Stratigraphy and development of the Late Miocene-Early Pleistocene Hawke’s Bay forearc basin

A Late Miocene-Early Pleistocene mixed carbonate-siliciclastic sedimentary succession about 2 500 m thick in the Hawke’s Bay forearc basin is the focus of a basin analysis. The area under investigation covers 3 500 km2 of western and central Hawke’s Bay. The stratigraphy of Hawke’s Bay Basin is characterised by dramatic vertical and lateral facies changes and significant fluxes of siliciclastic sediment through the Late Miocene and Pliocene. This project aims to better understand the character and origin of the sedimentary succession in the basin. Geological mapping has been undertaken at a scale of 1:25000, with data managed in an ARCINFO geodatabase, following the database model employed in the IGNS QMap programme. Along the western margin of the basin there is progressive southward onlap of late Cenozoic strata on to basement. The oldest units are of Late Miocene (Tongaporutuan) age and the youngest onlap units are of latest Pliocene (Nukumaruan) age. Geological mapping of the basin fill places constraints on the magnitude (about 10 km) and timing (Pleistocene) of most of the offset on the North Island Shear Belt. Lithofacies have been described and interpreted representing fluvial, estuarine, shoreface and inner- to outer-shelf environments. Conglomerate facies are representative of sediment-saturated prograding fluvial braidplains and river deltas. These units are dominated by greywacke gravels and record the erosion of the Kaweka-Ahimanawa Ranges. Sandstone facies typically comprise very well sorted, clean non-cemented units of 10-50 m thickness that accumulated in innershelf environments. Siltstone facies probably accumulated in relatively quiet, middle- to outer-shelf water depths, and comprise well-sorted, firm non-cemented units with occasional tephra interbeds. Limestone facies represent examples of continent-attached cool-water carbonate systems that developed in response to strong tidal currents and a high nutrient flux during the Pliocene. These facies are examples of mixed siliciclastic-bioclastic sedimentary systems. Of these facies the widespread distribution and thickness of sandstone and limestone units present the most potential for hydrocarbon reservoirs. Similarly, the distribution of siltstone and mudstone beds provides adequate seal rocks. Mangapanian limestone facies have already been targeted as potential petroleum reservoirs (e.g. Kereru-1). Geological mapping suggests that potential hydrocarbon reservoir and seal rocks occur extensively in the subsurface

Systematic lithostratigraphy of the Neogene succession exposed in central parts of Hawke’s Bay Basin, eastern North Island, New Zealand

This report presents a systematic lithostratigraphy for the Neogene (Miocene–Recent) sedimentary succession in central parts of Hawke’s Bay Basin in eastern North Island, New Zealand. It has been built up chiefly from strata exposed in outcrop, but petroleum exploration drill hole data have also been incorporated to produce this stratigraphic synthesis. Most of the strata exposed in this part of the basin are of Late Miocene (Tongaporutuan, local New Zealand Stage) to Recent age, and the majority of this report focuses on these starta, with brief description of Middle and Early Miocene formations. A companion PR report (Kamp et al. 2007) contains stratigraphic columns for sections through the Neogene succession described in this report

Gravitational wave background in perfect fluid quantum cosmologies

We discuss the gravitational wave background produced by bouncing models based on a full quantum evolution of a universe filled with a perfect fluid. Using an ontological interpretation for the background wave function allows us to solve the mode equations for the tensorial perturbations, and we find the spectral index as a function of the fluid equation of state.Comment: 12 pages, 5 figures, to appear in Phys. Rev. D (2006

Late Miocene – Early Pleistocene paleogeography of the onshore central Hawke’s Bay sector of the forearc basin, eastern North Island, New Zealand, and some implications for hydrocarbon prospectivity

The timing of trap formation in relation to the timing of source rock burial and maturation are important considerations in evaluating the hydrocarbon prospectivity of onshore parts of the forearc basin in central Hawke’s Bay. We describe here aspects of the Late Miocene to Early Pleistocene paleogeography for the area based on detailed field mapping and lithofacies analysis, to help constrain petroleum systems evaluations. Key conclusions are: • Most deformation of the forearc basin fill appears to be relatively young (i.e. post-2 Ma). This deformation has occurred after a major phase of Late Miocene to Pliocene sediment accumulation, and is particularly significant along the northwestern and southeastern margins of the basin. • The axis of the forearc basin in central Hawke’s Bay appears to have undergone little structural deformation. Gentle force and reverse faults in the subsurface may be suitable traps. • The most widespread potential reservoir beds are Miocene sandstone beds. • Potential hydrocarbon source rocks are mostly absent from western parts of the basin due to significant Neogene uplift and erosion. They are, however, probably still widely preserved beneath central parts of the basin where uplift and erosion have been much less pronounced. • Miocene structures within the axis of the basin, buried by the Late Miocene to Pleistocene siliciclastic succession, are likely exploration targets. The forearc basin has been substantially inverted along its western side since the latest Pliocene, resulting in erosion of older sediments, including potential source rocks, down to basement in ranges flanking its western side. The stratigraphy along the eastern margin of the forearc basin, and particularly the outcrop pattern of westward-younging Plio-Pleistocene limestones, records the development of faulting and folding associated with the elevation and growth of the inboard part of the accretionary wedge. Parts of the forearc basin succession have become involved in the accretionary wedge, which has migrated westward through time. Uplift of the inboard margin of the accretionary wedge since the latest Miocene helped to cause an interior seaway to develop to the west during the Pliocene. Distinctive coarse-grained bioclastic carbonate sediments of the Te Aute lithofacies were deposited along both margins of the seaway, which was most extensive during the Late Pliocene (Mangapanian). Although significant volumes of siliciclastic sediment were supplied to the basin during the Pliocene, strong tidal currents periodically swept much of these sediments northeastward. Tidal connections existed during the Pliocene into Wanganui Basin in the vicinity of Kuripapango and Manawatu Gorge. By the latest Pliocene (lower Nukumaruan), the interior seaway became closed in the south with uplift of the Mount Bruce block in northern Wairarapa. Potential reservoirs within the map area include both shelf and redeposited sandstone beds in the Miocene to Early Pliocene Tolaga Group. Thick, coarse-grained, variably cemented Plio-Pleistocene limestone lithofacies in the Mangaheia Group are widespread along the margins of the basin, and have been the targets for several past exploration programmes. However, drilling has shown that the attractiveness of the Pliocene limestone facies as reservoir beds is limited because they quickly pass laterally into siliciclastic mudstone away from the margins of the basin

An Access Control Model for Protecting Provenance Graphs

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Spin physics with STAR

The STAR collaboration aims to study polarized proton-proton collisions at RHIC. The emphasis of the spin run this year is on transverse single spin asymmetries. Beyond 2001, we aim to determine directly and precisely the gluon polarization, as well as the polarizations of the u, $\bar{u}$, d and $\bar{d}$ quarks in the proton by measuring in addition longitudinal and double spin asymmetries. Furthermore, we aim to measure for the first time the quark transversity distributions. These measurements will improve substantially the knowledge and understanding of the spin structure of the nucleon.Comment: 9 pages, 3 figures. Talk presented at The 3rd Circum-Pan-Pacific Symposium on "High Energy Spin Physics" October 8-13 2001, Beijing, Chin

Perturbations in the Ekpyrotic Scenarios

With the new cosmological data gathered over the last few years, the inflationary paradigm has seen its predictions largely unchallenged. A recent proposal, called the ekpyrotic scenario, was argued to be a viable competitor as it was claimed that the spectrum of primordial perturbations it produces is scale invariant. By investigating closely this scenario, we show that the corresponding spectrum depends explicitly on an arbitrary function of wavenumber and is therefore itself arbitrary. It can at will be set scale invariant. We conclude that the scenario is not predictive at this stage.Comment: 4 pages, no figure, uses moriond.sty, to appear in the proceeding of the Moriond cosmology meeting held at Les Arcs, France (March 16-23, 2002

Mangarara Formation: exhumed remnants of a middle Miocene, temperate carbonate, submarine channel-fan system on the eastern margin of Taranaki Basin, New Zealand

The middle Miocene Mangarara Formation is a thin (1–60 m), laterally discontinuous unit of moderately to highly calcareous (40–90%) facies of sandy to pure limestone, bioclastic sandstone, and conglomerate that crops out in a few valleys in North Taranaki across the transition from King Country Basin into offshore Taranaki Basin. The unit occurs within hemipelagic (slope) mudstone of Manganui Formation, is stratigraphically associated with redeposited sandstone of Moki Formation, and is overlain by redeposited volcaniclastic sandstone of Mohakatino Formation. The calcareous facies of the Mangarara Formation are interpreted to be mainly mass-emplaced deposits having channelised and sheet-like geometries, sedimentary structures supportive of redeposition, mixed environment fossil associations, and stratigraphic enclosure within bathyal mudrocks and flysch. The carbonate component of the deposits consists mainly of bivalves, larger benthic foraminifers (especially Amphistegina), coralline red algae including rhodoliths (Lithothamnion and Mesophyllum), and bryozoans, a warm-temperate, shallow marine skeletal association. While sediment derivation was partly from an eastern contemporary shelf, the bulk of the skeletal carbonate is inferred to have been sourced from shoal carbonate factories around and upon isolated basement highs (Patea-Tongaporutu High) to the south. The Mangarara sediments were redeposited within slope gullies and broad open submarine channels and lobes in the vicinity of the channel-lobe transition zone of a submarine fan system. Different phases of sediment transport and deposition (lateral-accretion and aggradation stages) are identified in the channel infilling. Dual fan systems likely co-existed, one dominating and predominantly siliciclastic in nature (Moki Formation), and the other infrequent and involving the temperate calcareous deposits of Mangarara Formation. The Mangarara Formation is an outcrop analogue for middle Miocene-age carbonate slope-fan deposits elsewhere in subsurface Taranaki Basin, New Zealand

Azimuthal and pseudo-rapidity correlations with strange particles at intermediate-pT_T at RHIC

We present results on two-particle azimuthal correlations with strange trigger particles ($K^0_S$, $\Lambda$, $\Xi$, $\Omega$) associated with unidentified charged particles %at intermediate $p_T$ in d+Au and Au+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV. We investigate, in detail, the near-side associated yield as a function of centrality, $p_T$ and strangeness content in the trigger particle to look for possible flavor and baryon/meson differences. We compare our results to a fragmentation and recombination model, where the study of $\Omega$-triggered correlations is used as a critical test of the validity of the recombination picture.Comment: 4 pages, 3 figures, presented at the 19th International Conference on Ultra-Relativistic Nucleus-Nucleus Collisions, "Quark Matter 2006", Shanghai, China, November 14-20, 200

Intra-jet correlations of high-ptp_t hadrons from STAR

Systematic measurements of pseudorapidity ($\Delta\eta$) and azimuthal ($\Delta\phi$) correlations between high-$p_t$ charged hadrons in $\sqrt{s_{NN}}$=200 GeV Au+Au collisions are presented. An enhancement of correlated yield at large $\Delta\eta$ on the near-side is observed. This effect persists up to trigger $p_{t}^{trig}$ $\sim$ 9 GeV/c, indicating that it is associated with jet production. More detailed analysis suggests distinct short-range and long-range components in the correlation.Comment: 4 pages, 5 figures, presented at the 19th International Conference on Ultra-Relativistic Nucleus-Nucleus Collisions, "Quark Matter 2006", Shanghai, China, November 14-20, 200