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New Louisiana 30 by 60 Geologic Quadrangle Map Published

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  • Location:Baton Rouge, Louisiana
  • Interests:Quaternary geology, archaeological geology, geologic mapping, archaeology.
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The Louisiana Geological Survey has released the Amite Geologic Quadrangle map
authored by Richard McCulloh, Paul Heinrich and John Snead. Its scale is 1:100,000
and the map is 28 X 48". It is a multicolored map which describes and illustrates
the surficial geology of the Amite Quadrangle. Except for the Mississippi River Delta,
this map completes the 30 by 60 degree geologic map coverage of the coast-wise
portion of the Louisiana coastal plain underlain by Pleistocene and Holocene
sediments. More detail at:


PDF files of many of the published 30 by 60 degree geologic maps can be downloaded
from "maps" at:


Paper copies of the 30 by 60 degree geologic maps can be ordered from:



In time, the shapefiles of these maps, as they are proofed and the metadata is compiled,
will become available for downloading from a future web page.

While preparing the above maps, it was found that the terraces mapped by Harold N.
Fisk for the Williana and Bentley formations in the Rapides, LaSalle, and adjacent
parishes are completely imaginary; the Williana Formation, in addition to its terrace, is
a nonexistent stratigraphic unit; and there is a lack of any evidence for either the
existence of or the contact between the coast-wise portions of either the Bentley and
Montgomery formations as mapped by him, Holland, and associated researchers
within Southwest Louisiana. The Lissie (Early Pleistocene) and Willis (Pliocene)
formations have been reinstated within Southwest Louisiana.

One major problem was at the time that they did their geologic mapping, they had
only planimetric maps to use in their geologic mapping and barometric altimimeters,
often strapped to a car, as a source of elevation data for delineating extremely low relief
(very, very flat) and very gently gulfward dipping geomorphic surfaces. A number of the
terrace scarps that they mapped within Southwest Louisiana have been found to be
coast-wise fault-line scarp trends.

The 2008 version of the "Generalized Geologic Map of Louisiana" can be found on the
above web page or directly downloaded from:



A loess thickness map of Louisiana is also available from "Public Information Series" at:


http://www.lgs.lsu.e...s...p of LA.pdf

Reprints of papers concerning some of the research conducted for the above geologic
mapping can be found at;


Other papers and talks are still in preparation.



Paul V. Heinrich
Louisiana Geological Survey
Louisiana State University
Baton Rouge, LA 70803

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