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On the Subject of Dust

Vanishing Tropical Glaciers - Mon, 07/25/2011 - 03:29

20th July – Dispatch from Nevado Ampato, Andes

Our camp is at 5045 m on the dusty slopes of Ampato, an extinct, ice-clad volcano in the Western Cordillera. This is the very mountain from which Juanita, the famous Incan ‘ice maiden’, was plucked back in 1995. The tents are clustered in the lee of a large glacial erratic and, now the clouds have cleared, the view is second to none, taking in the dry plains far below and myriad volcanic peaks in every direction. Of these, only distant Ubinas shows any activity, letting slip the occasional cloud of ash. To complete the picture, behind us are the hulking masses of 6380 m-high Ampato and it’s smaller yet more violent brother, Sabancaya.

Windy campsite below Ampato and Sabancaya

Yes, it is a fine place to call home as we begin mapping and sampling moraines of late-glacial and Holocene age in this part of the world. For added interest, the landscape here is dominated by sinuous lava flows that extend many kilometres from Sabancaya’s summit to the puna below. These black tongues of rock are both grotesque and strangely beautiful, especially when dusted with snow.

Kurt Rademeker high on the slopes of Ampato

Speaking of dust, or rather sand, recently it has become a bit of a plague. Given the propensity for volcanic activity in this part of the Andes, our peaks camp is located on a surface of black sand, dust, and gravel, much of which becomes airborne during the fierce wind storms we’ve been experiencing. Just yesterday, as we were working on the youngest and highest moraines on Ampato, we happened to be suffering through a particularly bumpy spell of weather.The wind was funnelling down from the peak and pushing around waves of drifting snow. It was truly invigorating! From our high perch, though, we watched as plumes of dust were lifted by the wind from the plateau below, forming a brown blanket that came to obscure all but the highest peaks before spreading south to torment the city of Arequipa. By the time we returned to our camp that afternoon, our world was one of particulate matter. Sand in our food, sand in our tents, sleeping bags, and clothes. Worst of all, there was sand in my tea. But then, they always did say it takes a lot of grit to be a glacial geologist.

Gordon

Boring Days at Sea are a Blessing

Andy, Hannah and Mike in the main lab

For the last nine days, we have been underway acquiring seismic reflection data to study a plate tectonic boundary offshore Alaska with the R/V Marcus G. Langseth. Now that the initial excitement of deploying all of our seismic gear and watching the first sound waves arrive on our two 8-km-long streamers has faded, we have settled into a routine of watches and standard shipboard data processing. Meals, sleep and leisure also take on predictable patterns. Each day resembles the one before, and they all start to blend together. This may sound rather humdrum, but an uneventful day at sea is normally a successful and productive one (as one of the undergraduate watchstanders noted). When something “exciting” happens, it is usually not good.

Workboat returns from repairing seismic streamer

Happily, a large proportion of our nine days have been blissfully boring, but we have had our share of happenings. Excitement takes the form of equipment failures, bad weather and marine mammals. Acquiring marine seismic reflection data is a fantastically complex undertaking involving a lot of sophisticated, interdependent gear, so things can and do go wrong once in a while. A few nights ago, one of our streamers sank too deep, causing a “streamer recovery device” (a specialized airbag) to deploy and float the streamer to the surface. The next morning, a team used the workboat to visit the problematic streamer section and remove the airbag. On a few other occasions, I have received phone calls in the middle of the night summoning me from my cabin to the main lab to discuss other equipment hiccups – no one ever calls at 3 a.m. to let you know that everything is going swell.

Humpback observed from marine mammal observation tower on Langseth (picture courtesy of PSOs)

Whales are beautiful and majestic, and we have been treated to numerous sightings, but we try to keep our distance. Since we are creating sound waves to image the earth, and marine mammals use sound to navigate and communicate with one another, our activities might disturb them. A team of protected species observers (PSO) watches for mammals, and we suspend operations if a mammal comes too close. Yesterday morning, we found ourselves surrounded by three species of whales, including a rare Northern Pacific Right Whale – an amazing sight, but it prevented us from collecting data for nearly four hours.

Other "good" excitement: beautiful views. Castle rock by Chignik Bay.

Of course there are notable exceptions to the “excitement is bad” maxim, the most important of which is the science! We use our new data to create very preliminary images of the structures below the seafloor as we go, and they have revealed some intriguing and surprising features. A regular sight in the main lab is a group of people gathered around a computer screen or a large paper plot, talking and pointing excitedly. We have a lot of hard work ahead after the cruise to obtain concrete results, but it’s exhilarating to glimpse faults, sediments and other structures in our data for the first time and ponder what they might be telling us about this active plate tectonic boundary. Even after spending a total of nine months at sea on ten research cruises over my career, the excitement of new data has definitely not worn off.

Collecting Data Offshore Alaska, But Just Barely

Seismic gear towed off the port side coming very close to the Unga shore

One of the core objectives of our project is to image the part of the plate tectonic boundary that locks up and then ruptures to produce great earthquakes. In the Aleutian subduction zone, the Pacific plate is being thrust northwards underneath the North American plate. To examine deep parts of the interface between these plates, we need to go as far north (and as close to the coast) as possible. This is easier said than done. We are towing a lot of scientific equipment behind the ship, including two 8-km-long cables (streamers) filled with pressure sensors, so approaching the coast and making turns is complicated and requires special attention to safeguard our gear. The southern edge of the Alaska Peninsula is rugged and flanked by lots of small jagged islands and shallow features just below the surface of the ocean. Currents and water density can vary locally near the coast, which could affect the positions and depths of our streamers behind the ship. And there is more fishing activity close to the coast, and thus increased risk of tangling seismic gear with fishing lines and nets. To reduce the risk, we scouted all of the trickiest parts of our survey ahead of time before we deployed the streamers, and we monitor the currents and fishing as we approach the coast. Captain Jim O’Loughlin, Chief Science Officer Robert Steinhaus, and the Langseth’s other crew and technical staff have a tremendous amount of experience and skill in maneuvering in tight spots while towing seismic equipment.

Navigation screen showing the Langseth and her streamers (blue) approaching the Unga coastline (green)

We recently completed one of our closest approaches to land near Unga, one of the Shumagin islands. At the apex of the turn, our 8-km-long (5-mile-long) streamers came within less than a mile of the coast. Due to some early difficulties with our equipment and an abundance of marine mammals, we had to make several attempts to collect data on the landward part of the line (and thus several passes near the shoreline). I held my breath and watched our third (and final) pass from the bridge.  After the ship and gear passed safely through the most harrowing part of the turn, the captain turned to me and asked, “We’re not going to do this again, are we?” Thankfully not! At least not here. But there are several other important parts of our survey ahead that will require close approaches to the coast to image critical parts of the plate tectonic boundary. As with this near-shore encounter, we will rely on the skill and experience of the mates and the technical staff, as well as a little luck.

Going West

Vanishing Tropical Glaciers - Sun, 07/17/2011 - 15:21

14th July – Dispatch from Chivay, Peru

After a busy few weeks in the Cordillera Carabaya, we’ve said goodbye to the snowy, tempestuous climate of the eastern Andes and are moving west to the desert of Arequipa. Here the mountains are massive, isolated volcanoes, many of which exceed 6000 m in elevation. In fact, Coropuna is the third highest mountain in Peru and certainly the most sprawling. It’s a landscape dominated by lava and aridity, and populated only by wild vicuna, condors, and a few hardy llama herders. Our first stop was Chivay, a lovely little town nestled in the upper Colca Canyon under the shadow of the enormous Nevado Ampato. We spent a day there recharging, replenishing our stocks and generally avoiding the blizzard on the plateau above. This being the desert, we had not anticipated that the bad weather would follow us west, but evidently it is possible. There is nothing quite like driving through the night, down the side of a canyon, in a snowstorm to focus the mind!

Passing through a Peruvian desert town, heading west to Arequipa

Our work here involves mapping both the glacial deposits and Holocene lavas on the two volcanoes, Ampato and Sabancaya. Though in sight of Arequipa, the place is actually more remote than Coropuna, accessible only via a two-hour drive down a washed out dirt road. This is a new region for us and so it promises to be a fascinating few days of exploring.

Gordon

Unspooling Miles of Seismic Streamer Near the Shumagin Islands

Two reels of seismic streamer on the Langseth

On July 11, we marked the successful completion of the first phase of our project and embarked on the second.  Part 1 involved deploying ocean bottom seismometers and recording air-gun-generated sound waves. We successfully retrieved all of the OBS’s, and the data that they recorded look very exciting at first blush (and contain some surprises!).  Part 2 involves towing two 8-km-long cables (or streamers) filled with pressure sensors behind the R/V Langseth, which will also record sound waves from the Langseth’s airgun array.  Changing gears in terms of scientific activities also involved changes to our science party; we swapped personnel in Sand Point on a beautiful sunny evening. The excellent OBS team from Scripps departed on the Langseth‘s zodiak, and we were joined by new reinforcements. The newcomers included five undergraduate students from Columbia University, who are also blogging about their experiences at sea.

Columbia grad student Jiyao carries "bird" for seismic streamer

Just two hours after taking on our new personnel, we started deploying seismic gear – a very quick transition! Our seismic streamers are stored on gigantic spools, which unreel cable off the back of the ship into the ocean.  A large buoy is affixed to the end of the streamer, and ‘birds’ are attached along its length, which can be used to control the depth of the streamer. Large paravanes hold the streamers apart; these are like large kites flying in the water off the back corners of the ship.

Deploying miles of streamer and the other attending gear is an impressively long and complicated undertaking.  We started over two days ago, and have been working around the clock in shifts ever since.  Many repairs and adjustments are made to the gear as it’s deployed. The streamer is divided into 150-m-long sections connected by modules; both sections and modules can fail and need to be replaced. Replacing a 150-m-long section of cable is an arduous task involving major manual labor by teams of ~5-6 people. But we are nearing the finish line; as I write, the last kilometer of the second streamer is going over the back of the boat. Fingers crossed that the deployment will soon be complete and the data collecting can begin!

Seismic streamer with a "bird" being deployed into the ocean

Mad Dogs and Englishmen

Vanishing Tropical Glaciers - Mon, 07/11/2011 - 23:32

10th July – Dispatch from Nevado Tolqueri, Cordillera Carabaya, Andes

We have acquired a dog, ¨”Mooch”. Walking back to camp yesterday, amid driving snow and fully laden with rock samples, there he was exploring what passes for our kitchen. Unlike most Andean dogs –  ferocious beasts trained to keep geologists from harassing the livestock – this one is a cheerful soul, happy to hang around and be fed whatever is going, and always up for affection. Where he came from we don´t know. We´re camping at 4750 m in a shallow valley between moraines that keeps the worst of the wind at bay.

Mooch arrives in our camp, Cordillera Carabaya

There is nothing to burn here and so the nights are frigid, though the view of the entire Cordillera Carabaya, as far as Bolivia, is superb. There are a few hardy souls farming alpacas up here, so presumably the canine comes from one of those, but nobody seems to be missing him. Last night he cleaned our plates and pans, as the snow fell all around, and this morning he was still there. I awoke to find  Mooch curled up by the stoves, tucked up in a snowy ball. He immediately perked up once I arrived and waited with agreeable patience as we made a sort of rice pudding for breakfast. Then, with breakfast done, he followed Matt and me as we went off to collect a few more samples for surface-exposure dating. It will be sad to leave the pup, but we must head west soon to the desert Andes. And as Kurt noted, a high-altitude dog accustomed to sleep in the snow would hardly fare well in subtropical New York!

Happy campers in the eastern Andes

A word on the weather here. It´s taken a turn for the worse. We´ve been working on LGM moraines beneath Nevado Tolqueri and have made great strides there, collecting tens of samples from a fantastic sequence of moraines. But a drawn out storm has engulfed us from the east, appearing first as enormous thunder clouds and transitioning into incessant snow and high wind. It´s not quite what we´d expected but what can you do? It´s times like these we wish we had a kitchen tent instead of a patch of open mountain for cooking. It will be interesting to see how far west this system goes. In the meantime, we will try to keep our feet dry and the dog fed.

Gordon

Ancient mud from the high Andes

Vanishing Tropical Glaciers - Fri, 07/08/2011 - 12:22

4th July – Dispatch from the Andes
Thanks in large part to Matt, an undergraduate from Pacific Lutheran University in Washington, we now have more than sixty samples for surface-exposure dating. This is no easy feat, for collecting these samples requires a great deal of hammering on granite boulders with nothing more than a hammer and chisel. There are other ways of doing it, such as using small explosive charges, rock saws, or splitting wedges, but we find that good old-fashioned hammering is by far the safest way. I say ‘we’ but really this means Matt. He has a gift for removing large amounts of rock, be it a soft shale or the hardest quartzite. And best of all, he doesn´t complain. So in all, we have sixty four samples from the Aricoma region, from moraines of all ages. In addition to the hammering, the process includes detailed descriptions of each boulder and measurement of location, altitude, and how much of the surrounding sky is obscured by mountains. It can take a while but we have it down to an art now, as the ton or so of granite in the back of our vehicle attests!

Gordon sampling a sediment core from a bog

We´re also collecting sediment cores from bogs within the moraines, so as to provide radiocarbon ages for the deposits. Just yesterday we extracted a two-meter core from a basin near camp that lies between two long moraine ridges. It was a messy business, taking the three of us to punch the core barrel through the malodorous slime and into the stiff glacial clay, going as and as far as the rocks below. When all was said and done, each of us was fairly bloody and covered with ancient mud, but the core was extracted and the day was ours. Now the core is neatly contained in plastic tubing, sealed from the air and ready for shipment to Lamont where it will be analyzed.

Gordon

Summoning ocean bottom seismometers from the deep

Ernie reaches to tag an OBS

After leaving our seismometers on the seafloor offshore Alaska for a few days to record sound waves generated by the air guns of the R/V Langseth, we returned to collect them.  The recovery of OBS always involves a certain amount of suspense.  Despite all of the advanced engineering and planning that goes into these instruments, it is an endeavor with inherent risk, and things can and do go wrong sometimes: one or more of the glass balls that make the OBS float could implode; the acoustic communication with the instrument could fail; it might be stuck on the seafloor for one reason or another; it could have been accidentally dragged off by trawlers. All of these thoughts ran through my mind at each site as we waited for the instrument to come to the surface.

OBS returned with surprise stowaway: an octopus

To recover the OBS, we return to the place where we deployed it and communicate with it acoustically. We send it a command to release from its anchor and float back to the surface. The OBS rises through the water at 45 meters per minute, so the wait can be long if the water is deep. Some of ours were 5500 m below the surface! The instruments can also drift away from their original deployment location on the way down or the way back up due to ocean currents.  When they arrive at the surface, we can spot their orange flags and strobe lights; they also send out radio signals.

Despite all the technology required to place a seismometer many miles below the ocean on the seafloor and summon it back to the surface, many aspects of actually plucking an OBS out of the ocean and pulling it on deck are remarkably low tech (yet still very impressive).  Once we have spotted the OBS floating on the surface, the ship drives alongside. It is akin to driving your car up next to a ping-pong ball. People lean over the starboard side of the Langseth and attempt to attach a hook with rope to the bars on top of the OBS using a long pole. Its not always easy since the OBS is bobbing up and down in the waves. Once we hook it, we can attach a rope to the winch and haul the OBS onboard. Sometimes, OBS’s bring back surprises – an octopus returned with one of our OBS’s! He was alive and healthy, so we returned him to the sea (though some lobbied to keep him for lunch…)

Recording from an OBS. An earthquake (large event) overwhelms the regularly spaced pulses from our air guns.

Happily, we recovered 100% of our OBS’s and have started to (briefly!) pore over the data they recorded while they were on the seafloor. We can see the arrivals of sound waves from our air guns as well as lots of earthquakes, some very close and others far away.  It would be delightful to dig into the analysis of these data immediately, but it must wait – there is more data to collect! We’re currently deploying OBS’s along our second profile.

Deploying Ocean Bottom Seismometers off Alaska

Mark, Ron and Mladen deploy an OBS

On July 2, we finished deploying over twenty ocean-bottom seismometers as a part of our marine expedition to study a major tectonic boundary offshore Alaska. Ocean bottom seismometers (OBS’s) are autonomous instruments that sit on the seafloor and record sound waves traveling through the earth and the water. Floats made from glass balls and syntactic foam make each OBS buoyant, but an anchor holds it on the seafloor during the study. We communicate with each OBS acoustically, allowing us to send it a command to release from its anchor when we are ready to recover it.

For our project, we are placing OBS’s from Scripps Institution of Oceanography on the seafloor along two lines that span the major offshore fault zone.  Immediately prior to deployment, we assemble the main components of each OBS on deck while the ship transits between sites.  When we arrive at the deployment site, the ship slows down, and the OBS is lifted over the side of the vessel and into the water with a large crane. We release it, and it sinks to the sea floor. Thanks to the skill and hard work of the Scripps OBS team and the ship’s crew, we were able to deploy one OBS every hour, which is very efficient!

Rugged Alaska Peninsula seen from the sea

The larger the distance between the sound source (earthquakes or air guns) and the seismometer, the deeper into the earth the recorded sound waves travel. OBS are very sensitive and not attached to the vessel, so they can record sound waves generated very far away by earthquakes or air guns (commonly >200 km). Because we want to examine deep fault zones that cause large earthquakes off Alaska, OBS are a critical part of our effort.

In a few days, after we steam back over the OBS’s generating sound waves with our air guns, we will return to retrieve them. Even after ten years of working with ocean-bottom seismometers, it never ceases to amaze me that we can throw a bundle of very sophisticated electronics over the side of the ship and hope to pick it up and retrieve useful information from it. We are very excited about the new insights that will be provided by the data recorded on these instruments…

A typical day in the high Andes

Vanishing Tropical Glaciers - Sat, 07/02/2011 - 16:32

30th June
Each morning starts the same in the Andes: the frost is heavy on the insides of our tents and falls with the slightest movement, while the realization that it´s going to be a freezing exit from the sleeping bag is tempered by gratitude that the thirteen hour night is over. Yes, sunrise in the Andes is a momentous occasion each day, one that feels a million miles away from home. Kurt typically is the first up and dutifully begins brewing fine coffee on the camp stove. Matt emerges shortly thereafter. Nobody says a word, we just stand around in the frost like cold lizards – or maybe zombies – until the sun arrives to warm us. By midday it is fearsomely hot in the sun and the down clothing is replaced by sandals and wide-brimmed hats. Then, just as one is getting used to the idea of a nice afternoon siesta, the sun drops behind the skyline and the climate is icy once again.

Gordon and Matt mapping Holocene moraines above Veluyoccocha

One thing I am reminded of daily is that here in the Cordillera Carabaya, unlike in the western Andes, we are never alone. The moraines we investigate and the valleys we explore are someone´s backyard. Herds of alpacas swamp our campsite, followed by ferocious dogs, and mining trucks, laden with gold ore from Limbani, compete with our 4 x 4 for road space. We´ve met some interesting folk here, too, such as the toothless, Quechua-speaking alpaca herder high on a moraine, to school children asking us how to pronounce derogatory words in English.

We´ve been at Aricoma a week now and, I am pleased to report, have a lot to show for it. In addition to scratty, dusty beards and admirable tans, we´ve mapped and sampled glacial deposits young and old, from the last glacial maximum right up to the present day. This work has taken us up into the high valleys, where the last remnants of glacier ice are tucked away in shady recesses above 5000 m elevation. Here, we are surrounded by imposing peaks and deep, glacial lakes of indescribable beauty. It truly is a geologist´s dream, if a cold one.

Gordon

Heading to Sea off Alaska Aboard the R/V Langseth (at last)

View of Kodiak from the ship

Yesterday evening, we left Kodiak aboard the R/V Marcus G. Langseth and began our 38-day-long research cruise offshore Alaska. As we left port, we were treated to clear skies, calm seas and spectacular views of Kodiak – dark grey mountains tipped with snow emerging from the lush green landscape.

Although Kodiak offered beautiful sights and delicious seafood (like locally caught halibut and scallops), our science party was eager to leave for sea. We have been waiting for the opportunity to collect these data for a long time. Our expedition was originally planned for September 2010, but there were delays in the Langseth’s schedule that would have required us to conduct our offshore study later in the fall, when the weather deteriorates. Rough seas make some marine operations more dangerous and can also reduce the quality of the data. We opted to postpone until the summer of 2011 to secure a better part of the limited weather window in this remote and northerly region.

The R/V Langseth in port in Kodiak

But for some members of our science party, the wait has been much longer. In 2003, my colleagues Mladen Nedimović, Spahr Webb and the late, great John Diebold first conceived the idea for this study. Although many other scientists in our community and the National Science Foundation were very supportive of this project, it was scuppered by limited science funding and the temporary lack of a US academic seismic vessel between retiring the R/V Ewing and acquiring the R/V Langseth. But sometimes good things come to those who wait, and at long last we are setting out…

Foreigners in a Strange Land

Vanishing Tropical Glaciers - Sun, 06/26/2011 - 23:40

June 22, 2011

After a very cold morning in Crucero, the sun burned off the clouds to reveal the black peaks of the Cordillera Carabaya to the east. There´s not so much snow left on the hills these days, just a few glacier patches clinging to the south faces of the highest summits. Nonetheless, the vista is spectacular and Crucero by day is quite colourful, with fantastically painted buildings spaced around a busy plaza.

Stars over Laguna Aricoma

We had a stroke of luck today when we ran into a local man by the name of Demitrio. Demitrio was an enormous help back in 2009, helping us gain access to Aricoma and the hills beyond. This year he was all smiles and quickly ushered us into the mayor´s office, where Kurt explained (in his superior spanish) what we were doing and the objectives of our project. Now, with the town´s  blessing and a signed, official-looking letter in hand, we´re about to head off to our camp at 4600 m on the shore of Aricoma.

Gordon sawing plastic pipes on the roof of our hostel in Crucero

This morning we also made our final gear acquisitions – some plastic piping to transport sediment cores back to the US for analysis. These we had to cut into sections with a small hacksaw and then split in half, a delicate and quite tiring job at this altitude, but necessary. Now, vamos a trabajar!

Gordon

Finishing Up Onshore and Heading Offshore

Map showing the seismic stations we deployed onshore (red triangles) and planned offshore work

Seven days and eleven flights after we arrived in Alaska, we finished deploying our seismic stations onshore.  Our final constellation of stations differs a little from our original plan (as always happens with field work), but achieves our main goal of instrumenting the part of the Alaska Peninsula that is nearest to our planned offshore work on the R/V Langseth. We installed our final seismic station yesterday in aptly named Cold Bay. This town sits next to a large bay with the same name and is famous for its wind. The most common damages sustained by cars and trucks here are jack-knifed doors from the wind (as I learned the hard way!).

As luck would have it, we finished deploying our seismometers just in time to catch a large earthquake (magnitude 7.2) that occurred farther west in the Aleutians around the Fox Islands.  Of course we would love to immediately look at the recordings of this event on our stations, but we must wait patiently until August when we return to recover them. Many permanent seismic stations are telemetered, so data are transmitted back to scientists in near real time. But for temporary deployments like ours, the data are just written to a local disk and thus must be downloaded in person at the station.

I admire a small earthquake recorded at our Nelson Lagoon station

We did have the chance to take a sneak peak at some of the data recorded at our station in Nelson Lagoon during the first few days of our deployment.  Reassuringly, we saw evidence for several local earthquakes in these data, including a magnitude 3.1 near Sand Point.

Now that the onshore deployment is finished, Katie and Guy departed for home, and I soaked in some sunshine in Anchorage and started looking ahead to our upcoming research cruise.  Tonight I fly to Kodiak to await the arrival of the R/V Langseth and our shipboard science party…

Into Thin(ner) Air – On Route to the Cordillera Carabaya

Vanishing Tropical Glaciers - Thu, 06/23/2011 - 22:37

June 20, 2011

This morning we left Arequipa and the comforts of the tourist trail, driving east across the puna towards the Andes proper. Our route took us along the newly constructed Caraterra Interoceanica – a highway linking the Pacific coast of Peru to ports in Brazil – and up to elevations of 4700 m. Along the way we passed the smoking Volcan Ubinas, Peru’s most active volcano, and the enormous inland sea of Lake Titicaca. As we approached the Cordillera Carabaya, which bounds the puna to the east, the clouds increased and the landscape changed dramatically, from desert to grassland.

El Misti rising above the puna, en route to Aricoma

In recent weeks, social unrest related to the opening of a gold mine near the city of Puno has resulted in violent protests. Though we were able to avoid Puno as we travelled east, this sort of anti-mining sentiment underlines the importance of obtaining the blessing of locals to carry out our research on their land.

By mid afternoon we arrived in the small town of Crucero, located at 4100 m beneath Laguna Aricoma – our first site. This town is, frankly, a bit grim, consisting of grey concrete houses and rubble streets, and located on a windswept plain below the mountains. Nonetheless, we’ll spend the night here in order to meet with the governor tomorrow. Fingers crossed that he will remember us and grant us permission once again to roam around. To end on a light note, the Cordillera Carabaya happens to be the alpaca centre of the universe, and so there is a high chance that one of these cute fluffy camelids will end up on our dinner plates tonight.

Gordon

At the Feet of El Misti

Vanishing Tropical Glaciers - Wed, 06/22/2011 - 15:23

19th June 2011

What a difference a day makes! We’ve said goodbye to the sprawling metropolis of Lima and now are happily settled in Arequipa – the White City. This name refers to the white sillar rock used in the construction of the old colonial city and which is in fact a pyroclastic deposit from the volcanoes towering above us. From our hotel room I can see the massive bell-shaped peak of El Misti (5800 m), the only active volcano of the group, and it’s looking particularly snowy this year. In fact, flying in to Arequipa, I was surprised to see so much cloud. Normally, with this being the dry season, the sky in this desert region is blue and the mountains dry. Perhaps we should prepare for some wet, snowy field work!

Arequipa has grown on the flank of the active volcano, El Misti. The city center lies only 17 kilometer from the summit of El Misti. Much of the building stone for Arequipa, know as 'sillar', is quarried from the typical white pyroclastic flow deposits nearby.

Thankfully, nothing has changed at La Casa de Melgar, our Arequipa base, and I dug out my sampling tools from where I’d stashed them last year, a little dusty but in perfect working order. The rest of our gear, due to its incredible weight, is making its way slowly from Lima by road and should be here tomorrow morning. As for Matt, we found him in the airport, looking surprisingly fresh-faced after his red-eye flight, and so our field team is now complete.

Kurt and Matt arriving at Arequipa airport with Nevado Chachani behind

We’ll spend the rest of the day organizing our transport and, in the interests of science, sampling the rather incredible local cuisine.

Gordon

Installing Seismic Gear On The Beautiful (But Challenging) Alaska Peninsula

Katie and Guy install station in Port Heiden

Every field location comes with logistical hurdles, and the Alaska Peninsula is no exception. Weather, wildlife and modes of transport pose the greatest challenges. We are hardly the first scientists to encounter these: Lamont-Doherty Earth Observatory has a long, rich history of collecting seismic data in this region (e.g., Shumagin Seismic Network, which ran for >20 years), and many groups continue to collect geophysical data here today.

The Alaska Peninsula is too rugged and wild for a network of roads, so planes, helicopters or boats are the only transportation options.  We opted for planes, which immediately imposed a restriction on the locations of our seismic stations: they must be near airstrips. Happily, the Peninsula is sprinkled with small communities and lodges with airstrips, most of which lie close to the Pacific or Bering coasts rather than in the remote interior. Back in the office before our deployment, we chose the most ideally located airstrips for our stations and connected the dots between them with the most efficient possible flight plans.  But, our plans quickly changed once we were in the field. The weather dictates when and where you can fly each day, and it varies dramatically.  We have been lucky enough to have several clear days (even saw some blue skies and sunshine!), but other days we have been grounded by weather and wiled away the time indoors at the inn in Nelson Lagoon.

Scenic location for a seismic station

Once we arrive in each location, we need a quiet, safe place to install our equipment and a ride from the airstrip. On both counts, local communities have been unwaveringly helpful and friendly. The two school districts here kindly granted us permission to install our seismic stations at any of their schools, and we also obtained permission to place equipment at various lodges and village offices.  Residents volunteered to take our gear and us from the airstrip to our sites. In one town, our pilot made a general plea over the radio: “Is anyone listening on Channel 3? I’m here at the airstrip with scientists who need a ride to the school”. Someone answered immediately and picked us up 5 minutes later.

Fresh bear paw print near one station

Many of our sites are in spectacular places near remote lodges or in towns nestled between mountains and the ocean.  All of them are home to impressive wild life that poses a risk to our equipment, particularly bears.  We can protect the equipment against curious small animals but fully bear-proofing a station for a short  (two-month-long) deployment is not feasible. Instead, we hope that placing our stations in villages (rather than in the wild) will provide some protection, but we will also need good luck. Fingers crossed…

Off to Lima, World’s Second Largest Desert City

Vanishing Tropical Glaciers - Mon, 06/20/2011 - 23:29

18th June 2011  Lima, Peru

Our 2011 field season is underway. After a full day’s travel from New York, we arrived in Lima, the capital of Peru. This sprawling city perched on the edge of the Pacific Ocean is home to more than nine million people and, after Cairo, is the largest desert city in the world. Being winter in the Southern Hemisphere, the Peruvian coast is swamped by fog rolling in off the cold Humboldt Current and the sky over Lima is grey with smog and cloud. It’s surprisingly cool, too. Only the palm trees, cacti, and spectacular Spanish colonial architecture remind you that this is indeed the tropics.

Gordon outside the Instituto Geografico Nacional in Lima, Peru, holding freshly caught aerial photos in hand - an essential tool for the field work in the high Andes

Since our work will focus on detailed mapping and sampling of glacial deposits, we are heavily reliant on high-resolution aerial photographs of the field sites. Therefore, our first port of call this morning was the Instituto Geografico Nacional, a cartographer’s dream where enormous collections of maps and imagery are stored. It’s a spartan building with a distinct military air – a real throwback to more austere times – but the personnel there were very helpful, dutifully returning from store rooms with stacks of black and white photographs for us to peruse. Incidentally, these photos were taken in the 1960s by the United States Air Force and it never ceases to amaze me just how much the has retreated over the past 50 years. Some of the glaciers have vanished.

With that chore done, we’re currently packing (and repacking) our equipment for the next leg of our journey. Tomorrow we fly to Arequipa, Peru’s second city, located at 2300 m at the foot of the famous Volcan Misti. There we’ll meet up with Matt, who’s on his way from Tacoma as I write. Though we’ve been here only a few hours, it’ll be great to leave the coastal smog for the blue skies of the Andes.

Gordon

Switchyard Project: A Very Successful Year

May 22: The 2011 field season has been a very very successful year, in fact the most successful one we have ever had. The weather has been great, the equipment proved to be mostly reliable, the people have been great and the samples are plenty. In the month to come, we will analyze the water samples and eventually end up with a tremendous amount of very exciting data. Thanks to everyone who made this happen.

Area of operation and sampled stations in 2011 by LDEO (red "o" symbols) and UW (pink "+" symbols). Open white circles show the LDEO stations that we would like to target every year.

We left Alert yesterday and are on our way back home. We are stranded in Kangerlussuaq, Greenland, for a couple of days until the Air National Guard can take us and our valuable freight back to the U.S.

Best wishes.

The Switchyard Team.

Celebrating the end of the Antarctic field season

Using Rocks to Decode Antarctic Climate - Thu, 02/17/2011 - 22:18

We decide today is the last day for our camp, and we pack up and drive back to our base camp, the Central Transantarctic Mountain camp (CTAM). A sadness in a way, because it was our cozy home for a week. We ate, slept, and joked around here night after night. Also, we realize that packing up camp represents the end of the field season, except for one more day. For the last day of work we will fly by helicopter to the Achernar area from the CTAM camp.

Moraines at the Lewis Ice Tongue, the location of the last rock surface sampled during the field season

The last day at Mount Achernar. We use the helicopter to go near the southernmost part of the area, near the Lewis ice tongue, which comes off the East Antarctic ice sheet. After a long day, we collect our last samples, and wait for the helo to pick us up – the end of the field work for this season. We realize we had a very successful field season. Not one day of work was lost at either Mt Howe or Mt Achernar (a very rare experience for Antarctica). We think about how we accomplished our goals in terms of getting to both remote sites and collecting samples.

Spontaneous dance performance celebrating the end of the highly sucessful field season

Back at CTAM camp, we scramble to get all our stuff packed up ready to be shipped back to McMurdo. They are closing the CTAM camp for scientific work in a week because they need to take everything down by the middle of February. The middle of February represents the end of the field work for everyone in Antarctica. It starts to get too cold, and the sun starts setting in some areas farther north. People start to go home then and McMurdo gets ready for the winter.

The 'Antarctica's Secrets' team (Mike Roberts, Mike Kaplan, Nicole Bader, Kathy Licht, Tim Flood) getting ready to fly back to McMurdo station

We all fly back to McMurdo. A bed and running toilets (!) for the first time since we left for our camping trips. Also, the dorms have dark curtains that go over the windows. So, darkness, a bed, and a toilet – who would have known life can get so good!

Mike Kaplan (Lamont)

The Twin Otter, ready to fly the team back to McMurdo

Glacial deposits: A clue to reconstructing the history of the Antarctic ice sheet

Using Rocks to Decode Antarctic Climate - Thu, 02/10/2011 - 11:44

We set out on the snowmobiles with all the sleds to Mount Achernar with all our stuff. After about three hours we reach the site (crossing the flagged crevasse zone with no problem). We are joined by a fifth team member, Tim Flood, a Professor at St. Norbert College in Wisconsin. Tim has expertise in petrology or rock composition. So, we will have one additional person for the Achernar part of the trip.

Kathy Licht, Tim Flood and Nicole Bader exploring glacial deposits near Mt Achernar

At first we only find ‘blue ice’ to set up camp. Blue ice gets its name mainly because – in contrast to the typical situation of having a layer of snow on top of the ice sheet – there is only ice. The snow layer that normally covers the top of the ice sheet is blown away where the winds blow pretty fast and consistently. This means there is no good place for camp right in the Achernar area because all the blue ice is a sign of strong winds. We decide to back up a few miles to where the snow starts again and camp a little but away from Mount Achernar. This means we will have a ‘daily commute’ to get to where we want to work, but at least we have a nice place to live for the week. It is less windy where we decide to set up camp and a nice layer of snow in which to pitch the tents and walk around. Blue ice is very difficult to walk on – it is just what it sounds like – walking on ice!

Setting up just another field camp at Mt Achernar

We set up camp. Unlike at Mount Howe, here each person will have their own tent. In addition, we set up the bathroom tent and a huge kitchen tent, named the ‘Arctic oven.’ The arctic oven will act as a kitchen and dining area. It is about 25 feet long, enough to be comfortable. And, when we have two stoves going inside, the temperature gets up to a comfortable 60 degrees or even higher (hence, its name); comfortable enough to start peeling off all our jackets while eating. Two little speakers that Tim picked up in an airport, attached to ipods, means we even have a stereo system in the arctic oven cook tent.

The first day we drive out to where we want to work. It takes about an hour and a half each way by snowmobile. This is quite a bit of time. In addition, the glacier deposits we want to study are much larger in area compared to at our first site at Mount Howe. It is not practical for us to drive everywhere and get to all the places by walking. We realize we will need to utilize the helicopter from nearby CTAM. So, the next week or so we alternate: a “snowmobile day” when we commute by snowmobile from camp to the field site and “helo days”. On the helo days, the helicopter flies out to our camp (a short flight by helicopter from the CTAM camp) picks us up, takes us exactly where we want to go around Mount Achernar, and then at the end of the day, comes back out to bring us back to our camp. All these trips only take the helicopter folks about 75 minutes in total each day, given how fast they go.

Collecting samples from the top of boulders that got left back by the retreating glaciers. At home in the lab at Lamont, we will use a method called 'Surface Exposure Dating' to figure out when the ice sheet left these boulders behind when it retreated.

We spend the next 8 days or so doing the same sort of work as at our first site Mount Howe. We map the glacier deposits (how red or oxidized are they – how do their elevations changes? How do the deposits themselves change in terms of shape and composition and other characteristics?). Mike K and Mike R (with occasional assistance from others) collect samples for the surface exposure dating, so they can eventually figure out how old all the deposits are. Kathy, Nicole and Tim study the composition and types of glacier rocks and sediments left behind.

Similar to our finding at Mt Howe, we find pronounced changes in the glacier moraine deposits around Mt Achernar. This indicates there are likely deposits of different ages, left behind at different times by the ice sheet when it was bigger. All the team members continue to collect samples that will be analyzed later in the lab.

Running water in Antarctica at Mt Achernar

Mike K, Kathy, Mike R, Nicole and Tim

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