tag:blogger.com,1999:blog-55899006261438319592024-03-18T02:11:52.168-07:00Earth Science GuyPut your email address in the box below and "submit" to be notified when a new post is added. Rod Bensonhttp://www.blogger.com/profile/07896836810905406697noreply@blogger.comBlogger192125tag:blogger.com,1999:blog-5589900626143831959.post-19538683636540812362023-10-18T19:09:00.014-07:002023-12-09T16:42:37.525-08:00Montana Outdoors (magazine) articles with questions<div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgusAcNLsDB6ZDnQp1h6qqk_F7cmlc5BK1PgPOkYNp7v2u9ZDzBybZcl2gK_GNCWzGN1AipZ5WCkZ0nlJN76onRWFOhFng4KhPXHcenjz3KHAIdsDOhuKK5j6jMFBM3bzpD6JDMtnjNx5-IC8FdT-TA-shozLXtKTvTZJb0-RmpGi5EdSSMfTicUA05aUs/s579/P1160467.jpg" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" width="600" data-original-height="331" data-original-width="579" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgusAcNLsDB6ZDnQp1h6qqk_F7cmlc5BK1PgPOkYNp7v2u9ZDzBybZcl2gK_GNCWzGN1AipZ5WCkZ0nlJN76onRWFOhFng4KhPXHcenjz3KHAIdsDOhuKK5j6jMFBM3bzpD6JDMtnjNx5-IC8FdT-TA-shozLXtKTvTZJb0-RmpGi5EdSSMfTicUA05aUs/s600/P1160467.jpg"/></a></div>
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I've been working with Montana Fish, Wildlife & Parks to write evaluations (worksheets) that go along with articles from their <B>Montana Outdoors Magazine</B>. Below is a list of articles and assignments that I have completed. Each worksheet includes teacher notes, possible bell-ringers, and an answer key. The assignments are best-suited for high school biology students or students taking environmental science. <br>-Rod Benson<P>
<b>1. PDF Article about delisting grizzly bears:</b> <a href="https://fwp.mt.gov/binaries/content/assets/fwp/montana-outdoors/2023/grizzly2023.pdf"><b>Ready for the Handoff</b></a> <P>
Worksheet with questions - <a href="https://fwp.mt.gov/binaries/content/assets/fwp/education/literacy-program/readyhandoffdone.pdf">Ready for the Handoff worksheet</a> <P>
Ready for the Handoff <a href="https://create.kahoot.it/share/ready-for-the-handoff-grizzlies-in-montana/bc20a991-25e2-441d-9f19-c4ad2e9625a5">Kahoot Game</a> <P>
<b>2. PDF Article about amphibians:</b> <a href="https://fwp.mt.gov/binaries/content/assets/fwp/education/literacy-program/its-not-easy-being-green-article.pdf"><b>It’s Not Easy Being Green</b></a> <P>
<a href="https://fwp.mt.gov/binaries/content/assets/fwp/education/literacy-program/its-not-easy-being-green-evaluation.pdf">It's Not Easy Being Green Worksheet</a> <P>
<b>3. PDF Article about raptor identification:</b> <a href="https://fwp.mt.gov/binaries/content/assets/fwp/education/literacy-program/16-raptors-every-montanan-should-know-article.pdf"><b>16 Raptors That Every Montanan Should (Kinda) Know</b></a> <P>
<a href="https://fwp.mt.gov/binaries/content/assets/fwp/education/literacy-program/16-raptors-every-montanan-should-know-evaluation.pdf">Raptors Worksheet</a> <P>
<b>4. PDF Article about</b> <a href="https://fwp.mt.gov/binaries/content/assets/fwp/education/literacy-program/on-the-prowl-article---ais.pdf"><b>Aquatic Invasive Species<b></b></b></a> <P>
<a href="https://fwp.mt.gov/binaries/content/assets/fwp/education/literacy-program/on-the-prowl---ais--evaluation.pdf">Aquatic Invasive Species Worksheet</a><P>
<b>5. PDF Article about managing wildlife -</b> <a href="https://fwp.mt.gov/binaries/content/assets/fwp/education/literacy-program/micro-and-macro-article.pdf"><b>Micro and Macro</b></a> <P>
The worksheet for this article can be found on this <a href="https://fwp.mt.gov/education/montana-outdoors-literacy-program">web page</a>.<P>
<b>6. PDF Articleabout the mental health benefits of spending time outdoors:</b> <a href="https://fwp.mt.gov/binaries/content/assets/fwp/education/literacy-program/a-healthy-dose-of-nature-article.pdf"><b>A Healthy Dose of Nature</b></a> <P>
<a href="https://fwp.mt.gov/binaries/content/assets/fwp/education/literacy-program/healthy-dose-of-nature---evaluation.pdf">A Healthy Dose of Nature Worksheet</a> <P>
<b>7. PDF Article about animal migration -</b> <a href="https://fwp.mt.gov/binaries/content/assets/fwp/education/literacy-program/moving-right-along-article.pdf"><b>Moving Right Along</b></a> <P>
<a href="https://fwp.mt.gov/binaries/content/assets/fwp/education/literacy-program/moving-right-along-evaluation.pdf">Moving Right Along Worksheet</a> <P>
<b>8. PDF Article about monitoring wildlife numbers:</b> <a href="https://fwp.mt.gov/binaries/content/assets/fwp/education/literacy-program/tracking-wildlifes-ups-and-downs.pdf"><b>Tracking Wildlife’s Ups and Downs</b></a> <P>
The worksheet for this article can be found on this <a href="https://fwp.mt.gov/education/montana-outdoors-literacy-program">web page</a>.<P>
<b>9. PDF Article about Chief Plenty Coups -</b> <a href="https://fwp.mt.gov/binaries/content/assets/fwp/education/literacy-program/from-warrior-to-warrior-article---chief-plenty-coup.pdf">Warrior to Warrior</a><P>
<a href="https://fwp.mt.gov/binaries/content/assets/fwp/education/literacy-program/from-warrior-to-warrior---evaluation.pdf">Warrior to Warrior Worksheet</a> <P>
<b>10. PDF Article about beavers -</b> <a href="https://fwp.mt.gov/binaries/content/assets/fwp/education/literacy-program/beavers.pdf">Leave it to Beavers</a><P>
<a href="https://fwp.mt.gov/binaries/content/assets/fwp/education/literacy-program/beaversdone.pdf">Leave it to Beavers Worksheet</a> <P>
For a complete list, including several that were designed before I came on board (multiple-choice format), go to the <b><a href="https://fwp.mt.gov/education/montana-outdoors-literacy-program">Montana Outdoors Literacy Program</a></b>
Rod Bensonhttp://www.blogger.com/profile/07896836810905406697noreply@blogger.com0tag:blogger.com,1999:blog-5589900626143831959.post-10831544265004426982023-07-20T20:42:00.003-07:002023-07-20T20:50:54.509-07:00Blowdown in SW Montana - aftermath of 2019 Microburst<center><div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgZVtyLXul1KvCAJ4aDIRFXT08stiqAthC2PpJBX_f0-Xv2SkK3V_0b6KFS24Fp3_-tGs4Xfu-p38JhhVUn3IkorsybrMSi7l0qADVxA-Z2UGToySQdS6z6bG4ZkY0rn1wGUuC-rQYO5QuHsiovWBuxhEzN_8D4X62YA1XMDoX07q9GWy-svioKZkXz0xI/s1840/dji_fly_20230714_104304_45_1689353017620_photo-EDIT.jpg" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" width="600" data-original-height="1035" data-original-width="1840" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgZVtyLXul1KvCAJ4aDIRFXT08stiqAthC2PpJBX_f0-Xv2SkK3V_0b6KFS24Fp3_-tGs4Xfu-p38JhhVUn3IkorsybrMSi7l0qADVxA-Z2UGToySQdS6z6bG4ZkY0rn1wGUuC-rQYO5QuHsiovWBuxhEzN_8D4X62YA1XMDoX07q9GWy-svioKZkXz0xI/s600/dji_fly_20230714_104304_45_1689353017620_photo-EDIT.jpg"/></a></div></center><P>
<B>Microburst?</B><br>
On the afternoon of Sunday, August 11th 2019, a microburst occurred in the Tobacco Root Mountains of southwestern Montana, blowing down the estimated 200 to 250 acres of trees shown in the photo above. This blowdown resulted in the blockage of trails leading back to Granite Lake stranding 4 people in the backcountry due to trees blocking trails leaving the area. Personnel from the Madison County Search and Rescue, National Forest Service fire team, and two military helicopters were dispatched to the area to rescue those stranded in the backcountry.<P>
<B>The sky is falling!</b><br>
So, why do microbursts happen? Like tornadoes, lightning, hail, and flash floods, microbursts are associated with severe thunderstorms. They’re caused by the same cooling effect that happens when sweat evaporates from your skin. As sweat evaporates, it cools your body because the water molecules absorb (and remove) heat when they change from liquid to vapor. The same thing can happen in a thunderstorm. As rain or hail falls through very dry air, or the thunderstorm draws in dry air, much (or all) of the precipitation may evaporate (called sublimation when hail changes to vapor). Water molecules absorb heat from the surrounding air to make this phase change, making the air much colder. The more evaporation, the colder the air gets. Anyone who has opened a refrigerator door knows that colder air is heavier than warmer air. As this air (cooled by the evaporation of rain, or sublimation of hail) gets heavier, it plunges toward the ground like a lead weight. When the microburst reaches the ground surface winds may exceed 150 miles per hour – strong enough to blow fully grown pine trees over. Interestingly, the opposite phase change (vapor to snow) releases heat, contributing to the warming effect that causes Chinook winds.<P>
Watch this <a href="https://www.youtube.com/watch?v=7oKvgnzS3NQ"><b>1-minute video</b></a> of a microburst in Tucson, Arizona.<P>
<B>Mr. Tornado.</b><br>
Microbursts were discovered in the 1970s by tornado scientist Ted Fujita who developed the famous Fujita scale for rating tornado intensity. No doubt, you’ve heard of an F5 tornado – the ‘F’ stands for Fujita. The scale was revised several years ago – now called the ‘Enhanced Fujita Scale’ (EF0 – EF5). Fujita proposed that microbursts were for real, and suggested they were responsible for a number of mysterious aircraft crashes that had happened in the past during takeoff or landing beneath thunderstorms. Confirmation of his hypothesis ultimately led to a reduction in aircraft accidents and saving of lives.<P>
<B>Term:</b> sublimation<P>
For more about the area shown in the photo, go to <a href="https://bigskywalker.com/2023/07/15/blowdown-in-the-tobacco-roots-of-southwestern-montana/"><B>Bigskywalker.com</b></a>.Rod Bensonhttp://www.blogger.com/profile/07896836810905406697noreply@blogger.com0tag:blogger.com,1999:blog-5589900626143831959.post-71490370733588541602023-06-27T11:23:00.009-07:002023-06-27T11:46:23.410-07:001943 Smith Mine Disaster near Bearcreek, Montana - 75 men died<div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEizL_sJS7CHoI_AvUXL4dTmDQDQHEGvf2ZWhz8zBeceZ2GqShmUI5EybInVT1yCF3viUjmkOG_EefjNqBT1l1ls8k5JS_XUHdA_9VbHmE6PsBFKCgghsiBbkVS0P-rPPrTHCKg-4Gchspe5PCm2Oe4Y9bwS1cDKF_LwE9S9XoL0EAotHlKEmTf3bvtaOLY/s2614/IMG_2652.HEIC" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" width="800" data-original-height="1082" data-original-width="2614" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEizL_sJS7CHoI_AvUXL4dTmDQDQHEGvf2ZWhz8zBeceZ2GqShmUI5EybInVT1yCF3viUjmkOG_EefjNqBT1l1ls8k5JS_XUHdA_9VbHmE6PsBFKCgghsiBbkVS0P-rPPrTHCKg-4Gchspe5PCm2Oe4Y9bwS1cDKF_LwE9S9XoL0EAotHlKEmTf3bvtaOLY/s600/IMG_2652.HEIC"/></a></div><P>A sign posted along the highway a few miles east of Red Lodge tells of the disaster that happened at this mine in the winter of 1943 . . .<P>
Smoke pouring from the mine entrance about 10 o’clock in the morning of February 27, 1943, was the first indication of trouble. “There’s something wrong down here. I’m getting out,” the hoist operator called up. He and two nearby miners were the last men to leave the mine alive. Rescue crews from as far away as Butte and Cascade County worked around the clock in six-hour shifts to clear debris and search for possible survivors. There were none. The night of March 4, workers reached the first bodies. More followed until the toll mounted to 74. Some died as a result of a violent explosion in the No. 3 vein, the remainder fell victim to deadly methane gases released by the blast.<P>
The tragedy at Smith Mine became Montana’s worst coal mine disaster, sparking investigations at the state and national level. Montana Governor Sam C. Ford visited the scene, offered state assistance and pushed a thorough inquiry into the incident.<P>
The roadside sign that tells about of the disaster includes a message written by two of the miners trapped underground as they waited for the poisonous gas they knew would come.<P>
Good-bye wives and daughters. We died an easy death. Love from both of us. Be good.
Walter and Johnny.<P>
<B>The aftermath . . .</B><P>
Several weeks after the disaster, a coroner’s inquest involving witnesses and mine bureau investigators concluded that some of the men died from concussion caused by a gas and dust explosion, while others fell victim to gas poisoning. The disaster had a huge impact on nearby communities of Bearcreek, Washoe, and Red Lodge. Fifty-eight women lost their husbands and 125 children became fatherless, including six of eight students in the senior class at Bearcreek High School. The disaster brought an end to the local coal mining industry despite the fact that thousands of tons of coal remain beneath the arid hills. The towns of Bear
creek and Washoe all but vanished as homes were torn down, abandoned, or moved to nearby Red Lodge or Belfry. (source: Historian Bill Cenis, Town of Bearcreek)<P>
<B>Coal Use Then and Now . . .</B><P>
Today most of the coal used in the United States is burned to generate electricity, with the next biggest share used in the production of steel. At the time of the Smith Mine disaster, coal was not used to generate electricity, but it did have many other uses that were important to the American way of life. One of the primary uses was for heating homes and other buildings. Coal trucks made regular deliveries to houses that were kept warm by coal-burning stoves, often located in basements. Coal also fueled the smelters that removed copper and silver from ores mined in the western part of the state. Large quantities were also used to power the railroad trains that shipped goods and people across the country and coal was (is) used to make steel, especially important in WWII. Locomotives burned coal until 1950 when diesel engines replaced steam engines, causing a drastic decrease in the demand for coal at that time. Coal’s other early uses have gone by the wayside as well, replaced by cleaner burning, more efficient fuels. Today the demand for coal is kept high by the demand for electricity to run our iPods, cell phones, video games, computers, televisions and other electronic devices.<P>
<B>Coal Mining Then and Now . . .</B><P>
In the early 1900s there were many coal mines scattered in small towns across central and eastern Montana. Along with Bearcreek, Red Lodge, and Washoe, other communities such as Roundup, Klein, Belt, and Sand Coulee were also coal-mining towns. A big difference between coal mining in Montana at the time of the disaster and mining in recent decades is that “strip mining,” rather than underground mining, has been used to remove the vast majority of coal mined in Montana since 1970. With strip mining, layers of rock above the coal are removed to reach the seams of coal, and all of the work is done from the surface by large equipment operated by a few miners. Although it provides fewer jobs, strip mining is much safer because workers do not have to go underground where collapses, gas explosions, and lung diseadustses are risks.<P>
<B>Term:</B> dust explosion<P>
For more about the disaster, including an article + a great 4-minute video, <a href="https://www.ktvq.com/news/local-news/ghostly-site-smith-mine-a-haunting-legacy-of-a-montana-tragedy">CLICK HERE.</a>Rod Bensonhttp://www.blogger.com/profile/07896836810905406697noreply@blogger.com0tag:blogger.com,1999:blog-5589900626143831959.post-32651984421604662222022-08-23T12:48:00.004-07:002022-08-23T13:28:52.851-07:00Fun Density Demonstration<iframe width="560" height="315" src="https://www.youtube.com/embed/J1o3TtBLFKM" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>
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I show my students the demonstration, then ask them to estimate the densities of the four materials in the jar (room temp water, very salty water, ice, cold water). Hint: The room temp water has a density of 1 g/cubic cm. See instructions below.<P>
Make the ice cube by adding several drops of blue food coloring to water before freezing it in a styrofoam cup.<P>
To make the salty water, I added 190 mL of pickling salt (non-iodized) to 1 L water. FYI - Salty water made with iodized salt will be cloudy - not clear. <p>
Fill a jar half-way with tap-water, and let it sit to become room temp. To add the saltwater to the jar, use a tube and funnel. With the bottom of the tube positionede on the bottom of the jar, slowly pour the salty water in the funnel, forming the layer of very salty water below the room temp tap-water.Rod Bensonhttp://www.blogger.com/profile/07896836810905406697noreply@blogger.com0tag:blogger.com,1999:blog-5589900626143831959.post-40506296119107266022022-01-24T11:45:00.010-08:002022-01-25T09:29:36.701-08:00Tillite Found Among Pile of Erratics in North-Central Montana<div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/a/AVvXsEhoeq8KBSEShjSCAC3UzE7xUiuRFn4P1Tz3n6cTXCjoCogU7zr3ZONdWuvDfbXEdzh8fO2LzBtYbdOz7UNoqdvQOd1CNlLruOhwyW91No3e5G31ek8jP1x8bXdDx1nxQMm7fFRVhMCA80kaBVI4-cZdQHVfyui-dNn4FUzZ_BzrVzZ9ha18sV5gnEUg=s3513" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" width="600" data-original-height="2635" data-original-width="3513" src="https://blogger.googleusercontent.com/img/a/AVvXsEhoeq8KBSEShjSCAC3UzE7xUiuRFn4P1Tz3n6cTXCjoCogU7zr3ZONdWuvDfbXEdzh8fO2LzBtYbdOz7UNoqdvQOd1CNlLruOhwyW91No3e5G31ek8jP1x8bXdDx1nxQMm7fFRVhMCA80kaBVI4-cZdQHVfyui-dNn4FUzZ_BzrVzZ9ha18sV5gnEUg=s600"/></a></div>
This is a type of rock called “tillite” (a type of diamictite). Tillites consist of <u>poorly sorted</U>* pieces ranging in size from pebbles to boulders, embedded in a matirix of mudstone or sandstone. Meltwater from an ancient glacier somewhere in Canada likely deposited the rock material in a low place near the melting glacier. Over time it lithified (became rock), then was plucked away by a more recent ice sheet, transported to north-central Montana as the ice flowed into this area, and then finally dropped onto the ground when the ice melted. It was found in a pile of erratics on the Fort Belknap Reservation in north-central Montana (see photo below).<P>
*<u>Poorly sorted</U> means that the sediment contains a variety of different sizes of rock materials. River systems tend to sort rock materials according to size by typically depositing larger pieces (gravels) first in valleys, sand-sized pieces next near shorelines, and finally smaller silts and clays in deeper water environments. In contrast, glaciers simply drop whatever pieces they contain where the ice melts – no matter the size. This unsorted rock material is referred to as till.<p>
<b>Below:</b> This pile of erratics is where the tillite shown above was found. Erratics are rocks that have been transported from another area by glaciers. Most of these are metamorphic rocks that came from the Hudson Bay area of Canada. A farmer placed them in this pile just west of Three Buttes (in backgroud), which is located in north-central Montana.<P><div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/a/AVvXsEjFGE9p7w0uKW9XY6MFJPmDAs7QgqHz__2UbNxRHPeVZ_vw4u8k538JAJ9UqdhH_Ga3v24rF8M8l0SHJIhJO9Hfik9DrbXdbhYjNi1iIXoY0TUyDPLCTN43RvVrMpwESyl73D94FxQh5yJWw3_GRoRdo8uXruIoPkpl1mQFcSBhHysXKq3Iw7yaO78v=s5323" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" width="600" data-original-height="2197" data-original-width="5323" src="https://blogger.googleusercontent.com/img/a/AVvXsEjFGE9p7w0uKW9XY6MFJPmDAs7QgqHz__2UbNxRHPeVZ_vw4u8k538JAJ9UqdhH_Ga3v24rF8M8l0SHJIhJO9Hfik9DrbXdbhYjNi1iIXoY0TUyDPLCTN43RvVrMpwESyl73D94FxQh5yJWw3_GRoRdo8uXruIoPkpl1mQFcSBhHysXKq3Iw7yaO78v=s600"/></a></div>Rod Bensonhttp://www.blogger.com/profile/07896836810905406697noreply@blogger.com0tag:blogger.com,1999:blog-5589900626143831959.post-55347284882033218322021-11-11T19:43:00.007-08:002021-11-13T06:15:33.344-08:00Glacial Polish on the Fort Belknap Reservation in Montana<div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjUoC4hYddMapKvHUUI7aSacqZJrBVQp7FMYbtJ2U6Se6bHnLJ6UABHzpwvAXw5E9YYP-IhHRKSn9zuMghHy4rih1TwQKssaJJrC9gv_DH07EhoPe5YcjCGSnP5Wp-tRl0d2V2Ce57q0Sd8/s2048/EPoDsmooth.jpg" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" width="600" data-original-height="1793" data-original-width="3245" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjUoC4hYddMapKvHUUI7aSacqZJrBVQp7FMYbtJ2U6Se6bHnLJ6UABHzpwvAXw5E9YYP-IhHRKSn9zuMghHy4rih1TwQKssaJJrC9gv_DH07EhoPe5YcjCGSnP5Wp-tRl0d2V2Ce57q0Sd8/s600/EPoDsmooth.jpg"/></a></div><P><B>Above:</b> Drone photo of me walking across an interesting outcrop - November 2021. Click on photo to enlarge.<P>The smooth surface of this outcrop of igneous rock in northcentral Montana is a great example of glacial polish. As the Laurentide Ice Sheet flowed across here thousands of years ago, the abrasive action of pebbles and sand stuck to the glacier's underside smoothed the surface and rounded the jagged edges. The outcrop is located near the southwest edge of Snake Butte, an impressive plutonic formation (laccolith) located on the Fort Belknap Reservation.<P>
Subtle grooving in the rock prove that the ice moved across here was flowing toward the southeast. Other evidence, including distinct striations on another part of Snake Butte and a 50-mile long boulder train, confirms this. The southeastery flow was due to the influence of the nearby Bears Paw Mountains, which changed the glacier's flow from southward to southeastward.<P>
<a href=https://bigskywalker.com/2017/11/04/snake-butte-in-north-central-montana/><b>CLICK HERE</B></a> to learn much more about Snake Butte, including all about the Snake Butte Boulder Train.<P>
<B>Terms: </b> abrasion, plutonic formation
Rod Bensonhttp://www.blogger.com/profile/07896836810905406697noreply@blogger.com0tag:blogger.com,1999:blog-5589900626143831959.post-85030833408667111052021-10-26T11:07:00.005-07:002021-10-26T11:07:47.828-07:00Ancient Ash in the Missouri Breaks of Central Montana<div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjk6CjIbDd1mH9IRq0yjbLMbZ7Pa5Rd_b02_IpdwjMvwbWDEEbxX7lGi8jL7ocK60r4N2bPuYkjVTWANQEw9BOkrMzrtc2CTen9EEPM5aAaZVyKPtHbXlr1b_Krr8gjKNFylabkstZfT7Y/s2048/EPODbearpawash.jpg" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" width="660" data-original-height="1501" data-original-width="2048" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjk6CjIbDd1mH9IRq0yjbLMbZ7Pa5Rd_b02_IpdwjMvwbWDEEbxX7lGi8jL7ocK60r4N2bPuYkjVTWANQEw9BOkrMzrtc2CTen9EEPM5aAaZVyKPtHbXlr1b_Krr8gjKNFylabkstZfT7Y/s600/EPODbearpawash.jpg"/></a></div><p>
<B>Not a fossilized highway.</B><br>This photo was taken along an intermittent tributary of the Missouri River in the Missouri Breaks region of central Montana. The sediments exposed in the cut bank are part of the Bearpaw formation (aka Bearpaw shale). The silts and clays were deposited in the Western Interior Seaway, an inland sea that extended from the Arctic to the Gulf of Mexico during the mid to late Cretaceous period. The part of the sea that covered this part of Montana is sometimes called the Bearpaw Sea, named for the Bears Paw Mountains located 60 miles northwest of here. <P>
Over millions of years the sea advanced and retreated across the region, changing the location of the shoreline and the depth of the water. In the meantime, occasional volcanic eruptions to the west spewed ash that winds carried over the sea. The thicker light-colored layer in the photo is ash from one of those eruptions. A few thinner deposits of ash are also exposed in the cut bank. Volcanic ash deposited in seawater changes over time; weathering converts it into a clay material called bentonite. Although it looks like ash from a distance, it feels like a sticky clay that has little resemblance to the ancient ash that settled here. <P>
In addition to bentonite (altered ash) the Bearpaw formation contains a variety of marine fossils and some dinosaurs. Geologists estimate that sediments of the Bearpaw formation were deposited between 75 and 72 million years ago. In places the formation is 350 meters thick. Outcrops can be found in Montana as well as the Canadian provinces of Alberta and Saskatchewan. As the Western Interior Seaway retreated to the southwest, the Bearpaw shales were covered by deltaic and coastal plains sediments. <P>
<b>Terms:</b> intermittent, deltaic sediments
Rod Bensonhttp://www.blogger.com/profile/07896836810905406697noreply@blogger.com0tag:blogger.com,1999:blog-5589900626143831959.post-87244065351799001802021-10-21T07:53:00.007-07:002021-10-23T12:18:57.089-07:00The Belt Meteor Crater - NOT!
<div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjMV0IB-Dq9MfJx1cuXK8Ddb30lCQicz42pIRaowh7QsuDL91uSPdiqMldGSrVAA5_6aKEUyA1IsObmfN_ZizePL7zToLs3OwjnRtpBaFRXCBfbjjG6mTCMvuSz7W-I9M99HD70eODn7ok/s2048/EPODcrater.jpg" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" width="726" data-original-height="1394" data-original-width="2048" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjMV0IB-Dq9MfJx1cuXK8Ddb30lCQicz42pIRaowh7QsuDL91uSPdiqMldGSrVAA5_6aKEUyA1IsObmfN_ZizePL7zToLs3OwjnRtpBaFRXCBfbjjG6mTCMvuSz7W-I9M99HD70eODn7ok/s600/EPODcrater.jpg"/></a></div><p>
FYI - I took this photo with a drone. That is me standing on the other side of the crater.<P>
<b>Wrong name.</b><br>The Belt Meteor Crater, which is located on private land in central Montana, was NOT made by a meteorite slamming into the prairie. It is actually a sinkhole, caused by the dissolution of limestone beneath the surface. The rim of the crater is made of sandstone, but a thick (up to 1700 feet) formation called the Madison limestone underlies the area. As water soaks down through soils above, it becomes slightly acidic. Then as this water works its way down through cracks, it dissolves away the limestone, forming caves. The sinkhole is 100 feet across and 40 feet deep, so a fairly large cave must have formed in the limestone not far beneath the surface here. Eventually the layers of sandstone above the cave collapsed onto the cavern floor to form the sinkhole.<P>
<b>Kill Site.</b><br>The Belt Meteor Crater once served as a buffalo jump, or "pishkun", for Native Americans as evidenced by bison bones and arrowheads on the floor of the hole. "Pishkun" is Blackfeet for "deep blood kettle." Scientists visited the sinkhole to collect bison bones that can be carbon-dated to determine when Indians used it. They also found an arrowhead(s) made of obsidian. Experts can determine where the obsidian came from by comparing its mineral composition with obsidian outcrops in the region. This can help provide insights about Native American trade routes. <P>
<b>Term:</b> dissolution<p>
<a href="https://www.insurancejournal.com/img/articles/fl-sinkhole-map.jpg" target="_blank">Map of sinkholes in Florida</a> - May home-owners in Florida actually buy sinkhole insurance!
<P>
<a href="https://photos.app.goo.gl/Z7RVDNW3srnEhq377" target="_blank">More photos of the Belt Meteor Crater</a> (Google Album)
<P>
<a href="http://bigskywalker.com/" target="_blank">Bigskywalker.com</a> - lots of geology
<P>
Rod Bensonhttp://www.blogger.com/profile/07896836810905406697noreply@blogger.com0tag:blogger.com,1999:blog-5589900626143831959.post-8002885631173416272021-04-04T20:16:00.009-07:002021-04-14T06:06:03.207-07:00Limestone wall around the Little Rockies in north-central Montana<div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgx4bnENM6ZRL0ibXkRQhHSzSI6IfxRh9Z6a-JsrMYrEAmUSUseiRR6B5He9Eg6SFwztqRhDlviNsY8jSYI0g3W2xSojw3F_UmBN_j6laLpKNoP4frRAzGrSlGpzqAzCH27r5mfKimkWZA/s2048/EPODbenson.jpg" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" width="800" data-original-height="1365" data-original-width="2048" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgx4bnENM6ZRL0ibXkRQhHSzSI6IfxRh9Z6a-JsrMYrEAmUSUseiRR6B5He9Eg6SFwztqRhDlviNsY8jSYI0g3W2xSojw3F_UmBN_j6laLpKNoP4frRAzGrSlGpzqAzCH27r5mfKimkWZA/s600/EPODbenson.jpg"/></a></div>
<p><strong>Above:</strong> I took this drone photo of myself (blue shirt) during a recent hike in the Little Rockies of north-central Montana.<P>
<P><strong>Tropical Montana</strong><br>These cliffs are made of nearly vertical layers of Madison limestone, formed from sediment that was deposited during the Mississippian Period 320-360 million years ago. Thick deposits of corals, shells, and other forms of calcium carbonate accumulated on the floor of a shallow tropical sea when this part of Earth’s crust was much closer to the equator. The Madison limestone makes a major contribution to the scenery of Montana - The Gates of the Mountains, the Rocky Mountain Front, Lewis and Clark Caverns, Sluice Boxes, and Bighorn Canyon are all made of (entirely or partially) Madison limestone.</p>
<p><strong>The rest of the story.</strong><br>The sediment was deposited in horizontal layers, eventually became rock, and was covered by younger layers, which also became rock (sandstones and shales). Then about about 60 million years ago magma worked its way toward the surface, causing the layers to be domed upward. The magma hardened, becoming the igneous rock found at the core of the mountain range. The doming occurred in an area about 15-20 miles in diameter. Over time, most of the limestone and other layers above the igneous intrusion eroded away, leaving only the steeply-tilted perimeter of the limestone dome that forms the cliffs shown in the photo and other similar outcrops around the perimeter of the Little Rockies.<P>
For more about the cliffs, go to <a href="https://bigskywalker.com/2021/04/02/wall-walk-in-the-little-rockies-northcentral-montana/"><B>Bigskywalker.com</b></a>
Rod Bensonhttp://www.blogger.com/profile/07896836810905406697noreply@blogger.com0tag:blogger.com,1999:blog-5589900626143831959.post-18044136284769808702019-09-21T07:42:00.000-07:002019-09-21T15:25:02.165-07:00Mission Reservoir in Western Montana - A Moraine-Dammed Lake<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgF6KIht_L_oZPEXs6eGQ8gULxJlxjF0HhPZFLnoesBk9HlYyq7OPJ3UCTde1dbu7WZFLH12uk3n2fwX39-X1W980MAE89GEPBLmSLYM7xHjTyL47gEnX65HXbde6Uh40gfqXAYoyy5JMc/s1600/MoraineMissionRes.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgF6KIht_L_oZPEXs6eGQ8gULxJlxjF0HhPZFLnoesBk9HlYyq7OPJ3UCTde1dbu7WZFLH12uk3n2fwX39-X1W980MAE89GEPBLmSLYM7xHjTyL47gEnX65HXbde6Uh40gfqXAYoyy5JMc/s640/MoraineMissionRes.jpg" width="680" height="340" data-original-width="1600" data-original-height="800" /></a></div><P>
This is Mission Reservoir in western Montana - about 50 miles north of Missoula. St. Ignatius (pop. 842) can be seen in the distance. The reservoir is actually a moraine-dammed lake formed by a valley glacier during the last ice age. It has been modified to serve as a reservoir. <div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiUuRnp5G6-xqcL5nmQx5_FmFUJJ5dOqcg_losFUT3cY3JYfVh8P5tTFNnZqMx_-v3IxntEhTQ35lyew7Q1OqVVCY7otuP0DRKaTz6_0XfXuENcDHnTOW_TElpALvZO7sEhAuSjc_Q3GSQ/s1600/moraine.jpg" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiUuRnp5G6-xqcL5nmQx5_FmFUJJ5dOqcg_losFUT3cY3JYfVh8P5tTFNnZqMx_-v3IxntEhTQ35lyew7Q1OqVVCY7otuP0DRKaTz6_0XfXuENcDHnTOW_TElpALvZO7sEhAuSjc_Q3GSQ/s320/moraine.jpg" width="320" height="212" data-original-width="458" data-original-height="304" /></a></div><P>
The “lateral moraines” were deposited along the sides of a valley glacier (a.k.a. "alpine glacier") during the last ice age. The moraines are the curved ridges along the sides of the reservoir. These forested ridges consist of rock material that the glacier removed from the mountains in the upper part of the drainage basin, high above the lake. Over the thousands of years since the moraine was formed, soil has formed on top and trees have taken root. <P>
<B>Right:</b> Aerial photo of Mission Reservoir taken several years ago by Lawrence Dodge of Big Sky Magic Enterprises.<p>
<B>Below:</b> This is similar to what the Mission Reservoir area probably looked like at the height of the last ice age ~20,000 years ago.<P>
Rock material that has been transported and deposited by glaciers is called "till". As the glacier formed, rocks became stuck to its bottom and sides. Then as the ice flowed toward the valley floor, these rocks scoured away even more of the mountain’s surface. The glacial ice flowed to the position marked by the location of lake where it melted and dropped the rocks. For thousands of years, snowfall continued to replace the ice as it flowed away from the mountain tops. This "conveyor belt" took much of the mountain with it, forming the moraines. Much of the till deposited at the end of the glacier was washed away as the ice melted, so some of the original "end moraine” is missing. Since the end of the last ice age (10,000 years ago), soil has developed on the moraines and trees have taken root.<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEicNbSMhhGNRc6xn3lB8JIZZDJE2rI7Y_LXKdyD7I1tHDlHo_nlFrsrEzloghZkSZlugZMem-YS_RiQQ3UTUsJHv7tlIVvylfhK8HQK2KMk8n-_Zo38eR_IbY0Gx0DrWfVN5ohis8-CTGQ/s1600/moriane.jpg" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEicNbSMhhGNRc6xn3lB8JIZZDJE2rI7Y_LXKdyD7I1tHDlHo_nlFrsrEzloghZkSZlugZMem-YS_RiQQ3UTUsJHv7tlIVvylfhK8HQK2KMk8n-_Zo38eR_IbY0Gx0DrWfVN5ohis8-CTGQ/s320/moriane.jpg" width="320" height="214" data-original-width="364" data-original-height="243" /></a></div><P><P>
Geologists describe till as “unsorted” because it is made up of all sizes of rocks. This characteristic helps geologists distinguish materials deposited by glaciers from those deposited by running water, which tends to deposit different sizes of rocks in different areas.<P>
<b>Related Links . . . </b><P>
<b>1. </b><a href=https://bigskywalker.com/2019/09/16/east-and-west-st-marys-peaks-on-the-flathead-reservation/><b>CLICK HERE</b></a> to access the blog post and photo tour of the hike I did to get the photo of Mission Reservoir.<P>
<b>2. </b><a href=https://vimeo.com/51463241><b>CLICK HERE</b></a> to watch a 3-minute drone video of the Mission Reservoir.<P>
<b>3. </b><a href=http://www.morainecampaign.org/><b>CLICK HERE</b></a> to see a nice photo of Lake Wallowa in northeastern Oregona - another great example of a moraine-dammed lake.<P>
Rod Bensonhttp://www.blogger.com/profile/07896836810905406697noreply@blogger.com1tag:blogger.com,1999:blog-5589900626143831959.post-73826102085513510372019-07-29T19:08:00.002-07:002019-07-31T06:05:37.365-07:00Borah Peak Fault Scarp in Idaho formed during 1983 Quake<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjZnLBsTi3K6qOJHJTurBgSxKFCR_lnTr3cnY8qxWezzeIzQVeJ0Sds1bwOkOm5EhTQVqKVF6T9jJqAW-it4YpZ2_rQvOckQag20qbs7KyO3oFKlcsLEoumWliklmt86z0IfOZlOxc4dc8/s1600/aaScarpEPOD.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjZnLBsTi3K6qOJHJTurBgSxKFCR_lnTr3cnY8qxWezzeIzQVeJ0Sds1bwOkOm5EhTQVqKVF6T9jJqAW-it4YpZ2_rQvOckQag20qbs7KyO3oFKlcsLEoumWliklmt86z0IfOZlOxc4dc8/s640/aaScarpEPOD.jpg" width="640" height="320" data-original-width="1600" data-original-height="800" /></a></div><P>
The thin tan line in this photo is the Lost River Fault Scarp, which runs for over 20 miles along the base of the Lost River Range in central Idaho. The scarp formed as result of a 6.9 M earthquake that occurred at 8:06 am on October 28, 1983. The quake was named the “Borah Peak Earthquake” because it happened near Borah Peak (12,662 ft.), the highest mountain in Idaho - the one on the left in this photograph. The photo was taken along the road to the Birch Springs Trailhead where hundreds of hikers come every year to begin their ascent of Borah (known locally as Mt. Borah). <P>
The Lost River Range is a fault-block mountain range on the northeastern edge of the Basin and Range Province. Like Basin and Range Mountains in other states such as Utah and Nevada, these mountains formed one earthquake at a time over millions of years. During the 1983 quake the valley side of the fault dropped 9 feet and the block that includes the Lost River Range rose 6 inches, leaving the offset (scarp) shown in the photos. <P>
The epicenter was located along the fault somewhere between the small towns of Mckay and Challis. Although it was the most energetic earthquake in the lower 48 since the 1959 Hebgen Lake Earthquake in southwestern Montana, there were only two deaths. Two children (ages 6 and 7) were killed in Challis when a brick wall collapsed on them as they walked to school. Shaking was felt in eight states and two Canadian provinces, lasting from 30-60 seconds.<P>
<P><b>Below:</b> This photo, taken by Bruce Railsback of the University of Georgia, shows a person standing below the Lost River Fault Scarp (near bottom, center of photo). Bruce took the photo in in 1987, four years after the earthquake happened.<P><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgyzcfTI9ChAuqHxPbL1u6s0MKDoDApE39hhJlCmh_mNGse3gawRSw9DPicgAtsIMr8q-CKLo0J5f1UFEcJqyOsozb26n6xh5Nm-ww4kX1TyPQEZiMLxyJnM1DsjLYSm6sXlPyIyvtG8Kg/s1600/aaaLostRiverFaultScarp87.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgyzcfTI9ChAuqHxPbL1u6s0MKDoDApE39hhJlCmh_mNGse3gawRSw9DPicgAtsIMr8q-CKLo0J5f1UFEcJqyOsozb26n6xh5Nm-ww4kX1TyPQEZiMLxyJnM1DsjLYSm6sXlPyIyvtG8Kg/s640/aaaLostRiverFaultScarp87.jpg" width="640" height="247" data-original-width="898" data-original-height="347" /></a></div><P>
<b>Links . . . </b><p>
<a href=https://nisquallyquake.files.wordpress.com/2010/01/borah.jpg><b>Newspaper coverage by the Idaho Statesman</b></a><P>
<a href=https://en.wikipedia.org/wiki/Basin_and_Range_Province><b>Basin and Range Province (Wikipedia)</b></a><P>
<a href=https://bigskywalker.com/2019/07/24/mt-borah-the-highest-peak-in-idaho/><b>Climbing Mt. Borah (aka Borah Peak)</b></a><P>
<a href=https://en.wikipedia.org/wiki/Fault_block#Fault-block_mountains><b>Fault-Block Mountains (Wikipedia)</b></a>
Rod Bensonhttp://www.blogger.com/profile/07896836810905406697noreply@blogger.com1tag:blogger.com,1999:blog-5589900626143831959.post-37741103072760416322019-05-25T20:16:00.002-07:002019-05-26T07:50:17.462-07:00Animation of the Night Sky at Your Location<a href=https://www.timeanddate.com/astronomy/night/><b>CLICK HERE</b></a> to go to Timeanddate.com, set the site to your location (or a nearby city), scroll down to the "Night Sky Map", select a planet to watch, and then click on the play arrow (or FFWD arrow, or scroll bar). You can pause and scroll over stars or other planets to see their names. Pretty dang cool if you ask me! The site provides plenty of other interactive astronomy animations to fiddle around with as well.<P>
<B>Below:</b> This screen shot is an example of what you will see - except it will be in motion. NOTE: The site resets at noon every day, so the best time to check is afternoon.<P>
<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjf4xeZYX2BGFu5_0jMoJmIqbe41tNLYx1_ZPqYOEZmsVoMThVfdpCj2GniIuEO3XQX1dJ-3TOgzJN25BmookDjL0xeEMZI8B73Hte9LKSWdZ9S0JdjAFZYHwBPar8duY61FfW8I1gpTeU/s1600/timeanddate.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjf4xeZYX2BGFu5_0jMoJmIqbe41tNLYx1_ZPqYOEZmsVoMThVfdpCj2GniIuEO3XQX1dJ-3TOgzJN25BmookDjL0xeEMZI8B73Hte9LKSWdZ9S0JdjAFZYHwBPar8duY61FfW8I1gpTeU/s640/timeanddate.png" width="640" height="368" data-original-width="910" data-original-height="523" /></a></div>Rod Bensonhttp://www.blogger.com/profile/07896836810905406697noreply@blogger.com10tag:blogger.com,1999:blog-5589900626143831959.post-23047249610422903702019-05-16T12:28:00.002-07:002019-05-17T05:48:03.218-07:00Draw the orbits of the planets on your city.
This is a really cool way to help students understand the size of the solar system. Go to <a href=https://umanitoba.ca/observatory/outreach/solarsystem/><B>this website</b></a>, and center the map on your city. This can be done entering your latitude and longitude, or you can expand the map* to full screen and then manipulate it so that your city is at the center. Then enter "33223 mm" for the diameter of the Sun - This is how big the Sun would be if the Earth were the size of a standard globe (12 inches in diameter). Finally, select "calculate" and "show orbits". <P>
*If you expand the map to "full screen" you will need to get out of "full screen" to enter the diameter of the Sun.<P>
<b>Below:</b> To see where the planets are right now, go to <a href=https://www.fourmilab.ch/cgi-bin/Solar/action?sys=-Sf><b>this website</B></A>.<P>
<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiB7pO9E_YPGz76w1KBcZxLQxIJEaanKX1d3eH9aFXsRluWuErvdEf6PRN3dI396o6fujeqXIHFquw6z3C8U9ogGZBKF400J3Z3lBNvjJcOfsTuWIz4DhVmVhhmtAdOHMmgUXSVBWIbE1A/s1600/now.gif" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiB7pO9E_YPGz76w1KBcZxLQxIJEaanKX1d3eH9aFXsRluWuErvdEf6PRN3dI396o6fujeqXIHFquw6z3C8U9ogGZBKF400J3Z3lBNvjJcOfsTuWIz4DhVmVhhmtAdOHMmgUXSVBWIbE1A/s1600/now.gif" data-original-width="800" data-original-height="800" /></a></div>
Rod Bensonhttp://www.blogger.com/profile/07896836810905406697noreply@blogger.com7tag:blogger.com,1999:blog-5589900626143831959.post-66293620941354351652019-03-23T10:27:00.002-07:002019-03-23T11:52:55.611-07:00Losing Ground - a documentary about urban sprawl Maybe we (Earth Science teachers) should spend more time teaching students about soil (the forgotten natural resouce) and help students understand this issue. We lose 175 acres of land to urban sprawl every hour! The documentary will premiere on May 27,2019 and then will be available on the "Angus TV" YouTube Channel after that - Mark your calendar.<P><center><iframe width="560" height="315" src="https://www.youtube.com/embed/suAlYGyzfNs" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe></center>Rod Bensonhttp://www.blogger.com/profile/07896836810905406697noreply@blogger.com0tag:blogger.com,1999:blog-5589900626143831959.post-72462402585522379672019-03-01T19:39:00.001-08:002019-03-04T05:23:29.617-08:00Kelvin-Helmholtz Clouds Caused by Wind Shear<center><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj6pNpQhb5mhGvqoWRQLI9JsM8XRDbv2-mGGGDn_9i14D5Vlu6aGQS8LZXqUhiRB8F_ikEMc-SpVWqhMi69vnwpduWL6dzJh8Amy_7NJ4MXWtpLQgEjWJTULUYX4VoW362R47bRKIiAWaC4/s1600/EPODclouds.jpg" imageanchor="1" ><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj6pNpQhb5mhGvqoWRQLI9JsM8XRDbv2-mGGGDn_9i14D5Vlu6aGQS8LZXqUhiRB8F_ikEMc-SpVWqhMi69vnwpduWL6dzJh8Amy_7NJ4MXWtpLQgEjWJTULUYX4VoW362R47bRKIiAWaC4/s640/EPODclouds.jpg" width="640" height="320" data-original-width="1600" data-original-height="800" /></a><P></center>
<b>The right place, at the right time.</b><br>
This photo of an amazing Kelvin-Helmholtz cloud was taken on January 26, 2019 by Hannah Martin, one of my freshman Earth Science students at Helena High School. She snapped the photo from the Helena Valley, looking west - Mount Helena can be seen on the left, and the distant horizon marks the Continental Divide. Also known as "fluctus" or "billow" clouds, they were named after Lord Kelvin (1824-1907) and Hermann Von Helmholtz (1821-1894) who identified the type of instability responsible for the unique waves. Such clouds are fairly rare, and may only last for a few minutes.<P>
<b>Like wind across water.</B><br>
The waves form at the boundary between layers of air that have different densities and wind speeds (wind shear). Air in the layer above the cloud is moving faster than air in the layer containing the cloud. Development of waves on the cloudy layer is similar to what happens when waves form on the ocean as wind blows across the water. In the photo the wavy layer is more dense than the clear air flowing above it - just as water is more dense than air blowing over its surface.<P>
<b>Clouds provide a "visual".</b><br>
The type of motion that causes the wave pattern is actually not that uncommon in the atmosphere, although we usually don't see it. In order for us to see it, clouds must be present in the lower layer (as they were when the photo was taken). We can't see clear air, but we can see clouds. One of the nice things about clouds is they provide clues about the type of motion currently happening in the atmosphere. Want to know more? - Watch the 4.5-minute video below, which includes a great demo.<P>
<b>Term for students to define:</b> wind shear<P>
<a href=https://www.abc.net.au/news/2018-11-06/pilots-can-ride-alongside-breakers-in-the-atmosphere/10469280><b>1. Article - More about KH Clouds</b></a><P>
<a href=https://www.thoughtco.com/kelvin-helmholtz-clouds-3443792><b>2. Another good article about KH Clouds</b></a><P>
<center><iframe width="560" height="315" src="https://www.youtube.com/embed/qgamfo86FQo" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe></center>Rod Bensonhttp://www.blogger.com/profile/07896836810905406697noreply@blogger.com12tag:blogger.com,1999:blog-5589900626143831959.post-42481797217548095912019-01-18T22:12:00.001-08:002019-01-18T22:36:10.346-08:00Check out the Lunar Eclipse on Sunday, January 20th.The eclipse will start at 7:36 pm MST, and will about 5 hours from start to finish. Hopefully it will be clear where you live! To find out more about the timing, etc., here are a couple resources . . . <P>1. Go to <a href=https://www.timeanddate.com/eclipse/globe/2019-january-21><b>timeanddate.com</b></a> and enter your location.<P>2. Read how to watch at <a href=https://www.theverge.com/2019/1/18/18186751/total-lunar-eclipse-super-blood-wolf-moon-january-20><b>theverge.com</b></a>.<P>
The video below is not specific to the eclipse of January 2019, but it does an nice job of explaining different aspects of lunar eclipses. <P>
<iframe width="560" height="315" src="https://www.youtube.com/embed/lNi5UFpales" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>Rod Bensonhttp://www.blogger.com/profile/07896836810905406697noreply@blogger.com0tag:blogger.com,1999:blog-5589900626143831959.post-89133550419932828352019-01-16T10:08:00.000-08:002019-01-16T10:08:55.139-08:00Enter your address to see where you would have been millions of years ago.This is <a href=http://dinosaurpictures.org/ancient-earth#0><b>a fantastic interactive visualization</b></a> that was created (and is maintained) by Ian Webster. Once the site opens, enter your address in the box in the upper left, then select the time (in Earth's history) near the top of the web page. To see more of Ian's work, go to <a href=http://www.ianww.com/><b>ianww.com</b></a>.<P>
Thanks to Rick Dees for showing me this!<P>
<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh-K25RJa4vCCTWZwuYbF-CFZEifeKwirRdDEsIew7FAS5u5C2gk9rTnxjSVAM6mTMg-ZxHYSz-WkSVYQ8VK-_o8iJqInv9BlDFt1DPUUPrSxNRcNIUmr5XN9xATLMkvavptHS4N__Cn64/s1600/PaleoEarth.jpeg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh-K25RJa4vCCTWZwuYbF-CFZEifeKwirRdDEsIew7FAS5u5C2gk9rTnxjSVAM6mTMg-ZxHYSz-WkSVYQ8VK-_o8iJqInv9BlDFt1DPUUPrSxNRcNIUmr5XN9xATLMkvavptHS4N__Cn64/s640/PaleoEarth.jpeg" width="640" height="360" data-original-width="1150" data-original-height="647" /></a></div>
Rod Bensonhttp://www.blogger.com/profile/07896836810905406697noreply@blogger.com2tag:blogger.com,1999:blog-5589900626143831959.post-56035015638559967492018-12-13T13:57:00.000-08:002019-03-01T19:53:12.430-08:00Classic Chinook Arch over Helena, Montana<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi4H1pP7_3EIDBbiAbGpdjszXiZ5i44YfaWkkUpoM4ngoWCCMrmbS_8WPXQMIAHQ3w9a_bg_zgo2pbdZ5uQMQ-GtpUAzNptM9BrtWtaSvm-DkRww8YSDav1_YCL46g0uBChMdvaCDasuDs/s1600/arch1500b.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi4H1pP7_3EIDBbiAbGpdjszXiZ5i44YfaWkkUpoM4ngoWCCMrmbS_8WPXQMIAHQ3w9a_bg_zgo2pbdZ5uQMQ-GtpUAzNptM9BrtWtaSvm-DkRww8YSDav1_YCL46g0uBChMdvaCDasuDs/s640/arch1500b.jpg" width="768" height="180" data-original-width="1500" data-original-height="352" /></a></div><P>
<b>A Mountain Wave.</b><br>
This photo was taken from the Helena High athletic fields, looking west toward the Continental Divide. It shows the classic Chinook arch that appeared on December 13, 2018. The clear area between the arch and the mountains exists because the air is down-sloping there. As air flows over the Rockies it may develop an up and down motion like water flowing over rocks in the rapids of a river. Although the air flows downward once it gets over the mountains, it may continue to oscillate up and down as it flows away from the mountains for several hundred miles. The upward flowing part of this "mountain wave" is what forms the long arch of clouds. (Click on the image to enlarge it or <a href=https://vimeo.com/306235071><b>CLICK HERE</B></a> to watch a 24-second video of the arch shown in the photo.)<P>
<b>Here's how it works.</b><br>
As the air flows down-slope, it is warmed by compression. Then, as the wave action continues and the air begins to rise again, the air cools by expansion. If there is enough vapor in the air, the arch of clouds will form as vapor condenses to form cloud droplets (or cloud crystals). Typically, the long area of clouds will form near the crest (top) of the first wave and then get blown eastward by higher level winds. If the mountain wave continues, and another downward turn is taken, the arch (cloud) will evaporate farther downstream (east).<P>
<b>Same arch, different vantage point.</b><br>
The G.O.E.S. East satellite image below shows what the same Chinook arch looked like from space at 9:47 am MST. It is called an "arch" because an observer standing below it sees a curved patch of clear sky between the band of clouds and the mountains below. In the satellite image, the Chinook arch is the distinct eastern edge of the bright white cloud that extends from north to south through western Montana.<P><P>
<b>Term to define:</b> GOES East Satellite<P>
<b>Confused?</b> - Check out this <a href=https://www.greatfallstribune.com/story/news/local/2016/10/20/wave-wind-creates-chinook-arch-east-rockies/92445270/><b>Great Falls Tribune article</b></a>.<P>
<center><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjMZ7dIZ89AqfHY4xGPQRTE0ycIRDBVl1PlAm4gM441h29Jw2LLdSM2NYamkfoMsc3dujXl_42nszLC5Je2fKNsqXV35wIM4VyyUCI9R4mq4fppDnyCBVKTKmdMxYiJVRQnier1i09_7L4/s1600/arch7.jpg" imageanchor="1" ><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjMZ7dIZ89AqfHY4xGPQRTE0ycIRDBVl1PlAm4gM441h29Jw2LLdSM2NYamkfoMsc3dujXl_42nszLC5Je2fKNsqXV35wIM4VyyUCI9R4mq4fppDnyCBVKTKmdMxYiJVRQnier1i09_7L4/s640/arch7.jpg" width="640" height="640" data-original-width="600" data-original-height="600" /></a></center>
Rod Bensonhttp://www.blogger.com/profile/07896836810905406697noreply@blogger.com0tag:blogger.com,1999:blog-5589900626143831959.post-12001252841580030522018-12-05T09:12:00.002-08:002018-12-05T09:12:09.283-08:00Make a cloud with your mouth!This is the coolest activity I've seen in awhile - Lots of good science, and explained very well. Check it out.<P><iframe width="560" height="315" src="https://www.youtube.com/embed/68A_Azsqqg4" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>Rod Bensonhttp://www.blogger.com/profile/07896836810905406697noreply@blogger.com1tag:blogger.com,1999:blog-5589900626143831959.post-56123870052876083722018-11-07T21:19:00.000-08:002018-11-10T15:18:33.916-08:00Mazama Ash in Montana
<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjTlHszW2dVUPnGAYNOEowaadcbzgRjFXwHpkE65RHqP3Nynzhz0_xUvi3BzBZ8qHYtFgAFE1ivjPdlmUXuZC4SJC8h3DDUX37lMX-dNInnUazI6y5fG2zybfdeFQMrmPYCyJC8CShx9ug/s1600/ash.jpg" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjTlHszW2dVUPnGAYNOEowaadcbzgRjFXwHpkE65RHqP3Nynzhz0_xUvi3BzBZ8qHYtFgAFE1ivjPdlmUXuZC4SJC8h3DDUX37lMX-dNInnUazI6y5fG2zybfdeFQMrmPYCyJC8CShx9ug/s400/ash.jpg" width="278" height="400" data-original-width="450" data-original-height="648" /></a></div>This photo was taken 12 miles northeast of Helena, Montana. The white streak is a layer of ash from the explosive eruption of Mt. Mazama (Oregon) 7,700 years ago. Geologists can determine where the ash originated by comparing its chemical composition with the compositions of volcanoes found in the region. .<P>
The volume of ash produced by Mazama was forty-two times greater than the amount produced by St. Helens in 1980. Prevailing winds caused the ash to spread eastward. Initially the ash covered much of the ground in the Northwest. But in the months following the eruption, wind and runoff transported the ash to low places (lakes, valleys), where it was eventually buried beneath layers of sediment. Today it can be seen in places where it has been exposed in road-cuts, cut banks, archeological digs, etc. The sediment above the ash layer in the photo to the right was deposited in the centuries after the ash settled here, then the exposed when road construction cut into the slope.<P>
The Mazama ash layer has been found at many other places in the Northwest as well. In fact, Mazama ash serves as a good "key bed" for the region. Key beds help determine relative age - For example, several years ago archeologists came upon Mazama ash while excavating a Paleo-Indian campsite near Helmville, Montana. Mazama ash was exposed at the dig site ABOVE the evidence, indicating that the Indians used the site before the big eruption (at least 7,700 years ago). <P>
The Mazama eruption also emptied significant amounts of magma from the chamber beneath the volcano. As a result, after the eruption the remaining cone collapsed into the chamber, forming a huge crater known as a "caldera". Today, Crater Lake (Oregon) fills the caldera.<P>
For much more about Mazama Ash, <a href=http://iceagefloods.blogspot.com/2014/12/mazama-ash-from-crater-lake-volcano.html><b>CLICK HERE</B></A><P>
Also, check out my Montana hiking blog at <a href=https://bigskywalker.com/><b>www.bigskywalker.com</b></a> - Lots of geology!Rod Bensonhttp://www.blogger.com/profile/07896836810905406697noreply@blogger.com0tag:blogger.com,1999:blog-5589900626143831959.post-52648326302631005462018-10-23T18:57:00.000-07:002018-10-23T18:57:53.072-07:00Understanding Natural Climate CyclesThe connection between Milankovitch Cycles and Ice Ages was established decades ago. However, climatologists have long wondered how such small changes in Earth's tilt and orbit could cause such big changes in climate. This video looks at a possible explanation. <P>
<iframe width="560" height="315" src="https://www.youtube.com/embed/ZpFQbSyvkbA" frameborder="0" allow="autoplay; encrypted-media" allowfullscreen></iframe>Rod Bensonhttp://www.blogger.com/profile/07896836810905406697noreply@blogger.com0tag:blogger.com,1999:blog-5589900626143831959.post-33864161521443473902018-10-13T09:42:00.002-07:002018-10-17T07:05:15.953-07:00Check out this Slick Crossword Puzzle-MakerI wanted to make a crossword puzzle to help my students review some terms that were included in our recent hydrology unit. I found this site: crosswordhobbyest.com - Although the puzzle did not include all of the terms that I entered*, I'm satisfied with the end product. To access the puzzle <a href=http://CrosswordHobbyist.com/539592><b>CLICK HERE</b></a>, or (to see a different look) click on the "start puzzling" link below.<P>
*Unfortunately the puzzle-maker was not able to include these words: watershed, septic system, recharge, aeration.<P>
<script type="text/javascript" src="https://CrosswordHobbyist.com/embedjs.php?puzzle_id=539592"></script><P>
Rod Bensonhttp://www.blogger.com/profile/07896836810905406697noreply@blogger.com0tag:blogger.com,1999:blog-5589900626143831959.post-18145314268561364442018-09-19T20:55:00.001-07:002019-03-01T19:53:56.604-08:00Marble formed by Contact Metamorphism<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjkXHRhzE9CB_9c-uY0hgZozhVnVxnzHeEUsbBPfWaINr7Eko2P1unhWPo3wmPwWdTnzVzvkBnDyFmzd5OEAXo7H7FgUKS6GInF1e6f4qb1oP95j_63erDG9dFNBisSJePMCTvBIgn0kqw/s1600/EsciGuy.jpg" imageanchor="1" ><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjkXHRhzE9CB_9c-uY0hgZozhVnVxnzHeEUsbBPfWaINr7Eko2P1unhWPo3wmPwWdTnzVzvkBnDyFmzd5OEAXo7H7FgUKS6GInF1e6f4qb1oP95j_63erDG9dFNBisSJePMCTvBIgn0kqw/s640/EsciGuy.jpg" width="704" height="396" data-original-width="1600" data-original-height="900" /></a><P><b>The Elkhorn Mountain Volcanics.</b><br>The Elkhorn Mountains south of Helena, Montana are the remnants of volcanoes that were active in this area 74 to 81 million years ago. During that period, a tectonic plate was subducting beneath western North America, allowing magma to rise to the surface. As a result, the Elkhorns are made up primarily of extrusive igneous rocks, but are related to plutonic rocks of the nearby Boulder Batholith. The volcanic rocks that make up the Elkhorns (lots of andesite) formed when lava poured onto the surface and cooled, whereas the plutonic rocks (granite, etc.) of the batholith formed as magma beneath the volcanoes cooled underground.<P>
<b>Contact Metamorphism.</b><br>Despite the volcanic origin of the Elkhorns, the outcropping shown in the photo is made of marble - a metamorphic rock formed as limestone was changed by heat and/or pressure. Sometime during the late Cretaceous, magma melted its way into the area, coming close enough its heat to change the limestone into marble - a process known as “contact metamorphism”. Evidence for this is the presence of granite (formed as that magma cooled), located not far below the marble.<P>
<b>Ancient hot springs?</b><br>Limestone is usually formed by sediment deposited in a shallow tropical sea, so how did limestone form in a center of volcanic activity? One possibility is that hot springs existed here when the area was volcanically active. An unusual variety of limestone called "travertine" can form on the surface around hot springs by the rapid precipitation of calcium carbonate. This is what is happening today at Mammoth Hot Springs in Yellowstone Park where thick terraces of travertine continue to form as hot water comes to the surface.<P>
<b>Finishing touches.</b><br>In the millions of years that followed, the igneous rocks and marble were deformed (folded, faulted) by tectonic forces that built the Rocky Mountains (80 to 55 mya). As the formations were pushed up, they were also shaped by erosion, including glaciation. In fact, the marble in the photo marks the top of a cirque formed by a glacier that once (or multiple times) flowed from Elkhorn Peak toward the present-day location of the town of Elkhorn. More significant cirques lie on the northeast sides of Elkhorn Peak and Crow Peak - the two high points in the range. (<a href= https://caltopo.com/map.html#ll=46.30221,-111.91399&z=14&b=t&o=f16a%2Cr&n=1,0.25><B>Map</b></a>)
<P>
<P>
<b>Term to define:</b> contact metamorphism<P>
To access a blog a photo tour of the hike to the summits of Elkhorn Peak and Crow Peak, go to <a href=https://bigskywalker.com/2018/09/18/peak-bagging-in-the-elkhorns-with-the-hhs-outdoors-club/><b>www.BigSkyWalker.com</b></a>.<P>
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiazvmzl9ksVjFJutBXbOIBQ_opJ9xivqKdg60PoBrNGGePf7l7VXThwhQzLmUQXFyzFkjLTqdDItRb_Yz4Lv8HZAWU3HluEaFTUkaNWGYu49v-bTBsH7771bsV-q4jAUNa7ptLZOP2vXo/s1600/marble.jpg" imageanchor="1" ><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiazvmzl9ksVjFJutBXbOIBQ_opJ9xivqKdg60PoBrNGGePf7l7VXThwhQzLmUQXFyzFkjLTqdDItRb_Yz4Lv8HZAWU3HluEaFTUkaNWGYu49v-bTBsH7771bsV-q4jAUNa7ptLZOP2vXo/s640/marble.jpg" width="640" height="154" data-original-width="1600" data-original-height="385" /></a>Rod Bensonhttp://www.blogger.com/profile/07896836810905406697noreply@blogger.com3tag:blogger.com,1999:blog-5589900626143831959.post-57125415544928886762018-07-26T15:26:00.001-07:002019-03-01T19:55:00.942-08:00Mountains of Conglomerate in Southern Montana<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj1suAKD2b-l1cDZWjnyKGN3UiNaoKd63NQIfwgHZAcvfOzE0YdMgZM3zipb0hxh2khJ5AKl5L1UniyWwNIo5slICcDouc5EZX7UWwHdWUyX86Co-F03_d9RF2RNhkzR2lpLusTmZvZamk/s1600/EPODhelmet.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj1suAKD2b-l1cDZWjnyKGN3UiNaoKd63NQIfwgHZAcvfOzE0YdMgZM3zipb0hxh2khJ5AKl5L1UniyWwNIo5slICcDouc5EZX7UWwHdWUyX86Co-F03_d9RF2RNhkzR2lpLusTmZvZamk/s640/EPODhelmet.jpg" width="640" height="360" data-original-width="1600" data-original-height="900" /></a></div><P>
This unusual peak, called “The Helmet”, is located in the Madison Range of southern Montana, 22 miles northwest of Yellowstone Park. The photo was taken as friends and I descended from a neighboring peak called Sphinx Mountain. The Helmet is so-named because it resembles the comb on a Spartan’s helmet, and Sphinx Mountain was so-named because it looks like Egypt’s famous Sphinx when viewed from the north. Besides their unusual shapes, the two peaks share another strange feature - Both are made of a fairly uncommon rock called “conglomerate”.<P>
Conglomerate is a sedimentary rock (sandstone, shale, and limestone are others). With conglomerate, the sediment that became rock was gravel. It is unusual to find a whole mountain made of layer upon layer of conglomerate, but that is the case with Sphinx Mountain and The Helmet. Both mountains are composed entirely of thick layers of a “limestone conglomerate” - pebbles, cobbles, and boulders of limestone embedded in a reddish sandstone matrix. All total, the beds of conglomerate are over 2,000 feet thick.<P>
It is believed that the gravel was deposited here during the Eocene period (56-34 mya), when the area was a basin. The basin, which was probably much more extensive during the Eocene, presently occupies an area of only 2 square miles - and it’s not a basin any more. Over millions of years the layers of gravel became stone, and then were pushed up as the Rockies formed. Now Sphinx Mountain (10,876 ft.), one of Montana’s most iconic peaks, stands as a remnant of this gravelly basin. The Sphinx conglomerate is found only on Sphinx Mountain and The Helmet.<P>
<P>
<b>Term to define:</b> basin<P>
To see more photos of Sphinx Mountain, The Helmet, and the Sphinx conglomerate, go to <a href=https://bigskywalker.com/2018/07/25/sphinx-mountain-in-the-madison-range-southwest-of-bozeman/><B>Bigskywalker.com</b></a>.<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgL5wQqT4kTveSGTr8ORYPkM5ly60l9eba4ZwUOtnz-d1Q6R-berDrSs_dpx3-qinpSjJeBqSgzOaq48Oe9SRYGi8kiDKuUQmOK2iBOxqO_33gHvGHNYuddawakGo3Az8nOdbRrHs_oJRg/s1600/EPOD%2523.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgL5wQqT4kTveSGTr8ORYPkM5ly60l9eba4ZwUOtnz-d1Q6R-berDrSs_dpx3-qinpSjJeBqSgzOaq48Oe9SRYGi8kiDKuUQmOK2iBOxqO_33gHvGHNYuddawakGo3Az8nOdbRrHs_oJRg/s400/EPOD%2523.jpg" width="400" height="225" data-original-width="1594" data-original-height="897" /></a></div>
Rod Bensonhttp://www.blogger.com/profile/07896836810905406697noreply@blogger.com1tag:blogger.com,1999:blog-5589900626143831959.post-7492142170188052512018-02-08T19:10:00.000-08:002018-02-09T07:39:45.848-08:00Strange Flow of Rocks is Remnant of Rock Glacier<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgNNB-bA8M5XJXXgdycQkWAulcFyyvnD4iFFZd_Jxcfp2aBrPrzRBpW9iid3wQw8MeevPHvxm_ed-VlAAZuG-37gaign6ypp8tZlUSgkBJmlOjYrGXP83QWBpGtToU2zDDK9ECBs6AG-fY/s1600/epodPowell.jpg" imageanchor="1" ><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgNNB-bA8M5XJXXgdycQkWAulcFyyvnD4iFFZd_Jxcfp2aBrPrzRBpW9iid3wQw8MeevPHvxm_ed-VlAAZuG-37gaign6ypp8tZlUSgkBJmlOjYrGXP83QWBpGtToU2zDDK9ECBs6AG-fY/s640/epodPowell.jpg" width="640" height="480" data-original-width="1600" data-original-height="1200" /></a><P>This photo of Mt. Powell (10,168 ft.) in western Montana shows an impressive cirque, shaped by a glacier that once flowed from Powell’s northeast slope, down toward the valley of the Clark Fork River. According to geology maps, the strange flow-shaped mass of rocks near the bottom of the cirque was left by a “rock glacier”. Apparently during the final decades of Mt. Powell’s glacier, there were more rocks than ice in the mix. Eventually even the ice between the rocks melted away, and the rocks were left without a “ride”. From the summit, the deposit looks like a fluid blob of rocks, but without the matrix of ice the rocks are no longer flowing. <P>
<a href=https://bigskywalker.com/2018/02/07/mt-powell-on-the-rim-of-the-crater/><B>More about this hike - www.bigskywalker.com</b></a><P>
<a href=https://geology.com/articles/rock-glacier/><B>More about rock glaciers from Geology.com.</b></a> <br>
Rod Bensonhttp://www.blogger.com/profile/07896836810905406697noreply@blogger.com0