Torres del Paine vs. Split Mountain — 1 — Cuernos del Paine
I spent the second half of March in Patagonia with three other geologists. We were in the care of the small guide company Kanaturaleza and spent the first week in Tierra del Fuego and the second in Torres del Paine. This was my second time to Torres del Paine, and this time we were able to hike up into Valle del Francés for spectacular views of the Miocene granite and Cretaceous metasedimentary rocks. We were accompanied by guides Nacho and Sofia from Kanaturaleza.
Cuernos del Paine (Horns of Paine) from Rio Serrano. Miocene granite is capped by dark-brown, folded meta-turbidites of Cretaceous age.
The contact between the light yellow to light gray granite and the dark brown metasedimentary rocks is strikingly sharp from a distance, and strikingly sharp from a closer vantage point. Here is a closer view from Paine Grande camp on Lago Pehoé.
The contact between the granite and its metasedimentary roof is knife-sharp; the metamorphic rocks provide the horns of Cuernos del Paine.
We spent two nights at Camp Francés and spent the intervening day hiking up Valle del Francés to Mirador Británico. The weather was spectacular; light winds most of the time, a high around 65F (18C), and just enough cloud cover to make photos even more spectacular. Here are some sights that we saw on the way up the valley.
Paine Grande (metamorphic rocks) in morning light.
Granite dikes and sills in Cuerno Principal. Note subhorizontal granite dikes in the roof rocks and thin en echelon mafic dike that cuts the granite.
Trace fossils (burrows) in steeply tilted turbidites, Mirador Francés. These beautiful trace fossils are right on the trail at Mirador Francés.
Cuerno Norte (L), Cuerno Principal (R), with Miocene granite overlain by Cretaceous metasedimentary rocks.
Sheeting in granite at Cuerno Norte: another angle showing what appear to be thick sheets in the underlying granite.
Granite roof at Cuerno Norte. Both the granite and overlying metasedimentary rocks are cut by intermediate(?) dikes.
I have posted lots of pictures from our Patagonia trip on my Flickr site, including many more from Torres del Paine.
Being a granite petrologist, getting in to see this stuff up close was a dream for me. But what I found truly striking was just how much the Torres del Paine granite complex resembles the geology at Split Mountain in eastern California (note: there are three Split Mountains in California; this is the one on the crest of the Sierra Nevada between the towns of Lone Pine and Bishop).
Cardinal Peak and the arête to Split Mountain, Sierra Nevada, California. Dark brown Cambrian metasandstones (Campito Formation) sit on Jurassic leucogranite. The greenish summit cap of Cardinal Peak comprises metacarbonates and calc-silicates derived from the Cambrian Poleta Formation.