The Marietta 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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4.28 inches of rain fell in two days, the most for this week of the year since records began in 1947. The next wettest, 4.26 inches, fell in 2009.
Marietta’s center stands about 1,120 ft above sea level. Within three miles the land runs from 990 ft to 1,420 ft, a difference of 430 ft: hilly country. The highest named summit within 15 miles is Kennesaw Mountain, about 1,780 ft, 3 miles northwest.
The section below crosses 12 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 27×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Amphibolite, biotite-gneiss, mica-schist. Age: Precambrian to Paleozoic. About 5 mi of the line.
Biotite-gneiss, amphibolite. Age: Precambrian to Paleozoic. About 4 mi of the line.
Amphibolite, mica-schist, biotite-gneiss. Age: Precambrian to Paleozoic. About 4 mi of the line.
Biotite-gneiss. Age: Precambrian to Paleozoic. About 2 mi of the line.
Mica-schist. Age: Precambrian to Paleozoic. About 2 mi of the line.
Hornblende-gneiss, amphibolite. Age: Precambrian to Paleozoic. About 2 mi of the line.
From the USGS State Geologic Map Compilation (Horton and others, 2017), the states’ geologic maps joined at a common scale. 6 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 Marietta reaches the Gulf of America by way of Sope Creek, the Chattahoochee and the Apalachicola: about 420 river miles.
Lakes on the way: Walter F George Reservoir, West Point Lake and Bartletts Ferry Lake.
110 miles of the trip are on the Apalachicola.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Marietta; river miles along the main stem, rounded.
Marietta has a humid subtropical climate. Summer afternoons average 90° in July; winter nights fall to about 31° in January. About 54 inches of rain fall in a normal year, with about 4 inches of snow.
On November 14 Marietta normally reaches 64° and falls to 39°. The record high is 80°, in 1989; the record low 21°, in 1986. The most rain on this date, 2.31 in, fell in 1972.
Normals 1991–2020 and records since 1947 at Dallas 7 NE, 12 miles west-northwest. NOAA, through RCC-ACIS.
