PORT ARTHUR, TEXAS/LOUISIANA 30 x 60 MINUTE GEOLOGIC QUADRANGLE SERIES 94°00' 45' 30°00' 30' 93°00' u 15' u o Hsm yo u a y B yo a k Ppbe Ppbe 30°00' a B ac Pper G B r Bl Pper Hcm D r e a Description of Map Units Neches ig iv U Hackberry D n Pper Ppbe N d R Ppbe Pper Pper Ppbe d l Old River Cove O Sabine Hcm Canal Rycade Vincent Island U Hm Ppbe Island Ppbe s Pper Canal Ppbe River s Jubert a Hm L Pper P Point a k t Ppbe Hua e HOLOCENE Humble as Sweet Lake E Black Bayou Pper Ppbe Atreco Island s R e Grays i s s Ppbe d Holocene undifferentiated alluvium—undifferentiated deposits of small upland Port Neches k ou s u r Bay g a a Pper l o t e Willow Lake INTRACOASTAL WATERWAY Prong S U Hua o y Hua streams: alluvial deposits of minor streams and creeks, of varying textures, filling valleys a M Ppbe D B Ppbe Canal North incised into older deposits. Ditch Commissary Point Hm Ppbe Pirogue Hm Pper Small river meander-belt deposits—point-bar and associated overbank deposits ORANGE CO Starks North Canal JEFFERSON CO Starks North u East Ppbe No 1 Canal INTRACOASTAL Hsm underlying meander belts of the Sabine River. These deposits typically consist of gray to o y Fork a reddish brown sand, silt, silty clay, and sandy clay. Canal B U D L A No 2 Canal Ppbe Mermentau Alloformation—Complexly interfingering and interbedded, dark-colored N A s n Wild Cow Savane Neuville Island C Hm marine muds, sandy and shelly beach deposits, organic marsh clays, and lacustrine and e Right re Lake G bay muds. These deposits bury the surfaces of the Prairie and Deweyville Allogroups. The Ppbe No 3 Canal Ppbe Louisiana chenier plain forms the surface of the Mermentau Alloformation. The ORANGE CO Pines Ridge Sweet Lake Alloformation extends westward along the coast into Texas as far west as Galveston Bay. Sweet Lake Canal CAMERON PARISH Eastward, it extends almost to the west shore of Vermilion Bay, where it interfingers with Vincent deltaic sediments of the Teche delta lobe. Seaward of the shoreline, the Mermentau Lake Hm WATERWAY Alloformation grades laterally into unnamed marine sediments. Greens Hmr Blind Lake Lake Long Point e Holocene coastal ridges (cheniers)—Sandy and/or shelly ridges, of predominantly E Lost Lake Hmr Hm k coast-parallel orientation, delineated on portions of the surface of the Holocene Ridge S a Mermentau Alloformation. They comprise beach ridges separated from each other by E Hm e H n C K L i extensive tracts of coastal marsh. The areas mapped may include some ridges of other Hm r E r N you o Ba Bo C origin in places. Port Arthur is A Hm Boudreaux Pichot Ridge West Cove Canal Lake Ppbe L Ppbe Hm u Hog Island e i PLEISTOCENE s M angr a ove PRAIRIE ALLOGROUP Ba Ppbe Hmr yo Nort g Hmr c u h n l Pro a A diverse depositional sequence of late to middle Pleistocene deposits of the Mississippi Back Ridge River, its tributaries, and coastal plain streams; includes terraced, fluvial (meander-belt, Willow Bayou Canal C backswamp, and braided-stream), colluvial, estuarine, deltaic, and marine units deposited Canal ay B ou Starks Central Canal over a considerable part of the late Pleistocene (Wisconsin to Sangamon). Surfaces u o w ay generally show little dissection and are topographically higher than the Holocene units. lo B il Multiple levels are recognized along alluvial valleys and coast-parallel trends. The Prairie is W E Burton Sutton Canal divided into two temporal phases of deposition. Taylor B ayo Broussard u rth N o N East Lake Hm PRAIRIE ALLOGROUP, LATE SANGAMON—younger of the Prairie Allogroup temporal West Cove Cove I G ra B phases. Alluvial deposits of ancestral late Pleistocene streams. In the coast-parallel Prairie n d ay East ou West the unit consists of meander-belt deposits of the late Pleistocene Mississippi River, and B y Prong WATERWAY Beach Canal t d r Creole Port Authur l be deposits of the late Pleistocene coastal plain streams. Deposits associated with these Deep Bayou Canal u O Hm am o A TEXAS L ay Little valleys are commonly found within the upper portions of the drainage basins. Sediments Rabbit B Chenier Ridge at the top of the unit range from sand to clay. S LOUISIANA Island Hm S Hm o u PRAIRIE ALLOGROUP, EARLY SANGAMON— older of the Prairie Allogroup temporal t h Hmr phases. A diverse depositional sequence of flood plain, meander-belt, and backswamp Starks Hm South Canal P r J o deposits of the middle Pleistocene ancestral Mississippi River, Red River, local fluvial o n h g n CALCASIEU Magnolia Vacuum Canal Magnolia Vacuum equivalents of tributary streams, and coastal plain streams. The sediments are generally s U Big Hill o k r Hmr n Reservoir D o clay, silty clay loam, or sandy clay loam, but may include some sand and gravel in deposits ’ Hmr u F s o Hmr y St. Johns Islandt Ba Fork s a of relict channels. E High Island B a u West y o y —coastal plain deposits of late to middle Pleistocene o ep Beaumont Alloformation a u e B Madame Johnson’s D U u Hm e o Ppbe S k y streams; the oldest alloformation and topographically highest surface of the INTRACOASTAL a D a B Bayou Lake t Creole a L r e r t Prairie Allogroup units of southwestern Louisiana. s k y s th O SHIP r Hmr No Hmr Garrison Ridge Back Ridge Pumpkin Ridge relict Pleistocene coastal ridges—low-lying ridges delineated on the surface U d u Pper of the Beaumont Alloformation. Some of these ridges are coast-parallel and Round P Hmr O D M Lake R Johnsons Bayou others trend obliquely to the coast and radiate from the end of known meander T Old Landing Oyster Lake belts. Blue Buck E Hmr a Bay Cameron Hm st o Point u Hm A Hm Hmr R Monkey Island Lost T CAMERON PARISH Hmr U H Hmr Hmr Old ? Oak Grove Eugene Island Lake U JEFFERSON CO D Hm R Smith Hmr Eli Ridge Front Ridge Dans Ridge Ridge Hmr Hm K Canal ing CA s B Open Water N Hmr ayo AL Hmr Hm Oak Grove Ridge u Mud CHANNEL B Lake Sanders ayou Hamilton L Contact—includes inferred contacts. Mesquite aba Ridge Lake Hmr uv Mermen Point Hmr e tau r ive Fault—dashed where inferred; dotted where concealed; queried where indefinite. Hmr Garner Ridge R Johnsons Hmr Hmr L Bayou ow Streams Hmr C er Salt Work Ridge Garner Ridge A M 45' Hm ud L Roads Hackberry Ridge La C ke 45' Hm A S Hmr Topographic contours I E U Sabine Area uplifted by salt dome Wildcat Ridge Pass P Hm A S S Sabine u o Pole Bay Texa Lake s Louisiana Point Texas Point S A B I N E P A S S F M O E X I C O L F U G 29°30' 94°00' 45' 29°30' Cheniers represent new mapping by the compiler based on LIDAR 30' 15' 93°00' quarter-quadrangle images (source: Louisiana Federal Emergency Management Agency, and U.S. Army Corps of Engineers, St. Louis District), and digital orthophoto quarter quadrangle images (originator: Louisiana Oil Spill Coordinator's 94 92 Produced and published by the Louisiana Geological Survey 90 Office) . 3079 Energy, Coast & Environment Building, Louisiana State University Correlation of Map Units PORT ARTHUR, TEXAS/LOUISIANA 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 29093-F1-TM – 100K Copyright ©2005 by the Louisiana Geological Survey Miles 1 0 1 2 3 4 5 6 7 8 9 10 11 12 13 coastal plain L O U I S I A N A Geology by: Paul V. Heinrich 32 SCALE 1:100,000 0 50 miles Hmr Base map from U.S. Geological Survey 1:100,000 Digital Line Graphs (100K DLG) GIS compilation by: R. Hampton Peele and Prammagnaanam Vijaiamernath Hsm Hua Hm Universal Transverse Mercator Projection, Zone 15 Cartography by: John Snead and Lisa Pond North American Datum 1927 (NAD 27) The views and conclusions contained in this document are those of the authors and Contour Interval 2 meters should not be interpreted as necessarily representing the official policies, either De Ridder Ville Platte New Roads Amite Bogalusa National Geodetic Vertical Datum 1929 Pper expressed or implied, of the U.S. Government or the state of Louisiana. Lake Charles Crowley Baton Rouge Ponchatoula Gulfport Ppbe 30 This map has been carefully prepared from the best existing sources available at the time of preparation. However, the Louisiana Geological Survey and Louisiana State Port Arthur White Lake Holocene Pleistocene University do not assume responsibility or liability for any reliance thereon. This 1934 information is provided with the understanding that it is not guaranteed to be correct Port Arthur 30 x 60 Minute Geologic Quadrangle or complete, and conclusions drawn from such data are the sole responsibility of the Chacko J. John user. These regional geologic quadrangles are intended for use at the scale of 30 x 60 Minute Geologic Quadrangles 1:100,000. A detailed on-the-ground survey and analysis of a specific site may differ Published (2005) 2005 Director & State Geologist from these maps.