OFR 151.pdf - CRC LEME

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Correlative microfloras in the onshore Latrobe Valley are dominated by pollen and spores derived from the peat-forming vegetation. Nevertheless, immigration of dryland taxa allows the zone to be informally subdivided into three zonules – the Lower, Middle and Upper P. tuberculatus Zones – provisionally correlated with Early Oligocene (Foram Zone J-2 to J-1) time, Oligocene (Foram Zone J-2 to J-1) time, Late Oligocene (Foram Zone I-2 to H-2) time, and Early Miocene (Foram Zone H-1 and G) time (A.D. Partridge, pers. comm.). b. Early Oligocene to late Early Miocene Early Oligocene/Lower P. tuberculatus Zones assemblages have been recovered from the (offshore) Lakes Entrance Formation and (onshore) inter-seam clays below the Morwell 2A-C seam. The former are dominated by Nothofagus (Brassospora) spp. (~40%), Podocarpus- Prumnopitys (~12%), Araucaria (~9%), Agathis/Wollemia (~5%), Lagarostrobos (4%) and Casuarinaceae (~5%). Late Oligocene/Middle P. tuberculatus Zone assemblages preserved at the base of the Morwell 1B Seam are dominated by Myrtaceae and Elaeocarpaceae. Higher in the same section, the microfloras are dominated by Nothofagus (Brassospora) spp. with frequent to common Myrtaceae, Casuarinaceae and Elaeocarpaceae, and occasional high values of Lagarostrobos (Fig. 14.6 in Blackburn and Sluiter, 1994). Values of Myrtaceae and Lagarostrobos increase at the expense of Nothofagus (Brassospora) spp. in the Early Miocene/Upper P. tuberculatus Zone Morwell 1A Seam. Acacia and Guettarda (Rubiaceae) are recorded for the first time in this zonule. A correlative microflora from Hapuku-1 (9182 ft.) is dominated by Nothofagus (Brassospora) spp. with lesser amounts of Lagarostrobos, Podocarpus-Prumnopitys and Casuarinaceae. Rare taxa include Lophosoria, Phyllocladus and Winteraceae. c. Late Early to ~early Late Miocene Nothofagus (Brassospora) continued to dominate (30 to >50%) offshore and (Yallourn Formation) onshore microfloras during late Early to Middle (or early Late) Miocene Canthiumidites bellus Zone time although values decline relative to some temperate gymnosperms and sclerophyll angiosperms. For example, sporadically common taxa in the lower part of the Yallourn Formation include Gleicheniaceae (up to 10%), Banksia/Dryandra (up to 8%), Casuarinaceae (10-30%), Ericales (up to 12%), Myrtaceae and Proteaceae (2-10%), and Restionaceae (up to 35%). The only frequent to common gymnosperms are Lagarostrobos and Podocarpus-Prumnopitys. Uncommon to rare taxa include Cyathea, Podocarpaceae (Dacrycarpus, Dacrydium, Phyllocladus), Araliaceae, Cunoniaceae, Cupanieae, Elaeocarpaceae, Loranthaceae, Myrtaceae (Austromyrtus-type, Syzygium-type), Nothofagus (Fuscospora) spp., N. (Lophozonia) spp., Quintinia, Sapotaceae and probable members of the Rhamnaceae, Rosaceae, Rutaceae families. Canthiumidites bellus Zone microfloras in Hapuku-1 encompass Foram Zone F to Foram Zone B-2 time (A.D. Partridge pers. comm.). Rare taxa which first appear in the interval include (modern equivalents in parentheses) the wet forest ferns Rugulatisporites cowrensis (Calochlaena/Culcita) and Polypodiaceoisporites tumulatus (possibly extinct Pteris), herbs such as Tubulifloridites antipodica (Asteraceae) and Haloragacidites haloragoides (Gonocarpus/Haloragis), and at least one small rainforest tree Symplocoipollenites austellus (Symplocos). Nothofagus (Brassospora) spp. values appear to be lower (8-11%) than in the Proteacidites tuberculatus Zone. Taxa that are consistently frequent to common are Blechnaceae (up to 4%), Dicksoniaceae spp. (up to 9%), Araucariaceae (23-34%), Dacrydium (up to 4%), Lagarostrobos (up to 8%), Podocarpus-Prumnopitys (7-10%), Eucalyptus (up to 2%) and Nothofagus (Lophozonia) spp. (up to 3%). Rare taxa include Dicksonia (Matonisporites, Trilites tuberculiflormis), Phyllocladus, Mimosaceae (Acacia), Sapindaceae (Dodonaea), Symplocos and Winteraceae. One sample included pollen of a possible Nypa 263
species (Spinizonocolpites uvatus) in association with unusually abundant Lophosoria (~12%). Inferred climate Oligo-Miocene climates were uniformly wet to very wet (perhumid) but characterised by marked variations in mean temperatures. For example, the extinction of thermophilous taxa at the Eocene-Oligocene boundary (Middle/Upper Nothofagidites asperus Zone boundary) is consistent with an abrupt drop in mean temperatures to microtherm values. Subsequent trends point to gradual warming during the Early Oligocene-Early Miocene with maximum warmth (mesotherm range) being achieved in the late Early or Middle Miocene. Mean annual temperature values appear to have remained within the lower mesotherm range during the late Early to late Miocene but it is possible that warm SSTs allowed a relative of the tropical mangrove palm Nypa to migrate into the Gippsland Basin. The record is an interesting one given the sporadic appearance of warm water benthic foraminifera in southern Australia during the Middle Miocene (B. McGowran pers. comm.). The relative decline in Nothofagus (Brassospora) spp. (Fig. 2 in Sluiter and Kershaw 1982) and increasing representation of taxa typical of low/open community types suggests rainfall may have become more seasonal at about the same time. Nonetheless moisture levels remained adequate to support possibly extensive Lagarostrobos swamp forests into the early Late Miocene. 4.2.7 Tasmania For reasons that remain unclear many of the Early Tertiary palaeochannels that preserve macrofossil deposits in Tasmania became infilled (and possibly buried) during Oligo-Miocene time. The combined macrofossil and microfossil record is unusually comprehensive, both in terms of geographic coverage relative to the size of the island and in numbers of taxa able to be identified to genus or species level. Only in exceptional cases are independent age control available and it remains uncertain if the taxa used to distinguish Proteacidites tuberculatus and Canthiumidites bellus Zone Equivalent time in the Gippsland were present in the flora of inland northern and southern Tasmania during the Oligo-Miocene. For example, the earliest known record of one important accessory species of the Canthiumidites bellus Zone (Symplocoipollenites austellus) is Late Pliocene. Consequently some floras and sites dated as Early Oligocene to late Early Miocene may prove to be late Early to early Late Miocene. 1. Bass Basin Martin (1985) has provisionally identified Proteacidites tuberculatus Zone Equivalent microfloras in Squid-1 (1400-1855 m) and Tasmanian Devil-1 (600-750 m), Bass Basin. Range chart data indicate the microfloras are wholly dominated by Nothofagus (Brassospora) spp. Rare taxa include Araucaria, Dacrydium, Lagarostrobos, Cupanieae, Nothofagus (Lophozonia), Polygalaceae and (diverse) Proteaceae. Lophosoria was not recorded. Harris (1965c) has recorded Lophosoria in a probable Proteacidites tuberculatus Zone Equivalent microflora from Cape Barren Island off the northeastern coast of Tasmania. This assemblage is unusual in that it includes Dacrycarpus, Dacrydium, Phyllocladus, Beauprea, Cupanieae and Nothofagus (Brassospora) spp. but not Lagarostrobos or Podocarpus- Prumnopitys. Araucariaceae are absent. Inferred climate The assemblages are depauperate versions of correlative microfloras preserved in the Gippsland Basin. Without access to quantitative data, it is difficult to determine whether the 264
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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
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1. TIME SLICE T-1 Age Range: Paleoc
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also include relatively frequent No
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Inferred climate Some differences b
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Microfloras preserved in the Lower
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subtropical affinities are rare, hi
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Page 216 and 217: Inferred climate Climates appear to
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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 254 and 255: (Morgan 1977, McMinn 1981a, Martin
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 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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