Weather Blowing Through

At least, I hope so!
The weather this month, so far, has been a bit variable (as weather often is), but it has been overall steadily deteriorating into wintry conditions. First, about a week ago, a little bit of ice appeared one morning - on my windshield and on the roof shingles of our little house - which I saw when I was about to head for work (photo above). No scraping was required.
A couple days later, there was still no snow on the ground except at the highest elevations. In the photo above, you can see what the early morning clouds looked like just after I arrived at work. Field work would have still be possible, but most everyone I know was indoors working on reports, maps, cross-sections, and last-minute year-end things, including the logging of any drill holes that were still in progress. I understand, however, from my forays into the current state of the industry at this year's Northwest Mining convention, that many drill rigs have been sent home early this year, and that it won't be difficult to come by drill rigs next year, in case you have some money saved up for ongoing or upcoming projects.
Just a few days ago, on Saturday, clouds and cold temperatures moved in, permanently it seems, bringing snow. It was cold when I arrived at work, and snow was falling on higher slopes in the distance (above), but lower slopes were still clear.
That all changed mid-day Saturday. By late afternoon, it looked like the snow was here to stay. In the photo above, the yellow and pink of the late afternoon sunset lights up clouds and snowy mountains, the same mountains seen in the previous photo. I drove home on snow-covered and icy to wet roads under partly cloudy skies.
Two days later, the snow was everywhere. It has been everywhere ever since. I went to work in the snow, arrived in the snow, and left in the snow. The photos above and below show morning SNOW! The snow was cold, light, and blew sideways, forming drifts behind my truck and lots of other places.

Today, it's been a bit of a different story, still cold, but sunny to partly cloudy most of the day. As you can see above, however, we did get a little new graupel on older snow.
I've spent the day mostly on the inside looking out, with MOH off to try out some winter camping and hiking. I hope it's not too cold! (I think snow and cold are part of the point, however.)

Geology is "Hot" because...

1. I get to climb around on rocks and balance myself in precarious positions.


2. I get to wear field boots,


3. and field sandals (see above).


4. I get to fly around in helicopters and stay out in the field all night when idiot pilots forget to pick me up.


5. I get to have a breccia collection.


6. I get to find v.g. (visible gold) out in the middle of nowhere (well, near Beatty, NV in this case).


7. I get to stop at roadcuts and look at rocks, which I've been doing at least since I was 5 (my first memory of a roadcut was from age 5, a particular slaty cut in eastern Nevada).


8. I get to have strange geology dreams.


9. I get to write geology poems and geology songs.


10. I get to find faults everywhere, and it's a good thing, not a bad thing.


11. I get to travel, even on days off.


12. I get to go mapping.


13. I get to find geology everywhere I go, even on vacation.


14. I get to work in the desert, with snakes and things.


15. I get paid to drive and paid to eat.

I get to know that subduction really happens, and that it has been happening for a long, long time. And I get to know that one really neat woman, the geologist and geophysicist, Tanya Atwater, contributed greatly to ideas of plate tectonics when those ideas were still being formulated. Her work, along with geological work done in, on, around, and over active and erupting volcanoes, constitutes part of my current definition of "hot" geological science.

Menard, H. W., and Tanya Atwater, 1968, Changes in direction of sea floor spreading. Nature, v. 219, p. 463-467. Reprinted in Plate Tectonics and Geomagnetic Reversals, p. 412-419, W. H. Freeman Co. San Francisco, 1973.

Atwater, Tanya, 1970, Implications of plate tectonics for the Cenozoic tectonic evolution of western North America. Bull. Geol. Soc. Amer., v. 81, p. 3513-3536. Reprinted in Plate Tectonics and Geomagnetic Reversals, p. 583-609, W. H. Freeman Co., San Francisco, 1973. Reprinted in U.C.S.D., Scripps Inst. Oceanography., Contributions, Vol. 40, Part 2, p. 1249-1271, 1970.

This post is being submitted for the December Scientiae Carnival, which is being hosted by Isis the Scientist, who loves Naughty Monkeys and Star Trek.

scientiae-carnival

Boots #1: Just Standin' Around

Well, I didn't have that much to write about (actually I have tons of things to write about, and tons of things to do), so I thought I'd just post a few pictures of geo-types standing around out in the field in their favorite footwear (oh, maybe that should be a friday footwear foto thingy). Mostly these are field boots or hiking boots, but some are tennies or lightweight hiking boots. As you can see, the geos are all standing on outcrops, which is one place geo-types like to be. The outcrops, all in Nevada of all places, are of 1) silicified rock, 2) unknown rock, 3) oxidized rock, 4) white tuff.

Breccia - A Popular Rock

Well, at least it's popular with me, and has been mentioned recently by a couple other geobloggers. As Andrew describes, breccias can form in many different ways - and he shows a picture of a breccia in an unknown rock (see comments) formed by unknown causes. Callan Bentley shows a breccia in limestone (his second photo), and he wonders if it might be a collapse breccia.

The breccias I photograph are often associated with faults, like this one, but it often is hard to tell what caused a breccia to form while out in the field. The breccias shown below were all found as loose rocks on a steep slope, a slope covered with lots and lots of breccia, probably not all formed the same way.
This breccia, which is the brownish portion to the left in the above rock, is a heterolithic breccia (more than one type of rock fragment) composed of white to gray, matrix-supported (the fragments don't touch each other), subangular to angular fragments in a brown siliceous matrix. The brown coloring is from iron oxides. The white to light brown portion of the rock on the right is dolomite, and it may be a large fragment in the breccia - but that is impossible to tell from this small rock - one would have to see the outcrop. I would suspect that this is either a fault breccia or a hydrothermal breccia, but would really want to see the outcrop before saying for sure.
The breccia above is monolithic breccia (one type of rock fragment) composed of mostly matrix-supported, subrounded to (maybe) subangular fragments of light gray dolomite in what appears to be a matrix of ground-up dolomite, or rock flour, suggesting that this is a fault breccia.
The above gray breccia is heterolithic, composed of mostly subrounded fragments of white to light gray quartzite and dark gray to black dolomite and limestone. I'm not sure if the funny-looking, almost white (cream-colored) fragment in the upper right of the rock is actually part of the breccia, or was something plastered on loosely. I didn't have all my geology tools with me (like my pocket knife). The gray breccia matrix is composed of smaller breccia fragments, angular to subrounded, in the gray carbonate matrix (limesone or dolomite). It's unclear to me what kind of breccia this is. It is strongly fractured by closely spaced fracture sets that are almost turning the rock breccia into a type of breccia sometimes called a crackle or crackled breccia. These close-spaced fracture sets can be seen better in the next photo of the same rock, below:

Here, above, is another breccia, with a field boot on top of it! This rock is almost not a breccia, being mostly a fractured rock to a crackle breccia. The fragments are sometimes not separated from the adjoining rock by more than a fracture, and the fragments haven't rotated or moved much from their original position, except, perhaps, in the lower right part of the rock. The dark gray to black fragments are clast-supported (touch each other), are subangular to subrounded, and are composed of dolomite or limestone.

In the lower left of the above photo, the black, fractured to brecciated rock is resting on a rock slab or outcrop of gray breccia. (Trust me, breccia is everywhere on this particular slope!)
The above rock, and the next, speak a little to the question of what were the rock holes seen in a previous post of mine. The light brown veinlets of silica and iron oxide stand out with respect to the somewhat weathered out black marble and marble fragments. These irregularly shaped to rounded-looking fragments may or may not have been rotated as in most breccias.
The above breccia is composed of subangular to rounded gray marble fragments, partly weathered out from the brown, iron-oxide-rich silica matrix and silica veinlets. At first, I thought the light brownish gray fragments, which are particularly shiny in the sun, were composed of pyrite or marcasite, but no, they are marble. There are a few square holes completely weathered out in the silica matrix where cubic pyrite crystals used to live. This breccia could be a tectonic or hydrothermal breccia, or some combination thereof - but, again, an outcrop rather than a loose rock on a scrabbly slope would be more helpful in determining the origin of the breccia, and so would a little microscope work.

More on fault breccias here - although the link goes only to an abstract, it does have some breccia definitions.

A Few More Field Days

OR: Just Another Day in Paradise
Shortly after the photogenic frost came, in fact, the very next day, rain came and made everything wet and muddy. Snow fell on the high and not-so-high mountains.
The resulting snow made the hills a bit inaccessible for field work for a few days... until the sun finally stayed out long enough to melt all but the highest snow.
More recently the days have looked like this: yellow-green juniper trees with a background of bluish green piñon trees. The afternoon shadows come early, and the low light seems to make everything brighter and more colorful.
Look closely: a couple juniper berries!
And then the sun goes down, slowly, creating even longer shadows, until nothing but shadow is left.

More on Endings

As Kim noted about a week ago, there have been some hints and threats of an ending field season going around, here and there in the west.
My first clue that the field season was ending, besides seeds falling everywhere, was some bright shiny frost I saw while driving to work one morning. I'm not sure it was the first frost, you understand, but it was a definitely photogenic frost.
Photogenic frost - on grass 'neath juniper tree - light and shade combined.
Later in the day, clouds moved in, making it difficult to tell one gray rock from another. A weak sun column (or sun pillar) formed in the west in the gray sky.

Friday Field Photo

Wandering around out in the hills a while ago, I came upon some old mine dumps. (I was in Nevada, after all.) The actual sources for the lower, larger dumps seen in the above photo are, as far as I could tell, up the hill: two smaller dumps you can barely see above and between the lower two dumps (click to enlarge). That is to say, the lower dumps are composed of waste material moved downhill from the upper workings by the oldtimer miners. Usually, that kind of transportation is done underground, but if any lower haulage adits (tunnels) exist near these lower dumps to connect to the upper workings, they weren't obvious, or were long-since caved in.

On one of the lower dumps, I found this interesting and colorful rock, an iron-oxide-rich rock with colors of brown, reddish brown, and yellow brown.

The rock has some large relict pyrite cubes in the upper left, and below that and cutting through the rock are some irregular veinlets of silica, which mark spaces where former rock fragments and former sulfides have been leached and weathered out, leaving holes and soft, punky, yellow and brown Fe-oxides. The host rocks to this oxide material is - limestone!

P.S. Any ideas about the diamond-shaped hole in the upper left below the relict pyrite cubes?

A Geological Haiku

Mahogany seeds

Over cherty limestone lie

A field season ends

This haiku is in response to a haiku meme started here.
The seeds are from the mountain mahogany tree, which is not a true mahogany.

Close Encounters: One Rattlesnake

ReBecca at Dinochick Blogs just started a wild animals in the field meme, following on our recent domestic animals in the field meme. Several posts related to that last meme included or featured wild animals, so do check that one out, also. ReBecca, Brian at Clastic Detritus, and Geotripper have an excellently large gaggle of excellent wild animal photos. UPDATE: Additional wild (to not-so-wild) animals can be seen at Magma Cum Laude, Geology Happens, The Dynamic Earth, and Crystallizations. ANOTHER ONE: Ron Schott has joined with wild and not wild animals. :D

I'm going to stick to one encounter with - a snake!
It's a rattlesnake, which I saw crossing the road in front of me one day last spring, and so I jumped out of my truck and immediately started taking photos as fast as I could. You can use the tire tracks in the photo for a crude scale, because I didn't have time - or the desire - to try to put my rock hammer next to the snake. I had to hurry with the photos: not only was the snake intent on crossing the road, as soon as I appeared on the scene, it became intent on getting away from me!

It's kind of small for a rattler, I think. It is most likely the western diamondback, though I don't know the many different species of rattlers very well

Here's the snake again, finally having made it to the side of the road, where it can now breathe a sigh of relief and disappear into the rocks and bushes.
Here, you can count the rattles on the end of the tail (which is, of course, where the rattles belong). I count 7, including the little tip. Folk lore would have it that the number of rattles are supposed to roughly equal the numbers of years a rattlesnake has been around, but a snake can shed it's skin more than once per year, which is when they grow a new rattle. So counting doesn't say much about the age of the snake.

This guy didn't rattle very much, which is one problem, in my opinion, with killing rattlesnakes that aren't near homes, camps, or ranches - I think there may be a chance that only the non-rattling rattlers survive - because it is the ones that give warning that are most likely to be killed by passing snake-killers - which will mean less warning the next time you get near one in the field. Consequently, I don't kill rattlesnakes unless they are in a place where they are likely to do some damage. I might have a different response to other species of poisonous snakes, but mostly haven't had to deal with any other kinds.

Dem Bones

I found a skeleton out in the field the other day. In fact, here and there I've seen a lot of animal bones - in one location the bones were scattered over an area about 50 feet in diameter, one rib here, another one there, as though a coyote pack had torn everything asunder. That one looked like a cow to me; this one is smaller, possibly a deer?
Here's a detail of what is left of the pelvic area.
Here's a detail of the skull, with large teeth and a pointy nose. Any bone people know what it is?

Sunday Driving

If you're looking for me...
...I'll be out for a Sunday drive.

Ice Breccia?

I found a little ice while driving into the field the other day, and being the first one on the road in the early morning, all the ice was intact from the overnight freeze.
This frozen pond was easy enough to go around, although I did manage to crack the ice a little while just barely skirting the right side.
This larger puddle was an entirely different story. The puddle straddles the entire road, and going off to either side would require driving into deep mud. The picture above shows what the muddy puddle looked like after I went right through the middle of it. I couldn't really see the thin coating of brownish ice over this pond, until I drove into it and heard it cracking (although it was cold, I had the window down). Some intact ice was left in a few places around the edge, notably on the far side.
The broken, angular ice fragments swirled around the muddy, somewhat turbulent water of the puddle - in an irregular to sub-circular, mostly clockwise, fashion. [The water wasn't at all turbulent, but just barely flowing beneath the ice, until I drove through and stirred things up.]
Then, some of the ice fragments washed towards shore on the side closest to me, forming a kind of ice breccia with angular ice fragments in a very fine-grained, muddy matrix. While out in the water, the fragments are matrix-supported. As they pile up on shore, they are more like a clast-supported breccia, but the watery matrix is gone, and the fragments are just resting on each other and on the grainy, muddy substrate, waiting for the sun to melt them.

The ice was all gone when I came back through later in the day.

Yesterday and Today

Okay, so that's not such an original post title after yesterday's "Yesterday..." post! So, I'm not so original, today. In fact, I'm just kind of making it through and wanted to post anyway.

I saw yesterday's wonderful pink, orange, and pale yellow sunrise through the bedroom window before I went to work. You can even see the screen, if you look closely. There are no storm windows or double panes in any of the windows of this old, little house. And though I appreciate being able to raise the lower part of the window on occasion, even during the cold part of mid-winter, cold air does seep through.

There is snow on the high mountains in the distance, and a few golden yellow leaves remain on the elms just outside the window. The fact that this is a sunrise and not a sunset picture is somehow cheering to me, and in fact I need some cheering and will take even that little bit!

The reason the photo is looking through the window and was not taken outside - well, by the time I was ready to leave, the sunrise was done! Amazing!

And that was yesterday, today's yesterday. Last night I came home, after a somewhat depressing day at work, to the warm smells of home-cooking, the warm company of MOH, and a couple soothing beers. Well, relaxing beers, anyway.

Tonight, after another day of making it through, I came home to this wonderfully cheerful sight - a new spot in the entryway of our little house, where we can sit down, under a bright light in an otherwise dark, cold, and electricity-free room, and take off our muddy, rocky, or snowy boots, before tracking all through the house and across the old, brown carpet. An arctic entryway!

I used it this morning, actually, and so my boots were warm from sitting all night on the boot warmers. The cheery thing about coming home to this - MOH had left the bright light on for me (he left for nightshift right before I got home, we passed each other on the road, so - don't worry - the light wasn't on that long!). It was fun to come in, sit down and take my boots off, put them on the boot warmers, and walk inside.

On the table I was greeted by two wonderful notes from MOH, both designed to warm my heart and to reassure me that all is well in the world.

Hopefully, that is truly the case.

Today and Tomorrow: On the Road Soon

The day dawned clear, with a nice pinkish glow in the east before sunrise. The weather is now warm - it was 36 F this morning warming to almost 70 - although snow is still hanging in there on the high slopes of the mountains around us.
Soon, like tomorrow, MOH and I will be at home, where everything is nicely arranged, and not very messy - because we aren't there all that often!
Hopefully, it will still be green, and hopefully our sprinkler system won't have given out for the third time in a row, and hopefully we'll see one or more of these in our backyard.

One nice thing about the schedule I'm working, is that I often get to leave work early the last day, sometimes by noon, today by 3:00. Also, Sundays are easier days, in which everyone can either come in late or leave early, and sometimes both. Often, the whole group of geo-types will go to breakfast, which then involves some slight sleep-in time, and a late starting time at work. Many places I've worked have offered time on Sunday during long work stints, sometimes as much as a half day - either to go to church if one wants to, to do laundry and such, or just to take a nice and well-deserved break.

As a kind of an aside, church is not thought of as something negative by many people I have worked with, and partly that's because many men's wives and their children often do the church thing on Sundays. I've only once seen this offer taken up by any geologist I've worked with, a young woman who is exceptionally good at running things and will be a major manager-type within a few years, by my estimate.

I'm really looking forward to these coming days off, and will probably stop here and there on the way to look at faults and other rocks, and then may take a short trip of my own after MOH goes back to work next week.

So, I'll be outside for part of Earth Science Week - you go outside, too!