Friday, December 31, 2010

Most Popular Posts from 2010

Yes, it's the time of year when many bloggers go all retrospective on you, at least to some extent, and so I've made a list. Included here are my Top Twenty geological posts as ranked by a complicated cobbled-together .xls formula combining several different sets of stats (see endnote), along with a smattering of other noteworthy posts, particularly some near the beginning of the year when I had incomplete analytics. I've listed these prime posts by date.

January-March

April-July

August

September-December


Note: Three of the stat programs I use don't go back to the beginning of the year: I've used FeedBurner stats for a couple-three years, started using PostRank during the middle of February, and started using Google Analytics toward the end of June. The internal Blogger stats only go back to early June and don't show stats for all posts, just the top ten. These several analytics programs came up with different rankings, with only the top two to three really agreeing (with FeedBurner being hard to evaluate), so besides combining the rankings, I also checked posts against comment popularity and added a few from the beginning of the year when analytic coverage was thin.

Wednesday, December 29, 2010

A Page of Inactive GeoBlogs

These are geoblogs that have moved or have been inactive through all or most of 2010 [updated early 2012 late 2013]; many have been inactive longer than that. There are several classics on this list, which are worth perusing if you haven't already. I'll leave you to the exploring.

+/- Science

Active Margin

Adventures in Geology and GeoHazards

All of My Faults are Stress Related (Sb) - back at All of My Faults are Stress-Related - both inactive

A Long Way to Go

Antimonite (offline)

Apparent Dip

Arctic, Antarctic and Alpine

Arizona State Mine Inspector

Around the Bend

Awesome Froth (offline)

Barriers explained!

Beyond the Moho

Cambriangirl (offline)

Carbonate Sedimentology

Cataclasis

Christie at the Cape

Chrsphr (offline?)

Cindy_L

Clastic Detritus - moved to Clastic Detritus (Wired)
Clastic Detritus (Wired) - moved back to Clastic Detritus

Communicating Geoscience

cryology and co.  - see David Bressan here and here

Crystallizations

Daisy's Geology Blog (offline)

Dave's Landslide Blog - moved to The Landslide Blog (AGU)

Dracovenator (blogspot) - now at Dracovenator

Dendritic Impressions

Denison Geoblog (offline) - now active!!

Dude Diligence

Dynamic Earth- now reactivated!! - now inactivated again :(

Earth InsightCache

Earth Science Erratics - currently inactive but available for guest posts!

EarthTime

Eat. Sleep. Geology

Eclectic Plagiodoxy -- occasionally active

Educated Erosion

EffJot- now reactivated!!

Emily Erratic

En Morrenas

En Tequila Es Verdad (blogspot) - now at En Tequila Es Verdad (Freethought Blogs)

Eruptions (Sb) - moved to Eruptions (Big Think)
Eruptions (Big Think) - now at Eruptions (Wired)

ESPM-Earth Sci Processes at Manchester

EXPLICITLY UNEXPLICIT - appears to be offline 12Feb2012

Extremofiles

FLC Geo News

geoberg.de (german) and geoberg.de (english)

GeoCastAway (blogspot) - now at GeoCastAway

Geologia Marinha e Costeria

Geologic Froth - moved to Geologic Froth (dead link) - move to Geologic Froth (also dead?) - UPDATE: now possibly archived here.

Geologic Frothings - also moved to Geologic Froth (dead link) - moved to Geologic Froth (also dead) - UPDATE: moved to GeoFroth, although this also seems inactive.

(NOTE: I find all these many versions of Froth hard to follow; see the new-ish webpage, Impossible Geology, which houses a new blog and archives of some of older P.K.House blogs: Geologic Froth and others.

Geologize

Geology Blues

Geology Rocks

Geology and the World

geologygeek (offline) - now see lithics

Geology for Global Development (blogspot) - now at Geology for Global Development (EGU)

Geology Melange

Georneys - moved to Georneys (AGU)

geosteph

Geovertical

Green Gabbro (Sb)

Good Schist (offline) and Goodschist

Harmonic Tremors - now see Seismogenic Zone (which is inactive also)

Highly Allochthonous (offline at Sb) - moved to Highly Allochthonous (all-geo.org)
Highly Allochthonous Archive (blogspot) - see above

Hindered Settling (blogspot) - now at Hindered Settling (wordpress)

Hypotheses (wordpress & great resource) - now see Hypo-theses

Hydrofelicity

Hypocentre's Posterous (offline)

Igneous by choice Geoblog

In Terra Veritas

Indiana Meg

Johannes Lochmann

JY's 雜記 (offline)

Knowledge Flocs

Laelaps (Sb) - moved to Laelaps (Wired)

Landslides under Microscope

Liberty, Equality, and Geology (blogspot) now at Liberty, Equality, and Geology (wordpress)

Life as a geologist

Life is like a rock... - now reactivated!! - now inactivated again :(

Livin2dmax

Magma Cum Laude - moved to Magma Cum Laude (AGU)

Meanderings of a Mermaid - active but no geology

me and the laurentide ice sheet (offline) - moved to poorlysorted - erratically active

Meta-geologist - now at Metageologist (all-geo.org)

MiGeo

Mi tierra se mueve

Mountain Beltway - moved to Mountain Beltway (AGU)

Mountain Cat Geology

MSU Geology in the Field

My Geologic Adventures

NBMG - NV Bur Mines & Geology (offline)

Nig-eosyncline - now at Failed Rift

NOLÖGIC - (offline)

Not Necessarily Geology

NOVA Geoblog - now at Mountain Beltway (AGU)

NSF Geophysicists in Haiti - Jan - Feb 2010 only

Oblate Spheroid

Office of Redundancy Office

Olelog

...Or Something - now at Clastic Detritus (Wired) - now at Clastic Detritus (wordpress)

Ordinary High Water Mark

Paleowave (offline)

Pawn of the Pumice Castle

Pathological Geomorphology (offline) - now archived on Impossible Geology/Geopathology.

Petrified Wood

Phreatic Ramblings

Point Source - occasionally active!!

Pools and Riffles- now reactivated!! -- now inactive

Reel Geology: The Good, the Bad and...

Ripples in Sand

Rising to the Occasion - may be back!!

Roads of Stone

Rockin' the Himalayas

Rocks and water: a tectonics blog (offline?)

Rocks Math!

Rockscape Geology

Romania Rocks

Sandbian

Scenic Overflight

Sedimentary Basins and Petroleum Geology

Sedimentary Soliloquy

Seismogenic Zone

Sense of Shear (offline)

Shaking Earth

Shifting Paradigms

Sinuosity (offline)

Sismordia - Seismology at Concordia

Southern Exposure

Stories in Stone (blogspot) - now at Stories in Stone Blog (GeologyWriter.com)

Structural Geology

Stubborn as a Rock (offline)

Ten Million Years of Solitude (offline)

Terra Incognita (offline)

Terra Motus

The Great Winter of 2008-2009

The Ethical Palaeontologist (offline) - now at Stages of Succession (offline)

The Lost Geologist

The Transantarctic Mountains

The Volcanism Blog

Uncommon Vistas

Uncovered Earth (offline)

Underfoot

UnEarthed Tees' Geology News

Volcanic Activity Blog

Volcanista: a magmalicious blog

Volcanoclast

VolcanoSummer

WATCH FOR ROCKS – - – - – Travels of a Sharp-eyed Geologist - now at WATCHING FOR ROCKS – - – - – Travels of a Sharp-eyed Geologist

Water and Rocks...at the Same Time (blogspot) - now at Water and Rocks...at the Same Time (wordpress) - inactive

Watershed Hydrogeology Blog - now at Dr. Anne Jefferson's Watershed Hydrology Lab

Woodenlan(TM)

Zona de Cizalla (offline)

These blogs have been deleted from my sidebar (except when reactivated or sporadically active), and are now shown as one link: A List of Some Inactive GeoBlogs (this post). There are several more inactive geoblogs; you can find a complete list here, a list that includes sites that don't exist anymore and are just names. If you think you shouldn't be on this list, let me know. If you reactivate, you may reappear on the regular sidebar.

My sidebar does not link to all geoblogs.

The list, as continually updated, shows blogs inactive for about a year (or more). Last updated 8Dec2013

Monday, December 27, 2010

Like caterpillars, crawling or marching...

...northward out of or toward Mexico.

On Christmas Day, I went hunting for the source of the widely quoted description of the Basin and Range, starting with my easy-to-find reference in Bill Fiero's Geology of the Great Basin. He said that a long time ago a geologist had compared the mountain ranges of the Basin and Range to "dark fuzzy caterpillars crawling northward" [his words]. He didn't reference the geologist, so I got to wondering and went online. Well, I was already online, but I went farther, into that great Google machine, starting with "basin and range caterpillars," which got me the Wikipedia Basin and Range page and The Basin and Range Province (Coulter, 2005). Both pages state that it was Clarence Dutton who made the analogy, quoting him as saying "army of caterpillars marching toward Mexico" and "an army of caterpillars crawling northward out of Mexico," respectively. You'll immediately notice the double discord: marching v. crawling and toward v. out of.

I was inclined to go with the second quote, because it partly agreed with what Fiero had said, and because at least Coulter (2005) had given a reference, namely to King (1977). Going back to Google with basin and range "army of caterpillars" dutton, I found another reference to "an army of caterpillars crawling northward out of Mexico" by Mac and others (1998), who again cited King (1977), with Dutton being the quotee; and I also found this article (Jensen and Platts, 1990), which quotes Dutton (1880) as saying "army of caterpillars marching to Mexico," reinforcing the quote confusion, but providing the alleged source: Dutton (1880).

So, hence to Dutton's 1880 tome, Geology of the high plateaus of Utah, which is searchable online by various methods, including visual scanning. The quote, if present in that volume in any form, would have to be hidden on a map included in the Atlas (which I also viewed and eliminated), or in the footnotes, many of which I scanned. Searching for "caterpillars" or "Mexico" does not yield the quote; searching for all occurrences of "north" does not yield the quote. I didn't try all occurrences of "out of" or "toward," but did scan all seemingly relevant chapters and sections more than once without results. The problem with search methods other than reading or visual scanning, is that the original is old, so some words don't search properly or have been changed by the various methods of acquisition (e.g., digital scanning) to other words or nonsense words. Also, a word like northward can be broken at the end of a line into "north-" and followed in the next line by "ward." The quote might still be in there somewhere, but I doubt it.

Then, tyring to get some help via Twitter, I was led by @rschott to the above picture, which is from Dante's View at Death Valley National Park. The sign quotes Dutton (1880) as saying, "...like an army of caterpillars crawling toward Mexico...." Darn, there for a minute I thought the caterpillars crawled when going north, and marched when going south!

Ron Schott also found an old reference to the quote, wherein Keyes (1920) said that Dutton "likens [the ranges] on the map to an army of caterpillars crawling northward out of Old Mexico." This is the oldest reference (so far), perhaps giving credence to the northward crawling aspect of the alleged Basin and Range quote. Additionally, at least one reference (Udall, 1998) has Dutton "quipping," suggesting that Dutton might have been speaking at a meeting rather than writing a report.

Another tidbit in this intensive reference hunt: I found one endnote (in Goin and Starrs, 2005) that states:
"army of caterpillars" is without a doubt Clarence Dutton's comment, but exact attribution is impossible – although everyone knows he wrote or said it, chapter and verse are undocumented in our experience, but it is quoted by John McPhee in Basin and Range (1981).
I couldn't find the quote or a reference to Dutton in Basin and Range.
Basins and ranges in central Nevada

And then things got interesting.

This search led to a more detailed quote from Dutton: "composed of many short, abrupt ranges looking upon the map like an army of caterpillars crawling northward. At length the army divides into two columns...." I couldn't, however, search farther in that book (Anderson, 1977), or find where Dutton said that. Later, on Boxing Day, I used this search confining the timing to 1879 to 1921, and found this long reference to Dutton's description of the desert mountains or arid ranges of the west (Keyes, 1909), though it isn't explicitly a quote:
Upon the map Dutton has likened them to an army of caterpillars crawling northward out of Mexico, dividing as it enters the United States, the main body turning westward and then northward again until it passes into the British possessions.
I was pretty sure at this point that we had narrowed it down to, more or less, "an army of caterpillars crawling northward out of Mexico," but I still couldn't find the reference!

I then went a little farther, using this search to reveal even more of the Dutton quote, still with no viewable reference (Anderson, 1977):
"...composed of many short abrupt ranges looking upon the map like an army of caterpillars crawling northward. At length the army divides into two columns, one marching northwest, the other north-north east."
Anderson (1977) then goes on to say, "Hence the Great Basin's ranges, and the Rockies...," implying that the quote refers to the entire west, not just the Basin and Range.

By this time, I was ready to finish up this blog post and move on, so I grabbed another view of the west from Google Earth...
And then, late in the afternoon, another link came in from Twitter, this time from @microecos, who blogs here. It's the full and entire quote, with the source! Dutton (1886) says:
The great belt of Cordilleras coming up through Mexico and crossing into United States territory is depicted as being composed of many short, abrupt ranges or ridges, looking upon the map like an army of caterpillars crawling northward. At length, about 150 miles north of the Mexican boundary, this army divides into two columns, one marching northwest, the other north-northeast The former branch becomes the system of mountain ridges spread over the southern and western portions of Arizona, the whole of Nevada and the western portion of Utah and extending into Oregon and Idaho.
What he goes on to say from there, makes it clear that the western army going to the northwest (to begin with) is the Basin and Range of Arizona, Nevada, Utah, Oregon, and Idaho, and the eastern army, going to the north-northeast (to begin with) is the Rocky Mountains.

Check it out for yourself, right here!

How many times has Dutton been misquoted? Not sure, but I'd say tens of times—or more! I own at least two such misquotes, myself (the caterpillars crawling or marching to or toward Mexico rather than crawling northward). Surprisingly, the misquoting began as early as 1915!

Some References:
Anderson, R.S., 1977, A biography of Clarence Edward Dutton (1841-1912), nineteenth century geologist and geographer: Stanford University, 252 pp.

Coulter, Poppy, 2005, The Basin and Range Province: Volcanoes of the Eastern Sierra Nevada,: Geology and Natural Heritage of the Long Valley Caldera, at Indiana University Geological Sciences (a field course website).

Dutton, C.E., 1880, Geology of the high plateaus of Utah: U.S. Geographical and Geological Survey of the Rocky Mountain Region, vol. 32, 307 pp, with Atlas.

Review of Dutton's 1880 monograph at Magma Cum Laude

Dutton, C.E., 1886, Mount Taylor and the Zuni Plateau, p. 105-198 in Volume III of Report of the Secretary of the Interior; being part of the Message and Documents Communicated to the Two Houses of Congress at the Beginning of the First Session of the Forty Ninth Congress in Five Volumes: Washington, Government Printing Office.

Fiero, Bill, 1986, Geology of the Great Basin: University of Nevada Press, 198 pp.

Goin, Peter, and Starrs, P.F., 2005, Black Rock, Volume 2004: University of Nevada Press, 273 pp.

Jensen, S.E., and Platts, W.S., 1990, Restoration of degraded riverine/riparian habitat in the Great Basin and Snake River Regions, p. 367-404 in J.A. Kusler and M.E. Kentula (eds.) Wetland Creation and Restoration: The Status of the Science. Island Press, Washington, D.C. 591 pp.

Keyes, C.R., 1909, Lineaments of the desert: Popular Science Monthly, v. 74, p. 19-30.

Keyes, Charles, 1920, Paleozoic Diastrophics of the Northern Mexican Tableland: The Journal of Geology, vol. 28, no. 1, p. 75-83.

King, P.B., 1977, The Evolution of North America: Princeton University Press, 216 pp.

Mac, M. J., Opler, P. A., Puckett Haecker, C. E., and Doran, P. D., 1998, Great Basin—Mojave Desert Region in Status and trends of the nation’s biological resources Vol. 2: U.S. Department of the Interior, U.S. Geological Survey, Reston, VA, p. 437-964.

McPhee, John, 1981, Basin and Range: Farrar, Straus, Giroux, 215 pp.

Rice, W.N., Adams, F.D., Coleman, A.P., Walcott, C.D., Lindgren, Waldemar, Ransome, F.L., and Matthew, W.D., 1915, Problems of American geology: a series of lectures dealing with some of the problems of the Canadian shield and of the Cordilleras: Yale University Press, 505 pp.

Udall, S.L., 1998, The myths of August: a personal exploration of our tragic Cold War affair with the atom: Rutgers University Press, 412 pp.

A Few Google Book Searches:
clarence dutton caterpillars
dutton caterpillars crawling (1879-1921)
dutton caterpillars crawling northward divides northeast
abrupt ranges looking upon the map like an army of caterpillars

Saturday, December 25, 2010

Xmas Greetings from Nevada!

Christmas tree inside Middlegate Station, along Highway 50 in central Nevada—that "loneliest highway" and also the Lincoln Highway.
Decorated antlers.
Decorated six-pack condiment holder.
The view from inside, with decorations.

Decorations were spotted earlier this month, when MOH and I were at Middlegate to do some exploration and to generally get away from it all.

Happy Holidays to all, wherever you may be!

Friday, December 24, 2010

Geology on the Road: Breccia with Flow-Banded Rhyolite

The other day, we looked at some flow-banded rhyolite, beginning at the vertical fractures near the fence on the left side of this photo, and ending on top of the knobby hill overlooking the corral. Warning: we won't see much flow banding, if any, today, but its still there. We will, however, find out why we stopped here while on our way to somewhere else. For scale, the log forming the top of the corral fence is about 5.5 feet above the ground. Location: near Middlegate and The Shoe Tree, just north of Highway 50 (Google Maps, Google Maps Street View, MSRMaps).
This mass of breccia in the center of the exposure immediately caught our attention, but we stopped to examine the caves, and only after stopping noticed the breccia. Note the bird nest, possibly an owl's, on the upper flat surface. And note the several caves, with MOH for scale climbing up to check one of them out. You'll also want to note that about waist high on MOH, and over to the right just before the rightmost vertical fracture, you can see a large dark patch or two. These are breccia fragments.
The inside of the upper cave: a good place to find pack-rat middens and small bones.
The largest, uppermost breccia fragment is about 2.5 feet in length and perhaps a foot or more wide. It appears to be surrounded by small fragments, with another large fragment below it to the left. I didn't try chimneying up the fracture to check them out in more detail, so we'll have to rely on this crude description.
In the main exposure to the right of the caves, large breccia fragments are within reach of even short people like myself. Besides the large, dark brown fragments to the right, you can see several small fragments near my hand. The breccia fragments consist of angular to subrounded pieces of rhyolite, which are set in a matrix of smaller fragments.
This large fragment shows what looks like volcanic flow banding or hydrothermal streaming around the right side of the fragment. I suspect that more than one type of brecciation might be exhibited at this outcrop. Candidates include primary volcanic brecciation, brecciation associated with caldera formation, and tectonic brecciation associated with faulting. Another candidate is hydrothermal brecciation.
Here's another example of what the matrix looks like, closer to that first exposure of flow-banded rhyolite from the other day, and visible as a large bright orange spot near the fence on the left side of today's first photo. At first glance, this pale to dark yellow orange to dark yellow brown mass looks like a clast or breccia fragment, but I think what we're seeing is a weathering phenomena, with a piece of the outer, dark brown weathering rind broken off, exposing relatively fresh rock beneath. We can see some light gray veinlets of silica shooting vertically through the yellow orange mass, and there are hints of large fragments cut by small veinlets. The next picture shows a portion of the rock to the right of the middle silica veinlet.
The rhyolite is fractured, possibly brecciated or at least crackled, and shows moderate iron-oxides, mostly goethite and jarosite.
A closer view shows a lot of very fine-grained to microcrystalline light gray silica that forms a matrix around tiny breccia fragments, or has at least replaced an earlier volcanic matrix. Possibly some of the brecciation seen in this exposure is hydrothermal. I recommend petrographic work to get down to the nitty gritty and to really understand what we're seeing.
From the top of the knob, we see the main road north into the central part of the Clan Alpine Mountains. We'll drive up there later, and make a sharp right turn in about a half mile, not far past the second little bend.
And lo, there's Fairview Peak off to the southwest, visible through two knobs of lichen-covered flow-banded rhyolite and rhyolite breccia. Middlegate Station is behind the knob on the right. Will we make it beyond Middlegate Station to Fairview Peak?

Thursday, December 23, 2010

Some Alcan Mileage Links

While we're experiencing being semi-snowed in, I'm going to post a few Alcan links, in case any of you have been thinking about driving that highway this winter. (I've been thinking of it, but decided that I don't have enough time right now.)

Alaska Highway - at Wikipedia

Alaska Highway or Alcan? - some history

Alaska Highway 97 - towns and more info at BritishColumbia.com

Alaska Highway Road Log - road log by miles and kilos

Bell's Travel Guides: Alaska Highway - another road log

MilebyMile.com - photos along the Alaska Highway

Wednesday, December 22, 2010

Snow Days = White Christmas

Yes, we'll be having a white Christmas, thanks in part to the recent (and now tapering) Pineapple Express. Image is from NOAA, the evening of the 19th (2:30 Dec 20 UTC).
Here's what it looked like yesterday in front of our little house...
...and here's what it looked like this morning.
The Prius yesterday...
...the Prius this morning, slowly getting buried deeper and deeper.
We don't have all that much room to pile up snow when we shovel it, so we use a wheel barrow to haul the snow uphill out of our driveway, down the street where it can be piled out of everyone's way.

Note the conspicuous absence of my truck in these photos. It's parked on the street below because it wasn't possible to get it up the hill yesterday, though by the end of the day it probably would have been possible. It is, however, safe from becoming snowed in like the Prius, so we're just leaving it there for the nonce. If we do laundry today or tomorrow, we may have to haul our baskets down to the truck with MOH's snow sled, the one he uses to carry extra gear when snow camping.
Snow on our roof, as of this morning. Yesterday, after two days of snowfall amounting to about a foot per day, I measured 14 inches of compacted snow on the low roof behind our garden.
Here, MOH is measuring the snow on our rooftop. L-square height is 24 inches. His measurement of 17 inches agrees with my behind-the-garden measurement, also of 17 inches. Snow depth varies considerably from place to place, and the 2 feet of Sierra Cement that fell the first two days (after a day of rain) compacted immensely.
Another shot of the Prius.
Inside, I have found the view out my window to be fascinating: ice from icicles has melded with snow on branches.
Unfortunately, these shots can only be taken through the non-removable window screen.

Why does it snow?
More on the Pineapple Express, called an "Atmospheric River" at the WunderBlog.

Tuesday, December 21, 2010

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!

Sunday, December 19, 2010

My 2010 Year of Traveling Meme

This traveling meme began last year, and was started by Alice at Sciencewomen. Others who did it in 2010 include Magma Cum Laude, NOVA Geoblog, Geotripper Part 1 and Part 2, and Geology Happens. This has been a fairly impromptu meme, with no detailed rules, and everyone should consider themselves tagged.

January: First off, I drove to Salt Lake City for a blogger meetup with Hgg. Later, I went to Elko for a meeting and to the lake to check out the snow.

Snow-covered valley in Utah with distant ice-fog.

February: MOH and I went to Great Basin National Park, which I've blogged about incessantly over these last couple years. I also made one roadtrip through Nevada, although I'm not sure why.
Ice near Sacramento Pass on the way to Wheeler Peak

March: In early March, I drove across the wet salt flats of Utah...
...and ended up on the icy mud flats of Alaska. In Alaska, we saw wildlife, a river (an icy river), a glacier (or not), a lodge with good beers, and more snow. I had flown north to see the Iditarod, but we ended up watching it on TV instead of braving the downtown cold.

April: Work, nothing else.

May: MOH and I went to Wheeler Peak, and later in the month we attempted Spencer's Hot Spring (too crowded), stayed in Austin, hiked to the Cold Springs Pony Express Station (not yet blogged), and went to the lake. I drove across Nevada to go to the GSN Gold Symposium, and went on two field trips, including a stop at Goldfield.
Lupines and ash-flow tuff on the trail to the Cold Springs Pony Express Station.

June: MOH and I came back from our late May trip to the lake, and then I drove to Big Smoky Valley, stopping briefly in Kingston, Carver's Station, Manhattan, and Belmont. We stayed once again in Austin, and went to Wheeler Peak at the end of the month.
Spectacular lenticular cloud in Big Smoky Valley, east side of the Toiyabe Range.

July: The biggest trip of the year for both MOH and I, was our trip to central Oregon via a brewery, Jarbidge, Baker City, and John Day Fossil Beds. While there, we saw lots of geology. We then returned via the Winnemucca-to-the-Sea Highway, a story which is not entirely complete.
Mt. Jefferson as seen from the Dee Wright Observatory

August: Work picked up again in August, so I didn't travel much. I did, however, manage to make it down to that Nevada hub, Tonopah. Over the course of three days, I crammed in lots backroad driving while looking at various geological features...
The Crater, in Clayton Valley north of Silver Peak.

...wandering around a couple old stomping grounds...
A southern pass into Fish Lake Valley,
with Mount Pinchot (13,494 feet, 4113 meters) of the Sierra Nevada in the distance.

...and dropping in on the infamous Silver Peak.
The Miner's Inn of Silver Peak, now defunct and rather bland looking. Was once the home of Alice's Restaurant, where you could, indeed, get anything you wanted.

As you may remember, I returned from the Tonopah area on one of the dustiest roads in Nevada.

September: After going to Elko for a meeting, I drove through Ruby Valley (MSR Maps), then took a long dirt road through Long Valley.
Ruby Lake NWR in the fall.

October: I went on the GSN fall field trip (a very dusty and slow affair due to an inexperienced bus driver who didn't like dirt roads or mines); then MOH and I took our famed Ophir Canyon route to Middlegate and beyond, returning via Pyramid Lake and Austin, NV.
Old building in Austin, NV.

November: Work.

December: While I was returning from an unexpected trip to the lake, MOH was making his way through central Nevada to another destination, so we decided to meet at Middlegate Station, where we spent two nights. We attended one of their twice monthly (or every other week) Prime Rib feeds, which I highly recommend. We banged around on some rocks, looked for fossils, and walked around on the fault scarps from the 1954 earthquake at Fairview Peak, which wasn't very photogenic because of heavy overcast. Central Nevada roads, even in the lowlands, are no longer recommended because of mud, snow, and continued storms. The central Nevada lowlands in question are at about 4000 to 5000 feet in elevation (MSR Maps). Low lowlands below 4000 feet are muddy to questionable.
The 1954 fault scarp is that irregular line cutting across the face of the mountain, generally below bedrock and often near the top of the alluvial fan. The scarp is by no means linear, and more than one can be seen in places. (Photo taken at about 6500 feet on the east side of Fairview Peak from a muddy road.)

MOH and I have already been to Wheeler Peak once this month, where the slopes were partly hidden by slowly lifting ice fog.
Wheeler Peak shrouded by ice fog and ice clouds.

And the year isn't over yet!
Where have you been?

2010 Participants:
The Musings of a Life-Long Scholar
Geotripper
Geotripper Postscript
VWXYNot?
Mountain Beltway
Andrew's Geology Blog
Maitri's VatulBlog
Geology Happens
Magma Cum Laude
Chris Rowan at Highly Allochthonous
Point Source
En Tequila Es Verdad
Anne Jefferson at Highly Allochthonous
Georneys
Liberty, Equality, and Geology

Tuesday, December 14, 2010

Geology on the Road: Flow-Banded Rhyolite with Breccia

This hydrothermally altered flow-banded rhyolite, with thin layers or bands dipping gently away from us to the east, is in the eastern arm of the Clan Alpine Range of central Nevada, within walking distance of Highway 50 and not far from The Shoe Tree. To get there, from Highway 50 just west of The Shoe Tree, turn north at the sign that says Bench Creek Ranch 13 miles. The dark brown jutting outcrops showing cavernous weathering are immediately to your right as you pass through a corral, just east of the large bend in the graveled road (Google Maps, Street View from Highway 50). The main graveled road will take you farther into the Clan Alpine Range and to Bench Creek Ranch; side roads lead off in many interesting directions. This locality is about 500 meters west of Middlegate the geographic place (MSR Maps).

For more on flow banding, see this Short Primer at the relatively new geoblog, Chaotically Flow-Banded.
Looking upward from my shoe (which I didn't leave at The Shoe Tree), you'll see an irregular contact between the lower, whitish to pale orange flow-banded rhyolite and a mass of dark, iron-oxide-stained rhyolite breccia. The contact is marked by green grass. Above the breccia near the top of the photo, we get back into light brown flow-banded rhyolite, this time with flow foliation dipping off to the southwest.
The contact between the lower flow-banded rhyolite and the rhyolite breccia is irregular but generally vertical, seen best when looking along the contact toward the north, where it runs into the near vertical crack on the right side of this photo. The vertical nature of the contact suggests a possible fault, as does the presence of breccia. We need to remember, however, that volcanic rocks can do weird things — they can show strange and unexpected fabrics — because they are created in the tumultuous environment of... volcanoes.

In this particular instance, we happen to be near the southern margin of the large volcano-tectonic trough that runs east-southeast from the Stillwater Range, through the Clan Alpine Range, through the Desatoya Mountains, and into the Shoshone Mountains. The trough is about 40 km wide and 100 km long, although it has been extended somewhat by Basin and Range faulting and wasn't originally that long. This southernmost of two volcano-tectonic troughs in central Nevada formed in the late Oligocene to early Miocene, with the likely generation of several large or very large overlapping calderas (likely VEI 7 to 8). Volcanic rocks in the Clan Alpine Range erupted in two pulses between 29 and 30 and 24 to 25 million years ago (Burke and McKee, 1979). A better place to view the southern margin of this volcano-tectonic trough would be south of Eastgate in a western arm of the Desatoya Mountains and south of Highway 50 in the main part of the Desatoya Mountains.

The breccia could be both volcanic and tectonic in origin, and I suspect that at least some of it is volcanic. Fragments range in size from a less than a couple centimeters to over a meter wide.
MOH and I were out exploring, already wandering off our intended path, so we took the time to climb (I mean climb, not hike) to the top of the brownish hills. We found more volcanic breccia and a lot of flow-banded rhyolite. Here the lichen-covered flow banding is dipping to the southwest.
And here in this small cliff, the banding is entirely vertical, possibly giving way upward to brecciated rhyolite (cheat grass in the lower left for scale).

References:
Burke, D.B., and McKee, E.H., 1979, Mid-Cenozoic volcano-tectonic troughs in central Nevada: Geological Society of America Bulletin, v. 90, p. 181-184.

Steward, J.H., and Carlson, J.E., 1976, Cenozoic rocks of Nevada--Four maps and brief description of distribution, lithology, age, and centers of volcanism: Nevada Bureau of Mines and Geology Map 52.