Wednesday, April 30, 2008

Some Recent Energy News

Alaska again rejects Exxon's plan to drill Point Thompson on the North Slope.

Gasoline usage is going down!

Bush tells Congress to open ANWR to oil exploration.

Juneau is using a lot less electricity (and a lot more energy-efficient lightbulbs - and clothespins!) in the aftermath of recent avalanches, which knocked out power lines.

Also, see Clastic Detritus for some news and discussion about suspending the federal gasoline (fuel?) tax.

Is Water Lubricating a Mogul, NV Fault?


This is what I'm wondering. Yesterday, a geologist living in Mogul suggested to me that the recent earthquakes there remind him of the 1970's earthquakes in Denver, which turned out to have been caused by water injection in the area - with the water lubricating the faults and causing the earthquakes. Read up on the Denver earthquakes here with additional references here and here [the latter two are abstracts only]. The amounts of injected water they are talking about for Denver sounds rather large, and the injection (and earthquakes) took place over a considerable period of time.

As Andrew has noted, the Mogul-Somersett earthquake swarm is unusual: it didn't start with a large earthquake and dwindle into aftershocks, and it hasn't reached any kind of climactic peak. Also, the earthquakes have all been shallow. At least one geologist living in Mogul has expressed concern that, with the large Somersett development or subdivision located relatively high on a ridge above the valley Mogul lies in (Mogul is adjacent to and somewhat elevated from the nearby Truckee River and its floodplain), water from landscape watering and from the golf course might be lubricating a possible northwest-trending fault - the Nevada Seismological Laboratory (NSL) has more information about the quakes and a couple maps.

It may be that there isn't enough water seeping into the ground from the hillsides above Mogul to cause these earthquakes, and Ken Smith and Glenn Biasi at the NSL have been busy trying to diminish local rumors about the quakes, including the definitely false one that the local mountain, Peavine, is a volcano (it's not, never has been). From the Reno Gazette-Journal [I suspect some quotation marks are missing, or the paragraphs are parsed strangely].

What about golf courses?

Another question is whether golf courses in th area changed the way the water table impacts the geologic structure.

Earthquakes can follow when the water table is changed, Biasi said. A well-known example is Hoover Dam.

As the rocks have less pressure, they will slip, causing earthquakes.

"Did the golf course perhaps raise the water table and contribute to this?" Biasi said. "We don't think so because you have a river at the bottom [of the valley]."

"It set the water table very high already, so the golf course could not have raised it very far."

Landscape watering would contribute to the problem, he noted. They can't rule it out because they don't know how high the water table was before the [Somersett] development occurred, Biasi said.

"It's a real long shot, but one we don't have any date to comment on," Biasi said.

In other words, it sounds like a possibility, one that has not at all been confirmed. In the meantime, my former colleague (and a couple other geologists?) are trying to contact Mike Alger, the geologist and meteorologist for KTVN Channel 2 and the Reno Gazette-Journal in order to have this issue looked into.

Tuesday, April 29, 2008

Book Meme

This book meme is from John Lynch (Stranger Fruit), and from others farther back than that. It's called the "the top 106 books most often marked as 'unread' by LibraryThing's users." The books I've read are in italics; books I never finished are struck through. I found this meme via Rational Rant.

Jonathan Strange & Mr Norrell
Anna Karenina
Crime and Punishment
Catch-22

One Hundred Years of Solitude
Wuthering Heights
The Silmarillion
Life of Pi : a novel
The Name of the Rose
Don Quixote

Moby Dick
Ulysses
Madame Bovary
The Odyssey
Pride and Prejudice
Jane Eyre
The Tale of Two Cities
The Brothers Karamazov
Guns, Germs, and Steel: the fates of human societies
- will read soon
War and Peace
Vanity Fair

The Time Traveler's Wife
The Iliad - ?
Emma
The Blind Assassin
The Kite Runner
Mrs. Dalloway
Great Expectations
American Gods
A Heartbreaking Work of Staggering Genius
Atlas Shrugged
Reading Lolita in Tehran : a memoir in books
Memoirs of a Geisha
Middlesex
Quicksilver
Wicked : the life and times of the wicked witch of the West
The Canterbury tales - ?
The Historian : a novel
A Portrait of the Artist as a Young Man
Love in the Time of Cholera
Brave New World
The Fountainhead
Foucault's Pendulum
Middlemarch
Frankenstein
The Count of Monte Cristo
Dracula
A Clockwork Orange
Anansi Boys
The Once and Future King
The Grapes of Wrath
The Poisonwood Bible : a novel
1984
Angels & Demons
The Inferno
The Satanic Verses
Sense and Sensibility
The Picture of Dorian Gray
Mansfield Park
One Flew Over the Cuckoo's Nest
To the Lighthouse
Tess of the D'Urbervilles
Oliver Twist
Gulliver's Travels
Les Misérables
The Corrections
The Amazing Adventures of Kavalier and Clay
The Curious Incident of the Dog in the Night-Time
Dune
The Prince
The Sound and the Fury
Angela's Ashes : a memoir
The God of Small Things
A People's History of the United States : 1492-present
Cryptonomicon
Neverwhere
A Confederacy of Dunces
A Short History of Nearly Everything
Dubliners
The Unbearable Lightness of Being
Beloved
Slaughterhouse-five
The Scarlet Letter
Eats, Shoots & Leaves
The Mists of Avalon
Oryx and Crake : a novel
Collapse : how societies choose to fail or succeed
Cloud Atlas
The Confusion
Lolita
Persuasion
Northanger Abbey
The Catcher in the Rye
On the Road
The Hunchback of Notre Dame
Freakonomics : a rogue economist explores the hidden side of everything
Zen and the Art of Motorcycle Maintenance : an inquiry into values
The Aeneid
Watership Down
Gravity's Rainbow
The Hobbit
In Cold Blood : a true account of a multiple murder and its consequences
White Teeth
Treasure Island
David Copperfield
The Three Musketeers



For what it's worth (FWIW), that's 38 read and 5 not completed, although I haven't quite given up on Moby Dick and The Silmarillion. Also, I may be mis-remembering a couple - read or not read!

5 and 10: where has the time gone?

10 years ago in 1998, I was just about to leave Alaska in order to follow my desire (goal?) to get back into the mining exploration industry after a hiatus of many years. The hiatus was due to an unfortunate event that I won't go into right here, right now; it's something I've had to let go of (detach from?). I decided in the late fall of 1997 to get back into the industry, and set about doing so by going to meetings and renewing old contacts. The price of gold had just plummeted to $250/oz or so, and the industry was going into the frenzy (tailspin?) that followed on the heels of the Bre-X scandal/scam, which made it even more difficult for companies to raise money to conduct exploration. So my timing was - well, not the best? Anyway, I had not been able to find a job in Alaska, possibly from starting to look a little too late in the year (who was to know they would be hired-up for a June field season by February?), and probably from not really having any contacts there. I did have three or four job offers from outfits in Reno, at least two of which sounded firm, so I decided to move back to the area I had been centered in for more than two decades. Short story: by the time I had driven down the Alcan and gotten an apartment in Reno, all the job offers had turned to dust.

So, I started beating the bush, pounding the pavement, knocking on doors, making calls. I had several more interviews; money was tight. At some point, a job was passed around through channels: sitting a drill rig - in Nicaragua, in the rainy season, for a pretty low daily rate. I thought about it, could kind of visualize it, didn't like what I saw, and didn't apply for the job.

Being kind of impatient at times, I didn't feel like I could just sit around waiting, calling and waiting - even though I figured I could find something agreeable by fall. I couldn't wait that long. I needed something to occupy my mind and self, so I started volunteering at a local kindergarten. It was one of the best things I had done for myself (and others) for a long time, besides moving to Alaska for two years. By fall, I was considering getting an education degree so I could teach Earth Science in high school; by the end of the year, I had enrolled in a program to do so. I would never have imagined myself doing something like this even 5 years prior, and certainly couldn't have imagined it when I was an undergrad or grad geology student - and wouldn't have even considered it as a possibility.

For various reasons, I found I probably wouldn't like teaching in high school (I really have never liked high school students very much, even when I was there - and that is something I've been having to let go of, also, now that two nieces and one nephew are in high school, and one niece just graduated a couple years ago), so I re-oriented myself toward teaching in elementary school. I didn't make it - did not make it through student teaching after trying with two sets of teachers. I was still fairly sure I could do it, on a third try I was planning for the following fall - when opportunities changed. MOH and I moved to "the lake" to follow jobs in home construction and to move to an area we had become interested in (I had been working at that with him that one summer; by then it was the summer of 2001). I had set two goals - consulting and teaching - and those hadn't panned out! I had met MOH in the process of all that, and that has worked out!

5 years ago in 2003, with the above story having shifted gears but still continuing - I was just about to lose a job in construction, as a carpenter's helper, a job I'd had for a short time (in the meantime, I'd done a lot of artwork, had sold some things, was too impatient to stay at it, at least to make a money-making career (ha!) out of it). And I was just about to quit a second job in construction after less than a week, working for a very strange person who ultimately gave me the creeps. I had also, not long before that, taken some classes in soil science, and was just about to get a short-term job sitting around outside watching leach tests for septic tanks, working for - ?? - $50 per test - which amounted to less than $10/hour. That didn't ultimately appeal to me very much, and it was barely geological (although I could do art part of the day) - so, late in 2003, coming back with MOH from a trip to "our" hot springs in central Nevada, I looked up at some ash-flow tuffs lying there just off the side of the road, and suddenly - it came to me: I can do that! I can still do that - I can still map and do geology! What a revelation.

I set about, once again, getting back into the business of exploration geology. The price of gold was up, and companies were coming out of the woodwork. It took 3 to 4 months, but I got a job (sitting a drill rig) - my first job ever as a consulting geologist. (Maybe I was less impatient this time?)

I had thought, when I got out of the business for personal reasons, that if I didn't get back into the business in 5 years, that I would never do it, that it wouldn't even be possible, that I'd be out-of-date and no one would want me. My first attempt, in 1997-1998, had already been 2 years past my "due date" - doing it in 2003-2004 was more than ten years down the line. It worked, nevertheless, meaning that my idea of what was possible, and my long-term planning ideas, really were out of touch with ultimate reality. But then, my mom and dad (M+D), had always told me when I was growing up - you can do/be anything you want. (Obviously, though, I'm not really cut out to be a major league basketball player.)

Goals? I'm not really great with goals or long-term planning, and have found that some of my best ideas have been almost spur of the moment things, ideas that have ultimately taken me to places I never would have imagined - like being a field geologist. I never thought I was cut out for that, but circumstances and choices I made showed me that I was wrong about that.

I've had three major goals in my life: 1) move back west after moving east, 2) don't become a secretary, and 3) go to grad school. The first goal I developed at the age of 10 prior to moving east from the west coast to follow M+D when my dad got a job back east. I knew I would come back here (The West); I knew I would do it as soon as possible (at the time, I was thinking 5 years max, but by then I was in high school, and it wasn't quite the right time for me to move on my own!). The second goal I accomplished by not taking typing in high school (I took it later for my own use when it was clear I wouldn't somehow get sucked into the secretarial direction). The third goal, grad school, came to me in a matter of minutes during a personal crisis, in which a sig-oth was telling me that - I would quit undergrad school, I would move into this really awful old, falling down farm house, and I would become a - what? - housewife? Or he would leave me! Yikes! (BTW, don't ever, please, give me an ultimatum!) While crying, I told him that those things absolutely weren't possible, and at that second, I knew I was going to grad school to get my M.S. in geology.

Quite frankly, I never imagined myself as a field geologist, not until I became one, and I never really planned on being a consulting geologist, either. (I didn't really plan on getting any gray hair, but - oh, well). And I think that's "deep enough," as they say in the mining industry.

A Brief Update: BTW, I have the deepest respect for women who have chosen to be what was known then as a housewife - my mom, for one, and my exceptional bright and talented sisters, for two and three. It just wasn't the right thing for me at the time.

scientiae carnival

Monday, April 28, 2008

Detachment News: A New Book Series

I might have to look into this book, written by geologist Susan Cummins Miller, and the rest of her fiction series involving a geologist protagonist and some geological and desert settings.








Frankie MacFarlane Mysteries

A Recent Hike

Up the hill on a recent hike, besides seeing some great views, I ran across a few wildflowers, and lo and behold, the penstemons I mentioned a week ago or so turned out to be Astragalus species, more commonly known as locoweed. This one might be A. utahensis, A. purshii, or A. humilumus, or possibly some other one - there are millions (hundreds?). In any case, these purple flowers are pretty, and are growing rapidly.

Among other wildflowers, I also spotted these yellow flowers, which I think are Physaria species, sometimes known as twinpod or bladderpod, and this one might be P. fendleri, but maybe another, similar bladderpod.

I've been having a hard time finding links to Nevada wildflowers, and so have been relying on this book, which has the basics, and online links to wildflowers of the southwest and of Colorado, for example this site.

The Triloblog - And a Trilo-Song

Some information for everyone - and for some certain Alaskan readers - by way of The Lost Geologist: I have added a link to Triloblog in my links sidebar, for all of you fellow Trilobite lovers.

Trilobite, trilobite,
Trilobite, trilobite:
Trilo trilo trilobite,
Trilo trilo bite bite bite,
Trilo trilo trilobite,
Trilo bite bite bite,
Trilo, trilo, trilo, trilo trilo trilo, bite bite bite
Trilo trilo trilo trilo trilo trilo, bite bite bite.
Trilo trilo trilo tri trilo tri bite bite bite,
Trilo trilo trilo tri trilo tri bite bite bite.
Trilo trilo trilobite,
Trilo trilo bite bite bite,
Trilo trilo trilobite,
Trilo bite bite bite!

BTW, the song (except for the two beginning lines, is sung to the tune of the "William Tell Overture" - the Lone Ranger tune) - is called - (you guessed it) The Trilobite Song!

Saturday, April 26, 2008

Yerington: Day 1, Pt 3: Sodic-Calcic Et Al

It's hard to believe I'm still on the first day - but I think it's just a matter of being a photophile and not having as much time as I'd like.

Hand points to the part of the Ann-Mason fault block that we started in.

From the Bluestone Mine, we took the vans north to a hill where we were able to examine some intrusive contacts within the Yerington batholith and also some sodic-calcic alteration. The alteration types we spent much of the day looking at were obscure to almost cryptic (or at least it seemed that way to me!).

At Stop 3 of Day 1 [Stop 2 in the guidebook referenced below], we saw the deepest exposure of the Yerington batholith. (The batholith consists of three major intrusive bodies: the oldest, the McLeod Hill quartz monzodiorite; the second, the Bear quartz monzonite, and the youngest, the Luhr Hill granite and related granite porphyry dikes.) The most noticeable and impressive thing about the quartz monzodiorite at this exposure were the large epidote "splotches" - replacements following tiny fractures. The epidote splotches have bleached selvages where the original K-feldspar, biotite, and magnetite are gone, replaced by or altered to plagioclase (albite), amphibole, epidote, and sphene.

Epidote splotches in quartz monzodiorite.


Some relative age relationships between different kinds of alteration features.


The age relationships between the different alteration features, including early endoskarn and later sodic-calcic alteration were a little hard to keep track of, and some of the key veinlets were narrow to cryptic. In the above photo, an early greenish amphibole-diopside veinlet (endoskarn) is cut by a dike. The dike also cuts epidote splotches and associated bleaching (sodic-calcic alteration), so the dike is probably related to the late granite intrusions.

Sodic-calcic bleaching of quartz monzodiorite.


The sodic-calcic alteration, above, has gone outward from narrow fractures and veinlets. This type of alteration is thought to be related to non-magmatic brine fluids, which were drawn into the edges of the magmatic-hydrothermal system. Sodic-calcic alteration is often related to IOCG deposits, examples of which are some magnetite skarns found around the edges of the large Yerington porphyry copper system.

Granite porphyry on the right, with chilled margin, intruding quartz monzodiorite.


Luhr Hill granite on the left, with chilled and foliated margin, intrudes quartz monzodiorite.


Ann-Mason deposit in the wind.

Onward we went, through the day here and there, as it got windier and windier, finally coming to the not-in-production (too deep) Ann-Mason porphyry copper deposit, to the west of the Luhr Hill cupola and main mass of granite porphyry dikes, upward in the system with west being "Jurassic Up." And we found: more sodic-calcic alteration and some tourmaline breccia.



Finally, we reached the culmination of the day, an antelope seen while heading back to Yerington.



Main Reference:

Dilles, J. H., Proffett, J., and Einaudi, M. T., 2000, Field trip day two: Magmatic and hydrothermal features of the Yerington Batholith with emphasis on the porphyry Cu-(Mo) deposit in the Ann-Mason area, in Thompson, T. B., ed., Society of Economic Geologists Guidebook, 32, p. 67-89.

Chuck has posted another IOCG link. Check it out!

Thursday, April 24, 2008

The Serpentosphere: An Update

One author of the abstract I quoted in an earlier post - the talk about The Serpentosphere given at last month's GSN meeting in Reno, NV - contacted me via comment on this blog. Martin Hovland pointed out his website, which has numerous references to the interconnections between mud volcanoes, salt diapirism, hydrothermal activity, and deep sources of hydrocarbons and some interesting links. He also referenced his EOS 2005 paper on the Chapopote asphalt volcano. At least one petroleum company is using ideas discussed at the March GSN to find oil.

Andrew on Nonmagmatic volcanism:


There are less well-known types of volcanism that don't involve magma: mud volcanism is one. Mud volcanoes come in two types. On land, hundreds of them occur in areas where hydrocarbons are abundant, like Trinidad or Azerbaijan (see this one in the Image Gallery). Under the sea, thousands of them occur near subduction trenches, where serpentinite mud is abundant (about serpentinization).


Another newly discovered form of volcanism involves asphalt. Asphalt flows were first documented on the floor of the Gulf of Mexico in 2003. No one knows how many of these tar volcanoes there are.


A few more references:
Supercritical water and Hydrothermal Chimneys
Lost City hydrothermal field
Asphalt Volcanism
Mantle Serpentinization Rates
Carbon Degassing from the Lithosphere [and upper mantle]
Mud Volcano Tofu
Mantle Wedge Water Contents

MagmaChem
Tornado Gold

Tuesday, April 22, 2008

Here Comes the Sun



Today is Earth Day, and so I'm giving you some pictures of the rising sun and an early-morning sun dog -- the atmosphere and atmospheric phenomena are part of the earth and part of our everyday experience.

I remember the excitement and hoopla that attended the first Earth Day back in 1970, when I was still in high school. People were optimistic about what they could do, and yet much pessimism was focused on the way things were. I'd like to remind everyone that a lot of good has been accomplished since those days: rivers on the east coast are much cleaner, and you can see the mountains that surround L.A., which was rare in the early 1970's. The air we breathe today is cleaner in many places than it was on the first Earth Day in 1970. Look up. Enjoy the view.

I occasionally participate in Earth Day clean-up programs, but what I really have enjoyed over the years is participating in Earth Science Week field trips - field trips which are designed to introduce geology to the general public, including children of all ages. These field trips are run every year by the Nevada Bureau of Mines and Geology I think in conjunction with the Geological Society of Nevada). Here is an example of an Earth Science Week field trip program.

I like what Julian has suggested about remembering and honoring the brown places, because I have been a desert person for several decades. And I like Andrew's suggestion to read science fiction in order to become familiar with envisioning alternative futures.

Andrew also summaries several other good Accretionary Wedge #8 posts.

Accretionary Wedge #8: Earth Day the Geologists' Way

Monday, April 21, 2008

My Hiking Hill

Here's the hill I hike up for exercise and enjoyment. It's a long way to the top! The bunch grass is turning green and a few small penstemons locoweed flowers have popped up.
Above, an arrangement of sagebrush, a lichen-covered rock, and some old rusty junk.A view looking back down the hill at our little house, the yellow one.

Sunday, April 20, 2008

Geologist for... ?

Thanks to Dinochick for the Glassbooth quiz.

The first time, I came out 80% similar to Ron Paul, a Republican running as a libertarian, 72% similar to Mike Gravel, a Democrat running as a libertarian, and 64% similar to Barack Obama. I had limited my choices of issues to just a few, so then I took the quiz again.

The second time, I came out 76% similar to Mike Gravel, 71% similar to Barack Obama, and 70% similar to Ron Paul. That change came largely as a result of adding my anti-gun-control stance.

The third time, I added only gun control issues to the four I had chosen the first time, and in the results, they left that issue out entirely. Consequently, I have to conclude that the quiz is biased, because it came out identical to the first time.

Also, the way they define some of the issues is different from a simple "strongly oppose" or "strongly agree" response on the quiz - for example, when I said I was for "free trade," somehow that equated to being for NAFTA, which isn't really free trade, it's strongly regulated trade, legislated trade.

But, hey, that's as far as I'm getting into this sort of s***! Interesting quiz, though - after reading it, I'll probably have to vote either libertarian or Republican. Well, that's months away, plenty of time to decide...

Saturday, April 19, 2008

A Quick Note Before Work

A quick note for a Saturday morning while I'm having morning coffee: The weather has been pretty good here recently - relatively warm and mostly clear - at least until yesterday afternoon when the wind picked up. Temperatures might be a bit cooler today, with an expected high of 48 degrees F, and a wind advisory has been posted! When it gets windy and dusty at the mine (much of the summer months) the water truck (trucks?) sprays water everywhere - and hopefully not too much so the roads don't become slippery for the huge haul trucks driving around, carrying ore to the crusher and ore piles and waste to the various waste dumps.

We have had dry roads and no mud for at least a couple weeks, but because they sprayed water yesterday, MOH and I now have bits of dried mud -dirt! - scattered through the house from MOH's boots. I didn't get muddy boots because the roads I use weren't sprayed, although that could change if the winds become persistent.

I'm currently working my mostly 10-hour days, leaving for work around 6:30 am, getting back from work by 5:30 pm. MOH is on days right now, which means that we see each other in the mornings and at night. He leaves here at about 5:00 am and returns usually by 6:30 pm. We both are to bed around 8:00, lights out at 9:00, and so my time for blogging and fixing up photos, etc, is seeming a little limited. Oh, well!

Hope everyone is having a good weekend. For me, I think it's still Tuesday!

Thursday, April 17, 2008

Yerington Day 1, Pt 2: The Singatse Fault

Well, here we are at the Bluestone Mine, looking off the to northwest, toward Yerington - more or less. The view is mostly of Mason Valley, with Yerington possibly visible to the left in the middle distance, and the Desert Mountains forming the horizon in the far distance.

At the Bluestone Mine, we first examine one of the 2nd-generation low-angle normal faults, seen in the prospect face above the orange-vested, bending-over, back-to-us geologist. This 2nd-generation fault overall dips about 30 degrees, although here the apparent dip is closer to 45 degrees. In this photo, it's a sharp fault, and you can almost see dip-slip slickensides just a little above and to the left of aforementioned geologist. This second-generation fault cuts first-generation normal faults, like the Singatse Fault. See earlier post. (Also for more references.)


After scrambling around on a hillside or two looking at some sodic-calcic alteration minerals and some intrusive contacts (future post), we finally get to a viewpoint where, looking south, we can see the Bluestone Mine and the main 2nd-generation fault, which is marked by the color change between the brownish, mineralized, hanging-wall rocks and the whitish, intrusive, footwall rocks - and approximately marked by a yellow line someone inserted into the photo.

Singatse Fault:

After even more scrambling around hillsides, up and down, over and beyond, we came to our lunch stop and the Singatse Fault, one of the major 1st-generation low-angle normal faults, which can be seen above in a trench made just to expose the fault. Here, the Singatse Fault juxtaposes sheared quartz-sericite-pyrite-altered intrusive rocks of the Yerington batholith in the hanging wall against shattered Luhr Hill Granite in the footwall (both are Jurassic in age). I dug around in this exposure, but couldn't find any good sense-of-motion indicators - the pieces just crumble and fall apart.


The Singatse Fault runs up the canyon to the west, where it can be seen in old drill roads to the north, marked by a color contrast between the reddish Tertiary volcanic and sedimentary rocks above (hanging wall) and the whitish Jurassic intrusive rocks below (footwall).


Here, someone had conveniently dug out another example of the Singatse Fault, and had equally conveniently placed a flagged rock hammer on the contact. By the time we reached this spot, which is on a pass exposed to the elements, the wind was blowing hard enough to knock small people over, and everyone had huddled into the small pit where the fault was exposed for cover.

Coming soon: sodic-calcic alteration and some intrusive contacts. Also, we'll see the Tertiary unconformity and possibly one more example of the Singatste Fault.



A "Lost" Gold Mine

I'm back to work today and so will just post this short anecdote.

The above major dirt road, which heads east from just north of Schurz, NV (Schurz is a tiny place on Highway 95 between Fallon and Hawthorne) will take you out to what may be an undiscovered gold deposit, that is, if you know the right side roads to take.

I "discovered" this place in the mid/late 1980's, an area of nicely altered Tertiary volcanic rocks, altered in a way that reminded me a lot of the major, high-sulfidation (back then called "quartz-alunite") gold mining camp of Goldfield, NV. There had been a few drill holes in part of the area, and some white claims posts were lying around here and there. The entire area, however, had not been drilled, including some hard to find quartz-alunite-altered rocks hidden at the bottom of some minor dry washes. I took a bunch of samples, made a sketch map of the area, and drove to Fallon - the county seat - and checked the claim records for the area.

There were no active claims, and despite the claim posts scattered here and there, it didn't look like any claims had been filed recently. Sometimes prospectors, geologists, and mining exploration companies will put up discovery posts, and then not file the claims if the assays don't look too good, because in Nevada, one has 90 days (I think, or at least 30) to put up all claim corner posts and file the claims with the county and BLM.

I called in to the office, and claim stakers were shortly on the way to the area, because whether or not any samples I took came back good or not, the area wasn't very far from the Paradise Peak and Rawhide, two major gold mines located nearby, and I thought the alteration itself looked good enough to warrant staking and then mapping and sampling at the very least. After acquiring the property by staking, the mapping and sampling we would do would determine whether or not we would want to drill the property, and if so, where.

Well, while the claim stakers were enroute, our landman determined, after a lot of digging around, that despite info from the county courthouse and state land map, the area had been recently "taken" by the Navy, without going through all appropriate channels - like legislation - which is why there were claim posts but no county filing of the claims. Someone else had found the area, staked it, and then found out the area was technically unavailable for mineral entry (claim staking). We called off our claim stakers (staking is often done by separate, surveying-type outfits), and I went back out to see what else I could find.

So there is a possible gold mine out there, between Schurz and Fallon, where the land has been withdrawn for Naval flying and exercises.

Tuesday, April 15, 2008

Yerington Day 1

Day 1 of the field trip was an overview of the Yerington mining district, a touring day of driving here and there along with a couple moderately long (or steep) hikes. We started at Weed Heights, just above the old Anaconda open-pit, the dumps of which are visible from the town of Yerington. We had a round of introductions - geologists present were largely from outside the United States, most were from Canada but countries included Mongolia, Italy, Sweden, Mexico, a few South American countries, and one American living in Australia and working in southern Africa. Several languages were spoken, the dominant ones being English, Spanish, and French. We had one or two students on the trip (or more?), several relatively young geologists working mostly in Canada, and a number of older geologists. The day was cool and partly cloudy, and every time we stopped, we got out a set of maps, cross-sections, and diagrams and had mini-lectures standing in front of one of the vans, which was used as a magnetic bulletin board.

Weed Heights Post Office:

Weed Heights
Yerington pit, with ducks swimming in the non-acidic, non-copper-colored blue-green water (acidic water with a lot of copper in it is often a deep or bright blue-green):

open pit
Our fearless leaders, Dick Tosdal and John Dilles:


leaders
Anaconda mined the deposit from 1951 through 1978. A brief history and summary on the tires below (enlarge as needed):




legendThe field trip was very interesting, both geologically and with regard to scenery, plant life, and wildlife. Geologically speaking, the field trip could be called, "Detached or Not: the 200% Extension of a Major Porphyry Copper Center in Western Nevada." This is the area mapped first by Proffett and Proffett, by Proffett and Dilles, and by Dilles, Proffett, and Einaudi, and also by others.

map


Normal faults, which are now dipping 20 degrees in most places, but which initiated at 60 degrees or more, have essentially cut the district and the porphyry copper system into large and thick tectonic slices. One can now view the Jurassic porphyry system essentially in cross-section by looking at it on a map after turning the north arrow to point to the right. "Jurassic Up," the direction that was up in Jurassic time, is then at the top of the map - west - with the now tilted Tertiary unconformity that eroded the upper, shallower part of the porphyry system sitting on top of the older rocks in what amounts to a cross-sectional view. The porphyry dikes, which in actuality strike east-west and dip about 30 degrees to the north, will - after rotation of the geologic map as I just described above - appear to be vertical, as if in cross-section.


cross-section In the upper (real) cross-section, you can see the major low-angle normal faults that have cut the Jurassic through Tertiary into thick slices and tilted the entire section. Apparently, if these faults sole downward into any kind of regional detachment fault or fault system, it has not been discovered and is probably too deep to be found, if present. That is, no brittle-ductile contact zone - such as is found in major core complexes like the one in the Snake Range of eastern Nevada (see banner photo), or the Ruby Mountains near Elko, Nevada - is known or has been recognized. The lower (real) cross-section shows a fold affecting Triassic to Jurassic sedimentary (and volcanic) formations, probably folded in Jurassic time prior to intrusion of the Yerington batholith (if my f.t. notes serve me correctly).


map
The area visited during day one is thoroughly covered by the enlarged geologic map shown above, with north up and the larger squares equal to about one mile (a township section). Below, I've rotated the map so that north is to the right and west is up. I've labeled the Singatse Fault in yellow, one of the major low-angle normal faults; the Tertiary unconformity is in turquoise in two places in the upper, western part of the map; a cupola of the Yerington batholith, also in turquoise, is in the lower, eastern part of the map; and the approximate axis of the fold is in dark blue near the left or southern part of the map. Porphyry dikes cut through the center of the map in a mostly westerly direction (WNW). They come out of and intrude the cupola of the batholith and then cut through other plutons of the batholith complex, which are in a kind of beige color.


rotated map

With the rotation of this map so that "Jurassic Up" is located to the top of the map, one is now viewing the area in a cross-sectional fashion, except for the various normal faults that have sliced things up. The anticline is now seen as a mostly upright fold; the dikes shoot "upward" out of the cupola and into the rest of the porphyry system; and the Tertiary unconformity, which has an erosional conglomerate or breccia sitting on top of it, that overlain be Tertiary volcanic rocks, is now seen to overlie the entire mass of pre-Tertiary rocks. It's not a perfect "cross-section" that one looks at in this fashion, but it shows the main elements very well.

The Tertiary faults that tilted the Tertiary and older rocks began about 14 to 15 million years ago. Prior to Tertiary tilting, Jurassic tilting of the porphyry system and older rocks had amounted to about 20 degrees. Tertiary tilting took place on three sets of normal faults, all of which can be seen in the upper (real) cross-section. The earliest set, about 14 to 15 Ma, are the ones now dipping about 20 degrees, like the Singatse fault. The second set of normal faults were active from about 12 to 9 million years ago, cutting and tilting the earlier set of normal faults. The third set of normal faults, amounting to the Basin and Range faults of this area, became active about 7 to 8 Ma. These faults cut all previous faults, and have added somewhat to the tilting of the faults and strata of the area. Tertiary faults have tilted section and all units about 60 to 70 degrees, resulting in a total tilting of about 80 to 90 degrees since the Jurassic.

Just for all you volcanology fans, I've included a cartoon of the Tertiary volcanic section below.

Tertiary section


Some references:

Dilles, J. H., 1983, The petrology and geochemistry of the Yerington batholith and the Ann-Mason porphyry copper deposit, western Nevada, Stanford Ph.D dissertation.

Dilles, J.H., 1987, The petrology of the Yerington batholith, Nevada: Evidence for the evolution of porphyry copper ore fluids: Econ. Geol., v. 82, p. 1750-1789. Econ. Geol. online.

Dilles, J.H., and Einaudi, M.T., 1992, Wall-rock alteration and hydrothermal flow paths about the Ann-Mason porphyry copper deposit, Nevada--A 6- km vertical reconstruction: Econ. Geol., v. 87, p. 1963-2001.

Dilles, J. H., Proffett, J., and Einaudi, M. T., 2000, Field trip day two: Magmatic and hydrothermal features of the Yerington Batholith with emphasis on the porphyry Cu-(Mo) deposit in the Ann-Mason area, in Thompson, T. B., ed., Society of Economic Geologists Guidebook, 32, p. 67-89.

Dilles, J.H., Proffett, J. and Einaudi, M. T., 2005, Magmatic and Hydrothermal Features of The Yerington Batholith with Emphasis on the Porphyry Cu(-Mo) Deposit in the Ann-Mason Area, in Geological Society of Nevada, 2005 Symposium Field Trip, Guidebook 9 Porphyry Deposits of the Great Basin.

Dilles, J.H., Solomon, G.C., Taylor, H.P., Jr., and Einaudi, M.T., 1992, Oxygen and hydrogen isotopes characteristics of hydrothermal alteration at the Ann-Mason porphyry copper deposit, Yerington, Nevada: Econ. Geol., v. 87, p. 44-63.

Dilles, J.H., and Wright, J.E., 1988, The chronology of early Mesozoic arc magmatism in the Yerington district, Nevada, and its regional implications: Geol. Soc. America Bull., v. 100, p. 644-652.

Proffett, J.M., 1977, Cenozoic geology of the Yerington district, Nevada, and implications for the nature and origin of basin and range faulting: Geol. Soc. America Bull., v. 88, p. 247-266.

Proffett, J.M., and Dilles, J.H., 1984, Geologic map of the Yerington district, Nevada: Nevada Bur. Mines Geology, Map 77.

Proffett, J.M., and Dilles, J.H., 1991, Middle Jurassic volcanic rocks of the Artesia Lake and Fulstone Spring sequences, Buckskin Range: Geol. Soc. Nevada, Field trip 16 guidebook compendium, v. 2, p. 1031-1036.

Proffett, John M., and Dilles, John H., in press 2006, Lower Mesozoic sedimentary and volcanic rocks of the Yerington region, Nevada, and their regional context: Geol. Soc Amer Spec Paper, editors, John Shervais and Jim Wright.

Proffett, J.M., Jr., and Proffett, B.H., 1976, Stratigraphy of the Tertiary ash-flow tuffs in the Yerington district, Nevada: Nevada Bureau of Mines and Geology Report 27, 28 p.


Monday, April 14, 2008

Recent Travel Continued

I recently traveled to Yerington, Nevada, in order to participate in a geological short course on mapping porphyry copper deposits and alteration types related to the deposits. The mining district in question is the huge area of the Yerington porphyry copper deposits, related skarn deposits, and related possible IOCG deposits (Iron-Oxide Copper Gold). This short course was put on by a group called MDRU, and was led by geologists John Dilles and Richard Tosdal. The course was excellent.

I traveled to the course by way of some back roads or side trips. I drove these side roads so I could take some photos for future use. I turned south from Highway 50 at Middlegate Junction (the location of Middlegate Station, a great place to get burgers and fries), then took Nevada Route 361 down to Gabbs.


361
Gabbs is the site of a long-standing magnesite mine, now operated by Premier Chemicals, LLC, and formerly, for a long time, operated by an outfit called Basic.


magnesite
I drove through Gabbs - north Gabbs and south Gabbs - and took a few photos: of the grocery store, the gas station, the old cafe, which appears to be closed, and a few the houses and signs.


Gabbs
I then drove southward to the Poleline Road, a main dirt road from Gabbs to Tonopah, stopping first at what used to be an old bar and pool hall next to the old Keystone Mini Mart. It was long ago a favorite hangout of many geologists, especially those at Former Mining Company.

Pole Line
Then onward I went, turning south onto Pole Line Road. I drove down it a ways, taking various pictures, before I turned around and continued on my journey to Yerington.


Pole Line south
Pole Line north


The Pole Line Road to Tonopah is the site of one of my early geology stories, one about looking for my thesis area, so I needed some photos. These photos, or ones like them, may appear later in stories that I call exploration stories, Highway 8A stories, or Mojave Exploration stories. The stories don't all occur in the Mojave Desert, in fact, many occur in Nevada and some occur in non-desert areas. It was the uniqueness of the Mojave Desert, however, that inspired me to start writing the stories.

Sunday, April 13, 2008

Back from the Middle of Nowhere

antelope I am recently back from a week-plus-long field trip in western Nevada. My first day gone was a driving day - I took some side roads and had to download my camera in my truck once during the trip because I took so many photos. I saw some interesting and strange sights along the way.

Pancake Summit
wolf Above: a "pit stop" at Pancake Summit on Highway 50 and lunch at the Toiyabe Cafe in Austin.

Middlegate Junction
Gabbs Above: I turned off at Middlegate Junction and drove through north and south Gabbs.

Pilot Peak
Walker Lake
Mason Valley
YeringtonI drove back roads through Gabbs to Mina and then to Hawthorne, which took me past Walker Lake and finally to my destination. Along the way, I made many stops for road cuts, old buildings, and expansive views. I'm now back at "our little house" with MOH after being gone 10 mostly long days. I have a lot of catching up to do in the next two days, including laundry, watering plants, and sorting mail. I have new boots to pick up, and - well, the list goes on beyond that. While I was gone, MOH was also gone part of the time, and was able to get to our non-outback home at the lake to relax, check things out, go shopping at one of those big box stores, grab some things from home to bring here, and also had time to visit with family. That is quite a lot for the two of us to have accomplished during the last couple weeks - besides a field trip for me and work for MOH. I'm not quite ready, but it's almost time to get back to work.