By Max Cunningham
June 12, 2014
We continued to sample boulders in Valle de Las Morrenas, Valle Talari, where the hostel sits, and several places along Mount Chirripó’s ridgeline.
![Max 7.1](https://sotp.nyc3.cdn.digitaloceanspaces.com/wp-content/uploads/2014/07/Max-7.12-300x200.jpg)
The view from the top of Mount Chirripó is spectacular. Looking out along the ridge I could see huge boulders of granodiorite produced by exfoliation, or the response of rock at the surface to the removal of ice.
![Max 7.2](https://sotp.nyc3.cdn.digitaloceanspaces.com/wp-content/uploads/2014/07/Max-7.2-300x200.jpg)
The actual summit of Chirripó, however, is a very different kind of rock. I believe the peak is composed of a sedimentary rock that was melted and then fused back together as the magma that formed the granodiorite rocks moved toward the surface. This metamorphosed sandstone (meta-sandstone) is extremely hard, and resistant to weathering processes.
In the meta-sandstone near the summit of Mount Chirripó, I discovered glacial striations. These striations occur at 12,513 feet (the summit is 12,529 feet), which is a good 1,000 feet above the moraines in the upper portion of Valle de Las Morrenas.