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Articles 1 - 10 of 10
Full-Text Articles in Medicine and Health Sciences
Quaternary Calcarenite Stratigraphy On Lord Howe Island, Southwestern Pacific Ocean And The Record Of Coastal Carbonate Deposition, Brendan Brooke, Colin Woodroffe, Colin Murray-Wallace, H Heijnis, Brian Jones
Quaternary Calcarenite Stratigraphy On Lord Howe Island, Southwestern Pacific Ocean And The Record Of Coastal Carbonate Deposition, Brendan Brooke, Colin Woodroffe, Colin Murray-Wallace, H Heijnis, Brian Jones
B. G. Jones
Lord Howe Island is a small, mid-ocean volcanic and carbonate island in the southwestern Pacific Ocean. Skeletal carbonate eolianite and beach calcarenite on the island are divisible into two formations based on lithostratigraphy. The Searles Point Formation comprises eolianite units bounded by clay-rich paleosols. Pore-filling sparite and microsparite are the dominant cements in these eolianite units, and recrystallised grains are common. Outcrops exhibit karst features such as dolines, caves and subaerially exposed relict speleothems. The Neds Beach Formation overlies the Searles Point Formation and consists of dune and beach units bounded by weakly developed fossil soil horizons. These younger deposits …
Thermoluminescence Ages For A Reworked Coastal Barrier, Southeastern Vietnam: A Preliminary Report, Colin Murray-Wallace, Brian Jones, Tran Nghi, David Price, Vu Vinh, Trinh Tinh, Gerald Nanson
Thermoluminescence Ages For A Reworked Coastal Barrier, Southeastern Vietnam: A Preliminary Report, Colin Murray-Wallace, Brian Jones, Tran Nghi, David Price, Vu Vinh, Trinh Tinh, Gerald Nanson
B. G. Jones
Thermoluminescence dating of quartz sand (90-125 μm) from the coastal barrier successions between Phan Thiet and Tuy Phong, southeastern Vietnam, reveals that a substantial component was deposited during the last interglacial sensu lato (Oxygen Isotope Stage 5) between 108 and 85 ka. The barrier successions have subsequently, in places, experienced multiple phases of aeolian reworking during the last glacial cycle, and in particular between 62 and 19 ka, possibly related to reduced vegetation cover and landscape instability caused by climatic change. The difficulties of applying the thermoluminescence (TL) method in areas of intense tropical weathering are also examined.
Geochemical Comparisons Between Estuaries With Non-Industrialised And Industrialised Catchments: The Huon And Derwent River Estuaries, Tasmania, Brian Jones, Bryan Chenhall, F Debretsion, Adrian Hutton
Geochemical Comparisons Between Estuaries With Non-Industrialised And Industrialised Catchments: The Huon And Derwent River Estuaries, Tasmania, Brian Jones, Bryan Chenhall, F Debretsion, Adrian Hutton
B. G. Jones
The adjacent Huon and Derwent estuaries in Tasmania have similar climatic and physical characteristics, and provide a good comparison between relatively uncontaminated and industrially polluted estuaries, respectively. Representative samples were collected from both estuaries and analysed for grainsize and trace‐element content (using X‐ray fluorescence and neutron activation analyses). The Huon estuary drains a predominantly forested and agricultural catchment and contains low (baseline) concentrations of trace elements, including lead, zinc and copper. In contrast, the Derwent estuary has a geologically similar yet larger catchment and it passes through an industrialised area in the midestuarine reach. A zinc refinery has, in the …
Geochemical Consequences Of The Permian-Triassic Mass Extinction In A Non-Marine Succession, Sydney Basin, Australia, M Williams, B Jones, P Carr
Geochemical Consequences Of The Permian-Triassic Mass Extinction In A Non-Marine Succession, Sydney Basin, Australia, M Williams, B Jones, P Carr
B. G. Jones
The identification of the Permian–Triassic boundary (PTB) and Permian–Triassic mass extinction event (PTME) in eastern Australia is based primarily on palynological and plant fossil evidence with limited δ13Corg data from the northern part of the Sydney Basin. Consequently, the PTB in the Sydney Basin has been placed at the top of the last Permian coal measures. Here we report carbon and nitrogen isotopic data, together with major element, trace element and mineralogical data, for a continuous non‐marine Permian–Triassic (P–Tr) section from the southern Sydney Basin. The PTME is identified by a negative shift in δ13Corg of ~ 3.8‰ occurring approximately …
The Influence Of Palaeoenvironment And Lava Flux On The Emplacement Of Submarine, Near-Shore Late Permian Basalt Lavas, Sydney Basin (Australia), Paul Carr, Brian Jones
The Influence Of Palaeoenvironment And Lava Flux On The Emplacement Of Submarine, Near-Shore Late Permian Basalt Lavas, Sydney Basin (Australia), Paul Carr, Brian Jones
B. G. Jones
Lava flux and a low palaeoslope were the critical factors in determining the development of different facies in the Late Permian Blow Hole flow, which comprises a series of shoshonitic basalt lavas and associated volcaniclastic detritus in the southern Sydney Basin of eastern Australia. The unit consists of a lower lobe and sheet facies, a middle tube and breccia facies, and an upper columnar-jointed facies. Close similarities in petrography and geochemistry between the basalt lavas from the three facies suggest similar viscosities at similar temperatures. Sedimentological and palaeontological evidence from the sedimentary units immediately below the Blow Hole flow suggests …
Aspartic Acid Racemisation Dating Of Mid-Holocene To Recent Estuarine Sedimentation In New South Wales, Australia: A Pilot Study, C Sloss, C Murray-Wallace, B Jones, T Wallin
Aspartic Acid Racemisation Dating Of Mid-Holocene To Recent Estuarine Sedimentation In New South Wales, Australia: A Pilot Study, C Sloss, C Murray-Wallace, B Jones, T Wallin
B. G. Jones
The degree of aspartic acid racemisation measured in radiocarbon-dated specimens of fossil estuarine molluscs, collected from Lake Illawarra, a Holocene barrier estuary in New South Wales, Australia, is evaluated in the context of results of laboratory-induced racemisation established in heating (simulated ageing) experiments. The general kinetic trend of aspartic acid racemisation in both heating experiments and fossil molluscs Anadara trapezia and Notospisula trigonella conforms to a model of apparent parabolic kinetics. Using the apparent parabolic kinetic model, numeric ages based on the degree of aspartic acid racemisation in the fossil molluscs have been calculated. An aminostratigraphy of the Lake Illawarra …
Recognition Of Late Cretaceous Hasanbag Ophiolite-Arc Rocks In The Kurdistan Region Of The Iraqi Zagros Suture Zone: A Missing Link In The Paleogeography Of The Closing Neotethys Ocean, Sarmad Ali, S Buckman, K Aswad, B Jones, S Ismail, A Nutman
Recognition Of Late Cretaceous Hasanbag Ophiolite-Arc Rocks In The Kurdistan Region Of The Iraqi Zagros Suture Zone: A Missing Link In The Paleogeography Of The Closing Neotethys Ocean, Sarmad Ali, S Buckman, K Aswad, B Jones, S Ismail, A Nutman
B. G. Jones
The Hasanbag igneous complex is situated near Sidekan, 100 km northeast of Erbil city, Kurdistan Region, within the Iraqi Zagros suture zone. It forms part of an ophiolite-bearing terrane referred to as the "Upper Allochthon" or Gemo-Qandil Group. The Hasanbag igneous complex consists predominantly of calc-alkaline basaltic andesites to andesites cut by microgabbro and diorite dikes, which previously were interpreted as a part of the Eocene Walash volcanic group. However, 40Ar-39Ar dates on Hasanbag igneous complex kaersutite (magmatic hornblende) indicate an Albian-Cenomanian age (106-92 Ma). This reveals a previously unrecognized portion of the Late Cretaceous, Neotethyan ophiolite-arc complexes in the …
The Charophyte Lamprothamnium Succinctum As An Environmental Indicator: A Holocene Example From Tom Thumbs Lagoon, Eastern Australia, Adriana Garcia, Brian Jones, Bryan Chenhall, Colin Murray-Wallace
The Charophyte Lamprothamnium Succinctum As An Environmental Indicator: A Holocene Example From Tom Thumbs Lagoon, Eastern Australia, Adriana Garcia, Brian Jones, Bryan Chenhall, Colin Murray-Wallace
B. G. Jones
The palaeobiota from a middle to late Holocene succession in Tom Thumbs Lagoon, N.S.W., Australia, reflects a range of environmental conditions caused by sea-level changes and active estuarine sedimentation. At the base of the succession (~ -0.4 m AHD) a thin bed, containing molluscs dated at 6.7 ka B.P. by radiocarbon and amino acid racemisation, and foraminifers is indicative of open estuarine conditions. From +0.35 m AHD towards the top of the sequence the charophyte Lamprotharanium succinctum occurs in subrecent deposits. This species is charactedsed here by statistical measurements, and new characters are described and illustrated. The charophytes record a …
Anthropogenic Effects In A Coastal Lagoon: Geochemical Characterization Of Burrill Lake, Nsw, Australia, Brian Jones, Hannah Killian, Bryan Chenhall, Craig Sloss
Anthropogenic Effects In A Coastal Lagoon: Geochemical Characterization Of Burrill Lake, Nsw, Australia, Brian Jones, Hannah Killian, Bryan Chenhall, Craig Sloss
B. G. Jones
Burrill Lake, a small coastal lagoon on the south coast of New South Wales, developed as an impounded drowned river valley following the post-glacial marine transgression. Marine sand fills the entrance to the lagoon whereas the back-barrier basin has accumulated organic-rich mud and sandy bayhead deltas. The bilobate form of the estuary coincides with two different catchment lithologies and land use patterns. The northern lobe drains an agricultural catchment and has a much larger bayhead delta than the southern lobs that drains natural and state forest. Sedimentation rates within the muddy lagoonal deposits are about 1.7 mm/yr. The distributions of …
Fluvial Architecture Of The Hawkesbury Sandstone (Triassic), Near Sydney, Australia, Andrew Miall, Brian Jones
Fluvial Architecture Of The Hawkesbury Sandstone (Triassic), Near Sydney, Australia, Andrew Miall, Brian Jones
B. G. Jones
The Hawkesbury Sandstone has long been assumed to represent the deposits of a large braided river system, comparable in style and magnitude with the modern Brahmaputra River of Bangladesh. Such an interpretation is based mainly on the common occurrence of very large-scale crossbedding, but no architectural studies of the unit have hitherto been carried out. This paper represents a first attempt to estimate the magnitude of Hawkesbury channels and bars on the basis of the preserved architectural evidence. Photomosaics were constructed of two cliff sections south of Sydney, one 5.6 km in length. On the basis of these profiles we …