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

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Pleistocene-Holocene. The 22-17 ka terrace records on its carved surface the inversion of flow direction (from east- to west-directed) of an early paleodrainage, forced by backtilting of the hanging wall. The Ostler fault consists of sub-parallel, splaying segments within a deformation zone up to 2 km wide. Faults are marked by fresh scarps (�20 m high), which truncate suspended drainage systems. N-S anticlinal deformation of the hanging wall is traced by deformation of the 125 and 22-17 ka terraces, with the fold crest truncated by systems of N-S, W-dipping normal faults. A preliminary interpretation that incorporates the surface geology and the available geophysical information is that the Ostler fault is a footwall shortcut to an inverted normal fault that bounds the eastern margin of a Mesozoic (?) - Tertiary basin hidden below the thick Plio-Pleistocene cover. Compressional inversion of the early normal fault and shortening of the basin infilling since Miocene times has resulted in the progressive elevation of the fault hanging wall during deposition of the Plio- Pleistocene terrestrial sequence, and in the propagation of a number of reverse fault splays that cut the continental sequence at surface. This interpretation will be tested by the planned seismic profiles, adding to our understanding of compressional deformation off the Alpine Fault. ORAL EARLY CRETACEOUS UPPER CRUSTAL MAGMATISM IN SOUTHWEST FIORDLAND: GEOCHRONOLOGICAL AND GEOCHEMICAL HIGHLIGHTS M.R.Gollan 1 ,J.M.Palin 1 ,K.Faure 2 ,&C.Harris 3 1 Department of Geology, University of Otago, P.O.Box 56, Dunedin, New Zealand 2 Institute of Geological and Nuclear Sciences, P.O.Box 31 312, Lower Hutt 3 Geological Sciences, University of Cape Town, Rondebosch 7700, South Africa (malcolmgollan*ihug.co.nz) Southwest Fiordland contains an important record of Early Cretaceous plutonism, which is not complicated by a polyphase metamorphic overprint as in central and northern Fiordland. Recent mapping as part of the IGNS Qmap Fiordland programme (work in progress) has identified multiple Paleozoic through Mesozoic plutons composing the previously undivided Kakapo Granite of Wood (1960) in southwest Fiordland (Turnbull, pers. com.). Field, petrographic, geochemical, and geochronologic data reveal a transition from early Cretaceous LoSY to HiSY magmatism (cf. Tulloch & Kimbrough 2003) in the area around Preservation Inlet. The Revolver Pluton (Rp) of c.200 km 2 is the largest unit. It is a LoSY, coarse grained biotite granite with distinctive pink alkali feldspar megacrysts. LA-ICP-MS zircon U-Pb dating of Rp from Revolver Bay yields an age of 132.4 ± 1.0 Ma, in agreement with an unpublished TIMS zircon age of Tulloch (reported in Mortimer at al., 1999). Granodiorite from the northeast sector of Rp, here named the Long Scarp Granodiorite (Lsg), gives a coeval age of 132.0 ± 0.9 Ma and may represent a marginal facies of Rp. Treble Mountain Granite (Tmg, Turnbull, pers. com.) is a medium to coarse grained biotite granite that intrudes Rp on the west side of Isthmus Sound, and yields an age of 130.4 ± 0.9 Ma. Tmg locally exhibits severe hydrothermal alteration and hosts epithermal base-metal vein mineralisation which was worked in the historic Tarawera Mine. Trevaccoon Diorite (Tdi, Turnbull, pers. com.) is a hornblende gabbro that outcrops along the western shore of Long Sound north of Lady Bay and has an age of 128.7 ± 1.0 Ma. A younger granite, here named Upper Blacklock Granite (Ubg), occurs between Rp and Lsg. Ubg is petrographically similar to Rp, but can be distinguished on the basis of its geochemistry and age of 124.7 ± 1.0 Ma. Hornblende-rich HiSY diorite to gabbro, here named Only Island Diorite (Oid), outcrops south from Only Island where it intrudes Ubg. The composition and age of 122.1 ± 0.9 Ma of Oid suggest it is a higher level, unmetamorphosed equivalent of the Western Fiordland Orthogneiss. The presence of 15% inherited 149-136 Ma zircons in all units except Oid suggests a shared deeper source region comparable in age to Median Suite rocks dated by Muir et al. (1998) in eastern Fiordland. Oxygen isotope values (whole rock � 18 O = 6-9, quartz � 18 O = 8-10) for all units other than Tmg are consistent with such a source and, together with the rarity of older inherited zircons, limit contamination by the surrounding Ordovician metasediments (� 18 O whole rock = 12-18). Tmg quartz and feldspar � 18 O are strongly depleted indicating that hydrothermal alteration was caused by circulation of meteoric water. This supports the interpretation that plutons in the region were intruded at shallow crustal levels (
EMPIRICAL SCALING RELATIONS FOR SEISMIC FAULTS Álvaro González 1 , Javier B. Gómez 1 & Amalio F. Pacheco 2 1 Dept. de Ciencias de la Tierra. Universidad de Zaragoza. 50009 Zaragoza (Spain). 2 Dept. de Física Teórica y BIFI. Universidad de Zaragoza. 50009 Zaragoza (Spain). (Alvaro.Gonzalez*unizar.es) We are trying to clarify the scaling relations between several parameters of seismic faults: the fault length (L), slip rate (S), recurrence interval of large earthquakes (T) and coseismic displacement (D). To do this, we have compiled a data set of about 600 ground-breaking faults (extensional, compressional and strike-slip) from all continents. For each fault, the parameters included in the database have not been estimated one from another. We have tested four relations proposed previously, and found a new one: 1. Wallace (1970) suggested that T = D / (S – C), where C is the creep rate. This parameter is frequently zero, and is rarely known. Excluding it, the relation becomes T �D/S, and holds for most faults for which T, D, and S were available in our database. 2. The previous formulae suggest that T is proportional to S -1 . This was previously verified for a smaller data set by Villamor and Berryman (1999), and also holds in ours. 3. As previously found in smaller data sets (Bilham and Bodin, 1992; Nicol et al., 1997; Wesnousky, 1999; Nicol et al., 2005), longer faults tend to have faster slip rates. In our composite data set, S is roughly proportional to L 2 4. . From relations [2] and [3], T should be roughly proportional to L -2 , and our data show that this is the case. This is important to seismic hazard assessment: it implies that 5. earthquakes on large faults can not only be larger, but also more frequent, than those of short faults. Turcotte (1992) also proposed that T was proportional to a negative power of L, although Marrett (1994) pointed out that this power could be positive for large faults, and Nicol et al. (2005) assumed that T and L do not correlate to each other, at least in extensional faults. Finally, a new scaling relation has been found for the whole data set: S is proportional to the ratio L/T. Interestingly, this relation (as [1]) is dimensionally homogeneous (both its sides are measured in the same units), and less scattered than relations [2] and [4], where T is also involved. Because L and S are among the easiest parameters to determine, this relation could be useful as a first-order approximation of T. In case D is also known, T can be better estimatedbyusingrelation[1]. Bilham, R. and Bodin, P. (1992) Science 258, 281-284. | Marrett, R. (1994) Geophys. Res. Lett. 21, 2637-2640. | Nicol, A. et al. (1997) Nature 390, 157-159. Nicol, A. et al. (2005) J. Struct. Geol. 27, 541-551. Turcotte, D. L. (1992) Fractals and Chaos in Geology and Geophysics. Cambridge Univ. Press. Villamor, P. and Berryman, K. R. (1999) Primer congreso nacional de ingeniería sísmica, Murcia (Spain), vol. 1, 153-163. Wallace, R. E. (1970) Geol. Soc. Am. Bull. 81, 2875- 2890. Wesnousky, S. G. (1999) Bull. Seismol. Soc. Am. 89, 1131-1137. ORAL PETROLOGY OF NEWLY DISCOVERED SUBMARINE VOLCANIC ROCKS FROM THE TONGA-KERMADEC ARC: INITIAL RESULTS Ian J. Graham 1 ,IanE.M.Smith 2 , Richard J. Arculus 3 Susan McDonnell 4 Cornel E.J. de Ronde 1 &IanC.Wright 5 1 Institute of Geological & Nuclear Sciences Ltd, PO Box 31-312, Lower Hutt, New Zealand 2 Auckland University, Private Bag 92019, Auckland, New Zealand 3 Australian National University, Canberra, ACT 2601, Australia 4 Department of Geology, Donovans Road, UCC, Cork, Republic of Ireland 5 National Institute of Water & Atmospheric Research, PO Box 14901, Wellington, New Zealand (i.graham*gns.cri.nz) The NZAPLUME III research cruise to the northern Kermadec – southern Tonga arc during September- October 2004 mapped and dredge-sampled eight newly discovered volcanic centres along the arcfront, including Monowai, now known to have a caldera complex immediately to the north of the previously mapped cone. These centres, which typically include one or more calderas with multiple associated volcanic cones, have an average spacing of 47 km, slightly greater than the average spacing of 41 km for the entire Kermadec arc (i.e., from Whakatane in the south to Monowai to the north). All of the newly discovered volcanic centres show evidence of hydrothermal venting and, in the case of Monowai, recent eruptive activity. The dredged lavas have calc-alkaline compositions ranging from high-alumina basalt to rhyolite, confirming the occurrence of evolved lava 50 th Kaikoura05 -31- 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 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: TRACKING CRUSTAL DIFFERENTIATION AN
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
Page 73 and 74: landslide tsunami in the past. Rece
Page 75 and 76: core complex mode, temperature driv
Page 77 and 78: truncating three plutonic suites of
Page 79 and 80: active, andesitic White Island volc
Page 81 and 82:
and voluminous than at any on Earth
Page 83 and 84:
oundaries and with immature source
Page 85 and 86:
The new era of commercial viability
Page 87 and 88:
TECTONICS OF THE GALATEA BASIN USIN
Page 89 and 90:
performed by the electron backscatt
Page 91 and 92:
25km northeast of the volcano. Alth
Page 93 and 94:
Most of the tectonic blocks in the
Page 95 and 96:
TECTONIC AND NON-TECTONIC CAUSES OF
Page 97 and 98:
The continental shelf of the Povert
Page 99 and 100:
5 Dept. of Mineral Sciences, Smiths
Page 101 and 102:
Adams CJ...........................
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Naish T............................
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