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Maine's geologic past is unknown prior to 650 million years ago, although some geologists have suggested that rocks over a billion years old may be present in units of the Chain Lakes in northwestern Maine. The state is made up of three distinct terranes, including Laurentia, Iapetus Ocean terranes and the former microcontinent of Avalonia.
The Ossipee Mountains contain substantial amounts of volcanic rock, and the many ring dikes across the region indicate that there was once an active volcano on the site. [9] [10] Volcanic rocks can also be found throughout the White Mountains beyond the Ossipee region, further confirming that eruptions occurred across the area millions of years ...
[3] [8] [10] The remainder of the pluton then cooled at a much faster rate for another 50 million years in another phase related to tectonic uplift. [ 8 ] [ 5 ] Although the Sebago Granite is igneous in origin, the muscovite present throughout the unit indicates some partial melting of surrounding sedimentary or metasedimentary rocks at some ...
On a map showing only metamorphic rocks, the Canadian Shield forms a circular pattern north of the Great Lakes around Hudson Bay.. The Canadian Shield is a large area of Archean through Proterozoic igneous and metamorphic rocks in eastern Canada and north central and northeastern United States.
The Salmon Falls River and the Piscataqua define the southern portion of the border with Maine. The largest of New Hampshire's lakes is Lake Winnipesaukee, which covers 71 square miles (184 km 2) in the east-central part of New Hampshire. Umbagog Lake along the Maine border, approximately 12.3 square miles (31.9 km 2), is a distant second.
It is bounded on the east by metamorphic and sedimentary rocks of the Piedmont Province. [16] The Adirondack and New England Provinces include sedimentary, meta-sedimentary, and plutonic igneous rocks, mainly of Cambrian and Ordovician age, similar lithologically to rocks in the Blue Ridge and Piedmont Provinces to the south. The uplifted ...
The qualifications for this list of Maine lakes is that the lake is located partially or entirely in Maine, named, and has a surface area of more than 10 acres (40,000 m 2). This makes it legally a great pond unless it is dammed, smaller than 10 acres (40,000 m 2 ) prior to damming, smaller than 30 acres (120,000 m 2 ) afterwards, and entirely ...
Short-lived rivers, lakes, and inland seas left sedimentary records of their passage. [11] One of the most geologically intriguing features of the Colorado Plateau is its remarkable stability. Relatively little rock deformation (e.g., faulting and folding) has affected this high, thick crustal block within the last 600 million years or so. In ...