Sunday, March 29, 2009

Honey Lake Update: Dust, Rain, and Water

While out driving around last week, I stopped at the Honey Lake Rest Area on Highway 395 between Reno and Susanville, and watched a dust storm, with scattered dust devils, on the Honey Lake playa. Honey Lake is shown on this map and photos as a lake, but it isn't much of a lake these days.
It was a dark and stormy day, and one particular dust storm arose, grew, whirled a bit, and dissipated while I watched. The photos of this storm were taken looking a little north of east from the rest area.
The Skeddadle and Amedee Mountains form the backdrop for this particular dust storm.
Here, the dust storm does a bit of whirling, forming a wide-diameter dust devil, prior to dissipating.
While the dust storm gets smaller, a vaguely funnel-shaped cloud forms above it. This cloud is probably not a funnel cloud, though I have seen small funnel clouds above large dust devils.
Now the dust storm is getting thinner and thinner, dwindling while I stand in the rain, getting wetter and wetter.
Meanwhile, a bit to the south, some classic dust devils arise in the desert mirage.
My favorite mirage-based dust devil of the day.
cloud1 The clouds above the larger dust storm formed interesting shapes, especially as the dust storm was winding down. Here are a couple enlargements of the cloud shapes.
cloud2
raven On the next day, the storm - wind and rain - was mostly gone, the playa was wetter, and vultures flew back and forth in front of me.
A little farther south, in the southwest arm of Honey Lake, I spotted some water in the lake (enlarge and look closely!).
The water was south of The Island, almost lapping up against a landform I sometimes call "the bluff." I'm always a bit happier when I can spot some water in Honey Lake.

Friday, March 27, 2009

Spring Snow Squall in Central Nevada

And I drive through it!

Snow squalls were cruising through central Nevada last week when I was coming back from the lake. Snow in springtime is common in this high desert to steppe environment, and snow in summer - at least on the tops of mountains - was fairly common when I started field work out here in the late 1970's. The snow, the sun coming through the clouds, and the cloud shapes and shadows all make for interesting drives in the mostly wide-open countryside.

trees Here, as I approach Middlegate (the place) from the west, the willow trees in Eastgate Wash are lit by sun shining beneath clouds behind me. Darkness and glowing mountains loom around the corner. (Also see "A little more about the geography" at the end of this post for more about the Middlegate region.)
mirage Highway 50 turns to head in a northerly direction after passing through Middlegate (the place), and heads for a moment or two right at this snowy part of the Desatoya Mountains. The bright reflection of sun from the snow creates mirage on the road ahead of me.
glow Ooh, more glowing mountains, this time near Cold Springs, which is a small outpost that offers gas, food, lodging, and RV hookups. The slanting light-dark contact of foreground and background shows a typical slope at the foot of desert mountains, the kind of slope that is often composed of a combination of alluvial fan and pediment (also here and here).
clouds Yellowish sunlight peeps through from the west beneath dark clouds.
pediment Another view of the slanting slope at the western foot of the Desatoya Mountains, probably a pediment with alluvial fan cover.
ranch As I round the next corner and start heading east toward Austin, snow starts falling in waves or patches, and it nearly obliterates the view of this ranch just north of Highway 50 in Edwards Creek Valley.
large clouds Now I'm heading in an easterly direction toward New Pass, a canyon running between the north end of the Desatoya Mountains and the south end of the New Pass Range, but I can't see the mountains!
snowy road And here's why: it's snowing in New Pass, and visibility has dropped again.
snow In fact, here visibility gets worse, although the snow on the road is minimal.
snowy mountains Finally, I come through this particular snow squall and can see Reese River Valley and the Toiyabe Range beyond. The small town of Austin, Nevada, is just off the picture to the left (north) in the Toiyabe Range.

This post is a submission for the Third Carnival of the Arid at Coyote Crossing.

Thursday, March 26, 2009

The Geologist: Fully Equipped for the Field

No, I'm not going to add a picture here, although The Lost Geologist did; his picture details everything he carries when fully field ready. Maybe I'll add a photo of myself later, but right now my field gear is strewn all around my bedroom and all through the front and back of my truck. That's often what happens when I come in from the field. So I'll more or less follow checklists, which - for this impromptu geo-meme - can be found at Geotripper and Johannes Lochman. Update: I didn't see Kim's entry at All of My Faults are Stress Related when I wrote this. And now, Hypocentre has one up, also.

Hair: Mine is pulled back and up in a clip, and always completely hidden by a sunhat or baseball cap. I gave up on any kind of ponytail a long time ago.

Sunburned Peeling Nose: I generally avoid this one, with sunscreen rated 35 to 50, if at all possible. I already had way too much sun exposure when growing up in the baby-oil suntan lotion days.

Beard: Thankfully, none at all. It would look strange with my female body!

T-shirt and Logo: When wearing T-shirts instead of long-sleeve, sun-proof, breathable shirts (or winter gear and layers), my T-shirts are usually devoid of logos anymore and often have pockets. Pockets are so essential.

Vest: I wear a vest, often a beige Filson (or a bright orange one for hunting season), but more recently a larger, fluorescent orange safety vest, like this one.

Things in the Vest: For me, the vest is designed to carry almost everything that I carry, because I try to avoid having a backpack (only if sampling big time). The back vest pocket (or two), can carry as many as four or five 5-pound rock samples. The back pocket is also a handy place to put hand samples, the rock hammer, and clothing taken off when de-layering in cool-cold-rainy-snowy weather. That's also where I put my water bottle and sometimes my lunch. A few sample bags belong inside the back pocket.

Front inside pockets hold my Brunton compass, any safety papers I need in a plastic baggie, toilet paper in another baggie, any cheat sheets I think I need, extra map scales, my field book, GPS, sample book if needed, flagging, topofil thread and hip chain if needed, extra markers, extra GPS and digital camera batteries, and sunscreen.

Front outside pockets hold my acid bottle in its leather case, protein bars, and my digital camera (or does that go on the inside?). Because my acid bottle is in a pocket, my vest is sometimes adorned by duct tape where acid has eaten through the vest material. Acid bottle and sunscreen have to be kept away from any paper like maps and field book, and from batteries and food. Sunscreen and acid have to be kept away from GPS and digital camera, as does any water or other liquids.

Upper left pockets hold pens, pencils, a few colored pencils, a couple markers, and map scales. I'm currently putting my hand lens and magnet, which are on a nylon cord and are designed to hang from my neck, into the upper right pocket, but I may remove the velcro that closes that pocket - then I will be able to hang the lens and magnet from my neck, where they will rest in that de-velcroed pocket while hanging.

I've probably left a couple things out; one usually figures those things out after the first day or two.

Belt and Buckle: I wear a sturdy, nylon webbing belt, and try to avoid carrying anything on the belt, including hammer, acid bottle, or Brunton. Instead, the hammer is in my hand or in the large back pocket of my vest; the acid bottle is in one particular front vest pocket; and the Brunton is in some other particular front pocket. The only thing I attach is my pocket knife, which is tied to a belt loop by an extra boot lace. It's attached to me that way because I've left it behind after lunch way too many times.

Pockets: Keys, ear plugs, sun-proof chapstick, maybe some lysine ointment in case I develop sun-caused fever blisters, maybe my data stick if I've been to the office - these all go in the two front pockets, the keys in a zipped pocket if I have one. Any motel keycard I happen to have will be in a zipped pocket or in my truck with my wallet, well hidden. Sometimes my camera will fit into a front pocket. My cell phone goes in a zipped pocket on the side, down above the knees - or in the field vest in a zipped or velcroed pocket.

With all the pockets available on pants and vest, I have managed to take and carry several samples after running out of sample bags (or once when I forgot them). One has to be careful when sampling this way to make sure there is no contamination already present in the pockets (ha!), to label the samples somehow, and to get a large enough sample size. This method of sampling is not recommended, and is usually only good for a few, small samples.

Rock Hammer: As Geotripper mentioned, a rock hammer is useful for things besides whaling away at rocks and outcrops. For one thing, hammers are good for hammer-throwing contests. Many kinds of contests have been devised, and new ones can be invented if the old standard ones get boring. Be sure not to hit the back of one's head when winding up for a good hammer throw (this happened in one particular throwing contest that took place the western Mojave north of Tehachapi).

Hammers are also good for defending oneself: from rabid bobcats, for example, and from coyotes (I thought about it once when I looked up and three were staring at me from across a 20-foot-wide sand wash), and also from potentially bad-ass people, who are sometimes found in locations south of the Garlock fault or anywhere in the vicinity of the Panamint Range.

I sometimes carry a 2.5 pound sledge hammer with a long wooden handle that doubles as a walking stick on steep sidehills. It's also good for aiding with balance.

Hands: I will carry my rock hammer, map case or large map board, and GPS. A map case will fit in the back Filson or vest pocket; a hammer will fit there, also. I look at my GPS almost constantly when mapping.

Legs: I'm with Johannes on this one. I have rarely worn shorts in the field - to avoid sun and scratchy or thorny bushes - so my legs are not tan, and they are hidden under pants. Are they muscular? Who knows?

Pants: These are the things that cover the legs, and which add pockets to the list of many pockets above. I wear loose cotton jeans with a carpenter or painter style for extra pockets - or, more recently, nylon pants with extra pockets. These are thin, light-colored pants which can double as exterior winter pants to keep out rain or snow when used with long johns for warmth. If it's too cold, overpants and lined pants are required, sometimes diminishing the number of available pockets. But winter is a special case where staying warm trumps number of pockets or how much one can carry.

Shoelaces: These are indeed sometimes knotted to preserve their useful life, and also because I can never remember what length to buy.

Socks: It's nice if one's socks match the rest of one's outfit, but if not wearing shorts, matching becomes non-critical. Sometimes thin under socks are required.

Boots: Recently, my best (most comfortable) pair of field boots has been an ugly black pair, a composite safety toe variety, with pseudo-Vibram soles.

Ironclad Bladders: "For 300 mile drives to geologic localities without stops," per Geotripper. I have met a few geologists with "itty-bitty-bladders" who were always needing stops out in the middle of nowhere, where the largest cover is the truck. Thus developed a long-standing rule: men use the front of the truck, women use the back, and everyone has to get out of the truck or van and go to their places. That's so all men are in front of all truck mirrors. I have met a few men who would prefer that I walk miles to find cover rather than them get in front of the truck while I use the back of the truck as a potty - but these men have, thankfully, been rare, and I never listen to them. It can seem a little uncomfortable ordering one's boss to the front of the truck, but - hey, you do what you gotta do!

Another characteristic is required for one's bladder in desert or other non-cover areas: speed. Speed is needed when the only place to stop is the side of a straight stretch of dirt or paved road. Exceptional speed is needed when the road curves and you can't see around the curve.

Brunton Compass: Yes - see above. These can be used on rare occasions for signaling to wayward helicopters, but don't expect them to see you. These can also be used for checking into mine adits to see how far into the hill they go.

Eyes: Sunglasses are often worn; ones that change from light to dark can be useful. Always be on the look out for - everything.

Brain: "Dehydrated, half-baked, freeze-dried, poisoned, but always plotting the next trip," also per Geotripper. Indeed. And sometimes thermally altered by too much sun or too much beer.

Hat: Worn to protect said brain - see "Hair" above.

Backpack: When I carry a backpack, in addition to all of the above things, I will for sure have an emergency kit including snake-bite kit, more water, toilet paper, lunch stuff, lots of extra sample bags, moleskin, extra glasses, and waterproof matches wrapped in ziplock baggies.

My backpack often has other miscellany leftover from hiking trips; I don't always know what these things are or when I decided they were useful. For example, spare change for phones and dollars for cabs are rarely needed. Whereas I have seen pay phones in the middle of nowhere, these are getting rarer and rarer: a phone booth once located near Cima Dome, CA, was taken out in 2000 because it became too popular in the 1990's. Another in-the-middle-of-nowhere pay phone still exists, as far as I know, to the east. I used this other pay phone as early as 1983, before Cima Dome became popular and inspired a movie.

As far as cabs go (ha!), I have seen them deliver people down miles of terrible dirt roads to places as far away from a city as The Pyramid on the east side of Pyramid Lake; however, if you need a cab when already out in the middle of nowhere because your truck broke down or because your field partner forgot to meet you at the end of the day, one will rarely drive by on whatever dirt road or sand wash you happen to be stuck in. In fact, I've never seen a random cab go by anywhere out there.

The Short Geologist at Accidental Remediation has numerous posts relating to field gear of all kinds, including clothing and tools for your field vehicle.

Wednesday, March 25, 2009

Wedge #16: A Bit on GPS Mapping

This post is a submission to the March Accretionary Wedge, being hosted by Kenneth Clark at the Office of Redundancy Office, which is on recent geologic, geological, or scientific advancements.

Over the years there have been numerous advancements that have affected my interests and the way I do my work. Some of these have related directly to my geological interests (discovery and recognition of Carlin-type deposits, prior to my move to Nevada, would be one example). Others have related more to the way we understand geology in a broad sense, for example plate tectonics, which is specifically off-limits for this Wedge. The changes in computer technology over my entire career so far would be an example of advancements that have affected the way I do my work and the way we all do geology in general - from dropping cards in card-readers full of Fortran and sending the program to the mainframe, to our first moves into personal computers with early IBM's, Compaqs, and Macs, to the present use of various high-speed (until tomorrow) laptops and mobile computing devices.

Recently, the use of GPS devices has directly affected the way I do mapping. Prior to 2005 or 2006, I mapped solely on paper with no electronic support. I preferred enlarged air-photo base maps, and transferred my geology to topography using a triangle method that was involved and time-consuming. My recent forays into using a GPS while mapping have rapidly evolved to where a GPS unit is required.

GPS use while mapping and sampling can increase the amount of work one person can do tremendously, and it can also increase the detail of the work, depending on scale and time. When sampling, it's fairly easy to take a reading, take a sample, rewrite the GPS waypoint label with the sample number, and move on to the next sample. The location is more precise than the former dot on the map, and maps can be plotted directly from raw or fairly raw GPS data at any scale. It's probably best practice to still plot the sample location on a map while in the field, as a kind of backup, and a tertiary backup would be to write down the GPS northing and easting in your field book. For fast work, though, the second step is sometimes done in the afternoon or evening, and the third step is often skipped entirely.

I still write down many GPS waypoint labels or numbers in my field book, with attached notes that include the azimuth and angle information of structures, bedding, and other orientations, along with any notes such as locations of digital photos. I rarely write down the GPS readings - the northings and eastings - but for backup purposes, as mentioned above, these data would be useful if the GPS totally failed en route to the motel or office.

I recently discovered how easy outcrop mapping can be when using a GPS. An outcrop map is moderately common in exploration and mining. An outcrop map can be made on any type base map, including an air-photo base, a topographic base, or a grid base. With a GPS, one can walk around the area of outcrop taking points every so often, the frequency of point-taking depending on scale of the map. Using a grid sheet, one can then plot up the points and draw in the outcrop. One can then add in bedding, structure, contacts, and other information on the mapped-in outcrops, taking GPS readings for all orientation measurements. GPS waypoint numbers or labels are easily converted to actual azimuth and angle readings - either immediately or later - with an initial letter symbol defining the point number as bedding, fault, joint, cleavage, fold axis, or other. A GPS point number or label could be B07525, indicating a bedding strike of 075 or N75E, with a dip of 25 degrees to the SE. One uses a right-hand or left-hand rule for determining strike and dip, and you have to be sure everyone knows what you mean by right-hand or left-hand (and see the comments).

What I found is that this method requires GPS and grid-sheet only; no other base map besides the grid sheet is required: you don't need to have any grid-lines marked on the ground, you don't need to have any air-photos, and you don't need to have any topographic maps in hand. The outcrops as plotted from GPS data onto the grid sheet become the base map. It can be useful to have an air-photo or topographic map to look at or examine while in the field; these are not needed, except for some kinds of interpretation, and mapping goes much faster without them.

I do feel lost when getting started with this method, however, probably because I still miss topo lines or air-photo trees. I stare at the grid sheet of two dimensions while the large three-dimensional world looms all around me. It's a little like trying to write on a fresh, white sheet of paper, which gives me a form of writers block I elude by using yellow paper, or by typing as fast as possible on a computer. If you want to avoid white-paper syndrome while starting to map on a faintly blue-lined white sheet of grid paper, plot up some points as fast as possible - or, better yet, spill some coffee or dirt across your map.

UPDATE: This Wedge was not published, hence it isn't #16 as stated above.

Sunday, March 22, 2009

Update from the Lake: Snow!

I thought I'd report that at least the grape hyacinths would already be blooming...
...but it turns out that it's about two weeks or more too early for them.
And daffodils will bloom in May. Some are popping their heads up - barely - many are buried under deep snow in the backyard.

Thursday, March 19, 2009

Geo-Beers: Sleeping Lady Brewery

Continuing on with The Sleeping Lady theme of our most recent Where in the West contest, Sleeping Lady Brewery of downtown Anchorage, Alaska, makes some fine brews - which I will have to call geo-beers because of the name of the brewery.

The Sleeping Lady Brewering Company is inside and part of the Snow Goose Restaurant. In fact, as you can see from their website, the two are inseparable.

building When we arrived, it was snowing pretty hard - but first we had to use a recalcitrant parking-lot pay machine, which had an exceptionally slow wi-fi access for running credit cards; so, we used cash and gave cash to everyone in front of us so we wouldn't have to stand in line forever. The machine was very picky about how fresh and crisp your bills were. And it didn't like the new large-face-Abe $5 bills at all.
frontNow, having duly paid our parking fee, we can cross the street and approach the front entrance.
snow goose The Snow Goose Restaurant sign and logo, with a stylized Sleeping Lady under the goose. It's really not very many restaurants that have a roche moutonnée as part of their logo.
brew pub We are now about to enter the main front entrance, which is labeled PUB and is draped with the commonly seen white lights of Anchorage, sometimes known as The City of Lights. Still snowing.
ipa Finally, we are inside, where Mom, Dad, and I order an IPA - at least one each. There are several beers to choose from, including all their unique beers, their specialty brews, and their year-round taps - all of them good as far as I know, good depending somewhat on your own personal tastes in beer. I'm referring, of course, to the brews made by the brewery, not to other beers or ales. Also, check out this current beer menu with color chart [former link no longer available].

I think we had the Fish-On IPA, seen above in the Sleeping Lady Brewing Company glass. The Sleeping Lady is shown as a black or dark brown mountain covered with white snow under a blue sky.

Another tempting-sounding brew is the Forty-Niner Amber Ale, which would be a true geo-beer, except - as Andrew pointed out below - "Forty Niner" refers to Alaska being the 49th state (1959) rather than to the California gold rush of 1849.

porter MOH ordered this dark brown Portage Porter, named after the Portage Glacier. Portage Porter is a true geo-beer and glacier beer. Brown is not usually my flavor in beer, ales, or porters - so I didn't order one. Again, the white shape beneath the goose is Mt. Susitna, The Sleeping Lady, a roche moutonnée. (I keep emphasizing that so I can practise my spelling!)
outside Looking out the windows of the Snow Goose Restaurant, one can sometimes see The Sleeping Lady herself - but not this time. This time it's just snow and reflections. A nice night to stay inside.
quilt The restaurant walls have various Alaskan-themed art, including this quilted wall hanging showing The Sleeping Lady (the mountain) in all four seasons. In Alaska, the four seasons are winter, breakup, summer, and freeze-up. Winter is the longest season, of course.

Stick around for awhile, it's still a little nasty outside, and maybe there are some more geo-beers to taste!

Tuesday, March 17, 2009

Happy St. Patrick's Day!

Surprise: a rock with a green mineral in it!

This is a very heavy rock containing three copper minerals: the green one, malachite, a black one, and a reddish-pinkish-purplish one. Large blue squares in the background are centimeters.
A close-up view of said minerals. The little orange bits - which I have to throw in for Alaska Al, who says he isn't from the green part of Ireland - are probably a goethitic Fe-oxide.
Here's the backside of a rock, where some of the malachite crystals can be seen a bit more readily. The bright reddish orange may be a mix of goethite and some other oxide mineral, except for the lower orangey blob, which is part of my finger. The faintly bluish mineral in the bottom center might be chrysocolla.

[How can you tell which side is the frontside or backside of a rock? Simple, the frontside is either the first side you look at, or it's the side facing up when the rock is on the ground or on your display counter. The backside is the other side.]

What are the sooty black and the shiny reddish-pinkish-purplish minerals?

Monday, March 16, 2009

Know-it All Geo-Meme

I'm going to do what Michael Welland did in the comments over at Callan's NOVA Geoblog and list just a few things That Every Geology Major Should Know, rather than try for 10 that no one else has listed. Here are my top four, which are all required to get work in basic mineral exploration:

1. Know how to identify some rocks accurately (notice I didn't say all rocks).
2. Know how to identify some minerals, including some obscure ones, accurately (notice I didn't say all minerals).
3. If you can't identify a rock or mineral, then know how to describe the rock or mineral in question, preferably in well-written sentences when sentences are necessary.

[These are the three main things, four counting writing about rocks and minerals, that I taught to upper-class geology majors when I was in grad school. The writing part was the hardest to teach - many students thought it unimportant.]

4. And I'd really prefer for all geology majors to understand that all the things we use are either grown from or on the earth (plants and animals) - or they come directly from the earth itself, from minerals, elements, and related earth products or chemicals.

Presumably all geology major or graduates know these things.

Sunday, March 15, 2009

WoGE Announcement!

Come one, come all! Where on (Google) Earth #164(?) was just posted at Ron Schott's Geology Home Companion Blog. He's calling it the "Davy Jones edition" and says that whereas no Schott Rule is in effect, he asks that "recent winners give the newbies maybe a day or so."

New Geobloggers and previous non-winners are invited to play - as is any blogger who loves maps and Google Earth!

Where in the West: Mt. Susitna

A Life Long Scholar, who blogs at Musings of a Life-Long Scholar, first identified the March Where in the West as The Sleeping Lady of Anchorage, Alaska - a mountain more formally known as Mt. Susitna. A Life Long Scholar described the mountain:
That is the Sleeping Lady who rests across the inlet of what is now Anchorage, Alaska. Her hair streams off to the left of the photo, her toes to the right. She has slept there for a very long time, awaiting the return of her lover. The shape of the mountain was carved by the advance of the glaciers which once covered her resting form.
The mountain's shape resulted from passage of ice across the land; the name came from a Dena'ina legend.
Geology Happens identified the geomorphology of the mountain: Mt. Susitna is a roche moutonnée. Roches moutonnées are elongated rock masses, sometimes as large as mountains, carved by glaciers. The long axis of a roche moutonée is elongated in the direction of ice travel, with a gently sloped and smooth side facing in the upstream or up-ice direction (stoss side) and a steeply sloped and rough side facing in the down-ice direction (lee side). This overall shape is opposite to the shape of a drumlin, another glacial geomorphic feature, one made of glacial till or drift rather than of bedrock.
The gently sloping, smooth side is on the right or north, the steeply sloping, rough side is on the left or south. The ice moved from north to south.

The first photo is from spring or late winter, 1998, looking down Turnagain Arm and across Cook Inlet; the second is from early March, 2007, looking across Anchorage and Knick Arm from Flattop Mountain; the third is from early March, 2009, looking across Knick Arm from the top of the 5th Avenue Mall parking garage. As you can see, I usually manage to get photos of Susitna when it is at least partially snow-covered.

MSRMaps location; coordinates and other maps.

Saturday, March 14, 2009

The It's Barely Spring Meme

Kim at the ALL NEW All of My Faults are Stress Related (on Scienceblogs), Callan at NOVA Geoblog, and Gelology Happens have all been out finding signs of spring in their areas -- so, while up the hill on our most recent hike, yesterday, MOH and I duly looked around to find some signs of spring. We found some!

First off, there was barely any snow below 7000 feet except on the steepest of north-facing slopes (where there is still enough to inhibit field work); second, there was a lot less mud than I expected. (We are lucky enough to have a south-facing hiking hill, and our snow and mud sample might be considerably biased!) Third, as far as plants and other green things, we found hints of grass and other tiny growing things here and there, including these green leaves poking above last year's mounds of dried leaves.
These little plants will bloom with yellow flowers when they get tall enough. (That's a half a wool-gloved finger in dark blue for scale.) My haiku about them:
Tiny paintbrush leaves
poke up through snow-melt mudflows:
Spring, mostly hidden.
Never mind that they won't grow up to be Indian paintbrush; it's the thought that counts.

Mudflows, what mudflows? Little mudflows - and larger ones here and there, especially higher on the hill - some coming directly from presently melting patches of snow; others possibly coming from water oozing underground and then out to the surface (or the snow has all melted directly above the seemingly source-less mudflows). Here's a small mudflow near the bottom of our hill.
Many, like this enlarged part of a slightly larger mudflow about half-way up the hill, had active bubbles in gooey, muddy water: the bubbles can be seen above in the lower part of the mudflow to the right of the boot. These bubbles dry and leave relict bubble shapes, which can be seen in the upper part of the mudflow mostly above the boot. This mudflow, like many, had no apparent or immediate snowmelt source on the slope above it.
The still wet mudflows will eventually dry and harden into an almost concrete - like these two side-by-side flows above - which we saw about one year ago today. A dime was carefully placed on the right mudflow for scale.

Friday, March 13, 2009

Friday Fault Photos #12

Just a quick post showing some photos I took from the air while flying back from Alaska. These particular photos were snapped over south-central Oregon, about 25 km south of Christmas Valley and about 20 km northeast of the north end of Summer Lake, pretty much out in the middle of nowhere.
The photo above zooms in on a linear structure, which is highlighted in part by snow and which appears to be a small-offset fault cutting through some layered, probably basaltic volcanic rocks. We are looking about due east. The steep-sided, northeast-facing wall running parallel to the fault (facing away from us and not seen in the above photo) is part of the Diablo Rim, about 5 km northwest of Diablo Peak, near Diablo Flat and Murphy's Lake (MSRMaps location).
Stepping back a little and looking at the area from a slightly more northerly angle - that is, looking about ESE - that same fault is in the lower right of the above picture. This photo also shows the really nice alluvial fan that comes out of the mouth of Sand Canyon.
Here, we've stepped even farther back, looking at a larger area from the same angle as in the last picture. Numerous linear features can be seen in the foreground and background. These features include the uplifted and tilted edges of basalt flows, which are cut by faults running north-south, northeast-southwest, and northwest-southeast.
The linear nature and locally rhomboid shapes of the faults and flow edges are accentuated somewhat by this low-angle Google Earth image.

Thursday, March 12, 2009

Going to Gabbs?

I'm not planning to go to Gabbs any time soon, but here's a map of the state of Nevada as seen last year on a market wall in Gabbs - north Gabbs, to be precise. Gabbs is that yellow star in west-central Nevada.

We are back from the cold, snowy up-north country of Alaska. It's clear and sunny here at our little house in eastern Nevada, with ice and snow melting and temps gradually warming, at least for now. (It really isn't spring until all mud goes away, IMO.)

Later today I'll check for signs of spring as per recent meme - but I don't expect to find any other than melting, melting... To find spring here, go south - like to Gabbs, NV or Mojave, CA or Death Valley maybe.

I'll catch up on things shortly, while preparing for job finding, meeting attending, and whatever else besides bunched up email, unpacking... oh, the list continues!

Monday, March 9, 2009

Roads of Stone

Roads of Stone is a great blog by a geologist who happens to be a runner - or maybe it's the other way around. I've been meaning to say something about this blog for a while; it's been listed in my sidebar since forever (forever started early last year).

Recently, late last year, Roads had a great post combining the geology of the Hog's Back - in what I would call southeast England, south of London - with an annual 8-mile race called the Hog’s Back Road Race. He wrote, in part:
For a hundred million years as the Atlantic widened, a block of old rocks beneath London stood eroding, above a muddy river plain to the south. Then as the coastlines encroached northwards a hundred million years ago, tidal bars and beaches swept sands along their reach.
And later on:
It’s a fantastic story — the geological history of the past two hundred million years defining the lie of the landscape I’ll run across today.
locationJust to get you interested, I'm showing here a location map with some general geology and a photo not shown in his post.stair hole inversion monocline lulworth cove dorset england looking west by roadsofstone.jpg

Photo by roadsofstone.com of the stair hole inversion monocline, Lulworth Cove, Dorset, England.

Go check out this post on a great example of "the biggest inversion monocline in all of Southern England." And while you're there, read more about other parts of the world, where roads, running, and geology all come together.

And besides, I'm really into races today, ones of a slightly different kind.