As noted earlier, I had the good fortune to spend last week in Yosemite National Park, celebrating the wedding of my friends Jason and Lindsay, and in general poking around in one of the coolest places around. Below, a summary of the three-day trip:

Friday:
Lily and I flew to Modesto, California, and rented a car. It took about two hours to drive up to Evergreen Lodge, where we checked in and then headed out for a short hike in the Hetch Hetchy area. Hetch Hetchy was dubbed "Yosemite's sister valley" by John Muir in an attempt to keep it from being dammed. But the city of San Francisco had been destroyed in 1906 by earthquake-induced fire, and the call for a reliable water source was an important force in overpowering Muir's conservationist ideals. Ken Burns apparently explores this saga, the first instance of "development vs. conservation," in the second episode of his new National Parks series. (I saw the first episode, but haven't caught up on the rest of it yet.) The valley was dammed in the 1920's, creating the Hetch Hetchy Reservoir:


Here's the O'Shaughnessy Dam, named after the chief engineer of the project:


I didn't find it as spectacular as Yosemite, but it was sure a pretty place. Walking along the north side of the reservoir, I reaquanited myself with some fine Sierran granites and granodiorites. Here's a sweet little xenolith (or maybe an MME; how can you tell an MME from a mafic xenolith?):

Back to the Evergreen for the rehearsal dinner (Oktoberfest theme!) and then bed.

Saturday:
Up early, got some coffee, drove an hour to reach the Yosemite Valley. I liked how quiet things were compared to the throbbing pulse of summer. This view of El Capitan, for instance, is typically mobbed with tourists. This day, we had it to ourselves for five minutes or so, then shared it with one other car:


Time to stretch the legs! We decided to hike up to Vernal Falls. On our way up, the base of the falls was still in shadow, with low-angle morning sunlight dramatically illuminating the upper reaches of the falls:


Looking back down the valley we had climbed up... I like the dark shadow of the cliff merging with the dark shadows of the trees below:


But if we set the camera's F-stop a bit differently, we can see what's going on in all that shadow. There's the trail we climbed up, with fellow hikers for scale:


Up top, photographing the waterfall:


On our way back down, with more of the falls illuminated as the sun rises in the sky:


Looking north across the valley from where we parked our car, marvelling at the huge exfoliation joints there: rounding these exposed plutons into granite 'domes.'


... or Half Domes, as the case may be:


A view from further out, again with Half Dome the most striking landform:


Then, we headed back to clean up before the wedding. Great ceremony, amazing meal. Drinks, dancing, rhubarb jam, bluegrass, reminiscing with old friends and new. Ahhh.

Sunday:
Breakfast and coffee with the wedding party, then off to check out some big trees. We drove to the Tuolumne Grove of giant sequoias. It started snowing on the way there, but we didn't let that deter us. On the hike down from the parking area (where, by the way, they had closed the Tioga Road), we found this nice example of spheroidal weathering in an outcrop of granite:


But the real attraction was the enormous sequoia trees. Here's one:


And a dead one, with a car-sized hole cut through it:


I found these trees very impressive: they were just stunning in their grandeur and immense age. Snow continued to fall as we left. We had to get going to make our flight home. Somewhere on the way down the mountain, Garry Hayes and his wife passed us going up the mountain. Ships passing in the night -- sorry I missed you, Garry! We made a couple of roadside outcrop stops, then got back to Modesto and traded in the car for an airplane. Our "redeye" route back to DC took us through San Francisco and Los Angeles, and I ran into Thomas Friedman in the airport. Got back to BWI at 6am, and headed off to work...

Labels: california, glacial landforms, national parks, plants, travel, tv, water resources, xenoliths

An article in today's Post explains more.

Labels: coastal plain, maryland, plants

On my first day in Montana this summer, I borrowed Lily's Jeep and set off to look for petrified wood in the Tom Miner Basin, an offshoot of the Paradise Valley (which connects Livingston to Gardiner). Along the way, though, I stopped at Point of Rocks CKCK, and found some nice exposures of the lahar deposits of the Absaroka/Gallatin Volcanic Field. These Eocene-aged extrusions basically consist of a series of lava flows and volcaniclastics interlayered to a substantial thickness.

Here's a map of Point of Rocks:


Here's the view north from Point of Rocks:


Here's some images of the rocks exposed there: poorly-sorted, matrix-supported grey conglomerates that I interpret on the basis of the previous year's field notes to be lahar deposits:




I've got a big fat chunk of this stuff in the NOVA geology lab now -- thanks to Lily for giving that forty pounds of lahar a lift cross-country!

Eventually I made it into the Tom Miner Basin, an area of Forest Service land where there is some petrified wood exposed. There is an interpretive trail where people are specifically asked NOT to collect but of course people collect anyhow, so it's kind of lame, but there are some nice examples of petrified branches and what not, and some nice examples of reverse-graded-bedding in the lahar deposits.

Map of the area where the road ends (at a campsite) and the trail begins:


Reverse graded bedding:


You can climb up above the trail to some exposures of the volcanics which are harder to get to and therefore not picked-over, and with a permit you can collect a fist-sized chunk per person per year.

Here's a couple examples of petrified wood that I saw:




More volcaniclastics, this time showing normal graded bedding (coarse at the bottom, fine at the top):


And on the way out, I saw a nice example of a couple of rugose corals cross-sectioned in a boulder of presumably-Mississippian-aged Madison Group limestone:



It was a nice first day in Montana! More photos to come...

Labels: fossils, igneous, montana, plants, volcano

Bill Parker put up an interesting piece last night on the Chinleana blog about John Muir, the conservationist icon, studying fossils in Arizona's petrified forest (silicified trees in the Chinle Formation badlands). Great historical photos -- Check it out!

Labels: arizona, blogs, environmental, fossils, plants

There's an article on the Burgess Shale and another on inventorying all the plants on Plummers Island (home of the Plummers Island Thrust Fault, between DC and the Billy Goat Trail).

Labels: cambrian, dc, faults, fossils, plants

Yesterday, I lead a NOVA field studies trip to the Billy Goat Trail, and we were pleased to see that the recent rains had plumped up the big patch of Opuntia (beavertail) cactus near the boulder of Seneca Sandstone. These are native cacti which grow on poor soils in the area. These soils are poor because periodically the Bear Island strath (bedrock terrace), where the Billy Goat Trail is located, is scoured by the Potomac River's floods. These cacti are growing essentially in pine and juniper needles on top of bare rock (metagraywacke). What a beautiful sight!

Labels: maryland, piedmont, plants

These days, I'm busy getting things organized for my upcoming Regional Field Geology of the Northern Rockies class -- held next month in Montana and Wyoming. I'm taking the students to two new places that I've never been before, and so a lot of my prep time is learning more about those sites. One is Specimen Ridge in Yellowstone, where there are some petrified trees.

In researching Specimen Ridge, I came across the photos of thorton_3041, who posted an album of images online at Webshots. Look at this beautiful detail!



You can see the tree's rings in gorgeous detail, as well as the silica which filled in a rip (a dessication crack perhaps) in amorphous white, unconstrained by cell walls. My favorite is that little chunk of wood at the bottom, rotating into the void space like a xenolith stoping into a pluton. Check out Thorton's full album! I can't wait to see these trees myself this summer!

Labels: fossils, plants, wyoming, yellowstone

A shot from DC's Tidal Basin this weekend:

Labels: birdies, dc, plants

GSW Spring Field Trip: Sunday, May 17, 2009

The Potomac Gorge: An Extraordinary Meeting Place of Geological and Biological Diversity

Led by: Tony Fleming, Natural Areas Geologist, and Gary Fleming, Vegetation Ecologist, Virginia Department of Conservation and Recreation

The Potomac Gorge between Great Falls and Georgetown is recognized as one of the most biologically diverse sites in the eastern United States, with an unusually large concentration of rare flora, fauna, and natural communities. For more than a century, the gorge has also enjoyed an iconic reputation as the region's premier geological area, both for its exceptional exposures of Piedmont bedrock and the complex tectonic history they reveal, and for the natural fluvial cycle of flood disturbance that still operates on the Potomac, the only Fall Zone river of its size whose flow is not altered by dams. Geology and ecology converge on this field trip, as we visit two sites where geologic processes exert a powerful influence on the distribution of unusual natural communities. At Turkey Run Park, we will hike past steep boulderfield communities and regionally rare sugar maple/mixed mesophytic forests more typical of New England, here growing on soils weathered from basic intrusive rocks in a cool microclimate created by processes driven by Pleistocene glaciation and the ongoing southward migration of the Potomac Valley. Chain Bridge Flats, by contrast, is a unique flood-scoured bedrock terrace hundreds of hectares in size that displays a complete ecotone of communities adapted to progressive changes in the form and intensity of natural flood disturbance as one approaches the river. Among these are disjunct, prairie grasslands containing calcium-loving plants more typical of the Midwest and Great Lakes. This site also is the largest and cleanest exposure anywhere in the Piedmont of the Sykesville Formation, the enigmatic and often inscrutable submarine trench deposit from the Taconic subduction zone that makes up much of the local bedrock. Here, a phenomenal array of textures, exotic inclusions, mega stratification, volcanic detritus, and metamorphic features can be seen together at a clarity and scale unlike anywhere else, providing insights into the origin of this enormous sedimentary melange.

Key Topics: Ecogeology; Georgetown Intrusive Suite; Sykesville Formation; Pleistocene and Holocene history of the Potomac Gorge; weathering, ground water, and nutrient cycling; flood frequency and dynamics

Field Trip Details: Hike departs promptly at 9:30 AM from lot C-1 at Turkey Run Park, and will follow the Potomac Heritage Trail towards Dead Run, returning to the parking lot by around noon. Eat lunch at the picnic area overlooking the old soapstone quarry at Turkey Run, before driving across the river to Chain Bridge Flats. Afternoon hike will depart around 1:30 from the parking area on Clara Barton Parkway immediately north of Chain Bridge, and will follow the towpath and ACE spillway out to the flats. Return by 4 PM. Expect spring wildflowers, poison ivy, some steep grades at Turkey Run, and rough terrain involving scrambling on rocks at Chain Bridge Flats. Sturdy footwear is a must. Bring lunch, snacks, and water. Restrooms are available at Turkey Run Park, but not at Chain Bridge Flats.

Questions? Contact Bill Burton at bburton@usgs.gov

Labels: field trips, gsw, piedmont, plants, rivers

What's going on here?


(Michelle Arsenault of NSF for scale)







First person to answer correctly wins a "GEOLOGY ROCKS" bumper sticker!

Labels: contest, plants

Lichens are symbiotic associations between fungi and algae. The fungus provides the alga with a place to live, and the alga photosynthesizes and shares some of the resulting 'food' with the fungus. One provides room; the other provides board. It benefits both species to hang out together, and provides a nice example of two phylogenetic 'branches' of the 'tree of life' merging into one. There are many varieties of lichens, living in a diversity of habitats, but they're easiest to spot in colder zones where they are first in line to colonize raw rock surfaces.

When I was in Ecuador in January, I saw a lot of lichens, and took some photos of them. I'm not a lichen expert, and I won't attempt to name these varieties. I'm more interested in them as aesthetic phenomena. I find them beautiful.

This one reminds me of ripples on a pond's surface, spreading out over decades and centuries:


The orange here is also a lichen:


These wispy lichens were three-dimensional structures that were found all over the ground surface (not encrusted on a rock) in the paramo ecosystem.


They were present in such profusion in Cotopaxi National Park that the ground looked from a distance as if it had a light layer of snow on it:


Other ground lichens:




Lichen-bearded goofball:

Labels: ecuador, fungi, humor, plants, south america, travel

As you'll recall, when I left off with my Ecuadorian travelouge, Lily and I had summited Pasochoa, and then taken a day-hike in Cotopaxi National Park. Next up, a new mountain that has about the same elevation as Mt. Whitney (highest peak in the lower 48 United States): about 14,500 feet. To climb this extinct volcano called Ruminahui (Roo-min-ya-wee), we headed up a ridge between two adjacent glacially-carved valleys.















Me with clouds and background glacial valley:


Diego (our guide) on the trail:


Up on top, there was less vegetation, but more cloud... and snow was falling.

The bedrock was a volcanic breccia that had been cut by numerous andesitic dikes:






You can see some blurry snowflakes in the previous photo. Here's a cold-looking Lily with her boots on an andesitic dike:



Here's a couple of close-ups to show the cross-cutting relationships between the andesite dikes and the volcanic breccia:





Here's a short, not-especially-great video wherein I point out a few things that don't really show up all that well. Still, you get to see it snowing!

A big "thanks" to NOVA's king of digital video, Richard Attix, who helped me rotate this video and crop out some unintended footage from the raw video we shot on the mountain that day.

Cold hikers:



"Sheesh! It's cold up here!":



On the way down, we also took some time to check out the plants. Here's one called "Orejas de conejo" ("Ears of the rabbit"):

Here's one that smells exactly like chocolate!


In fact, Lily was able to harvest this chocolate bar from it!

Okay, not really. It's money that grows on trees, not chocolate bars.

So that's the story of our second successful summit... now there was only one more to go... the legendary Iliniza Norte. Photos from that hike in a couple of days...

Labels: ecuador, glacial landforms, mountains, plants, sediment, south america, travel, volcano

We now return you to our originally-scheduled photo-travelogue...

On the second day of our Andean mountain tour in Ecuador, Lily and I set out from Tambopaxi Lodge, our comfortable accomodation in Cotopaxi National Park:



We were going for a day-hike, checking out the scenery with our guide Diego while we acclimatized for some more serious mountain climbing in the days to come. The official goal of our hike was to check out two naturally-flowing cold springs, where the agua was pura, and safe to drink. Here's the first one, issuing from the base of a lava flow, with me awkwardly twisting around to raise a bottle of the good stuff:



Spring #2, of greater volume:


Some shots of the scenery:







The extinct volcano Sincholagua:


Me with Sincholagua (and lower cloud cover) in the distance:

A look back at Pasochoa, which we had climbed the day before:


And Cotopaxi itself, the charismatic, active volcano which draws most people to the park:


Critters:

A big insect, maybe a grylloblattid?


Feral horses:


We also saw some cool "primitive" plants (plants with ancient lineages):

Liverworts:


Sphenopsids:


Club mosses:


There was also some geology going on...

Here's a handful of loose lapilli (mixed in with some organics):


Stream deposits on the flanks of Cotopaxi Volcano, showing different water energy regimes. The coarsest layer in the middle represents the fastest moving water (capable of carrying larger particles of sediment):


And here's some flow-banding in andesite:


It started raining on our way back to the lodge, but that was okay, because hot showers and warm tea awaited there. Acclimatization, check! Next up, the peak known as Ruminahui...

Labels: arthropods, critters, ecuador, geology, mammals, plants, south america, travel, volcano

You know what feels really good when you're feeling sick? A hot bath.

And so, when it came to pass that over the winter break, I flew down to Ecuador with a recovering case of pneumonia, my friend Lily and I opted to put our mountain-climbing plans on hold, and go sit in some hot water instead.



From Quito, we took a public bus ($2) an hour east to a series of thermal pools at Papallacta ("papa yacht uh"). This is a lovely resort, nestled in a lovely valley:



Inside the resort (>$2), the architecture was fused with the landscaping in some interesting pseudo-natural ways. For instance, this is in the lounge, where the rocky wall rises up, but then stops some distance below where the wooden ceiling begins. The interval is filled with glass, but the illusion is that the building is open to nature.



They've got nice grounds, too. An organic garden is featured, and they have some neat sculptures. This one is clearly inspired by Andy Goldsworthy.



But there was a mystery... The local river, which carved the valley, was cold:



...So where did the hot water come from? We had noticed some steaming pools on the bus ride over the Andes, at higher elevation. Taking a walk on our second day there, we saw this aqueduct coming down the mountain into the valley:



Aha! It must be that they are pulling the hot water out of the actual hot springs up above, then piping it down to Papallacta for people to enjoy.

Papallacta is just south of the Equator:



At the Equator, Papallacta's elevation of ~10,000 feet (~3300 m) is quite pleasant. A tad chilly when it's dark or overcast, but the snow was at a higher elevation still:



Hiking around in between soaks in the lovely hot water, we saw hummingbirds galore, including the bizarre sword-billed hummingbird, which has a beak longer than its body (Google it to see!) We also saw some cool critters, like this beetle:



...And also some cool plants. Lily's really into plants, but even I can appreciate their numerous and varied forms, especially in as biodiverse a place as Ecuador...



Flower-on-a-stem, within a leaf:



After soaking and resting and acclimatizing at Papallacta, I felt a lot better and we trooped back to Quito to meet up with our guide and start climbing mountains... More on that in posts to come.

Labels: art, arthropods, birdies, critters, ecuador, hot springs, plants, south america, travel

There's more than rocks in Hawai'i. Another thing that might catch the naturalist's eye is the diverse suite of interesting animals and plants. Today, I'd like to share some images of neat lifeforms I encountered on my Thanksgiving trip to the big island. I'll start with sea turtles, then move on to jellyfish, crayfish, endemic freshwater fish, chameleons, wooden tiki carvings (not technically alive), and plants.

Let's start with the turtles. These are green sea turtles, and they're pretty common in Hawai'i. They have certain beaches they frequent, where they haul themselves up and out onto the beach to rest. Here's one at Pu'uhonua o Honaunau National Historical Park:


Here's one feeding on algae at Punaluu Harbor:




Video of the same foraging turtle:


A short distance further along the shore, a snoozer:




But there's more in the sea than turtles... On a hike to the Polulo Valley, we found half a dozen small "Portuguese Man O' War" jellyfish on the beach:




A few valleys down, we spied these native crayfish and freshwater fish in a stream:


One of the real charmers is an invasive species, the Jackson's chameleon, native to Africa:




Look at those hands! Three "thumbs" and two "fingers."


Males have three prominent horns on their heads:


Video:




Baby Jackson's:


Do these count as "critters"? Not sure where else to put them... Tikis outside the chief's house at Pu'uhonua o Honaunau National Historical Park:


And lastly, a couple of botanical images:

Labels: anthropology, critters, hawaii, plants, travel

My friend Jennifer Soles appeared on NPR's All Things Considered last night, discussing the current low acorn count that was mentioned over the weekend in the Washington Post.

Labels: news, plants

...from my apartment window!

Here's a series of photographs I've taken over the last month and a half to document the change in the leaves on the trees. I'm a big fan of repeat photography to document changes like these.





























































Maybe I'll do the reverse of this project in the spring to watch it greening up again...

Labels: dc, plants

Yesterday, I pulled up the Venetian blinds in my office window at NOVA, and this is what I saw:


Naturally, I had to take a photograph. It's puuurty.

While I had the camera out, I figured I'd shoot a few photos of the rest of my office, since it's full of all sorts of interesting clutter. Rather than explaining what all the doodads are in these photos, I figured it would be more fun to just post them and see if you can identify them all:















Have fun!

Labels: fossils, igneous, maps, metamorphism, minerals, nova, plants, sediment

Much of the geoblogosphere has been posting about trees over the past couple of days.

I'll just make a brief contribution here, showcasing some of the incredible fall foliage seen down near Konnarock, Virginia, while my students and I were down at the Virginia Geological Field Conference a few weeks back:

Labels: plants, virginia

Last weekend, I went out to the Virginia countryside to harvest some fruit. Several of my college friends have farms out there, with organic fruit free for the picking each fall.

Just thought I would share a couple of images...

Here's my cat Lola checking out a tarp full of ugly but delicious apples:

Last year, I harvested a huge number of apples and pressed them into cider, and fermented 8 gallons to make hard cider, which was pretty good. Or at least drinkable, if not exactly "good." This year, the orchard at Smithfield Farm was far less fruitful, so I only managed 3 gallons of cider.

The good news is that Orange Springs Farm hosts a mature pear tree that was heavily laden with fruit, and I collected a good sixty pounds or so of pears. Once these ripen, I'll turn them into cider too:


The harvest bounty matches up nicely with our recent cool weather. Fall is my favorite season, and now the leaves are starting to senesce and the nights are crisp and cool. Good sleeping weather. On a field trip this weekend up to Shenandoah National Park, the sumac and the Virginia creeper had already turned scarlet, and the deciduous trees won't be far behind. Happy autumn, everyone!

Labels: lola, plants, travel, virginia

I must recommend a couple of videos to any science educators out there. (I just watched the last of them last night.)

A Private Universe was an eye-opening half-hour video that was followed by a short series called Minds of Our Own. (Links go to video on demand from Annenberg Public Media.) Both titles follow a similar format, and pursue similar content. Their subject is the difficulty in getting students to learn science. Both videos make the hypothesis that the major obstacle in science education is not complexity, or abstract reasoning, but pre-existing ideas about the way the world works. Students come into our classrooms with certain notions, and unless we teachers (a) know what those notions are and (b) explicitly confront them, then the students' natural reaction is to stick with their perfectly-reasonable ideas about the way the world works (and reject the scientifically valid ideas about the way the world works).

A Private Universe opens with a scene of Harvard's graduation, and the filmmakers interview the gowned students about the phases of the moon. Full moon, half moon, new moon, half moon again... Why does the moon have phases. Everyone shown indicates they think that it's the shadow of the Earth on the moon that give it its phases. In Minds of Our Own, similarly shocking scenes unfold wherein the graduates of MIT can't use a battery and wire to light a lightbulb, and again where Harvard graduates are tested, this time on the subject of trees. A tiny seed grows into a massive tree: where does all that weight come from? All those interviewed thought the tree's mass came from the soil (as opposed to CO2 in the air). It's really something to see -- some of the brightest students in the country, demonstrating a basic scientific illiteracy.
Subsequent one-on-one interviews with elementary, middle, and high school students probe for deeper understanding of just what these students think is going on. Some of these interviews yield bizarre interpretations of reality so that the student can match their erroneous worldview with their well-developed logic and reasoning. It's quite striking to see the lengths they will stretch their minds to, in order to accomodate their pre-conceived notions. A Harvard education professor (Philip M. Sadler) who is interviewed in the films says "The most important thing we can do as teachers is find out what our students already think when they walk into the classroom" (paraphrase). You can be an extremely skilled intstructor, in other words, but this basic step is essential. If you don't assess your students' understanding before you teach them, you're setting them up for failure. Students must be confronted with their false views and shown why they are false, if they are to open their minds to other possibilities.

One of the most gratifying scenes is when a young man is explaining why pressure increases in a closed piston. At first, he thinks that because the volume is less when the piston is compressed, it must contain less air. But as he's illustrating this notion, and being asked clarifying questions from the interviewer, you can see him realize that the same number of air particles must be in the piston when it is both extended and compressed: they're just closer together when it's compressed!

From the perspective of an educator, the depressing side of this realization is that we have nowhere near the amount of time it would take to have one-on-one conversations with every student to explore their misperceptions and then gently lead them through a line of logical inquiry to correct those ideas. That takes some serious time. Is there a more efficient way to root out these ideas? I'm not sure.

Has anyone else seen these videos? I was very impressed. Now I'm wondering how best to incorporate this new perspective into my own teaching...

Thanks very much to Nicole LaDue (NSF) for sending a DVD of these videos my way.

Labels: astronomy, movies, plants, teaching, tv

This was the scene at the campground I stayed at this summer on my first day south from Bozeman to Las Vegas. This is a campground south of Huntsville, Utah, in the Wasatch range west of Ogden (map).

It's not snow you see on the ground, despite being white stuff that accumulated in a layer several inches thick, and blew into drifts like snow would.



These are the seeds of the cottonwood tree (Populus fremontii), which like dandelions, have a bunch of fluff emerging from them to catch the wind. This allows the species to spread its range by letting the wind carry its seeds to new locations. While cottonwoods are ubiquitous in wet areas of the west, I've never seen this kind of accumulation of cottonwood fluff before.



It was like warm snow -- quite magical to see.

PS - Prius note: The fuel mileage out west this summer wasn't as good as the regular commute back home in DC, but it was still pretty good. The total roadtrip (~10,000 miles) ended up averaging 52.6 miles per gallon of gasoline. Can't complain about that.

Labels: plants, prius, travel, utah

Sorry for the lack of posting lately -- end of the semester crunch.

Just thought I'd post a link today, to an article in today's Times looking at some of Charles Darwin's botantical experiments.

Also, if anyone's in the neighborhood, I'll be giving a talk at the National Science Foundation in a couple of hours: "Geology Along the C&O Canal," starting at 12noon at NSF headquarters in Arlington, VA. Free & open to the public. Come one, come all... Sorry for the late notice.

Labels: evolution, plants