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A Tapestry of Time and Terrain

posted by Jason Kottke   Nov 09, 2017

Tapestry Time Terrain

A Tapestry of Time and Terrain is a map from the USGS that shows the topology and ages of rock underneath the surface of the United States. The age scale on the right is difficult to read unless you download the full 45Mb PDF version, but it goes from Precambrian (2.6 billion years ago) at the bottom to more-or-less the present day at the top.

Through computer processing and enhancement, we have brought together two existing images of the lower 48 states of the United States (U.S.) 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 in separate formats. 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. This union of topographic texture with the patterns defined by units of geologic time creates a visual synthesis that has escaped most prior attempts to combine shaded relief with a second characteristic shown by color, commonly height above sea level (already implicit in the shaded relief). 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.

(via @robgmacfarlane)