Links: Field tripping in Nevada, mostly along I-80 and Highway 50

A River Runs through It [link to download], ESW 2016, E-59 NBMG: Truckee River Reno to Pyramid Lake

1915 Pleasant Valley earthquake centennial field trip guidebook: A public field trip to visit the largest earthquake in Nevada's history [link to download] E-58 NBMG: 50 miles south of Winnemucca

Fire and Ice—Geology of the Mount Rose quadrangle, Lake Tahoe, and the Carson Range [link to download pdf], ESW 2015, E-57 NBMG: Galena Creek Visitor Center to Incline Village

Carson Rocks! A Sesquicentennial Celebration of some of our Capital City's Geological High Points [link to download pdf], ESW 2014, E-56 NBMG: around Carson City

Geo- and Eco-Mapping around DRI (The Great Altered Rock Walking Tour) [link download pdf], 2014, E-55, NBMG: around DRI.

Mapping the Geology around the Desert Research Institute and Truckee Meadows Community College [pdf], ESW 2013, E-53, NBMG: around DRI.

"Tuff All Over": Exploring Faulted Volcanic Terrain in the Painted Hills, Virginia Mountains, West of Pyramid Lake [pdf], ESW 2012, E-52, NBMG: near Pyramid Lake.

"Life's a Beach": In Search of Ancient Shorelines and Volcanoes in the Grimes Point and Lahontan Mountains Area [pdf], ESW 2011, E-51, NBMG: near Fallon.

Geo-tripping in Nevada [pdf], NBMG map guide to many or most of the NBMG field trip guides in Nevada through E-50.

In search of Tufa, Tuff, and Tough Rocks [link to download pdf], ESW 2010, E-50, NBMG: stops are east of Pyramid Lake; trip guide includes Reno to Pyramid Lake, Pyramid Lake to Wadsworth, Pyramid Lake to Brady's Hot Springs, Brady's Hot Springs to Reno.

Digging Deeper into the Comstock [link to download pdf], ESW 2009, E-48, NBMG: Reno to Gold Hill.

No Child Left Inside: A field trip for Families and Rockhounds [link to download pdf], ESW 2008, E-47, NBMG: stops are near Fallon, east of Fallon, north of Fallon, and in the Truckee River Canyon along I-80; road guide runs from Reno to east of Fallon, Fallon to Trinity (junction of I-80 and 95), and Trinity to Reno.

Taking the Pulse of the Earth [link to download pdf], ESW 2007, E-46, NBMG: south of Reno (Slide Mountain, Steamboat, and Virginia Foothills; the latter two not available to public).

Rockin' Along the River [link to download pdf], ESW 2006, E-45 NMBG: Truckee River Verdi to Wadsworth

The great Highway 50 rock tour [link to download], ESW 2005, E-44 NBMG: Fallon to Middlegate

The Frenchman lake frolic [link to download], ESW 2004, E-43 NBMG: Frenchman Lake area, California, west of NV-CA border.

Get out, stay out, and stay alive [link to download], ESW 2003, E-42 NBMG: north of Reno towards Pyramid Lake.

In search of "the right tuff" but you can just "take it for granite" [link to download], ESW 2002, E-41 NBMG: north of Reno and to the west toward northern end of Red Rock Road.

Fossils and Ancient Lakes [link to download pdf], ESW 2001 field trip #2, E-40, NBMG: fossils near Nightingale.

Peavine Peak: Geology, plants, and mining history [link to download], ESW 2001 field trip #1, E-39, NBMG: Peavine.

Exploring east of the summit: A field trip guide to Steamboat Springs, Lake Tahoe, and the Comstock area [link to download pdf], ESW 2000, E-38 NBMG: Steamboat Springs, Lake Tahoe, Comstock.

Geology along America's loneliest highway [link to download pdf], ESW 2000 E-37 NBMG: Carson to Sand Mountain.

What's shakin' in the neighborhood? -- Road log [link to download pdf], ESW 1999 field trip #2, E-34 NBMG:  Reno, Mt. Rose fan/pediment, to Genoa fault scarp.

Turbulent times in the Truckee Meadows [link to download pdf], ESW 1999 field trip #1, E-33 NBMG: UNR to Verdi to Crystal Peak Mine.

Ancient lakes and volcanoes near Fallon: Field trip for families and rockhounds [link to download pdf], ESW 1998, E-28 NBMG: Fallon, Grimes Point, Soda Lake.

Link to NBMG's entire Educational series; most (all?) are available to download.

INQUA 2003 - Elko to Reno, Wadsworth Amp, Lone Mtn hwy 50, Reheis - no viewing online at Google books

Geothermal energy helps power Nevada | Elko Daily Free Press - Brady's Hot Spring, Beowawe, and "Hot Hole" in Elko

The Stories Behind I-80s Exit Sign Names - Part 1 | Backyard Traveler by Rich Moreno - various info about signs and areas, e.g., Nightingale and Brady's Hot Springs

Touring California and Nevada hot springs | Matt C. Bischoff - Brady's Hot Springs reaches 209*F (and other tidbits)

Links: The Sump, Nevada

This is about as close as I've gotten to The Sump, a place in Nevada that I had never heard of until I was doing some research into stops for our Death Valley trip of last February. And mind you, the declivity I've pointed out in the photo above is just the southern entrance to this apparently intriguing place. Fossils have been found here!

While trying to figure out if The Sump would be a stop along the way or the way back (it wasn't), I collected a few links. Most of the links show only one picture from the place; a few show more. I'll leave it to you to do more investigation (and visitation, I hope!). The links are listed rather randomly. Links about the fossils, in particular, are at the bottom.

The "Sump"—Strange Name but Amazing Place - Backyard Traveler by Richard Moreno

The Sump, Esmeralda County, Nevada - Eastern Mojave Vegetation (schweich.com)

The Sump Canyon paradise - Terry's World (Terry Wright, geologist)

The Sump (Esmeralda County, Nevada) - Weekend Wanderluster

The Fossils:
Hardy, F.C., and Bonde, J., 2015, Stomping Around the Sump: Miocene Pygmy Gomphothere from Esmeralda County, Nevada [also here], in Pennell, W.M., and Garside, L.J., eds., New Concepts and Discoveries: GSN 2015 Symposium Proceedings: Geological Society of Nevada, p. 929-937.

Sand and Bone - a photo slide show (in color): "Go along with a band of UNLV researchers as they uncover the skull of an extinct elephant-like creature that once roamed Esmeralda County."

Photo Essay: In the Footsteps of the Elephant -  VegasSeven (really nice B&W photos)

Approach to Titus Canyon: To Red Pass

It looks to me like you can see Quail Rock from White Pass!

We've gone over White Pass—btw, here's a gigapan looking west from White Pass—and we've gone across the flats in the east fork of upper Titanothere Canyon. The road has become a fairly normal dirt road, and although it's still a little narrow, there are places to pull over, or pass, if you happen to be traveling faster than someone ahead of you—although by this point on the road, there is plenty to look at, everywhere, all around, so going slow behind someone (back far enough not to eat any of their dust) is an acceptable option. All through this section, until about the unnamed pass between the east and west forks of upper Titanothere Canyon, the age of the rock formations is Cambrian to the south and Tertiary to the north. The unnamed pass is marked by "Gate" and a gate symbol on the USGS topographic map of the area (USGS TNM 2.0 Viewer)—not that I noticed a gate.

The geology changes a little at the unnamed pass, and the road goes into a series of curves, while also going up and down quite a bit. We've entered the territory of the Tertiary Titus Canyon Formation. The exposures right along the road from here to Red Pass will be either Titus Canyon Formation or Cambrian formations, though not much of the latter, and none that I have photos of.

This photo looks up the western branch of the western fork of upper Titanothere Canyon (Titanothere Canyon is not actually divided into forks and branches, but I've got to call them something!). A fault runs up this canyon, dropping the Tertiary section downward on the northeast (right) side.

You can see the southeast-northwest trending fault in this geologic overlay I made on Google Earth (G.E.). The geology is from Niemi, 2012. Using the "Add Path" feature of G.E. creates lines that hang up in the air above the topography in places, making the contacts as drawn look a little ragged. They also disappear behind topography, going in and out unexpectedly in places, so they are best used for quick visualization. My drawing of the contacts may not be precise, as Niemi's geologic map wasn't associated with an air photo (as published, anyway), and his topo base was digitized somehow, so it doesn't correlate directly with USGS topographic maps (TNM 2.0 Viewer), which can be directly correlated with air photos. I also may have modified some contacts based on what I was seeing on the air photos (G.E.).

Here, above and below, we can begin to see a little of the geology, including a lot of Quaternary alluvium (Q). Notice the terraces of older alluvium, especially the nice one up the canyon. And, by the way, I use blue for faults.

I've labeled the foreground units, from EOgtc to Q (Quaternary undivided). I've emphasized the southeast-northwest trending fault I mentioned earlier by thickening the blue line to the right of the little canyon we're looking up.

Most of these formations were described in a little detail in my last post. Briefly, the Trp is the Miocene Rhyolite of Picture rock, a rhyodacite to latite flow; the Tw is the Miocene Wahguyhe Formation; the Tg is the Miocene Panuga Formation; and the EOgtc is the latest Eocene to Oligocene Titus Canyon Formation. What is shown as Tg in these posts (and on Niemi's map) was once considered to be the upper part of the Titus Canyon Formation, a section known as the Green Conglomerate facies, which sits atop a disconformity on the Variegated facies of the Titus Canyon Formation, formerly considered to be the middle unit of the Titus. All that changed with the publication of Snow and Lux's Tectono-sequence stratigraphy of Tertiary rocks, California and Nevada in 1999, when the Green Conglomerate facies was assigned to the Panuga.

Below, you can see the sort of thing one can work with if geologic contacts are transferred to Google Earth.

This map is a small portion of Niemi's 2012 geologic map of the central Grapevine Mountains.

This image overlays Niemi's map (above) fairly well. I'm sure there is some distortion, and I didn't mean to leave my photo locations turned on!! I've extended a fault or two based on the air photo imagery in G.E.

Not far past this stop, beyond the sharp curve shown in the second photo and the images above, the road crosses a fairly major fault. (This fault is shown as "Fault Zone" in the portion of Niemi's map shown above; it's actually labeled "Fall Canyon Fault Zone" on the full map. I'm not sure if that is really correct, since the Fall Canyon Fault is actually in Fall Canyon, quite a ways to the west. Possibly this fault is considered part of a much larger Fall Canyon Fault Zone: It is parallel in part to the Fall Canyon Fault. (There are at least a couple "drafting" boo-boos I noticed on the map, besides this possible glitch. Labeling and coloring mistakes on published maps is really not uncommon, if you look closely.)

We're getting closer and closer to Red Pass. MOH and I decided to pull over in a slightly wide spot near the next curve so we could hike around a little and look at rocks. I took the next photo just before that curve, primarily to grab a shot of what appears to be an example of two normal faults forming a small, asymmetrical graben on the hill beyond the curve.

Is this a small graben?

A closer view of the hypothetical graben.

The top of the crystal tuff (xtl tuff) formerly marked the change from middle Titus Canyon Formation to upper Titus Canyon Formation. This generally greenish formation is now assigned to the Panuga Formation (Tg).

Looking around from various angles on Google Earth, I have to conclude that there is definitely something going on up there, probably more than two intersecting joints, although the offset on both structures is quite small.

The two hypothesized faults, as seen from a different angle thanks to G.E. The lower, lighter cyan line marks the base of the crystal tuff seen in the last photo.

The crystal tuff has been correlated with the 15.7 Ma Tuff of Unconformity Hill (Snow and Lux, 1999).

A bit of the Titus Canyon Formation, I'm not sure which part.

Here's a nice piece of gneiss (yes, we geologists really say things like that), a boulder that was once a rounded clast, probably in the Titus Canyon Fm, but possibly in the overlying Panuga Formation. "RUB" in Rubicon for scale.

From this same spot, we get a great glimpse of our next section of road: the climb up Red Pass.

We're looking in a southerly direction at the main switchback going up Red Pass. You can see why it's called Red Pass!

The road through here is in the Variegated facies of the Titus Canyon Formation, according to Lengner and Troxel (2008). I'll have to trust them on this. It is within the lower portion of the Variegated facies that late Eocene to early Oligocene fossils have been found (Lengner and Troxel, 2008), including the fossil Titanothere (Protitanops curryi) for which Titanothere Canyon was named. Read more about the Titanothere and other fossil finds here at Geotripper.

With this next photo, we've begun to climb the east side of Red Pass. We turn back around, after pulling over to the side, to see where we've been. The unnamed pass is right at that little white bit of road nearly at the center of the next photo. Just below that section of road, you see the Cambrian part of the latest piece of our journey: The jagged reddish brown rocks on the right side of the photo (south) are Cambrian Zabriskie Quartzite dipping northward (left), overlain by a thin, dark gray section of rock mapped as Cambrian Carrara Formation (although on G.E. the rock looks about the same as the Cambrian Bonanza King Formation did near White Pass).

We're looking northeast into the part of upper Titanothere Canyon.

With that view, we'll stop for now. We'll climb up Red Pass next time. While you're waiting, check out this great gigapan by Ron Schott, which looks like it was created at about the same spot I took the last photo.

A Few References:
Lengner, K., and Troxel, B.W., 2008, Death Valley's Titus Canyon & Leadfield ghost town: Deep Enough Press, 175 p.

Niemi, N.A., 2012, Geologic Map of the Central Grapevine Mountains, Inyo County, California, and Esmeralda and Nye Counties, Nevada: Nevada, Geological Society of America Digital Maps and Charts Series, DMC12, 1:48,000, 28 p. text.

Snow, J.K., and Lux, D.R., 1999, Tectono-sequence stratigraphy of Tertiaryrocks in the Cottonwood Mountain and northern Death Valley area, Californiaand Nevada, in Wright, L.A. and Troxel, B.W. eds., Cenozoic basinsof the Death Valley region: Geological Society of America Special Paper 333, p. 17–64.

Location map

Related Posts:
Beatty: Old Buildings, A Fold, and Onward toward Titus Canyon

The Approach to Titus Canyon: Amargosa Narrows, Bullfrog Pit, and the Original Bullfrog Mine

Mineral Monday: Close-Ups of Bullfrog Ore from the Original Bullfrog Mine, Nevada

The Approach to Titus Canyon: Tan Mountain

The Approach to Titus Canyon: Up and over White Pass

Inversion!

When we got back from Alaska after Xmas, northern and western Nevada was locked into a classic mid-winter high-pressure system, with a surface temperature inversion creating below average low temperatures on the valley floors (and higher temperatures in the mountains and at local ski resorts, something we did not actually check out this time). Classic Great Basin inversions with severe Pogonip events in the past have had people skiing in shirt sleeves in essentially spring skiing conditions (slushy snow) on Mt. Rose, while temperatures in the valley were -20°F or lower.

In fact, because of the Chinook that came in while we were up north, temps in Nevada were considerably colder than they were in Alaska. Reno was running lows of 10 to 16°F and highs of 30 to 33°F while Anchorage ran lows of 21 to 33°F and highs of 30 to 43°F. Our destination location, which we drove to on I-80 on January 5th (photos below), was having lows of -10 to -16°F and highs of 17 to 22°F.

Looking northeast along I-80 and the Fortymile Desert.

Steam from the geothermal plant at Brady's Hot Springs is rising straight into the air, one hallmark of high pressure and inversion.

The low hills of the Hot Springs Mountains fade into a smoggy haze. Wave-cut terraces of Lake Lahontan are enhanced by the thin snow cover.

Approaching the geothermal plant at Brady's Hot Springs, AKA Nightingale Hot Springs (see location at the end of the post).

A closer view of the steam from the geothermal plant at Brady's Hot Springs, which is mostly used to roast or dry onions.

By the way, although these hot springs are among the hottest in Nevada, at 83 to 98°C (181 to 209°F), they are entirely private, and can't be accessed by the likes of you or me. The Nightingale Hot Springs Exit provides access to the geothermal plant and a nearby fossil collecting area.

Looking northeast down I-80 and the Fortymile Desert
toward the West Humboldt Range.

The Humboldt Range is about 6 miles distant on the far right of the photo, beyond a dark, gently sloping hill, and is about 34 miles distant looking straight down the highway.

Looking south toward the east edge of the Hot Springs Mountains on the right, and at the hazy, fading Stillwater Range beyond the Carson Sink, center and left.

Tufa mounds in the Fortymile Desert on a Lahontan shoreline or terrace in the foreground; the West Humboldt Range 9 miles away in the left middle ground;
the hazy Stillwater Range in the far distance about 35+ miles (58+ km) away.

Location of the tufa mounds, from the USGS TNM 2.0 Viewer.

The hazy day didn't make for optimal photos: snow on the ground was bright white, the mountains in the distance were hazy white, and everything blended together. Finally, approaching our northern Nevada destination, the closer mountains offered bits of photogenic opportunities.

Blue Mountain.

I'll have to update my song about Blue Mountain, as it obviously becomes covered with snow in winter time!

View Blue Mountain in Larger Map

Winnemucca Mountain.

View Winnemucca Mountain in Larger Map

After a few days, the high pressure and accompanying inversion dispersed, and light to moderate snowfall came into the area. And now, the cold valley temperatures are back: it was -15°F this morning at the airport, though only -4 or so at our banana belt location. As per the National Weather Service, "LOWS AT NIGHT WILL GENERALLY RANGE FROM 5 TO 15 BELOW ZERO WITH DAYTIME HIGHS OF 10 TO 20 DEGREES" into the forseeable future (link to this statement is probably not a permalink).

Geo-beers: Gimme an Icky

Ichthyosaur "Icky" IPA, usually known as "Icky," is a true geo-beer, made by geologists for geologists — and for Nevadans and all beer lovers. It's named after our official state fossil, the Ichthyosaur, found and preserved at Berlin-Ichthyosaur State Park.

"Distinct, not extinct."

Icky is one of my ultimate favorites — especially for a local, often on-tap beer (on tap at least as far east as Winnemucca, NV) — competing quite nicely with all my other favorite local, Alaskan, and IPA brews. (Okay, so the last two are Alaskan.)

"A brew more than 200 million years in the making."
"You better hold on tight. This is one tough species."
"PROTECT THE SPECIES. Enjoy a long-necked Ichthyosaur today."
and
"Do as the locals do - say "GIMME AN ICKY".
"A highly evolved brew."
"Savor the pioneering spirit of the Great Basin."
"Named after Nevada's official state fossil."

I don't, currently, have an actual photo of an Icky, but I hope to remedy that lack sometime in the next few days, when I will finish logging the hole I'm on and take some well-earned days off.

Great Basin Brewing Co.
Icky IPA

UPDATE: See Accretionary Wedge #54 for more interesting posts about beer and other libations.

A Few Nevada Turbidite References

Crafford, A.E.J., 2007, Geologic Map of Nevada: U.S. Geological Survey Data Series 249, 1 CD-ROM, 46 p., 1 plate [link to pamphlet/description accompanying the map].

Dean, Nicole, Houston, Shauna, and Swanson, Karl, 2002, Geology of the White Pine Mts. along Highway 50, eastern Nevada, 2001 Geology Field Camp: Geological Society of America Abstracts with Programs, v. 34, no. 6, page unknown.

Dickinson, W.R., 2006, Geotectonic evolution of the Great Basin: Geosphere, v. 2, no. 7, p. 353–368; doi: 10.1130/GES00054.1.

Dickinson, W.R., Saller, A.H., 1982, Alluvial to marine facies transition in the Antler overlap sequence, Pennsylvanian and Permian of north-central Nevada: Journal of Sedimentary Petrology, v. 52, no. 3, p. 925-940; doi: 10.1306/212F8094-2B24-11D7-8648000102C1865D [link to abstract].

Fagan, J.J., 1962, Carboniferous cherts, turbidites, and volcanic rocks in northern Independence Range, Nevada: Geological Society of America Bulletin, v. 73, p. 595-612; doi: 10.1130/0016-7606(1962) 73[595:CCTAVR] 2.0.CO;2 [link to abstract].

Keppie, J.D., Boyle, R.W., and Haynes, S.J., 1986, Turbidite-hosted gold deposits: Geological Association of Canada, Special Paper 32, 186 p.

Ludington, Steve, McKee, E.H., Cox, D.P., Moring, B.C., and Leonard, K.R., 1996, Pre-Tertiary geology of Nevada, Chapter 4 in Singer, D.A., ed., An analysis of Nevada's metal-bearing mineral resources: Nevada Bureau of Mines and Geology Open-File Report 96-2, p. 4.1-4.17, 1 sheet, scale 1:1,000,000.

Mattinson, C.G., and Tiffney, B.H., 2001, Terrestrial plant fossils from the Mississippian Diamond Peak Formation, White Pine Range, eastern Nevada: PaleoBios, v. 21, no. 3., p. 1–11.

Theodore, T.G., 2000, Geology of pluton-related gold mineralization at Battle Mountain, Nevada: Tucson, Arizona, Center for Mineral Resources, Monographs in Mineral Resources Sciences, 271 p [link to purchase].

Watkins, Rodney, and Browne, Q.J., 1989, An Ordovician continental-margin sequence of turbidite and seamount deposits in the Roberts Mountains allochthon, Independence Range, Nevada: Geological Society of America Bulletin, v. 101, no. 5, p. 731-741; DOI: 10.1130/0016-7606(1989)101<0731:aocmso>2.3.CO;2 [link to abstract].

Geology off the Road: a bit of Tuff, Fossil Leaves, and EarthScope

It was a gray, early December day, but we continued our exploration on backroads near Middlegate Station. From the the exposures of flow-banded and brecciated rhyolite near Highway 50 — this was before The Shoe Tree had been cut down and could be used as an excellent landmark — we headed north on the main dirt road into the valley between the two southern branches of the Clan Alpine Mountains, the valley of Bench Creek. We took a sharp right at the first opportunity, within about a half mile of the pavement (the turn can be seen in the next-to-last picture of the previous post in this series).
The side road took us up the main wash, where we were tasked with looking for "little white flakes" of the middle Miocene Middlegate Formation, a formation composed of coarse- to fine-grained, often tuffaceous, sometimes zeolitized lacustrine sediments with interbeds of tuff, all lying unconformably on the older volcanic rocks of the Clan Alpine and Desatoya Mountains. A short distance up the wash road, we came to this exposure of white rocks... and though the weathering pattern looked blocky rather than flaky to me, we stopped to check it out.

Darn, we'd pulled over for a poorly welded lithic-rich ash-flow tuff, no doubt older than the rocks we were looking for. We moved on quickly, continuing up the wash.
Following the main wash road as we had been instructed by a hand-drawn map given to us at Middlegate Station, we finally came to a saddle overlooking this sedimentary section. These are the same tuffaceous sediments that can be seen north of Highway 50 when driving between Cold Springs and Middlegate gap, where the Shoe Tree used to live. The sediments were deposited in a small Miocene basin known as Middlegate Basin. Leaf fossils and petrified wood are reported in these rocks, and the zeolite erionite has been mined, at least in a small way, near the junction of S.R. 722 (old Highway 50, former Route 2) and Highway 50.
We trekked over to the white patches we could see from the saddle, and wandered around the overly muddy area looking for leaf fossils, breaking open numerous small slabs of white tuffaceous shale. We were unsuccessful for some time, and that's because we were in the wrong place. Close, but not quite.

Part of the Eastgate 1:24,000 topo map via MSRMaps courtesy USGS; X marks the saddle, not the fossil locations; sections are a mile on each side.

The saddle roads form a crude X in the center of this Google Earth image.

In order to find the fossils, you should not stop at the saddle (we had turned left and had parked on the narrow muddy ridge northwest of the saddle) but should instead keep driving down a fairly steep over-the-saddle road to the ENE; then, near the bottom of the hill, you should turn and drive southeast down another wash to a main wash heading SSE to south. In fact, while wandering around before driving over to the one fossil site we found, we could see a small hill with small diggings. That hill, located near the bottom of the GE image, is where we found the fossils.
It looked like the area had been pretty well picked over — we banged around quite a bit and only took these meager specimens. I suspect there are better localities, possibly shown here. I haven't the vaguest idea which of the many possible Middlegate flora leaf types (or stems, seeds) are represented by our bits and pieces. See these three lists (from Table 1 in Axlerod, 1985).

This plant growing near the saddle caught our eye as an unusual bush, then after our eyes became attuned to it, we saw it everywhere.

After fossil hunting, we tried to exit southward out of the wash. It was ultimately too muddy, and I don't think it's easy to find an Eastgate Wash crossing without a good map or current air photo. So we drove back to the saddle, up the steep road, and back down to the main wash road.
After trying for some unknown reason to drive south toward The Shoe Tree, and then stopping just barely in time before entering an impassable field of mud, we drove back to the main wash road and saw a fence on a little hill. We drove up to it and found this EarthScope installation.
This particular EarthScope observatory, is one of several plate boundary observatories strung across central Nevada near Highway 50.
This is Station P068's GPS receiver, with Fairview Peak in the background.
As we leave the wash, near our first tuff stop, Fairview Peak looms in the distance.

Some References:
Axlerod, D.I., 1956, Mio-Pliocene floras from west-central Nevada: University of California Press, 54 pp.

Axlerod, D.I., 1957, Late Tertiary floras and the Sierra Nevada uplift: Geological Society of America Bulletin, vol. 68, p. 19-46 [abstract].

Axlerod, D.I., 1985, Miocene floras from the Middlegate Basin, west-central Nevada: University of California Press, 279 pp.

Barrows, K.J., 1980, Zeolitization of Miocene volcaniclastic rocks, southern Desatoya Mountains, Nevada: Geological Society of America Bulletin, v. 91, no. 4, p. 199-210 [abstract].

Burke, D.B., and McKee, E.H., 1979, Mid-Cenozoic volcano-tectonic troughs in central Nevada: Geological Society of America Bulletin, v. 90; no. 2, p. 181-184 [abstract].

Eakin, T.E., 1962, Ground-water appraisal of Gabbs Valley, Mineral and Nye Counties, Nevada: Nevada Department of Conservation and Natural Resources, in Ground-water Resources - Reconnaissance Series Report 9, 54 pp.

Papke, K.G., 1972, Erionite and other associated zeolites in Nevada: Nevada Bureau of Mines and Geology, Bulletin 79, 36 pp [link to purchase].

2010 Oregon Trip Series

While going through my posts for the last two memes (12MoMeme and travel meme), I noticed a lot of unfinished business. I have a huge number of drafts (87!), many of which will never see the light of day, but which I hesitate to delete for various reasons. And I have a few ongoing or nearly complete series. Some of the series will, with any luck, be picked up next year. The Oregon Trip series is nearly complete, but needs to be posted all in one place, for my sake if for no one else's. So here goes.

In late July, MOH and I took a trip to central Oregon for a family reunion. We took four days in getting there, we spent three days there, and we took two days in coming back. For the first four days, I have four rather long posts with lots of pictures. For the three days in central Oregon, I have four posts, all from a single geological field trip on one day. For the two days coming back, I so far have six posts, and haven't even gotten us back to Winnemucca. When that will happen remains to be seen; the last post was written in October. So, this is it: the 2010 Oregon Series as it stands now, with a good deal of geology, lots of photos, some flora and fauna, and a few scattered beers and brewpubs. The geology seems heavy on the volcanic rocks and volcanoes, perhaps fitting for a central Oregon trip.

Getting There:
Oregon Trip Day 1: A Brewery, Some Geology, Wildlife, and Other Stuff: To Jarbidge, NV, via the Ruby Mountain Brewery. Includes the Great Basin to Snake River Plain transition, mesas capped by ash-flow tuff, an intrusive contact, an old hot spring or two, a basalt dike, wildlife, and more.

Oregon Trip Day 2: A Hike near Jarbidge across Two Rhyolites: Jarbidge, NV. Includes the Jarbidge Rhyolite, Cougar Point Tuff, flow foliation and flow lineation, trees, wildflowers, and the canyon of the Jarbidge River.

Oregon Trip Day 3: Hoodoos, a Snake, more Rhyolite, and Another Brewery: Jarbidge, NV, to Baker City, OR. Includes the Red Dog Saloon, hoodoos in the Cougar Point Tuff, the Jarbidge Forks, jointing in the Dorsey Creek Rhyolite, a snake, a marmot, Salmon Falls Dam, waterfalls into the Snake River at Thousand Springs, and Barley Brown's Brew Pub.

Oregon Trip Day 4: Coffee, Fossils, Formations, Basalt, and Brew: Baker City, OR, to Redmond, OR. Includes a bit of Baker City, part of the Blue Mountains, larch and other trees, John Day Fossil Beds at Sheep Rock, the Columbia River Basalt Group with columnar jointing, the Rattlesnake Tuff and other ignimbrites, and the Red Dog Depot.

Our Field Trip:
Travel Tuesday: Central Oregon: A few pictures from Smith Rock State Park near Terrebonne, OR, and the Terrebonne Depot with Terminal Gravity IPA.

Oregon Trip Day 7: The Tuff of Smith Rock: The tuff of Smith Rock at Smith Rock State Park near Terrebonne, OR, with photos of distant Cascade volcanoes and columnar-jointed basalt.

Oregon Trip Day 7: The Petersen Rock Garden: The Petersen Rock Garden near Redmond, OR, with rocks, lots of rocks, ponds, and peacocks.

Oregon Trip Day 7: A Volcano Observatory: The Dee Wright Observatory on McKenzie Pass, with lots of volcanoes and volcanic rocks, birds, threatening clouds, and a bit of Sisters, Oregon.

The Return Trip:
Travel Tuesday: Cliff near Summer Lake, Oregon: A neat volcanic cliff, with basalt and interlayered volcanic ash or tuff, and a mosquito festival in Paisley.

Ancient Shorelines and a Basalt Dike southeast of Paisley, Oregon: Shorelines of ancient Lake Chewaucan and a basalt dike.

Turning Off onto the Winnemucca-to-the-Sea Highway: North of Lakeview, OR. The turnoff from Highway 95 to Highway 140, with a song that mentions Winnemucca.

Friday Field Photos: Mystery Cracks: West of Adel, OR. Some columnar-jointed basalt with possible spheroidal weathering.

Deep Creek Falls: Continuation of our Oregon Roadtrip: West of Adel, OR. A nice waterfalls over columnar-jointed basalt.

Highway 8A: The Cutoff from Cedarville to the Winnemucca-to-the-Sea Highway: Oregon-Nevada state line on Highway 140 to the junction with Highway 8A. Signs, roads, more signs, and 8A stories.

Onward to Denio Junction!: Highway 140 from its junction with S.R. 8A to Denio Junction. Volcanic flow (rhyolite?) and roadside sediments, signs, and the oasis of Denio Junction.

Onward to Winnemucca!

Oregon Trip Day 4: Coffee, Fossils, Formations, Basalt, and Brew

Now that I've gotten back from driving through a low desert locality with huge mountains on the western side of the valley, and then driving across central Nevada on one of the dustiest roads in existence, we can return to the trip to Oregon that MOH and I took last month. Where were we? Oh yeah, we had traveled from Jarbidge, NV, to Baker City, OR, on various backroads and I-84.

The morning after attending Barley Brown's Brew Pub, we awoke in our strange motel room (Google Maps), and after checking out the okay but crowded coffee and continental breakfast, we opted for some real coffee and walked downtown to a small cafe that had espresso (Google Maps). We sat outside and enjoyed the view of the brightly colored town of Baker City.
Eventually we packed our stuff into the Prius, bought more ice for the Ruby Mountain beer in our ice chest, and headed down Oregon Route 7 toward U.S. Route 26, which we joined at Austin Junction. Between Austin Junction and Prairie City, we crossed over a small part of the famed Blue Mountains. The Blue Mountains are high, cool, and covered with a mixed conifer forest, species of which include one of my favorite tree, the larch.
Just west of Dixie Summit, we walked a short trail down to a small section of track that has been laid on the old Sumpter Valley Railroad grade (Google Maps Street View). It's a nice place to take a little break from driving.
The third main highlight of the day was coming to the Sheep Rock Unit of the John Day Fossil Beds National Monument, which is mostly north of Highway 26 (MSRMaps, in purple). This national monument comes in three main pieces scattered over eastern Oregon, and the fossils are in several fossil assemblages that range in age from 44 to 7 Ma. I'm not going to get into the palaeontology in any detail, but will to say that the Thomas Condon Paleontology Center has a huge display of ancient flora and fauna including lots of mammal, reptile, and amphibian bones and skulls, and lots plant fossils including nuts and leaves. This first overlook (Google Maps) is of the Mascall Formation, one of the youngest mammal-bearing formations in the park, about 12 to 16 million years old.

The Mascall Formation forms nice badlands of tilted strata overlying flows of the tilted Picture Gorge Basalt (about 16 Ma, in part correlative to basalts seen at Multnomah Falls, and part of the Columbia River Basalt Group). The Mascall is capped by the nearly flat-lying Rattlesnake Tuff, the thin orange-brown unit on the mesa. At first I thought — no, this is Oregon, that must be basalt. I later realized that the Rattlesnake Tuff is a widespread ash-flow tuff unit, often called an ignimbrite at John Day, which erupted 7 million years ago and covered a 30,000 to 40,000 km2 area (as much as 15,000 square miles) of eastern to central Oregon. It's present-day distribution can be seen here.
So now, everytime I see a thin, reddish to orangish brown unit amongst a bunch of basalt flows, I wonder...
From the Mascall overlook, we looked north along Highway 26 and the John Day River, into Picture Gorge. Just beyond Picture Gorge, you can see a bit of Sheep Rock sticking up, also capped by the 16 Ma Picture Gorge Basalt.
We're getting closer: this is the part of Picture Gorge where Rock Creek flows in from the west to join the John Day River flowing north toward Sheep Rock.
This is the view of Sheep Rock from the Thomas Condon Paleontology and Visitor Center (Google Maps location). The dark, capping layers are flows of the Picture Gorge Basalt (16 Ma); the central brownish layer is the Picture Gorge Ignimbrite (28.7 Ma). The upper buff to pinkish layers are ashy claystones of the Kimberly Formation (25 to 28 Ma). The lower greenish sediments are ashy claystones of the Turtle Cove Formation (28 to 33 Ma); the green Turtle Cove sediments lie mostly below the Picture Gorge Ignimbrite but also form a thin band above it. The entire section below the capping basalt is part of the John Day Group.
A matching photo with some explanations from the Visitor Center (click to enlarge).
Zooming in on the Picture Gorge Ignimbrite and the greenish layers below, we can see a fault offsetting the units. The thin white cliffy unit in the middle of the lower section is the Blue Basin Tuff (28.9 Ma). This tuff layer, along with a couple other tuffs and many other sub-units used for correlating different fossil beds, can be see below (click to enlarge). Read more about the stratigraphy and regional geology here. My blathering doesn't really do it justice!
The ranger giving an overview of the geology preferred not to use the word fault for the planar-looking structure seen offsetting the units in the previous four photos — and it's called a "minor fault" in displays inside — instead calling it a "crack." I think this was to emphasize that the structure is an old, inactive fault that people shouldn't be afraid of, rather than an "earthquake fault" about to go off at any moment, but possibly he meant it was a growth fault that didn't extend upward through the entire section.

Also, he apparently had to explain constantly that there aren't any dinosaurs at the museum because the fossils are from the Age of Mammals. I guess some people come expecting or hoping to see dinosaurs, but the sediments and tuffs post-date the KT boundary and dinosaurs by about 20 to 60 million years.

It was very hot when we were at John Day Fossil Beds in late July — go early in the morning if it's summer, or wait until fall!
So, we left without taking any planned hikes: the road had been long and we still had miles to go — and it was cooler in the Prius. We could follow some of the formations westward toward Redmond, but we finally lost track of whether we were seeing the Rattlesnake Tuff or the same basalts.
After settling in at a nice but inexpensive motel in Redmond, we met some Alaskans and joined them for dinner and ale at the Red Dog Depot.
I can't really say what kind of IPA was favored, because they changed the available beers almost daily. One was less hoppy than the other; both were less hoppy than the WFO IPA at Barley Brown's in Baker City. The 20" Brown was enjoyed by non-IPA drinkers.


View Baker City, OR to Redmond, OR in a larger map

Trip report to be continued... (although I will skip a couple non-travel days).