Contourites and Associated Sediments Controlled by Deep-Water » Crossmark Circulation Processes: State-Of-The-Art and Future Considerations
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Sediment Activity Answer Key
Sediment Activity Answer Key 1. Were your predictions close to where calcareous and siliceous oozes actually occur? Answers vary. 2. How does your map compare with the sediment distribution map? Answers vary. 3. Which type of ooze dominates the ocean sediments, calcareous or siliceous? Why? Calcareous sediments are formed from the remains of organisms like plankton with calcium-based skeletons1, such as foraminifera, while siliceous ooze is formed from the remains of organisms with silica-based skeletons like diatoms or radiolarians. Calcareous ooze dominates ocean sediments. Organisms with calcium-based shells such as foraminifera are abundant and widely distributed throughout the world’s ocean basins –more so than silica-based organisms. Silica-based phytoplankton such as diatoms are more limited in distribution by their (higher) nutrient requirements and temperature ranges. 4. What parts of the ocean do not have calcareous ooze? What might be some reasons for this? Remember that ooze forms when remains of organisms compose more than 30% of the sediment. The edges of ocean basins bordering land tend to have a greater abundance of lithogenous sediment –sediment that is brought into the ocean by water and wind. The proportion of lithogenous sediment decreases however as you move away from the continental shelf. In nutrient rich areas such as upwelling zones in the polar and equatorial regions, silica-based organisms such as diatoms or radiolarians will dominate, making the sediments more likely to be a siliceous-based ooze. Further, factors such as depth, temperature, and pressure can affect the ability of calcium carbonate to dissolve. Areas of the ocean that lie beneath the carbonate compensation depth (CCD), below which calcium carbonate dissolves, typically beneath 4-5 km, will be dominated by siliceous ooze because calcium-carbonate-based material would dissolve in these regions. -
Sediment Transport and the Genesis Flood — Case Studies Including the Hawkesbury Sandstone, Sydney
Sediment Transport and the Genesis Flood — Case Studies including the Hawkesbury Sandstone, Sydney DAVID ALLEN ABSTRACT The rates at which parts of the geological record have formed can be roughly determined using physical sedimentology independently from other dating methods if current understanding of the processes involved in sedimentology are accurate. Bedform and particle size observations are used here, along with sediment transport equations, to determine rates of transport and deposition in various geological sections. Calculations based on properties of some very extensive rock units suggest that those units have been deposited at rates faster than any observed today and orders of magnitude faster than suggested by radioisotopic dating. Settling velocity equations wrongly suggest that rapid fine particle deposition is impossible, since many experiments and observations (for example, Mt St Helens, mud- flows) demonstrate that the conditions which cause faster rates of deposition than those calculated here are not fully understood. For coarser particles the only parameters that, when varied through reasonable ranges, very significantly affect transport rates are flow velocity and grain diameter. Popular geological models that attempt to harmonize the Genesis Flood with stratigraphy require that, during the Flood, most deposition believed to have occurred during the Palaeozoic and Mesozoic eras would have actually been the result of about one year of geological activity. Flow regimes required for the Flood to have deposited various geological cross- sections have been proposed, but the most reliable estimate of water velocity required by the Flood was attained for a section through the Tasman Fold Belt of Eastern Australia and equalled very approximately 30 ms-1 (100 km h-1). -
25. PELAGIC Sedimentsi
^ 25. PELAGIC SEDIMENTSi G. Arrhenius 1. Concept of Pelagic Sedimentation The term pelagic sediment is often rather loosely defined. It is generally applied to marine sediments in which the fraction derived from the continents indicates deposition from a dilute mineral suspension distributed throughout deep-ocean water. It appears logical to base a precise definition of pelagic sediments on some limiting property of this suspension, such as concentration or rate of removal. Further, the property chosen should, if possible, be reflected in the ensuing deposit, so that the criterion in question can be applied to ancient sediments. Extensive measurements of the concentration of particulate matter in sea- water have been carried out by Jerlov (1953); however, these measurements reflect the sum of both the terrigenous mineral sol and particles of organic (biotic) origin. Aluminosilicates form a major part of the inorganic mineral suspension; aluminum is useful as an indicator of these, since this element forms 7 to 9% of the total inorganic component, 2 and can be quantitatively determined at concentration levels down to 3 x lO^i^ (Sackett and Arrhenius, 1962). Measurements of the amount of particulate aluminum in North Pacific deep water indicate an average concentration of 23 [xg/1. of mineral suspensoid, or 10 mg in a vertical sea-water column with a 1 cm^ cross-section at oceanic depth. The mass of mineral particles larger than 0.5 [x constitutes 60%, or less, of the total. From the concentration of the suspensoid and the rate of fallout of terrigenous minerals on the ocean floor, an average passage time (Barth, 1952) of less than 100 years is obtained for the fraction of particles larger than 0.5 [i. -
Sediment Transport in the San Francisco Bay Coastal System: an Overview
Marine Geology 345 (2013) 3–17 Contents lists available at ScienceDirect Marine Geology journal homepage: www.elsevier.com/locate/margeo Sediment transport in the San Francisco Bay Coastal System: An overview Patrick L. Barnard a,⁎, David H. Schoellhamer b,c, Bruce E. Jaffe a, Lester J. McKee d a U.S. Geological Survey, Pacific Coastal and Marine Science Center, Santa Cruz, CA, USA b U.S. Geological Survey, California Water Science Center, Sacramento, CA, USA c University of California, Davis, USA d San Francisco Estuary Institute, Richmond, CA, USA article info abstract Article history: The papers in this special issue feature state-of-the-art approaches to understanding the physical processes Received 29 March 2012 related to sediment transport and geomorphology of complex coastal–estuarine systems. Here we focus on Received in revised form 9 April 2013 the San Francisco Bay Coastal System, extending from the lower San Joaquin–Sacramento Delta, through the Accepted 13 April 2013 Bay, and along the adjacent outer Pacific Coast. San Francisco Bay is an urbanized estuary that is impacted by Available online 20 April 2013 numerous anthropogenic activities common to many large estuaries, including a mining legacy, channel dredging, aggregate mining, reservoirs, freshwater diversion, watershed modifications, urban run-off, ship traffic, exotic Keywords: sediment transport species introductions, land reclamation, and wetland restoration. The Golden Gate strait is the sole inlet 9 3 estuaries connecting the Bay to the Pacific Ocean, and serves as the conduit for a tidal flow of ~8 × 10 m /day, in addition circulation to the transport of mud, sand, biogenic material, nutrients, and pollutants. -
Sedimentation and Clarification Sedimentation Is the Next Step in Conventional Filtration Plants
Sedimentation and Clarification Sedimentation is the next step in conventional filtration plants. (Direct filtration plants omit this step.) The purpose of sedimentation is to enhance the filtration process by removing particulates. Sedimentation is the process by which suspended particles are removed from the water by means of gravity or separation. In the sedimentation process, the water passes through a relatively quiet and still basin. In these conditions, the floc particles settle to the bottom of the basin, while “clear” water passes out of the basin over an effluent baffle or weir. Figure 7-5 illustrates a typical rectangular sedimentation basin. The solids collect on the basin bottom and are removed by a mechanical “sludge collection” device. As shown in Figure 7-6, the sludge collection device scrapes the solids (sludge) to a collection point within the basin from which it is pumped to disposal or to a sludge treatment process. Sedimentation involves one or more basins, called “clarifiers.” Clarifiers are relatively large open tanks that are either circular or rectangular in shape. In properly designed clarifiers, the velocity of the water is reduced so that gravity is the predominant force acting on the water/solids suspension. The key factor in this process is speed. The rate at which a floc particle drops out of the water has to be faster than the rate at which the water flows from the tank’s inlet or slow mix end to its outlet or filtration end. The difference in specific gravity between the water and the particles causes the particles to settle to the bottom of the basin. -
Deep-Sea Mining: the Basics
A fact sheet from June 2018 NOAA Office of Ocean Exploration and Research Deep-sea Mining: The Basics Overview The deepest parts of the world’s ocean feature ecosystems found nowhere else on Earth. They provide habitat for multitudes of species, many yet to be named. These vast, lightless regions also possess deposits of valuable minerals in rich concentrations. Deep-sea extraction technologies may soon develop to the point where exploration of seabed minerals can give way to active exploitation. The International Seabed Authority (ISA) is charged with formulating and enforcing rules for all seabed mining that takes place in waters beyond national jurisdictions. These rules are now under development. Environmental regulations, liability and financial rules, and oversight and enforcement protocols all must be written and approved within three to five years. Figure 1 Types of Deep-sea Mining Production support vessel Return pipe Riser pipe Cobalt Seafloor massive Polymetallic crusts sulfides nodules Subsurface plumes 800-2,500 from return water meters deep Deposition 1,000-4,000 meters deep 4,000-6,500 meters deep Cobalt-rich Localized plumes Seabed pump Ferromanganeseferromanganese from cutting crusts Seafloor production tool Nodule deposit Massive sulfide deposit Sediment Source: New Zealand Environment Guide © 2018 The Pew Charitable Trusts 2 The legal foundations • The United Nations Convention on the Law of the Sea (UNCLOS). Also known as the Law of the Sea Treaty, UNCLOS is the constitutional document governing mineral exploitation on the roughly 60 percent of the world seabed that lies beyond national jurisdictions. UNCLOS took effect in 1994 upon passage of key enabling amendments designed to spur commercial mining. -
Calcareous Soils Are Alkaline
By Mongi Zekri, Tom Obreza and Kelly Morgan alcareous soils are alkaline (pH > 7) due to the pres- ence of excess calcium carbonate (CaCO3). These soils Ccan contain from 1 percent to more than 25 percent CaCO3 by weight, with pH in the range of 7.6 to 8.4. In Florida, soil pH is usually not higher than 8.4 regardless of CaCO3 concentration. Many Florida flatwoods soils contain one or more hori- zons (layers) that are calcareous. A typical characteristic is an alkaline, loamy horizon less than 40 inches deep that can be brought to the surface during land preparation for citrus Calcareous soil in Southwest Florida planting. Increased nutritional management intensity is re- quired to successfully grow citrus on calcareous soils. Some lution of fixed P. Applied P is available to replenish the soil grove soils (e.g. ditch banks) contain considerable amounts solution for only a relatively short time before it converts to of lime rock or shell. It may not be economically justifiable less soluble forms of P. To maintain P availability to citrus to plant these sites with certain rootstocks considering the on calcareous soils, water-soluble P fertilizer should be ap- management problems and costs involved. plied on a regular, but not necessarily frequent, basis. Since Citrus fertilizer management on calcareous soils differs P accumulates in the soil, it is at least partially available as from that on non-calcareous soils because the presence of it converts to less soluble compounds with time. CaCO3 directly or indirectly affects plant availability of N, Potassium (K) P, K, Calcium (Ca), Mg, Mn, Zn, Fe and Cu. -
Ngu Report 2017.046
Geological Survey of Norway P.O.Box 6315 Torgard REPORT NO-7491 TRONDHEIM Tel.: 47 73 90 40 00 ISSN: 0800-3416 (print) Report no.: 2017.046 ISSN: 2387-3515 (online) Grading: Open Title: Seabed sedimentary environments and sediments (genesis) in the Nordland VI area off northern Norway Authors: Valérie K. Bellec, Reidulv Bøe, Client: MAREANO Leif Rise, Aave Lepland, Terje Thorsnes County: Norway Commune: Map-sheet name (M=1:250.000) Map-sheet no. and -name (M=1:50.000) Deposit name and grid-reference: Number of pages: 24 Price (NOK): 110,- Map enclosures: 0 Fieldwork carried out: Date of report: Project no.: Person responsible: 2008-2016 15.12.2017 311720 Summary: This report presents maps of sedimentary environments and seabed sediments (genesis) in the Nordland VI management area off northern Norway. The maps, which cover about 25 000 km² and water depths from 60 m to 2700 m, are based on multibeam echosounder data (bathymetry and backscatter), 215 video lines each 700 m long, seabed sediment samples from 40 stations (grab, boxcore and multicore) and 5500 km of sub-bottom profiler data. The sedimentary environment map has 6 classes, focussing on present depositional environments (erosion and deposition). Large parts of the Nordland VI continental shelf are dominated by erosion processes, but some deposition occurs in topographic depressions and glacial troughs like Trænadjupet and Vesterdjupet. Hemipelagic sediments are deposited in deep water areas on the continental slope and abyssal plain. The seabed sediments (genesis) map comprises a geological interpretation of the uppermost few metres of the seabed, and has 10 classes. -
Progressive and Regressive Soil Evolution Phases in the Anthropocene
Progressive and regressive soil evolution phases in the Anthropocene Manon Bajard, Jérôme Poulenard, Pierre Sabatier, Anne-Lise Develle, Charline Giguet- Covex, Jeremy Jacob, Christian Crouzet, Fernand David, Cécile Pignol, Fabien Arnaud Highlights • Lake sediment archives are used to reconstruct past soil evolution. • Erosion is quantified and the sediment geochemistry is compared to current soils. • We observed phases of greater erosion rates than soil formation rates. • These negative soil balance phases are defined as regressive pedogenesis phases. • During the Middle Ages, the erosion of increasingly deep horizons rejuvenated pedogenesis. Abstract Soils have a substantial role in the environment because they provide several ecosystem services such as food supply or carbon storage. Agricultural practices can modify soil properties and soil evolution processes, hence threatening these services. These modifications are poorly studied, and the resilience/adaptation times of soils to disruptions are unknown. Here, we study the evolution of pedogenetic processes and soil evolution phases (progressive or regressive) in response to human-induced erosion from a 4000-year lake sediment sequence (Lake La Thuile, French Alps). Erosion in this small lake catchment in the montane area is quantified from the terrigenous sediments that were trapped in the lake and compared to the soil formation rate. To access this quantification, soil processes evolution are deciphered from soil and sediment geochemistry comparison. Over the last 4000 years, first impacts on soils are recorded at approximately 1600 yr cal. BP, with the erosion of surface horizons exceeding 10 t·km− 2·yr− 1. Increasingly deep horizons were eroded with erosion accentuation during the Higher Middle Ages (1400–850 yr cal. -
Sediment and Sedimentary Rocks
Sediment and sedimentary rocks • Sediment • From sediments to sedimentary rocks (transportation, deposition, preservation and lithification) • Types of sedimentary rocks (clastic, chemical and organic) • Sedimentary structures (bedding, cross-bedding, graded bedding, mud cracks, ripple marks) • Interpretation of sedimentary rocks Sediment • Sediment - loose, solid particles originating from: – Weathering and erosion of pre- existing rocks – Chemical precipitation from solution, including secretion by organisms in water Relationship to Earth’s Systems • Atmosphere – Most sediments produced by weathering in air – Sand and dust transported by wind • Hydrosphere – Water is a primary agent in sediment production, transportation, deposition, cementation, and formation of sedimentary rocks • Biosphere – Oil , the product of partial decay of organic materials , is found in sedimentary rocks Sediment • Classified by particle size – Boulder - >256 mm – Cobble - 64 to 256 mm – Pebble - 2 to 64 mm – Sand - 1/16 to 2 mm – Silt - 1/256 to 1/16 mm – Clay - <1/256 mm From Sediment to Sedimentary Rock • Transportation – Movement of sediment away from its source, typically by water, wind, or ice – Rounding of particles occurs due to abrasion during transport – Sorting occurs as sediment is separated according to grain size by transport agents, especially running water – Sediment size decreases with increased transport distance From Sediment to Sedimentary Rock • Deposition – Settling and coming to rest of transported material – Accumulation of chemical -
BUIL])ING STON.E O·F WASHINGTON
BUIL])ING STON.E o·f WASHINGTON By WAYNE S. MOEN Washington Department of Conservation Division of Mines and Geology Bulletin No. 55 1967 State of Washington DANIEL J. EV ANS, Governor Department of Conservation H. MAURICE AHLQUIST, Director DIVISION OF MINES AND GEOLOGY MARSHALL T. HUNTTING, Supervisor Bulletin No. 55 BUILDING STONE OF WASHINGTON By WAYNE S. MOEN STATE PRINTING PLANT. OLYMPI A , WASHINGTON 1967 For sale by Department Pof? ceConsl]SliARYervation, Olympia, Washington. PACIFIC NORTHWEST FOREST AND RANGE EXPERIMENT STATION etnDTLAND. OR£00N CONTENTS Poge Introduction 7 General history .. ...... ...........................•............ 8 Production and vo lue . 10 Forms of building stone . 12 Field stone . 12 Rough building stone . 13 Rubble . • . 14 Flogging (flagstone) . 14 Ashlar . .. ......... ........ , ................. , . , . 15 Crushed stone . 16 Terrozzo . 17 Roofing granules.............. .... ..... ......... 18 Exposed aggregate . 18 Reconstituted stone . • . 19 Landscape rock . 20 Area coverage of bui Iding stone . 21 Acquisition of bui )ding stone . 22 Examination of stone deposits . 23 General quarrying methods . 24 Physical properties of building stone . 26 Strength . 26 Hardness and workabi Iity . • . 27 Color . 28 Alteration ....•...................... , ........... , . 29 Porosity and absorption ...........•. : . 31 Testing of building stone... .. .................... ................ 33 Common building stones of Washington . 34 Granite . 35 Geology and distribution . 35 Physical properties . 38 Varieties -
Part 629 – Glossary of Landform and Geologic Terms
Title 430 – National Soil Survey Handbook Part 629 – Glossary of Landform and Geologic Terms Subpart A – General Information 629.0 Definition and Purpose This glossary provides the NCSS soil survey program, soil scientists, and natural resource specialists with landform, geologic, and related terms and their definitions to— (1) Improve soil landscape description with a standard, single source landform and geologic glossary. (2) Enhance geomorphic content and clarity of soil map unit descriptions by use of accurate, defined terms. (3) Establish consistent geomorphic term usage in soil science and the National Cooperative Soil Survey (NCSS). (4) Provide standard geomorphic definitions for databases and soil survey technical publications. (5) Train soil scientists and related professionals in soils as landscape and geomorphic entities. 629.1 Responsibilities This glossary serves as the official NCSS reference for landform, geologic, and related terms. The staff of the National Soil Survey Center, located in Lincoln, NE, is responsible for maintaining and updating this glossary. Soil Science Division staff and NCSS participants are encouraged to propose additions and changes to the glossary for use in pedon descriptions, soil map unit descriptions, and soil survey publications. The Glossary of Geology (GG, 2005) serves as a major source for many glossary terms. The American Geologic Institute (AGI) granted the USDA Natural Resources Conservation Service (formerly the Soil Conservation Service) permission (in letters dated September 11, 1985, and September 22, 1993) to use existing definitions. Sources of, and modifications to, original definitions are explained immediately below. 629.2 Definitions A. Reference Codes Sources from which definitions were taken, whole or in part, are identified by a code (e.g., GG) following each definition.