If you went to Greenland, almost 80 North,
And drilled your way down … a mile, then more,
You’d find some strange layers, a story’d come forth
A record of ice ages locked in a core.
You’d find glacial ice that is clearer, more soft
Than Eemian ice (long crystals, more rigid)
And clues that the ice height was higher aloft
Than thought for that time (with air temps less frigid).
A puzzle indeed, this view down a hole –
If NEEM endured warmth, whence the sea rise?
Some question the records, some look to South Pole …
In the decades that come, are we in for surprise?
This is one in a series of poems based on science news, written by Katherine Allen, a researcher in geochemistry and paleoclimate at the Lamont-Doherty Earth Observatory. “Greenland Ice” first appeared on Allen’s website on Jan. 25, 2013.
Armin Van Buuren, Ancient Wood, and Ghengis Khan: This is not your father’s field research in Mongolia
We never expected this. Enkhbat had us hovering at warp speed along the Millennium Road in the northern shadows of the Khangai Mountains. Armin Van Buuren’s A State of Trance filling our rig. We were starting a new project to study the interaction between climate, fire, and forest history in the land of Chinggis Khaan and a silky voice was lifting us higher, “and if you only knew, just how much the Sun needs you, to help him light the sky, you’d be surprised. Do…do…do.do”. We were exhilarated. The Sun was shining. This was not exactly Chinggis’ steppe. But little did we know, we would eventually be chasing his ghost.
Byarbaatar & Amy in front of Khorgo, unknowingly about to meet Chinggis’s ghost. Photo credit: Enkhbat.
After about a day’s travel we started passing the Khorgo lava field. Amy asked, “What’s that?” Neil had forgotten about this landmark despite having walked upon it 10 years prior. It is a ~30 km2 lava field with old trees on it. Gordon Jacoby, Nicole Davi, Baatarbileg Nachin, and others had sampled in the early aughts and put together a ca 700 yr long drought record from Siberian larch. Neil relayed this information to Amy and she said that we should sample on it knowing that a 2,000 yr long record in the American Southwest had been produced on a similar landscape feature. We had a tight schedule, but as we drove out to the western edge of the Khangai’s, sampled sites, witnessed a sheep in the dying throes of a brain worm infection, got snowed on, and then sweated in much warmer temperatures, we decided it was worth the time to see what was out there. Little did we know.
By the time we arrived to start sampling, Neil was getting sick (we learned days later that Neil was coming down with tonsillitis) and we were on fumes from some bone-challenging swings in the weather. Amy pushed on during the first day with Byarbaatar and Balginnyam. The found a pile of dead horse bones and couldn’t get the chainsaw running stopping them from acquiring samples from downed, dead trees. It felt almost hopeless.
We summoned our strength the next day and explored a new section of the lava field. Soon after getting out there we starting seeing Siberian pine, a tree Neil hadn’t seen on his first visit and hadn’t been sampled previously at this site. We decided that after our fire history collection we would sample some pine trees just to see what They might have to say.
The Logo Tree: The Siberian pine that clued us into the possibility that there might be something extraordinary on the Khorgo lava field. Photo credit: Amy Hessl
As this collection wasn’t priority, these samples sat until late January of the following year. Here is the first email of the discovery (partially redacted for some sensitive language).
The sample “locked in and said the inner ring i measured was 1235…whoa! that was cool b/c i started a good bit from the pith…. i race back to me scope and measuring stage…..make mistakes. going too fast. fix the mistakes…..the PITH is 1142!!!!
yes, i can see the yr Chinggis was born. i can see the yr he died. i can see the yrs Mongolia rose to rule Asia!
this has been our Holy Chinggis during the entire Mongolian project.
this is totally hot censored.
ps – i guess we are going back to Khorgo, huh?”
KLP0010a – the first sample of Siberian pine from the 2010 Khorgo lava collection to break the 1200s. The pith is 1142 CE (Common Era). Photo credit: Neil Pederson
We secured funding and we went back to Khorgo in 2012 with a bigger crew and one goal in mind – collect more wood.
We cannot believe what we have found.
For centuries, common wisdom held that the Mongols were driven to conquest because of harsh conditions – drought. Our new record, dating back with confidence to 900 CE (Common Era), indicates the opposite. After the unification of the Mongols, Chinggis Khan, you know him as Ghengis Khan, led his army from Northern China in 1211 to the Caspian Sea in 1224 CE. Our new record in PNAS indicates that it was consistently wet from 1211-1225, a period we are calling the Mongol Pluvial (look for an open access version of this paper here or contact Amy or me). No years during this period were below the long-term average, which is a singular rare run of moisture conditions in our 1,100 year long record. Independent tree-ring records over extra tropical Asia also indicate that this period was warm.
On the cool semi-arid steppe of Central Asia, water is life and in those days, water was energy. The Mongol diet is heavily based on the meat of grazers. Their mode of transportation was the short, but Pheidippidic horse. So, for food and for travel, grass is life. Grass is energy. An abundance of moisture would seem to provide the horsepower for the rapidly growing Mongol Empire. The Mongol soldier had five steed at their disposal. With a large army, that quickly translates into a huge herd and a huge need for grass.
Our tree-ring record suggests that the grasslands of central Mongolia were likely productive. They strongly agree with satellite estimates of grassland productivity. Going back in time, then, the trees would suggest the Mongol Empire during its rapid expansion was sitting in a sea of grass, a sea of energy, a potential abundance of life.
That is our hypothesis, anyhow, and something we will test in the coming years with historical documents, environmental records from lake sediments, more tree rings, and ecological modeling experiments.
While this record speaks to a rapid transformation of Eurasian culture during the 13th century, it also speaks about an abrupt transformation in Mongol culture today. Towards the end of our tree-ring record we see a prolonged drought from the end of the 20th century into the beginning of the 21st century. This drought followed the wettest century of the last 11 and occurred during the warmest period of the last 1,100 years in Asia. The abrupt transition in the environmental conditions, a transition that saw hundreds of lakes and wetlands disappear from the landscape, occurs during the transition from a more agriculturally-based economy to a more urban-based economy. These severe conditions, in combination with some harsh winters, killed millions of livestock and are thought to be one trigger of a mass migration of Mongols from the countryside into the capital of Ulaanbaatar.
Ulaanbaatar in 2006. The homes on the far hills likely reflect climatic and economic refugees moving from the countryside into the city. Photo credit: N. Pederson
Though we cannot connect this heat drought to climate change (though maybe we kind of can), warming temperatures have stacked the deck towards higher evaporative demand, so even if the amount of precipitation remains the same, high temperatures will generate a more intense drought. That’s what we observed in the early 21st century and based on past moisture variation in Mongolia and future predictions of warming, we would expect to see similar events in the future.
From Armin Van Buuren to Chinggis Khaan to Armin Van Buuren again. We had no clue of how Summer 2010 would light the sky.*
* this post was requested by a media outlet so they could have the ‘author’s voice’ on this discovery. That version was ultimately sanitized for your protection. Here it is unadultered.
Humans hate to catch the flu,
But here’s a fact that’s less well-known:
Bacteria get infections too
As many cultures have now shown.
In the ocean, P. ubique
(growing, growing everywhere)
Is plagued by viruses that seek
To hijack ubique’s gene hardware.
The key to beating strong predation:
Nutrients and conjugation!
Abundant SAR11 viruses in the ocean, Zhao et al., Nature (2013)
This is one in a series of poems based on science news, written by Katherine Allen, a researcher in geochemistry and paleoclimate at the Lamont-Doherty Earth Observatory. First posted 2/15/13 on Allen’s website.
To record these lower-crustal and upper-mantle phases as “first arrivals”, where they are not obscured by the arrival of energy from shallow paths, we use long lines. Long lines mean lots of receivers and lots of driving to deploy and recover these instruments. We could have used lots of sources instead, but the blasts we used to get seismic energy into the lower crust and upper mantle in this experiment take a lot of time and money to setup. Receivers are much cheaper, so we used a lot of them. (For similar wide-angle/long-offset work at sea, airgun sources are cheaper than putting seismometers on the seafloor, so we use many shots and a smaller number of receivers out there.)
This time-lapse video shows Team 13 of 14 recovering 89 of the 1200 total short-period seismograph stations from where our line crossed Fort Benning, near the northwestern end of the line.
Nathan Miller, LDEO
Weather map during deployment. When the time came to install our 1200 small seismographs across Georgia at the flagged positions, the rains came…. A lot of rain. During our first deployment day, we received 1-2 inches of rain, and another wave of rain clouds came through on Day 2 (check out map). Roads that used to be easily passable became mudholes or were flooded with water. All-wheel-drive vehicles and drill rigs alike got stuck, and a few station locations could only be reached on foot. Our hard-working field crew labored in the rain digging holes and deploying seismometers. Vehicles, equipment and people were covered in the famous Georgia red clay (and other muds and sands of Georgia and northernmost Florida). Adding insult to injury, problems with the programming of some of the instruments meant that we actually had to pick up and redeploy many of them. It was a mudbath. Nonetheless, our field crew managed to deploy 1200 seismometers across Georgia by Tuesday at sundown. It was an impressive show of endurance, and an inspiring display of positivity given the number of people that were still smiling and upbeat at the end of it all. A couple of days later, after our seismic shots, it was already time to pick up the instruments, and the weather changed completely. The sun shined on SW Georgia, and we picked up almost every last seismometer in just one day under blue skies…. Donna Shillington, LDEO
To someone who hasn't seen a seismic source shot before, there really isn't a good way to describe what a good shot feels like, except as something you haven't felt before. We had a number of students watching L1-05 being shot, since this location is quite close to Americus. The video of L1-05 is completely lacking in drama, which is a good thing; but that shot gave us all a great ride. The 100 pounders 06 and 07 were also surprisingly good.
We made gathers for most of the shots today. The dataset is fantastic, and 05, 06 and 07 produced super record sections. L1-08 committed most if its energy to the air, but it shook the ground nicely and I've got a feeling those data are going to be great too.
The video is here: http://youtu.be/DNINWj2kf1s
Gliders and buoys and robots — oh my!
Over and through the ocean they fly.
Oodles of data from sensors galore,
Studied by many, far from the sea’s roar.
A real revolution, there seems little doubt,
But what of the crew who never sail out?
To peer in the great briny main without drinking …
How might that impact the next wave of thinking?
A Sea Change for U.S. Oceanography, Science 2013
The New Generation of Sea Scientist, Science 2013
This is one in a series of poems based on science news, written by Katherine Allen, a researcher in geochemistry and paleoclimate at the Lamont-Doherty Earth Observatory. First posted 3/1/13 on Allen’s website.
South-central part of the seismic line. The yellow line is team 5's section. We have been in a relatively rural part of Georgia and as a result have not encountered many locals save a few who have stopped to ask if we are ok. However, we have seen quite a few interesting things that are quite out of the ordinary (to me at least).
Friendly Muscovy duck.Rocks in a stream bed with associated pink spongy material (?)
Spanish moss.Linguoid (current) ripples on a washed out road. We have also seen quite a few old abandoned farm houses in various stages of aging...
At least 10-15 dogs were standing guard at this house, including about 8 puppies.
Caroline making some new friends.
All said we have dug 122 holes in team 5's stretch. We have also helped deploy instruments in other sections as well and while doing so have seen others hard at work.
Meghan and Nate getting it done!Along the way the cars have taken quite a beating and have actually held up pretty well. Although there have been a few instances where people got stuck, I think that the people with the toughest job will be the guys that have to detail the cars upon their return...
A more appropriate vehicle (?)And lastly here's a couple more random pictures that I thought were interesting.
The large disparity in fuel grade gas prices.
A ~perfectly leveled geophone (it's harder than you'd think).Hopefully this random selection of pictures was entertaining. Up next we will post about last night's "shots." In the meantime, I can say that they were all successful with varying degrees of excitement. The most important thing is that all of our hard work is being realized as the instruments are recording refractions from buried geology that will help us unravel some of the mystery that surrounds events that happened in this area long ago.
James Gibson, LDEO
Chastity AikenGeorgia Institute of Technology
into the field where they undoubtedly got a little mud on their tires. Each pair of field assistants was given a segment of the seismic line to drive and flag locations for instrument installation deemed safe both from the seismograph (i.e. dry, firm soil) and the install team (i.e. a safe distance from the road). Given the shear distance of the seismic line, teams found themselves amid diverse backdrops from rolling farmland with overly friendly cows to buzzing residential neighborhoods to sandy stretches flanked by towering groves of Ponderosa Pine trees. Antonio placing a flag and using a GPS device to note the location where a
seismograph will be installed amid the sandy surroundings of a Ponderosa Pine farm.Every team was able to flag all their sites within just two days leaving us the luxury of a sunny Saturday morning free for exploring more of our beautiful Georgia surroundings. Next up is the actual task of installing the 1200 seismographs which will involve twice the people, six more (temporarily clean) vehicles, and of course countless exciting adventures from the field. Happy (almost) St. Patrick’s Day from Americus!A picturesque county road near Jasper, FL along which instruments will be deployed.-- Natalie Accardo, LDEO
Adrian Gutierrez, 13 March 14
7:30 am: Leave Georgia Southwestern State University, where we are staying, and head to the site8:20 am: Arrive at site 8:30 am: Start drilling and take geological samples every 5 ft.
9:00 am: Dyno Nobel truck arrives; load emulsion into cut PVC pipe sections that serve as a holders for emulsion. 9:30 am: Surprise visit from other scientists on the project9.50 am: Setting up the booster in the emulsion.11.20 am: Loading the explosives into the drill hole12.00 pm: Drill crew starts removing their equipment12.45 pm: Tagging the charges and plugging the hole3.15 pm: Move onto the next drill site.Nighttime: Finally back to the dorm.
An ancient grain of zircon found
In Jack Hill sandstone north of Perth,
Inside its crystal lattice bound:
Secrets of our planet’s birth.
The oldest grain (we rock hounds swoon),
Tells of magma oceans past,
An early impact yields the moon;
And all of this occurred so fast!
The zircon’s old, which then implies
That solid rocks must be still older.
In Canada, a sequence lies,
With implications even bolder!
A pattern locked within old lava
Echoes patterns from the deep;
Mariana-like subduction …
To plate tectonics, take the leap!
Hadean times are cloaked in intrigue,
Eons distant, full of strife,
Yet it seems these rocks held promise,
Full of boron, primed for life!
In the news:
New Record for Oldest Earth Rock, Sky and Telescope
Hadean age for a post-magma-ocean zircon confirmed by atom-probe tomography, Nature Geoscience
The Dawn of Plate Tectonics, Science Now
Fortunately, we have a lot of space! Our field headquarters is located in a historic gym on the campus of Georgia Southwestern State University in Americus, GA. Faculty and staff at GSW have been extraordinarily generous with their time and expertise. They are allowing us to use the Florrie Chappel gym as our base of operations, and they have helped us enormously with Georgia geology and logistics coordination, handling our huge shipment of equipment and supplies, housing on the campus (many of us are staying in one of the dorms!), setting up the gym with internet access, power, and tables, and much, much more. Today, they moved all of the boxes with our seismic equipment from the shipping warehouse to our field headquarters in the gym. I can sense that all of our seismic instruments are itching to be deployed....Pallets waiting outside the Florrie Chappell gymDonna Shillington
11 March 2014
To prepare for our big seismic experiment, we have collected a couple of miniature seismic datasets. The shallow geology varies substantially along our profile and is very important for planning the depth of drilling and size of our seismic sources. In particular, we need to determine the depth to a limestone layer in a few places. The same seismic method that we will use to understand the deep geological structures beneath Georgia can also be used at a smaller scale to examine layering in the upper ~100 ft (~30 m) beneath the surface. We recorded the data on 24 geophones attached to a 230-ft-long (70-m-long) cable. The source was a modified shot gun that looks like a pogo stick. We drilled small holes in the ground, loaded the gun and stuck it in the hole. To limit the kickback, we weighted the gun down with a metal plate topped by two heavy jugs filled with sand. Hit the plate with a mallet and – BANG – a seismic source! Not a bad way to spend a sunny Sunday!
Check out Dan firing the seismic source...
9 March 14
Satellites cast their wide gaze
At night, on the bright Bakken blaze;
Bright as a large, sparkly city,
Up close, it’s not quite as pretty.
What fate might this appetite bring?
In government halls, squabbles ring.
Key to the carbon debate
Is the last Termination’s change rate.
What’s our scenario worst?
Was warming or CO2 first?
New ice core studies profess
A 200-year lag — or less.
A puzzle to solve ere we burn:
The process of compacting firn.
Synchronous Change of Atmospheric CO2 and Antarctic Temperature During the Last Deglacial Warming, Parrenin et al., Science 2013
Leads and Lags at the End of the Last Ice Age, Brooks, Science 2013
Study of Ice Age Bolsters Carbon and Warming Link, Gillis/NYT 2013
A Mysterious Patch Of Light Shows Up In The North Dakota Dark, Krulwich/NPR 2013
The New Oil Landscape, Dobb/National Geographic 2013
This is one in a series of poems based on science news, written by Katherine Allen, a researcher in geochemistry and paleoclimate at the Lamont-Doherty Earth Observatory. First posted 3/1/13 on Allen’s website.
It was time to pack up and leave. Shofiq, who is from Sylhet, was dropped off near his home and the fellowship of the rocks was broken. We settled in for another long drive. We made an impromptu stop at one of the numerous brick factories scattered across Bangladesh. Here, the workers immediately started snapping pictures of us with their phones. We walked past the rows of drying unfired bricks to the massive kiln built from the bricks themselves. We saw them feeding coal into the hot, actively firing part and unloading bricks from the completed quadrant. This would be followed by loading of raw bricks for the 12-hour firing. This factory makes around 9,000,000 bricks in the six-month season. Although it was their lunch break, they demonstrated the mixing of the mud with a little sand and let me carry a half-full wheelbarrow load to where the bricks were
shaped. I spilled a full load when I tried to move it. The experienced brickmakers took about 30-seconds per brick.
We stopped for lunch at the same roadside restaurant, then went to find Wari-Betashwar. Getting to the archeological site was not easy, but a mixture of my hand-held GPS with a Landsat image and a Bangladeshi phone with completely inaccurate Google maps eventually got us there a little after 4 p.m. We toured the site with the chief archeologist, but all the excavations had been filled in to protect them during the off-season. As we walked around the 600m by 600m protective wall, Prof. Rahman explained the history of the site. This urban
center was founded around 500 BC on land slightly uplifted by one of the anticlines. The slight extra elevation protected the land from flooding. The site was by the side of an old path of the Brahmaputra River and was thus a major trading center. Artifacts from as far as Greece and Rome were found here. After a gap in the record, the city flourished again in the 7th century AD, before being abandoned. The rise and fall of the center may be tied to avulsions, or switches in position of the Brahmaputra, making the site an interesting confluence of tectonics, rivers and people.
Continuing on, the students got a taste of Dhaka traffic as we approached our hotel near the airport. Now came the real
splitting up of the group. The foreigners would stay overnight to begin our return home, while the Bangladeshis would fight the traffic to return to Dhaka University and their homes. Many of us spent most of the time until our 2:30 a.m. departure talking. Twenty-three of us and our luggage and equipment managed to squeeze into a 21-seat bus and made it to the airport. Now, once again problems with our tickets arose. While most of us were fine, almost half only got boarding passes as far as Abu Dhabi, or none at all. Eventually they fixed the problem for most of them, and all of us were able to board the delayed aircraft. The delays here and in the flight to New York and Chicago will mean that the vast majority will miss connections. At least my nightmare scenario of missed flights and connections was happening on the way back. Not the smoothest ending, but it has been a great trip and a very successful field school. Several of the students are trying to figure out how to get back to Bangladesh, and a lot of lasting friendships and connections have been made.
The drive from Tangail to Sylhet turned out to be grueling. We took a longer route that skirted Dhaka to avoid the traffic jams that people hit earlier in the week. Unfortunately, with the slower buses that route took 13 hours. We didn’t hit our lunch stop until 4:30 p.m., where Badrul and Ashraf had been waiting to join us for five hours. It was dark by the time we drove past the first anticlines, and we didn’t get to the resort until 11 p.m. We picked our roommates, got our rooms and had a very late dinner. Most field trips have a “death march” hiking a long way through forest, swamps, hills or deserts to get to a remote outcrop. We have a “death bus ride” instead.
The new resort where we were staying was tucked away in a corner of Bangladesh along the Shari River about a kilometer from the Indian border. With a cold pool and only slightly warmer not-hot tub, views of the woods and hills, this is by far the nicest place I’ve stayed in Bangladesh. Given the late arrival, we delayed the start of the classroom day by an hour. The classroom was in a separate building closer to the river The first classroom day covered the stratigraphy and structure of the sediments and rocks we would see the next day. With lots of questions, the day ran late.
We started early and argued over an outcrop on the driveway of the resort. We continued down to the Shari River, where I had previously visited the geology by boat. Numerous
country boats were mining and transporting sand from the river. We worked along the shore, climbing over and visiting outcrops. The beds dipped steeply into the ground, folded by the tectonics, but also provided evidence that a large braided river used to flow here. One possibility is that it was the Brahmaputra from a time before the uplift of the 2 km-high Shillong block pushed it 200 miles to the west. Eventually, we could not go farther along the river. We took an inland path farther north, but when we rejoined the shore, we were blocked again. A short time later, after a conversation with the Bangladeshi border guards stationed here, they flagged us a passing boat. It ferried us across the river, but not before
several on our party practiced their cliff jumping technique.
After spending some time on an outcrop where we were filmed last year, we took an inland path. Along the way we met Johnny the elephant, and a few groups of students got elephant rides. We continued past tea gardens and rice paddies and finally emerged to a large outcrop of shallow marine sediments along the river. At this earlier time, the coastline was north of us, and the delta was prograding to the south as a result of all the sediments eroding from the Himalayas. The younger river sediments we had seen earlier had been deposited after the coast had pushed past here. We stopped for lunch, looking across the river at the India-Bangladesh border and a pile of watermelons waiting for a
boat to take them downstream. Two students swam across and purchased two for dessert. Then Badrul flagged down a large boat to taxi us downstream back to where we started.
After a few geology stops along the way, we reached Jaflong. At this site, there is a mixture of mining of sands and gravels from the river, and tourists looking to view the massive Shillong uplift in India. We stopped at an overlook near our GPS and seismology stations. Then a group of us descended to some outcrops and the chance to join the tourists at the international border. The river had shifted a little since I last was here, and now the best viewing site was officially in India. The Indian and Bangladeshi border guard let us and everyone else cross the
border to the little spit of land for a better view. Many photos later, we walked back to the buses and returned to the resort. Dinner was delayed and about half of us took the opportunity for a dip in the freezing pool to rinse off the sweat and grime.
Our final classroom day conversation included multiple aspects of the interaction of the rivers and the tectonics that our project focuses on. We ended with several students presenting their research from places across the globe. The last item was a group photo close to the Shari River. The last field day took us farther southwest to Sylhet City itself. The Cricket Stadium is surrounded by outcrops that we walked around, passing a pet monkey as well. After lunch at the stadium and a peek inside, we had to make a decision. There was not enough time for
both the outcrops at the airport and shopping in Sylhet. The group split, and each bus went to one of the sites. I chose the outcrop. The river sediments at the airport were clearly different from the stadium and showed that the sediments were deposited while the 80m-high Sylhet anticline was growing. They were muddier where the anticline was tilting the land northwards, and sandier with gravels on the other side of the anticline where the southward tilting had steepened the river. We headed back, stopping to at least buy some tea from the region. However, we got back too late to hold the bus vs. bus cricket match. Just some practice would have to do, until the BBQ that evening.
We have just arrived in sunny Americus, GA from the cold north to ramp up for the SUGAR project. The peaceful, pastoral landscapes of southern Georgia mask geological structures created by a series of dramatic events that were central to the formation of the North American continent. During SUGAR, we will use sound waves to image these geological structures. Less than 2 weeks from now, we’ll deploy 1200 small seismographs along a 200-mile-long line that extends from north of Columbus to south of Valdosta with the help of a cadre of students from across Georgia and beyond. These instruments will record sound waves generated by a series of controlled blasts in deep drill holes.
Spanish moss lined trees along our transect south of ValdostaCollecting these data will involve a week of intense work by >30 people. However, just laying the groundwork for this effort has already required a long list of (sometimes novel) tasks. When we conceived of this project, we drew a couple of straight lines on a map that would enable us to capture the geological features that we wish to study: the South Georgia Basin, the Suwanne Suture, and frozen magmas from the huge Central Atlantic Magmatic Province. In reality, we must create this line by knitting together a patchwork of roads. During a couple of planning trips, we bumped along on dirt roads, cruised county lanes, and zoomed down state highways mapping out the best route.
Dan and Steve scouting our route. Our seismometers will line county and state roads across southwestern Georgia, and both seismometers and seismic sources will cross private properties. Identifying private landowners to request permission has transformed us into detectives. In most cases, the name and address of the owner are easily found on the tax assessor's website for each county. But actually getting in touch with people is not so easy! We mailed letters. We put flyers directly into people’s mailboxes. We searched for phone numbers online and left messages (sometimes multiple messages…). We found websites and email addresses for companies, and sometimes wrote to people about our project through website forms (including those for a bank, a dentist's office and a website selling organic beef!). Happily, once we made contact, individuals and companies have been very welcoming and graciously granted us permission – southern hospitality in action! A litany of other preparations have already been completed or are currently underway. Drilling of the holes for seismic sources has just begun, and the seismometers will arrive very soon. We are definitely ready for the transition from preparing to doing....
5 March 2014
It has been an incredibly busy week. We have had between 42 and 48 people here for the field school, including 35 students and 12 instructors (seven to 10 at a time). The first day was very light for the jet-lagged students, just a short introduction to the field school and some background, and then introductions all around as we started to get to know each other. The final group of nine students finally arrived around 9 p.m. They were the most worn-out, bedraggled bunch of travelers I have ever seen.
After a good night’s sleep we started on the first classroom day. Our full five days near the Brahmaputra River would focus on the river processes and the stratigraphy they produce. We stopped the lectures at 4 and all piled into the bus
to see the embankment built to protect the city of Sirajganj from the westward migrating river. As is often the case in the dry season, they were repairing the embankments from last summer’s collapses. We rented two country boats and sailed along the embankment and walked back to the buses on the top of it. It is an impressive structure, but in need of continual repair to keep up with the river.
The next two days were spent on the river and its mobile islands, called chars. Setting up the equipment for the river surveying was hampered by a lack of power for drilling holes. A Bangladeshi drill and bow solved the problem, but not before rearranging the schedule. On the first day we all visited the char near the 5 km
Bangabandu Bridge over the river. We spent the day viewing sedimentary structures and seeing the villages on this island that is almost entirely underwater during the monsoon. For the second day, we had to split the group. One contingent joined Jim Best as we surveyed the river with an ADCP, which measures water velocities from the top to the bottom of the river, and a sidescan that provides images of the bottom on either side of the boat using sound. The other, yielding to student requests, went to Tangail, the nearest city, for shopping. When everyone returned, we held a cricket match, with most Americans learning the rules on the fly. We finished the five overs per side as darkness fell.
We went back to the classroom the next day for more lectures on remote sensing of changes on the delta, stratigraphy,
subsidence and arsenic contamination. The hands-on experience was analysis of two sets of well samples that had been drilled the days before. Everyone had a chance to describe the samples, measure magnetic susceptibility and use a portable XRF machine to measure chemistry. We have found that magnetic susceptibility and strontium content are a good way to characterize whether sediments have come from the Brahmaputra River or not.
Finally, our last field day here was doing a resistivity imaging survey over the two bore holes and across the boundary between the Brahmaputra floodplain and the upland strata of the Madhupur tract. Generations have debated whether the transition is a fault contact or not. We would collect some data to try to answer the question. The students also got
to visit another tube well being drilled. Tube wells, drilled primarily for drinking water, is a local drilling method whereby a team of a handful of people can drill a 100m well in a day by hand. After everyone helped set up the 750m long resistivity line, most of the American students went to see the tube well drilling. The Bangladeshis, who have all seen tube well drilling, stayed with me to help run the resistivity line. As it turns out, Liz Chamberlain was pulled into a local villager’s home to have her hands tattooed with henna by a woman and her daughters. She missed the tube well drilling, but gained an exciting personal experience. It was also the first time the students were in a Bangladeshi village. We were the center of attention and many photos were snapped by both sides. We gathered up the resistivity equipment and then had informal student
presentations before the final night barbeque. We had successfully completed the first half of the course, and all the students (and instructors) were bonding.