Exploring Deep Oceanic Crust Off Hawai'i
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The Future of Continental Scientific Drilling U.S
THE FUTURE OF CONTINENTAL SCIENTIFIC DRILLING U.S. PERSPECTIVE Proceedings of a workshop | June 4-5, 2009 | Denver, Colorado DOSECC WORKSHOP PUBLICATION 1 Front Cover: Basalts and rhyolites of the Snake River Plain at Twin Falls, Idaho. Project Hotspot will explore the interaction of the Yellowstone hotspot with the continental crust by sampling the volcanic rocks underlying the plain. Two 1.5 km holes will penetrate both the surficial basalt and the underlying rhyolite caldera-fill and outflow depos- its. A separate drill hole will explore the paleoclimate record in Pliocene Lake Idaho in the western Snake River Plain. In addition to the understanding of continent-mantle interaction that develops and the paleoclimate data collected, the project will study water-rock interaction, gases emanating from the deeper curst, and the geomicro- biology of the rocks of the plain. Once scientific objectives and set, budgets are developed, and funding is granted, successful implementation of projects requires careful planning, professional on-site staff, appropriate equip- ment, effective logistics, and accurate accounting. Photo by Tony Walton The authors gratefully acknowledge support of the National Science Foundation (NSF EAR 0923056 to The University of Kansas) and DOSECC, Inc. of Salt Lake City, Utah. Anthony W. Walton, University of Kansas, Lawrence, Kansas Kenneth G. Miller, Rutgers University, New Brunswick, N.J. Christian Koeberl, University of Vienna, Vienna, Austria John Shervais, Utah State University, Logan, Utah Steve Colman, University of Minnesota, Duluth, Duluth, Minnesota edited by Cathy Evans. Stephen Hickman, US Geological Survey, Menlo Park, California covers and design by mitch favrow. Will Clyde, University of New Hampshire, Durham, New Hampshire document layout by Pam Lerow and Paula Courtney. -
IODP Deep Biosphere Research Workshop Report – a Synthesis of Recent Investigations, and Discussion of New Research Questions and Drilling Targets
Workshop White Papers Sci. Dril., 17, 61–66, 2014 www.sci-dril.net/17/61/2014/ doi:10.5194/sd-17-61-2014 Scientific Drilling © Author(s) 2014. CC Attribution 3.0 License. Open Access IODP Deep Biosphere Research Workshop report – a synthesis of recent investigations, and discussion of new research questions and drilling targets B. N. Orcutt1, D. E. LaRowe2, K. G. Lloyd3, H. Mills4, W. Orsi5, B. K. Reese6, J. Sauvage7, J. A. Huber8, and J. Amend2 1Bigelow Laboratory for Ocean Sciences, East Boothbay, ME 04544, USA 2University of Southern California, Los Angeles, CA 90089, USA 3University of Tennessee, Knoxville, TN 37996, USA 4University of Houston–Clear Lake, Houston, TX 77058, USA 5Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA 6University of Southern California, Los Angeles, CA 90089, USA 7Graduate School of Oceanography, University of Rhode Island, Narragensett, RI 02882, USA 8Marine Biological Laboratory, Woods Hole, MA 02543, USA Correspondence to: B. N. Orcutt ([email protected]) Received: 5 November 2013 – Revised: 30 December 2013 – Accepted: 7 February 2014 – Published: 29 April 2014 Abstract. During the past decade, the IODP (International Ocean Discovery Program) has fostered a sig- nificant increase in deep biosphere investigations in the marine sedimentary and crustal environments, and scientists are well-poised to continue this momentum into the next phase of the IODP. The goals of this work- shop were to evaluate recent findings in a global context, synthesize available biogeochemical data to foster thermodynamic and metabolic activity modeling and measurements, identify regional targets for future tar- geted sampling and dedicated expeditions, foster collaborations, and highlight the accomplishments of deep biosphere research within IODP. -
Mantle Hydration and Cl-Rich Fluids in the Subduction Forearc Bruno Reynard1,2
Reynard Progress in Earth and Planetary Science (2016) 3:9 Progress in Earth and DOI 10.1186/s40645-016-0090-9 Planetary Science REVIEW Open Access Mantle hydration and Cl-rich fluids in the subduction forearc Bruno Reynard1,2 Abstract In the forearc region, aqueous fluids are released from the subducting slab at a rate depending on its thermal state. Escaping fluids tend to rise vertically unless they meet permeability barriers such as the deformed plate interface or the Moho of the overriding plate. Channeling of fluids along the plate interface and Moho may result in fluid overpressure in the oceanic crust, precipitation of quartz from fluids, and low Poisson ratio areas associated with tremors. Above the subducting plate, the forearc mantle wedge is the place of intense reactions between dehydration fluids from the subducting slab and ultramafic rocks leading to extensive serpentinization. The plate interface is mechanically decoupled, most likely in relation to serpentinization, thereby isolating the forearc mantle wedge from convection as a cold, potentially serpentinized and buoyant, body. Geophysical studies are unique probes to the interactions between fluids and rocks in the forearc mantle, and experimental constrains on rock properties allow inferring fluid migration and fluid-rock reactions from geophysical data. Seismic velocities reveal a high degree of serpentinization of the forearc mantle in hot subduction zones, and little serpentinization in the coldest subduction zones because the warmer the subduction zone, the higher the amount of water released by dehydration of hydrothermally altered oceanic lithosphere. Interpretation of seismic data from petrophysical constrain is limited by complex effects due to anisotropy that needs to be assessed both in the analysis and interpretation of seismic data. -
Physiography of the Seafloor Hypsometric Curve for Earth’S Solid Surface
OCN 201 Physiography of the Seafloor Hypsometric Curve for Earth’s solid surface Note histogram Hypsometric curve of Earth shows two modes. Hypsometric curve of Venus shows only one! Why? Ocean Depth vs. Height of the Land Why do we have dry land? • Solid surface of Earth is Hypsometric curve dominated by two levels: – Land with a mean elevation of +840 m = 0.5 mi. (29% of Earth surface area). – Ocean floor with mean depth of -3800 m = 2.4 mi. (71% of Earth surface area). If Earth were smooth, depth of oceans would be 2450 m = 1.5 mi. over the entire globe! Origin of Continents and Oceans • Crust is formed by differentiation from mantle. • A small fraction of mantle melts. • Melt has a different composition from mantle. • Melt rises to form crust, of two types: 1) Oceanic 2) Continental Two Types of Crust on Earth • Oceanic Crust – About 6 km thick – Density is 2.9 g/cm3 – Bulk composition: basalt (Hawaiian islands are made of basalt.) • Continental Crust – About 35 km thick – Density is 2.7 g/cm3 – Bulk composition: andesite Concept of Isostasy: I If I drop a several blocks of wood into a bucket of water, which block will float higher? A. A thick block made of dense wood (koa or oak) B. A thin block made of light wood (balsa or pine) C. A thick block made of light wood (balsa or pine) D. A thin block made of dense wood (koa or oak) Concept of Isostasy: II • Derived from Greek: – Iso equal – Stasia standing • Density and thickness of a body determine how high it will float (and how deep it will sink). -
The Nature of the Mohorovicic Discontinuity, a Compromise 1
JOURNAL OF GEOPHYSICAL RESEARCH VOL. 68, No. 15 AUGUST 1, 1963 The Nature of the Mohorovicic Discontinuity, A Compromise 1 PETER J. WYLLIE Department of Geochemistry and Minemlogy Pennsylvania State Universit.y, University Park Abstract available . The experimental data and steady-state calculations make it difficult M to explain the discontinuity beneath both oceans and continents on the basis of the same change. The phase oceanic M discontinuity may be a chemical discontinuity between basalt and peridotite , and a similar chemical discontinuity ma,y thus be expected b�neath the conti nents. Since ayailable experimental data place the basalt-eclogite phase change at about thE' same depth as the continental M discontinuity, intersections may exist between a zone of chemical discontinuity and a phase transition zone, the transition being either basalt-ecloO"ite or feldspathic peridotite-garnet peridotite. Detection of the latter transition by seismic t�'h niques ma,y be difficult. The M discontinuity could therefore represent the basalt-eclogite phase change in some localities (e.g. mountain belts) and the chemical discontinuity in others (e.g. oceans and continental shields). Variations in the depth to the chemical discontinuity and in the positions of geoisotherms produce great flexibility in oro genetic models. Interse; tions between the two zones at depth could be reflected at the surface by major fault zones separating large structural blocks of different elevations. Chemical discontinuity. The conyentional termediate between dunite and basalt is view that the Moho discontinuity at the base of qualitatively reasonable for the mantle. the crust is caused by a chemical change from Ringwood [1962a, c] adopted a specific model basaltic rock to peridotite has been expounded compounded from the concepts advanced and recently by Hess [1955], Wager [1958], and developed by many petrologists and geochem Harris and Rowell [1960]. -
Density of Oceanic Crust
Density of Oceanic Crust Introduction Procedures Certain properties of a substance are both distinctive and Part 1 relatively easy to determine. Density, the ratio between 1. Complete Report Sheet 1 by calculating the missing a sample’s mass and volume at a specific temperature densities. How will you deal with the differences in and pressure (like standard ambient temperature and significant digits? Make sure to include units in your pressure), is one such property. Regardless of the size of a answers. sample, the density of a substance will always remain the 2. Using the depths and densities from your chart, plot same. The density of a rock sample can, therefore, be used a graph on your own paper (or use an electronic in the identification process. graphing tool) and title it Depth vs. Density. Hint: Think about independent and dependent variables. Using a While density may vary only slightly from rock to rock, blue colored pencil, draw a line of best fit from the XY- detailed sampling and correlation with other factors like intercept through the plotted points. depth may reveal important information about the history of a core, or may help to improve the use of seismic Part 2 profiles. The average density of oceanic crust is 3.0 g/cm3, 1. Find the mass and volume for each of the four continental while continental crust has an average of 2.7 g/cm3. samples as instructed by your teacher. How will you deal with error in the laboratory? How about significant Objectives digits? Record your answers in the space provided. -
Peter Castro | Michael E. Huber
TEACHER’S MANUAL Marine Science Peter Castro | Michael E. Huber SECOND EDITION Waves and Tides Chapter Introduce the BIG IDEA Waves and Tides Have students watch a short video clip of ocean waves 4 breaking on the shore. Have them make observations about the movement of water as the wave breaks and then retreats back to the ocean. If any students have been to the ocean, have them share their experience of the water and the waves. Pose students these questions and let them discuss responses in small groups. 1. Why does the size of a wave change as it approaches the shore? 2. What factors affect the tides and make the tide come in and leave again? 3. What hardships do marine organisms deal with that live in the intertidal zones? Small groups can share back with the whole group on key GO ONLINE To access points their groups discussed. inquiry and investigative activities to accompany this chapter. Ocean Section Pacing Main Idea and Key Questions Literacy Labs and Activities Standards 4.1 Introduc- 1 day Waves carry energy across the sea surface but Key Questions Activity: tion to Wave do not transport water. Making Waves Energy and 1. What are the three most common generating Motion forces of waves? 2. What are the two restoring forces that cause the water surface to return to its undisturbed state? 4.2 Types of 2 days There are several types of waves, each with its 2.d, 5.j, 6.f, Laboratory Manual: Making Waves own characteristics and different ways of 7.e Waves (p. -
Global Sea Level Rise Scenarios for the United States National Climate Assessment
Global Sea Level Rise Scenarios for the United States National Climate Assessment December 6, 2012 PhotoPhPhototo prpprovidedrovovidideedd bbyy thtthehe GrGGreaterreaeateter LaLLafourcheafofoururchche PoPortrt CoComommissionmimissssioion NOAA Technical Report OAR CPO-1 GLOBAL SEA LEVEL RISE SCENARIOS FOR THE UNITED STATES NATIONAL CLIMATE ASSESSMENT Climate Program Office (CPO) Silver Spring, MD Climate Program Office Silver Spring, MD December 2012 UNITED STATES NATIONAL OCEANIC AND Office of Oceanic and DEPARTMENT OF COMMERCE ATMOSPHERIC ADMINISTRATION Atmospheric Research Dr. Rebecca Blank Dr. Jane Lubchenco Dr. Robert Dietrick Acting Secretary Undersecretary for Oceans and Assistant Administrator Atmospheres NOTICE from NOAA Mention of a commercial company or product does not constitute an endorsement by NOAA/OAR. Use of information from this publication concerning proprietary products or the tests of such products for publicity or advertising purposes is not authorized. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the National Oceanic and Atmospheric Administration. Report Team Authors Adam Parris, Lead, National Oceanic and Atmospheric Administration Peter Bromirski, Scripps Institution of Oceanography Virginia Burkett, United States Geological Survey Dan Cayan, Scripps Institution of Oceanography and United States Geological Survey Mary Culver, National Oceanic and Atmospheric Administration John Hall, Department of Defense -
The Thrill to Drill
INTERNATIONAL CONTINENTAL SCIENTIFIC DRILLING PROGRAM The Thrill to Drill After more than two decades of International Continental Scientific Drilling: A prospect for the future As most of the Earth under our feet is inaccessible, drilling is the only ground truth to correct our models and ideas about our planet's interior. Drilling does not necessarily have to be done from the surface. Here, researchers follow the drilling progress while drilling boreholes in the Moab Khotsong gold mine (South Africa) in 3 kilometers depth. The project drilled several boreholes into and around seismogenic zones to study the rupture details and scaling of small and larger earthquakes. 2 The International Continental Scientific Drilling Program – an introduction For most people, drilling into the Earth means laying the foundation for extracting natural resources from under our feet. Indeed the vast majority of all drill rigs in the world are used either for establishing water wells or for the discovery and exploitation of mineral resources or hydrocarbons like oil and gas. There is, however, another aspect of drill- ing into the Earth’s crust of which only very few people are aware. Poking a hole into the skin of our planet can help sci- entists solve some of the many mysteries which remain hidden in its vast interior. During the past one and a half centu- ries geoscientists have made enormous strides in exploring the interior of the Earth indirectly by analyzing the chem- ical composition of lava from hundreds of volcanoes or by modeling the physical conditions at depth based on the inter- pretation of seismic waves. -
Drilling the Crust at Mid-Ocean Ridges
or collective redistirbution of any portion of this article by photocopy machine, reposting, or other means is permitted only with the approval of Th e Oceanography Society. Send all correspondence to: [email protected] or Th eOceanography PO Box 1931, Rockville, USA.Society, MD 20849-1931, or e to: [email protected] Oceanography correspondence all Society. Send of Th approval portionthe ofwith any articlepermitted only photocopy by is of machine, reposting, this means or collective or other redistirbution articleis has been published in Th SPECIAL ISSUE FEATURE Oceanography Drilling the Crust Threproduction, Republication, systemmatic research. for this and teaching article copy to use in reserved. e is rights granted All OceanographyPermission Society. by 2007 eCopyright Oceanography Society. journal of Th 20, Number 1, a quarterly , Volume at Mid-Ocean Ridges An “in Depth” perspective BY BENOÎT ILDEFONSE, PETER A. RONA, AND DONNA BLACKMAN In April 1961, 13.5 m of basalts were drilled off Guadalupe In the early 1970s, almost 15 years after the fi rst Mohole Island about 240 km west of Mexico’s Baja California, to- attempt, attendees of a Penrose fi eld conference (Confer- gether with a few hundred meters of Miocene sediments, in ence Participants, 1972) formulated the concept of a layered about 3500 m of water. This fi rst-time exploit, reported by oceanic crust composed of lavas, underlain by sheeted dikes, John Steinbeck for Life magazine, aimed to be the test phase then gabbros (corresponding to the seismic layers 2A, 2B, for the considerably more ambitious Mohole project, whose and 3, respectively), which themselves overlay mantle perido- objective was to drill through the oceanic crust down to tites. -
Global Geodynamic Cycles and Earth Evolution
Int J Earth Sci (Geol Rundsch) DOI 10.1007/s00531-014-1073-y ORIGINAL PAPER Drilling the solid earth: global geodynamic cycles and earth evolution John W. Shervais · Nicholas Arndt · Kathryn M. Goodenough Received: 17 March 2014 / Accepted: 24 August 2014 © The Author(s) 2014. This article is published with open access at Springerlink.com Abstract The physical and chemical evolution of the study global geodynamic processes, review past successes Earth is driven by geodynamic cycles that are global in in this realm that were sponsored in part by ICDP, and sug- scale, operating over 4.57 Ga of Earth’s history. Some pro- gest potential new targets for drilling campaigns that focus cesses are truly cyclic, e.g., the Wilson Cycle, while oth- on solid earth evolution. This paper builds on discussions at ers are irreversible (e.g., core formation). Heat and mass the 2013 ICDP Science Meeting on the future of continen- transfer between the lowermost mantle (e.g., core-mantle tal scientific drilling, held in Potsdam in November 2013. boundary) and the surface drives these global geodynamic processes. Subduction of lithospheric plates transfers cool Keywords Global geodynamics · Plate tectonics · fractionated material into the lower mantle and leads indi- Continental scientific drilling · Heat and mass transfer rectly to the formation of new oceanic lithosphere, while the rise of thermochemical plumes recycles the remnants of these plates back to the surface, driven by heat transfer Introduction across the core–mantle boundary. These global geodynamic cycles are responsible for hotspot volcanism, the formation The geodynamic evolution of Earth began shortly after of continental crust, collisional orogenies, continental rift- accretion at 4.57 Ga and continues today. -
Cretaceous History of Pacific Basin Guyot Reefs: a Reappraisal Based on Geothermal Endo-Upwelling
PALAEOZ1c01061 ELSEVIER Palaeogeography, Palaeoclimatology, Palaeoecology 112 (1994) 239-260 Cretaceous history of Pacific Basin guyot reefs: a reappraisal based on geothermal endo-upwelling Francis Rougerie a, J.A. Fagerstrom a QRSTQM, B. P. 529, Papeete, Tahiti, French Polynesia Departinent of GeologicalSciences, The Uiziversity of Colorado, Boulder, CO 80309, USA Received 23 July, 1992; revised and accepted 15 April 1994 Abstract The mid-Cretaceous histories (origin, growth, death) of algal-rudist-stromatoporoid reef communities located on many Pacific Basin guyots are complex and controversial. These shallow water, tropical communities originated on volcanic edifices extruded during the Barremian-Albian, grew upward during edifice subsidenceftransgression throughout the Aptian, Albian and Cenomanian and several of them died almost synchronously near the Cenomanian- Turonian boundary. During their periods of origin and growth, we postulate that the reef ecosystems received dissolved oxygen by wave surge and nutrients by geothermal endo-upwelling. By this process oceanic waters of intermediate depth (approx. 500-1500 m) were: (a) drawn into the weathered and fractured volcanic summit and lower part of the older reef and driven upward through the porous framework by the remnant geothermal gradient of the volcanic foundation and (b) emerged at the reef surface to support the high metabolism of the living community. The death of most of the reefs near the Cenomanian-Turonian boundary approximately coincides with the most intense oceanic anoxic event (Om)in Pacific Ocean history. During this OAE the chemistry of the endo-upwelled fluids arriving at the reef surface changed from nutrient/oxygen-rich to dysoxic-anoxic-toxic, and killed the community.