[Rockhounds] Mosul Dam

[Gary Brown]

I doubt if it was Pactola.  That's in the core section of the mid-northern
hills. The Spearfish fm surrounds the hills (except for a couple of weird
pockets).

GcB

> -----Original Message-----
> From: rockhounds-bounces at lists.drizzle.com 
> [mailto:rockhounds-bounces at lists.drizzle.com] On Behalf Of 
> Andrew Turner
> Sent: Tuesday, October 30, 2007 1:20 PM
> To: rockhounds at lists.drizzle.com
> Subject: RE: [Rockhounds] Mosul Dam
> 
> I'm pretty sure you are referring to the dam at Pactola 
> Reservoir which I believe is built into part of the Spearfish 
> Formation.  One of the people I work with used to do work up 
> there and knows quite a bit about this dam and some of the 
> issues (including political) involved with it's design and 
> construction.  I've been there several times (took a field 
> geology course and lived there a summer working at Jewel Cave 
> Nat'l Monument).  In all fairness, if a dam needed to be 
> built in that area, almost all of the formations would have 
> been poor choices (even the granite which is very friable and 
> loaded with shear planes, pegmatite veins, joint sets, etc. 
> and isn't found much in the area near Pactola).
> 
> Andrew Turner
> Victorville, CA USA