Key takeaways
- Water has sawed a narrow gorge straight through the upturned strata of the crater rim.
- A short stop between lunch and the afternoon at the footprints.
- Nowhere else on the tour shows the tilted beds as plainly in so small a space.
- The Devil’s Throat, which is applied to narrow gorges across the Spanish-speaking world.
What it is
A narrow gorge cut through the upturned rock on the floor and edge of the Maragua formation, deep and steep-sided, with the strata exposed on both walls.
The name, Devil’s Throat, is attached to narrow gorges and waterfalls across the Spanish-speaking world, most famously at Iguazu. This one is smaller, quieter and more instructive.
It sits within the day between lunch on the crater floor and the afternoon at the footprints, and takes about half an hour.
How water cuts through tilted rock
A river takes the easiest line it can find, and in folded country the easiest line is usually along a soft layer rather than across a hard one. Where a stream is forced across the grain of the rock instead, it has to saw.
The result is a slot: narrow, because the water is cutting down far faster than the sides are weathering back, and steep-sided, because the rock is hard enough to stand.
That is what you are looking at. A gorge like this is evidence of a watercourse that was there before the shape around it finished forming, and that kept its line while the landscape changed.
There is a name for a river that keeps its course while the land rises across it: an antecedent stream, one that was there first and cut down as fast as the rock came up. Whether every gorge of this kind qualifies is a question for a geologist standing in it, and it is a good question to put to the guide.
The narrow cut through near-vertical beds of red and grey rock
Reading the walls
The two walls are cross-sections. You can see the individual beds, their thickness, their colour, and the angle they now stand at, which around here is close to vertical.
Each band is a period of deposition: a season, a flood, a change in what the water was carrying. Read from one side of the gorge to the other, they are a sequence in time laid out sideways.
It is the same story as the footprints and the rings, told in the smallest available space, and it is much easier to grasp here than from the rim.
What the rock is
Sandstones and mudstones, laid down in shallow water and on flood plains, in reds, ochres, greys and whites. The colours come from iron in different states of oxidation, which is why the reds are so emphatic.
Hardness varies bed by bed, which is the whole reason the landscape looks the way it does: the hard beds stand up as ridges and the soft ones become valleys and floors.
In the gorge you can see both kinds within a few metres of one another, weathering at visibly different rates.
The iron is worth a moment. Red rock means iron that was exposed to oxygen as the sediment was laid down, in air or in shallow well-aerated water. Grey and green beds in the same sequence mean the opposite: iron that stayed reduced, buried in oxygen-poor mud. The colours are a record of the environment, not decoration.
30 min
Time the tour spends at the gorge, between lunch on the crater floor and the afternoon at the footprints. It is the clearest short view of the geology on the day.
Walking there
It is a short walk rather than a hike, and part of it is a viewpoint. The going is uneven and there are drops, so it wants ordinary care rather than equipment.
Stay where the guide indicates. The edges are rock rather than fenced platform, and this is not a site that has been engineered for visitors.
Half an hour is enough to see it properly and to take the photographs, and the schedule allows that rather than rushing it.
Photographing it
Narrow gorges are difficult: the contrast between the lit rim and the shaded floor is beyond what most cameras handle in a single frame, and the middle of the day is the worst time for it.
Expose for the rock rather than the sky, and if the sky is going to be blown out anyway, compose to keep it out of the frame. The walls are the subject.
A person in the shot solves the scale problem, which is otherwise impossible to convey.
One more suggestion, which applies to the whole day rather than only here: take at least one photograph without trying to make it beautiful. A plain, well-lit record of the wall, with the beds legible and something in it for scale, will teach you more when you look at it six months later than any number of dramatic compositions.
What else is nearby
The crater floor itself, with fields and houses, and the rings of upturned rock standing around it. The footprints, which the tour goes to next. And the road out, which climbs to give a last view back over the whole structure.
The gorge is a small part of a large formation and it is the part that explains the rest, which is why it is worth the half hour rather than being an add-on.
It is also the quietest stop of the day.
It is also the last stop before the footprints, which makes it a useful pause. Whatever the guide has explained about folded strata on the drive in becomes concrete in the gorge, and the tracks in the afternoon then land as a conclusion rather than as a separate curiosity.
