DOCSLIB.ORG

Carbonates, Et Al

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Carbonates, Et Al GEOL 332 Lab 5 Sedimentary Rock Identification II Name: _____________________________________________ Date: _______________ Sedimentary Rocks: Carbonates, et al. Lab Equipment List: hand lens, ruler, pencil, and eraser. Objectives 1) to become familiar with the properties important in recognizing and classifying sedimentary rocks 2) to become familiar with the textures characteristic of sedimentary rocks; Carbonate Sedimentary Rock Classification In a simple model for the evolution of sedimentary rocks we find that if weathering, transportation, and sorting go to completion all that remains are three end member rock compositions. Siliciclastic Rocks: Quartz Arenite / Shale Carbonate Rocks: Limestone / Dolomite Limestones are not single composition rocks but a group of related rocks all composed of CaCO3 and reacting with dilute HCl acid. Limestone [CaCO3] is also chemically related to Dolomite [CaMg (CO3)2]. Because all these rocks have CO3 in common they are called the Carbonates. The composition of most Carbonates is derived from a combination of biological and chemical components. Two Carbonate classification systems are used today, one by R.L. Folk and the second by R.J. Dunham. The Dunham system is based on depositional texture (that is, the amount of matrix surrounding the grains at the time of deposition). It uses such names as Mudstone, wackestone, packstone, grainstone, and boundstone. Carbonate rock names (Limestones and Dolomites) consist of a conjunction of two names, one describing the ALLOCHEMS, the large pieces, the other describing the INTERSTITIAL MATERIAL. Allochems are equivalent to gravel, sand, lithics or feldspars in the siliciclastics. Interstitial material is equivalent to Clay or cements in clastics. There are four kinds of allochems: 1. Fossils ‐ may be whole fossils, or broken and abraded fossils; all are called "bio" fragments 2. Oolites ‐ small spheres 3. Pellets ‐ fecal Pellets produced by invertebrate animals; look superficially like Oolites but are dull 4. Intraclasts ‐ chunks of eroded Limestone deposited as a Conglomerate 1 | Page GEOL 332 Lab 5 Sedimentary Rock Identification II Interstitial Material Micrite is "lime mud", the dense, dull‐looking sediment made of Clay sized crystals of CaCO3. Micrite forms from the breakdown of calcareous algae skeletons. It is not clear if all ancient Micrites formed in the same way. Many Carbonates are composed of nearly 100% Micrite. Such rocks are simply called Micrites. With Carbonates containing allochems the question is whether Micrite is present or absent as an interstitial material, and if present, by how much. If Micrite is present during deposition then it fills the spaces between the allochems and the rock will be given a name which describes the allochems in a Micrite matrix. For example, a rock with fossil fragments embedded in Micrite is called a "Biomicrite". If the depositional environment has strong currents, only allochems may be deposited. If we could see the sediment during deposition and all the allochems would be loose, like a pure sand or gravel. This is analogous to a 100% siliciclastic sand on a beach with no silt or Clay. In this case, Micrite would be clay‐ sized and would be washed away. The rock formed is then composed only of allochems, held together by clear to translucent Calcite crystals with rhombohedral cleavage (called SPAR or SPARITE) acting as a cement. The spar is precipitated from fresh or marine water percolating through the sediment after deposition, but before final cementation. Classification of Carbonates The classification of Carbonates using the allochem/interstitial material system (the Folk System) is very systematic and straight forward. The allochem name is combined with the interstitial name (Micrite or spar). The table below shows the major categories of Carbonate rocks based on their allochems and interstitial material. But what happens if there is more than one allochem in the rock, or there is a mixture of Micrite and spar? You can easily build your own descriptive rock names. The name is built up by stringing together 2 | Page GEOL 332 Lab 5 Sedimentary Rock Identification II all the allochem names in order from least to most abundant, and then adding the interstitial material name ("matrix" below for short). For example, a rock like this: Oolites + Fossils + Spar matrix = Oo bio sparite o The name is written as one word, Oobiosparite. Another example (again allochems from least to most abundant): Pellets + Oolites + Fossils + Micrite matrix = pel oo bio Micrite o The name is written as one word, Peloobiomicrite. But what if there is both Micrite and spar matrix? The system is the same; just list them from least to most abundant. Fossils + Spar matrix + Micrite matrix = bio spar Micrite This system goes through other levels of refinement, such as in the table below where the abundance of allochems is indicated. Other modifiers may deal with different sizes of allochems. A classification such as this one works well if you want to construct rock names from observations. The system, however, does not lend itself well to constructing keys for classification. A key requires the establishment of arbitrary categories of rocks, and a system like the one above deals with all the myriad combinations that are possible. Most limestones are classified by Folk allochemical rocks if they contain over l0% allochems (transported carbonate grains). Based on the percentage of interstitial material, the rocks may be further subdivided into two groups: sparry allochemical limestones (containing a sparry calcite cement of clear coarsely crystalline mosaic calcite crystals) and microcrystalline allochemical limestone (containing microcrystalline calcite mud, micrite, which is subtranslucent grayish or brownish particles less than about 5 microns in size). Further subdivision is based on the allochem ratios of Folk (1962) are shown in Scholle & Ulmer‐Scholle (2003). Thus Folk's classification is most suited for thin section study. Remember that he terms rocks with appreciable matrix as micrites while matrix‐free rocks that contain sparry calcite cement are termed sparites. As you can see sparites and micrites are further subdivided by means of their most common grains. 3 | Page GEOL 332 Lab 5 Sedimentary Rock Identification II In contrast, Dunham's classification (figures above) and its modification by Embry and Klovan (1971) and James (1984) deals with depositional texture. For this reason, his scheme may be better suited for rock descriptions that employ a hand lens or binocular microscope. For example, if the grains of a limestone are touching one another and the sediment contains no mud, then the sediment is called a grainstone. If the carbonate is grain supported but contains a small percentage of mud, then it is known as a packstone. If the sediment is mud supported but contains more than 10 percent grains, then it is known as a wackestone, and if it contains less than 10 percent grains and is mud supported, it is known as a mudstone. If one compares the two classifications, a rock rich in carbonate mud is termed a micrite by Folk and a mudstone or wackestone by Dunham. Moreover, a rock containing little matrix is termed a sparite by Folk and a grainstone or packstone by Dunham. The wide range of percentage of mud matrix that a carbonate may have and still be termed a packstone by Dunham sometimes reduces the utility of this classification. Embry has modified Dunham's classification and Klovan (1971) to include coarse grained carbonates (above figure). In their revised scheme, a wackestone in which the grains are greater than 2mm in size is termed a floatstone and a coarse grainstone is called a rudstone. Both terms are extremely useful in description of limestones. Embry and Klovan to more graphically reflect the role that the organisms performed during deposition also modified the boundstone classification of Dunham. Terms such as bafflestone, bindstone, and framestone are useful in concept but are extremely difficult to apply to ancient limestones where diagenesis and sample size limit one’s ability to assess an organism’s function. The last two pages of this lab includes a key to identify rocks based on their allochems and interstitial material. Just be aware that its main weakness is that there are always rocks that do not fit easily into its simple categories. There is also a chemical and biochemical rock identification key. 4 | Page GEOL 332 Lab 5 Sedimentary Rock Identification II Folk Sedimentary Rock Classification: Folk’s (1959, 1962) classification of limestones, which uses prefixes to indicate the framework grains present (bio‐ for fossils, pel‐ for peloids, oo‐ for Ooids, and intra‐ for intraclasts) and stems to indicate whether the interstitial calcite is micritic or sparry. If the rock is originally bound together (as in a reef rock), it is a biolithite. 5 | Page GEOL 332 Lab 5 Sedimentary Rock Identification II Textural maturity classification of limestones proposed by Folk (1962). Textural maturity classes are based on the percentage of allochems present, their degree of sorting, and the extent of rounding (a function of abrasion history). (Folk, 1965) The Dunham classification of carbonate sedimentary rocks (Dunham 1962) with modifications by Embry & Klovan (1971). This scheme is the most commonly used for description of limestones in the field and in hand specimen. Rock Identification Step 1, fill out the table for the known sedimentary rock samples. (15 pts) Step 3, fill out the table for the unknown sedimentary rock samples. (15 pts) 6 | Page GEOL 332 Lab 5 Sedimentary Rock Identification II (Dunham, 1962) 7 | Page GEOL 332 Lab 5 Sedimentary Rock Identification II 8 | Page GEOL 332 Lab 5 Sedimentary Rock Identification II References: Dunham, R. J., 1962, Classification of carbonate rocks according to depositional texture. In: Ham, W. E. (ed.), Classification of carbonate rocks: American Association of Petroleum Geologists Memoir, p. 108‐ 121. Embry, AF, and Klovan, JE, 1971, A Late Devonian reef tract on Northeastern Banks Island, NWT: Canadian Petroleum Geology Bulletin, v.
Load more

Recommended publications
  • Determination of Carbonate Rock Chemistry Using Laboratory-Based Hyperspectral Imagery
    Remote Sens. 2014, 6, 4149-4172; doi:10.3390/rs6054149 OPEN ACCESS remote sensing ISSN 2072-4292 www.mdpi.com/journal/remotesensing Article Determination of Carbonate Rock Chemistry Using Laboratory-Based Hyperspectral Imagery Nasrullah Zaini 1,2,*, Freek van der Meer 1 and Harald van der Werff 1 1 Department of Earth Systems Analysis, Faculty of Geo-Information Science and Earth Observation (ITC), University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands; E-Mails: [email protected] (F.M.); [email protected] (H.W.) 2 Department of Physics, Faculty of Mathematics and Natural Sciences, Syiah Kuala University, Darussalam, Banda Aceh, 23111 Aceh, Indonesia * Author to whom correspondence should be addressed; E-Mail: [email protected]; Tel.: +31-534-874-444; Fax: +31-534-874-400. Received: 6 December 2013; in revised form: 11 April 2014 / Accepted: 28 April 2014 / Published: 5 May 2014 Abstract: The development of advanced laboratory-based imaging hyperspectral sensors, such as SisuCHEMA, has created an opportunity to extract compositional information of mineral mixtures from spectral images. Determining proportions of minerals on rock surfaces based on spectral signature is a challenging approach due to naturally-occurring minerals that exist in the form of intimate mixtures, and grain size variations. This study demonstrates the application of SisuCHEMA hyperspectral data to determine mineral components in hand specimens of carbonate rocks. Here, we applied wavelength position, spectral angle mapper (SAM) and linear spectral unmixing (LSU) approaches to estimate the chemical composition and the relative abundance of carbonate minerals on the rock surfaces. The accuracy of these classification methods and correlation between mineral chemistry and mineral spectral characteristics in determining mineral constituents of rocks are also analyzed.
    [Show full text]
  • Dissolution of Carbonate Rocks in a Laboratory Setting: Rates and Textures
    minerals Article Dissolution of Carbonate Rocks in a Laboratory Setting: Rates and Textures Erik B. Larson 1,* and Ronald V. Emmons 1,2 1 Department of Natural Sciences, Shawnee State University, 940 Second St, Portsmouth, OH 45662, USA; [email protected] 2 Department of Chemistry and Biochemistry, The University of Toledo, 2801 W. Bancroft St, Toledo, OH 43606, USA * Correspondence: [email protected]; Tel.: +1-740-351-3144 Abstract: Determining the dissolution rates of carbonate rocks is vital to advancing our under- standing of cave, karst, and landscape processes. Furthermore, the role of carbonate dissolution is important for the global carbon budget and climate change. A laboratory experiment was setup to calculate the dissolution rates of two whole rock carbonate samples with different petrographic makeup (ooids and brachiopods). The carbonate rock samples were also explored under a scanning electron microscope to evaluate the textures that developed after dissolution The oolitic limestone dissolved at a rate of 1579 cm yr−1, and the pentamerous limestone (dolostone) dissolved at a rate of 799 cm yr−1. Both rocks did not dissolve evenly across their surface as indicated by scanning electron microscopy, it appears the allochems dissolved preferentially to the matrix/cement of the rocks and that some mechanical weathering happened as well. This work reports that the petrography and mineralogy of carbonate rocks is important to consider when exploring the cave, karst, and landscape evolution and that attention should be paid to the petrography of carbonate rocks when considering Citation: Larson, E.B.; Emmons, R.V. the global carbon budget.
    [Show full text]
  • Bedrock Geology Glossary from the Roadside Geology of Minnesota, Richard W
    Minnesota Bedrock Geology Glossary From the Roadside Geology of Minnesota, Richard W. Ojakangas Sedimentary Rock Types in Minnesota Rocks that formed from the consolidation of loose sediment Conglomerate: A coarse-grained sedimentary rock composed of pebbles, cobbles, or boul- ders set in a fine-grained matrix of silt and sand. Dolostone: A sedimentary rock composed of the mineral dolomite, a calcium magnesium car- bonate. Graywacke: A sedimentary rock made primarily of mud and sand, often deposited by turbidi- ty currents. Iron-formation: A thinly bedded sedimentary rock containing more than 15 percent iron. Limestone: A sedimentary rock composed of calcium carbonate. Mudstone: A sedimentary rock composed of mud. Sandstone: A sedimentary rock made primarily of sand. Shale: A deposit of clay, silt, or mud solidified into more or less a solid rock. Siltstone: A sedimentary rock made primarily of sand. Igneous and Volcanic Rock Types in Minnesota Rocks that solidified from cooling of molten magma Basalt: A black or dark grey volcanic rock that consists mainly of microscopic crystals of pla- gioclase feldspar, pyroxene, and perhaps olivine. Diorite: A plutonic igneous rock intermediate in composition between granite and gabbro. Gabbro: A dark igneous rock consisting mainly of plagioclase and pyroxene in crystals large enough to see with a simple magnifier. Gabbro has the same composition as basalt but contains much larger mineral grains because it cooled at depth over a longer period of time. Granite: An igneous rock composed mostly of orthoclase feldspar and quartz in grains large enough to see without using a magnifier. Most granites also contain mica and amphibole Rhyolite: A felsic (light-colored) volcanic rock, the extrusive equivalent of granite.
    [Show full text]
  • Economic Geology Report ER79-4: Porphyritic Intrusions and Related
    MANITOBA CANADA DEPARTMENT OF ENERGY AND MINES MANITOBA MINERAL RESOURCES DIVISION ECONOMIC GEOLOGY REPORT ER79-4 PORPHYRITIC INTRUSIONS AND RELATED MINERALIZATION IN THE FLIN FLON VOLCANIC BELT by D.A. BALDWIN 1980 Funding for this project was provided under the cost-shared Canada-Manitoba Non-renewable Resources Evaluation Program by the Canada Department of Energy, Mines and Resources and the Manitoba Department of Mines, Resources and Environmental Management. MANITOBA DEPARTMENT OF ENERGY AND MINES HON. DONALD W. CRAIK PAUL E. JARVIS Minister Deputy Minister MINERAL RESOURCES DIVISION IAN HAUGH Executive Director ECONOMIC GEOLOGY REPORT ER79-4 PORPHYRITIC INTRUSIONS AND RELATED MINERALIZATION IN THE FLIN FLON VOLCANIC BELT by D.A. BALDWIN 1980 LEGEND I Cliff Lake Stock 5 Elbow Lake Stock 2 Whitefish Lake Porphyry 6 Fourmile Island Intrusion 3 Alberts Lake Intrusion 7 Chisel Lake Intrusion 4 Nisto Lake Intrusion 8 Wekusko Lake Intrusion ,~ -./ - -, I \." ~herridon '" , ;. <,.... ,1 if 55°00' 55°00' c, t,:) ,J -3 , I"" . c;? '" 1[' . ::t} \'''If!? ~,/J~ /j' ., ~), F lin.~ i;\))F ' I,".!0l~' ,d ' ;)/", ' ~.;'. l ;' ~" ,r~n ;t j; (I:/,1 ,r Lake ' \\ ;\~ ' ~i'/ 'lUi':;- -'i' //{ ,'/ , ,\" ,,/,1,1 pI , .h .(,1;' '\:. (IiI' ' .. '~'4_hl i / 'Y{j,'{:" 5 2.5 a 10 15 KILOMETRES J!) "'.t3 f3,F-"\ ---- :i~ f)J~c~. V 99°30' ">/)AfhapaplJskoj¥ !ZJ Porphyritic Intrusive Rocks 54°30' ! ,1 Lake .; ... 100°30' D Felsic Volcanic Rocks FIGURE 1: Distribution of porphyritic intrusive and felsic volcanic rocks in the Flin Flon volcanic belt, TABLE OF
    [Show full text]
  • Contribution of Carbonate Rock Weathering to the Atmospheric CO2
    Cases and solutions Contribution of carbonate rock weathering to the atmospheric CO2 sink Z. Liu ´ J. Zhao Introduction Abstract To accurately predict future CO2 levels in the atmosphere, which is crucial in predicting It is known Quay 1992; Watson and others 1990) that global climate change, the sources and sinks of the the combustion of fossil fuels releases about 5.4 billion atmospheric CO and their change over time must 2 tons of carbon a year as CO2 into the atmosphere. In be determined. In this paper, some typical cases addition, deforestation practices contribute about 1.6 bil- are examined using published and unpublished lion tons of carbon a year to atmospheric CO . Therefore, data. Firstly, the sensitivity of carbonate rock 2 the total input of CO2 from human activities is about weathering including the effects by both dissolu- 7.0 billion tons of carbon annually. However, only about tion and reprecipitation of carbonate) to the change 3.4 billion tons of carbon a year accumulates in the of soil CO and runoff will be discussed, and then 2 atmosphere. That means there is an atmospheric CO2 the net amount of CO2 removed from the atmos- sink of about 3.6 billion tons of carbon a year. phere in the carbonate rock areas of mainland To accurately predict future CO2-levels in the atmos- China and the world will be determined by the phere, which is crucial in predicting climate change, the hydrochem-discharge and carbonate-rock-tablet CO2 sinks and their change with time must be deter- methods, to obtain an estimate of the contribution mined.
    [Show full text]
  • Constraints on Sedimentary Ages of the Chuanlinggou Formation in the Ming Tombs, Beijing, North China Craton: LA-ICP-MS and SHRIMP U–Pb Dating of Detrital Zircons
    Acta Geochim (2018) 37(2):257–280 https://doi.org/10.1007/s11631-017-0211-1 ORIGINAL ARTICLE Constraints on sedimentary ages of the Chuanlinggou Formation in the Ming Tombs, Beijing, North China Craton: LA-ICP-MS and SHRIMP U–Pb dating of detrital zircons 1,2 1 1,3 4 Jing Ding • Yuruo Shi • Alfred Kro¨ner • J. Lawford Anderson Received: 13 November 2016 / Revised: 10 February 2017 / Accepted: 16 August 2017 / Published online: 1 September 2017 Ó Science Press, Institute of Geochemistry, CAS and Springer-Verlag GmbH Germany 2017 Abstract Detrital zircons in five sedimentary samples, the Chuanlinggou Formation in the Ming Tombs District MC1 to MC5, from the bottom of the Chuanlinggou For- was deposited in a low-energy mud flat sedimentary mation in the Ming Tombs District, Beijing, were dated environment in the inter-supra tidal zone because it is with the LA-ICP-MS and SHRIMP U–Pb methods. Age mainly composed of silty mudstone and fine-grained spectra of the five samples show a major peak at 2500 Ma sandstone with relatively simple sedimentary structures. and a secondary peak at 2000 Ma, suggesting their provenances were mainly from the crystalline basement of Keywords Detrital zircon Á LA-ICP-MS U–Pb ages Á the North China Craton and the Trans-North China Orogen. SHRIMP Á Chuanlinggou Formation Á Ancient sedimentary The youngest zircon has an age of 1673 ± 44 Ma, indi- environment Á North China Craton cating that the Chuanlinggou Formation was deposited after this age. From sample MC4 to MC5, lithology changed from a clastic rock (fine-grained sandstone) to a 1 Introduction carbonate rock (fine-grained dolomite), suggesting that the depositional basin became progressively deeper.
    [Show full text]
  • Carbonate Geology and Hydrology of the Edwards Aquifer in the San
    Report 296 Carbonate Gec>logy and Hydrology ()f the Edwards Aquifer in the San Antonio Ar~ea, Texas November 1986 TEXAS WATER DEVELOPMENT BOARD REPORT 296 CARBONATE GEOLOGY AND HYDROLOGY OF THE EDWARDS AQUIFER IN THE SAN ANTONIO AREA, TEXAS By R. W. Maclay and T. A. Small U.S. Geological Survey This report was prepared by the U.S. Geological Survey under cooperative agreement with the San Antonio City Water Board and the Texas Water Development Board November 1986 TEXAS WATER DEVELOPMENT BOARD Charles E. Nemir. Executive Administrator Thomas M. Dunning, Chairman Stuart S. Coleman. Vice Chairman Glen E. Roney George W. McCleskey Charles W. Jenness Louie Welch A uthorization for use or reproduction ofany originalmaterial containedin this publication. i.e., not obtained from other sources. is freely granted. The Board would appreciate acknowledgement. Published and distributed by the Texas Water Development Board Post Office Box 13231 Austin. Texas 78711 ii ABSTRACT Regional differences in the porosity and permeability of the Edwards aquifer are related to three major depositional areas, the Maverick basin, the Devils River trend, and the San Marcos platform, that existed during Early Cretaceous time. The rocks of the Maverick basin are predominantly deep basinal deposits of dense, homogeneous mudstones of low primary porosity. Permeability is principally associated with cavernous voids in the upper part of the Salmon Peak Formation in the Maverick basin. The rocks of the Devils River trend are a complex of marine and supratidal deposits in the lower part and reefal or inter-reefal deposits in the upper part. Permeable zones, which occur in the upper part ofthe trend, are associated with collapse breccias and rudist reefs.
    [Show full text]
  • Statistics and Segmentation: Using Big Data to Assess Cascades Arc
    This article is a non-peer reviewed preprint published at EarthArXiv. The article is in review by Geochimica et Cosmochimica Acta. 1 Statistics and segmentation: 2 Using Big Data to assess Cascades Arc compositional variability 3 Bradley W. Pitcher1 and Adam JR. Kent2 4 5 1Earth and Environmental Sciences department, Vanderbilt University, Nashville, TN 32701. 6 Email: [email protected] 7 2College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR 97333. 8 Email: [email protected] 9 10 11 Abstract 12 Primitive lavas erupted in the Cascades arc of western North America demonstrate significant 13 patterns of along-arc heterogeneity. Such compositional diversity may be the result of 14 differences in mantle melting processes, subduction geometry, regional tectonics, or 15 compositions of the slab, mantle or overlying lithosphere. Previous authors have partitioned the 16 arc into four geochemically distinct segments in order to assess the importance and relative roles 17 of these potential causes (Schmidt et al., 2008). However, despite the immense amount of data 18 available from the Cascade arc, no previous study has utilized a statistical approach on a 19 comprehensive dataset to address such a fundamental petrologic question. To better characterize 20 the heterogeneity of the entire arc, we compiled >250,000 isotopic, major, and trace element 21 analyses (glass and whole rock) from nearly 13,000 samples. To minimize inherent sampling 22 bias – the effect where well-studied volcanoes heavily weight conclusions – we use a weighted 23 bootstrap Monte Carlo approach in which the probability of a sample being selected to the 24 posterior distribution was inversely proportional to the number of samples within its 0.25° 25 latitude bin.
    [Show full text]
  • Processing and Characterization of Basalt Fiber Reinforced Ceramic Composites for High Temperature Applications Using Polymer Precursors
    PROCESSING AND CHARACTERIZATION OF BASALT FIBER REINFORCED CERAMIC COMPOSITES FOR HIGH TEMPERATURE APPLICATIONS USING POLYMER PRECURSORS Sarah B. Cox, Donovan Lui, Xin Wang, Jihua Gou Department of Mechanical and Aerospace Engineering University of Central Florida Orlando, FL, 32816 ABSTRACT The development of high temperature structural composite materials has been very limited due to the high cost of the materials and the processing needed. Ceramics can take much higher temperatures, but they are difficult to produce and form in bulk volumes. Polymer Derived Ceramics (PDCs) begin as a polymer matrix, allowing a shape to be formed and cured and then to be pyrolized in order to obtain a ceramic with the associated thermal and mechanical properties. The two PDCs used in this development are polysiloxane and polycarbosilane. Polysiloxanes contain a silicon oxycarbide backbone when pyrolized up to 1000°C. Polycarbosilane, an organosilicon polymer, contain a silicon-carbon backbone; around 1200°C, β-SiC begins to crystallize. The use of basalt in structural and high temperature applications has been under development for over 50 years, yet there has been little published research on the incorporation of basalt fibers as a reinforcement in composites. Basalt is a naturally occurring material found in volcanic rock. Continuous basalt fiber reinforced PDCs have been fabricated and tested for the applicability of this composite system as a high temperature structural composite material. Thermal and mechanical testing includes oxyacetylene torch testing and three point bend testing. 1. INTRODUCTION In the aerospace industry, as the need for high performance vehicles grows, the need for materials which can meet these high performance levels becomes even more important.
    [Show full text]
  • The Clumped-Isotope Geochemistry of Exhumed Marbles from Naxos, Greece U
    The clumped-isotope geochemistry of exhumed marbles from Naxos, Greece U. Ryb, M.K. Lloyd, D.A. Stolper, J.M. Eiler Abstract Exhumation and accompanying retrograde metamorphism alter the compositions and textures of metamorphic rocks through deformation, mineral–mineral reactions, water–rock reactions, and diffusion-controlled intra- and inter-mineral atomic mobility. Here, we demonstrate that these processes are recorded in the clumped- and single-isotope (δ13Cand δ18O) compositions of marbles, which can be used to constrain retrograde metamorphic histories. We collected 27 calcite and dolomite marbles along a transect from the rim to the center of the metamorphic core-complex of Naxos (Greece), and analyzed their carbonate single- and clumped-isotope compositions. The majority of Δ47 values of whole-rock samples are consistent with exhumation- controlled cooling of the metamorphic complex. However, the data also reveal that water–rock interaction, deformation driven recrystallization and thermal shock associated with hydrothermal alteration may considerably impact the overall distribution of Δ47 values. We analyzed specific carbonate fabrics influenced by deformation and fluid– rock reaction to study how these processes register in the carbonate clumped-isotope system. Δ47 values of domains drilled from a calcite marble show a bimodal distribution. Low Δ47 values correspond to an apparent temperature of 260 °C and are common in static fabrics; high Δ47values correspond to an apparent temperature of 200 °C and are common in dynamically recrystallized fabrics. We suggest that the low Δ47 values reflect diffusion-controlled isotopic reordering during cooling, whereas high Δ47 values reflect isotopic reordering driven by dynamic recrystallization. We further studied the mechanism by which dynamic recrystallization may alter Δ47 values by controlled heating experiments.
    [Show full text]
  • Data of Geochemistry
    Data of Geochemistry ' * Chapter W. Chemistry of the Iron-rich Sedimentary Rocks GEOLOGICAL SURVEY PROFESSIONAL PAPER 440-W Data of Geochemistry MICHAEL FLEISCHER, Technical Editor Chapter W. Chemistry of the Iron-rich Sedimentary Rocks By HAROLD L. JAMES GEOLOGICAL SURVEY PROFESSIONAL PAPER 440-W Chemical composition and occurrence of iron-bearing minerals of sedimentary rocks, and composition, distribution, and geochemistry of ironstones and iron-formations UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1966 UNITED STATES DEPARTMENT OF THE INTERIOR STEWART L. UDALL, Secretary GEOLOGICAL SURVEY William T. Pecora, Director For sale by the Superintendent of Documents, U.S. Government Printing Office Washington, D.C. 20402 - Price 45 cents (paper cover) CONTENTS Page Face Abstract. _ _______________________________ Wl Chemistry of iron-rich rocks, etc. Continued Introduction. _________ ___________________ 1 Oxide facies Continued Iron minerals of sedimentary rocks __ ______ 2 Hematitic iron-formation of Precambrian age__ W18 Iron oxides __ _______________________ 2 Magnetite-rich rocks of Mesozoic and Paleozoic Goethite (a-FeO (OH) ) and limonite _ 2 age___________-__-._____________ 19 Lepidocrocite (y-FeO(OH) )________ 3 Magnetite-rich iron-formation of Precambrian Hematite (a-Fe2O3) _ _ _ __ ___. _ _ 3 age._____-__---____--_---_-------------_ 21 Maghemite (7-Fe203) __ __________ 3 Silicate facies_________________________________ 21 Magnetite (Fe3O4) ________ _ ___ 3 Chamositic ironstone____--_-_-__----_-_---_- 21 3 Silicate iron-formation of Precambrian age_____ 22 Iron silicates 4 Glauconitic rocks__-_-____--------__-------- 23 4 Carbonate facies______-_-_-___-------_---------- 23 Greenalite. ________________________________ 6 Sideritic rocks of post-Precambrian age._______ 24 Glauconite____ _____________________________ 6 Sideritic iron-formation of Precambrian age____ 24 Chlorite (excluding chamosite) _______________ 7 Sulfide facies___________________________ 25 Minnesotaite.
    [Show full text]
  • Acidic Weathering of Carbonate Building Stones: Experimental Assessment (Preliminary Results)
    Studia Universitatis Babeş-Bolyai, Geologia, 2009, 54 (1), 33 – 36 Acidic weathering of carbonate building stones: experimental assessment (preliminary results) Ryszard KRYZA, Marta PRELL, Franciszek CZECHOWSKI Malgorzata DOMARADZKA University of Wroclaw, ul. Cybulskiego 30, 50-205 Poland Received February 2009; accepted April 2009 Available online June 2009 ABSTRACT. Three types of carbonate rocks, travertine, limestone, and marble have been studied to determine their selected technical parameters (water absorption, resistance to salt crystallization damage) and reaction to experimentally modelled acid rain weathering, imitating the polluted urban atmospheric conditions. The acidic agents present in the natural acid rain precipitation, H2SO4, HCl, HNO3, CH3COOH, and the mixture of these acids (“Acid mix”), were tested. The initial stages of acid weathering involve, apart from chemical dissolution, particularly intense physical detachment of rock particles (granular disintegration) significantly contributing to the total mass loss. Travertine was found to be most prone to salt crystallization damage and to acid weathering, and these features should be taken into account especially in external architectural usage of this stone in cold climate conditions and polluted urban atmosphere. Key words: building stones, travertine, limestone, marble, chemical weathering, acid rain, atmospheric pollution. INTRODUCTION (L) from Morawica (central Poland) and marble (M) from Stronie Slaskie (SW Poland). All these carbonate rocks are Carbonate rocks have been widely used as building commonly used as architectural building and ornamental stones since ancient times, e.g. in Rome and across the materials in Poland and other countries in Central Europe. whole Mediterranean. Carbonates are formed in various Travertine is a sedimentary carbonate rock, with marine and terrestrial environments; therefore, they are macroscopically distinct porosity and parallel banded composed of various amounts of matrix, biogenic and non- structure (bedding).
    [Show full text]