Monday, March 14, 2011

Rock Age in Connecticut

The oldest rocks are located in Northwestern Connecticut. Specifically from Salisbury to Colebrook and then down to Ridgefield and Redding. These rocks are metamorphic rocks and formed 1.1 billion years ago when supercontinent Rodinia assembles. The youngest rocks are in Central Connecticut. These rocks are igneous and sedimentary rocks. Water and volcanoes erupting mostly caused these types of rocks. About 250-200 Million years ago, the ice age begins and the ice sheets start to expand and create moving wall of ice called glaciers. Also, A rift valley forms in Central Connecticut as Pangea breaks apart and basalt erupts. The events that formed the rocks in Connecticut were volcanoes(igneous rocks) when a rift valley forms in the middle of Connecticut and basalt erupts, When converging contintinental boundries collides they brung metamorphic rocks, and lastly the sinking of the ocean floor caused sedimentary rocks to form. That's all I have to say about the rock age in CT.

Rock Types in CT

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 There are three main types of rocks in CT.  Metamorphic, igneous, and sedimentary. The most common rock found in CT is the metamorphic due to the collision of rodinia. You find metamorphic rocks on the coastline as well and in the eastern and western parts of CT. You can find igneous rocks in the center of CT which tells us that there were rivers or volcanos there. In the middle of CT you can also find sedimentary rocks. Sedimentary rocks are the second most common rocks found CT and that makes igneous the least most common rock found in CT. The rock types that are found in Greenwich are metamorphic.