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1
Evans, Scott D., Ian V. Hughes, James G. Gehling e Mary L. Droser. "Discovery of the oldest bilaterian from the Ediacaran of South Australia". Proceedings of the National Academy of Sciences 117, n. 14 (23 marzo 2020): 7845–50. http://dx.doi.org/10.1073/pnas.2001045117.
Testo completoAbstract (sommario):
Analysis of modern animals and Ediacaran trace fossils predicts that the oldest bilaterians were simple and small. Such organisms would be difficult to recognize in the fossil record, but should have been part of the Ediacara Biota, the earliest preserved macroscopic, complex animal communities. Here, we describeIkaria wariootiagen. et sp. nov. from the Ediacara Member, South Australia, a small, simple organism with anterior/posterior differentiation. We find that the size and morphology ofIkariamatch predictions for the progenitor of the trace fossilHelminthoidichnites—indicative of mobility and sediment displacement. In the Ediacara Member,Helminthoidichnitesoccurs stratigraphically below classic Ediacara body fossils. Together, these suggest thatIkariarepresents one of the oldest total group bilaterians identified from South Australia, with little deviation from the characters predicted for their last common ancestor. Further, these trace fossils persist into the Phanerozoic, providing a critical link between Ediacaran and Cambrian animals.
2
Sappenfield, Aaron, Mary L. Droser e James G. Gehling. "Problematica, trace fossils, and tubes within the Ediacara Member (South Australia): redefining the ediacaran trace fossil record one tube at a time". Journal of Paleontology 85, n. 2 (marzo 2011): 256–65. http://dx.doi.org/10.1666/10-068.1.
Testo completoAbstract (sommario):
Ediacaran trace fossils are becoming an increasingly less common component of the total Precambrian fossil record as structures previously interpreted as trace fossils are reinterpreted as body fossils by utilizing qualitative criteria. Two morphotypes, Form E and Form F of Glaessner (1969), interpreted as trace fossils from the Ediacara Member of the Rawnsley Quartzite in South Australia are shown here to be body fossils of a single, previously unidentified tubular constructional morphology formally described herein as Somatohelix sinuosus n. gen. n. sp. S. sinuosus is 2-7 mm wide and 3-14 cm long and is preserved as sinusoidal casts and molds on the base of beds. Well-preserved examples of this fossil preserve distinct body fossil traits such as folding, current alignment, and potential attachment to holdfasts. Nearly 200 specimens of this fossil have been documented from reconstructed bedding surfaces within the Ediacara Member. When viewed in isolated hand sample, many of these specimens resemble ichnofossils. However, the ability to view large quantities of reassembled and successive bedding surfaces within specific outcrops of the Ediacara Member provides a new perspective, revealing that isolated specimens of rectilinear grooves on bed bases are not trace fossils but are poorly preserved specimens of S. sinuosus. Variation in the quality and style of preservation of S. sinuosus on a single surface and the few distinct characteristics preserved within this relatively indistinct fossil also provides the necessary data required to define a taphonomic gradient for this fossil. Armed with this information, structures which have been problematic in the past can now be confidently identified as S. sinuosus based on morphological criteria. This suggests that the original organism that produced this fossil was a widespread and abundant component of the Ediacaran ecosystem.
3
Kakuwa, Yoshitaka, e James D. Floyd. "Trace fossils in Ordovician radiolarian chert successions in the Southern Uplands, Scotland". Earth and Environmental Science Transactions of the Royal Society of Edinburgh 107, n. 1 (marzo 2016): 13–22. http://dx.doi.org/10.1017/s1755691017000044.
Testo completoAbstract (sommario):
ABSTRACTRadiolarian chert and associated siliceous claystone in the Southern Uplands of Scotland are examined, in order to study the Great Ordovician Biodiversification Event of benthic animals on the pelagic ocean bottom. Trace fossils which are uncommon, but convincing, are found in the grey chert and siliceous claystone of Gripps Cleuch. These observations constitute firm evidence that large benthic animals which could leave visible trace fossils had colonised the Iapetan Ocean by the late Middle Ordovician, confirming previous studies from Australia for Panthalassa, the other huge ocean. Red chert is, however, a poor recorder of trace fossils, probably because the highly oxidising environment breaks down organic matter, both inhibiting high-density activity of large benthic animals and removing clear traces of benthic animal life.
4
Bell, Phil R., Russell D. C. Bicknell e Elizabeth T. Smith. "Crayfish bio-gastroliths from eastern Australia and the middle Cretaceous distribution of Parastacidae". Geological Magazine 157, n. 7 (30 ottobre 2019): 1023–30. http://dx.doi.org/10.1017/s0016756819001092.
Testo completoAbstract (sommario):
AbstractFossil crayfish are typically rare, worldwide. In Australia, the strictly Southern Hemisphere clade Parastacidae, while ubiquitous in modern freshwater systems, is known only from sparse fossil occurrences from the Aptian–Albian of Victoria. We expand this record to the Cenomanian of northern New South Wales, where opalized bio-gastroliths (temporary calcium storage bodies found in the foregut of pre-moult crayfish) form a significant proportion of the fauna of the Griman Creek Formation. Crayfish bio-gastroliths are exceedingly rare in the fossil record but here form a remarkable supplementary record for crayfish, whose body and trace fossils are otherwise unknown from the Griman Creek Formation. The new specimens indicate that parastacid crayfish were widespread in eastern Australia by middle Cretaceous time, occupying a variety of freshwater ecosystems from the Australian–Antarctic rift valley in the south, to the near-coastal floodplains surrounding the epeiric Eromanga Sea further to the north.
5
Trewin, N. H., e K. J. McNamara. "Arthropods invade the land: trace fossils and palaeoenvironments of the Tumblagooda Sandstone (?late Silurian) of Kalbarri, Western Australia". Transactions of the Royal Society of Edinburgh: Earth Sciences 85, n. 3 (1994): 177–210. http://dx.doi.org/10.1017/s026359330000359x.
Testo completoAbstract (sommario):
AbstractThe trace fossils of the Tumblagooda Sandstone (?late Silurian) of Kalbarri, Western Australia are spectacular in their variety and preservation. They provide a unique insight into the activities of the early invaders of terrestrial environments, and reveal the presence of a diverse fauna dominated by arthropods. Within the Formation trace fossil assemblages can be related to fluvial, aeolian and marine sand-dominated environments. Two distinct and diverse ichnofaunas are recognised.The Heimdallia–Diplichnites Ichnofauna occurs in sandstones deposited in broad low sinuosity braided fluvial channels, between which were mixed aeolian and waterlain sandsheets, small aeolian dunes and flooded interdune and deflation hollows. Heimdallia is the major bioturbator, favouring shallow pools. Other burrows include Tumblagoodichnus (gen. nov.), Diplocraterion, Skolithos, Beaconites and Didymaulyponomos. Arthropod trackways (Diplichnites) occur on surfaces of waterlain sands and on foreset bedding of aeolian dunes, and represent some of the earliest reported terrestrial trackways. Other trackways include Paleohelcura and Protichnites, and the digging traces Selenichnites and Rusophycus are also present. At least ten types of arthropods are required to produce the observed traces. Myriapods, eurypterids, euthycarcinoids, xiphosurids and scorpionids are considered responsible for the trackway assemblage.The Skolithos–Diplocraterion Ichnofauna occurs at the top of the exposed section in sandstones that overlie a thick fluvial sequence containing few traces. The strata are considered to represent marine influence at a fluvial/marine transition. They show variable trough cross-bedding, complex planar cross-bedding with down-climbing sets, ripple lamination, and fining-up sequences with bioturbated tops. Traces are dominated by crowded Skolithos up to 1 m long, together with two forms of Diplocraterion. Daedalus and Lunatubichnus (gen. nov.) burrows occur in a few beds and Aulichnites trails cover some foreset surfaces of cross-bedding.The trace fossils and the sedimentology of the Tumblagooda Sandstone bear a remarkable similarity to those of the lower part of the Taylor Group of Antarctica, which is probably Devonian in age. It is suggested that the two represent a similar age, stratigraphy, and range of environments on the margins of Gondwana. Large unvegetated fluvial outwash plains with variable aeolian influence were essentially coastal in character and fluvial/marine transitions occur in sand-rich environments. The animals responsible for the traces inhabited coastal areas but many could survive outwith marine influence, and arthropods responsible for some types of Diplichnites trackways walked out of water.The rich diversity of trackways attributable to arthropods illustrate that the invasion of terrestrial environments by arthropods, particularly large forms, was well-established by the beginning of the Devonian. The basis of the food chain was algal and bacterial films which bound the surface sediment in freshwater pools.
6
Camens, Aaron B., Stephen P. Carey e Lee J. Arnold. "Vertebrate Trace Fossils from the Late Pleistocene of Kangaroo Island, South Australia". Ichnos 25, n. 2-3 (11 luglio 2017): 232–51. http://dx.doi.org/10.1080/10420940.2017.1337633.
Testo completo
7
Schroeder, Natalie I., John R. Paterson e Glenn A. Brock. "Eldonioids with associated trace fossils from the lower Cambrian Emu Bay Shale Konservat-Lagerstätte of South Australia". Journal of Paleontology 92, n. 1 (gennaio 2018): 80–86. http://dx.doi.org/10.1017/jpa.2018.6.
Testo completoAbstract (sommario):
AbstractRare specimens of eldonioids recovered from the lower Cambrian (Series 2, Stage 4) Emu Bay Shale (EBS) Konservat-Lagerstätte represent the first record of the group for the Cambrian of East Gondwana. The disc-shaped body of the EBS taxon bears fine concentric corrugations on the dorsal surface and, ventrally, a series of internal lobes that have primary and secondary bifurcations, as well as a coiled sac. It appears to be most similar toRotadiscusandPararotadiscusof the Cambrian Chengjiang and Kaili biotas of South China, respectively. While the structure of the internal lobes would indicate that this occurrence in the EBS represents a new taxon within the Rotadiscidae, lack of detail regarding the precise number of internal lobes and the condition of the circumoral tentacles warrants a more conservative approach in leaving the genus and species under open nomenclature. The EBS specimens also host trace fossils, including the remains of a burrow, which are generally lacking in the body-fossil-bearing layers of the Konservat-Lagerstätte interval. These traces appear to have been made by small organisms and are similar to traces associated with the discs ofPararotadiscus guizhouensis(Zhao and Zhu, 1994) from the Kaili Biota. The available taphonomic, paleoenvironmental, and ichnological evidence indicates that the EBS eldonioids are most likely vagrants that were transported or settled into the ‘preservational trap’ and subsequently exposed on the substrate for a brief period before burial, thereby allowing organisms to exploit their carcasses for nutrients or other purposes.
8
Kakuwa, Y., e J. Webb. "Evolution of Cambrian to Ordovician trace fossils in pelagic deep-sea chert, Australia". Australian Journal of Earth Sciences 57, n. 5 (luglio 2010): 615–25. http://dx.doi.org/10.1080/08120099.2010.494766.
Testo completo
9
Shi, G. R., Yi-Ming Gong e A. Potter. "Late Silurian trace fossils from the Melbourne Formation, Studley Park, Victoria, southeastern Australia". Alcheringa: An Australasian Journal of Palaeontology 33, n. 3 (settembre 2009): 185–209. http://dx.doi.org/10.1080/03115510902844301.
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10
Bengtson, Stefan, Birger Rasmussen, Jian-Wei Zi, Ian R. Fletcher, James G. Gehling e Bruce Runnegar. "Eocene animal trace fossils in 1.7-billion-year-old metaquartzites". Proceedings of the National Academy of Sciences 118, n. 40 (27 settembre 2021): e2105707118. http://dx.doi.org/10.1073/pnas.2105707118.
Testo completoAbstract (sommario):
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.
11
Gangidine, Andrew, Malcolm R. Walter, Jeff R. Havig, Clive Jones, Daniel M. Sturmer e Andrew D. Czaja. "Trace Element Concentrations Associated with Mid-Paleozoic Microfossils as Biosignatures to Aid in the Search for Life". Life 11, n. 2 (13 febbraio 2021): 142. http://dx.doi.org/10.3390/life11020142.
Testo completoAbstract (sommario):
Identifying microbial fossils in the rock record is a difficult task because they are often simple in morphology and can be mimicked by non-biological structures. Biosignatures are essential for identifying putative fossils as being definitively biological in origin, but are often lacking due to geologic effects which can obscure or erase such signs. As such, there is a need for robust biosignature identification techniques. Here we show new evidence for the application of trace elements as biosignatures in microfossils. We found elevated concentrations of magnesium, aluminum, manganese, iron, and strontium colocalized with carbon and sulfur in microfossils from Drummond Basin, a mid-Paleozoic hot spring deposit in Australia. Our results also suggest that trace element sequestrations from modern hot spring deposits persist through substantial host rock alteration. Because some of the oldest fossils on Earth are found in hot spring deposits and ancient hot spring deposits are also thought to occur on Mars, this biosignature technique may be utilized as a valuable tool to aid in the search for extraterrestrial life.
12
Walter, M. R., R. Elphinstone e G. R. Heys. "Proterozoic and Early Cambrian trace fossils from the Amadeus and Georgina Basins, central Australia". Alcheringa: An Australasian Journal of Palaeontology 13, n. 3 (gennaio 1989): 209–56. http://dx.doi.org/10.1080/03115518908527821.
Testo completo
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Camens, Aaron Bruce, e Stephen Paul Carey. "Contemporaneous Trace and Body Fossils from a Late Pleistocene Lakebed in Victoria, Australia, Allow Assessment of Bias in the Fossil Record". PLoS ONE 8, n. 1 (2 gennaio 2013): e52957. http://dx.doi.org/10.1371/journal.pone.0052957.
Testo completo
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McMahon, William J., Alexander G. Liu, Benjamin H. Tindal e Maarten G. Kleinhans. "Ediacaran life close to land: Coastal and shoreface habitats of the Ediacaran macrobiota, the Central Flinders Ranges, South Australia". Journal of Sedimentary Research 90, n. 11 (30 novembre 2020): 1463–99. http://dx.doi.org/10.2110/jsr.2020.029.
Testo completoAbstract (sommario):
ABSTRACT The Rawnsley Quartzite of South Australia hosts some of the world's most diverse Ediacaran macrofossil assemblages, with many of the constituent taxa interpreted as early representatives of metazoan clades. Globally, a link has been recognized between the taxonomic composition of individual Ediacaran bedding-plane assemblages and specific sedimentary facies. Thorough characterization of fossil-bearing facies is thus of fundamental importance for reconstructing the precise environments and ecosystems in which early animals thrived and radiated, and distinguishing between environmental and evolutionary controls on taxon distribution. This study refines the paleoenvironmental interpretations of the Rawnsley Quartzite (Ediacara Member and upper Rawnsley Quartzite). Our analysis suggests that previously inferred water depths for fossil-bearing facies are overestimations. In the central regions of the outcrop belt, rather than shelf and submarine canyon environments below maximum (storm-weather) wave base, and offshore environments between effective (fair-weather) and maximum wave base, the succession is interpreted to reflect the vertical superposition and lateral juxtaposition of unfossiliferous non-marine environments with fossil-bearing coastal and shoreface settings. Facies comprise: 1, 2) amalgamated channelized and cross-bedded sandstone (major and minor tidally influenced river and estuarine channels, respectively), 3) ripple cross-laminated heterolithic sandstone (intertidal mixed-flat), 4) silty-sandstone (possible lagoon), 5) planar-stratified sandstone (lower shoreface), 6) oscillation-ripple facies (middle shoreface), 7) multi-directed trough- and planar-cross-stratified sandstone (upper shoreface), 8) ripple cross-laminated, planar-stratified rippled sandstone (foreshore), 9) adhered sandstone (backshore), and 10) planar-stratified and cross-stratified sandstone with ripple cross-lamination (distributary channels). Surface trace fossils in the foreshore facies represent the earliest known evidence of mobile organisms in intermittently emergent environments. All facies containing fossils of the Ediacaran macrobiota remain definitively marine. Our revised shoreface and coastal framework creates greater overlap between this classic “White Sea” biotic assemblage and those of younger, relatively depauperate “Nama”-type biotic assemblages located in Namibia. Such overlap lends support to the possibility that the apparent biotic turnover between these assemblages may reflect a genuine evolutionary signal, rather than the environmental exclusion of particular taxa.
15
Jago, J. B., e C. G. Gatehouse. "Early Cambrian trace fossils from the Kanmantoo Group at Red Creek, South Australia, and their stratigraphic significance". Australian Journal of Earth Sciences 54, n. 4 (giugno 2007): 531–40. http://dx.doi.org/10.1080/08120090601078370.
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Retallack, Gregory J. "Ordovician Life on Land and Early Paleozoic Global Change". Paleontological Society Papers 6 (novembre 2000): 21–46. http://dx.doi.org/10.1017/s1089332600000693.
Testo completoAbstract (sommario):
Many Paleontologists share the opinion of McGhee (1996), who wrote “Prior to the Devonian, there was no terrestrial ecosystem to speak of. Some primitive plants precariously establishing a beachhead in protected coastal areas was about it. The interiors of the continents of the planet Earth were as barren as the rocky landscapes of Mars.” Thus, it was with trepidation that I reported paleosols containing trace fossils of early land animals in the late Ordovician, Juniata Formation, of Pennsylvania (Retallack and Feakes, 1987; Retallack, 1992a, 1992b, 1993). My late colleague, Jane Gray, engendered considerable debate by reporting Ordovician and Early Silurian spores like those of liverworts (Gray and Boucot, 1977; Gray, 1985). This spore, trace fossil and paleosol evidence for life on land in the Ordovician has remained controversial (Buatois et al., 1998; Shear, 1998), but evidence for Ordovician life on land has continued to accumulate. Especially important was discovery of myriapod trackways from mid-Ordovician (Llandeilian-Caradocian) Borrowdale Volcanics of the Lake District, England (Johnson et al., 1994). Abundant arthropod burrows and tracks, and a single body fossil of an euthycarcinoid in the fluvial-eolian Tumblagooda Sandstone of Western Australia (White 1990; McNamara and Trewin, 1993; Trewin and McNamara, 1995) are now thought to be late Ordovician in age (Iaksy et al., 1998). An enigmatic assemblage of arthropods and plants from a mid-Ordovician paleokarst in Tennessee (Caster and Brooks, 1956) is now thought to have been lacustrine (Gray, 1988a). The fossil record of Ordovician land plants also has improved with the discovery of possible megafossil mosses (Snigirevskaya et al. 1992), and possible late Ordovician trilete spores (Nøhr-Hansen and Koppelhus, 1998; Richardson 1988; Strother, 1991; Strother et al., 1996). But the most abundant evidence for Ordovician life on land remains fossil soils, now exploited by increasingly thorough and sophisticated studies (Retallack, 1985, 1992a, 1992b, 1993; Feakes et al., 1989; Driese and Foreman 1991, 1992a, 1992b; Driese et al., 1992, 1997; Mora et al., 1991, 1996; Mora and Driese, 1993; Yapp and Poths, 1992, 1994, 1996; Yapp, 1993, 1996). Mounting evidence from fossils and paleosols now presents an increasingly detailed view of Ordovician ecosystems on land.
17
Schroeder, Natalie I., John R. Paterson e Glenn A. Brock. "RETRACTION—Eldonioids with associated trace fossils from the lower Cambrian Emu Bay Shale Konservat-Lagerstätte of South Australia". Journal of Paleontology 92, n. 1 (gennaio 2018): 114. http://dx.doi.org/10.1017/jpa.2017.156.
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Gouramanis, Chris, e Stephen McLoughlin. "Siluro-Devonian trace fossils from the Mereenie Sandstone, Kings Canyon, Watarrka National Park, Amadeus Basin, Northern Territory, Australia". Alcheringa: An Australasian Journal of Palaeontology 40, n. 1 (2 gennaio 2016): 118–28. http://dx.doi.org/10.1080/03115518.2016.1099957.
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Jensen, Sören, Anette E. S. Högström, Magne Høyberget, Guido Meinhold, Duncan McIlroy, Jan Ove R. Ebbestad, Wendy L. Taylor, Heda Agić e Teodoro Palacios. "New occurrences of Palaeopascichnus from the Stáhpogieddi Formation, Arctic Norway, and their bearing on the age of the Varanger Ice Age". Canadian Journal of Earth Sciences 55, n. 11 (novembre 2018): 1253–61. http://dx.doi.org/10.1139/cjes-2018-0035.
Testo completoAbstract (sommario):
We report on new occurrences of the late Ediacaran problematicum Palaeopascichnus (Protista?) from the Stáhpogieddi Formation, Arctic Norway. The stratigraphically lowest occurrences are in beds transitional between the Lillevannet and Indreelva members: the highest in the second cycle of the Manndrapselva Member, stratigraphically close to the lowest occurrences of Cambrian-type trace fossils. This establishes a long stratigraphical range of Palaeopascichnus on the Digermulen Peninsula, as has been previously documented from Newfoundland, South Australia, and elsewhere in Baltica. The age range of Palaeopascichnus in Avalonia and Baltica is from ∼565 to 541 Ma. Since the transition from the Mortensnes Formation to the Stáhpogieddi Formation is without a major break in sedimentation, this supports the inference that the underlying glacigenic Mortensnes Formation is ca. 580 Ma, and therefore Gaskiers-equivalent, or younger.
20
Shillito, Anthony P., e Neil S. Davies. "The Tumblagooda Sandstone revisited: exceptionally abundant trace fossils and geological outcrop provide a window onto Palaeozoic littoral habitats before invertebrate terrestrialization". Geological Magazine 157, n. 12 (13 aprile 2020): 1939–70. http://dx.doi.org/10.1017/s0016756820000199.
Testo completoAbstract (sommario):
AbstractThe establishment of permanent animal communities on land was a defining event in the history of evolution, and one for which the ichnofauna and facies of the Tumblagooda Sandstone of Western Australia have been considered an archetypal case study. However, terrestrialization can only be understood from the rock record with conclusive sedimentological evidence for non-marine deposition, and original fieldwork on the formation shows that a marine influence was pervasive throughout all trace fossil-bearing strata. Four distinct facies associations are described, deposited in fluvial, tidal and estuarine settings. Here we explain the controversies surrounding the age and depositional environment of the Tumblagooda Sandstone, many of which have arisen due to the challenges in distinguishing marine from non-marine depositional settings in lower Palaeozoic successions. We clarify the terminological inconsistency that has hindered such determination, and demonstrate how palaeoenvironmental explanations can be expanded out from unambiguously indicative sedimentary structures. The Tumblagooda Sandstone provides a unique insight into an early Palaeozoic ichnofauna that was strongly partitioned by patchy resource distribution in a littoral setting. The influence of outcrop style and quality is accounted for to contextualize this ichnofauna, revealing six distinct low-disparity groups of trace fossil associations, each related to a different sub-environment within the high-ichnodisparity broad depositional setting. The formation is compared with contemporaneous ichnofaunas to examine its continued significance to understanding the terrestrialization process. Despite not recording permanent non-marine communities, the Tumblagooda Sandstone provides a detailed picture of the realm left behind by the first invertebrate pioneers of terrestrialization.
21
McIlroy, D. "WEBBY B. D., MÁNGANO M. G. & BUATOIS L. A. (eds) 2004. Trace Fossils in Evolutionary Palaeoecology. Proceedings of Session 18 (Trace Fossils) of the First International Palaeontological Congress Sydney, Australia, July 2002. Fossils and Strata no. 51. v + 153 pp. Oslo: Taylor & Francis. Price US $50.00 (paperback). ISSN 0300-9491". Geological Magazine 144, n. 3 (maggio 2007): 605. http://dx.doi.org/10.1017/s0016756806002846.
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Cruse, T., L. B. Harris e B. Rasmussen. "Geological note: The discovery of Ediacaran trace and body fossils in the Stirling Range Formation, Western Australia: Implications for sedimentation and deformation during the ‘Pan‐African’ orogenic cycle". Australian Journal of Earth Sciences 40, n. 3 (giugno 1993): 293–96. http://dx.doi.org/10.1080/08120099308728081.
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Gehling, James G., Bruce N. Runnegar e Mary L. Droser. "Scratch Traces of Large Ediacara Bilaterian Animals". Journal of Paleontology 88, n. 2 (marzo 2014): 284–98. http://dx.doi.org/10.1666/13-054.
Testo completoAbstract (sommario):
Ediacara fan-shaped sets of paired scratchesKimberichnus teruzziifrom the Ediacara Member of the Rawnsley Quartzite, South Australia, and the White Sea region of Russia, represent the earliest known evidence in the fossil record of feeding traces associated with the responsible bilaterian organism. These feeding patterns exclude arthropod makers and point to the systematic feeding excavation of seafloor microbial mats by large bilaterians of molluscan grade. Since the scratch traces were made into microbial mats, animals could crawl over previous traces without disturbing them. The trace maker is identified asKimberella quadrata, whose death masks co-occur with the mat excavation traces in both Russia and South Australia. The co-occurrence of animals and their systematic feeding traces in the record of the Ediacara biota supports previous trace fossil evidence that bilaterians existed globally before the Cambrian explosion of life in the ocean.
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Farman, Roy M., e Phil R. Bell. "Australia's earliest tetrapod swimming traces from the Hawkesbury Sandstone (Middle Triassic) of the Sydney Basin". Journal of Paleontology 94, n. 5 (7 maggio 2020): 966–78. http://dx.doi.org/10.1017/jpa.2020.22.
Testo completoAbstract (sommario):
AbstractThe Hawkesbury Sandstone (Hawkesbury Series, Sydney Basin) on the southeastern coast of New South Wales, Australia, preserves a depauperate but important vertebrate tetrapod body-fossil record from the Early and Middle Triassic. As with many fossil sites around the world, the ichnological record has helped to shed light on the paleoecology of this interval. Herein, we investigate historical reports of a trackway pertaining to a putative short-tailed reptile found at Berowra Creek in the 1940s. Reinvestigation of the surviving track-bearing slabs augmented by archival photographs of the complete trackway, suggests that these impressions, which consist primarily of didactyl tracks (plus less common monodactyl and tridactyl traces), represent the earliest example of a swimming tetrapod found in Australia. Another isolated specimen (possibly from a nearby locality at Annangrove) appears to represent similar didactyl swim traces of a second, larger individual. Although the identities of the trackmakers are unknown, the Berowra Creek individual had an estimated body length of between ~80 cm (short-coupled) and 1.35 m (long-coupled), and produced the subaqueous trackway while travelling upslope (against the current) on a sandbar within a braided river system of the Hawkesbury Sandstone. These trackways partially resemble amphibian swim traces in the so-called Batrachichnus C Lunichnium continuum, but appear to represent a unique locomotion trace. This reanalysis of the Berowra Creek trackway provides insight into the locomotion of tetrapods of the Triassic Hawkesbury Series, which remains a poorly understood aspect of their life history.
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Poropat, Stephen F., Matt A. White, Tim Ziegler, Adele H. Pentland, Samantha L. Rigby, Ruairidh J. Duncan, Trish Sloan e David A. Elliott. "A diverse Late Cretaceous vertebrate tracksite from the Winton Formation of Queensland, Australia". PeerJ 9 (17 giugno 2021): e11544. http://dx.doi.org/10.7717/peerj.11544.
Testo completoAbstract (sommario):
The Upper Cretaceous ‘upper’ Winton Formation of Queensland, Australia is world famous for hosting Dinosaur Stampede National Monument at Lark Quarry Conservation Park, a somewhat controversial tracksite that preserves thousands of tridactyl dinosaur tracks attributed to ornithopods and theropods. Herein, we describe the Snake Creek Tracksite, a new vertebrate ichnoassemblage from the ‘upper’ Winton Formation, originally situated on Karoola Station but now relocated to the Australian Age of Dinosaurs Museum of Natural History. This site preserves the first sauropod tracks reported from eastern Australia, a small number of theropod and ornithopod tracks, the first fossilised crocodyliform and ?turtle tracks reported from Australia, and possible lungfish and actinopterygian feeding traces. The sauropod trackways are wide-gauge, with manus tracks bearing an ungual impression on digit I, and anteriorly tapered pes tracks with straight or concave forward posterior margins. These tracks support the hypothesis that at least one sauropod taxon from the ‘upper’ Winton Formation retained a pollex claw (previously hypothesised for Diamantinasaurus matildae based on body fossils). Many of the crocodyliform trackways indicate underwater walking. The Snake Creek Tracksite reconciles the sauropod-, crocodyliform-, turtle-, and lungfish-dominated body fossil record of the ‘upper’ Winton Formation with its heretofore ornithopod- and theropod-dominated ichnofossil record.
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McLoughlin, Stephen, Chris Mays, Vivi Vajda, Malcolm Bocking, Tracy D. Frank e Christopher R. Fielding. "DWELLING IN THE DEAD ZONE—VERTEBRATE BURROWS IMMEDIATELY SUCCEEDING THE END-PERMIAN EXTINCTION EVENT IN AUSTRALIA". PALAIOS 35, n. 8 (27 agosto 2020): 342–57. http://dx.doi.org/10.2110/palo.2020.007.
Testo completoAbstract (sommario):
ABSTRACT A distinctive burrow form, Reniformichnus australis n. isp., is described from strata immediately overlying and transecting the end-Permian extinction (EPE) horizon in the Sydney Basin, eastern Australia. Although a unique excavator cannot be identified, these burrows were probably produced by small cynodonts based on comparisons with burrows elsewhere that contain body fossils of the tracemakers. The primary host strata are devoid of plant remains apart from wood and charcoal fragments, sparse fungal spores, and rare invertebrate traces indicative of a very simplified terrestrial ecosystem characterizing a ‘dead zone' in the aftermath of the EPE. The high-paleolatitude (∼ 65–75°S) setting of the Sydney Basin, together with its higher paleoprecipitation levels and less favorable preservational potential, is reflected by a lower diversity of vertebrate fossil burrows and body fossils compared with coeval continental interior deposits of the mid-paleolatitude Karoo Basin, South Africa. Nevertheless, these burrows reveal the survivorship of small tetrapods in considerable numbers in the Sydney Basin immediately following the EPE. A fossorial lifestyle appears to have provided a selective advantage for tetrapods enduring the harsh environmental conditions that arose during the EPE. Moreover, high-paleolatitude and maritime settings may have provided important refugia for terrestrial vertebrates at a time of lethal temperatures at low-latitudes and aridification of continental interiors.
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Barnes, Richard W., e Robert S. Hill. "Ceratopetalum fruits from Australian cainozoic sediments and their significance for petal evolution in the genus". Australian Systematic Botany 12, n. 5 (1999): 635. http://dx.doi.org/10.1071/sb98014.
Testo completoAbstract (sommario):
Ceratopetalum Sm. fruits are characterised by 4–6 enlarged woody sepals radiating from a central disk, a semi-inferior ovary, anthers between and above each sepal and three-trace sepal venation with a prominent intra-sepal vein. Two new species of Ceratopetalum are described from fruits extracted from Australian Cainozoic sediments, C. westermannii and C. maslinensis. The presence of Ceratopetalum in Middle Eocene Maslin Bay sediments, South Australia, indicates a more widespread geographic distribution for the genus during the Cenozoic. Petally is present in one extant and two fossil species and probably represents the ancestral state despite apetally in the oldest known fossil. Petals have probably been secondarily lost in response to fruit specialisation or a change in pollinator vector.
28
Hartwell, John. "2009 Release of offshore petroleum exploration acreage". APPEA Journal 49, n. 1 (2009): 463. http://dx.doi.org/10.1071/aj08030.
Testo completoAbstract (sommario):
John Hartwell is Head of the Resources Division in the Department of Resources, Energy and Tourism, Canberra Australia. The Resources Division provides advice to the Australian Government on policy issues, legislative changes and administrative matters related to the petroleum industry, upstream and downstream and the coal and minerals industries. In addition to his divisional responsibilities, he is the Australian Commissioner for the Australia/East Timor Joint Petroleum Development Area and Chairman of the National Oil and Gas Safety Advisory Committee. He also chairs two of the taskforces, Clean Fossil Energy and Aluminium, under the Asia Pacific Partnership for Clean Development and Climate (AP6). He serves on two industry and government leadership groups delivering reports to the Australian Government, strategies for the oil and gas industry and framework for the uranium industry. More recently he led a team charged with responsibility for taking forward the Australian Government’s proposal to establish a global carbon capture and storage institute. He is involved in the implementation of a range of resource related initiatives under the Government’s Industry Action Agenda process, including mining and technology services, minerals exploration and light metals. Previously he served as Deputy Chairman of the Snowy Mountains Council and the Commonwealth representative to the Natural Gas Pipelines Advisory Committee. He has occupied a wide range of positions in the Australian Government dealing with trade, commodity, and energy and resource issues. He has worked in Treasury, the Department of Trade, Department of Foreign Affairs and Trade and the Department of Primary Industries and Energy before the Department of Industry, Science and Resources. From 1992–96 he was a Minister Counsellor in the Australian Embassy, Washington, with responsibility for agriculture and resource issues and also served in the Australian High Commission, London (1981–84) as the Counsellor/senior trade relations officer. He holds a MComm in economics, and Honours in economics from the University of New South Wales, Australia. Prior to joining the Australian Government, worked as a bank economist. He was awarded a public service medal in 2005 for his work on resources issues for the Australian Government.
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MacNaughton, Robert B. "Trace Fossils in Evolutionary Palaeoecology. Based on proceedings held in Sydney, Australia, 6–10 July 2002. Fossils and Strata: An International Monograph Series of Paleontology and Stratigraphy, Volume 51. Edited by Barry D Webby, M Gabriela Mángano, and , Luis A Buatois. Oslo (Norway): Taylor & Francis. $50.00 (paper). v + 153 p; ill.; no index. ISSN: 0300‐9491. 2004." Quarterly Review of Biology 80, n. 4 (dicembre 2005): 471. http://dx.doi.org/10.1086/501258.
Testo completo
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Shillito, Anthony P., e Neil S. Davies. "The Silurian inception of inland desert ecosystems: trace fossil evidence from the Mereenie Sandstone, Northern Territory, Australia". Journal of the Geological Society 178, n. 4 (19 febbraio 2021): jgs2020–243. http://dx.doi.org/10.1144/jgs2020-243.
Testo completoAbstract (sommario):
The Silurian was an interval of profound change in terrestrial ecosystems as the earliest non-marine animal communities began to become established on the continents. Whilst much is known about the transition of pioneering animals from shallow-marine to coastal and alluvial habitats, evidence for animal activity in contemporaneous aeolian strata is rare. Here, we present trace fossil evidence that closes this knowledge gap, indicating that Silurian desert environments, dominated by aeolian processes, were occupied by resident invertebrate communities. The evidence comes from the Mereenie Sandstone, Northern Territory, Australia, which is demonstrated to have been deposited in a wet inland aeolian system, typified by small crescentic sand dunes and extensive interdune flats. The invertebrate trace fossil associations from the Mereenie Sandstone (Arenicolites isp., ‘burrow entrance with radial feeding traces', Didymaulichnus lyelli, Diplichnites gouldi, Helminthopsis isp., Laevicyclus isp., Palaeophycus isp., Polarichnus garnierensis, Skolithos isp.) are restricted to damp interdune deposits, whereas dune strata are barren. The ichnofauna are described and compared to those from other Palaeozoic aeolian systems, in order to re-evaluate the timing of the early stages of arthropod terrestrialization.
31
Leal, Patrícia H., Antonio Cardoso Marques e Jose Alberto Fuinhas. "How economic growth in Australia reacts to CO2 emissions, fossil fuels and renewable energy consumption". International Journal of Energy Sector Management 12, n. 4 (5 novembre 2018): 696–713. http://dx.doi.org/10.1108/ijesm-01-2018-0020.
Testo completoAbstract (sommario):
Purpose Australia is one of the ten largest emitters of greenhouse gases but stands out from the others due to its economic growth without recession for 26 consecutive years. This paper aims to focus on the energy-growth nexus and the effects of energy consumption on the environment in Australia. Design/methodology/approach This analysis is performed using annual data from 1965 to 2015 and the autoregressive distributed lag model. Findings The paper finds empirical evidence of a trade-off between economic growth and carbon dioxide (CO2) intensity. The results show that increased gross domestic product (GDP) in Australia increased investment in renewable energy sources (RESs), although the renewable technology is limited and has no impact on reducing CO2 intensity in the long run. In contrast to investment in RES, fossil fuels, coal and oil, are decreased by GDP. However, oil consumption increased renewable energy consumption, and this reflects the pervading effect of the growing economy. Originality/value Overall, this paper contributes to the literature by analysing the behaviour of both energy consumption and the environment on the growing Australian economy. In addition, this paper goes further by studying the impact of economic growth on renewable and non-renewable energy consumption, as well as on CO2 emissions. The study is conducted on a single country for which literature is scarce, using a recent approach and a long time period.
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Herne, Matthew C., Jay P. Nair, Alistair R. Evans e Alan M. Tait. "New small-bodied ornithopods (Dinosauria, Neornithischia) from the Early Cretaceous Wonthaggi Formation (Strzelecki Group) of the Australian-Antarctic rift system, with revision ofQantassaurus intrepidusRich and Vickers-Rich, 1999". Journal of Paleontology 93, n. 3 (11 marzo 2019): 543–84. http://dx.doi.org/10.1017/jpa.2018.95.
Testo completoAbstract (sommario):
AbstractThe Flat Rocks locality in the Wonthaggi Formation (Strzelecki Group) of the Gippsland Basin, southeastern Australia, hosts fossils of a late Barremian vertebrate fauna that inhabited the ancient rift between Australia and Antarctica. Known from its dentary,Qantassaurus intrepidusRich and Vickers-Rich, 1999 has been the only dinosaur named from this locality. However, the plethora of vertebrate fossils collected from Flat Rocks suggests that further dinosaurs await discovery. From this locality, we name a new small-bodied ornithopod,Galleonosaurus dorisaen. gen. n. sp. from craniodental remains. Five ornithopodan genera are now named from Victoria.Galleonosaurus dorisaen. gen. n. sp. is known from five maxillae, from which the first description of jaw growth in an Australian dinosaur is provided. The holotype ofGalleonosaurus dorisaen. gen. n. sp. is the most complete dinosaur maxilla known from Victoria. Micro-CT imagery of the holotype reveals the complex internal anatomy of the neurovascular tract and antorbital fossa. We confirm thatQ. intrepidusis uniquely characterized by a deep foreshortened dentary. Two dentaries originally referred toQ. intrepidusare reassigned toQ.?intrepidusand a further maxilla is referred to cf.Atlascopcosaurus loadsiRich and Rich, 1989. A further ornithopod dentary morphotype is identified, more elongate than those ofQ. intrepidusandQ.?intrepidusand with three more tooth positions. This dentary might pertain toGalleonosaurus dorisaen. gen. n. sp. Phylogenetic analysis recovered Cretaceous Victorian and Argentinian nonstyracosternan ornithopods within the exclusively Gondwanan clade Elasmaria. However, the large-bodied taxonMuttaburrasaurus langdoniBartholomai and Molnar, 1981 is hypothesised as a basal iguanodontian with closer affinities to dryomorphans than to rhabdodontids.UUID:http://zoobank.org/4af87bb4-b687-42f3-9622-aa806a6b4116
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Bolton, Cynthja, Z. Q. Chen e Margaret L. Fraiser. "A new trace-fossil assemblage from the Lower Triassic of Western Australia". Journal of Earth Science 21, S1 (giugno 2010): 115–17. http://dx.doi.org/10.1007/s12583-010-0184-z.
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Tidwell, WD, e AC Rozefelds. "Yulebacaulis normanii gen. et sp. nov., a new fossil tree fern from south-eastern Queensland, Australia". Australian Systematic Botany 4, n. 2 (1991): 421. http://dx.doi.org/10.1071/sb9910421.
Testo completoAbstract (sommario):
Although possibly reworked, a silicified specimen consisting of outer cortex, petioles, aphlebiae and roots was collected from the Lower Cretaceous Mooga Sandstone or Tertiary sediments which lie topographically above the site near Yuleba, Queensland, and represents the new genus and species Yulebacaulis normanii. The petioles in this specimen lack stipular wings and epidermal trichomes or scales. Its clepsydroid-shaped petiolar vascular strands are oblong, straight and elongated tangential to the missing stele. Clusters of parenchyma cells at the ends of the strands form 'peripheral loops' and, at higher levels of the petioles, the 'loops' open, freeing C-shaped aphlebiae traces. Non-filiforrn aphlebiae produced by the petioles are numerous. Yulebacaulis normanii is anatomically similar to Asterochlaenopsis kirgisica (Stenzel) Sahni from the Permian of western Siberia. They differ by the peripheral loops in Y. normanii remaining open after the C-shaped traces depart, rather than staying closed as in A. kirgisica. The trace also begins as a loop in A. kirgisica and not in Y. normanii. Aphlebiae fork repeatedly in the former species and only twice in the latter. Faecal pellets produced by some small animals are present between the petioles, in the aphlebiae, and in borings in the inner and outer cortices of some petioles of Y. normanii. Based upon the size ranges of the faecal pellets, three different animals may have been involved. The pellets are loosely packed, almost filling the galleries, and appear to have been deposited by the animals as they fed upon the cortical cells. The anatomical features of Yulebacaulis are very close to some members of the Zygopteridales. If it is Early Cretaceous in age, then by assigning this genus to this group the age of this order would be extended from Upper Palaeozoic into the mid-Mesozoic.
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Cramwinckel, Margot J., Lineke Woelders, Emiel P. Huurdeman, Francien Peterse, Stephen J. Gallagher, Jörg Pross, Catherine E. Burgess, Gert-Jan Reichart, Appy Sluijs e Peter K. Bijl. "Surface-circulation change in the southwest Pacific Ocean across the Middle Eocene Climatic Optimum: inferences from dinoflagellate cysts and biomarker paleothermometry". Climate of the Past 16, n. 5 (1 settembre 2020): 1667–89. http://dx.doi.org/10.5194/cp-16-1667-2020.
Testo completoAbstract (sommario):
Abstract. Global climate cooled from the early Eocene hothouse (∼52–50 Ma) to the latest Eocene (∼34 Ma). At the same time, the tectonic evolution of the Southern Ocean was characterized by the opening and deepening of circum-Antarctic gateways, which affected both surface- and deep-ocean circulation. The Tasmanian Gateway played a key role in regulating ocean throughflow between Australia and Antarctica. Southern Ocean surface currents through and around the Tasmanian Gateway have left recognizable tracers in the spatiotemporal distribution of plankton fossils, including organic-walled dinoflagellate cysts. This spatiotemporal distribution depends on both the physicochemical properties of the water masses and the path of surface-ocean currents. The extent to which climate and tectonics have influenced the distribution and composition of surface currents and thus fossil assemblages has, however, remained unclear. In particular, the contribution of climate change to oceanographic changes, superimposed on long-term and gradual changes induced by tectonics, is still poorly understood. To disentangle the effects of tectonism and climate in the southwest Pacific Ocean, we target a climatic deviation from the long-term Eocene cooling trend: the Middle Eocene Climatic Optimum (MECO; ∼40 Ma). This 500 kyr phase of global warming was unrelated to regional tectonism, and thus provides a test case to investigate the ocean's physicochemical response to climate change alone. We reconstruct changes in surface-water circulation and temperature in and around the Tasmanian Gateway during the MECO through new palynological and organic geochemical records from the central Tasmanian Gateway (Ocean Drilling Program Site 1170), the Otway Basin (southeastern Australia), and the Hampden Beach section (New Zealand). Our results confirm that dinocyst communities track specific surface-ocean currents, yet the variability within the communities can be driven by superimposed temperature change. Together with published results from the east of the Tasmanian Gateway, our new results suggest a shift in surface-ocean circulation during the peak of MECO warmth. Simultaneous with high sea-surface temperatures in the Tasmanian Gateway area, pollen assemblages indicate warm temperate rainforests with paratropical elements along the southeastern margin of Australia. Finally, based on new age constraints, we suggest that a regional southeast Australian transgression might have been coincident with the MECO.
36
Gehling, James G., e Mary L. Droser. "Ediacaran scavenging as a prelude to predation". Emerging Topics in Life Sciences 2, n. 2 (28 settembre 2018): 213–22. http://dx.doi.org/10.1042/etls20170166.
Testo completoAbstract (sommario):
Predation is one of the most fundamental ecological and evolutionary drivers in modern and ancient ecosystems. Here, we report the discovery of evidence of the oldest scavenging of shallowly buried bodies of iconic soft-bodied members of the Ediacara Biota by cryptic seafloor mat-burrowing animals that produced the furrow and levee trace fossil, Helminthoidichnites isp. These mat-burrowers were probably omnivorous, stem-group bilaterians that largely grazed on microbial mats but when following mats under thin sands, they actively scavenged buried Dickinsonia, Aspidella, Funisia and other elements of the Ediacara Biota. These traces of opportunistic scavengers of dead animals from the Ediacaran of South Australia represent a fundamental ecological innovation and a possible pathway to the evolution of macrophagous predation in the Cambrian. While the Ediacaran oceans may have had oxygen levels too low to support typical large predators, the Helminthoidichnites maker lived in and grazed on microbial mats, which may have provided a localized source of oxygen.
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Brasier, Martin D., e David Wacey. "Fossils and astrobiology: new protocols for cell evolution in deep time". International Journal of Astrobiology 11, n. 4 (7 settembre 2012): 217–28. http://dx.doi.org/10.1017/s1473550412000298.
Testo completoAbstract (sommario):
AbstractThe study of life remote in space has strong parallels with the study of life remote in time. Both are dependent on decoding those historic phenomena called ‘fossils’, here taken to include biogenic traces of activity and waste products. There is the shared problem of data restoration from incomplete data sets; the importance of contextual analysis of potentially viable habitats; the centrality of cell theory; the need to reject the null hypothesis of an abiogenic origin for candidate cells via morphospace analysis; the need to demonstrate biology-like behaviour (e.g., association with biofilm-like structures; tendency to form clusters and ‘mats’; and a preference for certain substrates), and of metabolism-like behaviour (e.g., within the candidate cell wall; within surrounding ‘waste products’; evidence for syntrophy and metabolic cycles; and evidence for metabolic tiers). We combine these ideas into a robust protocol for demonstrating ancient or extra-terrestrial life, drawing examples from Earth's early geological record, in particular from the earliest known freshwater communities of the 1.0 Ga Torridonian of Scotland, from the 1.9 Ga Gunflint Chert of Canada, from the 3.4 Ga Strelley Pool sandstone of Australia, and from the 3.46 Ga Apex Chert also of Australia.
38
Bengtson, Stefan, Birger Rasmussen e Bryan Krapež. "The Paleoproterozoic megascopic Stirling biota". Paleobiology 33, n. 3 (2007): 351–81. http://dx.doi.org/10.1017/s0094837300026348.
Testo completoAbstract (sommario):
AbstractThe 2.0–1.8-billion-year-old Stirling Range Formation in southwestern Australia preserves the deposits of a siliciclastic shoreline formed under the influence of storms, longshore currents, and tidal currents. Sandstones contain a megascopic fossil biota represented by discoidal fossils similar to the Ediacaran Aspidella Billings, 1872, as well as ridge pairs preserved in positive hyporelief on the soles of channel-fill sandstones bounded by mud drapes. The ridges run parallel or nearly parallel for most of their length, meeting in a closed loop at one end and opening with a slight divergence at the opposite end. The ridges are interpreted as casts of sediment-laden mucus strings formed by the movement of multicellular or syncytial organisms along a muddy surface. The taxa Myxomitodes stirlingensis n. igen., n. isp., are introduced for these traces. The Stirling biota was roughly coeval with other presumed multicellular eukaryotes appearing after a long period of profound environmental changes involving a rise in ambient oxygen levels, similar to that which preceded the Cambrian explosion. The failure of multicellular life to diversify during most of the Proterozoic may be due to environmental constraints related to the comparatively low level of oxidation of the world oceans.
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Bengtson, Stefan, Birger Rasmussen e Bryan Krapež. "The Paleoproterozoic megascopic Stirling biota". Paleobiology 33, n. 3 (2007): 351–81. http://dx.doi.org/10.1666/04040.1.
Testo completoAbstract (sommario):
AbstractThe 2.0–1.8-billion-year-old Stirling Range Formation in southwestern Australia preserves the deposits of a siliciclastic shoreline formed under the influence of storms, longshore currents, and tidal currents. Sandstones contain a megascopic fossil biota represented by discoidal fossils similar to the Ediacaran Aspidella Billings, 1872, as well as ridge pairs preserved in positive hyporelief on the soles of channel-fill sandstones bounded by mud drapes. The ridges run parallel or nearly parallel for most of their length, meeting in a closed loop at one end and opening with a slight divergence at the opposite end. The ridges are interpreted as casts of sediment-laden mucus strings formed by the movement of multicellular or syncytial organisms along a muddy surface. The taxa Myxomitodes stirlingensis n. igen., n. isp., are introduced for these traces. The Stirling biota was roughly coeval with other presumed multicellular eukaryotes appearing after a long period of profound environmental changes involving a rise in ambient oxygen levels, similar to that which preceded the Cambrian explosion. The failure of multicellular life to diversify during most of the Proterozoic may be due to environmental constraints related to the comparatively low level of oxidation of the world oceans.
40
McLoughlin, Stephen. "New records of leaf galls and arthropod oviposition scars in Permian - Triassic Gondwanan gymnosperms". Australian Journal of Botany 59, n. 2 (2011): 156. http://dx.doi.org/10.1071/bt10297.
Testo completoAbstract (sommario):
Single, midrib-positioned galls and midrib-flanking oviposition scars are described from four species of Permian glossopterid foliage from Australia and South Africa. Several of these traces have been mistaken previously for glossopterid reproductive organs or fructification detachment scars. A single Early Triassic corystosperm leaf from Australia is reported bearing multiple disc-like galls on both the midrib and pinnules. A Middle Triassic taeniopterid gymnosperm leaf from Australia is described hosting oviposition scars between consecutive secondary veins flanking the midrib. These fossils attest to a much richer record of plant–arthropod interactions in the late Palaeozoic and early Mesozoic of high-latitude Gondwana than previously reported, and indicate that herbivory and reproductive strategies involving galling and foliar ovipositioning were re-established relatively soon after the end-Permian mass extinction event that saw major turnovers in both the flora and insect fauna.
41
Teixeira, João C., e Alan Cooper. "Using hominin introgression to trace modern human dispersals". Proceedings of the National Academy of Sciences 116, n. 31 (12 luglio 2019): 15327–32. http://dx.doi.org/10.1073/pnas.1904824116.
Testo completoAbstract (sommario):
The dispersal of anatomically modern human populations out of Africa and across much of the rest of the world around 55 to 50 thousand years before present (ka) is recorded genetically by the multiple hominin groups they met and interbred with along the way, including the Neandertals and Denisovans. The signatures of these introgression events remain preserved in the genomes of modern-day populations, and provide a powerful record of the sequence and timing of these early migrations, with Asia proving a particularly complex area. At least 3 different hominin groups appear to have been involved in Asia, of which only the Denisovans are currently known. Several interbreeding events are inferred to have taken place east of Wallace’s Line, consistent with archaeological evidence of widespread and early hominin presence in the area. However, archaeological and fossil evidence indicates archaic hominins had not spread as far as the Sahul continent (New Guinea, Australia, and Tasmania), where recent genetic evidence remains enigmatic.
42
Sharma, Prakash, Flor Lucia De la Cruz e Jonathan Sultoon. "Finding winners in the hydrogen hype". APPEA Journal 62, n. 2 (13 maggio 2022): S67—S71. http://dx.doi.org/10.1071/aj21168.
Testo completoAbstract (sommario):
The global energy trade is set for its greatest transformation since the 1970s and the rise of OPEC (The Organization of the Petroleum Exporting Countries). Electrification is central to this as countries plough money into renewables to reduce emissions and enhance energy security. But electrification can take the world only so far. With higher carbon prices looming on the horizon, fossil fuel exporters and industrial sectors – as well as heavy-duty trucking, shipping and aviation – need alternatives to decarbonise. Most are looking to electricity-based fuels and feedstocks such as hydrogen, ammonia and methanol to replace hydrocarbons. This will revolutionise energy trade, with total trade declining by as much as 50% and virtually all remaining traded oil gas and coal being either completely decarbonised or backed by offsets. With 147 GWel (giga‐watts electrolyser capacity) in announced projects, green hydrogen produced from renewable electricity is ahead of the game. And while its export supply chains are complex, requiring conversion into a ‘product’ to allow delivery, there is no exploration risk as in oil and gas projects. Worldwide, national hydrogen roadmaps are being passed, with virtually all oil and gas companies, utilities and industrials backing at least one hydrogen project. Focus is now shifting to future sources of hydrogen supply. Lenders will be drawn to locations with a proven track record of exporting natural resources, suitable conditions for low-cost renewable electricity and the potential for large-scale carbon capture. A few countries already stand out, but none more so than Australia. Using our proprietary research, we will present a case study evaluating hydrogen supply options from Australia, Saudi Arabia and Canada – delivered into key markets like Japan for different applications. We will also assess when costs will fall across the value chain – production, midstream and downstream – and reach parity to incumbent fuels.
43
Mathur, V. K. "Ediacaran multicellular biota from Krol Group, Lesser Himalaya and its stratigraphic significance-a review". Journal of Palaeosciences 57, n. (1-3) (31 dicembre 2008): 53–61. http://dx.doi.org/10.54991/jop.2008.227.
Testo completoAbstract (sommario):
Ediacaran multicellular biota, viz. medusoids - Kimberella cf. quadrata, Beltanella cf. gilesi, Cyclomedusa davidi, Conomedusites lobatus, Tirasiana sp., Medusinites asteroides, Sekwia cf. excentrica, Irridinitus sp. and Beltanelliformis cf. brunsae; frondoids - Charniodiscus cf. arboreus, Pteridinium cf. simplex and Zolotytsia biserialis; annelid – Dickinsonia sp.; ichnofossils - Bilinichnus sp. and metaphytic algae- cf. Proterotaenia montana, has been recorded from the Kauriyala Formation (Upper Krol) of the Krol Group, Lesser Himalaya India. The underlying Jarashi Formation (Middle Krol) has yielded frondoid forms - Pteridinium carolinaense and Charniodiscus cf. arboreus and trace fossil - Harlaniella sp. whereas the Mahi Formation (Lower Krol) has yielded medusoid - Nimbia cf. occlusa. This biota is generally cosmopolitan in nature except Dickinsonia which is restricted to Protogondwana. The Ediacaran biota is preserved at the interface of arenite / siltstone and shale which show ripple marks, rhythmic and lenticular bedding at places suggestive of tidal flat environment.
The present biota is comparable with Ediacaran multicellular biota of Ediacaran (Terminal Neoproterozoic) Period known from Australia, Canada and Russia. The fossiliferous horizons are characterised by dC13 values that vary from +1% to +6% PDB. Similar isotopic signatures have also been described from other Ediacaran fossil bearing horizons from northwestern Canada, Namibia, Australia, China and north Siberia.
44
Moss, S., D. Barr, R. Kneale, P. Clews e T. Cruse. "MID TO LATE JURASSIC SHALLOW MARINE SEQUENCES OF THE EASTERN BARROW SUB-BASIN: THE ROLE OF LOW-STAND DEPOSITION IN NEW EXPLORATION CONCEPTS". APPEA Journal 43, n. 1 (2003): 231. http://dx.doi.org/10.1071/aj02012.
Testo completoAbstract (sommario):
Several wells drilled along the fault-terraced eastern margin of the Barrow Sub-basin of the Australian North West Shelf have shed light on the pattern of Callovian to Tithonian sedimentation in the area. Much of this section has historically been interpreted as a product of deep marine depositional environments.Sandstone reservoirs cored in Linda–1/ST1, Linda–2 (both Wanaea spectabilis b age) and Denver–1/ST1 (Rigaudella aemula age) exhibit coarsening-upward cycles typical of marine parasequences, and possess sharp, erosive lower contacts with underlying claystone. In the case of Denver–1/ST1, the sandstones are heavily bioturbated with a distinct shallow marine trace fossil assemblage. Burrows are less evident in the sandstones from the Linda wells, although several thin bioturbated horizons—also with shallow marine trace fossils—are encountered. Similar patterns of shallow marine deposition are observed in previously drilled wells within the study area, and evidence of pedogenesis is found in core from Georgette–1 (R. aemula age), suggesting that exposure occurred on some of the higher fault terraces during low-stand conditions in the Middle to Late Jurassic.Further to the west, deepwater submarine fan sediments, deposited during low-stands, have been recognised. A range of time equivalent low-stand deposits—which are spatially and genetically exclusive— therefore exists within the sub-basin. Indeed such a spectrum should be expected in complex and tectonically active areas such as the Jurassic Barrow Sub-basin.The recognition of shallow marine deposits in the area has major implications with respect to the location and geometry of reservoir sandstones. The low-stand shoreface model, as opposed to the deep marine turbidite model, leads to the prediction of sandstone deposition aligned roughly parallel—rather than perpendicular— to the palaeo-shoreline and the potential for deeperwater sandstones further downdip.
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DWORSCHAK, PETER C., e SÉRGIO DE A. RODRIGUES. "A modern analogue for the trace fossil Gyrolithes: burrows of the thalassinidean shrimp Axianassa australis". Lethaia 30, n. 1 (29 marzo 2007): 41–52. http://dx.doi.org/10.1111/j.1502-3931.1997.tb00443.x.
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Beck, Dr Tony. "INTERNATIONAL CLIMATE CHANGE: POLICY AND ACTION". APPEA Journal 34, n. 2 (1994): 93. http://dx.doi.org/10.1071/aj93088.
Testo completoAbstract (sommario):
The Framework Convention on Climate Change, first negotiated at the Rio 'Earth Summit', has recently been ratified by the required 50 countries. Now that the Convention has come into force the pace of implementation will quicken with important implications for Australia and world trade. Developed countries, including Australia, are likely to be under significant pressure to strengthen the emission control commitments they made at Rio.For a country like Australia with growing energy demand and a dependence on fossil fuels, the potential costs of meeting stringent greenhouse emission constraints are high, both in terms of domestic economic costs and lost export markets. We need to be vigilant with respect to policy developments in other countries and need to ensure that domestic greenhouse policies are appropriate to our circumstances.The recent International Negotiating Committee (INC9) meeting in Geneva gives an indication of the direction of international policy developments and a forewarning of the potential dangers for Australia. This paper reviews the outcomes of INC9 and considers the implications of these developments for Australia.
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Komarova, A. V. "The main instruments of state regulation of the transformation of the fuel and energy balance". Interexpo GEO-Siberia 2, n. 4 (18 maggio 2022): 165–70. http://dx.doi.org/10.33764/2618-981x-2022-2-4-165-170.
Testo completoAbstract (sommario):
The aim of the study is to analyze the experience of energy transition management policies in major fossil fuel exporting countries. The change in the structure of the fuel and energy balance in Canada, Australia, Norway, as well as Russia and the EU is assessed. The main trends associated with a significant decrease in the share of coal used and an increase in the share of natural gas and renewable energy sources for all the objects under consideration are identified. The analysis of carbon regulation policy revealed significant differences in the main applied principles. While Australia has a voluntary system of de facto subsidies for low-carbon activities, Canada is dominated by regional mandatory regulation, and Norway uses both tax instruments and EU cap-and-trade system.
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Luo, Mao, e G. R. Shi. "First record of the trace fossil Protovirgularia from the Middle Permian of southeastern Gondwana (southern Sydney Basin, Australia)". Alcheringa: An Australasian Journal of Palaeontology 41, n. 3 (16 febbraio 2017): 335–49. http://dx.doi.org/10.1080/03115518.2017.1283052.
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Kondo, Yutaka, Nobuyuki Takegawa, Yuzo Miyazaki, Malcolm Ko, Makoto Koike, Kazuyuki Kita, Shuji Kawakami et al. "Effects of biomass burning and lightning on atmospheric chemistry over Australia and South-east Asia". International Journal of Wildland Fire 12, n. 4 (2003): 271. http://dx.doi.org/10.1071/wf03014.
Testo completoAbstract (sommario):
In situ aircraft measurements of trace gases and aerosols were made in the boundary layer (BL) and free troposphere (FT) over Indonesia and Australia during the Biomass Burning and Lightning Experiment (BIBLE)-A and B conducted in August–October 1998 and 1999.Concentrations of ozone (O3) and its precursors [CO, reactive nitrogen (NOx), non-methane hydrocarbons (NMHCs)] were measured in these campaigns to identify the sources of NOx and to estimate the effects of biomass burning and lightning on photochemical production of O3. Over Indonesia, in-situ production of NOx by lightning was found to be a major source of reactive nitrogen in the upper troposphere during BIBLE-A. In some circumstances, increases in reactive nitrogen were often associated with enhancements in CO and NMHCs, suggesting that the sources were biomass burning and fossil fuel combustion, followed by upward transport by cumulus convection. Over Australia the levels of O3, CO, reactive nitrogen, and NMHCs were elevated throughout the troposphere compared to those observed in the tropical Pacific. However, the mechanisms responsible for the enhanced concentrations in the BL and FT are distinctly different. The emissions from biomass burning that occurred in northern Australia were restricted to the BL because of strong subsidence in the period. In the FT over Australia, elevated concentrations of O3 and its precursors result from injections of emissions as the air masses travel over Africa, South America, the Indian Ocean, and Indonesia en route to Australia. In all cases, O3 levels in the biomass burning plumes were enhanced due to photochemical production.
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Nesterovsky, V. A., A. I. Martyshyn e A. M. Chupryna. "New biocenosis model of Vendian (Ediacaran) sedimentation basin of Podilia (Ukraine)". Journal of Geology, Geography and Geoecology 27, n. 1 (10 luglio 2018): 95–107. http://dx.doi.org/10.15421/111835.
Testo completoAbstract (sommario):
The aim of this study is to fully research all aspects of the distribution, development, conditions of burial and preservation of the Ediacaran biocomplex. Thiswork summarizes and extends all data on the unique Vendian invertebrates that are distributed in the natural and artificial outcrops of the Dniester River Basin within Podilia (Ukraine). One of the basic locations of the annual observation was a quarry of rubble stone production near the Dniester hydroelectric station-1, Novodnistrovsk city, which exposes a continuous section of the deposits of the Lomoziv, Yampil, Lyadova and Bernashivka Beds lying on a crystalline basement. This paper shows the outcomes of long-term fieldwork of the Upper Ediacaran which include deposits of the Mogyliv-Podilsky and Kanylivka Group. The researched section is characterized by its clastic composition and the absence of carbonate formations. The basic paleontological collection has more than two thousand specimens, for instance, the imprints of molluscous fauna, traces of their live activity, the remains of flora and fossils of a problematic nature. The most numerous and informative collection of these fossils is located in the stock of the Geological Museum of the Taras Shevchenko National University of Kyiv. The collection contains unique material, including a number of Ediacaran fossils described for the first time. On the whole within Podilia region, more than 100 species have been described in detail. The main areas of biota accumulation in the outcrops are associated with argillites, argillite-siltstones and their contact with sandstones. The best preservation of the imprints is detected in the boundary of facial transitions. Research has revealed that there is a decrease in the numerical and species composition of the molluscous biota, and the dynamic increase in evolution of burrowing organisms and plants within the Podilia Basin during the late Vendian. Such a phenomenon led to an environmental change, increase in oxygen and appearance of new groups of organisms that were subsequently displaced invertebrates. This occurred at the Precambrian/Cambrian transition, and in the geological literature is described as the «Cambrian explosion». Studies have found that the total number of taxonomic composition of the Eidacaran in Podilia is similar to the orictocoenosis of Southern Australia and the White Sea. Nevertheless, the Podilia biocomplex is more ancient than the Southern Australian and the White Sea, it is much younger than the Avallonian.