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

Labels: appalachians, climate change, global warming, new york, rain, sediment, snow

Here's a satellite image of the Caribbean from early Friday morning:



Gustav's still moving northwest through the Caribbean, and set to enter the Gulf of Mexico by about midnight tonight, or early tomorrow morning. As you may have heard, everyone's getting ready for the worst-case scenario. Louisiana governor Bobby Jindal has already declared a state of emergency, and President Bush gave him a similar federal declaration. I'll be watching this one pretty closely over the next few days.

Another phenomenon that's manifesting itself over the coming days and weeks is the melting of the Arctic sea ice pack. As Al Gore noted in his speech the other night, the worst case scenario for melting of this sea ice has the Arctic ocean ice free sometime late in the term of the next president (but that's a worst case scenario). Certainly, the trend over time is towards less and less of the Arctic frozen. I follow the fluctuation of sea ice area on the website The Cryosphere Today (University of Illinois), which provides satellite data, graphs, maps, and animations of the areal extent of polar sea ice. Here, for example, is a graph showing the area of the Arctic Ocean covered by sea ice over the past year:



Last year, of course, it hit a record low, and there's still a few weeks to go before it starts freezing up again (mid-to-late September is the time of the minimum). Open Mind did an excellent post examining the trend here, although the pattern is also observable on this long-term graph from Cryosphere Today. Here's another one, from the National Snow and Ice Data Center at the University of Colorado, that gives a half-century of context to the graph above:

In case DC-area folks didn't hear about it, there's also been some recent flooding in the southwest. (Geoblogospheroids will be well aware of it already, thanks to excellent coverage from Lee Allison at Arizona Geology.) I swam in that canyon this summer, just above the confluence with the Colorado River, and so this caught my attention more than an equivalent story would have about flooding someplace I hadn't been.

In addition to these larger-scale phenomena, there's a more local kind of weather I'm watching too: it's actually started raining in DC, for the first time since I got back on August 1! (A perplexed Achenblog on this odd situation). Time to bust out the umbrella.

Labels: hurricanes, ice, news, rain, snow

Latest gage information from the Potomac River near Little Falls. Looking out my window at Rock Creek this morning, I can see the water is way up, moving fast, and the color of teh tarik.

DC (and many other surrounding municipalities) are under flood warnings this morning as a result. The Washington Post's Capital Weather Gang is impressed by it all.

(Fortunately Saturday's field trip happened to be scheduled between downpours.)

Labels: dc, floods, rain