Rested up from Day 1 in Torres del Paine, we were pleased to see that day 2 dawned bright and sunny.

Lily takes a morning break to shed layers:

The weather in Patagonia was really variable, as was the trail. This meant that all day long, we were stopping to put on layers or take off layers as we got cold or hot. It was kind of a pain. Whine whine whine.

All day, clouds scudded along, but we didn't get any rain until late in the day. The main part of the Paine massif was coming into view. Here's a shot from noon-ish:


Here's a shocker: ...We saw more rocks!

Here's another graded bed:


And a little plumose structure, showing a nice twisty hackle fringe:


When I first saw this outcrop, my brain's pattern-recognition center peeped: "CRINOID STEMS!"

...But upon closer examination, they lacked pentameral symmetry, and were some were kind of lumpy. And considering the main rock here is Cretaceous-aged, crinoids could be present, but they aren't as likely a candidate for fossilization as they would have been if these rocks were Paleozoic. So I think these were concretions of some kind. Chert? I shared this image with Patagonia geology expert Brian Romans, and he pointed out something I hadn't noticed in this image: the flame structure in the lower left. That indicates this boulder is upside-down, relative to its original depositional position.

Here's another concentrically-zoned jobbie, which I interpret as a concretion. Overall, this thing was like a pig-in-a-blanket, but on steroids:

I think it's a flint nodule. Brian hasn't seen any crinoids or any concretions in these rocks, so I'm at a loss to offer further explanation.

I was flummoxed by this one, too:

This time, the pattern-recognition center wanted it to be a trilobite, but that's impossible (or, strictly speaking, not impossible but history-re-writing-able) in these aged rocks. Brian tells me it's almost certainly an inoceramid bivalve. That works for me.
(...Or could it be... pseudosegments???)

We walked on, through fields of little white flowers:


Angling towards the main massif, more gnarly peaks came into view...


One thing you can see well in this shot is the contrast between the color of the darker Cretaceous-aged sedimentary host rocks (turbidites) and the light-pink-colored granite which intruded them around 12 million years ago (Miocene).


A bit further on, we could get a decent look at the intrusive relations (through binoculars):

(In this annotated photo, "T" is for "turbidite," "Gr" is for "granite.")

We dropped down off a moraine towards Refugio Dickson, where we made tea, rested a bit, and pushed on again...


At the head of Lago Dickson was an impressive looking glacier, dropped down out of the South Patagonian Ice Field and into the lake:


It was around 1pm when we got to Dickson. We were tired, but the day was only half over. We decided to push on, and essentially do two days' hiking in one. Next stop: Refugio Los Perros!

We hiked on through PRIME Magellanic woodpecker habitat, and it just KILLS me that I didn't see one there, though I did see a few other new birds. Then the rain started, and we started to get tired. But we were committed at this point... We pushed on, and on, and on, and on, climbing up through a forested valley, until finally we popped out on fresh glacial moraine, and saw this:

That's the Los Perros Glacier! A short distance further up the valley was the campground. At this point, the rain had morphed into snow, blasting us in the face as we slogged along, really looking forward to dinner and sleep. Maybe not in that precise order. Eventually, we got there.

Fortunately, the clouds parted for literally 5 minutes, and we were able to have our portrait taken by a doctor from Santiago, who was hiking there for Christmas with his family. They were literally the only Chileans we met who were in the park as tourists (i.e., not park employees or concessionaires) our entire trip. I think we look happy to be in such a special place, don't you?


Next up: Day 3, when we cross John Gardner Pass and see the Grey Glacier for the first time!

Labels: chile, cretaceous, fossils, glaciation, granite, miocene, mountains, patagonia, primary structures, sediment, structure, travel

From Puerto Natales, we took a bus with other backpackery types north to Torres del Paine National Park, the main object of our trip. It was a bit rainy when we left the bus and walked off into the park, aiming to complete the Grand Circuit, a 7-day, 100-km hike around the Paine Massif. Heading down the trail:


Google Map of the Paine Massif, the main focus of the national park:

It's a little offshoot of the main Andean cordillera, a relatively isolated block of mountains rising from the Patagonian steppe. The park is named for some towers ("torres" in Spanish) in the eastern part of the massif. The word "paine" ("pie-nay") apparently means "light blue" in the pre-Spanish native language. This is apparently because many of the lakes (so prominent in these maps) are light blue in color due to the large influx of suspended glacial "milk."

Here's the specific route we took (approximately) in blue:

We hiked in a counter-clockwise direction.

So we started off over in the eastern part of the park, headed north by northwest. We were hiking through steppe, with the snow-covered mountains rising to the west:


...But wait, what's that on the horizon?

Guanacos! These are camellids -- related to the better-known llamas of Peru.

Thumbs-up for guanacos!


The rocks of Torres del Paine are mainly Cretaceous-aged turbidites (shale, graywacke, and conglomerate), intruded by granitic magma in the Eocene. All along the whole trip, I was drooling over the many beautiful graded beds I saw. Here's the first photogenic graded bed I found, with the paleo-top of the bed at the top of the photograph:


These rocks of the Cerro Toro Formation were deposited in the Magallanes Basin, a Cretaceous to Paleogene retroarc foreland basin. Brian Romans of Clastic Detritus shared some information with me before I went down to Patagonia, and I am indebted to him for the insights I gleaned from that sharing. However, any errors in identification or interpretation are my own. According to the model of Romans, et al. (2009)*, a fold and thrust belt was operating to the west, and an elongate north-south oriented submarine trough flexed downward east of that during the Cretaceous. Mud and sand and gravel flowed into this sedimentary basin mainly from the north in three phases which can be contrasted readily with one another in terms of depositional style and confinement of depositional area. These three phases of deposition correlate to different facies, and are exposed well in the area north of Puerto Natales due to subsequent deformation and uplift (not to mention recent deglaciation).

I'm a structural geologist, and deformation is what I am all about, but I honestly didn't expect to see much structure when in Torres del Paine. (I was eagerly anticipating the graded bedding, though!) So it was somewhat shocking to see some very deformed turbidites on that first day of hiking. Here's me standing on the edge of the Paine River, surrounded by tilted turbidite strata:


...And this stuff was really messed up:


Zoomed-in, you can see some severe folding and faulting having shuffled up these rocks:


We hiked about six or seven miles that first day, and camped at a place called Seron. The park has set up these dozen or so campgrounds where you are allowed legally to camp. Some are free, some cost a few bucks. Seron cost about $8 per person to camp there, but we got hot showers with that cost: Nice! The sun set on our first day, and we slept well.


More soon, on our second day of hiking...
____________________________________________
* Romans, B.W., Fildani, A., and Hubbard, S.M., 2009. "Controls on Deep-Water Stratigraphic Architecture," in Stratigraphic Evolution of Deep-Water Architecture: Examples of controls and depositional styles from the Magallanes Basin, southern Chile, SEPM Field Guide No. 10, p. 7.

Labels: chile, cretaceous, eocene, mammals, maps, national parks, paleocene, patagonia, primary structures, rain, sediment, snow, south america, structure, travel

Mass Graves of the South Dakota Inner Sea

Location: Calvert Marine Museum Indoor Auditorium, Solomons, MD
December 5, 2009 2:30 PM

FREE Public Lecture in the museum auditorium

Join Bill Palmer presenting "Mass Graves of the South Dakota Inner Sea."

Approximately eighty million years ago, periodic volcanic eruptions to the west of the South Dakota Inner Sea carpeted hundreds of square miles with ash. Some of this area was purchased by the U.S. government in the 1960s because a vast number of fossils are found there in rock layers known as the Pierre Shale. Some of the fossiliferous layers are over 30 feet thick. These layers now preserve the skeletons of thousand of marine reptiles, pterosaurs (i.e., the extinct flying reptiles), sharks, and fishes.

Hosted by the Calvert Marine Museum Fossil Club and sponsored by the Clarissa and Lincoln Dryden Endowment for Paleontology. For additional information, please contact Stephen Godfrey, CMM's Curator of Paleontology, at 410-326-2042, ext. 28.

Labels: cretaceous, fossils, maryland, meetings, sediment, south dakota, volcano

After a post the other day, Michael wrote in to ask for clarification of "Pumpelly's Rule."

AGI defines Pumpelly's Rule thusly*: "The generalization that the axes and axial surfaces of minor folds of an area are congruent with those of the major fold structures of the same phase of deformation."

We saw some of this same idea expressed in yesterday's annotated photo series featuring parasitic folds on larger folded (and boudinaged) quartz veins. There were bigger folds there, and then those bigger folds were decorated with little parasitic folds. The idea behind Pumpelly's Rule is that you could get a sense of what the big folds are doing by looking at the little folds. But even more revealing than parasitic folds at the hinge area of a larger fold are the little folds that you sometimes see on the limbs of bigger folds.

Depending on the sense of the asymmetry of these folds, we call them either "S" or "Z" folds. The parasitic folds are more symmetrical towards the apex of the fold, but more asymmetrial along the limbs. Check out this diagram to see how small S-folds and Z-folds relate to the larger structure of the main fold. Blue arrows indicate the relative sense of shear on each limb of the main fold:


Pumpelly's Rule suggests that we don't need to see the whole picture to understand what's going on. Simply seeing the areas of the diagram highlighted in red are enough to give a sense of the bigger picture.

So how does that relate to this photo, which prompted the question?


Behind me in the photo, you can see an outcrop of the Cretaceous-aged Thermopolis Shale, exposed on Bridger Canyon Road, in the southern part of the Bridger Range, Montana. It has some sandstone layers in it. These sandstone layers, with their high color contrast against the surrounding black shale, record a series of lovely S-folds. The strata here dip moderately to the west. The S-folds relate the sense of shear on the larger structure of the Bridgers: they suggest that the bedding here is overturned, and that you're looking at the eastern side of a big north-south-striking anticline. In the southern Bridgers, therefore, the overall structure is an overturned anticline. Hiking west & uphill confirms this interpretation stratigraphically: as you go up, you go "back in time," encountering older and older strata: from the Thermopolis into the Kootenai, into Jurassic formations like the Morrison, the Swift, and the Rierdon.



Moral of the story: small observations can have large implications.

Raphael Pumpelly made this observation in 1894, presumably during his tenure as the head of the USGS New England Branch. Pumpelly sounds like he was an interesting guy, leading expeditions in Asia when that was a seriously sketchy prospect. In addition to his Rule, he is honored with a mineral named after him, pumpellyite.

* If you don't have a copy of AGI's Dictionary of Geological Terms, a good resource for looking things up online is this Dictionary of Mining, Mineral, and Related Terms sponsored by Hacettepe University in Turkey.

Labels: cretaceous, history, jurassic, montana, mountains, structure, websites

I saw Ray Stanford, an enthusiastic amateur paleontologist, speak last month at a meeting of the Paleontological Society of Washington.

It was my first PSW meeting, and I got a warm welcome from PSW president and University of Maryland paleontologist Tom Holtz, who gave a specific shout-out to NOVA Geoblog, encouraging the ~30 attendees to check it out. (If you're arriving as a consequnce of that endorsement, welcome!) Four of my Honors students joined me for the talk. Just getting to go behind the scenes at the Smithsonian is a treat in itself. From the Easter Island moai in the Constitution Avenue lobby of the museum, we were escorted through labyrinthine passageways to the Cooper Room. Our route brought us past immense fossil collections, cossetted away in row after row of cabinets. It was enticing, and made me resolve to arrange a special tour there sometime for the Honors students.

The point of the talk was Stanford's immense collection of fossil dinosaur tracks (and at least one apparent mammal track which is quite large: raccoon-sized at least, with apparent dinosaur skin impressions right next to it). It used to be thought that Maryland only had Triassic/Jurassic fossil tracks, from the Newark Supergroup rift valleys that opened up during the breakup of Pangea / opening of the Atlantic Ocean. Stanford has made a real scientific breakthrough by demonstrating that there are early Cretaceous-aged tracks in the area too.

None of his Cretaceous-aged tracks are collected in situ. Instead, he finds them all as "float" (weathered-out loose blocks) in streams draining exposures of (what I infer to be) the Patuxent Formation. (He didn't specifically mention source formations that I heard during the talk.)

He's found a ton of stuff! Actually,if I'm being literal, he's found tonS of stuff! And he stores it all in his living room! He recently had the foundations of his house reinforced because he has so much STUFF. Hundreds of tracks, and other fossils, too. Whoa! This guy does not play by the same rules as most folks.

There were a lot of coprolites mentioned, including:

• a 98-pound coprolite (!)
• a coprolite with a dinosaur footprint in it
• a dinosaur footprint with a coprolite in it

He also shared what he claimed were skin textures preserved in tracks. Some were self-evident, and I readily accepted them as valid. However, others weren't visible to the naked eye, and he only "demonstrated" them with Photoshopped images wherein the contrast dial was turned up to 11 -- I think this "technique" generated patterns that resembled skin impressions, but when I looked at the fossil itself, they were nowhere to be seen. I am dubious about this particular claim.

The talk gave me lots to think about, but not so much about dinosaur lifestyles or anatomy so much as the role of amateurs in science. Here's a guy with boundless enthusiasm, and he's finding stuff that the books literally said didn't exist. His efforts have resulting in expanding Maryland's Mesozoic paleontological record into the Cretaceous, and he's found all sorts of stuff that's super-duper interesting, like that mammal track.

Stanford was profiled last year in Geotimes magazine, before it switched its name to EARTH. Discovery News also ran a story about his findings. Interestingly, when Googling his name for this blog post, I also came across some other wacky stuff he's involved in, including UFO's. This definitely jibes with the lack of scientific rigor that I perceived in his presentation. (Quote from the interviewer: "In the 1970s, Stanford was the moving force behind the Association for the Understanding of Man (AUM) and Project Starlight. The former an attempt to decipher the UFO enigma by psychic means, the latter using advanced scientific instruments.")

So, having learned this, what do I make of his paleontological data? The best I can come up with is to trust my own eyes and view his claims open-mindedly but with the traditional scientific filter of skepticism. I accept the coprolite data; I found it self-evidently convincing. The skin-texture data? Not so much. The UFO stuff? Don't get me started...

Labels: coastal plain, cretaceous, culpeper basin, fossils, maryland, meetings, mesozoic, museums, psw, science and society, smithsonian

PALEONTOLOGICAL SOCIETY OF WASHINGTON

Maryland's Lower Cretaceous Vertebrate Tracks and Trackways
by Ray Stanford, Maryland Track Project

Wednesday, April 15, 2009
7:00 p.m., in the Cooper Room, National Museum of Natural History
10th St. & Constitution Ave. Meet in the Constitution Avenue lobby at 5:00 p.m. if you wish to join us for dinner, at the Elephant and Castle, NW corner of 12th & Penna. Ave., NW

Non-Smithsonian visitors will be escorted
to the Cooper Room at 6:30 and 6:55 p.m.
Remaining Date for 2008-2009 Season: May 20

Labels: cretaceous, fossils, maryland, psw, smithsonian

Here's a fossil that I have hanging around my house; it's an ammonite from the Bearpaw Shale (late Cretaceous) of eastern Montana. I collected it just south of Glendive, Montana, this summer on the "Dinosaur Paleontology of the Hell Creek Formation" class I took through the MSSE program at Montana State University.

Overall, this little fellow has a maximum diameter about the same size as a quarter:


On the back side, where the nacre has been broken off, you can see the suture patterns:


Clearly, these are ammonitic sutures (as opposed to ceratitic or goniatitic), but I haven't identified it to genus level. Any paleontologists out there able to help me out with an ID?

Labels: cretaceous, fossils, montana, msse

It's that time of the semester, when the field trips are over, and the field trip essays start rolling in. These papers I assign are intended to be syntheses of the field trips I take my students on. I want them to interpret the landscape as a geologist would, and support each claim about geologic events in the past with supporting evidence observed or discussed on the trip.

I offer my students the opportunity to submit a rough draft of their field trip paper, and then I give them feedback about both content and formatting/writing style, so they have a chance to revise before submitting a final draft. Each semester, about a quarter of the students avail themselves of this opportunity for feedback before the "real" paper is due. Giving them quality feedback is a time-consuming process, but I feel it's important both to cement geologic concepts in their minds, and to guide them in developing their writing skills.

Accordingly, it's been a slow week for posting on this blog. I've been too busy with work. However, this morning it occurred to me that I could capitalize on my grading efforts by sharing a student essay with you all, edits and all. Why do I think you'll be interested in such a thing? (A) I think it gives some insight into the practice of teaching geology at the introductory college level, and (B) I think this is an excellent rough draft for an essay about Washington, DC's geologic history. The student's name, of course, has been redacted:

Labels: cretaceous, dc, geology, nova, ordovician, teaching

Today: a few photos of neat stuff from the Sternberg Museum of Hays, Kansas. These are from my first time through Hays this summer, in June. It's worth a stop. Some of these are from their permanant collection, and some from a travelling exhibit of fossil reconstructions called "T. Rexcetera."

Archelon, mega turtle of the Western Interior Seaway


Pterosaur -- the flying Chihuahua of its day


Plesiosaur (I like how fierce this one looks, and the contrast in colors between its teeth and its bones -- reminds me of the Joker in the Batman movies...)


Big honkin' mosasaur skull (Tylosaurus? I should have taken better notes...)


Yipes! Under the Sternberg's dome, there are reconstructed beasties...


Beautiful slab of Uintacrinus, a stalkless crinoid (more here)


I think this last one is so beautiful that I just switched my desktop background image to it (from the previous image, a geologic map of the Moon).

Labels: chalk, cretaceous, fossils, kansas