Showing posts with label #fieldworkfail. Show all posts
Showing posts with label #fieldworkfail. Show all posts

Monday, October 24, 2016

Field Work Fail: For Want of a Flashlight

Hello Dear Readers!

The Strange Woman has been very busy as of late: collecting additional data for a paper that is the second to last paper to come out of my doctoral thesis. These last two papers are the result of the data at the end of my analyses showing me something cool that I had no time to expand on for the thesis. Sometimes research does that to you: sometimes discoveries have their own schedule. I'm also doing other things that I'll hopefully be able to write about in the future. Right now I'm in finger-cross mode with those things.

This is to say that I am still not ready to post the results of our summer's work at the Six Peaks Dinosaur Track Site. What I can do is show you a video we had done on the site. Here is a teaser for you!



I will share a dinosaur track field work story with you. This one dates back to 2011, and tells the tale of how we spent the night in a pile of leaves at the end of October in northeastern British Columbia.

***

The best laid plans of rodents and researchers...

Fieldwork in the Peace Region of British Columbia is not simple under the best of conditions, with the best conditions being fair weather in mid-summer. There are practical reasons for this. Materials don’t set well in cold or wet conditions. The ground is either too wet (for the spring) or too frozen (for the fall and winter) to safely remove fossils. Many times the weather renders the conditions too dangerous for field crews. This is why the paleontology research field season is short in the North. The PRPRC’s typical field season runs from June-September. If the snow and sub-freezing temperatures permit it, we’ll do short excursions well into the first half of October. It’s an exceptional discovery that will bring us into the field in end October or early November.

This is the story of one such exceptional discovery.

The site was discovered by a regional guide-outfitter, Aaron Fredlund, in 2011. He had come across a small exposure of grey sandstone sticking out from under a hill of Ice Age silt, mud, and boulders. Being an experienced tracker of modern animals, it didn’t take Mr. Fredlund long to notice the large, three-toed footprint and identify it as the track of a large meat-eating dinosaur. It also didn’t take him long to reason that, if he cleared some of the debris off of the rock in front of the footprint, a second footprint could be uncovered. He was correct. The two images were immediately reported to me, Dr. Richard McCrea, and Dr. Charles Helm. A combination of the track type (large theropod) and the age of the rocks (Late Cretaceous, approximately 72 million years old) led us to identify these footprints as those of tyrannosaurs!

Tyrannosaur footprints were not unknown to science: “singleton” footprints have been reported from the Late Cretaceous (Campanian - Maastrichtian) deposits from the US, Canada, and Mongolia. However, what palaeontologists were missing was a trackway: a series of footprints made by one animal. Isolated footprints are like finding an isolated dinosaur bone, while trackways are like finding a complete skeleton. A trackway of a tyrannosaur would provide a tonne (pun completely intended) of information on how this tyrannosaur moved when it was alive. Tyrannosaurs are the best-known dinosaur predator, but their footprints were the least well-known. This site had the potential to change all that.

At the time of reporting, both Rich and I were out of town. Charles made a visit to the site with Mr. Fredlund in our absence so he could report site conditions and access. There was no GPS data taken during the visit (one of those frustrating “I can take you right to the site” situations), Charles reported from the site visit that the locality was both treacherous and tricky to access, and would require an ATV to haul in the research equipment safely. In short, we would need a guide.

Fast forward to October 23, 2011. Charles had a break in his busy schedule to visit the site with us. This was our only opportunity to get the site documented and replicated before the end of 2011. We were starting to head into winter: there was no snow yet, but the daytime temperatures were not above 10°C, and the nighttime temperatures were hovering around and just below 0°C. We could not physically remove the trackway, so we had to make a silicone mould (or peel) that would be used to make an exact replica that could be housed (and studied) inside during the winter. As difficult as fieldwork is, cold exacerbates all difficulties. Since silicone doesn’t set up in cold settings, we had to both mould the trackway and heat the silicone so that it would cure properly. This was a large trackway: the two exposed footprints covered a distance of over 2 meters long, and almost a meter wide. We would need A LOT of silicone. Silicone is an expensive molding material, but this site was worth it.

We spent that week gathering silicone, mixing buckets, brooms, brushes, documenting equipment, and all of the gear we would need to keep the silicone peel warm enough to set: tarps, propane tanks and heaters. Me, Rich, and our field technician Tammy Pigeon had all of the field gear ready to go and loaded into the ATV on Friday. We were scheduled to leave Sunday, so we thought we had a full day (Saturday, October 23) to gather our personal field gear, which had been all packed away for the winter.

We got a call early Saturday morning. Charles’ schedule had changed: could we possibly head to the site that morning? We scrambled to throw together our personal field gear. An hour later we were ready to go...or, at least, we thought we were ready.

Cue ominous music.

We followed Charles out to the “trail head”: a labyrinthine series of decommissioned logging roads long overgrown with dense brush. We scouted the best path for the gear-laden ATV among the bogs, pits, and tumbles of burnt log piles. After a long while we reached the top of the hill: at the bottom of the steep slope was the humble little rock exposure containing the tracks of one of the most famous and charismatic predators ever known.

NOTE: there will be very few pictures of the trail down to the site and of the overall site. This site is still vulnerable to vandalism and general people nastiness that all of our publicly accessible sites have experienced. The selfish actions of a few do ruin things for the many.

Once we uncovered the camouflaging coating of rubble from the track surface, Tammy and I set to readying the track surface for the silicone mould. We were expecting to have to do a bit of digging, brushing, and wiping. What we were not expecting was to have to clean a 30 cm layer of kaolinite (clay) out from the all of the nooks and crannies of the footprints. This clay was stubborn: it required several washes and (soft) scrubbings before all of the clay was removed from the footprints. Removing the clay coating from the surface revealed small skin impressions that we would have never seen (or moulded) had the footprints remained “dirty”.

As frustrating as the clay was to clean out of the skin impressions, it was very exciting to see: this type of clay forms from volcanic ash falling onto the footprints soon after they were made. This told us that the weather patterns were right for a volcanic ash layer to fall on northeastern British Columbia 72 - 74 million years ago. Perhaps our tyrannosaur actually saw the glow of the eruption? We’ll never know, but it is fun to imagine.

The track surface cleaning took a long time. In the meantime, Charles and Rich moved the research and moulding equipment to the site by easing the AVT down the hill. What goes down was not going back up: the hill was too steep for the ATV to make a return trip using that route, but we had planned for this: an alternate route was mapped out using Google Earth for our regress. Rich calculated where the third footprint in the series would be if it were preserved. If you know approximately how long of a step the trackmaker was taking, which we had from Footprint #1 and Footprint #2, you can figure out where Footprint #3 would be, even if it is still covered in rubble. Charles and Rich began excavating at the base of the hill to search for the third footprint, and successfully uncovered it!

The first tyrannosaur trackway. a) The second footprint in the trackway. b) The exposed trackway. You can see, way at the end of the trackway, the pale clay layer that we had to clean out of the footprints. Modified from Figure 2 of McCrea et al. (2014).
While Tammy and I began the detail cleaning of Footprint #3, Rich got to work documenting the exposed trackway. This is when he noticed something odd about this trackway. The Footprint #1 made by the left foot, was a little damaged by weathering. The inner toe (digit II) was not completely preserved: it seemed too short. Footprint #2, from the tyrannosaur’s right foot, was uncovered by Mr. Fredlund, and all of the toes were beautifully preserved. When we finished cleaning out Footprint #3, made again by the left foot of the tyrannosaur, we saw that digit II was too short on this footprint. This was not damage due to weathering: this animal was missing the end of its inner toe! This is called a pathological footprint: check out McCrea et al. (2015) for a detailed description of injuries seen in dinosaur footprints.

Figure 7 of McCrea et al. (2014), photogrammetric rendering of the first tyrannosaur trackway. You can see the consistently missing digit II impression. I might call this specimen "Stumpy".

Charles had to leave the site around 3pm. That was when we were finally ready to start the silicone mould. Silicone is easy to mix by hand in small quantities at room temperature. However, I had to mix large batches at around 5C. Silicone is very, very stiff when it’s cold: it’s like trying to stir molasses or all-natural peanut butter that has been sitting in the fridge. Silicone also doesn’t set properly if the catalyst and reagent aren’t thoroughly mixed: it just stays a gloopy, slimy mess.

There is another drawback to late year fieldwork: the lack of daylight. The light and temperature started to drop as I stirred, and stirred, and stirred. Each batch took about half an hour to properly mix, and then another half an hour to pour. By the time we had mixed and poured four batches of silicone, and had set up the heating tent over the silicone peel, it was 6:30pm and dark. Ice had started to form on standing pools of water. Our breath frosted in the air. It was going to be a cold, clear evening.

This is when we discovered just how rushed we were when packing our personal field gear. We had food, guide tarps, GPS, satellite phone, and warm(ish) clothing, but we had forgotten one crucial piece: The Flashlight. We weren’t initially concerned: Rich had mapped out a seismic cut line that we could use with the ATV (which has headlights) to get back to the field vehicle. It was a slow, bone-jarring trip through the dark wilderness, but we reached the opening to the cutline. We were home free...

...or not. Between Google Maps taking the images of this route and our escape (about two years), a beaver had made a dam, turning what would have been a steep but manageable slope into a large pond abutting a steep grade. There was no way to drive around the pond. After expressing a few non-printable words towards beavers and all of their kin, and finding out that similar access points were also cut off, we made our slow creeping way back to the track site.

Bwaahaahaa! Image link.
We returned to the site around 11:30pm. After checking that the heating system for the silicone peel was still working, we surveyed our possible lighting resources. GPS screens emit light, but not enough light to hike through the woods. Makeshift torches of burlap do not work unless you can soak the ends in pitch. We had gasoline, but that burned too quickly for a consistent light source. None of the screens on our 2011 flip phones gave enough light to safely hike by (this was before phones with flashlight apps). The Moon was not full enough to hike by, and our trail was treacherous even in full daylight. We had no choice: we were stuck for the night at the track site.

I called Charles on the satellite phone to let him know our situation. The phone made an unstable connection, and all I could get out was “Hi Charles, we’re OK, but stuck at the site for the night...” when the connection broke. Satellite phones are great for remote field work, but at that particular time our satellite coverage was poor, and we were in a canyon. What I had wanted to tell Charles was that we were stuck for the night, but could wait until dawn to make our way back to the truck.

We assessed our emergency camping options. We set up our first camp on an open patch of ground, with our backs to the ATV and facing a nice fire. We used our backpacks in place of a ground pad, and huddled under the guide tarp. We were fine here until the winds shifted direction. The ground cooled and sucked the warmth right out of us. We then moved our makeshift camp into the shelter of the woods. While Rich cleared a safe area for a fire, Tammy and I built a huge pile of dried leaves. Once the fire was going we burrowed into the leaf pile and pulled the guide tarp over us.

I actually fell asleep. I can sleep in just about any situation, and after the long day and finally being warm and comfortable, I slept like one of the rotten logs on the ground next to us. All of a sudden my lovely sleep was interrupted by loud crashing down the hill and shouting. It was an unexpected rescue party! When I had called Charles, he interpreted the call as a “please come rescue us” call. After letting people in town know we were safe, he, Thomas Clarke, and Pearl the Helm Dog hiked along that horrendous trail in the dead of night to bring us home. They reached our campsite around 3:30am.

My first emotion? I will admit that it was annoyance at having been woken up (this will be the first time Charles will hear this confession). I was prepared to sleep for another couple of hours. Part of my brain wanted me to grumble “Go away!” I was the only one thinking that: Tammy admitted to feeling quite chilled and uncomfortable. We extinguished our fire, packed up our gear, and followed the lights of our rescuers back to the truck.

There, sitting on the front seat to add insult to injury, was a flashlight that had fallen out of one of our backpacks.

Every field bag and field jacket that I own now sports this teeny little flashlight. Lesson learned.
This trackway was well worth the unexpected overnight camping trip. Later visits to the site in 2012 and 2013 gave us time to clear off more of the track surface, revealing two more tyrannosaur trackways. All three trackways were walking at a leisurely pace (between 6.4 and 8.5 km/h) in the same direction and were spaced evenly apart (about 3 m). We were also able to figure out approximately how old the track-makers’ were when they made their journey from present-day British Columbia to Alberta: the track-makers were between 25 and 29 years old. This may sound young to us, but this is close to the upper age range known for Albertosaurus sarcophagus (Erikson et al. 2010). 

Figure 3 of McCrea et al. (2014). I'm working on cleaning out one of three trackways, and cursing at clay.
This site told us several things: 1) that tyrannosaurs spent time in northeastern British Columbia, 2) how tyrannosaurs walked and moved their feet when they walked, and 3) that adult tyrannosaurs, despite evidence of antagonistic behavior (e.g. fighting and face-biting, Tanke and Currie 1998) did spend time in each other’s company. This track site is also good evidence of group behavior in tyrannosaurs. There were hints before of tyrannosaur group behavior. Currie and Eberth (2010) suggested this from the tyrannosaur bonebed in Alberta, but bodies and bones can be moved after the animals die and deposited in a pile: in situ footprints cannot.


This site has great potential for further excavation: all three tyrannosaur trackways head into the hill. Unfortunately that hill is very high and steep, so any future work will require a lot of resources to move the mountainous amount of silt, sandstone, and mud from over the track surface. We cannot safely tunnel into the hill to expose more tracks: that seems like a plan riddled with Wile E. Coyote kinds of danger. 


Hopefully this tale of working on the terror of tyrannosaurs - and a fairly epic field work fail - will amuse and entertain until I can get to the Early Cretaceous track site work we did this summer. Stay tuned!

References:

Currie PJ, Eberth DA (2010) On gregarious behavior in Albertosaurus. Can J Earth Sci 47: 1277–1289. doi: 10.1139/e10-072  

Erickson GM, Currie PJ, Inouye BD, Winn AA (2010) A revised life table and survivorship curve for Albertosaurus sarcophagus based on the Dry Island mass death assemblage. Can J Earth Sci 47: 1269–1275. doi: 10.1139/e10-051 



McCrea RT, Tanke DH, Buckley LG, Lockley MG, Farlow JO, Xing L, Matthews NA, Helm CW, Pemberton SG (2015) Vertebrate ichnopathology: pathologies inferred from dinosaur tracks and trackways from the Mesozoic. Ichnos 22(3-4):235-260.


Tanke DH, Currie PH (1998) Head-biting behavior in theropod dinosaurs: paleopathological evidence. Gaia 15: 167–184.

Saturday, August 29, 2015

Fieldwork Flail -The Ups and Downs of Being Out and About

Hello, Dear Readers!

Well, the thesis is off to the committee (eep!), so now I get to digitally dust off the blog and leave the academic hermitage that is writing thesis chapters! I've been figuratively chained to the office for most of the summer. While this was a self-imposed office banishment, having to stay indoors and write during the summer when every fiber of my being was screaming to be outdoors doing fieldwork wore on me. Needless to say, once the writing was done, I jumped at the opportunity to visit one of my favorite neoichnology sites before all the shorebirds abandoned us to the cold weather (thanks, birds). The site is a couple of hours drive from the museum and great for (long) day trip fieldwork.

What follows is a mixed bag of success and frustration: in short, it's the typical field story. 

I arranged with our summer field tech, Linda, to pick her up at 6am. I went to bed early, as I'd be up before the sun to put the finishing touches on my neoichnology field gear. Thanks to some horrid reaction to something I ate, I did not get to sleep until 2am. As I finally drifted off to sleep I thought "Oh, this trip is starting out well..."

The alarm blares off at 5am. I will be honest with you: I am not a morning person, even when I've had a decent night's sleep. "Good" is not paired with "morning" in my vocabulary. Our museum staff (morning people, the whole lot of them) take great delight in being all chipper around me when I first enter the building. The walking dead have more life in them than I do on waking. Several cups of tea infused me with what passes as life, I picked up Linda, we loaded the last of the gear into the field truck, and left town for a pleasantly uneventful drive to the site.

Oh, sorry. I slipped into telling fiction. Back to reality.

We were driving down the highway, which is pleasantly empty at this time of the morning. This means that I'm not ticking off the drivers who want to do 100-120km/hr by driving the speed limit (90km/hr). Given the driving habits of the region and the fact that we are smack dab in the middle of the BC wilderness, there are a lot of black tire marks on the highway. I didn't think anything of that new black mark on the road...until I was close enough to see that it had thickness. I slowed and swerved around whatever it was...

BANG!

My foot left the gas immediately. We slowed to a crawl. This let me know that a) my tire(s) were still attached to the truck, and b) the axles (if damaged) would last long enough to get us to a safe shoulder. We crept along the road until we found a turn-off to a gravel road, engaged the hazards, and stepped out to survey the damage.

The flattest of all tires.

Important Field Tip #1: Know how to change the tires on your field vehicle. Don't just assume that you know how to change a tire - actually practice on your field vehicle before you set off on your adventures. Everyone on your field crew needs to practice being the lead on changing a tire. Even though we were right on the highway, we had no cell service and the satellite phone was being twitchy, so there would be no calling BCAA.

Fortunately for me and Linda, while we had not been the leads on changing a tire, we knew enough from several assists how to do it. The most troublesome part of the process was lowering the bloody spare from under the vehicle because we couldn't find the thrice-damned attachment for the jack that fits into the decent mechanism. Which leads me to...

Important Field Tip #2: Keep all of your jack attachments in one area, even if they are small. It took longer than it should have to locate the proper attachment, which was helpfully located in the glove compartment. Once located, we were off to the races, so to speak. During the process we also encountered...

Important Field Tip #3: People are jerks. Don't trust that they will bother to stop, slow down, or even move their vehicle as they roar past you at 110km/hr on a relatively narrow highway. Out of the seven vehicles that drove past, not one even slowed down. This was all well and good - we didn't need help (and we didn't want the hassle of trying to tell someone that the damsels in distress actually could change a tire all by our little selves), but the gravel and dust being whipped at us from speeding trucks got old.

The tire change went smoothly. Once the tire was off...
we could see the extent of the damage. Whatever the tire had hit, it went right through. There would be no patching this tire. That tire wasn't just damaged: it was cancelled.
Linda shows us the extent of the damage.
That was Adventure #1. We decided that we deserved to stop at Tim Horton's before continuing on to the site. We also made a note of our location, because on the way back we planned to find the wretched thing in the road that thrashed the tire.

We made it to the parking area of the field site without any incident. Accessing the neoichnology site requires crossing a river. Usually the river is gentle and shallow enough at this location to cross without too much difficulty. However, recent rains had given the river a bit of vigor and depth. Each of us had a cumbersome load to pack across the river (plaster, mixing buckets, cameras, personal gear), and the local river bed flora add a nice element of slime to the bouldery river bed. Crossing would prove to be tricky.

We found a spot that looked promising, and started across. A combination of bulky gear, slimy boulders, and a slight misstep sent me flailing into the river.

SPLASH!

All I remember going in was thinking "S**t, the camera!" and holding that aloft with my right hand while my left hand let go of the bucket (which Linda retrieved before it floated off on its own adventure) and broke my fall. This area was deep enough that I didn't break my fall before going almost completely under the water - I think the top of my head was still dry - but the palm of my left hand took the full force of my fall as it hit boulders and gravel. Needless to say, there was a little bit of damage.
It's only a flesh wound...I hope.
I carry a first aid kit with me, but there was very little I could do at this point that couldn't wait until I reached civilization. Sure, I could have dug around in my hand to remove bits of embedded gravel, but nice cushiony blisters formed around the impact sites, so I knew where the offending material was located. What worried me more was the sharp ache deep in my first metacarpal - did I break or crack it? I could still move it, albeit with some discomfort, so I figured we had come too far to give up on the chance of shorebird traces.

We finally crossed the river, and I changed into more-or-less dry clothes. We had arrived!

This area is dominated by Canada Goose tracks, and the fine-grained sediment captured their trampling nicely.
Canada Goose trample surface.
With the Canada Goose tracks were smaller anseriform (duck) footprints: they have a different overall shape than Canada Goose tracks, so we knew they weren't young geese.

Duck, duck, (not) goose. Do you see the inward curving outer toes?
Did you see the webbing? Webbing is a useful feature when it preserves, but webbing is inconsistently preserved in bird tracks. If the sediment consistency is just right (firm yet damp, like a firm wet beach sand), webbing may not impress. A more reliable feature is the curvature of the lateral toes: members of the duck group (Anseriformes) with palmate webbing (a completely webbed three-toed foot) have digits II and IV (the outer two toes) that curve towards the middle digit (digit III). Sandpipers with semipalmate webbing (webbing that attaches only partly down the length of the toes) do not have inward curving side toes.

Part of neoichnology is hanging out in an area long enough to see the local wildlife. Ideally, you want to see the animal in question make the footprints. If that isn't an option, you need to know who is frequenting the area. If the tracks you are looking at are fresh, there's a better chance that the trackmakers you see are the owners of those footprints. These tracks were relatively fresh, so I knew that there was a good chance the trackmaker was either nearby or would revisit the site. All we had to do was wait.

While we were waiting, we checked out the track surface for more examples of the same type of footprint preserved in different ways. Here is a great example of how there is not one preservational scenario that will preserve all features all the time.
The webbing on these Canada Goose prints is very poorly preserved, but the hallux (digit I) on the left footprint is gorgeous! Digit I is another one of those birdy features that is inconsistently preserved, yet so many rely on the presence of the hallux impression as THE feature for saying with 100% certainty "Yes! We have a bird print!" I have a paper in press that discusses how the fossil and neoichnology data shows it's rarely that simple. Stay tuned!

We also found great samples of skin impressions for Canada Goose footprints. This print doesn't look like much at first glance - no webbing, no hallux, no "heel" pad (which isn't really a heel, but a fleshy pad where the toes and the end of the metatarsals connect)...
...but on closer inspection, it has great skin impressions!
A close-up look at the footprint shows that it preserves the creases, ridges, and pebbly texture on the bottom (plantar surface) of this Canada Goose's foot.

We also found evidence of our mammalian friends on the track surface: guess who?
If you guessed wolf, you would be correct!
Grey Wolf trackway overprinting the multiple trackways of Canada Goose. Bonus question: was this wolf walking or moving faster than a walk?
While we waited for the arrival of our small ducks (we could hear some quacking in the distance) we made a few plaster of Paris replicas of the different preservational variations of the Canada Goose and the as-of-yet unidentified small duck tracks.
Small duck trackway being cast.

The track surface with plaster replicas (white patches) drying.
Making replicas of modern tracks is a really simple process, and it's something that anyone of any age can do. We use a fiberglass-reinforced plaster of Paris (Hydrocal FGR-95). I also add additional fiberglass matting to the backs of the replicas, as many of my track casts are long and thin. Field neoichnology casting is a cumbersome process: you have to haul out plaster, mixing containers, fiberglass mat (or chop, but that's a pain in the butt to work with) and garbage bags. You also have to haul the awkwardly-shaped plaster casts out of the field. However, I think it's worth it for bird tracks. We're getting mixed results with digital photogrammetry on small bird footprints, and one of the reasons is that they are often wet, shiny, and partially underwater. All of this extra reflection confuses the computer program, which "prefers" even, consistent lighting for all of the images used in making the 3D digital replica. Also, plaster replicas are cheap to make, and I'm an ichnologist on a very strict budget.

This brings me to Important Field Tip #4: Pack it in, pack it out. We mix all of the plaster in a container placed inside a garbage bag, and any plaster drips and slops are collected after they harden. We don't want to leave a trace while we collect traces.

While we were waiting for the replicas to dry, we saw that our small ducks had arrived!
This is a horrid picture, but viewing these ducks through my binoculars let me know that they are Green-winged Teals in their non-breeding plumage. They are a small brown dappled duck, but one was kind enough to rearrange its wing feathers long enough to show me the green patch.

This was a good day for ducks, but where were my shorebirds? We scanned every centimeter of this shoreline, crossed over this waste-deep body of water to a second projection of land and scoured that for shorebird prints, and came up with almost nothing. We saw really faint impressions of Spotted Sandpiper footprints, but they were made in such wet mud that they had all but collapsed in on themselves, leaving nothing but faint lines where the toes impressions should be. We were about to call ourselves skunked in the shorebird category when we came across this:
FINALLY!
It turns out there were a pair of Spotted Sandpipers at this locality, but they were being extremely sneaky with us. We turned every corner just to see them flying away: none were comfortable with us in their territory, and they were more or less avoiding walking in areas that would keep an impression of a footprint for more than a few minutes. This was a huge change from last year, when two Spotted Sandpipers took a short nap while I was taking photos of them. On our way back to the field truck at the end of the day, we found out the little buggers had doubled back on us and were foraging in the areas we had already prospected. This brings me to my final Important Field Tip: you can't control your wild study taxa. Some days they cooperate, while on other days they flip you the feathery Bird.


This was a typical field excursion, full of wins (great duck and goose tracks) and fails (the Thrashing of the Tire and my new gravel piercings). Regardless of the frustrating parts, it was great to be back in the field!

Until next time,
SW

P.S. - My thumb turned out not to be broken (yay!) but it was swollen and sore for a few days. Here is a picture the day after I landed on it. Luckily the blisters were just impact blisters - there were no embedded gravel chunks to remove.