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Well-preserved leaf fossils from the Middle Eocene Anglesea site in Victoria are assigned to a new species of Megahertzia (M. paleoamplexicaulis R.J.Carp. & Rozefelds), a genus of Proteaceae now represented by a single species, M. amplexicaulis A.S.George & B.Hyland, in the Wet Tropics rainforests of Queensland. Megahertzia -like cuticular remains also occur in the Eocene Mount Hotham assemblage of Victoria, and pollen closely conforming to Megahertzia (i.e. Proteacidites latrobensis W.K.Harris) occurs widely in Cenozoic sediments of Australia and in New Zealand. All these records add to other fossil evidence that many species of Australian rainforest Proteaceae are the last vestiges of formerly much more widespread lineages. The fossil leaves are near-identical in architecture and cuticular features to lobed leaves of M. amplexicaulis , including that they have small teeth, stomata in well-defined areoles, and fine cuticular striations. Moreover, where preserved, the leaf fossils show amplexicaul bases, a unique (apomorphic) trait of the extant species. The apparent absence at Anglesea of simple (unlobed) leaves in Megahertzia and two other taxa of fossil Proteaceae is discussed; this leaf type could have evolved convergently in response to forest canopy heat increase as Australia drifted towards the Equator. The World Heritage Queensland Wet Tropics support an amazing 15 endemic genera of the Gondwanan Proteaceae family, including Megahertzia from the Daintree rainforest. Megahertzia -like fossil leaves were first collected from the Anglesea coal mine (Victoria, 3000 km away!) over 30 years ago, but have never been described. New fossil studies show the sole living species of Megahertzia as the last vestige of a formerly much more widespread lineage, and underscore the imperative need for conserving Australia's unique rainforest biota. [ABSTRACT FROM AUTHOR]

We describe two new genera of phymaraphiniid lithistid sponges Twertupia gen. nov. and Pickettispongia gen. nov. from the upper Eocene Pallinup Formation of South Western (SW) Australia based on new, rich and very well preserved material. Type material of these two genera, earlier described from poorly preserved material, were originally attributed to Thamnospongia subglabra and Stachyspongia neoclavatela (in case of species of Twertupia), and to Discoderma tabelliformis (case of species of Pickettispongia). This is the first record of bodily preserved phymaraphiniid sponges from Eocene rocks, as well as from the southern hemisphere. We discuss extant and fossil representatives of Phymaraphiniidae and their geographical distribution, concluding that the present day occurrences of these sponges are the result of a much larger Mesozoic Tethyan distribution. [ABSTRACT FROM AUTHOR]

During the early to middle Eocene, a mid‐to‐high latitudinal position and enhanced hydrological cycle in Australia would have contributed to a wetter and "greener" Australian continent where today arid to semi‐arid climates dominate. Here, we revisit 12 southern Australian plant megafossil sites from the early to middle Eocene to generate temperature, precipitation, and seasonality paleoclimate estimates, net primary productivity (NPP), and vegetation type, based on paleobotanical proxies and compare them to early Eocene global climate models. Temperature reconstructions are uniformly subtropical (mean annual, summer, and winter mean temperatures 19–21°C, 25–27°C, and 14–16°C, respectively), indicating that southern Australia was ∼5°C warmer than today, despite a >20° poleward shift from its modern geographic location. Precipitation was less homogeneous than temperature, with mean annual precipitation of ∼60 cm over inland sites and >100 cm over coastal sites. Precipitation may have been seasonal with the driest month receiving 2–7× less than the mean monthly precipitation. Proxy‐model comparison is favorable with a 1,680 ppm CO2 concentration. However, individual proxy reconstructions can disagree with models as well as with each other. In particular, seasonality reconstructions have systemic offsets. NPP estimates were higher than modern, implying a more homogenously "green" southern Australia in the early to middle Eocene when this part of Australia was at 48–64°S and larger carbon fluxes to and from the Australian biosphere. The most similar modern vegetation type is modern‐day eastern Australian subtropical forest, although the distance from coast and latitude may have led to vegetation heterogeneity. Plain Language Summary: Australia today is dominated by arid environments, with sparse shrubland or grassland vegetation, and forest biomes limited to areas with abundant moisture supply. These arid environments have low primary productivity and store relatively little carbon. Examination of 12 early to middle Eocene (55–40 million years old) fossil floras shows that southern Australia at that time was much "greener." In a globally warmer world and poleward positioning of southern Australia, southward of mid‐latitude high‐pressure systems, rainfall in now arid environments was much higher. What is now almost barren landscapes would have supported a much more luxurious forested biome. As a result, primary productivity was enhanced and on‐land carbon storage would have been much higher as well. This research shows that in ancient greenhouse worlds high temperatures in addition to a more active hydrological cycle can lead to an increase in carbon storage and fluxes of the terrestrial biosphere. Key Points: Early Eocene southern Australia average temperatures were over 5°C warmer than today, despite being further south than todayAverage rainfall was much higher than today, with 60 cm yr−1 inland to >100 cm yr−1 closer to the coastSouthern Australia was more homogeneously green and productive during the Eocene, in places where today arid shrub‐ and grasslands dominate [ABSTRACT FROM AUTHOR]

The Redbank Plains Formation, between Brisbane and Ipswich in South East Queensland, provides fossil evidence of the fauna and flora of the earliest part of the Cenozoic era, and is dated from the Paleogene Period, specifically the late Paleocene--early Eocene (66--55 Ma). These fossils have been collected and studied for over 120 years, but the conjunction of agriculture in the then-rural Redbank Plains district, and the mapping of the valuable Ipswich coalfields, led to their palaeontological significance being recognised and documented. Scientific study began in 1916 and has continued since, revealing some of the earliest evidence of modern Australian fauna and flora. However, the area's rich underground coal resources and a hunger for residential land in a rapidly developing urban corridor, has resulted in the loss of or threats to the fossil sites. One deposit has been given local government status as a Conservation Park and remains accessible for scientific study, but the lack of either national or state protection for such significant sites in Queensland and Australia imperils our national geological heritage and its scientific contribution. [ABSTRACT FROM AUTHOR]

The oldest carbonate sediments in the western Eucla Basin in south-western Australia are a series of cool-water bryozoan-dominated bioclastic grainstones, packstones and marls that represent deposition during the Tortachilla Transgression during the Bartonian (middle Eocene) planktonic foraminiferal zones 14-15. The two principal units are the Nanarup Limestone and a unit reported here for the first time and named, informally, the Manypeaks limestone. These units contain rich invertebrate faunas dominated by bryozoans, echinoids, bivalves and brachiopods. Herein we document fourteen echinoid species that occur in these limestones. They comprise one cidaroid, one camarodont, one salenioid, two cassiduloids, one echinolampadoid, one clypeasteroid and seven spatangoids. Four new species are described, the cassiduloid Eurhodia westaustraliae sp. nov., the clypeasteroid Fossulaster susae sp. nov., and the spatangoids Cyclaster jamiei sp. nov. and Gillechinus kaitae sp. nov. The species of Fossulaster represents the earliest known member of the Fossulasteridae and the earliest known record of a marsupiate echinoid in Australia. Analysis of the middle and late Eocene echinoids faunas of the western Eucla Basin establishes that the Nanarup Limestone echinoid fauna represents the cassiduloid biofacies, while the Manypeaks limestone is a mixed cassiduloid and spatangoid biofacies. [ABSTRACT FROM AUTHOR]

Porifera is a clade of globally distributed, early diverging metazoans that are important components of modern aquatic environments. Despite the fact that they were also abundant in the geological past, their fossil record is uneven. For example, little is known about sponge communities that inhabited the Tethyan areas during the Cenozoic. Here, we record an abundant and taxonomically diverse assemblage of middle–late Eocene sponges from east‐central Ukraine. The material consists of preserved whole‐body specimens as well as disassociated spicules. The taxonomic composition of this new assemblage, supplemented with previously published data obtained from sponge materials originating from the middle and upper Eocene of the East European Platform, documents a surprisingly rich sponge community that inhabited shallow waters (depths of 100 m) and comprised at least 30 demosponge species, including two new taxa, Paratetilla milanek Łukowiak and Theonella alexandriae Łukowiak, three hexactinellids and a single homoscleromorph. Additionally, we report the first fossil occurrence of Vetulina, a demosponge genus that currently is found near the Philippines and Australia and in the Caribbean Sea. Some of the sponge taxa recognized were previously noted from the upper Eocene of Australia and New Zealand. This is indicative of their wide distribution during the early Cenozoic and also shows that a non‐interrupted connection existed between the western Tethyan and peri‐Australian areas, explaining the patchy distribution of some sponge taxa in modern seas. [ABSTRACT FROM AUTHOR]

The Paleoproterozoic (1.7 Ga [billion years ago]) metasedimentary rocks of the Mount Barren Group in southwestern Australia contain burrows indistinguishable from ichnogenera Thalassinoides, Ophiomorpha, Teichichnus, and Taenidium, known from firmgrounds and softgrounds. The metamorphic fabric in the host rock is largely retained, and because the most resilient rocks in the sequence, the metaquartzites, are too hard for animal burrowing, the trace fossils have been interpreted as predating the last metamorphic event in the region. Since this event is dated at 1.2 Ga, this would bestow advanced animals an anomalously early age. We have studied the field relationships, petrographic fabric, and geochronology of the rocks and demonstrate that the burrowing took place during an Eocene transgression over a weathered regolith. At this time, the metaquartzites of the inundated surface had been weathered to friable sandstones or loose sands (arenized), allowing for animal burrowing. Subsequent to this event, there was a resilicification of the quartzites, filling the pore space with syntaxial quartz cement forming silcretes. Where the sand grains had not been dislocated during weathering, the metamorphic fabric was seemingly restored, and the rocks again assumed the appearance of hard metaquartzites impenetrable to animal burrowing. [ABSTRACT FROM AUTHOR]

Through new palynological and chronostratigraphic (40Ar/39Ar dating) analyses we constrain the ages of important Australian Eastern Highland macrofloral sites. The Cambalong Creek site is late Paleocene (Selandian-Thanetian), with an age range of ∼ 57.3–59.8 Ma as inferred from palynostratigraphy (Proteacidites angulatus Subzone of the Lower Lygistepollenites balmei Zone). The Brandy Creek, Hotham Heights and Mount Buller sites are middle Eocene (Lutetian-Bartonian), with a minimum age of 39.58 ± 0.30 Ma, as inferred from 40Ar/39Ar analyses of overlying basalts, and a maximum age of ∼ 44 Ma inferred from palynostratigraphy (Lower Nothofagidites asperus Zone). The Kiandra Diggings site is early Miocene (Aquitanian), with a minimum age of 21.67 ± 0.26 Ma as inferred from 40Ar/39Ar dating and a maximum age of 23.03 Ma inferred from palynostratigraphy (Middle Proteacidites tuberculatus Zone). In the context of their revised ages, the recovered macrofloras suggest that subtropical climates prevailed during the late Paleocene (Cambalong Creek) and middle Eocene (Brandy Creek and Hotham Heights), whereas temperate climates existed during the early Miocene (Kiandra Diggings). For the middle Eocene sites, there is no discernible difference in paleotemperature estimates between lowland and highland sites, suggesting relatively low (< 550 m) paleoelevations for the present-day highland sites during the middle Eocene. This suggests that most of the present-day elevation (> 1400 m) was produced by post-middle Eocene uplift. • Ages of important Australian Eastern Highland macrofloral sites constrained. • Ages inferred through palynostratigraphy and 40Ar/39Ar analyses. • Subtropical climates in SE Australia during the late Paleocene and middle Eocene. • Similar temperature estimates for lowland and highland Eocene sites. • Present-day elevation (> 1400 m) produced by post-middle Eocene uplift. [ABSTRACT FROM AUTHOR]

Seismic characterization of Eocene-Oligocene heterozoan carbonate strata from the Browse Basin, Northwest Shelf of Australia, defines marked progradation of nearly 10 km. Stratal terminations and stacking subdivide the succession into mappable seismic units. Stratal architecture and seismic geomorphology varies systematically through the succession. Individual surfaces, discerned by toplap, onlap, and truncation, outline sigmoidal to tangential oblique clinoforms with heights of ranging from 350 to 650 m and maximum gradients between 8 and 18°. Sigmoidal clinoforms can include aggradation in excess of ∼200 m, prograde more than 500 m, and have slopes characterized by inclined, wavy to discontinuous reflectors that represent ubiquitous gullies and channels. In contrast, the overlying tangential oblique clinoforms include downstepped shelf margins, limited on-shelf aggradation (<100 m) and toplap, subdued progradation (<500 m), and continuous parallel inclined reflectors on the slope. Wedges of basinally restricted reflectors at toe of slope onlap surfaces of pronounced erosional truncation or syndepositional structural modification. The succession includes repeated patterns of seismic units that onlap, aggrade, and prograde, interpreted to represent sequence sets and composite sequences. The associations of shelf aggradation, shelf-margin progradation, and slope channeling within sigmoidal seismic units and the less marked progradation and channeling within tangential oblique seismic units contrast with the classic sequence model in which sediment delivery to the slope and pronounced progradation is favored by limited shelf accommodation. This distinct divergence is interpreted to reflect the prolific heterozoan production across the shelf during periods of rising and high base level when the shelf is flooded, perhaps enhanced by downwelling. Comparison with purely photozoan systems reveals similarities and contrasts in seismic stratigraphic heterogeneity and architecture, interpreted to be driven by distinct characteristics of heterozoan sedimentary systems. [ABSTRACT FROM AUTHOR]

The Eocene was a critical period of global plate reorganization and it also saw the Earth's climate transition from the warmhouse state to the coolhouse state. Reconstructing the Eocene sedimentary history in the climate-sensitive Southern Ocean is important for understanding paleoenvironmental changes in response to the accelerated Australia/Antarctica separation and global cooling throughout the middle and late Eocene. Here, we present the first detailed multiproxy record of a continuous sequence from International Ocean Discovery Program (IODP) Site U1514 in the Mentelle Basin off southwestern Australia. Our aim is to reconstruct the sediment provenances and paleoenvironmental evolution in response to the abovementioned climatic and tectonic changes in the mid-high southern latitudes during the Eocene. Provenance analyses based on Sr-Nd isotopes, trace elements, and clay mineral assemblages suggest that Eocene sediments at Site U1514 predominantly originated from the southwestern Australian continent and the Naturaliste Plateau. Sediment provenance variations during the middle Eocene indicate that the onset of fast separation between Australia and Antarctica at 43 Ma caused an increased supply of volcanic materials from the Naturaliste Plateau between 43 and 38 Ma. Terrigenous inputs to the Mentelle Basin during the middle Eocene were primarily controlled by paleoclimate changes rather than tectonic processes because coeval clay mineralogical changes (higher kaolinite/smectite ratio and MAR kaolinite) indicate a period of stronger physical erosion and chemical weathering on the western Australian continent that resulted in increased terrigenous materials delivered to the Mentelle Basin. Our results reveal a 5 Myr-long (43–38 Ma) warming reversal in the southern mid-high latitudes, providing an exception to the generally short-lived (10–100 kyr-long) hyperthermals that interrupted the long-term global cooling throughout the middle to late Eocene. As for the late Eocene (38–37 Ma), tectonic processes related to the sudden acceleration in seafloor spreading in the Tasman Sea led to the exposure of shallower areas, resulting in rapid detritus accumulation at the study site. During the late Eocene (37–34 Ma), major sediment provenance shifted from distal source areas (e.g., the Yilgarn Craton) to relatively proximal sources (e.g., the Leeuwin Block and Perth Basin). We interpret that the regional uplift in southwestern Australia and coeval climate cooling resulted in the diversion and inactivation of large drainage systems, thus blocking the transportation of sediment from distant regions. • First detailed record of the Eocene source-to-sink process in the Mentelle Basin. • The onset of fast Australia/Antarctica separation caused increased volcanic input. • Regional warming led to enhanced chemical weathering in Australia during 43–38 Ma. • Regional uplift and global cooling induced sediment source change during 37–34 Ma. [ABSTRACT FROM AUTHOR]

The occurrence and distribution of alkylphenanthrenes in upper Eocene–Oligocene sediments from Ocean Drilling Program Leg 189 (Sites 1168, 1170, 1171 and 1172) that were drilled off the coast of Tasmania have been examined by gas chromatography–mass spectrometry. Samples are thermally immature and contain predominantly terrigenous organic matter. Peculiar alkylphenanthrene distributions occur in four samples from Site 1168 at depths from 748 m to 762 m, with methylphenanthrene (MP) isomers showing complicated and irregular distributions. A dominance of 3-MP, 9-MP and 1-MP occurs in different samples, while 2-MP is systematically low in all the samples. Concentrations of alkylphenanthrenes and various other aromatic hydrocarbons generally increase with burial depth at Site 1168, likely indicating diagenetic formation. Commonly used source input and thermal maturity parameters derive inconsistent and confusing interpretations for all four sites. Maturity does not appear to be a decisive factor that influences the distributions of methylphenanthrene and dimethylphenanthrene (DMP) isomers and the degree of alkylation. The direct decomposition of retene to form an abnormal enrichment of 1-MP in one sample from Site 1168 is also difficult to envisage. The low 1,7-DMP/1,3- + 3,9- + 2,10- + 3,10-DMPs and ∑alkylphenanthrenes/∑alkylnaphthalenes ratios, coupled with the predominance of hopanoids over steroids, point to microbial input of 3-MP and 1-MP as a plausible interpretation in certain samples, while the dominance of 9-MP throughout the sedimentary column reflects local biomass input formed in the marine environment. Input of combustion-derived alkylphenanthrenes is unlikely to be the sole reason to cause unusually high phenanthrene/∑methylphenanthrenes ratios in the samples from the four sites. Oxidation during deposition and the immaturity of the sediments at an early diagenesis stage are likely to be an alternative interpretation. • Alkylphenanthrenes in immature sediments respond to source and environmental interactions. • Microbial interference can lead to unusual methylphenanthrene isomer distributions. • Maturity parameters from alkylphenanthrenes can be altered by microbial interference. • High P/ΣMP ratios (> 1.0) do not necessary reflect combustion/pyrogenic input. [ABSTRACT FROM AUTHOR]

The macrofossil record of monocotyledons for New Zealand and Australia is updated on the basis of recent finds. In particular, reports for mummified leaf fossils with good cuticular preservation reveal significant fossil age or range extensions for a number of families in several different orders, including Ripogonaceae in the Eocene of Tasmania and New Zealand (and South America), and calamoid and other Arecaceae from the Eocene of southern New Zealand. There are also earliest macrofossil records for several families or subfamilies, including Alstroemeriaceae: Luzuriagoideae ( Luzuriaga), Arecaceae, Asparagaceae: Lomandroideae ( Cordyline), Asteliaceae ( Astelia), Cymodoceaceae (aff. Ruppia), Cyperaceae, Restionaceae, Orchidaceae: Epidendroideae ( Dendrobium and Earina), Asphodelaceae (previously Xanthorrhoeaceae): Hemerocallidoideae ( Dianella/ Phormium) and Xeronemataceae ( Xeronema) from the Miocene of New Zealand. In addition, an Ensete-like seed associated with Pakawaua ( Musaceae) and a leaf fragment of a second Musaceae-like species of Miocene age are presented. The biogeographical and palaeoecological implications of these records, especially for tropical or subtropical taxa occurring at mid to high southern latitudes, is discussed. In particular, the role and ecology of the relatively high-diversity monocot fossils in the sclerophyllous swamp forest at Newvale Mine in Southland and the lake-edge rainforest at Foulden Maar are explored. © 2015 The Linnean Society of London, Botanical Journal of the Linnean Society, 2015, 178, 394-420. [ABSTRACT FROM AUTHOR]

I describe Archaeonothos henkgodthelpi gen. et. sp. nov., a small (estimated body mass ~40-80 g) tribosphenic metatherian from the early Eocene Tingamarra Fauna of southeastern Queensland, Australia. This taxon, known only from a single isolated upper molar (M2 or M3) is characterised by a very distinctive combination of dental features that, collectively, probably represent faunivorous adaptations. These include: a straight, elevated centrocrista; a metacone considerably taller than the paracone; a wide stylar shelf (~50% of the total labiolingual width of the tooth); reduced stylar cusps; a long postmetacrista; a small and anteroposteriorly narrow protocone; an unbasined trigon; and the absence of conules. Some of these features are seen in dasyuromorphians, but detailed comparisons reveal key differences between A. henkgodthelpi and all known members of this clade. A. henkgodthelpi also predates recent molecular estimates for the divergence of crown-group Dasyuromorphia. Similar dental features are seen in a number of other metatherians, including the South American sparassodonts, Wirunodon chanku from the ?middle--late Eocene Santa Rosa local fauna of Peru, and Kasserinotherium tunisiense from the early Eocene Chambi fauna of Tunisia, although whether A. henkgodthelpi is closely related to any of these taxa is unclear based on available evidence. I therefore refer A. henkgodthelpi to Metatheria incertae sedis. Potential relatives of A. henkgodthelpi are unknown from any other Australian fossil deposit. [ABSTRACT FROM AUTHOR]

* Premise of the study: Agathis is an iconic genus of large, ecologically important, and economically valuable conifers that range over lowland to upper montane rainforests from New Zealand to Sumatra. Exploitation of its timber and copal has greatly reduced the genus's numbers. The early fossil record of Agathis comes entirely from Australia, often presumed to be its area of origin. Agathis has no previous record from South America. * Methods: We describe abundant macrofossils of Agathis vegetative and reproductive organs, from early and middle Eocene rainforest paleofloras of Patagonia, Argentina. The leaves were formerly assigned to the New World cycad genus Zamia. * Key results: Agathis zamunerae sp. nov. is the first South American occurrence and the most complete representation of Agathis in the fossil record. Its morphological features are fully consistent with the living genus. The most similar living species is A. lenticula, endemic to lower montane rainforests of northern Borneo. * Conclusions: Agathis zamunerae sp. nov. demonstrates the presence of modern-aspect Agathis by 52.2 mya and vastly in creases the early range and possible areas of origin of the genus. The revision from Zamia breaks another link between the Eocene and living floras of South America. Agathis was a dominant, keystone element of the Patagonian Eocene floras, along side numerous other plant taxa that still associate with it in Australasia and Southeast Asia. Agathis extinction in South America was an integral part of the transformation of Patagonian biomes over millions of years, but the living species are disappearing from their ranges at a far greater rate. [ABSTRACT FROM AUTHOR]

A partial quadrate (essentially the otic part) from the nonmarine, earliest Eocene (54.6 Ma) Tingamarra Local Fauna in Queensland, Australia, has been identified as the oldest Australian anseriform fossil. The Tingamarra quadrate shows a combination of plesiomorphic anseriform characters with a unique synapomorphic character complex of the Anhimidae (screamers), which today are endemic to South America. In concert with the basal position of the Anhimidae among the crown-group anseriforms, this set of characters suggests a stem group of the Anhimidae, raising a possibility of the Transantarctic migration of stem anhimids to South America. The quadrate morphology supports palaeognathous rather than recently claimed anhimid relationships of the Dromornithidae and identifies Sylviornis as an anseriform rather than a galliform. [ABSTRACT FROM AUTHOR]

A previously undescribed tooth from the Muñani Formation at the Laguna Umayo locality, Peru, represents the new didolodontid Umayodus raimondi gen. et sp. nov., here diagnosed by the presence of a well developed metastylid and ectostylid, and a twinned hypoconulid. This taxon is closely related to the middle Paleocene genera Escribania and Raulvaccia from the locality of Punta Peligro in Patagonia, Argentina. Phylogenetic analysis here performed indicates that they constitute a monophyletic group within Didolodontidae, supported by five derived characters: the hypocone well developed and close to the protocone; the strongly concave precingulum; the contact between the postcristid and the entoconid; the contact of the crista pre-paraconular, precingulum and parastyle; and the mesiodistal enlargement of the m3 talonid. Their paleogeographic distribution fit with those of the actual Andean Region of the Austral Kingdom. The previously assumed Thanetian--Ypresian age assignment for the Laguna Umayo LU3 fauna is here reinforced by faunistic comparisons with the earliest Eocene Murgon fauna, in Australia, and the Itaboraian South American Land Mammal Age, represented from faunas of Patagonia, Argentina and São José de Itaboraí, Brazil. [ABSTRACT FROM AUTHOR]

Detrital zircons from the Eocene Garford paleovalley, central South Australia, were derived from two main sources: (i) local Archean-Mesoproterozoic rocks of the Gawler Craton exposed in the paleocatchment, including the 2525-2440 Ma Mulgathing Complex and 1595-1575 Ma Gawler Range Volcanics-Hiltaba Suite; and (ii) Phanerozoic sedimentary rocks in the catchment that contribute a Late Mesoproterozoic to Cretaceous component of recycled zircons from a variety of primary sources. These sources include: the 1190-1120 Ma Pitjantjatjara Supersuite and 1080-1040 Ma Giles Complex, in the Musgrave Province; ca 510 Ma syn-Delamerian magmatism possibly derived from the Adelaide Rift Complex; and Jurassic-Cretaceous zircons ranging from ca 220 Ma to ca 100 Ma, with a prominent population at 122 ± 3 Ma. It is likely that zircons from these sources outside the paleocatchment were transported into the Mesozoic rocks of the Eromanga Basin within the catchments, before being re-eroded into the Garford paleovalley. Given the presence of significant gold mineralisation in the Neoarchean rocks of the Gawler Craton, the abundance of locally derived Archean zircons suggests potential for paleoplacer gold deposits in the Eocene paleodrainage system. Likewise, the abundance of zircons derived from the Gawler Range Volcanics-Hiltaba Suite supports the potential for secondary uranium mineralisation in the paleovalleys derived from Mesoproterozoic volcanics and granites, some of which are known to be uranium-enriched. Finally, these data suggest that the Garford paleovalley was not a major contributor to the zircon budget of the heavy-mineral sands province of the adjacent Eucla Basin. [ABSTRACT FROM AUTHOR]

Abstract: Using palynostratigraphy combined with analysis of lithostratigraphy and sedimentary facies of discontinuous outcrops and selected drillholes, we have investigated whether the Eocene sequences and their boundaries in the Eucla Basin of South Australia were synchronous with major sea-level events. The correlation of Eocene sequences and their boundaries in the eastern nearshore and onshore Eucla Basin indicates that these complex marine–nonmarine strata fall into four sequences or allostratigraphic packages that can be seen from the offshore basin to nearshore and onshore basin, including palaeovalleys. Key sedimentary surfaces (disconformities, a tidal/wave ravinement surface, transgressive surfaces, maximum flooding surfaces) bound the packages (including three new revised units) and are coincident with four third-order sequence boundaries. The eastern Eucla Basin stratigraphy accords with the general view of Eocene sea-level patterns and elucidates a stepwise evolution of marine and nonmarine environments. [Copyright &y& Elsevier]

The spatial and temporal vegetation and environmental dynamics of an Eocene sequence from south-western Australia, based on pollen and geochemical analyses, is presented here. The vegetation was dominated by Nothofagus species with other gymnosperms such as Araucaria and Podocarpus intermixed with Myrtaceae, Proteaceae and Casuarinaceae. Pollen of Proteaceae were an important and consistent component of the vegetation; as much, or more so than at present. Results from this study show that the Proteaceous component is up to 42% of the total pollen counts. Removing data for the dominant Nothofagus taxon did not alter the apparent dominance of Proteaceae species, though the abundance and types of species changed. The abundance and diversity of the flora here supports the view that there are differences between the flora in eastern and western parts of Australia at this time. In addition, a main finding of this research is that there can be considerable spatial and temporal variability in the abundance and diversity of taxa, and specifically Proteaceous taxa, in landscapes in the Eocene. [Copyright &y& Elsevier]

The Eocene succession filling palaeovalleys in the northeastern Eucla Basin, South Australia, is interpreted using facies and sequence-stratigraphic models based on relative sea-level changes. The dominantly fluvial sediments were deposited in incised valleys which graded basinwards to an estuarine coastal plain under warm and humid palaeoclimatic conditions. Sedimentological examination suggests a tidal influence in this fluvial succession. Fluvial–estuarine-shoreline facies associations can be recognised in these (Eocene) sequences, each of which comprises a diverse assemblage of lithofacies that can be grouped into lowstand and/or transgressive and highstand system tracts. Since the palaeorivers had hydrological connection with the sea, deposition was dominantly controlled by sea-level changes. Results of the study indicate that two third-order Eocene eustatic cycles have largely controlled sedimentation. The resulting key surfaces (unconformity, and transgressive, tidal/wave ravinement, and maximum flooding surfaces) bound depositional sequences which extend over significant areas and may be used in basin-wide correlations of stratal packages. [Copyright &y& Elsevier]

A Late Eocene foraminiferal fauna of free specimens is recorded from Cascade Seamount, a feature of volcanic origin, whose age and fauna were previously studied only in thin-section. The fauna is of Late Eocene (P15) age because of the presence of Globigerapsis index, Globigerapsis rubriformis, Subbotina linaperta, Subbotina angiporoides and Chiloguembelina cubensis. Many typical Eocene indicators, such as Hantkenina, Pseudohastigerina and key globorotaliids, are absent. The age is a little older than that estimated for previous samples from the seamount. The fauna is dominated (78%) by benthic species, especially species of Cibicides that have greater affinities with New Zealand faunas than with coeval southern Australian faunas. The sediment and its fauna accumulated near the lower limits of wave activity, off the coast of a volcano that probably stood at least 400 m above sea-level. The location has subsided nearly 1000 m over the past 40 million years to its present water depth of ~1000 m, suggesting that the entire East Tasman Plateau was approximately 1000 m above its current depth at the time. Conditions were cool temperate and the fauna lacks any warm-water indices, consistent with a palaeolatitude of 55–60°S, but also with cool waters at a time of oscillating conditions in southern Australia and also in Antarctica. There is essentially no infauna and the waters were highly oxygenated in the turbulent zone. [ABSTRACT FROM AUTHOR]

The mid to outer neritic carbonates of the Gambier Limestone (Upper Eocene to lower Middle Miocene) can be divided into seven units by using criteria of sequence stratigraphy and foraminiferal biofacies. The boundaries fall mainly on erosional surfaces, even though the temporal duration of these surfaces appears to be largely beyond the resolution of foraminiferal biostratigraphy. The Eocene/Oligocene contact is distinctively unconformable in several sections, with at least part of the Upper Eocene sediments missing. Chert nodules, common to abundant in most sections, are associated with deep- or cool-water benthic assemblages (> 100–200 m and < 15°C), indicating cool, nutrient-rich bottom conditions probably influenced by the Antarctic Circumpolar Current beginning during the Early Oligocene. The mid-Oligocene fall in sea-level was probably coupled with a major local uplift that removed at least part of the Lower Oligocene, an event widely recorded in the Australian–New Zealand region. In areas weakly affected, this glacioeustatic lowstand is represented by chert-free limestone and grey to pink dolomites in some sections, with a poorly preserved assemblage comprising few planktonic and deep-water benthic species. Local unconformities separate regional unconformity-bounded or allostratigraphic packages of strata to represent third-order sequences. Although variations in local subsidence might have influenced accumulation space and sediment thickness, glacioeustatic influence on the packaging of the sequences and units of the Gambier Limestone was easily the more effective and concordant with the global patterns. [ABSTRACT FROM AUTHOR]

Late Eocene time in the Bremer and western Eucla Basins of southern Western Australia was a period of terrigenous clastic and abundant, unusual, biosiliceous sponge sedimentation. The Pallinup Formation (revised) consists of five units; 1 and 2 are basal sandstones, 3 and 4 are variably spiculitic mudstones, whilst the uppermost unit is spiculite and spongolite, and formalised as the Fitzgerald Member (new). The Pallinup Formation, plus coeval spiculites in palaeovalleys and carbonates in the western Eucla Basin, accumulated during one large-scale, transgressive–regressive relative sea-level cycle. Drowned, low-gradient rivers supplied mud but little sand. Instead, sand was locally sourced via transgressive shoreface erosion of deeply weathered regolith. Regression terminated shoreface erosion, eliminated the sand source, and resulted in a river-supplied, clay-dominated shallow-marine depositional system. The unit 2–3 sandstone–mudstone transition, which would normally be interpreted as transgressive drowning, is in this case the result of regressive cessation of sand supply. The peak relative sea-level (highstand) horizon thus lies within unit 2 sandstones, a facies that would usually be considered wholly transgressive, and no highstand systems tract was deposited. The maximum flooding and downlap surfaces are the same horizon and cap the transgressive systems tract. They formed coincidentally or subsequent to peak relative sea-level, but prior to initiation of unit 3 mudstone deposition. Upper unit 2 plus unit 3 represent a condensed section systems tract, and unit 4 plus the Fitzgerald Member comprise a regressive systems tract. [ABSTRACT FROM AUTHOR]

The Paleoproterozoic (1.7 Ga [billion years ago]) metasedimentary rocks of the Mount Barren Group in southwestern Australia contain burrows indistinguishable from ichnogenera Thalassinoides , Ophiomorpha , Teichichnus , and Taenidium , known from firmgrounds and softgrounds. The metamorphic fabric in the host rock is largely retained, and because the most resilient rocks in the sequence, the metaquartzites, are too hard for animal burrowing, the trace fossils have been interpreted as predating the last metamorphic event in the region. Since this event is dated at 1.2 Ga, this would bestow advanced animals an anomalously early age. We have studied the field relationships, petrographic fabric, and geochronology of the rocks and demonstrate that the burrowing took place during an Eocene transgression over a weathered regolith. At this time, the metaquartzites of the inundated surface had been weathered to friable sandstones or loose sands (arenized), allowing for animal burrowing. Subsequent to this event, there was a resilicification of the quartzites, filling the pore space with syntaxial quartz cement forming silcretes. Where the sand grains had not been dislocated during weathering, the metamorphic fabric was seemingly restored, and the rocks again assumed the appearance of hard metaquartzites impenetrable to animal burrowing., Competing Interests: The authors declare no competing interest.

Multiple stable isotope investigations from upper Eocene to lower Oligocene deep-water marine sequences record the transition from global greenhouse to the icehouse conditions (Oi-1 glacial). While Southern Ocean high latitude deep sea records of this transition are well known, their shallow marine equivalents are rare and have the potential to record the eustatic and oceanic consequences of Paleogene glacial variability. The well-known high paleolatitude (~55°S) neritic carbonate sequence at Browns Creek and Castle Cove in the Otway Basin in southeast Australia spans the Eocene-Oligocene boundary. During this time the area lay on the northeastern margin of the Australo-Antarctic Gulf facing the evolving Southern Ocean. The importance of this record has been hampered by a lack of a consistent stratigraphy and contradictory microfossil interpretations. To reconcile these issues we combine new bio-, chemo- and lithostratigraphic analyses of the outcrops and a new core (Colac-2) with pre-existing data to revise the stratigraphy. This confirms the middle/upper Eocene boundary is near the base of the section. The overlying upper Eocene siliciclastic strata are truncated by an unconformity (of ~0.8 Ma in duration) and overlain by glauconitic sand (the Notrostrea greensand) deposited after ~35.9 Ma. Subsequently deepening to middle to outer neritic depths deposited cyclic carbonates. Shallowing after ~35 Ma deposited laterally variable calcareous siliciclastic facies. These strata were tilted and eroded prior to 34 Ma leading to shallow water facies that may have been subaerially exposed during uplift. Brachiopod strontium isotope dates and an 0.5‰ carbon isotope excursion above this unconformity suggests the top of the Browns Creek and the base of the Castle Cove section correlate to Eocene-Oligocene transition (EOT-1) at ~34 Ma. The subsequent persistence of positive C/O isotope values above this level records the transition to the Oi-1 glaciation at ~33.7 Ma. Strong cyclicity in the inner shelf Castle Cove limestone is interpreted to record the commencement of obliquity dominated glacio-eustacy during the Oi-1 glacial phase. The shallowing from outer to inner shelf palaeodepths from the late Eocene to the early Oligocene is likely related to the onset of cryosphere expansion, however, palaeodepth estimates are complicated by the onset of regional compressional tectonism at the Eocene/Oligocene boundary that caused localized tilting and an unconformity with possible antisiphoning effects in this near-field site. • High paleolatitude records of Oi-1are rare and usually identified in deep sea sediments. • We describe a shelfal record of the Eocene-Oligocene Transition in south Australia. • The sequence records strong evidence for 41kyr obliquity during the Oi-1 glaciation. • A 41kyr obliquity driver for Oi-1 has previous been demonstrated only in isotope data. [ABSTRACT FROM AUTHOR]

• 16-million-year long history of Eocene sedimentation from the Mentelle Basin. • Astronomically paced variations in deep-sea sedimentation. • Astrochronology from the PETM (∼56 Ma) into the middle Eocene (∼40 Ma). • Contribution towards an Astronomical Time Scale for the entire Cenozoic. The geologic time scale for the Cenozoic Era has been notably improved over the last decades by virtue of integrated stratigraphy, combining high-resolution astrochronologies, biostratigraphy and magnetostratigraphy with high-precision radioisotopic dates. However, the middle Eocene remains a weak link. The so-called "Eocene time scale gap" reflects the scarcity of suitable study sections with clear astronomically-forced variations in carbonate content, primarily because large parts of the oceans were starved of carbonate during the Eocene greenhouse. International Ocean Discovery Program (IODP) Expedition 369 cored a carbonate-rich sedimentary sequence of Eocene age in the Mentelle Basin (Site U1514, offshore southwest Australia). The sequence consists of nannofossil chalk and exhibits rhythmic clay content variability. Here, we show that IODP Site U1514 allows for the extraction of an astronomical signal and the construction of an Eocene astrochronology, using 3-cm resolution X-Ray fluorescence (XRF) core scans. The XRF-derived ratio between calcium and iron content (Ca/Fe) tracks the lithologic variability and serves as the basis for our U1514 astrochronology. We present a 16 million-year-long (40-56 Ma) nearly continuous history of Eocene sedimentation with variations paced by eccentricity and obliquity. We supplement the high-resolution XRF data with low-resolution bulk carbon and oxygen isotopes, recording the long-term cooling trend from the Paleocene-Eocene Thermal Maximum (PETM – ca. 56 Ma) into the middle Eocene (ca. 40 Ma). Our early Eocene astrochronology corroborates existing chronologies based on deep-sea sites and Italian land sections. For the middle Eocene, the sedimentological record at U1514 provides a single-site geochemical backbone and thus offers a further step towards a fully integrated Cenozoic geologic time scale at orbital resolution. [ABSTRACT FROM AUTHOR]

Premise: Solanaceae is a scientifically and economically important angiosperm family with a minimal fossil record and an intriguing early evolutionary history. Here, we report a newly discovered fossil lantern fruit with a suite of features characteristic of Physalideae within Solanaceae. The fossil comes from the early Eocene Laguna del Hunco site (ca. 52 Ma) in Chubut, Argentina, which previously yielded the only other physaloid fruit fossil, Physalis infinemundi., Methods: The fruit morphology and calyx venation pattern of the new fossil were compared with P. infinemundi and extant species of Solanaceae., Results: Physalis hunickenii sp. nov. is clearly distinct from P. infinemundi in its fruiting calyx with wider primary veins, longer and thinner lobes, and especially in its venation pattern with high density, transverse tertiary veins; these features support its placement in a new species. In comparison with extant physaloid genera, the calyx venation pattern and other diagnostic traits reinforce placement of the new fossil, like P. infinemundi, within the tribe Physalideae of Solanaceae., Conclusions: Both species of fossil nightshades from Laguna del Hunco represent crown-group Solanaceae but are older than all prior age estimates of the family. Although at least 20 transoceanic dispersals have been proposed as the driver of range expansion of Solanaceae, the Patagonian fossils push back the diversification of the family to Gondwanan times. Thus, overland dispersal across Gondwana is now a likely scenario for at least some biogeographic patterns, in light of the ancient trans-Antarctic land connections between South America and Australia., (© 2020 Botanical Society of America.)

Middle to Upper Eocene carbonates recovered at ODP Leg 182 sites from the Great Australian Bight comprise three packages: (i) a 43–40 Ma quartzose limestone and packstone package; (ii) a 39–37 Ma wackestone package with ooze; and (iii) an Upper Eocene fine-grained wackestone package mainly 36.5–35 Ma in age. Bounding these sediment packages are unconformities inferred to have occurred at ca 43, ca 39, ca 37 and ca 34 Ma, coinciding with four major third-order sequence boundaries. Rapid changes in sea-floor spreading probably caused these unconformities, while a stable high sea-level between spreading pulses led to sediment packaging from offshore to coastal basins. The regional sea-level changes in these Middle to Late Eocene times, when glacioeustatic influence was minimal, were mainly driven by plate tectonics. Biofacies indicate a rapid subsidence, faster offshore than nearshore, during the first phase of accelerated sea-floor spreading between Australia and Antarctica around 43 Ma. Most significant environmental changes affecting sedimentation along the southern Australian margin at that time were the influx of warm waters from the Indian Ocean and the initial development of a stratified water mass in the deepening and widening Australo-Antarctic Gulf. The warm (surface) water supported plankton from the subtropics and migratory and endemic larger benthos including foraminifers, while the fertile deeper waters were sites of chert accumulation. The bloom of carbonate-generating bryozoans contributed to widespread carbonate sedimentation that progressed towards the southeastern margin ∼4 million years later. Subsequent carbonate packaging and unconformities, reflecting a stepwise accelerated sea-floor spreading pattern, persisted into the terminal Eocene before the onset of global glaciation. [ABSTRACT FROM AUTHOR]