After initially training as a geologist, my main work has been university teaching in the disciplines of geology, physical geography, environmental science and palaeobiology. I am currently a Senior Lecturer, and the Bachelor of Science Course Director at Deakin University and hold an Honorary Associate appointment at Museums Victoria.I have research interests in the fields of marine micropalaeontology, palaeoceanography and sedimentary geology. Phone: 61-3-92517622 Address: Deakin University (Melbourne Campus), 221 Burwood Highway, Burwood, Victoria, 3125, Australia
Early Pliocene ostracod faunas of the Jemmys Point Formation, onshore Gippsland Basin, yield a ri... more Early Pliocene ostracod faunas of the Jemmys Point Formation, onshore Gippsland Basin, yield a rich and well-preserved marine ostracod fauna of mixed shallow marine and deep marine origins. The ostracod faunas evidence a marine continental shelf palaeoenvironment that, during the deposition of one stratigraphic interval, was influenced by a strong, persistent upwelling current. This upwelling current allowed the migration of deep-sea Ostracoda (Philoneptunus sp.) onto the continental shelf. The deeper marine aspect of this early Pliocene fauna, and of modern ostracod faunas from the Bass Strait region, evidence the adaptation of deep shelf taxonomic clades to shallow cool temperate shelf environments and highlights one unusual evolutionary mechanism that has contributed to modern Bass Strait shallow marine biodiversity. Four species are newly described: Neonesidea chapminuta sp. nov., Tasmanocypris salaputia sp. nov., Oculocytheropteron jemmyensis sp. nov., and Philoneptunus plutonis sp. nov.
The Lower Devonian (Emsian) Norton Gully Sandstone contains rich invertebrate fossil faunas inclu... more The Lower Devonian (Emsian) Norton Gully Sandstone contains rich invertebrate fossil faunas including ostracods. Seven ostracod taxa are recognized and illustrated herein: Bungonibeyrichia copelandi, Bungonibeyrichia wooriyallockensis, Bungonibeyrichia treslata sp. nov., Bungonibeyrichia australiae, Bairdiocypris sp., and two indeterminate genera. The ostracods are preserved in sandstone and mudstone as natural moulds. There are two distinct biofacies identified within the Norton Gully Sandstone: one dominated by ornate ostracods belonging to Bungonibeyrichia; and the other by smooth species of Bairdiocypris. We also conclude that most southeast Australian species previously placed in Velibeyrichia are more appropriately placed in Bungonibeyrichia on the basis of lobe morphology. Consequently, both these genera can be recognized as having discrete Silurian-Devonian palaeobiogeographical distributions, with Velibeyrichia spp. occurring in the shallow seas of Laurentia, while Bungonibeyrichia spp. was restricted to shallow seas around eastern Gondwana.
The uppermost Miocene Bookpurnong Formation within the Murray Basin of southeastern Australia ove... more The uppermost Miocene Bookpurnong Formation within the Murray Basin of southeastern Australia overlies a regionally extensive subaerial unconformity formed by relatively low late Miocene eustatic sea levels, and the initial phase of the Kosciuszko Uplift tectonic event. A diverse marine fossil ostracod fauna has been recovered from the Bookpurnong Formation, and is associated with a marine transgression that flooded inland regions of southeastern Australia to form a shallow epicontinental sea. Many of the Bookpurnong Formation ostracods represent immigrant taxa, with species such as Puriana lubbockiana, evidencing a subtropical range expansion of thermophilic warm water forms into southern mid latitudes. We attribute this to warm plumes from the East Australian Current, which would have impacted southeastern Australia at that time. In general, the Bookpurnong Formation ostracod assemblages indicate low to moderate energy shallow offshore palaeoenvironments subject to warm-temperate and subtropical conditions. One new genus and five new species are described: Fortistriginglymus gen. nov., Bradyleberis praecristatella sp. nov., Callistocythere bookpurnongensis sp. nov., Callistocythere mchenryi sp. nov., Callistocythere zigzaga sp. nov., and Parakeijia notoreticularis sp. nov.
The ‘Illaenus’ band of the Costerfield Siltstone in the Costerfield-Heathcote area contains pocke... more The ‘Illaenus’ band of the Costerfield Siltstone in the Costerfield-Heathcote area contains pockets of Silurian (lower Wenlock) deposits that contain a rich invertebrate fauna. Several assemblages from the ‘Illaenus’ band have been described and include ostracod species referable to 13 genera. These specimens were housed at the Australian Government Bureau of Mineral Resources in Canberra, which was damaged by fire in 1953. Of the documented ostracod specimens, only three remain, but are in a degraded state. We reinterpret this historically important material as representing the types of Ctenobolbina proxima and Kayatia prima.
Volcanic rocks occur in different types of sedimentary basins, especially those evolving from lit... more Volcanic rocks occur in different types of sedimentary basins, especially those evolving from lithospheric stretching. While volcanoes and other igneous rocks are widespread in the onshore Otway Basin, well-preserved volcanoes have not been documented in the offshore portion of the basin. Here, we analysed high-quality 2-D and 3-D seismic reflection datasets to investigate the origin and distribution of the enigmatic, kilometre-scale buried mound-shaped structures in the Prawn Platform, offshore Otway Basin. Detailed seismic characterisation enabled the identification of 19 mounds, ranging from ~90–400 m in height and 1.8–6 km in diameter. Relatively small (~0.2–11 km2) igneous sills are associated with these mounds. Based on their external geometries and internal seismic architectures, we interpret these mounds as dyke-fed shield volcanoes. Distinct seismic facies characterise the buried volcanoes, including the main volcanic eruption centre, tuff cone, and pyroclastic mass-wasting deposits. Interbedded extrusive and sedimentary rocks are mainly observed within volcanoes over 250 m high, and are associated with gullies along their flanks, indicating these volcanoes may have been subject to erosion. The volcanoes occur at three stratigraphic levels: late Eocene (~37 Ma), mid-Oligocene (~27–29 Ma), and early Miocene (~20 Ma), within the age of the Older Volcanics of the southern Australian margin. We propose that this newly discovered volcanism in the offshore Otway Basin was caused by edge-driven convection (similar mechanism to adjacent onshore volcanism), associated with the fast spreading rate of the Southern Ocean since the late Eocene (~40 Ma). The discovery of these buried volcanoes extends our understanding of magmatism in the Otway Basin, especially regarding the offshore extension of the Older Volcanics.
The Plio-Pleistocene Whalers Bluff Formation (WBF) of the offshore Otway Basin is composed of mix... more The Plio-Pleistocene Whalers Bluff Formation (WBF) of the offshore Otway Basin is composed of mixed siliciclastic- carbonate sediments. In seismic cross sections, this formation includes an interval that consists of higher amplitude seismic reflections that display alternating depressional ponds and raised ridges. This interval is shallowly buried and lies between 40 and 150 ms two-way traveltime below the present-day seafloor. In this study, we have used 2D and 3D seismic data sets in combination with the available shallow subsurface well logs to characterize the geomorphology and investigate the origin of these enigmatic features. The ponds are expressed as densely packed, circular to polygonal, and in some cases, hexagonal-shaped features in time slice maps, and they closely resemble previously documented honeycomb structures. In our study area, the honeycomb-like structures (HS) are comprised of large (200–800mdiameter range) depressed ponds that are separated by narrow (approximately 20m at the top) reticulate ridges. In total, these HS cover an area of 760 km2. Geospatial analysis shows that the ponds of HS, especially those in the northeast of the study area, are aligned along the northwest–southeast trend lines. There are several possible origins for the HS. The most probable mechanism is that the HS resulted from the bulk contraction of soft sediment, associated with shallow-burial diagenesis processes such as subaqueous dewatering of the fine-grained successions within the WBF. Interestingly, irregular furrows of various lengths on the seafloor correspond to the ridges of the HS, and we hypothesize that these furrows may have formed due to differential compaction of the underlying alternating ponds and ridges. Our results demonstrate the benefits of using seismic reflection data sets in combination with geospatial analysis to investigate the buried paleogeomorphologic features and their impact on the present-day seafloor physiography.
A continental shelf to upper continental slope ostracod fauna is documented from the late Cretace... more A continental shelf to upper continental slope ostracod fauna is documented from the late Cretaceous (late Turonian to Santonian) Belfast Mudstone in Voluta-1 of the Otway Basin, southeastern Australia. The fauna has palaeobiogeographical affinities with mid-late Cretaceous ostracod faunas of Western Australia, New Zealand, the Antarctic Peninsula and the Falklands Plateau. This distribution pattern probably reflects dispersal influenced by the opening of the Australo-Antarctic Gulf, and by clockwise gyre currents in the proto Southern Ocean. The presence of Philoneptunus sp. in this fauna suggests that the Australo-Antarctic Gulf was an important locus for deep sea colonization by Gondwanan neritic ostracod clades.
A new fossil paracypridine ostracod, Tasmanocypris lochardi sp.nov. is described from late Miocen... more A new fossil paracypridine ostracod, Tasmanocypris lochardi sp.nov. is described from late Miocene shallow marine strata of southeastern Australia. It has morphological features similar to a number of modern southern Australian and southwest African Tasmanocypris species, here termed the dartnalli-group. This species group was likely present in early Cenozoic temperate, shallow seas around Antarctica. The first appearance of Tasmanocypris lochardi in late Miocene marine strata of the Bass Strait hinterland of SE Australia, equates to a late Miocene (9–7 Ma) intensification and northward latitudinal shift of the Antarctic Circumpolar Current (ACC). Late Miocene occurrences of Tasmanocypris lochardi in southeast Australia were likely associated with temperate eastward flows of the ACC north of the Subantarctic Front. During the early Pliocene, the warm Zeehan Current (aka Leeuwin Current) replaced the ACC as the dominant easterly flowing current across Bass Strait, and this 4.4 Ma palaeoceanographical event correlates with the temporary, but widespread disappearance of T. lochardi from southeast Australian marine waters. However, the presence of refugia populations of T. lochardi along the east Australian continental shelf between 4.4 and 3.4 Ma, likely enabled the brief re establishment of T. lochardi in the east of Bass Strait during the late Pliocene (3.2–3.0 Ma). Tasmanocypris lochardi became permanently extinct in this region during the latest Pliocene to early Pleistocene (< 2.6 Ma), broadly correlating with the onset of the global Quaternary glaciation, and inception of the cold Bass Cascade winter current within Bass Strait.
Known occurrences of the ostracod genus Velibeyrichia are restricted to a number of Silurian to L... more Known occurrences of the ostracod genus Velibeyrichia are restricted to a number of Silurian to Lower Devonian geological strata in North America: the McKenzie Member of the Mifflintown Formation of Maryland and West Virginia; the Tonoloway Limestone of Maryland, West Virginia, Virginia and Pennsylvania; the Bloomsburg Formation of Maryland, Virginia and Pennsylvania; the Manlius Limestone of New York; and the Decker Limestone of New Jersey and New York. The genus includes six species: V. moodeyi (type species), V. mesleri, V. paucigranulosa, V. reticulosaccula, V. tonolowayensis and V. tricornia. The diagnostic combination of characters for this genus are: distinct deflection of the velum where it crosses the crumina in heteromorphs (adult female specimens), dorsal nodes on lobes L1 and L3, sexual dimorphism of the velum, and in tecnomorph specimens, either a shallow sulcus on lobe L3 or a zygal ridge (in adult tecnomorph specimens) extending from lobe L2 to lobe L3. The presence of one or the other of the latter two characters defines two distinct species groups.
Alcheringa: An Australasian Journal of Palaeontology, 2017
The abundant and diverse beyrichioid ostracod faunas preserved in Silurian and Devonian silisicla... more The abundant and diverse beyrichioid ostracod faunas preserved in Silurian and Devonian silisiclastic strata of the Lachlan Orogen in southeastern
Australia include specimens of the genus Bungonibeyrichia. Bungonibeyrichia copelandi sp. nov. is proposed for the fossil material, originally
misidentified at species level, on which the description of this genus was based. The new species is nominated as the type species for Bungonibeyrichia
in accordance with Article 70.3 of the International Code of Zoological Nomenclature. Bungonibeyrichia is distinguished from other
beyrichioid genera on the basis of a distinctive combination of lobe, velum and crumina features.
Three closely allied shallow marine taxa, Neohornibrookella sorrentae (Chapman and Crespin), Neoh... more Three closely allied shallow marine taxa, Neohornibrookella sorrentae (Chapman and Crespin), Neohornibrookella glyphica (Neil), and Neohornibrookella nepeani sp. nov. are recorded from latest early Miocene to late Pliocene strata in southeastern Australia. These taxa, together with Neohornibrookella quadranodosa (Holden) from the Miocene of Midway Island (Northwestern Hawaiian Islands), form a morphologically distinct group of relatively large species (the sorrentae-group) within the genus Neohornibrookella Jellinek. Latitudinal expansion of the subtropical and warm-temperate climatic belts together with the influence of warm western boundary surface currents associated with the North and South Pacific gyres, are likely to have played key roles in the Miocene dispersal of this species group. Species of the sorrentae-group first migrated south from equatorial west Pacific regions into southeastern Australia during the early Miocene, under the influence of the East Australian Current. During three time intervals (i) latest early Miocene, (ii) latest late Miocene and (iii) earliest late Pliocene, forceful pulses of the East Australian Current played a significant role in propelling the widespread distribution of thermophilic Neohornibrookella species across southeast Australian shallow marine realms. During intervening middle and late Miocene times, Neohornibrookella species are only sporadically present across the Bass Strait region of southeast Australia, indicating a weaker East Australian Current influence and the cooling influence of coastal upwelling. During the mid early Pliocene Neohornibrookella species disappeared from the western Bass Strait region, suggesting the complete exclusion of East Australian Current waters from this region. This was probably due to the counteracting influence of the eastward flowing Zeehan Current (extension of the Leeuwin Current) impinging on the western Bass Strait region. This mid early Pliocene palaeobiogeographical partition in Bass Strait, defined by the distribution of sorrentae-group species, is here termed the Bassian Gateway. The two species, N. sorrentae and N. glyphica, occur concurrently during the mid Miocene in southeast Australia, but are associated with different lithofacies. It is hypothesised that there is a heterochronic evolutionary relationship expressed in the ornament of these two species. The thaerocytherid genera Neohornibrookella Jellinek, Tenedocythere Sissingh and Bosasella Bonaduce are here included in the new ostracod subfamily Tenedocytherinae.
(URL: http://www.sciencedirect.com/science/article/pii/S0377839816300251)
Alcheringa: An Australasian Journal of Palaeontology, 2014
ABSTRACT The Humevale Siltstone (late Silurian to Early Devonian, Gorstian to Pragian) and Woori ... more ABSTRACT The Humevale Siltstone (late Silurian to Early Devonian, Gorstian to Pragian) and Woori Yallock Formation (Early Devonian, Emsian) of central Victoria, Australia, contain rich invertebrate fossil faunas including Ostracoda. Eight ostracod taxa are recognized and illustrated herein: Velibeyrichia wooriyallockensis (Chapman), Velibeyrichia (s.l.) australiae (Chapman), Velibeyrichia sp. 1, Velibeyrichia sp. 2, Beyrichia? ligatura (Chapman), Ulrichia sp., Euglyphella sp. and Strepulites sp. The ostracods are preserved in siltstones and mudstones as natural moulds. Ostracod assemblages are mainly shallow marine and likely include moderate- to low-energy biocoenoses, pseudo-biocoenoses (gravity flow accumulations) and thanatocoenoses.
Warne, M.T. & Whatley, R.C. iFirst article. Description of Systenobythere gen. nov. (Ostracoda, C... more Warne, M.T. & Whatley, R.C. iFirst article. Description of Systenobythere gen. nov. (Ostracoda, Crustacea) from the late Miocene of southeastern Australia with comments on its problematical taxonomic and palaeoecological affinities. Alcheringa, 1–8. ISSN 0311-5518.A new ostracod genus and species, Systenobythere archboldi, is described from late Miocene open neritic strata of southeastern Australia. Specimens occur in argillaceous glauconitic sands deposited in offshore continental shelf settings that were periodically influenced by coastal upwelling. Systenobythere archboldi possesses an adductor muscle scar pattern typical of the Bythocytheridae, but has a pentodont hinge and sieve-type normal pore canals atypical of this family.本文描述了澳大利亚东南部中新世晚期开阔浅海地层中的介形虫的一个新属种Systenobythere archboldi。标本出现于泥质海绿石砂中。该沉积物沉积于受海岸上涌流影响的远岸陆架环境。Systenobythere archboldi具有典型的Bythocytheridae科的收缩肌痕, 但它的五齿铰及筛型垂直毛细管并不是该科的典型特征。
Warne, M.T., June 2012. Record of the deep marine Clinocythereis australis Ayress and Swanson, 19... more Warne, M.T., June 2012. Record of the deep marine Clinocythereis australis Ayress and Swanson, 1991 (Ostracoda) from the upper Miocene Tambo River Formation, Gippsland Basin, Australia: Palaeo-oceanographic and biostratigraphic implications. Alcheringa, 151–156. ISSN 0311-5518.Fossils of the deep marine ostracod, Clinocythereis australis Ayress & Swanson, 1991 occur within the Tambo River Formation, Gippsland Basin, southeastern Australia and record an approximately 6 Ma phase of late Miocene coastal ocean upwelling within this region. The presence of deep marine faunal elements within late Miocene Mitchellian strata is in contrast to the absence of such faunal elements in latest Miocene Cheltenhamian and younger marine strata of the Bass Strait hinterland. The absence of deep marine faunal elements in post-Mitchellian onshore strata is due to the Kosciusko Uplift, which transformed Bass Strait into a wholly shallow seaway placing adjacent coastal regions beyond the reach of ocean upwelling influences. Mark T. Warne [mwarne@deakin.edu.au], School of Life and Environmental Sciences, Deakin University (Burwood Campus), 221 Burwood Highway, Burwood, Victoria, 3125, Australia. Received 26.3.2011; revised 20.5.2011; accepted 30.5.2011.
Early to late Pliocene sedimentary strata present across the northern Bass Strait hinterland, sou... more Early to late Pliocene sedimentary strata present across the northern Bass Strait hinterland, southeastern Australia yield extensive fossil proxy data relevant to the interpretation of high sea level coastal palaeomorphology. Within the Pliocene Whalers Bluff Formation exposed in coastal cliffs near the township of Portland, Victoria, marine microfossil faunas delineate two broad cycles of deposition. Both these sedimentary cycles are bound below by unconformity surfaces. Within the lower sedimentary cycle, a basal stress-tolerant (low diversity) marginal marine microfossil fauna devoid of ostracods and suggestive of bottom-water hypoxia, is succeeded by a diverse shallow marine ostracod fauna dominated by stenohaline species indicative of a sheltered (but open) oceanic embayment. This lower sedimentary cycle has an early Pliocene (Zanclean) age. Equivalent shallow marine (e.g. coastal embayment) deposits occur broadly across the coastal hinterland of southeastern Australia—reflecting the generally higher global sea levels of this time. The upper cycle in the cliff exposures at Portland is late Pliocene (Piacenzian) in age. Equivalent deposits across the Bass Strait hinterland are restricted to former incised river valley settings. Euryhaline estuarine/coastal lagoon Ostracoda are present throughout the upper cycle in the Portland cliffs. These are associated with a low diversity microfauna at the base of the upper cycle and a high diversity microfauna towards the top of the cycle. Early Pliocene coastal marine deposits can be distinguished from late Pliocene coastal marine deposits across the northern Bass Strait hinterland on the basis of the presence or absence of certain open marine (‘stenohaline’) ostracod species.
Early Pliocene ostracod faunas of the Jemmys Point Formation, onshore Gippsland Basin, yield a ri... more Early Pliocene ostracod faunas of the Jemmys Point Formation, onshore Gippsland Basin, yield a rich and well-preserved marine ostracod fauna of mixed shallow marine and deep marine origins. The ostracod faunas evidence a marine continental shelf palaeoenvironment that, during the deposition of one stratigraphic interval, was influenced by a strong, persistent upwelling current. This upwelling current allowed the migration of deep-sea Ostracoda (Philoneptunus sp.) onto the continental shelf. The deeper marine aspect of this early Pliocene fauna, and of modern ostracod faunas from the Bass Strait region, evidence the adaptation of deep shelf taxonomic clades to shallow cool temperate shelf environments and highlights one unusual evolutionary mechanism that has contributed to modern Bass Strait shallow marine biodiversity. Four species are newly described: Neonesidea chapminuta sp. nov., Tasmanocypris salaputia sp. nov., Oculocytheropteron jemmyensis sp. nov., and Philoneptunus plutonis sp. nov.
The Lower Devonian (Emsian) Norton Gully Sandstone contains rich invertebrate fossil faunas inclu... more The Lower Devonian (Emsian) Norton Gully Sandstone contains rich invertebrate fossil faunas including ostracods. Seven ostracod taxa are recognized and illustrated herein: Bungonibeyrichia copelandi, Bungonibeyrichia wooriyallockensis, Bungonibeyrichia treslata sp. nov., Bungonibeyrichia australiae, Bairdiocypris sp., and two indeterminate genera. The ostracods are preserved in sandstone and mudstone as natural moulds. There are two distinct biofacies identified within the Norton Gully Sandstone: one dominated by ornate ostracods belonging to Bungonibeyrichia; and the other by smooth species of Bairdiocypris. We also conclude that most southeast Australian species previously placed in Velibeyrichia are more appropriately placed in Bungonibeyrichia on the basis of lobe morphology. Consequently, both these genera can be recognized as having discrete Silurian-Devonian palaeobiogeographical distributions, with Velibeyrichia spp. occurring in the shallow seas of Laurentia, while Bungonibeyrichia spp. was restricted to shallow seas around eastern Gondwana.
The uppermost Miocene Bookpurnong Formation within the Murray Basin of southeastern Australia ove... more The uppermost Miocene Bookpurnong Formation within the Murray Basin of southeastern Australia overlies a regionally extensive subaerial unconformity formed by relatively low late Miocene eustatic sea levels, and the initial phase of the Kosciuszko Uplift tectonic event. A diverse marine fossil ostracod fauna has been recovered from the Bookpurnong Formation, and is associated with a marine transgression that flooded inland regions of southeastern Australia to form a shallow epicontinental sea. Many of the Bookpurnong Formation ostracods represent immigrant taxa, with species such as Puriana lubbockiana, evidencing a subtropical range expansion of thermophilic warm water forms into southern mid latitudes. We attribute this to warm plumes from the East Australian Current, which would have impacted southeastern Australia at that time. In general, the Bookpurnong Formation ostracod assemblages indicate low to moderate energy shallow offshore palaeoenvironments subject to warm-temperate and subtropical conditions. One new genus and five new species are described: Fortistriginglymus gen. nov., Bradyleberis praecristatella sp. nov., Callistocythere bookpurnongensis sp. nov., Callistocythere mchenryi sp. nov., Callistocythere zigzaga sp. nov., and Parakeijia notoreticularis sp. nov.
The ‘Illaenus’ band of the Costerfield Siltstone in the Costerfield-Heathcote area contains pocke... more The ‘Illaenus’ band of the Costerfield Siltstone in the Costerfield-Heathcote area contains pockets of Silurian (lower Wenlock) deposits that contain a rich invertebrate fauna. Several assemblages from the ‘Illaenus’ band have been described and include ostracod species referable to 13 genera. These specimens were housed at the Australian Government Bureau of Mineral Resources in Canberra, which was damaged by fire in 1953. Of the documented ostracod specimens, only three remain, but are in a degraded state. We reinterpret this historically important material as representing the types of Ctenobolbina proxima and Kayatia prima.
Volcanic rocks occur in different types of sedimentary basins, especially those evolving from lit... more Volcanic rocks occur in different types of sedimentary basins, especially those evolving from lithospheric stretching. While volcanoes and other igneous rocks are widespread in the onshore Otway Basin, well-preserved volcanoes have not been documented in the offshore portion of the basin. Here, we analysed high-quality 2-D and 3-D seismic reflection datasets to investigate the origin and distribution of the enigmatic, kilometre-scale buried mound-shaped structures in the Prawn Platform, offshore Otway Basin. Detailed seismic characterisation enabled the identification of 19 mounds, ranging from ~90–400 m in height and 1.8–6 km in diameter. Relatively small (~0.2–11 km2) igneous sills are associated with these mounds. Based on their external geometries and internal seismic architectures, we interpret these mounds as dyke-fed shield volcanoes. Distinct seismic facies characterise the buried volcanoes, including the main volcanic eruption centre, tuff cone, and pyroclastic mass-wasting deposits. Interbedded extrusive and sedimentary rocks are mainly observed within volcanoes over 250 m high, and are associated with gullies along their flanks, indicating these volcanoes may have been subject to erosion. The volcanoes occur at three stratigraphic levels: late Eocene (~37 Ma), mid-Oligocene (~27–29 Ma), and early Miocene (~20 Ma), within the age of the Older Volcanics of the southern Australian margin. We propose that this newly discovered volcanism in the offshore Otway Basin was caused by edge-driven convection (similar mechanism to adjacent onshore volcanism), associated with the fast spreading rate of the Southern Ocean since the late Eocene (~40 Ma). The discovery of these buried volcanoes extends our understanding of magmatism in the Otway Basin, especially regarding the offshore extension of the Older Volcanics.
The Plio-Pleistocene Whalers Bluff Formation (WBF) of the offshore Otway Basin is composed of mix... more The Plio-Pleistocene Whalers Bluff Formation (WBF) of the offshore Otway Basin is composed of mixed siliciclastic- carbonate sediments. In seismic cross sections, this formation includes an interval that consists of higher amplitude seismic reflections that display alternating depressional ponds and raised ridges. This interval is shallowly buried and lies between 40 and 150 ms two-way traveltime below the present-day seafloor. In this study, we have used 2D and 3D seismic data sets in combination with the available shallow subsurface well logs to characterize the geomorphology and investigate the origin of these enigmatic features. The ponds are expressed as densely packed, circular to polygonal, and in some cases, hexagonal-shaped features in time slice maps, and they closely resemble previously documented honeycomb structures. In our study area, the honeycomb-like structures (HS) are comprised of large (200–800mdiameter range) depressed ponds that are separated by narrow (approximately 20m at the top) reticulate ridges. In total, these HS cover an area of 760 km2. Geospatial analysis shows that the ponds of HS, especially those in the northeast of the study area, are aligned along the northwest–southeast trend lines. There are several possible origins for the HS. The most probable mechanism is that the HS resulted from the bulk contraction of soft sediment, associated with shallow-burial diagenesis processes such as subaqueous dewatering of the fine-grained successions within the WBF. Interestingly, irregular furrows of various lengths on the seafloor correspond to the ridges of the HS, and we hypothesize that these furrows may have formed due to differential compaction of the underlying alternating ponds and ridges. Our results demonstrate the benefits of using seismic reflection data sets in combination with geospatial analysis to investigate the buried paleogeomorphologic features and their impact on the present-day seafloor physiography.
A continental shelf to upper continental slope ostracod fauna is documented from the late Cretace... more A continental shelf to upper continental slope ostracod fauna is documented from the late Cretaceous (late Turonian to Santonian) Belfast Mudstone in Voluta-1 of the Otway Basin, southeastern Australia. The fauna has palaeobiogeographical affinities with mid-late Cretaceous ostracod faunas of Western Australia, New Zealand, the Antarctic Peninsula and the Falklands Plateau. This distribution pattern probably reflects dispersal influenced by the opening of the Australo-Antarctic Gulf, and by clockwise gyre currents in the proto Southern Ocean. The presence of Philoneptunus sp. in this fauna suggests that the Australo-Antarctic Gulf was an important locus for deep sea colonization by Gondwanan neritic ostracod clades.
A new fossil paracypridine ostracod, Tasmanocypris lochardi sp.nov. is described from late Miocen... more A new fossil paracypridine ostracod, Tasmanocypris lochardi sp.nov. is described from late Miocene shallow marine strata of southeastern Australia. It has morphological features similar to a number of modern southern Australian and southwest African Tasmanocypris species, here termed the dartnalli-group. This species group was likely present in early Cenozoic temperate, shallow seas around Antarctica. The first appearance of Tasmanocypris lochardi in late Miocene marine strata of the Bass Strait hinterland of SE Australia, equates to a late Miocene (9–7 Ma) intensification and northward latitudinal shift of the Antarctic Circumpolar Current (ACC). Late Miocene occurrences of Tasmanocypris lochardi in southeast Australia were likely associated with temperate eastward flows of the ACC north of the Subantarctic Front. During the early Pliocene, the warm Zeehan Current (aka Leeuwin Current) replaced the ACC as the dominant easterly flowing current across Bass Strait, and this 4.4 Ma palaeoceanographical event correlates with the temporary, but widespread disappearance of T. lochardi from southeast Australian marine waters. However, the presence of refugia populations of T. lochardi along the east Australian continental shelf between 4.4 and 3.4 Ma, likely enabled the brief re establishment of T. lochardi in the east of Bass Strait during the late Pliocene (3.2–3.0 Ma). Tasmanocypris lochardi became permanently extinct in this region during the latest Pliocene to early Pleistocene (< 2.6 Ma), broadly correlating with the onset of the global Quaternary glaciation, and inception of the cold Bass Cascade winter current within Bass Strait.
Known occurrences of the ostracod genus Velibeyrichia are restricted to a number of Silurian to L... more Known occurrences of the ostracod genus Velibeyrichia are restricted to a number of Silurian to Lower Devonian geological strata in North America: the McKenzie Member of the Mifflintown Formation of Maryland and West Virginia; the Tonoloway Limestone of Maryland, West Virginia, Virginia and Pennsylvania; the Bloomsburg Formation of Maryland, Virginia and Pennsylvania; the Manlius Limestone of New York; and the Decker Limestone of New Jersey and New York. The genus includes six species: V. moodeyi (type species), V. mesleri, V. paucigranulosa, V. reticulosaccula, V. tonolowayensis and V. tricornia. The diagnostic combination of characters for this genus are: distinct deflection of the velum where it crosses the crumina in heteromorphs (adult female specimens), dorsal nodes on lobes L1 and L3, sexual dimorphism of the velum, and in tecnomorph specimens, either a shallow sulcus on lobe L3 or a zygal ridge (in adult tecnomorph specimens) extending from lobe L2 to lobe L3. The presence of one or the other of the latter two characters defines two distinct species groups.
Alcheringa: An Australasian Journal of Palaeontology, 2017
The abundant and diverse beyrichioid ostracod faunas preserved in Silurian and Devonian silisicla... more The abundant and diverse beyrichioid ostracod faunas preserved in Silurian and Devonian silisiclastic strata of the Lachlan Orogen in southeastern
Australia include specimens of the genus Bungonibeyrichia. Bungonibeyrichia copelandi sp. nov. is proposed for the fossil material, originally
misidentified at species level, on which the description of this genus was based. The new species is nominated as the type species for Bungonibeyrichia
in accordance with Article 70.3 of the International Code of Zoological Nomenclature. Bungonibeyrichia is distinguished from other
beyrichioid genera on the basis of a distinctive combination of lobe, velum and crumina features.
Three closely allied shallow marine taxa, Neohornibrookella sorrentae (Chapman and Crespin), Neoh... more Three closely allied shallow marine taxa, Neohornibrookella sorrentae (Chapman and Crespin), Neohornibrookella glyphica (Neil), and Neohornibrookella nepeani sp. nov. are recorded from latest early Miocene to late Pliocene strata in southeastern Australia. These taxa, together with Neohornibrookella quadranodosa (Holden) from the Miocene of Midway Island (Northwestern Hawaiian Islands), form a morphologically distinct group of relatively large species (the sorrentae-group) within the genus Neohornibrookella Jellinek. Latitudinal expansion of the subtropical and warm-temperate climatic belts together with the influence of warm western boundary surface currents associated with the North and South Pacific gyres, are likely to have played key roles in the Miocene dispersal of this species group. Species of the sorrentae-group first migrated south from equatorial west Pacific regions into southeastern Australia during the early Miocene, under the influence of the East Australian Current. During three time intervals (i) latest early Miocene, (ii) latest late Miocene and (iii) earliest late Pliocene, forceful pulses of the East Australian Current played a significant role in propelling the widespread distribution of thermophilic Neohornibrookella species across southeast Australian shallow marine realms. During intervening middle and late Miocene times, Neohornibrookella species are only sporadically present across the Bass Strait region of southeast Australia, indicating a weaker East Australian Current influence and the cooling influence of coastal upwelling. During the mid early Pliocene Neohornibrookella species disappeared from the western Bass Strait region, suggesting the complete exclusion of East Australian Current waters from this region. This was probably due to the counteracting influence of the eastward flowing Zeehan Current (extension of the Leeuwin Current) impinging on the western Bass Strait region. This mid early Pliocene palaeobiogeographical partition in Bass Strait, defined by the distribution of sorrentae-group species, is here termed the Bassian Gateway. The two species, N. sorrentae and N. glyphica, occur concurrently during the mid Miocene in southeast Australia, but are associated with different lithofacies. It is hypothesised that there is a heterochronic evolutionary relationship expressed in the ornament of these two species. The thaerocytherid genera Neohornibrookella Jellinek, Tenedocythere Sissingh and Bosasella Bonaduce are here included in the new ostracod subfamily Tenedocytherinae.
(URL: http://www.sciencedirect.com/science/article/pii/S0377839816300251)
Alcheringa: An Australasian Journal of Palaeontology, 2014
ABSTRACT The Humevale Siltstone (late Silurian to Early Devonian, Gorstian to Pragian) and Woori ... more ABSTRACT The Humevale Siltstone (late Silurian to Early Devonian, Gorstian to Pragian) and Woori Yallock Formation (Early Devonian, Emsian) of central Victoria, Australia, contain rich invertebrate fossil faunas including Ostracoda. Eight ostracod taxa are recognized and illustrated herein: Velibeyrichia wooriyallockensis (Chapman), Velibeyrichia (s.l.) australiae (Chapman), Velibeyrichia sp. 1, Velibeyrichia sp. 2, Beyrichia? ligatura (Chapman), Ulrichia sp., Euglyphella sp. and Strepulites sp. The ostracods are preserved in siltstones and mudstones as natural moulds. Ostracod assemblages are mainly shallow marine and likely include moderate- to low-energy biocoenoses, pseudo-biocoenoses (gravity flow accumulations) and thanatocoenoses.
Warne, M.T. & Whatley, R.C. iFirst article. Description of Systenobythere gen. nov. (Ostracoda, C... more Warne, M.T. & Whatley, R.C. iFirst article. Description of Systenobythere gen. nov. (Ostracoda, Crustacea) from the late Miocene of southeastern Australia with comments on its problematical taxonomic and palaeoecological affinities. Alcheringa, 1–8. ISSN 0311-5518.A new ostracod genus and species, Systenobythere archboldi, is described from late Miocene open neritic strata of southeastern Australia. Specimens occur in argillaceous glauconitic sands deposited in offshore continental shelf settings that were periodically influenced by coastal upwelling. Systenobythere archboldi possesses an adductor muscle scar pattern typical of the Bythocytheridae, but has a pentodont hinge and sieve-type normal pore canals atypical of this family.本文描述了澳大利亚东南部中新世晚期开阔浅海地层中的介形虫的一个新属种Systenobythere archboldi。标本出现于泥质海绿石砂中。该沉积物沉积于受海岸上涌流影响的远岸陆架环境。Systenobythere archboldi具有典型的Bythocytheridae科的收缩肌痕, 但它的五齿铰及筛型垂直毛细管并不是该科的典型特征。
Warne, M.T., June 2012. Record of the deep marine Clinocythereis australis Ayress and Swanson, 19... more Warne, M.T., June 2012. Record of the deep marine Clinocythereis australis Ayress and Swanson, 1991 (Ostracoda) from the upper Miocene Tambo River Formation, Gippsland Basin, Australia: Palaeo-oceanographic and biostratigraphic implications. Alcheringa, 151–156. ISSN 0311-5518.Fossils of the deep marine ostracod, Clinocythereis australis Ayress & Swanson, 1991 occur within the Tambo River Formation, Gippsland Basin, southeastern Australia and record an approximately 6 Ma phase of late Miocene coastal ocean upwelling within this region. The presence of deep marine faunal elements within late Miocene Mitchellian strata is in contrast to the absence of such faunal elements in latest Miocene Cheltenhamian and younger marine strata of the Bass Strait hinterland. The absence of deep marine faunal elements in post-Mitchellian onshore strata is due to the Kosciusko Uplift, which transformed Bass Strait into a wholly shallow seaway placing adjacent coastal regions beyond the reach of ocean upwelling influences. Mark T. Warne [mwarne@deakin.edu.au], School of Life and Environmental Sciences, Deakin University (Burwood Campus), 221 Burwood Highway, Burwood, Victoria, 3125, Australia. Received 26.3.2011; revised 20.5.2011; accepted 30.5.2011.
Early to late Pliocene sedimentary strata present across the northern Bass Strait hinterland, sou... more Early to late Pliocene sedimentary strata present across the northern Bass Strait hinterland, southeastern Australia yield extensive fossil proxy data relevant to the interpretation of high sea level coastal palaeomorphology. Within the Pliocene Whalers Bluff Formation exposed in coastal cliffs near the township of Portland, Victoria, marine microfossil faunas delineate two broad cycles of deposition. Both these sedimentary cycles are bound below by unconformity surfaces. Within the lower sedimentary cycle, a basal stress-tolerant (low diversity) marginal marine microfossil fauna devoid of ostracods and suggestive of bottom-water hypoxia, is succeeded by a diverse shallow marine ostracod fauna dominated by stenohaline species indicative of a sheltered (but open) oceanic embayment. This lower sedimentary cycle has an early Pliocene (Zanclean) age. Equivalent shallow marine (e.g. coastal embayment) deposits occur broadly across the coastal hinterland of southeastern Australia—reflecting the generally higher global sea levels of this time. The upper cycle in the cliff exposures at Portland is late Pliocene (Piacenzian) in age. Equivalent deposits across the Bass Strait hinterland are restricted to former incised river valley settings. Euryhaline estuarine/coastal lagoon Ostracoda are present throughout the upper cycle in the Portland cliffs. These are associated with a low diversity microfauna at the base of the upper cycle and a high diversity microfauna towards the top of the cycle. Early Pliocene coastal marine deposits can be distinguished from late Pliocene coastal marine deposits across the northern Bass Strait hinterland on the basis of the presence or absence of certain open marine (‘stenohaline’) ostracod species.
Various types of igneous rocks have been frequently encountered during hydrocarbon exploration of... more Various types of igneous rocks have been frequently encountered during hydrocarbon exploration of sedimentary basins along rifted passive margins, and their impacts on the hydrocarbon maturation and migration processes are diverse. Buried volcanoes generally act as migration pathways, whilst magma intrusions are often associated with source rock maturation. Importantly, the high acoustic velocity and density of igneous intrusions, introduces imaging problems. Therefore, understanding the igneous plumbing styles within the sediments, remained crucial for hydrocarbon exploration for frontier basins. Combining the seismic reflection surveys with magnetic datasets, in this study we identified six intrusive sills, seven lava flows and feeder dykes beneath them. Thirty cones to trapezium-shaped and twenty-seven dome to eye-shaped mounds are also identified and based on their magnetic and seismic geomorphic attributes, are interested as monogenetic volcanoes and hydrothermal vents, respectively. The igneous complexes were emplaced between mid-Eocene to mid-Miocene, while the hydrothermal vents are mainly of mid Eocene. Most of the volcanic/hydrothermal vents are linked to the underlying rift related faults via vertical zones of disruption, which are interpreted as feeder dykes or hydrothermal fluid pipes, respectively. The scattered distribution of sills and dyke-dominated volcanoes of this study, contrasts to most of the recent studies that highlight the importance of the lateral magma transportation in sedimentary basins. Our comparison with the neighbouring Bight Basin, suggests that he thin crust but relatively thick sediment layers of the Bight Basin, facilitated the lateral transportation of magma and promoted sill-fed volcanism, while the magma ascending through thick crust but relatively thin sediment layers of the Otway Basin, produced sufficient magma pressure and promoted the predominantly dyke-fed igneous plumbing system. This work highlights the critical role of basin structures, such as continental crust, sedimentary thickness, and faults, in controlling the distribution, morphology and style of post-rift igneous plumbing processes in magma-poor margins.
18th ISO Abstract book in Cypris International Ostracoda Newsletter 35 supplement, p.60. Publisher: Förderverein für die International Research Group on Ostracoda e. V. Zülpicher Straße 49A 50674 Cologne Germany, 2017
18th ISO Abstract book in Cypris International Ostracoda Newsletter 35 supplement, p.74. Publisher: Förderverein für die International Research Group on Ostracoda e. V. Zülpicher Straße 49A 50674 Cologne Germany, 2017
The Hopkins and Glenelg estuaries occur along the western coastal plains of Victoria, except for ... more The Hopkins and Glenelg estuaries occur along the western coastal plains of Victoria, except for a small section of the latter which extends into south-east South Australia. A study of sedimentation rates, sediment reworking events and palaeoenvironments evident within Pb210 dated sediment cores from these estuaries has revealed three phases of sedimentation between 1977 and 2006.
These are: • Phase 1 (1977–1986). High sedimentation rates with extensive evidence of subtidal sediment reworking and disruption except in protected backwaters. • Phase 2 (1987–1996). High sedimentation rates with no evidence of bottom sediment reworking by water currents in subtidal settings. • Phase 3 (1997–2006). Low sedimentation rates (some exceptions in upper gorge regions of Glenelg Estuary) with no evidence of bottom sediment reworking by water currents in subtidal settings.
These sedimentation phases correlate with river discharge trends and decadal-scale regional climate (rainfall) variability. Thus, from sediment core analyses of the Hopkins and Glenelg estuaries, a general temporal estuarine sedimentation model can be constructed for the microtidal salt-wedge estuaries of south-west Victoria for the period 1977–2006. This model has three components.
• Major flood events (early 1980s). Significant flushing of sediment from estuarine settings. Slugs of new and disrupted sediment deposited. Extensive reworking and widespread scouring of subtidal bottom sediments. Probable net loss of bottom sediment in subtidal settings. • ‘Normal’ period of seasonal high and low flows (1987–1996). High sedimentation rates in subtidal settings. Minimal reworking or disruption of subtidal bottom sediments. Moderate net gain of bottom sediment in subtidal settings. • Drought period seasonal ‘high’ and low flows (1997–2006). Low sedimentation rates in subtidal settings. No reworking of subtidal bottom sediments. Small net gain of bottom sediment in subtidal settings.
A consequence of the direct relationship between river discharge and estuarine sedimentation is that shifts in climate variability over decadal and multi-decadal time scales are likely to have pronounced impacts on sediment distribution and mobility within estuarine settings in SE Australia.
Geological Society of Australia Abstracts, v. 37, p. 22, 1994
Cyclic sedimentation in the Carpentaria Basin is outlined by assessing changes in sediment compos... more Cyclic sedimentation in the Carpentaria Basin is outlined by assessing changes in sediment composition as well as microfauna and palynological assemblages and demonstrates that deposition took place in a variety of marine environments characterised by changing sea-floor conditions.
A new leptocytherid genus Vandiemencythere is described. The genus includes four species two of w... more A new leptocytherid genus Vandiemencythere is described. The genus includes four species two of which are described as new, and the remaining two are left open nomenclatures. V. Gunyoungenesis, the type species, is known from the early Middle Miocene of Victoria, southeastern Australia. V. Phleboides is endemic to New Zealand and ranges from Late Eocene to Late Miocene. Vandiemencythere sp. 1 is recorded on these eastern Australian shelf in the Pliocene. Vandiemencythere sp. 2 is recorded from the Recent of the Coral Sea, S.W. Pacific Ocean.
Early Pliocene ostracod faunas of the Jemmys Point Formation, onshore Gippsland Basin, yield a ri... more Early Pliocene ostracod faunas of the Jemmys Point Formation, onshore Gippsland Basin, yield a rich and well-preserved marine ostracod fauna of mixed shallow marine and deep marine origins. The ostracod faunas evidence a marine continental shelf palaeoenvironment that, during the deposition of one stratigraphic interval, was influenced by a strong, persistent upwelling current. This upwelling current allowed the migration of deep-sea Ostracoda (Philoneptunus sp.) onto the continental shelf. The deeper marine aspect of this early Pliocene fauna, and of modern ostracod faunas from the Bass Strait region, evidence the adaptation of deep shelf taxonomic clades to shallow cool temperate shelf environments and highlights one unusual evolutionary mechanism that has contributed to modern Bass Strait shallow marine biodiversity. Four species are newly described: Neonesidea chapminuta sp. nov., Tasmanocypris salaputia sp. nov., Oculocytheropteron jemmyensis sp. nov., and Philoneptunus plutonis sp. nov.
Magmatic rocks are frequently encountered during hydrocarbon exploration in rift-related sediment... more Magmatic rocks are frequently encountered during hydrocarbon exploration in rift-related sedimentary basins. As magmatic rocks may contribute both positively and negatively to the hydrocarbon systems, their spatio-temporal distribution and structural elements are crucial for exploration in frontier basins. With the proliferation and increased density of seismic reflection data, various subsurface magmatic features can be discriminated and illuminated via conventional interpretation approaches, such as attribute extraction, opacity rendering or geo-body extraction. However, these manual interpretation techniques are labor-intensive, subject to interpreter bias and often bottleneck with respect to time data delivery. A supervised machine learning approach could efficiently resolve these issues by amalgamating suitable seismic attributes, such as energy, reflection strength, texture, and similarity, and automatically delineating these magmatic features in 3D seismic reflection data. Ou...
Alcheringa: An Australasian Journal of Palaeontology
The ‘Illaenus’ band of the Costerfield Siltstone in the Costerfield-Heathcote area contains pocke... more The ‘Illaenus’ band of the Costerfield Siltstone in the Costerfield-Heathcote area contains pockets of Silurian (lower Wenlock) deposits that contain a rich invertebrate fauna. Several assemblages from the ‘Illaenus’ band have been described and include ostracod species referable to 13 genera. These specimens were housed at the Australian Government Bureau of Mineral Resources in Canberra, which was damaged by fire in 1953. Of the documented ostracod specimens, only three remain, but are in a degraded state. We reinterpret this historically important material as representing the types of Ctenobolbina proxima and Kayatia prima.
The Hopkins and Glenelg estuaries occur along the western coastal plains of Victoria, except for ... more The Hopkins and Glenelg estuaries occur along the western coastal plains of Victoria, except for a small section of the latter which extends into south-east South Australia. A study of sedimentation rates, sediment reworking events and palaeoenvironments evident within Pb210 dated sediment cores from these estuaries has revealed three phases of sedimentation between 1977 and 2006. These are: • Phase 1 (1977–1986). High sedimentation rates with extensive evidence of subtidal sediment reworking and disruption except in protected backwaters. • Phase 2 (1987–1996). High sedimentation rates with no evidence of bottom sediment reworking by water currents in subtidal settings. • Phase 3 (1997–2006). Low sedimentation rates (some exceptions in upper gorge regions of Glenelg Estuary) with no evidence of bottom sediment reworking by water currents in subtidal settings. These sedimentation phases correlate with river discharge trends and decadal-scale regional climate (rainfall) variability. Thus, from sediment core analyses of the Hopkins and Glenelg estuaries, a general temporal estuarine sedimentation model can be constructed for the microtidal salt-wedge estuaries of south-west Victoria for the period 1977–2006. This model has three components. • Major flood events (early 1980s). Significant flushing of sediment from estuarine settings. Slugs of new and disrupted sediment deposited. Extensive reworking and widespread scouring of subtidal bottom sediments. Probable net loss of bottom sediment in subtidal settings. • ‘Normal’ period of seasonal high and low flows (1987–1996). High sedimentation rates in subtidal settings. Minimal reworking or disruption of subtidal bottom sediments. Moderate net gain of bottom sediment in subtidal settings. • Drought period seasonal ‘high’ and low flows (1997–2006). Low sedimentation rates in subtidal settings. No reworking of subtidal bottom sediments. Small net gain of bottom sediment in subtidal settings. A consequence of the direct relationship between river discharge and estuarine sedimentation is that shifts in climate variability over decadal and multi-decadal time scales are likely to have pronounced impacts on sediment distribution and mobility within estuarine settings in SE Australia.
Abstract Spatially and volumetrically extensive igneous rocks are exposed onshore in southeastern... more Abstract Spatially and volumetrically extensive igneous rocks are exposed onshore in southeastern Australia and provide important information about the Cenozoic evolution of the region. However, the morphology and distribution of igneous rocks are still not well constrained in the ∼70 km wide continental shelf of the central Otway Basin. Within this region, we present seismo-geomorphological characteristics of 30 volcanoes and 27 hydrothermal vents, as well as several lava flows and magmatic sills, based on 2D and 3D seismic reflection data. Hydrothermal vents formed mainly during the mid-Eocene, while igneous complexes developed between the mid-Eocene to late Miocene, both post-dating continental break-up in the basin. The distribution and morphology of igneous rocks and hydrothermal vents is influenced by rift-related faults, as most of these features are linked to the underlying faults by near-vertical zones of disruption and are elongated in an NW-SE direction that parallels the primary fault trend. Magma for volcanoes and heat sources for hydrothermal vents within the study area are likely supplied by deep-sourced dykes, as magmatic sills only have a scattered distribution in this region. This implies a dyke-dominated plumbing system for magmatism in the Otway Basin. In comparison, the nearby Bight Basin, which has a thin basement but a relatively thick sedimentary sequence, displays magma propogation more prone to forming igneous sills. There are many lithological and tectonic similarities between the Otway and Bight basins; thus, we propose that a relatively thin sedimentary sequence over a thick basement in the Otway Basin produced sufficient magma pressure for a predominantly dyke-dictated igneous plumbing system. This work highlights the critical role of basin structures, such as the thickness of basement and overlying strata, in the control of igneous plumbing styles and the distribution of post-rift igneous complexes along magma-poor continental margins. Our work, therefore, aids the estimation of different magmatic components within the sedimentary basins and facilitates the understanding of their diverse impacts on the exploration of frontier basins. This result also provides some constraints on the prediction of possible future eruption centres within active volcanic fields.
Early Devonian charophytes are reported from Australia (Buchan, Victoria) and Europe (Landeyran, ... more Early Devonian charophytes are reported from Australia (Buchan, Victoria) and Europe (Landeyran, southern France): Moellerina australica n. sp. Feist and Pinnoputamen occitanicum n. sp. Feist. Sedimentological data and associated faunas from these localities accord with both species having inhabited lacustrine or estuarine environments. A critical review of Devonian biotopes confirms that, as with present day species, Mid Palaeozoic charophytes could not have lived in open marine habitats. Originating in Baltica during the Silurian, charophytes appeared in Gondwana in the earliest Devonian.
southeastern Australia for the new species A . johannae (type species), A . robusta, and A . mioc... more southeastern Australia for the new species A . johannae (type species), A . robusta, and A . miocenica, and the new species and subspecies A . ornithopetrae ornithopetrae and A. ornithopetrae willungae. Our new genus is compared with specimens of Alatacythere from the Gulf Coast o f the United States and with Pterygocythereis from the Atlantic/Mediterranean. Its stratigraphic usefulness is indicated. The Tertiary Ostracoda of southeastern Australia re main poorly known (McKenzie 1974) although recent work in the Miocene of Victoria suggests that the situa tion is about to ameliorate (McKenzie & Neil 1983, Whatley & Downing 1983, McKenzie & Peypouquet 1984). During a broader study of several Miocene se quences in Victoria, one of us (M .T.W .) came across a new taxon with apparent affinities to the genus Alatacythere from the Gulf Coast Tertiary of the United States. Discussion with the senior author led to the con sensus that this species represented a new generic category (n. g...
The Plio-Pleistocene Whalers Bluff Formation (WBF) of the offshore Otway Basin is composed of mix... more The Plio-Pleistocene Whalers Bluff Formation (WBF) of the offshore Otway Basin is composed of mixed siliciclastic-carbonate sediments. In seismic cross sections, this formation includes an interval that consists of higher amplitude seismic reflections that display alternating depressional ponds and raised ridges. This interval is shallowly buried and lies between 40 and 150 ms two-way traveltime below the present-day seafloor. In this study, we have used 2D and 3D seismic data sets in combination with the available shallow subsurface well logs to characterize the geomorphology and investigate the origin of these enigmatic features. The ponds are expressed as densely packed, circular to polygonal, and in some cases, hexagonal-shaped features in time-slice maps, and they closely resemble previously documented honeycomb structures. In our study area, the honeycomb-like structures (HS) are comprised of large (200–800 m diameter range) depressed ponds that are separated by narrow (approx...
Abstract Volcanic rocks occur in different types of sedimentary basins, especially those evolving... more Abstract Volcanic rocks occur in different types of sedimentary basins, especially those evolving from lithospheric stretching. While volcanoes and other igneous rocks are widespread in the onshore Otway Basin, well-preserved volcanoes have not been documented in the offshore portion of the basin. Here, we analysed high-quality 2-D and 3-D seismic reflection datasets to investigate the origin and distribution of the enigmatic, kilometre-scale buried mound-shaped structures in the Prawn Platform, offshore Otway Basin. Detailed seismic characterisation enabled the identification of 19 mounds, ranging from ∼90–400 m in height and 1.8–6 km in diameter. Relatively small (∼0.2–11 km2) igneous sills are associated with these mounds. Based on their external geometries and internal seismic architectures, we interpret these mounds as dyke-fed shield volcanoes. Distinct seismic facies characterise the buried volcanoes, including the main volcanic eruption centre, tuff cone, and pyroclastic mass-wasting deposits. Interbedded extrusive and sedimentary rocks are mainly observed within volcanoes over 250 m high, and are associated with gullies along their flanks, indicating these volcanoes may have been subject to erosion. The volcanoes occur at three stratigraphic levels: late Eocene (∼37 Ma), mid-Oligocene (∼27–29 Ma), and early Miocene (∼20 Ma), within the age of the Older Volcanics of the southern Australian margin. We propose that this newly discovered volcanism in the offshore Otway Basin was caused by edge-driven convection (similar mechanism to adjacent onshore volcanism), associated with the fast spreading rate of the Southern Ocean since the late Eocene (∼40 Ma). The discovery of these buried volcanoes extends our understanding of magmatism in the Otway Basin, especially regarding the offshore extension of the Older Volcanics.
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These specimens were housed at the Australian Government Bureau of Mineral Resources in Canberra, which was damaged by fire in 1953. Of the documented ostracod specimens, only three remain, but are in a degraded state. We reinterpret this historically important material as representing
the types of Ctenobolbina proxima and Kayatia prima.
buried and lies between 40 and 150 ms two-way traveltime below the present-day seafloor. In this study, we have used 2D and 3D seismic data sets in combination with the available shallow subsurface well logs to characterize the geomorphology and investigate the origin of these enigmatic features. The ponds are expressed as densely packed, circular to polygonal, and in some cases, hexagonal-shaped features in time slice maps, and they closely resemble previously documented honeycomb structures. In our study area, the honeycomb-like structures (HS) are comprised of large (200–800mdiameter range) depressed ponds that are separated by narrow (approximately 20m at the top) reticulate ridges. In total, these HS cover an area of 760 km2. Geospatial analysis shows that the ponds of HS, especially those in the northeast of the study area, are aligned along the northwest–southeast trend lines. There are several possible origins for the HS. The most probable mechanism is that the HS resulted from the bulk contraction of soft sediment, associated with shallow-burial diagenesis processes such as subaqueous dewatering of the fine-grained successions within the WBF. Interestingly, irregular furrows of various lengths on the seafloor correspond to the ridges of the HS, and we hypothesize that these furrows may have formed due to differential compaction of the underlying alternating ponds and ridges. Our results demonstrate the benefits of using seismic reflection data sets in combination with geospatial analysis to investigate the buried paleogeomorphologic features and their impact on the present-day seafloor physiography.
Australia include specimens of the genus Bungonibeyrichia. Bungonibeyrichia copelandi sp. nov. is proposed for the fossil material, originally
misidentified at species level, on which the description of this genus was based. The new species is nominated as the type species for Bungonibeyrichia
in accordance with Article 70.3 of the International Code of Zoological Nomenclature. Bungonibeyrichia is distinguished from other
beyrichioid genera on the basis of a distinctive combination of lobe, velum and crumina features.
(URL: http://www.sciencedirect.com/science/article/pii/S0377839816300251)
These specimens were housed at the Australian Government Bureau of Mineral Resources in Canberra, which was damaged by fire in 1953. Of the documented ostracod specimens, only three remain, but are in a degraded state. We reinterpret this historically important material as representing
the types of Ctenobolbina proxima and Kayatia prima.
buried and lies between 40 and 150 ms two-way traveltime below the present-day seafloor. In this study, we have used 2D and 3D seismic data sets in combination with the available shallow subsurface well logs to characterize the geomorphology and investigate the origin of these enigmatic features. The ponds are expressed as densely packed, circular to polygonal, and in some cases, hexagonal-shaped features in time slice maps, and they closely resemble previously documented honeycomb structures. In our study area, the honeycomb-like structures (HS) are comprised of large (200–800mdiameter range) depressed ponds that are separated by narrow (approximately 20m at the top) reticulate ridges. In total, these HS cover an area of 760 km2. Geospatial analysis shows that the ponds of HS, especially those in the northeast of the study area, are aligned along the northwest–southeast trend lines. There are several possible origins for the HS. The most probable mechanism is that the HS resulted from the bulk contraction of soft sediment, associated with shallow-burial diagenesis processes such as subaqueous dewatering of the fine-grained successions within the WBF. Interestingly, irregular furrows of various lengths on the seafloor correspond to the ridges of the HS, and we hypothesize that these furrows may have formed due to differential compaction of the underlying alternating ponds and ridges. Our results demonstrate the benefits of using seismic reflection data sets in combination with geospatial analysis to investigate the buried paleogeomorphologic features and their impact on the present-day seafloor physiography.
Australia include specimens of the genus Bungonibeyrichia. Bungonibeyrichia copelandi sp. nov. is proposed for the fossil material, originally
misidentified at species level, on which the description of this genus was based. The new species is nominated as the type species for Bungonibeyrichia
in accordance with Article 70.3 of the International Code of Zoological Nomenclature. Bungonibeyrichia is distinguished from other
beyrichioid genera on the basis of a distinctive combination of lobe, velum and crumina features.
(URL: http://www.sciencedirect.com/science/article/pii/S0377839816300251)
These are:
• Phase 1 (1977–1986). High sedimentation rates with extensive evidence of subtidal sediment reworking and disruption except in protected backwaters.
• Phase 2 (1987–1996). High sedimentation rates with no evidence of bottom sediment reworking by water currents in subtidal settings.
• Phase 3 (1997–2006). Low sedimentation rates (some exceptions in upper gorge regions of Glenelg Estuary) with no evidence of bottom sediment reworking by water currents in subtidal settings.
These sedimentation phases correlate with river discharge trends and decadal-scale regional climate (rainfall) variability. Thus, from sediment core analyses of the Hopkins and Glenelg estuaries, a general temporal estuarine sedimentation model can be constructed for the microtidal salt-wedge estuaries of south-west Victoria for the period 1977–2006. This model has three components.
• Major flood events (early 1980s). Significant flushing of sediment from estuarine settings. Slugs of new and disrupted sediment deposited. Extensive reworking and widespread scouring of subtidal bottom sediments. Probable net loss of bottom sediment in subtidal settings.
• ‘Normal’ period of seasonal high and low flows (1987–1996). High sedimentation rates in subtidal settings. Minimal reworking or disruption of subtidal bottom sediments. Moderate net gain of bottom sediment in subtidal settings.
• Drought period seasonal ‘high’ and low flows (1997–2006). Low sedimentation rates in subtidal settings. No reworking of subtidal bottom sediments. Small net gain of bottom sediment in subtidal settings.
A consequence of the direct relationship between river discharge and estuarine sedimentation is that shifts in climate variability over decadal and multi-decadal time scales are likely to have pronounced impacts on sediment distribution and mobility within estuarine settings in SE Australia.