A tectonic mélange containing blueschists and eclogites, Middle Ordovician mid-ocean ridge basalt, cherts, and clastic sediments occurs at Port Macquarie in the southern New England Orogen, Australia. The clastics are quartz-poor and are dominated by mafic volcanic and fragmented plagioclase clasts; felsic volcanic clasts are less common. They exhibit erosional bases, graded bedding, load structures, and lithologies ranging from laminated mudstones to pebbly sandstones. Based on these features, they are interpreted as turbidites. During subduction, these turbidites were deformed and metamorphosed under prehnite–pumpellyite and lower greenschist facies conditions. Geochemically, they have a calc-alkaline, intra-oceanic arc signature; show no recycling; and have been derived from a provenance dominated by mafic volcanic rocks of basaltic-andesite composition. Further, chemical index of alteration (44–69) and Index of Compositional Variability (0.8–2.4) data reveal they show little weathering and are immature. The lack of weathering of rocks in a location where tropical climatic conditions existed is attributed to extreme erosion associated with a dynamic setting resulting in rapid transportation of the sediments to the fore arc basin and subsequently to the trench. As a consequence, little time was available for weathering to take place. The detritus in the turbidites is thought to have been derived from Late Ordovician volcanics in the Macquarie Arc and fore arc basin sequences of the Murrawong Formation. The cherts with which they are associated record both a continental and oceanic arc geochemical signature.

Logging data are measurements of physical properties of the formation surrounding a borehole, acquired in situ after completion of coring (wireline logging) or during drilling (Logging-While-Drilling, LWD). The range of data (resistivity, gamma radiation, velocity, density, borehole images,…) in any hole depends on the scientific objectives and operational constraints.

Logging data are measurements of physical properties of the formation surrounding a borehole, acquired in situ after completion of coring (wireline logging) or during drilling (Logging-While-Drilling, LWD). The range of data (resistivity, gamma radiation, velocity, density, borehole images,…) in any hole depends on the scientific objectives and operational constraints.

Logging data are measurements of physical properties of the formation surrounding a borehole, acquired in situ after completion of coring (wireline logging) or during drilling (Logging-While-Drilling, LWD). The range of data (resistivity, gamma radiation, velocity, density, borehole images,…) in any hole depends on the scientific objectives and operational constraints.

The fragmentary nature of the stratigraphic record is particularly evident with respect to fluvial deposits, which are characterized by a hierarchy of depositional units deposited over a wide range of time scales and sedimentation rates. We quantified stratigraphic completeness in meander-belt deposits through deducing the total area of bar sedimentation versus what is ultimately preserved in the depositional record, using area as a surrogate metric for sediment volume. Data sets were evaluated for a numerical model, the modern Mississippi River valley, and the Cretaceous McMurray Formation. In each data set, the evolutionary history of a series of meander-belt elements was discerned. Migrated area between successive reconstructed paleochannel positions was measured, representing: total area of net bar migration (MA), the area of bar preserved (PA), and percent of bar preserved (PA/MA), at the accretion package, bar, and meanderbelt scale. Results of our analysis show that the average preservation percent ranges from 27.3% to 67.8% for an accretion package, 35.0% to 85.1% for a bar, and 38.2% to 67.6% for a meander belt. The processes that lead to a decrease in preservation include intra-meanderbend erosion (due to downstream translation or bar rotation), and increasing meanderbend sinuosity and eventual cutoff (neck and chute), as well as inter-meander-bend erosion due to avulsion and subsequent migration of the meandering channel. The results of this study document a decrease in preservation over time that follows a natural logarithmic function of decay; we have termed this the “survivability” curve. The results presented here document a systematic, monotonic decrease in preservation over time, which is consistent regardless of the spatial or temporal scale and agrees with probabilities of preservation at long time scales proposed by previous workers. A comparison between data sets allows for an estimation of the time span represented by meander-belt deposits in the deep time record.

The three-dimensional reconstruction of meander-belt deposits from ancient strata provides insight into the formative processes of meander-bend evolution and paleogeographic interpretations. A significant challenge to such analyses is limited exposures in outcrop belts and widely spaced or sparse subsurface datasets. An unprecedented dataset consisting of 600 km(2) of 3-D seismic data and over 1000 well penetrations from the Cretaceous McMurray Formation in northeastern Alberta, Canada, provides a unique opportunity to characterize an ancient continental-scale river system. Paleochannels ranged from 475 to 1180 m wide and from 35 to 50 m deep, with meander-belt width-to-thickness ratios between 107:1 and 401:1. The data reveal evidence for intra-point-bar erosion and punctuated rotation, counter-point-bar development, and protracted channel cut-off and meander-loop abandonment. Observations enable interpretation of morphodynamic processes that are commonly observed in modern systems, yet rarely described from the rock record.A 3-D geocellular model and reconstructed paleochannel migration patterns reveal the evolutionary history of seventeen individual meander belt-elements, including point bars, counter-point bars, and their associated abandoned channel fills, which have been mapped using core, FMI logs, and seismic data. Results of the study show that intra-point-bar erosion surfaces bound accretion packages characterized by unique accretion directions, internal stratigraphic architecture, and lithologic properties. We provide evidence for channel-belt-edge confinement and development of a counter-point bar, as well as the deposition of side bars and preservation of a mid-channel bar during meander-bend abandonment. Analysis of changes in meander-belt morphology over time reveal a decrease in channel-belt width/thickness ratio and sinuosity, which we compare with observations from the lower Mississippi River and attribute to the landward migration of the paleo-backwater limit due to transgression of the Cretaceous Boreal Sea into the Alberta foreland basin.

ABSTRACT Sedimentological and accelerator mass spectrometry (AMS) 14C data provide estimates of the structure and age of five submarine landslides (∼0.4–3 km3) present on eastern Australia's continental slope between Noosa Heads and Yamba. Dating of the post-slide conformably deposited sediment indicates sediment accumulation rates between 0.017 m ka–1 and 0.2 m ka–1, which is consistent with previous estimates reported for this area. Boundary surfaces were identified in five continental slope cores at depths of 0.8 to 2.2 m below the present-day seafloor. Boundary surfaces present as a sharp colour-change across the surface, discernible but small increases in sediment stiffness, a slight increase in sediment bulk density of 0.1 g cm–3, and distinct gaps in AMS 14C ages of at least 25 ka. Boundary surfaces are interpreted to represent a slide plane detachment surface but are not necessarily the only ones or even the major ones. Sub-bottom profiler records indicate that: (1) the youngest identifiable sediment reflectors upslope from three submarine landslides terminate on and are truncated by slide rupture surfaces; (2) there is no obvious evidence for a post-slide sediment layer draped over, or burying, slide ruptures or exposed slide detachment surfaces; and (3) the boundary surfaces identified within the cores are unlikely to be near-surface slide surfaces within an overall larger en masse dislocation. These findings suggest that these submarine landslides are geologically recent (<25 ka), and that the boundary surfaces are either: (a) an erosional features that developed after the landslide, in which case the boundary surface age provides a minimum age for the landslide; or (b) detachment surfaces from which slabs of near-surface sediment were removed during landsliding, in which case the age of the sediment above the boundary surface indicates the approximate age of landsliding. While an earthquake-triggering mechanism is favoured for the initiation of submarine landslides on the eastern Australian margin, further evidence is required to confirm this interpretation.

Carbon cycling on the east coast of Australia has the potential to be strongly affected by El Niño-Southern Oscillation (ENSO) intensification and coastal development (industrialization and urbanization). We performed paleoreconstructions of estuarine sediments from a seagrass-dominated estuary on the east coast of Australia (Tuggerah Lake, New South Wales) to test the hypothesis that millennial-scale ENSO intensification and European settlement in Australia have increased the transfer of organic carbon from land into coastal waters. Our data show that carbon accumulation rates within coastal sediments increased significantly during periods of maximum millennial-scale ENSO intensity ("super-ENSO") and coastal development. We suggest that ENSO and coastal development destabilize and liberate terrestrial soil carbon, which, during rainfall events (e.g., La Niña), washes into estuaries and becomes trapped and buried by coastal vegetation (seagrass in this case). Indeed, periods of high carbon burial were generally characterized as having rapid sedimentation rates, higher content of fine-grained sediments, and increased content of wood and charcoal fragments. These results, though preliminary, suggest that coastal development and ENSO intensification—both of which are predicted to increase over the coming century—can enhance capture and burial of terrestrial carbon by coastal ecosystems. These findings have important relevance for current efforts to build an understanding of terrestrial-marine carbon connectivity into global carbon budgets.

We investigated the Holocene palaeo-environmental record of the Tuggerah Lake barrier estuary on the south-east coast of Australia to determine the influence of local, regional and global environmental changes on estuary development. Using multi-proxy approaches, we identified significant down-core variation in sediment cores relating to sea-level rise and regional climate change. Following erosion of the antecedent land surface during the post-glacial marine transgression, sediment began to accumulate at the more seaward location at ∼8500years before present, some 1500years prior to barrier emplacement and ∼4000years earlier than at the landward site. The delay in sediment accumulation at the landward site was a consequence of exposure to wave action prior to barrier emplacement, and due to high river flows of the mid-Holocene post-barrier emplacement. As a consequence of the mid-Holocene reduction in river flows, coupled with a moderate decline in sea-level, the lake experienced major changes in conditions at ∼4000years before present. The entrance channel connecting the lake with the ocean became periodically constricted, producing cyclic alternation between intervals of fluvial- and marine-dominated conditions. Overall, this study provides a detailed, multi-proxy investigation of the physical evolution of Tuggerah Lake with causative environmental processes that have influenced development of the estuary.

Meander belts are characterized by a complex amalgam of point bars and associated depositional elements, such as oxbow-lake fills. Point-bar deposits are composite elements often characterized by complex scroll-bar patterns formed in response to processes of expansion, rotation, and translation of a meander bend. Intra-point-bar erosion is commonly observed in modern river systems, yet its product is rarely described from the ancient record. Late Cretaceous meander-belt deposits, consisting of a transition from a point-bar to counter-point-bar deposit, as well as an associated abandoned channel fill, crop out in south central Alberta, Canada. The strata are characterized by widespread evidence for intra-point bar deposit erosion and punctuated rotation.In the stratigraphic record, intra-point bar deposit erosion and punctuated rotation is expressed by steeply dipping discordant surfaces (up to 20 degrees), which truncate previously deposited lateral-accretion packages. Across these erosion surfaces the direction of bar migration often rotates significantly, up to 50 degrees. Subsequent accretion surfaces onlap intra-point-bar-deposit erosion surfaces.The analysis reveals that point-bar surfaces are formed through a complex interplay of erosional and depositional processes along their length, resulting in stratigraphic surfaces that may be highly composite. This study departs from more simplistic process models of point bars that consider deposits to be the product of continuous lateral accretion, and as such has important implications for paleoenvironmental reconstructions and subsurface reservoir characterization.

Morphologic characterisation of five distinct, eastern Australian upper continental slope submarine landslides enabled modelling of their tsunami hazard. Flow depth, run-up and inundation distance has been calculated for each of the five landslides. Future submarine landslides with similar characteristics to these could generate tsunami with maximum flow depths ranging 5-10 m at the coastline, maximum run-up of 5 m and maximum inundation distances of 1 km.

Port Stephens, located in SE Australia, is a shallow estuary with an outer and inner basin separated by a narrow channel. Foraminiferal biofacies distribution reveals this complex physical environment. The flood-tide delta forms a transition between the wave-dominated open coast and the microtide-dominated estuary. Sand wave dynamics cause a shifting substrate, resulting in allochthonous assemblages of calcareous shelf species transported into the bay through a wide entrance. The muddy central basin is heavily bioturbated, and allows for an in-situ, mixed calcareous and agglutinated assemblage of a progressively more estuarine character. Burial of organic matter and increased bioturbation permits infaunal species to increase in abundance, but promotes calcium carbonate dissolution. The bayhead delta of the Karuah River is characterized by lithic-rich substrates that are associated with robust calcareous species. Tidal cycles, combined with low river-flux, provide nearly fully marine conditions far upstream into the Karuah River. Marginal regions, from sandy/muddy tidal flats to marsh, show distinct assemblages of opportunistic species that respond to tidal exposure, substrate variations, organic matter flux and salinities. Early diagenetic taphonomic loss, closely linked with bioturbation, needs to be considered in interpretations of microfossil assemblages. Foraminiferal biofacies analysis, in combination with the brackish-water ichnology model, is a powerful tool for recognizing Mesozoic marginal marine environments. Port Stephens, with its environmental complexity, offers a valuable modern analogue for estuarine deposits of the geological past.

Sequence stratigraphy and coal cycles based on accommodation trends were investigated in the coal-bearing Lower Cretaceous Mannville Group in the Lloydminster heavy oil field, eastern Alberta. The study area is in a low accommodation setting on the cratonic margin of the Western Canada sedimentary basin. Geophysical log correlation of coal seams, shore-face facies, and the identification of incised valleys has produced a sequence-stratigraphic framework for petrographic data from 3 cored and 115 geophysical-logged wells. Maceral analysis, telovitrinite reflectance, and fluorescence measurements were taken from a total of 206 samples. Three terrestrial depositional environments were interpreted from the petrographic data: ombrotrophic mire coal, limnotelmatic mire coal, and carbonaceous shale horizons. Accommodation-based coal (wetting- and drying-upward) cycles represent trends in depositional environment shifts, and these cycles were used to investigate the development and preservation of the coal seams across the study area.The low-accommodation strata are characterized by a high-frequency occurrence of significant surfaces, coal seam splitting, paleosol, and incised-valley development. Three sequence boundary unconformities are identified in only 20 m (66 ft) of strata. Coal cycle correlations illustrate that each coal seam in this study area was not produced by a single peat-accumulation episode but as an amalgamation of a series of depositional events. Complex relations between the Cummings and Lloyd-minster coal seams are caused by the lateral fragmentation of strata resulting from the removal of sediment by subaerial erosion or periods of nondeposition. Syndepositional faulting of the underlying basement rock changed local accommodation space and increased the complexity of the coal cycle development.This study represents a low-accommodation example from a spectrum of stratigraphic studies that have been used to establish a terrestrial sequence-stratigraphic model. The frequency of changes in coal seam quality is an important control on methane distribution within coalbed methane reservoirs and resource calculations in coal mining. A depositional model based on the coal cycle correlations, as shown by this study, can provide coal quality prediction for coalbed methane exploration, reservoir completions, and coal mining.

This chapter contains sections titled: Introduction Stratigraphic/Structural Setting Early-Rift Evolution (Permo-Triassic): the Initial Split of Gondwana Jurassic Rifi-Drift Transition Initial (Late Jurassic) Breakup North of the Exmouth Plateau Neocomian Late-Rift Deltaic Sedimentation at the Central Exmouth Plateau and the Final Separation between Australia and Greater India Late Aptian-Alblan Evolution Mature Ocean Evolution (Late Cretaceous and Younger) Discussion Conclusions

The southeast Australian passive continental margin is narrow, steep and sediment-deficient, and characterized by relatively low rates of modern sedimentation. Upper slope (<1,200 m) sediments comprise mixtures of calcareous and terrigenous sand and mud. Three of twelve sediment cores recovered from geologically-recent, submarine landslides located offshore New South Wales/Queensland (NSW/QLD) are interpreted to have sampled failure surfaces at depths of between 85 and 220 cm below the present-day seabed. Differences in sediment physical properties are recorded above and below the three slide-plane boundaries. Sediment taken directly above the inferred submarine landslide failure surfaces and presumed to be post-landslide, returned radiocarbon ages of 15.8, 20.7 and 20.1 ka. The last two ages correspond to adjacent slide features, which are inferred to be consistent with their being triggered by a single event such as an earthquake. Slope stability models based on classical soil mechanics and measured sediment shear-strengths indicate that the upper slope sediments should be stable. However, multibeam sonar data reveal that many upper slope landslides occur across the margin and that submarine landsliding is a common process. We infer from these results that: (a) an unidentified mechanism regularly acts to reduce the shear resistance of these sediments to the very low values required to enable slope failure, and/or (b) the margin experiences seismic events that act to destabilise the slope sediments.

This paper describes LG-PACKAGE, a set of the Linguistic Geometry (LG) tools. LG is a type of game theory that is scalable to the level of the real world defense systems. The LG applications generate best strategies for all sides in a conflict in real time. We consider the main advanced features of the versions of LG-PACKAGE released gradually from 2004 through 2012. These releases converted LG-PACKAGE into the software of industrial strength applicable to the wide range of defense systems. The US and British defense agencies and the world major defense contractors utilize these tools.

Analysis of sand-body distribution reveals that fluvial channel sands in the Upper Cretaceous lower Williams Fork Formation in the central Piceance Basin, Colorado, USA, are not randomly distributed but are predictable in their spatial and stratigraphic position. Sand bodies are organized in channel-belt clusters that are compensationally stacked on different temporal scales. While channel clustering occurred over a shorter period (channel and channel-belt scale 1 Os ky to 100s ky), compensational stacking occurred over a much longer time scale (channel cluster belts, similar to 400 ky).The lower Williams Fork Formation consists of three distinct intervals of clustered channel belts, each similar to 400 ft (similar to 122 m) thick, topped by a thin coal layer. The primary control on the cluster formation is autogenic channel avulsion during an overall aggradational phase. Short-lived changes in in basin accommodation caused by either changes in tectonic subsidence or high-frequency eustatic changes due to Milankovitch-band orbital forcing at the end of each cluster interval result in a distinct increase in channel thickness and coal formation towards the end of each cycle.Coals at the end of each sub-cluster span the entire study area, but their overall thickness is greater in the inter-cluster, floodplain-prone areas. The resulting differential early coal compaction is greatest in the inter-cluster areas and has a significant control on the subsequent cluster-belt position overlying the coal. Channel sands overlying the coals are concentrated in the previously low net/gross floodplain-prone inter-cluster areas resulting in compensationally stacked cluster belts. On the longest time scale (similar to 1 to 1.5 My), which encompasses the entire lower Williams Fork, changes in channel geometries and sand-body thickness seem to be controlled mainly by long-term changes in eustasy, and autogenic processes are of lesser importance.