Confluence of the Green and Colorado Rivers

Early in Thanksgiving week we were able to visit an iconic location of the American West, the confluence of the Green (left) and Colorado (right) Rivers. There has been so much written about these rivers and so much western history has happened between the two rivers that a visit here is really mandatory for any devotee of the area.

You can clearly see the Green River with a large dose of suspended solids coming into the main stem of the Colorado looking just like a lateral moraine between two converging alpine glaciers. It is interesting to watch the dividing line between the two rivers slowly dissipate as you travel down stream. Any trace of this division will be obliterated in about four miles when the rivers passes through the upper most rapid in Cataract Canyon, Brown Betty.

Last year, I had the opportunity to fly over the confluence and experience the "google earth" view. You can see the silty Green River water staying remarkably separate from the Colorado for quite a ways further than this year's experience. The biggest reason was last year's discharge was approximately 800 cfs and this year it was flowing at over 2400 cfs.

Decorative rock and the Cutler formation

My next door neighbor, a retired local rancher invited me over to check out his new boulder. His ranch is in the valley below a great outcrop of Cutler and he decided that this conglomerate needed to be in his retirement from yard. His real reason for inviting me over was to give a quick historical geology lesson about the origins of his boulder.

The Cutler, at least here in Western Colorado is a rough conglomerate filled with the practically unsorted material that eroded off of the Ancestral Rockies...or at least here the Ancestral Uncompahgre Plateau. If my photo taking skills were better, you would be able to see largish cobbles (I did remember to add a nickle for scale) of all sorts showing the type of rocks that made the highlands of the Pennsylvanian. We discussed how you could break off a larger cobble and hold in your hand a chunk of rock from an ancient mountain range. He was impressed that he took the boulder from the location that gives its name to the formation. Cutler Creek.

Coupled with the Fountain formation, Minturn formation and the Maroon formation (all contemporaries, all red beds and all conglomerates) we see the outlines of the Ancestral Rockies during the Pennsylvania and Permian periods. This has been a great exercise with my students in trying to determine the extent of this ancient mountain range from data easily dug up today. They can visualize the high energy environment that mimics what we see in the mountains today creating these alluvial fans of conglomerate.

Teaching Science to Kids

Way back in my undergraduate days I had the chance to either do the industry thing (in geology that often means oil fields) or go into education. I chose geology education, especially in the K-12 arena. I guess this explains why I didn't get the memo about the demise of the Tertiary...but I digress.

There have been lots of great and not so great programs that have crossed into my classroom. I was a charter member in the Colorado River watch project where we studied the geology-chemistry-physics of rivers to determine overall stream health (biology). The image here is a group of teachers learning how to calculate discharge.

I spent a week at the Colorado School of Mines campus learning how to operate state of the art seismographs to be placed at local schools (that one was shot down by a building principal).

I could go on about the GLOBE program, project wild, wet, damp and all of the others. All very good programs that have stood the test of time. I have just been introduced to another program. This one aimed at middle school kids. (Research tells us that many kids choose the scientist track as 8th graders. )

The JASON project has been around for awhile, but its newest iteration as a subsidiary of National Geographic is one of the best mechanisms to get kids excited about science that I have seen for awhile. The idea is to use new cutting edge ideas AND their researchers to grab the kids. Yes, they start by focusing on the sexy stuff, (flying into hurricanes and swimming with sharks) but they end by hitting all of the key concepts in that discipline as well as doing some good middle school science and in an affordable way. It's not just about the activities they do with the kids but the concepts are backed up by the traditional print text books (think National Geographic for kids)and an impressive array of resources on their web site. Yes, finally a public school curriculum that uses the power of the Internet!

Lets continue to support teachers getting kids excited about science.

wild animals in the field

Things have been really busy this past month...but I couldn't help but want to post my little part of the animal meme.

Its funny with all the time I spend in my outdoor lab, there are few animals that I have seen and even fewer that have been out at the same time the camera was out.

The turtles on the C&O canal were fun to watch. I live in the arid west and am not used to such aquatic species.




I have already posted this picture when we saw the baby lambs learning rock climbing skills near the Gunnison River.











Of course there is lots of evidence of animals in the distant past.









and the high altitude mountain goats.

No Child Left Inside: 4th Graders in the Red Mountain Mining District

Last week I took a group of 4th Graders from a nearby elementary school to the old ghost town (I guess there aren't any new ones) of Ironton Colorado. This area is smack in the middle of the Red Mountain Mining District and has quite a few nearby mines to examine. Here we are standing on the tailings from the Larson Brothers mine. The mining district is pretty much right on the rim of the Silverton caldera, with the ore deposits all being associated with breccia pipes and the ring fault system at the rim of the caldera. Walking around the district you can see the remnants of the breccia pipes with small mines (and the occasional large one) at each base.

The kids were quite interested in the color of the water coming out of the mine and even though the chemistry was a bit over their heads, they got the idea that the pyrite oxidised into a strong acid. Then they all jumped over the stream so that the acid water wouldn't dissolve their shoes.

From here, we walked up valley into the town itself and then visited the renovated Colorado Boy headframe. The Colorado Historical Society has done an awesome job restoring the structure which I have shown to my college and high school classes on our field trips here. There is not much written about what was mined here beyond the usual, copper, silver and galena ores. It is also a great place to take a rest during a mid winter ski. This picture nor the next was of course not taken last week

Above the Colorado Boy is the remnants of an old wooden flume that transported a tailings slurry to the massive tailings pile in the valley bottom. The image here is the old suspension structure carrying the pipline across Corkscrew Gulch. Legend around here suggests that when this was made, it was the 2nd largest suspension bridge in Colorado. They engineered the pipeline so that it bowed upwards when there was no load and then during slurry operations it would assume the correct downward slant. Please don't cross the bridge now!

geologic time and the budget- An analogy of sorts

Well,

I was thinking about asking the Department of the Treasury for some help this semester in explaining exactly what 4.5 billion years looks like. They seem to have no problems with really large numbers. Here is a link to a story about the national debt clock being out of room.

Perhaps scientific notation will help? How many significant digits do you want?

Black Rocks

Last weekend was spent on a stretch of the Colorado River through Ruby and Horse thief Canyons. It was an awesome early fall day with warm daytime temperatures and the leaves just starting to turn.

Here, our flotilla is approaching the Black Rocks Monocline. Black rocks is the local name for...well, an outcrop of black rocks where this stretch of river sees its only rapid. I am not sure but it seems as if the Laramide left us more than our fair share of monoclines on the Colorado Plateau. My field work is very limited, but we seem to have a bunch. Anyway. The monocline shows a great bend in the Wingate-Kayenta-Chinle combination, much different from the usual flat lying cliffs we are used to seeing. Around the river bend will be the Black Rocks. These pre-Cambrian rocks are much harder than the Mesozoic sediments found everywhere else. The river channel in this section is much narrower, but deeper and the whole flow must squeeze through the channel creating a faster current, with some great hydraulics. I have seen whirlpools appear out of now where and just slap a canoe over, capsizing the boat and throwing dinner into the water, not to mention the two paddlers.

These rocks have been dated to 1.7 billion years old and it looks like a migmatic pegmatite with a few quartz veins shooting through (did I think of taking a close up...no) We had even camped one canyon up river with a great outcrop of the same material. Oh well, sitting right on top of this early Proterozoic black rock is the Mesozoic Chinle formation which clocks in at about 200 million years old. This trip was for fun, but every early summer I take a few geology-hungry K-12 teachers down this stretch and they love being able to stand on 1.5 billion years of missing Earth history. wow!