Ringwoodite Holds the Majority of Earth’s Water Underground

Blue Ringwoodite - Wiki CommonsFollowing up on theories that ringwoodite minerals deep within the Earth’s mantle may contain water, a BBC News report says researchers have provided the first direct evidence of this theory.

Diamonds, brought to the Earth’s surface in violent eruptions of deep volcanic rocks called kimberlites, provide a tantalising window into the deep Earth.

A research team led by Prof Graham Pearson of the University of Alberta, Canada, studied a diamond from a 100-million-year-old kimberlite found in Juina, Brazil, as part of a wider project.

They noticed that it contained a mineral, ringwoodite, that is only thought to form between 410km and 660km beneath the Earth’s surface, showing just how deep some diamonds originate.

While ringwoodite has previously been found in meteorites, this is the first time a terrestrial ringwoodite has been seen. But more extraordinarily, the researchers found that the mineral contains about 1% water.

According to the news report, this discovery is important because it solves a 25-tyear-old controversy about deep Earth being wet, dry, or wet in patches. The finding implies that the interior of the planet may store several times the water in the oceans, and demonstrates how hydrogen plays a critical role in the interior processes of the planet, and possibly other planets including Mars.

For more information on ringwoodite:

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Cascadia Subduction Zone: Unprepared and Liquefaction

Call me paranoid, but when I see a 7.8 earthquake in Indonesia, and the news recalls the 8.9 magnitude earthquake that triggered the deadliest tsunami in history in 2004 killing more than 200,000 people, I’m reminded that we live in the shake zone of earthquakes and tsunamis, the Cascadia Subduction Zone. It doesn’t help when The New Yorker Magazine tells us that the “Really Big One” is coming and we’ll be able to surf to Idaho soon.

Last year, OPB-TV won awards for their “Unprepared” television series and documentary on the historical “big one” coming to the Pacific Northwest. It led to discussions around the state of Oregon involving geologists, seismologists, and area experts, all asking if we are prepared and what are we going to do or not do about it. They talked about the state of our bridges, schools, and the impact of liquefaction on our ports, home to fuel tanks, some almost 100 years old, that could rupture, dump into our precious waterways, and burn for ages. It was a wake-up call for all of us.

As a rock lover, I started questioning the ground under my feet. According to FEMA’s Earthquake Risk and Cascadia Region Earthquake Workgroup (CREW) and their educational Cascadia Subduction Zone Earthquakes 9.0 Magnitude Scenario (PDF), while I’m personally outside of the tsunami zone, besides being cut off from the rest of the world, the thing to fear most is: Liquefaction.

Tilted Victorian Home in San Francisco due to liquefaction - Photograph by G.K. Gilbert of the U.S. Geological Survey

Liquefaction is the process in which soil, often thought to be firm and solid, is “reduced” by earthquake shaking. While most commonly associated with saturated soils, liquefaction occurs in dry soils where there is space between the particles. Take a jar and fill it full of flour or grains. Tap it against the counter and you will see the level drop. Depending upon the space and shape of the grains, it might drop a little or a lot. That’s liquefaction in action. Continue reading “Cascadia Subduction Zone: Unprepared and Liquefaction”

Scientists Release List of the Rarest Earth Minerals

BBC News Science and Environment column reported that scientists have catalogued the largest list ever of rare minerals. The list, published in American Mineralogist, was authored by Dr Robert Hazen, from the Carnegie Institution in Washington DC, and Prof Jesse Ausubel of The Rockefeller University, in New York, and includes more than 5,000 mineral species.

“Scientists have so far tracked down 5,000 mineral species and it turns out that fewer than a 100 constitute almost all of Earth’s crust. The rest of them are rare, but the rarest of the rare – that’s about 2,500 minerals – are only found at five places on Earth or fewer,” Dr Hazen told BBC News.

“And you ask: why study them; they seem so insignificant? But they are the key to the diversity of the Earth’s near-surface environments.

“It’s the rare minerals that tell us so much about how Earth differs from the Moon, from Mars, from Mercury, where the same common minerals exist, but it’s the rare minerals that make Earth special.”

The list includes rare examples including cobaltominite, abelsonite, fingerite, edoylerite, and the extremely rare “vampire-like minerals” that fall apart immediate when wet or the sun shines on them: edoylerite, metasideronatrite, and sideronatrite.

For more information:

Washington State Rocks and Minerals Exhibit at WWU in Bellingham

If you are heading north into Washington State, way far north towards the Canadian border, take time to drop by Western Washington University in Bellingham for their free and open to the public exhibit of the minerals, fossils of Washington state, reports the Bellingham Herald. The exhibit is on the ground floor and part of the first and second floors of the Environmental Studies Building.

It’s like a mini-museum, with displays that include mineral crystals, mammoth teeth and fossilized plant leaves, along with interpretive exhibits that highlight coal mining in Whatcom County and show some of the tools and equipment that scientists use to study the Earth. There’s even a seismograph and seismometer.

…Possibly the most fascinating display is a four-foot slab of sedimentary rock containing the three-toed footprint of a diatryma, a giant flightless bird from the Eocene Period, some 34 million to 56 million years ago. It was discovered in sedimentary rock that shook loose in a landslide several years ago near Racehorse Creek in the Mount Baker foothills. The slab was airlifted by helicopter to WWU.

As our members know well, Washington (as well as Oregon) is one of the most geologically dynamic areas in the world. This exhibit is designed to showcase what they are calling “Northwest Origins” going back more than 1 billion years old.

If you head up there, please let us know and consider writing a report about the exhibit for the website and newsletter.

The Strongest Mineral on Earth Found Along the Sea

Geothite by Wiki Commons.

For those working in the lapidary arts, we’ve been dazzled by the strength of the minerals and gems we find. The Washington Post announces there is something in nature stronger than diamonds and steel, and unbreakable by bullets.

Currently, the strongest natural material known is the silk of a spider. With this new research, your next tidal pool adventure along the Pacific Northwest coastline might come with a new perspective, and a new respect.

In a study set to come out this month in the Journal of the Royal Society Interface, British researchers announced that the teeth of shelled, aquatic creatures called limpets are the strongest biological material on Earth, overtaking the previous record-holder, spider silk.

The teeth, which are so small they must be examined with a microscope, are composed of very thin, tightly-packed fibers containing a hard mineral called goethite. Limpets use them to scrape food off of rocks, but lead author Asa Barber said humans can adapt the technology to build better planes, boats and dental fillings.

Testing found the mineral material in the snail-like creatures commonly found along tidal pool areas to be nearly flawless in their very thin filaments, reinforcing the structural components, and have a strength of 5 gigapascals, five times that of most spider silks.

The teeth also bested several man-made materials, including Kevlar, a synthetic fiber used to make bulletproof vests and puncture-proof tires. The amount of weight it can withstand, Barber told the BBC, can be compared to a strand of spaghetti used to hold up more than 3,300 pounds, the weight of an adult female hippopotamus.

For information on geothite, see:

Jade: Did You Know There are More Than Two Types?

The following is by Tualatin Valley Rock and Gem Club member Taylor Hunt. if you would like to contribute to our newsletter and website with articles on various rocks, minerals, and gems, please contact us.

The gemstone jadeite generally forms as a result of the plate tectonic process of subduction. Jade made from jadeite forms when supercritical fluids from subducting oceanic crust condense in the overlying man-tel wedge (the “wedge” is all the sediments swept up, piled and squeezed between the subducting oceanic plate and a continental mass), between 20 & 60 km deep in the Earth. Jadeite deposits thus mark the loca-tion of exhumed fossil subduction zones.

A new term PTG’s, plate tectonic gemstone, and jadeite is one PTG currently recognized. For various reasons most PTG’s are found in rocks or continental plates considered young to planet Earth. Most are no older than the formation of the supercontinent of Rodinia or 1,000 ma yr. Petrotectonic indicators that form deep in the Earth have the added advantage that their record is unlikely to be obliterated by erosion. Recognition of the PTG’s links modern concepts of plate tectonics to economic gemstones deposits and the ancient concepts of beauty, and may aid in exploration for new deposits.

Any mineral or stone beautiful enough to be sought, mined and sold for its beauty alone is a gemstone. The subclass of rocks and minerals that comprise gemstones—whether precious or semi-precious—has mostly been established since antiquity. Humans have sought and prized gemstones since thousands of years be-fore the science of geology was established. Because gemstones are rare by definition, the geological conditions that produce them must have been exceptional. Thus, there is a confluence of economic, aesthetic and academic interest in gemstones. Jade — specifically the variety jadeite — is the characteristic beautiful product of normal oceanic lithosphere subduction.

The following images are from Wiki Commons and Flickr contributors, used under copyright and public domain free image licenses.

Jade is a term ascribed to two different materials with similar properties, toughness, and beauty that evolved in usage and significance from toolstones for axes, choppers and hammers to one of the most highly revered gemstones in the world. As a tool, jade was employed during the Paleolithic (stone age, before 3500 BCE) but was raised to high symbolic stature as a gemstone in proto—Chinese Hongshan and Liangzhu cultures by 3500 BCE, and in the Jom’on culture of Japan by 3000 BCE, and in Central America by the Olmec of the Early Formative period by at least 1500 BCE and later in the Mayan civilization. Hard jade (jadeitite) or “ying yu” in Chinese consists predominately of pyroxene minerals, jadeite (Na,Al,Si2,O8), while soft jade (nephrite jade) “ruan yu” come from amphibole minerals of tremolite-actinolite [Ca2(Mg,Fe)5,Si8O22(OH)2]. The term jade was derived from the Spanish “piedra de yjada” (loin stone) for talismans worn by the Aztec to ease abdominal pain, but was mistranslated to the word jade. In New Zealand, nephrite jade is sometimes called greenstone and was a favorite of the Maoris. Continue reading “Jade: Did You Know There are More Than Two Types?”

Adopt-a-Mineral at the Rice Northwest Museum – Fluorite

The Rice has a great program called Adopt-a-Mineral, allowing the public to donate to the museum by adopting a rock and mineral. The following article is about one of those minerals, fluorite, available for adoption now.

Fluorite (AM 29, AM 30)

Carlo Galeani Napione named the mineral fluorite in the late 1700s. The name derives from the Latin “fleure”, meaning flow, because it is commonly used as a flux. Fluorite is a halide, in which a metal is bonded to one of the halogen elements (fluorine, chlorine, bromine, iodine).

The following images are used courtesy of Wiki Commons.

Fluorite is commonly translucent and found with a vitreous (glassy) luster. It has many colors including, green, purple, yellow, pink, brown and colorless. Its streak (color of the powdered mineral) is white. Fluorite has a hardness of ~4 and is the hardness reference species on Mohs’ scale. It is a brittle mineral, and it will fracture and break along perfect cubic and octahedral cleavage planes. Fluorite usually occurs as cubes, although it can also be found as octahedra (8-faced crystals), and rarely as dodecahedra (12-faced crystals). Sometimes these forms can be found combined in single crystals. When not seen as large crystalline specimens, fluorite is usu-ally massive, or an aggregate of very small cubes. Continue reading “Adopt-a-Mineral at the Rice Northwest Museum – Fluorite”

Mount Saint Helen’s Crystals Predict the Past

Scientific American reports that a team in England and Germany are using crystallized minerals formed in the volcano just before eruption to determine a timeline of volcanic activity, and possibly predication from a study in the May 25 issue of Science.

…the researchers report that crystals of the silicate mineral orthopyroxene from 1980 and from subsequent eruptions trace various injections of magma, as well as other chemical changes, within the bowels of the volcano.

The crystals contain concentric rings of differing chemical composition. Some orthopyroxene crystals, for instance, have a magnesium-rich core surrounded by an iron-rich rim; others have an iron-rich core and a magnesium-rich rim. Each type of crystal zonation can record the conditions of the magma reservoir from which it emerged.

“We chemically fingerprint each of those zones to determine how they formed,” says lead study author Kate Saunders, a volcanologist of the University of Bristol in England. The outer rim of an orthopyroxene crystal, she says, represents the most recent stage of crystal formation and typically grew just months before the crystal’s emergence in volcanic ejecta. That allowed the researchers to make precise estimates of when, and how, the crystals acquired their chemical forms. “Mount Saint Helens is really good—because the samples, we know exactly when they erupted,” Saunders says.

They hope that the study of these crystals will corroborate and offer insight into the historical timeline of erruptions, something researchers today can only guesstimate.

For more information, see “What’s the Point of Volcano Monitoring?” from Scientific American and “Linking Petrology and Seismology at an Active Volcano” from Science.