Redwall Limestone

From a hiker’s perspective, the Redwall Limestone is the most important formation within the Grand Canyon. It forms massive, impassable cliffs that soar as high as 800 feet, and the routes that trails can follow through it are few and far between. If you are an adventurous and courageous hiker and find and publish a new route through the Redwall, your fame as a Grand Canyon hiker is assured.

The Redwall marks a major ecological boundary in the park. When you get below the Redwall, you are truly in the desert. Vegetation is sparse. Looking down on the Tonto Platform from above you see little more than a gray sea of scattered blackbrush. Snow is rare in the winter and the summer is brutally hot.

At the top of the Redwall you will see at least some scattered cedar trees, and trees become more and more prevalent as you continue up to the rim. Snow in winter commonly reaches down as far as the top of the Redwall, and though it is hot in the summer you are in striking distance of the rim. If you venture to hike below the Redwall, you better be prepared and know what you are doing, or you may become one of the dozen or so hikers that die in the canyon each year.

Looking down on the Redwall from above, as we are doing here from the South Kaibab Trail, you see an unrelenting, menacing barrier of reddish cliffs as far as you can see. The wall, as seen here, typically forms a series of curving alcoves strung between ridges sloping down from far above.  You wonder just where you will find a route through it, but routes have been formed by fault lines, landslides, erosion, and here and there by the application of good old fashioned dynamite.

When you hike down from the rim and reach the top of the Redwall, you are just about half way down from the rim to the Colorado River. If you are a good, fit hiker, a trip down to the top of the Redwall and back up makes for a fine day hike. Views from the top of the Redwall cliffs, such as here on the Tanner Trail, are spectacular.

The top of the Redwall also makes for a fine place to camp and break up the long hike out of the canyon from the river to the rim. Any campsite on top of the Redwall, however, will be a dry camp without water, so you will either have to haul water up with you from below, or, as I like to do, carry extra water with you down from the rim and cache it for use on the way out.

Looking up at the Redwall from near its base, such as here along the South Bass Trail, is even more intimidating. If only you could soar like one of the canyon’s ravens, catch an updraft, and just flit on up to the top.

When you spend time hiking in the inner canyon, most likely somewhere on the Tonto Trail, the Redwall becomes the upper boundary of your world, separating the open expanses surrounding you on the Tonto Platform from the outside world above and beyond. Much of the time the Redwall will block the view of anything above it, but you do get glimpses back up to the rim here and there, such as here along the Tonto Trail near Monument Creek.

Redwall really is a misnomer – the color of Redwall Limestone is actually gray. The red color comes from minerals, mostly iron, carried in rainwater seeping down from the Supai and Hermit Shale formations directly above the Redwall. In places, such as here along the South Kaibab Trail, where the Supai overlaying the Redwall has been completely eroded away, the reddish patina disappears in time and the Redwall reverts to its natural grayish color.

 Climb to the top of any small, isolated hill on the Tonto Platform (as I love to do to shoot panoramas) and you’ll see what you see here: a pile of Redwall boulders, left over from some long-ago landslide, eroding much more slowly than the soft Bright Angel Shale around it and forming the hill. Notice that all traces of red are long gone, and that the surface is pockmarked. Redwall boulders are nasty. Sit on them and, unless you are very careful, the sharp edges formed by the pockmarks will rip your pants or shorts to shreds. But sittable rocks on the Tonto are scarce, so often they have to make do.

I could not end my discussion of the Redwall without calling out this spot along the Bright Angel Trail. The trail follows a gap in the Redwall formed by the Bright Angel Fault ripping it apart. You come to this spot about half way down Jacob’s Ladder, the set of switchbacks that the trail follows down through the gap. You stand at the edge of an alcove just a few yards away from a massive wall of Redwall wrapping around and soaring above and below you. Is is a magical place to me, and was even more so the day I shot this panorama in the middle of a snowstorm, with wet, heavy snow clinging to tiny ledges in the rock face, forming delicate patterns.

To read more detailed geological information about the Redwall Limestone, visit the United States Geological Service page for the Redwall Limestone.