#121 - Nice (Gneiss) Basement Rock

First things first . . . This outcropping is located in a cirque called Beehive Basin about 35 miles SSW of Bozeman, Montana. An outcropping is a place where Earth's crust (bedrock) is exposed (not loose rock and not covered with soil, etc.) - usually a steep area. A cirque is a U-shaped mountain valleys carved by an alpine glacier. Point C on this aerial photo marks the location of the outcropping. Once the page opens, zoom out to see the entire valley, and beyond to get a sense of where this place is.

What's so nice about it? . . . The rock shown in the photo above is a type of metamorphic rock called gneiss (pronounced "nice"). Metamorphic rocks are formed when sedimentary or igneous rock is changed by heat and/or pressure (and in some cases, chemically active fluids). Gneiss can form from several different types of parent rocks, including granite, shale, or volcanic rocks, although most textbooks feature gneiss that was formed from granite. Other common metamorphic rocks include marble (used to be limestone), quartzite (used to be sandstone), and slate (used to be shale).

Not just for butterflies . . . Most metamorphism happens in one of two geologic settings. In one, heat from magma beneath the surface may "bake" (but not melt) rock, causing minerals in the rock to recrystallize or even form new minerals. In the other scenario pressure put on rock buried deep beneath the surface or rock near a colliding plate boundary can also cause metamorphism. The slow collision of tectonic plates squeezes large rock formations, causing them to become deformed and metamorphosed. The Rocky Mountains formed from this type of slow collision between 80 and 40 million years ago.

Old stuff in the basement . . . Gneiss makes up most of the lower portion of Earth's continental crust - very old material referred to as "basement rock". In most places basement rock is covered with younger sedimentary rocks. Drill down far enough anywhere on a continent - you will usually strike gneiss. In fact the rock that makes up the mountains in southern Montana, including the gneiss in the photo, are among the oldest in the state - formed during the Archean (Archeozoic) Eon over 2.5 billion years ago. Here, sections of crust were forced upward and many of the younger rock formations eroded away, exposing the basement rock. Today this gneiss makes up many of the mountains in the region, including the Beartooths, the Tobacco Roots, and a significant portion of the mountains in between.

Term: contact metamorphism, regional metamorphism (in your own words!)

#123 - Moraine of the Grinnell Glacier

This is as far as we go.

Grinnell Glacier Moraine . . . This photo, taken near Grinnell Glacier shows a ridge of rock material (till) known as an "end moraine". The moraine consists of rocks of various sizes (unsorted), ranging from silt to boulders - an obvious sign that they were deposited by a glacier. Rocks that were stuck to the bottom of the Grinnell Glacier (or had fallen onto it, etc.) were carried here by the glacier and then dropped as the ice melted at the terminus of the glacier. A significant moraine such as this indicates that the climate must have been stable for several decades, causing the terminus of the glacier to be stationary. If it had been advancing due to a cooling climate, or receding due to warming, the rock material would not have built up as it did here. The span of stable climate that allowed this moraine to form happened during the Little Ice Age, a cold period that lasted for centuries, ending in the mid-1800s. Since then the Grinnell Glacier has been receding due to the warming climate, causing the glacier to melt away from its moraine.

Not the first time the glaciers have melted away . . . Contrary to popular belief, the glaciers in Glacier Park are NOT "leftovers" from the last ice age, which ended roughly 10,000 years ago. There is little doubt that ice age glaciers WERE responsible for carving the majestic peaks and valleys of the park (horns, cirques, aretes, hanging valleys, etc.), however experts believe those glaciers completely melted away during a warm period 9,000 to 5,000 years ago (known as the altithermal or Holocene Climate Maximum). On the other hand, glaciers present in the park today formed during the Little Ice Age (not a true "ice age") - a centuries long cold period that ended about 150 years ago. According to evidence from moraines, tree rings, layers of volcanic ash, and radiometric dating, these "Little Ice Age" glaciers formed in cirques that were carved by glaciers during the last real ice age(s). The photo at the top of this page shows the end moraine that marks the farthest advance of the Grinnell Glacier during the Little Ice Age. The photo below shows that same moraine as viewed from Mt. Gould.

What if he had gone along? . . . Grinnell Glacier is named after George Bird Grinnell (1849-1938), an American anthropologist, historian, naturalist, and writer. Grinnell was born in New York, and graduated from Yale University with a B.A. in 1870 and a Ph.D. in 1880. As a graduate student, he accompanied Lieutenant Colonel George Armstrong Custer's 1874 Black Hills expedition as a naturalist. Fortunately he passed on a similar opportunity to accompany Custer on the 1876 expedition - All the participants on that trip died at the Battle of the Little Big Horn in June of 1876. Instead, Grinnell lived a long and influential life, which included playing a major role in establishing Glacier Park. After exploring the area in 1885, he was instrumental in getting it designated as a national park in 1910. Who knows? If Grinnell had gone with Custer, the area may have never become a national park.

Above: Lisa McKeon and Lindsey Bengtson photograph Grinnell Glacier from the summit of Mount Gould in August of 2009. Courtesy of the USGS

Term: glacial till

Leyden Jar Demo

Rub a piece of PVC pipe with fur as it slides past the nail (on top of clear plastic bottle). Electrons jump from the PVC to the nail and flow into the salty water. In the meantime, electrons in the foil (wrapped around bottle) are repelled, so they follow a ground wire to the faucet. The result is a positively charged foil and negatively charged salt-water - It's like a battery. After disconnecting the ground wire, all we need is a conductor to connect the foil and the nail. That's where the students come in.

Here's a link to the video I used to make the Leyen Jar. I did it a little differently - For one, I connected the foil to a water faucet usin a copper wire and tape. Also, I used a fur to charge the PVC.

Montana Outdoors (magazine) articles with questions

I've been working with Montana Fish, Wildlife & Parks to write evaluations (worksheets) that go along with articles from their Montana Outdoors Magazine. 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.
-Rod Benson

1. PDF Article about delisting grizzly bears: Ready for the Handoff

Worksheet with questions - Ready for the Handoff worksheet

Ready for the Handoff Kahoot Game

2. PDF Article about amphibians: It’s Not Easy Being Green

It's Not Easy Being Green Worksheet

3. PDF Article about raptor identification: 16 Raptors That Every Montanan Should (Kinda) Know

Raptors Worksheet

4. PDF Article about Aquatic Invasive Species

Aquatic Invasive Species Worksheet

5. PDF Article about managing wildlife - Micro and Macro

The worksheet for this article can be found on this web page.

6. PDF Articleabout the mental health benefits of spending time outdoors: A Healthy Dose of Nature

A Healthy Dose of Nature Worksheet

7. PDF Article about animal migration - Moving Right Along

Moving Right Along Worksheet

8. PDF Article about monitoring wildlife numbers: Tracking Wildlife’s Ups and Downs

The worksheet for this article can be found on this web page.

9. PDF Article about Chief Plenty Coups - Warrior to Warrior

Warrior to Warrior Worksheet

10. PDF Article about beavers - Leave it to Beavers

Leave it to Beavers Worksheet

For a complete list, including several that were designed before I came on board (multiple-choice format), go to the Montana Outdoors Literacy Program

#116 - Blowdown in SW Montana - aftermath of 2019 Microburst

Microburst?
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.

The sky is falling!
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.

Watch this 1-minute video of a microburst in Tucson, Arizona.

Mr. Tornado.
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.

Term: sublimation

For more about the area shown in the photo, go to Bigskywalker.com.

#106 - 1943 Smith Mine Disaster near Bearcreek, Montana - 75 men died

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 . . .

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.

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.

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.

Good-bye wives and daughters. We died an easy death. Love from both of us. Be good. Walter and Johnny.

The aftermath . . .

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)

Coal Use Then and Now . . .

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.

Coal Mining Then and Now . . .

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.

Term: dust explosion

For more about the disaster, including an article + a great 4-minute video, CLICK HERE.

Fun Density Demonstration

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.

Make the ice cube by adding several drops of blue food coloring to water before freezing it in a styrofoam cup.

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.

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.