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...
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* 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

A block and half away from my new condo, there stand a trio of imposing churches, at the corner of 16th Street NW and Columbia Road NW. A Google Map of the corner in question:


The one I want to discuss today is on the southwestern corner of this intersection. It's currently a Unification Church, but the structure was built in 1933 as the first chapel of the Church of Jesus Christ of Latter Day Saints (the Mormons) in DC. According to Chris Barr, an attorney and amateur paleontologist who is compiling an "Accidental Museum of Paleontology" about DC's building stones that include fossils, "two grandsons of Brigham Young contributed to its design and artwork, and the church consciously echoes the design of the Mormon Temple in Salt Lake City." Not only that, but they opted to use exterior buuilding stone shipped in all the way from Utah!

Chris's website about all the fossil-containing DC building stones is nearing completion, and I will post a link here when it is live. In the meantime, I wanted to share some of the information he compiled about the rocks which makes up the exterior of the Unification Church: Utah Bird's Eye "Marble."

Here's what it looks like:


The elliptical shapes you're seeing here are oncolites (sometimes called "oncoids"), and they are essentially little ellipsoidal stromatolite balls. A little grain of this or that gets encrusted by calcifying algae / microbial slime, and layer upon layer gets added with addition growth of those slime layers, growing up through the calcite they trap. It's not a true marble, in other words: it's a limestone.



These limestones with oncolites originated in a large freshwater lake called Lake Flagstaff, approximately 66 to 58 million years ago (Paleocene). The lake was present in northeastern and central Utah. According to Chris Barr, the stone used on the exterior of the Unification Church was quarried at "8,000 feet in elevation, in what is now the Manti-La Sal National Forest in the mountains more than 60 miles south of Salt Lake City."



Some of them have partial void spaces internally, which have since been filled by sparry calcite:


The horizontal layering of the non-spar gunk inside these voids provides a little paleo-horizontal "level" to help reconstruct which way was "up" when these sediments were deposited. (This particular block is on its side in the wall of the church; I've rotated the photo to paleo-up using Photoshop. (That's also where the arrows come from!)

For some perspective on the recent history of the building where these cool rocks are displayed, I'll quote from Chris Barr's soon-to-be-released website: "Changes in the neighborhood, the growing needs of the Mormon community, and the prospect of costly repairs to the walls, led to the end of services in 1975 and the sale of the chapel, which was purchased by the Unification Church in 1977. The Mormons constructed a new, larger chapel in suburban Bethesda - a structure that also provides a visible reference to the temple in Salt Lake City."

Labels: dc, limestone, paleocene, primary structures, utah