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Mantle and Geological Evidence for a Late Jurassic–Cretaceous Suture
Mantle and geological evidence for a Late Jurassic–Cretaceous suture spanning North America Mantle and geological evidence for a Late Jurassic–Cretaceous suture spanning North America Karin Sigloch1,† and Mitchell G. Mihalynuk2 1Department of Earth Sciences, University of Oxford, South Parks Road, Oxford OX1 3AN, UK 2British Columbia Geological Survey, P.O. Box Stn Prov Govt, Victoria, BC, V8W 9N3, Canada ABSTRACT of the archipelago, whereas North America ambient mantle, and seismic waves propagate converged on the archipelago by westward through it at slightly faster velocities. Joint sam- Crustal blocks accreted to North America subduction of an intervening, major ocean, pling of the subsurface by thousands to millions form two major belts that are separated by the Mezcalera-Angayucham Ocean. of crossing wave paths, generated by hundreds a tract of collapsed Jurassic–Cretaceous The most conspicuous geologic prediction or thousands of earthquakes, enables computa- basins extending from Alaska to Mexico. is that of an oceanic suture that must run tion of three-dimensional (3-D) tomographic Evidence of oceanic lithosphere that once along the entire western margin of North images of the whole-mantle structure. Some underlay these basins is rare at Earth’s sur- America. It formed diachronously between high-velocity domains connect upward to active face. Most of the lithosphere was subducted, ca. 155 Ma and ca. 50 Ma, analogous to subduction zones, providing a direct verification which accounts for the general difficulty of diachro nous suturing of southwest Pacific arcs of slab origin as cold, dense, and seismically fast reconstructing oceanic regions from sur- to the northward-migrating Australian conti- oceanic lithosphere (e.g., for North America, face evidence. -
Brief Communication: the Role of Geophysical Imaging in Local Landslide Early Warning Systems
https://doi.org/10.5194/nhess-2021-225 Preprint. Discussion started: 29 July 2021 c Author(s) 2021. CC BY 4.0 License. Brief communication: The role of geophysical imaging in local landslide early warning systems 1 2 1 3 1 Jim S. Whiteley , , Arnaud Watlet , J. Michael Kendall , Jonathan E. Chambers 1Shallow Geohazards and Earth Observation, British Geological Survey, Environmental Science Centre, Nicker Hill, 5 Nottingham, NG12 5GG, United Kingdom. 2School of Earth Sciences, University of Bristol, Wills Memorial Building, Queens Road, Bristol, BS8 1RJ, United Kingdom. 3University of Oxford, Department of Earth Sciences, South Parks Road, Oxford, OX1 3AN, United Kingdom Correspondence to: J.S. Whiteley ([email protected]) Abstract. We summarise the contribution of geophysical imaging to local landslide early warning systems (LoLEWS), 10 highlighting how LoLEWS design and monitoring components benefit from the enhanced spatial and temporal resolutions of time-lapse geophysical imaging. In addition, we discuss how with appropriate laboratory-based petrophysical transforms, these geophysical data can be crucial for future slope failure forecasting and modelling, linking other methods of remote sensing and intrusive monitoring across different scales. We conclude that in light of ever increasing spatiotemporal resolutions of data acquisition, geophysical monitoring should be a more widely considered technology in the toolbox of methods available to 15 stakeholders operating LoLEWS. 1 Introduction Landslide mitigation measures are broadly divided in to two types: engineering approaches to reduce frequency or intensity of failures; and vulnerability reduction measures that de-risk exposed elements (Pecoraro et al., 2019). Here we concentrate on the latter, through the use of landslide early warning systems (LEWS). -
Glacial Rebound and Plate Spreading: Results from the First Countrywide GPS Observations in Iceland
Geophys. J. Int. (2009) 177, 691–716 doi: 10.1111/j.1365-246X.2008.04059.x Glacial rebound and plate spreading: results from the first countrywide GPS observations in Iceland ∗ T. Arnad´ ottir,´ 1 B. Lund,2 W. Jiang,1 H. Geirsson,3 H. Bjornsson,¨ 4 P. Einarsson4 and T. Sigurdsson5 1Nordic Volcanological Center, Institute of Earth Sciences, University of Iceland, IS-101 Reykjav´ık, Iceland. E-mail: [email protected] 2Department of Earth Sciences, Uppsala University, Villavagen¨ 16, 752 36 Uppsala, Sweden 3Physics Department, Icelandic Meteorological Office, Reykjav´ık, Iceland 4Institute of Earth Sciences, University of Iceland, IS-101 Reykjav´ık, Iceland 5National Land Survey of Iceland, Akranes, Iceland Downloaded from https://academic.oup.com/gji/article/177/2/691/2023257 by guest on 30 September 2021 Accepted 2008 December 10. Received 2008 December 5; in original form 2008 June 12 SUMMARY Iceland is one of the few places on Earth where a divergent plate boundary can be observed on land. Direct observations of crustal deformation for the whole country are available for the first time from nationwide Global Positioning System (GPS) campaigns in 1993 and 2004. The plate spreading across the island is imaged by the horizontal velocity field and high uplift rates (≥10 mm yr−1) are observed over a large part of central and southeastern Iceland. Several earthquakes, volcanic intrusions and eruptions occurred during the time spanned by the measurements, causing local disturbances of the deformation field. After correcting for the largest earthquakes during the observation period, we calculate the strain rate field and find that the main feature of the field is the extension across the rift zones, subparallel to the direction of plate motion. -
Iceland Is Cool: an Origin for the Iceland Volcanic Province in the Remelting of Subducted Iapetus Slabs at Normal Mantle Temperatures
Iceland is cool: An origin for the Iceland volcanic province in the remelting of subducted Iapetus slabs at normal mantle temperatures G. R. Foulger§1 & Don L. Anderson¶ §Department of Geological Sciences, University of Durham, Science Laboratories, South Rd., Durham, DH1 3LE, U.K. ¶California Institute of Technology, Seismological Laboratory, MC 252-21, Pasadena, CA 91125, U. S. A. Abstract The time-progressive volcanic track, high temperatures, and lower-mantle seismic anomaly predicted by the plume hypothesis are not observed in the Iceland region. A model that fits the observations better attributes the enhanced magmatism there to the extraction of melt from a region of upper mantle that is at relatively normal temperature but more fertile than average. The source of this fertility is subducted Iapetus oceanic crust trapped in the Caledonian suture where it is crossed by the mid-Atlantic ridge. The extraction of enhanced volumes of melt at this locality on the spreading ridge has built a zone of unusually thick crust that traverses the whole north Atlantic. Trace amounts of partial melt throughout the upper mantle are a consequence of the more fusible petrology and can explain the seismic anomaly beneath Iceland and the north Atlantic without the need to appeal to very high temperatures. The Iceland region has persistently been characterised by complex jigsaw tectonics involving migrating spreading ridges, microplates, oblique spreading and local variations in the spreading direction. This may result from residual structural complexities in the region, inherited from the Caledonian suture, coupled with the influence of the very thick crust that must rift in order to accommodate spreading-ridge extension. -
Geophysical Imaging of Permafrost in the SW Svalbard – the Result of Two High Arctic Expeditions to Spitsbergen
EGU2020-8136, updated on 25 Sep 2021 https://doi.org/10.5194/egusphere-egu2020-8136 EGU General Assembly 2020 © Author(s) 2021. This work is distributed under the Creative Commons Attribution 4.0 License. Geophysical imaging of permafrost in the SW Svalbard – the result of two high arctic expeditions to Spitsbergen Mariusz Majdanski1, Artur Marciniak1, Bartosz Owoc1, Wojciech Dobiński2, Tomasz Wawrzyniak1, Marzena Osuch1, Adam Nawrot1, and Michał Glazer2 1Institute of Geophysics, Polish Academy of Sciences, Warsaw, Poland ([email protected]) 2Department of Earth Sciences, University of Silesia, Sosnowiec, Poland The Arctic regions are the place of the fastest observed climate change. One of the indicators of such evolution are changes occurring in the glaciers and the subsurface in the permafrost. The active layer of the permafrost as the shallowest one is well measured by multiple geophysical techniques and in-situ measurements. Two high arctic expeditions have been organized to use seismic methods to recognize the shape of the permafrost in two seasons: with the unfrozen ground (October 2017) and frozen ground (April 2018). Two seismic profiles have been designed to visualize the shape of permafrost between the sea coast and the slope of the mountain, and at the front of a retreating glacier. For measurements, a stand-alone seismic stations has been used with accelerated weight drop with in- house modifications and timing system. Seismic profiles were acquired in a time-lapse manner and were supported with GPR and ERT measurements, and continuous temperature monitoring in shallow boreholes. Joint interpretation of seismic and auxiliary data using Multichannel analysis of surface waves, First arrival travel-time tomography and Reflection imaging show clear seasonal changes affecting the active layer where P-wave velocities are changing from 3500 to 5200 m/s. -
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. -
Anomalous Late Jurassic Motion of the Pacific Plate With
View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Columbia University Academic Commons Earth and Planetary Science Letters 490 (2018) 20–30 Contents lists available at ScienceDirect Earth and Planetary Science Letters www.elsevier.com/locate/epsl Anomalous Late Jurassic motion of the Pacific Plate with implications for true polar wander a,b, a,c Roger R. Fu ∗, Dennis V. Kent a Lamont–Doherty Earth Observatory, Columbia University, Paleomagnetics Laboratory, 61 Route 9W, Palisades, NY 10964, USA b Department of Earth and Planetary Sciences, Harvard University, 20 Oxford St., Cambridge, MA 02138, USA c Department of Earth and Planetary Science, Rutgers University, 610 Taylor Rd, Piscataway, NY 08854, USA a r t i c l e i n f o a b s t r a c t Article history: True polar wander, or TPW, is the rotation of the entire mantle–crust system about an equatorial axis that Received 25 May 2017 results in a coherent velocity contribution for all lithospheric plates. One of the most recent candidate Received in revised form 19 February 2018 TPW events consists of a 30◦ rotation during Late Jurassic time (160–145 Ma). However, existing Accepted 25 February 2018 ∼ paleomagnetic documentation of this event derives exclusively from continents, which compose less Available online xxxx than 50% of the Earth’s surface area and may not reflect motion of the entire mantle–crust system. Editor: B. Buffett Additional paleopositional information from the Pacific Basin would significantly enhance coverage of the Keywords: Earth’s surface and allow more rigorous testing for the occurrence of TPW. -
The Commonwealth Trans-Antarctic Expedition 1955-1958
THE COMMONWEALTH TRANS-ANTARCTIC EXPEDITION 1955-1958 HOW THE CROSSING OF ANTARCTICA MOVED NEW ZEALAND TO RECOGNISE ITS ANTARCTIC HERITAGE AND TAKE AN EQUAL PLACE AMONG ANTARCTIC NATIONS A thesis submitted in fulfilment of the requirements for the Degree PhD - Doctor of Philosophy (Antarctic Studies – History) University of Canterbury Gateway Antarctica Stephen Walter Hicks 2015 Statement of Authority & Originality I certify that the work in this thesis has not been previously submitted for a degree nor has it been submitted as part of requirements for a degree except as fully acknowledged within the text. I also certify that the thesis has been written by me. Any help that I have received in my research and the preparation of the thesis itself has been acknowledged. In addition, I certify that all information sources and literature used are indicated in the thesis. Elements of material covered in Chapter 4 and 5 have been published in: Electronic version: Stephen Hicks, Bryan Storey, Philippa Mein-Smith, ‘Against All Odds: the birth of the Commonwealth Trans-Antarctic Expedition, 1955-1958’, Polar Record, Volume00,(0), pp.1-12, (2011), Cambridge University Press, 2011. Print version: Stephen Hicks, Bryan Storey, Philippa Mein-Smith, ‘Against All Odds: the birth of the Commonwealth Trans-Antarctic Expedition, 1955-1958’, Polar Record, Volume 49, Issue 1, pp. 50-61, Cambridge University Press, 2013 Signature of Candidate ________________________________ Table of Contents Foreword .................................................................................................................................. -
Plate Tectonics Review from Valerie Nulisch Some Questions (C) 2017 by TEKS Resource System
Plate Tectonics Review from Valerie Nulisch Some questions (c) 2017 by TEKS Resource System. Some questions (c) 2017 by Region 10 Educational Service Center. Some questions (c) 2017 by Progress Testing. Page 2 GO ON A student wanted to make a model of the Earth. The student decided to cut a giant Styrofoam ball in half and paint the layers on it to show their thickness. 1 Which model below best represents the layers of the Earth? A B C D Page 3 GO ON 2 A student is building a model of the layers of the Earth. Which material would best represent the crust? F Grouping of magnetic balls G Styrofoam packing pellets H Bag of shredded paper J Thin layer of graham crackers 3 Your teacher has asked you to make a model of the interior of the Earth. In your model, how do the thicknesses of the lithosphere and crust compare? A The lithosphere is thinner than the crust. B The lithosphere is exactly the same thickness as the crust. C The lithosphere is thicker than the crust. D The lithosphere is thicker than the oceanic crust, but thinner than the continental crust. 4 Sequence the layers of the Earth in order from the exterior surface to the interior center. F Lithosphere, mantle, inner core, outer core, crust, asthenosphere G Inner core, outer core, mantle, asthenosphere, lithosphere, crust H Crust, mantle, outer core, inner core, asthenosphere, lithosphere J Crust, lithosphere, asthenosphere, mantle, outer core, inner core Page 4 GO ON 5 The tectonic plate labeled A in the diagram is the A Eurasian Plate B Indo-Australian Plate C Pacific Plate D African Plate Page 5 GO ON 6 The tectonic plate labeled B in the diagram is the — F Eurasian Plate G Indo-Australian Plate H Pacific Plate J North American Plate Page 6 GO ON Directions: The map below shows Earth's tectonic plates; six of them are numbered. -
Time-Lapse Seismic and Electrical Monitoring of the Vadose Zone During a Controlled Infiltration Experiment at the Ploemeur Hydrological Observatory, France
water Article Time-Lapse Seismic and Electrical Monitoring of the Vadose Zone during a Controlled Infiltration Experiment at the Ploemeur Hydrological Observatory, France Lara A. Blazevic 1,2,*, Ludovic Bodet 2, Sylvain Pasquet 3 , Niklas Linde 4, Damien Jougnot 2 and Laurent Longuevergne 1 1 CNRS, Géosciences Rennes—UMR 6118, Université Rennes, F-35000 Rennes, France; [email protected] 2 CNRS, EPHE, METIS, Sorbonne Université, F-75005 Paris, France; [email protected] (L.B.); [email protected] (D.J.) 3 Institut de physique du globe de Paris, CNRS, Université de Paris, F-75005 Paris, France; [email protected] 4 Institute of Earth Sciences, University of Lausanne, CH-1015 Lausanne, Switzerland; [email protected] * Correspondence: [email protected] Received: 31 March 2020; Accepted: 21 April 2020; Published: 25 April 2020 Abstract: The vadose zone is the main host of surface and subsurface water exchange and has important implications for ecosystems functioning, climate sciences, geotechnical engineering, and water availability issues. Geophysics provides a means for investigating the subsurface in a non-invasive way and at larger spatial scales than conventional hydrological sensors. Time-lapse hydrogeophysical applications are especially useful for monitoring flow and water content dynamics. Largely dominated by electrical and electromagnetic methods, such applications increasingly rely on seismic methods as a complementary approach to describe the structure and behavior of the vadose zone. To further explore the applicability of active seismics to retrieve quantitative information about dynamic processes in near-surface time-lapse settings, we designed a controlled water infiltration experiment at the Ploemeur Hydrological Observatory (France) during which successive periods of infiltration were followed by surface-based seismic and electrical resistivity acquisitions. -
Geologic Report for the Navarin Basin Planning Area, Bering Sea, A1 Aska
OCS Report MMS 85-0045 Geologic Report for the Navarin Basin Planning Area, Bering Sea, A1 aska Ronald F. Turner Gary C. Martin Tabe 0. Flett David A. Steffy edited by Ronald F. Turner United States Department of the Interior Mineral s Management Service Alaska OCS Region Any use of trade names is for descriptive purposes only and does not constitute endorsement of these products by the Minerals Management Service. Engl ish-Metric Conversion (The following table gives the factors used to convert English units to metric units.) -- - -- - - - - -- multiply English units by to obtain metric units feet meters miles (statute) ki1 ometers acres hectares barrel s (U .S. petrol eum) 1i ters cubic meters inches centimeters pounds per gallon grams per cubic centimeter knots kilometers per hour miles per hour kilometers per hour square miles square ki1 ometers To convert from Fahrenheit (OF) to Celsius (OC), subtract 32 then divide by 1.8, - Abbreviations and Acronyms AAPG Arneri can As soci ati on of Petroleum Geol ogi sts aff. affinis (to have affinities with) APD Appl icdL ior~for Permit to Drill ARC0 Atlantic Richfield Company BHT Bottom Hole Temperature bop. before present BS R Bottom-Simulati ng Ref lector C carbon OC degrees Celsius CDP common depth point cf. confer (to be compared with) Co. Company c ommun . communication COST Continental Offshore Stratigraphic Test 0 darcy, darci es D downthrown DS T Drill Stem Test e, E early, Early E east Abbreviations and Acronyms--Continued EA Environmental Assessment ed . edi tor(s ) , edited by " F degrees Fahrenheit fig. figure ft. -
Geochemistry and Origin of Middle Miocene Volcanic Rocks from Santa Cruz and Anacapa Islands, Southern California Borderland Peter W
Geochemistry and Origin of Middle Miocene Volcanic Rocks from Santa Cruz and Anacapa Islands, Southern California Borderland Peter W. Weigand Department of Geological Sciences California State University Northridge, CA 91330 Cenozoic volcanism that began in the eastern Abstract - Major-oxide and trace-element Mojave Desert about 30 m.y. ago and swept compositions of middle Miocene volcanic rocks irregularly west and north. This extensive from north Santa Cruz and Anacapa Islands are extrusive activity was related closely to complex very similar. In contrast, they are geochemically tectonic activity that included subduction of the distinct from the volcanic clasts from the Blanca Farallon plate whose subduction angle was Formation, of similar age but located south of steepening, and interaction of the Pacific and the Santa Cruz Island fault, which implies North American plates along a lengthening significant strike-slip movement on this fault. transform boundary; this activity additionally The island lavas are also compositionally involved rotation and possible northward distinct from the Conejo Volcanics located translation of crustal blocks. onshore in the Santa Monica Mountains. The The origin of the volcanic rocks in this area island lavas are part of a larger group of about has been variously ascribed to subduction of the 12 similar-aged volcanic suites from the Farallon plate (Weigand 1982; Crowe et al. California Borderland and onshore southern 1976; Higgins 1976), subduction of the Pacific- California that all belong to the calc-alkaline