Search

Palynology is used to provide new age controls for the coastal exposures yielding Early Cretaceous vertebrate faunas in the Otway and Gippsland basins, southeast Australia. This work shows all vert...

A new mid-latitude terrestrial climate proxy record is presented for southeastern Australia. The Middle Eocene to Middle Miocene palynofloral and δ13C record of the Latrobe Group, Gippsland Basin, details that the climate of southeastern Australia, paleolatitude 60–50°S, supported the growth of highly diverse subtropical to cool-temperate rainforests. These forests are characterized by mesothermal to microthermal floral elements that are here interpreted as subtropical (Malvacipollis subtilis and Cupanieidites orthoteichus dominated palynofloras), warm-temperate (Beaupreadites elegansiformis and Phyllocladus mawsonii dominated palynofloras) and cool-temperate (Nothofagus spp. and Dacrycarpidites australiensis dominated palynofloras) rainforests. The palynofloral record of the Latrobe Group indicates that mean annual temperatures were between 20 and 24 °C during the Middle Eocene resulting in subtropical rainforests, between 14 and 20 °C for the late Middle Eocene to earliest (i.e. pre-Oi1) Oligocene resulting in warm-temperate rainforests, between 10 and 14 °C for the late Early Oligocene to Early Miocene resulting in cool-temperate rainforests and between 14 and 20 °C in the Middle Miocene, facilitating the resurgence of warm-temperate rainforest floras. Rainfall was also likely in excess of 1500 mm throughout the Middle Eocene to the Middle Miocene in southeastern Australia. The climatic trends preserved within this mid-latitude terrestrial record relate to global Cenozoic cooling, the exception being the Middle Miocene records, which instead relate to the Middle Miocene Climatic Optimum. In the mid-latitude Gippsland Basin, cooling appears to have begun in the Middle Eocene. Correlation of our palynoflora with records from Antarctica and New Zealand, in addition to benthic δ18O records, reaffirms that the Latrobe Group coals provide a long-term, largely authochthonous mid-latitude floral record that directly relates to global climatic evolution through the Cenozoic. Our new mid-latitude terrestrial record provides critical insight into the validation of Eocene-Oligocene climate models and improves our understanding of mid-latitude terrestrial ecosystem responses to increased carbon dioxide forcing. The correlation between the δ13C values of the Yallourn and Morwell coal seams to benthic δ13C records also highlights that a relationship exists between the terrestrial and marine benthic δ13C record.

New palynological analysis of the Middle Eocene to Middle Miocene Latrobe Group coals of the Gippsland Basin in Australia sheds new light on fire adaptation in Australia's modern flora. The distribution of charcoal and fire-prone flora within brown coals is entirely controlled by facies and the paleoenvironments within the peatland, and does not result from drier climates as has been previously suggested. There is therefore, no evidence of climatic drying from this Cenozoic peatland record. Charcoal and fire-prone floras are associated with emergent and meadow marsh environments that produce darker coal lithotypes. Counter-intuitively, the low-nutrient and fire-prone environments that fringed the ever-wet rainforests of the Latrobe Group peatlands may have represented an ideal setting for southeastern Australia's modern fire-adapted and sclerophyllous flora (i.e., Eucalyptus and Banksia) to evolve in.

The Cenozoic spore-pollen zonation scheme of southeastern Australia is used to constrain the ages of marine and terrestrial strata throughout Australasia. New palynological, strontium isotope and foraminiferal data from the Torquay and Gippsland basins in southeastern Australia are here used to revise and chronologically calibrate the Oligocene and Miocene portions of this scheme. The revised age assigned to the Upper Nothofagidites asperus/Lower Proteacidites tuberculatus zonal boundary is 30.5–31.2 Ma, the Lower/Middle P. tuberculatus zonal boundary is 23.03 Ma, the Middle/Upper P. tuberculatus zonal boundary is approximately 21.1 Ma and the Upper P. tuberculatus/Triporopollenites bellus zonal boundary is 17.54 Ma. This revision confirms that a near-continuous Early Miocene neritic sequence is present in the Torquay Basin. The new ages also suggest that the timing of coal seam deposition in the Latrobe Valley was episodic, rather than continuous as has previously been interpreted. We propose that abrupt changes in moisture content across seam boundaries are associated with stratigraphic gaps. The new age controls facilitate more accurate comparisons of time-equivalent paleobotanical material throughout the southern hemisphere. The refinements presented will improve future Cenozoic paleoclimatic and paleobotanical reconstructions concerning Australia, New Zealand, South America and Antarctica.

Lower Cretaceous (Barremian to Albian) fossil plant assemblages are preserved in sediments of the Otway Group, Otway Basin, and contemporaneous Strzelecki Group, Gippsland Basin, southeastern Australia. Detailed lithofacies and biofacies analyses of terrestrial strata within the upper Eumeralla Formation (Albian), Otway Group, allow fine-scale interpretation of braided fluvial and paludal depositional environments throughout the succession. The previously described flora is re-assessed in light of changes in depositional style and plant communities to describe six Albian biofacies. Forests in the highlands are dominated by Araucariaceae conifers, which turn over to Podocarpaceae and Cheirolepidiaceae forests on the dry, raised areas in the lowlands. Ferns and angiosperms inhabit the moist floodplains and water ferns and lycophytes dwell in the ox-bow lakes. Significant changes occur between floral communities characteristic of riparian, levee and floodbasin settings through the Early Cretaceous. Albian floras are characterized by the dominance of broad-leafed araucarian conifers, an understory of diverse ferns and a dearth of seedferns and angiosperms. There is a notable absence of macrofossil ginkgoaleans in the Eumeralla Formation, although they reappear in younger (Turonian) deposits in southeastern Australia, but angiosperms are extremely scarce as macrofossils compared to the diversity recently recorded in the pollen record. Abundant charcoal demonstrates that fire continued to be a significant environmental factor at high latitudes during the middle to late Albian. The discovery of dinoflagellate species supports an earlier marine incursion and increased coastal environments, probably inhabited by cheirolepids, across the Otway Basin. Palaeontological, palynological and sedimentological data has provided a synthesis of the region's warm, high-latitude, palaeoclimatic setting in the Albian stage of the Early Cretaceous when compared to the cooler Barremian to Aptian.

The Lower Cretaceous Strzelecki Group forms the basement to the eastern part of the Gippsland Basin, but is exposed in the west and forms spectacular outcrops, especially along the coastal area between San Remo and Inverloch. The coastal area is highly faulted and lacks stratigraphic markers so matching sections in different fault blocks based only on lithology has not been possible. A combination of mapping, detailed logging, vitrinite reflectance measurements and palynology were used to determine the present-day thickness of the coastal sections and the amount of erosion that occurred during the Late Cretaceous. A total thickness of about 1500 m is inferred between Harmers Haven and Inverloch but because of the amount of faulting and probable repeated sections, the true thickness of Strzelecki Group exposed in the coastal outcrops is only about 300 m. Based on palynology and vitrinite reflectance results, the reconstructed Strzelecki Group stratigraphy has been subdivided into three distinct ‘bi...

A detailed examination of the brown coal facies preserved in the Latrobe Valley Morwell 1B seam indicates that the type of peat-forming environment and the associated hydrological regime are the main factors influencing the development of lithotypes in brown coal deposits. New palynological data from the Morwell 1B seam suggests that each respective lithotype in the lightening-upwards lithotype cycles was deposited in a particular depositional environment that was characterised by a distinct floral community. The laminated dark lithotype represents a fire-prone emergent marsh that grew on the margins of a coastal lagoon and/or freshwater swamp. This facies grades into the dark lithotype, representing the transition from a meadow marsh to a periodically flooded ombrogenous forested bog. The medium and lighter lithotypes are interpreted as being deposited in an angiosperm-dominated ombrogenous forest bog that was intolerant of fire. These peat-forming environments are interpreted as being largely controlled by moisture and relative depth to water table. Each environment produces distinct lithotypes and lightening-upwards cycles are interpreted as terrestrialization cycles. As the peat grew upwards and above the water table, less moist conditions prevailed and lighter lithotypes were produced. The observed change in colour, from darker to lighter lithotypes, results from the environment evolving from anaerobic/inundated to less anaerobic/less moist settings via terrestrialization. The thin and laterally extensive light and pale lithotypes that top the cycles are interpreted to represent a residual layer of concentrated, oxidation resistant peat-forming elements that result from intense weathering and aerobic degradation of the peats. At a generic level, modern lowland bogs of South Westland in New Zealand have remarkably similar floral/ecological gradients to those of the Oligo-Miocene Morwell 1B brown coal cycles in Australia. This suggests that modern New Zealand bogs can be used as floral/ecological analogues in order to better understand these Oligo-Miocene peatland environments.

The bathyal Ocean Drilling Program Site 765 at 5725 m water depth, offshore northwest Australia at 16°S is directly under the influence of the Australian monsoon during the Austral summer and is the recipient of continental dust during the Austral winter. It is downstream of the Indonesian Throughflow, which is a major arm of the global thermohaline circulation. As such it is ideally situated to record the climate and oceanic consequences of Quaternary climate variability. Despite being over 400 km from northwest Australia, palynomorphs (pollen and spores) are relatively common in this section, sourced via aeolian (during the dry winter) and benthic transportation processes and sediment plumes (during the summer monsoon). Detailed palynological analyses of this flora in the upper part of this core reveals intermittent snap shots of environmental and climate change over the last 300 kyrs. Interglacial stages are interpreted to be characterised by palynomorph-rich turbidite and calcareous ooze deposition whereas palynomorph-poor slowly accumulating siliceous oozes (deposited below the Calcium Carbonate Compensation Depth) are present during glacials. The dominance of Poaceae sourced from the Australian mainland in interglacial periods suggests that vegetation during these periods was similar to today. Interglacial palynofloral assemblages suggest a more intense wet season (Australian monsoon) with higher rainfall that allowed more active erosion and deposition onto the shelf. The presence of Indonesian sourced pollen and fern spore taxa, as well as warm water dinoflagellate species suggest enhanced Leeuwin Current and monsoonal intensity during interglacials times. The youngest part of the core is dominated by siliceous ooze, likely deposited during the Last Glacial Maximum and the early Holocene. The lack of calcareous ooze near the top of the core is likely caused by Holocene to Recent erosive processes or core disturbance. The presence of common charcoal in all samples over the last 300 kyrs shows that fire was a constant feature of the landscape in northwest Australia prior to human occupation of the region 65,000 years ago.

The cyclic succession of brown coals in the Latrobe Valley, Gippsland Basin, Australia, records an exceptional floral and charcoal record from the Late Oligocene to Middle Miocene. New palynological, geological and charcoal data are consistent with existing colourimetry, carbon isotope, and organic geochemical and palaeobotanical data, indicating that the repeated lithotype cycles represent relative drying (terrestrialization). Based on this detailed palynological study, the vegetation succession within the Latrobe Valley peatlands is interpreted to have begun with a fire-prone emergent marsh of bulrushes (Typhaceae), which grades landward into a fire-prone meadow marsh of rushes (Restionaceae), heaths (Ericaceae) and coral-ferns (Gleicheniaceae). This marsh environment then developed into a forested bog, with gymnosperms (e.g. the Podocarpaceae Dacrycarpus and Dacrydium ) as the dominant trees, until an ombrogenous forest bog developed, predominantly consisting of angiosperms (e.g. Nothofagus , Quintinia ). The similarity between vegetation successions in New Zealand and the lightening-upwards cycles from the Latrobe Valley coals suggests that New Zealand's modern vegetation communities represent a floral analogue for the successions preserved in the Latrobe Valley coals. High abundances of micro and macro charcoal recorded in the darker lithotypes, within the lithotype cycles of the M1B and M2A seams, suggest that the Latrobe Valley peatlands were subject to repeated fires during the Late Oligocene to Early Miocene.

This study provides the first record of the high diversity and abundance of Victoria's earliest angiosperms from outcrops in the non-marine upper Eumeralla Formation of the Otway Basin. The biostratigraphic schemes established for the Albian of Australia are re-evaluated using more reliable and widespread index species, resulting in the construction of a high-resolution Albian biostratigraphy in the Otway Basin. New localities in the uppermost outcrop of the Eumerella Formation contain spore–pollen assemblages that cannot be placed in the existing scheme and a new Upper Phimopollenites pannosus Subzone is recognised. The correlation of the P. pannosus Zone to the geochronological timescale was re-assessed and shows that it is 103–101.51 Ma, giving a late Albian age. In contrast to previous studies that record low diversity angiosperm assemblages in the Albian, this study identifies twenty-three angiosperm species, including one new species, Tricolpites tortuous. The high diversity and abundance of angiosperm pollen in the Otway Basin provides further evidence that angiosperms probably migrated into eastern Gondwana via South America and Antarctica.

Rich, T.H., Hopson, J.A., Gill, P.G., Trusler, P., Rogers-Davidson, S., Morton, S., Cifelli, R.L., Pickering, D., Kool, L., Siu, K., Burgmann, F.A., Senden, T., Evans, A.R., Wagstaff, B.E., Seegets-Villiers, D., Corfe, I.J., Flannery, T.F., Walker, K., Musser, A.M., Archer, M., Pian, R. & Vickers-Rich, P., June 2016. The mandible and dentition of the Early Cretaceous monotreme Teinolophos trusleri. Alcheringa 40, xx–xx. ISSN 0311-5518.The monotreme Teinolophos trusleri Rich, Vickers-Rich, Constantine, Flannery, Kool & van Klaveren, 1999 from the Early Cretaceous of Australia is redescribed and reinterpreted here in light of additional specimens of that species and compared with the exquisitely preserved Early Cretaceous mammals from Liaoning Province, China. Together, this material indicates that although T. trusleri lacked a rod of postdentary bones contacting the dentary, as occurs in non-mammalian cynodonts and basal mammaliaforms, it did not share the condition present in all living mammals, including...

The Early Cretaceous high-paleolatitude palynofloras from the Otway and Gippsland basins of southeastern Australia contain diverse angiosperm assemblages not described previously. Clavatipollenites hughesii recovered from the early Aptian Upper Cyclosporites hughesii subzone in the Gippsland Basin represents the first record of angiosperm pollen in Australia, coeval to records recovered from the Great Artesian and North West Shelf basins of northern Australia. Tricolpate pollen including Tricolpites variabilis, Rousea georgensis and Striatopollis spp., are first recorded in the late Albian Upper Coptospora paradoxa subzone in southeastern Australia. This represents the second oldest occurrence of tricolpate pollen in Australia, the first occurring in the older middle Albian Lower Coptospora paradoxa subzone in the northern Great Artesian Basin. By the latest Albian Phimopollenites pannosus Zone angiosperms had diversified rapidly in southeastern Australia. The delayed appearance, rise in abundance and diversification of eudicot angiosperms in the high-latitude southern basins of Australia, relative to low- and mid-latitude settings, supports a latitudinally diachronous pattern of angiosperm range expansion from warmer paleoequatorial regions to relatively cooler high-latitude settings. Increasing mean annual temperatures globally in the late Albian likely facilitated the expansion of angiosperms into high-latitude settings in the Southern and Northern hemispheres.

Poropat, S.F., Martin, S.K., Tosolini, A.-M.P., Wagstaff, B.E, Bean, L.B., Kear, B.P., Vickers-Rich, P. & Rich, T.H., May 2018. Early Cretaceous polar biotas of Victoria, southeastern Australia—an overview of research to date. Alcheringa 42, 158–230. ISSN 0311-5518. Although Cretaceous fossils (coal excluded) from Victoria, Australia, were first reported in the 1850s, it was not until the 1950s that detailed studies of these fossils were undertaken. Numerous fossil localities have been identified in Victoria since the 1960s, including the Koonwarra Fossil Bed (Strzelecki Group) near Leongatha, the Dinosaur Cove and Eric the Red West sites (Otway Group) at Cape Otway, and the Flat Rocks site (Strzelecki Group) near Cape Paterson. Systematic exploration over the past five decades has resulted in the collection of thousands of fossils representing various plants, invertebrates and vertebrates. Some of the best-preserved and most diverse Hauterivian–Barremian floral assemblages in Australia derive from outcrops of the lower Strzelecki Group in the Gippsland Basin. The slightly younger Koonwarra Fossil Bed (Aptian) is a Konservat-Lagerstätte that also preserves abundant plants, including one of the oldest known flowers. In addition, insects, crustaceans (including the only syncaridans known from Australia between the Triassic and the present), arachnids (including Australia’s only known opilione), the stratigraphically youngest xiphosurans from Australia, bryozoans, unionoid molluscs and a rich assemblage of actinopterygian fish are known from the Koonwarra Fossil Bed. The oldest known—and only Mesozoic—fossil feathers from the Australian continent constitute the only evidence for tetrapods at Koonwarra. By contrast, the Barremian–Aptian-aged deposits at the Flat Rocks site, and the Aptian–Albian-aged strata at the Dinosaur Cove and Eric the Red West sites, are all dominated by tetrapod fossils, with actinopterygians and dipnoans relatively rare. Small ornithopod (=basal neornithischian) dinosaurs are numerically common, known from four partial skeletons and a multitude of isolated bones. Aquatic meiolaniform turtles constitute another prominent faunal element, represented by numerous isolated bones and articulated carapaces and plastrons. More than 50 specimens—mostly lower jaws—evince a high diversity of mammals, including monotremes, a multituberculate and several enigmatic ausktribosphenids. Relatively minor components of these fossil assemblages are diverse theropods (including birds), rare ankylosaurs and ceratopsians, pterosaurs, non-marine plesiosaurs and a lepidosaur. In the older strata of the upper Strzelecki Group, temnospondyl amphibians—the youngest known worldwide—are a conspicuous component of the fauna, whereas crocodylomorphs appear to be present only in up-sequence deposits of the Otway Group. Invertebrates are uncommon, although decapod crustaceans and unionoid bivalves have been described. Collectively, the Early Cretaceous biota of Victoria provides insights into a unique Mesozoic high-latitude palaeoenvironment and elucidates both palaeoclimatic and palaeobiogeographic changes throughout more than 25 million years of geological time. Stephen F. Poropat*† [sporopat@swin.edu.au;stephenfporopat@gmail.com], Faculty of Science, Engineering and Technology, Swinburne University of Technology, John St, Hawthorn, Victoria 3122, Australia; Sarah K. Martin*‡ [sarah.martin@dmirs.wa.gov.au;martin.sarahk@gmail.com] Geological Survey of Western Australia, 100 Plain St, East Perth, Western Australia 6004, Australia; Anne-Marie P. Tosolini [a.tosolini@unimelb.edu.au] and Barbara E. Wagstaff [wagstaff@unimelb.edu.au] School of Earth Sciences, The University of Melbourne, Melbourne, Victoria 3010, Australia; Lynne B. Bean [lynne.bean@anu.edu.au] Research School of Earth Sciences, Australian National University, Acton, Canberra, Australian Capital Territory 2001, Australia; Benjamin P. Kear [benjamin.kear@em.uu.se] Museum of Evolution, Uppsala University, Norbyvägen 16, Uppsala SE-752 36, Sweden; Patricia Vickers-Rich§ [prich@swin.edu.au;pat.rich@monash.edu] Faculty of Science, Engineering and Technology, Swinburne University of Technology, John St, Hawthorn, Victoria 3122, Australia; Thomas H. Rich [trich@museum.vic.gov.au] Museum Victoria, PO Box 666, Melbourne, Victoria 3001, Australia. *These authors contributed equally to this work. †Also affiliated with: Australian Age of Dinosaurs Museum of Natural History, Lot 1 Dinosaur Drive, PO Box 408, Winton, Queensland 4735, Australia. ‡Also affiliated with: Earth and Planetary Sciences, Western Australian Museum, Welshpool, Western Australia 6101, Australia. §Also affiliated with: School of Earth, Atmosphere and Environment, Monash University, Melbourne, Victoria 3800, Australia.

Cheirolepidiaceae leaves and pollen are recorded from Valanginian–Albian strata of southeastern Australia that were deposited at high-latitudes under cool, moist climates in contrast to the semi-arid or coastal habitats preferred by many northern Gondwanan and Laurasian representatives of this group. Leaves of this family are characterized by thick cuticles and cyclocytic stomata with randomly oriented apertures, arranged in scattered or longitudinal rows or bands. Stomata are deeply sunken and surrounded by four to six subsidiary cells that bear one or two ranks of prominent overarching papillae, which may constrict the mouth of the pit. Three new taxa (Otwayia denticulata Tosolini, Cheirolepidiaceae cuticle sp. A and sp. B) are distinguished based on cuticular features, adding to several previously documented cheirolepid conifers in the Early Cretaceous of eastern Australia. Cheirolepidiaceae foliage is preserved predominantly in fluvial floodbasin settings and is interpreted to be derived from small trees occupying disturbed or low-nutrient sites. The foliage is associated with Classopollis/Corollina pollen and roots characterized by prominent mycorrhizal nodules. A Cenomanian Classopollis type recognised from Bathurst Island, Northern Australia, is recorded for the first time from the Early Cretaceous Eumeralla Formation, Otway Basin. Classopollis locally is rare in Valanginian–Barremian strata of Boola Boola, Gippsland, but constitutes up to 14% of the palynomorph assemblage in Albian strata. This indicates that the family was locally abundant in cool southern high-latitude climates of the Mesozoic, contrary to previous reports of its rarity in this region. Reconstructing the lost forests of Antarctica: the palaeoecology, anatomy and phylogeny of the iconic Glossopteris flora Exceptional permineralized biotas - windows into the evolution and functional diversity of terrestrial ecosystems through time

Lithotype cycles (ranging from 10 to 30 m thick) in the brown coals of the Latrobe Valley, Gippsland Basin, Australia, display well-developed lightening-upward trends. Cycle tops are characterized by abrupt and unconformable boundaries with the overlying cycle. Geological, geochemical, palynological and macrofossil evidence is consistent with a relative drying (terrestrialization) upward depositional model for the cycles. The abundance of charcoal in dark lithotypes near the cycle bases is explained by the fire-prone and highly flammable nature of the herbaceous/reed wetlands, in common with similar modern wetlands in modern Australasia, in which the dark lithotypes are suggested to have formed. This, together with the greater preservation potential of charcoal in subaqueous environments, results in the wettest facies of the Latrobe Valley coals having the highest charcoal contents. Despite prevailing warm, wet climate conditions and the predominance of rainforests that are suggested to have characterized the Cenozoic of southern Australia, some swamp taxa were clearly already pre-adapted to tolerate fire and are likely to have been the ancestors of the fire-adapted floral communities of modern arid Australia.

An early Eocene (52 ± 2 Ma) flora from the Mwadui kimberlite pipe in Tanzania includes ten leaf morphotypes, small seeds, fossil wood putatively related to Cynometra (Detarieae, Fabaceae), and a sparse palynoflora. The leaf flora is characterised by microphyllous and notophyllous entire margined leaves that are suggested to be related to the Euphorbiaceae and Fabaceae, although many cannot be firmly placed in modern families. The wood is the oldest member of Cynometroxylon and confirms that the Detarieae were diverse by the early Paleogene. The palynoflora is dominated by Ailanthipites daedaleus and Triporopollenites mwaduiensis with lesser amounts of small tricolpate ( Tricolpites ) and monosulcate ( Lilliacidites ) grains together with spores ( Cyathidites spp., Triporoletes laevigatus ) and freshwater algal cysts. Other components of the palynoresidue include abundant charcoalified tracheids and fungal hyphae. The low diversity and sparse palynoflora suggests a restricted catchment with little input from the regional vegetation. The sediments accumulated in a freshwater lacustrine environment with palynological input from the crater walls that were covered by low diversity vegetation. This is supported by the leaf floras. Although the leaf floras are more diverse with nine morphotypes identified, the small leaves (microphyll to notophyll) suggest a water-limited palaeoenvironment. This is supported by the low diversity and abundance of fern and bryophyte spores. The presence of a single wood taxon not only indicates that there were large trees around the crater-lake but that the aboreal component was of low diversity. These observations suggest an open woodland-like setting, while the taxonomic affinities of the wood ( Cynometra ) suggest a humid microclimate possibly with marked wet–dry seasonal contrasts.

Detailed “Quaternary-style” quantitative spore–pollen counts, with a pollen sum based on total non-angiosperm seed plants, from a southern high palaeolatitude (60–65°) terrestrial sequence in Gippsland, southeast Australia has revealed strong vegetation and climate variability during the Albian. This variability is more pronounced than previously suggested in global Early Cretaceous vegetation and climate reconstructions. The quantitative spore–pollen record shows drying throughout the Albian based on upward decreasing total ferns and variation in podocarp and total Alisporites/Vitreisporites pollen. This record suggests that although global climate during the Albian is considered to have been warm, stable and equable, regional factors such as water availability and continentality were the main drivers of this vegetation change.

The Albian spore-pollen zonation of Australia is used to date terrestrial sequences from Antarctica to New Zealand. A detailed qualitative and quantitative study of the Albian Crybelosporites striatus and Coptospora paradoxa Zones in the Gippsland Basin confirms many of the published zone indicator taxa are reliable. The first and last appearance datums can be further refined quantitatively based on the upward reduction in the abundance of seed fern produced pollen. Three subzones are defined in the C. paradoxa Zone using a combination of presence/absence range and abundance data. These are (from oldest to youngest): the Trilobosporites trioreticulosus , Pilosisporites grandis and Cicatricosisporites cuneiformis Subzones. This latter subzone presents a new subdivision of this zone in the Gippsland Basin in southeast Australia. All these subzonal divisions have sufficient resolution to facilitate reservoir-scale correlation of fluvial strata confined to the C. paradoxa Zone in the Gippsland Basin. This study has the first record of Taxodiaceaepollenites hiatus in the Early Cretaceous of Australia and a new species Aequitriradites burgerii is described. A re-examination of the chronology of the zones in the Cretaceous marine basins confirms a 103.5 Ma age for the top of the C. paradoxa Zone, however the chronology of the base of this zone is unclear in the Albian.

Imagery of meandering river-like channel features up to 5 m deep and 100 m wide on the floor of Port Phillip Bay have been revealed by recent multibeam surveys. They are in water depths to −22 m below the present bay water level. This young channelling overlies older infilled Pleistocene–early Holocene channels considered to be cut by the Yarra and Werribee rivers during the last glacial or previous low stand minima >10 000 cal. yr BP and infilled during the Holocene transgression. Vibrocoring data indicate the young channels incise shelly mud. Twelve 14C shell dates in vibrocores from bay floor to 3.5 m are in two units—a lower unit range between 2880 cal. yr BP at 0.7 m to 9491 cal. yr BP at 3.5 m, and an upper unit ∼0.5 to 0.7 m thick

The carbon-isotope and palynological record through 580 m thick almost continuous brown coal in southeast Australia's Gippsland Basin is a relatively comprehensive southern hemisphere Middle Eocene to Middle Miocene record for terrestrial change. The carbon isotope δ13Ccoal values of these coals range from − 27.7‰ to − 23.2. This isotopic variability follows gymnosperm/angiosperm fluctuations, where higher ratios coincide with heavier δ13C values. There is also long-term variability in carbon isotopes through time. From the Eocene greenhouse world of high gymnosperm-heavier δ13Ccoal values, there is a progressive shift to lighter δ13Ccoal values that follows the earliest (Oi1?) glacial events around 33 Ma (Early Oligocene). The overlying Oligocene–Early Miocene brown coals have lower gymnosperm abundance, associated with increased %Nothofagus (angiosperm), and lightening of isotopes during Oligocene cooler conditions. The Miocene palynological and carbon-isotope record supports a continuation to the Oligocene trends until around the late Early Miocene (circa 19 Ma) when a warming commenced, followed by an even stronger isotope shift around 16 Ma that peaked in the Middle Miocene when higher gymnosperm abundance and heavier isotopes prevailed. The cycle between the two major warm peaks of Middle Eocene and Middle Miocene was circa 30 Ma long. This change corresponds to a fall in inferred pCO2 levels for the same period. The Gippsland data suggest a link between gymnosperm abundance, long-term plant δ13C composition, climatic change, and atmospheric pCO2. Climatic deterioration in the Late Miocene terminated peat accumulation in the Gippsland Basin and no further significant coals formed in southeast Australia. The poor correspondence between this terrestrial isotope data and the marine isotope record is explained by the dominant control on δ13C by the gymnosperm/angiosperm abundance, although in turn this poor correspondence may reflect palaeoclimate control. From the brown coal seam dating, the coal appears to have accumulated during a considerable part of the allocated 30 Ma Cenozoic time period. These brown coal carbon isotope and palynological data appear to record a more gradual atmospheric carbon isotope change compared to the marine record.

Since the idea of the Pliocene Kosciusko Uplift in the Southeastern Highlands of Australia was first introduced, there has been considerable debate about the validity of this Cenozoic uplift event. Until the mid 1990s, most researchers argued that most highland relief was present by the Cretaceous. Since the late 1990s, there has been a paradigm shift that extensive young Cenozoic uplift created much of the high relief. In this paper, we synthesise Cenozoic stratigraphic and structural data from the East Victoria Highlands to assess the timing and origin of uplift. New high-resolution radar topography data indicate extensive east-northeast- and northeast-trending vertical and horizontal fault block displacement of the Cenozoic volcanic and sedimentary paleovalley infill. We suggest that regional uplift and exhumation of the East Victoria Highlands took place along these faults, initiated during the Late Eocene to Early Oligocene, and movements continue to the present day. By a combination of block faultin...

A palynological study of oil exploration wells in the Gippsland Basin southeastern Australia has provided a record of southern high latitude climate variability for the last 12 million years of the Cretaceous greenhouse world. During this time, the vegetation was dominated by a cool to temperate flora of Podocarpaceae, Proteaceae and Nothofagidites spp. at a latitude of 60°S. Milankovitch forced cyclic alternations from drier to wetter climatic periods caused vegetation variability from 72 to 77 Ma. This climate change was probably related to the waxing and waning of ephemeral (100 ky) small ice sheets in Antarctica during times of insolation minima and maxima. Drying and cooling after 72 Ma culminated from 68 to 66 Ma, mirroring trends in global δ 18 O data. Quantitative palynofloral analyses have the potential to provide realistic proxies for small-scale climate variability in the predominantly ice-free Late Cretaceous.

The 100-m thick Middle Miocene Yallourn brown coal seam was the last of the major Latrobe Valley Group seams to form in the Gippsland Basin (southeastern Australia) and the final major coal to form in Australia. Coal deposition coincided with the Middle Miocene climatic optimum. During this warm period of relatively high sea-levels, high water tables and relatively high subsidence rates, a 565 km 2 area of alternating eutrophic and ombrogenous peat swamp developed at the western end of the Latrobe Valley to form the Yallourn Seam. Stratigraphic units of the seam contain a high sclerophyll plant component and abundant charcoal, suggesting seasonal dry periods alternated with wet warm conditions characterised by abundant rushes and dense kauri forests. Iron content in parts of the Yallourn Seam is relatively high, and a strong correlation exists between the iron distribution and the abundance of proteoid roots (mainly Proteaceae) — an indicator of seasonal dry periods. The contemporaneous carbonates of the Wuk Wuk Marl were deposited in a high-productivity, upwelling, warmer water (subtropical) environment. A new carbon isotope profile at 1 m intervals through the Yallourn Seam shows a poor relationship between δ 13 C isotopes and coal colour, but some correlation with Gymnosperm abundance. The δ 13 C record also correlates well with long-term secular changes in climate, the presence of global carbon maxima CM2–CM4, and with the deep-sea δ 13 C marine organic record. Thick coal seam development ended near the end of the Middle Miocene climatic optimum. The termination of coal seam deposition in Latrobe Valley was primarily the result of tectonic compression, uplift and development of adjacent highland relief, and erosion at the end of the Miocene.

Basaltic eruptions across the Central Highlands of Victoria have sealed in-place Early to middle Cenozoic palaeodrainage systems (also known as deep leads). The basal gravels of the deep leads have been mined extensively in the past for their rich placer-gold deposits. Detailed mapping of the distribution of all palaeorivers has been carried out using drilling results and modern aeromagnetic/radiometric surveys. The palaeochannel isopachs (including basalt and sediment) do not thicken in a modern downvalley direction. Instead, deeper depressions alternate with shallower areas. The variations in thickness, and parts of the palaeochannel courses, are controlled by a series of east-northeast-trending basement highs. The basement highs are caused by a set of east-northeast-trending (Otway Basin-style) faults visible on radar shuttle imagery in the Central Highlands. They have not previously been recognised in regional geological mapping. Most published fault trends are north – south oriented, parallel to the ...

The Tuna Field in the Gippsland Basin southeastern Australia hosts Late Cretaceous fluvial siliciclastic oil and gas reservoirs that have proved difficult to correlate seismically. Previous correlations of the reservoir facies have been achieved using a combination of well data (wireline log, cuttings and core) and qualitative palynological data. This study integrates new detailed facies and palynological analyses that improve reservoir correlation across the Tuna Field. Specifically, investigation of the Campanian sections in Tuna-1 and Tuna-4 wells has resulted in a revision of the age assigned to the strata. In addition, the facies analyses of these two wells, supported by wireline log interpretation from several wells in the Tuna Field suggests that the reservoir intervals represent a low and high sinuosity fluvial depositional system. The revised palynological dating was enhanced by quantitative palynology leading to the identification of a biostratigraphically significant vegetation event within the Tubulifloridites (al. Tricolporites) lilliei Zone. The palynological data further shows that the regional vegetation was dominated by tree species attributable to the Podocarpaceae, Araucariaceae, Proteaceae and Nothofagus spp. (ancestral type). However, this canopy was not as stable as previous authors have suggested, and the vegetation events that help in the correlation further suggest times of small-scale climate variation within the Campanian.

This book provides a critical appraisal of ecosystem theory using case studies of biological invasions in Australasia.

▪ Abstract The Araucariaceae are important to biogeography because they have an ancient origin and are a distinctive and sometimes dominant component of southern hemisphere forest communities. This paper examines recent information on ecology and phylogeny and on pollen and macrofossil assemblages to assess the history and present-day status of the family and its potential for refinement of past environmental, particularly climatic, conditions. From an origin in the Triassic, the family expanded and diversified in both hemispheres in the Jurassic and Early Cretaceous and remained a significant component of Gondwanan vegetation until the latter part of the Cenozoic. The development of angiosperms in the Middle Cretaceous probably assisted in the demise of some araucarian components but there was also evolution of new genera. Recorded diversity in the early Cenozoic of Australia is as high as it was in the Early Cretaceous. Continental separation and associated climatic drying, cooling, and increased variability progressively reduced the ranges of conifers to moist, predominantly mesothermal climates on continents. However, tectonic and volcanic activity, partially associated with Australia's collision with Southeast Asia, provided new opportunities for some araucarian components on Asia-Pacific islands. Araucarians provide information on climatic conditions suitable for rainforest vegetation throughout their recorded period, even prior to the recognition or even existence of these forests in the fossil record. High pollen abundance is also indicative of marginal rainforest environments where these canopy emergents can compete effectively with angiosperm forest taxa. Despite their apparent relictual status in many areas, they provide precise paleoclimatic estimates in late Quaternary pollen records and have particular value in providing evidence of climatic variability that has otherwise been difficult to detect.

A discontinuous 70 m sediment core was extracted from the volcanic crater of Pejark Marsh to temporally extend the existing Quaternary record of vegetation and environments from the Western Plains of Victoria. The sequence was fission track dated to the Early–Middle Pleistocene transition. Both the sediments and the aquatic pollen indicate a general lake shallowing and progressive increase in drying and peat deposition events. The major dry land pollen taxa are similar to those that dominate the late Quaternary records from the area and indicate the alternation of regionally dominant sclerophyll forest during wetter periods and steppe or open woodlands during drier periods. A major feature of the pollen record is the presence of a number of regionally extinct taxa in the basal half of the record. Some of these taxa, including Araucaria, Canthium and Microcachrys, represent major range extensions of previously considered regionally extinct taxa into the Pleistocene. Tentative correlation with the marine oxygen isotope record suggests that the sequence may extend from isotope stages 30 to 17 with major changes within the record relating to the transition from the higher frequency, lower amplitude, orbitally forced climatic cycles of the Early Pleistocene to the lower frequency, higher amplitude cycles of the Middle–Late Pleistocene.

The basal theropod dinosaur clade Ceratosauria, and its subclade Abelisauroidea, is characteristic of late Mesozoic terrestrial vertebrate faunas in western Gondwana (South America, Africa, Madagascar, and India) and Europe. Yet unambiguous records of ceratosaurs have hitherto been absent from Australia, where the theropod assemblage appears to include several typically Laurasian clades. Here, we report the first evidence of ceratosaurs (and potentially abelisauroids) from eastern Gondwana––a diagnostic astragalocalcaneum from the Aptian (121–125 Ma) of Victoria, Australia. Ceratosauria thus occurred in both western and eastern Gondwana during the Early Cretaceous. This fossil adds to the poorly known dinosaur fauna of Australia, a major clade of basal theropods, emphasising that its mid-Cretaceous theropod diversity was surprisingly cosmopolitan despite relative geographic isolation, including clades that have been thought to be typical of both Gondwana and Laurasia––Ceratosauria, Spinosauridae, Carcharodontosauria, Tyrannosauroidea, and Deinonychosauria. Such a contemporaneous association of theropod clades is unknown from other Gondwanan continents and questions the views that the late Mesozoic dinosaur fauna of Australia was dominated by Gondwanan or Laurasian elements, extreme isolation, relictualism, and/or novelty as a ‘centre of origin’. The cosmopolitan theropod fauna of Australia probably reflects the global distribution of these clades early in their history, prior to significant continental breakup.