Monday, May 31, 2010

Dear Diary, - Updated - new update

Latest update: If any of you are thinking of visiting it, the monument is going to be closed beginning June 6 for two months to pave the road. We barely got there in time to see it. Your tires and suspension will be grateful if you visit after this is done. It is just a gravel and dirt road with the typical corrugation to it.

Today my BFF and I took advantage of my having a federal holiday off and drove to Cochiti Pueblo and went hiking at the Kasha-Katuwe Tent Rocks National Monument.
The cone-shaped tent rock formations are the products of volcanic eruptions that occurred 6 to 7 million years ago and left pumice, ash and tuff deposits over 1,000 feet thick. Tremendous explosions from the Jemez volcanic field spewed pyroclasts (rock fragments), while searing hot gases blasted down slopes in an incandescent avalanche called a “pyroclastic flow.” In close inspections of the arroyos, visitors will discover small, rounded, translucent obsidian (volcanic glass) fragments created by rapid cooling. Please leave these fragments for others to enjoy.

Precariously perched on many of the tapering hoodoos are boulder caps that protect the softer pumice and tuff below. Some tents have lost their hard, resistant caprocks and are disintegrating. While fairly uniform in shape, the tent rock formations vary in height from a few feet to 90 feet.

As the result of uniform layering of volcanic material, bands of gray are interspersed with beige and pink-colored rock along the cliff face. Over time, wind and water cut into these deposits, creating canyons and arroyos, scooping holes in the rock, and contouring the ends of small, inward ravines into smooth semi-circles.

Here I am at the beginning of our hike.

And here is BFF bending down to get through a low spot in the slot canyon.

A yucca plant

I would be intrigued to learn what these are.

Update 1: Sue Ellen let me know. "That plant is Apache plume - a southwest plant - grows wild but is also put in southwest landscapes." I recommend clicking on the photo to see more detail on this one.

Cool formations, no?

I wonder what the lighting would be like on one of those spectacular New Mexico sunset evenings.

These are the formations that earned the "tent rock" moniker. Intriguing, no?

We went for the climb to the top, hoping for the spectacular overview, but not long before getting there it seemed evident that the old knees were getting cranky. So we turned around. By the time we got back to the trail head I was clearly starting to overheat, in spite of the water we took with us. So we sat at a picnic table in the shade and enjoyed our picnic lunch: leftover grilled salmon, grapes, strawberries, blackberries, and some sourdough bread. I rehydrated and recaffeinated and we headed home.

A nice thing to do on an incredibly beautiful New Mexico spring day.

Update 2: Gary asked what tuff is.

Tuff (from the Italian "tufo" and pronounced "toof") is a type of rock consisting of consolidated volcanic ash ejected from vents during a volcanic eruption.

Tuff is technically a sedimentary rock formed by the accumulation of volcanic ash plus pumice or scoria. (more below)

Tuff is so closely associated with volcanism that it is usually discussed along with the truly igneous rocks around it. Tuff tends to form when erupting lavas are stiff and high in silica, which holds the volcanic gases in bubbles rather than letting it escape. The brittle lava is readily shattered into jagged pieces, collectively called tephra (TEFF-ra) or volcanic ash. Fallen tephra may be reworked by rainfall and streams. Tuff is a rock of great variety and tells the geologist a lot about conditions during the eruptions that gave birth to it.

If tuff beds are thick enough or hot enough, they can consolidate into a fairly strong rock. The city of Rome's buildings, both ancient and modern, are commonly made of tuff blocks from the local bedrock. In other places, tuff may be fragile and must be carefully compacted before buildings can be constructed on it. Residential and suburban buildings that short-change this step remain prone to landslides and washouts, whether from heavy rainfall or from the inevitable quakes, like that which struck San Salvador in Central America on 13 January 2001. There many buildings on the local tierra blanca tuff collapsed.

Close-up of the canyon wall showing the varieties
of rock contained in the sedimentary layers.

--the BB


Fran said...


it's margaret said...


Are the holes old volcanic vents or animal dwelling of some sort?

And, tents??!!!!

Paul said...

Conical tents, like tipis.

The pockets in the rocks are from chunks of harder rock, presumably scattered in volcanic explosions, that settle in the sedimentary rocks and, with erosion, fall out, leaving pock marks, so to speak. If those are the holes you are wondering about.

susankay said...

I love Tent Rocks -- fwiw: the obsidian droplets are called apache tears

Padre Mickey said...

I wanted to see the photo of you at the end of the hike.

Paul said...

Miguelito, what a malicious thought! You can take the first photo, drench it with sweat, redden it considerably, and give it a hang-dog look. I know your imagine is up to this.

Michal Anne said...

how cool! I thought I might go by tent rocks on the way home from Christ in the Desert today, but ended up in Santa Fe instead, looking at singing bowls. But tent rocks is definitely on our "must see" list.