England's southwestern shore is renowned for the nearly continuous 185-million-year record of Earth's history exposed in its sensational seacliffs, which record one of the world's best stratigraphic sequences from the Mesozoic Era.
Twenty-seven years ago this month, the calm in central Luzon, the largest and most populous island in the Philippines, turned to chaos. On June 15, 1991, Mount Pinatubo disgorged 5 cubic kilometers of material over a few hours, and ash clouds soared 35 kilometers into the atmosphere. The substantial eruption — the second largest of the 20th century — burned itself into memories and history books.
Although chromium is a metal, it does not occur naturally in metallic form. Chromium can be found in many minerals, but the only economically significant chromium-bearing mineral is chromite. Chromite has been mined from four different deposit types: stratiform chromite, podiform chromite, placer chromite, and laterite deposits. Most of the world’s resources, however, are located in stratiform chromite deposits, such as the Bushveld Complex in South Africa. The economic potential of chromite resources depends on the thickness and continuity of the deposit and on the grade of the ore. Many of the major stratiform chromite deposits also contain economic levels of platinum, palladium, rhodium, osmium, iridium and ruthenium.
In July 2016, a team of scientists came upon a surprise 1,660 meters beneath the ocean’s surface near the Galápagos Islands: a clutch of yellow eggs, laid by a Pacific white skate, a cousin of rays and sharks. It was not the eggs themselves that surprised the team, but where they were found: near a volcanic hydrothermal vent. The large number of eggs at the site led the team to suggest that the skate was likely using the vent’s heat to incubate the eggs.
In 2017, astronomers discovered seven planets orbiting a star dubbed TRAPPIST-1, a faint red dwarf 40 light-years from Earth and only 9 percent as bright as our sun. The Earth-like qualities of these planets made headlines: they are of similar sizes to our planet, and their orbits fall within TRAPPIST-1’s habitable zone — two characteristics that scientists think are important for life to exist on a planet. Researchers now report that the TRAPPIST-1 planets have even more traits in common with Earth: they are likely rocky, and they may have surface water that exists as liquid, ice and vapor.
Far beneath the ocean’s surface, puzzling deposits from huge submarine landslides can be found amid expanses of nearly flat ocean floor. Without steep terrain, what causes these megaslides? In a new study, scientists who delved into deep-sea drilling records report a potential trigger for one such slide off the coast of northwest Africa: diatom ooze.
What does a total solar eclipse here on Earth have to do with studying life on Mars? The answer lies nearly 25 kilometers above Earth’s surface in the stratosphere, where the August 2017 eclipse offered researchers a rare opportunity to mimic conditions on the Red Planet.
Rafting down the Main Salmon River, which courses north and then west across northern Idaho, takes you by Precambrian metamorphics and the granites of the Idaho Batholith. Six to eight days later, your trip concludes as you float past what was once the edge of North America, and over former island arcs sutured onto the continent during the Mesozoic.
Since 2005, more than two dozen confirmed fatalities in California and Oregon have been caused by so-called sneaker waves, which surge far ashore with little warning, sometimes catching beachgoers by surprise. Most beaches in the Pacific Northwest and California have posted signs warning visitors of the hazard, but few scientific studies have been done on sneaker waves and, currently, there is no consensus on their definition or origin.
01 Jun 2018
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