Looking For Detachment

For my small part this year, I noticed a map at ESW that shows links to a Google Maps map showing earth science organizations for each state. The one for Nevada, for example, can be seen here.

I went a little bit farther and added each organization and location on the map (generated originally by user ESW, Earth Science Week) to a map of my own, to which I added a few other organizations. That map is embedded below.


I was working on this post last week, when at some point my computer or browser or both went into overload or freezing mode, and I had to reboot, somehow losing the draft of the post in the process. I had added only a few Nevada geological organizations to my embedded map; all the ones I added consist entirely of statewide and chapter meeting places of the Geological Society of Nevada.

The GSN website has a large number of geological links — to state, U.S., Canadian, and other foreign geological surveys, to various professional organizations, and to various State of Nevada departments and divisions. You will also find many other geological links, including several for the USGS. I had started to add the location of the USGS Nevada district office to my map, when I realized my small but increasingly time consuming project had been put in jeopardy by the U.S. government #shutdown. I couldn't find out where the district office in Nevada is located! (The district office referred to may be the USGS Nevada Water Science Center office in Carson City rather than a geologic field office, not sure.) Instead of the website linked to at this URL, I got the main USGS page and the following announcement:

Current USGS main page, retrieved 14Oct2013.

In any case, check out the other geological links at the GSN. And check out their interactive map showing locations in Nevada where their publications (mostly field trip guides from the many GSN symposia and biannual to yearly field trips.

As part of Earth Science Week, today is Geologic Map Day!

Long before I became a geologist, I had already developed a love of maps, a love dating back to a cross-country trip I took with my family when I was five. Besides the road maps we traveled with, I had a large wall map of the U.S., on which I kept track of the states I had visited and the roads that had taken me there—these were the major highways of the day, like U.S. Highway 40, now replaced by I-80 in most places. As time went on, I learned more about other types of maps, in part thanks to National Geographic, and eventually, maybe in high school, learned how to read topographic maps and came to know the basics of reading a geologic map.

I got my first real taste of geologic mapping at field camp. I found it fairly challenging: I was still getting up to speed on the tools in use—simple tools like a quadrant-based Brunton compass—and I was also becoming gradually familiar with following contacts up and down and around hills, and across broad and hot expanses, mostly of desert.

Geologic mapping really became fun for me on our second mapping project during the summer of 1978 (several early stories are listed here), when I found that I could do it well and that a good geologic map tells a story about what has taken place in an area during past geologic times. I learned then that preconceived ideas about how the geology of an area might be such and such, accompanied by ideas that certain processes or events couldn't have taken place, or that others must have taken place, often didn't fit with the story the rocks were trying to tell me.

As geologic mappers, we must follow the contacts, over hill and dale as necessary; we must check out, ascertain, and describe the textures and rock types; we must follow basic geologic principles, while observing obvious signs and vague hints in the rocks that point to the order of events as shown by the principles of superposition and cross-cutting relationships. If the rocks are telling us something unexpected—or something thought to be unlikely or even impossible—we must listen to them. For myself, geologic mapping became much easier after I was willing to give up my limited preconceived ideas about what I should find out there in the field.

Geology of the Conterminous United States, Digital version at 1:2,500,000 scale, courtesy USGS.

A geologic map is a thing of true beauty—although I don't really like the use of gray for Quaternary in this particular rendition of the geology of the 48 states.

Map courtesy USGS Geologic maps of US states.

Maps and Mapping Resources:

Geologic Map Day resources at AGI

FAQs about geologic maps at AGI

What is a geologic map? USGS at National Park Service

Introduction to geologic mapping, by the National Cooperative Geologic Mapping Program at the USGS

Geologic maps of US states at the USGS

Geology of the Conterminous United States, at the USGS

Nevada geologic map at the USGS

A puzzle of geologic regions at the USGS

The Basin and Range province at the USGS, Tapestry of Time and Terrain

Tuff All Over: ESW field trip by the NBMG on Saturday or Sunday, October 20 or 21, 2012

Yes, it's Earth Science Week, has been all week since the 10th, will be all week through the 16th. As usual, the Nevada Bureau of Mines and Geology is doing it's own thing for Earth Science Week: a one-day field trip, held both this coming Saturday and Sunday, the 16th and 17th. The field trip is called, "In Search of Tufa, Tuff, and Tough Rocks." Go to that link to sign up.

These field trips are always good, are open to the public, and often have several geologists besides the main field trip leaders along for question answering. I'm sorry to say that I won't be making it this year.

For anyone interested, whether going or not, the road log for the field trip is already available online, check out some great pictures of tufa domes! On the trip - or if you follow the trip guide at a later time - you'll see tufa, tuff, and some granodiorite (the tough rocks). You'll also travel across some old Lake Lahontan shorelines, northeast of Reno, NV, near Pyramid Lake.

Earth Science Week started yesterday, and I noticed that not a single thing is listed under "What's Going On" for the entire state of Nevada. (I also noticed in general that much of the Earth Science Week website is still focused on 2008, with many links either broken or linking to events and sites from last year.)

Actually, I've been a little bamboozled by Earth Science Week this year. It almost always overlaps with the Annual GSA meeting, which is of no concern to me in years when I don't go. This year, however, I am going, so I inconveniently didn't plan anything for Earth Science Week.

I belatedly noticed that the Nevada Bureau of Mines and Geology (NBMG) scheduled their Earth Science Week field trips for this last weekend, meaning that the field trips ran on Saturday and Sunday, October 10th and 11th. And I missed out! I have gone on these field trips on more than one occasion, and have found them enjoyable. They are open to the public, and kids, families, and school teachers are especially welcome. Local geologists from the Geological Society of Nevada (GSN), accompany the trip as informal field trip guides to help answer questions (and to learn more about new areas they might not have visited).

This year's field trip was called "Digging Deeper into the Comstock." An online road log is available, so you can take the trip on your own sometime (or at least part of it), whenever it is convenient.

Next year, I'm going to have to mark my calendar much earlier in the year. I had assumed that the field trips would run while I was away at GSA, so by the time the announcement came out, I had already made other plans. And, anyway, the last month turned out to be a little hectic in some ways.

Because I'm not doing anything for Earth Science Week myself this year, I'd like to point you to a few sites of interest:

• Kim at All My Faults are Stress Related has a few ideas, including:
• Donating to the Geobloggers DonorsChoose challenge, which is highlighted and described by Anne at Highly Allochthonous, and
• Michael at Through the Sandglass describes the Earth Science Literacy Initiative's (ESLI) nine Big Ideas in terms of, you guessed it, sand!

I hope you find something of interest!

UPDATE: This post has been submitted to Accretionary Wedge #21 on Earth Science Outreach.

Accretionary Wedge #21: Earth Science Outreach

The Accretionary Wedge for February is up over at Geotripper! Go check it out - lots of geological places to see around the world, including your own backyard.

Check it out!

In a continuation of a meme event that took place in the GeoBlogosphere late last year, Garry Hayes is hosting the current Accretionary Wedge - February, #16 - at his site, Geotripper:

What are the places and events that you think should all geologists should see and experience before they die? What are the places you know and love that best exemplify geological principles and processes?

Rather than create a new list of 100, or even 25, I thought I'd just mention a few places not on the original list, that I think should be considered.

Snake Range, Nevada: a place to collect mylonites.

1. See a metamorphic core complex - metamorphic core complexes are common in a belt in North America, from British Columbia south into Mexico, and also occur in other places in the world, including Slovakia, Greece, Turkey, Iran, Tibet, China, and New Zealand. One should see a metamorphic core complex, preferably as part of a tour or field trip, just so one can get involved in the lively discussions about how they form, but also in order to see and collect wonderful samples of mylonites!

2. While in Tibet, check out the Tibetan Plateau - just because it's there. It's the "largest, highest area in the world today" - and it was created by a magnificent convergence of two continental plates.

3. While in China, be sure to see the South China Karst, which is now a UNESCO World Heritage Site, and which contains some unusual rock formations formed by dissolution and re-precipitation of limestone: Guizhou Libo Karst, Yunnan Shilin Karst, and Chongqing Wulong Karst. I don't know of other similarly magnificent regions of karst that could replace this one.

Those are my three additions or suggestions. I have seen number one: several metamorphic core complexes in the western United States.

Accretionary Wedge #16: Is One Life Enough?

Here it is, seen first at The Ethical Palaeonologist and now at Clastic Detritus, Highly Allochthonous, and ReBecca's Blog, the countries and states I've visited:


visited 5 states (2.22%)
Create your own visited map of The World


visited 42 states (84%)
Create your own visited map of The United States

Not too hot on countries; not too bad on states, although many of those I have just passed through on an interstate or a pre-interstate highway. Not sure about Vermont.

States I'm sure I spent more than one day in a row in:

visited 25 states (50%)
Create your own visited map of The United States

States I know I visited by the time I was five (corrected 10-Jan-09 with the addition of Wyoming):

visited 16 states (32%)
Create your own visited map of The United States

Go here for music without much video.
Allman Brothers, Ramblin' Man, 1973 - based on a 1951 song of the same name written by Hank Williams - from their Brothers and Sisters album.

Taking a clue from GeologyJoe at Slingshot Thought, I realized that today is the first day of Earth Science Week! The theme this year is No Child Left Inside, so go out and check out something related to Earth Science. The official Earth Science Week 2008 website has quite a number of ideas.

If you happen to be in Nevada, and especially if you are in the Reno area, you can go on one of NBMG's Earth Science Week field trips, which will be held October 18th and 19th. If you are a geo-type, you can usually sign up to be an unofficial field trip leader. Either way, sign up and go! I will not be able to make it this year because of previous commitments (think: work), but know from previous experience that many of these stops are well worth going to!

UPDATE: Kim lists a number of contests for Earth Science Week, with deadlines coming up shortly - so get cracking if you're interested!

UPDATE AGAIN: MJC Rocks at Geotripper is plugging for taking children on geology field trips; Geology Happens takes some 4th-graders out on a field trip; Tuff Cookie has described Earth Science Week in great detail and with a lot of links, and Lee Allison at Arizona Geology thinks we should all do more for Earth Science Week next year.

Talk about anthropomorphism, volcanoes have now been labeled as evil by a certain non-geo blogger. Twice!

Bloggers of the geoblogosphere - Maria, The Volcanism Blog, and Chris Rowan - have come to the defense of the otherwise defenseless volcanoes of the world. After all, someone's gotta do it. Who's ever heard of a volcano hiring a lawyer? No need for that, though: we've got the geoblogosphere to the rescue!

It's all a question of balance, though. Without volcanoes, we would have no life. Without life we would have no extinctions. Without life, we would have no humans to bitch about volcanoes and extinctions. On and on, yada yada yada...

All I can say is:
Volcanoes of the World Unite! Don't put up with all this maligning of your no doubt pure intent!

I circled a large area on the above map (Ron Blakey's map) to show where central Nevada might have been located on the supercontinent of Pangaea in the late Triassic, about 220 Ma. I think that much of Nevada was under water in the late Triassic, or consisted of a bunch of islands, but maybe not all of it - maybe there was some solid ground here way back then. It seems like accreted and obducted terranes came in, then more came in, then more, then... [that's a quick summary of Nevada's early geologic history, and not a very rigorous one, as you might be able to tell!).

So, the large yellow circle is my approximation (guess?) of where Nevada was on Pangaea in the late Triassic.

This post follows on with several other GeoBlogosphere posts, starting with Chris at Goodschist and then several others including Callan at NOVA Geoblog and Brian at Clastic Detritus. You can compare my large, ungainly yellow circle for the approximate location of central Nevada with Brian's small circle for the location of the Bay Area and see that at least they overlap!

Oh, and at least one more geoblogger has joined in - Chris at Highly Allochthonous.

And another one: Hypocentre at Hypo-Thesis.

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

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

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

A few more references: Supercritical water and Hydrothermal Chimneys 

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

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

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

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

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

Accretionary Wedge #8: Earth Day the Geologists' Way

Well, Stan Keith is at it again, at least in making up new words that can be applied to either plate tectonics or mineral deposit formation. Unfortunately for all, the new word "Serpentosphere" can only be investigated, as far as I can find, by attending an upcoming meeting of the Geological Society of Nevada on Friday, March 21st in Reno, NV. Free beer is at 6:00 pm, dinner at 7:00, and the talk at 8:00. (Contact Kelly Parsons for reservations or more info, 775/323-3500, gsn@gsnv.org.) The talk is being authored also by Monte M. Swan, Martin Hovland, Hakon Rueslatten, and Hans Konrad Johnsen. Because the abstract has been published in a newsletter by the Geological Society of Nevada (GSN), I'll quote it below:

The Serpentosphere consists of an earth-wide nearly continuous layer (or spherical shell) of rock dominated by serpentine group minerals (serpentinite). The Serpentosphere is typically about two kilometers thick beneath ocean basins where it is mainly composed of lizardite. Beneath continents, the Serpentosphere is mainly composed of antigorite (alpine peridotite/serpentinite) and may be several kilometers thick. The base of the Serpentosphere coincides with the gravity and high-velocity seismically defined transition beneath both continents and ocean basins commonly referred to as the Moho. Beneath ocean basins and adjacent to spreading centers, oceanic Serpentosphere is continuously generated by the interactions of deep circulating marine composition water – partly in super-critical state –with harzburgitic peridotite in a process referred to as serpentinization. Conversion of the harzburgite to lizarditic serpentine under supercritical condition is texturally preservative and probably induces about 40% volume expansion. The volume expansion provides an excellent mechanism to expel and propel fluid products – including hydrocarbons – from the area of serpentinization to seep sites at the crust hydrosphere/atmosphere interface. A downward diffusing, super-critical serpentinization front is present beneath every ocean basin and is more active where it originally formed near oceanic ridge thermal anomalies. When ocean Serpentosphere is subducted beneath continental or oceanic crust areas, it converts to antigorite-dominated serpentinite rock (generally coincident with greenschist facies metamorphism). During flat subduction, the relatively lowdensity antigorite ‘floats’ and is underplated to the base of the continental crust at the Moho geophysical interface.

In effect, both oceanic and continental Serpentospheres reflect a deep ‘weathering’ process that consists of the interaction of deep crustal and oceanic, water-dominated fluids with the upper portion of a mainly harzburgitic peridotite at the top of the earth’s lithospheric mantle. The process is analogous to the formation of the pedosphere through interactions of the earth’s hydrosphere-atmosphere layer with the top of the earth’s lithospheric crustal layer. In this context, the Serpentosphere may be viewed as a thin membrane that separates water-absent, life-free abiogenetic processes in the mantle from water-present, life-related processes above the Serpentosphere in the oceanic crust.

The Serpentosphere has enormous and novel implications for four major geologic problems that are of current interest to the geologic and social community: the driving mechanism for plate tectonics, the origin of life, the origin of hydrocarbons, and contributions to global climate. A close relationship between trace elements in crude oils and serpentinite has been found. Migration of the serpentine-associated hydrocarbons to seep sites on the ocean floor and in subaqueous continental environments is essentially the base of the food chain for the biosphere and provides a nutrient and energy source for life in these environments. Heat, methane and carbon dioxide generated during the serpentinization reaction provide a major thermal and greenhouse effect to the earth’s hydrosphere-atmosphere system that is overlooked and underappreciated by the current global climate science. The ductility of the serpentine group minerals provides the tectonic “grease” that allows crustal plates to be able to slide and glide around on the earth’s crust at the Serpentosphere/Moho interface. Because Serpentosphere has been continuously generated since the beginning of geologic time it must be considered as one of the fundamental entities of our water-surfaced planet – the only water-planet we know of ...

Online references to this idea are scant, consisting of these two, and this interesting cartoon:

I won't analyze this Serpentosphere concept, and will just say that I find it interesting because it is related to flat subduction and the concept of hydrothermal hydrocarbons, evidence for which has been seen in the mercury deposits of the California Coast Ranges. Also, he is trying to promote a new model for oil exploration, which can't be knocked these days (unless it doesn't pan out). I won't be at the meeting, so will not be able to hear about this first hand.