50thKaikoura05 -1- Kaikoura 2005 CHARACTERISATION OF NEW ...

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indicates pressures of ca. 10-12kbar during aureole development in Wet Jacket Arm. Amphibolite facies assemblages remain outside the aureole indicating that equilibration to granulite facies assemblages only occurred within the immediate vicinity of the Malaspina Gneiss suggesting reaction kinetics were an important control on the extent to which granulite facies assemblages developed in country rocks intruded by the WFO. ORAL LATE NEOGENE BARNACLE-RICH LIMESTONES, MATAPIRO-OMAHU, HAWKE’S BAY: THEIR LIFE FROM DEPOSITION TO UPLIFT R.A. Baggs 1,2 ,C.S.Nelson 2 , P.J.J. Kamp 2 ,K.J. Bland 2 & S.D. Hood 2 1 CRL Energy Ltd. P.O. Box 290, Greymouth 2 Dept of Earth Sciences, University of Waikato, Private Bag 3105, Hamilton (rachelbaggs_nz*hotmail.com) A new GIS-based 1:40,000 scale geological map has been produced for the Matapiro-Omahu region, between the Tutaekuri and Ngaruroro Rivers, west of Napier city in eastern North Island. The rocks occupy the southern part of the regional Matapiro Syncline, are of late Pliocene-early Pleistocene age (Nukumaruan), are contained within the Petane Group, and comprise a cyclothemic succession of formations of terrigenous mudstone and limestone, with some conglomerate. The three limestone units, in ascending order the Tangoio Limestone, Matapiro Limestone and Puketautahi Limestone, tend to stand proud in the landscape and provide good mappable horizons, while the intervening mudstones are poorly exposed. The Tangoio Limestone is restricted to the eastern limb of the Matapiro Syncline and grades to fossiliferous greywacke gravels (Sherenden Conglomerate Member) towards the west. The pebbly Matapiro Limestone is distributed throughout the southern part of the syncline, while the Puketautahi Limestone caps the hills on the western limb. Sedimentological and petrographic analyses of the three limestones indicate that they are all barnacledominated with an increasing proportion of bivalve material up through the units, and with small amounts of bryozoans, echinoderms, benthic foraminifera, and occasional serpulids and red algae. Skeletal grains are commonly microbored. The rocks are mainly skeletal grainstones, less commonly skeletal packstones, and carbonate contents average 70-80%. Cements involve a variety of calcite spar fabrics, including syntaxial rim, isopachous fringe, meniscus and equant types, usually non-ferroan and with non- to dull cathodoluminescence. The spar cements were precipitated during shallowest burial (likely no more than about 200 m), involving mild pressuredissolution of skeletons, and during subsequent uplift when dissolution of aragonitic shells provided a later stage of equant and micro-equant cement. Most of the limestones retain moderate porosity in outcrop. The skeletal composition is consistent with deposition of all three limestones in a similar high energy, current swept seaway environment (Ruataniwha Strait) at inner shelf depths. Deposition was associated with rapidly transgressing seas coupled with low terrigenous sediment supply, forming relatively thin transgressive systems tract (TST) carbonate deposits. Highstand systems tract (HST) deposits are represented by the intervening, thicker, midshelf mudstones, which accumulated over longer durations than the limestones. Four major cyclothems (TST + HST) are identified for the mapped succession, the depositional settings being primarily controlled by glacio-eustatic sea level fluctuations near the opening of the Ruataniwha Strait into Hawke Bay in the Nukumaruan, during a period of slow basin subsidence followed eventually by uplift and exhumation of the whole succession. ORAL FISH, FRUSTULES, FRUITS, A FLOWER - AND LOTS OF LEAVES: AN INVESTIGATION INTO THE BIOTA OF AN EARLY MIOCENE MAAR LAKE J.M. Bannister 1 &D.E.Lee 2 1 Departments of Botany & Geology, University of Otago, PO Box 56, Dunedin 2 Department of Geology, University of Otago, PO Box 56, Dunedin (jmb*clear.net.nz) Preliminary findings from a finely varved diatomite deposit formed during the Early Miocene in a maar lake near Middlemarch, Otago are presented. The varves are alternately dark and light and the light coloured layers are made up almost entirely of diatom frustules with some freshwater sponge spicules. The diatom flora is overwhelmingly dominated by a single species, Encyonema jordanii (Grunow) Mills. The sponge(s) probably encrusted plant material such as stems of water plants and dead leaves. Limited excavations in the upper few metres of the deposit have yielded several entire fish skeletons up to 15 cm long that belong to a new species of galaxiid. The diatomite contains numerous fruits and seeds in different states of preservation; these are mainly small and difficult to identify, but some of the larger fruits may be 50 th Kaikoura05 -2- Kaikoura 2005
myrtaceous. One 20 mm diameter flower, Fouldenia staminosa Bannister, D.E.Lee and Raine, 2005, was preserved complete with anthers from which excellently preserved pollen was collected and preparations made for both light and electron microscopy. Identification of pollen and spores from the matrix on the same bedding plane as the flower produced a list of more than 55 pollen types, including new taxa (Bannister et al. 2005). Angiosperm leaves are numerous; those collected from the layers of diatom frustules are better preserved than those from darker, more organic layers and we surmise that mucus from the vast numbers of diatoms has assisted in preservation of the leaf material. Some leaves have both upper and lower surface cuticles present and cuticle preparations for over 150 individual leaves representing several families and genera, some with close affinities to extant genera, have been made. The leaves appear to be mainly from forest trees and lianes with moderately thick cuticles; as yet no herbaceous leaves or examples of leaves with thin cuticles have been found. Leaf venation is not always visible but various methods for clearing leaves to expose venation, and methods of leaf preservation, have been developed. A database incorporating cuticular features and leaf architecture is being compiled together with a reference collection of cuticles from extant trees and lianes from both New Zealand and Australia. Bannister, J.M., Lee, D.E., & Raine, J.I. 2005: Morphology and palaeoenvironmental context of Fouldenia staminosa, a fossil flower with associated pollen from the Early Miocene of Otago, New Zealand. New Zealand Journal of Botany 43: 515-525 ORAL TECTONIC EVOLUTION OF THE SOUTH FIJI BASIN: UNCLOS HELPS TACKLE REGIONAL TECTONICS D. Barker 1 ,R.Herzer 1 ,N.Mortimer 2 ,W.Roest 3 , A. Mauffret 4 & Y. Lafoy 5 1 GNS Science, P.O. Box 30368, Lower Hutt, New Zealand 2 GNS Science, Private Bag 1930, Dunedin, New Zealand 3 IFREMER, Géosciences Marines, 29280 Plouzané, BP 70, France 4 Lab. Tectonique Univ. P. et M. Curie, 4 Place Jussieu, 75256 Paris Cedex, France 5 ServicedelaGéologieetdesMines(SGM), DIMENC, Nouméa, New Caledonia (d.barker*gns.cri.nz) Marine surveys to study the evolution of remnant arcs and backarc basins north of New Zealand have been complemented by United Nations Convention on the Law of the Sea (UNCLOS) surveys by three countries – France, New Zealand and Australia – with potential extended continental shelf claims in the region. The UNCLOS factor allowed 9 cruises to focus on the region in the past 9 years, collecting approximately 30,000 km of seismic reflection (5,000 deep crustal), 263,700 sq km of swath bathymetry, and 70 dredge samples. Feedback through sharing or publishing data and joint participation allowed efficient planning and deployment of academic and UNCLOS cruises. Two models for South Fiji and Norfolk basin evolution arise from current studies: at the level of the Three Kings Ridge – Norfolk Basin – southern South Fiji Basin both involve Pacific trench rollback and southward propagating spreading, but one also uses two subduction systems and arc-continent collision. Linked spreading of the Norfolk Basin and South Fiji Basin is invoked in both models, but the veracity and geodynamics of the link are not investigated. A growing body of petrological and radiometric evidence and the tectonics of the New Zealand continental margin point to tandem Early Miocene spreading of the South Fiji Basin and Norfolk Basin despite published magnetic interpretations that would confine South Fiji Basin spreading to the Oligocene. The Franco-NZ NOUCAPLAC-1 cruise, the last cruise relevant to UNCLOS in this region, included a scientific objective to investigate the South Fiji Basin– Norfolk Basin link in the critical area bounded by the Loyalty Ridge, the Cook Fracture Zone, the Bounty spreading centre and the Julia Lineament with swath mapping, magnetics and seismic reflection. Initial results show a complex bathymetry where a possible link between the Bounty spreading centre and the Cook Fracture Zone involves ridge propagation, overlapping spreading centres, rift blocks and overprinting volcanoes. The link to the Julia Lineament was not adequately tested due to sparse coverage. Closer to the Loyalty Ridge, a thick, faulted sedimentary basin was found. POSTER INITIAL WAVEHEIGHT OF LANDSLIDE TRIGGERED TSUNAMIS: APPLICATION OF A SIMPLISTIC EMPIRICAL APPROACH P. Barnes & A. Pallentin National Institute of Water & Atmospheric Research, Private Bag 14901, Wellington. (a.pallentin*niwa.co.nz) The seafloor associated with New Zealand’s active margin is locally susceptible to slope failure. In areas of frequent large earthquakes, steep slopes, and high sediment load, submarine landslides are extremely common. Large failures, particularly in 50 th Kaikoura05 -3- Kaikoura 2005
Page 1: CHARACTERISATION OF NEW ZEALAND NEP
Page 5 and 6: ange of lower resolution or fragmen
Page 7 and 8: CRETACEOUS-EOCENE TRANSGRESSION MAR
Page 9 and 10: consists of a well-developed canyon
Page 11 and 12: model. The relative position of the
Page 13 and 14: converts to plate theory. Thus, the
Page 15 and 16: and on the following morning the mi
Page 17 and 18: the LGM grass peak. This period of
Page 19 and 20: offshore west coast to offshore eas
Page 21 and 22: 4 Institut de Recherche pour le Dé
Page 23 and 24: VEGETATION AND CLIMATE CHANGE AT TH
Page 25 and 26: wider range. The youngest layer has
Page 27 and 28: few normal faults visible especiall
Page 29 and 30: TRACKING CRUSTAL DIFFERENTIATION AN
Page 31 and 32: EMPIRICAL SCALING RELATIONS FOR SEI
Page 33 and 34: hydrovolcanic eruptions then took p
Page 35 and 36: and that the MTL marks a Late Carbo
Page 37 and 38: faunal changes within these cores w
Page 39 and 40: material at subsurface depths of se
Page 41 and 42: survived through in low numbers in
Page 43 and 44: in the TVZ and southern Havre Troug
Page 45 and 46: Tephra beds are commonly used to ai
Page 47 and 48: The MCC is bounded by deep-seated t
Page 49 and 50: distal alluvial plains where large
Page 51 and 52: Many of the molluscs in the highly
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incremental slip history and paleoe
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This paper explores what we know of
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volcanism and a linear vent oriente
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These areas are also described in
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3D IMAGING OF THE FORE- AND BACKTHR
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ascending methane fluids/gases of p
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THE GRIFFENS ROAD TEPHRAS: VALUABLE
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sideritic concretions that occur in
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with 63.8%, and then [3] with 49.9%
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U-Th-Ra disequilibria data. In part
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landslide tsunami in the past. Rece
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core complex mode, temperature driv
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truncating three plutonic suites of
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active, andesitic White Island volc
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and voluminous than at any on Earth
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oundaries and with immature source
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The new era of commercial viability
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TECTONICS OF THE GALATEA BASIN USIN
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performed by the electron backscatt
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25km northeast of the volcano. Alth
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Most of the tectonic blocks in the
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TECTONIC AND NON-TECTONIC CAUSES OF
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The continental shelf of the Povert
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5 Dept. of Mineral Sciences, Smiths
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Adams CJ...........................
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Naish T............................
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