DOCSLIB.ORG

Major Element, Trace Element, and Isotopic Composition of Emperor Seamount Chain and Ontong Java Plateau Basalts

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Major Element, Trace Element, and Isotopic Composition of Emperor Seamount Chain and Ontong Java Plateau Basalts MAJOR ELEMENT, TRACE ELEMENT, AND ISOTOPIC COMPOSITION OF EMPEROR SEAMOUNT CHAIN AND ONTONG JAVA PLATEAU BASALTS A Dissertation Submitted to the Graduate School of the University of Notre Dame in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy by John T. Shafer, B.S. Clive R. Neal, Director Graduate Program in Civil Engineering and Geological Sciences Notre Dame, Indiana December 2006 This document is in the public domain. MAJOR ELEMENT, TRACE ELEMENT, AND ISOTOPIC COMPOSITION OF EMPEROR SEAMOUNT CHAIN AND ONTONG JAVA PLATEAU BASALTS Abstract by John T. Shafer The Ontong Java Plateau (OJP) and the Hawaiian Ridge-Emperor Seamount Chain (HR-ESC) are two of the largest volcanic structures on Earth. As the OJP covers an area of more than 2 × 106 km2, the plateau represents the largest known magmatic event in Earth’s history. Equally impressive, the HR-ESC stretches for more than 6,000 km through the north-central Pacific Ocean. Despite the magnitude of these events, the chemistry of significant portions of the OJP and the HR-ESC are poorly known to completely unknown. A full understanding of the chemistry of the OJP and the HR-ESC is necessary to make realistic models of their formation. Major element, trace element, platinum group element (PGE), and isotopic ratio analyses have been conducted on samples collected from several locations on both the OJP and the HR-ESC using inductively coupled plasma-optical emis- sion spectroscopy (ICP-OES), ICP-mass spectrometry (ICP-MS), and negative thermal ionization mass spectrometry (NTIMS). Using a combination of the aforementioned analytical techniques, it was dis- covered the OJP has more geochemical variation than previously recognized, es- pecially at the margins of the plateau. The discovery of a previously unknown John T. Shafer lava type from the volcaniclastic succession at Site 1184 on the eastern salient of the OJP and more primitive lava types from basaltic crustal xenoliths suggests that further sampling via deep sea drilling is necessary to better understand the complex origins of the worlds largest igneous province. ESC seamounts have been assumed to undergo similar stages of development as their younger Hawaiian counterparts despite the paucity of non-dredge sam- ples. The investigation of a greater than 300 km thick sequence of basement from Nintoku Seamount confirms that a typical ESC volcano develops in a similar manner to modern Hawaiian volcanoes. PGE and Re/Os isotopic work on three ESC seamounts suggests that both recycled oceanic crust and outer core material contribute to the overall PGE budget in the Hawaiian plume but that it requires unusual melting conditions for both sources to manifest themselves. DEDICATION To my wife and family ii CONTENTS FIGURES.................................... vii TABLES .................................... xi ACRONYMS .................................. xiii ACKNOWLEDGMENTS ........................... xv CHAPTER 1: INTRODUCTION TO LARGE IGNEOUS PROVINCES ANDTHEPROBLEMATHAND .................... 1 1.1 OverviewofProblem ......................... 1 1.1.1 TheOntongJavaPlateau . 1 1.1.2 Hawaiian Ridge-Emperor Seamount Chain . 4 1.2 SolvingtheProblem ......................... 6 CHAPTER 2: THE ONTONG JAVA PLATEAU: GEOLOGICAL SETTING, PETROLOGY, & GEOCHEMISTRY . 7 2.1 Overview................................ 7 2.2 Geological Setting and Physical Geology . 7 2.3 ModelofFormation.......................... 8 2.4 Petrology&Geochemistry . 11 2.5 VolcaniclasticrocksandSite1184 . 15 CHAPTER 3: HAWAIIAN RIDGE-EMPEROR SEAMOUNT CHAIN . 17 3.1 Overview................................ 17 3.2 HistoryofMantlePlumes . 17 3.3 The Hawaiian Ridge-Emperor Seamount Chain . 24 3.3.1 PhysicalGeology ....................... 24 3.3.2 Geochemistry of the Hawaiian Islands . 27 3.3.3 Geochemistry of the Emperor Seamount Chain (ESC) . 34 3.3.4 Movement of the Hawaiian Mantle Plume . 38 3.4 Summary ............................... 39 iii CHAPTER 4: COMPOSITIONAL VARIABILITY IN LAVAS FROM OCEAN DRILLING PROGRAM SITE 1184, ONTONG JAVA PLATEAU . 41 4.1 Samples ................................ 41 4.2 Results................................. 43 4.2.1 Petrography.......................... 43 4.2.2 MajorElements........................ 45 4.2.3 TraceElements ........................ 51 4.2.4 Radiogenicisotoperatios. 58 4.3 Discussion............................... 61 4.3.1 Theinfluenceofalteration . 61 4.3.2 Petrogeneticinterpretations . 69 4.3.3 Sourceregion ......................... 73 4.4 Conclusions .............................. 74 CHAPTER 5: ONTONG JAVA PLATEAU XENOLITHS FROM THE IS- LANDOFMALAITA ........................... 76 5.1 GeologyofMalaitaandtheSolomonIslands . 76 5.2 TheMalaitanAln¨oite. 79 5.3 Previous Work on Aln¨oite Xenoliths . 80 5.4 The Xenolith Suite Studied for this Work . 82 5.5 AnalyticalMethods.......................... 82 5.6 Results................................. 82 5.6.1 Petrography.......................... 82 5.6.1.1 BM/SI-7........................... 83 5.6.1.2 PHN5802.......................... 83 5.6.1.3 PHN3939.......................... 84 5.6.1.4 PHN5765.......................... 85 5.6.1.5 PHN5792.......................... 86 5.6.1.6 PHN5793.......................... 87 5.6.1.7 PHN5843.......................... 88 5.6.1.8 PHN5853.......................... 89 5.6.1.9 PHN5854.......................... 89 5.6.1.10 ST-7............................. 90 5.6.2 MajorElementData . .. .. 92 5.6.3 TraceElementData . .. .. 96 5.6.4 Sr-andNd-IsotopicData. 103 5.6.5 ElectronMicroprobeData . 105 5.7 Discussion ............................... 111 5.7.1 OriginofREEAnomalies . 111 5.7.2 Thermobarometry. 115 5.7.3 Relationship of the Basalt/Gabbro Samples to the OJP . 120 iv 5.8 Conclusions .............................. 125 CHAPTER 6: HAWAIIAN PLUME SOURCE HYBRIDIZATION: EVI- DENCE FROM NINTOKU SEAMOUNT, EMPEROR SEAMOUNT CHAIN ................................... 127 6.1 NintokuSeamount .......................... 127 6.2 Samples ................................ 129 6.3 Results................................. 132 6.3.1 MajorElements. .. .. 132 6.3.2 TraceElements ........................ 137 6.3.3 SrandNdIsotopes . .. .. 148 6.4 Discussion ............................... 152 6.4.1 Chemical and Isotopic Variations with Depth (Stratigraphic Age)intheSite1205DrillCore . 152 6.4.2 Influence of Alteration of Chemistry . 154 6.4.3 Role of Fractional Crystallization and Crystal Accumulation 157 6.4.4 Role of Melting Processes and Source Heterogeneity in Cre- atingVariationWithinNintoku Lavas . 162 6.4.5 Model for the Formation of the Nintoku Post-Shield Basalts 163 6.4.6 A Physical Model for Nintoku Post-Shield Magmatism . 174 6.4.7 Constraints from Sr Isotope Variations with Time on Pet- rogenesis of Hawaiian-Emperor Post-Shield Lavas . 176 6.5 Conclusions .............................. 179 CHAPTER 7: THE PLATINUM GROUP ELEMENT AND RE–OS ISO- TOPIC COMPOSITION OF THE EMPEROR SEAMOUNT CHAIN . 181 7.1 Introduction.............................. 181 7.1.1 DetroitSeamount, ODP Leg 197,Site 1203. 182 7.1.2 Nintoku Seamount, ODPLeg 197, Site 1205 . 183 7.1.3 KokoSeamount, ODPLeg197,Site1206 . 185 7.1.4 PGEsandtheHawaiianPlume . 186 7.2 AnalyticalTechniques . 189 7.3 Results................................. 189 7.3.1 Petrography.......................... 189 7.3.1.1 DetroitSeamount. 189 7.3.1.2 NintokuSeamount . 190 7.3.1.3 KokoSeamount. 190 7.3.2 MajorandTraceElements . 191 7.3.2.1 Detroit Seamount (∼ 81Ma) ............... 195 7.3.2.2 Nintoku Seamount (∼ 56Ma)............... 197 7.3.2.3 Koko Seamount (∼ 48Ma) ................ 199 7.3.3 Platinum Group Elements and Re–Os Isotopes . 200 v 7.4 Discussion ............................... 204 7.4.1 Significance of Pd and Os Depletions . 205 7.4.2 PGEandRe–OsSystematics . 210 7.4.3 Effect of Sulfide Retention in the Source of the Hawaiian Plume ............................. 220 7.5 Conclusions .............................. 223 CHAPTER8:CONCLUSIONS . 226 8.1 TheOntongJavaPlateau . 226 8.2 Hawaiian Ridge-Emperor Seamount Chain . 228 8.3 Summary ............................... 231 8.4 RelevanceandFutureWork . 232 CHAPTER 9: ANALYTICAL TECHNIQUES . 234 9.1 OverviewofTechniques. 234 9.2 SamplePreparation. 234 9.3 LossonIgnition............................ 235 9.4 MajorElementAnalysis . 237 9.5 TraceElementAnalysis. 240 9.6 Platinum Group Element Analysis . 246 9.7 IsotopeAnalyses ........................... 248 9.7.1 Sr-, Nd-, & Pb-Isotope Analysis as part of Chapter 4 . 249 9.7.2 Sr- & Nd-Isotope Analysis as part of Chapter 6 . 250 9.7.3 OsIsotopeAnalyses . 252 BIBLIOGRAPHY ............................... 253 vi FIGURES 1.1 Map of the Ontong Java Plateau and surrounding area . 2 1.2 Map of the Hawaiian Ridge-Emperor Seamount Chain . 5 2.1 Map of the Ontong Java Plateau, highlighting the island of Malaita 12 87 86 2.2 Graph of Sr/ Sr vs. ǫNd for OJP basalts and MORB basalts . 13 2.3 Primitive mantle normalized profiles of basalts recovered from Site 803................................... 14 2.4 Map of the Ontong Java Plateau, highlighting the eastern salient andSite1184 ............................. 16 3.1 Schematic of a rising mantle plume . 20 3.2 Map of the Hawaiian Ridge-Emperor Seamount Chain . 25 3.3 Map of the Hawaiian Islands showing the Kea and Loa trends .. 28 3.4 208Pb/204Pb vs 176Hf/177Hf, 87Sr/86Sr, and 143Nd/144Nd isotopic ra- tios showing the distinct fields for Kea and Loa trend volcanoes . 29 3.5 MgO vs SiO2 forKilaueatholeiiticbasalts . 30 3.6 Incompatible element diagram of Kilauea shield
Load more

Recommended publications
  • Cenozoic Changes in Pacific Absolute Plate Motion A
    CENOZOIC CHANGES IN PACIFIC ABSOLUTE PLATE MOTION A THESIS SUBMITTED TO THE GRADUATE DIVISION OF THE UNIVERSITY OF HAWAI`I IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE IN GEOLOGY AND GEOPHYSICS DECEMBER 2003 By Nile Akel Kevis Sterling Thesis Committee: Paul Wessel, Chairperson Loren Kroenke Fred Duennebier We certify that we have read this thesis and that, in our opinion, it is satisfactory in scope and quality as a thesis for the degree of Master of Science in Geology and Geophysics. THESIS COMMITTEE Chairperson ii Abstract Using the polygonal finite rotation method (PFRM) in conjunction with the hotspot- ting technique, a model of Pacific absolute plate motion (APM) from 65 Ma to the present has been created. This model is based primarily on the Hawaiian-Emperor and Louisville hotspot trails but also incorporates the Cobb, Bowie, Kodiak, Foundation, Caroline, Mar- quesas and Pitcairn hotspot trails. Using this model, distinct changes in Pacific APM have been identified at 48, 27, 23, 18, 12 and 6 Ma. These changes are reflected as kinks in the linear trends of Pacific hotspot trails. The sense of motion and timing of a number of circum-Pacific tectonic events appear to be correlated with these changes in Pacific APM. With the model and discussion presented here it is suggested that Pacific hotpots are fixed with respect to one another and with respect to the mantle. If they are moving as some paleomagnetic results suggest, they must be moving coherently in response to large-scale mantle flow. iii List of Tables 4.1 Initial hotspot locations .
    [Show full text]
  • Lumina 4C M02 TRUJ3545 1
    Tall mountains created by tectonic uplift. Tall coastal mountains such as these in Glacier Bay National Park in southeastern Alaska have been uplifted by plate tectonic processes, creating a large amount of relief. Some of the uplifted rocks here have come from distant areas and include parts of the sea floor. M02_TRUJ3545_12_SE_C02.indd 38 16/12/15 3:49 AM 2 Before you begin reading this chapter, use the glossary at the end of this book to discover the meanings of any of the words in the word cloud Plate Tectonics above you don’t already know. and the Ocean Floor ach year at various locations around the globe, several thousand earthquakes Eand dozens of volcanic eruptions occur, both of which indicate how remarkably ESSENTIAL LEARNING CONCEPTS dynamic our planet is. These events have occurred throughout history, constantly At the end of this chapter, you should be able to: changing the surface of our planet, yet only a little over 50 years ago, most scientists believed the continents were stationary over geologic time. Since that time, a bold 2.1 Evaluate the evidence that supports new theory has been advanced that helps explain surface features and phenomena continental drift. on Earth, including: 2.2 Summarize the evidence that supports plate tectonics. • The worldwide locations of volcanoes, faults, earthquakes, and mountain building • Why mountains on Earth haven’t been eroded away 2.3 Discuss the origin and characteristics of features that occur at plate boundaries. • The origin of most landforms and ocean floor features 2.4 Show how plate tectonics can be used as a • How the continents and ocean floor formed and why they are different working model.
    [Show full text]
  • Indications of Hotspot Movement
    Indications of Hotspot Movement The prominent bend in the Hawaiian-Emperor hotspot chain has previously been attributed to a significant change in the motion of the Pacific plate. The magnitude of a shift in plate motion large enough to create the bend present in the Hawaiian-Emperor chain would likely be present in other deposits in the pacific, which due to recent mapping of magnetic anomalies has not been observed. This leads to the hypothesis that the Hawaiian hotspot as well as the Pacific plate may be in motion. “One approach to examine hotspot fixity is to determine the age and paleolatitude of volcanoes that form a given hotspot track. For the Hawaiian hotspot, the paleolatitudes of extinct volcanic edifices of the Emperor chain should match the present-day latitude of Hawaii (~19º N) if the hotspot has remained fixed with respect to Earth's spin axis. The most reliable indicators of paleolatitude are basaltic rocks, but enough time must be spanned by any section such that geomagnetic secular variation is sampled. Recovery of such samples requires ocean drilling technology, and only a few seamounts have been sampled to date. Paleomagnetic analyses of 81-million-year-old basalt recovered from Detroit Seamount (Site 884) yielded a paleolatitude of ~36° N (10) that is discordant with Hawaii. Data from ~61 million-year-old basalt (9) from Suiko Seamount define a paleolatitude of 27° N (11). These data suggest that the Emperor Seamounts record southward motion of the hotspot plume in the mantle (10).” The Ocean Drilling Program(ODP) tested several seamounts in the Hawaiian-Emperor chain for paleolatitude data.
    [Show full text]
  • Non-Hawaiian Lithostratigraphy of Louisville Seamounts and the Formation of High-Latitude Oceanic Islands and Guyots
    Non-Hawaiian lithostratigraphy of Louisville seamounts and the formation of high-latitude oceanic islands and guyots David M. Buchsa,⁎, Rebecca Williamsb, Shin-ichi Sanoc, V. Paul Wrightd a Cardiff University, UK b University of Hull, UK c Fukui Prefectural Dinosaur Museum, Japan d National Museum of Wales, UK This is an author accepted manuscript for an article published in Journal of Volcanology and Geothermal Research, doi: 10.1016/j.jvolgeores.2017.12.019. ABSTRACT Guyots are large seamounts with a flat summit that is generally believed to form due to constructional biogenic and/or erosional processes during the formation of volcanic islands. However, despite their large abundance in the oceans, there are still very few direct constraints on the nature and formation of guyots, in particular those formed at high latitude that lack a thick cap of shallow-marine carbonate rocks. It is largely accepted based on geophysical constraints and surficial observations/sampling that the summit platform of these guyots is shaped by wave abrasion during post-volcanic subsidence of volcanic islands. Here we provide novel constraints on this hypothesis and the summit geology of guyots with a lithostratigraphic analysis of cores from three Louisville seamounts (South Pacific) collected during Expedition 330 of the Integrated Ocean Drilling Program (IODP). Thirteen lithofacies of sedimentary and volcanic deposits are described, which include facies not previously recognized on the top of guyots, and offer a new insight into the formation of high-latitude oceanic islands on a fast- moving plate. Our results reveal that the lithostratigraphy of Louisville seamounts preserves a very consistent record of the formation and drowning of volcanic islands, with from bottom to top: (i) volcaniclastic sequences with abundant lava-fed delta deposits, (ii) submarine to subaerial shield lava flows, (iii) post-volcanic shallow to deeper marine sedimentary rocks lacking thick reef deposits, (iv) post-erosional rejuvenated volcanic rocks, and (v) pelagic sediments.
    [Show full text]
  • He Along the Hawaiian-Emperor Volcanic Chain
    Article Geochemistry 3 Volume 5,Number12 Geophysics 31 December 2004 Q12L05, doi:10.1029/2004GC000739 GeosystemsG G ISSN: 1525-2027 AN ELECTRONIC JOURNAL OF THE EARTH SCIENCES Published by AGU and the Geochemical Society Cretaceous-to-recent record of elevated 3He//4He along the Hawaiian-Emperor volcanic chain R. A. Keller and D. W. Graham College of Oceanic and Atmospheric Sciences, Oregon State University, Corvallis, Oregon 97331, USA ([email protected]) K. A. Farley Division of Geological and Planetary Sciences, MS 170-25, California Institute of Technology, Pasadena, California 91125, USA R. A. Duncan College of Oceanic and Atmospheric Sciences, Oregon State University, Corvallis, Oregon 97331, USA J. E. Lupton Pacific Marine Environmental Laboratory, National Oceanic and Atmospheric Administration, Hatfield Marine Science Center, Newport, Oregon 97365, USA [1] Helium isotopes are a robust geochemical tracer of a primordial mantle component in hot spot 3 4 3 4 À6 volcanism. The high He/ He (up to 35 RA, where RA is the atmospheric He/ He ratio of 1.39 Â 10 )of some Hawaiian Island volcanism is perhaps the classic example. New results for picrites and basalts from the Hawaiian-Emperor seamount chain indicate that the hot spot has produced high 3He/4He lavas for at 3 4 least the last 76 million years. Picrites erupted at 76 Ma have He/ He (10–14 RA), which is at the lower end of the range for the Hawaiian Islands but still above the range of modern mid-ocean ridge basalt (MORB; 6–10 RA). This was at a time when hot spot volcanism was occurring on thin lithosphere close to a spreading ridge and producing lava compositions otherwise nearly indistinguishable from MORB.
    [Show full text]
  • Heading Across the Pacific
    Our Ocean Backyard –– Santa Cruz Sentinel columns by Gary Griggs, Director, Institute of Marine Sciences, UC Santa Cruz. #149 January 11, 2014 Heading Across the Pacific Our ocean backyard is going to be a bit more global for the next four and a half months. We departed Friday, January 10 from Ensenada, Mexico on a 600-foot ship, the MV Explorer, headed for Hawaii. So this morning we will be about 200 miles further west as we head across the middle of the Pacific, hopefully with calm seas while we get acclimated to life on the water. I’m teaching on the Semester-at-Sea program, administered by the University of Virginia, and which has about 550 students from 280 different colleges and universities enrolled in a worldwide voyage of discovery. Our Spring 2014 voyage will be the 50th anniversary of the program, which will probably be cause for some occasional celebration along the way. Forty faculty members teach classes every day at sea, but while in port, educational, cultural, natural history and other field trips, travel and experiences will provide for a unique opportunity to study and learn about the global natural environment and also the diverse human communities. Over the next four months the ship will have port stops in 16 cities in 12 different countries, including Japan, China, Hong Kong, Viet Nam, Singapore, Myanmar, India, Mauritius, South Africa, Ghana, and Morocco. After having sailed about 25,000 miles across the Pacific, Indian and Atlantic Oceans, the ship will dock in Southampton, England on May 2nd. From my own past experiences on ships, I think it’s fair to say that after this many months at sea, most everybody on board will be happy to be on dry land and a stable platform again.
    [Show full text]
  • Constraints on Past Plate and Mantle Motion from New Ages for the Hawaiian-Emperor Seamount Chain
    Article Volume 14, Number 10 4 October 2013 doi: 10.1002/ggge.20267 ISSN: 1525-2027 Constraints on past plate and mantle motion from new ages for the Hawaiian-Emperor Seamount Chain John M. O’Connor Alfred Wegener Institute for Polar and Marine Research, Bremerhaven, Germany GeoZentrum Nordbayern, University Erlangen-Nuremberg, Erlangen, Germany Deep Earth and Planetary Sciences, VU University Amsterdam, De Boelelaan 1085, 1081 HVAmsterdam, Neth- erlands ([email protected]) Bernhard Steinberger Helmholtz Centre Potsdam—GFZ German Research Centre for Geosciences, Potsdam, Germany The Centre for Earth Evolution and Dynamics, University of Oslo, Oslo, Norway Marcel Regelous GeoZentrum Nordbayern, University Erlangen-Nuremberg, Erlangen, Germany Anthony A. P. Koppers CEOAS, Oregon State University, Corvallis, Oregon, USA Jan R. Wijbrans Deep Earth and Planetary Sciences, VU University Amsterdam, Amsterdam, Netherlands Karsten M. Haase GeoZentrum Nordbayern, University Erlangen-Nuremberg, Erlangen, Germany Peter Stoffers Institute for Geosciences, Christian-Albrechts-University, Kiel, Germany Wilfried Jokat Alfred Wegener Institute for Polar and Marine Research, Bremerhaven, Germany Dieter Garbe-Schönberg Institute for Geosciences, Christian-Albrechts-University, Kiel, Germany [1] Estimates of the relative motion between the Hawaiian and Louisville hot spots have consequences for understanding the role and character of deep Pacific-mantle return flow. The relative motion between these primary hot spots can be inferred by comparing the age records for their seamount trails. We report 40Ar/39Ar ages for 18 lavas from 10 seamounts along the Hawaiian-Emperor Seamount Chain (HESC), showing that volcanism started in the sharp portion of the Hawaiian-Emperor Bend (HEB) at 47.5 Ma and continued for 5 Myr.
    [Show full text]
  • Petrogenesis of Lavas from Detroit Seamount: Geochemical Differences Between Emperor Chain and Hawaiian Volcanoes
    Edinburgh Research Explorer Petrogenesis of lavas from Detroit Seamount: Geochemical differences between Emperor Chain and Hawaiian volcanoes Citation for published version: Huang, S, Regelous, M, Thordarson, T & Frey, FA 2005, 'Petrogenesis of lavas from Detroit Seamount: Geochemical differences between Emperor Chain and Hawaiian volcanoes', Geochemistry, Geophysics, Geosystems, vol. 6, no. 1, Q01L06, pp. 1-52. https://doi.org/10.1029/2004GC000756 Digital Object Identifier (DOI): 10.1029/2004GC000756 Link: Link to publication record in Edinburgh Research Explorer Document Version: Publisher's PDF, also known as Version of record Published In: Geochemistry, Geophysics, Geosystems Publisher Rights Statement: Published in Geochemistry, Geophysics, Geosystems by the American Geophysical Union (2005) General rights Copyright for the publications made accessible via the Edinburgh Research Explorer is retained by the author(s) and / or other copyright owners and it is a condition of accessing these publications that users recognise and abide by the legal requirements associated with these rights. Take down policy The University of Edinburgh has made every reasonable effort to ensure that Edinburgh Research Explorer content complies with UK legislation. If you believe that the public display of this file breaches copyright please contact [email protected] providing details, and we will remove access to the work immediately and investigate your claim. Download date: 06. Oct. 2021 Article Geochemistry 3 Volume 6, Number 1 Geophysics 28 January 2005 Q01L06, doi:10.1029/2004GC000756 GeosystemsG G ISSN: 1525-2027 AN ELECTRONIC JOURNAL OF THE EARTH SCIENCES Published by AGU and the Geochemical Society Petrogenesis of lavas from Detroit Seamount: Geochemical differences between Emperor Chain and Hawaiian volcanoes S.
    [Show full text]
  • A Plate Model for Jurassic to Recent Intraplate Volcanism in the Pacific Ocean Basin
    A Plate Model for Jurassic to Recent Intraplate Volcanism in the Pacific Ocean Basin Alan D. Smith Department of Geological Sciences, University of Durham, Durham, DH1 3LE, UK Email: [email protected] 1 ABSTRACT Reconstruction of the tectonic evolution of the Pacific basin indicates a direct relationship between intraplate volcanism and plate reorganisations, which suggests volcanism was controlled by fracturing and extension of the lithosphere. Middle Jurassic to Early Cretaceous intraplate volcanism included oceanic plateau formation at triple junctions (Shatsky Rise, western Mid Pacific Mountains) and a diffuse pattern of ocean island volcanism (Marcus Wake, Magellan seamounts) reflecting an absence of any well-defined stress field within the plate. The stress field changed in the Early Cretaceous when accretion of the Insular terrane to the North American Cordillera and the Median Tectonic arc to New Zealand, stalled migration of the Pacific- Farallon and Pacific-Phoenix ocean ridges, leading to the generation of the Ontong Java, Manahiki, Hikurangi and Hess Rise oceanic plateaus. Plate reorganisations in the Late Cretaceous resulted from the breakup of the Phoenix and Izanagi plates through collision of the Pacific-Phoenix ocean ridge with the southwest margin of the basin, and development of island arc-marginal basin systems in the northwest of the basin. The Pacific plate nonetheless remained largely bounded by spreading centres, and intraplate volcanism followed pre-existing lines of weakness in the plate fabric (Line Islands), or resulted from fractures generated by ocean ridge subduction beneath island arc systems (Emperor chain). The Pacific plate began to subduct under Asia in the Early Eocene from the record of accreted material along the Japanese margin.
    [Show full text]
  • He Along the Hawaiian-Emperor Volcanic Chain
    Article Geochemistry 3 Volume 5, Number 12 Geophysics 31 December 2004 GeosystemsG Q12L05, doi:10.1029/2004GC000739 G ISSN: 1525-2027 AN ELECTRONIC JOURNAL OF THE EARTH SCIENCES Published by AGU and the Geochemical Society Cretaceous-to-recent record of elevated 3He//4He along the Hawaiian-Emperor volcanic chain R. A. Keller and D. W. Graham College of Oceanic and Atmospheric Sciences, Oregon State University, Corvallis, Oregon 97331, USA ([email protected]) K. A. Farley Division of Geological and Planetary Sciences, MS 170-25, California Institute of Technology, Pasadena, California 91125, USA R. A. Duncan College of Oceanic and Atmospheric Sciences, Oregon State University, Corvallis, Oregon 97331, USA J. E. Lupton Pacific Marine Environmental Laboratory, National Oceanic and Atmospheric Administration, Hatfield Marine Science Center, Newport, Oregon 97365, USA [1] Helium isotopes are a robust geochemical tracer of a primordial mantle component in hot spot 3 4 3 4 À6 volcanism. The high He/ He (up to 35 RA, where RA is the atmospheric He/ He ratio of 1.39 Â 10 )of some Hawaiian Island volcanism is perhaps the classic example. New results for picrites and basalts from the Hawaiian-Emperor seamount chain indicate that the hot spot has produced high 3He/4He lavas for at 3 4 least the last 76 million years. Picrites erupted at 76 Ma have He/ He (10–14 RA), which is at the lower end of the range for the Hawaiian Islands but still above the range of modern mid-ocean ridge basalt (MORB; 6–10 RA). This was at a time when hot spot volcanism was occurring on thin lithosphere close to a spreading ridge and producing lava compositions otherwise nearly indistinguishable from MORB.
    [Show full text]
  • And 91-Av-19/4, Northwest Pacific and Bering Sea Sediment Geochemistry and Paleoceanographic Studies
    U.S. DEPARTMENT OF THE INTERIOR U.S. GEOLOGICAL SURVEY DATA AND RESULTS FROM R.V. ALEKSANDR VINOGRADOV CRUISES 91-AV-19/1, NORTH PACIFIC HYDROCHEMISTRY TRANSECT; 91-AV-19/2, NORTH EQUATORIAL PACIFIC KARIN RIDGE FE-MN CRUST STUDIES; AND 91-AV-19/4, NORTHWEST PACIFIC AND BERING SEA SEDIMENT GEOCHEMISTRY AND PALEOCEANOGRAPHIC STUDIES Edited by James R. Hein1, Alexander S. Bychkov2, and Ann E. Gibbs1 Open File Report 94-230 1994 This report is preliminary and has not been reviewed for conformity with the U.S. Geological Survey editorial standards or with the North American Stratigraphic Code. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. !U.S. Geological Survey, 345 Middlefield Rd., ms 999, Menlo Park, CA 94025-3591 ^Pacific Oceanological Institute, Far Eastern Branch Russian Academy of Sciences, 43 Baltiyskaya St., Vladivostok, 690041, Russia IN MEMORIAM: DR. MIKHAIL F. STASHCHUK We gratefully acknowledge the contributions of Dr. Mikhail F. Stashchuk, whose efforts made possible the Russian-U.S.A.-Canadian cooperative research program on which this report is based. Mikhail F. Stashchuk is a renowned Russian geologist and geochemist who passed away on March 5, 1991 at the age of 60. Mikhail headed the "Processes of Mineral Formation Laboratory" at the Pacific Oceanological Institute (POI), USSR Academy of Sciences, Vladivostok. This laboratory is involved in the study of ferromanganese crusts and nodules, phosphorites, the marine carbonate system, and other studies of marine geology and geochemistry. Mikhail is probably best known for his two books: "The Oxidation-Reduction Potential in Geology", which was first published in 1968 (Moscow, Nedra), but has been reprinted, translated, and published in the USA as well; and "Thermal Dynamics and its Application to Lithology", published in 1985, Moscow, Nauka.
    [Show full text]
  • Petrogenesis of Hawaiian Postshield Lavas: Evidence from Nintoku Seamount, Emperor Seamount Chain
    Article Geochemistry 3 Volume 6, Number 5 Geophysics 12 May 2005 Q05L09, doi:10.1029/2004GC000875 GeosystemsG G ISSN: 1525-2027 AN ELECTRONIC JOURNAL OF THE EARTH SCIENCES Published by AGU and the Geochemical Society Petrogenesis of Hawaiian postshield lavas: Evidence from Nintoku Seamount, Emperor Seamount Chain John T. Shafer and Clive R. Neal Department of Civil Engineering and Geological Science, University of Notre Dame, 156 Fitzpatrick Hall, Notre Dame, Indiana 46615, USA ( [email protected]) Marcel Regelous Department of Earth Sciences, University of Bristol, Bristol, UK Max Planck Institut fu¨r Chemie, Postfach 3060, Mainz 55020, Germany [1] We report major and trace element and Sr and Nd isotope data for a 283 m thick sequence of postshield lavas drilled during Ocean Drilling Project Leg 197 from Site 1205, Nintoku Seamount, an approximately 56 m.y. old volcano from the Emperor Seamount Chain. At least 25 subaerially erupted lava flow units were sampled, of which all but one are alkali basalts. Clasts of hawaiite and mugearite are present in a conglomerate overlying the basement sequence. Similar rock types characterize the postshield stage of many young Hawaiian volcanoes. Major and trace element, and age-corrected Sr and Nd isotope compositions of the Nintoku lavas are similar to those of young postshield lavas from the Hawaiian Islands. Concentrations of highly incompatible elements tend to increase, La/Yb and Nb/Zr ratios increase, and 87Sr/86Sr decreases with decreasing depth in the drill core. The more evolved rock types can be related to the underlying alkali basalts by fractional crystallization of olivine, clinopyroxene, plagioclase, and Fe- Ti oxides, all of which occur as phenocryst or significant groundmass phases in these lavas.
    [Show full text]