Phys.org September 28, 2024 The Pacific large low-shear-velocity province (LLSVP) hosts multiple internal anomalies, including a notable gap between the central and eastern Pacific. The cause of the structural gap remains unconstrained. An international team of researchers (USA – University of Maryland, Canada) used a dense set of SS precursors (seismic waves) identify an anomalously thick mantle transition zone east of the East Pacific Rise directly above this structural gap. The area of the thickened transition zone exhibited faster-than-average velocities according to recent tomographic images, suggesting perturbed post olivine phase boundaries shifting in response to lowered temperatures. The researchers attributed […]
Tag Archives: Earth science
Scientists discover a vast, salty groundwater system under the Antarctica ice sheet
Phys.org May 6, 2022 West Antarctic was an ocean before it was an ice sheet. So the bedrock below the ice sheet is covered with a thick layer of sediments. A team of researchers in the US (Colorado Schools of Mines, Scripps Institution of Oceanography) has found a huge amount of groundwater, including saltwater from the ocean in the thick layer of sediments. They suggested that there is a column of water about 220 to 820 meters (700 to 2,700 feet) deep. They estimated that most of this salty water arrived in the past 10,000 years, based on how much […]
How to look thousands of kilometers deep into the Earth
Phys.org February 21, 2022 To understand how Earth has cooled and produced a solid mantle and crust, we need to know the physical properties of molten rocks at extreme pressure. An international team of researchers (Germany, UK) used the brightness of reflection from a multicolor laser to measure the refractive index of SiO2 glass and the path length of the laser inside the sample at pressures of up to 110 gigapascals, pressures similar to that at the depth of more than 2000 km in the Earth. These measurements yielded the refractive index of SiO2 glass and provided key information to […]
Climate has shifted the axis of the Earth, study finds
Science Daily April 25, 2021 Generally, polar motion is caused by changes in the hydrosphere, atmosphere, oceans, or solid Earth. However, short‐term observational records of key information in the hydrosphere limit a better understanding of new polar drift in the 1990s. An international team of researchers (China, Denmark) has introduced a novel approach to quantify the contribution from changes in terrestrial water storage by comparing its drift path under two different scenarios. One scenario assumes that the terrestrial water storage change throughout the entire study period (1981–2020) is similar to that observed recently (2002–2020). The second scenario assumes that it […]