OFR 151.pdf - CRC LEME

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Inferred climate Some differences between the Early and mid Late Paleocene vegetation may reflect (possibly eustatic-forced) changes in depositional environment (nearshore to marginal marine). Nevertheless the paucity of rainforest species and cryptogams such as Gleicheniaceae and Sphagnum relative to Casuarinaceae and Proteaceae is consistent with rainfall being either sub-humid or humid with a pronounced dry season (possibly monsoonal). The presence of Nypa indicates conditions were very warm to hot (upper mesotherm to possibly megatherm) in the Carnarvon basin and may reflect general global warming since it predates the Paleocene-Eocene thermal maximum. The presence of Nothofagus in these conditions is anomalous. Whether similar or cooler conditions prevailed in the Perth Basin is unknown. 1.2.5 Central southern Australia 1. Duntroon Basin Early Paleocene (Lower Lygistepollenites balmei Zone Equivalent) microfloras are preserved in nearshore facies intersected by the Borda-1 and Greenly-1 wells (Morgan and Hooker 1993c, 1993d). Taxa that are common in both wells include Cyatheaceae (Cyathidites), Gleicheniaceae, Araucariaceae (Dilwynites), Podocarpaceae (Dacrydium, Lagarostrobos, Podocarpus-Prumnopitys) and Callitrichaceae. Ericales and Proteaceae are frequent, and Gambierina is present in low numbers, in Borda-1 whilst Sphagnum and a Myrtaceae (referred to Eucalyptus) are frequent to common in Greenly-1. Two species of Nothofagus (Nothofagidites brachyspinulosus, N. deminutus) are recorded in the same well. Inferred climate The presence of extensive freshwater swamps, tree- and ground-fern communities, and podocarp-dominated rainforest demonstrate conditions within the Bight were much wetter (humid-perhumid) than the present arid climate. Rainfall may have been seasonal but any dry period was shorter or less severe than in northwestern Australia. Temperatures during the Early Paleocene were relatively warm (lower mesotherm) but it is uncertain whether the increased abundance of Araucariaceae relative to aquatic herbs such as Callitrichaceae and mesophytic cryptogams during the Late Paleocene reflects global warming or is due to an enhanced Neves Effect. Circumstantial evidence for local warming is provided by the earlier prominence of Myrtaceae and Euphorbiaceae (Austrobuxus-type) in the Bight than in the Otway and Gippsland Basins to the east. 1.2.6 South-East Australia 1. Southeastern Highlands Late Paleocene (~58-60 Ma) microfloras preserved in Lake Bungarby (Taylor et al. 1990) are co-dominated by Gleicheniaceae, Araucariaceae (Agathis/Wollemia), Podocarpaceae (chiefly Podocarpus-Prumnopitys and extinct spp. of Dacrydium and Lagarostrobos), ancestral Nothofagus (Nothofagidites endurus), Nothofagus (Fuscospora) spp., several Proteaceae (Basopollis, Proteacidites) and the probable Caryophyllaceae (Periporopollenites polyoratus). The diversity is low but the rare angiosperm component includes a number of types that are more typical of sites at low elevations, for example Anacolosa (Anacolosidites acutullus), Casuarinaceae, Euphorbiaceae (Austrobuxus-type), Gambierina, Ilex, Winteraceae and Xylomelum occidentale-type. Sphagnum is uncommon. Carbonaceous shales of possibly similar (possible Late Paleocene) age from Bowral are dominated by Osmundaceae, 207
Araucariaceae (Araucaria) and Podocarpaceae (Dacrydium) with minor Gambierina, Callitrichaceae and Casuarinaceae (McMinn 1989a). This gymnosperm-dominated community appears to have been similar to coastal communities in the Gippsland Basin and implies that Austral Conifer Forest formed the regional forest vegetation across southeastern Australia during the Paleocene. Conditions appear to have been relatively cool (lower mesotherm) and wet to very wet (humid-perhumid) but not to the extent of allowing extensive Sphagnum raised bogs to develop across the uplands. Inferred climate The expansion of Araucariaceae and a diverse group of rainforest angiosperms during the Late Paleocene is consistent with significant warming although mean temperatures are likely to have remained within the lower mesotherm range. Rainfall appears to have remained high (perhumid) with no pronounced seasonal bias. 2. South Coast of New South Wales Sediments of probable Late Paleocene age have been dredged from the continental shelf off Jervis Bay (Ocean Science Institute FR 5/91-30 DB13) on the South Coast of New South Wales (M.K. Macphail and A.D. Partridge, unpubl. results). The spore-pollen component is dominated by Casuarinaceae and podocarps, in particular Dacrydium (Lygistepollenites balmei), Microcachrys, Podocarpus-Prumnopitys and Podosporites. Blechnaceae and Lagarostrobos are frequent. Rare taxa include Gleicheniaceae, Dacrydium (Lygistepollenites florinii), Halocarpus, Phyllocladus, Callitrichaceae, probable Caryophyllaceae (Periporopollenites polyoratus), Gambierina, ancestral Nothofagus, Proteaceae and several angiosperm types with no known NLRs. Taxa with modern mesotherm affinities are absent, including Araucariaceae. Pollen dominance almost certainly has been skewed by the Neves Effect. Nevertheless the results demonstrate that a form of Austral Conifer Forest extend northwards along the eastern margin to about palaeolatitude 57 0 S during the Paleocene. Dacrydium (Lygistepollenites balmei, L. florinii) and Casuarinaceae appear to have lined coastal rivers or formed extensive swamp communities on the coastal plains. Inferred climate Climates are interpreted to have been relatively wet (humid) and within the lower mesotherm range. Low photoperiod is unlikely to have been ecologically significant at this latitude but conditions may have been influenced by cool currents flowing northward along the eastern margin. 3. Gambier Basin Rowett (1997a) has recorded a possible Lygistepollenites balmei Zone Equivalent microflora in McNicol-1 but few details are available. 4. Otway Basin Late Paleocene microfloras from Copa-1, offshore western Otway Basin (Macphail and Hos 1990) are dominated by Araucariaceae (Araucariacites, Dilwynites) with frequent Austrobuxus-type and Casuarinaceae. Gambierina is present in low numbers. Otherwise the only detailed data on Paleocene floras come from outcrops of the Pebble Point and Dilwyn Clay Formations (Wangerrip Group) near Princetown on the Otway coast (see Table 1 in Harris 1965a, Partridge 1999). Foraminifera and dinoflagellates provide independent age control. 208
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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
Page 158 and 159: Raymo, M.E., Grant, B., Horowitz, M
Page 160 and 161: Sereno, P.C., 1999. The evolution o
Page 162 and 163: Taylor, G., 1998. Prediction of mod
Page 164 and 165: Webb, L.G., 1968. Environmental rel
Page 166 and 167: Zachos, J.C., Stott, L.D. and Lohma
Page 168 and 169: APPENDIX 1 CRETACEOUS DATA 167
Page 170 and 171: 1. TIME SLICE K-1 Age Range: Berria
Page 172 and 173: Australian assemblages, located on
Page 174 and 175: 2. Officer Basin Dinoflagellates in
Page 176 and 177: 2. TIME SLICE K-2 Age Range: Aptian
Page 178 and 179: Inferred climate The combined data
Page 180 and 181: Dettmann et al. (1992) have argued
Page 182 and 183: 3. TIME SLICE K-3 Age Range: Cenoma
Page 184 and 185: 3.2.2 North-East Australia 1. Carpe
Page 186 and 187: 4. TIME SLICE K-4 Age Range: Turoni
Page 188 and 189: 1. Otway Basin Limited data (Macpha
Page 190 and 191: 5. TIME SLICE K-5 Age Range: Early
Page 192 and 193: Inferred climate The data indicate
Page 194 and 195: 6. TIME SLICE K-6 Age Range: Late C
Page 196 and 197: Contrary to global cooling trends d
Page 198 and 199: Inferred climate The relatively goo
Page 200 and 201: Inferred climate As for regions to
Page 202 and 203: 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 210 and 211: Microfloras preserved in the Lower
Page 212 and 213: subtropical affinities are rare, hi
Page 214 and 215: 2. TIME SLICE T-2 Age Range: Early
Page 216 and 217: Inferred climate Climates appear to
Page 218 and 219: northern New South Wales. The assem
Page 220 and 221: 2.2.5 Central southern Australia Ha
Page 222 and 223: a number of distinctive Proteaceae
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 254 and 255: (Morgan 1977, McMinn 1981a, Martin
Page 256 and 257: common (up to 5-6%) in the middle s
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Polypodiaceae, Palmae (Dicolpopolli
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Strasburgeriaceae. Proprietary info
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Rare taxa which first appear in the
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Correlative microfloras in the onsh
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impression of floristic impoverishm
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(Lophosoria) reached Tasmania befor
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2. Otway Basin Oxygen isotope strat
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5. TIME SLICE T-5 Age Range: Late M
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Casuarinaceae, Cunoniaceae, Elaeoca
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maximum temperature of the hottest
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Nothofagus-gymnosperm temperate rai
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5.2.7 Tasmania Late Neogene sedimen
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