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Geologic Map
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Topographic Map
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| Through computer processing and enhancement,
we have brought together two existing images of the Nation's lower
48 states into a single digital tapestry. Woven into the fabric
of this new map are data from previous U.S. Geological Survey (USGS)
maps that depict the topography and geology of the United States.
The resulting composite is the most detailed and accurate portrait
of the U.S. land surface and the ages of its underlying rock formations
yet displayed in the same image. The new map resembles traditional
3-D perspective drawings of landscapes with the addition of a fourth
dimension, geologic time, which is shown in color. In mutually enhancing
the landscape and its underlying temporal structure, this digital
tapestry outlines the geologic story of continental collision and
break-up, mountain-building, river erosion and deposition, ice-cap
glaciation, volcanism, and other events and processes that have
shaped the region over the last 2.6 billion years. |
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