Tuesday, April 27, 2010

The Unlikely Gradational Stratigraphy

I described the problem briefly in my last post about drilling at the Northumberland caldera: the volcanic formations and intracaldera units of waterlaid volcaniclastic and volcanic deposits — from the post-caldera Hoodoo Tuff, down into the intracaldera sediments, then into the caldera-forming Northumberland Tuff below — had sharp to relatively sharp contacts in the field. The chip boards from the previous year's drilling, however, showed gradational contacts from top to bottom — with Hoodoo Tuff chips present from the top all the way down, with chips of the uppermost unit 6 of the intracaldera sediments present from the beginning of unit 6 all the way down into unit 2 and below that into the Northumberland Tuff, and so on. At first examination of the chip boards, I simply didn't know what to make of the apparent change from sharp to gradational contacts, and thought that possibly it was the result of sloppy chip-board construction. Upon close examination, however, I finally realized that there were rock types from the top of the hole present all the way down to the bottom of the hole.

This kind of contamination is usually bad for sampling and assaying, but because we were looking for uranium, we were relying almost completely on a calibrated gamma-ray probe and not planning to do much assaying. Still, I wondered why the drilling was resulting in such strong contamination. The conventional answer, so to speak, was that we were using conventional rotary drilling, not reverse-circulation rotary drilling. Conventional rotary can easily result in contamination because the rock chips from the bottom of the drill hole come up the outside of the drill stem, and can pluck chips and material from rocks and formations above the bottom of the hole, all the way to the top. Reverse-circulation rotary drilling prevents this by having the chips go up the inner tube inside the drill rods, where the chips can have no contact with other rocks the drill has already drilled through.

I arrived on the Northumberland caldera drilling project, somewhere southeast of Austin, Nevada, and generally due east of Kingston Canyon — where I happened to be staying in a company-rented tiny cabin — in the fall of 1979. At first, we had a couple core rigs and one rotary rig running. I asked the rotary drillers how they usually did the sampling, and they told me that they usually laid out piles of chips and ground up rock for every 5-foot interval, in a nice line on the ground. Having been told to "ask the drillers," I thought, okay — odd, perhaps, but okay. After they laid out the chips in these nice, neat little piles, I was supposed to put them into the sample bags that I'd labeled. ("Hole 1, 0-5" or something like that; maybe we had a scheme, it's not one I remember.)

Now it's kind of awkward, even under the best of circumstances, to grab handfuls of piled, ground-up rock and somehow get them into 7 x 12½ white sample bags — and these weren't the best of circumstances. When I came back early the next morning to start bagging up samples from the first drill hole, I found the mounds of chips frozen into solid, cone-shaped piles, with the piles frozen to the ground. At first I kind of freaked, like OMG I should have done this yesterday, I am so screwed, etcetera. Yeah, the sun melted them later on — way after noon — but this sample-layout method really put a kink in things (at least for me). It was fall, and temperatures were prone to drop below freezing at night in the high valleys of central Nevada, suggesting that chip freezing would be an everyday occurrence.

I talked to the drillers and asked them if they could just put the samples into the bag instead of piling them up so neatly on the ground. They hemmed and hawed, indicating that they didn't *do* that. I told them we'd have to figure something out, because their on-the-ground method wasn't going to work unless my company was willing to wait around for next summer to get the samples. They finally agreed. I don't remember that it was hard to convince them, and I don't know whether they'd *done* that before, or were just trying to slip something by me. I have seen piles of chips lying out in nice lines as recently as 2005.

Okay, that problem is solved: the drillers are putting the samples in the bag. I'm numbering the bags — which is still a common but not always thing for a geo or tech to take care of — but they are sampling! Yay!

Now, let's watch what they are actually doing. On a conventional rotary rig, one that happened to not to have any kind of sampler or cyclone or splitter, the chips come up the outside of the drill pipe and just pile up on the ground around the hole. The drillers drill 20 feet of steel down at a time: that's the length of each piece of pipe. Every five feet, the helper (only driller and helper on the rig in 1979, not a third person for sampling) sticks a shovel into that pile and puts the stuff into one pre-labeled sample bag.

The pile around the drill hole just stays there, always being contributed to by more stuff coming up the outside of the pipe. Every now and then, when the pile is deemed too large by the driller, the helper pushes some of it aside with the shovel. I watch this process for a short while (having not seen it the day before), and eventually, between rods, tell them about the problem: every single rock type that has been drilled is still lying there in that pile every time the helper sticks a shovel into it to get the next 5-foot sample. Oh sure, the bulk of what goes into his shovel is the most recent stuff that came out of the hole — the stuff on the top of the pile — but not entirely. No wonder the formations glued to the chip boards from the previous year looked gradational.

I point out to them that they are taking a sample of everything that's come out of the hole for the last couple hundred feet, not just the last five. No, they insist that it's just most recent stuff, they are careful and just getting what is near the top. I tell them that it isn't really working that way, though, even if they think it is, and that I'd like them to clear away — with the shovel — that pile every five feet.

Well, no, they can't do that, they are on a footage contract and that would slow them down, having to stop every five feet to clear the pile away. They would be glad to clear the pile away every rod — every 20 feet. I tell them I really can't tell what the rocks are with all that stuff mixed together (although I sorta can, and the down-hole logs are diagnostic for many of the intracaldera contacts), and I tell them that the assaying will totally suck (although maybe we won't be assaying much of anything — and we didn't say "totally" like that back then, and maybe I used another cuss word, and maybe I hadn't fully developed my talking-to-drillers attitude or technique, which includes just the right cuss words at just the right time).

They finally agree that the helper can take a sample with the shovel, put the sample in the bag, then clear away all the rock debris that's piled up during five feet of drilling. It's not perfect, because the drill keeps drilling — or maybe it stops like it should, but I lost that bit of detail somewhere between then and now — but it's so much better, and the not-supposed-to-be-gradational contacts return to the clean sharpness that we'd mapped in the field.

And that's why you should never ask the drillers how to do the sampling.

And that's why it's a good idea to answer a young geologist's nagging questions, even if they seem really dumb to you.

And that's why you should have an hourly contract rather than a footage contract with your drillers: then you can slow them down anytime you want, and they can't bitch about it. (They might still bitch some, because a good driller wants to make footage, but a good driller should also recognize the importance of the sample he's getting.)

Friday, April 23, 2010

Drilling Stories: Getting Started at Northumberland

Last fall I didn't make it out to the high country, or much of the low country, before the snow fell, so I've left off the sequential history-of-exploration posts. I'll jump ahead to something in the future of the Caliente-camp stories already told, and also in the future of other summer-of-1978-camp stories that are yet to come in that timeline. And so, to where and when should I jump?

Because I'm low on photos, I think I'll tele-transport to a time and place for which I have few photos. That is, I have a few old pictures of drill rigs and people from that time, but I don't have many, and I have fewer still that might be crucial to explaining the stories. And so it goes.

Once upon a time, I was assigned to my very first drilling project by way of being reassigned from a project I was already working on (another story entirely). I inherited this already-in-progress project in the middle of my second summer at Northern Exploration Company from another young geologist who was no longer working there. I inherited chip boards from about 10 conventional (non reverse-circulation) rotary drill holes. Possibly no core holes had been drilled at that time; possibly a few had, but if so, I don't remember them. I do remember, in immense detail, staring at the chip boards from those several already-drilled holes, studying them, comparing them to the down-the-hole electric logs and gamma ray logs, trying to glean as much info from them all as I could, trying to reconcile the chip boards to the formations I knew well from mapping those same formations the year before (mapping was done by myself and several others), and trying to come up with reasonable and good drill sites with which to continue drilling.

— NOTE: Chip boards were used prior to the invention of plastic chip trays. We spent our days, while out on the rig, gluing drill chips onto strips of plywood that were designed to hang in warehouses after logging was complete. We made the chip boards on the tailgate of my company Bronco; each plywood strip may have shown 100 to 400 feet of drill hole, depending upon the space reserved for each 5-foot interval. The photo to the right is a different kind of chip board, made from small pieces of material left from core drilling. A photo of a rotary-hole chip board can be seen here in Figure 1.

Why was I staring at the chip boards so intently? Was there a problem? One problem was that the chips going down the hole showed a gradational stratigraphy from the upper formation, the tuff of Hoodoo Canyon, through several well-defined and distinctive intracaldera units, to the lower formation, the Northumberland Tuff. On the ground, these formations were easily distinguished, one from the other, and though faulting proved to be a problem in correlating stratigraphy between some holes, the stratigraphy was fairly simple.

Another problem? I couldn't seem to get anyone to tell me much of anything about running a drilling program. "Think you can spend this $500,000 by the end of the year?" Well, who can say no to a question like that? Uh, when is the drilling scheduled to start? In the fall. Is there time to spend that much money? Yes, but not without getting several rigs. Can we get permits for road-building and drill sites by then, can we get roads and drill pads built by then, and how do you go about getting permitting and flagging roads? Yes, yes, and figure it out yourself.

The project was almost unimaginably large to me at the time. I had never before seen a drill rig, and didn't know exactly what I would be doing out there. I knew I should be concerned about the sampling, and understood from my graduate Exploration Geology course that there were several sampling intervals and procedures that I should probably choose between.

Aside: A rock hammer lost in 1978 could be in this photo (above). If you spot it, let me know. On the other hand, it could have been washed away in the flash flood of 1979.

Finally, one geologist—slightly older and a couple years more experienced than me—told me to sample on five foot intervals. That's a standard sampling interval for this kind of drilling program, but everyone else had left me guessing, and it had seemed like pulling teeth to glean this minuscule amount of information. Others probably thought the answer was obvious, contained in the chip boards of the earlier drill holes. What about sampling procedures, numbering systems, and size of bags to use?

"Oh, don't worry about it. The drillers will know what to do."

We had a name for this syndrome—the incomplete question answering and lack of explicit instructions—long before the end of the first year (the Caliente year). We called it, "Give them enough rope so they can hang themselves." The they that might get enough rope for hanging was us; those who might give us enough rope were our bosses. I didn't invent the name for this syndrome (the name being the quote) . The name was invented by the geologist who had the drilling project before me—Jay, I'll call him—a male geo, slightly younger than me, who had been on our 1978 crew from late Caliente to Deer Lodge and onward.

Problem two, the sampling interval: solved. What about problem one, the unlikely gradational stratigraphy?

Wednesday, April 21, 2010

Questions about Drilling

I've been asked a few questions about drilling recently, so I'll attempt to briefly clarify a few things. First of all, not all my work entails drilling, though certainly many non-drilling phases of the exploration work I do is designed to create drilling targets so that we can find some ore. For a couple looks at what I do in general, refer to these two posts, and also browse the blog using some of the tags I use, or by using the search bar in the upper left corner (those are semi-efficient ways of navigating the blog).

The two linked-to posts are attempts to cover what I do, but they are by no means thorough, and they haven't been updated with more recent posts. Short version is this: I'm a minerals exploration geologist — my work ranges from generating reconnaissance targets, staking claims (that part is usually handled by staking or surveying companies) or aquiring properties through negotiations, property evaluation in general (which can include evaluating a lot of existing data or creating new data by sampling and assaying or by running various types of geophysical surveys), mapping the geology and generating drilling targets (or not, as the case may be), drilliing said targets and hoping to get the property past a first stage, on to a second or third stage, thence onward to the time when a property can become a mine and go into production. I've also helped evaluate companies (or their properties) as part of company acquisition negotiations.

As a minerals exploration geologist I've never been near an oil rig, nor have I worked offshore (although I'd like to visit an offshore rig). I've worked almost exclusively in metals, mostly in copper, uranium, and gold, not necessarily in that order. When I log chips, rather than core, it's called chip logging. I've never seen mud logging and don't know how it differs from chip logging, but the chips I log are washed clean of mud other than fault-gouge clay or alteration clay, and they have been sieved (through a large kitchen strainer) prior to being put into plastic chip trays that hold 20 intervals (usually 100 feet).

I almost never take drilling samples while running a drilling program, whether I'm the only geologist on the program or whether I have an assistant geologist (or partner) working with me. The drillers are supposed to do that — although when I first started in the business, one set of drillers was particularly poor at collecting the samples, so I gave them some training, while getting some training myself: it was my first project. I have more than one post in draft stage about this first drilling project.

I almost always work either with rotary rigs or core rigs. These typically are capable of drilling to a couple thousand feet or more, depending on the power of the rig and the depth of the target. When I started, reverse-circulation (RC) drill rigs were rare or non-existant, and so we used conventional rotary rigs. RC rigs are standard, now, for most non-core drilling.

When I first started working around drill rigs, it was customary to have two men on the rig: the driller and the helper. Now, RC rigs usually have three men, and core rigs often have two, sometimes three. I've seen one woman on a drill rig over the years: a helper (rod man) on a core rig. The third guy on the RC rig is specifically there to take the samples, and nowadays, to make the chip trays. It became standard to have this third person sometime during the 1980's. Prior to that, geologists may have taken samples in order to get good samples, and the geologist made the chip boards and later the chip trays (these were invented sometime in the 1980's).

I have rarely had to be at or "on" a rig the entire time it was drilling. Drillers usually work 12-hour shifts; I usually don't. Sometimes, when a rig is about to get done with a hole, but the target depth is flexible (not set beforehand), I will need to be there to "call" the hole, that is, end it. That can mean being at the rig until they quit in the evening (usually at 6:00 pm) and then, if the hole needs to keep going, also being there when they start up in the morning (usually at 6:00 am). With a single 12-hour shift — which is more common on exploration rigs in the middle of nowhere than on rigs near mines, but is by no means standardized in either locale — I've usually not had to be there every morning at start up and every evening at shut down. I've often been able to run myself on a ten-hour day.

The only drillers I've seen that worked less than 12-hour shifts (more like 8 to 10), have been drillers on rigs that are more typically used for environmental-type drilling, such as what Short Geologist might be describing here.

Many RC and most core rigs will run two 12-hour shifts, in which case a geologist might be required to answer a cell phone in the middle of the night, although I've done that only rarely. A 24-hour rig will often need to have more than one geologist around, trading off night calls and other tasks. It's often possible to let the rig drill through the night, barring unforeseen and usually undesirable circumstances. Back in pre-cell days, if a rotary rig was running two shifts, a geologist might have had to go out and visit the rig if it looked like it might need down-hole logging or "calling" in the middle of the night. I did that a couple times a long time ago. Core rigs, which have usually run two shifts, don't generally need to be visited in the middle of the night because their drilling rate is so much lower than rotary rigs, usually a third to a tenth.

I hope that covers some of the questions I've been getting, both here on the blog and via email. My recent post about drilling was probably somewhat vague.

UPDATE (4/21/2010): Be sure to see Short Geologist's most recent post about drilling, for a look at what she does.

UPDATE (4/23/2010): Chuck posted a link to a neat, back-of-truck, core-logging setup he used last year. My trucks aren't usually that large!

Related Posts:
Drilling Stories: Getting Started at Northumberland
The Unlikely Gradational Stratigraphy

Monday, April 19, 2010

Here's to You, Geological Heroes

The Accretionary Wedge is coming up soon, so my thoughts are naturally turning to Geological Heroes, the topic of this month's Wedge, hosted at Mountain Beltway by Callan Bentley. Callan says,
I invite all participants (geobloggers and geoblog readers alike) to contribute stories of their heroes. It’s time to pay tribute to the extraordinary individuals who helped make your life, your science, and your planet better than they would otherwise have been.

As far as geologic heroes go, I was first thinking that maybe I don't really have any (or maybe I just don't have many personal ones that I feel I can write about on the blog). I thought, therefore, that I'd list two geologists who are heroes to me, although they aren't personal heroes:
  • Tanya Atwater - a leading plate tectonicist, geophysicist, geologist, and oceanographer. She is a hero to me by way of being a leading and famous woman in my field (or a related field), one who "is especially well known for her works on the plate tectonic history of western North America, in general, and of the San Andreas fault system, in particular... ."

    I've not yet had the good fortune to meet her, but long ago (and not very far away) I named a dog belonging to my previous partner and me after her. Upon hearing of this dubious honor from an acquaintance of ours, Tanya A. reportedly said, "Ruff ruff," while making a motion like scratching her ear with a paw.
  • Tom Dibblee - a legendary field-mapping man, who mapped "565 quadrangle maps covering over 40,000 square miles, some fourth of the State of California." I first learned of his mapping while working in the Mojave, where his maps cover nearly every square inch of ground and provide the basics and details for every geological map that has come after him. He is known in that region for not having to use a Brunton to take strikes and dips (except when beds were dipping at shallow angles), because his sense of orientation and angle estimation were excellent, such that he was always within a couple degrees. He started mapping when in high school, and never stopped, completing a mapping career of almost 80 years only when he passed away in 2004.
    Beyond these two, I was sitting out on the rig one day, and while thinking that I'd just leave this post at a two-person list I realized that the topic "Heroes" was making me think of Waylon and Willie, and I started singing "Mamas Don't Let Your Babies Grow Up To Be Cowboys."

    Don't let 'em pick guitars and drive them old trucks...

    [technically a road song because it mentions trucks] and then that somehow led me into "All My Heroes Have Always Been Cowboys" followed by "Waylon, Willie, and Me."

    Now, not all the lyrics of these three songs are applicable to whatever particular feeling they engendered in me on that recent field day, nor are all of the lyrics particularly applicable to the topic of geological heroes — except that:

    When I start thinking about the real geologist heroes I've known over the years — whether male or female — they are rather much like cowboys, or like outlaws: out in the field all day, bouncing around in pickup trucks old and new, doing their own thing, making it on mottos such as "it's easier to get forgiveness than permission" or "it's all changed now," running their own programs, districts, and companies, shooting cans, rolling boulders, and participating in other shenanigans that shall go unmentioned here, some of which have involved various forms of (legal in Nevada) explosives.

    These more personal heroes of mine include my thesis advisor(s), my major professor, the professor I T.A.'d for, several former professors and T.A.'s, many geologists from both Northern Exploration Company and Former Mining Company and elsewhere, the two Larry's, the two Nancy's (you *know* who you are), most of my former field assistants — one has or is now running her own company, one patented her Hg-gas sniffing method and has run her own lab, one is now running her own exploration group at a major mine, and some have gone on to other things but are nevertheless heroes to me for making it in the "man's field" of exploration and mining geology.

    My heroes, over the years and decades, have also included several FOP/Quat people: JODavis, Bud Burke, Marith Reheis, and anyone who was present for the flying Vee in the middle of the Black Rock Desert in 1987 or who made it to the 1991 FOP down in Fish Lake Valley, Nevada.

    And then there are some true outlaws or aspiring, wanna-be outlaws — hmm... should these names go unmentioned? (You know who you are: R, BS, JS, PG, S+D, et al.)

    Really, when it comes right down to it, there are too many geological heroes to list, refer to, or name, including all the consultants and independents attending the hospitality suites and receptions at Northwest every year, going back to the wild S+D bashes in Spokane some thirty-plus years ago.

    And so, here's to you (all of you)...

    ...from a copy of a print from an original slide taken here at a now burned-down hot spring cabin, by JODavis in the fall of 1981, photo credits to JODavis and LLLackey, photo ©2010 Looking for Detachment, all rights reserved, poem written by SH and CR.

    The Spencer's Hot Springs cabin, with roomy concrete bathtub and piped in hot water, was burned down later that year or the next, reportedly by the same individuals who, in their over-zealous righteousness crossed out in red marker the name "Asshole" (and other cuss words written on the interior of the cabin) — these individuals were apparently disturbed by the existence of such a den of iniquity as a hot spring where people *gasp* sometimes bathed naked. I don't know who these red-marker people were, nor do I really know that they were the arsonists — but that's the way the story goes.



    The original from the 1978 album "Waylon and Willie."



    A live version probably recorded in 1990.

    April 2010 Accretionary Wedge: Heroes

    Saturday, April 17, 2010

    Rig Sitting in General

    I've been in the field recently — in an unspecified location — and every now and then I think of things to write for the blog, or photos I could post, but it's often been either too windy — or sometimes too snowy, or too windy and too snowy at the same time — to write anything down. I am able to write field notes in my field book: field books don't blow away, and Rite in the Rain books don't run or get messy, especially if one uses a Rite in the Rain pen. In fact, it's been mostly too windy to work on the field-based cross sections I've started.

    And why would I even have time for writing? Whether an in-field, drill-sitting geo has time for cross-sections, paperwork, mapping, air-photo mapping, report writing, or other writing depends on the setup of the drilling program. For some types of projects, the drillers don't fill little twisty-tie sample baggies for me, nor do they always make chip trays. When they do, I can examine the contents of the baggies filled with rocks, chips, or other material at some distance from the rig, or I can log the chip trays on the tailgate of my truck (or in the cab, not really preferred unless the weather is completely nasty : or in a core shack or office). There are some advantages to watching the drilling as it goes down (so to speak), especially on a smallish project or a project where one is still feeling out the sampling methods or drilling company. If I'm present, I can observe the drilling recovery first hand, for example, rather than relying on the driller's reports (daily logs).

    Because of the logistics of the current project — which I won't describe — I'm unable to sit in the cab of my truck at some distance from the rig, away from the noise and diesel exhaust. Consequently, I'm wearing my PPE, which includes ear plugs, hard hat, and boots. Retreating from the rig to some distance is my preferred method of sitting a rig, if indeed a rig needs sitting. Not all rigs do. They generally need to be checked on now and again, and samples need to be picked up (by techs or geos), and occasional troubleshooting or budget watching is usually necessary — but those things don't always require full-time rig sitting.


    Thursday, April 15, 2010

    From the Field: Reflection and Refraction

    Just a quick photo grab of something seen in the field the other day. Reminds me of Snell's Law - and for all those who doubt it [looking at you, long-ago engineer in Philosophy of Science class], anisotropic media are far more common in the mineral world (and nature in general?) than isotropic media.

    Monday, April 12, 2010

    From the Field: Snow Wheels

    I saw these snow wheels (or are they called sun wheels?) a few days back while out in the field.
    They typically form on sunny afternoons when the snow starts rolling down talus slopes. This rocky slope (above) has several, best seen from a different angle (below).

    Many of these aren't perfectly round, and I saw at least one that looked more like a small roller (think steamroller) - wider in the horizontal dimension than in the vertical dimension.

    I didn't find much written about these, but did find some excellent photos on Flickr.

    Friday, April 9, 2010

    Things You Find in the Field: Stingaree Valley

    One wintry day a couple years ago, I stopped alongside the road - Highway 50, that is - in Stingaree Valley, the "Earthquake Faults" valley, between West Gate and Drumm Summit (over the north end of Fairview Peak). That's Chalk Mountain in the right middleground, with Dixie Valley and the south end of the Stillwater Range beyond that.
    Part of an old soda machine.
    Other miscellaneous metal items, all shot up during target practise.
    An abstract wire sculpture.

    There's a lot of old stuff lying near the road in Stingaree Valley. Perhaps we'll see some more of it someday. :)

    Wednesday, April 7, 2010

    The Way it Went Down

    It all began - at least for me - on April 6, 2009, when MOH and I were driving toward Susanville on Highway 36. Note the shovel hiding behind the tree.
    The entire roadcut was barricaded off, and fearing the worst, we pulled over so I could take some in-progress pictures.
    I climbed over the barricade...
    ...and quickly grabbed a few close-up photos, just in case they were planning to take out the entire exposure...
    ...and just in case all my other close-up photos of the roadcut might be non-digital, which is what I suspect.
    On May 18, 2009 - the 29th anniversary of the eruption of Mt. St. Helens - the destruction of this fine roadcut had continued, and it was clear that it would be wiped out.
    On July 29, 2009, we pulled over again. Roadwork had moved farther westward on Highway 36, and the roadcut with the excellent baked zone (among many other great geologic features) was in its now current form.
    There's really not that much to see anymore, especially when compared to what one could see before.
    I didn't even walk over to the other side of the road.

    Does anyone knows what basalt this is - possibly the Miocene Lovejoy Basalt or the Pleistocene basalt of Susanville Peak?

    Related Posts:
    Susanville Roadcut Before and After
    Baked... Lake Sediments?

    Monday, April 5, 2010

    Susanville Roadcut Before and After

    Photo credit: Alaska Al

    Back to the destroyed roadcut near Susanville, CA. The original roadcut, seen above in a picture taken by Alaska Al on one of his many travels here and there, inside and outside Alaska, can be viewed presently in Google Street View, but don't count on that lasting.

    Here's a composite view of much of the outcrop taken on June 3, 2008.
    This composite view, nearly matching the above view, was taken July 29, 2009, not long after the SanFran geoblogger meetup-tweetup.
    As you can see, in this more complete composite view, there isn't nearly as much to see as there was prior to massive digging, dozing, and scraping of the formerly fine roadcut. :(

    Saturday, April 3, 2010

    In the Field Again (Take Two)

    Yes, I'm in the field again, as many of you have gleaned from here and there (and elsewhere) updates and postings.

    The field in this instance is a fairly short drive from our little house in the hinterland of eastern Nevada, and the field is an all-day outdoor affair. Although I nominally work a 10 hour day, with drive time and meetup-with-the-drillers time, it's more like an 11.5 hour day on many days, less on some, more on others. I'm left with scant time for blogging and other communication, but we'll see how it goes. I have some drafts that I might be able to post, and possibly I can post some other things depending on evening, morning, and weekend time.

    I've been working an unusual 6 on and 1 off schedule, modified this week to 5 and 2 in honor of the Easter weekend. With the extra spare time, I'll be able to drive MOH to his winter mountaineering area without having to leave at 5:00 in the morning. I'll also have enough time - I hope - to get my taxes done.


    Reminds me of a song:
    In the field again, I got to get back in the field again, the life I love is in the field with my friends...

    Friday, April 2, 2010

    Baked... Lake Sediments?

    Just a quick preview of a roadcut on Highway 36 near Susanville, CA, showing a basalt flow over some white [probably tuffaceous] lake sediments. The reddish baked zone may might include subaerial deposits.

    And a closer view:
    This roadcut was heavily modified in 2009; the exposure now totally sucks.

    More on this later...

    UPDATE (3Apr10): This post was inspired by Callan Bentley's post on Baked fanglomerate at his (relatively) new blog Mountain Beltway. I thought, perhaps, that posting another baked zone would result in a meme that would propogate through the Geoblogosphere, but so far it's a mini-meme of two. :)

    Andrew Alden, About.com:Geology, has a great geological wallpaper of a similar baked zone near Alturas, CA - check it out! I wonder if the two roadcuts are expose the same basalt flow.

    UPDATE (4Arp10): More geobloggers have joined in this geomeme, Ron Schott has a baked contact (?) on a green sand beach on Hawaii, and Kyle House has a photo of a baked carbonate soil in colluvium on the Owyhee River.