Wednesday, June 30, 2010
After a couple hours, an errant stick in the spokes ripped off Dan's rear derailleur. This happened about a quarter mile from where this same derailleur was ripped off exactly a week ago. Poor Dan. More walking for him.
On the plus side, I got a few good shots of me riding out of the deal, which is rare.
Tuesday, June 29, 2010
In press at Geophysical Research Letters:
Kurt A. Refsnider and Gifford H. Miller
Evidence for the evolution of Laurentide Ice Sheet (LIS) basal thermal regime patterns during successive glaciations is poorly preserved in the geologic record. Here we explore a new approach to constrain the distribution of cold-based ice across central Baffin Island in the eastern Canadian Arctic over many glacial-interglacial cycles by combining till geochemistry and cosmogenic radionuclide (CRN) data. Parts of the landscaped with geomorphic evidence for limited glacial erosion are covered by till characterized by high chemical index of alteration (CIA) values and CRN concentrations requiring complicated burial-exposure histories. Till from regions scoured by glacial erosion have CIA values indistinguishable from local bedrock and CRN concentrations that can be explained by simple exposure following deglaciation. CRN modeling results based on these constraints suggest that the weathered tills were deposited by 1.9 to 1.2 Ma, and by that time the fiorded Baffin Island coastline must have developed close to its modern configuration as piracy of ice flow by the most efficient fiord systems resulted in a major shift in the basal thermal regime across the northeastern LIS. The resultant concentration of ice flow in fewer outlet systems may help explain the cause of the mid-Pleistocene transition from 41- to 100-kyr glacial cycles.
DRAMATIC INCREASE IN LATE CENOZOIC ALPINE EROSION RATES RECORDED BY CAVE SEDIMENT IN THE SOUTHERN ROCKY MOUNTAINS
Kurt A. Refsnider
Apparent increases in sedimentation rates during the past 5 Ma have been inferred at sites around the globe to document increased terrestrial erosion rates, but direct erosion rate records spanning this period are sparse. Modern and paleo-erosion rates for a small alpine catchment (3,108 m above sea level) in the Southern Rocky Mountains are measured using the cosmogenic radionuclides (CRNs) 10Be and 26Al in cave sediment, bedrock on the overlying landscape surface, and coarse bedload in a modern fluvial drainage. The unique setting of the Marble Mountain cave system allows the inherited erosion rates to be interpreted as basin-averaged erosion rates, resulting in the first CRN-based erosion rate record from the Rocky Mountains spanning 5 Myr. Pliocene erosion rates, derived from the oldest cave sample (4.9 ± 0.4 Ma), for the landscape above the cave are 4.9 ± 1.1 m Myr-1. Mid-Pleistocene erosion rates are nearly an order of magnitude higher (33.1 ± 2.7 to 41.3 ± 3.9 m Myr-1), and modern erosion rates are similar; due to the effects of snow shielding, these erosion rate estimates are likely higher than actual rates by 10-15%. The most likely explanation for this dramatic increase in erosion rates, which likely occurred shortly before 1.2 Ma, is an increase in the effectiveness of periglacial weathering processes at high elevations related to a cooler and wetter climate during the Pleistocene, providing support for the hypothesis that changes in late Cenozoic climate are responsible for increased continental erosion.
Monday, June 28, 2010
Friday, June 25, 2010
Always carry a spare derailleur hanger, or you too could descent South St. Vrain chainless and then get pushed/pulled along the Peak to Peak Highway like Dan did. Entertaining times on the Redstone Tuesday night [day-after-the-solstice] ride.
Tonight I'm heading out for a quick bikepacking trip over to Winter Park. My heart will definitely be more than a little heavy after hearing the news yesterday that Dave Blumenthal passed away after his run-in with a pickup truck on the Tour Divide course. It's a tough time for everyone in this tight-knit community. You just never know when you might not come back from your next adventure. Be safe out there, everyone, but at the same time, make sure you're doing everything you can to enjoy the world around you.
Thursday, June 24, 2010
Here are some examples of what mine road mayhem entails...
Monday, June 21, 2010
For the past 6 months, I've been running with this race particularly in mind. Strangely, it was my primary goal for this year because of the huge challenge I knew I'd be facing when race day finally arrived. I ended up running the 50-miler in Fruita in April just to make sure I could at least cover that distance, even though that was a considerably easier course. After Fruita, injury and racing the Arizona Trail on the mountain bike kept me away from running for almost month straight, but I came back with a focused 3-week block of some solid training in the mountains, running/hiking what turned out to be the probably the best possible training for San Juan.
All this paid off, and I finished the race this past Saturday almost an hour faster than my ambitious goal, and despite the course being even tougher than I anticipated, I was still having fun 25-30 miles, running along the Colorado Trail at close to 13,000'. On the first climb, I found myself in the company of some veterans who were all shooting for a sub-12-hour finish (my goal was 12.5 hours), and these guys were quite excited with how quickly we were to the top. I hoped to keep these guys in sight until the end.
Following Gilles in the early-morning sun
The second climb up to the continental divide was almost entirely hiking for all but the strongest runners. Half way up, we popped out of the woods at the third aid station and could see runners, far, far above us on the ridgeline. But the top was in sight, and as we eventually crested the ridge, the San Juan Mountains stretched out all around us in the clearest possible air. The weather was perfect, views to die for, and we had already climbed close to 10,000', meaning the worst was behind us. Sort of.
The final 2,000' climb through beautiful aspen groves and meadows was pretty brutal, making my hamstrings scream with every step. They were approaching the point where they could barely put out enough power to lift my body up the steep slope, but within an hour of leaving the aid station at 40 miles, we were at the top and beginning to descent gradually. Some clumsy math calculations led me to conclude that we simply had to cover 8 miles at 20 min/mile to finish in under 12 hours. Doug really loved this part of the course, despite the pain of 45 miles in the legs. I agree that it was pretty beautiful, but I would have enjoyed under different circumstances. My head was unfortunately more focused on my sore, wet feet, tired leg muscles, and trying to not roll an ankle on the many rocks.
"Yaaarrgh!" Doug exclaimed a while later as we were winding through some soggy meadows. Then he sped up!
"What?" I replied after a few seconds. "Oh! Yeah!" I saw some Jeeps and ATVs through the trees. The final aid station at 47 miles! That meant we only had an incredibly steep 2.5 mile descent back to town. I stopped, drank a couple cups of Coke, disappointed the awesome volunteers that I couldn't eat any of their food, and ran off after Doug. The volunteers cheered us on heartily, and we soon began the plunge back into the valley. Before too long, glimpses of houses and streets below filtered through the trees as we pounded our way down the rocky track.
Entering town, we could see a runner and pacer up ahead, and after a few blocks, another runner and pacer emerged from the woods behind us. Doug wasn't going to get passed without a fight, so he slowly pulled away from me, and the runner behind passed me in an impressive charge, dropping his pacer in the process. I had no fight in me, and my glutes were on the verge of cramping, so I plodded in, finishing just shy of 11 hours and 36 minutes. Looking back, I can't see where I could have taken off more than a total of a minute or two, which means I ran as well as I could possibly have hoped. I'm pretty proud of that. I also managed 3rd in my age class and 37th overall to boot, both of which were very unexpected.
Not bad for a mountain biker, eh?
Thursday, June 17, 2010
Well, I've got my own challenge. I came across this race 8 months ago when I started running. It's only a single-day event. Actually, I hope to finish it in under 13 hours (which'll be a tough goal to meet). Yet, I'm surprisingly apprehensive about this thing. Perhaps the course profile is to blame.
For those of you familiar with the Colorado Trail, the second tall hump on the profile is the Coney Summit section. It's high, rugged, and exposed. However, the weather forecast looks ideal, and rumor has it that the course is free of snow and in the best condition in years. Let's see how it goes...will there be more running races after this one, or focus shift back to wheeled conveyances?
Monday, June 7, 2010
My alarm rudely played its truly awful tune and jolted me awake. The familiar feeling of disgust and disdain for that kind of morning greeting returned deep within my gut. Before my eyes opened, I felt a wave of cold flood across my body and realized that sometime during my 3-hour slumber, my muscles had succumbed to shivering. I opened my eyes. It was just as dark beyond my eyelids, but a few stars found their way through the forest canopy above. My tongue stuck to the roof of my mouth as it does most mornings on the trail from dehydration, and my lips were tender and peeling from too much sun and wind. As I sat up, still shivering, the soft pine needles crackled beneath me. It was a shame such a comfortable place to rest had to be so cold. And so short-lived. I quickly got out of my sleeping bag and bivy, pulled on my bike shorts and rain pants, switched into my stiff, stinky socks, and layered on everything I had for my torso. Waking up to cold temperatures always made me move quickly. There's no time to relish the relative warmth of the sleeping bag while eating a cinnamon bun, stretch stiff muscles, and look at the terrain that will be the morning's work. The goal instead is to get dressed, packed up, and moving in order to warm up. Breakfast, whatever that might be, would come on the move.
Standing up almost sent me straight back the ground. My knees ached and my quads were reluctant to stretch enough to stand up straight. Amazingly, my sore Achilles felt alright with the tape still supporting it. Within a few minutes, I was slowly rolling down the trail. It was a bit tough to follow in the groggy darkness. My legs felt completely empty, barely able to pedal their way up anything beyond a gradual incline. The thought of crossing the Grand Canyon seemed inane; reaching Tusayan was going to be a big enough challenge, and that was only 20 miles away. I tried to not let the early-morning difficulty weigh on my mind, but after how much I struggled to continue riding the prior evening, it was perfectly clear that my body was quickly reaching its breaking point.
During the previous evening, the descent from the San Francisco Peaks, bolstered by favorable winds, carried me out onto a desolate landscape. But a shift in both the winds and the route quickly turned the tables, and simple forward progress was my sole goal for a few hours. The winds gradually died as the sun set, but by then, the Arizona Trail left the friendly two-track and onto a loose, windy singletrack that meandered up and down, somehow putting me to sleep in the process. My legs weren't able to pedal hard enough to keep my mind entertained with the challenge of the trail. A hard crash knocked the wind out of me as my front tire washed out in an unexpectedly loose turn, but even that failed to jolt my brain back to a state of alertness. I was forced to stop a couple hours after dusk and nap for ten minutes. For three more hours, my mind and legs were at odds, and I eventually had to give in to the urge to stop high on the Coconino Rim. Picking up where I had left off the night before, life was not feeling any easier. Six days of hard riding and minimal sleep had just about brought me to my knees.
Even at the lowest points in these endeavors, the trail gods always seem to have an unexpected gift hidden away, ready for release at the most critical moments. It might be a lone elk galloping across a barren plain, sending up a plume of dust in front of the setting sun. Often it is a short, exhilarating descent to get the heart rate up and force the mind to focus. Last year on the Kokopelli Trail, this gift came in the form of a soaring meteor, extinguishing itself in a burst of light that was the highlight of an otherwise dismal ride. On this particular morning, it was as simple as a brilliant orange sunrise, stretching out in front of the still-dark Coconino Rim. I stopped briefly to admire the spectrum of color, from hues of red-orange through yellows and blues to black, all in just a thin band above the plateau in the distance. This gradually began to illuminate the trail, and as it did, my speed increased slightly, a rhythm began to work its way into my legs, and most importantly, the 20 miles to Tusayan seemed a little more reasonable. I reached up above my helmet and clicked my light off. A new day had begun yet again. In the back of my mind, I knew entirely well that it was still going to be a monumental struggle, but I also knew that I'd be eating watermelon at the Utah border the following afternoon.
Sunday, June 6, 2010
Atop the first pass, the grey and black skeletons of long-ago burned cedars stood silently as I passed. The trail wasn't quite above treeline here, but it certainly felt like it. From this vista, I surveyed the this little part of the world from a new vantage point. To the northwest across South Park, among the snowcovered peaks of the Mosquito Range, I picked out Mount Tweto (named after a geologist!), which I hiked up a few years ago. Mount Guyot, the highest point on the Firecracker 50 course, stood just to the east. Farther south along the horizon, I admired the Collegiate Peaks and some of the 14ers we climbed last weekend. Farther south yet were the last snow-capped peaks standing just above the wonderful Cochetopa Hills. I traced the Tour Divide course from Boreas Pass into and across South Park, as well as another of last summer's rides through the park and over the Puma Hills, which stood just below me to the south. Recently I've had the feeling that I haven't been exploring all these mountains in my back yard as much as I should be, but this vista provided some satisfying reassurance.
Eventually the trail climbed above treeline, almost to 12,000', and I kept running. My legs were still feeling great, probably fueled a bit by the continuing remarkable views. But as I reached the northern end of the ridgeline, I veered west and descended steeply back down into the forest. The last 15 miles of the run were less scenic and inspiring, but I plodded along, slowly put the miles behind me and made it back to the car in 10 very satisfying hours. I have a feeling I'll be back to run this exact loop again...
The need for an easier run today provided the chance to explore a new (to us) trail a little closer to home. The trailhead parking lot was packed, but the trail was relatively deserted and delightfully scenic. Throw in an abundance of rocks and gruss and my mind was distracted enough to not feel too many of yesterday's miles.
Now the San Juan Solstice is just two weeks away, so it's time to back off, let the legs recover fully, and make the most of all the hard-earned miles pounded out over the past few weeks.