The previous post in this blog described the world class natural area of White Sands National Monument in southern New Mexico. This post describes another amazing geologic feature only forty miles or so northwest of Albuquerque – the Tierra Amarilla anticline. (It is also called the San Ysidro anticline.)
An anticline is where the earth’s crust has been pushed into an upward pointing fold. It is very much like an upside down “V”. When you add in tens of millions of years of erosion you get an amazing array of formations and exposed rock layers. As a result, the anticline is a great place to wander and explore.
With most of the anticline being on public land and its proximity to Albuquerque, the Bureau of Land Management (BLM) has built several miles of trails on top of the anticline that are very popular with mountain bikers. (Click here for a copy of the BLM map and brochure of the trails.) 60 Hikes within 60 Miles: Albuquerque by Stephen Ausherman describes a very nice hike on these trails.
This is the heart of the anticline and where the bike trails begin. Upward pointing slopes come up from both the left and the right. If the heart of the anticline had not been eroded away, the top of the anticline would have been in front of us.
Although the heart of the anticline is spectacular, the dogs and I prefer to go to the west side of the anticline where there are very few bikers and an old ranch road that is perfect for a quiet walk. (The old ranch road is shown on the BLM map as an equestrian trail.)
We parked the car near here and started walking. If you see a gate like this in backcountry, it’s okay to open it and proceed. Just close it behind you.
Here’s a closer look at the sloping rocks. At one time this layer of rock would have gone up and over the top of the anticline.
As you can see the old dirt road is a great place for a quiet walk.
But you don’t have to stay on the road. You can poke around old ranch remains to see what you can find. You can also clearly see the anticline in the sloping rock layers.
This was a very interesting find just beyond the old ranch remains.
Here’s another good look at the slope of the anticline.
There are bike trails on top of the ridge to our right. We eventually found a path to take us up to the top.
The top of the anticline is predominantly white gypsum rock. There is a large gypsum mine on Native American land a few miles to the east.
From the top you can see the many mineral laden springs that have built travertine domes at the north end of the anticline.
The travertine domes are worth a trip on their own to explore.
The detail on the sides of the travertine domes are well worth the walk.
Returning to our walk along the top of the anticline, you can see the upward sloping layers of rock in front of us. If you look in the distance, you can see the same layers of rock that are still horizontal. They were not pushed up into an anticline. If the far distance you can see an old volcanic plug – Cabezon Peak. That too is worth a special trip.
Here’s a closer look at the upward sloping layers of rock.
With the top of the anticline bring gypsum and with gypsum being quite soluble, there were many sinkholes and fissures along the top of the anticline.
With the trail getting narrower and drop-offs getting steeper it was time to turn around and head back to our car. We did get some more great views on our way back.
If you look closely at this picture, you can see small layers of white gypsum in this almost vertical layer of red rock.
As I hope I have shown in these blog posts, there are many wonderful places to wander. The Tierra Amarilla anticline is one of them.