Tags » Geology

 
 
 

Celebrating the Flagship R/V Folger

Categories: Midd Blogosphere

The sunny, breezy day was made to order as friends, family and former students gathered to celebrate oceanographer and past professor David Folger on the shores of Lake Champlain. The shining focus was the spectacular and highly technological newest floating laboratory, the Research Vessel David Folger.

In noting what tremendous opportunities this new facility will provide, President Liebowitz underlined the importance of both the sciences and experiential learning, while others, including Lake Champlain Maritime Museum director Art Cohn and CEO of Terry Precision Cycling Liz Robert ’78, offered enthusiastic remarks on the benefits for the local community. And former student Debbie Hutchinson Gove ’74 shared memories and reminiscences from other classmates who couldn’t be there. Middmag was on hand to capture it all.

A New Vermont Geology Map

Categories: GIS, Midd Blogosphere

I’m a sucker for blogs and websites that send me scrambling to a dictionary, and recently I’ve come across a good one. Here’s your word for the day-odonatist. I’ll wait here while you look it up.

Back? Good. The site was The Daily Wing, an outdoor blog focusing on winged creatures, such as birds and dragonflies. (that’s an odonatist, if you were lazy and not terribly curious, a person interested in dragonflies, of the Odonata group. Good luck using that in your next conversation.) Bryan Pfeiffer, the author, writes all of the posts, and shows some of his amazing photography. It’s a gorgeous blog.

And like my blog, it seems like many things interest him. (Unlike my blog, he updates his more frequently. No excuses here-I got my house painted this summer.) What caught my eye was a post on the new Vermont Geological survey map, with the awesome title of “A History Expressed in Stone”.  The map, published by the state Vermont Geological Survey, is over 30 years of work, and shows major bedrock formations across the entire state. I want to get the paper copy, but our house lacks wall space for the 3 6 foot by 5 foot sheets, and my cave of an office wouldn’t even fit one.

So I’ve downloaded it, and the three PDF’s would blow my entire Papercut budget for the year, so I’m holding off on that. I’ve also download the shapefiles for Google Earth and ArcGIS, but am waiting to really delve into that this winter.

As a landscaper, something I’ve learned the hard way is that you just can’t fight geology. I’ve tried over and over to grow rhododendrons, holly, and other ericaceous plants on the MIddlebury campus, but our high pH soils just won’t let me. And the reason for that? The bedrock.

Lovely Filth

Categories: Midd Blogosphere
It’s not often that I get to make direct connections between an exhibition in the galleries and the collection of public art that we have on permanent display around the campus. The opportunity is probably there more often than I’m aware, but during my tenure anyway, the times when the similarities have been palpable have been rare. This spring, with Environment and Object • Recent African Art on view in several of our galleries there’s a theme that’s begging to be explored both inside and out. And it’s totally rubbish. Continue reading

Nature Geoscience {new journal access}

Categories: Midd Blogosphere

Nature Geoscience is now available to the Middlebury College community.

Some of the topics covered in the journal include: Atmospheric science, Climate science,  Geoinformatics and remote sensing, Geomorphology, Glaciology, Hydrology and limnology, Mineralogy and mineral physics, Oceanography, Palaeoclimatology, Planetary science, Seismology, Space physics, Tectonics, and Volcanology.

Geoscience is best accessed through the journal’s website, where you can sign up for email alerts and view tables of contents from recent issues.  Its contents are easy to search in GeoRef, the major research database for the geosciences.

Be sure to bookmark the full url for off-campus access:
(http://ezproxy.middlebury.edu/login?url=http://www.nature.com/ngeo/archive/index.html)

Geoscience will also be available through MIDCAT,  the Journals A-Z list, and Summon*.

*At this time, full-text indexing of Geoscience is not available through Summon. 

Planting Dolomite

Categories: Midd Blogosphere

One of my regrets in my college career lies in one of my favorite courses, Intro to Geology. I took the class Pass/Fail, which left me with just enough knowledge to totally confuse the hell out of myself. I loved the class-I remember the labs most of all. Like going to the Lake Mansfield Trout Club, in Nebraska Notch at the base of Mount Mansfield, walking along the top of a lateral moraine in the woods, and making a hard left as the moraine turns into a terminal moraine.
I don’t remember much of the classwork, however, nor the tests. I still have the textbook we used, and I’ve been meaning to re-read it for the last 20 years since the class, as I found it fascinating. Geology is a language all its own, and not being fluent, or even knowing how to ask to use the bathroom, makes it difficult to read.
So Middlebury, be careful what you wish for, wanting a pass/fail option. Would I enjoy reading about geology if I had a stronger foundation in it, rather than skimming a class for an easy pass? I know I certainly would find it less frustrating, and the month plus gap in my blog writing would have been quite a bit shorter as well.

The other problem with geology, besides the language, is understanding time. We understand hours, minutes, days, weeks, even years, to a point. Humans can understand a generation or two, but go as far back as even 200 years, and time becomes irrelevant. How can we understand 4, 5, even 8 generations ago? I had a many greats-grandfather burned at the stake for witchcraft, but aside from creeping me out I can’t comprehend that far back.
And geology? Forget about it. The unit of time in geology is MYA, an abbreviation for Million Years Ago. The fossil record talks of rocks formed 200 million years ago, for example, but what does that mean? The Green Mountains were origniannly formed 450 MYA, but that’s as hard to grasp as 450 years ago, 70 years after Christopher Columbus ‘discovered’ the Americas.

I’ve planted many trees and shrubs here at Middlebury, and I love it, but planting rocks always seems to stick out in my mind. This fall I got to plant another. Dr. Peter Ryan, a professor of geology here at Middlebury (and excellent guest blogger) taught a course this summer for the alumni college called Vermont’s Geological Landscape: From Continental Collisions and Mountain Building to Groundwater and Streams. One of the field trips was to Pike Crushed Stone, up the road from Middlebury in New Haven, Vermont, and the source of much of our gray stone we use landscaping next to buildings on campus. While in the quarry they found a piece of rock with enough interest that Alum Paul Diette  generously donated transporation to move said rock up to campus, where we ‘planted’ it on a leftover square of concrete up near Bicentennial Hall for future classes to admire.

I’ve no idea why the concrete was there, but I think it was a piece left over from the old observatory that was up on that section of campus.
I thought the site appropriate, for several reasons. It’s proximity makes for easy teaching (not that the geology labs I’ve seen walking around have any fear of travel), but the a goal of Bicentennial Park is local trees and shrubs, so local rocks seem a good fit. I dream of filling the area with local rocks to sit upon, a nice contrast to Smog.

Paul has named the rock Diette-Ryan New Haven Iapetus Ordovician Seafloor, a pretty big name for a relatively small BFR, but was my lauching point into researching just exactly what this rock is. I’d always called this type of rock by it’s local name, Panton Stone. This limestone rock is used quite a bit locally in landscaping, as the pretty blue gray color and blocky fracturing make it natural for making stone walls, like a small wall north of Allen Hall next to the Atwater Dining plaza. Or better yet, look at the huge blocks of stone the next time you are out front of the Davis Family Library. Look close. You’ll notice fossils, lots of them, scattered throughout the stone, and this provides a convenient, if difficult way to age the rock.
Our new rock doesn’t have a lot of exposed fossils, and the couple showing only confused me further researching that. So instead I cheated, and went to the Vermont Geological Map to look up more specifically the type of rock, and a closer date.
As near as I can tell, this limestone is a ‘Beldens Member’ of Dolomite, dating it to about 480 MYA. The lack of many prominent fossils, probably lost in deformation and metamorphism, are good clue for age. The exposed ledge below Gifford Hall is probably in the same member family as this rock, writ large.

Vermont 480 MYA was a tropical paradise, like the present day Bahamas or Arabian Sea. Tectonic forces were pushing Vermont slowly to where we lie today, but back then Vermont was a shallow tropical sea,about 20-30 degrees south of the equator.
We sat in the Iapetus Ocean, forming part of a continent called Laurentia, comprising of our present North America Craton, combined with Greenland and parts of Scotland. (Iapetus was the father of Atlas in Greek myths, one of the original titans, and the Iapetus Ocean is the father of what we now call the Atlantic Ocean, named for Atlas.) Geologists have named this Ordovician time, in the Paleozoic era. The name comes from the British geologist Charles Lapworth, who in 1879 named the era for rocks found in Scotland.
Ordovician time was preceded by the Cambrian era, which saw life on earth diversify and explode into the many phyla we see today. Life in the Ordovician time continued to flourish, even as it was doomed at the end of the era in the Ordovician-Silurian Mass Extinction Event, the second largest (of five) such events we fellow earthlings have gone through.
Land wasn’t very interesting, mostly algae and mosses, but the calcite sea was an explosion of creatures, forming some of the earliest reefs. Around 480 MYA, when our rock was formed, the ocean was thought to be about 45 degrees Centigrade, limiting the amount and diversification of creatures, and therefore our fossils in the rock. The air cooled around 460 MYA, and more creatures arose, (http://www.anr.state.vt.us/dec/geo/foschamp.htm),filled with calcium rich creatures with hard exoskeletons, slowly dying to form what we now see as a hard limestone rock. Maybe we can see some foreshadowing, as carbon dioxide levels were 14-16 times higher in the atmosphere than present day, and high sea levels covered much of the continents in sea water. The globe was mostly ice free.
So for millions an millions of years, sea creatures were born, died, and fell to the shallow sea floor, slowly building the gray rock we move today.

Streaked throughout our rock are white lines, pure calcite precipitated out and laid down in cracks in the sea floor. A couple of fossils adorn it, although aren’t easily identifiable (know what they are? Post in the comments please!).


As well as a bump. The bump may be a piece of Chert, a poor cousin of flint, formed when silica replaces calcium carbonate.

Fancier cousins include Opal, Agate, and Onyx, while our possible chert probably wouldn’t even make a good arrow head or ax, an early use for chert.
The best feature of the rock is the fossilized waves seen across the top. Imagine being a kid the the edge of the Iaptetus, one of those days when the tide was very low, and seeing how the waves formed ridges along the surface of the sand. The tide rises again, water levels return to normal, and a new shelf deposit of rock starts to form, hiding the wave marks, that are only exposed again by the quarrying process 480 million years in the future.

So, as near as we can tell, the rock dates to somewhere between 480-460 million years ago, but we are still stuck with the concept of time. That sounds like a long time ago, but so does breakfast at times. Paul put it best, giving a concrete time example to our rock, and a poetic end to the post.
Our sun rotates around the center of the Milky Way Galaxy, slowly, taking somewhere between 225-250 million years to make one rotation. Humans, as a species, have made 1/1250 of a trip. Our rock, two whole trips around.

McCullough Plaza Rocks

Categories: Midd Blogosphere

A new category in the Middland blog, and a guest post to boot. I’m sure most of you have seen the new plaza at McCullough, but have you noticed the rocks out there?

I’ll confess the plant world almost lost me to geology in my UVM undergrad career. I’ve always loved it, and have the well worn Golden Guide to Rocks and Mineralsfrom my grade school days to prove it. Plants won, though, but I still work in rock whenever possible. And there is plenty of it at Middlebury, if you know where to look. In fact, I bet you see rocks all the time, and don’t even really think about them. In the landscape department, we call them BFR’s.

We use them all the time as impediments to parking, keeping cars off the paths at ridgeline, and, in the case of the McCullough plaza, as seating. Big F… Rocks are easy, relatively cheap, and easy to move by hydraulics. Not so easy to move by person, although some team rolled one out into Adirondack Road this fall. I don’t totally know which quarry they come from, but they are all well rounded, meaning they come from a quarry probably off of route 116, pulled out of the sand. The round nature comes from being pushed along from glaciers, and they were deposited in the sand before rolling into the Champlain Sea.

When I was meeting with the Master Plan committee out on the site of the plaza this summer, we were discussing the lack of seating around campus (a perennial problem), and John McLeod suggested large rocks. I immediately thought of some of my favorite BFR’s around campus (yes, I have favorite ones), and scheming of a way to get them there.

Once there, I contacted my friend Peter Ryan, and he graciously walked over and identified them for me. Following is his email back to me, with pictures. Hopefully when you run out there to look at them the snow will have blown off them. I’ve learned it’s quite a bit harder to take a good picture of a rock then it is to take one of a plant-go figure…

Breccia Near Entrance

Breccia Near Entrance

“The one closest to the entrance is a carbonate breccia, full of rock clasts with sizes ranging from a few millimeters to dozens of centimeters (perhaps from 1″ to nearly a foot in diameter), in a matrix of carbonate mud. How did it get that way? Breccias often form when rocks are ripped apart in fault zones, but another common way, especially with carbonate rocks, is cave collapse. Other types of erosion can also form breccias, but my guess is that this one is related to cave collapse. When sea level drops, it leaves carbonate rocks exposed to erosion, and the way that they erode chemically is to form caves… this is what has been happening in Florida for the past 2 million years, since sea level dropped and exposed the Florida peninsula. When caves collapse, the form sinkholes full of rock chunks. Ultimately, the source of the brecciation in this particular rock is hard to say for sure not seeing it in context with wherever the glaciers ripped it from.”

Quartzite

Quartzite

“The grey rock is quartzite, a metamorphosed sandstone. Vestiges of sedimentary layers (bedding planes) are visible as wavy black lines– nearly vertical and oriented East-West.”

Mudstone of Questionable Lineage

Mudstone of Questionable Lineage

“The third one, the rusty rock, is intriguing. There must be pyrite (iron sulfide) in the rock that is weathering (oxidizing) to iron oxide, producing the characteristic orange-red staining. It is hard to say exactly what the original rock is, maybe a mudstone…”

Thanks to Peter for filling in on everything I’ve forgotten from Intro to Geology-maybe I’ll sneak back in a geology class here some year. I wonder if one of his colleagues wants to positively identify the mudstone, and (hopefully) give him a hard time. Although, I’ll be the first to admit I run into plants I don’t recognize all the time, and rocks are admittedly quite a bit harder. (sorry about that pun)

 I’ll write about the plants at McCullough in a later post-the microclimate in the area let us use some fun plants.