ATCHAFALAYA BAY, 30 x 60 MINUTE GEOLOGIC QUADRANGLE SERIES 92°00' 45' 30' 15' 91°00' 29°30' 29°30' Hadp Hadp Hadp Description of Map Units Hadp ISLAND Htd South Point Htd Hadp Htd EAST COTE BLANCHE BAY QUATERNARY SYSTEM HOLOCENE

R Htd Mound Point E V Atchafalaya plain deposits—Deltaic deposits predominantly I Htd Hadp composed of distributary sand, delta-front and prodelta mud and clay, and natural R Hadp levee silt and clay. These sediments lie upon the surfaces of the Teche delta lobe. Hadp A Y Distributary complex of the Lafourche delta lobe—deltaic deposits A Hdl L underlying the delta plain of the Lafourche delta lobe. They are composed of FA cyclically interbedded interdistributary peat and clay; natural levee silt and clay; A distributary sand; and delta-front and prodelta mud and clay. H TC Deposits of the Teche delta lobe, —deltaic deposits A Hadp ER Htd underlying the delta plain of the Teche delta lobe. They are composed of cyclically W interbedded interdistributary peat and clay; natural levee silt and clay; distributary LO R E sand; and delta-front and prodelta mud and clay. These sediments lie upon the IV surfaces of the Maringouin and other older delta lobes, which are either buried Hadp R Hadp beneath younger delta lobes, submerged beneath the , or a combination of both, and upon the surface of the underlying Prairie Allogroup. Hadp Open water A T C Htd H A Tidal flats F A L A Shell Keys POIN Y T A A U FER Inferred contact S Htd HE LL

RE Streams and canals E B o F r A c Y n e Topographic contours e k r a a C L Bathymetric contours ST. MARY PARISH

South Point TERREBONNE PARISH

IBERIA PARISH IBERIA ST. MARY PARISH MARY ST. Hdl S tate rs The compilers gratefully acknowledge constructive technical review by L. D. Wate Fe Britsch and H. H. Roberts deral Waters FOURLEAGUE References;

Surface Geology Busch, R. E. Jr., W. C. Ward, and H. C. Skinner (compilers), 1974, Physiographic Lost Lake map of the Atchafalaya Basin and a portion of the Lower Red River Valley, Louisiana: U.S. Army Corps of Engineers, New Orleans, Louisiana, scale Hdl 1:250,000.

Point Hdl Engineer Agency for Resources Inventories, 1973, Inventory of basic Au Fer environmental data, south Louisiana, Mermentau River Basin to Chandeleur Sound, with special emphasis on the Atchafalaya Basin: Prepared for U.S. Army Hdl Corps of Engineers, New Orleans district. Hdl Hdl Hdl Louisiana Oil Spill Coordinator's Office, 2007, Landsat Thematic Mapper Satellite BAY Image 2005, UTM Zone 15 NAD83, LOSCO (2007) Hdl [landsat5tm_la_lsu_2005.sid]: Louisiana Oil Spill Coordinator's Office, Baton Ba Rouge, LA. yo u ck o May, J. R., L. D. Britsch, J. B. Dunbar, J. P. Rodriguez, and L. B. Wlosinski, m 1984, Geological investigation of the Mississippi River deltaic plain: U.S. Army a m H Corps of Engineers, Waterways Experiment Station, Vicksburg, Technical Report Hdl Hdl B l u e GL–84–15, prepared for U.S. Army Corps of Engineers, New Orleans district [unpaginated: oversized pages, including plates at 1:62,500 scale]. Hdl Hdl Saucier, R. T., 1994, Geomorphology and Quaternary geologic history of the Lower Mississippi Valley: volume 2, Vicksburg, Mississippi, U. S. Army Corps of Engineers, Waterways Experiment Station [unpaginated: 31 oversized pages, POINT AU FER ISLAND including 28 plates (1:250,000-scale)].

Saucier, R. T., and J. I. Snead (compilers), 1989, Quaternary geology of the Hdl Hdl Hdl Lower Mississippi Valley: in Morrison, R. B., ed., Quaternary non-glacial geology: p ST. MARY PARISH MARY ST. o conterminous : Boulder, Colorado, Geological Society of America, n TERREBONNE PARISH TERREBONNE u Hdl The Geology of North America, v. K-2, Plate 6, scale 1:1,100,000. J

15' 15' Smith, L. M., J. B. Dunbar, and L. D. Britsch, 1986, Geomorphological

Investigation of the Atchafalaya Basin, Area West, Atchafalaya Delta, and y Terrebonne Marsh: volume 2, Vicksburg, Mississippi, U. S. Army Corps of a Hdl Engineers, Waterways Experiment Station [unpaginated: 54 oversized plates B (1:24,000-scale)]. Hdl Hdl Van Lopik, J. R., 1955, Recent geology and geomorphic history of central coastal Louisiana: Unpublished PhD. dissertation, Louisiana State University, Baton Hdl Rouge, 195 p. Hdl Hdl New mapping by the compilers based in part on LIDAR quarter-quadrangle images (source: Louisiana Federal Emergency Management Agency, and U.S. Army Corps of Engineers, St. Louis District), and digital orthophoto quarter Hdl quadrangle images, downloaded from the Atlas website http://atlas.lsu.edu); and on the U.S. Department of Agriculture, Natural Resources Conservation Service Hdl (NRCS), Soil Survey Geographic (SSURGO) Database.

Hdl S Hdl tat e W Hdl Hdl Fed ate era rs C l W a Hdl at i er l s l o u

B a G y U L F

O F

M E X I C O

29°00' 29°00' 92°00' 45' 30' 15' 91°00' ATCHAFALAYA BAY, LOUISIANA 29091-A1-TB-100 o 94 o Produced and published by the Louisiana Geological Survey 92 90o 3079 Energy, Coast & Environment Building, Louisiana State University Baton Rouge, LA 70803 • 225/578-5320 • www.lgs.lsu.edu Kilometers 1 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Shreveport North Monroe North Bastrop Miles 1 0 1 2 3 4 5 6 7 8 9 10 11 12 13 Production of this map was supported by the U.S. Geological Survey, Shreveport South Monroe South Tallulah Department of the Interior, under Assistance Award No. G10AC00383. 32o Correlation of Map Units The views and conclusions contained in this document are those of the authors SCALE 1:100,000 and should not be interpreted as necessarily representing the official policies, Natchitoches Winnfield Natchez 0 50 miles Copyright ©2012 by the Louisiana Geological Survey either expressed or implied, of the U.S. Government or the state of Louisiana. 0 50 kilometers Base map from U.S. Geological Survey 1:100,000 Digital Line Graphs (100K DLG) 0o 46’ E Universal Transverse Mercator Projection, Zone 15 Teche Atchafalaya Lafourche Leesville Alexandria Woodville Lobe Lobe Lobe This map has been carefully prepared from the best existing sources available at North American Datum 1927 (NAD 27) Hapd the time of preparation. However, the Louisiana Geological Survey and Louisiana Geology by: Paul Heinrich and John Snead. Contour Interval 2 meters De Ridder Ville Platte New Roads Amite Bogalusa Hdl State University do not assume responsibility or liability for any reliance thereon. Bathymetric Interval 1 meter This information is provided with the understanding that it is not guaranteed to be National Geodetic Vertical Datum 1929 Lake Charles Crowley Baton Rouge Ponchatoula Gulfport correct or complete, and conclusions drawn from such data are the sole o GIS compilation by: R. Hampton Peele, Marcus B. Massom, and Katherine A. Renken 30 Holocene responsibility of the user. These regional geologic quadrangles are intended for APPROXIMATE MEAN DECLINATION, 2012 Port Arthur White Lake Morgan City New Orleans Black Bay use at the scale of 1:100,000. A detailed on-the-ground survey and analysis of a change = 0o 7’ west/year specific site may differ from these maps. Htd Chacko J. John Atchafalaya Terrebonne Mississippi Bay River Delta Cartography by: Robert L. Paulsell and Lisa G. . Bay Atchafalaya Bay 30 x 60 Minute Geologic Quadrangle Director & State Geologist 30 x 60 Minute Louisiana Geologic Quadrangle Index Published 2012 2012 Publication