![]() ![]() “ It was a beautiful morning in Manhattan, when my colleague Ulrika passed me this stone and asked if I need more type IaB diamonds. Tingting Gu) from GIA hadn't given it a second glance. In the most recent issue of Nature Geoscience ( ), by persevering hard work and a little bit of luck, scientists made some exceptional discoveries in a 1.5 ct gem quality diamond, which could otherwise end up in someone's engagement ring if a scientist (Dr. Therefore, although an inclusion in a diamond can be a concern for its clarity and reduce its commercial value, the geological story behind the harbored crystal endows them a unique virtue allowing us to interpret the invisible interior of the Earth. As a chemically inert vessel, diamond can envelop fragments of other minerals when they were in the deep Earth and, amazingly, protect them from chemical modifications with their surroundings and preserve their original structures when they formed under an extreme pressure inside the Earth. That’s why inclusions in diamonds are so important. However, over a long geological time, most of the geological signatures of these materials from deep Earth has been overwritten, and the chemical information of the rocks from the deep interior have been lost via their interactions with the surroundings. How can we obtain the rocks in a region where drilling is impossible? Luckily, the interior of our Earth is dynamic: the solid body is moving, bringing materials from deep to its surface. The ultimate solution to these questions is to collect direct samples from below the transition zone or ca. The different stories revealed by geophysics and geochemistry cast fundamental debates on the inner work of Earth: whether the materials at this 660 km discontinuity are blocked from mixing or penetrate through this region? More importantly, how do volatiles, such as water, cross the upper mantle through the transition zone and into the lower mantle boundary if there is a block there? However, whether the chemical composition at this boundary changes abruptly or stays the same has long been a matter of debate.Īlthough geodynamic models predict that parts of Earth’s upper and lower mantle should be mixed and stirred together, geochemical analyses of the basaltic products of mantle melting in the upper mantle display inconsistent signature with that from the region believed to represent the lower mantle, which means the upper and lower mantle could be chemically distinct. Above the boundary, the Earth is made up of crust, upper mantle and transition zone, which connect with the biosphere and atmosphere while below the boundary, the rocks behave like flows in the lower mantle that encircles Earth’s core under extreme pressure and temperature. ![]() This discontinuity has been defined as the boundary between Earth’s lower and upper mantle. Similarly, scientists may understand the components that compose Earth's interior by "listening" how seismic waves move through different materials at varying depths.įrom seismic investigations made over the past few decades, scientists learned that a global discontinuity exists at a depth of around 660 km below the surface. The process is comparable to having an ultrasound examination at a medical facility: 3D images of the biological structure are created by converting the various sound wave speeds as they pass through the body. Unfortunately, we can't view the enigmatic inner realm directly and scientists apply seismic waves as an indirect approach to probe the inner structures of the invisible deep Earth. Beneath the gorgeous landscape sculpted by Earth’s processes, scientists are curious about what is happening thousands of kilometers deeper in the Earth. Spinning in a vast cosmos, our planet is unique with its blue color covered by liquid water on its surface. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |