NASA Earth Observatory image by Jesse Allen, using data from NASA/GSFC/METI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team. The most logical explanation for this would be a change in ice flow direction due to shifting ice divides.” “This would suggest that re-molding of pre-existing relief has taken place at some point. “Although the islands in the bay are more or less isolated landforms.some of the features further inland (north and northwest of Westport) seem to have merged and coalesced into elongated kilometer-long ridges, some even displaying curved or ‘hooked’ ends,” Hiemstra wrote in an email. Underneath the drumlins lie moraines: large, corrugated ridges that aligned at right angles under the ice flow.īut scientist John Hiemstra, a professor at Swansea University in the U.K., has a different theory. The biggest, Clare Island, guards the entrance to the sheltered bay and is home to 130 people. It’s probably the most beautiful bay in Ireland, and the views of it from all around Westport are spectacular. Twenty years ago, his work began to indicate that drumlins are merely the youngest part of a marbled landscape under the water surface. Clew Bay has, according to tradition, 365 islands, one for every day of the year. Knight’s research suggests that many of the hills may belong to another type of glacial landform-a rolling feature called a ribbed moraine. The Antrim coast that surrounds the ruins of Dunluce Castle Photos via Shutterstock 29. The windy road at Glengesh Pass in Donegal Photos via Shutterstock 28. The magical Kylemore Abbey in Connemara Photos via Shutterstock 27. Several theories exist about the formation of these drumlins. The view out over Clew Bay is just out of this world. “Sediments in Clew Bay suggest that were formed very quickly during a period of ice re-advance, when the glacier was hopping on and off the sediment bed, causing changes in water pressure,” Knight said. Sediment deposits indicate that the drumlins in Clew Bay were formed in quick bursts, instead of a slow process of ice creeping inch by inch. : Co Mayo Ireland Evening View Across Clew Bay To Croagh Patrick Poster. “Previous ideas of slow, steady advance or retreat really don’t hold. “Increasingly, we’re seeing that glaciers are really complicated,” said Jasper Knight, a geoscientist at the University of Witwatersrand (South Africa). Recently, the study of drumlins has helped scientists better understand how glaciers have shaped many existing landforms. There are 365 of them-one for every day of the year, according to local folklore. The word drumlin comes from the Gaelic word “druim,” meaning “back” or “ridge.”Ĭlew Bay’s drumlins peek out from underneath the water like the tips of icebergs. They are typically oblong, two or three times longer than they are wide. These islands in western Ireland date back 20,000 years, to a time when much of Ireland was covered by an ice sheet.ĭrumlins are elongated, teardrop-shaped hills of rock, sand, and gravel that form from the movement of glaciers, according to the National Snow and Ice Center. Islands spatter Clew Bay like the spots on a cow. Editor’s Note: Today’s caption is the answer to Earth Observatory’s August Puzzler.
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