Archive for July, 2011

Return to Vatnsdalfjall

July 9th, 2011

BLONDUOS, ICELAND – Meagen and guest blogger, Travis

We returned to Vatnsdalfjall for the second day of field work on the Monocline. The weather was the best we’ve experienced in Iceland yet.

View of the steeply dipping Monocline as it dives under the Hjallin Lens.

After a long hike through fields of sadness (so named by a previous IS student), we finally made it to our first exposure. We found lots of interesting amygdules (filled vesicles):

Vesicles half-filled with chalcedony in horizontal layers suggests that the lavas were tilted before the chalcedony precipitated.

Zeolites come in a variety of habits, including these hair-like fibers that are about 1 cm long.

We sampled and made observations all of the way to the top of the Monocline. We were quite pleased with ourselves when we made it to the top, and slightly surprised to see that it was already 8 pm! In the land of the midnight sun, field work could last for 24 hours a day.

Lindsey and Travis getting ready to head down the mountain at 8 pm at night.

After such a hard day of work, we relaxed in the evening and made plans to visit Akureyri the next day.

Travis relaxes in the hot tub.

 

Suur Strait (Moon Sound, Moonzund)

July 9th, 2011

TALLINN, ESTONIA–The Wooster Geology team in Estonia successfully returned to the Estonian capital city of Tallinn today, which means we crossed by ferry the Suur Strait between the western Estonian islands (notably Muhu) and the Estonian mainland. This is an interesting strip of water with a complicated geological and human history.

There is an Estonian dream of building a bridge or digging a tunnel across the Suur Strait to eliminate the need for the ferry line and more efficiently connect Muhu and Saaremaa to the main part of Estonia. It will not be an easy task (and it is probably too expensive to ever be attempted), but it has led to considerable study of the strait and its oceanographic, biologic and geologic characteristics. The currents are complicated as they move between the Gulf of Riga to the south and the Baltic Sea proper in the north, and it freezes solid in the winter (when it is crossed by a 9 km long ice road). The strait hosts one of the most significant bird migration routes in northern Europe, and the marine fauna and flora here is still poorly surveyed.

The floor of the Suur Strait is highly variable from exposed Silurian limestone bedrock to thick mantles of glacial till. As you can deduce from the Google Earth image, some parts of the strait are very shallow, and the deepest regions are no more than 21 meters of water. Because of isostatic rebound, the region gets shallower about 2 mm per year as the land rises.

Suur Strait as viewed from northeastern Muhu (July 2007).

Historically, the Suur Strait has been the “backdoor” to the Gulf of Riga to the south. Any navy that controls the Baltic wants to keep that backdoor open for itself, but close it to enemies. This was especially the case during World War I when the Imperial German Navy sought to trap elements of the Imperial Russian Baltic Fleet in the Gulf on October 17, 1917, during Operation Albion. Most escaped north through the Suur Strait (known then in English as Moon Sound) following carefully dredged channels lined with mines. One Russian battleship, the Slava, was severely damaged and took on too much water to pass back through the shallow strait and was scuttled.

The Suur Strait was crossed by the Germans in 1941 as they invaded the western Estonian islands (Operation Beowulf), and again by the Russians when they re-invaded in 1944 (Moonzund Landing Operation).

We made it across on one of the car ferries which ply the Suur Strait between Kuivastu and Virtsu. Like the Russian warships of old, it also follows a dredged channel through the shallow and storied waters.

View from our ferry west across the Suur Strait towards Kuivastu on Muhu island. Last ferry ride of the trip!

Reference:

Saaremaa Fixed Link – Report of Preliminary Environmental Impact Assessment – Final Draft – 15.07.2005 (Google this and you can get a thorough report as a pdf.)

A visit to Kaali Crater for our last day on Saaremaa

July 8th, 2011

KURESSAARE, ESTONIA–A dramatic geological site on our last Saaremaa day: the meteorite craters at Kaali. We hiked around the largest crater (shown above) and then visited one of the smaller subsidiary craters nearby (shown below). The main Kaali crater is 110 meters in diameter and about 22 meters deep. The meteorite was between 20 to 80 metric tonnes and was traveling 10-20 km/s. It broke up into pieces 5-10 km above the ground before the multiple impacts. The date of this event is disputed. We have seen ranges in the literature from 4000 to 2700 years ago. Some archaeologists have evidence that an ecological catastrophe followed the impacts with massive wildfires and a drop in crop production for a century. Others think there is a connection between the Kaali event and Baltic mythology. (I think it is a delightful coincidence that the Estonian place name “Kaali” used for this fiery event is coincidentally the same name as the fearsome Hindu goddess.)

To our surprise, the Kaali Museum had a thorough display on the geology of Saaremaa, including this polished cross-section through Nick’s critical Wenlock/Ludlow section.

Our last stop was a virtually abandoned little harbor at Turja on the southeastern coast of the island. It was a nice place for lunch as we contemplated how our fieldwork did not include bears and wolverines (as with our Wooster colleagues in Alaska) or gale-force winds and thick fogs (as experienced by our Iceland friends). We were quite fortunate to gather such excellent geological data with so few such adventures!

Tomorrow we drive to Tallinn to spend a day and a half, and then to Stockholm for a day in the Natural History Museum looking at comparative Silurian material. On Wednesday of next week we fly home.

Paleoecology of the Hilliste Formation (Lower Silurian, Llandovery, Rhuddanian) Hiiumaa Island, Estonia: An example of a shallow marine recovery fauna — An abstract submitted to the Geological Society of America for the 2011 annual meeting

July 7th, 2011

KURESSAARE, ESTONIA–Editor’s note: The Wooster Geologists in Estonia found enough material, and had enough time, to write abstracts for posters at the Geological Society of America Annual Meeting in Minneapolis this October. The following is from student guest blogger Rachel Matt in the format required for GSA abstracts:

PALEOECOLOGY OF THE HILLISTE FORMATION (LOWER SILURIAN, LLANDOVERY, RHUDDANIAN) HIIUMAA ISLAND, ESTONIA: AN EXAMPLE OF A SHALLOW MARINE RECOVERY FAUNA

MATT, Rachel M., WILSON, Mark A., FEDORCHUK, Nicholas D., Dept of Geology, The College of Wooster, 944 College Mall, Wooster, OH 44691-2363, VINN, Olev, Dept of Geology, University of Tartu, Ravila 14A, 50411 Tartu, Estonia

The Hilliste Formation (Lower Silurian, Llandovery series and Rhuddanian stage) is well exposed in a quarry in western Estonia. During the deposition of this unit, Estonia was part of the paleocontinent Baltica, which was located near the equator. The Hilliste Formation thus records the recovery of tropical invertebrate marine communities following the mass extinction at the end of the Ordovician. Globally, pre-extinction levels of marine diversity were not met until the Wenlock, about 15 million years after the end of the Ordovician; this formation was deposited about three million years following the event. The Hilliste Formation contains a diverse fauna including brachiopods (orthids, atrypids, rhynchonellids, pentamerids, and strophomenids), corals (favositids, halysitids, heliolitids and rugosans), stromatoporoids, bryozoans, gastropods, crinoids, ostracodes and trilobites. We measured, described and sampled the Hilliste Formation at Hilliste Quarry on Hiiumaa Island, western Estonia. The unit records a regression from depths between normal and storm wavebase to depths at or above normal wavebase. The evidence for this paleoenvironmental interpretation includes more argillaceous beds in the bottom two-thirds of the formation and more biosparite/grainstone upwards. The top third of the formation consists of massive biosparite/grainstone with little clay and overturned and fragmented corals and stromatoporoids indicating high depositional energy. The fauna changes stratigraphically upwards from one dominated by brachiopods and gastropods to a community primarily of corals, stromatoporoids and crinoids. This fauna provides additional information about biotic recovery in eastern Baltica and its implications for the migration of Early Silurian Baltic taxa into other regions.

Stratigraphy and paleoecology at the Wenlock/Ludlow boundary on Saaremaa Island, Estonia — An abstract submitted to the Geological Society of America for the 2011 annual meeting

July 7th, 2011

KURESSAARE, ESTONIA–Editor’s note: The Wooster Geologists in Estonia found enough material, and had enough time, to write abstracts for posters at the Geological Society of America Annual Meeting in Minneapolis this October. The following is from student guest blogger Nick Fedorchuk in the format required for GSA abstracts:

STRATIGRAPHY AND PALEOECOLOGY AT THE WENLOCK/LUDLOW BOUNDARY ON SAAREMAA ISLAND, ESTONIA

FEDORCHUK, Nicholas D., WILSON, Mark A., MATT, Rachel M., Dept of Geology, The College of Wooster, 944 College Mall, Wooster, OH 44691-2363, VINN, Olev, Dept of Geology, University of Tartu, Ravila 14A, 50411 Tartu, Estonia

The boundary between the Wenlock Series and the Ludlow Series can be easily observed on the island of Saaremaa in western Estonia. Here, the boundary is distinguished by a major disconformity that can be correlated to a regional regression described in several previous studies. During this time, western Saaremaa was a lagoonal facies that reflected sea-level changes within the Baltic Basin. We measured and described this Wenlock-Ludlow boundary interval at Soeginina Cliff on the western shore of Saaremaa. Here this boundary consists of the Vesiku Beds of the Rootsiküla Formation (Wenlock) overlain by the Soeginina Beds of the Paadla Formation (Ludlow). The Vesiku Beds (Wenlock) record a carbonate lagoonal environment with finely laminated beds and Thalassinoides burrows (indicating oxygenated bottom conditions). The fauna is much less diverse than that in normal marine sediments of the Wenlock. The top surface of these beds (the primary discontinuity surface) shows a microtopography and dissolution consistent with exposure and abrasion. The top 20 centimeters also show diagenetic alteration of the laminated sediments, probably from fluids traveling through the Thalassinoides burrow systems. The Soeginina Beds (Ludlow) show pulsating transgressive sediments with multiple discontinuity surfaces. Large oncoids are common in these beds. They have distinctive shapes because they were initially spherical and later stabilized and grew like small stromatolites upwards. These forms may indicate periodic energy reductions in these transgressive waters. There are also storm beds with biogenic debris including oncoids nucleated on gastropods. This boundary interval is topped by thin dolomites and stromatolites. This example of the Wenlock-Ludlow boundary can be correlated with other such disconformities recorded in a variety of depositional environments, such as in the equivalent reef complexes of Gotland, Sweden.

Inside a secret Soviet missile base — 20 years later

July 7th, 2011

KURESSAARE, ESTONIA–When I was growing up the Soviet Union was simply an unchangeable fact of life. The United States had an implacable enemy, and we were locked in a struggle that would last my lifetime, at least. That lifetime was almost certainly going to be short, of course, because sooner or later someone would push the nuclear button and, in the words of the Kingston Trio, “… we will all be blown away”.

Thus it is very much an existential treat to have lived into my sixth decade and be able to walk through the remains of a secret Soviet missile base to get to the Suuriku Cliff locality this morning. The Evil Empire collapsed, the Baltic States were liberated, and massive overgrown concrete bunkers stand as evidence of a nearly unimaginable past only 20 years old. I am privileged as a geologist to be able to travel to such places and feel the turning points of history.

While constructing this Google Earth image of Tagalaht Bay to show the location of this Soviet base (one of dozens on the island, by the way), I saw something cool in the south: ancient shorelines. Saaremaa, like most of the Baltic region, is experiencing post-glacial isostatic rebound. The land is rising at least 2 mm per year (and in some places much more), so the sea is retreating. These shorelines are only a few thousand years old.

Wooster Geologists return to Suuriku Cliff, Saaremaa, Estonia

July 7th, 2011

KURESSAARE, ESTONIA–Today we visited one of Rob McConnell’s (’10)  Senior Independent Study field sites on the northwest coast of Saaremaa. Suuriku Cliff (N58.50875°, E21.99818°; see above image) is an exposure of the Jaani Formation (Lower Silurian, Wenlock). There are two members here: the upper Ninase (most of the cliff) and the lower Mustjala. Rob sorted out the paleoecology and environments of deposition of these two members using samples from this location and two others.

We were here today to find additional crinoid calices to continue a project Bill Ausich, Olev Vinn and I are pursuing. We found a few, too, although none very photogenic. It was also a chance for us to see more examples of Silurian limestone and fossils before we leave the island on Saturday.

Nick Fedorchuk and Rachel Matt at Suuriku Cliff. We want to show that some Saaremaa cliffs really are more than a meter high!

Panorama of Tagalaht Bay south of Suuriku Cliff near Veere. This bay is where German naval and infantry forces invaded Saaremaa on October 11, 1917, in Operation Albion.

First day at Vatnsdalsfjall

July 7th, 2011

BLONDUOS, ICELAND: Guest Blogger: Lindsey

Yesterday was our first day of field work on Vatnsdalsfjall, a mountain located on the Skagi peninsula. Vatnsdalsfjall exposes lavas erupted 7 million years ago from an ancient rift located to the West. We know this because the lava flows in this area dip towards the ancient rift axis in the West; yes Dr. Judge, we used a Brunton compass! We hiked up through a sheep field to the base of the outcrop; we then continued hiking up a gulley until we started to see zeolites. The first zeolites we saw were also found with a green clay:

Green clay and filled vesicles in our first zeolite-bearing outcrop

As we climbed higher, we continued to see zeolites in a variety of sizes. Travis’s tip to me was to look for the white zeolites, as these are more diagnostic of their environment of formation (temperature). It was important to keep track of the units we were climbing up through, as boundaries between flows were frequent.

Travis demonstrates proper use of a field notebook

Because of the steeply dipping flows, we had to bear in mind that as we got higher, the units being exposed were actually stratigraphically underlying the units we had seen earlier at the base of the gully. One particular unit of note was a gorgeous plagioclase rich marker bed; it also had zeolites in it that we sampled:

Plagioclase-phyric marker bed

Overall yesterday, we sampled a total of 50 meters of zeolites, and according to Rob Lydell’s (’10) notes, we have about 50 meters left to sample today. Due to the fog we experienced yesterday morning, we decided to go out this afternoon so that we could see a little bit better:

Travis perches on a slope to take notes, notice the fog in the background!

Unfortunately, this has given me more time to dread this afternoon’s hike-Travis and I are pretty sure that Vatnsdalsfjall literally translates to “Death Mountain” in english as this is the steepest thing he or I have ever hiked.

"How do Mountain goats do this?!?!" -Travis

Not only is it steep, the loose apple to watermelon-sized talus makes every step treacherous; I bit it a couple of times and I have the bruises to show for it! I know our Alaskan colleagues probably have no sympathy as it sounds like their hiking was rigorous as well! However, the successful sampling we completed yesterday as well as the panoramic views of the valley below over PB&J at lunchtime make it well worth it.

Thingvellir and the trip North

July 6th, 2011

Blonduos, Iceland-

[Guest blogger: Travis Louvain]

So as we completed the research on the Reykjanes Penninsula, we traveled up north to the Skagi Peninsula to a town called Blonduos.

Car pictures are always a necessity.

On the way we stopped at a place called Thingvellir. This site is home of the first Icelandic Parliament and a beautiful national park.

A beautiful stream that cuts right through the middle of the main fissure.

The place was chosen by the early Icelanders because it was relatively easy to access and because it is a amazingly flat valley. Why is this? Well that’s where the geology comes in. This national park is not only home to the first parliament but also it is a site of active rifting.

 

Path through the middle of a large fissure leading to the site of the original parliament. When it met they used to make speeches from the taller side of the fissure to a crowd listening on the other side.

So the flat valley is actually the result of the two plates rifting away from one another. This can clearly be seen in the large fissures which are a highlight of this site.

 

Large fissures run through the ground all over the place. Some are only a foot deep, but some drop for tens of feet.

The rift valley from atop the large fissure.

After this we continued driving north mostly along the coast. At one point we went under a large fjord by way of tunnel and under the following mountain before coming out on the other side where we stopped for lunch. As we drove we saw many sheep and horse farms. We also drove up into the mountains where the mountain tops were still covered with snow.

Snowy mountaintop. We continued seeing sheep roaming even at these high altitudes.

As we drove to Blonduos we passed my field site and decided to ask permission to go up the mountain side. As I sat in the car wondering whether or not I was going to have an I.S. or not, I couldn’t help but laugh at Dr. Pollock making gestures with her arms while talking to the lady who owned the land. It turns out that the lady spoke English fairly well and Dr. Pollock was just using large hand gestures cause she liked to, but the good news was that she gave us permission to go up the mountain.

After this, we continued to Blonduos which happened to be very close. We checked in to our cabin which was complete with a kitchen, bathroom, fridge, propane grill, and a hot tub. Yes, a hot tub!

Well to wrap up today I finished a video that I’ve been working on from our fourth day where we explored the southern portion of the Reykjanes Peninsula. I hope you enjoy it.

The Southern Reykjanes Adventure

The painful history of the Sõrve Peninsula, Saaremaa, Estonia

July 6th, 2011

KURESSAARE, ESTONIA–This country has had the historical misfortune to lie between the Russians to the east and the Germans to the west with all their imperial ambitions in the last few centuries. The terrain is deeply glaciated and thus has few natural defenses beyond thick forests, extensive bogs, and rocky coastlines. It has been occupied by Crusaders, Swedes and Polish-Lithuanians besides the multiple incursions of Germans and Russians. The 20th Century has been especially painful for Estonians.

Yesterday the Wooster Geology Estonia team worked near Kaugatuma on the proximal end of the Sõrve Peninsula on the southwestern tip of Saaremaa Island (see the images above). We then traveled south down the full length of the peninsula to Sääre. We visited a small, eccentric military museum and learned much about the history of this region. I think this strip of land is emblematic of the recent historical travails of Estonians — and thousands of Russians and Germans as well.

This is a panoramic image looking from the top of an old Russian gun emplacement looking south to the end of the Sõrve Peninsula at the village of Sääre. For a larger view of this panorama, please visit the Sõrve Peninsula Wikipedia page. This peninsula, by the way, has only been connected to Saaremaa for about 2500 years. It and the other eastern Baltic islands are still rising from the sea as a consequence of post-glacial isostatic rebound.

On the left Rachel and Nick explore a massive concrete gun emplacement near Sääre. These were built by Imperial Russians to house the 12-inch guns shown on the right in a museum image. These guns commanded the western entrance to the Gulf of Riga. They were captured by the German Army in October 1917. Note that this was a World War I battle.

The Soviets occupied and annexed Estonia in 1940 following the secret protocols of the earlier Molotov-Ribbentrop Pact. Nazi Germany declared war on the Soviet Union in June 1941, and in October turned its attention to conquering the Baltic islands. In November 1944, the Soviets returned and re-invaded Estonia and its islands. Some of the fiercest fighting took place in the Sõrve Peninsula in both invasions, as can be seen in the above maps photographed at the Kuressaare Castle Museum of Saaremaa. Note the November 1944 Russian amphibious landing at Kaugatuma. You can see why the Sõrve Peninsula has a significant number of landmines still remaining in the undeveloped forests. (Since 1999 there have been at least 77 casualties from landmines and unexploded ordnance in Estonia.)

A Soviet artillery observation post (from the 315th Coast Guard Battery) disguised as a windmill. A nearby gun emplacement was connected to it through an underground bunker. The complex was captured by the Germans in the 1941 invasion. At the time, of course, there were far fewer trees.

Foxholes dug by defending German troops on top of Kaugatuma Cliff in November 1944. As you can see from the map above, the Soviet amphibious landing was successful. On November 24th, against a direct order from Adolf Hitler, the Germans evacuated the Sõrve Peninsula and thus the last part of Estonia they held. The Soviets reported that up to 7000 German soldiers had been killed on Saaremaa, Hiiumaa, and Muhu islands during their offensive.

Nick holds the rusted remains of a World War II artillery shell found near Sääre.

The museum we visited was filled with objects collected from the World War I and World War II battlefields on the Sõrve Peninsula. This shelf of bullet-riddled German helmets was particularly poignant. There was a similar shelf of Soviet helmets.

This is the text of a monument we found in the woods on the way to Sääre. It is the only such memorial I’ve seen here in all three languages of the combatants. (I could not find a way of editing out my own ghostly reflection.)

Without the old trenches, bunkers and decaying concrete fortifications, it would be hard to believe such violent events happened on these quiet islands. The occupations by the Nazis and Soviets had their own much more ghastly horrors as well, including mass executions, deportations and concentration camps. It is over now, though, and we can freely wander these beautiful shores and absorb ourselves in the arcane details of Silurian paleoecology while enjoying the flowers, butterflies and very friendly Estonian people. Here’s to peace and the vigilance to maintain it.

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