Integrative Natural History of Old Ore Road, Part 10: Relex Redux | Big Bend National Park, Texas, USA
Looking northeastward at the western face of the Sierra del Carmen. This was taken in the same locale as the Part 9 photo, which is to say we're about 5.5 road mi / 8.9 road km north of the Carlota Tinaja stop documented in Part 7 and Part 8. That equates to being approximately 12.4 road mi / 20.0 road km north of the intersection of Old Ore Road and Park Road 12. How about that for a lot of geolocation?
This is a closer, tighter view of one section of the imposing fault scarp of the Alto Relex horst. To review the Laramide-Orogeny and Basin-and-Range tectonics that went into making this impressive feature, see the Part 9 description.
The rock unit we're gazing at is the cliff-forming Santa Elena Limestone, the Lower Cretaceous formation also so dramatically displayed in the park's Santa Elena and Boquillas Canyons.
When it's near or at the Earth's surface, the Santa Elena Limestone often develops deep vertical joints (fractures where no sizeable displacement has occurred) and karst (solution features created by acidic precipitation and ground water). Some karst features visible here include caves and widened joints.
As jointed sections of the Santa Elena cliff face continue to weather, they can turn into freestanding hoodoos, which often assume a spire- or chimneylike shape. The process of hoodooification has apparently not progressed as far at Alto Relex as it has at Boquillas Canyon, but there are a few examples of weird and funky forms emerging from the bedrock. Can you find any of them in this image?
To see the other photos and descriptions in this set, visit my my Integrative Natural History of Old Ore Road album.
Integrative Natural History of Old Ore Road, Part 10: Relex Redux | Big Bend National Park, Texas, USA
Looking northeastward at the western face of the Sierra del Carmen. This was taken in the same locale as the Part 9 photo, which is to say we're about 5.5 road mi / 8.9 road km north of the Carlota Tinaja stop documented in Part 7 and Part 8. That equates to being approximately 12.4 road mi / 20.0 road km north of the intersection of Old Ore Road and Park Road 12. How about that for a lot of geolocation?
This is a closer, tighter view of one section of the imposing fault scarp of the Alto Relex horst. To review the Laramide-Orogeny and Basin-and-Range tectonics that went into making this impressive feature, see the Part 9 description.
The rock unit we're gazing at is the cliff-forming Santa Elena Limestone, the Lower Cretaceous formation also so dramatically displayed in the park's Santa Elena and Boquillas Canyons.
When it's near or at the Earth's surface, the Santa Elena Limestone often develops deep vertical joints (fractures where no sizeable displacement has occurred) and karst (solution features created by acidic precipitation and ground water). Some karst features visible here include caves and widened joints.
As jointed sections of the Santa Elena cliff face continue to weather, they can turn into freestanding hoodoos, which often assume a spire- or chimneylike shape. The process of hoodooification has apparently not progressed as far at Alto Relex as it has at Boquillas Canyon, but there are a few examples of weird and funky forms emerging from the bedrock. Can you find any of them in this image?
To see the other photos and descriptions in this set, visit my my Integrative Natural History of Old Ore Road album.