OFR 151.pdf - CRC LEME

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(Morgan 1977, McMinn 1981a, Martin 1988, 1991b, 1997b, Macphail 1996c, 1997a). The age determinations are based on floristically impoverished Nothofagidites assemblages that lack index species found in younger (Late Miocene-Pliocene) or older (Eocene) microfloras. None of the zone index species used to subdivide Oligocene-Middle Miocene time in southern Australia have been recorded to date in central Australia and the age determinations remain provisional. 1. Callabonna Sub-basin The one known assemblage from the Namba Formation is moderately diverse, with dominance shared between Cyathea (10%), gymnosperms (total 21%) and Restionaceae (39%). Frequent to common types are Podocarpus-Prumnopitys (9%), Dacrydium (5%), Lagarostrobos (3%), Phyllocladus (3%), Nothofagus (Brassospora) spp. (4%), Sparganiaceae (5%) and Cyperaceae (2%). Rare taxa include Araucariaceae (Agathis/Wollemia), Anacardiaceae, Caesalpinaceae and Eucalyptus. Proteaceae are absent. 2. Alice Springs District Pollen dominance is shared between Gleicheniaceae, Podocarpaceae (Podocarpus- Prumnopitys), Casuarinaceae and Nothofagidites (Brassospora) spp. For example the Borehole RN 16861 is wholly dominated by Nothofagus (Brassospora) spp. (59%) with lesser amounts of Casuarinaceae (27%), Podocarpus-Prumnopitys (7%) and Dacrydium (4%). Low numbers of Botryococcus cysts imply the depositional environment was an ephemeral, brackishwater lake. Correlative Nothofagus (Brassospora) microfloras from the Burt Plain Basin occasionally include frequent to common numbers of Blechnaceae, Araucariaceae (Araucaria), Malvaceae (Malvacearumpollis) and unidentified tricolporate types. Rare taxa include Pteris, Araucariaceae (Agathis/Wollemia-type), early records of Sprengelia-type (Epacridaceae) and Grevillea-Hakea (Proteaceae), Menyanthaceae (cf. Villarsia), Onagraceae (cf. Epilobium) and an unidentified Sparganiaceae. Cyperaceae, Myrtaceae (including Eucalyptus) and Restionaceae are very rare or absent. Assuming that the Namba and Alice Springs sequences are broadly contemporary, relative abundances appear to have been shaped by the depositional environment and regional topography. For example, the prominence of Nothofagus (Brassospora) spp. in the Alice Springs district compared to the Lake Eyre Basin almost certainly is due to the proximity of uplands such as the McDonnell Ranges. Conversely sedges and other swamp taxa are better represented in the low-lying Lake Eyre Basin. Apart from Casuarinaceae, which may include the dry sclerophyll genera Allocasuarina/Casuarina as well as Gymnostoma, it is unclear which taxa occupied dry interfluve sites. Halophyte taxa such as Chenopodiaceae- Amaranthaceae (Chenopodipollis chenopodiaceoides) or Wilsonia (Tricolpites trioblatus) appear to be absent although both occur in saline-influenced deposits in the Murray Basin by this time. Inferred climate The floristically and ecologically heterogeneous composition of the microfloras in central Australia point to relatively cool (lower mesotherm) and seasonally wet (humid) conditions in which mean summer rainfall was inadequate to support rainforest trees away from stream banks or sheltered gullies. The ephemeral nature of depositional environments also point to dry summers during which rivers fragmented into brackishwater swamps. 253
4.2.4 South-West Australia 1. Yilgarn Craton A depauperate Oligo-Miocene (Proteacidites tuberculatus Zone Equivalent) microflora is preserved at ca. 50 m depth in Rollo's Bore near Norseman in south-west Western Australia (M.K. Macphail unpubl. results). Some reworking is evident in that the assemblage also includes the Early Jurassic species Exesipollnites tumulus. Otherwise the assemblage is wholly dominated by Nothofagus (Brassospora) spp. (74%) and Casuarinaceae (15%). Uncommon (< 3%) to rare taxa include lycopods (Foveotriletes balteus, Latrobosporites marginis), Gleicheniaceae (cf. Sticherus), Cyathea and related trilete spores (Cyathidites minor), Araucariaceae (cf. Agathis), Dacrydium, Lagarostrobos, Podocarpus-Prumnopitys, Microcachrys (Microcachrydites antarcticus, Podosporites microsaccatus), Ericales, Sparganiaceae (Aglaoreidia qualumis), Strasburgeriaceae, Trimeniaceae (Periporopollenites demarcatus), two Beauprea spp. (Beaupreaidites elegansiformis, B. verrucosus) and a distinctive but as yet unidentified tetracolporoidate species. The closest recorded analogues are Oligo-Miocene microfloras preserved in the Alice Springs District (Macphail 1997a). Frequent Nothofagidites falcatus demonstrates the microflora is no older than Middle Eocene. The minimum age is more difficult to determine since all species are long-ranging or (B. verrucosus) possibly have extended time distributions in south-west Western Australia. However, geological data (P. de Broekert, pers. comm.) indicate the unit is younger than palaeochannel deposits that preserve diverse Late Eocene, Middle N. asperus Zone Equivalent microfloras. Inferred climate The microflora appears to represent floristically impoverished Nothofagus rainforest or scrub growing around a freshwater reed swamp. Such a community is ecologically consistent with relatively cool (lower mesotherm) but uniformly wet (humid) conditions during the Eocene- Oligocene transition although similar conditions may have persisted into Early Miocene time. 4.2.5 Central southern Australia 1. St. Vincent Basin Probable Proteacidites tuberculatus Zone Equivalent and Canthiumidites bellus Zone Equivalent microfloras occur in marine facies in the Barossa Valley (Alley 1989) and St. Vincent Basin (Rowett 1993b), respectively. In both cases, the age determination is based on the absence or presence of species that first appear in the late Early Miocene in the Gippsland Basin, e.g. Canthiumidites bellus. Pollen dominance in the older (Barossa) microfloras is shared between Blechnaceae (7-13%), Lagarostrobos (4-36%), Casuarinaceae (5-27%) and Nothofagus (11-29%) associated with occasionally frequent to common Dacrydium (4-6%), Halocarpus (up to 13%), Proteaceae (up to 13%) and a possible Meliaceae (8%). A short sequence of three microfloras provide a broad-brush record of floristic and vegetation change during the late Early-Middle Miocene in the St. Vincents Basin. The lowermost assemblage is characterised by Lagarostrobos (9%), Podocarpus-Prumnopitys (6%), Casuarinaceae (13%) and Nothofagus (13%) associated with rare occurrences of Asteraceae (Tubuliflorae) and Sparganiaceae. The higher microfloras are characterised by higher values of Cyatheaceae, Podocarpaceae (Dacrydium, Podocarpus- Prumnopitys), Casuarinaceae, Myrtaceae (5-9%) and Restionaceae (Milfordia homeopunctata). Araucariaceae (Araucaria, Agathis/Wollemia) and Phyllocladus are 254
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CRCLEME Cooperative Research Centre
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Electronic copies of the publicatio
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and, for Tertiary continental seque
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2. Analysis of a Plio-Pleistocene l
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Table A (cont.) Basin and related s
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Figure A: Generalised climatic curv
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Carpenter, R.J., Hill, R.S., Greenw
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Hill, S.M., Eggleton, R.A. and Tayl
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Macphail, M.K. and Stone, M.S., 200
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Swenson, U., Backlund, McLoughlin,
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EXECUTIVE SUMMARY This review prese
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Temperature Climates in palaeo-sout
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SUMMARY OF INFERRED CRETACEOUS PALA
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INTRODUCTION Mineral resources, whe
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Professor B. Balme (Geology Departm
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Section 7 (Tertiary climates) This
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vegetation. Moreover, individual ta
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1.3 Flora, vegetation and climate 1
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TABLE 2: Classification of vegetati
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Figure 2: Relationship of different
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Accordingly, only at sites with exc
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2.1.3 Palaeoecology Palaeoecology i
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wind-pollinated trees and shrubs bu
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1. The usual practice of equating t
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1. Palaeontological evidence Like p
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5. Facies architecture and lithostr
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Subsequent developments include mel
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SECTION 4 (GEOGRAPHIC BOUNDARIES AN
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SECTION 5 (EARLY CRETACEOUS CLIMATE
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events on other continents and sugg
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If these considerations apply to th
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surrounding basins. Thick sands ero
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Haig and Lynch 1993, Erbacher et al
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SECTION 6 (LATE CRETACEOUS CLIMATES
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has highlighted the roles played by
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6.4.2 Palaeobotany Cenomanian flora
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Palaeo-southern Australia Dryland c
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6.7 Time Slice K-6. Late Campanian-
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7.1. Global backdrop SECTION 7 (TER
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Explanations for the PETM are centr
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East Antarctica and strengthening o
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amplifying, pacing and potentially
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southeastern Australia than elsewhe
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7.4 Time Slice T-1. Paleocene [65-5
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Palaeo-southern Australia Unlike no
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Palaeo-central Australia As for the
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7.6.2 Palaeobotany The palaeobotani
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Zone microfloras imply temporary wa
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in the Bass Basin, the basal Seaspr
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Similarly it is difficult to summar
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However, the data are emphatic that
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margin of plateau were cooler (~7 0
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fossil taxa that are morphologicall
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during Late Pleistocene glacial max
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SECTION 8 (CONCLUSIONS) Climatic in
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• On present indications, Early C
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TABLE 8a: INFERRED CRETACEOUS PALAE
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8.2 Results in prospect (recommenda
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The 10 μm sieved, oxidised extract
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phenology. The method also provides
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SECTION 9 (REFERENCES) Acton, G.D.
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Ashley, P.M., Duncan, R.A. and Feeb
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Birks, H.J.B. and Gordon, A.D., 198
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Burnham, R.J., 1989. Relationships
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Clarke, J.D.A., 1994. Evolution of
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Dettmann, M.E. and Playford, G., 19
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Evans, P.R., 1970b. Palynology of H
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Godthelp, H., Archer, M., Cifelli,
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Harris, W.K., 1974. Biostratigraphy
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Hill, R.S., 1994b. Nothofagus smith
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Holland, S.M. and Patzkowsky, M.E.,
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Australia: paleoceanographic implic
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Lindsay, J.M. and Harris, W.K., 196
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Macphail, M.K., Colhoun, E.A. and F
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McGowran, B. and Beecroft, A., 1985
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Morgan, R., 1977. Palynology of Ter
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Abstracts of the Annual General Mee
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Raymo, M.E., Grant, B., Horowitz, M
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Sereno, P.C., 1999. The evolution o
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Taylor, G., 1998. Prediction of mod
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Webb, L.G., 1968. Environmental rel
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Zachos, J.C., Stott, L.D. and Lohma
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APPENDIX 1 CRETACEOUS DATA 167
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1. TIME SLICE K-1 Age Range: Berria
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Australian assemblages, located on
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2. Officer Basin Dinoflagellates in
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2. TIME SLICE K-2 Age Range: Aptian
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Inferred climate The combined data
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Dettmann et al. (1992) have argued
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3. TIME SLICE K-3 Age Range: Cenoma
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3.2.2 North-East Australia 1. Carpe
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4. TIME SLICE K-4 Age Range: Turoni
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1. Otway Basin Limited data (Macpha
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5. TIME SLICE K-5 Age Range: Early
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Inferred climate The data indicate
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6. TIME SLICE K-6 Age Range: Late C
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Contrary to global cooling trends d
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Inferred climate The relatively goo
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Inferred climate As for regions to
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APPENDIX 2 TERTIARY DATA 201
Page 204 and 205: 1. TIME SLICE T-1 Age Range: Paleoc
Page 206 and 207: also include relatively frequent No
Page 208 and 209: Inferred climate Some differences b
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Page 214 and 215: 2. TIME SLICE T-2 Age Range: Early
Page 216 and 217: Inferred climate Climates appear to
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Page 220 and 221: 2.2.5 Central southern Australia Ha
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Page 224 and 225: Inferred climate The Regatta Point
Page 226 and 227: 3. TIME SLICE T-3 Age Range: Middle
Page 228 and 229: 2. Lake Torrens Basin Abundant leaf
Page 230 and 231: Dominance is highly variable. For e
Page 232 and 233: types (M.K. Macphail unpubl. data).
Page 234 and 235: Dacrycarpus), Euphorbiaceae (Austro
Page 236 and 237: (possibly upper mesotherm) and drie
Page 238 and 239: Basin) on the Eyre Peninsula (Alley
Page 240 and 241: explanation is that a warm water gy
Page 242 and 243: several taxa, which first appear in
Page 244 and 245: 4. TIME SLICE T-4 Age Range: Oligoc
Page 246 and 247: Inferred climate The southern limit
Page 248 and 249: The lowest and possibly the oldest
Page 250 and 251: Dominants include fresh to brackish
Page 252 and 253: Based on the relative abundance of
Page 256 and 257: common (up to 5-6%) in the middle s
Page 258 and 259: Polypodiaceae, Palmae (Dicolpopolli
Page 260 and 261: Strasburgeriaceae. Proprietary info
Page 262 and 263: Rare taxa which first appear in the
Page 264 and 265: Correlative microfloras in the onsh
Page 266 and 267: impression of floristic impoverishm
Page 268 and 269: (Lophosoria) reached Tasmania befor
Page 270 and 271: 2. Otway Basin Oxygen isotope strat
Page 272 and 273: 5. TIME SLICE T-5 Age Range: Late M
Page 274 and 275: Casuarinaceae, Cunoniaceae, Elaeoca
Page 276 and 277: maximum temperature of the hottest
Page 278 and 279: Nothofagus-gymnosperm temperate rai
Page 280: 5.2.7 Tasmania Late Neogene sedimen
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