The Ocean Floor

Total Page：16

File Type：pdf, Size：1020Kb

SOL 5.6 PART 1 Earth/Space Systems & Cycles NOTEPAGE FOR STUDENT The Ocean Floor The oceans of the world cover about seventy percent of Earth’s surface; this is over 140 million square miles! The oceans vary in depth from the shallow waters of the continental shelf to the deep, dark waters of ocean trenches. If we went on a field trip across the ocean floor, we would see the same landforms that we see on land – mountains, valleys, hills, and plains! Some important features of the ocean floor include the continental shelf, the continental slope, the continental rise, the abyssal plain, and ocean trenches. The continental shelf is that shallow part of the ocean floor that begins at the shoreline and gently slopes underwater to an average depth of about 430 feet. It is covered with thick layers of sediment (sand, mud, and rocks). When you play in the water at the beach, you are on the continental shelf. The continental slope begins at the edge of the continental shelf and plunges down to depths of over two miles. This area is also covered with thick layers of sand, mud, and rocks. The continental rise is a gently sloping area that connects the steep walls of the continental slope to the bottom of the ocean floor. It, too, is covered with thick layers of sand, mud, and rocks. The abyssal plain is the flat area of the ocean floor. It is covered with sand, mud, and plant and animal remains. Located on this flat plain are undersea mountains called seamounts that are formed by erupting volcanoes. Ocean trenches are very deep and similar to canyons on land. The deepest ocean trench on Earth is located in the Pacific Ocean. It is called the Marianas Trench and is 36,198 feet in depth. The Grand Canyon, which is the largest canyon on Earth, is only 5,300 feet deep. Wow! ©2012 .

Copy Link

Recommended publications

Continental Shelf the Last Maritime Zone
Continental Shelf The Last Maritime Zone The Last Maritime Zone Published by UNEP/GRID-Arendal Copyright © 2009, UNEP/GRID-Arendal ISBN: 978-82-7701-059-5 Printed by Birkeland Trykkeri AS, Norway Disclaimer Any views expressed in this book are those of the authors and do not necessarily reflect the views or policies of UNEP/GRID-Arendal or contributory organizations. The designations employed and the presentation of material in this book do not imply the expression of any opinion on the part of the organizations concerning the legal status of any country, territory, city or area of its authority, or deline- ation of its frontiers and boundaries, nor do they imply the validity of submissions. All information in this publication is derived from official material that is posted on the website of the UN Division of Ocean Affairs and the Law of the Sea (DOALOS), which acts as the Secretariat to the Com- mission on the Limits of the Continental Shelf (CLCS): www.un.org/ Depts/los/clcs_new/clcs_home.htm. UNEP/GRID-Arendal is an official UNEP centre located in Southern Norway. GRID-Arendal’s mission is to provide environmental informa- tion, communications and capacity building services for information management and assessment. The centre’s core focus is to facili- tate the free access and exchange of information to support decision making to secure a sustainable future. www.grida.no. Continental Shelf The Last Maritime Zone Continental Shelf The Last Maritime Zone Authors and contributors Tina Schoolmeester and Elaine Baker (Editors) Joan Fabres Øystein Halvorsen Øivind Lønne Jean-Nicolas Poussart Riccardo Pravettoni (Cartography) Morten Sørensen Kristina Thygesen Cover illustration Alex Mathers Language editor Harry Forster (Interrelate Grenoble) Special thanks to Yannick Beaudoin Janet Fernandez Skaalvik Lars Kullerud Harald Sund (Geocap AS) Continental Shelf The Last Maritime Zone Foreword During the past decade, many coastal States have been engaged in peacefully establish- ing the limits of their maritime jurisdiction.
[Show full text]
Geologists Suggest Horseshoe Abyssal Plain May Be Start of a Subduction Zone 8 May 2019, by Bob Yirka
Geologists suggest Horseshoe Abyssal Plain may be start of a subduction zone 8 May 2019, by Bob Yirka against one another. Over by the Iberian Peninsula, the opposite appears to be happening—the African and Eurasian plates are pulling apart as the former creeps east toward the Americas. Duarte noted that back in 2012, other researchers conducting seismic wave tests found what appeared to be a dense mass of unknown material beneath the epicenter of the 1969 quake. Some in the field suggested it could be the start of a subduction zone. Then, last year, another team conducted high-resolution imaging of the area and also found evidence of the mass, confirming that it truly existed. Other research has shown that the area just above the mass experiences routine tiny earthquakes. Duarte suggests the evidence to date indicates that the bottom of the plate is peeling away. This could happen, he explained, due to serpentinization in which water percolates through plate fractures and reacts with material beneath the surface, resulting A composite image of the Western hemisphere of the in the formation of soft green minerals. The soft Earth. Credit: NASA mineral layer, he suggests, is peeling away. And if that is the case, then it is likely the area is in the process of creating a subduction zone. He reports that he and his team members built models of their A team of geologists led by João Duarte gave a ideas and that they confirmed what he suspected. presentation at this past month's European The earthquakes were the result of the process of Geosciences Union meeting that included a birthing a new subduction zone.
[Show full text]
Hydrothermal Vents. Teacher's Notes
Hydrothermal Vents Hydrothermal Vents. Teacher’s notes. A hydrothermal vent is a fissure in a planet's surface from which geothermally heated water issues. They are usually volcanically active. Seawater penetrates into fissures of the volcanic bed and interacts with the hot, newly formed rock in the volcanic crust. This heated seawater (350-450°) dissolves large amounts of minerals. The resulting acidic solution, containing metals (Fe, Mn, Zn, Cu) and large amounts of reduced sulfur and compounds such as sulfides and H2S, percolates up through the sea floor where it mixes with the cold surrounding ocean water (2-4°) forming mineral deposits and different types of vents. In the resulting temperature gradient, these minerals provide a source of energy and nutrients to chemoautotrophic organisms that are, thus, able to live in these extreme conditions. This is an extreme environment with high pressure, steep temperature gradients, and high concentrations of toxic elements such as sulfides and heavy metals. Black and white smokers Some hydrothermal vents form a chimney like structure that can be as 60m tall. They are formed when the minerals that are dissolved in the fluid precipitates out when the super-heated water comes into contact with the freezing seawater. The minerals become particles with high sulphur content that form the stack. Black smokers are very acidic typically with a ph. of 2 (around that of vinegar). A black smoker is a type of vent found at depths typically below 3000m that emit a cloud or black material high in sulphates. White smokers are formed in a similar way but they emit lighter-hued minerals, for example barium, calcium and silicon.
[Show full text]
Introduction to Co2 Chemistry in Sea Water
INTRODUCTION TO CO2 CHEMISTRY IN SEA WATER Andrew G. Dickson Scripps Institution of Oceanography, UC San Diego Mauna Loa Observatory, Hawaii Monthly Average Carbon Dioxide Concentration Data from Scripps CO Program Last updated August 2016 2 ? 410 400 390 380 370 2008; ~385 ppm 360 350 Concentration (ppm) 2 340 CO 330 1974; ~330 ppm 320 310 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010 2015 Year EFFECT OF ADDING CO2 TO SEA WATER 2− − CO2 + CO3 +H2O ! 2HCO3 O C O CO2 1. Dissolves in the ocean increase in decreases increases dissolved CO2 carbonate bicarbonate − HCO3 H O O also hydrogen ion concentration increases C H H 2. Reacts with water O O + H2O to form bicarbonate ion i.e., pH = –lg [H ] decreases H+ and hydrogen ion − HCO3 and saturation state of calcium carbonate decreases H+ 2− O O CO + 2− 3 3. Nearly all of that hydrogen [Ca ][CO ] C C H saturation Ω = 3 O O ion reacts with carbonate O O state K ion to form more bicarbonate sp (a measure of how “easy” it is to form a shell) M u l t i p l e o b s e r v e d indicators of a changing global carbon cycle: (a) atmospheric concentrations of carbon dioxide (CO2) from Mauna Loa (19°32´N, 155°34´W – red) and South Pole (89°59´S, 24°48´W – black) since 1958; (b) partial pressure of dissolved CO2 at the ocean surface (blue curves) and in situ pH (green curves), a measure of the acidity of ocean water.
[Show full text]
Sea-Level Rise for the Coasts of California, Oregon, and Washington: Past, Present, and Future
Sea-Level Rise for the Coasts of California, Oregon, and Washington: Past, Present, and Future As more and more states are incorporating projections of sea-level rise into coastal planning efforts, the states of California, Oregon, and Washington asked the National Research Council to project sea-level rise along their coasts for the years 2030, 2050, and 2100, taking into account the many factors that affect sea-level rise on a local scale. The projections show a sharp distinction at Cape Mendocino in northern California. South of that point, sea-level rise is expected to be very close to global projections; north of that point, sea-level rise is projected to be less than global projections because seismic strain is pushing the land upward. ny significant sea-level In compliance with a rise will pose enor- 2008 executive order, mous risks to the California state agencies have A been incorporating projec- valuable infrastructure, devel- opment, and wetlands that line tions of sea-level rise into much of the 1,600 mile shore- their coastal planning. This line of California, Oregon, and study provides the first Washington. For example, in comprehensive regional San Francisco Bay, two inter- projections of the changes in national airports, the ports of sea level expected in San Francisco and Oakland, a California, Oregon, and naval air station, freeways, Washington. housing developments, and sports stadiums have been Global Sea-Level Rise built on fill that raised the land Following a few thousand level only a few feet above the years of relative stability, highest tides. The San Francisco International Airport (center) global sea level has been Sea-level change is linked and surrounding areas will begin to flood with as rising since the late 19th or to changes in the Earth’s little as 40 cm (16 inches) of sea-level rise, a early 20th century, when climate.
[Show full text]
Relationship Between Continental Rise Development and Palaeo-Ice Sheet Dynamics, Northern Antarctic Peninsula Pacific Margin
ARTICLE IN PRESS Quaternary Science Reviews 25 (2006) 933–944 Relationship between continental rise development and palaeo-ice sheet dynamics, Northern Antarctic Peninsula Pacific margin David Amblasa, Roger Urgelesa, Miquel Canalsa,Ã, Antoni M. Calafata, Michele Rebescob, Angelo Camerlenghia, Ferran Estradac, Marc De Batistd, John E. Hughes-Clarkee aGRC Geocie`ncies Marines, Universitat de Barcelona, Martı´ i Franque`s s/n, E-08028 Barcelona, Spain bIstituto Nazionale di Oceanografia e di Geofisica Sperimentale (OGS), Borgo Grotta Gigante 42/c, 34010 Sgonico, Trieste, Italy cCSIC Institut de Cie`ncies del Mar, Passeig Marı´tim Barceloneta 37-49, 08003 Barcelona, Spain dRenard Centre of Marine Geology, Ghent University, Krijgslaan 281 S8, B-9000 Gent, Belgium eOcean Mapping Group, University of New Brunswick, Fredericton, New Brunswick, Canada E3B 5A3 Received 17 December 2004; accepted 10 July 2005 Abstract Acquisition of swath bathymetry data west of the North Antarctic Peninsula (NAP), between 631S and 661S, and its integration with the predicted seafloor topography of Smith and Sandwell [Global seafloor topography from satellite altimetry and ship depth soundings. Science 277, 1956–1962.] reveal the links between the continental rise depositional systems and the NAP palaeo-ice sheet dynamics. The NAP Pacific margin consists of a wide continental shelf dissected by several troughs, tens of kilometres wide and long. The Biscoe Trough, which has been almost entirely surveyed with multibeam sonar, shows spectacular fan-shaped streamlining sea-floor morphologies revealing the presence of ice streams during the Last Glacial Maximum. In the study area the continental rise comprises the six northernmost sediment mounds of the NAP Pacific margin and the canyon-channel systems between them.
[Show full text]
Causes of Sea Level Rise
FACT SHEET Causes of Sea OUR COASTAL COMMUNITIES AT RISK Level Rise What the Science Tells Us HIGHLIGHTS From the rocky shoreline of Maine to the busy trading port of New Orleans, from Roughly a third of the nation’s population historic Golden Gate Park in San Francisco to the golden sands of Miami Beach, lives in coastal counties. Several million our coasts are an integral part of American life. Where the sea meets land sit some of our most densely populated cities, most popular tourist destinations, bountiful of those live at elevations that could be fisheries, unique natural landscapes, strategic military bases, financial centers, and flooded by rising seas this century, scientific beaches and boardwalks where memories are created. Yet many of these iconic projections show. These cities and towns— places face a growing risk from sea level rise. home to tourist destinations, fisheries, Global sea level is rising—and at an accelerating rate—largely in response to natural landscapes, military bases, financial global warming. The global average rise has been about eight inches since the centers, and beaches and boardwalks— Industrial Revolution. However, many U.S. cities have seen much higher increases in sea level (NOAA 2012a; NOAA 2012b). Portions of the East and Gulf coasts face a growing risk from sea level rise. have faced some of the world’s fastest rates of sea level rise (NOAA 2012b). These trends have contributed to loss of life, billions of dollars in damage to coastal The choices we make today are critical property and infrastructure, massive taxpayer funding for recovery and rebuild- to protecting coastal communities.
[Show full text]
Natural Variability of the Arctic Ocean Sea Ice During the Present Interglacial
Natural variability of the Arctic Ocean sea ice during the present interglacial Anne de Vernala,1, Claude Hillaire-Marcela, Cynthia Le Duca, Philippe Robergea, Camille Bricea, Jens Matthiessenb, Robert F. Spielhagenc, and Ruediger Steinb,d aGeotop-Université du Québec à Montréal, Montréal, QC H3C 3P8, Canada; bGeosciences/Marine Geology, Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, 27568 Bremerhaven, Germany; cOcean Circulation and Climate Dynamics Division, GEOMAR Helmholtz Centre for Ocean Research, 24148 Kiel, Germany; and dMARUM Center for Marine Environmental Sciences and Faculty of Geosciences, University of Bremen, 28334 Bremen, Germany Edited by Thomas M. Cronin, U.S. Geological Survey, Reston, VA, and accepted by Editorial Board Member Jean Jouzel August 26, 2020 (received for review May 6, 2020) The impact of the ongoing anthropogenic warming on the Arctic such an extrapolation. Moreover, the past 1,400 y only encom- Ocean sea ice is ascertained and closely monitored. However, its pass a small fraction of the climate variations that occurred long-term fate remains an open question as its natural variability during the Cenozoic (7, 8), even during the present interglacial, on centennial to millennial timescales is not well documented. i.e., the Holocene (9), which began ∼11,700 y ago. To assess Here, we use marine sedimentary records to reconstruct Arctic Arctic sea-ice instabilities further back in time, the analyses of sea-ice fluctuations. Cores collected along the Lomonosov Ridge sedimentary archives is required but represents a challenge (10, that extends across the Arctic Ocean from northern Greenland to 11). Suitable sedimentary sequences with a reliable chronology the Laptev Sea were radiocarbon dated and analyzed for their and biogenic content allowing oceanographical reconstructions micropaleontological and palynological contents, both bearing in- can be recovered from Arctic Ocean shelves, but they rarely formation on the past sea-ice cover.
[Show full text]
Coastal and Ocean Engineering
May 18, 2020 Coastal and Ocean Engineering John Fenton Institute of Hydraulic Engineering and Water Resources Management Vienna University of Technology, Karlsplatz 13/222, 1040 Vienna, Austria URL: http://johndfenton.com/ URL: mailto:[email protected] Abstract This course introduces maritime engineering, encompassing coastal and ocean engineering. It con- centrates on providing an understanding of the many processes at work when the tides, storms and waves interact with the natural and human environments. The course will be a mixture of descrip- tion and theory – it is hoped that by understanding the theory that the practicewillbemadeallthe easier. There is nothing quite so practical as a good theory. Table of Contents References ....................... 2 1. Introduction ..................... 6 1.1 Physical properties of seawater ............. 6 2. Introduction to Oceanography ............... 7 2.1 Ocean currents .................. 7 2.2 El Niño, La Niña, and the Southern Oscillation ........10 2.3 Indian Ocean Dipole ................12 2.4 Continental shelf ﬂow ................13 3. Tides .......................15 3.1 Introduction ...................15 3.2 Tide generating forces and equilibrium theory ........15 3.3 Dynamic model of tides ...............17 3.4 Harmonic analysis and prediction of tides ..........19 4. Surface gravity waves ..................21 4.1 The equations of ﬂuid mechanics ............21 4.2 Boundary conditions ................28 4.3 The general problem of wave motion ...........29 4.4 Linear wave theory .................30 4.5 Shoaling, refraction and breaking ............44 4.6 Diffraction ...................50 4.7 Nonlinear wave theories ...............51 1 Coastal and Ocean Engineering John Fenton 5. The calculation of forces on ocean structures ...........54 5.1 Structural element much smaller than wavelength – drag and inertia forces .....................54 5.2 Structural element comparable with wavelength – diffraction forces ..56 6.
[Show full text]
Mapping the Canyon
Deep East 2001— Grades 9-12 Focus: Bathymetry of Hudson Canyon Mapping the Canyon FOCUS Part III: Bathymetry of Hudson Canyon ❒ Library Books GRADE LEVEL AUDIO/VISUAL EQUIPMENT 9 - 12 Overhead Projector FOCUS QUESTION TEACHING TIME What are the differences between bathymetric Two 45-minute periods maps and topographic maps? SEATING ARRANGEMENT LEARNING OBJECTIVES Cooperative groups of two to four Students will be able to compare and contrast a topographic map to a bathymetric map. MAXIMUM NUMBER OF STUDENTS 30 Students will investigate the various ways in which bathymetric maps are made. KEY WORDS Topography Students will learn how to interpret a bathymet- Bathymetry ric map. Map Multibeam sonar ADAPTATIONS FOR DEAF STUDENTS Canyon None required Contour lines SONAR MATERIALS Side-scan sonar Part I: GLORIA ❒ 1 Hudson Canyon Bathymetry map trans- Echo sounder parency ❒ 1 local topographic map BACKGROUND INFORMATION ❒ 1 USGS Fact Sheet on Sea Floor Mapping A map is a flat representation of all or part of Earth’s surface drawn to a specific scale Part II: (Tarbuck & Lutgens, 1999). Topographic maps show elevation of landforms above sea level, ❒ 1 local topographic map per group and bathymetric maps show depths of land- ❒ 1 Hudson Canyon Bathymetry map per group forms below sea level. The topographic eleva- ❒ 1 Hudson Canyon Bathymetry map trans- tions and the bathymetric depths are shown parency ❒ with contour lines. A contour line is a line on a Contour Analysis Worksheet map representing a corresponding imaginary 59 Deep East 2001— Grades 9-12 Focus: Bathymetry of Hudson Canyon line on the ground that has the same elevation sonar is the multibeam sonar.
[Show full text]
On the Circulation and Water Masses Over the Antarctic Continental Slope and Rise Between 80 and 1503E Nathaniel L
Deep-Sea Research II 47 (2000) 2299}2326 On the circulation and water masses over the Antarctic continental slope and rise between 80 and 1503E Nathaniel L. Bindo!! *, Mark A. Rosenberg!, Mark J. Warner" !Antarctic Co-operative Research Centre, GPO Box 252-80, Hobart, Tasmania 7001, Australia "School of Oceanography, University of Washington, Seattle, USA Received 18 December 1998; received in revised form 18 October 1999; accepted 22 December 1999 Abstract The circulation and water masses in the region between 80 and 1503E and from the Antarctic continental shelf to the Southern Boundary of the Antarctic Circumpolar Current (ACC) (&623S) are described from hydrographic and surface drifter data taken as part of the multi-disciplinary experiment, Baseline Research on Oceanography Krill and the Environment (BROKE). Two types of bottom water are identi"ed, Adelie Land Bottom Water, formed locally between 140 and 1503E, and Ross Sea Bottom Water. Ross Sea Bottom Water is found only at 1503E, whereas Adelie Land Bottom Water is found throughout the survey region. The bottom water mass properties become progressively warmer and saltier to the west, suggesting a westward #ow. All of the eight meridional CTD sections show an Antarctic Slope Front of varying strength and position with respect to the shelf break. In the water formation areas (between 140 and 1503E) and 1043E, the Antarctic Slope Front is more `Va shaped, while elsewhere it is one-sided. The shape of the slope front, and the presence or absence of water formation there, are consistent with other meridional sections in the Weddel Sea and simple theories of bottom-water formation (Gill, 1973.
[Show full text]
The Ocean Floor Word Find Activity
The Ocean Floor Word Find Activity Beneath the ocean is a landscape, which has similar features to what we see on land. The ocean floor is generally divided into the continental shelf, the continental slope and the deep ocean floor. The land from the continent or an island gently extends out underneath the water to form a large area called the continental shelf. The continental shelf is a very important area under the ocean as a lot of marine life thrives there. The area can also contain petroleum, natural gas as well as minerals under the seafloor which are very valuable. The continental slope is the point where the shelf area plunges down into the deepest parts of the oceans. This part of the ocean floor is marked with deep canyons. Below the continental slopes sediment can often collect over time to form gental slopes called continental rises. The continental shelf, slope and rises are known as the continental margin. In many parts of the bottom of the ocean there are flat areas covered with sediment. This area is called the abyssal plain. The abyssal plain is usually found at depths between 3000 and 6000 metres below sea level. The abyssal plain is broken by mid ocean ridges, which are like long mountain ranges under the ocean. The entire global mid ocean ridge system is the longest mountain chain on earth and has formed where oceanic plates are continuously separating. These areas include the Mid-Atlantic ridge, the Pacific rise, as well as trenches such as the Marina Trench in the Pacific Ocean.
[Show full text]