DOCSLIB.ORG

Deep-Sea Turbidites As Guides to Holocene Earthquake History at the Cascadia Subduction Zone— Alternative Views for a Seismic-Hazard Workshop

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Deep-Sea Turbidites As Guides to Holocene Earthquake History at the Cascadia Subduction Zone— Alternative Views for a Seismic-Hazard Workshop Deep-Sea Turbidites as Guides to Holocene Earthquake History at the Cascadia Subduction Zone— Alternative Views for a Seismic-Hazard Workshop Brian F. Atwater and Gary B. Griggs Open-File Report 2012–1043 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 product and ordering information: World Wide Web: http://www.usgs.gov/pubprod Telephone: 1-888-ASK-USGS For more information on the USGS—the Federal source for science about the Earth, its natural and living resources, natural hazards, and the environment: World Wide Web: http://www.usgs.gov Telephone: 1-888-ASK-USGS Suggested citation: Atwater, B.F., and Griggs, G.B., 2012, Deep-sea turbidites as guides to Holocene earthquake history at the Cascadia Subduction Zone—Alternative views for a seismic-hazard workshop: U.S. Geological Survey Open-File Report 2012–1043, 58 p., available at http://pubs.usgs.gov/of/2012/1043/. 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 material contained within this report. Contents Abstract ......................................................................................................................................................... 1 Introduction .................................................................................................................................................... 2 Evidence Reviewed ....................................................................................................................................3 Diagram Guide ........................................................................................................................................... 4 Turbidite Primer ......................................................................................................................................... 4 Turbidite Names ......................................................................................................................................... 5 Correlations Deduced from Turbidite Counts ................................................................................................. 6 Flow Paths ................................................................................................................................................. 7 Backflooding of Side Valleys .................................................................................................................. 7 Shortcuts from Quinault Canyon to Lower Juan de Fuca Channel ......................................................... 8 Observed Counts ....................................................................................................................................... 8 Mazama Datum ...................................................................................................................................... 9 Complex Turbidites .............................................................................................................................. 10 Time Lags in Cascadia Channel ........................................................................................................... 10 Inequality Between Juan de Fuca and Quinault-Willapa Flows ................................................................ 11 Attrition of Juan de Fuca Flows ............................................................................................................ 12 Inferred Dominance of Quinault-Willapa Flows .................................................................................... 12 Correlation of Individual Turbidites .............................................................................................................. 13 Geophysical Logs .................................................................................................................................... 13 Simplicity and Variability of the Inferred Signatures ............................................................................. 14 Sedimentary Shredding of Seismological Signals ................................................................................ 14 Along-strike Variation in Seismic Shaking ............................................................................................ 15 Radiocarbon Ages and Sedimentation Rates .......................................................................................... 17 Converting Foraminiferal Ages into Turbidite Ages .............................................................................. 17 Further Uncertainty About Rates of Hemipelagic Deposition ................................................................ 18 Further Uncertainty About the Thickness of Hemipelagic Deposits Lost to Erosion ............................. 19 Serial Rupture .......................................................................................................................................... 19 Reasons to Expect Serial Rupture ....................................................................................................... 20 Consistency with Coastal Geology ....................................................................................................... 20 Triggering Distance .............................................................................................................................. 20 Stratigraphic Code ................................................................................................................................ 21 Correlation with Onshore Evidence in Southern Washington and Northernmost Oregon ........................ 21 Onshore Evidence Correlative with Turbidite J2 ................................................................................... 22 Passage of Time Inferred from Burrowed Turbidites and Forested Tidelands ...................................... 22 Consistency with Confluence Test, Geophysical Logs, and Radiocarbon Ages ................................... 23 Consistency with Coastal Land-Level Changes ................................................................................... 24 Mud Turbidites ............................................................................................................................................. 25 Apparent Absence Offshore Washington ................................................................................................. 25 Initiation of Flows Offshore Oregon and Northern California .................................................................... 25 Recommendations for Mapping of Seismic Hazards ................................................................................... 26 Earthquakes of M 9 offshore Southern Washington and Beyond ............................................................. 26 Earthquake Recurrence Offshore Southern British Columbia and Northern Washington ........................ 27 Further Reasearch ................................................................................................................................... 28 Relating Turbidites to Earthquakes ...................................................................................................... 28 iii Putting Numbers on Hazards ............................................................................................................... 29 Acknowledgments and Author Responsibilities ........................................................................................... 29 Appendix—Generating Mud Turbidites Apart from Great Earthquakes ....................................................... 29 References Cited ......................................................................................................................................... 31 Tables 1. Examples of deep-sea turbidites that have been correlated with earthquakes outside of Cascadia ..... 44 2. Counts of turbidites that are known or inferred to postdate the eruption of Mount Mazama (Oregon) 7,800–7,500 sidereal years ago ............................................................................................................ 46 Figures 1. Bathymetric profiles and index map for Cascadia Subduction Zone ..................................................... 49 2. Locations of submarine canyons and channels, and of cores, in the network of Cascadia Channel ..... 50 3. Skeletal views of the confluence test at Cascadia Channel and its tributaries ...................................... 51 4. Previously unpublished details about cores collected in the late 1960s from Cascadia Channel and its tributaries .......................................................................................................................................... 52 5. Geophysical logs used by Goldfinger and others (in press) in correlating turbidites between Juan de Fuca Channel and lower Cascadia Channel .................................................................................... 54 6. Steps used recently in adjusting radiocarbon ages to estimate times of deep-sea turbidite deposition along the Cascadia Subduction Zone .................................................................................. 56 7. Uncertainties in adjustments to radiocarbon ages for turbidites in Cascadia Channel
Load more

Recommended publications
  • Introduction San Andreas Fault: an Overview
    Introduction This volume is a general geology field guide to the San Andreas Fault in the San Francisco Bay Area. The first section provides a brief overview of the San Andreas Fault in context to regional California geology, the Bay Area, and earthquake history with emphasis of the section of the fault that ruptured in the Great San Francisco Earthquake of 1906. This first section also contains information useful for discussion and making field observations associated with fault- related landforms, landslides and mass-wasting features, and the plant ecology in the study region. The second section contains field trips and recommended hikes on public lands in the Santa Cruz Mountains, along the San Mateo Coast, and at Point Reyes National Seashore. These trips provide access to the San Andreas Fault and associated faults, and to significant rock exposures and landforms in the vicinity. Note that more stops are provided in each of the sections than might be possible to visit in a day. The extra material is intended to provide optional choices to visit in a region with a wealth of natural resources, and to support discussions and provide information about additional field exploration in the Santa Cruz Mountains region. An early version of the guidebook was used in conjunction with the Pacific SEPM 2004 Fall Field Trip. Selected references provide a more technical and exhaustive overview of the fault system and geology in this field area; for instance, see USGS Professional Paper 1550-E (Wells, 2004). San Andreas Fault: An Overview The catastrophe caused by the 1906 earthquake in the San Francisco region started the study of earthquakes and California geology in earnest.
    [Show full text]
  • Hildebrand Department of Petroleum and Geosystems Engineering Page
    Hildebrand Department of Petroleum and Geosystems Engineering THE UNIVERSITY OF TEXAS AT AUSTIN Cockrell School of Engineering Standard Resume FULL NAME: Hilary Clement Olson TITLE: Senior Lecturer DEPARTMENT: Hildebrand Department of Petroleum and Geosystems Engineering EDUCATION: Stanford University Geology Ph.D. Summer 1988 University of Notre Dame Earth Sciences B.S. Spring 1983 Université Catholique de L'Ouest Diplôme de Langue Française Spring 1981 CURRENT AND PREVIOUS ACADEMIC POSITIONS: The University of Texas at Austin Center for Petroleum and Program September 2015 - Present Geosystems Engineering Manager The University of Texas at Austin Hildebrand Department of Sr. Lecturer September 2019 – present Petroleum and Geosystems Lecturer January 2013 – August Engineering 2019 The University of Texas at Austin Center for Petroleum and Research September 2013 – August Geosystems Engineering Associate 2015 The University of Texas at Austin Department of Geological Lecturer January 2011 – May 2013 Sciences The University of Texas at Austin Institute for Geophysics Research May 2007 – August 2013 Scientist Associate V Huston-Tillotson University Special Topics in the Instructor January 2006 – May 2006 Geosciences The University of Texas at Austin Institute for Geophysics Research September 1998 – May Associate 2007 The University of Texas at Austin Institute for Geophysics Research June 1996 – August 1998 Fellow The University of Texas at Austin Department of Geological Lecturer January 1996 – May 1996 Sciences The University of Texas
    [Show full text]
  • New Oregon Tsunami Simulation Scenarios, Published Data, and Probable Effect on the Oregon Building Code
    New Oregon Tsunami Simulation Scenarios, Published Data, and Probable Effect on the Oregon Building Code George R. Priest, Oregon Dept. of Geology and Mineral Industries Presentation to the workshop on Designing for Tsunamis: New Oregon Data & Anticipated Changes to the Building Code Portland State Office Building, Portland, Oregon May 18, 2015 Designing for Tsunamis 5-18-15 Cascadia Subduction Zone (CSZ) North American Plate Overrides Juan de Fuca Plate Along Cascadia Subduction Zone at a rate of 1.5 inches/year Designing for Tsunamis 5-18-15 What does the 10,000 year history of ~40 great Cascadia earthquakes and tsunamis mean for probabilistic tsunami hazard analysis (PTHA)? The last big Cascadia earthquake and local tsunami in the Northwest was January 26, 1700 at ~9:00 PM. (Satake et al., 2003, Journ. Geophys. Res., v 108, no. B11, p. 2535.) Designing for Tsunamis 5-18-15 Turbidites in a deep sea core. (picture provided by Chris Goldfinger, 2010) Taken from Atwater (2005) Deep Sea Clay Turbidite Sand Designing for Tsunamis 5-18-15 Cascadia Fault Rupture Lengths from Turbidite Data ~40 earthquakes over the last 10,000 years 19 earthquakes 4 earthquakes 7 earthquakes 10 earthquakes Recurrence Grays Harbor Seaside Newport Coos Bay Mw Mw Mw Mw ~9 Brookings 500 8.5-8.8 8.5-8.3 7.6-8.4 430 yrs 320 yrs 240 yrs yrs Eureka CONCLUSION: Recurrence of tsunamis ≥~200 yrs dominated by Cascadia sources. Illustration modified from Goldfinger et al. (2012) Designing for Tsunamis 5-18-15 Tsunami Hazard Assessment Focused on (1) Defining Cascadia Sources
    [Show full text]
  • Exploring Options for an Olympic Coast Ocean Acidification Sentinel Site (Oases)
    Exploring Options for an Olympic Coast Ocean Acidification Sentinel Site (OASeS) Workshop Proceedings September 2016 Contents Background ..................................................................................................................................... 1 Olympic Coast ............................................................................................................................ 1 Ocean Acidification .................................................................................................................... 1 Ocean Acidification Sentinel Site (OASeS) Workshop Background ......................................... 2 Workshop Goals.......................................................................................................................... 3 Panel Discussion Summaries .......................................................................................................... 3 Science in National Marine Sanctuaries and OCNMS ............................................................... 3 i. i.Panelists: Steve Giddings, Liam Atrim, Scott Noakes, Lee Whitford Partners and Activities ................................................................................................................ 5 i. Panelists: Libby Jewett, Jan Newton, Richard Feely, Steve Fradkin, Paul McElhany, Joe Shumacker Education and Communication ................................................................................................... 7 i. Panelists: Laura Francis, Christopher Krembs, Jacqueline Laverdure, Angie
    [Show full text]
  • Proquest Dissertations
    GEOLOGICAL INTERPRETATIONS OF A LOW-BACKSCATTER ANOMALY FOUND IN 12-KHZ MULTIBEAM DATA ON THE NEW JERSEY CONTINENTAL MARGIN BY EDWARD M. SWEENEY, JR. BA, Bowdoin College, 2003 THESIS Submitted to the University of New Hampshire in Partial Fulfillment of the Requirements for the Degree of Master of Science in Earth Sciences: Ocean Mapping December, 2008 UMI Number: 1463240 INFORMATION TO USERS The quality of this reproduction is dependent upon the quality of the copy submitted. Broken or indistinct print, colored or poor quality illustrations and photographs, print bleed-through, substandard margins, and improper alignment can adversely affect reproduction. In the unlikely event that the author did not send a complete manuscript and there are missing pages, these will be noted. Also, if unauthorized copyright material had to be removed, a note will indicate the deletion. ® UMI UMI Microform 1463240 Copyright 2009 by ProQuest LLC. All rights reserved. This microform edition is protected against unauthorized copying under Title 17, United States Code. ProQuest LLC 789 E. Eisenhower Parkway PO Box 1346 Ann Arbor, Ml 48106-1346 This thesis has been examined and approved. Thesis Director James V. Gardner Research Professor of Earth Sciences Larry X. Mayer Professor of Ocean Engineering and Earth Sciences Joel E. Johnson Assistant Professor of Earth Sciences T4* William A Schwab Geologist, U.S. Geological Survey Octet* lb* S»o9 Date DEDICATION This thesis is dedicated to my family and friends for believing in me during my road through graduate school and especially to my mom and dad for always pushing me to do my best both academically and in life.
    [Show full text]
  • Turbidites in a Jar
    Activity— Turbidites in a Jar Sand Dikes & Marine Turbidites Paleoseismology is the study of the timing, location, and magnitude of prehistoric earthquakes preserved in the geologic record. Knowledge of the pattern of earthquakes in a region and over long periods of time helps to understand the long- term behavior of faults and seismic zones and is used to forecast the future likelihood of damaging earthquakes. Introduction Note: Glossary is in the activity description Sand dikes are sedimentary dikes consisting of sand that has been squeezed or injected upward into a fissure during Science Standards an earthquake. (NGSS; pg. 287) To figure out the earthquake hazard of an area, scientists need to know how often the largest earthquakes occur. • From Molecules to Organisms—Structures Unfortunately (from a scientific perspective), the time and Processes: MS-LS1-8 between major earthquakes is much longer than the • Motion and Stability—Forces­­ and time period for which we have modern instrumental Interactions: MS-PS2-2 measurements or even historical accounts of earthquakes. • Earth’s Place in the Universe: MS-ESS1-4, Fortunately, scientists have found a sufficiently long record HS-ESS1-5 of past earthquakes that is preserved in the rock and soil • Earth’s Systems: HS-ESS2-1, MS-ESS2-2, beneath our feet. The unraveling of this record is the realm MS-ESS2-3 of a field called “paleoseismology.” • Earth and Human Activity: HS-ESS3-1, In the Central United States, abundant sand blows are MS-ESS3-2 studied by paleoseismologists. These patches of sand erupt onto the ground when waves from a large earthquake pass through wet, loose sand.
    [Show full text]
  • January 2016 NEWS COVERAGE PERIOD from JANUARY 25TH to JANURAY 31ST 2016 GOVT BURDENS GAS CONSUMERS with RS101BN to FINANCE PIPELINES Dawn, January 29Th, 2016
    January 2016 NEWS COVERAGE PERIOD FROM JANUARY 25TH TO JANURAY 31ST 2016 GOVT BURDENS GAS CONSUMERS WITH RS101BN TO FINANCE PIPELINES Dawn, January 29th, 2016 KHALEEQ KIANI ISLAMABAD: The Economic Coordination Committee (ECC) of the Cabinet on Thursday decided to charge consumers of the two gas utilities Rs101 billion to partly finance pipeline network. At a charged meeting presided over by Finance Minister Ishaq Dar, the committee also approved Rs3 per unit reduction in future power tariff for industrial consumers previously announced by the prime minister in December. It also regularised import of first six cargoes of the liquefied natural gas (LNG) in April-May last year through a floating storage terminal, but deferred a final decision on LNG sales and purchase agreement between Qatargas and Pakistan State Oil (PSO) until Friday. “It was a bad day for member gas (Oil and Gas Regulatory Authority, or Ogra) Amir Naseem,” said a cabinet member who attended the meeting, adding that the finance minister lost his temper at the beginning of the meeting over Ogra’s written comments against petroleum ministry’s summary on Rs101bn financing arrangement for gas companies. Ogra earlier opposed the recovery of Rs101bn from consumers through tariff, saying the pipeline projects should be financed out of Gas Infrastructure Development Cess (GIDC) already being collected from consumers. The regulator believed that it could not allow under the GIDC law the “double taxation” through gas tariff. Consumers, who were already paying GIDC for pipeline infrastructure, could not be burdened again with financing for repayment of Rs101bn loan along with 17 per cent return on assets to be created by the gas companies through these loans.
    [Show full text]
  • Deep-Water Turbidites As Holocene Earthquake Proxies: the Cascadia Subduction Zone and Northern San Andreas Fault Systems
    University of New Hampshire University of New Hampshire Scholars' Repository Faculty Publications 10-1-2003 Deep-water turbidites as Holocene earthquake proxies: the Cascadia subduction zone and Northern San Andreas Fault systems Chris Goldfinger Oregon State University C. Hans Nelson Universidad de Granada Joel E. Johnson University of New Hampshire, Durham, [email protected] Follow this and additional works at: https://scholars.unh.edu/faculty_pubs Recommended Citation Goldfinger, C. Nelson, C.H., and Johnson, J.E., 2003, Deep-Water Turbidites as Holocene Earthquake Proxies: The Cascadia Subduction Zone and Northern San Andreas Fault Systems. Annals of Geophysics, 46(5), 1169-1194. http://dx.doi.org/10.4401%2Fag-3452 This Article is brought to you for free and open access by University of New Hampshire Scholars' Repository. It has been accepted for inclusion in Faculty Publications by an authorized administrator of University of New Hampshire Scholars' Repository. For more information, please contact [email protected]. ANNALS OF GEOPHYSICS, VOL. 46, N. 5, October 2003 Deep-water turbidites as Holocene earthquake proxies: the Cascadia subduction zone and Northern San Andreas Fault systems Chris Goldfinger (1),C. Hans Nelson (2) (*), Joel E. Johnson (1)and the Shipboard Scientific Party (1) College of Oceanic and Atmospheric Sciences, Oregon State University, Corvallis, Oregon, U.S.A. (2) Department of Oceanography, Texas A & M University, College Station, Texas, U.S.A. Abstract New stratigraphic evidence from the Cascadia margin demonstrates that 13 earthquakes ruptured the margin from Vancouver Island to at least the California border following the catastrophic eruption of Mount Mazama. These 13 events have occurred with an average repeat time of ¾ 600 years since the first post-Mazama event ¾ 7500 years ago.
    [Show full text]
  • Ocean Drilling Program Leg 181 Scientific Prospectus
    OCEAN DRILLING PROGRAM LEG 181 SCIENTIFIC PROSPECTUS SOUTHWEST PACIFIC GATEWAYS Dr. Robert M. Carter Dr. I.N. McCave Co-Chief Scientist Co-Chief Scientist Department of Geology Department of Earth Sciences James Cook University University of Cambridge Townsville Downing Street QLD 4811 Cambridge CB2 3EQ Australia United Kingdom Dr. Carl Richter Staff Scientist Ocean Drilling Program Texas A&M University Research Park 1000 Discovery Drive College Station, Texas 77845-9547 U.S.A. ___________________ __________________ Jack Baldauf Carl Richter Deputy Director Leg Project Manager of Science Operations Science Services ODP/TAMU ODP/TAMU March 1998 Material in this publication may be copied without restraint for library, abstract service, educational, or personal research purposes; however, republication of any portion requires the written consent of the Director, Ocean Drilling Program, Texas A&M University Research Park, 1000 Discovery Drive, College Station, Texas 77845-9547, U.S.A., as well as appropriate acknowledgment of this source. Scientific Prospectus No. 81 First Printing 1998 Distribution Electronic copies of this publication may be obtained from the ODP Publications Home Page on the World Wide Web at http://www-odp.tamu.edu/publications. D I S C L A I M E R This publication was prepared by the Ocean Drilling Program, Texas A&M University, as an account of work performed under the international Ocean Drilling Program, which is managed by Joint Oceanographic Institutions, Inc., under contract with the National Science Foundation.
    [Show full text]
  • Advanced Gas Hydrate Reservoir Modeling Using Rock Physics Techniques Project Period (10/1/2012-3/31/2016)
    OIL & GAS DOE Award No.: DE-FE0010160 Final Technical Report (Period Ending 03/31/2016) Advanced Gas Hydrate Reservoir Modeling Using Rock Physics Techniques Project Period (10/1/2012-3/31/2016) Submitted by: Dan McConnell _____________________________________ Signature Fugro GeoConsulting, Inc., dba Fugro Marine Geoservices, Inc. DUNS #:118972301 6100 Hillcroft Houston, Texas 77081 Email: [email protected] Phone number: (713) 778-6801 Prepared for: United States Department of Energy National Energy Technology Laboratory December 30, 2017 Office of Fossil Energy DISCLAIMER This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof. ABSTRACT Prospecting for high saturation gas hydrate deposits can be greatly aided with improved approaches to seismic interpretation and especially if sets of seismic attributes can be shown as diagnostic or direct hydrocarbon indicators for high saturation gas hydrates in sands that would be of most interest for gas hydrate production.
    [Show full text]
  • EA for Cascadia Spring/Summer Survey 2020
    Draft Environmental Assessment/Analysis of a Marine Geophysical Survey by R/V Marcus G. Langseth of the Cascadia Subduction Zone in the Northeast Pacific Ocean, Late Spring/Summer 2020 Prepared for Lamont-Doherty Earth Observatory 61 Route 9W, P.O. Box 1000 Palisades, NY 10964-8000 and National Science Foundation Division of Ocean Sciences 4201 Wilson Blvd., Suite 725 Arlington, VA 22230 by LGL Ltd., environmental research associates 22 Fisher St., POB 280 King City, Ont. L7B 1A6 21 November 2019 LGL Report FA0186-01A Table of Contents TABLE OF CONTENTS LIST OF FIGURES .......................................................................................................................................... iv LIST OF TABLES ............................................................................................................................................. v ABSTRACT .................................................................................................................................................... vi LIST OF ACRONYMS ..................................................................................................................................... ix I PURPOSE AND NEED ................................................................................................................................... 1 1.1 Mission of NSF ................................................................................................................................ 1 1.2 Purpose of and Need for the Proposed Action ................................................................................
    [Show full text]
  • A Regional Synthesis Paul E
    Document generated on 09/28/2021 9:30 p.m. Atlantic Geology A Regional Synthesis Paul E. Schenk Volume 11, Number 1, April 1975 URI: https://id.erudit.org/iderudit/ageo11_1rep04 See table of contents Publisher(s) Maritime Sediments Editorial Board ISSN 0843-5561 (print) 1718-7885 (digital) Explore this journal Cite this article Schenk, P. E. (1975). A Regional Synthesis. Atlantic Geology, 11(1), 17–24. All rights reserved © Maritime Sediments, 1975 This document is protected by copyright law. Use of the services of Érudit (including reproduction) is subject to its terms and conditions, which can be viewed online. https://apropos.erudit.org/en/users/policy-on-use/ This article is disseminated and preserved by Érudit. Érudit is a non-profit inter-university consortium of the Université de Montréal, Université Laval, and the Université du Québec à Montréal. Its mission is to promote and disseminate research. https://www.erudit.org/en/ 17 A Regional Synthesis PAUL E. SCHENK, Department of Geology, Dalhousie University, Halifax, Nova Scotia Introduction southern zone (the Meguma Belt). The Avalon Plat­ form is composed of Late Cryptozoic and Early The Devonian Acadian orogeny divides the Nova Paleozoic shelf sedimentary rocks and volcanics. Scotia section into two contrasting assemblages: In contrast, the Meguma Belt contains an Early to (1) the pre-orogenic units, which are mainly marine; Middle Paleozoic succession which shows evidence and (2) the post-orogenic units, which are mainly of shoaling upwards from deep-sea fans to paralic redbeds with later marine overlap. The stratigraph­ lithosomes. The Belt extends seaward 200 km toward ic section is applied to Folk's tectonic cycle and the present continental slope.
    [Show full text]