Wooster Geologists

KÄINA, ESTONIA–Today the Wooster/OSU team crossed the strait between Hiiumaa and Saaremaa to visit some earlier sites one last time on this trip. The Ohio State paleontologists stayed on the northern part of Saaremaa to look for crinoids and Panga, Ninase and Undva Cliffs; the Wooster geologists went farther south and west to visit Soeginina Pank (above) and Nick Fedorchuk’s 2011 field area. This was important to us so that we could compare observations here to Richa Ekka’s exposure of these beds on the eastern side of the island.

Richa stands by Nick’s Soeginina locality to compare it to her own rocks. This Soeginina section seems considerably more dolomitized in the west than the east.

Jonah and Richa at Nick’s outcrop. Richa is pointing to the Wenlock/Ludlow boundary horizon, and Jonah is showing the stromatolite layer near the top of the section. Richa’s section in the east begins somewhere above her finger.

We were impressed by how poorly preserved the stromatolites are in Nick’s section compared to the gorgeous specimens Richa studied earlier this week. You can barely make out the laminae in this western sample. Look here at its equivalent in the east.

Another difference we noted between the Richa and Nick sections was that Nick’s has thin coral branches (above) in storm layers whereas Richa’s does not. Nick’s oncoids are also larger and more complex.

The amount of damage the Soeginina Pank outcrop received in the last year is astonishing. I had worried about our hammer blows leaving noticeable marks on the rocks. The freshly fallen blocks on the cliff above appeared since our visit last June. Much of this is likely due to ice floes slamming into the rocks during the winter.

After our observations at Soeginina Pank, the Wooster geologists drove to Muhu to visit an historical site (more later on that), then went north through Orissaare to Triigi where we reunited with our OSU companions and boarded the ferry for the ride back to our hotel on Hiiumaa. Our two matching field vehicles are seen above at the front of the ferry. We weren’t going to miss the last ferry to the island!

KÄINA, ESTONIA–It was a beautiful Baltic day in the Hilliste Quarry on Hiiumaa. Thunderstorms swept by us to the east, but we stayed dry and enjoyed the quickly-changing cloudscape. The Wooster/OSU team was again studying the Hilliste Formation for both its crinoid content and general paleoecology. We did very well.

The typical limestone in the quarry is a biosparite/grainstone as seen above. The most common grains are bits of crinoid stems. The OSU team has found a few crinoid calices and calyx parts, but not as many as you would think given the enormous amount of crinoid skeletal debris in the unit.

It looks like a theme of this year’s Wooster study in the Hilliste Formation may be the sclerobiont (hard substrate-dwelling) fauna, especially the encrusters on corals, stromatoporoids and crinoid stems. Above you see an auloporid coral (the larger tubes connected at their bases) encrusting a favositid coral. Our other encrusters include crinoid holdfasts (three varieties), cornulitids (a kind of worm tube), sheet-like bryozoans, runner-like bryozoans (corynotrypids), and erect bryozoan holdfasts. As far as I know, no one has described a Rhuddanian sclerobiont fauna before.

We have our share of mysteries. Richa picked up the above coiled shell this morning. Bill and I have not seen anything like it in the Silurian before. If these were Jurassic rocks we would have called it a partial ammonite. We know it is not, but we don’t know what it is. A gastropod like Poleumita discors? A nautiloid cephalopod similar to Bickmorites? We’ll have to figure it out later in the lab.

Here is Jonah on the north quarry wall. We dress him brightly every day so we don’t lose him in the Estonian woods.

Richa is in her own world in the western part of the quarry looking for more paleontological treasures.

And finally, our Estonian animal of the day: a spider dutifully guarding her eggs in the quarry floor rubble. I suspect this is the Robust Crab Spider: Xysticus robustus (Hahn, 1832).
 

KÄINA, ESTONIA–The combined Wooster and Ohio State geology team left Saaremaa Island this morning and traveled to Hiiumaa Island to the north in our search for more Silurian outcrops and their associated fossils. We drove from Kuressaare to Triigi on the northern coast to catch a 9:30 a.m. ferry to Sõru on the southern coast of Hiiumaa. It was my second visit to this island. Like every other place in Europe, it has a long history. Settlement on Hiiumaa goes back to the Fourth Century BCE. For generations the island was known by its German name: Dagö. In recent times it has been Swedish, Russian, German, Estonian, Russian again, German again, and finally part of modern Estonia.

The main attraction for the Wooster Geologists on this trip is Hilliste Quarry (seen above) in the southeastern portion of Hiiumaa. The Lower Silurian (Rhuddanian) Hilliste Formation is exposed here — one of the few in this time interval worldwide. Jonah Novek will be starting his Independent Study project here, building on the labors of Rachel Matt last year. We are all continued to search for crinoids here as part of our joint work.

Jonah is seen here in his first few minutes of examining the Hilliste Formation in our little quarry. The rocks remind me of the Cincinnatian Series because they are a sequence of bioclastic and biomicritic limestones separated by thin beds of shale. This means fossils can be exquisitely preserved on the top and bottom surfaces of the limestones where they meet the soft shales.

An example are these trace fossils preserved on the underside (“sole”) of a biosparite limestone bed. These traces are in “convex hyporelief”, meaning that they stick out on the bottom of the bed. They were formed by deposit-feeding worms of some sort. We’ll have much more on the rocks and fossils of the Hilliste Formation in later posts.

After briefly visiting Hilliste Quarry (mainly a test to see if I really remembered how to get to it), we then traveled to the southeast coast of the island (the Sarve Peninsula) in the hope that we could find some exposures of Silurian limestones. There were tantalizing hints in the limestone shingle along the eastern shore and limestone slabs at the bottom of some roads, but there were many swamps and marshes.

Sometimes we had to use the giant glacial erratics to see above the trees, as Jeff Thompson is heroically demonstrating here.

We never did find additional exposures of bedrock. In the search, though, we saw many gorgeous vistas, like this one of a coastal marsh. (Note the excellent weather, by the way.) We will have several days to continue our quest for limestone on Hiiumaa.

Whenever you wander any distance in Estonia, you find reminders of its bloody and tragic 20th Century history. Rather than repeat the war stories, I’d like to end today with a happier image of a World War II pillbox enlivened by the joyful faces of Jonah and Richa!