Academic literature on the topic 'Geology – New South Wales – Sydney Basin'

Surface reflection profiling with the Mini‐SOSIE technique successfully mapped shallow coal seam structure in the western Sydney Basin, New South Wales. Several minor faults and zones of fracturing were detected. In regions of thick Triassic sandstone cover, data quality was poor and unsuitable for geologic interpretation. Synthetic seismograms based on nearby borehole and petrophysical control show excellent agreement with the Mini‐SOSIE sections and illustrate the deleterious filtering effects of coal seams and sequences. To establish a phenomenological basis for seismic wave propagation in shallow coal measures, two vertical seismic profiles (VSPs) which used small explosive charges were recorded with high spatial and temporal sampling. Numerous multiple reflections were observed in the downgoing wave display. The isolated upgoing waves were migrated to yield blurred images of the main coal seams. The subsurface velocity function, also deduced from the VSP, shows broad correlation with the geologic log. The VSP seismograms are not simple because of the combined effects of wave absorption, scattering, and interference. Such problems impede recovery of fine structural detail from seismic data in the shallow environment, particularly when a surface energy source is used.

As in many growing urban areas, the prevention of environmental damage as Sydney spreads westward into the Hawkesbury-Nepean River basin is a major challenge for planners, managers and the local community, We surveyed macroinvertebrates at 45 river and stream sites in April-June 1996, and reviewed data from other sources, in order to assess the issues involved in conservation of the lotic macro invertebrate fauna, Regional richness is high with 443 recorded species and morphospecies, Cluster analysis showed community pattems related mainly to waterway size (separating the Hawkesbury-Nepean River from tributary streams), geology (tributaries on shale or sandstone), tidal intrusion and urbanization (impoverished faunas in urban streams). The ability of genus richness of mites and major insect orders to reflect overall genus richness at a site was limited, and Diptera and Trichoptera appear to have the greatest value as biodiversity predictors. Urban expansion is the major threat to lotic macro invertebrate communities in the region, but agriculture, flow regulation, sand and gravel ex1raction and introduced species have probably also impacted on the fauna, Streams with high conservation value for macroinvertebrates include those few on the Cumberland Plain and surrounding slopes that retain substantial indigenous vegetation in relatively undeveloped catchments. The Hawkesbury-Nepean River sfill harbours a rich faunal community and is also important for conservation, The development of effective strategies for conservation assessment and management is problematic for several reasons, Some species in the region are known to be vulnerable, but the status of most cannot be assessed because of a lack of taxonomic and zoogeographic information, Most "biodiversity indicator" concepts are of dubious value for aquatic macroinvertebrate conservation. A multi-faceted management approach emphasizing subcatchment reserves, riparian restoration and the control of threatening processes is required.

The coal seam gas content of the Late Permian Illawarra Coal Measures ranges from Methane that occurs within the basin was mainly derived as a by-product of coalification. Most of the CO2 was derived from intermittent magmatic activity between the Triassic and the Tertiary. This gas has subsequently migrated, mainly in solution, towards structural highs and accumulated in anticlines and near sealed faults.The total desorbable gas content of the coal seams is mainly related to depth, gas composition and geological structure. At depths

The Patonga Claystone, a red bed facies in the Narrabeen Group of the Sydney Basin, is one of the most unfavorable rock units in the basin from a geotechnical point of view. This rock unit is composed of sandstone, siltstone, mudstone and claystone. One of the unfavorable characteristics is the low shear strength, which causes instability of cut slopes; another is its slaking-prone behaviour. Numerous measurements of geotechnical properties, along with extensive mineralogical and geochemical determinations, were carried out to identify cause of this slaking behaviour. Key techniques were the use of quantitative X-ray diffractometry for mineralogical analysis, and the determination of slake durability index and related properties to evaluate the slaking behaviour under both standard and more extended conditions. Standard (two cycle) slake durability test results indicate a range from low to high slake durability index values, with some mudstone samples having very low durability and some sandstones having very high slake durability indices. Jar slake test results indicate that the rock samples break rapidly and/or develop several fractures (Ij = 4) in an as-received state, but degrade to a pile of flakes or mud (Ij = 1) if the samples are oven dried before testing. The results for jar slake testing of oven-dried material are comparable, for individual samples, to those obtained from the more comprehensive slake durability tests. The mineralogy of the samples was evaluated by quantitative X-ray diffraction techniques using the Rietveld-based Siroquant processing system. Comparison to independent chemical data show a generally good level of agreement, suggesting that the mineralogical analysis results are consistent with the chemical composition of the individual rock samples. Good correlations were also obtained between clay mineralogy determined from orientedaggregate XRD analysis of the <2 micron fraction and the results from powder diffractometry and Siroquant analysis of the whole-rock samples. Evaluation of the slake durability characteristics and other geotechnical properties in relation to the quantitative mineralogy suggests that quartz and feldspar form a rigid framework in the rocks that resists the disruptive pressures that cause slaking. Expansion of the clay minerals by various processes, including the incorporation of water into the interlayer spaces of illite/smectite as well as changes in pore pressures associated with entry of water into micro-fractures in the clay matrix, are thought to produce the disruptions that cause slaking and degradation. An abundant clay matrix also reduces the strength of the rock materials, probably because of the less rigid nature of the clay minerals relative to the quartz and feldspar particles. As well as the mineralogy, the loss on ignition (LOI) and water absorption percentage were found to provide good indicators of longer-term slaking behaviour. Both properties are also related to the overall clay content. Rock samples with water absorption values of <10, 10-15 and >15% behave as highly durable, intermediate and less durable materials respectively. Rocks with LOI values of greater than 5% by weight behave as less durable rock materials, at least for the strata encompassed by the present study. The water absorption and LOI values were also used to develop a predictive model of slake durability characteristics for the different rock materials in the Patonga Claystone, providing a relatively simple basis for predicting longer-term stability in a range of geotechnical studies.

"1990".
Thesis (PhD)--Macquarie University, School of Earth Sciences, 1991.
Bibliography: p. 596-630.
PART 1. INTRODUCTION AND METHODOLOGY -- General introduction -- Methodology -- Classification of ichnofacies and lithofacies as used in the present study -- Definition of trace fossil zones (intervals, subintervals and levels) -- General classification of the palaeoenvironments and summary overview of the stratigraphic and geographic distribution of palaeoenvironments in the study area -- PART 2. SYSTEMATIC ICHNOTAXONOMY -- Large dwelling-burrows -- U-shaped burrows -- Vertical cylindrical burrows -- Thalassinoides, Ophiomorpha, Spongeliomorpha and turn-arounds -- Pellets and ovoid-shaped structures -- Bedding-parallel feeding and/or dwelling structures -- Dendritic feeding-burrows -- Rosette-shaped structures -- Escape-structures -- Tracks, trails and resting-traces -- Body fossils and root-penetration structures -- Miscellaneous traces -- PART 3. SYNTHESIS AND CONCLUSIONS -- Trace fossil assemblages (suites) in intervals IC to IF and their distribution in the study area -- Interpretation of the palaeoenvironmental affinities of the trace fossil zones and depositional setting of the study area -- Palaeogeographic synthesis and conclusions.
The coastal exposures of the Triassic System in the Sydney Northshore area aggregate about 180 m in thickness and comprise the uppermost part of the Narrabeen Group (namely, in ascending stratigraphic order: the Bald Hill Claystone, the Garie Formation, and the Newport Formation, the latter divisible into Lower, Middle and Upper Members) and the overlying Hawkesbury Sandstone. With the exception of mainly allochthonous plant macrofossils and palynomorphs which occur sporadically and with varying abundance in the mudrock facies of these formations, environmentally-diagnostic body fossils are rare, and, where they occur, are nowhere unequivocally indicative of marine affinities. For this reasons, and because of the predominantly fluvial lithofacies characteristics exhibited by these formations throughout much of their stratigraphic extent and especially by their channel-form/channel-like sandstones lithosomes, most previous workers have interpreted these formations to be of fluvial or fluvio-lacustrine origin except possibly for several thin planar-and thinly-bedded fine-grained intervals encompassing the Garie and Newport Formations for which several lines of evidence, including lithofacies, equivocal palaeontological, and ichnological evidence, have prompted several workers to speculate a shallow- marine, possibility coastal lagoonal or estuarine origin. -- Although trace fossils occur in reasonable abundance at various stratigraphic levels within these uppermost Narrabeen Group rocks and particularly within the Newport Formation, they have hitherto received very little systematic study. A comprehensive study of this ichnofauna shows that it is relatively diverse, comprising almost 100 different ichnotaxa (including varietal categories) of predominantly invertebrate origin, and includes several new ichnogenera and ichnospecies among the more notable of which are: two large bioglyph-bearing dwelling-burrows of probable crustacean origin (Turimettichnus conaghani and T. webbyi) and one (Pytiniichnus trifurcatum) made either by a small reptile or an amphibian; a multi-stage spiral star-shaped feeding-trace (Helikospirichnus veeversi), probably made by a worm or worm-like deposit-feeder; several new species and varieties of Rhizocorallium (the first record of this ichnogenus in the Triassic of Australia); a new species and new variety of the saltatorial running vertebrate trackway Moodieichnus (an ichnogenus previously known only from the Late Permian of North America); and a new ichnogenus of vertical/steeply-inclined cylindrical branching dwelling-burrow (Barrenjoeichnus mitchelli). -- An alternating stratigraphic pattern of trace fossil abundance and diversity characterizes the upper Narrabeen Group strata in the Sydney Northshore area, and involves four relatively thin separate assemblage zones of relatively diverse ichnofauna and thicker intervening assemblage zones which lack ichnotaxo-nomic diversity. The assemblage zones of diverse trace fossils contain some elements in common to two or more zones, notably: Thalassinoides, Skolithos, Ophiomorpha, Chondrites, Rhizocorallium Palaeophycus, and Planolites, all of which are known to have unequivocal brackish- to shallow-marine palaeoecological affinities and which globally are characteristic of the Skolithos ichnofacies. Additionally, each of these four diverse assemblage zones is characterized by one or more particular index ichnogen-era which for convenience lend their name(s) to the zones as follows, in ascending stratigraphic order: Turimettichnus-Ophio-morpha assemblage zone; Skolithos-Diplocraterion assemblage zone; Helikospirichnus assemblage zone; and Rhizocorallium-Thalass inoides assemblage zone. The intervening ichnotaxonomically less-diverse and relatively impoverished assemblage zones are not similarly and separately named but are characterized by Barrenjoeichnus mitchelli and some species of Palaeophycus, Planolites and Skolithos as well as various plant-root petrification structures, all of which are here argued to have predominantly non-marine palaeoecological affinities. These latter assemblage zones can be referred to the Scoyenia-Teredolites ichnofacies. This stratigraphic pattern of alternating ichnologi-cally diverse and impoverished assemblage zones confirms the suggestions of previous workers (notably Bunny and Herbert, and Retallack) regarding the presence of brackish-/shallow-marine palaeoenvironmental influence in these Lower and Middle Triassic strata and allow for the first time the stratigraphic resolution of the marine strata into four marine tongues which are here named after their respective type localities. These are, in ascending order: The Turimetta Head Tongue (2 m to 3 m thick; extending from at least the middle part of the Bald Hill Clay-stone almost to the top of this formation); the St. Michaels Cave Tongue (4 m to 5 m thick; encompassing the Garie Formation and the lower part of the lower Member of the Newport Formation); the Bangalley Head Tongue (3 m to 5 m thick; extending from the uppermost part of the Lower Member into the lower part of the Middle Member of the Newport Formation); and the Palm Beach Tongue (3 m to 4 m thick; comprising the uppermost part of the Middle Member of the Newport Formation). The trace fossil assemblages in each of these marine tongues are indicative of a complex of brackish- to very shallow-marine low-energy palaeoenvi-ronments typical of modern coastal lagoons or estuaries and imply the presence of a protecting coeval topographic barrier of some kind to the east or southeast. This lagoon is herein called the Newport (Coastal) Lagoon and its development in the central-eastern part of the Sydney Basin coincides approximately with the geographic and depocentral axis of the basin which trends NW-SE and intersects the present coastline in the Sydney metropolitan area. The non-marine affinities of the impoverished and less-diverse trace fossil assemblages in the intervening and overlying strata are consistent with the fluvial/fluvio-lacustrine environmental interpretations of these thicker and predominantly sandstone-dominant intervals made by many other workers. Palaeocur-rent and petrographic data from these fluvial sediments show that the streams in which they formed debouched episodically into the Newport Lagoon variously from the northwest, west and southwest and were sourced variously from both the craton (Lachlan Fold Belt) to the southwest and the New England Orogen to the northeast.
With the exception of evidence of short-lived brackish-marine conditions at the base of the Narrabeen Group in the northeastern Sydney Basin and in the top of the Ashfield Shale in the Wianamatta Group (above the Hawkesbury Sandstone) in the central part of the basin, the Triassic System of the basin is dominated by fluvial/fluvio-lacustrine sediments and the presently described marine tongues of the Newport Lagoon in the uppermost Narrabeen Group are the only other presently known record of marine conditions during the Triassic history of the basin. The development of the Newport Lagoon in the geographic and depocentral axis of the basin attests to the presence of a mild short-lived marine transgression in the latest Early and early Middle Triassic at the end of a period of declining piedmont clastic alluviation from the coeval New England Orogen to the northeast and immediately prior to the onset of a new phase of fluvial sedimentation sourced from the craton to the southwest and manifested by the deposition of the Middle Triassic Hawkesbury Sandstone.
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xxxv, 630 p. ill., maps

The patterns of spatial distribution and abundance were investigated for moth assemblages in the eucalypt woodlands of the Sydney Basin. A total of 228 species of Lepidoptera, distributed among 25 families, were recorded from three national parks located on the perimeter of the Sydney metropolitan region.From within the eucalypt woodland habitat of the Sydney Basin, the study investigated the spatial variation of night-flying Lepidoptera present at several different scales of observation, from the trap level through to across the landscape. Assemblages varied with spatial scale, with uniformity occurring across the landscape as a whole, however becoming patchy at finer spatial scales. Multivariate and turnover analysis indicated that although heterogeneity of abundance and richness may vary significantly depending on spatial scale, sites and national parks contained their own unique suite of species in comparison to one another.The structure of the assemblages of moths in the eucalypt woodlands of the Sydney Basin can vary, and is dependant on the level of spatial scale of observation. Further study needs to be conducted at a range of temporal scales to ascertain the presence of patterns in the Lepidoptera communities in the Sydney region in order to contribute to the development of suitable conservation strategies in the Sydney Basin.

The three-dimensional thermal maturity pattern has been investigated and the hydrocarbon generation potential assessed for the Permian and Triassic sequences of the southern Bowen and northern Gunnedah Basins and the lower part of the overlying Jurassic Cretaceous Surat Basin sequence in northern New South Wales. An oil-source rock correlation also has been investigated in the Gunnedah Basin. Vitrinite reflectance measurements were conducted on 256 samples from 28 boreholes. A total of 50 of these samples were subjected to Rock-Eval pyrolysis analysis, and 28 samples extracted for additional organic geochemical studies (GCMS). A re-evaluation of the stratigraphy in the southern Bowen Basin and a stratigraphic correlation between that area and the northern Gunnedah Basin was also included in the study. An overpressured shaly interval has been identified as a marker bed within the lower parts of the Triassic Moolayember and Napperby Formations, in the Bowen and Gunnedah Basins respectively. Suppressed vitrinite reflectance in the Permian sequence was used as another marker for mapping the stratigraphic sequence in the southern Bowen Basin. The Permian sequence in the Bowen Basin thins to the south, and probably pinches out over the Moree High and also to the west. The coal-bearing Kianga Formation is present in the north and northeastern parts of the study area. A disconformity surface between Digby and Napperby Formations in the Gunnedah Basin is probably time-equivalent to deposition of the Clematis Group and Showgrounds Sandstone in the Bowen Basin. The Clematis Group is absent in the study area, and the Moolayember Formation considered equivalent to the Napperby Formation. Although in many cases core samples were not available, handpicking of coal or shaly materials from cuttings samples where geophysical log signatures identify these materials helped in reducing contamination from caved debris. Histogram plots of reflectance also helped where the target and caved debris were of similar lithology. Vertical profiles of the vitrinite reflectance identified suppressed intervals in the study area due to marine influence (Back Creek Group and Maules Creek Formation) and liptinite rich source organic matter (Goonbri Formation). The suppression occurs due to the perhydrous character of the preserved organic matter. High reflectance values were noted within intrusion-affected intervals, and two types of igneous intrusion profiles were identified; these are simple and complex profiles. An isoreflectance map for the non-suppressed interval at the base of the Triassic sequence in the southern Bowen Basin shows that the organic matter is mature more towards the east close to the Goondiwindi Fault, and also towards the west where the Triassic sequence directly overlies the basement. High values also occur over the Gil Gil Ridge in the middle, to the south over the Moree High, and to the north where the sequence is thicker. The reflectance gradient in the suppressed intervals is higher than in the overlying non-suppressed sequences, especially when the rank has resulted from burial depth. Tmax from Rock-Eval pyrolysis was found to be lower in the perhydrous intervals, and was high in mature and igneous intrusion-affected intervals. Based on the source potential parameters, the Permian Back Creek Group is a better source than the Kianga Formation, while the Goonbri Formation is better than the Maules Creek Formation. The Triassic Napperby Formation has a fair capacity to generate oil, and is considered a better source rock than the equivalent Moolayember Formation. The Jurassic Walloon Coal Measures is a better source than Evergreen Formation, and has the best source rock characteristics, but is immature. The Rock-Eval S1 value shows better correlation with extracted hydrocarbon compounds (saturated and aromatics) than the total extractable organic matter. This suggests that solvent extraction has a greater ability to extract NSO compounds than temperature distillation over the Rock-Eval S1 interval. Terrestrial organic matter is the main source input for the sequences studied. This has been identified from organic petrology and from the n-alkane distributions and the relatively high C29 steranes and low sterane/hopane ratios. The absence of marine biomarker signatures in the Permian marine influenced sequence, could be attributed to their dilution by overwhelming amounts of non-marine organic matter. A mainly oxic to suboxic depositional environment is inferred from trace amounts of 25-NH, BNH and TNH. This is further supported by relatively high pr/ph ratios. Although C29/C30 is generally regarded as an environmental indicator, high values were noted in intrusion-affected samples. The 22S and 20S ratios were inverted ????reaches pseudo-equilibrium???? in such rapidly heated, high maturity samples. The ratio of C24 tetracyclic terpane to C21-C26 tricyclic terpanes decreases, instead of increasing, within the Napperby Formation close to a major igneous intrusive body. The 22S ratio, which is faster in reaction than the other terpane and sterane maturity parameters, shows that the Permian sequence lies within the oil generation stage in the Bowen Basin, except for a Kianga Formation sample. The Triassic sequence is marginally mature, and the Jurassic sequence is considered immature. In the Gunnedah Basin, the Permian sequence in Bellata-1 and Bohena-1, and the Triassic sequence in Coonarah-1A, lie within the oil generation range. In the intrusion-affected high maturity samples, the ratio is reaches pseudo-equilibrium. This and other terpane and sterane maturity parameters are not lowered (suppressed) in the perhydrous intervals. The ???????? sterane ratio, however, is slowest in reaction to maturity, and variations in low maturity samples are mainly due to facies changes. Diasterane/sterane ratios, in the current study, increase with increasing TOC content up to 5% TOC, but decrease in rocks with higher TOC contents including coals. Highly mature samples, as expected, in both cases are anomalous with high ratios. Calculated vitrinite reflectance based on the method of Radke and Welte (1983), as well as MPI 1 and MPI 2, shows the best comparison to observed values. These aromatic maturity parameters are lowered within the reflectance-suppressed intervals. Oil stains in the Jurassic Pilliga Sandstone in the Bellata-1 well have been identified as being indigenous and not due to contamination. The vitrinite reflectance calculated to the oil stain suggests that the source rock should be within a late mature zone. Such high maturity levels are only recognised within intrusion-affected intervals. A close similarity between the oil stain sample and the intruded interval of the Napperby Formation is evident from the thermal maturity and biomarker content. Hydrocarbon generation and expulsion from the lower part of the Napperby Formation as a result of igneous intrusion effects is suggested as the source of the oil in this particular occurrence. Terpane and sterane maturity parameters increase with increasing burial depth in the intervals with suppressed (perhydrous) vitrinite reflectance. The generation maturity parameters also increase through intervals with perhydrous vitrinite, which suggests that hydrocarbons continue to be generated and the actual amount is increasing even though traditional rank ????????????stress???????????? maturity parameters are lowered. Accordingly, the Permian sequences in the lower part of the Bowen Basin are at least within the peak oil generation zone, and probably within late oil generation in the north and northeast of the study area. To generate significant amounts of hydrocarbon, however, the thickness of the shaly and coaly intervals in the Permian sequence is probably a critical parameter. In the Gunnedah Basin, a significant amount of hydrocarbon generation is probably only possible as a result of igneous intrusions.

Thesis (PhD)--Macquarie University, Division of Environmental & Life Sciences, Department of Earth and Planetary Sciences, 2005.
Bibliography: leaves 202-224.
Introduction -- Geological setting of the New England Fold Belt -- Regional geophysical investigation -- Data acquisition and reduction -- Modelling and interpretation of magnetic data over the Peel Fault -- Modelling and interpretation of magnetic data over the Mooki Fault -- Gravity modelling of the Tamworth Belt and Gunnedah Basin -- Interpretation and discussion -- Conclusions.
This thesis presents new magnetic and gravity data for the Southern New England Fold Belt (SNEFB) and the Gunnedah Basin that adjoins to the west along the Mooki Fault in New South Wales. The SNEFB consists of the Tamworth Belt and Tablelands Complex that are separated by the Peel Fault. The Tablelands Complex to the east of the Peel Fault represents an accretionary wedge, and the Tamworth Belt to the west corresponds to the forearc basin. A total of five east-north-east trending gravity profiles with around 450 readings were conducted across the Tamworth Belt and Gunnedah Basin. Seven ground magnetic traverses of a total length of 60 km were surveyed across the bounding faults of the Tamworth belt, of which five were across the Peel Fault and two were across the Mooki Fault. The gravity data shows two distinct large positive anomalies, one over the Tamworth Belt, known as the Namoi Gravity High and another within the Gunnedah Basin, known as the Meandarra Gravity Ridge. All gravity profiles show similarity to each other. The magnetic data displays one distinct anomaly associated with the Peel Fault and an anomaly immediately east of the Mooki Fault. These new potential field data are used to better constrain the orientation of the Peel and Mooki Faults as well as the subsurface geometry of the Tamworth Belt and Gunnedah Basin, integrating with the published seismic data, geologic observations and new physical properties data. --Magnetic anomalies produced by the serpentinite associated with the Peel Fault were used to determine the orientation of the Peel fault. Five ground magnetic traverses were modelled to get the subsurface geometry of the serpentinite body. Modelling results of the magnetic anomalies across the Peel Fault indicate that the serpentinite body can be mostly modelled as subvertical to steeply eastward dipping tabular bodies with a minimum depth extent of 1-3 km, although the modelling does not constrain the vertical extent. This is consistent with the modelling of the magnetic traverses extracted from aeromagnetic data. Sensitivity analysis of a tabular magnetic body reveals that a minimum susceptibility of 4000x10⁻⁶cgs is needed to generate the observed high amplitude anomalies of around 2000 nT, which is consistent with the susceptibility measurements of serpentinite samples along the Peel Fault ranging from 2000 to 9000 x 10⁻⁶ cgs. Rock magnetic study indicates that the serpentinite retains a strong remanence at some locations. This remanence is a viscous remanent magnetisation (VRM) which is parallel to the present Earth's magnetic field, and explains the large anomaly amplitude over the Peel fault at these locations. The remanence of serpentinite at other localities is not consistent enough to contribute to the observed magnetic anomalies. A much greater depth extent of the Peel Fault was inferred from gravity models. It is proposed that the serpentinite along the Peel Fault was emplaced as a slice of oceanic floor that has been accreted to the front of the arc, or as diapirs rising off the serpentinised part of the mantle wedge above the supra subduction zone.
Magnetic anomalies immediately east of the Mooki Fault once suggested to be produced by a dyke-like body emplaced along the fault were modelled along two ground magnetic traverses and three extracted aeromagnetic lines. Modelling results indicate that the anomalies can be modelled as an east-dipping overturned western limb of an anticline formed as a result of a fault-propagation fold with a shallow thrust step-up angle from the décollement. Interpretation of aeromagnetic data and modelling of the magnetic traverses indicate that the anomalies along the Mooki Fault are produced by the susceptibility contrast between the high magnetic Late Carboniferous Currabubula Formation and/or Early Permian volcanic rocks of the Tamworth Belt and the less magnetic Late Permian-Triassic Sydney-Gunnedah Basin rocks. Gravity modelling indicates that the Mooki Fault has a shallow dip ( ̃25°) to the east. Modelling of the five gravity profiles shows that the Tamworth Belt is thrust westward over the Sydney-Gunnedah Basin for 15-30 km. --The Meandarra Gravity Ridge within the Gunnedah Basin was modelled as a high density volcanic rock unit with a density contrast of 0.25 tm⁻³, compared to the rocks of the Lachlan Fold Belt in all profiles. The volcanic rock unit has a steep western margin and a gently dipping eastern margin with a thickness ranging from 4.5-6 km, and has been generally agreed to have formed within an extensional basin. --The Tamworth Belt, being mainly the product of volcanism of mafic character and thus has high density units, together with the high density Woolomin Association, which is composed chiefly of chert/jasper, basalt, dolerite and metabasalt, produces the Namoi Gravity High. Gravity modelling results indicate that the anomaly over the Tamworth Belt can be modelled as either a configuration where the Tablelands Complex extends westward underthrusting the Tamworth Belt, or a configuration where the Tablelands Complex has been thrust over the Tamworth Belt. When the gravity profiles were modelled with the first configuration, the Peel Fault with a depth extent of around 1 km can only be modelled for the Manilla and Quirindi profiles, modelling of the rest of the gravity profiles indicates that the Tablelands Complex underthrust beneath the Tamworth belt at a much deeper location.
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xi, 242 leaves ill., maps

It is widely believed that Australian Aboriginals utilised fire to manage various landscapes however to what extent this impacted on Australia???s ecosystems remains uncertain. The late Pleistocene/Holocene fire history from three sites within the Sydney Basin, Gooches Swamp, Lake Baraba and Kings Waterhole, were compared with archaeological and palaeoclimatic data using a novel method of quantifying macroscopic charcoal, which is presented in this study. The palynology and other palaeoecological proxies were also investigated at the three sites. The Gooches Swamp fire record appeared to be most influenced by climate and there was an abrupt increase in fire activity from the mid-Holocene perhaps associated with the onset of modern El Ni??o dominated conditions. The Kings Waterhole site also displayed an abrupt increase in charcoal at this time however there was a marked decrease in charcoal from ~3 ka. Lake Baraba similarly had displayed low levels of charcoal in the late Holocene. At both Kings Waterhole and Lake Baraba archaeological evidence suggests intensified human activity in the late Holocene during this period of lower and less variable charcoal. It is hence likely that at these sites Aboriginal people controlled fire activity in the late Holocene perhaps in response to the increased risk of large intense fires under an ENSO-dominated climate. The fire history of the Sydney Basin varies temporally and spatially and therefore it is not possible to make generalisations about pre-historic fire regimes. It is also not possible to use ideas about Aboriginal fire regimes or pre-historic activity as a management objective. The study demonstrates that increased fire activity is related to climatic variation and this is likely to be of significance under various enhanced Greenhouse scenarios. There were no major changes in the composition of the flora at all sites throughout late Pleistocene/Holocene although there were some changes in the relative abundance of different taxa. It is suggested that the Sydney Sandstone flora, which surrounds the sites, is relatively resistant to environmental changes. Casuarinaceae was present at Lake Baraba during the Last Glacial Maximum and therefore the site may have acted as a potential refugium for more mesic communities. There was a notable decline in Casuarinaceae during the Holocene at Lake Baraba and Kings Waterhole, a trend that has been found at a number of sites from southeastern Australia.

Alkalic porphyry style Au-Cu deposits of the Cadia district are associated with Late-Ordovician monzonite intrusions, which were emplaced during the final phase of Macquarie Arc magmatism at the end of the Benambran Orogeny. N-striking faults, including the curviplanar, northerly striking, moderately west-dipping basement thrust faults of the Cadiangullong system, developed early in the district history. NE-striking faults formed during rifting in the late Silurian. Subsequent E-W directed Siluro- Devonian extension followed by regional E-W shortening during the Devonian Tabberabberan Orogeny dismembered these intrusions, thereby superposing different levels porphyry Au-Cu systems as well as the host stratigraphy. During the late Silurian, the partially exhumed porphyry systems were buried beneath the Waugoola Group sedimentary cover sequence, which is generally preserved in the footwall of the Cadiangullong thrust fault system. The Waugoola Group is a typical rift-sag sequence, deposited initially in local fault-bounded basins which then transitioned to a gradually shallowing marine environment as local topography was overwhelmed. Basin geometry was controlled by pre-existing basement structures, which were subsequently inverted during the Devonian Tabberabberan Orogeny, offsetting the unconformity by up to 300m vertically. In the Waugoola Group cover, this shortening was accommodated via a complex network of minor detachments that strike parallel to major underlying basement faults. For this reason, faults and folds measured at the surface in the sedimentary cover can be used as a predictive tool to infer basement structures at depth.

This thesis concerns a sedimentological study of the Late Permian Broughton, Pheasants Nest and Erins Vale Formations, southern Sydney Basin, New South Wales, aimed at producing a palaeoenvironmental interpretation of these sequences. It is based on facies analysis of borecore data, vertical and lateral profiling of outcrop sequences, including architectural element analysis, and an integration of the results of these studies with previous work. The sequences studied begin with the interdigitating lower offshore silt of the upper Berry Siltstone and lower offshore sand-belt of the lower Broughton Formation, including progradational volcanic shoreface sequences. Sedimentation occurred in the 'Broughton Seaway' between the western cratonic landmass and a north-northeast oriented volcanic barrier in the east. River-derived meltwater underflows, massflows, tidally-driven longshore currents and migration of large sandwaves into the lower offshore sand-belt were the major depositional processes. The upper offshore sand-sheets of the middle Broughton Formation represent a widespread development of time-transgressive, above storm wave base, aggradational sedimentation. The progradational sandskirts of volcanic alluvial fans in the south (Jamberoo Sandstone Member) constructed a delta which was of a mixed type between a pyroclastic and alluvial fan delta. These kinds of deltas probably served as significant sources and depositional conduits for the offshore sediments which were dispersed mainly through wave action in a storm-dominated setting._ Submarine volcanic flows and associated shallow marine environments, and emerged volcanic islands with woodlands were coevally present in the southeast during the deposition of the Broughton Formation. The upper Broughton Formation is generally marked by a northeastward diachronous progradation of the southern shoreline, which progressively filled up the Broughton Seaway. Progradational evolution of the deltaic to barred shoreline, reflecting waning influence of the Gerringong volcanic barriers, was contemporaneous with the upper deltaic and distributary coastal zone sedimentation of the Pheasants Nest Formation. Actually, the periglacial braided subaerial fans and subaerial volcanism modelled for the lower and middle Pheasants Nest Formation greatly contributed to a northward progradation of the shoreline and retreat of the Broughton Seaway. With additional contributions from the western craton, a centripetal sediment transport pattern toward a northeast-oriented depocentre resulted. This meant development of a northeasterly flowing longitudinal drainage system. Physiographically, most of the former Broughton Seaway had now transformed into a broad valley between the volcanic and cratonic hinterlands. During the upper Pheasants Nest Formation time, extensive development of a flat, alluvial plain with an axial drainage pattern, low-lying coastal swamps and networks of high sinuosity, single channel or multiple channel anastomosing river systems is postulated. A shallow epeiric Erins Vale sea was caused by transgression across the topographically low-lying northeastern to northern alluvial plains of the Pheasants Nest Formation . The lower-middle Erins Vale Formation represents shoreface-offshore conditions in the east and north, including an oxygen-deficient, lower offshore regime (Kulnura Marine Tongue) - and shoreline fades of a transgressive barrier system in the west and south. Deposition during the upper Erins Vale Formation occurred through fan delta progradation from the western craton, which passed upward into the subaerial fan of the Marangaroo Conglomerate; a central and southern regressive barrier system and an energetic shoreface sand in the east which passed upward into the Wilton Formation. The upper Nowra Sandstone and lower Berry Siltstone form a transgressive systems tract. A sustained tectonic loading producing protracted subsidence was apparently the primary cause of basin subsidence. The upper Berry Siltstone and lower to middle Broughton Formation represent an overall highstand systems tract with portions of the upper Berry Siltstone and the lowest Broughton Formation showing interludes of minor transgressive pulses. This reflected a more stabilized base-level situation, following a reduction of basin subsidence rate. The upper Broughton Formation and lower-middle Pheasants Nest Formation constitute a lowstand systems tract, including early regressive phases represented by the upper Broughton Formation. It was related to the development of a foreswell on the basin margin and subsidence in the depocentre caused by the propagation of compressional energy from the orogen. The upper Pheasants Nest Formation indicates an early transgressive stage and the lower Erins Vale Formation, including the Kulnura Marine Tongue, is a transgressive systems tract. The middle Erins Vale Formation represents a highstand systems tract. Subsequently, the early regressive phases represented by the upper Erins Vale Formation, the lowstand wedge of the basal Wilton Formation and the Marangaroo Conglomerate constituted a lowstand systems tract. They developed as a result of erosion of a fores well produced on the cratonic margin. This study provides evidence in support of the Currarong Orogen. The Offshore Uplift is probably a preserved portion of the Currarong Orogen and the Newcastle Sub-basin was a likely depocentre for the Late Permian sequences. A periglacial climate with seasonal freezing and thawing had significant influence on sedimentation. Episodic meltwater discharge mobilized large volumes of volcaniclastic materials in spring (as lahars at times of large floods and/ or volcanic eruptions) and associated ice floes enroute to the sea. The major variables for the studied sequences in the southern Sydney Basin are constrained in this thesis, and comparative studies identified modern and ancient global examples that are broadly similar to the Late Permian sequences.

The Upper Nepean River catchment in the Sydney Basin has a rich repertoire of visual imagery - rock-art, and a variety of other types of marks on stone. This thesis examines the diversity and spatial distribution across the land of these rock markings and change over time. The theoretical focus is on materiality, practice and performance. In previous research conducted in the Sydney Basin, rock-art located in shelters has been considered, at least implicitly, to be functionally equivalent across both space and time. The research in this thesis, by comparison, has been developed to explore both synchronic and diachronic variability in sheltered rock-art and to give consideration to the occupational and contextual diversity this represents. The rock-art corpus is analysed in accordance with its material diversity in order to explore the qualitatively different forms of behavioural expression that this variation may embody. A fundamental distinction is made between graphically structured, imposed form on the one hand, and gestural marks on the other. The material relationship between the rock-art and the rock on and within which it is set, is also examined. The different data sets are explored dialectically and in accordance with their geographic and environmental location in order to gain an appreciation of the experience and engagement between Aboriginal people and the land in this part of the Sydney Basin. The analysis employs both quantitative and explicitly narrative approaches to examine the spatial and temporal dimensions of occupation. While this research has been conducted without the support of any direct dating or archaeological context, the methodology has, nevertheless allowed for the discrimination of temporal diversity in spatial patterns, and concomitantly, the manner in which the land has been occupied and created as landscape, over time. In order to achieve this, it has been crucial to analyse the rock markings not only in respect of their behaviour correlates, but also their material locations within geographic, environmental and micro-topographic space. The analysis of the Upper Nepean rock-art reveals a pattern of diachronic change in which the marking of the land with imagery became increasingly diverse in a number of formal and material ways, and geographically and environmentally common and widespread. The results suggests that regional bodies of rock-art are likely to have been produced in accordance with a diversity of motivations and functional purposes and that significant temporal change in the impetus to mark the land, and the choice of how and where to do so, can occur over relatively short time frames. It is argued that the practice of marking the land in the Upper Nepean was a dynamic dialectic, both constitutive and transformative, of being and place. Over time, people drew the land into an object world which became, with ever increasing inscription and embellishment, a marked and painted landscape, both productive of and reflecting, a complex history.

The Wybong Creek catchment is located in the upper Hunter Valley of New South Wales, Australia, and contains award winning beef and wine producing operations. Solute concentrations in Wybong Creek are often too high for irrigation use, however, with previous research showing that the saline and Na-Cl dominated water discharged from Wybong Creek decreases water quality in both the Goulburn and Hunter Rivers into which it flows. This study therefore aimed at identifying the source of solutes to the Wybong Creek catchment and the processes which cause salinisation of surface water, soil (regolith) and groundwater. Surface water was sampled at ten sites along Wybong Creek over three years, while groundwater was sampled from most of the bores and piezometers occurring in the Wybong Creek valley. Surface and groundwater in the upper catchment were dominated by Na-Mg-HCO3. Ratios of 87Sr/86Sr and cation/HCO3 indicated these facies were due to silicate weathering of the Liverpool Ranges, with localised groundwater bodies recharging in the Liverpool Ranges and discharging in the upper Wybong Creek valley. Wybong Creek became saline, and Na-Mg-Cl dominated in the mid-catchment area, with salinity doubling between the 55 and 60 km sample sites on some dates. Changes in surface water chemistry occurred independently of surface water input from tributaries, with abrupt salinity increases within a pool between these sites attributed to groundwater input via fractures beneath the Creek. One of two salt scalds in the Wybong Creek catchment also occurs adjacent to this stretch of river. A field site was established at the mid-catchment locality of Manobalai, therefore, in order to constrain the relationship between surface water, regolith and groundwater salinity. Ten piezometers were established at Manobalai, including three piezometer nests. Most regolith at Manobalai was found to be non-saline, including that within the salt scald, with the most saline and Na-Cl dominated regolith samples occurring in some of the most moist and coarse sandy/gravel layers. Groundwater sampled from piezometers installed in the holes drilled for regolith samples had salinities up to 20 times higher than the regolith on a per weight basis, and were similarly dominated by Na-Cl. A lack of carbonate and sulfate minerals within the soils and no indication of Ca-Mg/HCO3- SO4 dominated facies within alluvial soil solutions indicated groundwater did not evolve from rainwater to Na-Cl dominated facies while infiltrating the regolith. Groundwater samples from Manobalai were instead found to be amongst the most fresh and the most saline within the Wybong Creek catchment, and changed salinity abruptly down-gradient along a transect. Groundwater flow occurred through fractures in the Narrabeen Group sandstones and conglomerates, with vertical groundwater flow via fractures causing abrupt changes in salinity. Ratios of Na/Cl, Cl/Br and 87Sr/86Sr indicated saline groundwater at Manobalai and in the lower catchment was influenced by a marine endmember and halite dissolution. A poor relationship between salinity and d18O indicated this marine endmember was not evapoconcentrated rainwater. The occurrence of saline surface and groundwater in the Wybong Creek catchment was instead attributed to discharge from the regional groundwater system occurring in the Wittingham Coal Measures, with the abrupt increases in salinity at Manobalai indicating mixing between local, intermediate and/or regional groundwater systems. Salinity is likely to function similarly to this in the rest of the Hunter Valley also. The occurrence of salinity in both the Hunter River and Wybong Creek catchments is a naturally occurring phenomenon with salinity mitigation difficult due to the regional extent of the saline groundwater systems. Living with salt strategies are therefore recommended, such as limiting irrigation using both saline and fresh water and continuing with restrictions on saline discharge from coal mines.
This work was supported by ARC Linkage grant number LP05060743. Scholarship funding was provided by The Australian National University Faculty of Science and Research School of Earth Sciences, with project funding and support also provided by Hunter Central Rivers Catchment Management Authority and the New South Wales Office of Water.

The Hawkesbury River is the longest coastal river in New South Wales. A vital source of water and food, it has a long Aboriginal history and was critical for the survival of the early British colony at Sydney. The Hawkesbury’s weathered shores, cliffs and fertile plains have inspired generations of artists. It is surrounded by an unparalleled mosaic of national parks, including the second-oldest national park in Australia, Ku-ring-gai National Park. Although it lies only 35 km north of Sydney, to many today the Hawkesbury is a ‘hidden river’ – its historical and natural significance not understood or appreciated. Until now, the Hawkesbury has lacked an up-to-date and comprehensive book describing how and when the river formed, how it functions ecologically, how it has influenced humans and their patterns of settlement and, in turn, how it has been affected by those settlements and their people. The Hawkesbury River: A Social and Natural History fills this gap. With chapters on the geography, geology, hydrology and ecology of the river through to discussion of its use by Aboriginal and European people and its role in transport, defence and culture, this highly readable and richly illustrated book paints a picture of a landscape worthy of protection and conservation. It will be of value to those who live, visit or work in the region, those interested in Australian environmental history, and professionals in biology, natural resource management and education.

Abstract The Cadia district of New South Wales contains four alkalic porphyry Au-Cu deposits (Cadia East, Ridgeway, Cadia Hill, and Cadia Quarry) and two Cu-Au-Fe skarn prospects (Big Cadia and Little Cadia), with a total of ~50 Moz Au and ~9.5 Mt Cu (reserves, resources, and past production). The ore deposits are hosted by volcaniclastic rocks of the Weemalla Formation and Forest Reefs Volcanics, which were deposited in a submarine basin on the flanks of the Macquarie Arc during the Middle to Late Ordovician. Alkalic magmatism occurred during the Benambran orogeny in the Late Ordovician to early Silurian, resulting in the emplacement of monzonite intrusive complexes and the formation of porphyry Au-Cu mineralization. Ridgeway formed synchronous with the first compressive peak of deformation and is characterized by an intrusion-centered quartz-magnetite-bornite-chalcopyrite-Au vein stockwork associated with calc-potassic alteration localized around the apex of the pencil-like Ridgeway intrusive complex. The volcanic-hosted giant Cadia East deposit and the intrusion-hosted Cadia Hill and Cadia Quarry deposits formed during a period of relaxation after the first compressive peak of the Benambran orogeny and are characterized by sheeted quartz-sulfide-carbonate vein arrays associated with subtle potassic, calc-potassic, and propylitic alteration halos.