Untitled Document

 

CHA
GEOLOGY WALK, NOVEMBER 9, 2002

(Initial
orientation; walk across Soza Mesa — Quiburis Formation — to the edge of the
canyon slopes; head down

..

Below
left: view of the Canyon where we are headed; right: not far downslope, we reach
the Willow Canyon formation and examine some of these distinctive 100 MYa rocks;

Below
left: one characteristic form of Willow Canyon Conglomerate; below right: Willow
Canyon formation is visible across the Canyon — the reddish formation — where
the Hot Springs Canyon Thrust Fault has forced it above and over the younger Cascabel
Formation (65 Mya):

Below
left: a large “Isoclonic” fold created by the Thrust-faulting: the reddish
formation has swept over and encapsulates the lighter-colored Cascabel formation.
Above them both is a capping layer of much younger Galiuro Volcanics (30-25 Mya).
Below right: looking further downstream, we could see across the canyon where
the Galiuro volcanics lies atop the Willow Canyon formation in an almost straight
line:

[Note: here we will need some help from Mick Meader to get a brief
description and maybe his photo-and-diagram combination showing how this fold
works)

Below
Left: Approaching the lip leading into the Canyon, looking directly toward the
Zig-Zag bend; below right, the reddish Willow Formation where it has thrust over
the lighter-colored Cascabel Formation.

Below
left: we hike down the steep slopes into the bottom of Hot Springs Canyon. Below
right: Mick Meader gives us some further information on the nature of the Hot
Springs Canyon Thrust Fault (which at this point lies directly behind and above
him:

Below
left: Bob Scarborough rests against the Cascabel Formation Conglomerate found
in the streambed; right: he points out the position of the fault boundary — Cascabel
Conglomerate below, Willow Canyon Mudstone and Sandstone (?) above:

Below
left: a closeup of the fault juncture; below right: we head on downstream, looking
at further folding in the Willow Canyon formation in this part of the canyon (above
The Narrows, which can be seen in the background):

Below
left: a final consultation of the group before we leave the Canyon; below right:
a view of the lower part of it above the yellow cliffs as we depart:

 

 

 

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