DOCSLIB.ORG

Pannotia's Mantle Signature: the Quest for Supercontinent Identification

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Pannotia's Mantle Signature: the Quest for Supercontinent Identification Downloaded from http://sp.lyellcollection.org/ by guest on September 30, 2021 Accepted Manuscript Geological Society, London, Special Publications Pannotia's mantle signature: the quest for supercontinent identification Philip J. Heron, J. Brendan Murphy, R. Damian Nance & R. N. Pysklywec DOI: https://doi.org/10.1144/SP503-2020-7 To access the most recent version of this article, please click the DOI URL in the line above Received 10 January 2020 Revised 2 July 2020 Accepted 6 July 2020 © 2020 The Author(s). This is an Open Access article distributed under the terms of the Creative Commons Attribution 4.0 License (http://creativecommons.org/licenses/by/4.0/). Published by The Geological Society of London. Publishing disclaimer: www.geolsoc.org.uk/pub_ethics When citing this article please include the DOI provided above. Manuscript version: Accepted Manuscript This is a PDF of an unedited manuscript that has been accepted for publication. The manuscript will undergo copyediting, typesetting and correction before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the book series pertain. Although reasonable efforts have been made to obtain all necessary permissions from third parties to include their copyrighted content within this article, their full citation and copyright line may not be present in this Accepted Manuscript version. Before using any content from this article, please refer to the Version of Record once published for full citation and copyright details, as permissions may be required. Downloaded from http://sp.lyellcollection.org/ by guest on September 30, 2021 Pannotia's mantle signature: the quest for supercontinent identification Philip J. Heron1*, J. Brendan Murphy2, R. Damian Nance3, 4, R. N. Pysklywec5. 1Department of Earth Sciences, Durham University, Durham, England. 2Department of Earth Sciences, St. Francis Xavier University, Antigonish, Nova Scotia, Canada. 3Department of Geological Sciences, Ohio University, Ohio, USA. 4Department of Earth & Planetary Sciences, Yale University, Connecticut, USA. 5Department of Earth Sciences, University of Toronto, Toronto, Ontario, Canada. * Corresponding author (email: [email protected]). Abstract: A supercontinent is generally considered to reflect the assembly of all, or most, of the Earth’s continental lithosphere. Previous studies have used geological, atmospheric, and biogenic ‘geomarkers’ to supplement supercontinent identification. However, there is no formal definition of how much continental material is required to be assembled, or indeed which geomarkers need to be present. Pannotia is a hypothesized landmass that existed in the interval ~0.65-0.54 Ga and was comprised of Gondwana, Laurentia, Baltica, and possibly Siberia.ACCEPTED Although Pannotia was considerably MANUSCRIPT smaller than Pangaea (and also fleeting in its existence), the presence of geomarkers in the geological record support its identification as a supercontinent. Using 3-D mantle convection models, we simulate the evolution of the mantle in response to the convergence leading to amalgamation of Rodinia and Pangaea. We then compare this supercontinent ‘fingerprint’ to Pannotian activity. For the first time, we Downloaded from http://sp.lyellcollection.org/ by guest on September 30, 2021 show that Pannotian continental convergence could have generated a mantle signature in keeping with that of a simulated supercontinent. As a result, we posit that any formal identification of a supercontinent must take into consideration the thermal evolution of the mantle associated with convergence leading to continental amalgamation, rather than simply the size of the connected continental landmass. The formation of supercontinent Pangaea (Figure 1a) had a profound effect on the thermal evolution of the mantle. An increase in deep mantle upwelling and plume formation is thought to follow supercontinent formation (Gurnis 1988; Zhong & Gurnis 1993; Lowman & Jarvis 1993; Zhong et al. 2007; Li & Zhong 2009; Yoshida 2010; Heron & Lowman 2010; Yoshida 2013; Gamal el Dien, 2019), with large igneous provinces (LIPs) being the surface manifestations of such plumes (e.g. Yale & Carpenter 1998; Courtillot et al. 1999; Ernst et al. 2005; Ernst & Bleeker 2010; Sobolev et al. 2011). Additional “geomarkers” (see Nance et al., 1986) have also been identified for supercontinent Pangaea, including global-scale orogenesis (Nance et al., 1988; Santosh, 2010a; Condie, 2011; Müller et al. 2013), crustal growth (Hawkesworth et al. 2010, 2016), the distribution of metamorphic belts (Brown, 2007) and mineral deposits (Goldfarb et al. 2010), rapid climate swings (Hoffman et al. 1998; Strand 2012; Young 2012), major events in the evolution of life and the atmosphere (Lindsay & Brasier 2002; Santosh 2010b; Knoll, 2013; Melezhik et al. 2013), biogeochemical cycles (NanceACCEPTED et al., 1986), and profound sea-level MANUSCRIPT change (Worsley et al. 1984; Nance and Murphy, 2013). Such geomarkers are interpreted as signals of supercontinent convergence leading to amalgamation and may be useful proxies for identifying the existence of previous supercontinents for which palaeocontintental reconstructions may be less refined (Nance and Murphy, 2019). Downloaded from http://sp.lyellcollection.org/ by guest on September 30, 2021 Although their ages of amalgamation and breakup are still being refined, based on the identification of these markers in the geological record, a number of pre-Pangaean supercontinents have been proposed. Rodinia (Figure 1b), with Laurentia at its centre, was formed by 1.1-0.9 Ga global-scale orogenesis (Hoffman 1991; Dalziel 1991; Moores 1991; Torsvik 2003; Li et al. 2004, 2008). It was fully assembled by approximately 900 Ma and is believed to have rifted apart in two separate episodes (~0.85-0.70 Ga and ~0.62-0.54 Ga) (Li et al. 2008, 2013; Li & Evans 2011). Earlier supercontinents include Nuna/Columbia (Hoffman, 1997; Rogers and Santosh, 2002) whose existence is most recently dated at ~1.6- 1.4 Ga (e.g., Pehrsson et al., 2015), Kenorland (Williams et al., 1991) thought to have existed during the interval ~2.7-2.5 Ga, and possibly Ur (~3.0 Ga), although the latter is better described as a supercraton (i.e. transient, late Archean landmasses which broke up to form cratons, e.g. Bleeker 2003). Although there are geological markers for supercontinent assembly (e.g., Nance et al., 2014), no formal system exists for supercontinent identification, as a result of which there is no formal definition of a supercontinent (e.g., Meert 2012). Even a basic understanding of how much contiguous landmass is required is open to debate. For example, Meert (2012) proposed a figure of 75% of available continent crust but, as pointed out by Nance and Murphy (2019), this is both difficult to estimate and views supercontinents as objects rather than the consequence of a geodynamic process. The statusACCEPTED of Pannotia (~0.65-0.54 Ga; Gondwana-Laurentia-Baltica MANUSCRIPT and possibly Siberia, Figure 1c-f), is an example of the ongoing debate about what constitutes a supercontinent (see Murphy et al., this volume; Evans, this volume). Given the uncertainties inherent in Neoproterozoic palaeogeographic reconstructions, Nance and Murphy (2019) argue that Pannotia’s status as a supercontinent is apparent from a number of ‘supercontinent’ markers around the time of its proposed formation (e.g., global-scale orogeny, rapid continental Downloaded from http://sp.lyellcollection.org/ by guest on September 30, 2021 growth, profound changes in the chemistry of the oceans and atmosphere, rapid and dramatic climate swings, as well as an explosion in biological activity; Nance et al., 1986; Hoffman 1991; Hoffman et al., 1998; Maruyama and Santosh, 2008; Knoll, 2013). However, there is general agreement that Pannotia’s size and duration were significantly less than that of Pangaea, drawing controversy as to whether it can be classified as a unique supercontinent or was simply part of Rodinia after initial breakup (e.g., Mitchell et al., 2012; Li et al., 2019). An area of Pannotian dynamics that has not been fully explored is the response of the mantle to the continental convergence leading to its amalgamation. Late Neoproterozoic continental convergence and protracted subduction leading to the assembly of the Gondwanan portion of Pannotia is strongly indicated by widespread “Pan-African” collisional orogenic activity between 0.62 and 0.53 Ga (e.g. Li et al., 2008; Merdith et al., 2017). Investigating the effect of continental convergence and assembly on Late Neoproterozoic-Early Paleozoic (0.6-0.5 Ga) mantle convection patterns, could allow for supercontinent identification through its impact on mantle dynamics (e.g., Heron, 2019). Furthermore, as the legacy of such an impact would affect Palaeozoic mantle convection patterns, it would also need to be factored into models purported to explain the amalgamation of Pangaea. The Central Iapetus Magmatic Province (CIMP, Figure 1e-f) is one potential manifestation of changes in deep mantle circulation that may have been an outcome of continental convergence (in a similar way to the Central Atlantic Magmatic Province and the convergenceACCEPTED of Pangaea). CIMP comprises MANUSCRIPTseveral large igneous provinces (LIPs) and predominantly consists of mafic dyke swarms, basalts, bimodal basalt-rhyolite complexes, lamprophyres and carbonatites (Kamo et al., 1995; Higgins
Load more

Recommended publications
  • Kinematic Reconstruction of the Caribbean Region Since the Early Jurassic
    Earth-Science Reviews 138 (2014) 102–136 Contents lists available at ScienceDirect Earth-Science Reviews journal homepage: www.elsevier.com/locate/earscirev Kinematic reconstruction of the Caribbean region since the Early Jurassic Lydian M. Boschman a,⁎, Douwe J.J. van Hinsbergen a, Trond H. Torsvik b,c,d, Wim Spakman a,b, James L. Pindell e,f a Department of Earth Sciences, Utrecht University, Budapestlaan 4, 3584 CD Utrecht, The Netherlands b Center for Earth Evolution and Dynamics (CEED), University of Oslo, Sem Sælands vei 24, NO-0316 Oslo, Norway c Center for Geodynamics, Geological Survey of Norway (NGU), Leiv Eirikssons vei 39, 7491 Trondheim, Norway d School of Geosciences, University of the Witwatersrand, WITS 2050 Johannesburg, South Africa e Tectonic Analysis Ltd., Chestnut House, Duncton, West Sussex, GU28 OLH, England, UK f School of Earth and Ocean Sciences, Cardiff University, Park Place, Cardiff CF10 3YE, UK article info abstract Article history: The Caribbean oceanic crust was formed west of the North and South American continents, probably from Late Received 4 December 2013 Jurassic through Early Cretaceous time. Its subsequent evolution has resulted from a complex tectonic history Accepted 9 August 2014 governed by the interplay of the North American, South American and (Paleo-)Pacific plates. During its entire Available online 23 August 2014 tectonic evolution, the Caribbean plate was largely surrounded by subduction and transform boundaries, and the oceanic crust has been overlain by the Caribbean Large Igneous Province (CLIP) since ~90 Ma. The consequent Keywords: absence of passive margins and measurable marine magnetic anomalies hampers a quantitative integration into GPlates Apparent Polar Wander Path the global circuit of plate motions.
    [Show full text]
  • Playing Jigsaw with Large Igneous Provinces a Plate Tectonic
    PUBLICATIONS Geochemistry, Geophysics, Geosystems RESEARCH ARTICLE Playing jigsaw with Large Igneous Provinces—A plate tectonic 10.1002/2015GC006036 reconstruction of Ontong Java Nui, West Pacific Key Points: Katharina Hochmuth1, Karsten Gohl1, and Gabriele Uenzelmann-Neben1 New plate kinematic reconstruction of the western Pacific during the 1Alfred-Wegener-Institut Helmholtz-Zentrum fur€ Polar- und Meeresforschung, Bremerhaven, Germany Cretaceous Detailed breakup scenario of the ‘‘Super’’-Large Igneous Province Abstract The three largest Large Igneous Provinces (LIP) of the western Pacific—Ontong Java, Manihiki, Ontong Java Nui Ontong Java Nui ‘‘Super’’-Large and Hikurangi Plateaus—were emplaced during the Cretaceous Normal Superchron and show strong simi- Igneous Province as result of larities in their geochemistry and petrology. The plate tectonic relationship between those LIPs, herein plume-ridge interaction referred to as Ontong Java Nui, is uncertain, but a joined emplacement was proposed by Taylor (2006). Since this hypothesis is still highly debated and struggles to explain features such as the strong differences Correspondence to: in crustal thickness between the different plateaus, we revisited the joined emplacement of Ontong Java K. Hochmuth, [email protected] Nui in light of new data from the Manihiki Plateau. By evaluating seismic refraction/wide-angle reflection data along with seismic reflection records of the margins of the proposed ‘‘Super’’-LIP, a detailed scenario Citation: for the emplacement and the initial phase of breakup has been developed. The LIP is a result of an interac- Hochmuth, K., K. Gohl, and tion of the arriving plume head with the Phoenix-Pacific spreading ridge in the Early Cretaceous. The G.
    [Show full text]
  • Assembly, Configuration, and Break-Up History of Rodinia
    Author's personal copy Available online at www.sciencedirect.com Precambrian Research 160 (2008) 179–210 Assembly, configuration, and break-up history of Rodinia: A synthesis Z.X. Li a,g,∗, S.V. Bogdanova b, A.S. Collins c, A. Davidson d, B. De Waele a, R.E. Ernst e,f, I.C.W. Fitzsimons g, R.A. Fuck h, D.P. Gladkochub i, J. Jacobs j, K.E. Karlstrom k, S. Lu l, L.M. Natapov m, V. Pease n, S.A. Pisarevsky a, K. Thrane o, V. Vernikovsky p a Tectonics Special Research Centre, School of Earth and Geographical Sciences, The University of Western Australia, Crawley, WA 6009, Australia b Department of Geology, Lund University, Solvegatan 12, 223 62 Lund, Sweden c Continental Evolution Research Group, School of Earth and Environmental Sciences, University of Adelaide, Adelaide, SA 5005, Australia d Geological Survey of Canada (retired), 601 Booth Street, Ottawa, Canada K1A 0E8 e Ernst Geosciences, 43 Margrave Avenue, Ottawa, Canada K1T 3Y2 f Department of Earth Sciences, Carleton U., Ottawa, Canada K1S 5B6 g Tectonics Special Research Centre, Department of Applied Geology, Curtin University of Technology, GPO Box U1987, Perth, WA 6845, Australia h Universidade de Bras´ılia, 70910-000 Bras´ılia, Brazil i Institute of the Earth’s Crust SB RAS, Lermontova Street, 128, 664033 Irkutsk, Russia j Department of Earth Science, University of Bergen, Allegaten 41, N-5007 Bergen, Norway k Department of Earth and Planetary Sciences, Northrop Hall University of New Mexico, Albuquerque, NM 87131, USA l Tianjin Institute of Geology and Mineral Resources, CGS, No.
    [Show full text]
  • Helicobacter Pylori's Historical Journey Through Siberia and the Americas
    Helicobacter pylori’s historical journey through Siberia and the Americas Yoshan Moodleya,1,2, Andrea Brunellib,1, Silvia Ghirottoc,1, Andrey Klyubind, Ayas S. Maadye, William Tynef, Zilia Y. Muñoz-Ramirezg, Zhemin Zhouf, Andrea Manicah, Bodo Linzi, and Mark Achtmanf aDepartment of Zoology, University of Venda, Thohoyandou 0950, Republic of South Africa; bDepartment of Life Sciences and Biotechnology, University of Ferrara, 44121 Ferrara, Italy; cDepartment of Mathematics and Computer Science, University of Ferrara, 44121 Ferrara, Italy; dDepartment of Molecular Biology and Genetics, Research Institute for Physical-Chemical Medicine, 119435 Moscow, Russia; eDepartment of Diagnostic and Operative Endoscopy, Pirogov National Medical and Surgical Center, 105203 Moscow, Russia; fWarwick Medical School, University of Warwick, Coventry CV4 7AL, United Kingdom; gLaboratorio de Bioinformática y Biotecnología Genómica, Escuela Nacional de Ciencias Biológicas, Unidad Profesional Lázaro Cárdenas, Instituto Politécnico Nacional, 11340 Mexico City, Mexico; hDepartment of Zoology, University of Cambridge, Cambridge CB2 3EJ, United Kingdom; and iDepartment of Biology, Division of Microbiology, Friedrich Alexander University Erlangen-Nuremberg, 91058 Erlangen, Germany Edited by Daniel Falush, University of Bath, Bath, United Kingdom, and accepted by Editorial Board Member W. F. Doolittle April 30, 2021 (received for review July 22, 2020) The gastric bacterium Helicobacter pylori shares a coevolutionary speakers). However, H. pylori’s presence, diversity, and structure history with humans that predates the out-of-Africa diaspora, and in northern Eurasia are still unknown. This vast region, hereafter the geographical specificities of H. pylori populations reflect mul- Siberia, extends from the Ural Mountains in the west to the tiple well-known human migrations. We extensively sampled H.
    [Show full text]
  • Plate Tectonic Regulation of Global Marine Animal Diversity
    Plate tectonic regulation of global marine animal diversity Andrew Zaffosa,1, Seth Finneganb, and Shanan E. Petersa aDepartment of Geoscience, University of Wisconsin–Madison, Madison, WI 53706; and bDepartment of Integrative Biology, University of California, Berkeley, CA 94720 Edited by Neil H. Shubin, The University of Chicago, Chicago, IL, and approved April 13, 2017 (received for review February 13, 2017) Valentine and Moores [Valentine JW, Moores EM (1970) Nature which may be complicated by spatial and temporal inequities in 228:657–659] hypothesized that plate tectonics regulates global the quantity or quality of samples (11–18). Nevertheless, many biodiversity by changing the geographic arrangement of conti- major features in the fossil record of biodiversity are consis- nental crust, but the data required to fully test the hypothesis tently reproducible, although not all have universally accepted were not available. Here, we use a global database of marine explanations. In particular, the reasons for a long Paleozoic animal fossil occurrences and a paleogeographic reconstruction plateau in marine richness and a steady rise in biodiversity dur- model to test the hypothesis that temporal patterns of continen- ing the Late Mesozoic–Cenozoic remain contentious (11, 12, tal fragmentation have impacted global Phanerozoic biodiversity. 14, 19–22). We find a positive correlation between global marine inverte- Here, we explicitly test the plate tectonic regulation hypothesis brate genus richness and an independently derived quantitative articulated by Valentine and Moores (1) by measuring the extent index describing the fragmentation of continental crust during to which the fragmentation of continental crust covaries with supercontinental coalescence–breakup cycles. The observed posi- global genus-level richness among skeletonized marine inverte- tive correlation between global biodiversity and continental frag- brates.
    [Show full text]
  • African Families in a Global Context
    RR13X.book Page 1 Monday, November 14, 2005 2:20 PM RESEARCH REPORT NO. 131 AFRICAN FAMILIES IN A GLOBAL CONTEXT Edited by Göran Therborn Nordiska Afrikainstitutet, Uppsala 2006 RR13X.book Page 2 Monday, November 14, 2005 2:20 PM Indexing terms Demographic change Family Family structure Gender roles Social problems Africa Ghana Nigeria South Africa African Families in a Global Context Second edition © the authors and Nordiska Afrikainstitutet, 2004 Language checking: Elaine Almén ISSN 1104-8425 ISBN 91-7106-561-X (print) 91-7106-562-8 (electronic) Printed in Sweden by Elanders Infologistics Väst AB, Göteborg 2006 RR13X.book Page 3 Monday, November 14, 2005 2:20 PM Contents Preface . 5 Author presentations . 7 Introduction Globalization, Africa, and African Family Pattern . 9 Göran Therborn 1. African Families in a Global Context. 17 Göran Therborn 2. Demographic Innovation and Nutritional Catastrophe: Change, Lack of Change and Difference in Ghanaian Family Systems . 49 Christine Oppong 3. Female (In)dependence and Male Dominance in Contemporary Nigerian Families . 79 Bola Udegbe 4. Globalization and Family Patterns: A View from South Africa . 98 Susan C. Ziehl RR13X.book Page 4 Monday, November 14, 2005 2:20 PM RR13X.book Page 5 Monday, November 14, 2005 2:20 PM Preface In the mid-1990s the Swedish Council for Planning and Coordination of Research (Forskningsrådsnämnden – FRN) – subsequently merged into the Council of Sci- ence (Vetenskaprådet) – established a national, interdisciplinary research committee on Global Processes. The Committee has been strongly committed to a multidi- mensional and multidisciplinary approach to globalization and global processes and to using regional perspectives.
    [Show full text]
  • Paleomagnetism and U-Pb Geochronology of the Late Cretaceous Chisulryoung Volcanic Formation, Korea
    Jeong et al. Earth, Planets and Space (2015) 67:66 DOI 10.1186/s40623-015-0242-y FULL PAPER Open Access Paleomagnetism and U-Pb geochronology of the late Cretaceous Chisulryoung Volcanic Formation, Korea: tectonic evolution of the Korean Peninsula Doohee Jeong1, Yongjae Yu1*, Seong-Jae Doh2, Dongwoo Suk3 and Jeongmin Kim4 Abstract Late Cretaceous Chisulryoung Volcanic Formation (CVF) in southeastern Korea contains four ash-flow ignimbrite units (A1, A2, A3, and A4) and three intervening volcano-sedimentary layers (S1, S2, and S3). Reliable U-Pb ages obtained for zircons from the base and top of the CVF were 72.8 ± 1.7 Ma and 67.7 ± 2.1 Ma, respectively. Paleomagnetic analysis on pyroclastic units yielded mean magnetic directions and virtual geomagnetic poles (VGPs) as D/I = 19.1°/49.2° (α95 =4.2°,k = 76.5) and VGP = 73.1°N/232.1°E (A95 =3.7°,N =3)forA1,D/I = 24.9°/52.9° (α95 =5.9°,k =61.7)and VGP = 69.4°N/217.3°E (A95 =5.6°,N=11) for A3, and D/I = 10.9°/50.1° (α95 =5.6°,k = 38.6) and VGP = 79.8°N/ 242.4°E (A95 =5.0°,N = 18) for A4. Our best estimates of the paleopoles for A1, A3, and A4 are in remarkable agreement with the reference apparent polar wander path of China in late Cretaceous to early Paleogene, confirming that Korea has been rigidly attached to China (by implication to Eurasia) at least since the Cretaceous. The compiled paleomagnetic data of the Korean Peninsula suggest that the mode of clockwise rotations weakened since the mid-Jurassic.
    [Show full text]
  • Back Matter (PDF)
    Index Page numbers in italic refer to tables, and those in bold to figures. accretionary orogens, defined 23 Namaqua-Natal Orogen 435-8 Africa, East SW Angola and NW Botswana 442 Congo-Sat Francisco Craton 4, 5, 35, 45-6, 49, 64 Umkondo Igneous Province 438-9 palaeomagnetic poles at 1100-700 Ma 37 Pan-African orogenic belts (650-450 Ma) 442-50 East African(-Antarctic) Orogen Damara-Lufilian Arc-Zambezi Belt 3, 435, accretion and deformation, Arabian-Nubian Shield 442-50 (ANS) 327-61 Katangan basaltic rocks 443,446 continuation of East Antarctic Orogen 263 Mwembeshi Shear Zone 442 E/W Gondwana suture 263-5 Neoproterozoic basin evolution and seafloor evolution 357-8 spreading 445-6 extensional collapse in DML 271-87 orogenesis 446-51 deformations 283-5 Ubendian and Kibaran Belts 445 Heimefront Shear Zone, DML 208,251, 252-3, within-plate magmatism and basin initiation 443-5 284, 415,417 Zambezi Belt 27,415 structural section, Neoproterozoic deformation, Zambezi Orogen 3, 5 Madagascar 365-72 Zambezi-Damara Belt 65, 67, 442-50 see also Arabian-Nubian Shield (ANS); Zimbabwe Belt, ophiolites 27 Mozambique Belt Zimbabwe Craton 427,433 Mozambique Belt evolution 60-1,291, 401-25 Zimbabwe-Kapvaal-Grunehogna Craton 42, 208, 250, carbonates 405.6 272-3 Dronning Mand Land 62-3 see also Pan-African eclogites and ophiolites 406-7 Africa, West 40-1 isotopic data Amazonia-Rio de la Plata megacraton 2-3, 40-1 crystallization and metamorphic ages 407-11 Birimian Orogen 24 Sm-Nd (T DM) 411-14 A1-Jifn Basin see Najd Fault System lithologies 402-7 Albany-Fraser-Wilkes
    [Show full text]
  • 1 Introduction Gondwana
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Sydney eScholarship Regional plate tectonic reconstructions of the Indian Ocean Thesis Submitted in fulfilment of the requirements for the degree of Doctor of Philosophy Ana Gibbons School of Geosciences 2012 Supervised by Professor R. Dietmar Müller and Dr Joanne Whittaker The University of Sydney, PhD Thesis, Ana Gibbons, 2012 - Introduction DECLARATION I declare that this thesis contains less than 100,000 words and contains no work that has been submitted for a higher degree at any other university or institution. No animal or ethical approvals were applicable to this study. The use of any published written material or data has been duly acknowledged. Ana Gibbons ii The University of Sydney, PhD Thesis, Ana Gibbons, 2012 - Introduction ACKNOWLEDGEMENTS I would like to thank my supervisors for their endless encouragement, generosity, patience, and not least of all their expertise and ingenuity. I have thoroughly benefitted from working with them and cannot imagine a better supervisory team. I also thank Maria Seton, Carmen Gaina and Sabin Zahirovic for their help and encouragement. I thank Statoil (Norway), the Petroleum Exploration Society of Australia (PESA) and the School of Geosciences, University of Sydney for support. I am extremely grateful to Udo Barckhausen, Kaj Hoernle, Reinhard Werner, Paul Van Den Bogaard and all staff and crew of the CHRISP research cruise for a very informative and fun collaboration, which greatly refined this first chapter of this thesis. I also wish to thank Dr Yatheesh Vadakkeyakath from the National Institute of Oceanography, Goa, India, for his thorough review, which considerably improved the overall model and quality of the second chapter.
    [Show full text]
  • Geologic History of Siletzia, a Large Igneous Province in the Oregon And
    Geologic history of Siletzia, a large igneous province in the Oregon and Washington Coast Range: Correlation to the geomagnetic polarity time scale and implications for a long-lived Yellowstone hotspot Wells, R., Bukry, D., Friedman, R., Pyle, D., Duncan, R., Haeussler, P., & Wooden, J. (2014). Geologic history of Siletzia, a large igneous province in the Oregon and Washington Coast Range: Correlation to the geomagnetic polarity time scale and implications for a long-lived Yellowstone hotspot. Geosphere, 10 (4), 692-719. doi:10.1130/GES01018.1 10.1130/GES01018.1 Geological Society of America Version of Record http://cdss.library.oregonstate.edu/sa-termsofuse Downloaded from geosphere.gsapubs.org on September 10, 2014 Geologic history of Siletzia, a large igneous province in the Oregon and Washington Coast Range: Correlation to the geomagnetic polarity time scale and implications for a long-lived Yellowstone hotspot Ray Wells1, David Bukry1, Richard Friedman2, Doug Pyle3, Robert Duncan4, Peter Haeussler5, and Joe Wooden6 1U.S. Geological Survey, 345 Middlefi eld Road, Menlo Park, California 94025-3561, USA 2Pacifi c Centre for Isotopic and Geochemical Research, Department of Earth, Ocean and Atmospheric Sciences, 6339 Stores Road, University of British Columbia, Vancouver, BC V6T 1Z4, Canada 3Department of Geology and Geophysics, University of Hawaii at Manoa, 1680 East West Road, Honolulu, Hawaii 96822, USA 4College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, 104 CEOAS Administration Building, Corvallis, Oregon 97331-5503, USA 5U.S. Geological Survey, 4210 University Drive, Anchorage, Alaska 99508-4626, USA 6School of Earth Sciences, Stanford University, 397 Panama Mall Mitchell Building 101, Stanford, California 94305-2210, USA ABSTRACT frames, the Yellowstone hotspot (YHS) is on southern Vancouver Island (Canada) to Rose- or near an inferred northeast-striking Kula- burg, Oregon (Fig.
    [Show full text]
  • Connecting the Deep Earth and the Atmosphere
    In Mantle Convection and Surface Expression (Cottaar, S. et al., eds.) AGU Monograph 2020 (in press) Connecting the Deep Earth and the Atmosphere Trond H. Torsvik1,2, Henrik H. Svensen1, Bernhard Steinberger3,1, Dana L. Royer4, Dougal A. Jerram1,5,6, Morgan T. Jones1 & Mathew Domeier1 1Centre for Earth Evolution and Dynamics (CEED), University of Oslo, 0315 Oslo, Norway; 2School of Geosciences, University of Witwatersrand, Johannesburg 2050, South Africa; 3Helmholtz Centre Potsdam, GFZ, Telegrafenberg, 14473 Potsdam, Germany; 4Department of Earth and Environmental Sciences, Wesleyan University, Middletown, Connecticut 06459, USA; 5DougalEARTH Ltd.1, Solihull, UK; 6Visiting Fellow, Earth, Environmental and Biological Sciences, Queensland University of Technology, Brisbane, Queensland, Australia. Abstract Most hotspots, kimberlites, and large igneous provinces (LIPs) are sourced by plumes that rise from the margins of two large low shear-wave velocity provinces in the lowermost mantle. These thermochemical provinces have likely been quasi-stable for hundreds of millions, perhaps billions of years, and plume heads rise through the mantle in about 30 Myr or less. LIPs provide a direct link between the deep Earth and the atmosphere but environmental consequences depend on both their volumes and the composition of the crustal rocks they are emplaced through. LIP activity can alter the plate tectonic setting by creating and modifying plate boundaries and hence changing the paleogeography and its long-term forcing on climate. Extensive blankets of LIP-lava on the Earth’s surface can also enhance silicate weathering and potentially lead to CO2 drawdown (cooling), but we find no clear relationship between LIPs and post-emplacement variation in atmospheric CO2 proxies on very long (>10 Myrs) time- scales.
    [Show full text]
  • Plate Tectonics
    Plate tectonics tive motion determines the type of boundary; convergent, divergent, or transform. Earthquakes, volcanic activity, mountain-building, and oceanic trench formation occur along these plate boundaries. The lateral relative move- ment of the plates typically varies from zero to 100 mm annually.[2] Tectonic plates are composed of oceanic lithosphere and thicker continental lithosphere, each topped by its own kind of crust. Along convergent boundaries, subduction carries plates into the mantle; the material lost is roughly balanced by the formation of new (oceanic) crust along divergent margins by seafloor spreading. In this way, the total surface of the globe remains the same. This predic- The tectonic plates of the world were mapped in the second half of the 20th century. tion of plate tectonics is also referred to as the conveyor belt principle. Earlier theories (that still have some sup- porters) propose gradual shrinking (contraction) or grad- ual expansion of the globe.[3] Tectonic plates are able to move because the Earth’s lithosphere has greater strength than the underlying asthenosphere. Lateral density variations in the mantle result in convection. Plate movement is thought to be driven by a combination of the motion of the seafloor away from the spreading ridge (due to variations in topog- raphy and density of the crust, which result in differences in gravitational forces) and drag, with downward suction, at the subduction zones. Another explanation lies in the different forces generated by the rotation of the globe and the tidal forces of the Sun and Moon. The relative im- portance of each of these factors and their relationship to each other is unclear, and still the subject of much debate.
    [Show full text]