Fault-line Scarps Of Southwest Louisiana

© 2006 by The Gulf Coast Association of Geological Societies

4

Distribution and Origin of Fault-Line Scarps of Southwest Louisiana, USA

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

Abstract Compilation of fault-line scarps and traces from existing geologic mapping and revision of the resulting compilation using remote sensing data and various aerial images revealed a complex pattern of Quaternary fault-line scarps within southwest Louisiana. Numerous, generally eastwest trending, fault-line scarps form a 24 km wide east-west trending belt lying south of a line between Ville Platte, Louisiana and Kirbyville, Texas. The southern edge of it is marked by a relatively continuous set of fault-line scarps associated with the Tepetate fault zone. Numerous faultline scarps occur between the Tepetate fault zone and the shoreline of the Gulf of Mexico. However, these fault-line scarps lack any regional pattern, and many are associated with local salt domes and growth faults. The northernmost fault-line scarps found within southwest Louisiana consist of a narrow belt of prominent east-west trending scarps within southern Rapides Parish. Many of these Quaternary fault-line scarps are the surface expressions of known Tertiary growth faults, a number of which are associated with roll-over structures containing oil and gas fields. Such oil and gas fields were formed as the result of reactivation of the faults during the Pleistocene. The reactivation of these faults and the associated formation of these scarps represent the results of the loading of the Gulf of Mexico margin starting in Late Pliocene time. This loading has had the effect of reactivating regional fault trends such as the Tepetate fault zone and causing the renewed flowage of deep-seated salt.

Introduction Southwest Louisiana consists of a series coastal terraces underlain by Pleistocene allostratographic units, which the Louisiana Geological Survey has grouped into the Intermediate and Praire allogroups (Fig. 1). A deeply dissected strip of Pliocene coastal plain sediments of the Willis Formation lies along the northern edge of the Pleistocene terraces between the Sabine and Calcasieu rivers. Between the Calcasieu River and the eastern valley wall of the Mississippi Alluvial Valley, younger Pleistocene sediments cover the eroded edge of these Pliocene age sediments (Heinrich and Autin 2000, Snead et al., 2002a, 2002b, McCulloh and Heinrich 2002, Heinrich et al., 2002, 2003, McCulloh et al., 2003). Within southwest Louisiana, the coast-parallel units comprising the Intermediate Allogroup, in order of descending elevation and decreasing age, consist of the Lissie, Elizabeth, and Oakdale alloformations. These alloformations consist of early to middle Pleistocene fluvial deposits of the Calcasieu, Mississippi, Sabine, and Red rivers, their tributaries, and coastal plain streams. Alloformations have relatively flat, but highly dissected, terrace surfaces lacking any remnants of original constructional topography. Intermediate Alloformation is bounded updip by the Willis and Fleming formations and onlapped gulfward by the sediments of the Prairie Allogroup. Near the Mississippi River flood plain, Sicily Island and Peoria loesses blanket the Intermediate Allogroup (Snead et al., 2002a, 2002b, McCulloh et al., 2003). Along the Red River and between it and the Mississippi River, the Intermediate Allogroup consists of the Pleistocene fluvial sediments of Fisk's (1948) Montgomery and Bentley formations (McCulloh and Heinrich 2004). Gulf Coast Association of Geological Societies Transactions, Volume 55, 2005

284 

Heinrich

4 3 7

Figure 1. Geologic map of southwest Louisiana showing known fault traces and fault-line scarps. Compiled and generalized from McCulloh and Heinrich (2002), Saucier and Snead (1989), and various published and unpublished 1:100,000 scale Louisiana geologic quadrangles cited in text. Note: ch = China segment, C = Cameron Meadows salt dome, H = Hackberry salt dome, J =Jefferson Island salt dome, Je = Jennings salt dome, mb = Marsh Bayou segment, t = Topsy segment, and V = Vinton salt dome.

k 285 

Distribution and Origin of Fault-Line Scarps of Southwest Louisiana, USA

4 3 7

The Beaumont Alloformation consists of Sangamon coastal plain deposits. A diverse assemblage of fluvial and deltaic sediments of the Calcasieu, Mississippi, Sabine, and Red rivers, their tributaries, and coastal plain streams; barrier sands that comprise Houston ridge; and estuarine and marine sediments comprise this alloformation. Unlike the alloformations that compose the Intermediate Allogroup, the surface of the Beaumont Alloformation, although degraded by various surficial processes, exhibits recognizable constructional landforms including coastal ridges, relict channels, and a barrier island ridge. It is onlapped gulfward by Holocene sediments of the Mermantau Alloformation. The Avoyelles Alloformation occurs as isolated terrace fragments and comprises the southeast corner of the Prairie Allogroup along the western valley wall of the Mississippi Alluvial Valley. Its surface exhibits the relict meander-belt morphology of the relict Lafayette meander-belt of the Mississippi River. The Big Cane Alloformation consists of Red River sediments intermediate in age, stratigraphy, and elevation between the Avoyelles Alloformation and modern Mississippi River floodplain. Peoria loess covers the surfaces of the Avoyelles and Big Cane alloformations and the western part of the Beaumont Alloformation adjacent to the Mississippi River Alluvial Valley (Heinrich and Autin 2000, Heinrich et al., 2002, 2003, McCulloh et al., 2003, McCulloh and Heinrich 2004). The Deweyville Allogroup consists of Wisconsinan fluvial deposits intermediate in age and stratigraphic position between Holocene fluvial sediments underlying the modern floodplains of the Calcasieu and Sabine rivers and the Prairie Allogroup. The surface of the Deweyville exhibits well-preserved meander scars that are substantially larger than those of adjacent modern flood plains. Gulfward, these surfaces dip beneath the floodplains and sediments of the river valleys along which they are found. Multiple units of alloformation rank have been recognized and mapped within the Deweyville Allogroup (Blum et al., 1995, Heinrich et al., 2002, 2003). For this paper, the alluvial valleys of the Calcasieu, Mississippi, Sabine, and Red rivers and their tributaries, the fluvial sediments underlying them are left undifferentiated. Within the Mississippi River Alluvial Valley, unnamed Pleistocene valley train deposits occur, which are also not discussed. The remainder of the Holocene sediment consists of the deposits of the Mississippi River delta and the Mermentau Alloformation. The Mermentau Alloformation, originally defined as the "Mermentau Member" by Jones et al., (1954), underlies the chenier plain of southwest Louisiana. It consists of dark-colored marine muds, sandy and shelly beach deposits, organic marsh clays, and lacustrine and bay muds that underlie the Louisiana chenier plain. This alloformation extends westward along the coast of the Gulf of Mexico into Texas as far west as Galveston Bay and eastward to Vermilion Bay (Jackson et al., 1954, Heinrich in press, in preparation). As discussed by Heinrich (2005), Howe and Moresi (1931) mapped the first fault-line scarp within southwest Louisiana. They interpreted this scarp to be a terrace boundary between their Pensacola and Hammond terraces. Later, Bernard (1950) was apparently the first person to recognize the presence of fault-line scarps within the southwest Louisiana region by mapping fault-line scarps just across the Sabine River in Texas within Newton County. Later, Heinrich (1988) postulated that a scarp, the Dequincy scarp, within southwest Louisiana interpreted by Fisk (1948) to be a terrace scarp, was, in fact, tectonic in origin. As reported by Heinrich (1997, 2000), the tectonic origin of one of these scarps, the De Quincy scarp, was confirmed by STATEMAP funded drilling conducted for Snead et al., (1995). Since then, fault-line scarps within southwest Louisiana have been mapped for and illustrated by several 1:100,000 scale geologic quadrangles, i.e. Heinrich and Autin (2000), Snead et al., (2002a, 2002b), Heinrich et al., (2002, 2003), and Heinrich (in press, in preparation). In addition, McCulloh et al., (2003) briefly described these fault-line scarps.

Methodology A map of fault-line scarps within southwest Louisiana was compiled from existing geologic maps and from new mapping created from recently available remote sensing data. The remote sensing data consisted of digital elevation models (DEMs) prepared from LIDAR (LIght Detection And Ranging) data available at Atlas: The Louisiana Statewide GIS at http://atlas.lsu.edu/ and National Elevation Dataset (NED) available at http://seamless.usgs.gov/. Previously mapped fault-line scarps were obtained from Heinrich and Autin (2000), Snead et al., (2002a, 2002b), Heinrich et al., (2002, 2003), 286 

Heinrich

4

Heinrich (2005), and Heinrich (in press, in preparation). The locations of these fault-line scarps as indicated on original draft 1:24,000 geologic maps for these sources were consulted and reviewed against LIDAR images produced using MacDEM, Version 1.0. In addition, analyses of the LIDAR DEMs using Global Mapper, Version 5.07, and visual inspection of MacDEM LIDAR images were used to map the location of additional fault-line scarps. The locations of these potential fault-line scarps were examined relative to features identifiable from USGS Digital Orthophoto Quarter Quadrangles, soils surveys, and available subsurface data. The height of fault-line scarps was estimated using Global Mapper, Version 5.07 from the LIDAR DEMs.

3 7 Results

Compilation and review of previously mapped fault traces and fault-line scarps and analysis of images produced from both LIDAR and NED DEMs revealed a number of previously unmapped fault traces and fault-line scarps. The plotting of these features on 1;100,000 scale topographic and geologic maps revealed three major regions of surface faulting. They are the Glenmora trend, Tepetate trend, and Southern Fault-line Scarps and Traces region.

Glenmora trend The northernmost set of fault-line scarps, the Glenmora trend, lies within southern Rapides Parish (Fig. 1). This trend consists of sets of east-west scarps, which lie within an area extending from just over a mile north of Lake Cocodrie westward past Glenmora, Louisiana, to the Rapides-Vernon parish line. Indistinct linear features on images made from LIDAR DEMs suggested the presence of the trace of another east-west fault trace lying about a mile south of the Allen-Rapides parish line. Because of the dissected nature of the terraces associated with the Lissie and Oakdale alloformations of the Intermediate Allogroup, it is difficult to determine the exact amount that the fault-line scarps of the Glenmora trend have displaced the terrace surfaces. For the northernmost sets of scarps, height varies from 15 to 25 ft (4.6 to 7.6 m). The westernmost scarp segment of one set has a height varying from 30 to 35 ft (9.1 to 11 m). The southernmost set of scarps has a height of only 8 to 10 ft (2.4 to 3.0 m). Available log data from water, oil, and gas wells is insufficient to confirm the presence faults associated with these scarps in the subsurface at this time. However, the morphology of these scarps, their east-west orientation, and their cross-cutting of terrace scarps separating the surfaces of the the Lissie and Oakdale alloformations clearly show them to be fault-line scarps. One scarp segment, which extends from the Lissie Alloformation across terraces of Tenmile Creek as a 3 ft (0.9 m) high scarp within southwest Rapides Parish, Sec. 31, T. 1 S., R.4 W. (Fig. 2). This and similar fault-line scarps within the Glenmora trend demonstrate the tectonic origin of these scarps and ongoing fault movement. At this time there appears to be a gap of about 23 mi (37 km) separating the Glenmora and Tepetate trends. A review of images made from NED DEMS, selected 1:24,000 scale topographic maps, and selected 1:24000 scale USGS Digital Orthophoto Quadrangles (DOQQ) revealed no evidence of significant scarps within this gap. Detailed analysis of LIDAR data, when it becomes available, might reveal scarps with heights below the resolution of the 1:24,000 scale topographic maps within this gap. Similarly with the currently available data, i.e. various aerial imagery and photographs, 1:24,000 scale topographic maps, 1:24,000 scale DOQQs, and DEMs derived from these topographic maps, no evidence of fault-line scarps west of the Rapides-Vernon parish line could be discerned. However, the detailed analysis of LIDAR data, when it becomes available, would be able to determine if the Glenmora trend extends further west. 287 

Distribution and Origin of Fault-Line Scarps of Southwest Louisiana, USA

4 3 7

Figure 2. Image produced from LIDAR DEM for the Steep Gulley 1:24,000 quadrangle showing fault-line scarp within the Glenmora trend. Arrows point to base of fault-line scarp. A = fault-line scarp cutting surface of Lissie Alloformation. B and C = scarp cutting terraces within the valley of Tenmile Creek within southwest Rapides Parish.

k

Tepetate trend Extending from the western valley wall of the Mississippi River alluvial Valley to the valley of the Sabine River, the Tepetate trend of fault-line scarps crosses across the surface of the Lissie and Beaumont alloformations westward into East Texas (Fig. 1). It consists of a 15 mi (24 km) wide zone containing several fault-line scarps. Except along its southern edge, the fault-line scarps that compose this trend apparently consist of discontinuous east-west scarps ranging from less than 1 mile (0.6 km) to about 7 mi (11 km) in length. However, when LIDAR data become available for this part of Louisiana covering the bulk of the Tepetate trend, it is possible that more fault-line scarps will be found and known ones will be found to be more continuous and extensive than can be determined using the data now available. The southern edge of the Tepetate trend is defined by an almost continuous series of fault-line scarps composed of four segments, the De Quincy, Marsh Bayou, Topsy, and China segments (Fig. 1). The De Quincy, Topsy, and China segments consist of gulfward-facing fault-line scarps. In contrast the Marsh Bayou segment consists of an inland-facing fault-line scarp. Where these fault-line scarps of the De Quincy and Topsy segments cross the Lissie Alloformation, they displace its surface by 25 to 30 ft (7.6 to 9 m) (Fig. 2). These fault-line scarps also displaced alluvium within the valleys, where they cross them. Further west, fault-line scarps of the China segment displace the surface of the Beaumont Alloformation between 6 to 10 ft (1.8 to 3 m) within Acadia, Jefferson Davis, and Lafayette parishes. Near the Acadia-Jefferson Davis parish line, fault-line scarp within the China segment, displaces a terrace, possibly belonging to the Avoyelles Alloformation, along Bayou Nezpique by about 4 ft (1.2 m). The faultline scarps of the China segment also displace several relict Pleistocene fluvial channels of the Red River. 288 

Heinrich

4 3 7

The fault-line scarps of the Tepetate trend are clearly associated with regional growth faults in the subsurface. As discussed in detail by Heinrich (2000) and Miller and Heinrich (2003), the fault-line scarps of the De Quincy and China segments are clearly associated with the Tepetate fault zone in the subsurface. Paine (1962) illustrated faulted alluvium of the Beaumont Alloformation exposed in the Wolfe gravel pit at Indian Village, Jefferson Davis Parish, Louisiana. Heinrich (2000) documented subsurface displacement of the alluvium comproing the Lissie Alloformation associated with a fault-line scarp of the De Quincy segment. The other fault-line scarps within the Tepetate trend are associated with regional growth faults as mapped by Lautier (1980, 1981), Lemoine (1989), Anonymous (2002), and others. Oil and gas fields associated with roll-over structures are often located immediately south of fault-line scarps within the Tepetate trend (Holland et al., 1952, Paine 1962, Standfield et al., 1981, Anonymous 2002, Miller and Heinrich 2003). Clear evidence of recent movement along fault-line scarps within the Tepetate trend exists within southwest Louisiana. As illustrated by Miller and Heinrich (2003), subsidence has occurred where a fault-line scarp of the China segment crosses a few floodplains of modern bayous and streams within Allen Parish. For example, the floodplain of Bayou Serpent has been offset by almost 3 ft (1 m). Heinrich (2000) found displacement of terrace surfaces within stream valleys where they cross the trace of the De Quincy segment in Calcasieu and Beauregard parishes. Images prepared from LIDAR data show that the Holocene floodplains of many of the drainages crossing the De Quincy segment are offset by low, but distinct, fault-line scarps (Fig. 3).

Figure 3. Image produced from LIDAR DEM for De Quincy 1:24,000 quadrangle, Calcasieu Parish, showing fault-line scarp along De Quincy segment within the Tepetate trend. Arrows point toward base of fault-line scarps. A = fault-line scarp cutting Lissie Alloformation. B = fault-line scarp cutting Holocene alluvium within stream valleys. ? = possible scarps of inland facing antithetic faults.

k 289 

Distribution and Origin of Fault-Line Scarps of Southwest Louisiana, USA

4 3 7

Southern fault trace and fault-line scarps region Widely scattered fault-line scarps and fault traces occur south of the Tepetate fault-line scarp trend (Fig.1). They consist of a mixture of fault traces and gulfward- and inland-facing fault-line scarps lacking any discernible regional trends. Typically, these fault-line scarps face gulfward. The height of these scarps typically ranges from 2 to 4 ft (0.6 to 1.2 m) to 5 to 7 ft (1.5 to 2.1 m). They offset relict fluvial landforms and coastal ridges found on the surface of the Beaumont and Avolleyes alloformations in many places. Although the majority of fault-line scarps found south of the Tepetate trend face gulfward, a series of inland-facing fault-line scarps occurs within Sections 14-17, 19, and 20, T.9S., R.6W.; Sections 15 and 22-24, T.9S., R.6W.; Sections 25-30, T.9S., R.5W.; and Sections 26-30, T.9S., R.4W., westernmost Jefferson Davis Parish and easternmost Calcasieu Parish (Fig. 1). The relief on these fault-line scarps is quite low being in the range of 3 to 6 ft (0.9 to 2 m). As a result, they are not readily apparent on 1:24,000 scale topographic maps although they show up quite well in images made from LIDAR data. The tectonic origin of these scarps is consistent with their morphology and demonstrated by relict channels and natural levees of the Red River, which they offset (Fig. 4).

Figure 4. Image produced from LIDAR DEM for Fenton 1:24,000 quadrangle, Jefferson Davis Parish, showing inland-facing fault-line scarp offsetting relict Red River channel. Arrows point toward base of scarps. A = scarp cutting Beaumont Allofromation. Dashed line = centerline of relict Red River channel.

k 290 

Heinrich

4 3 7

An extensive fault-line scarp system radiates from the Vinton salt dome in southwest Calcasieu Parish (Fig. 1). From the Vinton salt dome, fault line scarps extend as far as 12 mi (20 km) to the northeast, 7.3 mi (12 km) to the southeast, and 3 mi (5 km) to the west. The height of the fault-line scarps to the northeast and west is typically about 3 ft (0.9 m). In case of the longest of the northern fault-line scarps, the displacement of the fault reverses along its length such that it changes from an eastward-facing scarp to a westward-facing scarp. The fault-line scarps to the southeast of the Vinton dome typically range in height from 2 to 3 ft (0.6 to 0.9 m). The displacement of terrace surfaces, relict river channels, and coastal ridges by these scarps clearly demonstrate their tectonic origin. Fault traces and fault-line scarps are also associated with three other salt domes within southwest Louisiana (Fig. 1). Within Iberia Parish, Heinrich (2005) described a less extensive radial pattern of fault-line scarps associated with the Jefferson Island salt dome. Although the Hackberry salt dome also has fault-line scarps associated with it, they do not form the radial pattern seen in the other three salt domes. The fault-line scarps associated with both the Hackberry and Jefferson island salt domes offset relict river channels. Within the Chenier Plain, Heinrich (in press) has mapped fault traces radiating out from the Cameron Meadows salt dome. In the case of the Cameron Meadows, Hackberry, and Jefferson Island salt domes, the fault-line scarps correspond closely to known fault zones within the subsurface.

Discussion The trends and groups of fault-line scarps appear to represent differing responses to the loading of the Louisiana coastal plain by the Mississippi, Red, and Sabine rivers. The factors determining the location of the Glenmora trend faulting are unclear given the lack of a major, mapped subsurface fault zone associated with it and the lack of accessible subsurface data. One possible explanation of the position of this fault trend is provided by the presence of the southern edge of the Comachean just north of and paralleling the Glenmora trend (Adams 1985, Lopez 1995). Van Siclen (1978) suggested that faulting might be concentrated in front of the position of this former continental shelf edge, behind which the sediments are stabilized, in part, by the presence of thick carbonate sequences. In case of the Tepetate trend, the fault-line scarps are clearly associated with pre-existing growth faults. Detailed studies done by Heinrich (2000) along the China segment, by Hanor (1982) along the Tepetate fault zone in Pointe Coupee Parish, and Durham and Peeples (1956) along the Baton Rouge fault zone in Southeastern Louisiana, all indicated that the fault-line scarps are the result of the reactivation of growth faults during the Pleistocene. These results are consistent with arguments by Nunn (1985) and, later, Dokka (2004), that the reactivation of these growth faults was the result of high sedimentation rates, which have occurred within the Louisiana coastal plain and continental shelf since the start of continental glaciation. Nunn (1985) and Dokka (2004) argued that this loading has caused the reactivation of these faults as a result of a combination of tensional stress to which the underlying crust is being subjected within the Tepetate trend, gravity sliding of the Central Province of Peele et al., (1995) under its own weight, and the reactivation of the flowage of deep-seated salt. In the case of the fault traces and fault-line scarps south of the Tepetate trend, they are far too south to be explained by tensional stress on the underlying crust as suggested by Nunn (1985). The reactivation of these fault-line scarps, as argued by Dokka (2004) is readily explained as the result of gravity sliding and the flowage of deep-seated salt. The fault-line scarps associated with the Cameron Meadows, Hackberry, Jefferson Island, and Vinton salt domes quite likely reflect salt flowage at depth associated with these domes.

Conclusions The compilation of data from Heinrich and Autin 2000, Snead et al., 2002a, 2002b, McCulloh and Heinrich 2002, Heinrich et al., 2002, 2003, and Heinrich (2005, in press, in preparation) and the reevaluation of this mapping using recent LIDAR DEMs found that Late Pleistocene faulting within the coastal plain of southwest Louisiana is not limited to the Tepetate fault zone. The compilation of fault traces and fault-line scarps from these sources defines three general groupings of these features, the Glenmora trend, the Tepetate trend, and the Southern Fault trace and Fault-line Scarp region, within southwest Louisiana. Each of these groupings represents differing regional response to the loading of the Louisiana coastal plain. 291 

Distribution and Origin of Fault-Line Scarps of Southwest Louisiana, USA

4 3 7

The presence of well-defined fault traces and fault-line scarps outside of the Tepetate fault zone demonstrates that the potential for the damage to infrastructure within southwest Louisiana by fault movement is greater than previously thought. Because there is no direct evidence of earthquake activity associated with faults within southwest Louisiana, except possibly for the relatively minor 1983 Lake Charles earthquake, the hazard from seismic shaking is negligible. As a result, the main hazard posed by faults within southwest Louisiana is from movement along these faults as a result of ongoing natural subsidence, possibly accentuated at times by excessive groundwater pumping. Over time, such movement can cause cumulative damage to buildings, roads, pipelines, railroads, and other infrastructure built across them or associated antithetic faults.

Acknowledgements The United States Geological Survey under their STATEMAP program funded the geologic mapping, which made this research possible, under cooperative agreements no. 1434-94-A-1233, 1434-HQ96-AG-01490, and 03HQAG0088. In addition, support from the Louisiana Geological Survey made the compilation of the geologic map data and review of LIDAR and NED data possible. Finally, I thank Mr. Sidney Agnew, currently at the Department of Geology and Geophysics, Louisiana State University at Baton Rouge and Richard P. McCulloh of the Louisiana Geological Survey for sharing their ideas and expertise fault-line scarps and the about the use of LIDAR in mapping them.

References Adams, G.S., 1985, Depositional history and diagenesis of the Middle Glen Rose reef complex (Lower Cretaceous), East Texas and Louisiana: Masters thesis, Department of Geology and Geophysics, Louisiana State University Baton Rouge, Louisiana, 200 pp. Anonymous, 2002, Southwest Louisiana Executive Reference Map 303. Geomap Company, Houston, Texas. scale 1:280,000. Bernard, H.A., 1950, Quaternary geology of Southeast Texas: PhD. Dissertation, Department of Geology, Louisiana State University, Baton Rouge, Louisiana, 165 pp. Blum, M.D., R.A. Morton, and J.M. Durbin, 1995, "Deweyville " terraces and deposits of the Texas Gulf Coastal Plain: Gulf Coast Association of Geological Societies Transactions, v. 45, p. 53-60. Dokka, R.K., 2004, Structural characteristics of active normal faults in south Louisiana ; implications for their origin and public policy: Geological Society of America Abstracts with Programs, v. 36, no. 1, p. 26. Durham, C.O., and E.M. Peeples, 1956, Pleistocene fault zone in southeastern Louisiana: Transactions - Gulf Coast Association of Geological Societies, v. 6, pp. 65-66 Fisk, H.N., 1948, Geological investigation of the lower Mermentau River Basin and adjacent areas in coastal Louisiana: US Army Corps of Engineers, Waterways Experimental Station, Vicksburg, Mississippi, 40 pp. Hanor, J.S., 1982, Reactivation of fault movement, Tepetate fault zone, south central Louisiana: Gulf Coast Association of Geological Societies Transactions, v. 32, p. 237-245. Heinrich, P.V., 1988, Tectonic origin of Montgomery Terrace scarp of southwestern Louisiana. Gulf Coast Association of Geological Societies Transactions, v. 38, p. 582 Heinrich, P.V., 1997, Pleistocene fault-line scarps and neotectonics in southwest Louisiana: Geological Society of America Abstracts with Programs, v. 29, no. 3, p. 23. Heinrich, P.V., 2000, The De Quincy fault-line scarp, Beauregard and Calcasieu parishes, Louisiana: Basin Research Institute Bulletin, v. 9, p. 38-50. Heinrich , P.V., 2005, Surface faulting within the New Iberia, Louisiana region. Louisiana Geological Survey News Insights,vol.5, no.1, pp. 1-3. Heinrich, P.V., in press, Port Arthur Rouge 30 X 60 Minute Geologic Quadrangle: Louisiana Geological Survey, Baton Rouge. scale 1:100,000. Heinrich, P.V., in preparation, White Lake Rouge 30 X 60 Minute Geologic Quadrangle: Louisiana Geological Survey, Baton Rouge. scale 1:100,000. Heinrich, P.V., and W.J. Autin, 2000, Baton Rouge 30 X 60 Minute Geologic Quadrangle: Louisiana Geological Survey, Baton Rouge. scale 1:100,000. Heinrich, P.V., J.I. Snead, and R.P. McCulloh, 2002, The Lake Charles 30 X 60 Minute Geologic Quadrangle: Louisiana Geological Survey, Baton Rouge. scale 1:100,000. Heinrich, P.V., J.I. Snead, and R.P. McCulloh, 2003, The Crowley 30 X 60 Minute Geologic Quadrangle: Louisiana Geological Survey, Baton Rouge. scale 1:100,000.

292 

Heinrich

4 3 7

Holland, W.C., LW. Hough, and G.C. Murray, 1952, Geology of Beauregard and Allen Parishes: Geological Bulletin No. 27, Louisiana Geological Survey, Baton Rouge, 224 p. Howe, H.V., and K.C. Moresi. 1931, Geology of Iberia Parish: Geological Bulletin No. 1, Louisiana Geological Survey, Baton Rouge, 187 p. Jackson, P.H., A.N., Turcan, Jr., and H.E. Skibitzke, 1954, Geology and Ground-Water Resources of Southwest Louisiana: Geological Bulletin No. 30, Louisiana Geological Survey, Baton Rouge, 285 p. Lautier, J.,C., 1980, Geology of the Subsurface Eocene Cockfield Formation Southern Allen Parish, Louisiana: Masters thesis, Department of Geology, University of Southwestern Louisiana, Lafayette, Louisiana, 60 pp. Lautier, J.C., 1981, Geology of the Subsurface Eocene Cockfield Formation Southern Allen Parish, Louisiana: Gulf Coast Association of Geological Societies Transactions, v. 31, p. 125-133. Lemoine, R.C., 1989, Stratigraphic Framework and Sedimentary facies of the Sparta Formation (Middle Eocene), South-central Louisiana: Masters thesis, Department of Geology and Geophysics, Louisiana State University Baton Rouge, Louisiana, 60 pp. Lopez, J., 1995, Salt Tectonism of the U.S. Gulf Coast Basin: New Orleans Geological Society, New Orleans, Louisiana. scale 1:1,524,000. McCulloh, R.P., and P.V. Heinrich, 2002, Geology of the Fort Polk region, Sabine, Natchitoches, and Vernon parishes, Louisiana: Report of Investigations 02-01, Louisiana Geological Survey, Baton Rouge, 82 p. McCulloh, R.P., and P.V. Heinrich, 2004, Alexandria, Louisiana 30 x 60 minute geologic quadrangle: Unpublished map prepared for U.S. Geological Survey STATEMAP program, under cooperative agreement no. 03HQAG0088, Louisiana Geological Survey, Baton Rouge. scale 1:100,000. McCulloh, R.P., P. . Heinrich, and J.I. Snead, 2003, Geology of the Ville Platte Quadrangle Louisiana; To Accompany the Ville Platte 30 X 60 Minute Quadrangle. Louisiana Geological Survey Geological Pamphlet No.14, 11 p. Miller, B., and P.V. Heinrich, 2003, Hydrocarbon Production and Surface Expression of the China Segment of the Tepetate Fault Zone, Louisiana: Gulf Coast Association of Geological Societies Transactions, v. 53, p. 548-554. Nunn, J.A, 1985, State of Stress in the Northern Gulf Coast: Geology, v. 3, pp. 429-432. Paine, W.R., 1962, Geology of Acadia and Jefferson Davis Parishes: Geological Bulletin No. 36, Louisiana Geological Survey, Baton Rouge, 277 p. Peele, F.J., C.J. Travis, and J.R. Hossacj, 1995, genetic structural provinces and salt tectonics of the Cenozoic offshore U.S. Gulf of Mexico, in M.P.A. Jackson, D.G. Roberts, and S. Snelson, eds. Salt Tectonics: a Global Perspective: American Association of Petroleum Geologists Memoir No. 65, p. 135-167. Saucier, R.T., and J.I. Snead, 1989, Quaternary of the Lower Mississippi Valley: Louisiana Geological Survey, Baton Rouge. scale 1:1,100,000. Snead, J.I., P.V. Heinrich, and R.P. McCulloh, 1995, DeRidder [Louisiana portion] 30 X 60 minute geologic quadrangle (preliminary) map plus explanation and notes: Unpublished map prepared for U.S. Geological Survey STATEMAP program, under cooperative agreement no. 1434-94-A-1233, Louisiana Geological Survey, Baton Rouge. scale 1:100,000. Snead, J.I., P.V. Heinrich, and R.P. McCulloh, 2002a, Ville Platte 30 X 60 Minute Geologic Quadrangle: Louisiana Geological Survey, Baton Rouge. scale 1:100,000. Snead, J.I., P.V. Heinrich, and R.P. McCulloh, 2002b, The DeRidder 30 X 60 Minute Geologic Quadrangle: Louisiana Geological Survey, Baton Rouge. scale 1:100,000. Standfield, C.P., E.L. McGehee, J.L. Snead, E.B. Millet, and E.L. Nichols, 1981, Oil and Gas Map of Louisiana. Louisiana Geological Survey, Baton Rouge. scale 1:380,160. Van Siclen, D.C., 1978, Geologic Study of Faulting at Addicks Dam, Buffalo Bayou, Harris County, Texas: Unpublished report prepared for U.S. Army Corps of Engineers, Galveston District, under cooperative agreement no. DACW64-78-M-0027, Galvetson, Texas. 76 pp.

293 

Erratum to ‘‘Distribution and origin of fault-line scarps of southwest Louisiana, USA‘‘ In the legend of figure 1 on page 285 of Heinrich (2005) , the Beaumont Alloformation is incorrectly labeled as the “Hammond alloformation.” The corrected legend is below.

Reference Cited:   Heinrich,  P.  V.,  2005a,  Distribution  and  Origin  of  Fault‐Line  Scarps  of  Southwest  Louisiana,  USA.  Gulf  Coast  Association  of  Geological Societies Transactions. vol. 55, pp. 284‐293.