ass - flvc
TRANSCRIPT
Journal of Coastal Research Fort Lauderdale, Florida Fall 1995
Multiple Pliocene-Quaternary Marine Highstands,Northeast Gulf Coastal Plain-Fallacies and Facts
Ervin G. Otvos
Geology Section
Gulf Coast Research LaboratoryOcean Springs, MS 39566-7000
ABSTRACT _
.tllllllll:.ass•• •- ~ ,,0"-"-2 W
OTVOS, E.G., 1995. Multiple Pliocene-Quaternary marine highstands, northeast Gulf Coastal plainFallacies and facts. Journal of Coastal Research, 11(4),984-1002. Fort Lauderdale (Florida), ISSN 07490208.
Claims persist in the literature alleging multiple pre-Sangamonian Pleistocene, mid-Wisconsinan, middleand late Holocene marine highstands on the northeast Gulf coastal plain. These views, still encounteredeven in official publications are rooted in the assumed similarity between Atlantic and northeast Gulfcoastal history. A critical re-examination of the evidence is based on detailed sedimentary, microfossil,and geomorphic data from hundreds of drillholes and field sampling. Sediment data were matched withbasic diagnostic criteria of depositional facies.
Deposits and landforms that developed during the peak of Sangamonian transgression yielded the onlyevidence for higher-than-present Quaternary sea levels on the northeast Gulf. Pre-Sangamonian marineunits are absent in the subsurface and not exposed in coastal plain surfaces. Post-Pliocene uplift anderosion had removed littoral and nearshore units from the northeast coastal plain. Upland ridges, mistakenfor relict barriers, are elongated, high interfluves. Composed of alluvial deposits, they are bounded bysemi parallel lineaments of apparently tectonic origin and incised by stream erosion. Combined withlineaments, rare covered karst depressions on a late Pleistocene alluvial plain provide the slight relief ofsubdued linear features that had been mistaken for relict barrier islands, associated with multiple Pleistocene highstands.
Claims for wide Holocene sea level oscillations and record highstands rest on the belief, unsupportedby reliable sediment data, that the upper ridge lithosomes were essentially wave-built, intertidal anddirectly correlatable with sea level positions. However, the ridge morphology and dimensions clearlyindicate the foredune origins of discussed Florida Gulf shore strandplain ridges. Cited texture parametersand sedimentary structure types also fail to lend independent diagnostic support to the intertidal originsof the highest beach ridge intervals. Wave-cut scarps and associated supratidal narrow terraces yield noindependent proof for the postulated high eustatic Holocene sea levels.
ADDITIONAL INDEX WORDS: Beach and foredune ridges, sea level indicators, shore features, coastalscarps and lineaments, covered karst, strandplains, Silver Bluff shoreline.
INTRODUCTION
Statements on the presence of multiple Pliocene-Quaternary high marine terraces and wavecut scarps, suggested indicators of elevated sealevels on the northeast Gulf plain, keep reappearing in the coastal literature (e.g., RUPERT,
1991; DONOGHUE and TANNER, 1992). Such claimsare based on landform interpretations, includingcorrelated elevations. Flat coastwise surfaces, linear ridges and steep slopes, apparently of tectonicand/or erosional origin, have been diagnosed asmarine littoral landforms.
COOKE'S (1931) original Atlantic terrace designations (Penholoway, Talbot, Pamlico, SilverBluff), while in fact not applicable to the Gulfcoast (OTVOS, 1972) keep recurring even in officialpublications (e.g., RUPERT, 1991).
94150 received and accepted in revision 30 July 1994.
The purpose of this paper is to review claimsfor several late Neogene and Quaternary littorallithosomes. Strandplain ridges, cut terraces andscarps are also evaluated as alleged indicators ofrecord sea levels and sea level oscillations duringthe mid- and late Holocene. Higher-than-presenteustatic Gulf stands, as proposed in certain publications, would drastically alter presently accepted sea level curves.
DISCUSSION: ALLEGED LATE NEOGENEAND PRE-SANGAMONIAN PLEISTOCENE
SHORELINE INDICATORS
Late Neogene Units and Landforms
The coastal Pleistocene in Mississippi and Alabama is directly underlain by a thick undifferentiated Neogene alluvial sequence that includesthin intercalated brackish units. The Pliocene ageof this sequence locally is indicated by marine
Gulf Coast Marine Highstands 985
Figure 1. Index map ofalleged pre-Pleistocene ("A"-through"C"; + 80 m- to-+ 35 m) and Plei stocene; Tates Hell ("D ";+ 9 m and + 6 m) shorelines (DONOGHUE and TANNER, 1992;Figure O.
of Late Pleistocene and Holocene Atlantic andGulf strandplain complexes (OTVOS, 1985) onlylocally exceed 2-4 km, while ridge summits rarelyrise more than a few meters above the adjacentalluvial or lagoonal deposits of approximately thesame age. The late Pleistocene Gulfport barrierstrandplain sectors provide good examples. Theirridge elevations rarely exceed 2--4 m over the swalefloor or the adjacent alluvial surface of comparable age.
GA--- ---~--- --------
29·00'
o '"I(J~S
83"00'84·00'
o TA LL AHASSEE
\
"Marine Terraces", Northwest Florida Uplands
DONOGHUE and TANNER (1992) reiterated earlier assertions by GREMILLION and others (1964),TANNER (1966), and WINKER and HOWARD(1977),regarding the "relict ocean shoreline" origins ofupland surfaces, i.e., plains, ridges, scarps, andswales between the Escambia River and peninsular Florida. Inland, not far from the coast, ridgeelevations range between 35-50 m, and accordingto Winker and Howard, on both sides of the Apalachicola River reach c. +100 m (Figure 1). Setsof semiparallel topographic ridges , flanked bycreek valleys, led to the interpretations of interfluve ridge groups as relict barriers. WINKER andHOWARD (1977) acknowledged that these conclu sions were solely based on large-scale topo graphicmap features, not field studies.
The flat-topped interfluves are 2-8 km wide. InWinker and Howard's "Gadsden ridge sequence"in areas of Bristol and Hosford USGS Quadrangles, in sharp contrast with real barrier strandplains, upland ridge summits rise 15- 24 m aboveadjacent valley floors. In contrast , the total widths
microfossils and pollen (OTVOS, 1991, 1994; WILLARD and EDWARDS, 1994). Eastward, toward andwithin northwest Florida, the siliciclast ic Neogene sequence gradually becomes less alluvial andmore marine. Miocene and Pliocene carbonateunits appear and thicken (OTVOS, 1992). Alluvialsediments (in cluding a Pliocene alluvial se quence) form an upland surface that adjoins thenarrow Pleistocene coastal plain (Table 1).
EPOCHS, AGES GEOLOGICAL UNITS
Coastal wetlands , lagoonal , inlet , fresh and brackish water delta deposits. Mainland andHOLOCENE island barr ier strandplains, beach complexes, alluvium.
w WISCONSINAN Eolian inland dune ridges (Blue Mt. Carrabelle area) Valley fill alluviumzw GLACIAL~g:5§
SANGAMONIANPrairie Fm. (alluvial) Gulfport Fm. (barrier complex)
~ Biloxi Fm. (neritic-to-estuarine deposits)n.INTERGLACIAL Undifferentiated earty and pre-Sangamonian alluvial deposits
w UPPER Citronelle Fm. (in uplands only)zw
MIDDLE0 Undifferentiated alluvial and marine siliciclastics0:J
LOWER Perdido Key Fm. (AL-FL border area) Jackson Bluff Fm. - Intracoastal Fm.n.
w
I!:!ffi UPPER Choctawhatchee Fm. / Stage:5~ Pensacola Fm. (=? part of Intracoastal Fm.)::;
J ournal of Coastal Research, Vol. 11, No.4, 1995
986
Field studies indicated that interftuve ridges inwhat Winker and Howard called "Escambia,Wakulla, and Gadsden Shoreline Sequences" arecomposed of laterally and vertically variable, verycoarse-to-fine, silty-sand siliciclastic deposits.These units represent the late Pliocene CitronelleFormation between northwest Florida and Mississippi (OTVOS, 1972). In Georgia and adjacentFlorida areas, a correlative unit was named theMiccosukee Formation (HlJDDLESTlIN, 1988). 'I'heupland interfluve ridges reveal much greater vertical relief and wider spacing than the littoralstrandplain ridges. In terms of sediment content,texture and textural variations, morphology anddimensions, they bear no resemblance to littoralbarriers.
The strongly mottled alluvial Citronelle complex contains abundant peds, fragipans, burrows,root casts and other structures, indicative of intensive paleosol development. Shallow subtidalMiccosukee lithofacies include Uphiomorpho tracefossils in Georgia and adjacent Florida east of theApalachicola River (HUDDLESTlJN, 1988, and personal communication, 1994). However, no littoralbarrier facies identified by homogenous sand lit hosomes, well- to very well sorted, are known fromthe Citronelle-Miccosukee upland surfaces.
GOETSCHIUS (1971) produced the only noteworthy, if unsuccessful, attempt to document littoral marine origins of northwest Florida uplandssurfaces with granulometric data. He analyzednumerous sediment samples from Liberty andGadsden Counties outcrops at various elevations,without adequate stratigraphic control. Despitethe absence of associated brackish or marine fossils, GOETSCHIUS assigned these surfaces to threedesignated "marine terraces". Intervals that separate sandier "barrier" Iithosomes, because of theirgreater mud content and poorer sorting, were designated relict lagoons. GOETSCHlllS admitted thathis "barrier" sands, not as well sorted as Recentbarrier sands, are well within the sorting range ofnearby modern stream channel sands.
Following WINKER and HOWAHD in placing intertidal designations on ridges of comparable altitudes, DONOGHUE and TANNEH (1992) maintained that the "Gadsden Sequence" is "roughlycorrelatable with the Trail Ridge sequence" of thenorthern Florida peninsula. However, the TrailRidge is of entirely different origin. It consists ofwell sorted dune sands with occasional placers,representing a large coast-parallel, transgressivedune complex, decoupled and transported fr0111
Otvos
its original shore locations (FORCE and RICH,1989;FOHCE, 1991).
In contrast, the cited Florida upland ridge sequences are erosional in origin (OTVOS, 1972). Theywere incised deeply into late Neogene alluvium,apparently carved along semi-parallel tectoniclineaments that developed into stream valleys.Sedimentary and/or fossil evidence for C}ssociatedmarine, estuarine, shoreface, and intertidal/supratidal littoral (barrier) deposits is absent.
Tectonic Scarps and Lineaments (IS. Marine
Terraces and Wave-Cut Bluffs
Sedimentary and fossil evidence for "wave-cut"interpretation of Citronelle and Pleistocene scarpsis also missing. No littoral sediments, associatedwith wave deposition, have been reported fromscarp toes. Relict barrier ridge slopes are generallygentle, rarely as steep as the cited upland valleyslopes, cut into fluvial deposits. Steep slopes likethose cut into Citronelle redbeds south of Tallahassee, at Pensacola, Florida and in MississippiAlabama, apparently follow fault scarps thatbound Citronelle upland surfaces on the south.The continuity, linearity and relatively fresh appearance of Citronelle scarps suggest their tectonic origin (OTVOS, 1981).
Structural lineaments also occur in the latePleistocene Prairie coastal' surfaces as finelyetched, parallel lineaments. Lateral continuitybetween the coastal Mississippi Big Ridge Scarpand adjacent contiguous, fine lineaments on thePrairie surface (OTVOS, 1981) offer strong evidence for their tectonic origins.
Pleistocene Coastal Stratigraphy, Northeast Gulf
Coast
In correlating south Atlantic coastal plain terraces with alleged marine terraces and scarps onthe northeast Gulf and the Mississippi Embayment, COOKE (1945, 1966) correlated comparabletopographic elevations of level (H1narine terrace")surfaces and scarp faces on maps, disregardingunderlying deposits. This followed COOKE'S pioneering designation of seven Atlantic coast marine terraces, valid indicators of relict shorelinesand associated lagoonal deposits.
MACNEIL (1950) and others followed in Cooke'sfootsteps in attempting to map Gulf coastal plain"terraces" without credible sedimentological,stratigraphic, fossil, and morphological criteria.Having been trapped by Cooke's elevation criteriafor marine terraces, MAHSH (1966, Fig. 22) felt
.lournal of Coastal Hescarch. Vol. II, No.4, H)9f)
Gulf Coast Marine Highstands 987
compelled to map "Penholoway Sea" deposits atPensacola, Florida, drawing the "Sangamonian"shoreline in Citronelle alluvial redbeds at t 21 rnelevation.
Subsequent coastal plain studies (OTVOS, 1991;OTVOS and HOWAT, 1992) led to stratigraphic revisions on the basis of sedimentary and geomorphic characteristics of coastal lithofacies (e.!?,
DAVIS, 1983; REINgCK and SIN(~H, 1992, and others).
Pre-Sangamonian Pleistocene Shorelines?
The presence of multiple Gulf coastal plain littoral lithosomes, in the proximity of well-documented generations of littoral and paralic deposits ("marine terraces") on the Atlantic coastal plainof Florida and Georgia appeared so plausible afterCooke's early work (19~11) that it is still taken forgranted by some ie.g., HEALY, 1975; Rt lPEHT, 1991;DONOGHUE and TANNEH, 1992).
Designations of "marine" terraces and associated "wave-cut scarps" usually were solely basedon compatible elevations and superficial morphological similarity. with littoral features alone. Amap of northwest Florida's coastal and inland surfaces that defines "marine terraces" rigidly byelevation intervals is one example (HEALY, 1975).
It shows the entire Panhandle area between 0-- 45m elevations as underlain by one of COOKE\;, terrace surfaces (from oldest to youngest; Hazelhurst/Brandywine, Coharie, Sunderland, Wicomico, Penholoway, Talbot, Pamlico, and SilverBluff). According to our own studies, only a smallfraction of the Florida Panhandle land area isunderlain by (Sangamonian and Holocene) littoral marine sediments, the rest by late Neogeneand Pleistocene alluvium.
The tectonic setting of the Gulf coastal plainmay explain the absence of pre-Sangamoniancoastal barrier ridges and associated depositionalfacies. On the northeast Gulf, the uplift of the lateNeogene Citronelle alluvial plain to 70-100 mnorth of the narrow Pleistocene coastal plain resulted from a broad regional movement, accompanied in the entire area by deep, steep erosionalgully and stream incision. Except for limited coastparallel terraces of alluvial origin (OTVOS, 1991),
surface erosion stripped the region of all pre-Sangamonian Pleistocene littoral and nearshore rnarine units. Geodetic leveling is (HOLI)AHL andMORRISON, 1974) indicated, even today, by upliftnot far inland from the present shore.
Sangamonian Coastal Complex
Studies on the northeast Gulf coast utilizingdata from several hundred coreholes revealed thepresence of only a single transgressive-regressivePleistocene sedimentary cycle (OTVOS, 1972, 1981,1991). Deposits of the cycle overlie undifferentiated Pleistocene or Neogene alluvium and nearshore marine Neogene (OTVOS, 1992). All threemajor components (the alluvial Prairie, the neritic-to-paralic Biloxi and the Gulfport barrier deposits) are well developed on the ApalachicolaCoast, as well as along the rest of the northernGulf shore (OTVOS, 1992; Figure 3b; Table 1).
Early Sangamonian sea level on the Apalachicola Coast stood at 37 m, possibly - 48 m. Biloxidepositional facies range from inner shelf to highly brackish inshore environments. Biloxi sediments onlap Prairie alluvium, also interfingeringwith and overlain by the Prairie along the Biloxi'slandward "featheredge".
Continued regional uplift inland lifted Prairiesurfaces well above the Sangamonian peak eustatic sea level of c. t 6 m. In north Hancock County, Mississippi, the Prairie surface graduallyreaches +18 m elevation; in northwest Florida itrises above +9 m (OTVOS, 1992).
Barrier strandplains of the Gulfport progradedduring the Sangamonian eustatic highstand andthe early stage of the following regression. Scattered references in the literature to the barriersegments as "islands" notwithstanding, drillingin landward direction turned up no evidence yetfor Late Pleistocene lagoons (e.g., Figure 2).
Apalachicola Coast "Relict Immature BarrierIsland Chains"-Indicators of Multiple LatePleistocene Highstands?
Superficial map interpretations gave rise to theidea of the Tates Hell Swamp "barrier islandtrends". MACNEIL'S (1950) original idea of "Pamlico" - (Prairie) age islands has periodically reappeared in the literature (e.g., DONOGHUE, 1992,and D()NO(~HtIE and TANNEH, 1992, p. 235). Drillsample studies and a reexamination of topo graphic features refutes the validity of this approach(OTVOS, 1990a, 1992).
The alleged Pleistocene island chains 16-20 kminland were portrayed as two, 100-400 m wide, c.10 km long arcuate "sand bodies" in Tates HellSwamp, separated by a distance of 5 km (TANNER,1966). Based on their linearity and perceived topographic expression, the "sand bodies" were des-
•Journal of Coastal Research, Vol. 11, No.4, 199[)
988 Otvos
Gulf of Mexico
GUlfport Fm.
Prairie Fm.
Wisconsinan eolian r-;--,sand dunes L...!......J
Holocene
Pleistocene
,".11f-(·~:::.;f. 33 ··.34~·"'·.:-:,·: ~.•..J:..v;;:;;.::-.;;.-::i;.a~ . ':"-....;. ..1 •••:.:3~~~-
1- .'~.•~-=-- Apalachicola
31 St. v; ~A./29 30 "ce"t I". Bay , 39
~~ 01 5 10km ~ <In.0 B'~v . I , G00 ' 'tJ
(;,;)tti
~0
dli
Inland "rldqes"
Figure 2. Apalachicola Coast Pleistocene units, NW Florida. Drillhole locations and surface geology (OTVOS, 1992).
ignated as remnants of two (+6 m and +9 m)Pleistocene shorelines. TANNER claimed that the"relict island" bodies rise 1-4 m above the adjacent plain. Correctly, BRENNEMAN (1957) mentions only 60-120 em surface relief, associated withthese narrow, discontinuous slightly elevated stripsof ground. Brenneman's sediment samples, takenfrom just below the land surface, revealed poorsorting. Abandoned logging railroad embankments, located on these strips, slightly enhancedthe ridge elevations (Figure 4, right).
A detailed study of 36 Apalachicola Coast drillcores and surface geology (OTVOS, 1992) indicatedthat Tates Hell Swamp is directly underlain byfossil-free, poorly-to-very poorly sorted oxidizedsilty sands and sands of the Prairie Formation.Neogene siliciclastics and carbonates occur beneath (OTVOS, 1990a, 1992). The Prairie, at 1214 m depth is underlain by karstified Late Neogene carbonates that rise near the land surfacetoward the southeast.
If the Tates Swamp "sand ridges" were relictbarriers, they would be associated with Sangamonian marine littoral and paralic units in the
surface and subsurface. However, while littoraldeposits are well developed along the mainlandshore, they are absent from the Tates Hell "ridge"areas (Figures 2 and 3A,B). Corehole #6, drilledthrough the northern "ridge", for instance, didnot encounter any marine or brackish deposits.The muddy Prairie sands in the boring were identical in composition and appearance to Prairiesands elsewhere and did not represent discretelinear sand bodies.
BRENNEMAN and 'TANNER (1958) invoked amassive influx of muddy delta deposits to explainpoor sorting of these "not extensively reworked,immature barrier island deposits". Poor sortingwould be most atypical of beach sands on evenrelatively low energy, nonglacial shores, for instance Louisiana's. However, from kurtosis valuesof the muddy sands alone, and DONOGHUE andT ANNEH (1992, p. 2:)5) paradoxically assumed, notlow-energy but "moderate to high wave energy",condiLions for the inferred island shores.
Slightly raised Tates Hell "ridges" actually werepartly related to dissolution processes in shallowunderlying carbonates. Covered karst develop-
Journal of Coastal Research, Vol. 11, No.4, 1995
Gulf Coast Marine Highstands 989
A A'
wsw ENE
MARINE FACIES ffiII]]PRAIRIE FM (1) ~:-~
m.5
-10
-30
-20
-50
-40
10 km
27
APALACHICOLA
26
LIMESTONE·
UNCONSOLIOATED
CALCAREOUS
SIUCIClASTlC
NEOGENE
3433
oC3
3231
~r_,)(::::;)a
HOLOCENE
PLEISTOCENEGULFPORT FM
BILOXI FMBRACKISH FACIES _
29 30
-150
-100
-ISO '
-so
.20'
8 N 5 E
-20
-40
-60
5 6 TATES HELL SWAMP 12 18 44 45 46 39.10
mST_
GEORGEISLAND
o
-2
oIo
ml,10 km
Line 8
Figure 3_ A,B. Apalachicola Coast cross sections. A- -thick Pleistocene sequence, overlying the Neogene sequence, Cape San BlasApalachicola River cross section: B- -T ates Hell Swamp cross section, Note thick Prairie alluvium and absence of non-terrigenousPleistocene deposits (Orvos, 1990, 1992) in Drillhole n6, alleged site of one " immature barrier island".
Journal of Coastal Research, Vol. II, No, 4, 1995
990 Ot vos
Figure 4. Left and right. Pr oir ie alluvial coas tal su rface with covered ka rst morphology, USGS Tates Hell Swamp Orthoph otoQuadrangle, NW Fto rida , 198 1. O- irregu la r ly sha ped , sha llow depress ions; S - circu lar a nd ova l sinkhole depressions. " Ridge ' setsI and 2- frac ture-tfan ked, d iscon ti nuous, s ligh tly eleva ted nar row bel ts (alleged " bar rie r island " gen erations of MACNEIL, 1950;BRENNEMAN and TANNI.:n, 1958; and OONO<: HIIIi and T ANNP.R, 1992). Arr ows without letters po int to s traight, fra cture-defineddepression rim s. Contours in mete rs.
.lour nal of Coasta l Resear ch , Vol. II , No.4 . 1995
Gulf Coas t Marine Highstands
Figure 4. Continued.
991
ment manifests itself in interconnected broad, irregular, amoeba-shaped surface depressions (Fig ure 4, left and right), previ ously unreported . Thelargest, less than 1-2 m deep, are 4.5- 8 km wide.Numerous oval-cir cular sinkhole outlines, 150-300m in diameter were imprinted in rim s and floorsof the large shallow basin s (Figure 4,Ie ft and right).
Straight depression rims revea l a rectangularfracture network. Parallel frac tures bound narrow, slightly elevated, slightly better drained andtherefore ligh ter-toned zones. As slight " in terfluve highs", they sepa ra te adjoining depressions.Discon t inu ous, flat- topp ed stri ps on aerial photog ra phs and topog raph ic maps created the false
992
appearance of high, elongated ridges (Figure 4,left and right).
These unique features mark the only northernGulf Pleistocene coastal area with covered karsttopography. The young drainage network is stillpoorly integrated. On the northern Gulf, coveredkarst with deep depressions was previously reported only from nearby Citronelle uplands (OTVOS, 1976).
Adopting COOKE'S approach to terrace designation on the Apalachicola Coast, HEALY (1975)and RUPERT (1991) combined Sangamonian marine barrier sectors with those of extensive Prairiealluvium, under the heading "Pamlico marine terrace". They also merged parts of the PleistocenePrairie ("Pamlico") plain with Late Holocene andRecent barrier and subaerial delta surfaces. Thisunusual blend of disparate surfaces was labeledthe "0-10-ft Silver Bluff Terrace"; its age, designated as Pleistocene or Holocene.
Mid-Wisconsinan Highstand?
Although uniformly dated worldwide at 135105 ka, highest deposits of the last marine (Sangamonian) highstand, on occasion, have been assigned to the Mid-Wisconsinan (BRENNEMAN andTANNER, 1958) and sediments of the second youngest highstand, to the Sangamonian Interglacial(e.g., MARSH, 1966, for other references, In: OTVOSand HOWAT, 1992). In the upper Midwest wherethe idea originated, the concept of a mid-Wisconsinan interglacial has long been discarded. Morerecently and without more validity, the briefFarmdalian interstade (c. 28-24 ka BP) in themidst of the Wisconsinan glaciation has been mistakenly identified by some (In: OTVOS and HOWAT,1992) as a time of a sea level that closely approached the present one.
Alleged Mid-Holocene Record Sea Levels
Cooke and MacNeil were among the first tosuggest extreme high mid-Holocene sea levels onthe southeast Atlantic coast. Later, PARKER andCOOKE (1944) introduced the term "Silver Bluff"in southeast Florida for a late Pleistocene wavecut scarp, thought to be indicative of raised (+1.83.0 m) sea levels. Between Wakulla County andPensacola, Florida, MACNEIL (1950) tentativelycorrelated a "Silver Bluff shoreline" with a postulated + 1.8-2.4 m sea level, associating it withthe mid-Holocene climatic optimum, 6-4 ka BP.
Fairbridge repeatedly claimed mid-and lateHolocene record sea levels on the Gulf and At-
Otvos
Iantic coasts. His mid-Holocene + 2 m sea levelon a Miami area reef platform (FAIRBRIDGE, 1992)is based on the carbonate fraction of apparentlyreworked sand, associated with much youngermangrove roots. This unit is actually located within the present intertidal zone (see: HOFFMEISTERand MULTER, 1965, p. 874), not above the presentintertidal range.
WHITE (1970) believed that at its Miami typelocation the Silver Bluff formed in part and isbeing maintained by occasionally recurring stormwave erosion.
The existence of a high "Silver Bluff" shorelineand associated lithosomes could not be verifiedon the Gulf seaward of the Sangamonian littoralcomplex. Sea level data (e.g., NELSON and BEAY,1971; OTVOS, 1991) also indicate that between 6and 4 ka BP sea level rose from c. -7 m, to - 3 m.
Suggested Evidence for Middle and LateHolocene Highstands
Shore Scarps and Small Incised Terraces. STAPOR(1973,1975) described scarps and associated smallterraces at +1.5-3 m above sea level, cut in Pleistocene barrier ridges at several Alabama andnorthwest Florida locations. His belief in midHolocene highstands in part was based on thefresh appearance of a high mainland scarp in NWFlorida that faces an archeological site, seaward.The site included Norwood fiber-tempered ceramics of 3-4 ka BP age (STAPOR, 1973; BRALEY,1982). Because it was thought incapable of outlasting a postulated record transgression abovepresent sea level, the Indian midden was considered to postdate the scarp.
However, survival of the archeological site initself does not represent credible evidence. Noassociated and dated littoral sediments were foundto prove the alleged highstand. At the same time,hundreds of Indian sites, regularly exposed tostorm erosion, still endure in intertidal-low supratidal shore zones. Several sites, presently exposed on the flat inner shelf floor had not beeneliminated even by the overriding transgression(e.g., DUNBAR, et al., 1992).
A narrow cut-terrace of Magnolia Bluff, on theeast bank of the Apalachicola estuary, carved fromGulfport barrier sands was similarly cited in support of the late Holocene highstand. DONOGHUE(1993) dates its development as preceding that ofApalachicola Bay by barrier islands that emergedc. 4 ka BP. In this view, wave intensities dimin-
.lournal of Coastal Research, Vol. 11. No.4, 199)")
Gulf Coast Marine Highstands 993
Figure 5. Erosional terrace and scarp, cut into Late Plei st ocene barrier at c. 0.9-2 m above sea level. Narrow Mississippi Soundbeach. left. East Belle Fontaine Beach, Missi ssippi.
ished afterward , precluding scarping and terracecutting.
Mainland shore bluff scarps, including that of12 m high Royal Bluff cut into a large dune (OTVOS, 1992), however, testify to highly erosive stormevents even on relatively protected bay shores.Storm surges here reached +2.4 m during the1972 and 1985 hurricanes.
A similar, narrow incised terrace at +0.9 to +2m elevation illustrates the same point on Mississippi's mainland shore. The small Belle FontaineBeach terrace in Jackson County was also carvedby storms from Gulfport barrier sands and humate-cemented sandstones. Approximately 100 mlong and 0.5-6.5 m wide, it is bracketed by the 12-m backshore bluff on the Mississippi Soundshore and a lower scarp, in landward direction(Fig. 5).
Another "marine terrace", regarded as highstand indicator by STAPOR (1973, 1975) at Pensacola Naval Air Station in northwest Florida,
occurs off the Gulfport barrier toe . In contrast, itis an aggradational feature. Actually, it is thesurface of a late Holocene dune strandplain thatrises to + 1.5- + 3.0 m elevations. Naturally, thissurface is unrelated to record Holocene sea levels,except indirectly to the cur rent one.
In Search of "Highstand" Sediments
Wave-Constructed Ridges; Eolian and SwashLamination. TANNER and STAPOR (1975, 1991) andSTAPOR et al . (1989, 1991) asserted that strandplains of Florida beach ridges formed essentiallyby wave runup and swash-backwash deposition,not eolian processes. Differences in ridge set elevations were thus attributed to oscillating LateHolocene sea levels. Narrow, often steep activeforedunes on west Florida's Lee County barrierislands, on St. Joseph barrier spit and other Apalachicola Coast strandplain shores have been rejected as alternate models of ridge development.Statistical parameters of sedimentary textures and
.lournal of Coastal Res ea rch, Vol. I I , No.4 , 199:;
994 Otvos
Figure 6. Horizontal and gently cross- lam ina ted eol ian sand layers that mimic foreshore lamination. Active dune field, cut byretreating 2-3 m Gulf backbeach scarp. East of Dauphin Island Fishing Pier, Alabama. (Scale units: in and em)
certain structures were invoked as tools in distinguishing between eolian and subaqueous littoralfacies .
Distinguishing Subaqueous Facies by TextureParameters. TANNER (1991) used mean , sorting,skewness and kurtosis st.atistics, and statisticalparameter cross-plots to interpret fifty-nine St.Vincent strandplain ridge sam ples as intert.idal inorigin . Low skewness values of sample sets wereclaimed as hallmarks of "mature" beach, not ofeolian sands. Crossplots of kurtosis and sortingvalues were correlated with topographic low andhigh ridge sets. Low ridges were viewed as markersof marine lowstands, tall ones as highstand indicators.
One major objection t.o this approach is the lackof objective, empirical field comparison and ver ification, based on a sufficiently large number ofsamples, obtained from a variety of modern depositional environments. While TANNER assertedthat in most beach ridges the eolian sand component amounts to 5-20'10, the method and itstheoretical foundations on which t.he intertidal
and eolian sand ratios were established also remain unclear and therefore unconvincing.
In addition, the plotting of averaged group values ("suite statistics") not of individual samples,prevents recognition of overlaps between eolianand intertidal sample fields on the diagrams. Thismay lead to preconceived and arbitrary facies assignment of certain samples to given facies categories before their statistical parameters are submitted t.o further calculations.
Facies Identification by Sedimentary Structures.Parallel and low-angle cross laminae, describedfrom the Apalachicola Coastas examples of "swashzone bedding". occur in beach ridges as high as 3m above mean sea level (STAPOR, 1975). Nearhorizontal , parallel- and low-angle cross stratification was postulated to be an intertidal feature.This infers their formation during a higher-thanpresent Holocene sea level stage (STAPOR et al.,1991, Figure 5).
However, these sedimentary structures are notrestricted to intertidal sands. Laminae in eolianridges may mimic the semiparallel bedding and
Journal of Coastal Research , Vol. l l , No.4 , 1995
Gulf Coast Marine Highstands 995
low-angle cross lamination in the beach foreshore(DAVIS, 1983, Figure 12-11). This happens in dunecuts, perpendicular or at low angles to the sandtransport direction. As one example, an erodingbackbeach scarp that cuts through a very extensive and active dune complex at Dauphin Island'sFishing Pier, Alabama, exposes the very same"beach"-lamination types 2-3 m above Gulf level(Figure 6).
In addition, during temporarily elevated sealevels not accompanied by significant erosive activity, swash action by large, constructive swellwaves may deposit low-angle cross.-stratified setsand horizontal, planar swash laminae on landward- and seaward beach ridge slopes (see also:Figure 14, HEQUETTE and RUIZ, 1991).
Geomorphic Argument. Origins of the ShellComponent
Narrow, 2-4 m sand ridges of well sorted, white,medium sand, typical of Holocene mainland andisland Gulf strandplains, clearly are not wavebuilt intertidal berm (swash) ridges (Figures 7A,B).The uneroded, steep slopes of relatively very recent strandplain ridges (e.g., Figures 7A,B) testifyto their beach foredune origins. Eolian aggradation is the only mechanism that builds such ridgesappreciably above high tide level under normalwave conditions. When the wind-transported origin of the upper ridge lithosomes is recognizable,only the base of the eolian interval, related to thesea level during the ridge-forming time interval,acts as a constraint in marking sea level positions.It defines the maximum elevation of the underlying intertidal ridge interval.
The presence of large shell fragments in coastalridges especially on shell-rich, quartz sand-starvedshores, may not be explained by eolian transportmechanism, only by locally nondestructive overwash processes. Large, constructive swell wavesovertop dune ridges during raised sea level episodes. Shelly sand layers lodged on dune surfaces,as in the past on southwest Louisiana's cheniers,occasionally contributes to ridge aggradation.
NORTHEAST GtJLF COASTAL SITESARGUMENTS FOR HOLOCENE
HIGHSTANDS
Central West Florida (Lee County) BarrierIslands
STAPOR et al. (1987,1991) assembled numerousradiocarbon dates from six barriers. The islands
are very low, generally of 1.2-2.7 m ridge elevation. Vertical exaggeration of the cross sectionscreates the impression of steep ridge slopes (Figure 8, right). Ridge top elevation values and radiometric dates were offered as proof for higherthan-present Holocene Gulf levels.
None of the fossil beach ridge sets on the islandswere considered eolian by these authors, and theirsummit elevations were regarded directly correlatable with late Holocene highstand episodes.Stapor and others (1991; their Figures 6a,b, 14)cited the "Wulfert" and "La Costa" (Lacosta; CayoCosta) ridge generations, with elevations thatmatch those of current foredunes (Figure 8, leftand right), as evidence for a + 1.2 m marine highstand between 2-1.5 ka BP.
Equally puzzling, other ("wave-built"?) ridges,formed as recently as the last century when eustatic sea level was slightly lower than presently,apparently were also related to + 1-3 m marinehighstands (Figure 8, left and right).
In agreement with Stapor and others, that thehighest "swash" island ridges formed during record marine highstands, DONOGHUE and TANNER(1992, p. 239) seized on Stapor's 3.0-2.7 ka dates,claimed by him as derived from the highest ridgesand thus reflecting +2.4-3.0 m Holocene highstands. It is noted, however, that the cited dateswere obtained not from the highest but lower (0.61.5 m) ridge sets (see: STAPOR et al. 1991, Figures2,9, 14).
As with other Gulf coast examples, the conclusion that at least the upper ridge lithosomes (Figs.7a,b) are eolian in origin and the ridge summitsare only indirectly related to late Holocene sealevels, is inescapable.
St. Vincent Island Strandplain; Ridge Elevations,Ages, and Island Genesis
(a) Ridge Elevations and Sand Granulometryas Perceived Indicators of Sea Level Fluctuations
Sizable St. Vincent Island (Figure 2), locatedoff the Apalachicola Coast west of the Apalachicola Delta in northwest Florida, is the site of oneof the most spectacular Gulf coast strandplains.It is composed of a number of ridge generations.
Utilizing their previously cited approach thatbased on granulometric statistics assigns intertidal origin to beach ridges and directly correlatesridge summit elevations with sea level stands,TANNER and coauthors postulated seven-to-ninesignificant sea level changes during island devel-
Journal of Coastal Research, Vol. 11, No.4, 1995
996 Otvos
Figure 7. A,B. Examples of steep-sloped late Holocene strandplain ridges; relict foredunes-not intertidal berm (swash) ridges.Apalachicola Coast, NW Florida. A-northeast of Cape San BIas Plantation, E of Drillh ole 30 locat ion (Figure 1 in Or vos, 1992);B-just south of entrance to Peninsula State Park, central St. Joseph Spit (S of Drillhole 21, Figure 2). Ridge elevations: c. 3.5-4 .0m above road level (Orvos, 1992).
J ournal of Coastal Research, Vol. 11, No.4, 1995
Gulf Coast Marine Highstands 997
opment (e.g., STAPOR, 1975; TANNER et al., 1989;TANNER (1991), DONOGHUE and TANNER, 1992).
(b) Ridge Elevation Differences and LocalizedSubsidence
In contrast with the 4.5-5.7 m (15-19 ft) maximum ridge elevations in the younger southernisland area, the generally subsea-to- + 1.2 m elevation range of the northern ridge tops seem influenced by differentiated and in part localizedcompactional ridge subsidence into underlyingmuddy sediments. Highly conspicuous lateralvariations in elevation within given ridge sets mayin part have the same origins.
Due to the great morphologic and size similarities between the least eroded, youngest strandplain ridges and present active beach foredunes,there is little doubt about the essentially eoliannature of the beach ridges. They may reflect pastsea level stands only indirectly.
(c) Island History; Archeology and BeachRidge Chronology
Radiometric Dates. Two shell dates, both fromthe northeastern island corner (BRALEY, 1982, andSTAPOR, 1975), were the only ones published fromthe island.
The first originated from one of the culturallayers of the sizable Paradise Point shell mound;Site 8Fr71 (1320 yr BP; corrected to 1710 yr BP;BRALEY, 1982, p. 38). On archeological grounds,BRALEY expressed some misgiving about the date'sdependability. STAPOR (1975) and following him,BRALEY (1982) believed that the date reflects sealevel rise that partially drowned the mound. Asubsequent sea level decline was also assumed.
Compactable and thick underlying muddy unitsmay have contributed to subsidence of the mound.The slightly elevated position of muddy depositsof unknown origin, over one cultural layer, is hardlyan independent proof for elevated sea level stage.
The second dated sample available from theIsland (c. 2110 yr BP; STAPOR, 1975), from theMallard Slough shore area, was from quartz sandtaken near the eroding east terminus of a beachridge. The sand may have come from a shallowsubtidal interval, located beneath a subsequentlyremoved ridge sector. A 5 m thick, compactable,"soupy" mud unit underlies the sand (Stapor,written comm.; OTVOS, 1992, p. 230).
Despite the lack of associated absolute dates,TANNER (1993a) suggested that a large part of theisland, a 1 km wide Ridge Set G, bracketed be-
tween two, somewhat higher, wide ridge sets (map:TANNER, 1993a, Figure La), formed during a subrecent "Little Ice Age lowstand".
Starting c. 1450 A.D., this cooler interval lasteduntil the first half of the 19th century (VAN ANDEL,1981). In other views, it was more restricted (15701730 AD; e.g., SCHOVE, 1987, p. 359). Certain detailed historical records (e.g., TERS, 1987, p. 209)strongly indicate that these climate fluctuationsdid not appreciably, or even recognizably impactglobal sea levels.
TANNER (1993a) proposed ridge-set correlationbetween St. Vincent and a north Danish strandplain. In view of the substantial isostatic readjustment and other factors that affected Scandinavian shores, the correlation is highlyproblematical.
New Orleans Barrier Trend-Mid-HoloceneHigh Sea Level Evidence?
A buried mid-to-late Holocene barrier complex,composed mostly of shallow subtidal sand lithosomes is covered by late Holocene delta depositsunder eastern New Orleans, Louisiana. Ridgesummits at a few locations extend above sea level(+0.5 m in New Orleans and at Lake St. Catherine, to the east).
STAPOR et al. (1987, p.152; 1991, p. 833) mistakenly cited OTVOS (1978) as suggesting that exposed ridge summits and perhaps high subsurfacesand lithosomes, apparently suspected by Staporas intertidal in origin, reflect amid-Holocene, c.5 ka BP, marine highstand. Shallow submarinedeposits, including bars and shoals, occur in theshallow subsurface. Identifiable shallow subtidaldeposits do not occur above present sea level.
Exposed sand bodies, strongly altered by soilprocesses have been considered relics of supratidal, eolian bodies that probably capped islands thatwere part of the barrier complex (OTVOS, 1978).Portions of the dune lithosomes may have subsequently subsided below Gulf level. A complicating factor is the uncertain rate of still continuing subsidence. Judging from historic subsidence rates based on tidal gage records; they varied considerably within the New Orleans area(OTVOS, 199Gb).
Louisiana Cheniers-Postulated Proof of LateHolocene Record Highstand?
Employing granulometric parameter crossplotsand ridge elevation-sea level correlation in Louisiana's chenier plain, DONOGHUE and TANNER (1992,
998 Otvos
E --~~-+---- E I
~~n
A
~
~8
Beach ridge patterns (diagrammatic)= _=_==_--- Constructed 1860-1952- ------~~ Constructed Prior to 1860
Calcarenite exposures •
Mangroves
Sampling Sites 1Indian site @
Pleistocene (?) dune
~~
~
~o
LACOSTA IS. C'
I U5 0 I km
~-- ..
c==J Sanibel I (3000-2000 Yr. BP)
1:::::::::::::1 Wulfert (2000-1500 Yr. BP)
[>::::::~'::::-J Buck Key (1500-1000 Yr. BP)
c=J La Costa (1000-500 Yr. BP)
Journal of Coastal Research, Vol. 11, No.4, 1995
Gulf Coast Marine Highstands 999
A/RIDGE.S BUILT 1860-1950 A'
9'~III
MS~~~520~!.LJmLA COSTA ISLAN D
O.5km1- --',
B{RIDGES BUILT 1860-19509' \-. [[]
6'~~- " ._ . 10
M:~~"'> ;LA COSTA ISLAND
B'
r_ . =.~
VERTICAL EXAGGERATION 100: 1
BUCK KEY (1500-1000 YR. BP)
LA COSTA (1000-500 YR. BP)
MANGROVES
C-14 SAMPLING SITE
I ;\: 1
c=Jc=;am
I ii SANIBEl I (3000-2000 YA. BP)
2 m 1:::;:::;:::;:::;1 WULFERT (2000-1500 YR. BP)
3000 FEETI
LA COSTA ISLAND
1500o
::~3'
M SL L-,..;-:";':"-;'_,-,-..;......
Figure 8. Left and right. Late Holocene and historic beach ridge sets, Lacosta (La Costa, Cayo Costa) Island, central West Floridacoast (after STAPOR et al., 1991). Left-map of ridge generations; right-profiles across Island. Gulf shore on left . Compare "highsea level" Wulfert set summit level, section C with number 2; historic (subrecent) ridge sets.
p. 239) and TANNER (1993b,c) concluded that sealevel oscillations of 1-2 m, respectively, 1-6 m(!)amplitudes did typically take place in the pastthree thousand years. Chenier ridges formed during Late Holocene highstands; inter-ridge lows,during lowstands.
Detailed lithofacies and biofacies studies(BYRNE, et al., 1959, Plate 2; and other publications) revealed simple vertical and horizontal facies relationships of the Louisiana chenier complex. Microfossil and lithofacies data establishedthe depths and shore positions of subtidal-nearshore and inner shelf-bay facies. Intertidal facieswere also identified in ridges and interveningmudflats and marsh deposits.
The consistently shallow depths of subtidalintertidal depositional facies provides ample evidence for a quite stable late Holocene sea level
during chenier and mudflat progradation. Thepostulated major swings between low- and highstands would translate into onlap/offlap relationships. These would be drastically different andmore complex than what is well established fromdrill data (BYRNE et al., 1959). Highstands, inaddition, would have also laid down Holocene sed iments far north of the present seaward limit ofPleistocene surface deposits.
Record high Holocene sea levels would not berequired to explain the large proportion of shelldebris in chenier ridges. Shell debris occurs ashigh as 3.3 m (11 ft) above mean sea level in OakGrove Ridge chenier (750-850 AD; BYRNE et al.,1959, Fig. 8), although most cheniers reach only1.2-2.0 m above mean sea level. Those had beenmore often impacted by overwash.
As to a much lesser extent in Lee County, Flor-
Journal of Coastal Research, Vol. 11, No.4, 1995
1000
ida, non-erosive wave action, probably large swells,during temporarily raised sea levels lodged abundant shell debris on dune slopes on this quartzsand-starved coast. Landward-dipping washoverlaminae, also illustrated by KACZOROWSKI (1978),added large volumes of shelly sand to the chenierridges.
Suggested Evidence from an AlabamaArcheological Site: Inferred High Holocene SeaLevels
HOLMES and TRICKEY (1974) described threemud layers, sandwiched between radiocarbondated cultural horizons in an Indian mound onTensaw River, c. 42 km inland from Mobile Bay.An episode of mud deposition at +0.6 m, at onetime between 4100-3090 yr BP, and another at+1 m, in the 2040-3090 yr interval coincided withtimes of assumed highstands, marked in a 1961sea level curve.
Two high sea level episodes, associated withmud-emplacing flood events were suggested.However, tropical storm tides in Mobile Bay orrecurring river floods from inland may well account for a minor stream level rise, a logical alternative to longer-term sea level fluctuation. Thusfar, this highly isolated archeological data fail tomake a convincing case for record Gulf highstandlevels.
CONCLUSIONS
Despite a sizable body of literature publishedsince C. W. COOKE'S pioneering Atlantic coastcontributions six decades ago, valid evidence exists only for a single Pleistocene highstand. A fewpre-Sangamonian Pleistocene coastwise terraceremnants, composed of alluvial deposits have beenidentified. Most alluvial and all marine units havelong been stripped by erosion during the still continuing regional uplift that raised the late Pliocene alluvial plain of the coastal uplands to + 7590 m (OTVOS, 1991, 1993). Attempted correlationsof pre-Sangamonian southeast Atlantic littoralfeatures with northeast Gulf coastal surfaces andother allegedly littoral landforms were based onsuperficial similarities.
The Late Pleistocene Gulfport barrier represents the only Pleistocene marine unit exposed inthe coastal plain surface. It is part of the Sangamonian sedimentary cycle that includes alluvialand neritic-to-inshore members as well.
Disputed indicators of marine highstands fallinto two categories. The first involves topographic
Otvos
features that mimic coastal landforms. These werecarved from alluvial deposits, often along parallelfractures of tectonic origin. Interftuve ridges and(tectonic) scarps that superficially resemble barrier ridges and wave-cut scarps formed, as a result.In a unique coastal plain sector with karstic landforms, surface depressions combined with apparently tectonic lineaments mistakenly led to claimsof late Pleistocene marine highstands and associated shore ridges at + 6 and +9 m elevations.
The second category involves littoral lithosomes and landforms. These are equally unsuitedas Holocene highstand indicators. Despite theirbackshore dune ridge morphology, several authors regarded them essentially as intertidal. Sediment granulometry and structures provide noconvincing evidence for assuming their intertidalorigin and for relating ridge elevations to assumedsea-level oscillations.
In the absence of sedimentary and fossil evidence, elevated scarp toes, notches, and narrowterraces, cut into Pleistocene barrier sand ridgeson lagoonal shores, fall in the same category. Theywere excavated and maintained by recurring stormprocesses at a time when sea level did not standsignificantly lower or higher than today.
Higher-than-present Holocene littoral lithosomes are abundant in areas affected by postglacial isostatic rebound. Similarly, even brief episodes of postulated raised sea levels would haveleft ample sedimentary proof of onlap behind. ThinHolocene littoral and paralic lithosomes of suchrecord highstands would overlie oxidized Pleistocene surface deposits a few feet above sea level.Their absence on the Pleistocene coastal plainrepresents a decisive argument against assumedrecord highstands. Well documented mid -to-lateHolocene Gulf sea level positions (e.g., NELSONand BRAY, 1971; OTVOS, 1991) also refute suchspeculations.
ACKNOWLEDGEMENT
I appreciate correspondence, pertinent references, and reprints received from Drs. Stapor,Tanner, and Donoghue in the course of manuscript preparation. Incisive and highly constructive editorial comments by Richard A. Davis, Jr.and an unnamed reviewer were received with sincere gratitude.
LITERATURE CITED
BRALEY, C.O., 1982. Archeological testing and evaluation of the Paradise Point Site (8Fr71), St. Vincent
Journal of Coastal Research, Vol. 11, No.4, 1995
Gulf Coast Marine Highstands 1001
National Wildlife Refuge, Franklin County, Florida.Report, Southeastern Wildlife Services, Inc. Athens,Ga, 102 p.
BRENNEMAN, L., 1957. Preliminary Sedimentary Studyof Certain Sand Bodies in the Apalachicola Delta.M.S. Thesis, Florida State University, 151 p.
BRENNEMAN, L. and TANNER, W.F., ]958. Possible abandoned barrier islands in panhandle Florida. Journalof Sedimentary Petrology, 28, ~42 -~~44.
BYRNE, J.V.; LEROY, D.O., and RILEY, CH.M., 1959. Thechenier plain and its stratigraphy, southwestern Louisiana. Transactions of the Gulf Coast AssociationGeological Societies, 9, p. 2~37-260.
COOKE, C.W., 1931. Seven coastal terraces in the Southeastern States. WashinRton Academy of SciencesJournal, 21, 503-513.
COOKE, C.W., 1945. Geology of Florida. Florida Geological Survey Bulletin, 29, :t~9.
COOKE, C.W., 1966. Emerged Quaternary shore lines inthe Mississippi Embayment. Smithsonian Miscellaneous Collections, 149, 41.
DAVIS, R.A., JR., 1983. Depositional Systems. New York:Prentice-Hall, 669p.
DONOGHUE, J.F., 1992. Late Quaternary coastal and inner shelf stratigraphy, Apalachicola Delta region,Florida. Sedimentary Geology, 80, 29~~-:j04.
DONOGHUE, J.F., 199:3. Northeastern Gulf of MexicoCoast. GSA Southeast Section Field Trip GuidebookNotes, Tallahassee, Florida, 5-1:t
DONOGHUE, J.F. and TANNER, WM.F., 1992. Quaternaryterraces and shorelines of the Panhandle Florida region. Quaternary Coasts of the United States: Marineand Lacustrine Systems, SEPM Special Publication,48, 233-241.
DUNBAR, J.S., and others, 1992. Inundated prehistoricsites in Apalachee Bay, Florida, and the search forthe Clovis shoreline, p. 1]7-14G. In: ~J()HNSON, L.L.(ed), Paleoshorelines and Prehistory, Boca Raton:CRC Press, 243 p.
FAIRBRIDGE, R.W., 1992. Holocene marine coastal evolution of the United States, p. 9-20. In: FLETCHER,Ch.H., III and WEHMILLER, JOHN E., (eds), Quaternary Coasts of the United States: Marine and Lacustrine Systems, SEPM Special Publication No. 48,450p.
FORCE, E.R., 1991. Geology of Titanium-mineral Deposits. Geological Society of America Special Paper,No. 259, 112 p.
FORCE, E.R. and RICH, F.~J., 1989. Geologic evolution ofTrail Ridge eolian heavy mineral sand and underlyingpeat, northern Florida. [T.S. Geological Survey Professional Paper No. 1499, IG p.
GOETSCHIUS, D.W., 1971. Preliminary Sedimentologicaland Geomorphological Study of Certain High TerraceSands Between the Ochlockonee and ApalachicolaRivers, Liberty and Gadsden Counties, Florida. M.S.Thesis, Florida State University, 99 p.
HEALY, H.G., 1975. Terraces and Shorelines of Florida.Florida Bureau of Geology Map Series No. 71.
HEQUETTE, A. and RlTIZ, M.-H., 1991. Spit and barrierisland migration in the southeastern Canadian Beaufort Sea. Journal of Coastal Research, 7, 677 -698.
HOFFMESSITER, J.E. and MllLTEH, H.G., ]965. Fossilmangrove reef of Key Biscayne, Florida. GeologicalSociety America Bulletin, 76, 845-652.
HOLDAHL S.R. and MORRISON, N.L., 1974. Regional investigations of vertical crustal movements in the U.S. using precise releveling and mareograph data. Tectonophysics, v. 23, p. 373-390.
HOLMES, N.H., JR. and TRICKEY, E.B., 1974. Late Holocene sea-level oscillations in Mobile Bay. AmericanAntiquity, 39, 122-124.
KACZOROWSKI, R.T., 1978. The Chenier Plain and Modern Coastal Environments, Southwestern Louisiana.In: ETTER, E.M., (ed.) Guidebook, Houston Geological Society, 1-55.
MACNEIL, F.S., 1950. Pleistocene shore lines in Floridaand Georgia. LIS Geological Survey Professional Paper 221-F, 95-106.
MARSH, O.T., 1966. Geology of Escambia and Santa RosaCounties, Western Florida Panhandle. Florida Geological Survey Bulletin No. 46, 140 p.
NELSON, H.F. and BRAY, E.E., 1971. Stratigraphy andhistory of the Holocene sediments in the Sabine-HighIsland area, Gulf of Mexico. Deltaic Sedimentation.SEPM Special Publication 15,48-77.
OTVOS, E.G., 1972. Pre-Sangamon beach ridges alongthe northeastern Gulf Coast-fact or fiction? Transactions of the Gulf Coast Association of GeologicalSocieties, 22, 223-228.
OTVOS, E.G., 1976. "Pseudokarst" and "pseudokarstterrains"-basic problems of terminology. Bulletin ofthe Geological Society of America, 87, 1021-1027.
OTVOS, E.G., 1978. New Orleans-south Hancock Holocene barrier trends and origins of Lake Pontchartrain.Transactions of the Gulf Coast Association Geological Societies, 28, 337-355.
OTVOS, E., 1981. Tectonic lineaments or Pliocene andQuaternary shorelines, northeast Gulf coast. Geology,9, ~398-·404.
OTVOS, E.G., 1990a. Subsurface evaluation of Mississippi coastal sediment units; comparison with Apalachicola area Quaternary sequence. [J. S. Bureau of Mines,Final Report #G-1194128, Miss. Mineral ResourcesInstitute, 74p.
OTVOS, E.G., 1990b. Mississippi and adjacent coastalsectors; geological and environmental perspectives. In:BURRAGE, D.D., (ed.), Long Term Implications of SeaLevel Change for the Mississippi and AlabamaCoastlines. Mississippi-Alabama Sea Grant Consortium et al., 57-68.
OTVOS, E.G., 1991. Quaternary geology of the Gulf ofMexico coastal plain (with DuBAR, J.R. and others).The Geology of North America. Geological Society ofAmerica DNAG Series, K-2, 583-610.
OTVOS, E.G., 1992. Quaternary evolution of the Apalachicola coast, northeastern Gulf Coast. QuaternaryCoasts of the United States: Marine and LacustrineSystems, SEPM Special Publication 48, p. 221-232.
OTVOS, E.G., in press, Mississippi Gulf Coast and Adjacent Areas, Geologic Evolution, Stratigraphy andCoastal Geomorphology. In: GOHN, G.S.; REINHARDT,J., and RUBIN, M. (eds.), Physical Stratigraphy andDepositional History of the Quaternary Sediments inthe USGS-Belle Fontaine No.1 Corehole, JacksonCounty, Mississippi, U.S. Geological Survey Bulletin.
OTVOS, E.G. and HOWAT, W.E., 1992. Late Quaternarycoastal units and marine cycles: Correlations betweennorthern Gulf sectors. Transactions of the Gulf CoastAssociation Geological Societies, 42, 571-585.
.Iournal of Coastal Research, Vol. 11, No.4, 1995
1002
PARKER, G.G., and COOKE, C.W., 1944. Late Cenozoicgeology of southern Florida. Florida Geological Survey Bulletin, 31, 1784-1800.
REINECK, H.E. and SINGH, LB., 1992, Depositional Sedimentary Environments. New York: Springer-Verlag,Second Edition, 549 p.
RUPERT, F.R., 1991. Geology of Gulf County, Florida.Florida Geological Survey Bulletin 63, 51.
SCHOVE, D.J., 1987. Sunspot cycles and weather history,p. 355-377. In: RAMPINO, M.R. and others, eds.), Climate, History, Periodicity, and Predictability. NewYork: Van Nostrand Reinhold Co., 588 p.
STAPOR, F.W., JR., 1973. Coastal Sand Budgets and Holocene Beach Ridge Plain Development, NorthwestFlorida. Florida State University, Tallahassee, Ph.D.Dissertation, 219 p.
STAPOR, F.W., JR., 1975. Holocene beach ridge plaindevelopment, northwest Florida. Zeitschrift fur Geomorphologic, Supplementband 22, 116-144.
STAPOR, F.W., JR. and OTHERS, 1987. Episodic barrierisland growth in southwest Florida: a response to fluctuating Holocene sea level, 149-202, Miami Geological Society Memoir, 3, 233p.
STAPOR, F.W., JR., and others, 1991. Barrier island progradation and Holocene sea-level history in southwestFlorida. Journal of Coastal Research, 7, 815-838.
TANNER, "V.F., 1966. Late Cenozoic history and coastalmorphology of the Apalachicola River region, westernFlorida. In: SHIRLEY, M.L. (ed.), Deltas. HoustonGeological Society, 83-97.
TANNER, W.F., 1991. Application of suite statistics tostratigraphy and sea-level changes. In: SYVITSKI,J.P.M. (ed.), Principles, Methods of Application ofParticle Size Analysis. Cambridge, etc.: CambridgeUniversity Press, pp. 283-292.
TANNER, W.F., 1992. Oversize oxbows: tentative dates,
Otvos
effects and risks. Transaction Gulf Coast Associationof Geological Societies, 42, 727-734.
TANNER, W.F., 1993a. Late Holocene sea-level changesfrom grain-size data: evidence from the Gulf of Mexico. The Holocene, 3, 249-259.
TANNER, W.F., 1993b. Louisiana cheniers: clues to Mississippi delta history. Deltas of the World. In: KAY,R. (ed.), Coastal Zone '93. American Society of CivilEngineers, pp. 71-84.
TANNER, W.F., 1993c, Louisiana cheniers: settling fromhigh water. Transaction Gulf Coast Association ofGeological Societies, 43, 391-397.
TERS, M., 1987, Variations in Holocene sea on the FrenchAtlantic coast and their climatic significance, p. 204237. In: RAMPINO, M.R. and others, (eds.), Climate,History, Periodicity, and Predictability. New York:Van Nostrand, 588p.
VAN ANDEL, TJ.H., 1981. Science at Sea. San Francisco:Freeman, 186 p.
WHITE, A.W., 1970. The geomorphology of the FloridaPeninsula. Florida Bureau of Geology Bulletin, 51,164p.
WILLARD, D.A. and EDWARDS, L.E., 1994. Palynomorphbiostratigraphy and paleoecology of subsurface upperNeogene and Quaternary sediments in southern Jackson County, Mississippi. In: GOHN, G.S.; REINHARDT,J., and RUBIN, M. (eds.), Physical stratigraphy anddepositional history of the Quaternary sediments inthe USGS-Belle Fontaine No.1 coreholes, JacksonCounty, Mississippi. U.S. Geological Survey Bulletin(in press).
WINKER, CH.D. and HOWARD, J.D., 1977. Plio-Pleistocene paleogeography of the Florida Gulf Coast interpreted from relict shorelines. Transactions Gulf CoastAssociation Geological Societies, 27, 409-420.
Journal of Coastal Research, Vol. 11, No.4, 1995