DOCSLIB.ORG

Thickness Distribution of Reddish Brown Clay in the Western North Pacific*

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Thickness Distribution of Reddish Brown Clay in the Western North Pacific* Journal of the Oceanographical Society of Japan Vol.43, pp.139 to 148, 1987 Thickness Distribution of Reddish Brown Clay in the Western North Pacific* Satoshi Yamamotot Abstract: Thickness and stratigraphy of reddish brown clay were compiled from lithologic descriptions of various types of cored surface sediments in the western North Pacific. Thin brown clays usually overlie gray clay in hemipelagic deposi- tional environments and the thickness of the brown clay increases offshore, as results of the decreasing rate of sedimentation of terrigenous organic matter. The hemipelagic gray clay disappears in pelagic environments and several tens of meters of pelagic red clay overlies the basement sedimentary sequences of bedded chert and chalk in the pelagic seafloor. In the boundary region of the hemipelagic and pelagic sequences at the outer open floor of the trench basin, the pelagic facies of the red clay-bedded chert-chalk assemblage underlie the hemipelagic gray clay. This stratigraphy might indicate subduction of pelagic facies below the hemipelagic sequences. 1. Introduction pelagic reddish clay; what underlies the hemi- Since the scientific expedition of H. M. S. pelagic grayish clay or the pelagic reddish clay; Challenger, it has been recognized that two types etc. All these questions are concerned with the of clays of reddish brown and greenish gray genesis and sedimentary processes of these grayish (bluish) are distributed very widely in the world and brownish clays in the ocean. Although an ocean (Murray and Hjort, 1912). The reddish isopach map of the brown clay in hemipelagic brown clays are commonly observed in the open environments was published for the marginal sea, whereas the greenish gray clays are found areas of the eastern Pacific Ocean (Lyle, 1983), in the continental margin area. However, the the same kind of map for the continental margin stratigraphic features of these two types of clays in the western North Pacific has not yet been in the ocean floor still require study. Numerous constructed. Masuzawa (1983) has investigated coring operations on the ocean floor have re- the relatidnship between water depth and the vealed that a few centimeters of brown clay thickness of the oxidized brown clay in the Japan usually overlies gray mud in hemipelagic environ- Sea by compiling lithologic data on sediment- ments (Lynn and Ponatti, 1965; Lyle, 1983). cores from many cruise reports of R/V Haku- The color difference between the reddish brown ho Maru, Hakurei Maru, Vema and Conrad; and greenish gray sediments can be explained however, the geographical distribution of thick- as results of oxidation and reduction of iron (Fe) ness of the oxidized brown clay was not shown and manganese (Mn) products in the sediment, by his study. so that the brown-gray transition boundary in The present report is intended to construct the hemipelagic sediment can be interpreted as an isopach map of the oxidized brown clay on a redox transitional zone (Lyle, 1983). the grayish clay in the marginal area' of the The question arises, however; whether or not Japanese Islands, by compiling lithologic descrip- the brown-gray redox boundary can be observed tions on sediment-cores from several cruise re- in the pelagic deposits of reddish clay; how ports of R/V Hakuho Maru, Hakurei Maru, thick is the hemipelagic grayish clay or the and D/V Glomar Challenger, and other scientific * Received 9 January 1987; in revised form 14 reports available to the author. Stratigraphic May 1987; accepted 23 May 1987. features of the hemipelagic sediments and pelagic † Department of Oceanography, Ryukyu University, red clay are summarized here from the lithologic Nishihara, Okinawa 903-01. data to investigate the genesis of these sedi- 140 Yamamoto Fig. 1. Bathymetry and sampling sites for surface cores in the western North Pacific. Sampling sites are labeled and shown by various symbols in legend: 1; Hakurei Maru sites (labeling number indicates site designation). 2; Hakuho Maru site (cruise number). 3; Tansei Maru site (cruise number). 4; Nagasaki Maru site (cruise number). Major bathymetric contours are in km. ments in the ocean. The compiled region is cruise reports) mainly restricted to the North Pacific region. (2) Cruise reports by the Geological Survey of Japan (G. S. J.); 2. Information source and data analysis No.4, No.5, No.6, No.7, No.8, No.9, The lithology and thickness of sediments were No.10, No.11, No.12, No.13, No.14, judged from the lithologic descriptions of core- No.15, No.17, No.18, No.19, No.20. samples recovered during scientific cruises. The (3) Initial reports of the Deep Sea Drilling lithologic information includes color and grain Project (DSDP); size (e. g. clay, silt, mud, sand, gravel, etc.) of Vol.5, Vol.6, Vol.7, Vol.9, Vol.16, sediments. The compiled scientific reports are: Vol.17, Vol.18, Vol.19, Vol.20, Vol.31, (1) Preliminary reports of Hakuho Maru Vol.32, Vol,33, Vol.55, Vol.56, Vol.57, cruises; Vol.58, Vol.59, Vol.61, Vol.62, Vol.63, KH68-3, KH68-4, KH69-2, KH71-1, KH71-5, Vol.85, Vol.86, Vol.87, and Newsletter on KH72-2, KH75-3, KH77-1, KH77-3, KH78-3, Leg 89. KH79-3*, KH80-1*, KH80-3, KH81-3*, For the oceans surrounding the Ryukyu Islands, KH82-4, KH84-1, KH86-1.(* unpublished the data were also compiled from the unpublished Thickness Distribution of Reddish Brown Clay in the Western North Pacific 141 Fig. 2. Isopach map of oxidized brown clay in the western North Pacific. Isopach contours are in cm. Areas with thicknesses larger than 500cm are hatched by lines. Trench axis is shown by dashed line. reports of RN cruises (Ryukyu University and hues with very low chroma and intermediate Nagasaki University joint educational cruises) lightness, or hues 5GY and 10GY)-including by R/V Nagasaki Maru (Yamamoto et al., 1984) greenish gray, dark gray, and brownish gray. and KT84-14 cruise by R/V Tansei Maru (Ono Black mud was not a dominant lithology for et al., 1987). The compiled data include 247 oceanic sediments, as far as the present data piston cores, 62 box cores, 153 grab sampler's compilation was concerned. Whitish mud was cores, and 10 Smith-McIntyre sampler, gravity, often considered as calcareous ooze, in which and other similar kinds of cores covering the CaCO3 content is more than about 80%, for entire Pacific region. oceanic sediments. There might exist a brown- Colors in lithologic descriptions of clayey sedi- gray redox boundary in the calcareous ooze as ments, which were followed descriptions in the a very obvious color contact. However, the published reports, are grouped into two essential analysis for lithologic colors was restricted to types; (1) reddish brown (hues 5R, 10R, 5YR, clayey sediments in which CaCO3 may be less 10YR, 5Y and 10Y, excluding too low lightness than about 50%. The colors of sands can be and too low values of chroma: Rock-Color Chart, also grouped into gray and reddish brown types; Geological Society of America) - including however, the sand-dominated sediments as mas- such colors as brown, yellowish brown, dark sive beds are restricted to the continental shelf brown, and pinkish brown; and (2) gray (any areas (Boggs, 1984). 142 Yamamoto Thickness (cm) of brown mud overlying on gray mud Leg end (Total 141 points) Fig. 3. Relationship between thickness of brown mud overlying gray mud and water depth. The color change from reddish brown to the ever, the type of contact was not compiled in greenish gray muds can be considered as the this study, because many descriptions did not change of oxidized to reduced states. Although describe the contacts precisely. There are a few the exact match of the oxidation-reduction con- cases in which the brownish and grayish muds ditions to colors was not clearly demonstrated were deposited cyclically with approximate thick- by chemical measurements (Pantin, 1969; Lyle, ness of 100 cm for each bed. In this case, how- 1983), the essential mechanism to cause the ever, the lithology changed cyclically to the color change can be considered as oxidation- underlying unit's lithology of grayish mud. The reduction of various Fe products contained in boundary in this kind of transitional zone was the sediment (Heller-Kallai and Rozenson, 1978; determined arbitrarily judging from the lithologic Rozenson and Heller-Kallai, 1978). descriptions. Data for thickness of the reddish brown mud on the gray mud were compiled from the litho- 3. Thickness distribution of oxidized brown logic descriptions. The contact between the clay on gray clay reddish brown and grayish muds was of various Figure 1 shows the site locations of the cores types; sharp, gradual, and gradational. How- used to construct the isopach map of the brown Thickness Distribution of Reddish Brown Clay in the Western North Pacific 143 A Fig. 4. Bathymetry and sites for surface cores and thickness (cm) of brown clay in the Pacific. Area A is illustrated in Fgs. 1 and 2. Area GH is represented by numerous (more than 200) surface cores of brown clays which did not reach to the base within sampler's depth (<5 m), based on Hakurei Maru sampling sites. Other sites were sampled by Hakuho Maru, and their labels indicate recovered thickness (cm) of reddish brown clay. Bathymetric contours are in km. clay overlying gray sediments in the adjacent of the regional differences of basins. The thick- seafloors of the Japanese Islands. The contoured ness of the brown clay in the trench basins of map for the thickness of brown clay is shown greatest water depths is not as much as that in in Fig. 2, which indicates that the marginal the open seafloors, since the distance to the area of the islands is covered by gray sand and trench floors from the islands is shorter than mud without brown clay (thickness is 0 cm) and that to the open seafloors.
Load more

Recommended publications
  • Petrology, Sedimentology, and Diagenesis of Hemipelagic Limestone and Tuffaeeous Turbidites in the Aksitero Formation, Central Luzon, Philippines
    Petrology, Sedimentology, and Diagenesis of Hemipelagic Limestone and Tuffaeeous Turbidites in the Aksitero Formation, Central Luzon, Philippines Prepared in cooperation with the Bureau of Mines, Republic of the Philippines, and the U.S. National Science Foundation Petrology, Sedimentology, and Diagenesis of Hemipelagic Limestone and Tuffaceous Turbidites in the Aksitero Formation, Central Luzon, Philippines By ROBERT E. GARRISON, ERNESTO ESPIRITU, LAWRENCE J. HORAN, and LAWRENCE E. MACK GEOLOGICAL SURVEY PROFESSIONAL PAPER 1112 Prepared in cooperation with the Bureau of Mines, Republic of the Philippines, and the U.S. National Science Foundation UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1979 UNITED STATES DEPARTMENT OF THE INTERIOR CECIL D. ANDRUS, Secretary GEOLOGICAL SURVEY H. William Menard, Director United States. Geological Survey. Petrology, sedimentology, and diagenesis of hemipelagic limestone and tuffaceous turbidites in the Aksitero Formation, central Luzon, Philippines. (Geological Survey Professional Paper; 1112) Bibliography: p. 15-16 Supt. of Docs. No.: 119.16:1112 1. Limestone-Philippine Islands-Luzon. 2. Turbidites-Philippine Islands-Luzon. 3. Geology, Stratigraphic-Eocene. 4. Geology, Stratigraphic-Oligocene. 5. Geology-Philippine Islands-­ Luzon. I. Garrison, Robert E. II. United States. Bureau of Mines. III. Philippines (Republic) IV. United States. National Science Foundation. V. Title. VI. Series: United States. Geological Survey. Professional Paper; 1112. QE471.15.L5U54 1979 552'.5 79-607993 For sale
    [Show full text]
  • A Detailed Study of the Physical Properties of Recently
    A DETAILED STUDY OF THE PHYSICAL PROPERTIES OF RECENTLY DEPOSITED SEDIMENTS FROM A MINIBASIN, NORTHWEST GULF OF MEXICO A Thesis by MARCO ANTONIO SANTOS CASTANEDA Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE May 2012 Major Subject: Oceanography A DETAILED STUDY OF THE PHYSICAL PROPERTIES OF RECENTLY DEPOSITED SEDIMENTS FROM A MINIBASIN, NORTHWEST GULF OF MEXICO A Thesis by MARCO ANTONIO SANTOS CASTANEDA Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Approved by: Co-Chairs of Committee, Niall Slowey William Bryant Committee Member, Zenon Medina-Cetina Head of Department, Piers Chapman May 2012 Major Subject: Oceanography iii ABSTRACT A Detailed Study of the Physical Properties of Recently Deposited Sediments from a Minibasin, Northwest Gulf of Mexico. (May 2012) Marco Antonio Santos Castaneda, B.S., Universidad Naval Comandante Rafael Moran Valverde Co-Chairs of Advisory Committee: Dr. Niall Slowey Dr. William Bryant High-resolution seismic data from lower slope basins in the vicinity of Bryant and Keathley Canyons suggest the recent occurrence of thin mud flow events which influence the physical properties of the shallow sediments of the minibasin. Therefore to understand the effect of these events on the physical properties, a very high spatial resolution investigation of the following properties was undertaken: bulk density, grain density, shear strength, water content, ―calcium carbonate‖ content, compressional wave velocity, and the relative elemental composition, of the first 5 meters of the seabed sediments.
    [Show full text]
  • Depositional Processes and Environments in Wolfcampian-Leonardian Strata, Southern Midland Basin, Texas
    DEPOSITIONAL PROCESSES AND ENVIRONMENTS IN WOLFCAMPIAN-LEONARDIAN STRATA, SOUTHERN MIDLAND BASIN, TEXAS By ZAKORY DEAN WARD Bachelor of Science in Geology Iowa State University Ames, Iowa 2013 Submitted to the Faculty of the Graduate College of the Oklahoma State University in partial fulfillment of the requirements for the Degree of MASTER OF SCIENCE May, 2017 DEPOSITIONAL PROCESSES AND ENVIRONMENTS IN WOLFCAMPIAN-LEONARDIAN STRATA, SOUTHERN MIDLAND BASIN, TEXAS Thesis Approved: Dr. Jack C. Pashin Thesis Advisor Dr. Jim Puckette Dr. Mary Hileman ii ACKNOWLEDGEMENTS Foremost, I would like to thank my advisor, Dr. Jack Pashin, for his guidance, insight, and support throughout the course of this research. Additionally, thank you to my committee members, Dr. Jim Puckette and Dr. Mary Hileman, for their guidance and support over the last few years. I would like to give thanks to my colleagues and the department faculty and staff for making my time at Oklahoma State University a great experience. Special thanks to my family and friends for their continued support throughout my academic career. Finally, I would like to thank EOG Resources for their support. This study would not have been possible without support from EOG Resources, who funded this research and provided the core and associated data. iii Acknowledgements reflect the views of the author and are not endorsed by committee members or Oklahoma State University. Name: ZAKORY DEAN WARD Date of Degree: MAY, 2017 Title of Study: DEPOSITIONAL PROCESSES AND ENVIRONMENTS IN WOLFCAMPIAN-LEONARDIAN STRATA, SOUTHERN MIDLAND BASIN, TEXAS Major Field: GEOLOGY Abstract: The Early Permian (Wolfcampian-Leonardian) Wolfcamp interval of the Permian Basin in West Texas is a mixed siliciclastic-carbonate succession that hosts one of the most important unconventional oil and gas plays in the world.
    [Show full text]
  • Emelyan M. Emelyanov the Barrier Zones in the Ocean 3540253912-Prelims I XX.Qxd 6/1/05 12:49 PM Page Iii
    3540253912-Prelims_I_XX.qxd 6/1/05 12:49 PM Page i Emelyan M. Emelyanov The Barrier Zones in the Ocean 3540253912-Prelims_I_XX.qxd 6/1/05 12:49 PM Page iii Emelyan M. Emelyanov The Barrier Zones in the Ocean Translated into English by L.D. Akulov, E.M. Emelyanov and I.O. Murdmaa With 245 Figures and 107 Tables 3540253912-Prelims_I_XX.qxd 6/1/05 12:49 PM Page iv Dr. Emelyan M. Emelyanov Research Professor in Marine Geology Prospekt Mira 1 Kaliningrad 236000 Russia E-mail: [email protected], [email protected] Translated into English by – Leonid D. Akulov, Emelyan M. Emelyanov, Ivar O. Murdmaa (specific geological terminology) The book was originally published in Russian under the title “The barrier zones in the ocean. Sedimentation, ore formation, geoe- cology”. Yantarny Skaz, Kaliningrad, 1998, 416 p. (with some new chapters, Tables and Figures) Library of Congress Control Number: 2005922606 ISBN-10 3-540-25391-2 Springer Berlin Heidelberg New York ISBN-13 978-3-540-25391-4 Springer Berlin Heidelberg New York This work is subject to copyright. All rights are reserved, whether the whole or part of the mate- rial is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recita- tion, broadcasting, reproduction on microfilm or in any other way, and storage in data banks. Duplication of this publication or parts thereof is permitted only under the provisions of the German Copyright Law of September 9, 1965, in its current version, and permission for use must always be obtained from Springer-Verlag. Violations are liable to prosecution under the German Copyright Law.
    [Show full text]
  • 1. Cenozoic and Mesozoic Sediments from the Pigafetta Basin, Leg
    Larson, R. L., Lancelot, Y., et al., 1992 Proceedings of the Ocean Drilling Program, Scientific Results, Vol. 129 1. CENOZOIC AND MESOZOIC SEDIMENTS FROM THE PIGAFETTA BASIN, LEG 129, SITES 800 AND 801: MINERALOGICAL AND GEOCHEMICAL TRENDS OF THE DEPOSITS OVERLYING THE OLDEST OCEANIC CRUST1 Anne Marie Karpoff2 ABSTRACT Sites 800 and 801 in the Pigafetta Basin allow the sedimentary history over the oldest remaining Pacific oceanic crust to be established. Six major deposition stages and events are defined by the main lithologic units from both sites. Mineralogical and chemical investigations were run on a large set of samples from these units. The data enable the evolution of the sediments and their depositional environments to be characterized in relation to the paleolatitudinal motion of the sites. The upper part of the basaltic crust at Site 801 displays a complex hydrothermal and alteration evolution expressed particularly by an ochre siliceous deposit comparable to that found in the Cyprus ophiolite. The oldest sedimentary cover at Site 801 was formed during the Callovian-Bathonian (stage 1) with red basal siliceous and metalliferous sediments similar to those found in supraophiolite sequences, and formed near an active ridge axis in an open ocean. Biosiliceous sedimentation prevailed throughout the Oxfordian to Campanian, with rare incursions of calcareous input during the middle Cretaceous (stages 2, 4, and 5). The biosiliceous sedimentation was drastically interrupted during the Aptian-Albian by thick volcaniclastic turbidite deposits (stage 3). The volcanogenic phases are pervasively altered and the successive secondary mineral parageneses (with smectites, celadonite, clinoptilolite, phillipsite, analcime, calcite, and quartz) define a "mineral stratigraphy" within these deposits.
    [Show full text]
  • Deep Sea Drilling Project Initial Reports Volume 5
    30. LITHOLOGIC SUMMARY Oscar E. Weser, Chevron Oil Field Research Company, La Habra, California INTRODUCTION Using this added distinction, one can account for the seeming contradiction that some pelagic sediments A broad spectrum of terrigenous and pelagic sedi- had a higher sedimentation rate than some terrigenous ments was encountered on Leg 5. The terrigenous sediments. The former contained significant amounts sediments occur only in those sites drilled closest to (up to 95 per cent) of siliceous and/or calcareous tests land masses. The more distant drill sites penetrated of planktonic microorganisms. It is obvious that when pelagic sediments. Pelagic deposits were also found in employing a system of dividing sediments into pelagic two nearshore sites at Holes 32 and 36. The distribu- and terrigenous deposits based on the rate continental tion of these two classes of sediment for the Leg 5 detritus accumulates, the products of plankton pro- drill sites is shown on Figure 1. duction act as a biasing diluent. By compensating for the biogenous constituents, one can generalize that Of the 1808 meters1 of sediment penetrated on Leg 5, most terrigenous sediments found on Leg 5 did have a 1344 meters (75 per cent) are terrigenous2 and 464 higher sedimentation rate than the pelagic sediments. meters (25 per cent) are pelagic. Table 1 lists the sedimentary constituents encountered In this inquiry, the main criterion used to differentiate in the terrigenous and pelagic deposits of the various pelagic from terrigenous deposits was color: pelagic holes on Leg 5. This table includes only those con- sediments typically were red, brown or yellow; green, stituents which were recognized while making visual blue and black characterized the terrigenous sediments.
    [Show full text]
  • Gaps Than Shale: Erosion of Mud and Its Effect on Preserved Geochemical and Palaeobiological Signals
    Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021 More gaps than shale: erosion of mud and its effect on preserved geochemical and palaeobiological signals JOA˜ O TRABUCHO-ALEXANDRE Department of Earth Sciences, University of Durham, South Road, Durham DH1 3LE, UK (e-mail: [email protected]) Current address: Department of Earth Sciences, Utrecht University, Budapestlaan 4, 3584 CD Utrecht, The Netherlands Abstract: Ths wht th fn-grnd mrine sdmtry rcrd rlly lks like. Gold Open Access: This article is published under the terms of the CC-BY 3.0 license. It has been forty-one years since the publication Unlike in freshwater, mud in the marine envi- of the first edition of The Nature of the Stratigraph- ronment is mostly present as aggregates with set- ical Record by Derek Ager (1973). In his provoca- tling velocities and hydraulic behaviour that are tive book, Ager suggested that the sedimentary very different from those predicted for individual record is riddled with gaps, and that short, recurring particles by Stokes’s Law and the Shields and events may have had more effect on the rock record Hjulstro¨m–Sundborg diagrams. Fresh, aggregated than long periods of cumulative slow change by pro- mud deposits with up to 90% water by volume cesses operating at relatively constant rates. Ager’s have lower densities and shear strengths than non- catchphrase ‘more gaps than record’ is not normally aggregated mud deposits, and are therefore easier considered to be applicable to the marine fine- to erode than predicted by experimental curves. grained sedimentary record, which is commonly This paper focusses on the origin and strati- thought – or at least taught – to be virtually com- graphic nature of stratification surfaces in shales.
    [Show full text]
  • 30. Gravitational Compaction Patterns Determined from Sediment Cores
    30. GRAVITATIONAL COMPACTION PATTERNS DETERMINED FROM SEDIMENT CORES RECOVERED DURING THE DEEP SEA DRILLING PROJECT LEG 67 GUATEMALAN TRANSECT: CONTINENTAL SLOPE, MIDDLE AMERICA TRENCH, AND COCOS PLATE1 Richard W. Faas, Department of Geology, Lafayette College, Easton, Pennsylvania ABSTRACT A transect down the Guatemalan continental slope, across the Middle America Trench, and onto the Cocos Plate re- veals significantly different conditions of sediment compaction. Factors responsible for these compaction states are (1) lithologic variation, (2) variable rates of lithostatic loading, (3) lateral and vertical tectonics, and (4) generation of gases through biochemical processes and/or gas hydrate decomposition. In most cases, undercompaction appeared related to gas generation and rapid sedimentation rates, regardless of li- thology. Overcompaction appeared related to lithification (including diagenetic effects) and sedimentation rates. Conti- nental slope sediments showed predictable intervals of undercompaction, extending from 60 to about 200 meters below mudline, followed by overcompacted sediments to the base of the hole. Overcompaction throughout the entire sediment column at Holes 494 and 494A (Trench inner slope) may reflect lateral compressive stresses exerted by the subduction mechanism or removal of overburden. Trench sediments exhibit undercompaction at sub-bottom depths less than 75 meters, becoming normal to overcompacted between 100 and 200 meters. Gas generation within the Trench turbidites, combined with rapid sedimentation, is responsible for the shallow undercompacted unit. On the oceanic Plate, litho- logic changes, variable depositional rates, and vertical tectonics appear responsible for differing compaction states. INTRODUCTION from a transect across the Guatemalan continental slope, through the Middle America Trench, and onto the con- Gravitational compaction describes the process where- verging Cocos Plate (Fig.
    [Show full text]
  • Deep-Water Biogenic Sediment Off the Coast of Florida
    Deep-Water Biogenic Sediment off the Coast of Florida by Claudio L. Zuccarelli A Thesis Submitted to the Faculty of The Charles E. Schmidt College of Science In Partial Fulfillment of the Requirements for the Degree of Master of Science Florida Atlantic University Boca Raton, FL May 2017 Copyright 2017 by Claudio L. Zuccarelli ii Abstract Author: Claudio L. Zuccarelli Title: Deep-Water Biogenic Sediment off the Coast of Florida Institution: Florida Atlantic University Thesis Advisor: Dr. Anton Oleinik Degree: Master of Science Year: 2017 Biogenic “oozes” are pelagic sediments that are composed of > 30% carbonate microfossils and are estimated to cover about 50% of the ocean floor, which accounts for about 67% of calcium carbonate in oceanic surface sediments worldwide. These deposits exhibit diverse assemblages of planktonic microfossils and contribute significantly to the overall sediment supply and function of Florida’s deep-water regions. However, the composition and distribution of biogenic sediment deposits along these regions remains poorly documented. Seafloor surface sediments have been collected in situ via Johnson- Sea-Link I submersible along four of Florida’s deep-water regions during a joint research cruise between Harbor Branch Oceanographic Institute (HBOI) and Florida Atlantic University (FAU). Sedimentological analyses of the taxonomy, species diversity, and sedimentation dynamics reveal a complex interconnected development system of Florida’s deep-water habitats. Results disclose characteristic microfossil assemblages of planktonic foraminiferal ooze off the South West Florida Shelf, a foraminiferal-pteropod ooze through the Straits iv of Florida, and pteropod ooze deposits off Florida’s east coast. The distribution of the biogenic ooze deposits is attributed to factors such as oceanographic surface production, surface and bottom currents, off-bank transport, and deep-water sediment drifts.
    [Show full text]
  • Census of Seafloor Sediments in the World's Ocean
    Downloaded from geology.gsapubs.org on August 20, 2015 Census of seafloor sediments in the world’s ocean Adriana Dutkiewicz1, R. Dietmar Müller1, Simon O’Callaghan2, and Hjörtur Jónasson1 1EarthByte Group, School of Geosciences, University of Sydney, Sydney, NSW 2006, Australia 2National ICT Australia (NICTA), Australian Technology Park, Eveleigh, NSW 2015, Australia ABSTRACT and to overcome the shortcomings of inconsis- Knowing the patterns of distribution of sediments in the global ocean is critical for under- tent, poorly defined, and obsolete classification standing biogeochemical cycles and how deep-sea deposits respond to environmental change schemes and terminologies that are detailed in at the sea surface. We present the first digital map of seafloor lithologies based on descrip- the majority of cruise reports. Our goal is to ad- tions of nearly 14,500 samples from original cruise reports, interpolated using a support vec- here to the classification scheme currently used tor machine algorithm. We show that sediment distribution is more complex, with significant by the International Ocean Discovery Program deviations from earlier hand-drawn maps, and that major lithologies occur in drastically (Mazzullo et al., 1990), focusing on the descrip- different proportions globally. By coupling our digital map to oceanographic data sets, we tive aspect of the sediment rather than its genetic find that the global occurrence of biogenic oozes is strongly linked to specific ranges in sea- implications. As a result, we identify the follow- surface parameters. In particular, by using recent computations of diatom distributions from ing major classes of marine sediment (Fig. 1): pigment-calibrated chlorophyll-a satellite data, we show that, contrary to a widely held view, gravel, sand, silt, clay, calcareous ooze, radiolar- diatom oozes are not a reliable proxy for surface productivity.
    [Show full text]
  • 11. Depositional Facies of Leg 30, Deep Sea Drilling Project Sediment
    11. DEPOSITIONAL FACIES OF LEG 30 DEEP SEA DRILLING PROJECT SEDIMENT CORES George deVries Klein, Department of Geology, University of Illinois, Urbana, Illinois ABSTRACT Sediment cores from Leg 30 are subdivided into eight sedimentary facies. The vertical sequence of these facies is controlled by dif- ferences in tectonic setting from which the cores were obtained. Three sites (285, 286, 287) sampled marginal basins, whereas two sites (288, 289) were obtained from an equatorial plateau. The marginal basin facies at Sites 285 and 286 consist of basal sandy turbidites (facies 1) interbedded with mass flow and debris flow conglomerates (facies 2). Within the turbidite intervals, particu- larly at Site 286, an upward increase in flow intensity is suggested from the vertically upward increase in coarse-tail graded bedding which in turn is overlain by an interval of facies 2 conglomerates. Such coarsening-upward facies successions mimic the prograda- tional model of submarine fan evolution documented elsewhere. These clastic facies are overlain by biogenic ooze (some reworked by turbidity currents) of facies 3 and they in turn are capped by abyssal red clays (facies 4). At Site 287 in the Coral Sea Basin, the vertical facies succession consists of basal biogenic oozes (facies 3) overlain by olive clays (facies 6) and capped by silty and clayey turbidites (facies 5) organized into graded cycles. The two sites on the Ontong-Java Plateau show a different facies evolution from a basal facies consisting of reworked and mixed volcanic ash and biogenic sediments and chert (facies 8) to an upper facies consisting of biogenic ooze only (facies 7).
    [Show full text]
  • Challenges of Measuring Abyssal Temperature and Salinity at the Kuroshio Extension Observatory
    NOVEMBER 2020 A N D E R S O N E T A L . 1999 Challenges of Measuring Abyssal Temperature and Salinity at the Kuroshio Extension Observatory a,b c d NATHAN D. ANDERSON, KATHLEEN A. DONOHUE, MAKIO C. HONDA, b a,b MEGHAN F. CRONIN, AND DONGXIAO ZHANG a Cooperative Institute for Climate, Ocean, and Ecosystem Studies, University of Washington, Seattle, Washington; b NOAA/Pacific Marine Environment Laboratory, Seattle, Washington; c Graduate School of Oceanography, University of Rhode Island, Narragansett, Rhode Island; d Japan Agency for Marine-Earth Science and Technology, Yokosuka, Kanagawa, Japan (Manuscript received 9 September 2019, in final form 5 February 2020) ABSTRACT: The deep ocean is severely undersampled. Whereas shipboard measurements provide irregular spatial and temporal records, moored records establish deep ocean high-resolution time series, but only at limited locations. Here, highlights and challenges of measuring abyssal temperature and salinity on the Kuroshio Extension Observatory (KEO) mooring (32.38N, 144.68E) from 2013 to 2019 are described. Using alternating SeaBird 37-SMP instruments on annual deployments, an apparent fresh drift of 0.03–0.06 psu was observed, with each newly deployed sensor returning to historical norms near 34.685 psu. Recurrent salinity discontinuities were pronounced between the termination of each deployment and the initiation of the next, yet consistent pre- and postdeployment calibrations suggested the freshening was ‘‘real.’’ Because abyssal salinities do not vary by 0.03–0.06 psu between deployment locations, the contradictory salinities during mooring overlap pointed toward a sensor issue that self-corrects prior to postcalibration. A persistent nepheloid layer, unique to KEO and characterized by murky, sediment-filled water, is likely responsible for sediment accretion in the conductivity cell.
    [Show full text]