June 2022

Study Explains How Some Minerals Can Change Color Repeatedly

Geochemistry, Mineralogy, Minerals 8:27 PM

<p></p><table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto;"><tbody><tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgks2Nkwv60NJmNgDYj4E2OYRKjo_9Gu_gKLYxKDU-eU7rpAffaLQqyB5IimfGzzwBqcgEpxBJiAF9cLRpn34_syTxnG9ag6vbch3ffXoYs1J4uWABtjTx_HDsqZsq1AbASVwl5Cjx0N6BzwWw13VTA-fXfJFkFjjWrvglfY5mZ3k8LfTgPOAQlddmE/s1490/Study%20Explains%20How%20Some%20Minerals%20Can%20Change%20Color%20Repeatedly.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img alt="Study Explains How Some Minerals Can Change Color Repeatedly" border="0" data-original-height="790" data-original-width="1490" height="340" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgks2Nkwv60NJmNgDYj4E2OYRKjo_9Gu_gKLYxKDU-eU7rpAffaLQqyB5IimfGzzwBqcgEpxBJiAF9cLRpn34_syTxnG9ag6vbch3ffXoYs1J4uWABtjTx_HDsqZsq1AbASVwl5Cjx0N6BzwWw13VTA-fXfJFkFjjWrvglfY5mZ3k8LfTgPOAQlddmE/w640-h340/Study%20Explains%20How%20Some%20Minerals%20Can%20Change%20Color%20Repeatedly.jpg" title="Study Explains How Some Minerals Can Change Color Repeatedly" width="640" /></a></td></tr><tr><td class="tr-caption" style="text-align: center;">Study Explains How Some Minerals Can Change Color Repeatedly. Tanzanite crystals Pleochroism. Photo: Spirifer_minerals</td></tr></tbody></table><br /><p></p><p style="text-align: left;">While investigating hackmanite, a natural wonder material, researchers found that it, in addition to two other minerals, can change their color upon exposure to UV radiation repeatedly without wearing out. The results show that the inexpensive hackmanite, which is easy to synthesise, is also an excellent material because of its high durability and applicability for different purposes.<br /><br />A research group at the University of Turku, Finland, has been investigating and developing the properties of the wonder material hackmanite for almost a decade. Applications such as personal UV monitoring and X-ray imaging have been developed based on hackmanite's ability to change color.<br /><br />Hackmanite changes its color from white to purple under UV irradiation and eventually reverts back to white if no UV is present. The structural features enabling such repeated changes have so far been unclear. Now, upon investigating three natural minerals -- hackmanite, tugtupite and scapolite -- the researchers have found the answer.<br /><br />The investigated color-changing minerals are inorganic natural materials, but there are also organic compounds, hydrocarbons, that can change color reversibly due to exposure to radiation. These hydrocarbons, however, can only change color only a few times before their molecular structure breaks down. This is because the color change involves a drastic change in the structure, and undergoing this change repeatedly eventually breaks the molecule.<br /><br />"In this research, we found out for the first time that there is actually a structural change involved in the color change process as well. When the color changes, sodium atoms in the structure move relatively far away from their usual places and then return back. This can be called as structural breathing and it does not destroy the structure even if it is repeated a large number of times," reports Professor Mika Lastusaari from the Department of Chemistry at the University of Turku, Finland.<br /></p><h4 style="text-align: left;"><span style="font-family: georgia;">Researchers proved that hackmanite's ability to alternate between white and purple forms is highly repeatable</span></h4><p style="text-align: left;">According to Professor Lastusaari, the durability is due to the strong three-dimensional cage-like overall structure of these minerals, which is similar to that found in zeolites. In detergents, for example, the cage-like structure enables zeolite to remove magnesium and calcium from water by binding them tightly inside the pores of the cage.<br /></p><div style="margin: 0px auto; width: 100%;">
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</div><p><br />"In these color-changing minerals, all processes associated with the color change occur inside the pores of the zeolitic cage where the sodium and chlorine atoms reside. That is, the cage-like structure allows atomic movement inside the cage while keeping the cage itself intact. This is why minerals can change color and revert back to their original color practically indefinitely," Doctoral Researcher Sami Vuori explains.<br /><br />Previously, it has been known that scapolite changes color much faster than hackmanite, whereas tugtupite's changes are much slower.<br /><br />"Based on the results of this work, we found out that the speed of the color change correlates with the distance that the sodium atoms move. These observations are important for future material development, because now we know what is required from the host structure to allow the control and tailoring of the color change properties," comments Doctoral Researcher Hannah Byron.</p><table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto;"><tbody><tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjQLZ0ZzSP3uVdsOSnWOeeTDz1qI8A7UFmAoFRdqqefwC2P1wMBOMwEAFlpOzl2OS3jKGcHZtirvN7YI_lsoV1akhOB4J0FgVuXnVwu1WdKCXX0mC7tc8_Wz-xwNO4k7j-GCCY_LUGoKNqqt-HeAAoKJ34WdHtIno7JND__bc9HOFailkDP3tgurPgO/s1237/Scapolite%20-%20photo%20by%20Sami%20Vuori%20(1).jpg" style="margin-left: auto; margin-right: auto;"><img alt="Study Explains How Some Minerals Can Change Color Repeatedly" border="0" data-original-height="618" data-original-width="1237" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjQLZ0ZzSP3uVdsOSnWOeeTDz1qI8A7UFmAoFRdqqefwC2P1wMBOMwEAFlpOzl2OS3jKGcHZtirvN7YI_lsoV1akhOB4J0FgVuXnVwu1WdKCXX0mC7tc8_Wz-xwNO4k7j-GCCY_LUGoKNqqt-HeAAoKJ34WdHtIno7JND__bc9HOFailkDP3tgurPgO/w640-h320/Scapolite%20-%20photo%20by%20Sami%20Vuori%20(1).jpg" title="White scapolite turns blue under UV irradiation. The coloration and reversion back to white after the removal of the UV source take only a few seconds, because atoms in the structure move short distances. Scapolite is a rather common mineral. This sample is from Afghanistan. Photo: Sami Vuori." width="640" /></a></td></tr><tr><td class="tr-caption" style="text-align: center;"><i>White
 scapolite turns blue under UV irradiation. The coloration and reversion
 back to white after the removal of the UV source take only a few 
seconds, because atoms in the structure move short distances. Scapolite 
is a rather common mineral. This sample is from Afghanistan. Photo: Sami
 Vuori.</i></td></tr></tbody></table><p>"There were no characterisation methods available for the research on color changing minerals, which is why we have developed new methods by ourselves. However, it is difficult to interpret the results unambiguously based on experimental data alone. In fact, we could not have reached the present conclusions without strong support from theoretical calculations, since only the combination of experimental and computational data shows the whole picture. We owe a great many thanks to our collaborator Professor Tangui Le Bahers and his group, who have developed and advanced suitable computational methods to such detail and accuracy that would not have been possible just a few years ago," reflects Lastusaari.<br /></p><p></p><h4 style="text-align: left;"><span style="font-family: georgia;">Hackmanite has amazing potential for applications</span></h4><p style="text-align: left;">The Intelligent Materials Research Group at the Department of Chemistry of the University of Turku, led by Lastusaari, has long conducted pioneering research on materials with light and color-related properties, especially on hackmanite. They are currently exploring numerous applications for hackmanite, such as possibly replacing LEDs and other light bulbs with the natural mineral and using it in X-ray imaging.<br /><br />One of the most interesting avenues that the researchers are currently exploring is a hackmanite-based dosimeter and passive detectors for the International Space Station, intended to be used to measure the radiation dose uptake of materials during space flights.<br /><br />"The strength of hackmanite's color depends on how much UV radiation it is exposed to, which means that the material can be used, for example, to determine the UV index of Sun's radiation. The hackmanite that will be tested on the space station will be used in a similar fashion, but this property can also be used in everyday applications. We have for example already developed a mobile phone application for measuring UV radiation that can be used by anyone," explains Sami Vuori. </p><p style="text-align: left;"><br /><u><i><span style="font-family: trebuchet;">The above story is based on <a href="https://www.utu.fi/en/news/press-release/natural-mineral-hackmanite-can-change-colour-almost-indefinitely-enabling" rel="noopener noreferrer nofollow" style="-webkit-text-stroke-width: 0px; background-color: white; border-radius: 0px; box-sizing: border-box; font-size: 14px; font-variant-caps: normal; font-variant-ligatures: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px;" target="_blank">Materials</a><span style="-webkit-text-stroke-width: 0px; background-color: white; display: inline; float: none; font-size: 14px; font-variant-caps: normal; font-variant-ligatures: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-decoration-color: initial; text-decoration-style: initial; text-decoration-thickness: initial; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px;"><span> </span>provided by<span> </span></span><a href="https://www.utu.fi/en" rel="noopener noreferrer nofollow" style="-webkit-text-stroke-width: 0px; background-color: white; border-radius: 0px; box-sizing: border-box; font-size: 14px; font-variant-caps: normal; font-variant-ligatures: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px;" target="_blank"><b style="border-radius: 0px; box-sizing: border-box; font-weight: bold;">University of Turku</b></a></span></i></u><span face=""Helvetica Neue", Helvetica, Arial, sans-serif" style="-webkit-text-stroke-width: 0px; background-color: white; color: #333333; display: inline; float: none; font-size: 14px; font-style: normal; font-variant-caps: normal; font-variant-ligatures: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-decoration-color: initial; text-decoration-style: initial; text-decoration-thickness: initial; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px;"><span style="color: black;"><u><i><span style="font-family: trebuchet;">.</span></i></u></span><span><span style="color: black;"><u><i><span style="font-family: trebuchet;"> </span></i></u></span><br /></span></span></p>

Study Explains How Some Minerals Can Change Color Repeatedly

Study Explains How Some Minerals Can Change Color Repeatedly. Tanzanite crystals Pleochroism. Photo: Spirifer_minerals While investigating h...

The Most Complete Baby Mammoth In North America Has Been FOUND

extinction, Fossils 8:39 PM

The Most Complete Baby Mammoth In North America Has Been FOUND

The Most Complete Baby Mammoth In North America Has Been FOUND. A well-preserved whole baby woolly mammoth was discovered at Treadstone Mine...

Utah Geologists Translate Vibrations of Rocky Landforms Into Audible Tones

Geology, Researches, USA 7:59 PM

<p></p><table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto;"><tbody><tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiK88p-kojmXZLO9hGKAJ6Edrs2E9ehZZgSNLYuawdJ-vpftvdJeJGUcWTIDiY9hz_oZQ3nwSLi5mUq8Vh8sWLxIs6nZ9G9mk-aDZgi4aN7KeXMvr7Ou61iv7bKOKUY_ZfFawxLUr0Kt0Ve46JSrpm5pgP3eSOJAlWKWmZlBHZ8p1NwdoRPDoYZtFpA/s1213/Utah%20geologists%20translate%20vibrations%20of%20rocky%20landforms%20into%20audible%20tones.jpg" style="margin-left: auto; margin-right: auto;"><img alt="Utah Geologists Translate Vibrations of Rocky Landforms Into Audible Tones" border="0" data-original-height="683" data-original-width="1213" height="360" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiK88p-kojmXZLO9hGKAJ6Edrs2E9ehZZgSNLYuawdJ-vpftvdJeJGUcWTIDiY9hz_oZQ3nwSLi5mUq8Vh8sWLxIs6nZ9G9mk-aDZgi4aN7KeXMvr7Ou61iv7bKOKUY_ZfFawxLUr0Kt0Ve46JSrpm5pgP3eSOJAlWKWmZlBHZ8p1NwdoRPDoYZtFpA/w640-h360/Utah%20geologists%20translate%20vibrations%20of%20rocky%20landforms%20into%20audible%20tones.jpg" title="Utah Geologists Translate Vibrations of Rocky Landforms Into Audible Tones" width="640" /></a></td></tr><tr><td class="tr-caption" style="text-align: center;">Utah Geologists Translate Vibrations of Rocky Landforms Into Audible Tones. PHOTO CREDIT: Geohazards research group</td></tr></tbody></table> <p style="text-align: left;"><span style="font-family: georgia;">These are the vibrations of Eagle Plume Tower, a rock landform in Southeastern Utah.<br />You won't see them move no matter how closely you watch.<br /><span style="color: white;">You won't hear their vibrations, even with your ear pressed to the cool sandstone. </span></span><br /><br />But new research shows that the red rock towers found in Southern Utah and throughout the Colorado Plateau are in constant motion, vibrating with their own signature rhythms as unique as their dramatic profiles against the depth of the blue desert sky.<br /><br />University of Utah researchers know well how rock towers and arches shimmy, twist and sway in response to far-off earthquakes, wind and even ocean waves. Their latest research compiles a first-of-its-kind dataset to show that the dynamic properties, i.e. the frequencies at which the rocks vibrate and the ways they deform during that vibration, can be largely predicted using the same mathematics that describe how beams in built structures resonate.<br /><br />Knowing these properties is crucial to understanding the seismic stability of a rock tower and its susceptibility to hazardous vibrations. But it’s tough to get the needed data, partly because getting to the base of the towers often requires traveling through treacherous terrain—and then someone has to climb them to place a seismometer at the top.<br /><br />With the help of experienced climbers, though, University of Utah researchers have now measured the dynamic properties of 14 rock towers and fins in Utah, creating a unique dataset with a variety of heights and tower shapes.<br /><br />“This ability to make predictions about a tower’s fundamental frequency using just the tower’s width, height, and material properties is powerful because that means someone doesn’t necessarily have to climb a 300-foot (100 m) tower with a seismometer to get this information,” says lead author Riley Finnegan, a doctoral student in geophysics. “And knowing this information is important for any assessments related to the seismic stability of a tower or potential vibration damage.”<br /></p><h4 style="text-align: left;"><span style="font-family: georgia;">Scaling the tops of towers</span></h4><p style="text-align: left;">Finnegan, Jeff Moore, associate professor of geology and geophysics, and colleagues have spent years measuring and cataloging arches and other rock forms to understand how they move. You can see their 3D models here and read about their studies of Rainbow Bridge, Castleton Tower, multiple arches including Delicate Arch and even the Matterhorn.<br /></p><div style="margin: 0px auto; width: 100%;">
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</div><br />Their new dataset includes the 279-foot (85 m) high monolith of Eagle Plume Tower and the 147-foot (45 m) high Petard Tower, both in Valley of the Gods, Bears Ears, Utah.<br /><br />Find photos, videos, animations of exaggerated tower movement, and even sped-up sound recordings of tower <a href="https://geohazards.earth.utah.edu/media.html" rel="nofollow" target="_blank">vibrations here.</a><br /><br />To get their seismometers to the tops of these towers, the researchers teamed up with climbing expert Kathryn Vollinger, who together with her partner ascended the towers hauling the instruments to the top. Then they waited while the instruments recorded data and carried them back down.<br /><br />The researchers drew on the help of others as well. Jackson Bodtker, a recent graduate now at the University of Calgary, climbed three towers in one day. Alex Dzubay, a senior majoring in geophysics, scrambled up a thousand-foot cliff to access one tower. Moore’s family even contributed, measuring dimensions of rock towers in Arizona.<br /><br />“So many talented, eager, and helpful people were involved in the fieldwork,” Finnegan says. “A group of us went to three of the sites after Kathryn’s climbs to fly the drone to make 3D models, and I personally could barely get to the baseof one of the towers, let alone start thinking about carrying our equipment to the base and then climb up with it all in tow.”<br /><p></p><h4 style="text-align: left;"><span style="font-family: georgia;">Respecting the land</span></h4><p style="text-align: left;">Some of the sites studied have special significance to local Native American tribes, including the towers in Valley of the Gods, Bears Ears, Utah. The valley, according to the Bears Ears Inter-Tribal Coalition, “…is considered sacred to the Navajo, who interpret the giant sandstone monuments as ancient Navajo warriors frozen in stone—and time.”<br /><br />Finnegan says the researchers met with teachers from Whitehorse High in Montezuma Creek near Valley of the Gods and that one of the students, Weston Manygoats, joined them for fieldwork. “He is extremely bright and hardworking, and we were very grateful for his assistance,” Finnegan says.<br /><br />The research team strove to practice respectful visitation during their fieldwork, and recommends that others visiting the Bears Ears area consult with guidelines from the Coalition and visit the Friends of Cedar Mesa Visitor Center in Bluff, UT. Visitors are asked to stay on marked trails, visit cultural sites with respect, leave any cultural objects as they are found, and avoid touching rock art.<br /></p><div style="margin: 0px auto; width: 100%;">
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</div><br />“We hope that by recognizing these towers are constantly in motion, trembling, swaying and shuddering in response to wind and energy coursing through the Earth, visitors to these sometimes sacred landscapes will have an added layer of respect, and ultimately that our measurements will inspire a spirit of care for these amazingly unique places,” Moore says.<br /><p></p><h4 style="text-align: left;"><span style="font-family: georgia;">Rocks swaying like trees</span></h4><p style="text-align: left;">In all, this study compiled ambient vibration data for 14 rock towers and fins collected over several years.  While the team had previously reported measurements from a single landform, the 120 m high Castleton Tower, the new compilation is larger and broader than any previously published dataset and spans a variety of tower heights and geometries.<br /><br />The results showed that the fundamental frequencies of the rock towers varied between ~1 Hz (one cycle per second) and 15 Hz, and that larger towers have lower fundamental frequencies. In general, the towers bend and sway like trees and tall buildings. At higher frequencies the towers twist around their central axis.<br /><br />“Probably most surprising to me was how well our data agreed with theory, and how well our models supported the data,” Finnegan says. That theory predicts that the fundamental frequency at which a beam vibrates is proportional to its width divided by its height squared. The rock towers largely followed that relationship.<br /><br />The predicted frequencies of the rock towers’ vibrations differed from the observed data by about 4%. And the predicted angle of the towers’ motions deviated from the actual data by 14° on average.”<br /><br />“Maybe I’m overly excited and surprised about this,” Finnegan says, “but I’ve made enough models of rock arches in some of our other work that frustratingly didn’t produce strong matches to the data, so it was refreshing to me to be able to predict tower modes given the geometry.”<br /><br />The new measurements, together with previously published data, provide guidance on estimating the natural frequencies of other rock towers, pillars and fins, in different settings across the world, values which are needed in order to conduct seismic stability and vibration risk assessments, as well as assess the probable intensity of past shaking. Knowing how to predict rock towers’ properties, Finnegan says, makes it much easier to assess the health of a tower with fewer measurements.<br /><br />“Some of the most rewarding times I have had in the field are times when I’m able to slow down, sit and listen and imagine these towers in motion,” Moore says. “We can’t see or hear or feel their motion, but it is very real and is always (and has always been) happening. For me, this new perspective creates a renewed and intimate connection with the landscape.”</p><h4 style="text-align: left;"><span style="font-family: georgia;">You can listen to of their <a href="https://geohazards.earth.utah.edu/media.html" rel="nofollow" target="_blank">rock music at</a>  <span style="color: #2b00fe;"><b><a href="https://geohazards.earth.utah.edu/images/towers/Eagle_50X.mp3" rel="nofollow" style="-webkit-text-stroke-width: 0px; background-color: white; font-size: 12.8px; font-style: normal; font-variant-caps: normal; font-variant-ligatures: normal; letter-spacing: normal; outline: none; text-align: left; text-decoration: none; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px;" target="_blank">Eagle Plume Tower</a> ,  <a href="https://geohazards.earth.utah.edu/images/towers/TidesofMind_50X.mp3" rel="nofollow" style="-webkit-text-stroke-width: 0px; background-color: white; font-size: 12.8px; font-style: normal; font-variant-caps: normal; font-variant-ligatures: normal; letter-spacing: normal; outline: none; text-align: left; text-decoration: none; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px;" target="_blank">Tides of Mind</a></b></span></span></h4><p><i><u> The above story is based on <a href="https://attheu.utah.edu/facultystaff/measuring-the-tempo-of-utahs-red-rock-towers/" rel="nofollow" target="_blank">materials </a>provided by th<a href="https://utah.edu/" rel="nofollow" target="_blank">e University of Utah.</a></u></i><br /></p>

Utah Geologists Translate Vibrations of Rocky Landforms Into Audible Tones

Utah Geologists Translate Vibrations of Rocky Landforms Into Audible Tones. PHOTO CREDIT: Geohazards research group These are the vibratio...

Tectonics of Convergent Plate Margins: New Insights Into Continental Geology

Earth News, Geology, Tectonic 9:40 PM

Tectonics of Convergent Plate Margins: New Insights Into Continental Geology

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Weird Water Dynamics Fuel Deep Earthquakes and Fist-Sized Diamonds

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Earth News, Geochemistry, Tectonic 9:29 PM

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Yellowstone's History of Hydrothermal Explosions Over the Past 14,000 Years

Earth History, Geology, Yellowstone 9:49 PM

<p><table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto;"><tbody><tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgHOO82AXBvn6gfDSOsjN9wzG4WWX0HMaQg9R-gqX4Ybh7UPy3na9v13Y_YqlNi2b3HKZBjDhpXmckq6Uk0flI4ETn0cAp0-udxqbJfj_oQxIEYkVPn1IJZpEqtntfY_9ZM2EYvyFMnQuAgFJmjuijcpN8BVrdXxu1jOh0XYXoXThC2N_xAOOBz1niS/s1210/yellowstone-volcano-area-hit-by-biggest-earthquake-for-5-years%20(1).jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="807" data-original-width="1210" height="426" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgHOO82AXBvn6gfDSOsjN9wzG4WWX0HMaQg9R-gqX4Ybh7UPy3na9v13Y_YqlNi2b3HKZBjDhpXmckq6Uk0flI4ETn0cAp0-udxqbJfj_oQxIEYkVPn1IJZpEqtntfY_9ZM2EYvyFMnQuAgFJmjuijcpN8BVrdXxu1jOh0XYXoXThC2N_xAOOBz1niS/w640-h426/yellowstone-volcano-area-hit-by-biggest-earthquake-for-5-years%20(1).jpg" title="Stock image showing a spring at Yellowstone National Park. GETTY IMAGES" width="640" /></a></td></tr><tr><td class="tr-caption" style="text-align: center;">Stock image showing a spring at Yellowstone National Park.<br />GETTY IMAGES</td></tr></tbody></table> <br /></p><p>While much of public attention on Yellowstone focuses on its potential to produce large supereruptions, the hazards that are much more likely to occur are smaller, violent hydrothermal explosions. Hydrothermal explosions occur when near-boiling water suddenly flashes into steam, releasing large amounts of energy. The energy release fractures the rock downward, often leaving behind a crater. The same sources that can produce these explosions are what give Yellowstone its well-known hot springs, geysers, and fumaroles.<br /><br />The Yellowstone Lake area in Yellowstone National Park hosts at least eight large craters produced by hydrothermal explosions, including three of the largest hydrothermal explosion craters known on Earth. Compared to other areas of interest within Yellowstone, hydrothermal explosion craters have not been as thoroughly studied. In a new study published on Tuesday in GSA Bulletin, researchers evaluated the history of hydrothermal explosions at Yellowstone Lake over the past 14,000.<br /><br />"The hydrothermal system in Yellowstone is the largest in the world and is driven by high heat flow over a large area, by high precipitation rates, and by active seismicity and deformation. Over 10,000 hydrothermal features are present in Yellowstone," said Lisa Morgan, lead author of the study. "For this study, we wanted to know more about the recent geologic history of Yellowstone Lake and what role hydrothermal activity has had in the lake, especially the role of hydrothermal explosions and their triggering mechanisms."<br /><br />The research team collected sediment cores from across the northern portion of Yellowstone Lake and correlated them with cores that were previously collected in the vicinity, with the goal of characterizing their chemical and physical attributes and identifying hydrothermal explosion deposits in the cores.<br /><br />"Hydrothermal explosion sediments deposited underwater had never been described in published literature. In analyzing the cores, we made a lot of discoveries and had several surprises. Number one was how different the explosion deposits found in the cores looked from explosion deposits on land. That was to be expected since one was deposited through a water column and one was deposited on land," said Morgan.<br /><br />The researchers found evidence for at least 16 deposits in the cores that were produced by hydrothermal explosions. While 14 of the deposits represented more localized explosion events, two of the deposits were associated with two of Yellowstone's largest hydrothermal explosion craters: the Mary Bay and Elliott's craters.<br /><br />The Mary Bay hydrothermal explosion occurred 13,000 years ago and resulted in a 2.5-km (1.5-mi) wide crater, which is partly submerged under the lake. While deposits from the Mary Bay explosion exposed on land had been previously studied, the sediment cores from the lake demonstrated that the extent of its deposits was larger than previously thought and that the lake level must have been lower at the time of the explosion.<br /><br />The researchers concluded that the Mary Bay explosion was triggered by a sudden 14-m (46-ft) drop in lake level caused by a seismic event and a tsunami that eroded the outlet waterway of Yellowstone Lake.<br /><br />The Elliott's Crater explosion occurred 8,000 years ago and produced a 700-m (2,300-ft) wide crater. The crater is fully submerged underwater, and no deposits from the explosion are exposed on land. Based on records in the cores, the deposits from Elliott's Crater were also more broadly distributed than previously thought.<br /><br />Differing from how the Mary Bay Crater likely formed, the researchers determined that Elliott's Crater formed when a seismic event fractured the dome cap of the hydrothermal system. In Yellowstone Lake, hydrothermal domes form when underlying pockets of gas or gas-charged fluids cause overlying sediments to arch upwards. Rupturing this dome would result in a sudden loss of pressure, triggering a hydrothermal explosion.<br /><br />Many of the smaller deposits in the sediment cores were from previously unknown younger hydrothermal explosions. As has been consistent with previous studies of the explosion craters, there appears to be no relation between them and volcanic eruptions at Yellowstone.<br /><br />"Given what we see from Yellowstone Lake and elsewhere in Yellowstone, hydrothermal explosions of various scales will continue to occur," said Morgan.<br /></p><p><br /><i><u><span style="font-family: trebuchet;">The above story is based on <a href="https://www.geosociety.org/GSA/News/pr/2022/22-33.aspx" rel="noopener noreferrer nofollow" style="-webkit-text-stroke-width: 0px; background-color: white; border-radius: 0px !important; box-sizing: border-box; color: #004276; font-size: 14px; font-variant-caps: normal; font-variant-ligatures: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px;" target="_blank">Materials</a><span style="-webkit-text-stroke-width: 0px; background-color: white; color: #333333; display: inline !important; float: none; font-size: 14px; font-variant-caps: normal; font-variant-ligatures: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-decoration-color: initial; text-decoration-style: initial; text-decoration-thickness: initial; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px;"><span> </span>provided by<span> </span></span><a href="https://www.geosociety.org/" rel="noopener noreferrer nofollow" style="-webkit-text-stroke-width: 0px; background-color: white; border-radius: 0px !important; box-sizing: border-box; color: #004276; font-size: 14px; font-variant-caps: normal; font-variant-ligatures: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px;" target="_blank"><strong style="border-radius: 0px !important; box-sizing: border-box; font-weight: bold;">Geological Society of America</strong></a><span style="-webkit-text-stroke-width: 0px; background-color: white; color: #333333; display: inline !important; float: none; font-size: 14px; font-variant-caps: normal; font-variant-ligatures: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-decoration-color: initial; text-decoration-style: initial; text-decoration-thickness: initial; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px;">.</span></span></u></i></p>

Yellowstone's History of Hydrothermal Explosions Over the Past 14,000 Years

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Scientists Discover “Ghost” Fossils – “Completely Unexpected”

Earth History, Fossils 9:33 PM

<p></p><table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto;"><tbody><tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhKotSwn7iXiSc2ZxhuetHwDNHJUVbCKHb3kNiHMx-8IgEG7MiMg11JVKMSXoQZdOg0ZfaJZ05-Kv2lVQr3nu0CHzEcYwxC7AemV6kvGTaNTrmqPXSxePvA3sqfEQewyA5jL6yYaUFK5XnVvvnbnf1ino11OIhTbobfWWBZdmNBGVNcI2flwcBdbscW/s1209/Microscopic-Plankton-Cell-Wall-Coverings-Preserved-As-Ghost-Fossil-Impressions%20(1).jpg" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1034" data-original-width="1209" height="549" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhKotSwn7iXiSc2ZxhuetHwDNHJUVbCKHb3kNiHMx-8IgEG7MiMg11JVKMSXoQZdOg0ZfaJZ05-Kv2lVQr3nu0CHzEcYwxC7AemV6kvGTaNTrmqPXSxePvA3sqfEQewyA5jL6yYaUFK5XnVvvnbnf1ino11OIhTbobfWWBZdmNBGVNcI2flwcBdbscW/w640-h549/Microscopic-Plankton-Cell-Wall-Coverings-Preserved-As-Ghost-Fossil-Impressions%20(1).jpg" title="The images show the impressions of a collapsed cell-wall covering (a coccosphere) on the surface of a fragment of ancient organic matter (left) with the individual plates (coccoliths) enlarged to show the exquisite preservation of sub-micron-scale structures (right). Credit: S.M. Slater, P. Bown / Science journal" width="640" /></a></td></tr><tr><td class="tr-caption" style="text-align: center;"><span style="font-family: times;">The images show the impressions of a collapsed cell-wall covering (a coccosphere) on the surface of a fragment of ancient organic matter (left) with the individual plates (coccoliths) enlarged to show the exquisite preservation of sub-micron-scale structures (right). Credit: S.M. Slater, P. Bown / Science journal</span><br /></td></tr></tbody></table> <p></p><p><span style="font-family: georgia;">A previously unrecognized mode of fossilization of ancient microbes may explain how some of Earth’s oldest microfossils formed, according to new research.</span><br /></p><p>An international team of scientists from UCL (University College London), the Swedish Museum of Natural History, Natural History Museum (London) and the University of Florence have found a remarkable type of fossilisation that has remained almost entirely overlooked until now.<br /><br />The fossils are microscopic imprints, or "ghosts," of single-celled plankton, called coccolithophores, that lived in the seas millions of years ago, and their discovery is changing our understanding of how plankton in the oceans are affected by climate change.<br /><br />Coccolithophores are important in today's oceans, providing much of the oxygen we breathe, supporting marine food webs, and locking carbon away in seafloor sediments. They are a type of microscopic plankton that surround their cells with hard calcareous plates, called coccoliths, and these are what normally fossilize in rocks.<br /><br />Declines in the abundance of these fossils have been documented from multiple past global warming events, suggesting that these plankton were severely affected by climate change and ocean acidification. However, a study published today in the journal Science presents new global records of abundant ghost fossils from three Jurassic and Cretaceous warming events (94, 120 and 183 million years ago), suggesting that coccolithophores were more resilient to past climate change than was previously thought.<br /><br />"The discovery of these beautiful ghost fossils was completely unexpected," says Dr. Sam Slater from the Swedish Museum of Natural History. "We initially found them preserved on the surfaces of fossilized pollen, and it quickly became apparent that they were abundant during intervals where normal coccolithophore fossils were rare or absent -- this was a total surprise!"<br /></p><div style="margin: 0px auto; width: 100%;">
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</div><br />Despite their microscopic size, coccolithophores can be hugely abundant in the present ocean, being visible from space as cloud-like blooms. After death, their calcareous exoskeletons sink to the seafloor, accumulating in vast numbers, forming rocks such as chalk.<br /><br />"The preservation of these ghost nannofossils is truly remarkable," says Professor Paul Bown (UCL). "The ghost fossils are extremely small -- their length is approximately five thousandths of a millimetre, 15 times narrower than the width of a human hair -- but the detail of the original plates is still perfectly visible, pressed into the surfaces of ancient organic matter, even though the plates themselves have dissolved away."<br /><br />The ghost fossils formed while the sediments at the seafloor were being buried and turned into rock. As more mud was gradually deposited on top, the resulting pressure squashed the coccolith plates and other organic remains together, and the hard coccoliths were pressed into the surfaces of pollen, spores and other soft organic matter. Later, acidic waters within spaces in the rock dissolved away the coccoliths, leaving behind just their impressions -- the ghosts.<br /><br />"Normally, palaeontologists only search for the fossil coccoliths themselves, and if they don't find any then they often assume that these ancient plankton communities collapsed," explains Professor Vivi Vajda (Swedish Museum of Natural History). "These ghost fossils show us that sometimes the fossil record plays tricks on us and there are other ways that these calcareous nannoplankton may be preserved, which need to be taken into account when trying to understand responses to past climate change."<br /><br />Professor Silvia Danise (University of Florence) says: "Ghost nannofossils are likely common in the fossil record, but they have been overlooked due to their tiny size and cryptic mode of preservation. We think that this peculiar type of fossilization will be useful in the future, particularly when studying geological intervals where the original coccoliths are missing from the fossil record."<br /><br />The study focused on the Toarcian Oceanic Anoxic Event (T-OAE), an interval of rapid global warming in the Early Jurassic (183 million years ago), caused by an increase in CO2-levels in the atmosphere from massive volcanism in the Southern Hemisphere. The researchers found ghost nannofossils associated with the T-OAE from the UK, Germany, Japan and New Zealand, but also from two similar global warming events in the Cretaceous: Oceanic Anoxic Event 1a (120 million years ago) from Sweden, and Oceanic Anoxic Event 2 (94 million years ago) from Italy.<br /><br />"The ghost fossils show that nannoplankton were abundant, diverse and thriving during past warming events in the Jurassic and Cretaceous, where previous records have assumed that plankton collapsed due to ocean acidification," explains Professor Richard Twitchett (Natural History Museum, London). "These fossils are rewriting our understanding of how the calcareous nannoplankton respond to warming events."<br /><br />Finally, Dr. Sam Slater explains: "Our study shows that algal plankton were abundant during these past warming events and contributed to the expansion of marine dead zones, where seafloor oxygen-levels were too low for most species to survive. These conditions, with plankton blooms and dead zones, may become more widespread across our globally warming oceans."<p></p><p> </p><p><u><i><span style="font-family: trebuchet;">The above story is based on <span style="color: black;"><a href="https://www.ucl.ac.uk/news/2022/may/discovery-ghost-fossils-reveals-plankton-resilience-past-global-warming-events" rel="noopener noreferrer nofollow" style="-webkit-text-stroke-width: 0px; background-color: white; border-radius: 0px; box-sizing: border-box; font-size: 14px; font-variant-caps: normal; font-variant-ligatures: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px;" target="_blank">Materials</a><span style="-webkit-text-stroke-width: 0px; background-color: white; display: inline; float: none; font-size: 14px; font-variant-caps: normal; font-variant-ligatures: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-decoration-color: initial; text-decoration-style: initial; text-decoration-thickness: initial; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px;"><span> </span>provided by<span> </span></span><a href="https://www.ucl.ac.uk/" rel="noopener noreferrer nofollow" style="-webkit-text-stroke-width: 0px; background-color: white; border-radius: 0px; box-sizing: border-box; font-size: 14px; font-variant-caps: normal; font-variant-ligatures: normal; font-weight: 400; letter-spacing: normal; outline: currentcolor none 0px; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px;" target="_blank"><b style="border-radius: 0px; box-sizing: border-box; font-weight: bold;">University College London</b></a><span style="-webkit-text-stroke-width: 0px; background-color: white; display: inline; float: none; font-size: 14px; font-variant-caps: normal; font-variant-ligatures: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-decoration-color: initial; text-decoration-style: initial; text-decoration-thickness: initial; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px;">.<span> </span></span></span></span></i></u> </p>

Scientists Discover “Ghost” Fossils – “Completely Unexpected”

The images show the impressions of a collapsed cell-wall covering (a coccosphere) on the surface of a fragment of ancient organic matter (le...

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Earth News, Earth's magnetic field, Tectonic 8:34 PM

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