Plant fossil distributions in some Australian Permian non-marine sediments

Sedimentary Geology. 85 (1993) 601-619 Elsevier Science Publishers B.V., Amsterdam

601

Plant fossil distributions in some Australian Permian non-marine sediments Stephen McLoughlin Department of Geology, University of Western Australia, Nedlands, W.A. 6009, Australia

Received June 30, 1992;revised version accepted November27, 1992

ABSTRACT McLoughlin, S., 1993. Plant fossil distributions in some Australian Permian non-marine sediments. In: C.R. Fielding (Editor), Current Research in Fluvial Sedimentology. Sediment. Geol., 85: 601-619. Plant remains occur in all post-Devonian, lowland, terrestrial depositional systems, with distinctive assemblages characterizing discrete environments. Glossopterid gymnosperms dominate most Australian Permian coal-bearing sediments. Herbaceous pteridophytes, sphenophytes, and lycophytesare best represented in lower deltaic lacustrine and paludal deposits. Non-glossopterid gymnosperms mostly colonized drier floodplain and upland environments and are poorly represented in Australian Permian sequences. Fresh- and brackish-water algae are abundantly preserved in paludal and lacustrine facies in both alluvial and delta plain environments. Seasonal productivity and taphonomic factors undoubtedly influenced the composition of interseam compression/impression floras but integration of information from these assemblages with that from permineralized peats, in-situ coalified plants, and coal maceral and palynologicalanalyses can assist in the interpretation of Australian Permian coal-formingenvironments and the structure of plant communities.

Introduction Though ichnofossils and terrestrial animals are occasionally recorded (Pollard, 1988), macroscopic and microscopic plant remains are frequently the only fossils preserved in fluvial depositional systems. The anatomical adaptations, preservation, and distribution of plants are often very valuable for detailed palaeoenvironmental interpretations of such sedimentary sequences. Coal-balls, with calcareous, permineralized, anatomically preserved plant remains, are absent from Australian Permian coals, so floral distributions in continental sediments must rely on analyses of compression/impression floras, scarce silicified peat deposits, coal maceral distribution, ~alynological studies, and analogies with modern terrestrial ecosystems. Analyses of Australian Permian coal-forming plant communities are not yet available on the scale of some Northern Hemisphere studies (e.g., Scott, 1979; Phillips et al., 1985; DiMichele and Phillips, 1988; Miao et

al., 1989). Fielding (1985) discussed criteria for discriminating between delta plain and alluvial plain deposits particularly emphasizing the diagnostic value of coal seam geometries. Moore (1987) has established standardized terms for the identification of modern peat-forming communities based on their hydrology and dominant vegetation type. This paper aims to briefly outline generalized distributional trends of plant groups within Australian Permian alluvial and delta plain sediments, as illustrated by previous palaeobotanical systematic surveys and highlighted by four case studies, in order to enhance their value for future interpretation of coal-forming depositional environments.

Climatic setting

Australia was situated in high latitudes (55 ° 80 °) during the Permian (Embleton, 1984) and experienced conditions ranging from glacial (in

0037-0738/93/$06.00 © 1993 - Elsevier Science Publishers B.V. All rights reserved

UWA116629. ttarris Sandstone. Carnarvon Basin, Pref'Lxes 'UQF', "UWA. and "WAM" refer ~o tossil catalogue numbers in the respective institutions: Department of Earth Science,. Universib of Oucenskmd. Brisbane: Department of Geology. University of Western Australia, Perth: aJ~d Western Australian Museum, Perth.

Fig. 1. Representative plant megafossils from Australian Permian non-marine sediments. (A) Sphenophyllum rhodesii Rigby, x 1.9, UWA115397, Irwin River Coal Measures, P,~;'th Basin. (BI Sphenophytlum morganae MeLoughtin, x 1,3. UWA115380, Irwin River Coal Measures, Perth Basin. (C) Schizoneura gondwanensis Feistmantet x 0.6, UQF79150, Rangal Coal Measures~ Bowen Basin. (,D) Raniganjia minima Rigby, ×2.9, UWA115665, Collie Coal Measures, Collie Basin. (E) Walkomiella austratis (Feistmantet'l Florin, × 1.5, UWA45814, Newcastle Coal MeasureS, Sydney Basin. (F, GiVertebraria it~dica Royle: iF) UQF79671, × 1.5, transverse section of permineralized axis showing internal chambers, MacMillan Formation, B0wen Basin; (G) UWAl16630, x0.7, horizontal impression, Collie Coal Measures, Collie Basin. (H) Cordaites spatulata (Dana) Rigby, Maheshwari and Schopf, × 1.5, WAM.P69.50, Wagina Sandstone, Perth Basin. (1) Glossopter~s burngrouensi~ McLoughlin (broad-meshed leaf), ;<0.7, UQF79233, Baralaba Coal Measures, Bowen Basin. (J) Phyttotheca austrMis Brongniart emend Townrow, ×0.7, UQF79141, Rangal Coal Measure~, Bowen Basin. (K) Dichotomopteris lindlcyi (Royle) Maithy. x0.7, UQF79175, Burngrove Formation, Bowen Basin. (L) Lycopod axis impression, ~<0."7.

'-r rz

7

~r

PLANT FOSSIL DISTRIBUTIONS

IN S O M E A U S T R A I A A N P E R M I A N N O N - M A R I N E

SEDIMENTS

603

living in waterlogged substrates (Spicer, 1989). Distinctive suites of in-situ and transported plants characterize discrete environments within virtually all Australian Permian fluvio-deltaic deposits (Retallack, 1980; Draper and Beeston, 1985). Although species assemblages differ from Early to Late Permian, the major plant groups display consistent environmental preferences.

the Asselian) to cool temperate (in the Lopingian) based on invertebrate faunas (Dickins, 1978). Arborescent hydrophytic glossopterids dominated the post-glacial Gondwanan Permian vegetation which was markedly less diverse than coeval warm temperate to tropical Euramerican and Cathaysian floras (Retallack, 1980). Glossopterids show various adaptations and responses to high-latitude, wet, lowland environments. A deciduous habit is suggested by the frequent occurrence of repetitive mats (autumnal banks) of well-preserved leaves (Plumstead, 1969). Prominent seasonal growth banding is a characteristic feature of glossopterid woods (Maheshwari, 1972). Vertebraria axes (Figs. 1G, 1F), the roots of glossopterid plants (Gould, 1975; Gould and Delevoryas, 1977), have internal chambers which probably performed an aeration function for plants

Tectonic setting Coal measures occur in most Australian Permian basins (Fig. 2) in a variety of tectonic settings. Coals are most extensively developed in the B o w e n - G u n n e d a h - S y d n e y foreland basins, with additional significant accumulations in the associated Galilee and Cooper pericratonic basins (Veevers et al., 1982; Veevers, 1984). On the

(3 Bonaparte Basin Basin Bowen Basin

Basin Pedirka~ Basin t ~

Basin I

GREATER INDIA

~

Officer Basin

l Perth ~Basin

~'~ Gympie

C°~inPe ~ ~

Arckaringa Basin

Collie

G Basin r Sydney Basin

_/[NEw

ZEALAN[ AND LORD

ANTARCTICA N I

t °

500

1000

I

I

1500km I

tl

RISE

Tasmania Basin

Fig. 2. Distribution of Australian Permian basins (after Cooper, 1983) showing locations of study areas: R - Blackwater (Ranga Coal Measures), C = Colinlea Sandstone type section, E = Western Collieriesopencut No. 3 mine (Ewington Member, Collie Coa Measures), I = Irwin River (Irwin River Coal Measures).

604

,% M C L u L I ( } H L I N

western side of the continent, Permian sediments of the Bonaparte and Canning Basins (formed as extra-arch basins behind a single rifted arch) together with the Carnarvon and Perth Basins (rift valley settings) are less rich in coals than the eastern basins (Veevers et al., 1982; Veevers, 1984). Other significant depocentres (Officer, Arckaringa, Pedirka, Blair Athol, and Collie Basins) represent thin but broad epicratonic basins or Environment Thickness Lithology

small graben or half-graben complexes (Veevers. 1984) with variable coal measure development. Representative coal measures Four rock units were selected from different coal-bearing, non-marine, depositional settings and examined to determine their fossil content. Graphic logs of representative sections were con-

Fossils & sed. structures

(m)

Key to symbols

-KX-X'X LA ~?XN--X LA

1, .!i!ii!iliiiiZi!L!i!i!iiL

Lenticular finegrained sandstone

12 q ~ i : i : ! : : : : : : : : ; : : \ ~?X-X-XLA "! !~!~!~!~!~!~!~!~i~!i!~-!~J . . ~ - - , - ~ -SSN-XLA i~.L~i.;i.;-:.:L~L~:.5.::~L:..~"i ~ \ ' - \ \ LA 11 - !:::~iliiii::~il!;::~::iil} \ \ x \ LA ............... \'-'-', LA i!~!.~!~.!.."!.~!~!,!!,.:!..:i~i,L, . -~N~LA

Sandstone Pebbles Cross-bedding: Pplanar, L- low angle

,0

LA Channel & bar deposits

Undulating laminae ~Erosional

lii;iiiSiiii

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Current lenticular bedding Current ripple cross-lamination Current/wave ripple cross-lamination

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iiiiSiSliiilSiiiiii::~[ ~ -,-.....,,,,..,.-

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P

,,,

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Convoluted bedding

i.':.~,iii iii iii !i !i::i i i ..,,.....,,,.,,

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surface

-N-XX~ P

,.,

-?3 Load casting Glossopteris spp.

Backswamp & ox-bow lake deposits + sporadic flood sands

Cordaites sp. 4

~ ~ _ . ~ _ _ "

I ~

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222., 3

~ ~ ~ , - d

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tED Axis impressions Glossopterid roots (Vertebraria)

t ~ eg

Burrows

2

Channel & bar deposits

1

:i:[:i:[: : :~::.~

Clay Silt

Sand

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I

I

Gran. Peb.

I

Fig. 3. Graphic sedimentologicallog of a lower part of the Colinlea Sandstone (early Late Permian) type-sectionexposed along the Tambo Road, 26 km west of Springsure, Springsure Shelf, central Queensland. Cordaitanthalean and glossopterid foliage and root remains are most abundantly preserved in abandoned channel and upper bar deposits within this alluvial plain setting.

PLANT FOSSIL DISTRIBUTIONS IN SOME AUSTRALIAN PERMIAN NON-MARINE SEDIMENTS

structed to illustrate the characteristic variety and distribution of fossils within these sequences. Information from other palaeobotanical studies was incorporated to assess the palaeoenvironmental preferences for particular plant groups.

Colinlea Sandstone (allueialplain ent,ironments) The Kungurian-Guadalupian Colinlea Sandstone is distributed as a broad sheet across the Springsure Shelf linking the Bowen and Galilee Basins in Queensland. The unit contains only very thin and sporadic coals and is a more proxiDEPOSITIONAL ENVIRONMENT

COAL SEAM

LITHOLOGY

605

mal correlative (in part) of the gas-producing fluvio-deltaic Aldebaran Sandstone to the east. The Colinlea Sandstone rests unconformably on Early Permian sedimentary rocks or D e v o n i a n Carboniferous metasediments of the Drummond Basin. Much of the unit is poorly exposed but certain road cuttings in the type area reveal excellent sections through fluvial deposits which yield abundant plant macrofossils (Fig. 3). Two principal facies are developed in this area: channel sandstones, and shale- or siltstone-dominated overbank deposits. The channel facies consists of KEY

FOSSILS & SED. STRUCTURES

Nakina Formation (Tertiary)

Coal

18m Channel & bar sands with minor overbank shales and coal

Shale Siltstone

16

Interlaminated shale & sandstone Sandstone

14 Cross-bedding Flat laminae

12 Forest swamp Lacustrine/marsh Forest swamp Lacustrine/marsh Forest swamp Lacustrine/marsh Forest swamp

Moira

Erosional surface ~

10 Stockton

Fragmentary leaves and fusain

~

Glossopterisleaves

~

Lycopod leaves

~

Cordaitesleaves

8 Wallsend 4 Homer

~

Lacustrine/marsh 0

--t Clay

S i l t Sand Gran.

Coalified gymnosperm? axes Lycopod axes Roots

Fig. 4. Graphic sedimentologicallog of part of the coal-rich Early Permian Ewington Member (,alluvial plain environment), Collie Coal Measures, exposed in Western Collieries opencut No. 3 mine, Collie Basin, Western Australia. Note abundant Cordaitesand Glossopterisleaves in lacustrine shales, and root-bearing horizons underlyingcoals.

606

relatively uniform fine- to coarse-grained low-angle or tabular cross-bedded quartzose and micaceous sandstone. Sandstone cross-bed sets commonly show erosional bases and possess a thin and sparse basal lag of < 2 cm diameter intraformational shale or extraformational quartz clasts. Water-escape structures are sporadically evident, conglomerates are rare, and the facies hosts only sparse fragmentary wood impressions, burrows, and root traces (Fig. 3). The overbank facies consists of finely laminated shale and siltstone interbedded with thin (< 10 cm), discontinuous, cross-laminated, finegrained, sandstone beds. This facies is represented by deposits up to 3 m thick overlying channel sandstones with an erosional contact. The units are lensoid in cross-section and grade laterally into thinly interbedded fine-grained sandstone and siltstone. Thin (< 20 cm) impersistent siltstones, sporadically distributed conformably between the channel sandstones, are also representative of the overbank facies. The shale and siltstone facies probably represents backswamp and abandoned channel fill. This facies hosts abundant plant remains in the form of leaf, seed, wood, and root impressions (moulds). Glossopteris species dominate the assemblages and the abundance of aerenchymatous roots (Vertebraria) suggests that these plants were growing in, or immediately adjacent to, riverine and shallow lacustrine environments and extending their roots into the underlying waterlogged sediments. No upright trunks were observed. The presence of matted (autumnal?) leaf banks regularly interbedded with sand lenses within this facies probably indicates repeated small-scale (seasonal?) flooding episodes. The greatest proportional representation of cordaitanthaleans (Fig. 1H) within Australian Permian terrestrial strata is found in alluvial fan and alluvial plain deposits, especially those in small intracratonic basins and along the cratonic flanks of the major basins (Figs. 3, 4; Draper and Beeston, 1985). The occurrence of Cordaites in the Colinlea Sandstone (Fig. 3) supports interpretation of this unit as a proximal fluvial (alluvial plain) deposit receiving organic contributions from upland plant communities. Some Eurameri-

s. M ( ' I ~ ) U G H L I N

can Cordaites species adopted mangrove-like habits (Raymond and Phillips, 1983) but the abundance of Gondwanan forms in alluvial plain environments suggests an alternative habitat niche for the southern species. Conifers (e.g., Walkomiella: Fig. I E) were probably also important elements of upland and well-drained environments in the Australian Permian. Their remains are best represented in sediments along the western flank of the Sydney Basin and in isolated (intermontane?) basins (Retallack, 1980; Rigby, 1993). Conifers probably colonized non-depositional sites on the Permian highlands and were only incorporated m alluvial environments on the margins of the broad basinal lowlands (Retallack, 1980). South American Permian conifers are more diverse and have been reported from a range of lowland environments (Archangelsky, 1981), although they are especially well-represented in sediments flanking highlands (Archangelsky and Cfineo, 1987). Few pteridosperms (apart from glossopterids which are sometimes included in this group) are known from the Australian Permian probably owing to their preference for habitats not conducive to the preservation of their detached parts. Botrychiopsis, an index genus for latest Carbonif~erous to Early Permian strata (Rigby, 1983), wa,~ probably a stunted pioneering plant sparsely colonizing alluvial fans and riverine environments following the retreat of the Gondwanan ice cap,~ (Retallack, 1980). Blechnoxylon talbragarense. recorded from a single conifer-rich assemblage in the Illawarra Coal Measures on the western margin of the Sydney Basin (Etheridge. 1899), presumably preferred upland habitats peripheral to the basin (Retallack, 1980) and contributed little vegetable matter to lowland coal-forming environments. Bergiopteris is sporadically represented in tuff deposits of the Nychum Volcanics. north Queensland (Rigby, 1993), lacustrine facies of the Reids Dome Beds, Bowen Basin (Draper and Beeston, 1985), and overbank shales within the strongly fluvial Wagina Sandstone, Perth Basin (= Gondwanidium in Rigby, 1966). Vertebraria is a prominent constituent of silicifled peat (mire) deposits in Australia and Antarctica (Schopf, 1970; McLoughlin, 1992a, Webb and

PLANT FOSSIL DISTRIBUTIONS IN SOME AUSTRALIANPERMIANNON-MARINESEDIMENTS

Fielding, 1993). Vertebraria is also very abundant as impressions in marginal lacustrine and levee deposits and is often associated with mottled palaeosols underlying coal seams (Fig. 4). Cazzulo-Klepzig et al. (1980) portrayed glossopterids

607

as marginal marine mangrove-like plants on the basis of Glossopteris leaves found in association with marine invertebrates. However, such co-occurrences are rare and the overwhelming abundance of glossopterid remains in alluvial plain

TABLE 1 Summary of the distribution of plant fossils in Australian Permian alluvial plain and deltaic sediments Plant group

Alluvial plain

Upper delta plain

Lower delta plain

Glossopterid foliage

Abundant in ribbon-like paludal and overbank facies adjacent to channels,

Abundant in extensive paludal, lacustrine, and floodplain settings.

Locally abundant in paludal and lacustrine facies.

Glossopterid roots

Common in levee, abandoned channel, and floodplain environments. Associated with poorly developed palid palaeosols.

Very abundant (as for alluvial plain). Often underlie extensive coal seams.

Locally abundant in point bar and levee deposits.

Other gymnosperm foliage

Common in lacustrine, abandoned channel and floodplain environments especially near margins of large basins and in small intracratonic basins.

Sporadic; occasionally found in extensive lacustrine facies.

Infrequent.

Reed-like sphenophytes

Locally common in lacustrine, bar, and abandoned channel facies.

Abundant; often in dense mats; sometimes in situ with flattened sub-parallel axes in lacustrine, paludal, and floodplain environments.

Locally abundant in lacustrine and paludal facies. Horizontal rhizomes common in palaeosols.

Broad-leafed sphenophytes

Occur rarely in backswamp deposits.

Sporadic in backswamp and floodplain environments.

Common in lacustrine paralic settings.

Lycophytes

Arborescent forms sporadic in paludal and alluvial fan facies. Rare in channel and welldrained floodplain environments in Australia, common in South America.

Rare.

Herbaceous forms sporadic in paralic sediments.

Ferns

Macrofossils rare, meiospores abundant and diverse.

Common in paludal and lacustrine facies. High diversity of meiospores.

Common in paludal, lacustrine, and paralic facies.

Gymnosperm axes

Abundant in channel and paludal settings, typically aligned transverse and parallel to palaeocurrent.

Common in channel, lacustrine, and paludal settings; rarely upright stumps in floodplain environments.

Common (though generally of smaller size or fragmentary) in channel, paludal, and adjacent marine environments.

Algal colonies/cysts; acritarchs

Sporadic to abundant in lacustrine and paludal facies. Typical genera: notryococcus, nra-

Often abundant in lacustrine and paludal facies, sometimes forming oil shales. Taxa as for alluvial plain.

Common (as for upper delta plain) with frequent addition of spinose marine acritarchs (e.g. Micrystridium and Veryhachium spp.).

( Vertebraria)

(Phyllotheca)

zilea, Orculisporites, Maculatasporites, eeltacystia, Portalites, Tetraporina.

and

608 and upper deltaic deposits (Figs. 3, 4, 6), the association of Vertebraria with well-developed palaeosols and peats, and the low sulphur and boron contents of many of the glossopteridbearing coals suggest that these plants colonized freshwater mires and riparian habitats.

Ewington Member, Collie Coal Measures (restricted alluvial plain environments) The Artinskian Ewington Member is the basal sub-unit of the Collie Coal Measures, Collie Basin (Fig. 2), and represents a 60-80 m thick fluvial deposit within a restricted (graben and halfgraben) alluvial plain setting (Lowry, 1976). The Ewington Member conformably overlies the glacigenic Stockton Formation. The coals of the Collie Coal Measures represent Western Australia's principal resource for electricity generation. Park (1982) described the facies relationships of the upper part of the Collie Coal Measures (Muja Member) in terms of a braided river fluvial model. A similar depositional setting appears to be applicable to the Ewington Member. The bulk of this unit comprises thick packages of

s, M£'I.()UGHLIN trough and planar cross-bedded, medium- to very coarse-grained quartzose to arkosic sandstone representative of channel deposits. The sandstones host abundant fragmentary coalified woody axes, whereas thin intervening carbonaceous siltstones yield detrital glossopterid and other gymnosperm foliage and stem remains. The middle part of the Ewington Member contains a series of economic coal seams (Fig. 4). The coals are typically underlain by mottled siltstones with abundant root impressions. Only fragmentary macrofossils (leaves and wood or fusain) are evident within the coals due to homogenization during the coalification process but the abundance of organic matter together with the presence of underlying glossopterid root-bearing beds suggests a forest swamp (or carr) community (sensu Moore, 1987). Glossopterid leaves are assigned to several genera and constitute the most abundant fossil remains in the Gondwanan Permian occurring in all alluvial plain and deltaic depositional environments (Table 1). Draper and Beeston (1985) found that gtossopterids dominated plant assemblages from all depositional environments (apart from coal-producing mires)

Fig. 5. Thin-sectionof siliceouspermineralizedpeat fromthe BurngroveFormation(Late Permian), BowenBasin showingstacked Glossopteris leaves(G) and rootlets(R). Scaleis 1 mm.

PLANT FOSSIL DISTRIBUTIONS IN SOME A U S T R A L I A N PERMIAN NON-MARINE SEDIMENTS

encountered in the Early Permian Reids Dome Beds of the Bowen Basin. Coals of the Reids Dome Beds were considered to be richest in sphenophyte remains although palynological data also suggested important contributions by ferns and gymnosperms. Attribution of coal macerals to specific plant taxa has limitations given our present knowledge of the megafloras, although broad-category maceral and coal microlithotype distributions have proved useful aids for interpreting depositional environments in Australian Permian and Cretaceous coal measures (Smyth, 1989; Struckmeyer and Felton, 1990). Although the absence of coal balls from the Australian Permian prevents extensive quantitative analyses of the constituents of the coal-forming vegetation, glossopterids probably contributed voluminous organic matter to the coal mires based on their abundance in sparse silicifled peats (Fig. 5). Gondwanan coals are additionally rich in resin-, wax-, and wood-derived macerals (Shibaoka and Smyth, 1975) largely derived from gymnosperms. Repetitive vitrinite and cutinite banding in Permian coals (Beeston, 1983) is reminiscent of stacked glossopterid leaves evident in silicified peats (Fig. 5) and Plumstead's (1969) autumnal leaf banks. The Ewington Member coals are typically overlain by siltstones containing abundant wellpreserved glossopterid, Cordaites, and lycopod leaf and axis compressions. The thinly laminated nature of the lithology and the fine preservation of the plant remains suggest that this facies represents deposition within low-energy lacustrine or marsh conditions drawing a regular input of organic matter although of insufficient quantity to generate peat. Repetition of the coal and siltstone facies indicates successive drowning and re-establishment of forest swamp communities. Contemporaneous faulting during deposition of the Collie Coal Measures (Park, 1982) may have controlled the positioning of the main palaeochannels and promoted stacking of overbank coal-producing facies in a ribbon-like belt flanking the main fluvial axis within this basin. The frequency of Cordaites leaves but dearth of herbaceous ferns and sphenophytes in the Ewington Member (as in the case of the Colinlea Sand-

609

stone) suggests a proximity to basin-margin communities. Australian Permian lycophytes (Rigby, 1966; Townrow, 1968; Beeston, 1990) were mostly herbaceous plants, and like their modern counterparts, probably grew in mires, lake margins, and in the moist understory of forests. Detached lycopod microphylls are locally abundant in lacustrine shales overlying coal seams in the Collie Coal Measures (Fig. 4). Similarly Draper and Beeston (1985) found the herbaceous Cyclodendron leslii Kr~iusel to be virtually restricted to lacustrine facies in the Reids Dome Beds, Bowen Basin. In South America, where slightly warmer climates prevailed during the Permian, arborescent lycopod logs are common in fluvial channel deposits and in-situ stumps occur in associated wet floodplain environments (Archangelsky, 1981; Cfineo and Andreis, 1983; Azcuy et al., 1987). Smaller (5-10 cm diameter) shrub-sized to arborescent lycopod axes (Fig. 1L) are preserved in the fluvio-deltaic, latest Carboniferous or earliest Permian, Harris Sandstone in the Carnarvon Basin, Western Australia (Read et al., 1973). Plant assemblages of Australian Permian alluvial plain deposits are thus dominated by glossopterid gymnosperm remains with significant contributions by non-glossopterid gymnosperms, sporadic representation of shrub- to tree-sized lycopods, and sparse occurrences of herbaceous ferns, sphenophytes, and lycophytes (Table 1).

Rangal Coal Measures (upper delta plain to allut'ial plain ent,ironments) The Rangal Coal Measures and their correlatives (Bandanna Formation and Baralaba Coal Measures) extend throughout much of the Bowen Basin and contain some of Queensland's principal coal resources. These Late Permian (Lopingian) units overlie tuffaceous shale-dominated marine and lacustrine formations and are conformably overlain by the Early Triassic fluvial Rewan Group implying intermediate (deltaic to alluvial plain) depositional settings for the coal measures (Mallett, 1983). Spinose acritarchs are infrequently recovered from the Rangal Coal Measures and equivalents (Foster, 1979; De Jet-

610

S, MCI_OlJGH1

DEPOSITIONAL LITHOLOGY ENVIRONMENT 28 z

FOSSILS SEDIMENTARY STRUCTURES

KEY

mm

Lacustrine

Coal

26 Shale

Forest swamp

1 Siltstone

24

Sandstone 22 Levee, overbank, and crevasse sediments

Flat lamination Cross-lamination

20

\\"" .

18

7% 16

\\\

Cross-bedding; LA low angle;

Ttrough

~

Soft sediment deformation

O

Intraformationat clasts

~ Gl ossopteris leaves

LA

14 Fern foliage Channel and point bar sediments 12

~

Schi zoneura foliage Phyl lotheca stems and

10

foliage 8

\ \ \

T

Indeterminate fragmentary foliage Fragmentary coalified wood/ fusain

6 Lacustrine ~ ) 4

Silicified/ coalified wood

Vertebraria

(roots)

21 Forest swamp 0

--I-TW-W'W7 clay silt sand Fig. 6. Graphic sedimentological log of the Late Permian Pollux-Castor interseam sediments, Rangal Coal Measures (alluvial plain Io upper deltaic setting), South Blackwater Mine, Bowen Basin, Queensland, showing concentration of sphenophyte, pteridophyte, and glossopterid leaf remains in paludal and lacustrine facies, and abundant large axes in channel deposits

PLANT FOSSIL DISTRIBUTIONSIN SOME A U S T R A L I A N PERMIAN NON-MARINE SEDIMENTS

sey, 1979; McLoughlin, 1990) suggesting a minor marine or brackish-water influence. As in the Collie Coal Measures, the South Blackwater coal seams (Fig. 6) contain few identifiable macroscopic plant remains although large compressed woody axes are evident along bedding planes and Vertebraria roots extend in some abundance into underlying beds. The coal seams split and coalesce over distances of tens of kilometres (Staines, 1972; Svenson and Peterson, 1983). Typically the coals are transitionally overlain by a flat and small-scale cross-laminated carbonaceous shale, siltstone, and fine-grained sandstone facies yielding abundant well-preserved glossopterid, fern, and sphenophyte foliage, axis, and fruit remains (Fig. 6). This facies is interpreted to represent low-energy lacustrine conditions developed after drowning of the peat-producing community. Reed-like sphenophytes such as Phyllotheca (Fig. 1J) are most abundantly preserved, often to the exclusion of all other plant remains, in finely laminated lacustrine shales such as those within the Rangal Coal Measures and the underlying Burngrove Formation and Black

611

Alley Shale (Fig. 6; McLoughlin, 1992a). Similar dense mats of commonly aligned Phyllotheca buried by flood deposits were recognized by Johnson (1984) in claystone marsh facies of the Moranbah Coal Measures, northern Bowen Basin. Archangelsky (1981) and Draper and Beeston (1985) also found sphenophyte remains to be most abundant in Permian mire and lacustrine facies, but scarce in alluvial fan deposits. Hence Phyllotheca and some morphologically similar Lelstotheca species probably occupied ecological niches similar to modern Northern Hemisphere horsetails (Equisetum) colonizing marsh, lake margin, and exposed and disturbed channel bar environments (Raven et al., 1986; Williams and Rust, 1969; Rayner, 1992). Osmundaceous or marrattiaceous ferns assigned to Neomariopteris and Dichotomopteris are widely represented in Australian Permian paludal and lacustrine facies of delta plain settings (Table 1, Figs. 6, 8). Silicified short tree-fern trunks presumably bearing Neomariopteris or Dichotomopteris foliage (Fig. 1K) are common in permineralized peat deposits in Late Permian units of

Fig. 7. Silicified gymnosperm logs preserved in fluvial sandstones of the Late Permian Fair Hill Formation, Scrub Creek, north of Blackwater, Bowen Basin. H a m m e r is 26 cm.

612

'q. M('IAIUGH| 1N

the Bowen Basin (Gould, 1970). Few other macroscopic fern taxa are known from Australian P e r m i a n formations despite an a b u n d a n c e and DEPOSITIONAL ENVIRONMENT

LITHOLOGY

FOSSILS & FORMATION SEDIMENTARY STRUCTURES

69

Interdistributary ba'y Cr - - ~ , , , Interdistributary bay

P ~

Cr

Floodplain Cr -'Lacustrine 60 Mire "Distributary channel & levee Mire Cr --~ "lSdal inlet Minor channel

diversity of pteridophytic p a l y n o m o r p h s in these sediments (Balme and Hennelly, 1956; Foster, 1979; Gilby and Foster, 1988). Many ferns proba-

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CARYNGINIA FORMATION

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KEY

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IRWIN

Lacustrine & floodplain

)-/->._

Erosion surface Cross-bedding (P-Planar, T-Trough, LA-Low angle'

RIVER COAL MEASURES

Vertical burrows Horizontal & oblique burrows

Glossopteris spp. Gangamopteris spp.

>~..~ Mire

-- ] L 7-/'7- p "~-,-. Cr -B- . . . . . . t ~ Levee& :.:.:_::]i!!::::::::'~i! ~ Z I ' [ ~ floodplain with 30 " ' ~ ~ tl| Distributary channel --

~ . : ._:. " ":." ;:.:' : '~~ ' ; ' " ' " "

777 T

Sphenophyllum rhodesii Sphenophyllum morganae Lelstotheca & Phyllotheca spp. Gondwanophyton daymondii ",~ Fern foliage I~

Mire Levee & overbank-Mire ---Channel & levee Floodplain, interdistributary bay

Sphenophyte rhizomes

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~7-,-..7 F

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7 F Vertebraria Fragmentary plant remains Cr= Crevasse splay

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Compressed woody axes

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Shale

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777- T

Siltstone Sandstone

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Conglomerate HIGH ~LiFF 0. ~ ~ SANDSTONE Clay Silt Sand Gran. Peb. Fig. 8. Graphic sedimentological log of a lower delta plain sequence exposed in the type section of the Early Permian Irwin River Coal Measures, North Irwin River, northern Perth Basin, showing abundant representation of herbaceous pteridophytes and sphenophytes. Shoreface

P L A N T FOSSIL D I S T R I B U T I O N S IN SOME A U S T R A L I A N P E R M I A N N O N - M A R I N E S E D I M E N T S

bly occupied non-depositional sites or epiphytic niches not conducive to preservation of their delicate vegetative parts. Following the lacustrine succession overlying the Pollux Seam (Fig. 6), channel avulsion resuited in deposition of a thick series of crossstratified channel sandstones. This sandstone facies commonly shows a basal lag of shale intraclasts, a fining-upwards grain-size profile, and lateral accretion surfaces on the scale of tens to hundreds of metres in lateral extent. Few identifiable leaf remains are evident within this facies but silicified logs up to 1 m in diameter and 30 m long (mostly < 10 m long: Fig. 7) are common. Woody gymnosperm axes are able to withstand extended aquatic transportation. Logs in lowsinuosity fluvial deposits tend to be distributed in bimodal orientations. Preservation transverse to the palaeocurrent direction results from debris accumulation against channel bars or obstacles, whereas rotation of the free ends of partially stranded axes may align them with the prevailing current. Stranded logs may locally influence channel and bar distribution and can survive for long periods ( > 200 years) in fluvial environments before burial or decay (Keller and Tally, 1979; Gastaldo, 1989). Sideritized and coalified in-situ gymnosperm stumps initially growing in paludal situations are locally overlain by coarse crevassesplay sandstones in some Bowen Basin coal measures (Johnson, 1984) signifying that the Permian mires supported arborescent vegetation. The distribution of silicified wood is strongly influenced by sediment chemistry and porosity. Hence, porous volcanigenic sediments with abundant free silica are often rich in silicified plant remains (Jefferson, 1987). Silicified wood is also common in nearshore Permian marine units of eastern Australia having a high volcanigenic sediment content (e.g., the Peawaddy and MacMillan Formations, Bowen Basin) although logs in these formations are typically fragmentary and irregularly oriented (McLoughlin, 1990). The interbedded siltstone, cross-laminated sandstone, and minor coal-bearing interval overlying the sandstone facies (Fig. 6) contains mostly degraded foliage and stem remains together with minor roots (Vertebraria), particularly in the up-

613

per part where this succession is overlain by the Castor seam. This interbedded facies is interpreted to represent deposition in a mixture of overbank marsh, levee, crevasse splay, and minor channel settings. Although levee environments often accumulate thick layers of plant litter, bioturbation, fluctuations in the water table and the actions of decomposer organisms generally result in a poor preservational potential for plants in modern subsurface levee sediments (Scheihing and Pfefferkorn, 1984; Gastaldo, 1989). This also appears to have been applicable to Permian levee and non peat-forming floodplain deposits. Australian Permian lower alluvial plain to upper delta plain plant assemblages are thus dominated by glossopterid remains with only minor contributions from other gymnosperms but significant input from pteridophytes and reed-like sphenophytes (Table 1).

Irwin River Coal Measures (lower delta plain environments) The Artinskian Irwin River Coal Measures are restricted to the northern Perth Basin, Western Australia, where they conformably overlie the high-energy, nearshore marine, High Cliff Sandstone and are conformably overlain by the lowenergy, restricted marine, Carynginia Formation. The Irwin River Coal Measures represent a deltaic wedge which prograded into a marine embayment developed in the northern Perth Basin after the retreat of glacial conditions. The formation's type section (Fig. 8) exposes a diverse array of sediments variously grouped into channel, floodplain, mire, lacustrine, and estuarine facies indicative of a delta plain setting. Trough cross-bedded arkosic sandstone sets of 1-3 m amplitude, typically with polymict conglomeratic lag horizons and scattered shale intraclasts, constitute the channel facies. Fossils are rare in the sandstones apart from indeterminate carbonaceous matter reworked from underlying sediments. Floodplain facies lacking peat are represented by interbedded carbonaceous siltstones, shales and cross-laminated fine-grained sandstone. Thin (< 30 cm) granule and pebble conglomeratic

614 crevasse-splay deposits are also represented within this facies. The fine-grained lithologies commonly host fragmentary, or occasionally well-preserved, glossopterid, fern, and sphenophyte foliage and axis remains. Gtossopterid and articulated sphenophyte roots and rhizomes occur abundantly in palaeosols developed within this facies. Slender-stemmed, broad-leafed, sphenophytes (e.g., Raniganjia, Sphenophyllum, Trizygia and Schizoneura) were probably herbaceous plants commonly occupying samphire-like niches in exposed lower deltaic settings (margins of interdistributary bays) where lack of a permanent freshwater table generally allows only salinity tolerant non-arborescent vegetation to survive (Frazier and Osanik, 1969; Gastaldo, 1989). Such Australian Permian sphenophytes are best represented in lower deltaic siltstones of the Irwin River Coal Measures (Fig. 8; McLoughlin, 1992b). The matted rhizomes, bulky foliage, and slender axes of some species (Fig. 1A) suggest that these plants grew in dense thickets where mutual support allowed maintenance of an upright growth habit. Alternatively, some forms with development of climber hooks or pronounced bilateral symmetry (viz., SphenophyUum morganae Rigby, Fig. 1B; Raniganfia minima Rigby, Fig. 1D; Schizoneura gondwanensis Feistmantel, Fig. 1C) may have been adapted to a climbing or scrambling habit in the understory of alluvial and upper delta plain glossopterid woodlands. Coal seams, as in the previously discussed case studies, generally lack identifiable macroscopic plant remains apart from fragmentary woody material. The Irwin River coals are high in ash and moderately high in sulphur (Kristensen and Wilson, 1986), reflecting a probable rheotrophic mire origin. The coals show repeated seam splits reflecting frequent channel migration across peatforming environments. The lacustrine facies, as in the previous case studies, consists of finely laminated shales and siltstones commonly hosting densely matted glossopterid leaf, fruit, and axis remains. Cycadophytes have been recorded from lower deltaic sediments of the Irwin River Coal Measures (Rigby, 1966). However, they are more typical of alluvial plain and well-drained upper deltaic de-

s. MCLOUGHI.IN posits (e.g., Wagina Sandstone, Perth Basin; Rangal Coal Measures, Bowen Basin; Dunedoo Formation, Sydney Basin: (Rigby, 1966; Holmes. 1977; McLoughlin, 1992a). Fresh- and brackish-water algae are common within the coals and lacustrine facies of the Irwin River Coal Measures as they are within other Australian coal measures (Segroves, 1967, 1972: Backhouse, 1991; Guy-Ohlson, 1992). They occasionally form thick, finely laminated, oil shale deposits in lacustrine facies (e.g., in the Bandanna Formation, southwestern Bowen Basin). However, these fresh- or brackish-water algal colonies and cysts, notably belonging to the genera Botryococcus, Brazitea, Chordecystia, Cir-

culisporites, Maculatasporites, Mehlisphaeridium, Peltacystia, Pitasporites, Portalites, Quadrisporites, Spongocystia and Tetraporina, are also well-represented in lagoonal and interdistributary bay deposits where they are often mixed with spinose acritarchs typical of more open marine conditions (Segroves, 1967; Foster, 1979; Fielding and McLoughlin, 1992). The estuarine facies comprises packages ot thin ( < 30 cm) bimodally cross-bedded or undulatory and cross-laminated sandstones together with flasers of carbonaceous siltstones. Though identifiable plant remains are rare, abundant fine carbonaceous material and irregularly oriented invertebrate burrows within this facies attest to a lower delta plain depositional setting, lnterdistributary bay facies interfingering with and overlying this sequence consist of finely laminated to highly bioturbated black shales and siltstones interbedded with thin discontinuous lenses of cross-laminated and commonly hummocky crossstratified fine-grained sandstone. In summary, Australian Permian lower delta plain plant assemblages are dominated by herbaceous sphenophytes, pteridophytes and lycophytes, with additional significant contributions from glossopterids and mixed freshwater-marine algae and acritarchs in certain facies (Table 1). Summary of Permian plant communities Early Permian Gangamopteris-rich floras have been likened to modern high-latitude birch (Be-

P L A N T FOSSIL D I S T R I B U T I O N S IN S O M E A U S T R A L I A N P E R M I A N N O N - M A R I N E S E D I M E N T S

tula) taiga of the Northern Hemisphere (Retallack, 1980). Glossopteris-dominated woodlands replaced the Gangamopteris flora with amelioration of the climate during the late Early Permian (though cool temperate and strongly seasonal conditions still prevailed). Australian glossopterids display reduced leaf sizes towards the end of the Permian (Retallack, 1980), probably in response to warmer climates and increased water stress. In the Late Permian, large (mesophyll-sized) and broad-meshed Glossopteris leaves remain in abundance in Bowen Basin paludal facies, whereas smaller (nanophyllto notophyll-sized; Webb, 1959) narrow-meshed leaves typify lacustrine and exposed floodplain deposits (McLoughlin, 1993a, b). Broad-meshed leaves (Fig. 1I) lack thick hypodermal layers (Pigg, 1990) and may have been adapted to shaded forest-swamp settings where evapotranspiration stress was low. In drier, sparsely vegetated, floodplain environments physical attrition and greater evapotranspiration rates may have induced the closely spaced venation, prominent hypodermis development, and smaller sizes of the majority of leaves (McLoughlin, 1990). Permian silicified peat in the Bowen Basin is dominantly composed of stacked glossopterid leaves and fruits, and irregularly oriented glossopterid roots (Fig. 5). Subsidiary elements include fern and sphenophyte foliage, axes, and sporangia together with various indeterminate gymnosperm axes and seeds (Gould, 1970; Beeston, 1986; McLoughlin, 1990). The strong seasonality of the high-latitude Permian (Gondwanan) climates contributed to seasonal variations in palynofloral assemblages (Rocha-Campos and Sundaram, 1981) and presumably also affected local macrofossil representation. Other taphonomic factors comparable to those acting on plant debris accumulations in modern alluvial plains and deltas (Scheihing and Pfefferkorn, 1984; Gastaldo, 1989; Gastaldo et al., 1989; Rich, 1989; Burnham et al., 1992) would ~lso have influenced the composition of the Permian plant assemblages. However, Burnham et al. (1992) noted that although rare forest species are poorly represented in litter samples, the relative abundances of dominant and sub-dominant

615

species do generally correspond to their representation in leaf litter assemblages. Plant groups preserved as impressions and compressions in Australian Permian interseam assemblages do appear to reflect, in general terms, the composition of the coal-producing flora on the basis of comparisons with organs preserved in silicified peat. Subtle variations are, however, apparent in the plant-organ and taxonomic representation within individual facies owing to differences in the prevailing energy regime, physical and chemical durability of particular plant groups and organs, and degree of transport, together with biases of taxonomic approach by individual workers. The chief floral differences within Australian Permian sequences are between assemblages derived from different environmental tracts (viz., alluvial plain versus deltaic settings). Australian Permian lowland mires appear to have been universally dominated by glossopterids on the basis of preserved remains in silicified peats, leaf litter in associated sediments, glossopterid roots underlying coal seams, and sporadic coalifled stumps projecting above seams. Osmundaceous ferns and some sphenophytes and lycophytes appear to have been elements of the glossopterid forest understory although they are especially well-represented in more open lakemargin and floodplain deposits on the fringes of the glossopterid communities. In lower deltaic settings scrambling herbaceous plant communities rich in sphenophytes and ferns (evidenced by both foliage-rich beds and matted rhizome deposits) appear to have dominated the vegetation. Non-depositional drier sites probably supported a greater proportion of non-glossopterid gymnosperms (conifers, cordaitanthaleans, ginkgophytes, cycadophytes, and pteridosperms) owing to the greater frequency of their remains in alluvial plain sediments close to basin margins. Elements within these more hydrophobic communities were probably favoured by drying of the climates towards the close of the Permian and taxa within these groups subsequently colonized the Triassic lowlands following the disappearance of the glossopterids (Retallack, 1980). The glossopterid dominance of the lowland floras appears to have ended with their rather

616 sudden demise at, or shortly before, the close of the Permian. The Late Permian glossopterid-rich coals of eastern Australia are overlain by red-beds (Day et al., 1983). Retallack (1980) noted that glossopterid remains are replaced in these sediments by the pteridosperm Dicroidium callipteroides Carpentier (in fluvio-lacustrine facies) and the conifers Brachyphyllum and Voltziopsis (in better-drained floodplain environments). Regional uplift (Retallack, 1980) and drier climates (Gould and Shibaoka, 1980) probably contributed to the disappearance of favourable habitats for glossopterids. There are few indications of direct interaction between animals and plants in the Gondwanan Permian. Scarce reports of insect damage on glossopterid leaves (Plumstead, 1969; van Dijk, 1981; Srivastava, 1987; McLoughlin, 1993a) represent the only direct evidence for herbivory although Rayner (1992) speculated that the axial stems and subterranean rhizomes of Phyllotheca (Sphenophyta) were the principal food source of some dicynodonts based on the animals' dentition and the distribution patterns, environmental preferences, and stature of both the plants and animals. Fungal degradation is a common feature of Permian Gondwanan woods (White, 1969; Schopf, 1970; Mussa, 1980; Stubblefield and Taylor, 1986; Pant and Singh, 1987; McLoughlin, 1992a) and fungae-derived macerals are frequently found in Gondwanan coals (Chandra and Taylor, 1975). The actions of fungi and other decomposers may have represented an important process in the degradation of plants buried in levee and floodplain sediments (as they do in equivalent modern settings; Gastaldo, 1989). Despite postulated major falls in global atmospheric 0 2 during the Permian (Cope and Chaloner, 1980; Robinson, 1989) and the consequent likely decrease in forest fire frequency, no consistent decrease of inertinite macerals in Australian coals is evident through this interval (Smyth, 1984). Little detailed work has been undertaken on the regional distribution of pyrofusinite in Australian Permian coals. Nevertheless fusinite content is locally quite high (Sappal, 1986).

s. MCI.OUGHI.IN Discussion and conclusions

Australian Permian alluvial and delta plain deposits contain distinctive suites of plant fossils (Table 1). Coal mire floras can clearly differ from assemblages contained in interseam sediments (Phillips and Peppers, 1984; Draper and Beeston, 1985). However, Australian Permian macrofloras are of relatively low diversity and impression/ compression floras adjacent to coal seams appear to be representative of the coal-forming flora on the basis of comparable plant remains in silicified peats. Though clearly some constituents are allochthonous (Draper and Beeston, 1985), Australian Permian coals are nevertheless rich in in-situ plant remains. The low diversity of plants incorporated in the coal measures is partly related to their cool temperate climatic setting during deposition and partly a function of floral impoverishment in mire communities generally (Phillips and Peppers, 1984; Gastaldo, 1987). Raised peats show especially low floristic diversity (McCabe, 1984) and some Australian coals, particularly in small fault-bound basins (e.g. Blair Athol, Wolfang, and Collie Basins), show other features reminiscent of such deposits (Smyth, 1980; Hobday, 1987). However, these very thick coal seams with low ash and vitrinite but high inertinite content require further sedimentological, coal petrological, and palaeobotanical studies to more clearly resolve their depositional setting. Studies of the Permian coal-forming vegetation of Australia are still in their infancy, but future research will hopefully resolve the floral composition of the coals, vegetational variations within coal mire environments, and characterize plant communities of broad-scale continental depositional systems. Acknowledsements

This study was completed while the author was the holder of an Australian Research Council Postdoctoral Fellowship at the Department of Geology, University of Western Austra}ia. The management of The Griffin Coal Mining Comparty's Muja Mine, the CSR company's South

PLANT FOSSILDISTRIBUTIONS IN SOME AUSTRALIANPERMIAN NON-MARINESEDIMENTS

Blackwater Mine, Utah company's Blackwater Mine, and Western Collieries Ltd. are thanked for permitting collection of material from their respective opencut coal mine exposures. References Archangelsky, S., 1981. Estudios fitopaleoecol6gicos en el Paleozoico Superior del Oeste de Chubut, Argentina. An. 2nd Congr. Latinoam. Paleontol., Porto Alegre, 1: 141-156. Archangelsky, S. and Cfineo, R., 1987. Ferugliocladaceae, a new conifer family from the Permian of Gondwana. Rev. Palaeobot. Palynol., 51: 3-30. Azcuy, C.L., Longobucco, M.I., Alvarez, L. and Strelkov, E., 1987. Licofitas arborescentes de la Formaci6n Cerro Agua Negra (Provincia de San Juan). Ameghiniana, 24: 257-261. Backhouse, J., 1991. Permian palynostratigraphy of the Collie Basin, Western Australia. Rev. Palaeobot. Palynol., 67: 237-314. Balme, B.E. and Hennelly, J.P.F., 1956. Trilete sporomorphs from Australian Permian sediments. Aust. J. Bot., 4: 54-67. Beeston, J.W., 1983. The application of coal petrology to source rock studies in the Denison Trough, Queensland. In: C.B. Foster (Editor), The Permian Geology of Queensland. Geological Society of Australia, Queensland Division. Brisbane, pp. 53-56. Beeston, J.W., 1986. Leptocalamites, a new genus of calamitalean wood, from Queensland. Geol. Surv. Queensl. PUN., 387: 51-56. Beeston, J.W., 1990. Cyclodendron leslii (Seward) Kr~iusel 1928 and associated palynomorphs in the Early Permian Reids Dome beds, Queensland, Australia. Alcheringa, 14: 325 -330. Burnham, RJ., Wing, S.L. and Parker, G.G., 1992. The reflection of deciduous forest communities in leaf litter: implications for autochthonous litter assemblages from the fossil record. Paleobiology, 18 (1): 30-49. Cazzulo-Klepzig, M., Guerra-Sommer, M. and Bossi, G.E., 1980. Revis~o fitoestratigrfifica do Grupo Itarar6 no Rio Grand do Sul, 1. Acampamento Velho, Cambal Grande, Bud6 e Morro Papal6o. Bol. I.G. Univ. S~o Paulo, 11: 55-76. Chandra, D. and Taylor, G.H., 1975. Gondwana Coals. In: E. Stach, M.-Th. Mackowsky, M. Teichmiiller, G.H. Taylor, D. Chandra and R. TeichmiJller (Editors), Stach's Textbook of Coal Petrology. Borntraeger, Berlin, pp. 139-159. Cooper, B.J., 1983. Late Carboniferous and Early Permian stratigraphy and microfloras in eastern Australia--some implications from a study of the Arckaringa Basin. In: C.B. Foster (Editor), The Permian Geology of Queensland. Geological Society of Australia, Queensland Division, Brisbane, pp. 215-220. Cope, M.J. and Chaloner, W.G., 1980. Fossil charcoal as

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