The Tangipahoa 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.
Tangipahoa’s center stands about 190 ft above sea level. Within three miles the land runs from 140 ft to 280 ft, a difference of 140 ft: gently rolling country.
Under the town center the state geologic map shows Alluvium (clay), from the Holocene, less than 12,000 years old.
The section below crosses 4 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 64×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Clay. Age: Holocene, less than 12,000 years old. About 12 mi of the line.
Clay, silt, sand. Age: Pleistocene, less than 2.6 million years old. About 6 mi of the line.
Sand, gravel. Age: Pliocene to Pleistocene, less than 5.3 million years old. About 4 mi of the line.
Clay, silt, sand. Age: Pleistocene, less than 2.6 million years old. About 3 mi of the line.
From the USGS State Geologic Map Compilation (Horton and others, 2017), the states’ geologic maps joined at a common scale.
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 Tangipahoa reaches Lake Pontchartrain and the Gulf of America by way of the Tangipahoa: about 60 river miles.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Tangipahoa; river miles along the main stem, rounded.