DOCSLIB.ORG

Provided for Non-Commercial Research and Educational Use. Not for Reproduction, Distribution Or Commercial Use

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Provided for Non-Commercial Research and Educational Use. Not for Reproduction, Distribution Or Commercial Use Provided for non-commercial research and educational use. Not for reproduction, distribution or commercial use. This article was originally published in the Treatise on Geophysics, published by Elsevier and the attached copy is provided by Elsevier for the author’s benefit and for the benefit of the author’s institution, for non-commercial research and educational use including use in instruction at your institution, posting on a secure network (not accessible to the public) within your institution, and providing a copy to your institution’s administrator. All other uses, reproduction and distribution, including without limitation commercial reprints, selling or licensing copies or access, or posting on open internet sites are prohibited. For exceptions, permission may be sought for such use through Elsevier’s permissions site at: http://www.elsevier.com/locate/permissionusematerial Information taken from the copyright line. The Editor-in-Chief is listed as Gerald Schubert and the imprint is Academic Press. Author's personal copy 7.09 Hot Spots and Melting Anomalies G. Ito, University of Hawaii, Honolulu, HI, USA P. E. van Keken, University of Michigan, Ann Arbor, MI, USA ª 2007 Elsevier B.V. All rights reserved. 7.09.1 Introduction 372 7.09.2 Characteristics 373 7.09.2.1 Volcano Chains and Age Progression 373 7.09.2.1.1 Long-lived age-progressive volcanism 373 7.09.2.1.2 Short-lived age-progressive volcanism 381 7.09.2.1.3 No age-progressive volcanism 382 7.09.2.1.4 Continental hot spots 383 7.09.2.1.5 The hot-spot reference frame 386 7.09.2.2 Topographic Swells 387 7.09.2.3 Flood Basalt Volcanism 388 7.09.2.3.1 Continental LIPs 388 7.09.2.3.2 LIPs near or on continental margins 389 7.09.2.3.3 Oceanic LIPs 391 7.09.2.3.4 Connections to hot spots 392 7.09.2.4 Geochemical Heterogeneity and Distinctions from MORB 393 7.09.2.5 Mantle Seismic Anomalies 393 7.09.2.5.1 Global seismic studies 393 7.09.2.5.2 Local seismic studies of major hot spots 395 7.09.2.6 Summary of Observations 399 7.09.3 Dynamical Mechanisms 400 7.09.3.1 Methods 400 7.09.3.2 Generating the Melt 401 7.09.3.2.1 Temperature 402 7.09.3.2.2 Composition 402 7.09.3.2.3 Mantle flow 404 7.09.3.3 Swells 405 7.09.3.3.1 Generating swells: Lubrication theory 405 7.09.3.3.2 Generating swells: Thermal upwellings and intraplate hot spots 407 7.09.3.3.3 Generating swells: Thermal upwellings and hot-spot–ridge interaction 408 7.09.3.4 Dynamics of Buoyant Upwellings 410 7.09.3.4.1 TBL instabilities 410 7.09.3.4.2 Thermochemical instabilities 411 7.09.3.4.3 Effects of variable mantle properties 412 7.09.3.4.4 Plume buoyancy flux and excess temperature 412 7.09.3.5 Chains, Age Progressions, and the Hot-spot Reference Frame 413 7.09.3.6 Large Igneous Provinces 414 7.09.3.7 Hot Spots: Modifications and Alternatives 417 7.09.3.7.1 Variable hot-spot durations from transient thermal plumes 417 7.09.3.7.2 Forming melting anomalies by upper-mantle processes 418 7.09.3.8 Geochemistry of Hotspots and Melting Anomalies Vs MORB 420 7.09.4 Conclusions and Outlook 421 References 422 371 Treatise on Geophysics, vol. 7, pp. 371-435 Author's personal copy 372 Hot Spots and Melting Anomalies Nomenclature Ra thermal Rayleigh number À2 g acceleration of gravity (m s ) Rac critical Rayleigh number h average swell height (m) T temperature (K) qp plume heat flux associated with swell Up, U plate speed, seafloor spreading rate buoyancy flux (m sÀ1) s hot-spot swell volume flux V volume (m3) t time (s) W average intraplate swell width (m), or steady-state ridge-axis swell depth (m) x horizontal dimension (m) W swell width (m) xr distance between plume source and W0 characteristic width scale (m) ridge axis (m) thermal expansivity (KÀ1) B buoyancy flux (kg sÀ1) thickness of boundary layer (m) C composition thermal diffusivity (m2 sÀ1) C1, C2, constants used in scaling of swell width characteristic growth time (s) C3 , viscosity (Pa s) E equation of an ellipse density (kg mÀ3) À3 F fraction partial melting c crustal density (kg m ) À3 H thickness of fluid m mantle density (kg m ) À3 L0 characteristic length scale (m) w density of sea water (kg m ) M volumetric rate of melt generation ÁT Temperature (contrast (K)) (m3 sÀ1) Á density difference between buoyant and P pressure (Pa) normal mantle (kg mÀ3) Q volume flux of buoyant material (m3 sÀ1) 7.09.1 Introduction that hot spots are generated by convective upwellings, or plumes of unusually hot, buoyant mantle, which rise The original work by Wilson (1963, 1973), Morgan from the lower mantle (Wilson, 1963, 1973; Morgan, (1971, 1972), and Crough (1978) established the concept 1971, 1972; Whitehead and Luther, 1975) possibly of ‘hot spot’ as a broad swelling of topography capped through a chemically stratified mantle (e.g., Richter by volcanism, which, combined with plate motion, gen- and McKenzie, 1981). The large mushroom-shaped erates volcanoes aligned in a chain and with ages that head of an initiating mantle plume and the trailing, progress monotonically. In some cases, these chains more narrow plume stem has become a popular expla- project back to massive volcanic plateaus, or large nationfortheformationofaLIPfollowedbyahot-spot igneous provinces (LIPs), suggesting that hot-spot track (e.g., Richards et al., 1989; Campbell and Griffiths, activity began with some of the largest magmatic out- 1990). bursts evident in the geologic record (Morgan, 1972; Studies of hot spots have flourished over the past Richards et al., 1989; Duncan and Richards, 1991). Hot- few decades. Recent articles and textbooks have spot volcanism is dominantly basaltic and therefore reviewed some of the classic connections between largely involves melting of mantle peridotite, a process hot spots and mantle plumes (e.g., Jackson, 1998; that also produces mid-oceanic ridge volcanism. Yet Davies, 1999; Condie, 2001; Schubert et al., 2001), the mid-ocean ridge basalts (MORBs) and hot-spot basalts role of mantle plumes in deep-mantle convection and typically have distinct radiogenic isotope characteristics chemical transport (Jellinek and Manga, 2004), and (Hart et al., 1973; Schilling, 1973). These differences oceanic hot spots (e.g., Ito et al., 2003; Hekinian et al., indicate that the two forms of magmatism come from 2004). Alternative mechanisms, which emphasize pro- mantle materials that have preserved distinct chemical cesses in the asthenosphere and lithosphere, are being identities for hundreds of millions of years. re-evaluated and some new ones proposed (Foulger The above characteristics suggest that hot-spot vol- et al., 2005). It has become clear that few hot spots canism has an origin that is at least partly decoupled confidently show all of the above characteristics of the from plate processes. A straightforward explanation is classicdescription.Thetermhotspotitselfimpliesa Treatise on Geophysics, vol. 7, pp. 371-435 Author's personal copy Hot Spots and Melting Anomalies 373 localized region of anomalously high mantle tempera- concept. As both chains terminate at subduction ture, but some features that were originally called hot zones, the existing volcanoes likely record only part of spots may involve mantle with little or no excess heat, the activities of these hot spots. The Gala´pagosisthe volcanoes spanning large distances of a chain with other Pacific hot spot with a similar duration. Its inter- similar ages, or both. Thus, the terms ‘magmatic action with the Gala´pagos Spreading Center has anomaly’ or ‘melting anomaly’ may be more general produced two chains: the Gala´pagos Archipelago– and appropriate to describe the topic of this chapter. Carnegie Ridge on the Nazca Plate (Sinton et al., Progress made in the last decade on studies of hot 1996) and the Cocos Ridge on the Cocos Plate. The spots and melting anomalies is emphasized here. We Cocos Ridge records oceanic volcanism for 14.5 My summarize the recent observations and discuss the (Werner et al., 1999) and projects toward the Caribbean major dynamical processes that have been explored LIP (Duncan and Hargraves, 1984), which has and evaluate their ability to explain the main char- 40Ar/39Ar dates of 69–139 Ma (e.g., Sinton et al., 1997; acteristics. Mechanisms involving hot mantle plumes Hoernle et al., 2004). The geochemical similarity of have seen the most extensive quantitative testing, but these lavas with the Gala´pagos Archipelago is compel- the recent observations compel the exploration and ling evidence for a 139MylifespanfortheGala´pagos rigorous testing of other mechanisms. We summarize hotspot(Hoernleet al., 2002, 2004). the main observations, outline mechanisms that have In the Indian Ocean, Mu¨ller et al.’s (1993b) com- been proposed, and pose questions that need quanti- pilation of ages associates the Re´union hot spot with tative answers. volcanism on the Mascarene Plateau at 45 Ma (Duncan et al., 1990), the Cocos–Laccadive Plateau 60 Ma (Duncan, 1978, 1991), and finally the Deccan 7.09.2 Characteristics flood basalts in India, which are dated at 65–66 Ma (see also Sheth (2005)). The Comoros hot spot can be Guided by the classical description of hot spots, we linked to volcanism around the Seychelles islands examine four main characteristics: (1) geographic dated at 63 Ma (Emerick and Duncan, 1982; Mu¨ller age progression along volcano chains, (2) initiation et al., 1993b). Volcanism associated with the Marion by massive flood basalt volcanism, (3) anomalously hot-spot projects from Marion island (<0.5 Ma shallow topography surrounding volcanoes (i.e., a (McDougall et al., 2001)) along a volcanic ridge to hot-spot swell), and (4) basaltic volcanism with geo- Madagascar.
Load more

Recommended publications
  • Geochemistry This
    TORONTOTORONTO Vol. 8, No. 4 April 1998 Call for Papers GSA TODAY — page C1 A Publication of the Geological Society of America Electronic Abstracts Submission — page C3 Antarctic Neogene Landscapes—In the 1998 Registration Refrigerator or in the Deep Freeze? Annual Issue Meeting — June GSA Today Introduction The present Molly F. Miller, Department of Geology, Box 117-B, Vanderbilt Antarctic landscape undergoes very University, Nashville, TN 37235, [email protected] slow environmental change because it is almost entirely covered by a thick, slow-moving ice sheet and thus effectively locked in a Mark C. G. Mabin, Department of Tropical Environmental Studies deep freeze. The ice sheet–landscape system is essentially stable, and Geography, James Cook University, Townsville, Queensland 4811, Australia, [email protected] Antarctic—Introduction continued on p. 2 Atmospheric Transport of Diatoms in the Antarctic Sirius Group: Pliocene Deep Freeze Arjen P. Stroeven, Department of Quaternary Research, Stockholm University, S-106 91 Stockholm, Sweden Lloyd H. Burckle, Lamont-Doherty Earth Observatory of Columbia University, Palisades, NY 10964 Johan Kleman, Department of Physical Geography, Stockholm University, S-106, 91 Stockholm, Sweden Michael L. Prentice, Institute for the Study of Earth, Oceans, and Space, University of New Hampshire, Durham, NH 03824 INTRODUCTION How did young diatoms (including some with ranges from the Pliocene to the Pleistocene) get into the Sirius Group on the slopes of the Transantarctic Mountains? Dynamicists argue for emplacement by a wet-based ice sheet that advanced across East Antarctica and the Transantarctic Mountains after flooding of interior basins by relatively warm marine waters [2 to 5 °C according to Webb and Harwood (1991)].
    [Show full text]
  • Copyrighted Material
    Index Page numbers in italics refer to fi gures; those in bold to tables Acasta gneisses 347 sea fl oor divided into 84 diversity of 288–9 accretionary orogens, structure 287, 309, Aleutian accretionary prism growth latest phase of compression 289 336–42 rate 267 Andean foreland, styles of tectonic active, seismic refl ection profi les 295, 315, Aleutian arc, focal mechanism solutions of shortening 292, 292, 293, 294 340, 342 earthquakes 256, 257 foreland basement thrusts 292, 293 Canadian Cordillera 336–7, 338, 339, 341, Aleutian–Alaska arc, prominent gap in segmentation of foreland 292, 294 376 seismicity 259, 261 thick-skinned and thin-skinned fold and common features of 338, 340, 502 alkaline series, includes shoshonitic thrust belts 292, 293 western North America 336, 337 lavas 271 Andean-type subduction, specifi c types of accretionary prisms 251, 264–9, 270 Alpine Fault, New Zealand 228–30, 338 deposit 417–18 accumulation of sediments including accommodation of oblique slip 244, 245, backarc environment, granite belts with olistostromes 267 246 tin and tungsten 417–18 creation of mélange 268 Breaksea Basin once continuous with stratabound copper sulfi des 417 décollement 264, 266 Dagg Basin 220, 221, 222 Andes, central 301–2 sliding on 267 central segment, weakly/non-partitioned arcuate shape (orocline) 294 deformation front 264 style of transpressional evolution of shortening (model) 300 development of 243, 244 deformation 213, 223 fl at and steep subduction zones 289, 291 and development of forearc basin 267 change in relative plate
    [Show full text]
  • And the Digital Data Files Contained on It (The “Content”), Is Governed by the Terms Set out on This Page (“Terms of Use”)
    ISBN 978-1-4249-9924-8 [DVD] ISBN 978-1-4249-9925-5[ZIP FILE] THESE TERMS GOVERN YOUR USE OF THIS PRODUCT Your use of this electronic information product (“EIP”), and the digital data files contained on it (the “Content”), is governed by the terms set out on this page (“Terms of Use”). By opening the EIP and viewing the Content , you (the “User”) have accepted, and have agreed to be bound by, the Terms of Use. EIP and Content: This EIP and Content is offered by the Province of Ontario’s Ministry of Northern Development and Mines (MNDM) as a public service, on an “as-is” basis. Recommendations and statements of opinions expressed are those of the author or authors and are not to be construed as statement of government policy. You are solely responsible for your use of the EIP and its Content. You should not rely on the Content for legal advice nor as authoritative in your particular circumstances. Users should verify the accuracy and applicability of any Content before acting on it. MNDM does not guarantee, or make any warranty express or implied, that the Content is current, accurate, complete or reliable or that the EIP is free from viruses or other harmful components. MNDM is not responsible for any damage however caused, which results, directly or indirectly, from your use of the EIP or the Content. MNDM assumes no legal liability or responsibility for the EIP or the Content whatsoever. Links to Other Web Sites: This EIP or the Content may contain links, to Web sites that are not operated by MNDM.
    [Show full text]
  • Synoptic Taxonomy of Major Fossil Groups
    APPENDIX Synoptic Taxonomy of Major Fossil Groups Important fossil taxa are listed down to the lowest practical taxonomic level; in most cases, this will be the ordinal or subordinallevel. Abbreviated stratigraphic units in parentheses (e.g., UCamb-Ree) indicate maximum range known for the group; units followed by question marks are isolated occurrences followed generally by an interval with no known representatives. Taxa with ranges to "Ree" are extant. Data are extracted principally from Harland et al. (1967), Moore et al. (1956 et seq.), Sepkoski (1982), Romer (1966), Colbert (1980), Moy-Thomas and Miles (1971), Taylor (1981), and Brasier (1980). KINGDOM MONERA Class Ciliata (cont.) Order Spirotrichia (Tintinnida) (UOrd-Rec) DIVISION CYANOPHYTA ?Class [mertae sedis Order Chitinozoa (Proterozoic?, LOrd-UDev) Class Cyanophyceae Class Actinopoda Order Chroococcales (Archean-Rec) Subclass Radiolaria Order Nostocales (Archean-Ree) Order Polycystina Order Spongiostromales (Archean-Ree) Suborder Spumellaria (MCamb-Rec) Order Stigonematales (LDev-Rec) Suborder Nasselaria (Dev-Ree) Three minor orders KINGDOM ANIMALIA KINGDOM PROTISTA PHYLUM PORIFERA PHYLUM PROTOZOA Class Hexactinellida Order Amphidiscophora (Miss-Ree) Class Rhizopodea Order Hexactinosida (MTrias-Rec) Order Foraminiferida* Order Lyssacinosida (LCamb-Rec) Suborder Allogromiina (UCamb-Ree) Order Lychniscosida (UTrias-Rec) Suborder Textulariina (LCamb-Ree) Class Demospongia Suborder Fusulinina (Ord-Perm) Order Monaxonida (MCamb-Ree) Suborder Miliolina (Sil-Ree) Order Lithistida
    [Show full text]
  • Giant Radiating Mafic Dyke Swarm of the Emeishan Large Igneous Province: Identifying the Mantle Plume Centre
    doi: 10.1111/ter.12154 Giant radiating mafic dyke swarm of the Emeishan Large Igneous Province: Identifying the mantle plume centre Hongbo Li,1,2 Zhaochong Zhang,1 Richard Ernst,3,4 Linsu L€u,2 M. Santosh,1 Dongyang Zhang1 and Zhiguo Cheng1 1State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences, Beijing 100083, China; 2Geologi- cal Museum of China, Beijing 100034, China; 3Department of Earth Sciences, Carleton University, Ottawa, ON K1S 5B6, Canada; 4Ernst Geosciences, 43 Margrave Avenue, Ottawa, ON K1T 3Y2, Canada ABSTRACT In many continental large igneous provinces, giant radiating and recognized six dyke sub-swarms, forming an overall dyke swarms are typically interpreted to result from the arri- radiating dyke swarm and converging in the Yongren area, val of a mantle plume at the base of the lithosphere. Mafic Yunnan province. This location coincides with the maximum dyke swarms in the Emeishan large igneous province (ELIP) pre-eruptive domal uplift, and is close to the locations of have not received much attention prior to this study. We high-temperature picrites. Our study suggests that the Yon- show that the geochemical characteristics and geochronologi- gren area may represent the mantle plume centre during the cal data of the mafic dykes are broadly similar to those of peak of Emeishan magmatism. the spatially associated lavas, suggesting they were derived from a common parental magma. Based on the regional geo- Terra Nova, 27, 247–257, 2015 logical data and our field observations, we mapped the spa- tial distribution patterns of mafic dyke swarms in the ELIP, ridge by a continent (Gower and swarms and their distributions pro- Introduction Krogh, 2002), edge-driven enhanced vide an opportunity to further test Large igneous provinces (LIPs) are mantle convection (King and Ander- the plume model for the ELIP.
    [Show full text]
  • Instability of the Southern Canadian Shield During the Late Proterozoic 2 3 Kalin T
    1 Instability of the southern Canadian Shield during the late Proterozoic 2 3 Kalin T. McDannella,b*, Peter K. Zeitlera, and David A. Schneiderc 4 5 aDepartment of Earth and Environmental Sciences, Lehigh University, 1 W. Packer Ave. Bethlehem PA, 18015 USA 6 7 bGeological Survey of Canada, Natural Resources Canada, 3303 – 33 St NW Calgary AB, T2L 2A7 Canada 8 9 cDepartment of Earth & Environmental Sciences, University of Ottawa, 25 Templeton Ave., Ottawa ON, K1N 6N5 10 Canada 11 12 *corresponding author: [email protected]; [email protected] 13 14 ABSTRACT 15 Cratons are generally considered to comprise lithosphere that has remained tectonically 16 quiescent for billions of years. Direct evidence for stability is mainly founded in the Phanerozoic 17 sedimentary record and low-temperature thermochronology, but for extensive parts of Canada, 18 earlier stability has been inferred due to the lack of an extensive rock record in both time and 19 space. We used 40Ar/39Ar multi-diffusion domain (MDD) analysis of K-feldspar to constrain 20 cratonic thermal histories across an intermediate (~150-350°C) temperature range in an attempt 21 to link published high-temperature geochronology that resolves the timing of orogenesis and 22 metamorphism with lower-temperature data suited for upper-crustal burial and unroofing 23 histories. This work is focused on understanding the transition from Archean-Paleoproterozoic 24 crustal growth to later intervals of stability, and how uninterrupted that record is throughout 25 Earth’s Proterozoic “Middle Age.” Intermediate-temperature thermal histories of cratonic rocks 26 at well-constrained localities within the southern Canadian Shield of North America challenge 27 the stability worldview because our data indicate that these rocks were at elevated temperatures 28 in the Proterozoic.
    [Show full text]
  • 7.09 Hot Spots and Melting Anomalies G
    7.09 Hot Spots and Melting Anomalies G. Ito, University of Hawaii, Honolulu, HI, USA P. E. van Keken, University of Michigan, Ann Arbor, MI, USA ª 2007 Elsevier B.V. All rights reserved. 7.09.1 Introduction 372 7.09.2 Characteristics 373 7.09.2.1 Volcano Chains and Age Progression 373 7.09.2.1.1 Long-lived age-progressive volcanism 373 7.09.2.1.2 Short-lived age-progressive volcanism 381 7.09.2.1.3 No age-progressive volcanism 382 7.09.2.1.4 Continental hot spots 383 7.09.2.1.5 The hot-spot reference frame 386 7.09.2.2 Topographic Swells 387 7.09.2.3 Flood Basalt Volcanism 388 7.09.2.3.1 Continental LIPs 388 7.09.2.3.2 LIPs near or on continental margins 389 7.09.2.3.3 Oceanic LIPs 391 7.09.2.3.4 Connections to hot spots 392 7.09.2.4 Geochemical Heterogeneity and Distinctions from MORB 393 7.09.2.5 Mantle Seismic Anomalies 393 7.09.2.5.1 Global seismic studies 393 7.09.2.5.2 Local seismic studies of major hot spots 395 7.09.2.6 Summary of Observations 399 7.09.3 Dynamical Mechanisms 400 7.09.3.1 Methods 400 7.09.3.2 Generating the Melt 401 7.09.3.2.1 Temperature 402 7.09.3.2.2 Composition 402 7.09.3.2.3 Mantle flow 404 7.09.3.3 Swells 405 7.09.3.3.1 Generating swells: Lubrication theory 405 7.09.3.3.2 Generating swells: Thermal upwellings and intraplate hot spots 407 7.09.3.3.3 Generating swells: Thermal upwellings and hot-spot–ridge interaction 408 7.09.3.4 Dynamics of Buoyant Upwellings 410 7.09.3.4.1 TBL instabilities 410 7.09.3.4.2 Thermochemical instabilities 411 7.09.3.4.3 Effects of variable mantle properties 412 7.09.3.4.4 Plume
    [Show full text]
  • EPSC 233: Earth and Life History
    EPSC 233: Earth and Life History Galen Halverson Fall Semester, 2014 Contents 1 Introduction to Geology and the Earth System 1 1.1 The Science of Historical Geology . 1 1.2 The Earth System . 4 2 Minerals and Rocks: The Building Blocks of Earth 6 2.1 Introduction . 6 2.2 Structure of the Earth . 6 2.3 Elements and Isotopes . 7 2.4 Minerals . 9 2.5 Rocks . 10 3 Plate Tectonics 16 3.1 Introduction . 16 3.2 Continental Drift . 16 3.3 The Plate Tectonic Revolution . 17 3.4 An overview of plate tectonics . 20 3.5 Vertical Motions in the Mantle . 24 4 Geological Time and the Age of the Earth 25 4.1 Introduction . 25 4.2 Relative Ages . 25 4.3 Absolute Ages . 26 4.4 Radioactive dating . 28 4.5 Other Chronostratigraphic Techniques . 31 5 The Stratigraphic Record and Sedimentary Environments 35 5.1 Introduction . 35 5.2 Stratigraphy . 35 5.3 Describing and interpreting detrital sedimentary rocks . 36 6 Life, Fossils, and Evolution 41 6.1 Introduction . 41 6.2 Fossils . 42 6.3 Biostratigraphy . 44 6.4 The Geological Time Scale . 45 6.5 Systematics and Taxonomy . 46 6.6 Evolution . 49 6.7 Gradualism Versus Punctuated Equilibrium . 53 i ii 7 The Environment and Chemical Cycles 55 7.1 Introduction . 55 7.2 Ecology . 56 7.3 The Atmosphere . 57 7.4 The Terrestrial Realm . 61 7.5 The Marine Realm . 63 8 Origin of the Earth and the Hadean 66 8.1 Introduction . 66 8.2 Origin of the Solar System .
    [Show full text]
  • Flow Fabric Determination of Two Mesoproterozoic Midcontinent Rift Dike Swarms, Northeastern Minnesota
    FLOW FABRIC DETERMINATION OF TWO MESOPROTEROZOIC MIDCONTINENT RIFT DIKE SWARMS, NORTHEASTERN MINNESOTA A thesis submitted to the Kent State University Graduate College in partial fulfillment of the requirements for the degree of Master of Science by Elizabeth May Fein May, 2009 Thesis written by Elizabeth May Fein B.A., Oberlin College, 2003 M.S., Kent State University, 2009 Approved by ___________________________________, Advisor Daniel Holm ___________________________________, Chair, Department of Geology Daniel Holm ___________________________________, Dean, College of Arts and Sciences Timothy Moerland ii DEPARTMENT OF GEOLOGY THESIS APPROVAL FORM This thesis, entitled Flow fabric determination of two Mesoproterozoic midcontinent rift dike swarms, northeastern Minnesota has been submitted by Elizabeth Fein in partial fulfillment of the requirements for the Master of Science in Geology. The undersigned member’s of the student’s thesis committee have read this thesis and indicated their approval or disapproval of the same. Approval Date Disapproval Date _______________________________ _______________________________ Daniel Holm Daniel Holm _______________________________ _______________________________ Donald Palmer Donald Palmer _______________________________ _______________________________ David Schneider David Schneider iii Table of Contents List of Figures…………………………………………………………………………....v List of Tables…………………………………………………………………………….vi Acknowledgements…………………………………………………………………….vii Abstract ………………………………………………………………………………….1 1. Introduction
    [Show full text]
  • Stratiform Chromite Deposit Model
    Stratiform Chromite Deposit Model Chapter E of Mineral Deposit Models for Resource Assessment Scientific Investigations Report 2010–5070–E U.S. Department of the Interior U.S. Geological Survey COVER: Photograph showing outcropping of the Bushveld LG6 chromitite seam. Photograph courtesy of Klaus J. Schulz, U.S. Geological Survey. Stratiform Chromite Deposit Model By Ruth F. Schulte, Ryan D. Taylor, Nadine M. Piatak, and Robert R. Seal II Chapter E of Mineral Deposit Model for Resource Assessment Scientific Investigations Report 2010–5070–E U.S. Department of the Interior U.S. Geological Survey U.S. Department of the Interior KEN SALAZAR, Secretary U.S. Geological Survey Marcia K. McNutt, Director U.S. Geological Survey, Reston, Virginia: 2012 For more information on the USGS—the Federal source for science about the Earth, its natural and living resources, natural hazards, and the environment, visit http://www.usgs.gov or call 1–888–ASK–USGS. For an overview of USGS information products, including maps, imagery, and publications, visit http://www.usgs.gov/pubprod To order this and other USGS information products, visit http://store.usgs.gov Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Although this report is in the public domain, permission must be secured from the individual copyright owners to reproduce any copyrighted materials contained within this report. Suggested citation: Schulte, R.F., Taylor, R.D., Piatak, N.M., and Seal, R.R., II, 2012, Stratiform chromite deposit model, chap. E of Mineral deposit models for resource assessment: U.S.
    [Show full text]
  • Implications of the Temporal Distribution of High‐Mg Magmas for Mantle Plume Volcanism Through Time Author(S): Ann E
    Implications of the Temporal Distribution of High‐Mg Magmas for Mantle Plume Volcanism through Time Author(s): Ann E. Isley and Dallas H. Abbott Source: The Journal of Geology, Vol. 110, No. 2 (March 2002), pp. 141-158 Published by: University of Chicago Press Stable URL: http://www.jstor.org/stable/10.1086/338553 Accessed: 22-01-2016 15:05 UTC Your use of the JSTOR archive indicates your acceptance of the Terms & Conditions of Use, available at http://www.jstor.org/page/ info/about/policies/terms.jsp JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact [email protected]. University of Chicago Press is collaborating with JSTOR to digitize, preserve and extend access to The Journal of Geology. http://www.jstor.org This content downloaded from 129.236.224.227 on Fri, 22 Jan 2016 15:05:16 UTC All use subject to JSTOR Terms and Conditions Implications of the Temporal Distribution of High-Mg Magmas for Mantle Plume Volcanism through Time Ann E. Isley and Dallas H. Abbott1 Department of Earth Sciences, Oswego State University of New York, Oswego, New York 13126, U.S.A. (e-mail: [email protected]) ABSTRACT We compile a 3.7-b.yr.-long time series of ultramafic and mafic rocks including extrusives and shallow intrusives (dikes and sills). We infer that peaks in the time series represent mantle plume events.
    [Show full text]
  • Paleomagnetic Evidence for a Large Rotation of the Yukon Block Relative to Laurentia: Implications for a Low-Latitude Sturtian Glaciation and the Breakup of Rodinia
    Paleomagnetic evidence for a large Yukon block rotation relative to Laurentia Paleomagnetic evidence for a large rotation of the Yukon block relative to Laurentia: Implications for a low-latitude Sturtian glaciation and the breakup of Rodinia Athena E. Eyster1,†, Roger R. Fu2, Justin V. Strauss3, Benjamin P. Weiss2, Charlie F. Roots4,§, Galen P. Halverson5, David A.D. Evans6, and Francis A. Macdonald1 1Department of Earth and Planetary Sciences, Harvard University, 20 Oxford Street, Cambridge, Massachusetts 02138, USA 2Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Building 54-724, Cambridge, Massachusetts 02139, USA 3Department of Earth Sciences, Dartmouth College, HB6105 Fairchild Hall, Hanover, New Hampshire 03755, USA 4Natural Resources Canada, c/o Box 2703, K-102, Whitehorse, Yukon Y1A 2C6, Canada 5Department of Earth and Planetary Sciences, McGill University, 3450 University Street, Montréal, Québec H3A0E8, Canada 6Department of Geology and Geophysics, Yale University, New Haven, Connecticut 06520, USA ABSTRACT in Mesoproterozoic and Paleoproterozoic Alternatively, Turner and Long (2008) argued strata, and realigns the orientation of the ca. for NE-SW extension on the western margin of Understanding the tectonic history of the 1260 Ma Bear River dikes with the Mack- Laurentia based on the interpretation of multi- supercontinent Rodinia is crucial for testing enzie dike swarm of northern Canada. This ple NE-SW–oriented structures in the Macken- proposed links among Neoproterozoic tec- reconstruction also facilitates future studies zie Mountains as transfer faults. In addition to tonics, supercontinent cycles, climate, and that relate Neoproterozoic sedimentary and these older structures, which can be interpreted biogeochemistry. The Neoproterozoic Mount structural patterns to the fragmentation of as recording early Neoproterozoic rifting, late Harper volcanics of the Ogilvie Mountains, Rodinia.
    [Show full text]