Tuesday, March 14, 2017

The Roan Cliffs Again, This Time with Some Contacts

After seeing Ron Schott's awesome and enlightening GigaPan of the Roan Cliffs, I decided I had to mark some contacts on the photos from my last post (and partly because what I said or implied about the formations were a little off). To deduce the location of these contacts, I extrapolated from this USGS preliminary geologic map, using the USGS TNM 2.0 Viewer and Google Earth.
In the first photo, it's still a toss-up, imo, as to whether the Tertiary Uinta Formation (Tu) can be seen—but if so, it's way up at the top of the cliff. Most or all of the cliff and most of the slope is underlain by the Tertiary Green River Formation (Tg). Aaaaand maybe there's a bit of the Tertiary Wasatch Formation (Tw) at the bottom of the photo.
In the second photo, there is (probably) just a tiny bit of the lower part of the Uinta Formation (Tu) above the cliffy area, and the reddish-brown foreground slopes are underlain by the Wasatch Formation (Tw). The rest, cliff and slope, consists of Green River Formation (Tg).

Thursday, March 9, 2017

From the Road: Bedding and Talus in the Roan Cliffs of Colorado

Getting back to my October-November road trip (last seen here), I stopped to get some fuel in Parachute, CO, on what was Day 7 of the trip, and I ended up taking a few photos (surprise!), partly thinking that the cliffs show good examples of bedding, and also because I was becoming fascinated by the exceptional talus slopes coming off the cliffs. The first photo is a cliff at a round nose sticking out from Mt. Callahan. The second photo is of a cliff at the southern end of a nose known as Allen Point, a long skinny ridge running about 1.5 miles south of a broader, arcuate area also called Allen Point.
When I investigated this area after my trip was over, I was surprised to find that these cliffs are part of the Roan Cliffs: while still enroute, I thought I was driving along the Book Cliffs. The Roan Cliffs are the cliffs that break south off of the broad Roan Plateau, a large plateau area that extends from Rifle, CO, to at least somewhere north of Grand Junction, possibly bounded on the west by Roan Creek. The Roan Cliffs, however, at least as shown here, encircle a broader area extending westward from Rifle, CO, to the mountains just east of the Wasatch in Utah.

The Roan Cliffs are capped by the Eocene Uintah Formation (which we may or may not see in these photos), and slopes below the uppermost cap are composed of the Eocene Green River Formation. Some of the lower, reddish slopes in the area are underlain by the Paleocene to Eocene Wasatch Formation. You can read a little more about the geology of the area in this USGS Bulletin.

The Roan Cliffs stratigraphically overlie the Book Cliffs, which we'll see later. I'm not sure how I mistook the cliffs of the Uintah Formation and upper Green River Formation for cliffs of the Cretaceous Mesaverde Group, or slopes of the Green River Formation for the usually easy-to-spot Cretaceous Mancos Shale. I can only plead that geology at 70+ mph isn't always spot-on.

Tuesday, March 7, 2017

Tales of the Mojave: A Bit About Northern Exploration Company

I planned to have this descriptive section as part of the last post—the one about being packed and ready to leave town—but this "little bit" grew and grew, and eventually it had to find its own home. I've written lots of little pieces like this; many of these could be hyperlinked from several main posts. This one might most properly go near the beginning of a Tales of the Mojave book.


Northern Exploration Company (NEC), a famous former international mining and minerals exploration company, had seven exploration offices when I began working there as part of a small horde of young or “junior” geologists in NEC’s Western District. Some of us were temporary summer hands (and many of us, like me started that way); many of us were on year-to-year contracts (me!); and a very few of us ended up with permanent positions in the company. There were three or four permanent geos leading the horde when I began working there; that permanent cadre had expanded to maybe six by the time I left.

When not out in the field, we worked out of one of several office-warehouse complexes scattered here and there in Reno and Sparks.[1] The complexes seemed to have been slapdashed together and often had a few problems; for example, the typical southwest-desert–inspired flat roofs were prone to leak during storms or snow-melt. Our complex—and a nearby complex leased by another, also famous former mining company—was near the Truckee River and so occasionally flooded. The large windows of the office half of our complex faced south across a largely undeveloped area of the Truckee Meadows; these windows caused overheating, especially in winter when the low sun provided unplanned for solar energy. Nonetheless, we had a good setup that included a smallish warehouse in the back with shelves for field supplies, tables for core logging, and rock saws and grinding wheels for cutting and polishing hand samples.

The Western District of NEC was a decidedly renegade district, though at the time renegade attitudes were fairly common within exploration groups based out of Reno.[2] Geologists aren’t ordinarily known for their adherence to rules, and they are especially not known for following pointless and questionable rules sent down from above—an above that was usually either outside the country or east of the Mississippi, the latter being nearly the same thing as a foreign country to those born and bred in The West.

We can argue nearly forever about where The West begins or ends. The Mississippi River clearly constitutes one viable boundary for defining what is east and what is west. The hundredth meridian has also been used as the boundary between east and west; for example, in 1843, Thomas Farnham said lands between the 100th meridian and the Rockies were “usually called the Great American Desert” (Stegner, 1954). Later, Thomas Durant held a “100th Meridian Excursion” when Union Pacific crews passed the 100th meridian in 1866, a goal set by Congress. A little later, John Wesley Powell, writing for the USGS in 1879, recognized the 100th meridian as a line roughly defining the eastern boundary of his “Arid Region,” an area that generally receives less than 20 inches of rainfall per year and encompasses most of the west (by any definition). I think one could also use the Great Continental Divide as the boundary between east and west: All drainages east of the divide would drain to the Gulf of Mexico or the Atlantic. All drainages west of the divide would drain to the Pacific.
Google Earth image with yellow line marking part of the 100th meridian. The meridian cuts several states in two and roughly separates a greener area in the east from a notably browner area in the west.
I usually maintain that the true west, “The West” as I capitalized above, begins at the eastern edge of the Front Range of Colorado. Denver is not inside The West by this definition. (Neither is Boulder, for that matter.)

As mentioned in our main text above, geologists within the exploration offices of the west (however we define west) were often fractious and rebellious, and they were unlikely to listen to anyone from Chicago, say, some muckety-muck who might be sporting a fancy three-piece suit and polished black shoes. (There are numerous stories revolving around entertaining such VIPs.) Denver’s offices were often a little spiffier than those in Reno, perhaps having been influenced somewhat by the fancier petroleum offices in the area. Also, some Denver offices acted as headquarters for the minerals explorations groups of larger companies, and some *were* the headquarters for smaller companies. Consequently, geologists who had the misfortune to be based in Denver often ended up being a little more stilted, a little less rebellious, a little more formal: they were ever-so-noticeably more well-behaved when it came down to orders from above, and they were a little more likely to look at you askance if you decided that a rock-throwing contest was in order before the sampling program began in earnest. (A few were definite leaders as far as renegade actions go—here I’m particularly thinking of some unnamed few during my later years at Former Mining Company. Most, though—well, many—tried hard to keep up.)

The Kmart of Exploration

Our Hughes 500-D in 1978.
The Western District of NEC came to be known, at least to a select few, as “The Kmart of Exploration.” This appellation had been assigned to NEC by a summer hire[3] —Dan, the guy with the Frisbee dog, a black and white Aussie of one variety or another—during the uranium summer of 1979. He said he came up with the epithet after being involved in procuring supplies and provisions for the field largely at Kmart. I thought the nickname—seemingly indicating that the company was cheap—was overstated; after all, each uranium camp[4] had a trailer with space for a full kitchen; an office with drafting area, map storage cabinet, and beaucoup supplies; a camp cook; canvas tents with room for two field hands in each tent; a couple of 1978 4WD pickup trucks, brand new during the uranium summer of 1978; and a Hughes 500-D helicopter equipped with radiometric instruments capable of detecting radiation and breaking it down into the three major source elements, potassium (K), thorium (Th), and uranium (U). I thought our camps and equipment were pretty plush, especially when compared to the archaeological camps my husband frequented.

Much to the head honcho's dismay, "Kmart of Exploration" stuck. Perhaps it was partly our field schedule that made the name stick. We worked eleven and three, drive-on-your-own-time. That schedule meant eleven days in the field, three days off, with the driving time between home and field (and vice versa) being on our own time, not on paid-for company time. Perhaps the name stuck because we were encouraged, if not required, to camp out rather than stay in motels.

Camping supposedly saved gas, time, and money because we didn’t have to drive in to town every morning and evening and didn’t have to spend money on motel rooms. We also bought groceries instead of eating in restaurants, resulting in a lowered food expense. So we typically lived outdoors—in the dirt and weather of whatever area we were working in—for two to four nights; then we were into town for one night to get a shower, to sleep in a cool, air-conditioned motel room, to gas up, to stock up on fresh food, and—most importantly in the Mojave—to stock up on water and ice. Then, back into camp mode we went. I thought there were some flaws to the party line about camping, although I never did an actual cost-benefit analysis. For one thing, those of us who didn't have a permanent camp located somewhere near running water in the higher and cooler reaches of eastern Nevada (a certain lucky few that I was rarely part of) spent a certain amount of time setting up camp every evening. After getting our new camp in order, we made dinner and cleaned up. Then, nighty-night. After waking up in the morning, we tore everything down and repacked the back of the truck. With all the unpacking at night and repacking in the morning, we often ended up rearranging boxes of sample bags twice a day. Because we prepped our own camp and food daily, we were essentially working twelve to fourteen-hour days, rather than ten, with little time to rest or recoup in the evening before falling asleep (on cots or on the ground). Ten-hour field days were de rigueur at NEC. That meant we'd quit camp at 7:00 am, say, with breakfast and camp tear-down already complete, then work in the field until 5:00 pm. Then we'd finally get on to camp setup and dinner making after that. When someone else was cooking your meals and when there was running water available for cooling off and even showers, as in the uranium and moly camps, the hours were okay—long, but feasible.

In the Mojave, they were hell.

To be continued...


[1] These complexes were often called "geo-ghettos" back then—although that term would probably not be politically correct now—often because they weren't built all that well in some respects, and also because they seemed to house a lot of geological groups.

[2] We cultivated—or were known for—a semi-outlaw attitude and everyday defiance that was deliberately exacerbated by the temperament of the head honcho in Reno.

[3] We didn’t call our summer employees “temps” until a good number of us moved to Forminco, where "temp" was already in use.

[4] For more about the uranium camps, see this series about the Caliente camp of the first uranium summer (that's what we called them: the first uranium summer, and the second uranium summer).

A Reference

Stegner, W.E., 1954, Beyond the hundredth meridian: John Wesley Powell and the second opening of the west: Penquin Books, 496 p., 1992 reprint. Quote from p. 215-216 of 1992 reprint.