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

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Inferred U. Cretaceous eustatic unconformities (shaded) and sequence boundaries, and significant event-clusters in the East Coast Basin: filled triangles = clusters that coincide with New Jersey unconformities; open triangles = clusters that do not. ORAL WHERE IS THE CENOMANIAN-TURONIAN BOUNDARY IN NEW ZEALAND, AND IS THERE A HYDROCARBON SOURCE ROCK ASSOCIATED WITH IT? J. Crampton 1 ,B.Field 1 & T. Hasegawa 2 1 GNS Science, Box 30368, Lower Hutt, New Zealand 2 Department of Earth Sciences, Faculty of Science, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan (j.crampton*gns.cri.nz) An oceanic anoxic event around the time of the Cenomanian-Turonian boundary (CTB) in many parts of the world resulted in widespread occurrence of black shales and a hydrocarbon source rock interval. Did a similar event occur in New Zealand? Hydrocarbon generation modelling (Field & Uruski et al. 1997) suggests there was generation of hydrocarbons from mid-Cretaceous rocks on the East Coast North Island, but we do not know specifically what the sources for these hydrocarbons were. Crampton et al. (2001) placed the CTB within the Arowhanan Stage at Mangaotane Stream, Raukumara Peninsula. The Mangaotane section of grey, red and green mudstones, with minor sandstones, was re-collected in detail for the present study and samples were analysed for carbon isotopes and total organic carbon (TOC). A carbon isotope signature consistent with that at the CTB in other parts of the world was found within the Arowhanan, but RockEval results indicate that the event at Mangaotane Stream did not produce high enough TOCs to form a good source rock. We cannot rule out the possibility that there are CTB black shales elsewhere on the East Coast or in the New Zealand region. The absence at Mangaotane Stream might be due to factors in its local setting such as rate of terrigenous input, paleobathymetry or oceanic paleocurrents. Our results confirm the correlation of the Arowhanan with the CTB (Cooper 2004), provide a SW Pacific datapoint for modellers of Cretaceous paleoclimates, and indicates that the CTB event in New Zealand was, at least in detail, different to that at classic Northern Hemisphere sections. Crampton, J.S., Raine, I., Strong, P., Wilson, G. 2001: Integrated biostratigraphy of the Raukumara Series (Cenomanian-Coniacian) at Mangaotane Stream, Raukumara Peninsula, New Zealand. New Zealand Journal of Geology and Geophysics 44: 365-389. Cooper, R.A. (ed.), 2004: The New Zealand Geological Timescale. Institute of Geological and Nuclear Sciences Monograph 22, 284pp. Field, B.D., Uruski, C.I., and others, 1997: Cretaceous- Cenozoic geology and petroleum systems of the East Coast Region, New Zealand. Institute of Geological and Nuclear Sciences Monograph 19. 301pp. POSTER CHRONIC HEALTH IMPACT OF FLUORIDE DUE TO VOLCANIC DEGASSING ON AMBRYM, VANUATU R. Crimp 1 ,S.Cronin 1 ,D.Charley 2 , C. Oppenheimer 3 &P.Bani 4 1 Institute of Natural Resources, Massey University, Palmerston North, New Zealand 2 Department of Geology, Mines & Water Resources, Port Vila, Vanuatu. 3 Department of Geography, University of Cambridge, Cambridge, United Kingdom 50 th Kaikoura05 -20- Kaikoura 2005
4 Institut de Recherche pour le Développement, Noumea, New Caledonia (r.j.crimp*massey.ac.nz) Fluoride is a common constituent of volcanic ash and has been implicated in human and animal morbidity and mortality, for example the Laki Fissure eruptions in Iceland (1783-1784, 1947, and 1970). The 1995-1996 Ruapehu eruptions also resulted in thousands of sheep deaths which similarly were attributed to acute fluoride poisoning. The island volcano Ambrym has several open vents, including Marum and Benbow, within a centrally-located caldera. These have been semicontinuously active for at least two to three hundred years. The predominant southeast trade winds direct volcanic plumes toward the west where the majority of the population of over 9000 resides. Wind variability, particularly during the cyclone season, ensures that no area of Ambrym is entirely immune from volcanic emissions. In January 2005, the Ambrym plume was emitting SO2 at 14 000 - 20 000 tonnes/day, with a fluoride output estimated to be up to 1 100 tonnes/day. The continuous degassing from Ambrym’s vents leads to acid rain and ash fall causing damage to food crops and vegetation. In terms of acute human health impacts, respiratory and gastric symptoms are commonly reported following particularly intense periods of activity. This study focuses on the chronic human health impacts that prolonged exposure to volcanogenic fluoride may have on the local population. The plume fluoride appears to be very efficiently scavenged by rainfall, which the island residents collect for drinking and cooking purposes. Drinking water samples collected in January 2005 typically contained between 3-10 ppm F, with streams, shallow ground wells and coconuts having similarly high F contents. To put this in perspective, the World Health Organisation recommends < 1.0 ppm F in the drinking water of populations living in tropical environments. In humans, ingested fluoride is deposited primarily in bones and teeth. Dental fluorosis – evidenced by white or brown discolouration of teeth - is the first visible sign of over-exposure to fluoride and occurs where levels of fluoride in drinking water are 1-2 ppm. The Dean’s Index is a visual scale for the classification of fluorosis and was used to assess over 250 children in West Ambrym. Of these children, 53% and 8% respectively, fell into the two highest categories of Moderate and Severe. The dental results and water analyses suggest that skeletal fluorosis, a condition involving weakening of bones, which in its severest form is crippling, is a potential health issue. As fluorosis has been linked with Ruapehu’s eruptions, this study is of significance for researchers investigating the risks associated with possible prolonged degassing of any of New Zealand’s Central North Island volcanoes. ORAL WHERE ARE THE GIANT TUFF CONE AND IGNIMBRITES OF AMBRYM? A MORE CONVENTIONAL STORY OF MAFIC VOLCANISM AT AMRBYM VOLCANO, VANUATU. Shane J. Cronin & Károly Németh Massey University, Institute of Natural Resources, PO Box 11 222, Palmerston North, NZ (S.J.Cronin*massey.ac.nz) Ambrym is located in the central part of the Vanuatu volcanic arc and forms a triangular shaped island around 60 km long on its NE-SW axis. The NW-SE oriented rift zone accommodates most of the historic eruptions from this arc-basaltic volcano and a series of older overlapping edifices make up the northern portion. A 12 km-wide caldera dominates the centre of the island, containing two active tuff/scoria cones (Benbow, Marum) and many smaller open vents. Semi-continuous ash falls and periodic lava flows inundate the caldera and choke stream networks down-slope with remobilised pyroclastics. Since the mid 90’s Ambrym has been regarded as a type-locality for a “giant tuff cone”, that formed by enormous phreatomagmatic eruptions, which accompanied disruption of an edifice to form the large caldera. This theory, however, is entirely built on field observations of a layer-cake stratigraphy constructed from a mosaic of sections. Current field studies revisiting these sites and others, show that this mosaic is false, and many of the sections cannot possibly be related to one another either genetically or chronologically. Our studies indicate that the island is a composite structure, formed of many generations of coalescing monogenetic volcanic fields. The type localities of the “giant tuff cone” (dacitic) pycroclastic flow deposits in the northern shoreline of the island we interpret to be either (1) mafic phreatomagmatic fall and surge sequences (in places hydrothermally altered) or in other cases (2) stacks of lahar and fluvial sediment derived from the caldera outflow and forming valley-fills. These successions are typical of many new sites described around the volcano which imply several generations of a frequently active mafic volcano, with coalescing fields of lava, basesurge deposits and falls (often with accretionary lapilli), along with abundant deposits of fluvially reworked pyroclastics. There is no evidence for a climactic (or for that matter dacitic) explosive caldera-forming event, which concurs with 50 th Kaikoura05 -21- Kaikoura 2005
Page 1 and 2: CHARACTERISATION OF NEW ZEALAND NEP
Page 3 and 4: myrtaceous. One 20 mm diameter flow
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: offshore west coast to offshore eas
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
Page 53 and 54: incremental slip history and paleoe
Page 55 and 56: This paper explores what we know of
Page 57 and 58: volcanism and a linear vent oriente
Page 59 and 60: These areas are also described in
Page 61 and 62: 3D IMAGING OF THE FORE- AND BACKTHR
Page 63 and 64: ascending methane fluids/gases of p
Page 65 and 66: THE GRIFFENS ROAD TEPHRAS: VALUABLE
Page 67 and 68: sideritic concretions that occur in
Page 69 and 70: with 63.8%, and then [3] with 49.9%
Page 71 and 72:
U-Th-Ra disequilibria data. In part
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landslide tsunami in the past. Rece
Page 75 and 76:
core complex mode, temperature driv
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truncating three plutonic suites of
Page 79 and 80:
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
Page 99 and 100:
5 Dept. of Mineral Sciences, Smiths
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Adams CJ...........................
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Naish T............................
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