Browsing by Author "Moss, PT"
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- ItemAMS C14 dating using pollen concentrate for sediments with low organic content in the tropics of Australia(Elsevier, 2007-07) Moss, PT; McTainsh, GH; Dunbar, GB; Dickens, G; Jacobsen, GEThis study discusses the results of using pollen concentrate for AMS C14 dating of sediments with low organic content for two sites in the tropical north of Australia. The first site from the Mitchell Plateau in the Kimberly region of Western Australia is a swamp deposit within a small enclosed drainage basin, with a high content of inorganic sediments. Seven AMS C-14 dates have been obtained for the first 70 cm of this record, which provides a relatively consistent age chronology that stretches back 1670 BP and can be directly compared with pollen data from the same depths. The second site, ODP 820, from the humid tropics region of northeastern Queensland consists of marine sediments with high values of Calcium Carbonate. Several AMS C-14 on foraminifera have been obtained for this record, which provide a consistent age chronology for the first 8 m of the core and which is thought to cover the last 44,000 BP. More recently, seven AMS C-14 dates based on pollen concentrate have been obtained and have been directly compared with the forminiferal derived ages, as well as the core’s pollen record. The dates and concurrent pollen data provide a better understanding of the sedimentological processes, both marine and terrestrial, that have been operating in the region, as well as providing insight into the nature of the reworking of pollen grains in marine sediments.
- ItemChanges in hydrology and carbon cycling following Late Holocene deforestation in a New Zealand lake catchment(European Geosciences Union (EGU), 2018-04-13) Woodward, CA; Hua, Q; Tyler, JJ; Meredith, KT; Moss, PT; Gadd, PS; Zawadzki, ANew Zealand was one of the last major land masses to be impacted by humans, with two waves of settlement occurring in the last 800 years. Polynesian (Maori) settlers arrived in New Zealand ca. 1250 A.D., while major European settlement occurred after 1840 A.D. A major impact of both phases of settlement was clearance of indigenous forest. An increasing number of pollen and macroscopic charcoal records reveal the timing and extent of past forest clearance in New Zealand. Only a few records explore the wider implications of this land use change in terms of catchment biogeochemical cycles and aquatic ecosystem functioning. We used multiple proxies from a lake sediment core from a cleared catchment to explore changes in catchment hydrology and carbon cycling after forest clearance. One of the most interesting findings emerged from paired radiocarbon dates on terrestrial targets (e.g. leaves and charcoal) and seeds from the aquatic plant Myriophyllum. The offset between terrestrial and aquatic radiocarbon ages increased to 1000 years and then decreased to 100 years within three centuries of local Maori forest clearance. There was a further increase in the radiocarbon age offset to 1500 radiocarbon years within decades of the start of the European forest clearance. We argue that the offset between terrestrial and aquatic radiocarbon ages results from an increased contribution of old dissolved inorganic carbon from groundwater to the lake after forest clearance. Forest clearance reduced evapotranspiration, increased aquifer recharge and increased the contribution of groundwater to the lake. This interpretation is supported by a major increase in the δ 13C of Myriophyllum seeds following Maori deforestation. At the time of abstract submission the results are pending for δ 18O analysis on Myriophyllum seeds and aquatic insects. This will provide a further test for changes in catchment hydrology following deforestation. Reviews of catchment impacts on hydrology and carbon cycling have shown an increased catchment water yield and flux of old carbon in disturbed catchments. Our study provides one of the most comprehensive records of forest clearance and provides valuable insights into the causal mechanisms and consequences of these changes. © Author(s) 2018. CC Attribution 4.0 license.
- ItemCoherent patterns of environmental change at multiple organic spring sites in northwest Australia: evidence of Indonesian-Australian summer monsoon variability over the last 14,500 years(Elsevier, 2018-09-15) Field, E; Tyler, JJ; Gadd, PS; Moss, PT; McGowan, HA; Marx, SKAt present, knowledge of late Quaternary variability of the Indonesian-Australian summer monsoon in the Australian tropics is limited. Organic spring deposits, which occur throughout the Kimberley region of northwest Australia, are valuable archives that contain records spanning the past ∼14,500 years. In this study we compare multiple proxies from three organic springs. Principal Components Analyses demonstrates similar patterns of change in the elemental and non-pollen palynomorph (NPP) datasets between the springs, implying regional drivers are responsible for changes in these proxies. By comparison, the pollen records differ between each of the springs, with the assemblage at each thought to be influenced by spring recharge and evolution rather than climate variability. In order to empirically and objectively assess the synchronicity of changes, we applied Monte Carlo empirical orthogonal function (MCEOF) analysis to one variable in each μXRF and NPP dataset (Si/Ti ratios and Pseudoschizaea accumulation rates, as these proxies are expected to reflect hydrological conditions in springs) to assess regional patterns of change in site moisture. This analysis revealed periods of increased monsoonal precipitation from ∼14,500–7500 cal. yr BP corresponding with deglacial sea level rise, high orbital tilt coupled with warmer sea surface temperatures, and with possible links to a southward migration of the Inter Tropical Convergence Zone (ITCZ) during the Younger Dryas. Monsoonal precipitation was reduced from 7500 cal. yr BP coinciding with the culmination of deglacial sea level rise and a possible northward shift in the mean position of the ITCZ, in addition to between 2600 and 1000 cal. yr BP corresponding with increased moderate-to-strong ENSO events. ©2018 Elsevier Ltd
- ItemComparative ages of pollen and foraminifera in the ODP 820 marine core(Australian Institute of Nuclear Science and Engineering (AINSE), 2007-11) Moss, PT; Dunbar, GB; Dickens, G; Jacobsen, GEThis study discusses the results of using pollen concentrate for AMS C14 dating of sediments from the Ocean Drilling Program (ODP) 820 marine core and these dates are compared with existing AMS C14 dates derived from foraminifera for the same record. This will address the question of reworking, and consequent time lag between production and deposition of pollen in the Queensland Trough, as well as providing an additional age model from the terrestrial record (i.e. pollen) that can be directly compared with the existing age model derived from marine sediments (i.e. foraminifera). In addition, these results will contribute to our ability to interpret marine palynological records and provide additional insight into the sedimentological processes operating on the northeastern Queensland continental margin.
- ItemEcosystem and landscape change in the ‘Top End’ of Australia during the past 35 kyr(Elsevier, 2021-12-01) Samuel, KM; Reynolds, W; May, JH; Forbes, MS; Stromsoe, N; Fletcher, MS; Cohen, T; Moss, PT; Mazumder, D; Gadd, PSThe Indo-Australian Summer Monsoon (IASM) is the dominant climate feature of northern Australia, affecting rainfall/runoff patterns over a large portion of the continent and exerting a major control on the ecosystems of the Australia's Top End, including the viability of wetland ecosystems and the structure of the woody savanna, which characterises Northern Australia. We examined the behaviour the IASM from 35 ka using proxy data preserved in the sediments of Table Top Swamp, a small seasonal swamp in northern Australia. Elemental data, stable C and N isotopes, pollen and sedimentary data were combined to develop a picture of monsoon activity and ecosystem response. Results demonstrated that between 35 and 25 ka conditions were drier and more stable than present, with a more grass dominated savanna and limited wetland development, implying reduced IASM activity. After ~25 ka, there is evidence of increased moisture at the study site, but also increased IASM variability. However, despite evidence of at least periodic increases in moisture, including periods of wetland establishment, the IASM displayed a subdued response to peak precession insolation forcing by comparison to the other global monsoon systems. Instead, the greatest change occurred from ~10 ka when the continental shelf flooded, increasing moisture advection to the study site and resulting in establishment of a quasi-permeant wetland. Whereas the early Holocene was marked by both the onset of pollen preservation and a wetter vegetation mosaic, indicative of a consistently active IASM, the mid-late Holocene was marked by drier vegetation, increased fire, but also increased C3 vegetation and runoff, implying increased IASM variability. Holocene changes in ecosystem dynamics occur coincident with an expansion in human population, which likely also influenced vegetation and landscape response at the study site. © 2021 Elsevier B.V.
- ItemEnvironmental context for late holocene human occupation of the South Wellesley Archipelago, Gulf of Carpentaria, northern Australia(Elsevier, 2015-10-22) Moss, PT; Mackenzie, LL; Ulm, S; Sloss, CR; Rosendahl, D; Petherick, LM; Steinberger, L; Wallis, LA; Heijnis, H; Petchey, F; Jacobsen, GEA 2400 year record of environmental change is reported from a wetland on Bentinck Island in the southern Gulf of Carpentaria, northern Australia. Three phases of wetland development are identified, with a protected coastal setting from ca. 2400 to 500 years ago, transitioning into an estuarine mangrove forest from ca. 500 years ago to the 1940s, and finally to a freshwater swamp over the past +60 years. This sequence reflects the influence of falling sea-levels, development of a coastal dune barrier system, prograding shorelines, and an extreme storm (cyclone) event. In addition, there is clear evidence of the impacts that human abandonment and resettlement have on the island's fire regimes and vegetation. A dramatic increase in burning and vegetation thickening was observed after the cessation of traditional Indigenous Kaiadilt fire management practices in the 1940s, and was then reversed when people returned to the island in the 1980s. In terms of the longer context for human occupation of the South Wellesley Archipelago, it is apparent that the mangrove phase provided a stable and productive environment that was conducive for human settlement of this region over the past 1000 years. © 2015 Published by Elsevier Ltd.
- ItemExtended residence times for foraminifera in a marine-influenced terrestrial archaeological deposit and implications for palaeoenvironmental reconstruction(Elsevier, 2016-02-01) Nagel, T; Rosendahl, D; Hua, Q; Moss, PT; Sloss, CR; Petchey, F; Ulm, SAccelerator Mass Spectrometry (AMS) radiocarbon dating and taphonomic grading was undertaken on foraminifera preserved in the archaeological shell matrix site of Thundiy, Bentinck Island, southern Gulf of Carpentaria, Australia. Foraminifera were assigned to one of six taphonomic grades ranging from pristine to severely abraded. AMS dating demonstrates a weak relationship between preservation status and age. Foraminifera ages are inconsistent with multiple ages on marine shell from the same deposit implying significant sediment transport system residence ages (the time between death of the organism and final deposition) for foraminifera in the deposit. Results demonstrate that foraminifera cannot be assumed to be contemporary with other components of the sedimentary context in which they occur, indicating that caution is required in interpreting chronologies and palaeoenvironmental records based on foraminifera recovered from highly dynamic depositional settings. Findings point to the potential of foraminifera AMS dating of coastal archaeological deposits to contribute to evaluations of site integrity and chrono-stratigraphic analyses. © 2015, Elsevier Ltd.
- ItemGeochemical investigation of the South Wellesley Island wetlands: insight into wetland development during the Holocene in tropical northern Australia(Sage, 2016-09-28) Mackenzie, LL; Heijnis, H; Gadd, PS; Moss, PT; Shulmeister, JThe South Wellesley Islands in the Gulf of Carpentaria, northern Australia, were the recent focus of a palynological investigation which found vegetation change during the Holocene was driven by coastal progradation and regional climate. Here, we present new elemental data from x-ray fluorescence core scanning which provides non-destructive, continuous and high resolution analysis from three wetlands across Bentinck Island, the largest of the South Wellesley Islands. Elemental data and grain size analyses are combined with lead-210 (210Pb) and accelerator mass spectrometry (AMS) carbon-14 (14C) dates. An open coastal environment was present 1250 cal. a BP on the south east coast of Bentinck Island, with sediment supply incorporating fluvial deposition and detrital input of titanium and iron from eroding lateritic bedrock. Prograding shorelines, dune development and river diversion formed a series of swales parallel to the coast by ~800 cal. a BP, forming the Marralda wetlands. Wetlands developed at sites on the north and west coasts ~500 and ~450 cal. a BP, respectively. Geochemical and grain size analyses indicate that wetlands formed as accreting tidal mudflats or within inter-dune swales that intercepted groundwater draining to the coastal margins. The timing of wetland initiation indicates localised late-Holocene sea level regression, stabilisation and coastal plain development in the Gulf of Carpentaria. Elemental data provide new records of wetland development across Bentinck Island, highlighting the value of a multi-proxy approach to understanding environmental change during the Holocene in tropical northern Australia. © 2020 by SAGE Publications
- ItemHolocene sea-level change and coastal landscape evolution in the southern Gulf of Carpentaria, Australia(International Union for Quaternary Research (INQUA), 2019-07-30) Sloss, CR; Northdurft, L; Hua, Q; O'Connor, SG; Moss, PT; Rosendahl, D; Petherick, LM; Nanson, RA; Mackenzie, LL; Sternes, A; Jacobsen, GE; Ulm, SA Holocene sea-level history for the southern Gulf of Carpentaria has been constructed based on a review of previously published data, combined with data collected for this study from a variety of sea-level proxies. These sea-level proxies include beach ridges, claypans, mangrove swamps, fossilized in situcoral reefs, beachrock and aeolinite deposits. Results confirm that rising sea-levels during the last Post-Glacial Marine transgression beached the Arafura Sill ca. 11,700 years ago (-53 m), resulting in a change from lacustrine to a marine environment. Sea levels continued to rise to ca. -30 m by 10,000 years ago. By 7,700 cal. yr BP sea-level reached PMSL and continued to rise an elevation of between 1.5 and 2 m above present mean sea-level by 7,000 years ago. Elevated sea levels resulted in the development of raised coral reefs, beach-rock and aeolinite deposits, and the initiation of chenier plains and beach ridges. Sea-level remained ca. +1.5 m above PMSL during the Holocene highstand, accompanied by distinct phases of beach-ridge and chenier plain development. The highstand was followed by arapid regression to within ±0.5 m of PMSL by ca. 3,500 cal. yr BP. When placed into a wider regional context results from this study show thatcoastal landscape evolution in the tropical north of Australia was not only dependenton sea-level change but also show a direct correlation with Holocene climatevariability. Specifically, the formation and preservation of beach-rock deposits,intertidal successions, beach and chenier ridge systems hold valuable sea-level and Holoceneclimate proxies that can contribute to the growing research into lowerlatitude Holocene sea-level and climate histories. ©2019 The Authors.
- ItemHolocene sea-level change and coastal landscape evolution in the southern Gulf of Carpentaria, Australia(SAGE, 2018-09-01) Sloss, CR; Nothdurft, L; Hua, Q; O'Connor, SG; Moss, PT; Rosendahl, D; Petherick, LM; Nanson, RA; Mackenzie, LL; Sternes, A; Jacobsen, GE; Ulm, SA revised Holocene sea-level history for the southern Gulf of Carpentaria is presented based on new data from the South Wellesley Archipelago and age recalibration of previous research. Results confirm that rising sea levels during the most recent post-glacial marine transgression breached the Arafura Sill ca. 11,700 cal. yr BP. Sea levels continued to rise to ca. –30 m by 10,000 cal. yr BP, leading to full marine conditions. By 7700 cal. yr BP, sea-level reached present mean sea-level (PMSL) and continued to rise to an elevation of between 1.5 m and 2 m above PMSL. Sea level remained ca. + 1.5 between 7000 and 4000 cal. yr BP, followed by rapid regression to within ± 0.5 m of PMSL by ca. 3500 cal. yr BP. When placed into a wider regional context results from this study show that coastal landscape evolution in the tropical north of Australia was not only dependent on sea-level change but also show a direct correlation with Holocene climate variability. Specifically, the formation and preservation of beach-rock deposits, intertidal successions, beach and chenier ridge systems hold valuable sea-level and Holocene climate proxies that can contribute to the growing research into lower latitude Holocene sea-level and climate histories. © The Author(s) 2018
- ItemInsights for restoration: reconstructing the long-term responses, resilience and recovery time of vegetation, hydrology and peat condition to fire events in the Sebangau peatland, Central Kalimantan.(Australasian Quaternary Association Inc., 2022-12-06) Mohamed, R; Khairun, N; Moss, PT; Jacobsen, GE; Gallego-Sala, A; Charman, DJ; Yulianti, NThe palaeoecological and geochemical analysis of peat in the Natural Laboratory Peat-swamp Forest (NLPSF) has been used to identify the drivers of fire severity (FS) events and the associated responses, resilience and recovery time of this peatland system to aid in future restoration efforts in the Sebangau Peatland National Park (SPNP). From 4500 years BP to present, fire events have increased in severity and the drivers of FS included changes to sea level, increased frequency of El Niño events, increased biomass, and anthropogenic-driven degradation. The increased FS along with changes to the hydrology and peat condition over time have resulted in a vegetation turnover from mixed of peat forest and other vegetation types during the mid to late Holocene (4500 to 1201 years BP), to peat swamp forest (PSF) during the following ~800 years (1200 to 378 BP), lowland vegetation mixed with swamp forest (LMS) and open vegetation (OV) for the period between 377 and 134 years BP and finally, freshwater swamp forest (FSF) and OV in the last ~200 years (133 to -54 years BP) (Fig 1). From the Principal Component Analysis (PCA) and Generalised Linear Model (GLM), the changes to dominant vegetation types were due to changes in local hydrological conditions, as well as the fertilising effect from the combustion of organic matter (i.e. release of N and other minerals) and loss of soluble peat component during fire events. This information, together with the thresholds and lags of the responses, provided the following restoration insights: 1) Vegetation species have different fire intensity tolerances and transition from PSF to LMS and OV required a higher threshold with recovery time of approximately 70 to 80 years; 2) PSF expanded with higher peat nutrients (i.e. TN) and required wet peat environments compared to FSF and LMS but some PSF species (i.e. Eurya and Ilex) were able to cope with slightly drier peat conditions ; 4) Future revegetation in SPNP can focus on species such as Araceae, Restionaceae Myriophyllum, and Ficus as they were able to withstand high FS, less acidic and minimally wet conditions, while sustaining carbon accumulation in degraded tropical peatlands.
- ItemIntegration of ice-core, marine and terrestrial records for the Australian Last Glacial Maximum and Termination: a contribution from the OZ INTIMATE group(Wiley, 2006-10) Turney, CSM; Haberle, SG; Fink, D; Kershaw, AP; Barbetti, M; Barrows, TT; Black, M; Cohen, TJ; Corrège, T; Hesse, PP; Hua, Q; Johnston, R; Morgan, VI; Moss, PT; Nanson, GC; van Ommen, TD; Rule, S; Williams, NJ; Zhao, JX; D'Costa, D; Feng, YX; Gagan, MK; Mooney, SD; Xia, QThe degree to which Southern Hemisphere climatic changes during the end of the last glacial period and early Holocene (30-8 ka) were influenced or initiated by events occurring in the high latitudes of the Northern Hemisphere is a complex issue. There is conflicting evidence for the degree of hemispheric ‘teleconnection’ and an unresolved debate as to the principle forcing mechanism(s). The available hypotheses are difficult to test robustly, however, because the few detailed palaeoclimatic records in the Southern Hemisphere are widely dispersed and lack duplication. Here we present climatic and environmental reconstructions from across Australia, a key region of the Southern Hemisphere because of the range of environments it covers and the potentially important role regional atmospheric and oceanic controls play in global climate change. We identify a general scheme of events for the end of the last glacial period and early Holocene but a detailed reconstruction proved problematic. Significant progress in climate quantification and geochronological control is now urgently required to robustly investigate change through this period. © 2006 John Wiley & Sons, Ltd.