NOVA Geoblog

The shape of things to come

2010-02-15T08:00:00.006-05:00

This is the final post on NOVA Geoblog. From here on out, all my geoblogging will be done at a new blog, "Mountain Beltway:"

I have also started a new "announcements only" blog, which I've given the breathtaking name of "D.C. Geology Events:"

If you're in the Washington, D.C., metropolitan area and you want to keep up on what's happening at venues like the Carnegie Institution or the Geological Society of Washington, I would invite you to subscribe to the D.C. Geology Events feed. Every time I find out about a talk or a field trip or a museum exhibit opening or whatever, I'll post it there. I'm also recruiting other D.C.-area geological cognoscenti to serve as co-authors on D.C. Geology Events. So far I've got two people to help out by posting stuff there. So, dear reader: if you are a pipeline for information about seminars, etc., and want to be able to post your events on D.C. Geology Events, please get in touch with me, and I'll add you to the blog as an author.

Why this change, this "avulsion" of my blog flow? There's several reasons.

Blogger decided to stop publishing via FTP. I composed NOVA Geoblog on Blogger, but then published it to the NOVA servers. This was always problematic -- NOVA makes me change my password periodically, and it was difficult to keep Blogger in sync with it, resulting in many frustrating instances of failing to publish when I tried to, and then it shutting down my NOVA account access (which automatically locks after three unsuccessful attempts to log in). Blogger found it a pain too, and decided to stop dumping so many resources into supporting FTP. Fair enough. Turns out I'm happy enough to switch away from Blogger for a couple other reasons, too.

I always hated the limits Blogger imposed on my typography. I'm an advocate of the old Chinese aphorism that "The beginning of wisdom is to call things by their proper names." Unfortunately, Blogger cannot seem to handle things like accent marks, tildes, degree symbols, and the like. This is a bummer. Even things like long dashes and curly quotation marks turn into garbled code mess when copied and pasted into Blogger. ("Copied and pasted" because you sure can't type them in directly.) So Blogger limits users that way.

I started this blog as a way to communicate a stream of news items and web resources to my students. Soon after I started publishing it, though, other people discovered it, and now that extended global audience is primary in my mind as I am writing. I think re-inventing the blog as Mountain Beltway will allow me to directly serve that readership with less NOVA-flavored ambiguity. Fortunately, there is a new tool that allows one to transmit links to cool web resources with a minimum of infrastructure: So, I've decided to join Twitter, and import my Twitter feed into the sidebar of Mountain Beltway.

Along similar lines, a clear issue with NOVA Geoblog is that I'm very much a local boy with a lot of interest in engaging with the local geologic community. Hence the frequent announcements about seminars, talks, meetings, etc. Mountain Beltway will be written from a D.C. perspective -- the name itself conveys that, I hope -- but it will be free of all "locals-only" meet-up information. That's what D.C. Geology Events is for.

Because NOVA Geoblog is hosted on servers owned by the Commonwealth of Virginia, the same people who employ me, and I never got official permission to blog on our webspace, I was always a little worried that someone would get upset with something I wrote, and get in touch with my bosses and shut me down. There are plenty of cranks out there, and plenty of lawyers to back them up. If I'm blogging on my own, and it's hosted by WordPress, that's no longer as acute an issue. I suppose it's worth disclaiming that there, as here, my opinions are my own and do not represent Northern Virginia Community College, the Virginia Community College System, or the Commonwealth of Virginia.

To shake things up a bit. While NOVA Geoblog hasn't gotten "stale," exactly, I've definitely gotten a charge out of inventing Mountain Beltway. I'm excited to do some cool blogging there. In fact, I've been so motivated that I've already written the next ten posts that will appear there -- but I'll parse them out over the next ten days. So much for my plans to blog less, eh?

I got some great feedback in the survey that I blogged about yesterday, and one of the things I'm keen to do is engage in more discussion with other geobloggers and geoblog readers. Ever since my 1000th post, I've noticed an increase in the tempo and diversity of commenting here, and I'm grateful for it. I've also made more of an effort myself to comment on other blogs, and also to respond to comments here, even if they don't explicitly require a response. I've enjoyed the discourse: it's fun. Thanks to all who have participated. I envision a similar lively back-&-forth at Mountain Beltway.

I'll leave comments open on NOVA Geoblog for 1 more week, then shut them down, too.

I set the new blog up a week ago, so you'll find some content waiting for you. See you there.

Linguoid ripples in snow?

2010-02-14T14:32:00.001-05:00

Georgia Perimeter College professor Pamela Gore sent me these photos yesterday of some interesting structures she found in the snow in her yard. She was away for the storm itself, so she didn't watch them forming, but the morphology suggested linguoid ripple marks to her. If that's accurate, the current direction (wind direction) was from the north. Take a look at her photos below, and here's some photos for comparison.

Two shots that are zoomed and cropped from the image above:

Pamela e-mailed me again this afternoon to say that, "Looking at them in daylight, they look like they were formed by impacts of snow [clumps] from trees, landing at an angle and causing folding on the 'downstream' side."

What do you think? Are these linguoid ripples? Any sedimentologists want to chime in?

Survey results

2010-02-14T07:43:00.011-05:00

Thanks to the 88 of you who took the time to complete the short survey which was posted a couple of weeks ago here, concurrent with the 1000^th post.

I wanted to share the results with you today... as a prelude to a major announcement tomorrow.

The first question attempted to gather demographic data about my readership.
Of the 88 respondents, there were...

9 friends of mine
4 NOVA students of mine
6 GMU students of mine
1 undergraduate student at another Virginia school
5 undergraduate students at a non-Virginia school
1 graduate student at Virginia school
7 graduate students at a non-Virginia school
14 university faculty
6 two-year college faculty
6 high school Earth science teachers
27 professional geoscientists
28 amateurs who are interested in geology
21 residents of the greater Washington, D.C. metropolitan area
3 former residents of D.C. area
21 geobloggers
6 non-geology bloggers
60 U.S. citizens in the U.S.
1 non-U.S. citizen in the U.S.
2 U.S. citizens residing abroad
14 non-U.S. citizens, residing in their home countries
5 Libertarians
3 Republicans
13 politically-centrist folks
34 Democrats
42 Liberals
12 who don't consider themselves political at all
0 young-Earth creationists
2 old-Earth creationists
4 who describe themselves as "very religious"
6 who describe themselves as "moderately religious"
34 who describe themselves as "not religious"
14 who describe themselves as "spiritually inclined"
22 who describe themselves as "agnostic"
27 who describe themselves as "athiest"
63 avid readers
50 avid Internet surfers
13 avid television watchers
6 hermits
50 males
33 females
1 chemist (write-in response)
1 environmental activist (write-in response)
1 newly retired marine biologist/science editor (write-in response)
1 retired widower anti-Church Californian (write-in response)
1 fan of post-modern formalism (my favorite write-in response!)

Analysis: That's about what I expected. I thank everyone for sharing this demographic data.

The second question asked people why they read NOVA Geoblog. The responses (click here to read them all, then "BACK" to return to this post) clumped together into several major themes:

Diversity of topics presented (7 responses)
DC-area affinities (9 responses)
Travel stories (12 responses)
Teaching ideas (12 responses)
Writing style (22 responses),
...described variously as clear, instructive, balanced, and enthusiastic
Topics being discussed (25 responses)
Illustrations, including photos, including annotated photos (28 responses)
Several people also mentioned these topics: the Patagonia series, virtual field trips, current events, and "fun!" One person comes here for environmental stuff. One comes for practicing their English skills.

Here are a few responses to the "why I read this blog" question that stood out to me:

"I appreciate the way you integrate all different levels of geology content quite seamlessly into your posts."
"I like the genuine enthusiasm for geology/nature and life that Callan presents. The blog is honest and upbeat."
"It's probably the geoblog from which I learn the most, in the sense of gaining new knowledge and skills, above all the skill of looking carefully and understanding what I see."
"[I] wonder how I can grow up to live the Callan Bentley lifestyle. ;-)"

I also asked people what they liked about NOVA Geoblog. Here's a little graph showing the number of responses to the proposed answers I gave as options:

But I also had a space for "other" answers, and several people availed themselves of that opportunity. Among the "other" responses were:

Geopuzzles / me posing questions for readers
Reiteration of the popularly-noted choice above: the photos, travel photos, annotated photos, and illustrations.
Timelessness. Here's a quote: "I like the fact that I can read and re-read the entire 1,000 entries. It's an education in itself, and a great resource. Case in point: last Autumn as I hiked in the Sierra Nevada I recognized boudins in a rock formation. I would never have known what they were if I hadn't learned about them from your blog. Thanks for enriching my adventures."

Analysis: The geological content is the driver for this blog. I'm blessed/cursed with 'geology-colored glasses,' and a compulsion to share my interest in geological topics. That's the main reason I write, and the main reason readers read. Additionally, people really seem to like the way I do photos, annotations and illustrations. So do I! As a visual learner, I'm pleased to have some reinforcing affirmation there. I promise to continue that trend into the future (major announcement tomorrow about what the future holds).

If I'm going to ask about pros, I should also ask about cons; so I did. Here's the graph accompanying the question "What do you dislike about NOVA Geoblog?"

Less of a response here, probably not surprisingly. In the "other" category, we had the following items of feedback. My responses are in brackets, italics, and red type.

a lot of "there's nothing I dislike about it" (16 out of 36 "other" responses) [CB: Cool. Thanks.]
"I view blogs as personal diaries and as such I don't find much to dislike about a particular blog. If I don't enjoy the presentation of information on some level I simply stop reading the blog. This isn't the case with NOVA Geoblog. I think there is a diverse range of subject matter presented here and therein lies its value. I'm not always interested in the material and I don't always agree fully with the analysis, but I probably wouldn't be a geologist if I did. For myself, the point of reading a blog is to be aware of the scope of interests of other geoscientist in the world and NOVA Geoblog achieves this aim." [CB: I welcome alternative interpretations of the rocks or geologic systems that I write about. Chime in via the comments section!]
"It could be better organized, using tags & categories to make posts on particular themes easier to find." [CB: Point taken. You're right. This will be solved with the changes I unveil tomorrow.]
"This blog is well-balanced like perfect hoppy beer." [CB: Cheers!]
"It's not really about NOVA." [CB: Not all the time, no. The title wasn't meant to convey that all the content would be NOVA-focused, just that's where I'm writing from.]
"Callan (you!) often writes with the tone of voice of a DC native, i.e., a Beltway insider. To change that you will probably have to live in other places for a few years. I suggest a mix of rural areas, small towns, small cities, and big cities in Mississippi, Wisconsin, and New York." [CB: Hilarious! I've lived in Arlington and Williamsburg, Virginia; Martinsville, Indiana; the San Bernardino Mountains of California; a remote village in Mongolia (Ereentsav Sum, Dornod Aimag); the San Juan Islands of Washington; Homer, Alaska; and now in urban Washington, D.C. I've also spent the equivalent of several months apiece living in the high Sierra of California, and in Bozeman, Montana. I'm quite literally inside the Beltway these days, and doubtless I write with that perspective -- but I'm not lacking in experience of living elsewhere. Furthermore, I've got my dream job in a geologically-interesting place, surrounded by people I love. Unless something fundamental were to change, I'm not moving anywhere anytime soon.]
One person complained about the survey: that some of my questions were flippant, or that they could not imagine how they could be relevant. Specifically, they took issue with some of the demographic questions in Question #1 about U.S. citizenship and the "hermaphrodite" option. In response, I would say: I was just curious, that's all. Sorry that my asking offended you. As for "hermaphrodite," I was just trying to keep the mood light. My bad.
"Not really a complaint specific to this blog, but sometimes comments/questions posted in the comments section are left without response, which is somewhat puzzling in light of the professed desire for more comments. Lack of response to legitimate questions or remarks aimed at generating further discussion of an interesting topic (of course flames/trolls and spam are not to be encouraged) tends to discourage further commenting, and makes the reader think that the blogger is indifferent, or perhaps only interested in receiving praise--which raises a good question: what do bloggers want or expect to receive in their comments sections?" [CB: This is an excellent point. I am fully to blame for leaving legitimate questions hanging without a response. There are two specific examples that come immediately to mind: a twice-asked question about Ordovician glaciation evidence in the mid-Atlantic region, and a question about whether the Michigan Basin could be a bolide impact crater. Both of these comments continue to sit (fermenting?) in my e-mail inbox, as I wait for a time when I can compose a full, thoughtful response, including doing additional research about the Ordovician glaciation question. As for other questions 'left hanging,' I take the full blame, and I intend to change my frequency of commenting. In fact, I've been both commenting more, and getting a lot more comments, since the 1000th post that kicked off this self-reflection and request for feedback.]

Analysis: The prime complaint is one I anticipated: that the DC-area announcements were wearing thin on non-DC-area readers. With tomorrow's announcement, I will solve that problem. The complaint that struck home most forcefully with me is the last one in the list above, about the comments. I resolve to respond to all legitimate questions on the blog, and if I don't have a ready answer, then I'll use my response to say so.

Finally, and most prosaically, I asked how often people visited the blog. Here's the graph:

There were a few "others" here, too. They specified which RSS feed they used, or said things like "a few times a week." Nothing shocking there.

Analysis: The majority of people who read this blog either make it a daily habit or automate the habit via an RSS feed. If you haven't yet learned about RSS (Really Simple Syndication) yet, allow me to advise you: You really, really should. It's Really Simple. I recommend setting up an IG page with your Google account, and importing RSS feeds there. Alternatively, pipe them into your Google Reader account. It's quite simple to set up, and the best part is your computer will do all the work for you, scouring the web for the latest, and bringing it to one single page, where you can then view it. For instance, I personally subscribe to 183 separate blogs via RSS. Some update several times a day, others once daily, others sporadically. As far as I'm concerned, I no longer have to care about how frequently they update. If there's something new, I'll see it. If not, I don't have to think about it. With the RSS, I can be confident that I'm not missing anything, and I don't have to invest any effort or time seeking out the content.

Thanks everyone for all the feedback. I sincerely appreciate it. Tomorrow I'll reveal the future of my blogging.

Bill Burton does EPOD (Redoubt)

2010-02-13T07:40:00.002-05:00

Last year's president of the Geological Society of Washington, Bill Burton of the USGS, is the author of today's Earth Science Picture of the Day (EPOD). It shows Mount Redoubt erupting an ash plume amost a year ago. Go on over and check it out.

New geoblog with a GREAT title

2010-02-13T06:40:00.005-05:00

Via the comments on my Bob Hazen book post, I found George D. Turner's thoughtful, fun geoblog Eclectic Plagiodoxy. You know I'm going to be intrigued by a title like that. Here's the beginning of George's explanation of that polysyllabic wonder of a title:

The word "plagiodoxy" came to me in a familiar place: in front of a classroom of introductory geology students. I was trying to connect the sometimes arcane jargon of the science with ordinary experiences the students were familiar with. In this case, I was working my way through the mineral group called feldspar, trying to make semantic connection with the two sub-groups, orthoclase and plagioclase. So I was chatting about ortho-dontists, ortho-pedists and ortho-doxy. I ended up saying something like "I suppose if you wanted crooked teeth, you would go to a plagiodontist. If you wanted crooked bones, you would go to a plagiopedist. If you wanted to learn to think on the slant, you would go to a plagiodox institution. That's called 'college'."

Go and check out the rest -- I think I like the way this guy thinks!

2-year college geoscience departments: Workshop to be held at NOVA

2010-02-12T09:29:00.002-05:00

If you're a geology professor at a two-year college (community college, junior college, etc.), then please consider attending a planning workshop June 24 to 27 here at my campus of NOVA. My department and I are hosting, and the talented crew at SERC, including Heather MacDonald, are organizing. More details at the SERC website.

"Genesis" by Bob Hazen

2010-02-12T09:25:00.003-05:00

Book month continues...

Over the Snowpocalypse, I read Bob Hazen's book Genesis: the Scientific Quest for Life's Origin. Hazen is a celebrated and charismatic scientist whose primary gig is at the Carnegie Institution of Washington, though he is also the Clarence Robinson professor of geology at George Mason University. (He's also the guy who got some time in the spotlight the year before last with his ideas about mineral evolution and one of the team manning the Carnegie's new initiative the Deep Carbon Observatory.)

The book is an insider's account of what insights science has gained into how life began on our planet. Spanning several decades and labs on three continents, the story is ultimately one of chemistry, and of people. The chemistry is the knowledge part of it: how did life's fundamentals (metabolism and genetics) come to be? We know a lot about how to put together polymers from smaller (and presumably abundant) monomers, and we know a lot about the rawest forms of both metabolism and the passing on of genetic information. But there is a gap, progressively narrowing through dogged science, which we don't understand. The book is very much about famililarlizing the lay-reader with the details, and limits, of our understanding.

It is also very much a book about scientists, the people who get science done. This is probably the more interesting part, at least to me. Some of the stories Hazen tells are insightful and endearing, as you get to observe major breakthroughs through the biographies of those who made them happen. There are also bizarre twists, like a debate between Bill Shopf and Martin Brazier in 20002 about the ALH 84001 meteorite, the one purported to hold fossilized Martian microbes. I'll leave the details for the reader to discover, but it sounds like a very uncomfortable scene. Also on the 'people' angle, I found it interesting to hear when Hazen was pursuing an interesting new angle, and was asked politely to stop by a colleague because the colleague had promised someone else the chance to test that particular hypothesis. Navigating the politics of research is something I don't have a lot of experience in, and so I found this intriguing. Similarly, the story of Nick Platts and the PAH World hypothesis was a neat case study in how science can work -- albeit more dramatic and "Eureka!"-ish than the usual lab monotony. Finally, I really enjoyed the flavor provided by Hazen's anecdotes about life around the Carnegie: beers, volleyball, crowded lab space, small stories about the people who I see at GSW.

Hazen's own contributions to the field are mainly centered on the high-pressure, high-temperature lab experiements he does in the "bomb" at the Carnegie, and his expertise on minerals as a geologist. He does element mapping of fossils, and experiments to see if mineral surface chirality can 'select' for 'left-handed' or 'right-handed' amino acids. This is definitely not the centerpiece of the book though: to his credit, Hazen shows himself to be but one scientist in an active, vibrant field. His contributions are presented with equal weight as compared to his peers' and colleagues' contributions. I think it's well balanced that way. He also pulls no punches when it comes to odd, demeaning, or outright political behavior on the part of his peers, and I can imagine that some of them would have issues with the book on that count. It seems to me that he tells it like it is. Reviews on Amazon are mixed, but mostly positive, with the main criticism apparently that this is a personal account of how the science is getting done, and not a textbook. To which I would say: if you expect a personal account, then you won't be disappointed.

Overall, I would give it 4 out of 5 possible stars.

X marks the unakite

2010-02-12T07:15:00.001-05:00

Ahh, unakite, how do I love thee? Let me count the ways.

Nay, let me calculate the ways. ...That's why we have algebra. Let x = unakite.

Snowy Lily boots for scale.

Previous X marking the spot post. Previous unakite post. You may also want to check out the recent unakite posts on Looking For Detachment, About.com, and Ron Schott's Geology Home Companion Blog.

Anyone able to tell me where these two unakite "X"s may be found? First one to give the correct answer in the comments wins a "GEOLOGY ROCKS" bumper sticker!

My "Disaster?" post makes it to EARTH

2010-02-11T16:59:00.003-05:00

EARTH magazine just rebroadcast my "What makes a disaster?" post from a couple of days ago. Plus editor Meg Sever adds some thoughts of her own here.

Last chance!

2010-02-11T08:17:00.002-05:00

I'll shut the NOVA Geoblog survey down in a couple of hours. Last chance to express your opinion and give me a sense of who you are. Thanks in advance for taking three minutes to do that. For the 83 of you who have already completed the survey, my heartfelt thanks.

Out back

2010-02-10T11:16:00.001-05:00

Here's an iPhone shot of the view out the back of my house:

What makes a disaster?

2010-02-10T07:03:00.009-05:00

Dawn in DC: a blue grey hazy light filters down from the sky, just enough to illuminate the falling snow. I know that I'm not alone when it comes to being a bit tired of this snow. This is our sixth day in a row of being hemmed in. It's pretty profound, and the masses are starting to murmur with their frustration.

I'm astonished at how paralyzed the city is. It's really stunning. The federal government has been shut down every day this week, and according to the Office of Personal Management, it's costing $100 million a day in lost productivity. I was shocked to see that the Post Office didn't deliver mail at all on Saturday. What? The "Neither rain nor sleet nor snow nor dead of night..." crew called in frozen?

The snow has been falling all night, and not even once did I wake up to the sound of plows scraping their way down the street. I don't get it: where are the snowplows? Walking over to Woodley Park yesterday to ease the cabin fever, the weather was fine (as it was Sunday and Monday), and yet the streets were ankle-deep in grey slush. The sidewalks were usually in better condition than the streets: individuals' efforts to improve their small stretch of the common space were effective. But the city's response to the snow has been quite lackluster, from my perspective. I'd be more sympathetic if I saw them out there working, but I haven't observed a single snowplow plowing. (To be fair: I did see one snowplow, blade in the air, spreading salt. Also, I've been spending most of my time indoors, but I can see and hear the road.)

Salt supplies are running low, says the rumor mill. I believe it. Patience is running low, too. I'm at least thankful that here in the city, we haven't lost power, unlike many of my friends, colleagues, and students out in the suburbs.

Yesterday, when I was reflecting on people's thinking about the storm, I mentioned Haiti. I'd like to bring that up again today, and explore it from a different angle. The earthquake in Haiti was horrible and devastating, but it was (a) predicted, and (b) the equivalent of a large-magnitude earthquake that could occur elsewhere, like the Pacific Northwest or California. Yet it was really, really bad in Haiti, while the same magnitude quake, at the same depth, the same distance from San Francisco wouldn't be nearly as destructive. Why? Simple: the people of San Francisco are more prepared for earthquakes. A nation as rich as the United States, and a state as (formerly) wealthy as California, has the power to study earthquakes and their causes, to pass laws requiring buildings to be structurally capable of standing up to serious shaking, and the power to enforce those laws. Haiti's populaiton isn't so lucky: their unreinforced masonry buildings collapse readily when they get sheared; people die as a result.

Which brings me back to DC. While it's no Port-au-Prince, it's a big freaking mess that's not getting cleaned up anytime soon. This same snowstorm could hit Minnesota or South Dakota or Anchorage and I don't think anyone would really bat an eye. When I lived in Homer, Alaska, storms like this seemed to come around once a month or so. The difference was that people there had four-wheel-drive (and knew what that meant, unlike some of my SUV-driving neighbors inside the Beltway), studded tires, experience driving in snow, and a prepared attitude. The weather was the same; we just dealt with it better up there. Many private trucks had plows on front, and it was seen as a civic duty to plow out the road if you were the first one to drive down it after a storm*.

The culture of the DC area is as unprepared to deal with snow as Homer would be to deal with 100 degree F heat and 100% humidity. DC deals with mugginess like that every summer, though, so though it's a pain, it's not a catastrophe. Each area develops precautions and procedures based on the variations that nature typically throws its way. We make predictions based on the past. When something novel arrives, chaos breaks out, official services get disrupted, and it's up to the individual citizens to clean up the mess and look after one another.

Nature doesn't make disasters, in other words. We do.
____________________________________
* One time in Homer, I drove my pickup truck (which did not have a plow) down the road after about 2 feet of snow had fallen. I was the first one there, and I just charged on through. After I had gone about half a mile, my engine died. Surprised, I got out and shuffled forward to pop the hood. The entire engine block was surrounded by snow! As I was driving forward, there was nowhere for the snow to go except into the airy interstices under the hood. There was so much snow that the engine's air intake was blocked. I cleared it out (poking it with an ice axe I kept in the car) and started the engine up again, no problem. Then I drove on to work.

PS - Here's a gallery of images from the Washington Post.

Rorschach blot

2010-02-09T17:50:00.002-05:00

People see the most interesting things in the world around them. Some people see Stephen Hawking's initials in the universe's microwave background radiation. Others seek patterns in the clouds or lines on a palm. People are hard-wired to look for meaning in patterns. Not all patterns have meaning, but many do. Geologists, for instance, pay a lot of (legitimate) attention to patterns in ancient sediments: these patterns, called primary structures, give information about current flow direction, exposure to air, and the presence of living organisms. Others can orient us to which way was "up" when the sediments were deposited. Cross-bedding, mudcracks, and bioturbation are some examples of patterns with meaning. Seeing a dog's face in a rock exposure is an example of a pattern that lacks meaning, as surely as if one saw the same dog's face in the meaningless blobs of ink in a Rorschach test.

Lately, I've been thinking about the human predisposition for perceiving meaning in patterns.

The week before last, I gave a presentation at a local middle school about climate change. Before my talk, one of the teachers came up to me to ask if I thought that global warming could have triggered the earthquake. He whispered conspiratorially, "There have been a lot of earthquakes lately!" I said no, because (1) I couldn't think of a plausible mechanism for that to work in Haiti* and (2) there are perfectly good tectonic reasons for the Haiti earthquake, and (3) there haven't been more earthquakes lately than usual, at least not in any significant way.

As I type these words, the first snowflakes are falling in the second major snowstorm to hit Washington, DC, in less than a week. The first, dubbed Snowmageddon or the Snowpocalypse, dumped more than 18 inches of snow on the capital city. The city does not respond well to that amount of snow: schools shut, the government closed, and there were insane panicked runs on groceries at the area's stores. The new storm, dubbed Snoverkill, adds insult to injury with another 6 to 16 inches predicted. The schools I teach for, NOVA and GMU, have both been closed since last Friday. The way it's looking now, I'm not going to be working again until this coming Friday -- a full week lost due to the white stuff.

What's interesting to me is how people react to the snow. I mean this on two levels: one is the obvious fact that both the culture and infrastructure of Washington, DC, are quite poorly equipped to deal with a couple feet of snow. However, that's not as interesting as the way the snow serves as a reflection on people's mental states. Some people look at the two big snowstorms coming back to back and say, "Where's global warming now?" Others look at the same two storms, with fear that this is the new paradigm like The Day After Tomorrow, and say, "See what climate change hath wrought?" The thing is, they are both wrong.

Weather is not climate, even when two weather events occur in the same week. Tamino calculates that you need about 14 years of temperature data to tease out the long-term trend. Nine years isn't enough, and one week isn't enough. Yet people notice the "clumping" of these data: "two storms in one week! That's a pattern! It must therefore be significant! If it's significant, it's therefore reflective of a common cause, and that common cause is the one I have already decided to be true. Therefore these two storms are evidence of global warming / global cooling**" (depending on who you're listening to).

The thing is, data are clumpy. There is going to be noise in the data. When it comes to snowstorms, the noise is the weather. The noise is superimposed upon a longer-term trend. That trend is the climate. Likewise with earthquakes: no one expects earthquakes to occur with a periodicity regular enough to set to music. Earthquakes of a certain size have a certain probability of occuring in a given period of time, but there's no guarantee that one will occur. If you calculate the average number of earthquakes during a given period of time, and then compare any period of time to that average, your comparison time period will either have more earthquakes than the average or less earthquakes than the average. Ditto for snowstorms: some winters will be more snowy. Some winters will be less snowy.

There are exceptions, such as earthquakes triggered by other earthquakes, or a common cause. The recent earthquake storm at Yellowstone is sufficiently constrained in time and space to suggest that it indeed is a group related by a common cause (though it does not show a magmatic signature, another case of people seeing what they want in the data). Haiti's aftershocks play the same game, though not every earthquake that occurs in Haiti is necessarily connected to the big shock.

Anyhow, this stuff has been on my mind this week. The world is one big Rorschach blot, and humans see what they want in it. We are psychologically all too likely to jump from pattern recognition (noticing clumps in data) to conclusions (often pre-determined), without taking the time to really analyze whether there is in fact a trend present, and if that trend is significant, and if there is a logical causal mechanism to explain that trend.

We are a species that seeks meaning: some augur the future from tea leaves, while others engage in science and reason. Some methods of gaining access to meaning are themselves meaningful. Others are meaningless. Both surround us.

Stay warm out there.
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* Though potentially up in Greenland it could work due to glacial melting causing unloading on the crust, changing the stress field that's keeping a fault locked in place.
** It's probably also worth pointing out that snow does not equal temperature. It's precipitation. People are visually susceptible to the sight of snow: it registers more than numbers.

New geoblog: Bloc de Camp

2010-02-08T15:51:00.003-05:00

Just got a note about a two-year-old blog about geology that has so far escaped my attention (and possibly also the attention of the curator of the geoblogosphere, Robert Huber?) Bloc de camp (Catalan for "Field Notebook") is a blog dedicated to the geological heritage of Catalonia (country around Barcelona, northeastern Iberian Peninsula). It can be read in Catalan, Spanish and English. They are also on Facebook.

Upcoming changes

2010-02-08T08:46:00.003-05:00

Thanks to the 64 of you who have already completed the survey which accompanied the thousandth post here. The survey is intended for ALL readers of this blog, no matter who you are. So if you haven't yet shared your feedback, please do so now. I'll close the survey on Friday morning. I really am interested in your perspective. There are some major changes in the works for this blog, and I've already gotten some terrific ideas from the survey responses.

I'll announce the changes sometime next week... after I've heard from everyone who has something to say.

Snowtographs

2010-02-07T12:59:00.001-05:00

You may have heard that D.C. got some snow this weekend. (It's true.) We went for a walk this morning to check out what the snowed-in city looked like. Here are a few photos...

This is fun:

K Street, home of the lobbyists:

Group of robins hanging out at National Geographic HQ:

The White House gets whiter:

A magnolia tree in Jackson Square, not doing so well:

(Magnolias seem particularly susceptible to losing limbs via heavy snow...)

Photogenic trees:

Washington Monument:

Up-side-down Diplocraterion? Or just where someone sat in the snow?

This trace fossil is more obvious; Bicyclus, clearly:

The National Mall (Smithsonian's Natural History Museum at left, Capitol Building at right):

Doppelganger week for the Capitol:

Cold Triceratops:

Snow decorates the trees in front of the FBI building:

Pennsylvania Avenue:

Callan checks on the snow depth:

Guess this roof isn't very well insulated...

Some structures... Here's a set of two normal faults in a snow stratum atop a hedge:

(Glove for scale, of course.) Here's a different angle on these extensional structures:

(Because GMU classes were canceled on Friday, I assigned my structural geology students to make some structures in the snow -- like Kim's example, perhaps, or perhaps like this hedge, but really limited only by their own imaginations...)

Here's a different one:

That's a sheet of snow being driven downward by gravity, sliding over a roof (fault-like) but then arching up at the tip (this would look 'antiform' if it were rotated 90 degrees...). Kind of like a compressional antiform transitioning into a thrust fault, a common 'structural ingredient' in fold and thrust belts the world over.

Some more normal faults, including en echelon arrays like we saw last September in the volcanic tableland north of Bishop, California... These are viewed from the bottom -- they are forming in snow atop the glass roof of the pagoda-thingy that covers the Columbia Heights metro escalators. Notice too the color difference (due to more or less snow) from the peak of the pagoda (where the faults are -- an area of "crustal" thinning) to the bottom (where the snow is thickest).

Finally, if you haven't already seen it, check out this time-lapse image of the snow accumulating! And here's one from Greg Willis, who has shared videos on this blog before... Enjoy!

Stay warm out there, everyone...

Two books about evolution

2010-02-06T07:24:00.001-05:00

Book Month continues...

Why Evolution Is True - Jerry Coyne

I already mentioned one of the three great books about evolution that came out recently: Your Inner Fish, by Neil Shubin*. I heartily recommend pairing Fish with WEIT, as they have some overlap in content and style. This is an easily-accessible review of the most important (and compelling) bits that pile up in support of the idea that evolution has occurred over time, and that natural selection is its principle driver. It's full of interesting facts that are clear refutations of the idea of divine creation of all species from separate starting points in the recent geological past. FYI, Coyne is also a blogger: he writes semi-daily at the blog Why Evolution Is True (shocking title, eh?).

The Greatest Show on Earth - Richard Dawkins

Richard Dawkins gets plenty of press time for his athiest viewpoint, and he's written a book about that, too (which I haven't read). As a result, many theists probably won't want to touch any of his other tomes with a ten-foot pole. But I assure you, that would be a huge mistake when it comes to The Greatest Show on Earth: this is an amazing, rich, awesome book. It demolishes the notion of a young Earth and special creation with a treasure trove of information about biological systems. More importantly, it celebrates the beauty of evolution: Dawkin's delight in the various evolved solutions to the problems of living is evident. Like luciferin, it shines from the page. The way I see it, Why Evolution Is True and Your Inner Fish play the part of "executive summaries," while The Greatest Show on Earth is the juicy, complicated, tangled jungle of evolutionary explanation. It's great. While it lacks the quality of being concise, Dawkins' erudition and clear-mindedness more than make up for it. Consider Coyne's WEIT as your appetizer, but save Dawkins for the main course.
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* By the way, Neil Shubin has posted PowerPoint slideshows of the images in each chapter of Your Inner Fish for use by educators teaching about evolution. Check them out. Unfortunately, there are a substantial number of spelling errors in the captions to these images, but the images themselves could be quite useful to anyone wanting to incorporate an 'evo-devo' element into Historical Geology or Paleontology.

"Reading the Rocks" by Marcia Bjornerud

2010-02-05T07:33:00.002-05:00

Book Month continues...

I recently read the excellent book Reading the Rocks, by Marcia Bjornerud. I would recommend this book to anyone interested in their planet. I think it's an equally good choice for professionals and interested amateurs. The book works on several levels. It's lyrically written, with an economy of flourishes, but an ear for a good turn of phrase. She's also really keen on analogies, and that makes me like her a lot. Finally, she seems to be a kindred spirit, using geological insight as a gateway to philosophical perspective. The book is rich in detail, though broad enough in scope that it will satisfy a structural geologist, an astronomer, or your average run-of-the-mill nature lover.

A taste of her style:

"Human consciousness is arguably the first truly novel innovation to arise since Cambrian time, in the sense that the technologies our consciousness has spawned have freed us from the limits of our own body architecture." (p. 172)

"Over more than 4 billion years, in beach sand, volcanic glass, granites, and garnet schists, the planet has unintentionally kept a rich and idiosyncratic journal of its past.... The genre varies from breathless thriller to quotidian diary; the action ranges from microbial metabolisms to mountain building." (p. 5)

Under a section subtitled "Grammar and Syntax of the Three Rock Languages," Bjornerud says, "Just as you wouldn't look to a cookbook for information on military history, you wouldn't expect a sandstone to tell you much about the Earth's interior. Sedimentary rocks are the best reference works to consult if you are interested in past conditions at the surface of the Earth - for example, ancient climates, biological activity, or the distribution of water bodies. Igneous rocks chronicle the long-term chemical evolution of the Earth and provide glimpses into processes that occur at inaccessible depths. Metamorphic rocks, born in one setting (sedimentary or igneous) and transformed as they encounter new environments, are the travel writers of the rock world, chronicling their astounding journeys through the crust." (p. 33)

I love how she gives anthropomorphic personalities to rocks. This is her great talent as a writer. Along similar lines as the quote above, she later compares mafic to felsic igneous rocks: "A mafic rock like basalt generally has tales to tell of life in the mantle, while for a felsic rock like granite, whose progenitors were themselves crustal, the mantle is a nearly forgotten ancestral homeland." (p. 43)

She has a great analogy for radioactive decay, using "parent" and "daughter" as part of the analogy itself: A "magnanimous parent who transfers half of his savings to his daughter each year on her birthday." Each year, the parent has less money, but the daughter's wealth has grown by exactly that same amount. "At any time, an external auditor could determine the age of the girl - the number of years the parent had been giving money to her - by finding the ratio of the amount in the daughter's account to the amount in the father's account." (p. 58) Clever!

She gives some great comparisons for viscosity, including glacial ice, basaltic lava, rhyolitic lava, motor oil, water at room temperature, and blood (which she helpfully reminds us is thicker than water).

Chapter 3 concludes with a great comparison between the small and the large: "...Small phenomena can wield surprising power: A trivial deviation from sphericity causes the entire planet to wobble, raindrops and tiny flaws in minerals bring down mountains, trace gases in the air govern climate, and microbes modulate the atmosphere. Perhaps the greatest challenge we face in attempting to fathom the Earth is to gain a proper sense of our own size as a human species; like spoiled children, we routinely overstimate our importance on the planet but underestimate the destructiveness of our self-absorption." (p.98)

Criticism:

The "currently accepted geologic timescale" at the beginning of the book includes "Tertiary," with no mention of Paleogene or Neogene. Frowny face.

She attributes John Playfair's quote about being "giddy from peering into the abyss of time" directly to James Hutton. Tragically, Hutton was never so eloquent himself.

Overall: Highly recommended. Get it; read it.

Icy volcanic breccia

2010-02-04T16:56:00.008-05:00

This is beautiful: That's an image by Chris Waythomas of the USGS, hosted by the Alaska Volcano Observatory website. It shows a cutbank (river-eroded alluvium deposit) along Rust Slough, south of the Drift River Oil Terminal, northeast of Redoubt Volcano. The sediments exposed were deposited on March 22, 2009 by a lahar (volcanic mudflow). The lahar deposit is 2.5 m thick. When I saw this image tonight (as I was searching for another shot), I was particularly struck by the subrounded clasts of ice in the mud. Here is ice acting the part that chunks of rock usually play. Technically, ice is a mineral, and so these chunks are sedimentary clasts much like any other... But to me there's something distinctly different about seeing ice cobbles and pebbles included in a sedimentary deposit. On a planet as warm as Earth, this sort of thing isn't likely to be preserved in the geologic record. It would melt! ...And that gets me thinking about other planets and planet-like objects, like Titan. The Huygens probe took pictures of sedimentary clasts, presumably of ice, on the surface of that moon. Other cold locations could have CO2 ice ("dry ice"): That makes for the sort of rock specimen that would be really difficult to keep on your shelf as a 'deskcrop'...

An additional thought: how could the former presence of icy clasts have influenced the geologic record? Perhaps ice clasts were an integral part of a deposit as it was laid down... but then later the ice melts away. How could we detect and control for this?

Sierra Nevada geologic map repository

2010-02-04T06:32:00.002-05:00

Wow. Here's a great resource for those who do research in the Sierras, or the geologically-inclined visitor. Making this available online is a terrific public service by Allen Glazner and Mike Oksin at UNC-Chapel Hill.

Via Geology News' automated reposting of "geology" items from del.icio.us.

Congratulations to Michael Welland!

2010-02-03T08:19:00.003-05:00

The word is out: Michael Welland, author of Sand: the Never-ending Story and Monday's guest blogger here, is being honored. Sand has been awarded the 2009 John Burroughs Medal, which puts Michael in extremely esteemed company: John McPhee, Gary Paul Nabhan, William Beebe, Edwin Way Teale, Aldo Leopold, Roger Tory Peterson, Barry Lopez, and David Quammen are among the luminaries who have earned this award. Well done, Michael! You make us proud.

I can't wait to see what this guy writes next...

"Cataclysm" by Doug Huigen

2010-02-03T07:44:00.003-05:00

I mentioned in Monday's Sand post that this was "book month" here at NOVA Geoblog. That means it's now time for a quick book review of CATACLYSM: When Human Stories Meet Earth's Faults, by Douglas W. Huigen...

When I was writing my Benchmarks piece for EARTH magazine about the Hebgen Lake earthquake and the Madison River landslide, I spoke on the phone to Doug Huigen, who was then just finishing a multiyear project learning about the geology of the Hebgen Lake area, and interviewing survivors of the event. He was very genial and shared some great information when we spoke.

Later in the year, my summer Rockies field course brought me out to the site of the landslide itself. Here's me and my students at the Earthquake Lake Visitors' Center, talking about the structure of the mountain behind us, and why it failed almost fifty years previously:

After I was done pontificating, we went inside and watched the compelling movie they show there, and then I noticed that Doug's book was for sale on the counter. I bought a copy.

Months later, I finally found the time to read it. For some reason, though, I've found it difficult to finish up with my "book review" blog posts. I started this one in late October, for instance. I'm hoping that by declaring February to be "book month," I can motivate myself to crank through these reviews.

Cataclysm is a nice introduction to the events of August 1959, viewed both through the people on the ground experiencing the earthquake and landslide, and through the perspective of modern-day geological insight. Huigen spoke to a great many survivors of the event, and relates their stories with compassion and an ear for colloquial language. The book is subdivided into three main sections: (1) stories of people during the event, (2) a bunch of photographs and graphics showing the area, the people, and the geology, and (3) a description of the geology underlying the earthquake and landslide. The story is very compelling, and I think it's worth reading this book if you're going to be visiting the Hebgen Lake landslide site.

The book is self-published by Huigen, so there's some issues with typos and formatting of photo annotations, but I guess that could also be seen as part of its charm. It's an excellent repository of a lot of information, and I learned some new things by reading it. I was particularly pleased with the image Huigen has on the inside of the front cover: a sketch of the major geological features in the area. The inside of the back cover is a gorgeous geologic map of the same terrain, but Huigen didn't include the map's explanation, so you have no idea what the various rock units actually are (unless you're already familiar with the area).

Bottom line: not the most amazing piece of literature in the universe, but an important compilation of data about the Hebgen Lake earthquake and landslide: data both of the geologic variety and the 'oral history' variety. I'm glad I read it.

Upcoming changes to NOVA Geoblog

2010-02-02T14:33:00.001-05:00

I got a note from Blogger today:

Last May, we discussed a number of challenges facing[1] Blogger users who relied on FTP to publish their blogs. FTP remains a significant drain on our ability to improve Blogger: only .5% of active blogs are published via FTP — yet the percentage of our engineering resources devoted to supporting FTP vastly exceeds that. On top of this, critical infrastructure that our FTP support relies on at Google will soon become unavailable, which would require that we completely rewrite the code that handles our FTP processing.Three years ago we launched Custom Domains[2] to give users the simplicity of Blogger, the scalability of Google hosting, and the flexibility of hosting your blog at your own URL. Last year's post discussed the advantages of custom domains over FTP[3] and addressed a number of reasons users have continued to use FTP publishing. (If you're interested in reading more about Custom Domains, our Help Center has a good overview[4] of how to use them on your blog.) In evaluating the investment needed to continue supporting FTP, we have decided that we could not justify diverting further engineering resources away from building new features for all users.For that reason, we are announcing today that we will no longer support FTP publishing in Blogger after March 26, 2010. We realize that this will not necessarily be welcome news for some users, and we are committed to making the transition as seamless as possible. To that end:
We are building a migration tool that will walk users through a migration from their current URL to a Blogger-managed URL (either a Custom Domain or a Blogspot URL) that will be available to all users the week of February 22. This tool will handle redirecting traffic from the old URL to the new URL, and will handle the vast majority of situations.
We will be providing a dedicated blog[5] and help documentation
Blogger team members will also be available to answer questions on the forum, comments on the blog, and in a few scheduled conference calls once the tool is released.
We have a number of big releases planned in 2010. While we recognize that this decision will frustrate some users, we look forward to showing you the many great things on the way. Thanks for using Blogger.

Your Sand questions answered

2010-02-01T07:33:00.044-05:00

Today we have a special post here at NOVA Geoblog. Author Michael Welland joins us to answer a bevy of questions about the topic of his expertise: sand. Michael's book Sand: The Never-Ending Story is now out in paperback, and this post is one stop on his "virtual book tour" through the geoblogosphere. I really enjoyed reading Sand, and I reviewed it last year in EARTH magazine (hardcopy only, I'm afraid: no link possible). I was tickled to see that a quote was mined from my EARTH review for the back cover of the paperback edition of the book, a first for me.

If you have a sand question to ask, leave it in the comments, and Michael can respond there, too.

This post also serves to kick off "Book Month" here at NOVA Geoblog. All this month, I'll be blogging about the books that I have read recently.

All questions in this post come from my spring 2010 Physical Geology students. Enjoy! -CB

What are people who collect sand as a hobby called?

"Odd!" ...They are also often called arenophiles, "sand lovers" but strictly, that's a mixture of Latin and Greek - "arena" is the Latin for sand. To be consistently Greek, they should be "psammophiles" but then that term tends to be used by biologists and botanists to describe critters and plants that live in the sand.

How come sand gets everywhere when you go to the beach? And by everywhere, I mean everywhere...sealed Ziploc bags, inside cell phones, places you don't want it...everywhere. Or, on a more scientific sounding note-beaches that are eroding. Is it due to sand being swept out by the ocean waves faster than it can be replaced? (How is sand formed?) If that's the case-why do some beaches erode faster than other? Is it because of the width between the dunes(?) and the ocean?

Boy, do I know about sand getting everywhere! After my Sahara travels, my backpack pockets still contain sand, my camera zoom makes uncomfortable grating noises, and I had a hell of a time explaining to my cellphone company why there were sand grains under the keys (I'd stupidly used its calculator for map scale conversions when we were trying to figure out where we were). I guess this problem is just another of the strange behaviors of granular materials in that size range.

Now, as for beaches, they are just about the most dynamic environments on earth, changing every day, with the seasons, with every storm, and with changing sea levels. Check out the story of the wholesale move of the Cape Hatteras Lighthouse. Every beach has a sediment budget - incomings and outgoings that constantly change. Sand is added to the beach (but also carried away) by longshore drift and by the action of every wave. A storm will erode unimaginable amounts of sand - which is then deposited elsewhere. Sand blows off the beach and onto the dunes, or off the dunes and onto the beach - an incredibly complex system. Typically, at certain points along a coast sand will be swept into the head of a submarine canyon and flushed out into the deep sea - essentially never to return (check out, for example, the Monterey Submarine Canyon).

Here are a couple of interesting photos of where sand ended up after Hurricane Katrina:

And here are three photos of Dauphin Island, Alabama, before Hurricane Ivan, after it, and after Hurricane Katrina - spot the differences!

Over the course of several thousand years, can a black sandy beach turn into a white sandy beach? I have heard about green sand. Is green sand existent and where can you find it? What elements is sand made out of ? ...And why does its color change in other places?

In talking about the definition of sand in terms of size rather than composition, and the different types of sand, I've begun to answer these questions. Just as the cuisine of a local restaurant is dominated by local ingredients, so is the composition of a sand in any one place. You wouldn't expect to find beaches of coral fragments in Greenland, or sand grains of old metamorphic rocks in Hawaii. The sands of a particular beach may have been carried a long distance by rivers and coastal currents, but they originate from the same system, a system that is stable over long periods of time. The river and beach sands of the east coast of the US tell the story of the erosion of the Appalachians and the effects of the Ice Ages. So no, a black sandy beach will not turn into a white sandy beach over the course of a few thousand years - but if, over the course of a longer period of time, different source rocks are exposed in the areas where the sand grains originate, or if there is a major reorganization of sand-transporting currents, then the beach composition will change to reflect that. We see this all the time in the geological record - changes in sand composition that tell us about changes in provenance, tectonic activity and so on.

But then, as I was writing this, I suddenly remembered an example of a black beach turning into a normal beach - overnight! If you go to any beach and look at the ripples in the sand, there will generally be smears of dark-colored grains emphasizing the forms of the ripples. These are grains of heavier minerals, often iron oxides, which are winnowed by the action of waves because of their weight. If this winnowing, by waves, currents, or rivers, takes place over a long period of time, then considerable concentrations of heavy minerals can result; these deposits, called placers, can be commercially important and are the sources of diamonds, gold and many other important mineral commodities. But on a beach, just as easily as such a deposit can form, so can it be removed by a storm; I described an example of this in the book:

...such an occurrence was the cause of one of Thomas Edison's many business failures. On a fishing trip with friends off the coast of Long Island, Edison put into shore for lunch and found the beach covered with a layer of black sand. He took some home and discovered that the black grains were a magnetic iron oxide mineral - magnetite - which stuck to a magnet while the common sand grains fell off. Edison's enthusiasm ran, as it often did, ahead of his business sense, and he immediately arranged for the purchase of the beach and the manufacture of separating machinery. Unfortunately, by the time he and his colleagues returned to Long Island, a winter storm had reworked the beach and completely removed the black sand.

So there's a case of a black sand beach disappearing!

Green sand - yes, it exists, most famously on Hawaii. Local ingredients again, the volcanic rocks contain crystals of the apple-green mineral olivine, and this can become concentrated on some beaches to become the main constituent of the sand - placers again. Here's an example from the Big Island:

Sand comes from sediments that are carried down from rivers that come from mountains. So is sand a mixture of minerals and dirt? ...Or just a lot of different broken down minerals? I just watched something about China's issue with being continuously battered by massive sandstorms. What I want to know is: Where is the sand coming from? Why is it hitting China, and what are the health risks/other consequences of these sandstorms?

The breakdown of rocks by chemical and physical weathering and the transport of the debris by rivers is the most common origin of sand - but it's not the only one. Beaches in the tropics are made of sand that is biological in origin - shell fragments, bits of coral, and the shells of minute organisms. Which brings us to a key point: Sand is defined purely by size.

This is for a very good reason - granular materials that fall in this size range behave very differently from things smaller and things bigger. And those behaviours are often bizarre. It really doesn't matter what the sand is made of, its composition. And note that, reflecting the fact that nature works in multiples, each category is twice the size range of the next smaller one. So, it doesn't matter if the material is made up of 1 mm quartz grains, shells, diamonds - or sugar - technically it's coarse sand. It can be made up purely of quartz or purely of foraminifera shells, or a mixture of minerals and rock fragments, or a mixture of coral and shell fragments - it's all sand. Some beaches in the tropics are made up almost entirely of sand-sized pellets of dried fish shit.
Dirt is the non-technical (and mostly American) term for soil, and soil is the in situ material that results from the conspiracy of chemical and physical weathering and organic material and activity. Once it's eroded and transported by wind or water, it isn't dirt any more. So, technically, the dirt in much of Nebraska is sand (the Sand Hills support only very poor vegetation); once the dunes become active again (perhaps as a result of changing climate) that sand will be on the move once more.
And that's a big part of what's happening in China. More than 2.5 million square kilometres (a million square miles - more than four times the area of Texas) of the country is desert, and so sand and dust storms have always been a problem. But poor land management on a massive scale - removal of forests, over-grazing, and soil-depleting agriculture - has made the problem worse. What had been stable soil, dirt, is now exposed to the winds and on the move - very much like the dustbowl conditions of the American Midwest in the 1930s. The total area of China's deserts is growing at around 200 square kilometers (80 sq mi) every month, and every year tens of thousands of tons of sand and dust are blown into Beijing. China's capital has always suffered from dust storms, helped again by the ice age, when grinding glaciers wore rocks down to flour, technically known as loess, which, once airborne, blankets huge areas for long periods of time. But Beijing's dust storms are turning into sandstorms. It's not necessary to travel to the Gobi Desert to find encroaching sand; it's a mere hour's drive out of Beijing. The Great Wall, built to defend against invaders from the west, is proving no match for the onslaught of sand: whole sections are being destroyed by the storms.

So the sand is coming from the interior deserts, but more and more from degraded landscapes that are newly becoming desert. The problems for homes and infrastructure are enormous, but so are the health risks in populated areas from particulates - hence the dramatic measures taken at the time of the Beijing Olympics.

How come there is so much sand on the shores and coastlines of the earth, and absolutely none as you move toward the middle of a country or continent?

Don't tell the residents of Nebraska that - a quarter of their state is covered in sand dunes! The Sand Hills are the largest area of dunes in the western hemisphere, covering 60,000 square kilometres and were active and mobile between 1000 and 1200 CE. They were formed originally from the debris of the glacial erosion of the Rocky Mountains. The hills were stabilized eight hundred years ago but have had episodes of reincarnation since: a long drought toward the end of the eighteenth century resuscitated dunes on the Great Plains, whose activity caused problems for the westbound wagon trains decades later.

You can find more imagery and information here. And think about the great active deserts of the world where huge amounts of sand are to be found - the Sahara, the Arabian Peninsula, essentially the entire interior of Australia, a quarter of the land area of China. But it's not just the deserts - every river bank and lake shore has sand. About the only places on the earth's surface where sand is rare are the very deep ocean floors - and it's rare but not absent. Sand can be dropped from melting icebergs and flushed out into the deep oceans by the tremendous energy of turbidity currents, slurries of water and sediment hurtling down the continental slopes and spreading out across the deep ocean floors; any of the great deep ocean currents can move sand around - and they do. And there are countless sand grains in your back yard, mixed up in the soil.

Here's a Google Earth image of Nebraska:

Hoping this question related enough to sand, because I'm still under the impression that all/most glass is made of sand. I've heard that in stained glass windows inside ancient churches, there is a "bulge" at the bottom of the glass, and that because of its disorderly atomic structure, gravity can "pull" it down a bit after hundreds of years. I've also heard that this is totally wrong, and that the bulge is just an effect of the way they made stained glass at the time. I'd love it if your friend could shed some light on the issue.

It's an old and common "urban myth." Although glass does flow, the timescale over which it happens is far too long for even the oldest windows to show any effect. Old methods of making glass did not create perfect sheets and, logically, if a piece is thicker at one end than the other, you would install the thick end at the base of the window. There's a good article about the myth on Corning's website.

What makes quicksand so powerful that it can drag a human down?

Another "urban myth!" There's a great episode of Mythbusters that examines "killer quicksand" and has them bobbing around in a giant tub of quicksand, trying to be sucked in. They bust the myth: "Quicksand is denser than water; the greater the density, the greater the buoyancy of objects within. Any victims found in quicksand likely died for some other reason (i.e. exposure to the elements)." You can watch the episode here.
Quicksand is an example of one of the strange behaviours of sand-sized granular materials - dilatancy. Here's a bit about this from the book:
Quicksand forms when there is sufficient water in between the grains to separate them - to push them apart through dilatancy - but the water is prevented from draining; the sand is in suspension. This can happen when an incoming tide scours large holes in the sand that are rapidly filled by the outgoing tide, trapping water and air in the sand. Or a subsurface spring or other source of water percolates upward through a body of sand, dilating it. The result is a slurry, delicately balanced between solid and liquid, switching instantly but briefly between the two states with the slightest disturbance. But being a mix of water and sand, quicksand is more dense than water, and the human body floats well in it. The problem arises when a person floating in quicksand tries to move too quickly; the movement destroys the dilatancy of the slurry and the grains reconvene and jam back into a solid, effectively cementing the unfortunate person in place. It has been estimated that the force needed to pull your foot out of jammed quicksand is about that needed to lift a medium-sized car. The key is to wiggle, allowing water to fill the space created around you, and then swim, very slowly. Quicksand is lethal because lone individuals die of exposure, starve, or drown when the tide comes in, not because they are sucked under.

What is the calculated estimate of the amount of sand on Earth?

Essentially impossible to calculate - particularly if you include all the sand grains in ancient sandstones. But that hasn't stopped people having a stab at it. I wrote a bit about this in the book:
In 1980, Carl Sagan, the enthusiastic popularizer of all things astronomical, kicked off one of the most enduring, entertaining, but quantitatively pointless debates about large numbers. He declared, in his television series Cosmos, that "the total number of stars in the universe is larger than all the grains of sand on all the beaches of the planet Earth." The calculations are ongoing and the debate rumbles on, particularly in the ethereal realms of the internet, and there are, predictably, two schools of thought. While estimates are always increasing, the number of stars is the easier number to calculate: anywhere between 1020 and 1022. As for the grains of sand - well, it depends. What are the assumptions in terms of grain size and, indeed, what counts as a beach? Only the areas of sand above high tide, or areas underwater as well? Depending on how you choose to do the calculation, you can derive a number that is larger or smaller than 1022. And if all the sand grains of the Earth are included, not just those on beaches, then it's again a different matter.

Is sand from different places unique enough for someone to determine where it came from?

Absolutely - to the extent that sand stuck under a vehicle or in the sole of a shoe can and is used in criminal forensics. Simplest if I quote the section on this from the book:
With the sophisticated microscopic diagnostics now possible, the character of soil and sand as evidence in a wide variety of criminal cases has taken on increasing significance. There are crimes that rarely make the headlines, such as cactus smuggling, that can be routinely solved by being able to point to the origin of sand clinging to the roots of the contraband. Investment scams where evidence for a new gold prospect is "salted" with grains of gold from elsewhere can be uncovered by a microscopic look at those grains.
A significant amount of the world's gold supplies comes from the sands of ancient and modern rivers. In 1997 a shipment of these grains of gold worth $3 million was made from mines in the interior of Ghana to the coast and then on to London for processing. After a dispute over the arrangements and cost, the shipment was moved on to Canada via Amsterdam. Canada was the first place where the crates were tagged and given new seals. When they were eventually opened, they contained ordinary sand and iron bars. Where on the shipment's circuitous route had the substitution taken place? The sand was examined by Richard Munroe, a Canadian forensic geologist and policeman. If the substitution had been made in London or Amsterdam, the sand would likely bear the imprint of its northern European origins - particularly the action of ice from the glaciers that had so recently sculpted the continent. But none of those signs were there. Instead, the grains bore the distinctive features of being subjected to a tropical climate, and their composition was typical of the geology of the interior of Ghana. While local security difficulties prohibited making an exact match of the sand grains, any Canadian involvement was ruled out and the insurance claim filed by the mining company was dropped. Sand is a popular material in crimes of "substitution"; in the lively commerce between North and South America, sand has been substituted for, among other goods, cigarettes going south and perfume going north. The genetic fingerprint of the sand involved has pinpointed the location of the crime and helped prove innocence and guilt.
Sand and soil found in the soles of shoes, on clothing, or on tires can place people or vehicles in a particular place - however much they may deny it. Geology has become a standard tool in the kit of government forensic laboratories the world over, but it has been around for some time. The fictional Sherlock Holmes claimed to be able to describe an itinerary from mud splashes on trousers. In real life, evidence from sand has been used for over a hundred years. In 1908, in Bavaria, a poacher was suspected of murdering a young woman. His wife had cleaned his shoes the day before the murder, but they now had three layers of sand and soil stuck on their soles. As part of the investigation, one Georg Popp, a local chemist, applied his geological expertise to these layers. He reasoned that the layer next to the sole of the shoe was the oldest; it was made of the same materials as those outside the suspect's house. The second layer contained red sand and other materials identical to those from where the body had been found. The last and most recent layer contained brick fragments, cement, and coal dust that matched samples from where the suspect's gun had been found. What this layer did not match was the soil from the fields where the suspect claimed to have been walking at the time of the murder. The prosecution case was complete.
On a dark, rainy night in September 2002, a black truck parked beside the Shenandoah River in Virginia. Another truck pulled up, and the window rolled down to reveal the barrel of a shotgun. The driver of the first truck was killed at point-blank range. The murderer left in a hurry, the wheels of his truck spinning in the sand and gravel. After a preliminary investigation, the police had a suspect but insufficient evidence to prove guilt. When the suspect was seen starting to wash his red pickup truck, the police swooped. The truck was spattered with fresh mud: time to bring in the forensic geologists. The mud contained some very distinctive sand grains, a variety of minerals that could only have come from a local quarry. While the quarry was not where the murder had taken place, water washed debris from the quarry into the river, which carried it downstream, mixing and diluting it with the other sand and mud in the river. At low water levels, these were dumped in sandbanks along the river's edge. Geological sleuthing demonstrated that each successive sandbar downstream from the quarry contained less and less quarry debris, and the only one that precisely matched the material from the suspect's pickup was the scene of the murder. The suspect pled guilty in the face of this incontrovertible evidence.
Forensic geology has played a part in a wide range of criminal cases worldwide, but perhaps the most high-profile, yet disappointing, example was the murder of the Italian prime minister Aldo Moro. In May 1978, the body of the kidnapped prime minister was found in a car in Rome. Sand from his clothes and shoes, and from the car, was shown to have come from a particular stretch of beach near the city, yet searches of the area provided no evidence. Other forensic work confirmed the association with this beach, yet the connection with the suspects could not be proved. Years later, the kidnappers declared that they had planted the beach sand as a decoy - whether this is true or not remains unclear.
The world's first database of sand grains has been assembled from soils in the United Kingdom, specifically for police forensics. This database contributed key evidence for one of the country's particularly appalling recent criminal cases, the murder of two young Cambridgeshire schoolgirls in 2002. Once again, distinctive soil under the murderer's car tied him to the location where the victims had been
buried.

I know we use sand for glass (and in turn all products that use glass), however, are there any odd or interesting uses for sand that people don't usually know about? Are there any surprising or "out there" uses for sand?

Well, how about computer chips? And all the important minerals (as well as gold, diamonds, sapphires, rubies and garnets) that are found as placer deposits? These include titanium, tungsten, tin, platinum, and niobium. Sand is used as a filter, as a casting method in foundries, in different specialist sports surfaces. Silica and silicon products are used in pharmaceuticals, cosmetics, paper, and paint. Oh, and don't forget concrete.

Is sand a good medium for fossilization to occur in, and if so what signatures would a fossil show in relation to being formed in sandy soil?

Sand is not a great "fossilizer" compared to mud, for example, simply because sand is deposited in very dynamic and high energy environments - beaches, rivers and so on - and is constantly being re-transported by currents and moved on. Organic remains are easily damaged and broken up. That said, a lot of fossils are found in sandstones and trace fossils, footprints, tracks, trails and burrows can be quite common.

Because of the large size of rocks, it can be easy to use distinguishable features to date and classify them by. Can sand grains be dated in the same fashion as a large slab of granite, or do they need a more precise way to measure how old they are?

Dating a rock like granite involves finding the age of cooling and crystallisation of individual minerals through the radioactive isotopes or fission tracks they contain. Some minerals are better for this than others - quartz doesn't contain much in the way of radioactive components, so isn't much help for this. But some minerals that end up as sand grains are - zircon grains are the classics. They are tough as old boots and preserve a very good record of their cooling history. The oldest earthly possessions that we have are zircon sand grains from sandstones in Australia - they're up to 4.2 billion years old. But that's the age of the mineral grains, not the sandstone that now contains them.
One thing we can do with quartz grains is measure how long they have been exposed to cosmic radiation - e.g., how long a sand grain has sat on the surface of a place like the Atacama Desert. There are various different methods all of which are referred to as luminescence dating. It takes an awful lot of work but the results can be amazing - the Atacama has been a desert for far longer than we thought, for example. The USGS has a very good section on the different methods. It's a powerful method for unravelling the history of a landscape and for archaeological research. One example that I particularly like relates to prehistoric rock paintings in Australia. There are no materials that allow dating of the paintings, so their age is often a mystery. However, there are places where now-vanished wasps built their nests over part of a painting, using sand grains in the process. Those sand grains can be dated using luminescence methods and thus give a minimum age for the rock art. I came across exactly the same thing in the Sahara:

I remember sculptures of sand being struck by lightning can occur on beaches at times. My question focuses on how lightning makes sand form into random shapes of "glass" like structures? And when lightning does strike sand, does it have to be a certain type of sand?

It really is glass - the instantaneous and intense heat from the lightning fuses the sand grains into a solid structure, often a tube, and the result is called a fulgurite (from the Latin for lightning). This can happen in essentially any kind of sand and they can be really big - the record is one 17 feet long. They can also be found in ancient sandstones - lightning strikes from a couple of hundred million years ago. Silica glass was also formed by the energy of the first nuclear test explosion at White Sands in 1945 - the sandy soil was fused into glass by the heat. Fulgurites come in all shapes and sizes - the one here is fairly typical:

CB again: Have any additional sand questions for Michael? Leave them in the comments! If you found this blog post interesting, I recommend Michael's book. I have a copy I can loan to NOVA students, or better yet, you can buy your own!

1K

2010-01-29T07:43:00.003-05:00

This is the 1000^th post on NOVA Geoblog.

I passed up the opportunity to engage in anniversarial navel-gazing this past December with the blog's second birthday, opting instead to dish out some recognition to other corners of the geoblogosphere. A thousand posts, being an arbitrary but satisfyingly round number, encourages me to think about what I'm doing with this blog, and where it's going. Today, if you'll indulge me; I offer a few reflections (#1-4) and a request for feedback from you (#2, #5).

1) I've been gratified with all the positive feedback I've gotten (via comments, via e-mail, and in person), mystified at the persistence of some readers in posting argumentative comments, disappointed overall at the lack of commenting, and annoyed at the increasing number of spam comments, which I delete as soon as they come in (a chore). Thanks to everyone who considers this site worth taking the time to read.

2) I'm curious who's reading. I get data that suggests a lot of people are stopping in, but not a lot of people leave comments. If you're a regular, but you don't leave comments, let me extend an invitation to you to say "hi." You can do this via the comments section below, or shoot me an e-mail if you don't want to be all public about it.

3) I enjoy blogging, but I'm also a bit compulsive about it. This blog has existed for 770 days, and the 1000 entries I've posted over that time works out to an average of ~1.3 per day. I'd like to tone that down a bit. In the future, I'm going to give myself permission not to post something every single day. Brace yourselves: I'm going to start applying the brakes.

4) This summer I hope to launch a new geology vodcast series. This has been in the works for some time, and I'm excited that it is finally moving forward. I'm looking for suggestions for a clever title for the series (feel free to leave a comment below if you have a good idea what to call it). It will be available via iTunes and a dedicated YouTube channel. I will also embed the YouTube videos in blog posts here.

5) Lastly, to better determine the future of this blog, I have put together a 5-question survey that I would like to ask you to complete. It is totally anonymous, and will take only 3 minutes of your time. I will leave this survey open for the next 2 weeks, but I ask you to please take the time now to click the link above and complete it. This is for everyone who is reading these words: it's not just for hard-core geologists or for other bloggers. It's for all readers. Thank you!