CompuServe Thread

Hi, Dan– I am posting a copy of your message in the geology section, to better attract the attention of those who might best know the answer. Replies to it will appear as replies to me rather than you, so be sure to read the whole "Maine islands" topic there. –Doug

Hi Different Maine islands probably have somewhat different origins. The entire area was actually quite flat in the Miocene, and I don't think that they were part of the chain of mountains resulting from continental drift that was described, although some of the terrain may be affected by this. What you see around much of the coast is sedimentary rock that may be related to the tectonics you described, schists that are metamorphosed deeper sedimentary rock (usually beneath the sedementary rock I just mentioned) and numerous granitic and basaltic intrustions. The granitic intrustion form the rounded islands in most places, the intervening areas eroded away by numerous trangressions and regressions of the sealine. Here and there are, I think, volcanics as well. Most of the islands, then, are hard bits intruded from below into softer rock, which have been exposed through erosion. More recently, i.e., the late Pleistocene, they have obtained their particular shape from glaciers running over them. Notice, for example, that the northerly sides of many of these islands are at a low angle while the sourtherly sides have more cliffs, and the islands tend to be elongated a bit north-northwest to south-southeast. The elongation is from the direction of the glacial movement, and the cliffs to the southerly side is from the "plucking" of hunks of granite and stuff by the glaciers moving over them. Hope this helps a bit! You can get some great geology info from the National Park in Adacia. Cheers, GTL – Greg Laden, Written 18-Oct-1994 @ 17:17:29 Using: Windows NavCIS PRO 1.25

You probably figured out Greg's typo refers to Acadia Nat'l Park. If not, knowing how to spell it should help you get some information from them!