Monday June 24, 2013

This week was all about sediment description and core logging. We visited three different sites and described a rock core, which is part of an ongoing project at UNIS. This week the focus of the class shifted to coastal environments in the modern and ancient sedimentary record. Bernadette Tessier, an expert on tidal systems and researcher from the University of Caen in France, was the invited lecturer for the week.

During Monday’s lecture we discussed continental shelf deposits, deltas, and tidal settings. Bernadette shared the results of a recently published study on the southern coast of the English Channel. By analyzing sediment cores and seismic profiles they found evidence of enhanced storm activity happening every 1500 years during the late Holocene, an occurrence that has been documented in other parts of the North Atlantic. In the afternoon, we visited the outcrops right next to the main road in Longyearbyen to draw our first stratigraphic column. These outcrops form part of the Carolinefjellet Formation, a marine succession composed of interbedded shales and sandstones deposited during the lower Creataceous.

On the second day, we traveled by zodiac (small rubber boat) to Deltaneset, located 15 km northeast of Longyearbyen, on the south edge of Isfjorden. The area is characterized by small capes or headlands with outcrops in the inner side that are usually exposed during the summer, usually. Unfortunately for us, most of the outcrops were covered by a lot of snow and so our first task of the day was to walk along the gravelly beach to find exposed outcrops suitable for vertical logging. It was a long walk but we found three good sites, with some snow but little enough to shovel. The outcrops correspond to the continental De Geerdalen Formation (upper Triassic). The surface is covered by cobbles and boulders, up to a meter in diameter. These have been carried by snow avalanches and debris flows from the nearby hills. A contrasting view is the soggy soil; some areas are very damp because the uppermost portion of the permafrost is thawing due to the summer warmth.

Students walking along the beach, next to snow-covered outcrops at Deltaneset.

 

The boat ride can be cold and wet and therefore students are required to wear dry suits for safety.

The following day we did not go out to the field, instead we spent the day describing and logging a segment of a rock core from the De Geerdalen Formation. The core is part of the UNIS CO₂ capture and storage research project. They have drilled 6 wells and are currently studying 4 of them for reservoir characterization. The objective of this project is to evaluate the possibility of storing carbon dioxide in the Adventdalen valley, about 5 km outside of Longyearbyen. Several master and PhD students as well as senior researchers from UNIS form part of the project. Our job was to describe the sediment, divide into facies, create facies associations, and then interpret the facies. Overall, the segment was a coarsening upward section, from muddy bioturbated to sandy cross-bedded sediments possibly indicating either transgression or lateral migration of the environment.

Student logging a 5-meter section of a core.

Adventdalen valley, approximately 5 km across with an estimated 60 meters of quaternary fill.

Thursday was a field day, we went to Endalen. A U-shaped valley located just outside of the city, with a braided river tributary to Adventfjorden. Again, the task of the day was to draw a stratigraphic column but this time the outcrops were at an elevation of nearly 400 meters along the sides of the valley. Needless to say, it took me and a couple of other students some time to hike up to the outcrops. Once there, we realized we were looking at continental deposits, in fact we were describing the same coal seams that are currently mined in other areas in Svalbard. The coal deposits correspond to the Tertiary period and in total there are five in Svalbard but only two are economically workable, one in Longyearbyen and the second one in Svea. The outcrops were also characterized by soil horizons alternating with sandstones. 

Students taking a break while hiking up in Endalen. 

Students measuring and describing a section in Endalen.

The temperature last week was higher, after all we are now in summer, it averaged around 5°C and it is expected to increase a little more. This week we will be traveling to Svea, about 60 km south of Longyearbyen, to study coastal and glacial deposits. 

Mine 2 located in Longyearbyen, now abandoned but still a must see in the city.

 

Longyearbyen and Adventfjorden, view from mine 2.

Sunday June 16, 2013

The thermometer shows the temperature is slightly above 0°C but it has been snowing all day; fortunately we do not have field work today so we can enjoy the snow from our rooms while drinking some hot cocoa. It is almost summer but in the Svalbard archipelago it feels like the middle of winter, at least for a Houstonian. I am in Longyearbyen City, located at 78.22°N, 15.65°E in west Spitsbergen, the largest island of Svalbard. The city has a population of a little over 2000 and many tourists this time of the year. I am currently attending a sedimentology field course in the University Centre in Svalbard (UNIS) lead by Maria Jensen, associate professor in sedimentary geology.  Svalbard is located well inside the Arctic Circle, which explains why there is sunlight for 24 continuous hours during the summer and in the winter, the opposite happens, there is no sunlight for 24 continuous hours. This along with the 7-hour time change from Houston made it a little difficult to attain a normal sleeping schedule.

View from the aircraft down to the glaciated mountains in south Spitsbergen, the biggest island in Svalbard on my way to Longyearbyen City.

Longyearbyen City, located on a fjord valley in the Adventfjorden bay, as viewed from Hiorthhamn

I am here as part of the new exchange program between the University of Houston (UH) and University of Stavanger (UiS).  The primary exchange is for students to go between those two schools but also allows for UH students to take specialized classes in Svalbard.

During the first day of the course, all the students were required to attend a safety course. This class is designed to teach students how to work safely in areas where there might be some wild life like polar bears, walruses, artic foxes, and reindeers for example. We also learned how to handle and use rifles and flare guns, which we have to carry every time we go out to the field. Then, we were driven to the harbor where we jumped into the water to test survival suits. These suits are especially designed to float and protect against the cold water and must be worn every time we travel on small boats.

As the name of this class suggests, this is a field course and we will spend most days outside observing and describing outcrops. Usually on Monday mornings we have lectures to introduce us to the subject and in the afternoon we go on a short field excursion. Tuesdays, Wednesdays, and Thursdays are full day excursions and on Fridays we meet in the classroom to present, discuss, and compare our observations with published work on the same or related areas. My classmates come from a wide variety of countries including Iceland, Sweden, The Netherlands, Italy, Switzerland, and Indonesia. 

UNIS student accommodations. These barracks were originally built to house miners and now have been redesigned as dorms for visiting students

The first day of class, Professor Jensen along with an invited lecturer, Dr. Louise Hansen from the Geological Survey of Norway, introduced us to sedimentary processes, valley systems, and gravitational processes. The first field area is just a few meters away from the school, a pebbly river on the Adventdalen area. The river runs from a glacier into the city and out to Adventfjorden, a bay southeast of Isfjorden, the second largest fjord in Svalbard. The water is extremely turbulent and muddy. The clasts are very coarse, angular to sub-rounded, and poorly sorted. Artificial pebbly levees have been built along the river to protect the city but the river preserves mid-channel bars that were probably deposited as bedload sheets, thin deposits of poorly sorted material that move downstream.

The second field area we visited is located on the other side of the bay, around 7 km away from Longyearbyen. To reach our destination, Hiorthhamn, we had to cross Adventfjorden in a zodiac. 

This area used to be a coal mining camp in the early 20^th century and today only a few huts remain. The area is also characterized by fan deposits from slush and debris flows. The fans were composed of lobe-like structures, possibly single avalanches that have deposited unsorted material over time (from clay and silt particles to boulders of almost 1 m in diameter). The source area is a rock glacier. Some areas of the fan seem to be inactive since they are vegetated by mosses and even small flourishing plants. 

Students having lunch on fan deposits in Hiorthhamn

In our last excursion day we studied a different fan system in Todalen, north of Longyearbyen. This is a valley with a small river that flows into Adventfjorden. The source area here is siliciclastic outcrops and the grains are much smaller than in Hiorthhamn, still angular and unsorted. The channels and levees formed by the debris and slush flows are as high as 1.5 meters while the fans themselves are around 300 meters wide. Various studies have focused on the distinction between debris and slush deposits since they could be used as paleoclimate indicators because slush flows are directly related to snow.

Students at the beginning of a field day, observing modern fan deposits in Todalen

 I will be applying the lessons of this class to my own research, studying glacial siliciclastic deposits of Antarctica.  I will post again next week with more details about the geology of the region and our next field areas.

Yuribia Muñoz

UH Earth and Atmospheric Sciences PhD Student