Labels: arizona, art, books, delaware, maine, maps, new jersey, pennsylvania

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

Started by Lockwood, perpetuated by Silver Fox... [UPDATE: Geology Happens, Geotripper, Hypocentre & Phreatic Ramblings have chimed in, too. The latter even posted about a huge paleofalls...] As per the geoblogospheric standard, the idea is to bold the ones you've been to.

#10 Lower Calf Creek Falls, Escalante National Monument, Utah
#9 Lower Falls of the Yellowstone River, Yellowstone National Park, Wyoming
#8 Upper Whitewater Falls, in southwestern North Carolina
#7 Snoqualmie Falls, between Snoqualmie and Fall City, Washington
#6 Havasu Falls, Supai Village, Havasupai Indian Reservation, Grand Canyon, Arizona
#5 Shoshone Falls, Twin Falls, Idaho
#4 Multnomah Falls, Columbia River Gorge, Oregon
#3 Bridalveil Falls, Yosemite National Park, California
#2 McWay Falls in Julia Pfeiffer Burns State Park, Big Sur, California
#1 Niagara Falls, Niagara, New York

Bonus Waterfall #1 [via Lockwood]: Salt Creek Falls, Oregon
Bonus Waterfall #2 [via Silver Fox]: Palouse Falls, eastern Washington
Bonus Waterfall #3 [from me]: Deer Creek Falls, Grand Canyon, Arizona (photo above)

For the record, I kind of don't get the appeal of waterfalls. I mean, they're cool and all, but they don't strike as particularly complex (and therefore, not particularly interesting)... I mean: gravity, right? ...It pulls water downhill... What's the big deal? (I had a conversation this summer along these lines at Waterfall #9 on this list, with a similarly-minded fluvial curmudgeon.)

...But people love them - When I poll my Physical Geology students at the end of the semester about what their favorite part of our Billy Goat Trail geology field trip, only a third or so invoke the migmatite, a third or so cite the physical challenge of climbing "The Traverse," and a third or so claim that viewing Great Falls was their favorite part. To each their own, I reckon: I'm glad they got something meaningful out of the trip... but I can't claim to understand it.

In my twisted worldview, Deer Creek Falls is interesting not merely because it's scenic (and a great place to go swimming), but because the waterfall issues from the Great Unconformity, and thus has geologic significance: It satisfies the intellect as well as aesthetic sensibilities.

Labels: arizona, california, grand canyon, new york, wyoming

When critters interact with their environment, sometimes they leave behind traces of that interaction. If we're lucky, these traces fossilize and can be preserved through time to tell us interesting things about the past. This past summer, when I rafted down the Grand Canyon with my father and two brothers, I saw some cool trace fossils. In chronostratigraphic order (earliest first), here they are:

The Bright Angel Shale can be found atop the Tapeats Sandstone, and below the Muav Limestone along the river in much of the canyon. The Bright Angel is middle Cambrian in age. For my money, it's one of the most spectacular sedimentary layers there, because it's so varied. The colors of the individual strata range from purple to green to brown to tan, and they are in many places chock full of horizontally-oriented feeding traces. Here's some of those wormy shapes along the trail to a waterfall we hiked to... (sorry, don't remember the name or exact location... I think it was day 4 or so of the overall trip... Hmmm, I guess I should have blogged this in early July when I photographed it...)





Nearby, we saw a spectacular trilobite crawling trace (Cruziana?):



Earlier in the trip (day 1, at lunchtime), and higher in the stratigraphic stack (the Permian Coconino Sandstone, which is a sand dune deposit), we saw these reptile (synapsid?) footprints:



This is a trackway left by an ancient reptile as it was walking up and down the dunes, preserved on the slip-face (which defines the feature we recognize from a side-view as "cross bedding"), and now, 260 million years later, I'm viewing those same tracks from underneath, as the older slip-faces of the dune have peeled off, and only the overlying (younger) ones are preserved in this particular alcove. Pretty spectacular stuff. And it offers some nice lunchtime shade, too... Can't complain about that. Here's another shot, with a sense of scale in it:



You can see the individual toes! Wild!

Labels: arizona, cambrian, fossils, grand canyon, permian, primary structures, travel

Another book I read over the winter break was Canyon Solitude, by Patricia C. McCairen. It's a travel book about one woman's solo journey down the Colorado River through the Grand Canyon. It's one of those books that derives its structure from a journey, but it includes plenty of asides, mainly about the author's longer-term personal journey through life. It's rich in a kind of feminine soul-searching which may appeal to female readers, but as a male, I kind of didn't "get" that part. That being said, I'm a fan of travel books, and it was a pleasant enough read. I think it resonated more with me than it would with the average bear because I spent a week on the same journey this summer. Overall, I'd give it 3 stars out of 5 possible.

Here's a link to the book on Amazon.

Labels: arizona, books, grand canyon

Over the winter break, I read the new book Ancient Landscapes of the Colorado Plateau, by Ron Blakey & Wayne Ranney. This is an excellent read, and a terrific introduction to the geologic history of one the world's most dramatic landscapes. Blakey's maps have been featured on this blog before, and he has been kind enough to allow me to modify some for use on my field course websites (like here and here and here). The book goes through geologic time and makes extensive use of beautiful paleogeographic maps to reveal the story of mountain-building, transgression, regression, sand-dunes, faulting, volcanism, and erosion that characterizes the Colorado Plateau. It's not just paleogeographic maps, by the way: there are also plenty of shots of fossils, Colorado Plateau landscapes, and comparable modern depositional environments to enliven the story. It's a graphic story, well told with excellent graphics. I recommend you get yourself a copy if you've ever been to the Colorado Plateau, or if you ever plan on going there.

Find the book: On Amazon ... At the NOVA library

Labels: arizona, art, books, colorado, maps, new mexico, utah