All posts tagged: Earth Science

Slow orbital wobbles drove drastic climate swings on Earth

Slow orbital wobbles drove drastic climate swings on Earth

Published by Jenni Sidey

Climate can change fast, even when the planet looks stable. Earth has flipped into new patterns within decades in the past. During the last Ice Age, Greenland warmed by as much as 16°C over short spans. The North Atlantic also saw repeated iceberg surges. Scientists call these abrupt jumps Dansgaard–Oeschger and Heinrich events. For years, many researchers tied those rapid swings to ice sheets. That link made sense in an icy world. It also left a major puzzle. How could climate lurch on thousand-year timescales during hot “greenhouse” periods with little or no polar ice? An international team now offers a strong answer. Professor Chengshan Wang of the China University of Geosciences (Beijing) led the work with collaborators in Belgium, Austria, and China. Paleoclimatologist Michael Wagreich of the University of Vienna was among the co-authors. The group reports that Earth’s orbital wobble; not ice sheets; can trigger millennial-scale climate cycles in an ice-free world. Their study appeared in Nature Communications. Spatial and temporal distribution of sedimentary records displaying millennial-scale climate cycles throughout the Mesozoic and …

Tectonic research finds that Earth has six continents not seven

Tectonic research finds that Earth has six continents not seven

Published by Jenni Sidey

Memorizing seven continents feels settled, like learning the alphabet. A new study argues the ground rules are less tidy. The work comes from the University of Derby, led by Dr. Jordan Phethean. His team says Europe and North America may not be as cleanly separated as most maps suggest. The focus is the North Atlantic, where the Mid-Atlantic Ridge marks active stretching. Many textbooks treat that ridge as the scar of a breakup that happened long ago. Phethean’s group argues the separation is not finished. In their framing, the North American and Eurasian plates are still connected in ways that matter. “The North American and Eurasian tectonic plates have not yet actually broken apart, as is traditionally thought to have happened 52 million years ago,” Dr. Phethean said. Bathymetry map of the Northwest Atlantic. Overlain is a tectonic overview of the major terranes, continental blocks, and cratons colour-coded by age. The extinct MORs and FZs. Previous interpretations of continental-ocean boundaries are also displayed. (CREDIT: Gondwana Research) Iceland sits at the center of the debate. The …

Scientists discover onion-like layering in Earth’s inner core

Scientists discover onion-like layering in Earth’s inner core

Published by Jenni Sidey

Earth’s inner core has long challenged researchers because seismic waves do not move through it uniformly. Compressional waves generated by earthquakes travel roughly 3 to 4 percent faster along Earth’s rotation axis than they do across the equator. This directional difference, called seismic anisotropy, also varies with depth. Near the outer boundary of the inner core, anisotropy is relatively weak, typically around 2 percent or less. Deeper toward the center, the effect becomes much stronger, rising to about 4 to 6 percent. Understanding why this directional behavior intensifies with depth remains a major problem in Earth science. Two leading explanations have been proposed. One argues that the shapes of grains or inclusions inside the core become aligned, a mechanism known as shape preferred orientation. The other points to lattice preferred orientation, in which the crystal structures themselves line up as the material undergoes deformation. An overview of the experimental setup at DESY in Hamburg reveals the vacuum chamber housing the high-temperature diamond anvil cell: The cell’s orange colour comes from the light it emits at …

Ancient salt reveals a clear view of Earth’s atmosphere from 1.4 billion-years-ago

Ancient salt reveals a clear view of Earth’s atmosphere from 1.4 billion-years-ago

Published by Jenni Sidey

More than a billion years ago, a shallow basin in what is now northern Ontario held a subtropical lake. The setting likely resembled modern Death Valley, where heat drives evaporation and leaves salt behind. As that ancient lake dried, crystals of halite formed. Tiny pockets of brine and air became trapped inside the salt. Those pockets sealed a direct sample of Earth’s atmosphere and preserved it for about 1.4 billion years. Researchers at Rensselaer Polytechnic Institute have now opened that archive. The team was led by graduate student Justin Park and guided by geology professor Morgan Schaller. By analyzing gases trapped inside the halite, they extended direct measurements of Earth’s atmosphere far deeper into the past than ever before. Their work appears in Proceedings of the National Academy of Sciences. The period they studied sits within the Mesoproterozoic eon, a stretch of time from about 1.8 to 0.8 billion years ago. Life then was simple. Bacteria dominated ecosystems. Red algae had only begun to appear. Animals and land plants were still hundreds of millions of …

Earth’s core is leaking vast amounts of gold through the mantle, study finds

Earth’s core is leaking vast amounts of gold through the mantle, study finds

Published by Jenni Sidey

Researchers at Göttingen University have uncovered new evidence that some of Earth’s most precious metals began their journey far deeper than once thought. Working with volcanic rocks from ocean islands, the team shows that gold and related metals can leak from Earth’s core, move through the mantle, and eventually reach the crust. The study, published in Nature, was led by geochemists Nils Messling and Matthias Willbold. Their work focuses on tiny chemical differences locked inside volcanic rocks formed far below the surface. These differences help trace where the material came from and how it moved through the planet. “When the first results came in, we realized that we had literally struck gold!” Messling said. “Our data confirmed that material from the core, including gold and other precious metals, is leaking into the Earth’s mantle above.” Researchers from Göttingen found tiny traces of the precious metal Ruthenium with an anomalous isotopic composition in lavas from Hawaii. The new findings prove that the Earth’s core is leaking metallic material, including gold and other precious metals. (CREDIT: United …

Record-breaking heatwaves will persist for 1,000 years, study finds

Record-breaking heatwaves will persist for 1,000 years, study finds

Published by Jenni Sidey

Reaching net zero carbon emissions will not bring quick relief from extreme heat. New research shows that once the world stops adding carbon dioxide, dangerous heatwaves will still come often and last longer, not for decades but for at least 1,000 years. The study, published in Environmental Research: Climate, looked beyond the usual short-term forecasts. It asked what happens after emissions fall to zero and the climate settles. The answer is blunt. Net zero is vital, but it does not switch the climate back to normal. Heatwaves were measured as runs of at least three days above the hottest 10 percent for a given time of year, using 1850 to 1900 as the baseline. By that yardstick, extreme heat has already grown across most regions since the 1950s. Human-driven warming is the main cause, not natural swings in weather. Here is the core result. The later the world reaches net zero, the worse heatwaves become, and the difference never disappears. Waiting even five years adds lasting harm. Time series of a) annual atmospheric carbon dioxide …