DOCSLIB.ORG

Sedimentology

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Sedimentology Sedimentology S.Cirilli-Sedimentology S. Cirilli: Sedimentology Sedimentology (9 cfu) Teacher Prof. Simonetta Cirilli ([email protected]) 0755852631 S.Cirilli-Sedimentology Course outline I. Fundamentals of Sedimentology II. Rock cycle and Sedimentary rocks: general introduction Classification of Sedimentary Rocks Siliciclastic sediments and rocks carbonate sediments and rocks: origin and classification This part will be briefly presented. Details on textures, mineralogical composition, rock classification and diagentic processes are matter of the Course on Sedimentary petrography S.Cirilli-Sedimentology I. Processi di trasporto e deposizione; principali strutture sedimentarie II. Analisi di facies e architetture deposizionali, geometrie e relazioni tra i corpi sedimentari. Relazioni tra subsidenza e sedimentazione. Ambienti sedimentari e modelli di facies IIa. Sistemi deposizionali e sedimenti terrigeno-clastici . depositi continentali: glaciali, eolici, fluviali, lacustri, . depositi costieri, deltizi e di mare basso III. Sedimentary processes, transport and deposition IV. Sedimentary structures S.Cirilli-Sedimentology V. Facies, Facies Models and Modern Stratigraphic Concepts VI. Facies and Sedimentary Environments: Facies analysis and depositional architectures - Siliciclastic dominated systems Alluvial Fans Desert Lacustrine Deposits River Deposits Delta Sedimentation Coastal Sedimentation The Shore Zone Barrier Islands Tidal Sedimentation Clastic ShallowMarine Shelves Carbonate shallow water platfrom Slope basin Deep-water depositional environments S. Cirilli: Sedimentology S.Cirilli-Sedimentology VII. Facies and Sedimentary Environments: Facies analysis and depositional architectures - Carbonate depositional settings Shallow water carbonate factories Peritidal depositional facies shelf margin distribution facies Platform slope distribution facies Basin depositional settings S.Cirilli-Sedimentology Textbooks James N.P & Dalrymple (2010) - Facies Models 4. GEOtext6. Geological Association of Canada Nichols G. (2009) - Sedimentology and Stratigraphy, 2nd Edition, 432 pages, Wiley-Blackwell Additional texts Reading H.G. (2004) third edition- Sedimentary Environments: Processes, Facies and Stratigraphy . Blackwell Science. pp.689. Richard C. Selley (2000)- Applied Sedimentology, Second Edition. Academic press D. Emery and K. Myers (a cura di) (2009) - Sequence Stratigraphy. pp.304. Wiley¸ Moore C.H. (2004) third edition – Carbonate reservoirs- porosity evolution and diagenesis in a sequence stratigraphic framework. Roger. M. Slatt (2007) - Stratigraphic Reservoir characterization for petroleum geologists, Geophysicists and Engineers. Handbook of Petroleum exploration and production, Vol.6, John Cubitt (Ed), Elsevier , pp. 478. S. Cirilli: Sedimentology Testi consigliati Reading H.G. (2004) third edition- Sedimentary Environments: Processes, Facies and Stratigraphy . Blackwell Science. pp.689. Richard C. Selley (2000)- Applied Sedimentology, Second Edition . Academic press Maurice E. Tucker: Geologia del sedimentario Editore: Flaccovio Dario Additional References and the Pdf of lectures will be provided by the teacher http://www.fisica.unipg.it/~sc570001/ S.Cirilli-Sedimentology Interpretation of systems SEQUENCE organization as a record of relative STRATIGRAPHY sea-level changes Analysis/reconstruction of depositional systems and recognition of their stratigraphic FACIES ANALYSIS organization THIS COURSE Recognition of ancient sedimentary environments (depositional systems) SEDIMENTOLOGY Recognition of sedimentation processes and structures S. Cirilli: Sedimentology S.Cirilli-Sedimentology Sedimentary Rocks Sedimentary rocks are those rocks which form at or near the earth's surface primarily through: Deposition of weathered silicate material by water, wind, or ice (detrital, clastic, terrigenous) Direct inorganic chemical precipitation from water Precipitation by organic processes S.Cirilli-Sedimentology Types of Sedimentary Rocks Clastic (terrigenous or detrital) Conglomerate or Breccia Sandstone Siltstone Shale Chemical/biochemical Carbonate sedimentary rocks (limestones and dolostone) Evaporites Siliceous sedimentary rocks Organic (coals) Other S.Cirilli-Sedimentology Sedimentary Rocks Clastic Rock – composed of fragments of preexisting rocks. Nonclastic Rock – composed of chemical precipitates or biogenic matter. S.Cirilli - Sedimentary Petrology Sedimentary environments: the framework Source glacial erosion glacial runoff weathering streams hillslope erosion fjords landslides Coral reefs deltaic & estuarine tidewater trapping fluvial transport primary floodplains productivity open shoreline slopes shelf shelf break abyssal plains Sink or basin floor Stratigraphy fans The composition of clastic rocks in sedimentary sequences depends to a large extent on the supply of sediments from source areas undergoing weathering and erosion. S.Cirilli-Sedimentology The physical properties of sedimentary rocks are controlled by the primary sediment composition and changes during burial (diagenesis). We shall here briefly look at the processes producing sediments. S.Cirilli-Sedimentology Weathering and Sedimentation in the Rock Cycle • The rock cycle is driven by surface processes: the hydrologic cycle (rainfall, streams, ice), gravity, aqueous chemistry. • Weathering, erosion and transportation are the processes that form and transport sediments. • Sedimentation, burial and lithification are the processes that transform weathering products into sedimentary rocks. S.Cirilli-Sedimentology Physical weath. produces fragments Weathering: decomposition of rocks Chemical weath. converts exposed rock to soil in place – The agent and duration of transportation and deposition strongly influence the character and distributions of the sediments S.Cirilli-Sedimentology Erosion and Transportation move dissolved or fragmented material from the source area where weathering is occurring to a depositional environment . Weathering The destruction of rocks at the Earth’s surface by weathering has two fundamental modes of operation: Physical and Chemical weathering Physical (or Mechanical) weathering is the physical breakdown of rocks (from outcrop) into smaller pieces which can then be transported as clastic sediment. Physical weathering makes loose pieces of rock available for downslope movement by mass wasting or transport in flowing water as suspended or bed load. S.Cirilli-Sedimentology Chemical weathering S.Cirilli-Sedimentology Chemical Weathering: Clay Minerals Generated strictly as a weather product by many types of chemical weathering + + KAlSi3O8 + 2H + 12H2O KAl3Si3O10(OH) 2 + 2K + 6H4SiO4 K-spar Muscovite Clay Hydrolysis + Hydration + + 2KAl3Si3O10(OH) 2 + 2H + 3H2O 3Al2Si2O5(OH) 4 + 2K Muscovite Clay Kaolinite Clay Hydrolysis + Hydration Al2Si2O5(OH) 4 + 5H2O 2Al(OH) 3 + 2H4SiO4 Kaolinite Clay Gibbsite Clay Hydrolysis + Hydration Smectite Yucca Mtn., Nev. Photo from Dr. Alan Jay Kaufman at http://www.geol.umd.edu/%7Ekaufman/kauf man.html Kaolinite 19 S.Cirilli-Sedimentology ΜϋϊϏϓϋϔϚχϘϟΐϋϕϒϕύϟ ΍ϋϖͨΎχϘϚώΜωϏͨͥΗχϚͨΌϋϔϚϘχϒΞϔϏϜͨ ΙϘϋϖχϘϋϊψϟ΍ϘͨΊϔϊϘϋϝΝͨΕϏϔ S.Cirilli-Sedimentology cement grains matrix S. Cirilli: Sedimentology These properties collectively make up the texture of a sediment or sedimentary rock. Each can be used to infer something of: The history of a sediment. The processes that acted during transport and deposition of a sediment. The behavior of a sediment. S. Cirilli: Sedimentology Sedimentary Textures refers as Grade Scales Grade scales define limits to a range of grain sizes for a given class (grade) of grain size Sets most boundaries to vary Sedimentologists use the by a factor of 2. Udden-Wentworth Grade Scale They provide a basis for a terminology that describes d(mm) grain size. φ = −log2 dO Where d = 1 mm. e.g., medium sand falls between O 0.25 and 0.5 mm. GRAIN SIZE A threefold division is used to name clastic sediments and sedimentary rocks (Udden- FORSE da METTERE? Wentworth Scale): 1) Gravel-sized grains are greater than 2mm in diameter 2) Sand-sized grains are between 2mm and 1/16mm (63 microns) across 3) Mud (clay and silt) is made of particles less than 63 mm in diameter. After Wentworth, 1922 S.Cirilli-Sedimentary Petrology TEXTURAL FEATURES Shape: defined in terms of closeness to a a sphere (similar length of a-, b- and c- axis) c b Disk Spheroid Blade Rod After Nichols, 2009 S. Cirilli: Sedimentology Sorting Sorting refers to the variation in size of particles making up sediment or sedimentary rocks. Sorting refers to uniformity of size. Very-well sorted sediment has only a small range of sizes (i.e: only grains 1.0-2.0 mm in diameter). Very poorly-sorted sediments shows a huge variation in clast size S. Cirilli: Sedimentology Sorting It results from processes that selectively transport and deposit sediments of particular sizes - well sorted sediments indicate gradually-changing velocities (like a stream) or extensive re-working (like a beach); or “selective” current as the wind - Poorly sorted sediments indicate not selective transport (e.g. gravity flow) S. Cirilli: Sedimentology Rounding is the degree to which detrital particles have their sharp corners and edges warn away by abrasion S. Cirilli S. Cirilli: Sedimentology TEXTURAL FEATURES ROUNDING Roundness: degree of surface smoothing After Pettijhon et al., 1987 Changes in Shape by Transport Transport of particles by water, wind or flowing glaciers has the potential to cause changes to their shape over time. Transport by wind or water results in rapid rounding Fragments might be angular if coming straight from an igneous or metamorphic source, or if moved by ice. S. Cirilli: Sedimentology.
Load more

Recommended publications
  • Geologic Storage Formation Classification: Understanding Its Importance and Impacts on CCS Opportunities in the United States
    BEST PRACTICES for: Geologic Storage Formation Classification: Understanding Its Importance and Impacts on CCS Opportunities in the United States First Edition Disclaimer This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference therein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed therein do not necessarily state or reflect those of the United States Government or any agency thereof. Cover Photos—Credits for images shown on the cover are noted with the corresponding figures within this document. Geologic Storage Formation Classification: Understanding Its Importance and Impacts on CCS Opportunities in the United States September 2010 National Energy Technology Laboratory www.netl.doe.gov DOE/NETL-2010/1420 Table of Contents Table of Contents 5 Table of Contents Executive Summary ____________________________________________________________________________ 10 1.0 Introduction and Background
    [Show full text]
  • Self-Guiding Geology Tour of Stanley Park
    Page 1 of 30 Self-guiding geology tour of Stanley Park Points of geological interest along the sea-wall between Ferguson Point & Prospect Point, Stanley Park, a distance of approximately 2km. (Terms in bold are defined in the glossary) David L. Cook P.Eng; FGAC. Introduction:- Geomorphologically Stanley Park is a type of hill called a cuesta (Figure 1), one of many in the Fraser Valley which would have formed islands when the sea level was higher e.g. 7000 years ago. The surfaces of the cuestas in the Fraser valley slope up to the north 10° to 15° but approximately 40 Mya (which is the convention for “million years ago” not to be confused with Ma which is the convention for “million years”) were part of a flat, eroded peneplain now raised on its north side because of uplift of the Coast Range due to plate tectonics (Eisbacher 1977) (Figure 2). Cuestas form because they have some feature which resists erosion such as a bastion of resistant rock (e.g. volcanic rock in the case of Stanley Park, Sentinel Hill, Little Mountain at Queen Elizabeth Park, Silverdale Hill and Grant Hill or a bed of conglomerate such as Burnaby Mountain). Figure 1: Stanley Park showing its cuesta form with Burnaby Mountain, also a cuesta, in the background. Page 2 of 30 Figure 2: About 40 million years ago the Coast Mountains began to rise from a flat plain (peneplain). The peneplain is now elevated, although somewhat eroded, to about 900 metres above sea level. The average annual rate of uplift over the 40 million years has therefore been approximately 0.02 mm.
    [Show full text]
  • Non-Clastic Sedimentary Rocks by Cindy Grigg
    Non-Clastic Sedimentary Rocks By Cindy Grigg 1 Rocks can be put into three main groups. They are grouped by how the rocks formed. Sedimentary (sed-uh-MEN-tuh-ree) rocks are formed on or near Earth's surface. Sedimentary rocks are sorted into other groups. They can be sorted as clastic or non-clastic. This group tells something about the rocks' beginning and what they formed from. 2 Non-clastic rocks are created when water evaporates or from the remains of plants and animals. Limestone is a non-clastic sedimentary rock. Limestone is made of the mineral calcite. It often contains fossils. Limestone formed in the ocean from the shells and skeletons of dead sea creatures. Some of the fossils in limestone are too small to be seen without a microscope. Chalk is a type of limestone that is usually white. It consists almost entirely of the shells of tiny dead sea creatures. Limestone is a common building material. 3 Coal is another non-clastic rock. It formed from the dead remains of plants. Millions of years ago, plants fell into swamps. They were covered with layers of sediment and did not rot. Over millions of years, as the remains were buried deeper under more and more layers of sediment, they were changed by pressure into coal. Coal is commonly used as fuel in power plants to make electricity. 4 Evaporite rocks formed when minerals such as gypsum and halite (rock salt) were left behind as water evaporated from oceans and lakes. Evaporite is common in desert areas, where evaporation is high, such as the Great Salt Lake in Utah.
    [Show full text]
  • 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.
    [Show full text]
  • Apollo 14 Lunar Sample Catalog
    1 Glossary of Terms Used in Petrographic Descriptions anorthite - triclinic plagioclase feldspar with the composition (Ca90-100, Na10-0) Al2Si208 anorthosite - rock name for an igneous rock (or lithic fragment) composed almost entirely of plagioclase (usually calcic plagioclase). Lunar anorthosites have a granulitic texture. basalt - a fine grained, usually dark colored, igneous rock which commonly is extrusive in origin. Composition of basalt, ordinarily, includes primarily calcic plagioclase, pyroxene, and other mafic minerals, such as olivine. breccia - a clastic rock with angular and broken rock fragments in a finer grained matrix. For purposes of this catalog, breccia fragments larger than 1 mm are designated as clasts, and those smaller than 1 mm are referred to as matrix. clast - fragmental part of a breccia larger than 1 mm. A clast may be lithic, mineral, or glass in lunar breccias. coherent- consolidated; not friable; doesn't crumble easily crystallite- a broad term applied to grains or crystals which are too small for identification dendritic - minerals that have crystallized in a branching or feathery pattern, commonly in a glassy matrix devitrified - said of a glass which has converted to a crystalline texture after its solidification fragmental rock - any clastic rock; rock composed of fragments of other rocks, minerals, or glass; includes breccias and microbreccias friable - said of a rock that crumbles naturally or is easily broken; poorly consolidated; poorly cemented; not coherent gabbro - coarse grained equivalent of
    [Show full text]
  • EPS 50 Lab 4: Sedimentary Rocks Grotzinger and Jordan, Chapter 5
    Name: _________________________ EPS 50 Lab 4: Sedimentary Rocks Grotzinger and Jordan, Chapter 5 Introduction In this lab we will classify sedimentary rocks and investigate the relationship between environmental conditions and sedimentary rock deposition. Remember that the diversity of rock in nature is generally continuous, and we are learning interpretive guidelines. The underlying principle for understanding sedimentary rocks and geological processes is that minerals and rocks are stable only under the conditions at which they form. If the temperature, pressure, water content, or other conditions change, the rocks will change to adapt to the new conditions. Objectives Learn to identify common sedimentary rocks (i.e. sandstone, shale, limestone and conglomerates) and the depositional environments they indicate. Learn to identify sedimentary structures and the processes that form them. Answers Please answer the numbered questions on the separate answer sheet handed out during lab. Only the answer sheet will be graded. Explanations should be concise—a few sentences or fewer. All answers should be your own, but we encourage you to discuss and check your answers with a few other students as you work through the exercises. ===================================================================== Sedimentary Rocks Sedimentary rocks form by the accumulation of sediment (eroded bits of pre-existing rocks) or by the precipitation of minerals out of solution. Sediment is deposited in a number of environments by moving air and water. Sedimentary rock identification is primarily based on composition. Texture can be used, but texture of a sedimentary rock has a slightly different meaning than texture of an igneous rock. In this lab, texture of a sedimentary rock refers to the origin or type of sediment found in the rock.
    [Show full text]
  • Sedimentary Rocks
    Name: ___________________________________________ Minerals and Rocks Date: __________________________ Period: ___________ The Physical Setting: Earth Science Lab Activity: Sedimentary Rocks INTRODUCTION: ! Sedimentary rocks are formed from an accumulation of sediments. Most of the time a sedimentary rock is formed from the materials that settle in quite waters. More often then not, the individual characteristics of the sediments can be found in the sedimentary rock it self. Geologist have classified sedimentary rocks into three categories called clastic, crystalline and bio- clastic. The clastic rocks are those formed mechanically where sediments are compacted or ce- mented together. Crystalline rocks form chemically from precipitates and evaporites and bioclastic rocks are composed of former living things. OBJECTIVE: ! Learn how to identify sedimentary rocks based on their properties. VOCABULARY: ! Clastic - Lithification -! Cementation -! Compaction - Crystalline - Bioclastic - PROCEDURE A: For each unknown sedimentary rocks, identify the key characteristics. After identifying the charac- teristics, use your Earth Science Reference Tables and determine the name of the rock based on your observations. Leigh-Manuell - "1 Lab Activity: Sedimentary Rocks Texture Texture Observations Rock Name ! Clastic ! Various sizes ! Sand sized: 0.006 - 0.2 cm ! Silt sized: 0.0004 - 0.006 cm ! Clay sized: less than 0.0004 cm ! Crystalline ! Fine to coarse ! Bioclastic ! Microscopic to very coarse Method of Lithification: ! Burial and Compaction ! Burial
    [Show full text]
  • Igneous Rocks Sedimentary Rocks Metamorphic Rocks
    Geology of the Pacific Northwest: Rocks and Minerals GEO143 Lab 5: ROCKS Name: _______________________________ Date: ________________ Igneous Rocks Igneous rocks form from the solidification of magma either below (intrusive igneous rocks) or above (extrusive igneous rocks) the Earth’s surface. For example, the igneous rock granite solidified below the Earth’s surface and is composed of several visible (to the naked eye) mineral grains such as quartz, orthoclase, biotite, and hornblende. The igneous rock basalt solidified above the Earth’s surface and is composed of non‐visible (to the naked eye) mineral grains. Sedimentary Rocks Pre‐existing rocks (igneous, sedimentary, and metamorphic) on the Earth’s surface that have been weathered, broken down into smaller particles, transported, deposited, and lithified (made solid) form sedimentary rocks. Sandstone, a sedimentary rock, is composed of inorganic sand‐sized (1/16 to 2 mm) particles that have been lithified together, forming clastic‐type sedimentary rocks. Limestone sedimentary rocks are typically formed by chemical precipitation of calcium carbonate or by lithified biogenic skeletal fragments of marine organisms comprised of calcium carbonate. Metamorphic Rocks Metamorphic rocks result from pre‐existing rocks that have been altered physically and/or chemically without melting. The agents of these changes include intense heat and pressure and/or chemical actions of hot fluids. The word metamorphic means meta (change) and morphic (form) – to change the pre‐ existing rock’s form. All metamorphic rocks form through a solid‐state transformation. For example, when the intrusive igneous rock granite is subjected to high pressures and temperatures, the original granite texture will transform to a new texture consisting of alternating light and dark mineral bands.
    [Show full text]
  • Earth Science Chapter 6
    Chapter6 Rocks Chapter Outline 1 ● Rocks and the Rock Cycle Three Major Types of Rock The Rock Cycle Properties of Rocks 2 ● Igneous Rock The Formation of Magma Textures of Igneous Rocks Composition of Igneous Rocks Intrusive Igneous Rock Extrusive Igneous Rock 3 ● Sedimentary Rock Formation of Sedimentary Rocks Chemical Sedimentary Rock Organic Sedimentary Rock Clastic Sedimentary Rock Characteristics of Clastic Sediments Sedimentary Rock Features 4 ● Metamorphic Rock Formation of Metamorphic Rocks Why It Matters Classification of The hundreds of different types of Metamorphic Rocks rocks on Earth can be classified into three main types: igneous, sedimentary, and metamorphic. This formation in Arizona is made of sedimentary rock. When you know the type of rock, you know something about how that rock formed. 132 Chapter 6 hq10sena_rxscho.indd 1 3/25/09 4:10:29 PM Inquiry Lab Sedimentary Sandwich 15 min Use slices of different types of bread to model Questions to Get You Started layers of different types of sediment deposits. Next, 1. Make a labeled diagram showing the rock layers in put your model in a plastic bag. Place a weight on the sample you observed. top of the bag to simulate the process of 2. Which factors might affect the thickness of a rock compacting sediment into rock. Then, use an empty layer in a real rock formation? film canister to obtain a core sample of the sedimentary sandwich. Trade samples with another 3. Your model has layers of different types of rocks. group and observe the other group’s sample. In a real formation, what might changes in Identify the different layers of rock and determine if rock type indicate about the rock layers are the same thickness or if some are formation’s geological history? thicker than others.
    [Show full text]
  • I Geology and Petrography of Volcanic Rocks of the Truk Islands, East Qqa .2 T»C Caroline Islands
    I Geology and Petrography of Volcanic Rocks of the Truk Islands, East QQa .2 t»C Caroline Islands 3 GEOLOGICAL SURVEY PROFESSIONAL PAPER 409 19 O QQ I 1 OQ Geology and Petrography of Volcanic Rocks of the Truk Islands, East Caroline Islands By J. T. STARK and R. L. HAY GEOLOGICAL SURVEY PROFESSIONAL PAPER 409 A structural, stratigraphic, and petrographic study of the rocks of a highly dissected, partly submerged inactive shield volcano UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1963 UNITED STATES DEPARTMENT OF THE INTERIOR STEWART L. UDALL, Secretary GEOLOGICAL SURVEY Thomas B. Nolan, Director For sale by the Superintendent of Documents, U.S. Government Printing Office Washington 25, D.C. CONTENTS Page Page Abstract- 1 16 Introduction . 1 Petrography of eastern and western islands 17 1 Olivine basalt 17 o Nepheline basalt 19 Melilite-nepheline basalt _ 20 Nepheline basanite - 20 Geology6J q Classification 20 4 9,0 Eastern islands . 5 Trachyte, ___ 21 Moen 5 22 Falo.. _-_.---.- 6 22 YanagL 6 22 Dublon Island 6 Andesite, basalt, and trachyte blocks 22 -CjTiGri 7 Gabbro blocks _ 23 Fefan. _ _ 7 25 Param _ 7 Tarik._ _ _____________ _____.-_ 8 Tsis _ - 8 OK Uman, Tako, and Atkin . __ q 25 9 Monzonite blocks- 26 q Limestone fragments 27 9 27 Chemical composition and variation diagrams _ 27 Lava flows and autoclastic breccias __ 9 29 Dikes 10 Conclusions 32 Udot__. ________________________________ 10 Eastern and western islands Eot 10 qq Eiol 11 qq 11 Trachyte and quartz trachyte. 34 11 Gabbro blocks 36 19 Recrystallized basalt blocks 38 12 Dikes of andesite and basalt in gabbro 38 12 Monzonite and quartz monzonite .
    [Show full text]
  • 6. Explanatory Notes1
    Collot, J.-Y., Greene, H. G., Stokking, L. B., et al., 1992 Proceedings of the Ocean Drilling Program, Initial Reports, Vol. 134 6. EXPLANATORY NOTES1 Shipboard Scientific Party2 In this chapter, we have assembled information that will and 12-kHz echo sounder, and magnetic data were recorded help the reader understand the basis for our preliminary across the planned drilling sites to aid site confirmation prior conclusions and also help the interested investigator select to dropping the beacon. samples for further analysis. This information concerns only The single-channel seismic profiling system used two 80- shipboard operations and analyses described in the site re- in.3 water guns as the energy source and a Teledyne streamer ports in the Initial Reports volume of the Leg 134 Proceedings with a 100-m-long active section. These data were recorded of the Ocean Drilling Program. Methods used by various digitally on tape using a Masscomp 561 super minicomputer, investigators for shore-based analysis of Leg 134 data will be and were also displayed in real time in analog format on two detailed in the individual scientific contributions published in Raytheon recorders using a variety of filter settings (common- the Scientific Results volume. ly 30-140 Hz) and two different scales (commonly 1- and 2-s sweeps and 50 traces/in.). AUTHORSHIP OF SITE CHAPTERS Bathy metric data collected using the 3.5- and 12-kHz The separate sections of the site chapters were written by precision depth recorder (PDR) system were displayed on two the following shipboard scientists (authors are listed in alpha- Raytheon recorders.
    [Show full text]
  • Sedimentary Rocks the Earth Science Journal Issue 10 November 2013
    SEDIMENTARY ROCKS THE EARTH SCIENCE JOURNAL ISSUE 10 NOVEMBER 2013 IN THIS ISSUE Sedimentary Rocks P.1 Bioclastic Rocks P.1 Sediment and Clastic Rocks P.2 Sedimentary Rocks Crystalline Rocks P.2 Sedimentary rocks are unique and varied in nature. They form in one of three ways: (1) from the compaction and cementation of sediments as a clastic rock, (2) from chemical precipitates in solution or evaporates as a crystalline rock, and (3) from compacted plant or animal remains Bioclastic Rocks as a bioclastic rock. Bioclastic rocks are wholly or partial- Clastic rocks are probably the most abundant type of sedimentary rock. Examples include: ly comprised of compacted plant or conglomerate, breccia, sandstone, siltstone, and shale. Each of these 5 rocks are uniquely animal remains. Bioclastic rocks will identified by the sediments that they contain and their characteristics (for more on the 6 types often have fossils within them upon discovery. A classic example of this of sediments, turn to page 2). Clastic rocks form when water surrounding sediments evapo- can be found in samples of coqui- rates and the dissolved minerals in the water act as a cement locking the sediments together. na— a bioclastic rock made up most- ly of shell fragments. This indicates When chemical reactions or evaporation occurs, crystalline rocks may form. Many of the ma- that the environment the rock jor rock salt deposits found in New York State are the result of evaporation of ancient sea- formed in was likely a very shallow water. Limestone and Rock Gypsum are two additional examples of common crystalline rocks.
    [Show full text]