAX: 302-384-0643 142 Broadkill Rd. • Milton, DE 19968 email : Manufacturers of Slotted & Perforated Pipe ranging from ½” to 24” diameter Atlantic Screen & Mfg., Inc. • Well Rehab. Products • Manholes • Bentonite • Filter Sock • Inline Chemical Mixers • Sampling Bailers • Clear PVC Pipe • Locking Caps