Papago Buttes, Phoenix Arizona - picture rich.

[1dave]

@edmost and I got into this subject in "Pre-Phoenix."
My grandson Adam McMBarron was just transferred there by State Farm, and I'm trying to get him interested in the buttes, AND those ODD CAVES WITH THE HANGING TONGUES!



Google Earth just made a new brief pass on McDowell Road from 52nd St to 64th St in January of 2018 so I was able to snag some new images.

First, an overall view.





Driving east and looking at Barnes Butte on the left. (McDowell Butte is on the right.)





Arizona National Guard controls access.

[1dave]

McDowell Butte
That morning the McDowell side facing the road was mostly in shadow.



Now that summer has arrived and shining on the other side I would love to have some new photos of here.



Do you see what I see?


One of my favorite views!


BUT they are ALL like this!

[1dave]

Jul 29, 2018 13:09:45 GMT -7 @edmost said:

Thanks Dave

ya save me a trip
even though it only mile or two down that rocky road
my car over heat
no refer
and it hot & humid about

I did make it Burton Barr yesterday
and did some more studying
on the Lost City of Cibola

hard to follow Peterson
when he indicates that
a river, canal, Hohokam settlement
were on the east side of the buttes

but he does mention Indian Bend Wash
which present possibilities

tell your grand son
welcome to Phoenix
heck of time to be here

I almost worked for State Farm
at the 52nd St facility
they had there major print operations there...

[1dave]

Geologic Details

There are 8 buttes, the base is 250 million year old granite. All subsequent layers were swept away prior to the now top two layers of landslide debris.

I suggested the landslides came from the Carefree area north of Phoenix, but SEAN W. CAMPBELL*
Department of Geography Arizona State University Tempe, AZ states they came from South Mountain.
onlinelibrary.wiley.com/doi/pdf/10.1002/%28SICI%291096-9837%28199903%2924%3A3%3C271%3A%3AAID-ESP969%3E3.0.CO%3B2-T

Whatever the original location, the sharp edges of the pieces testify they didn't travel far.

An excellent presentation by Callan Bentley (an assistant professor of geology at Northern Virginia Community College) is at:
blogs.agu.org/mountainbeltway/2018/01/11/landslide-breccias-papago-park/

Does this look like sandstone to you?

Tafoni are small cave-like features found in granular rock such as sandstone, granite, and sandy-limestone with rounded entrances and smooth concave walls, often connected, adjacent, and/or networked. Wikipedia

[1dave]

South Mountain Landslides?

South Mountain Geology map

South Mountain Geology

Yes, I'll buy it! The rocks didn't travel far.

[1dave]

Aug 1, 2018 9:15:01 GMT -7 @edmost said:

Another hypothesis to explain the unique features of the buttes

Especially the sediment encrusted clastic material
So strange

The buttes looks like a Biblical proportion mudflow
that just froze in time/
And the remaining buttes are the last weathered remnants.

Catastrophic mudflow, landslide, rock & roll are all intuitive.
But that may be an illusion
Just as the earth appears to be a sphere but is actually flat
Easy to be deceived

So the hypothesis states that
The South Mountain Metamorphic Kinemathic Complex
up lifted the sediment fill of the Valley basin.

The buttes are the valley sediment exposed.
Weathered & oxidized.,
This deep sediment was up lifted by a plutonic thrust during the
Kinemathic Complex.

No mudslide or rocknroll needed.
Just deep earth exposure

But No !

There is a problem with the ingenious theory
The sediment fill of the valley is not filled with clastics.

Amazing how relatively rocks free the soil in the Valley is.
Well at least for many feet of digging.

This photo is of an archeology dig that makes my point to an extent.



The excavation was at a Hohokam site 2 miles west of the Papago. The dig was at least 8 feet deep.

This band of exposed rocks are at least 4 feet down from the surface.
No clastics!

Just a band of stones in rich soil.
Which is why I took the picture.
Another strange phenomena.

But my hypothesis may still be saved
This plutonic thrust brought the material up
from deep in the Valley basin
Deep!
Hundreds of feet deep.
In those depths clastics may reside
So that is what is exposed in the buttes/


Yet you may ask:
‘O’K mohs-- where do those clastics come from'?

Well obviously there was catastrophic
mudflow & mountain disintegration
rock n roll event that occurred eons
previously...