Seeing the Rock Cycle in the Ozarks

September 25, 2016

On this year’s trip to the Current River with the Middle School we were able to see outcrops of the three major types of rocks: igneous, metamorphic, and sedimentary.

Igneous Rocks

Beautiful, pink granite at Elephant Rocks State Park.

Beautiful, pink granite at Elephant Rocks State Park.

We stopped by Elephant Rocks State Park on the way down to the river to check out the gorgeous pink granite that makes up the large boulders. The coarse grains of quartz (translucent) interbedded with the pink orthoclase crystals make for an excellent example of a slow-cooling igneous rock.

Metamorphic Rocks

The Prairie Creek waterfall pool.

The Prairie Creek waterfall pool.

On the second day out on the canoes we clambered up the rocks in the Prairie Creek valley to see jump into the small waterfall pool. The rocks turned out to look a lot like the granite of Elephant Rocks if the large crystals had been heated up and deformed plastically. This initial stage of the transformation allowed me to talk about metamorphic rocks althought we’ll see some much more typical samples when we get back to the classroom.

Prairie Creek rocks.

Prairie Creek rocks.

Sedimentary Rocks

Limestone bluffs along the Current River.

Limestone bluffs along the Current River.

We visited a limestone cave on the third day, although we’ve been canoeing through a lot of limestone for on the previous two days. This allowed us to talk about sedimentary rocks: their formation in the ocean and then uplift via tectonic collisions.

The Rock Cycle

Diagram of a convergent tectonic margin used to illustrate the rock cycle.

Diagram of a convergent tectonic margin used to illustrate the rock cycle.

Back at camp, we summarized what we saw with a discussion of the rock cycle, using a convergent plate margin as an example. Note: sleeping mats turned out to be excellent models for converging tectonic plates.

Note to self: It might make sense to add extra time at the beginning and end of the trip to do some more geology stops. Johnson Shut-Inns State Park is between Elephant Rocks and Eminence, and we saw a lot of interesting sedimentary outcrops on the way back to school as we headed up to Rolla.

Citing this post: Urbano, L., 2016. Seeing the Rock Cycle in the Ozarks, Retrieved April 23rd, 2017, from Montessori Muddle: http://MontessoriMuddle.org/ .
Attribution (Curator's Code ): Via: Montessori Muddle; Hat tip: Montessori Muddle.

Elephant Rocks

October 13, 2014

Students explore the massive, spheroidally weathered boulders at Elephant Rocks State Park.

Students explore the massive, spheroidally weathered boulders at Elephant Rocks State Park.

We stopped at the Elephant Rocks State Park our way down to Eminence MO for our middle school immersion trip. The rocks are the remnants of a granitic pluton (a big blob of molten rock) that cooled underground about 1.5 billion years ago. As the strata above the cooled rock were eroded away the pressure release created vertical and horizontal cracks (joints). Water seeped into those joints, weathered the minerals (dissolution and hydrolysis mainly), and eroded the sediments produced, to create the rounded shapes the students had a hard time leaving behind.

This was a great stop, that I think we’ll need to keep on the agenda for the next the next trip. I did consider stopping at the Johnson’s Shut-Ins Park as well, but we were late enough getting to Eminence as it was. Perhaps next time.

Exploring the spaces between the rocks.

Exploring the spaces between the rocks.

Citing this post: Urbano, L., 2014. Elephant Rocks, Retrieved April 23rd, 2017, from Montessori Muddle: http://MontessoriMuddle.org/ .
Attribution (Curator's Code ): Via: Montessori Muddle; Hat tip: Montessori Muddle.

Plate Tectonics on the Eminence Immersion

October 13, 2014

tectonics-IMG_20141007_093449722

The picture of a convergent tectonic boundary pulls together our immersion trip to Eminence, and the geology we’ve been studying this quarter. We saw granite boulders at Elephant Rocks; climbed on a rhyolite outcrop near the Current River; spelunked through limestone/dolomitic caverns; and looked at sandstone and shale outcrops on the road to and from school.

An oceanic-oceanic subduction zone. The subducting plate melts producing volatile magma.

The subducting plate melts producing volatile magma.

Citing this post: Urbano, L., 2014. Plate Tectonics on the Eminence Immersion , Retrieved April 23rd, 2017, from Montessori Muddle: http://MontessoriMuddle.org/ .
Attribution (Curator's Code ): Via: Montessori Muddle; Hat tip: Montessori Muddle.

Back to Heifer

September 23, 2013

Our initial briefing on getting to the Heifer Ranch.

Our initial briefing on getting to the Heifer Ranch.

We’re off to Heifer International again with a new crop of middle-schoolers. This time Ms. Vranas is the other chaperone.

With stopping for lunch, stopping for gas, and stopping by a grocery to pick up supplies, the trip out lasted over 8 hours, but we made it out with everyone in good humor. The kids played Head’s Up Seven Up, and their own stashes of snack food.

I use these trips to introduce geology, specifically the dynamics of mountain-building and erosion using the Ozarks as an example. So every time we passed an outcrop (of which there were quite a number) I pointed it out and one of the students would invariably shout out “limestone” (and sometimes it actually was). I’ll actually try to take pictures of the outcrops on the way back when I’m not driving.

After dinners, I usually have the students spend an hour on reflection and discussion. The group gets split in two. While one half writes I discuss something we’ve seen with the other half.

I was planning to talk about the sequence of outcrops tonight, however, the discussion broke in a slightly different direction.

Just after crossing the Arkansas river, I’d asked the students why the land was so flat. It was because we were on the floodplain, but few of them had picked it up. In fact, most of them had not even noticed we’d crossed a fairly large river on a big concrete bridge not 30 seconds before.

So we started talking about why the flood plain is flat, then got on to the erosion of mountains and the deposition of the eroded material on the flood plains and river deltas. The key factor in erosion and deposition is the energy of the stream, which is a function of the slope. This in turn lead us to to talk about the Nile River – as an example -, which lead to the Great Pyramids, and how the fertility of floodplains lead to agriculture and civilization in Egypt, Mesopotamia, Cahokia, and along the Indus. I ended by pointing that most major cities are located on rivers because of their agricultural fertility, and perhaps more importantly today, the utility for transportation.

A) A landscape profile showing areas of erosion and deposition, including a delta. B) An erosional and depositional (lower) valley. C. Map view of a delta (like the Mississippi River delta). D. An older mountain range that's been eroded.

A) A landscape profile showing areas of erosion and deposition, including a delta. B) An erosional and depositional (lower) valley. C. Map view of a delta (like the Mississippi River delta). D. An older mountain range that’s been eroded.

When the discussions and writing groups broke up, a few started to play Bananagrams, while the rest got a little rowdy. So I pulled them all in again and we talked a little about adolescent development, self-control, and the development of the frontal lobe, as I read them the riot act on proper behavior. It turned into a pretty neat discussion, because they ended up interrogating me about the way I behave toward them: why I always pause a moment before answering even their simplest questions; why I laughed two weeks ago when one of them told me that I was their, “least favorite teacher”; things like that.

Citing this post: Urbano, L., 2013. Back to Heifer, Retrieved April 23rd, 2017, from Montessori Muddle: http://MontessoriMuddle.org/ .
Attribution (Curator's Code ): Via: Montessori Muddle; Hat tip: Montessori Muddle.

Understanding the Extinction of the Dinosaurs (and the Survival of Mammals)

July 28, 2013

This neat paper (Robertson et al., 2013) in the Journal of Geophysical Research makes an interesting attempt to explain the pattern of extinctions that occurred at the end of the Cretaceous: why most of the dinosaurs died out, and why ocean organisms were more severely affected than freshwater organisms by the long winter after the asteroid impact.

The flow chart explains:

Diagram of contrasts between freshwater and marine environments for factors potentially causing extinction in aquatic environments after the Chicxulub impact. (Image and caption from Robertson et al., 2013).

Diagram of contrasts between freshwater and marine environments for factors potentially causing extinction in aquatic environments after the Chicxulub impact. (Image and caption from Robertson et al., 2013).

They also include an interesting figure showing how long an organism might survive based on how large it is, which I may be able to use in pre-Calculus when we’re discussing log scales and linearizing equations.

Allometric relationship between body size and time to death by starvation for multicellular poikilotherms in the absence of food (red, drawn from the equation of Peters [1983, p. 42]). Names of various types of organisms are shown as an indication of body size. Image and caption from Robertson et al., 2013.

Allometric relationship between body size and time to death by starvation for multicellular poikilotherms in the absence of food (red, drawn from the equation of Peters [1983, p. 42]). Names of various types of organisms are shown as an indication of body size. (Image and caption from Robertson et al., 2013.)

The article is written well enough that an interested high school biology student should be able to decipher (and present) it.

Citing this post: Urbano, L., 2013. Understanding the Extinction of the Dinosaurs (and the Survival of Mammals), Retrieved April 23rd, 2017, from Montessori Muddle: http://MontessoriMuddle.org/ .
Attribution (Curator's Code ): Via: Montessori Muddle; Hat tip: Montessori Muddle.

Johnson’s Shut Ins

July 20, 2013

Exploring the natural water works at the Johnson's Shut Ins.

Exploring the natural water works at the Johnson’s Shut Ins.

First off, the Shut Ins are narrower constrictions in the river valley formed when stream flows into an area of harder rock. The hard rock, in this case an old (1.5 billion year old) rhyolite flow, is relatively resistant to erosion, especially the side-to-side erosion that flattens out little flood plains as small rivers meander through the foothills of old mountains like the Ozarks. So the stream only erodes downward through the hard rocks creating a narrow gorge. As they say here: the river’s “Shut In”.

When I told people that I wanted to do a few camping trips this summer, the number one recommendation was the Shut Ins. And I can see why. I took my boys and they had an awesome time.

“It’s like the City Museum. Only real.”
— Overheard at Johnson’s Shut Ins

The Shut Ins are a maze of narrow channels, the old igneous rocks carved smooth by the water and its gravelly bed load over millions of years. A great place for kids to traipse through and explore. I bit like a water-park version of the City Museum in St. Louis.

Rushing water in a shallow channel leads to a deeper pool.

Rushing water in a shallow channel leads to a deeper pool.

Looking down from the cliffs above the Shut Ins, the sets of linear joints in the rocks are quite clear.

Looking down from the cliffs above the Shut Ins, the sets of linear joints in the rocks are quite clear.

The pattern of the channels is largely determined by the jointing in the rocks, because the joints offer easier pathways for water and erosion. There are at least two obvious sets of joints in the rocks, but I would not be surprised if they overlay other patterns given how old the rocks are. As it is, however, the erosion through the joints creates lots of neat little chutes.

Looking along a narrow eroded joint.

Looking along a narrow eroded joint.

Since the Shut Ins are only a couple hours away from St. Louis, they’re a pretty popular tourist attraction.

Population density is high.

Population density is high.

There’s a lot of science that can be done here, however, that would make this a good location for an immersion trip, especially since Elephant Hills State Park (with wonderful spheroidal weathering) is close by. The camping facilities at the Shut Ins State Park are new and quite nice, having been completely rebuilt with some of the $100 million in settlement money from the Ameren power company after the park was flooded by their Taum Sauk reservoir breach in 2005.

The path of the wave from the Taum Sauk reservoir breach created a debris field with huge boulders, and demolished the original Johnson's Shut Ins campground. The Shut Ins themselves are downstream to the right.

The path of the wave from the Taum Sauk reservoir breach created a debris field with huge boulders, and demolished the original Johnson’s Shut Ins campground. The Shut Ins themselves are downstream to the right.

It’s certainly worth the visit.

As the stream exits the Shut Ins it has dredged some excellent swimming pools.

As the stream exits the Shut Ins it has dredged some excellent swimming pools.

Citing this post: Urbano, L., 2013. Johnson's Shut Ins, Retrieved April 23rd, 2017, from Montessori Muddle: http://MontessoriMuddle.org/ .
Attribution (Curator's Code ): Via: Montessori Muddle; Hat tip: Montessori Muddle.

Wandering Through the Creek

March 2, 2013

Inspecting the creek.

The rapid, snow-melt driven, flow in the creek has receded a little, but it managed to clear out most of the dead leaves that have carpeted the stream bed since the fall. Now that the rocky bottom is exposed, hopefully, we’ll be able to see some more of the benthic fauna that’s been invisible for the last few months.

Washing out the dead leaves has exposed the rocks and rapids.

Citing this post: Urbano, L., 2013. Wandering Through the Creek, Retrieved April 23rd, 2017, from Montessori Muddle: http://MontessoriMuddle.org/ .
Attribution (Curator's Code ): Via: Montessori Muddle; Hat tip: Montessori Muddle.

Assessment with the Toilet Paper Timeline of Earth History

December 17, 2012

With a larger class, and quite a bit of space in the gym, I had more flexibility working on the toilet paper timeline compared to the last time.

Labeling the timeline in the gym.

I built in a friendly race to see which group could find a set of events first, and allowed me to highlight nine different, important, series of events along the timeline.

The adapted spreadsheet, racing sequences, and a short summative quiz are on this Toilet Paper Timeline spreadsheet.

I broke the class up into 4 groups of 4, and each group created their own timeline based on a handout.

Groups of students lay out their toilet paper timelines. Post-it notes were used to label the events.

Then, I gave each group a slip of paper with four events on it (one event per student), and they had to race to see which group would be first to get one person to each event on the list. Once each group got themselves sorted out, I took a few minutes to talk about why the events were important and how they were related.

Table 1: The series of events.

1) We’ll be talking about plate tectonics soon, so it’s good for them to start thinking about the timing of the formation and breakup of the supercontinents.
Event 1 Event 2 Event 3 Event 4
Formation of Rodinia (supercontinent) Breakup of Rodina Formation of Pangea Breakup of Pangea
2) This sequence emphasizes the fact that most free oxygen in the atmosphere comes from ocean plants (plankton especially), and that a lot of free atmospheric oxygen was needed to to form the ozone layer which protected the Earth’s surface from uv radiation, which made the land much more amenable to life. Also, trees came way after first plants and oxygen in the atmosphere.
Event 1 Event 2 Event 3 Event 4
First life (stromatolites) Oxygen buildup in atmosphere First land plants First Trees
3) Pointing out that flowering plants came after trees.
Event 1 Event 2 Event 3 Event 4
First life First land plants First trees First flowering plants
4) The Cambrian explosion, where multicellular life really took off, happened pretty late in timeline. Longer after the first life and first single-celled animals.
Event 1 Event 2 Event 3 Event 4
First life (stromatolites) First animals First multicelled organisms Rise of multicelled organisms
5) Moving down the phylogenetic tree from mammals to humans shows the relationship between the tree and evolution over time.
Event 1 Event 2 Event 3 Event 4
First mammals First Primates Homo erectus Homo sapiens
6) More tectonic events we’ll be talking about later.
Event 1 Event 2 Event 3 Event 4
Opening of the Atlantic Ocean Linking of North and South America India collides with Asia Opening of the Red Sea
7) Pointing out that life on land probably needed the magnetic field to protect from the solar wind (in addition to the ozone layer).
Event 1 Event 2 Event 3 Event 4
Formation of the Earth First life Formation of the Magnetic Field First land plants
8) Fish came before insect. This one seemed to stick in students’ minds.
Event 1 Event 2 Event 3 Event 4
First Fish First Insects First Dinosaurs First Mammals
9) Mammals came before the dinosaurs went extinct. This allowed a discussion of theories of why the dinosaurs went extinct (disease, asteroid, mammals eating the eggs, volcanic eruption in Deccan) and how paleontologists might test the theories.
Event 1 Event 2 Event 3 Event 4
First Dinosaurs First Mammals Dinosaur Extinction First Primates

The whole exercise took a few hours but I think it worked out very well. The following day I gave the quiz, posted in the excel file, where they had to figure out which of two events came first, and the students did a decent job at that as well.

Citing this post: Urbano, L., 2012. Assessment with the Toilet Paper Timeline of Earth History, Retrieved April 23rd, 2017, from Montessori Muddle: http://MontessoriMuddle.org/ .
Attribution (Curator's Code ): Via: Montessori Muddle; Hat tip: Montessori Muddle.

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