After viewing six geo-sites in the past week, it seemed as if we were in the swing of things geologically speaking. But what now? Fortunately, we can tell our secret - we have been to all of the New England geo-sites except Rhode Island's. Today being a bright, sunny day, and since we are only about 10 miles away, we decided to visit Beavertail Point, at the southern end of Conanicut Island (Jamestown). All these years we have lived in Rhode Island we have never been to Beavertail Point; it is gorgeous and is Rhode Island's geo-site.
All of Rhode Island is part of the Avalon Terrane, a rock formation that originated as a volcanic island arc situated off Gondwanaland, the forebear of today's continents of Africa, South America, and Antarctica. The Avalon Terrane eventually broke away from Gondwanaland, becoming a drifting micro-continent. During the late Silurian time, the Avalon terrane collided with Laurentia adding to the real estate of this early stage of North America.
Then during middle Permian time, when Laurentia and Gondwanaland were tectonically welded together as part of the great supercontinent Pangaea, the Appalachian Mountains lay centrally imbedded in this "one Earth" landmass that stretched from the south pole to the north pole. By the time the dust of this mountain building collision had settled, folding and faulting had compressed -- by as much as 50% -- the now coast of New England and the resulting accordion effect created a mountain range that rivaled the height and beauty of today's Himalayas. After Pangaea fragmented during the Mesozoic era, the Appalachian Mountains assumed their position as a prominent coastal range.
The Avalon terrane structure is exposed at Beavertail Point. The juxtaposition of light and dark metamorphic rock identifies the fault that slices beneath the old lighthouse foundation, evidence of compressional forces so profound that massive degrees of fracture were the result.
The "new" granite light tower was constructed in 1856.
The foundation of the original Beavertail Lighthouse, erected in 1749, the third lighthouse to be established on the Atlantic coast.
The Beavertail Fault divides black-hued phyllite (a metamorphic rock) of the Dutch Island Harbor Formation (on the right) from light green to buff-colored phyllite of the Jamestown Formation.
Mr. Spock examining the folded rock formations.
This fold at Beavertail Point is representative of the landscape of contorted and disturbed rock that characterizes the Avalon terrane.
The new lighthouse behind the original foundation of Beavertail's 1749 lighthouse. Until recently, it was believed that first light tower was circular in shape. However, a 2008 ground penetrating radar survey determined that it was octagonal. Made of wood, that tower burned down in 1753. A stone tower was built on the foundation in 1753. In 1779, the British burned the tower as they departed Rhode Island and removed some of the lighting equipment.
I wouldn't want to be standing in front of this fog signal building when the alarm goes off.
We also passed this 1789 windmill on Jamestown Island.
