Kaibab Exposure above Ash Creek, Toquerville
 
 Hikers drove up the Ash Creek road above Toquerville, to the east, in S35 & 36 
T40S R13W, to the basin of the Ash Creek, some 2-3 miles along a gravel road. 
This road bifurcates in two, one road leading down to the Laverkin Creek valley 
to the south. We proceeded to the north, to view the Kaibab, and overlying 
Triassic, just to the north. The whole valley- trending N-S- suggests large 
faulting- and indeed the UTAH geological map shows two N-S fault splays here. 
 The Kaibab limestone juts (NW) into the air in the form of a hogback (wrong 
terminoology for a limey sediment) pointing to the Pine Valley Mts. It also 
trends roughly in the same orientation- NE-SW- as do the nearby anticlines and 
P.V.Mtns., indicating that it was shoved upward by the Laramide and later 
intrusion (21 My. years age). This anomaly will be investigated, for 
incorporation into a scheme for understanding the Laramide and later stresses, 
because the orientation is different from most others. Generally the Pacific 
plate shoved eastward to NE-ward, on this SW side of the Colorado Plateau (all 
the way to the Rocky Mts). But in this case, the direction of stress was from 
the NW- yielding a NE-SW line of uplift (compressional effect).  This weakness 
fom the 70 my. year old compressional stress in the Laramide (Pacific plate 
subduction) was preserved to later influence the uplift of the P.V. Mts. and 
then bringing erosion and subsurface water to the SE- yielding such things as 
the Silver Reef deposit and granite-like boulders (quartz monzonites) to fall 
around the town of Leeds.
 The Kaibab was a result of a late stage inland sea in the Permian, yielding 
limestones, which are fairly pure in this outcrop compared to that near 
Flagstaff- where they are sandy, with identifying brachiopods and crinoids. This 
shows that the sea came from the west and became shallower to the east or SE. 
The Kaibab is usually the latest  of the Permian in this area, and is overlain 
by the variable Moenkopi (Triassic)- which may be sandy, evaporitic, shaly or 
marine, indicating that it was transitional (continental to marine near shore). 
The Moenkopi occurred as the main stratigraphy for the hike in the Quail Creek 
anticline (Virgin), where it was considerably thicker than where I have seen it 
near Flagstaff.
You may want to ask the question about the change of atmosphere and groundwater 
acidity in mid-Permian (1st redbed is in the Supai- mid-Permian, locally), which 
I introduced last week, since the Kaibab (Upper Permian) occurs as a dark 
sediment deposit, and produces oil to the east of here in Utah. If the 
atmosphere were changing to an increasing oxygen fraction, and the groundwater 
ws becoming more alkaliine as a result, why does the Kaibab- which is out of 
this trend- now occur, this late in the Permian (as a denial of what has 
occurred before in the mid-Permian? Tentatively, this shows the slow rate of 
change of the atmosphere-ground water system in the earth. The deeper Supai 
Group of sediments are the first of the Permian redbeds, and they are overlain 
by the Coconino Sandstones- another fossil dune sequence in the Permian (meaning 
that similar to the present Sahara desert, not a coastal dune field), and 
finally the Kaibab. The later thin limestones, in the overlying Trm (Moenave) 
and Km (middle), represent oscillations in the CO2 to Oxygen transition, 
overwhelmed by massive silicate sediments in most of the Mesozoic. We will study 
this, when we get further afield, in surrounding regions. For now, there were 
thin layers of limestone during the dinosaur times, but the overwhelming 
sediments are continental throughout the Mesozoic, until the Cretaceous Period- 
that is to say, they are mainly stream deposits (sandstones, shales, and 
siltstones) and windformed dunes.
 Sedimentation found after the  Permian is mainly silicates, as compared to the 
limestones of the Paleozoic.
 Above the Trm, was the Chinle- still in the Triassic, Trc- which contains the 
Shinarump member, the carrier of the volcanic ash-influenced petrified wood. 
This was explored in the road crossing to the east of the Kaibab hogback, where 
it easily erodes and leaves its harder chert and opalized wood. Although the 
volcanic ash is obscure here, it is dominant in the Navajo reservation- as a 
grey to purple shale or clay. I have found  one upright tree trunk going deeper 
than I could exhume, indicating that the trees were standing when buried (in 
this case, possibly by a flood). No fossilized wood was found to the east of the 
Kaibab cliffs, but an abundance of gypsum was found in the east tributary of the 
Ash Creek- occasionally as gypsum roses- pink in color. Some os these were 
display grade, along with abundant selenite. Finally, in the east tributary, the 
Kaibab, Pk, was found in the creek bottom, indicating that the fault had been 
crossed (which yielded a 1000 foot higher elevation just to the north on the 
west tributary. The fault could not be seen in the creek, which yielded a 
saddle- viewing from the north, but to the east the Kaibab could be seen on the 
ridge line- first as a bed tilted up to the west, then level, then up to the 
east  in the creek bottom.
 The fault trace could be seen just below the cliff face to the west as a 
contact with much younger basalt rubble (Pleistocene?). The basalt comes from 
the east, and is disrupted by the Hurricane fault- yielding a tentative age for 
the fault (<2my.?). Probably, the Hurricane fault we are investigating and 
noticing to be active moved many times in the past, but not as marked as can be 
seen now.
 There are evidently several splays of the Hurricane fault in this location, as 
evidenced by several saddles along the gravel road to the east. Upon trekking 
this main tributary to the east, seeps and springs are numerous (after the 
recent rain), and the water is not as hard as would be expected (To Drink) for 
1200 ppm saturated CaSO4 water. However, the Kaibab is conformable with the 
overlying Moenkopi, and it is expected that the main faults are not along this 
tributary, but further to the east above the creek.
 The question to ask here is: Since the Kaibab hogback is east of one large 
splay of the Hurrican fault (we'll call it Fh), how is it that the Kaibab juts 
up to the west? One would think that a large uplift would offset the pre-
existing anticlinal dip, and cause it to be moderated, especially being dragged 
upward on the east side. This effect is displayed in the creek to the east, 
where the beds dip upward to the east- just what is expected for a normal 
faulted uplift to the east (the Zion uplift, displayed in the Zion Park), but 
this is not the case for the Pk to the west. There is some strong interference 
from the 21 my. P.V. Mtn laccolith, causing the Kaibab uplift to be accentuated. 
We will study this further, with a consideration that the wrong dip may have 
been caused by the Laccolith (and not by the 70 my. Laramide compresssion).
 Questions to pursue on future hikes include:
1. Can the anticlines and Kaibab uplift seen on this hike have been caused by 
the Pine Valley Mtn. intrusion, and not by the Laramide subduction and 
compression?
2. Why are the saddles in this valley not at the expected large fault, but along 
minor expressions?
3. What is the age of the oldest of the basaltic extrusions? In general terms, 
extrusions happened after the dogleg in the Hawaaiian- Emporer Seamount chain, 
after 41 my. age, as noticed in central AZ. I have found some volcanics there of 
about the age 25-30 my. The Extensional dynamics started in the west after 41 
my.time, and the compressional dynamics had expired before then. Harold L. 
Overton