DOCSLIB.ORG

Seismic Stratigraphy and Structurel History of the Reinga Basin and Its

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Seismic Stratigraphy and Structurel History of the Reinga Basin and Its 9 ‘ of 1997, 40: New Zealarid JOUI-F~UIGeolog?) arid Geoplivsìcs, 1/01. 425-45 1 425 0028-8306/97/4004-0425 $7.00/0 0 The Royal Society of New Zealand 1997 Seismic stratigraphy and structural history of the Reinga Basin and its margins, southern Norfolk Ridge system 4 I ,I Oligocene condensed sequence, separates the Paleogene and 6 R. H. HERZER’ G. C. H. CHAPRONIERE2 Neogene sequences. The Neogene sequences record sedimentary infill from A. R. EDWARDS3 several source directions, not only from the New Zealand landmass, but from the north and west as well. Near the Northland coast, sediment accumulated in clastic wedges and ponded sub-basins from the Miocene to the present day. Along the flanking ridges to the northwest, similar deposition G. H. SCOTTI occurred in the Early and Middle Miocene but changed in v. STAGPOOLE’ the Late Miocene to sedimentation in drifts flanked by c. P. STRONG’ scours. This change reflects the end of tectonism, a diminishing clastic sediment supply, and the establishment P. SYMONDS~ J. of a throughgoing oceanic current regime as the marginal G. WILSON’ ridges submerged. This pattern of sedimentation persists H. ZHU’ today. ‘Institute of Geological & Nuclear Sciences Post-Cretaceous volcanism occurred in two parts of the P.O. Box 30 368 basin. In the central southeastern part, volcanic bodies in Lower Hutt, New Zealand the ?Oligocene to Early Miocene sequences could be a northwestern extension of the Northland volcanic arc. In the 2Australian Geological Survey Organisation western part, small intrusive and extrusive bodies appear to P.O. Box 378 be of Pliocene intraplate origin. Canberra ACT 260 1, Australia Compression (or transpression) had an important role in developing the basin’s present form. Miocene compressional 3Stratigraphic Solutions structures-asymmetric anticlines, reverse faults, everted P.O. Box 295 basins, and pop-ups-are present everywhere but at the Waikanae, New Zealand southeastern end. The present marginal ridges have structurally complex origins. The Reinga Ridge which forms 41nsitut Français de Recherche Scientifique pour the northeastern margin is a transform boundary with the le Développement en Coopération Norfolk backarc basin. Deformation thought to be caused ORSTOM by the action of the transform is recorded in folded and B.P. A5 faulted Cretaceous-Paleogene sequences and syntectonic Nouméa, New Caledonia Early and Middle Miocene sequences along its length. The southwestern margin of the basin is a double ridge comprising the Wanganella Ridge, an early Middle to early Abstract The Reinga Basin northwest of the North Island Late Miocene, compressional uplift, and the older, eroded of New Zealand was initially formed by crustal extension West Norfolk Ridge, which contains Cretaceous half- in Cretaceous time. Gravity models suggest up to 3540% grabens. The northern half of the Wanganella Ridge is an crustal thinning. The seismic stratigraphy of the basin is everted ?Oligocene to Early Miocene aulacogen in which continuous with that of the offshore western North Island, slivers of basement rock were thrust up along with the where reflectors are well constrained by oil exploration data. sedimentary fill, whereas the southern half is an uplifted In the Reinga Basin, there are two Cretaceous sequences block of folded sedimentary rocks of probable Cretaceous above an older Mesozoic basement. The lower sequence is or older age. apparently terrestrial and may include both pre-rift and syn- Paleogeographic reconstructions show that Oligocene rift subsequences; the upper is a rift-filling marine sequence. uplift of the Norfolk Ridge and Miocene uplift of the Reinga These are overlain by Paleocene and Eocene blanket Ridge could have provided a means for terrestrial biota of sequences that .were laid down during a period of relative New Caledonian affinities to spread into New Zealand. tectonic quiescence consistent with cooling subsidence, The total sediment thickness in the Reinga Basin is continued submergence, a northeast-facing continental shelf, estimated to be 3.5-5.5 km. Potential source, seal and and absence of a significant active plate boundary. A strong reservoir rocks are present, and there is an abundance of regional reflector, caused by a combined unconformity and suitable structures. The potential for petroleum occurrences in the basin is good. Keywords seismic stratigraphy; gravity; tectonism; land P. .... G97011 bridges; petroleum potential; New Zealand; Reinga Basin; Received 13 Februayv 1997: accepted 14 August I997 Norfolk Ridge -- Fonds Documentaire O I?S”TOPlii i 426 New Zealand Journal of Geology and Geophysics, 1997, Vol. 40 Fig. 1 Location and morphostructural elements of the Reinga Basin. Heavy lines = generalised major Neogene fault systems. Light stipple = known limit of Northland Allochthon. Dark shaded circles = ?Oligocene-Miocene volcanoes. Those near Northland were identified in previous studies (herzer 1995); the group in the centre of the basin were identified in this study. Volcanoes of the Three Kings Ridge arc are not shown. Hatching = area of occluded zone. Medium shading = area of folded zone. NR = Norfolk Ridge. PS = Petrel Spur. VMFZ = Vening Meinesz Fracture Zone. + = interpreted Pliocene igneous bodies. @ = dredge locations. Because of space, the labels of dredge stations of cruise RE9302 are shortened here to RE. In the text and Table 1 they are given in full. Regional seismic profiles of Fig. 5-9 are shown (see Fig. 2 for labels). INTRODUCTION Norfolk Ridge (Shor et al. 1971), and c. 25 km beneath the Northland peninsula (Stem et al. 1987). Marine gravity The Reinga Basin is a long, sediment-filled trough extending studies reveal similar crustal thicknesses under the other c. 500 km northwest of the North Island of New Zealand. major ridges and reduced thicknesses of 15-20 km under The basin is bounded to the northeast by the Reinga Ridge the basins (Uruski & Wood 1991; Wood 1991; Zhu & and the Northland peninsula, and to the southwest by a pair Symonds 1994). Evidence for Cretaceous ductile deform- of parallel ridges-the Wanganella Ridge and West Norfolk ation due to northeast extension is found in core complexes Ridge (WNR) (Fig. 1). It is almost closed at its northwestem in the western and northern South Island dated as 114 k end where the Reinga, Norfolk, and Wanganella Ridges meet 18 Ma and 109.6 5 1.7 Ma (Tulloch & Kimbrough 1989; but opens southeastwards into the New Caledonia Basin. Muir et al. 1994). Granite-derived, mainly terrestrial deposits The Pacific side of the Reinga Ridge is the present of similar age fill rifts in the westem South and North Islands U continental margin, formed by the Vening Meinesz Fracture (Laird 1993; Shell, BP & Todd 1986). Zone (VMFZ), a transform fault that separates the Reinga Tectonic deformation of the Reinga Basin was noted by Basin from the Norfolk back-arc basin and Three Kings Davey (1 977) and discussed by Eade (1988) who attributed remnant arc (Mascle et al. 1994; Herzer & Mascle 1996). compressional structures in the Reinga and New Caledonia The Reinga Basin has never been the object of a focused Basins and uplift of the West Norfolk and Wanganella Ridges study. Those basins west of New Zealand that have been to the Eocene compression that led finally to obduction of studied have been found to be rift basins (e.g., Bishop 1992; the New Caledonia ophiolite in the Early Oligocene, In Isaac et al. 1994; Kamp 1986; Nathan et al, 1986; Uruski & Eade's model the Wanganella Ridge is portrayed as a large Wood 1991 : Laird 1993; Wood 1994) formed during the New southwest-directed thrust. Although the case for Eocene Zealand-Australia breakup of Gondwana, and the opening compression in New Caledonia is well documented (e.g., of the Tasman Sea from mid-Cretaceous to Early Eocene Parrot & Dugas 1980; Regnier 1988; Aitchison et al. 1995), time (Shaw 1978; Veevers & Li 1991). Previous geophysical there is no evidence of contemporaneous compression in studies indicate that attenuated continental crust underlies nearby northern New Zealand (Isaac et al. 1994). the greater region. Long offset seismic refraction surveys Recent studies, based on new seismic reflection, swath record a depth to the mantle of c. 15 km under the New bathymetric, and geological data, demonstrate that some of Caledonia Basin, 20 km under the Lord Howe Rise and the deformation in the Reinga Basin coincided with the Herzer et al.-Reinga Basin and its margins 427 I Fig. 2 Total seismic reflection profile coverage. Thick lines = regional profiles shown as line drawings. Heavy dotted lines = locations of gravity profiles shown in Fig. 4. Boxes = locations of illustrated seismic profiles. opening of the Norfolk backarc basin in the Early Miocene coverage was almost doubled with 2000 km of single (Mascle et al. 1994; Herzer & Mascle 1996; Mortimer et al. channel, seismic reflection data by the Institute of Geological in press). The Reinga Ridge, which actually consists of a & Nuclear Sciences (IGNS) (RE lines, Cruise RE9302, RV chain of left-stepping, en echelon structural .blocks, Akademik M.A. Lavrentyev), 700 km of 96-channel data by developed during this time by transpressive deformation as the Australian Geological Survey Organisation (AGSO) the Three Kings Ridge migrated southeastward along the (Marshall et al. 1994) (RS lines, Cruise RS114, RV Rig Vening Meinesz transform. These events were heralded in Seismic), and 1200 km of 6-channel data by the French the latest Oligocene to earliest Miocene (Waitakian) by the Centre National de la Recherche Scientifique (CNRS) - obduction of the Northland Allochthon (Ballance & Spörli (Mascle et al. 1994) and AGSO, respectively (TN and TS 1979) onto the continental margin occupied by the present- lines, Cruises TRANSNOR and TASMANTE, RV day southeastern Reinga Ridge and Northland peninsula. I 'Atalante). The resulting grid comprises 14 transverse lines Arc volcanism was active in the Early Miocene on and and adequate longitudinal lines to tie them (Fig.
Load more

Recommended publications
  • Vulnerable Marine Ecosystems – Processes and Practices in the High Seas Vulnerable Marine Ecosystems Processes and Practices in the High Seas
    ISSN 2070-7010 FAO 595 FISHERIES AND AQUACULTURE TECHNICAL PAPER 595 Vulnerable marine ecosystems – Processes and practices in the high seas Vulnerable marine ecosystems Processes and practices in the high seas This publication, Vulnerable Marine Ecosystems: processes and practices in the high seas, provides regional fisheries management bodies, States, and other interested parties with a summary of existing regional measures to protect vulnerable marine ecosystems from significant adverse impacts caused by deep-sea fisheries using bottom contact gears in the high seas. This publication compiles and summarizes information on the processes and practices of the regional fishery management bodies, with mandates to manage deep-sea fisheries in the high seas, to protect vulnerable marine ecosystems. ISBN 978-92-5-109340-5 ISSN 2070-7010 FAO 9 789251 093405 I5952E/2/03.17 Cover photo credits: Photo descriptions clockwise from top-left: Acanthagorgia spp., Paragorgia arborea, Vase sponges (images courtesy of Fisheries and Oceans, Canada); and Callogorgia spp. (image courtesy of Kirsty Kemp, the Zoological Society of London). FAO FISHERIES AND Vulnerable marine ecosystems AQUACULTURE TECHNICAL Processes and practices in the high seas PAPER 595 Edited by Anthony Thompson FAO Consultant Rome, Italy Jessica Sanders Fisheries Officer FAO Fisheries and Aquaculture Department Rome, Italy Merete Tandstad Fisheries Resources Officer FAO Fisheries and Aquaculture Department Rome, Italy Fabio Carocci Fishery Information Assistant FAO Fisheries and Aquaculture Department Rome, Italy and Jessica Fuller FAO Consultant Rome, Italy FOOD AND AGRICULTURE ORGANIZATION OF THE UNITED NATIONS Rome, 2016 The designations employed and the presentation of material in this information product do not imply the expression of any opinion whatsoever on the part of the Food and Agriculture Organization of the United Nations (FAO) concerning the legal or development status of any country, territory, city or area or of its authorities, or concerning the delimitation of its frontiers or boundaries.
    [Show full text]
  • Proposal to Study Subduction Initiation in Northern Zealandia Tim Stern1
    Proposal to study subduction initiation in northern Zealandia Tim Stern1, Rupert Sutherland2 1 Victoria University of Wellington; 2 GNS Science, Lower Hutt [email protected] Back-arc regions of subduction zones contain sedimentary records that hold clues to the subduction initiation process, and provide complementary insights to fore-arc studies (e.g. Izu-Bonin-Mariana and Tonga). The basins and sedimentary platforms northwest of New Zealand record onset of the Tonga –Kermadec (TK) system during the Eocene- Oligocene (see Gurnis et al. white paper). We propose (mainly) marine geophysical studies that will reveal clues as to how and why TK, and Hikurangi, subduction started. Key features that require study are: Norfolk Ridge (NR); New Caledonia Trough (NCT); Taranaki-Wanganui basins; and Three Kings Ridge (TKR). The NR is where surface convergence was associated with initial subduction. What was the vergence and timing of thrusting, what vertical motions took place, and how do these observations compare and discriminate alternate geodynamic model predictions? The New Caledonia Trough lies adjacent to Norfolk Ridge, was deformed in the subduction initiation event and subsided with large magnitude (Sutherland and al., 2010) that is precisely quantified (1.5 km) at its southern end near the north end of Taranaki Basin (Baur et al., 2013). What was the regional timing of NCT subsidence in relation to other aspects of subduction initiation, and what is its significance? Does the 1.5 km of Oligocene “platform subsidence” seen in oil company drill hole data from South Taranaki Basin at ~ 30 Ma (Stern and Holt, 1994) have a common cause as that in the NCT ? If so, the process occurs on a ~1000 km scale and is clearly geodynamically significant.
    [Show full text]
  • 32-1 Arculus.Pdf
    OceTHE OFFICIALa MAGAZINEn ogOF THE OCEANOGRAPHYra SOCIETYphy CITATION Arculus, R.J., M. Gurnis, O. Ishizuka, M.K. Reagan, J.A. Pearce, and R. Sutherland. 2019. How to cre- ate new subduction zones: A global perspective. Oceanography 32(1):160–174, https://doi.org/ 10.5670/oceanog.2019.140. DOI https://doi.org/10.5670/oceanog.2019.140 PERMISSIONS Oceanography (ISSN 1042-8275) is published by The Oceanography Society, 1 Research Court, Suite 450, Rockville, MD 20850 USA. ©2019 The Oceanography Society, Inc. Permission is granted for individuals to read, download, copy, distribute, print, search, and link to the full texts of Oceanography articles. Figures, tables, and short quotes from the magazine may be republished in scientific books and journals, on websites, and in PhD dissertations at no charge, but the materi- als must be cited appropriately (e.g., authors, Oceanography, volume number, issue number, page number[s], figure number[s], and DOI for the article). Republication, systemic reproduction, or collective redistribution of any material in Oceanography is permitted only with the approval of The Oceanography Society. Please contact Jennifer Ramarui at [email protected]. Permission is granted to authors to post their final pdfs, provided byOceanography , on their personal or institutional websites, to deposit those files in their institutional archives, and to share the pdfs on open-access research sharing sites such as ResearchGate and Academia.edu. DOWNLOADED FROM HTTPS://TOS.ORG/OCEANOGRAPHY SPECIAL ISSUE ON SCIENTIFIC OCEAN DRILLING: LOOKING TO THE FUTURE HOW TO CREATE NEW SUBDUCTION ZONES A Global Perspective By Richard J. Arculus, Michael Gurnis, Osamu Ishizuka, Mark K.
    [Show full text]
  • Avian Evolution, Gondwana Biogeography and the Cretaceous
    doi 10.1098/rspb.2000.1368 Avian evolution, Gondwana biogeography and the Cretaceous±Tertiary mass extinction event Joel Cracraft Department of Ornithology, American Museum of Natural History, Central Park West at 79th Street, NewYork, NY 10024, USA ( [email protected]) The fossil record has been used to support the origin and radiation of modern birds (Neornithes) in Laurasia after the Cretaceous^Tertiary mass extinction event, whereas molecular clocks have suggested a Cretaceous origin for most avian orders.These alternative views of neornithine evolution are examined using an independent set of evidence, namely phylogenetic relationships and historical biogeography. Phylogenetic relationships of basal lineages of neornithines, including ratite birds and their allies (Palaeognathae), galliforms and anseriforms (Galloanserae), as well as lineages of the more advanced Neoaves (Gruiformes, Caprimulgiformes, Passeriformes and others) demonstrate pervasive trans- Antarctic distribution patterns.The temporal history of the neornithines can be inferred from fossil taxa and the ages of vicariance events, and along with their biogeographical patterns, leads to the conclusion that neornithines arose in Gondwana prior to the Cretaceous^Tertiary extinction event. Keywords: Neornithes; avian evolution; biogeography; Gondwana; Cretaceous^Tertiary extinction marker of neornithine beginnings.The fact that the 1. INTRODUCTION preponderance of the fossils are found in North America The relationships of modern birds, or Neornithes, to non- and Europe is taken as evidence that most higher taxa of avian theropods and Mesozoic pre-neornithine avian birds diversi¢ed on the Laurasian landmass and had lineages, is now well established (Chiappe 1995; Padian little, if anything, to do with Gondwana (Feduccia 1995). & Chiappe 1998; Chiappe et al.
    [Show full text]
  • Morphology and History of the Kermadec Trench–Arc–Backarc
    Marine Geology 159Ž. 1999 35±62 www.elsevier.nlrlocatermargeo Morphology and history of the Kermadec trench±arc±backarc basin±remnant arc system at 30 to 328S: geophysical profile, microfossil and K±Ar data Peter F. Ballance a,), Albert G. Ablaev b, Igor K. Pushchin b, Sergei P. Pletnev b, Maria G. Birylina b, Tetsumaru Itaya c, Harry A. Follas a,1, Graham W. Gibson a,2 a UniÕersity of Auckland, PriÕate Bag 92019, Auckland, New Zealand b Pacific Oceanological Institute, 43 Baltiyskaya Street, VladiÕostok 690041, Russian Federation c Research Institute of Natural Sciences, Okayama UniÕersity of Science, 1-1 Ridai-cho, Okayama 700, Japan Received 8 January 1998; accepted 27 November 1998 Abstract Knowledge of the time span of arc activity, essential for correct tectonic reconstructions, has been lacking for the Kermadec arc system, but is supplied in this paper through study of microfossils contained in dredge samples, and K±Ar ages on dredged basalt clasts. The Kermadec system at south latitudes 30 to 328 in the southwest Pacific comprises from west to east the Colville RidgeŽ. remnant arc , Havre Trough Ž backarc basin . , Kermadec Ridge Ž. active arc and Kermadec TrenchŽ site of west-dipping subduction of Pacific plate lithosphere beneath the Australian plate. Data are presented from two traversesŽ. dredge, magnetic, single-channel seismic across the whole system. An important transverse tectonic boundary, the 328S Boundary, lies between the two traverse lines and separates distinct northernŽ. 32±258S and southern Ž.32±368S sectors. The northern sector is shallower and well sedimented with broad ridges and a diffuse backarc basin.
    [Show full text]
  • Oceanography of the Coral and Tasman Seas*
    Oceanogr. Mar. Biol. Ann. Rev., 1967,5,49-97 Harold Barnes, Ed. Publ. George Auen and UnWin Ltd., London OCEANOGRAPHY OF THE CORAL AND TASMAN SEAS* H. ROTSCHI AND L. LEMASSON Ofice de la Recherche Scientijque et Technique Outre-Mer, Centre de Nouméa BATHYMETRY AND TOPOGRAPHY OF THE COR_-L AND TASMAN SEAS The Coral Sea extends between the Solomon Islands on the northeast, New Caledonia and the New Hebrides Islands on the east, and the coast of Queensland on the west while to the south it is limited by the Tasman Sea. To the northwest it communicates with the Arafura Sea by the shallow Torres Strait; at the Solomon Archipelago it opens on to the equatorial zone of the Pacifìc Ocean and comes under the influence of the central and tropical Pacific both in crossing the Archipelago of the New Hebrides and to the south of New Caledonia. The Coral Sea has a mean depth of the order of 2400 m with a maximum of 9140 m in the New Britain Trench. The Tasman Sea is limited to the north by the Coral Sea, to the east by New Zealand, to the west by the coast of New South Wales and to the south by Tasmania; in the south it is largely under the influence of the Antarctic Ocean and in the west under that of the central South Pacific. The maximum depth is 5943 m. BATHYMETRY As is apparent from the most recent bathymetric chart of these oceans (Menard, 1964) they have a complicated structure which is particularly evident in the Coral Sea.
    [Show full text]
  • “SEAMOUNT” Database: Recent Updates and Its Potential Use for Ecological Risk Assessment
    New Zealand Aquatic Environment and Biodiversity Report No. 27 2008 ISSN 1176-9440 New Zealand’s “SEAMOUNT” database: recent updates and its potential use for ecological risk assessment A. A. Rowden M. Oliver M. R. Clark K. Mackay New Zealand's "SEAMOUNT" database: recent updates and its potential use for ecological risk assessment A. A. Rowden M. Oliver M. R. Clark K. Mackay NIWA Private Bag 14901 Wellington 6241 New Zealand Aquatic Environment and Biodiversity Report No. 27 2008 Published by Ministry of Fisheries Wellington 2008 ISSN 1176-9440 © Ministry of Fisheries 2008 Citation: Rowden, A.A.; Oliver, M.; Clark, M.R.; Mackay, K. (2008). New Zealand's "SEAMOUNT" database: recent updates and its potential use for ecological risk assessment. New Zealand Aquatic Environment and Biodiversity Report No. 27. 49 p. This series continues the Marine Biodiversity Biosecurity Report series which ceased with No.7 in February 2005. EXECUTIVE SUMMARY Rowden, A.A.; Oliver, M.; Clark, M.R.; Mackay, K (2008). New Zealand's "SEAMOUNT" database: recent updates and its potential use for ecological risk assessment. New Zealand Aquatic Environment and Biodiversity Report No. 27. 49 p. I) NIWA's SEAMOUNT database was enhanced in order to improve its utility for fisheries managers addressing issues around the effects of bottom trawling on "seamounts". 2) Forty-one additional data fields were erected and populated to create a second version of the database (now with a total of 72 data fields). 3) Access to the updated database is restricted at present to NIW A and MFish. Broader public access is planned by 2010.
    [Show full text]
  • Eocene–Miocene Volcanoes Near Zealandia's Rifted Continental Margin
    1 Australian Journal of Earth Sciences Archimer 2021, Volume 68, Issue 3, Pages 368-380 https://doi.org/10.1080/08120099.2020.1805007 https://archimer.ifremer.fr https://archimer.ifremer.fr/doc/00646/75834/ The Norfolk Ridge seamounts: Eocene–Miocene volcanoes near Zealandia’s rifted continental margin Mortimer N. 1, * , Patriat Martin 2, Gans P. B. 3, Agranier Arnaud 4, Chazot Gilles 4, Collot Julien 5, Crundwell M. P. 6, Durance P. M. J. 6, Campbell H. J. 6, Etienne S. 5 1 GNS Science, Dunedin, New Zealand 2 IFREMER, Unité Géosciences Marines, Plouzané, France 3 Geological Sciences, University of California, Santa Barbara, USA 4 dLaboratoire Domaines Océaniques UMR/CNRS 6538, IUEM, Université de Bretagne Occidentale, Technopôle Brest-Iroise, Plouzané, France 5 Service Géologique de Nouvelle-Calédonie, Nouméa, New Caledonia 6 GNS Science, Lower Hutt, New Zealand * Corresponding author : N. Mortimer, email address : [email protected] Abstract : New age and geochemical data are used to investigate the origin of a ∼670 km-long line of eight seamount volcanoes along the western side of the Norfolk Ridge between New Caledonia and New Zealand. Altered lavas and limestones were dredged from three volcanoes during the 2015 Volcanic Evolution of South Pacific Arcs cruise of N/O l’Atalante, so a total of four, including the northernmost and southernmost, have now been directly sampled and analysed. Dating of lava and volcanic breccia clasts by Ar–Ar methods gives north-to-south ages from these sites of 31.3 ± 0.6, 33 ± 5, 21.5 ± 1.0 and 26.3 ± 0.1 Ma.
    [Show full text]
  • Protea Seamount Cluster 2020
    Front cover image credits: ACEP, Linda Harris, Steve Benjamin, Geoff Spiby, Melanie Wells Protea Seamount Cluster Proposed EBSA Description Abstract The Protea Seamount Cluster is in the south Atlantic abyss off the SSW flank of the Agulhas continental shelf, within the South African EEZ. It is a unique feature in that it is the only seamount cluster in the south Atlantic abyss in South Africa’s EEZ. The seamounts support more productivity and diversity compared to adjacent sites, and offer a site for migratory species to aggregate around. Notably, the Protea Seamount Cluster contains vulnerable and sensitive ecosystems and species, some of which are threatened, e.g. the site is visited by regionally Critically Endangered leatherback turtles. It is in good condition given the currently low anthropogenic pressure in the area, promoting the importance of its protection. This EBSA is particularly relevant for its: Uniqueness and rarity; Importance for threatened or declining species and habitats; Vulnerability and sensitivity; and Naturalness. Introduction The Protea Seamount Cluster focus area lies on the SSW flank of the Agulhas continental shelf: an oceanic plateau that extends several hundreds of kilometres south of South Africa. The focus area is south west of the Browns Bank EBSA, entirely within the South African EEZ. The site includes the base of the lower slope, but falls mainly within the south Atlantic abyss. Late Eocene volcanism created the seamount cluster in this focus area, including Protea and Argentina Seamounts (among others). The Agulhas Current, which flows south-westward along the eastern coast of South Africa, has its retroflection in this area.
    [Show full text]
  • Western South Pacific Regional Workshop in Nadi, Fiji, 22 to 25 November 2011
    SPINE .24” 1 1 Ecologically or Biologically Significant Secretariat of the Convention on Biological Diversity 413 rue St-Jacques, Suite 800 Tel +1 514-288-2220 Marine Areas (EBSAs) Montreal, Quebec H2Y 1N9 Fax +1 514-288-6588 Canada [email protected] Special places in the world’s oceans The full report of this workshop is available at www.cbd.int/wsp-ebsa-report For further information on the CBD’s work on ecologically or biologically significant marine areas Western (EBSAs), please see www.cbd.int/ebsa south Pacific Areas described as meeting the EBSA criteria at the CBD Western South Pacific Regional Workshop in Nadi, Fiji, 22 to 25 November 2011 EBSA WSP Cover-F3.indd 1 2014-09-16 2:28 PM Ecologically or Published by the Secretariat of the Convention on Biological Diversity. Biologically Significant ISBN: 92-9225-558-4 Copyright © 2014, Secretariat of the Convention on Biological Diversity. Marine Areas (EBSAs) The designations employed and the presentation of material in this publication do not imply the expression of any opinion whatsoever on the part of the Secretariat of the Convention on Biological Diversity concerning the legal status of any country, territory, city or area or of its authorities, or concerning the delimitation of Special places in the world’s oceans its frontiers or boundaries. The views reported in this publication do not necessarily represent those of the Secretariat of the Areas described as meeting the EBSA criteria at the Convention on Biological Diversity. CBD Western South Pacific Regional Workshop in Nadi, This publication may be reproduced for educational or non-profit purposes without special permission from the copyright holders, provided acknowledgement of the source is made.
    [Show full text]
  • Seal Quality and Distribution in the Southern Taranaki Basin Late Cretaceous to Eocene Section and Implications for Hydrocarbon Trapping
    SEAL QUALITY AND DISTRIBUTION IN THE SOUTHERN TARANAKI BASIN LATE CRETACEOUS TO EOCENE SECTION AND IMPLICATIONS FOR HYDROCARBON TRAPPING ________________________________________________________________ A thesis submitted in partial fulfilment of the requirements for the Degree of Master of Science in Geology in the University of Canterbury by J. Coyle University of Canterbury 2018 ________________________________________________________________ Contents Abstract ................................................................................................................................................... V Acknowledgments .................................................................................................................................. VI 1. Introduction .................................................................................................................................... 1 1.1 Project Aims and Outline ........................................................................................................ 1 1.2 Geological Overview ............................................................................................................... 4 1.3 Seals ........................................................................................................................................ 5 1.4 Previous and Current Exploration ........................................................................................... 6 2. Overview of the Taranaki Basin .....................................................................................................
    [Show full text]
  • Breathing New Life Into Postmortem Analysis: the Testing And
    BREATHING NEW LIFE INTO POSTMORTEM ANALYSIS: THE TESTING AND FORMALIZATION OF A METHODOLOGY FOR THE IDENTIFICATION OF KEY FAILURE MODES IN DRY HOLES by Jack M. Samis A thesis submitted to the Faculty and the Board of Trustees of the Colorado School of Mines in partial fulfillment of the requirements for the degree of Master of Science (Geology). Golden, Colorado Date __________________________ Signed: __________________________ Jack M. Samis Signed: __________________________ Alexei V. Milkov Thesis Advisor Golden, Colorado Date __________________________ Signed: __________________________ Dr. Steve Enders Professor and Head Department of Geology and Geological Engineering ii ABSTRACT The petroleum exploration industry relies on various subsurface data and interpretations to minimize risk and uncertainties and maximize gains. Dry holes provide a wealth of useful subsurface information. However, far too often a company drills a dry hole and either does not conduct a postdrill analysis (postmortem), or incorrectly determines the failure mode. The purpose of this study is to formalize and test the applicability of a postdrill methodology (a decision tree) that helps identify the main failure mode for dry segments tested by conventional wells. Use of this decision tree allows the interpreter to evaluate and identify specific failure modes such as reservoir presence, reservoir deliverability, structure, seal, source maturity, and migration. The decision tree was tested on three exploration wells drilled in the Taranaki Basin, offshore New Zealand. Each segment’s key failure mode was identified based on the comprehensive, integrated evaluation of both pre- and postdrill reports, seismic data, well logs, geochemical analysis of gases and source rocks, and other materials freely available through the New Zealand government.
    [Show full text]