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This article was downloaded by: [University of Cambridge]On: 18 December 2014, At: 13:55Publisher: Taylor & FrancisInforma Ltd Registered in England and Wales Registered Number: 1072954 Registeredoffice: Mortimer House, 37-41 Mortimer Street, London W1T 3JH, UK
Australian Journal of Earth Sciences:An International Geoscience Journalof the Geological Society of AustraliaPublication details, including instructions for authors andsubscription information:http://www.tandfonline.com/loi/taje20
Discussion: History of coastal dunesat triangle Cliff, Fraser Island,QueenslandR. J. Coventry aa CSIRO, Division of Soils, PMB , PO Aitkenvale, Townsville, Qld,4814, AustraliaPublished online: 01 Aug 2007.
To cite this article: R. J. Coventry (1988) Discussion: History of coastal dunes at triangle Cliff,Fraser Island, Queensland, Australian Journal of Earth Sciences: An International GeoscienceJournal of the Geological Society of Australia, 35:4, 579-583, DOI: 10.1080/08120098808729473
To link to this article: http://dx.doi.org/10.1080/08120098808729473
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Australian Journal of Earth Sciences (1988) 35, 579-583
Discussion: History of coastal dunes at Triangle Cliff, Fraser Island,Queensland
R. J. Coventry
CSIRO, Division of Soils, PMB, PO Aitkenvale, Townsville, Qld 4814, Australia.
Ward and Grimes (1987), in their discussion ofthe stratigraphy of part of the western shore ofFraser Island, Queensland, presented a revisedQuaternary stratigraphy of a series of strandedbeach, aeolian dune and alluvial environments.They attempted to reconcile differences in theirwork published over the last decade (Ward1977a, b; Grimes 1979), and have reassessed thesignificance of radiocarbon dates available fromthe area.
This discussion focuses on difficulties indiscriminating some of the stratigraphic unitsnamed by the authors, in understanding therelative roles of waves and wind in depositingthe beach and dune components of the units andtherefore their associations with past sea levels,and in recognizing the relationships betweensome of the key stratigraphic units. In particular,an alternative explanation is proposed for therelationships of the Triangle Cliff dune sand, ofprobable Late Pleistocene or Early Holoceneage, which is now thought by Ward and Grimes(1987) to be a time-transgressive unit: under-lying and older than the Wathumba beach sandon the eastern side of the island but overlying,and therefore younger than the same beach sandat Triangle Cliff.
RECOGNITION OF STRATIGRAPHICUNITS
The critical factor in establishing a landscapehistory from Quaternary sequences is to recog-nize unequivocally the various stratigraphicunits involved. A morphostratigraphicapproach, in which stratigraphic units are recog-nized primarily on the basis of their geomorphicexpression, allows the recognition of grossrelationships within landscapes. In many recon-naissance surveys such units provide an over-view of key phases of landscape development.
Such an approach was adopted at FraserIsland by Ward (1977a, b) in which a 'working
legend' was prepared setting out a list ofinformal names for Quaternary stratigraphicunits then recognized at the island. Thissequence has been expanded to 17 morpho-stratigraphic units (Ward & Grimes 1987, table1) consisting of parabolic dune sands and beachsands. The latter have both a wave-built beachcomponent and a wind-built foredune com-ponent.
Ward and Little (1975) and Ward (1977a, b)indicated that soils and weathering charac-teristics of the sand bodies were used originallyto identify the various morphostratigraphicunits on Fraser Island and elsewhere in the dunesands of coastal southeastern Queensland.Thompson (1983), working on the six aeoliandune systems of the Cooloola sand mass on theQueensland mainland 30 km south of FraserIsland (Fig. la), has pointed out that the rate atwhich soil horizons develop in an individualdune is determined by the relative rates of waterentry, erosion, and/or sedimentation at any site.The morphology of any soil profile developed inthe sands of a parabolic dune depends, there-fore, on geomorphic position on the dune.Pickett et al (1984), working on a North Strad-broke Island dune, have also pointed out thatusing soil depth to calculate absolute ages ismeaningless, except in general terms. Quitemarked differences in soil development fromsiliceous sands to podzols (classification accord-ing to Stace et al 1968) may be represented onthe one dune within any dune system, and table1 of Thompson (1983) gives the range of soilsrecorded within the parabolic dunes atCooloola.
These soil and weathering criteria have notbeen defined for the 17 morphostratigraphicunits at Fraser Island. The data in table 1 ofWard and Grimes (1987), and in any of theauthors' previous work on Fraser Island, areinsufficient to allow the unequivocal recog-nition of the individual units they have estab-
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580 R. J. COVENTRY
Fig. 1 (a) Location map and the distribution of the Triangle Cliff dune sand in the Fraser Island-Cooloola area(Source: Ward & Grimes 1987). (b) Distribution of the Burwilla Soil Landscape within the aeolian dune landscapesof the Cooloola area (Source: Thompson & Moore 1984). (c) Distribution of the Triangle Cliff dune sand in theCooloola area (Source: Ward & Grimes 1987).
lished. For example, the Triangle Cliff and Gara-wongera dune sands are shown to have similardune forms, similar common soils, and over-lapping depths of bleached surface soils; likewisefor the Bribie and Poyungan beach sands. Theinidividuals forming these pairs of units cannotbe differentiated using the criteria of table 1 ofWard and Grimes (1987); other unpublishedinformation must be invoked.
Furthermore, the two soil criteria listed intable 1 of Ward and Grimes (1987) are notunique in denning morphostratigraphic units:
neither allows for the geomorphic control of theprofile morphology of soils on parabolic dunes(Thompson 1983), especially if the soils of anolder unit have been variably scoured or erodedto remove surface horizons prior to the deposi-tion of a younger unit. For example, how do theauthors distinguish between the sands on thedune floor of an active or recent parabolic duneand the 'unweathered' sands of an eroded, olderdune immediately underlying it?
The authors have failed to provide thecritically important information needed in any
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HISTORY OF COASTAL DUNES, FRASER ISLAND 581
reassessment of the Quaternary stratigraphicunits of Fraser Island: that is, a proper definitionof those units that will permit their unequivocalrecognition. Mere assertions of the kind that'The sand above Soil B is Triangle Cliff dunesand' (Ward & Grimes 1987, p. 329) are inade-quate when the specific characteristics of thevarious units have not been defined even after adecade of work in the area.
BEACH AND DUNE SANDS
It is only in their Abstract and in a footnote totable 1 that Ward and Grimes (1987) haveacknowledged that the 'beach sands' include anaeolian foredune component. Differentiation ofthe wave-built and wind-built components isessential in any palaeoenvironmental recon-struction involving past sea levels. In none oftheir publications on Fraser Island have theauthors shown how they have discriminatedthese components. The morphological criteriaused by Ward (1977a) for reconnaissancemapping would appear to be inappropriate toallow the separation of stratigraphic units withinan exposure where the sedimentological, soil,and weathering characteristics of the units aremore important than their geomorphic forms.Yet no particle-size data from Fraser Island havebeen presented by the authors, although suchhave been used effectively elsewhere todiscriminate beach and dune environments (e.g.Mason & Folk 1958; Friedman 1961; Chappell1967; Hails 1967).
The question remains: how did the authorsdetermine the elevation to which wavesdeposited sediments forming what they recog-nize as the Wathumba beach sand? Because thisunit is defined as a 'beach sand' as opposed to a'dune sand', it seems reasonable to infer thatsome of the sediment was deposited by wavesrather than by the wind. Ward and Grimes(1987, fig. 3) show the Wathumba beach sand tobe 8-16 m thick and the altitude of its uppersurface to lie at elevations of 12-21 m. Accord-ing to their text and fig. 3, this beach sand over-lies Bed T (not in the reverse order as shown intheir table 2) which rises 2 m above the modernbeach and is thought by Ward and Grimes(1987, p. 328) to be related to a postglacial sealevel of about +1 m relative to the present.Clearly, then, the wave-deposited component of
the Wathumba beach sand marks a higher andyounger strandline. The altitude at which thosewaves were effective then determines themaximum postglacial sea level recorded in thesediments at Triangle Cliff.
RELATIONSHIPS OF KEY UNITS
Bed T and Woorim beach sand
A previously published correlation between BedT and the Woorim beach sand is rejected in threeplaces by Ward and Grimes (1987, pp. 326,330,and 331), yet they have not stated why. The twounits appear to occupy the same geographic andstratigraphic positions in fig. 3 of Ward andGrimes (1987) and fig. 2 of Grimes (1979); theirunique sedimentological, soil, and weatheringcharacteristics, which may be the basis of theirdiscrimination, are not set forth. It would seemthat the two units are known to the authors tooccur separately elsewhere. Insufficientinformation has been presented by Ward andGrimes (1987) to show why the former correla-tion is now rejected, or to suggest possible cor-relations of the Woorim beach sand with othermorphostratigraphic units at Fraser Island.
Triangle Cliff dune sand
Ward and Grimes (1987, fig. 1) have mapped thedistribution of the Triangle Cliff dune sand inthe Cooloola sand mass area. Although the scaleis small, two of the three occurrences appear tocorrespond fairly closely with the distribution ofthe 'Burwilla Soil Landscape' of Dune System 3of Thompson and Moore (1984) (Figs lb, c ofthis paper). Three areas of the Burwilla SoilLandscape towards Double Island Point havenot been included by Ward and Grimes (1987)who mapped a small area of Triangle Cliff dunesand about half-way between Double IslandPoint and Teewah.
Ward and Grimes (1987) apparently believethe Triangle Cliff dune sand to have some, butnot all, characteristics in common with theBurwilla Soil Landscape. The soils literaturesuggests that the degree of soil profiledifferentiation in the Triangle Cliff and Burwillaunits is comparable. If the Quaternary unitsrecognized in similar sandy sediments at FraserIsland are to have any significance in the
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582 R. J. COVENTRY
establishment of regional landscape histories,then the units must be so denned as to berecognized clearly and unambiguously in thenearby Cooloola area and throughout theregion.
The source of this problem may lie largely inthe definition of the Triangle Cliff dune sand.The unit labelled TC'm the Triangle Cliff section(Ward & Grimes 1987, fig. 2) appears to be aremnant of a morphostratigraphic unit olderthan that forming the large parabolic dunelabelled t in the same figure. On the north-western flank of the large parabolic dune (dueeast of a') an unconformity is shown between thetwo units of apparently different age. Thissuggests that the two units, recognized as the'Triangle Cliff dune sand' by Ward and Grimes(1987), have not been deposited as a single,parabolic dune. Hence the 'Triangle Cliff dunesand' exposed at the western shore of FraserIsland at Triangle Cliff (Ward & Grimes 1987,fig. 3) may not necessarily be the same unit asthat forming the large parabolic dune thatoccupies the central portion of fig. 2 of Ward andGrimes (1987). The large parabolic dune,migrating towards the northwest, appears tohave overridden and buried the older unitrecognized in fig. 3 of Ward and Grimes (1987)as the 'Triangle Cliff dune sand' at TriangleCliff. Such an interpretation leads to theconclusion that the 'Triangle Cliff dune sand' isnot necessarily a time-transgressive unit assuggested by Ward and Grimes (1987, pp.331-332), but might consist of two separateunits, one underlying the Wathumba beach sandat Hook Point on the eastern shore of FraserIsland (Ward & Grimes 1987, fig. 4), and theother overlying the same beach sand at TriangleCliff in the west.
CONCLUSIONS
Although the history of the coastal sand massesof southeastern Queensland has been studied bythe authors and others for some considerabletime, the basic geological and pedological dataused to discriminate amongst Quaternary strati-graphic units have not yet been presented.Failure to define the field and/or laboratorycriteria used to identify, map, and differentiatethe various sand bodies, and their beach anddune components, leaves this reader (and per-haps future workers) still unable to recognize
and discriminate among the 17 morphostrati-graphic units named by Ward (1977a, b) andrevised by Ward and Grimes (1987) at FraserIsland. Until the essential criteria for the recog-nition of the various Quaternary units aredescribed, little is achieved by attempting toreconcile previously published, divergent viewsconcerning the interpretation of the TriangleCliff section.
REFERENCESCHAPPELL J. 1967. Recognizing fossil strand lines
from grain-size analysis. Journal of SedimentaryPetrology 37, 157-165.
FRIEDMAN G. M. 1961. Distinction between dune,beach, and river sands from their textural charac-teristics. Journal of Sedimentary Petrology 31,514-529.
GRIMES K. G. 1979. Carbon-14 dates and theevolution of Fraser Island. Queensland Govern-ment Mining Journal 80, 79-82.
HAILS J. R. 1967. Significance of statistical parametersfor distinguishing sedimentary environments inNew South Wales, Australia. Journal of Sedi-mentary Petrology 37, 1059-1069.
MASON C. C. & FOLK R. L. 1958. Differentiation ofbeach, dune and aeolian flat environments by sizeanalysis, Mustang Island, Texas. Journal ofSedimentary Petrology 28, 211-226.
PICKETT J. W., THOMPSON C. H., MARTIN H. A. &KELLY R. A. 1984. Late Pleistocene fossilsbeneath a high dune near Amity, North Strad-broke Island, Queensland. In Coleman R. J.,Covacevich J. and Davie P. eds, Focus on Strad-broke, pp. 167-177. Boolarong Publications,Brisbane.
STACE H. C. T., HUBBLE G. D., BREWER R. et al 1968.A Handbook of Australian Soils. Rellim TechnicalPublications, Glenside, SA.
THOMPSON C. H. 1983. Development and weatheringof large parabolic dune systems along the sub-tropical coast of eastern Australia. Zeitschrift furGeomorphologie Supplementband 45, 205-225.
THOMPSON C. H. & MOORE A. W. 1984. Studies inlandscape dynamics in the Cooloola-Noosa Riverarea, Queensland. 1. Introduction, generaldescription and research approach. CSIRO Aus-tralia, Division of Soils, Divisional Report 73.
WARD W. T. 1977a. Sand movement on Fraser Island:a response to changing climates. OccasionalPapers in Anthropology 8,113-126. AnthropologyMuseum, University of Queensland.
WARD W. T. 1977b. Field excursion from OrchidBeach to Triangle Cliff and Lake Bowarrady. InDay R. W. ed., Field Conference 1977, Guide-book, pp. 65-71. Geological Society of Australia,Queensland Division, Brisbane.
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HISTORY OF COASTAL DUNES, FRASER ISLAND 583
WARD W. T. & GRIMES K. G. 1987. History of coastaldunes at Triangle Cliff, Fraser Island, Queens-land. Australian Journal of Earth Sciences 34,325-333.
WARD W. T. & LITTLE I. P. 1975. Times of coastal
sand accumulation in south-east Queensland.Proceedings of the Ecological Society of Australia9, 313-327.
(Received 15 April 1988; accepted 20 May 1988)
Australian Journal of Earth Sciences (1988) 35, 583-587
Reply to discussion: History of coastal dunes at Triangle Cliff,Fraser Island, Queensland
W. T. Ward1 and K. G. Grimes2
lCSIRO Division of Soils, Cunningham Laboratory, 306 Carmody Rd, St Lucia, Qld 4067,Australia.
2Geological Survey of Queensland, QMEC House, Mary St, Brisbane, Qld 4000, Australia.
The differences in viewpoint that Ward andGrimes (1987) try to reconcile relate to carbondating of Bed T and to the relationships of Bed Tto Triangle Cliff dune sand and Wathumbabeach sand. Their conclusion is that TriangleCliff dune sand and Wathumba beach sand arein part contemporary.
Coventry proposes another explanation butobscures the issue by devoting most of his text toa discussion of problems he associates withrecognizing morphostratigraphic units and sealevels in relation to dune and beach sands. Hisarguments here are with Ward (see referencesbelow), although Grimes is under fire simplybecause the authorship of table 1 in Ward andGrimes (1987) was not clearly indicated. Themore general topic is discussed first.
RECOGNITION OFMORPHOSTRATIGRAPHIC UNITS
The following text is by Ward. Grimes is notnecessarily in agreement.
Coventry argues that the morphostratigraphicunits are not properly defined or supported bysufficient data to permit their unequivocal
recognition. He concludes that attempts toreconcile differences are in these circumstancesa waste of time. I do not agree.
Coventry's view appears to be the conse-quence of a fundamental difference between usin our understanding of morphostratigraphy. Heseems to believe that units are recognized byreference to criteria. I believe that they aredefined by geomorphological discontinuities.These discontinuities show that the units have areal existence and are not merely arbitrarydivisions of a continuum. Table 1 in Ward andGrimes (1987) does not list criteria, as Coventrypresumes, but shows dune forms, common soilsand depths of the bleached surface zone that aretypical of each unit. The paper provides adetailed description of the units occurring atTriangle Cliff, a block diagram and, as in otherpapers cited below, a section and map. I find itdifficult to believe that any other information isneeded. An avalanche of description does notmake for greater validity.
It is not true that morphostratigraphic unitsrepresent gross relationships in landscapes orprovide overviews in preliminary surveys, asCoventry claims. They are widely accepted byQuaternary geologists because they provide
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