Unlabeled

The San Juan River below Bluff, Utah: the age of the rock at the waterline

At Bluff the mapped rock at the waterline is about 177 million years old; 19 miles downstream, about 320 million. From mile 39 to 70, through the Goosenecks, it stays that old.

What does this axis measure?
What does this axis measure?
The San Juan River below Bluff, Utah: the age of the rock at the waterline: 14 points, a step line chart.
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Age of rock at waterline (million years)
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Distance downstream from Bluff (miles)
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The data: 14 points
Distance downstream from Bluff (miles)Age of rock at waterline (million years)
0177.1
3190.7
11237
12.1294.7
13298.9
14.1306
19319.7
24.1306
25.1298.9
32.1306
39.1319.7
71303.7
73.3298.9
87.1298.9
Source
USGS bedrock geologic map of the Bluff quadrangle and the Utah Geological Survey's Digital Geologic Map of Utah (via Macrostrat) along the USGS river network; periods from the ICS International Chronostratigraphic Chart (v2026-06); ages at the river calculated by Unlabeled
Licence
Public domain (USGS map, flowlines and GNIS place names); CC BY 4.0 (Macrostrat; ICS chart); ages at the river calculated by Unlabeled
Read
2026-11-04
Drawn
14 points as the puzzle showed them · step line
  • Ran in puzzle #41 on November 6, 2026. Play it