Posted by: Alan Pitts | June 4, 2012

Glacial Striations

Here is a lovely striated and faceted clast that we encountered while on our 3-day glacial geomorphology project at field camp.

You can see that this clast was clearly worked by glacial action. The tiny striations are all carved into the rock by grinding against other smaller pieces of rock with in the glacier. Also, the rock has a really nice square shape to it, with faceted faces. This rock is nearly square as a brick, and shows all the signs of glacial sculpting.

Here is a quick annotation I drew to highlight the flat faceted faces and striations.

Posted by: Alan Pitts | June 3, 2012

Glacial mapping at Doo Lough

Here are a few photos from our 3-day Glacial Geomorphology field trip and mapping project at field camp in and around Connemara and South Mayo, Ireland.

This is what the camp faculty refer to as “Big Daddy” Cirque on the shore of DooLough. The lighting and cloud cover was really amazing that day.

Here is a look  down Doolough pass

Here is the group getting ready for a the trek up into the cirque.

Here you can see the prominent moraine which forms a very steep ridge made of glacial till.

Here is a look from on top of the moraine looking back down the hill. The reflection of the mountain in the lake almost appears to be a large gorge. I had a great conversation with some of the students imagining how exactly I  would parachute down into the gorge, if it were a gorge.

I like how you can see a tiny little delta forming at the mouth of the stream dumping sediment into Doo Lough.

This last one is of my little friend I met high up on the cirque walls.

Posted by: Alan Pitts | May 29, 2012

Folds at Fountain Hill Beach

Here are a few sights from our second field mapping area at Field Camp, Fountain Hill Beach (formerly known to the JMU field camp faculty as Omey Beach).

Here is an overview of the beach.

The above picture I made with the panorama function on my pocket size digital camera. I took several other Gigapans (which sadly Wordpress wont allow me to embed here) of the beach which turned out really good. I highly recommend you go take a look at them here . And be sure to click on the picture to zoom around and explore.

And here is a look at the lovely folds in the pelitic schist and psammite. These rocks are part of the Dalradian super group of metasediments which were deposited on the laurentian margin and subsequently deformed during the Taconian orogeny. I also included a few annotations because, well, annotated geology makes me happy and is a relaxing activity for me.

The last one is a of a picture of some Andalusite crystals I found, which indicate a low pressure low-high temperature.

Thats all for now. More soon.

Posted by: Alan Pitts | May 21, 2012

Boulder Conglomerate- Lough Fee

Here are a few pictures of the lovely boulder conglomerate from our mapping area at Lough Fee.

Here is a google image of our location, just north of Connemara National Park

Here is a look at the lovely view that I took using the panorama mode on my camera

Now- The conglomerate

I’m intentionally not giving too much description on this for two reasons; 1 I dont have enough time, I need to be in the van and driving the students to the first field stop in approximately 13 minutes. 2 I dont want to do the students the diservice of describing their rocks for them. Thats what field camp is for.

Thats all for now- more soon

 

 

 

Posted by: Alan Pitts | May 19, 2012

In and around Petersburg

Whoa. Geology Field camp is a lot of work, especially for this TA. Over the first few days I have barely found any time to write about my experiences here. The good news is that we are all still here and loving Ireland. From the students perspective, they have been jettisoned at least 5 time zones from their home, to a foreign country with little mapping experience and expected to map and describe rocks they have never seen. This has not been an easy first few days from them. From my perspective, they are doing a great job.

Here are a few pictures of the rocks and scenery around our facility, the Petersburg Outdoor Eduction Center in Clonbur, Ireland, County Galway.

View of Mt Gable and the driveway exiting the facility.

I really love the Center’s logo, I feel it really represents all that I love about this place; the mountains, forest, lake, and beautiful scenery. But if you really want to enjoy it, you gotta get your boots on the ground.

The shore of Lough Mask.

Egg-shell weathering of Limestone.

Fossils are quite plentiful in these Mississippian age, shallow marine sediments, like these crinoid stems

This last one is of my van, which I have been calling the “Flying Fortress”. Note; the “Coastal Self Drive” does not actually drive itself. I do, on the wrong side of the road. Yikes!

Posted by: Alan Pitts | May 13, 2012

Quick Trip to Wicklow

The trip to Ireland so far has been great, or as the Irish would say “Grand”. I’ve spent most of the past week hanging around in Dublin before field camp starts next week. Originally, I had grand plans for this week before field camp starts to travel the country on my own to visit and gigapan some of the great sites we will see during camp. But Ive had to reassess some of my plans due to constantly changing weather conditions.

Ive been talking with a lot of the locals about the weather and their perception on what is a normal Irish summer. Some say that summer hasn’t happend yet, others maintain that it already came and went in March. From my perspective, this is exactly the type of weather we experienced last summer; cold driving rain interspersed with a few hours of hard sunshine here and there. So for me this is pretty “normal”. Locals like to say that you get all 4 seasons in one day in Ireland, and that they are creating a 5th.

Earlier this week I took a quick trip to Wicklow to visit a friend and spend a day in her town. Wicklow is south of Dublin and is beautiful country. I had only a day in town but I managed to find some neat geology around.

Here are some lovely folded schist, used in construction of the old jail in Wicklow town.

This I found along the road in town and seemed to be in place

The next day my friends took me for a drive into the hills to see Glendalough, a glacial valley containing an impressive 6th century settlement.

Here is a look at the very prominent U-shaped valley which this settlement sits in.

We only had a few hours to play with before I had to catch my bus back to Dublin. I would have like to explore a little more and looked for clues of glacial movement. Another day I suppose.

On the way out we stopped in a little restaurant and I saw this painting, a depiction of the settlement in Glendalough during it’s hey-day. I took a crooked picture of it.

As a geologist, one of the things I personally enjoy about Ireland is the juxtaposition of new and old. Depending on who you ask, the scene above could be described as very ancient or very recent. In terms of human history, the settlement is very old, much older than any historic structures in my home state of Virginia. In terms of geology, the glaciers which carved this valley and created this beautiful landscape were very recent and younger than most of the geologic features I’m familiar with back home.

I’m hoping to squeeze out one more blog post before field camp starts on tuesday and I have to get to work (today is Sunday). Im starting to get really anxious for field camp. Sure, hanging around with my buddies in Dublin on this mini-vacation has been great fun (or as the Irish would say “great craic”), but I came here to do a job, and I am very excited to start working hard.

Posted by: Alan Pitts | May 8, 2012

My Irish Summer 2012

So here I am back for another summer in Ireland.

Last summer, as some of you might remember, I was here as a student to complete a 6-week field course run by James Madison University. Well, after working really hard last summer and maintaining 6 weeks of ceaseless enthusiasm in the field, the good folks at JMU asked me to come back this year as a Teaching Assistant.

I couldn’t be any more thrilled for this opportunity to continue learning and to share what I have learned in a field setting. I am also very happy to be working in my very first geology instructional(ish) position. For the most part, my duties will be focused on managing the students around the facilities; letting everyone know when their laundry day is, when they need to be down to set up dinner, and making sure everyone is getting along alright.

Aside from my duties at the facility I will certainly not shy away from helping students in the field and I am very eager to aid in this regard. Although I still consider myself a field student as well, I really enjoy working with less experienced students helping to develop their descriptive skills, and approach to field geology. Sometimes people just need to look at things in a different way before they can really understand and take ownership of the concepts. This is the type of thing I feel that I am good at; looking a things in a different way, making useful analogies and finding logical ways to solve problems. Field geology can be really stressful and scary for some, there is so much uncertainty and no book to consult for the right answers. I have learned that in order to be a good field mapper one must not be afraid to to trust their observations and make interpretations. I hope I can help this year’s crew cut through the stress so they can; make good descriptions, take good measurements and proceed with interpreting the geology.

With that brief introduction. Here is a quick rundown of where I will be going during my time in Ireland. Rather than explain it all in words, I drew a little map.

This is a general geologic map of Ireland, available through the GSI, which I modified to highlight the plan over the next 7 weeks.

It is worth noting that I made no special attempt to place the markers in their exact location. I also made zero attempt to  match my dashed yellow lines with the actual path of roadways, so these paths could be much more (but probably less) direct. There are also several other little logistical points that I didn’t include on this map to keep it simple.

1- Arrive in Dublin. This is where I am right now. Mostly just relaxing and taking in the culture before camp starts

2- Belfast. Here is where I will meet the other instructors to get our field camp vans.

3- Galway. After collecting the students, we will drive to the lovely little town of Clonbur in County Galway, this will be our home for the next month.

4- Clare. After leaving Clonbur, this is where we will spend two weeks studying the stratigraphy of the Clare Basin and (depending on each student’s choice of track) Hydrology. We will also visit the Cliffs of Mohr and surely take in some great traditional Irish music during free time.

5- Northern Ireland. A short trip to see the Giants Causeway, Cliffs of Ulster and maybe some castles

6- Cork. After field camp ends I will be on my way to see the great Irish folk musician Christie Moore live in Concert with a few Irish friends!

7- Dublin- Back to where I started to relax and decompress for a week before coming back home to the US.

It seems like a long trip, but if it is anything like last year, I know it will all be over before I know it. Since I wont have the heavy work load of creating maps and writing reports like last year, this year I am challenging myself to blog as much as possible.

Posted by: Alan Pitts | March 12, 2012

Two for One: Fold (on a fold) and Fossils

Here are a few photos of some really neat ( and when I say neat I mean totally awesome) folded sedimentary strata from the Valley and Ridge province in West Virginia. The work I’m doing in WV is part of a larger and really cool project I’m working on with Callan Bentley named MAGIC, or the Mid Atlantic Geo-Imagery Collection. As geologic MAGIC workers our goal is to build a massive online collection of geo imagery to share with people like you (student/amatuer/professional consumers of online geologic information) to enjoy, investigate, and learn from. Right now my contribution to the project is a job of searching for the best outcrops around and recording them in all their brilliance using GigaPan photography.

This location is a prime road side stop if you happen to be traveling along the new Route 55 ( also known as Corridor H) in West Virginia. This enormous strip of asphalt, blasted through miles of pristine beautiful WV mountainscape, happens to reveal some of the best exposures of lower Paleozoic sedimentary strata anywhere in the mid-Atlantic region.

Here is a photo of the locale along with my initial interpretation annotated.

I think this is part  Tonoloway Formation, a Devonian tidal carbonate unit.

For a better look at this outcrop and the complex folding, please go take a look at the Gigapan I took of this location, wordpress wont let me embed it here, so until I figure a way around this, links will have to do. Using the gigapan as an investigative tool from home, My friend Aaron and I identified several folds in the “I have no idea” section  that are worth taking a look at. (Make sure to use the zoom controls to get up and close with the outcrop!)

These folds are outcrop-scale expression of the intense regional deformation experienced by these rocks during ( most likely) the Alleghenian Orogeny, when Africa collided with North America to create Pangea.

While the Gigapan robot was doing its job of systematically guiding the camera through 170 photos to build the stunning Gigapan of this location ( which if I may reiterate, you should really go see…..please) I walked across the highway to inspect the outcrop.

On the ground I found this sample littered with tiny lentil-shaped fossils. These are Ostracods, most likely Leperditia, arthropods which were quite abundant during the  Silurian-Devonian.

I also found this sweet hand-sample-size parasitic fold.

Here is another version of the image with some annotations to highlight the folding.

As if this fold on a fold wasn’t awesome enough, I think I found some fossils on it too. Do you see them? It wasnt until I was back home looking at my photos that I noticed them, but I think there are some more Ostracods in the upper left corner.

Here

Looks like some more little lentil shapes which are lighter in color than the surrounding rock.

As you can see in the middle-right of the photo that this fold, along with the rest of the surround rock is weathering at a rapid rate. Without much encouragement, this guy basically fell off the wall and into my hands. So I brought him home.

Here are a few more pictures of the fold once I cut it at the GMU rock saw room.

Here is the original face, rotated 180 degrees from the original orientation ( upside down).

Now here is the other side which was cut:

When this guy came out of the rock saw, Aaron and I simultaneously let out an uncontrollable “Whooooooaaaa!!!” lasting for nearly 10 seconds. It was a really funny moment for us and one in which we realized that we are both certified geology nerds. You just can’t fake that kind of excitement.

One of the other things I found, while inspecting this rock on all sides, was some great slickenlines. Slickenlines are tectonic structures which form as rocks slide past each other. Slicks as they are commonly called, are useful structures for understanding motion along faults and slippage planes. In this case,these slicks were formed as “flexural slip”.  Flexural slip occurs as sliding along bedding planes as a result of folding. I found this diagram on flexural slip to help explain the process ( and to help me finish the post sometime soon).

Here is the same image from above with some lines and arrows to mark the direction the adjacent rock was moving.

I always enjoy rock samples with multiple subjects of interest. This one is loaded with fun structures that I was able to identify myself and Im sure if/when I show this to some of my geology advisors and collaborators that they will find more. What do you see here ? Anything that you find interesting I missed? I’d be happy to hear any alternate interpretations.

Posted by: Alan Pitts | January 5, 2012

My Geology Superpower

Last spring, I read a hilarious post by Callan Bentley, in which he displayed his structural super power, which would be to shoot en echelon tension gash arrays from his fingertips. Which is pretty cool, if you are into that sort of thing

After thinking about this for a while, and since no one got me a structural geology super power for Christmas this year, I thought I’d go ahead and spell it out.

What I would like is really pretty simple, just the ability to generate a blazing-hot plumose structure which I could launch from the palms of my hands in a spectacular, fiery display of geologic comprehension. Not only would this be a useful method to drive off  my geologic arch-enemies, who continually sabotage my pursuit of science by obscuring good outcrops (lichen), but it could also be handy for highlighting the direction of joint propagation.

Here is what I’m talking about.

Yeah, I know. Pretty sweet, right?

Posted by: Alan Pitts | December 10, 2011

Not Necessarily Geology Mountain Bike Guide: Part I

Welcome all, to the first installment of the Not Necessarily Geology Mountain Bike Guide.

The NNG Mountain Bike Guide is an idea that has been bouncing around in my head for a few years now. Basically, the concept unifies two aspects of my life that I’m really passionate about; geology and bicycles. I started thinking about this back when I lived in San Francisco, California. I was enjoying an extended summer break, employed as a professional (a term that is certainly debatable) bicycle tour guide. On my days off from “work” I liked to pedal across the Golden Gate Bridge into Marin County to explore some amazing geology and enjoy some world-class mountain biking. As a tool for exploring the area, I purchased a mountain bike guide, which contained a wealth of useful information leading me to outcrops and points of view inaccessible from roadways. During this time I also tried to read whatever I could find on Bay Area geology to familiarize myself with the complex regional picture. After spending a lot of time reading field guides in both geology and mountain biking, I thought I would like to combine the two concepts. So here it is.

The first in this hopefully long series of posts is from Conway Robinson State Park in Gainesville, Virginia.

This hidden gem of a park is literally a stone’s throw from Rt 66 in Northern Virginia and just over 30 miles from Washington DC. It is one of the few parks that allow mountain biking in the area. For me, this place has long been a wooded refuge from the sprawling suburban colossus that is Northern Virginia. Taking a ride at Conway Robinson is an easy way to escape all the traffic, McMansion town-homes and chain restaurants, which have become all too common around here. Or, if you’re the type who would like to get away from the present reality in space and time, if only for a few hours, you can do that too.

Take a visit to Virginia’s Jurassic Park.

It is pretty unlikely you will find any dinosaurs here (living or non), nothing like the depiction of the Jurassic Period made famous in the Classic 1990s film. Yes, there were dinosaurs on Earth at that time, and there is even good fossil record of dinosaurs nearby, just not in this park (that I know of). This post has nothing to do with dinosaurs because… well, personally I find the dinosaur inhabitation of Earth to be far less interesting than the tectonic history during that period. There, I said it.

Before we get into the mountain biking, here is some background on the tectonic history and regional geology of the area.

The following 3 images are from The Paleomap Project by Christopher R. Scotese. This is a great resource for visually exploring reconstructions of global Plate Tectonic history.

This first image is of the Earth during the early Triassic period, Pangea is seemingly still a happy marriage of the continents. The North American Plate is still in contact with the African Plate. However, you can see some shaded areas in the middle, which likely represent the beginnings of the end of this continental assemblage.

The next image, also from Scotese, is a reconstruction of the early Jurassic period. This looks pretty similar to the first image but actually a lot has changed, especially on the North American/African boundary.

In this image the spreading is now very visible. The northern end of the rifting zone is opening up like a zipper and has admitted seawater where the new Atlantic Ocean is forming. Africa and North America, now mostly separate from each other, are spreading away which will eventualy result in their present placement on the globe.

The last picture in the 3 photo sub series (also from Scotese) is the from the late Jurassic, 152 million years ago.

At this stage the Atlantic Ocean is established and on the way to becoming a major oceanic basin. The view at this stage in Earth’s history is beginning to look more like the Earth we know today. The continents are starting to take on their current shapes and there are more recognizable features, like the Atlantic and Pacific Oceans.

Now back to Virginia.

Conway Robinson is located in Virginia’s Culpeper Basin, a tectonically induced rift basin, which was activated during the early stages of the break up of Pangaea in the Triassic. It is basically a giant tear in the crust that failed to become the new Atlantic Ocean, and remained attached to the North American Plate. This basin, along with several others of similar age along the east coast of North America, filled with sediments and flood basalts.

I have previously written about a conglomerate from the Culpeper Basin, in which I described some local geology. Also, last year I wrote a rather cheesy post using pieces of my sandwich as a rudimentary analogue for the extensional strain which formed the Culpeper Basin. Though, one of these posts may (or may not) be good background reading for this, here are a few recycled images for those who did not read those posts.

This graphic is just a simple Google Map image of the area, which I annotated to mark the approximate location of the Culpeper Basin.

Here is a general cross-section of the Culpeper Basin by C.M Bailey of The College of William and Mary. The two units that are featured inside Conway are Jurassic Diabase, shown in red, and Triassic/Jurassic sediments, shown in green.

There is a lot of useful information in the above diagram. Illustrated are the structural boundaries of the Culpeper Basin, both of which are normal faults, creating a down-slumping block of crust. The action along these faults created space for sediments to be deposited (TJs). As spreading continued, eventually mafic feeder dikes (Jd) cut through the older sedimentary units delivering flood basalts to the surface.

Now here is a closer view of the park itself. The main trail is marked in red and follows the perimeter of the park.

I created this trail map using MyTracks, a wonderful and really useful app for my Droid smart phone. I just started the app, which tracks GPS location, tossed my phone in my bag and rode the trail. The app does the hard work calculating the moving statistics, all I had to do was enjoy myself and look out for rocks!

The trail marked above is actually the longest possible loop around the edge, which is probably several trails and there are several more trails which cross the middle of the park. I plan on improving this map to include more specific trial info and updating this post. Just as soon as I get more time to ride and record more trail data. There are nearly 7 miles of riding within the park. So there is a good amount of area to explore, but not enough to constitute any real danger of getting lost. As you can see the park is basically encased by highways, on ramps, off ramps, neighborhoods and golf courses. You can basically experience the joy of getting lost (and found) several times in one afternoon.

As far as the difficulty of the mountain biking, it’s mostly moderate with a few difficult single track sections near the backside of the park. One of the things I’ve come to learn about the Culpeper Basin (also visible in the “outline of the Culpeper Basin” graphic) is that it is pretty darn flat, not a lot vertical relief. So there are not many sustained climbs or long miles of technical downhill.  Dont worry though, there are lots of smaller hills to make the ride fun and challenging enough for those looking for good workout.

As far as the geology goes, it’s pretty great.

Here is the same trail map image from above, which I imported into Google Earth, paired with the USGS Virginia State geologic map overlay (available here) and added some additional annotations to indicate the bedrock geology.

You can see in the above image, the park is underlain by two general rock types. The red is the Jurassic Diabase and the light green is Triassic shale and siltstone. Most of this is covered by vegetation and soil, but there is one really good outcrop of Jurassic Diabase near the “backside” of the park marked on the above map.

Here are a few pictures of the diabase outcrops.

Some of these exposures appear very columnar to me, like the one above and the first picture featured in the post. If they are in fact columns, then they owe their existence to the cooling of this once molten rock. Columns form (mainly) in igneous rocks (usually basalts) as contraction fractures. As the rock cools it shrinks and fractures in order to accommodate the volumetric change.

Here is a link to some other pretty world-famous columns I saw last summer in Ireland at the Giant’s Causeway.  Also here is a post by my former Structural Geology professor Callan Bentley, about some great columns in meta basalt in Shenandoah National Park.

This next picture is an up close look at the vertical faces of these “columns”. Notice the horizontal fractures perpendicular to the vertical joint faces. Or maybe these are arrest lines, I’m not sure really.

Here is an annotated version of the first diabase photo illustrating the relationship between the vertical joint faces of the column and the horizontal fractures.

Here is a look at a one of the fractures, notice the zig-zag shape of the fracture and the overwhelming lichen coverage.

And here is a look at a fresh surface. You can see the “salt and pepper” look to the rock. The pepper being black clinopyroxene and the salt, white plagioclase feldspars.

At several points the trail crosses obstacles which represent the meeting between geologic consideration and mountain bike trial description. A contact, if you will in both a metaphorical and geologic sense.

Here is what I’m talking about. While most of the riding is pretty tame, at points the trail crosses what local mountain bikers call “rock gardens” ranging from 10-50 feet in width.

These rock gardens are made of rounded and weathered pieces of the Jurassic Diabase and outcrop as linear features cutting across sedimentary units. However, I imagine they have a more tabular nature in the subsurface. I think these could be the base of feeder dike systems that supplied the basalt flows on the surface. Or another idea is that they indicate the geometry of the igneous body and how its shape influences the exposure. I guess I’d have to get off my bike and map these features in greater detail to get closer to the answer.

On the bike this can actually be a pretty treacherous crossing,  plenty of opportunities to scrape your chainring or bash your foot into rocks. The best way to handle these is; try to pick a line on the approach, maintain decent speed, and keep your weight centered on the bike, you should cruise right through. Or you can just get off and walk for a bit.

I took the two photographs above a few years ago with my long-lost favorite bike. Don’t let the drop handle bars and “painter’s blue” bar tap fool you, that is no road bike and certainly not a work in progress. That, my friends, is a Surly Cross Check, and pretty much an indestructible swiss army axe of bikes. The Cross Check is perfectly suited for both road and trail, although not ideal for serious single track. Unfortunately this fine machine was stolen from me two summers ago. The culprit is still at large.

One more picture to finish this up. I was lucky enough to meet this little fellow on one of my trips who I thought was worth featuring here.

Additional Links:

The Virginia Department of Forestry page on Conway Robinson

Mountain Bike Trail Reviews for Conway Robinson

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