Wooster Geologists

KURESSAARE, ESTONIA–The Wooster/OSU Estonia team continued to explore the Silurian section on Saaremaa Island today. It was our last day with our friend Olev Vinn, and he showed us the only remaining Silurian outcrop here I have not seen: Kübassaare Cliff in the far east of the island (N 58.43259°, E 023.30978°). The image above is the crew on the hike to the outcrop. I wanted to show some of the fantastic greens on this island as a break from the limestones!

Kübassaare Cliff exposes the Soeginina Beds of the Paadla Formation (lowermost Ludlow). Thjis was exciting for me because these are the same beds Nick Fedorchuk worked on last year during his Independent Study. The Kübassaare Clff exposures, though, are many kilometers to the east and show extensive bedding planes, enabling us to find many sedimentary and paleontological features not visible at Nick’s outcrop. You will read much more about this exposure tomorrow when we return to it for a full day of work. (Our explorations today were limited by the predictable downpour of rain.)

This is the trace fossil Chondrites on a bedding plane of the Soeginina beds at Kübassaare Cliff. These traces made by deposit-feeding worms are not common in shallow sequences like this, so there is a bit of a mystery here.

The stromatolites at Kübassaare Cliff are very well preserved and visible in all three dimensions (not just cross-sections in a cliff). They do not seem to have been dolomitized like many of those in the western exposure.

Kaali Crater is a site every geologist must visit while on Saaremaa. We stopped there on our trip back across the island.. I’ve been to the crater many times and so do not need to describe it here. It is an impressive place for the freshness of the crater walls in this very damp countryside.

During the Bronze Age there was a structure built around the crater walls. Whether it was a fort or some kind of religious enclosure is not known. I only noticed today that there are still the remnants of a very mossy stone wall on the periphery of the crater.

At the end of the day we returned to the southwestern coast of Saaremaa, on the Sõrve peninsula, to Kaugatuma, site of the crinoid-rich Äigu Beds (N 58.12449°, E 022.19446°). Bill and his students found some spectacular crinoid specimens, including new calices and a kind of holdfast I had not noticed before. The rain ended (mostly) and we were able to end our day rather leisurely examining this spectacular outcrop.

Tomorrow we split up for separate field localities. The Wooster geologists are returning to Kübassaare Cliff to measure and sample the section as the centerpiece of Richa’s Independent Study project; the OSU team is heading to the northern coast of Saaremaa to collect more crinoids from the Ninase Member of the Jaani Formation. We aready know it is going to rain!

KURESSAARE, ESTONIA–Bill Ausich (Ohio State University) and I have a grant from the National Geographic Society to study the “origination and evolution of Middle Paleozoic crinoids on the Baltica paleocontinent“. Bill is the prime mover behind this project as one of the world’s experts on crinoids, and probably the expert on Silurian crinoids. My job is to help with the paleoecology and stratigraphic context for these crinoids. We have one paper in press now on Estonian crinoids with our colleague Olev Vinn of the University of Tartu. The above photo shows our team this morning looking for crinoids in the Ninase Member of the Jaani Formation at the Undva Cliff on the northwestern tip of Saaremaa Island (N 58.51679°, E 021.91727°).

The full team includes Wooster students Jonah Novek and Richa Ekka (introduced before), Ohio State University graduate students Mark Peter and Alyssa Bancroft, and OSU undergraduate Jeff Thompson. Along with finding crinoids, the Wooster students will also be developing their Independent Study field projects. This is why our work is also supported by the Wengerd Fund at The College of Wooster.

Today we met Olev Vinn (and his wife Ingrid and two delightful children, Sigrid and Erik) and explored three outcrops looking for crinoids, especially their elusive calices (essentially their heads). Above is a calyx of Eucalyptocrinites showing partition plates. We found many more such beauties, especially at Undva Cliff.

Rain is going to be a fact of field life in the next week at least. The weather can apparently change rapidly on the Baltic coast. The above storm appeared to the west of us in mid-morning at Undva Cliff. Since the wind was blowing to the west, it didn’t seem an issue. The wind direction changed 180°, though, and quickly brought the deluge upon us. We ran back to our vehicles but were completely soaked. Lesson learned!

Our second outcrop was the Ninase Member again on the western shore of Tagalaht Bay at a place called Kuriku Cliff (N 58.50282, E 022.01284). You can see us above scattered along the cliff face.

The preservation of the fossils at Kuriku Cliff is mixed. Some calcitic forms are exquisite, especially brachiopods and crinoids. Others, like the favositid coral above, are recrystallized. In this case the corallites filled with calcite and then dissolved, leaving an odd kind of internal mold.

Our last outcrop was Kogula Quarry (N 58.28589°, E 022.26053°), where road gravel is made by progressively crushing limestones from the Silurian (Ludlow) Paadla Formation. Saturday was a good time to visit this quarry because it was closed and not operating. We found many fossils here, especially mollusks. The crinoids, though, were only rare bits and pieces.

Except for that morning drenching, it was a very good paleontological day. The Wooster students have been well introduced to Silurian limestones in general and Saaremaa stratigraphy in particular. Tomorrow we will see what Olev says is the only outcrop on Saaremaa I have not visited. That will complete our tour and we can then begin to do our detailed work. Now we know to run for cover as soon as we feel the wind quickly change!

KURESSAARE, ESTONIA–The 2012 Wooster Estonia expedition had its first official time in the field this afternoon. Jonah, Richa and I traveled the short distance from Kuressaare to the historical Sõrve peninsula in the extreme southwest of Saaremaa. There we explored the Äigu Beds in the Kaugatuma Formation exposed along the peninsula’s northwest coast. I know this place well from several visits, and it was the site of Palmer Shonk’s Independent Study project. The limestone here is mostly a high-energy encrinite (a rock made almost entirely of crinoid fragments) with many elaborate crinoid root systems in place showing the arrangement of a “crinoid forest”. Pictured above is a limestone bedding plane with two primary axes of the roots  (holdfast) of the genus Enallocrinus. The interior sediment has eroded away so that you can see the holes where “rootlets” emerged to penetrate the surrounding sediment.

Richa and Jonah on the swampy northwest side of the peninsula with the Kaugatuma Cliff exposed in the background.

Our liberally-educated students are here examining the surface of a granitic boulder brought here from Sweden by the last glaciation and dropped as an erratic. Of course, it is not the igneous rock that excites them — it’s the multicolored  lichens on it!

This project is funded by a grant from the National Geographic Society and the Wengerd Fund of The College of Wooster. Tomorrow we will introduce you to the Ohio State University team members and more details about our work and goals. We are very grateful for this research opportunity. We are also very pleased with the spectacular weather. Sunny and 26°C today.