The Tampico plate. Relief from Copernicus GLO-30; rivers and lakes from USGS NHD; watersheds from the USGS Watershed Boundary Dataset; roads and city limits from Census TIGER 2024.
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Tampico’s center stands about 2,140 ft above sea level. Within three miles the land runs from 1,920 ft to 3,740 ft, a difference of 1,820 ft: steep hill country. The highest named summit within 15 miles is Dome Peak, about 6,540 ft, 12 miles west-northwest.
Under the town center the state geologic map shows Miocene-Pliocene volcanic rocks (basalt), from the Early Eocene to Pliocene, 2.6 to 56 million years old.
The section below crosses 8 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 4×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Basalt. Age: Late Oligocene to Early Pliocene, 3.6 to 28 million years old. About 19 mi of the line.
Silt, sand. Age: Pleistocene, less than 2.6 million years old. About 1 mi of the line.
Silt, sand. Age: Holocene, less than 12,000 years old. About 0.9 mi of the line.
Sand, clay, silt. Age: Holocene, less than 12,000 years old. About 0.8 mi of the line.
Basalt. Age: Early Eocene to Pliocene, 2.6 to 56 million years old. About 0.7 mi of the line.
Fine-detrital, coarse-detrital. Age: Pleistocene, less than 2.6 million years old. About 0.7 mi of the line.
From the USGS State Geologic Map Compilation (Horton and others, 2017), the states’ geologic maps joined at a common scale. 2 smaller units along the line are not listed.
Heights from Copernicus GLO-90 (a surface model: it includes buildings and tree canopy); summits from USGS GNIS; rivers from USGS NHDPlus HR; rock from the USGS State Geologic Map Compilation.
A raindrop that lands in Tampico reaches the Pacific Ocean by way of North Fork Ahtanum Creek, Ahtanum Creek, the Yakima and the Columbia: about 460 river miles.
Lake on the way: Lake Umatilla.
210 miles of the trip are on the Columbia.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Tampico; river miles along the main stem, rounded.
