Boat Tours & Sea Cliffs

KILFENORA, IRELAND – We continued our exploration of the geology of County Clare on Wednesday morning with a boat trip in the Shannon Estuary. We departed from the docks at Carrigaholt and proceeded by boat out of the harbor (built in the 14th century) and passed an interesting historical convergence: the wreck of a WWII liberty ship, which was lying at the foot of a fort built to defend against a Napoleonic invasion that never came, at the foot of a hill topped by the ruins of a 6th century church. The amount of history here is simply overwhelming. We spent the rest of the morning using the boat to take a closer look at fantastic sea cliff exposures of the Ross Formation along the south side of the Loop Head Peninsula. This sequence of interbedded sandstone and shale was deposited as a series of turbidity flows into a basin. Later in the evening, Michael Fortwengler (Shell Exploration & Production) taught the group how to calculate a STOIIP (Stock Tank Oil Initially In Place) estimate for a sequence like the one we had observed in the sea cliffs. STOIIP estimates allow geologists to calculate how much oil can be recovered from a reservoir… and provides a basis for determining if producing a new reservoir makes economic sense.

In the afternoon, we followed a group of dolphins back to the dock at Carrigaholt and then traveled southeast on the Loop Head Peninsula to the village of Kilbaha, where the group ate lunch and took advantage of some amazingly soft grass for a quick nap. We then took another look at the Ross Formation exposed along Kilbaha Bay. These exposures also contained a very interesting contact with overlying glacial deposits – in several places is was possible to see chunks of Ross Formation sandstone literally being ripped off the outcrop and rolled into the overlying glacial material.

On Thursday, we returned to Ross Bridge and explored the East side of the bay. Dr. Best took us to a location atop the massive submarine slide deposit we had visited earlier in the week to examine some impressive sedimentary structures, including some amazingly well preserved sand volcanoes that formed when pore fluid from inside the slide was expelled after it stopped moving. Later that evening the students worked on daily summaries in their field notebooks while Mary and Drew treated everyone to an impromptu guitar and mandolin concert. The locals loved it! The owner of the Kilfenora Hostel, Orla, ended the evening by singing her rendition of a beautiful traditional Irish song.

Friday brought us a little further north in County Clare, near the village of Trusklieve, where we examined a series of exposures of the Gull Island Formation and a series of five cyclothem deposits in the region. These sea cliff exposures are located along an stunningly beautiful section of the coastline just southwest of Kilkee.


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