Geoscience Australia contributed a multi-satellite, multi-year weekly time series to the International DORIS Service combined submission for the construction of International Terrestrial Reference Frame 2008 (ITRF2008). This contributing solution was extended to a study of the capability of DORIS to dynamically estimate the variation in the geocentre location. Two solutions, comprising different constraint configurations of tracking network, were undertaken. The respective DORIS satellite orbit solutions (SPOT-2, SPOT-4, SPOT-5 and Envisat) were verified and validated by comparison with those produced at the Goddard Space Flight Center (GSFC), DORIS Analysis Centre, for computational consistency and standards. In addition, in the case of Envisat, the trajectories from the GA determined SLR and DORIS orbits were compared. The results for weekly dynamic geocentre estimates from the two constraint configurations were benchmarked against the geometric geocentre estimates from the IDS-2 combined solution. This established that DORIS is capable of determining the dynamic geocentre variation by estimating the degree one spherical harmonic coefficients of the Earth's gravity potential. It was established that constrained configurations produced similar results for the geocentre location and consequently similar annual amplitudes. For the minimally constrained configuration Greenbelt - Kitab, the mean of the uncertainties of the geocentre location were 2.3, 2.3 and 7.6 mm and RMS of the mean uncertainties were 1.9, 1.2 and 3.5 mm for the X, Y and Z components respectively. For GA_IDS-2_Datum constrained configuration, the mean of the uncertainties of the geocentre location were 1.7, 1.7 and 6.2 mm and RMS of the mean uncertainties were 0.9, 0.7 and 2.9 mm for the X, Y and Z components respectively. The mean of the differences of the two DORIS dynamic geocentre solutions with respect to the IDS-2 combination were 1.6, 4.0 and 5.1 mm with an RMS of the mean 21.2, 14.0 and 31.5 mm for the Greenbelt - Kitab configuration and 4.1, 3.9 and 4.3 mm with an RMS 8.1, 9.0 and 28.6 mm for the GA_IDS-2_Datum constraint configuration. The annual amplitudes for each component were estimated to be 5.3, 10.8 and 11.0 mm for the Greenbelt - Kitab configuration and 5.3, 9.3 and 9.4 mm for the GA_IDS-2_Datum constraint configuration. The two DORIS determined dynamic geocentre solutions were compared to the SLR determined dynamic solution (which was determined from the same process of the GA contribution to the ITRF2008 ILRS combination) gave mean differences of 3.3, -4.7 and 2.5 mm with an RMS of 20.7, 17.5 and 28.0 mm for the X, Y and Z components respectively for the Greenbelt - Kitab configuration and 1.1, -5.4 and 4.4 mm with an RMS of 9.7, 13.3 and 24.9 mm for the GA_IDS-2_Datum configuration. The larger variability is reflected in the respective amplitudes. As a comparison, the annual amplitudes of the SLR determined dynamic geocentre are 0.9, 1.0 and 6.8 mm in the X, Y and Z components. The results from this study indicate that there is potential to achieve precise dynamically determined geocentre from DORIS.

Controls on the evolution of Tapora Island, an active barrier island located opposite the entrance to the Kaipara Harbour on the high-energy west coast of the North Island of New Zealand are identified. Subsurface facies form an aggradational barrier island succession from subtidal to subaerial elevations. These data, combined with surface samples and geomorphic and geologic relationships, indicate that Tapora Island is the most recent barrier island at this location in the estuary, and forms part of a prograded coast opposite the entrance. Wave data indicate that ocean swell waves penetrate the inlet for approximately two hours either side of high tide and are capable of transporting sand onto the island. The combined effects of swell waves, abundant sediment supply, and exposed aspect are the critical factors that have formed the barrier island. Despite the 'sheltered' estuarine setting, Tapora Island has formed under conditions that are more akin to open ocean coasts. The origin and development of Tapora Island broadly conforms to the accumulating barrier island model.

Content: 1.Chaproniere GCH, Pigram CJ. Miocene to Pleistocene foraminiferal biostratigraphy of dredge samples from the Marion Plateau, offshore Queensland, Australia. 2.Scott DL. Architecture of the Queensland Trough: implications for the structure and tectonics of the northeastern Australia margin. 3.Wilkie J, Gibson G, Wesson V. Application and extension of the ML earthquake magnitude scale in the Victoria region. 4.Macphail MK, Kellett JR, Rexilius JP, O'Rorke ME. The "Geera Clay equivalent": a regressive marine unit in the Renmark Group that sheds new light on the age of the Mologa weathering surface in the Murray Basin. 5.Nicoll RS, Laurie JR, Roche MT. Revised stratigraphy of the Ordovician (Late Tremadoc-Arenig) Prices Creek Group and Devonian Poulton Formation, Lennard Shelf, Canning Basin, Western Australia. 6.Cruikshank BI, Hoatson DM, Pyke JG. A stream-sediment geochemical orientation survey of the Davenport Province, Northern Territory. 7.

Organic material incorporated in an ore or a sediment may represent the resistant parts of organisms, organic compounds adsorbed on inorganic minerals, organic precipitates from chemical reactions in basin waters, or detrital grains eroded from older carbonaceous rocks. In addition, hydrocarbons may be generated elsewhere in a basin before migrating into and being retained in the rocks under consideration. During diagenesis and metamorphism under non-oxidising conditions, the chemical composition of organic matter from all sources progressively changes as volatile compounds (including carbon dioxide, water, and hydrocarbons) are evolved. All types of carbonaceous source material give graphite as the final solid product, but in various amounts, depending on their initial composition and subsequent history. Bacterial or aerial oxidation of solid organic materials is most rapid at low ranks and initially causes an increase in oxygen/carbon ratios before complete removal of carbonaceous matter is achieved. At high temperatures, oxidation by water can completely convert graphite to carbon dioxide. Data are given on the insoluble organic matter isolated by demineralisation of samples from the Red Sea, Julia Creek, McArthur River, Mount Isa, Broken Hill, Cobar, Woodlawn, Kambalda, Rum Jungle, Alligator River (Australia) and the Witwatersrand (South Africa). Most of these samples contain material, probably of algal origin, that is now at the graphitic stage of metamorphism. Organic matter from recent sediments in the Red Sea and ore-related rocks from McArthur River, Mount Isa, and Broken Hill show a progressive change in rank consistent with a syngenetic theory of ore formation. The presence (or even the absence) of carbonaceous material in an ore or sediment is a valuable parameter in reconstructing the chemical and biological environment of genesis and subsequent geological changes.

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High-grade metamorphic and felsic igneous rocks from the northern Prince Charles Mountains, East Antarctica, have been characterised geochemically and dated from SHRIMP zircon geochronological data. Around 980 Ma ago, voluminous magmas representing a combination of mantle-derived and intracrustal melts, including orthopyroxene-quartz monzonite (charnockite) on Loewe Massif and granitic and syenitic intrusions on Mount Collins, were emplaced during a regional high-grade tectonothermal event. Garnet leucogneiss sheets on Mount McCarthy, the products of local partial melting, were also emplaced at about this time. The geology of Fisher Massif is exceptional in that a ca 1280-Ma metavolcanic sequence and coeval granodiorite have been metamorphosed only up to the lower amphibolite facies, and intruded by a ca 1020-Ma biotite granite. None of the analysed sarnples shows in its isotopic systematics the effects of 500-Ma events, prominent elsewhere in East Antarctica. Rare inherited components 1850-1900 Ma old were found in some samples. A paragneiss on Mount Meredith yielded 2500- 2800-Ma and 1800-2100-Ma detrital zircon populations.

Examination of a simple, but quantitative parameter, Sf/So, the ratio of average salinity of a coastal waterway/marine source water salinity, both geographically and temporally, identified five major types of coastal environment around Australia: (i) runoff-dominated annually - found mostly on the eastern seaboard, where rainfall is near continuous year-round ; (ii) seawater-dominated annually- large embayments with small runoffs; (iii) evaporation-dominated annually - found on the fringes of arid climate zones of western Australia, such as Shark Bay and in South Australia, Spencer and St. Vincents Gulf; (iv) runoff-dominated in the summer monsoon and evaporation-dominated in the winter - e.g. the northern Australian estuaries near moist-tropical and semi-arid zones with summer rains; and (v) runoff-dominated in the winter and evaporation-dominated in the summer-e.g. the estuaries and coastal lakes of southwestern Australia. A general equation of salt and water mass balances, including an evaporation term, was used to estimate freshwater residence time, a proxy for dissolved anthropogenic input. Geographic and temporal variation in climate forcing factors, notably seasonal variation in rain-fall and runoff and the net of evaporation and precipitation, exert major controls on residence time and flushing of Australian coastal environments. The inverse of the residence time (1/T day-1) is an important parameter in the estimation of quantities of dissolved anthropogenic inputs flushed from the coastal environment to the sea. As such, it is one important parameter for evaluating coastal water quality.

Limited Australian data on sedimentary processes- C, N, P, Fe and Si diagenesis at the sediment/water interface- have been reviewed. These and the results of more recent work with benthic chambers indicate that the fractionation and transfer of N, P and Si from sedimentary particulates to pore waters control the speciation and concentrations of N, P and Si at the sediment- water interface and, ultimately, nutrients available for phototrophic growth. Oxygen and sulphate are quantitatively the most important oxidants recycling organic carbon. Secondary oxidants, such as nitrate (sourced from sedimentary nitrification or the overlying waters), are important for denitrification and the N balance. Iron is an intermediary in the nitrification and denitrification processes and also controls (in part) P fluxes across the sediment- water interface. The Port Phillip Bay environmental study demonstrated the contribution benthic chambers have made, so far, to studies of sediment- water exchange in Australian environments. These include the following: 1) defining the stoichiometry between the oxidation of organic carbon via oxygen, nitrate and sulphate reductions and the remineralisation of N, P and Si from sediments to overlying waters; 2) calculating net benthic respiration and nutrient (N, P and Si) fluxes (and speciation of N) to the water column; 3) identifying transport processes either advection (e.g. bioirrigation) or diffusion controlling metabolite transfers between the sediments and overlying waters; 4) investigating interactions between benthic flora and sediments; and 5) evaluating the controls and effects of benthic processes on water quality. The interpretations are more robust when combined with specific biomarker analyses of the most abundant organic matter source in the sediments, including its nature- fresh versus old and refractory. A limited survey of TOC content in Australian sediments found it to vary between < 1 % wt in unimpacted estuarine and shelf sediments to near 10% wt in a coastal lake in Western Australia impacted by activities in the catchment. Highest TOC was, however, found in mangrove sediments (2-15% wt ) in tropical Queensland. TOC:TN and TOC :TP ratios in sediments are not unique indicators of organic matter sources. The ratios probably reflect (i) mixed planktonic (predominantly diatomaceous) and other plant inputs of various aged and reworked organic matter; (ii) early diagenesis-specifically, denitrification, which results in the significant loss of N to the atmosphere as N, gas; and (iii) solute/particle interactions, specifically P and Fe cycling. P is trapped in oxic to suboxic sediments, but is liberated to the overlying waters when interfacial sediments become anoxic.

Gosses Bluff, a prominent complex annular structure in central Australia, was produced by hypervelocity impact during the Late Jurassic. The impact occurred in the thick sedimentary succession close to the centre of a major sub-basin within the Amadeus Basin. The structure is well exposed and has good subsurface control as a consequence of earlier unsuccessful hydrocarbon exploration programs. It provides an opportunity to study the effects of impact on a sedimentary succession without basement involvement, and to evaluate the potential of such structures as hydrocarbon plays. Seismic data across the structure show that the original crater was 24 km in diameter, suggesting that originally a major ejecta blanket extended for at least 60 km beyond the rim. The underlying Neoproterozoic and Palaeozoic sedimentary rocks of the Amadeus Basin have been deformed to depths of several kilometres. Uplift at the centre of the Gosses Bluff structure is especially pronounced owing to rebound of the primary shock wave from the upper surface of the evaporites of the Bitter Springs Formation. The thermal effects of impact on outcrop and core samples have been studied from apatite fission-track analysis (AFTA). Samples from the crater floor and remnant crater fill indicate that no significant fission-track annealing has occurred in response to the impact. All samples preserve tracks that were formed before the impact (~140 Ma) and are consistent with the regional thermal history. AFTA data from central uplift samples indicate that the main thermal effect of impact was not heating, but cooling related to exhumation. Results have shown that, whereas shock-related fracturing enhanced porosity and permeability of underlying reservoir units to some extent, quartz cementation associated with impact reduced overall reservoir quality. The only potential hydrocarbon play, as yet untested, is the rim anticline formed beneath the crater rim as a response to post-impact salt migration. Ultimately, the major factor that limits the petroleum potential of the Gosses Bluff structure is the timing of events. The impact occurred too late in basin evolution for an effective seal to be deposited over the structure. Further, the structure formed at about 140 Ma, whereas petroleum was probably generated before 200 Ma. Thus, any hydrocarbons trapped in the structure probably represent migration from pre-impact accumulations. In spite of the limited petroleum potential at Gosses Bluff, it does provide an important analogue for buried impact structures with more favourable thermal histories.

Rivers flowing north and west across southeastern Australia are older than the formation of the eastern continental margin and the Murray Basin. In the Jurassic and most of the Cretaceous, Australia was bound by land to the east (Pacifica), from which rivers carried sediment to the Eromanga-Surat Basin. The Otway-Gippsland Basin, bound to the north by the Victoria Divide, accumulated sediment from the early Cretaceous. At about 80 Ma, tectonic rifting along the line of the present continental shelf cut off the headwaters of Australian rivers then rising in Pacifica, beheading many rivers and reducing the sediment supply to the sedimentary basins. The input of coarse fluvial sediment to the Eromanga-Surat Basin ceased, but was maintained to the Otway-Gippsland Basin. In the Palaeocene, the Murray Basin started to sink, creating a divide between the Murray and Eromanga-Surat Basins and cutting off the southern sediment supply to the latter. Down-warping along the Tasman Sea margin formed the Great Divide between Tasman Sea drainage and the inland sedimentary basins. Rivers east of this divide were reversed, and a Great Escarpment was formed which retreated inland. Cainozoic volcanicity and Miocene faults with throws of hundreds of metres have further complicated the topography. The history derived from the study of river development and the evolution of major divides is paralleled by that of basin sedimentation. Basin down-warping formed the major divides, and led to the erosional development of the present landscape .