Geology In

World's Oldest Bug is Fossil Millipede From Scotland

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<tr><td class="tr-caption" style="text-align: center;">UT Austin scientists found that the fossil millipede Kampecaris obanensis was 425 million years old. Credit: British Geological Survey</td></tr>
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<span style="font-family: "georgia" , "times new roman" , serif;">Some millipedes can live for years, but one particular millipede inadvertently made paleontology history 425 million years after its demise. </span><br />
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A 425-million-year-old millipede fossil from the Scottish island of Kerrera is the world's oldest "bug" -- older than any known fossil of an insect, arachnid or other related creepy-crawly, according to researchers at The University of Texas at Austin.<br />
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The findings offer new evidence about the origin and evolution of bugs and plants, suggesting that they evolved much more rapidly than some scientists believe, going from lake-hugging communities to complex forest ecosystems in just 40 million years.<br />
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"It's a big jump from these tiny guys to very complex forest communities, and in the scheme of things, it didn't take that long," said Michael Brookfield, a research associate at UT Austin's Jackson School of Geosciences and adjunct professor at the University of Massachusetts Boston. "It seems to be a rapid radiation of evolution from these mountain valleys, down to the lowlands, and then worldwide after that."<br />
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The research was recently published in the journal Historical Biology. Brookfield led the study with co-authors including Elizabeth Catlos, an associate professor in the Jackson School's Department of Geological Sciences, and Stephanie Suarez, a doctoral student at the University of Houston who made improvements to the fossil dating technique used in the study when she was an undergraduate at the Jackson School.<br />
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The team found that the ancient millipede fossil is 425 million years old, or about 75 million years younger than the age other scientists have estimated the oldest millipede to be using a technique known as molecular clock dating, which is based on DNA's mutation rate. Other research using fossil dating found that the oldest fossil of a land-dwelling, stemmed plant (also from Scotland) is 425 million years old and 75 million years younger than molecular clock estimates.<br />
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Although it's certainly possible there are older fossils of both bugs and plants, Brookfield said that the fact they haven't been found -- even in deposits known for preserving delicate fossils from this era -- could indicate that the ancient millipede and plant fossils that have already been discovered are the oldest specimens.<br />
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If that's the case, it also means both bugs and plants evolved much more rapidly than the timeline indicated by the molecular clock. Bountiful bug deposits have been dated to just 20 million years later than the fossils. And by 40 million years later, there's evidence of thriving forest communities filled with spiders, insects and tall trees.<br />
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"Who is right, us or them?" Catlos said. "We're setting up testable hypotheses -- and this is where we are at in the research right now."<br />
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Given their potential evolutionary significance, Brookfield said that he was surprised that this study was the first to address the age of the ancient millipedes.<br />
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Suarez said a reason could be the difficulty of extracting zircons -- a microscopic mineral needed to precisely date the fossils -- from the ashy rock sediment in which the fossil was preserved. As an undergraduate researcher at the Jackson School, Suarez developed a technique for separating the zircon grain from this type of sediment. It's a process that takes practice to master. The zircons are easily flushed away when trying to loosen their grip on the sediment. And once they are successfully released from the surrounding rock, retrieving the zircons involves an eagle-eyed hunt with a pin glued to the tip of a pencil.<br />
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"That kind of work trained me for the work that I do here in Houston," Suarez said. "It's delicate work."<br />
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As an undergraduate, Suarez used the technique to find that a different millipede specimen, thought to be the oldest bug specimen at the time, was about 14 million years younger than estimated -- a discovery that stripped it of the title of oldest bug. Using the same technique, this study passes the distinction along to a new specimen.<br />
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The research was funded by the Jackson School, the Max Kade Foundation and DFG Scientific Instrumentation and Information Technology.<br />
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<u><i><span style="font-family: "trebuchet ms" , sans-serif;">The above story is based on <a href="http://www.jsg.utexas.edu/news/2020/05/worlds-oldest-bug-is-fossil-millipede-from-scotland/" rel="nofollow" target="_blank">Materials</a> provided by <a href="http://www.utexas.edu/" rel="nofollow" target="_blank">University of Texas at Austin</a>.</span></i></u></div>

World's Oldest Bug is Fossil Millipede From Scotland

UT Austin scientists found that the fossil millipede Kampecaris obanensis was 425 million years old. Credit: British Geological Survey ...

Hawaiian Volcano Puhahonu is Earth’s Biggest and Hottest Shield Volcano

Geology, Researches, volcano 7:08 PM

Hawaiian Volcano Puhahonu is Earth’s Biggest and Hottest Shield Volcano

Gardner Pinnacles. Image credit: Andy Collins, NOAA. With two barren peaks that rise only about 170 feet above sea level, the now ext...

New Clues to Deep Earthquake Mystery

Earthquakes, Tectonic 6:18 PM

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<tr><td class="tr-caption" style="text-align: center;">Subduction zones occur where one tectonic plate dives under another.</td></tr>
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A new understanding of our planet's deepest earthquakes could help unravel one of the most mysterious geophysical processes on Earth.<br /><br />Deep earthquakes -- those at least 300 kilometers below the surface -- don't typically cause damage, but they are often widely felt. These earthquakes can provide vital clues to understanding plate tectonics and the structure of the Earth's interior. Due to the extremely high temperature and pressures where deep earthquakes occur, they likely stem from different physical and chemical processes than earthquakes near the surface. But it's hard to gather information about deep earthquakes, so scientists don't have a solid explanation for what causes them.<br /><br />"We can't directly see what's happening where deep earthquakes occur," said Magali Billen, professor of geophysics in the UC Davis Department of Earth and Planetary Sciences.</div>
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<span style="font-family: Georgia, "Times New Roman", serif;">What's driving deep earthquakes?</span></h4>
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Billen builds numerical simulations of subduction zones, where one plate sinks below another, to better understand the forces controlling plate tectonics. Her recent work helps explain the distribution of deep earthquakes, showing that they most often strike in regions of "high strain" where a sinking tectonic plate bends and folds.<br /><br />"These models provide compelling evidence that strain rate is an important factor in controlling where deep earthquakes occur," she said.<br /><br />The new understanding that deformation is a major factor in deep earthquakes should help scientists resolve which mechanisms trigger deep earthquakes and can provide new constraints on subduction zone structure and dynamics, Billen said.<br /><br />"Once we understand deep earthquake physics better, we will be able to extract even more information about the dynamics of subduction, the key driver of plate tectonics," she said.<br /><br />Her findings were published May 27 in the journal Science Advances.</div>
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<span style="font-family: Georgia, "Times New Roman", serif;">New way to study deep earthquakes</span></h4>
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Deep earthquakes occur in subduction zones -- where one of the tectonic plates floating on the surface of the Earth dives under another and is "subducted" into the mantle. Within the sinking slabs of crust, earthquakes cluster at some depths and are sparse in others. For example, many slabs exhibit large gaps in seismic activity below 410 kilometers in depth.<br /><br />The gaps in seismicity line up with regions of the slab that are deforming more slowly in the numerical models, Billen said.<br /><br />"Deformation is not the same everywhere in the plate," Billen said. "That's really what's new here."<br /><br />Billen's research was not originally intended to investigate deep earthquakes. Rather, she was trying to understand the slow back-and forth motion of deep ocean trenches, where plates bend downward in subduction zones.<br /><br />"I decided out of curiosity to plot the deformation in the plate, and when I looked at the plot, the first thing that popped in my mind was 'wow, this looks like the distribution of deep earthquakes,'" she said. "It was a total surprise."</div>
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<span style="font-family: Georgia, "Times New Roman", serif;">Mimicking the deep Earth</span></h4>
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Billen's model incorporates the latest data about phenomena such as the density of minerals, different layers in the sinking plate, and experimental observations of how rocks behave at high temperatures and pressures.<br /><br />"This is the first model that really brings together the physical equations that describe the sinking of the plates and key physical properties of the rocks," Billen said.<br /><br />The results cannot distinguish between possible causes for deep earthquakes. However, they do provide new ways to explore what causes them, Billen said.<br /><br />"Taking into account the added constraint of strain-rate should help to resolve which mechanisms are active in the subducting lithosphere, with the possibility that multiple mechanisms may be required," she said.</div>
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<br /><u><i><span style="font-family: "Trebuchet MS", sans-serif;">The above story is based on  <a href="https://www.ucdavis.edu/news/new-clues-deep-earthquake-mystery" rel="nofollow" target="_blank">Materials</a> provided by <a href="http://www.ucdavis.edu/" rel="nofollow" target="_blank">University of California - Davis</a>.</span></i></u></div>
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New Clues to Deep Earthquake Mystery

Subduction zones occur where one tectonic plate dives under another. A new understanding of our planet's deepest earthquakes cou...

Rare, Mysterious Diamond Found in West Virginia

Diamonds, Geochemistry 6:42 PM

Rare, Mysterious Diamond Found in West Virginia

Jones diamond, photographed at Rich Creek Bank in Peterstown, 1968 Diamonds don't exist naturally in West Virginia, yet one of t...

Thunderegg: Ordinary Rocks With Crystal Surprise Inside!

gemstones, Mineralogy 7:35 PM

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<tr><td class="tr-caption" style="text-align: center;">Thunderegg. Credit: Bill The Eggman</td></tr>
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</span> A <b>thunderegg </b>(or thunder egg) is a nodule-like rock, similar to a filled geode, that is formed within rhyolitic volcanic ash layers. </div>
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Thundereggs are rough spheres, most about the size of a baseball—though they can range from a little more than a centimeter to over a meter across. They usually contain centres of chalcedony which may have been fractured followed by deposition of agate, jasper or opal, either uniquely or in combination.</div>
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Thundereggs usually look like ordinary rocks on the outside, but slicing them in half and polishing them may reveal intricate patterns and colours. A characteristic feature of thundereggs is that (like other agates) the individual beds they come from can vary in appearance, though they can maintain a certain specific identity within them.</div>
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<span style="font-family: Georgia, "Times New Roman", serif;">Thunderegg Vs. Geode</span></h4>
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Thunderegg is not synonymous with either geode or agate. A <b>geode </b>is a simple term for a rock with a hollow in it, often with crystal formation/growth. A thunderegg on the other hand is a specific geological structure. A thunderegg may be referred to as a <b>geode </b>if it has a hollow in it, but not all geodes are thundereggs because there are many different ways for a hollow to form. Similarly, a thunderegg is just one of the forms that agate can assume.</div>
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<span style="font-family: Georgia, "Times New Roman", serif;">Formation</span></h4>
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Thundereggs are found in flows of rhyolite lava. They form in gas pockets in the lava, which act as molds, from the action of water percolating through the porous rock carrying silica in solution. The cooled bubbles were gradually filled by water percolating through the porous rock carrying rich quantities of silica (quartz). </div>
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The deposits lined and filled the cavity, first with a darker matrix material, then an inner core of agate or chalcedony. The various colors come from differences in the minerals found in the soil and rock that the water has moved through.<br />
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The agate, chalcedony, and quartz veins and open-space-fillings within voids in the spherulites formed later by multiple cycles of hydrothermal fluids. Hydrothermal fluids are a mixture of late-stage fluids escaping the magma and local ground water. <br />
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The fluids contain some elements from the original magma and also dissolved minerals from the country rock. The amount of ions that the fluid can dissolve depends upon pH, temperature, pressure, and composition of the fluid. The hydrothermal fluids move through fractures in the rocks, which crosscut the igneous textures, and form veins or banded agate, chalcedony, and quartz. <br />
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Some of these fluids seep through microscopic pores and into spherulites and gas pockets in the volcanic rocks, and they precipitate crystals along the walls of the cavity, forming geodes and geode-like spherulites. Other fluids seep through fractures and gas and other void spaces in the spherulites. Because of their formation by multiple hydrothermal events, each thunderegg provides clues as to its unique formation.<br />
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<tr><td class="tr-caption" style="text-align: center;">Credit: John Meinen</td></tr>
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<span style="font-family: Georgia, "Times New Roman", serif;">How to Spot Thundereggs?</span></h4>
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Though thundereggs appear as rocks, they can be easily identifiable by the abnormally round and bumpy brown-gray exteriors. Usually, thundereggs lie relatively close to the Earth's surface, embedded in the clay of the tuff, where they were formed. During the time, the tuff has been decayed to soft mud and clay, making rock-like thundereggs noticeable.<span style="font-family: Georgia, "Times New Roman", serif;"><br /></span><h4>
<span style="font-family: Georgia, "Times New Roman", serif;">Where to Find Thundereggs?</span></h4>
Thundereggs are found globally where conditions are optimal. In the US, Oregon is one of the most famous thunderegg locations. The regions of Central and Eastern Oregon are the most popular in the world for thundereggs hunting. The best productive areas are located in the high desert of Central Oregon near Prineville, Madras and in the Ochoco National Forest (Central Oregon). Also, thundereggs can be collected in Succor Creek Creek Canyon (Eastern Oregon)<ul style="text-align: left;">
<li><b>White Fir Springs</b></li>
<li><b>White Rock Springs</b></li>
<li><b>Whistler Springs</b></li>
<li><b>Richardson Rock Ranch</b></li>
<li><b>Succor Creek Canyon</b></li>
<li><b>Alvord Desert</b></li>
<li><b>Owyhee Reservoir  </b></li>
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<span style="color: blue;"><b><span style="font-family: "georgia" , "times new roman" , serif;">See also:</span></b></span></div>
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<span style="font-family: "georgia" , "times new roman" , serif;"><a href="https://www.geologyin.com/2018/07/where-to-find-sunstone-in-oregon.html" target="_blank">Where to Find Sunstone in Oregon?</a></span></div>
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<span style="font-family: "georgia" , "times new roman" , serif;"><a href="https://www.geologyin.com/2017/07/dig-your-own-unique-opals-from-nevada.html" target="_blank">Dig Your Own Unique Opals From Nevada </a></span></div>
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<a href="https://www.geologyin.com/2017/06/where-to-find-opals-in-oregon.html" target="_blank"><span style="font-family: "georgia" , "times new roman" , serif;">Opals in Oregon</span></a></div>
</div>

Thunderegg: Ordinary Rocks With Crystal Surprise Inside!

Thunderegg. Credit: Bill The Eggman A thunderegg (or thunder egg) is a nodule-like rock, similar to a filled geode, that is formed...

Giant Tectonic Plate Under Indian Ocean is Breaking in Two

earth, Geology 11:36 PM

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<tr><td class="tr-caption" style="text-align: center;">This map shows the seafloor topography and deformation below it at a fracture in the Wharton Basin. This fracture likely formed when the ocean crust was formed, but now this fracture is being turned into a new plate boundary. The purple-colored depressions are indicative of a strike-slip fault, which is the same kind of fault as the San Andreas Fault in California.  (Image credit: Aurélie Coudurier-Curveur; Coudurier‐Curveur, A. et al. Geophysical Research Letters (2020); CC BY 4.0)</td></tr>
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The giant tectonic plate under the Indian Ocean is going through a rocky breakup … with itself.<br />
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Bathymetric and seismic data point to a new plate boundary in a fracture-riddled zone beneath the northern Indian Ocean.<br />
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Tectonic plates blanket the Earth like a patchwork quilt. Now, researchers think they’ve found a new plate boundary—a line of stitching in that tectonic quilt—in the northern Indian Ocean. This discovery, made using bathymetric and seismic data, supports the hypothesis that the India-Australia-Capricorn plate is breaking apart, the team suggests.<br />
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<span style="font-family: "georgia" , "times new roman" , serif;">Earthquakes in Unexpected Places</span></h4>
In 2012, two enormous earthquakes occurred near Indonesia. But these massive temblors—magnitudes 8.6 and 8.2—weren’t associated with the region’s notorious Andaman-Sumatra subduction zone. Instead, they struck within the India-Australia-Capricorn plate, which made them unusual because most earthquakes occur at plate boundaries.<br />
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These earthquakes “reactivated the debate” about the India-Australia-Capricorn plate, said Aurélie Coudurier-Curveur, a geoscientist at the Institute of Earth Physics of Paris.<br />
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Some scientists have proposed that this plate, which underlies most of the Indian Ocean, is breaking apart. That’s not a wholly unexpected phenomenon because this plate is being tugged in multiple directions, said Coudurier-Curveur. Its eastern extent is sliding under the Sunda plate, but its northern portion is buckling up against the Himalayas, which are acting like a backstop.<br />
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“There’s a velocity difference that is potentially increasing,” said Coudurier-Curveur, who completed this work while at the Earth Observatory of Singapore at Nanyang Technological University.<br />
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<span style="font-family: "georgia" , "times new roman" , serif;">Zooming in on Fractures</span></h4>
Coudurier-Curveur and her colleagues studied one particularly fracture riddled region of the India-Australia-Capricorn plate near the Andaman-Sumatra subduction zone. They used seismic reflection imaging and multibeam bathymetry, which involve bouncing sound waves off sediments and measuring the returning signals, to look for structures at and below seafloor consistent with an active fault.<br />
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Along one giant crack that the team dubbed F6a, Coudurier-Curveur and her colleagues found 60 pull-apart basins, characteristic depressions that can form along strike-slip plate boundaries. The team showed that the basins followed a long, linear track that passed near the epicenters of both of the 2012 earthquakes.<br />
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“It’s at least 1,000 kilometers,” said Coudurier-Curveur. “It might be even longer, but we don’t have the data to show where it extends.” This feature, the team surmised, was consistent with being a plate boundary. An important next step was to estimate its slip rate.<br />
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<span style="font-family: "georgia" , "times new roman" , serif;">Slower Than San Andreas</span></h4>
To do that, the scientists relied on two quantities: the length of the largest, and presumably oldest, pull-apart basin (roughly 5,800 meters) and the duration of the most recent episode of fault activity (roughly 2.3 million years). By dividing the length of the pull-apart basin by this time interval, they calculated a maximum slip rate of about 2.5 millimeters per year. That’s roughly tenfold slower than the rate along other strike-slip plate boundaries like the San Andreas Fault but not much slower than the slip rates of the Dead Sea Fault and the Owen Fracture Zone, the team noted.<br />
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On the basis of that slip rate, Coudurier-Curveur and her collaborators estimated the return interval for an earthquake like the magnitude 8.6 one reported in April 2012. Assuming that such an event releases several tens of meters of coseismic slip, a similar earthquake might occur every 20,000 years or so, said Coudurier-Curveur. “Once you release the stress, you need a number of years to build that stress again.”<br />
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<u><i><span style="font-family: "trebuchet ms" , sans-serif;">The above story is based on <a href="https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2020GL087362" rel="nofollow" target="_blank">materials </a>provided by <a href="https://agupubs.onlinelibrary.wiley.com/" rel="nofollow" target="_blank">American Geophysical Union</a>.</span></i></u></div>