Taxonomy term

mineral

In feats of tectonic strength, grain size matters

Plate tectonics involves some of the most powerful forces on Earth, but the lithosphere, of which the plates are made, is not infinitely strong: Weaknesses in the lithosphere allow it to break apart and form plate boundaries. Determining the strength of tectonic plates based on field observations has proved tricky, however, due to the sheer scale of plates, while experiments and calculations in the lab on olivine — the main mineral that makes up the lithosphere — have depicted plates as misleadingly strong. In a new lab-based study, researchers have taken a novel approach to testing olivine’s strength, and the results fit existing models of plate tectonics better than previous efforts.

04 Jan 2018

Minerals deformed by meteorites reveal age of impact

Researchers have discovered a new way to determine when a meteorite hit Earth, a technique that could not only help scientists date ancient meteorite strikes but also determine when planetary crusts first formed.

03 Oct 2017

Ups and downs of potassium feldspar may play role in clouds and climate

For water vapor in the atmosphere to transform into icy, cloud-forming droplets, it needs a seed around which to condense, such as aerosols, sea salt or bacteria. One of the most effective seeds is mineral dust, in particular potassium feldspar, one of the main ingredients in granite. New research tracking fluxes of potassium feldspar in the atmosphere through geologic time is shedding light on the long-term importance of the mineral in cloud formation and climate feedback cycles.

30 May 2017

Investigating erionite, asbestos' more carcinogenic cousin

Asbestos is notorious for causing lung cancer and other respiratory diseases, but it’s not the only type of fibrous mineral that affects human health. In the mid-1970s, erionite was linked to the unprecedented high mortality rate from mesothelioma in villages in central Turkey where volcanic tuff had been used as a building material for centuries. Like asbestos, erionite can occur as long thin fibers that, when inhaled, can persist in lung tissue for decades. New research looking at associations of iron with erionite is helping pathologists better understand why embedded erionite fibers sometimes lead to lung cancer.

08 May 2017

Isotopes could reveal ancient American turquoise trade

For centuries before the arrival of Europeans, turquoise was prized among pre-Hispanic cultures of North America. Caches of the distinctive, creamy-blue-green mineral have been unearthed in crypts and other ritually significant structures in what are now the southwestern United States and northern Mexico. Farther south, in Mesoamerica, archaeologists have found elaborate mosaic masks and ornamentation made of turquoise pieces. Despite multiple anthropological and historical hints, identifying where the turquoise used by different civilizations came from has proven difficult. But in a recent study, scientists have described a geochemical fingerprinting technique that may help parse the geographic origins of turquoise specimens and illuminate trade routes in ancient America.
 
09 Nov 2015

Stalled slabs sometimes stopped by mineral strengthening

Subduction of tectonic plates into the mantle functions as an eons-long recycling system for Earth’s crust and lithosphere. But in some subduction zones, the downgoing slabs seem to get stuck at depths of about 1,000 kilometers, held up by some unseen barrier on their journey deeper into the lower mantle. Now, scientists propose that this barrier might be related to high-pressure-induced strengthening of minerals in the rocks surrounding subducting slabs at these depths.
09 Aug 2015

Benchmarks: July 22,1960: Mineral discovery ends Meteor Crater debate

In 1923, Daniel Moreau Barringer stood on the edge of a vast bowl-shaped depression in the Arizona desert, watching a drill rig bore into the floor of the crater. Barringer had spent more than two decades exploring the massive hole, which lies on the Colorado Plateau 65 kilometers east of Flagstaff, Ariz. And although he had sunk dozens of drill holes, collected scores of samples, and carefully mapped the piles of talus that draped its concave walls, Barringer still hadn’t found what he was looking for, and he was getting nervous.
 
22 Jul 2015

Earth's most abundant mineral finally gets a name

An elusive, high-density form of magnesium iron silicate, long known colloquially as “silicate perovskite,” now officially bears the name “bridgmanite,” after the father of high-pressure experiments, Nobel laureate Percy W. Bridgman.

 
03 Jun 2015

Down to Earth With: Mineralogist George W. Robinson

Many geologists understand the joyous feeling of coming across a beautiful rock in the field; George W. Robinson, who began collecting minerals at age 9, has had a lifetime full of such moments. After delving deeper into his early avocation as a teenager, he received his doctorate in mineralogy from Queen’s University in Kingston, Ontario, in 1979. He has worked as a high school earth science teacher, field collector, mineral dealer, museum curator and professor — all occupations that shared a common focus: a love of minerals.

 
19 Feb 2015

Asbestos found in Nevada and Arizona: Roadblock and potential health hazard?

The discovery of a previously unknown type of asbestos-forming geologic environment means asbestos may be more widespread than thought. But is it a health hazard?

29 Jan 2015

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