DOCSLIB.ORG

Temperature-Composition Relationships Between Naturally

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Temperature-Composition Relationships Between Naturally American Mineralogist, Volume 64, pages 1133-1155, 1979 Temperature-compositionrelationships between naturally occurring augite, pigeonite,and orthopyroxeneat one bar pressure MeIcoTu RoSS AND J. SrepHEhr HUBBNBR U.S. Geological Survey Reston, Virginia 22092 Abstract Natural orthopyroxene crystals containing augite exsolution lamellae were heated at one bar and controlled oxygen fugacity to determine the temperature at which orthopyroxene + augite first react to form pigeonite + melt. Pigeonite was detected by X-ray precession pho- tography. The reaction to form pigeonite is initiated at the orthopyroxene-augite boundary, probably on the augite lamellae, which are structurally similar to pigeonite and where the or- thopyroxene and augite are in chemical equilibrium. The upper temperature lirnit for the minimum stability temperature of pigeonite at one bar, determined from heating experiments on natural pyroxenes,varies from 1284"C at Mgl(Mg + )Fe):0.92 (atomic), to 90loC and 0.04. Orthopyroxene which does not contain augite exsolution lamellae, and remains unsatu- rated with respect to augite component, transforms to pigeonite at the higher temperatures of the orthopyroxene-pigeonite stability field. Partial melting accompanies formation of pigeon- ite for orthopyroxene compositions more magnesian than Mg/(Fe+Mg) : 0.55 (atomic). Introduction existenceof three pyroxenesat one bar and a particu- lar bulk composition.This work has previously The pyroxene minerals, becauseof their presence been reportedin abstractform (Rosset al., 1972; in a wide variety of igneousand metamorphicrocks, Rossand Huebner,l975a,b). are the subject of intense and continuous study by many petrologists, mineralogists,and crystallogra- The quadrilateral pyroxenes phers. An understanding of the stability fields of theseminerals in terms of temperature,pressure and Definitions chemicalcomposition is crucial to understandingthe For the purposesof this paper, we consider the crystallizationhistory of pyroxene-bearingrocks. Of "quadrilateral pyroxenes"to be augite,pigeonite, or- the seven common pyroxenes,jadeite, acmite, om- thopyroxene,and protopyroxene.The chemicalcom- phacite,aegirine-augite, augite, pigeonite, and ortho- position of these pyroxenesis given by the formula pyroxene,the last three are by far the most important M2T2O.. The M sites may contain Ca,Mg,Fe'*, as and are the particular subject of this paper. One or well as lesseramounts of Fe3*, Li, Na, Mn2*, Tia*, more of thesethree pyroxenesoccurs in many terres- Cr3*, and Al3* in natural pyroxenes.The T sitescon- trial and lunar igneous rocks and in metamorphic tain Sio*and Al'*. rocks of the pyroxene-hornfels, amphibole-gran- All augites have space-groupsymmetry C2/c. ulite, and granulite facies. Most augitesare in the compositionrange defined by In this paper we give the resultsof heating experi- the following occupancylimits of the M sites: ments at one bar on naturally-occurring ortho- (l) ca + Mg + Fe2"+ Na * Fe3*+ Al > 1.00 pyroxeneswhich contain augite exsolution lamellae. (2) l00Ca/(Ca + Mg + Fe'z*)> 20 From these experimentswe determined the temper- and aturesat which the transformation (3) 100(Ca+ Mg + Fe2*)/(Ca+ Mg + Fe2*+ Na + Fe3*+ Al) > 75 opx t augite-+ opx + augite * pigeonite+ liquid Pigeonitespossess space-group symmetry A/c, or is first observed. This temperature is equal to, or FLr/c at lower temperatures,and have M-site occu- greater than, the minirrrum temperaturefor the co- pancy fimits ot 00n.3-004X/79/ l l l 2- l l 33$02.00 l 133 I 134 ROSS AND HUEBNER: AUGITE, PIGEONITE, AND ORTHOPYROXENE (l) Ca + Mg + Fe'z*= 1.40 gaard pyroxene trend," now firmly establishedin and the geological literature, commenceswith copreci- (2) 100Ca/(Ca + Mg + Fe'*) < 20 pitation of magnesium-rich augite and ortho- Orthopyroxeneshave spacegroup symmetry Pbca pyroxene followed by coprecipitation of augite and and M-site occupancylimits of: pigeonite; the pyroxenesincrease in iron content as (l) Ca + Mg + Fe2*> 1.40 fractional crystallizationproceeds (Brown, 1957,Fig. and 2). This crystallizationtrend has also been observed such 12) l}}Ca/(Ca + Mg * Fe'z*)< 7 in numerousother volcanic and intrusive rocks, Protopyroxenehas not been found to occur natu- as BushveldComplex (Atkins, 1969)and the Hakone rally but has beensynthesized by many workers,usu- tholeiitic andesites(Nakamura and Kushiro, 1970b). ally has the compositionMgrSi'O", and has been re- Some of the most extensivepyroxene fractionation ferred to as protoenstatite.tto (1976)was the first to trends are observedin the lunar basalts(summarized prepare good single crystals of protopyroxene; the by Papike et al., 1976).Some individual pyroxene composition he synthesized is Li'ScrMgr-r*SirOu. phenocrystsin the lunar basalts are chemically and The spacegroup of Ito's phase is Pbcn, based on a structurally zoned so as to reflect the entire pyroxene full three-dimensionalcrystal structure analysis (H. crystall2ation trend, the phenocrystcores being mag- T. Evans,Jr., personalcommunication, 1977;Smyth nesium-rich pigeonite, the rims iron-rich augite and lto, 1977),which verifiesthe symmetryproposed (Boyd and Smith, l97l). by Smith (1959) on protopyroxeneof the composi- The association augite-orthopyroxene is found tion MgrSirOu. most typically in granulite-faciesmetamorphic rocks, The compositionsof pyroxenesare commonly ex- but also in some pyroxene-hornfelsand transitional pressed in terms of mole percent CarSirOu(Wo), amphibolite-granulite rocks. The chemical composi- MgrSirOu (En), and FerSirOu(Fs). The amount of tions of the coexistingpyroxenes in granulite-facies these three componentsdepends on the method of rocks having a variety of bulk compositions have normalization of the chemical formula; different been carefully describedby a number of geologists, methods can give slightly different values.To avoid including Binns (1962)on granulitesfrom the Broken inconsistenciescaused by the use of different pyrox- Hill district of New South Wales, Subramaniart ene nonns to calculate "Wo," "En," and "Fs" we (1962) on charnockitesand associatedgranulites have chosen to express"quadrilateral" pyroxene from various localities, Davidson (1968) on gran- compositionsusing the relationships ulites of the Quairading district, Western Australia, (l) [Ca]: lOOCa/(Ca* Mg + zFe) Immega and Klein (1976) on iron formation, and (2) lMgl: l00Mg/(Ca * Mg + )Fe) Rietmeijer (19'19)on iron-rich igneousrocks in Nor- and way. Coexistingorthopyroxene and augite also occur (3) [Fe] : 100Fel(Ca + Mg + )Fe) in lunar metamorphic rocks such as the Apollo 15 where Fe : Fe2** Fe3*and Ca,Mg,Fet*,and Fe'* anorthosite 15415(Stewart et al., 1972),tllLe Apollo are the numbers of cations per formula unit. For 17 troctolite 76535(Gooley et al., 1974),and the no- "quadrilateral" pyroxenesthat do not contain large ritic breccia 77215(Huebner et al., 1975).Petrogra- amounts of AlrOr, TiOr, MnO, FerOr, and NarO the phic and chemographicevidence suggests that the or- in these [Ca], [Mg], and [Fe] values are close to the values thopyroxene and augite were equilibrated Wo, En, and Fs, respectively,calculated by the vari- rocks. ous normalization methods. Equilibrium assemblagescontaining ortho- pyroxeneand pigeoniteare apparentlyquite rare, for Occurrencesin igneousand metamorphicrocks thesetwo phasesin the presenceof melt coexistonly Cooling magmas crystallize quadrilateral pyrox- over a very narrow compositional range. Virgo and enesin a generally consistentsequence of composi- Ross (1973) reported on coexisting orthopyroxene tions such that the first pyroxenesto crystallize are and pigeonitephenocrysts in Mull andesiteglass but magnesium-richand the last are iron-rich. The stud- could not demonstratetrue equilibrium relationships. ies of Wager and Deer (1939),Brown (1957),and The three-phaseassemblage orthopyroxene-pigeon- Brown and Vincent (1963) establish quantitatively ite-augite is also quite rare: basaltic or andesitic the pyroxene crystallization trend in rocks of gab- magmas are in equilibrium with three pyroxenes broic composition-specifically those of the Skaer- only over very restricted temperature-composition gaard Intrusion, East Greenland. The "Skaer- ranges.In strongly fractionatingliquids, however,the nOSS,4.ryD HUEBNER: AUGITE, PIGEONITE. AND ORTHOPYROXENE I 135 melt may intersectthe three-pyroxenefield over an appreciable temperature-compositionrange where orthopyroxene,pigeonite, augite, and melt are in re- action relation (Huebner et al., 1972).Examples of three coexistingpyroxenes have been reportedin an- desitesfrom Weiselberg,Germany and Hakone vol- cano,Japan by Nakamura and Kushiro (1970a,b). Protopyroxenehas not been reported as occurring naturally; however, evidence exists that a magne- sium-rich pigeonite ("clinoenstatite") found in por- phyritic volcanic rocks from Cape Vogel, Papua 1 (Dallwitz et al.,1966)and in the ShawL-group chon- I 1000 E (Dodd drite et al., 1975)is an inversionproduct from E high-temperatureprotopyroxene. E ,o qoo Subsolidusreactions An exampleof the subsotduspyroxene phase rela- tions is depictedin Figure l, a planar sectionthrough the pyroxene ternary phase volume, and coincident with an orthopyroxene-augitetie line. Augite and pi- geonite which coprecipitate above the three-pyrox- ene stability region and then cool slowly will unmix pigeoniteand augite,respectively. Pigeonite on cool- ing into the two-phaseaugite-orthopyroxene stabitty volume may transform to the stableassemblage aug- ite plus orthopyroxene, thereby forming
Load more

Recommended publications
  • Module 7 Igneous Rocks IGNEOUS ROCKS
    Module 7 Igneous Rocks IGNEOUS ROCKS ▪ Igneous Rocks form by crystallization of molten rock material IGNEOUS ROCKS ▪ Igneous Rocks form by crystallization of molten rock material ▪ Molten rock material below Earth’s surface is called magma ▪ Molten rock material erupted above Earth’s surface is called lava ▪ The name changes because the composition of the molten material changes as it is erupted due to escape of volatile gases Rocks Cycle Consolidation Crystallization Rock Forming Minerals 1200ºC Olivine High Ca-rich Pyroxene Ca-Na-rich Amphibole Intermediate Na-Ca-rich Continuous branch Continuous Discontinuous branch Discontinuous Biotite Na-rich Plagioclase feldspar of liquid increases liquid of 2 Temperature decreases Temperature SiO Low K-feldspar Muscovite Quartz 700ºC BOWEN’S REACTION SERIES Rock Forming Minerals Olivine Ca-rich Pyroxene Ca-Na-rich Amphibole Na-Ca-rich Continuous branch Continuous Discontinuous branch Discontinuous Biotite Na-rich Plagioclase feldspar K-feldspar Muscovite Quartz BOWEN’S REACTION SERIES Rock Forming Minerals High Temperature Mineral Suite Olivine • Isolated Tetrahedra Structure • Iron, magnesium, silicon, oxygen • Bowen’s Discontinuous Series Augite • Single Chain Structure (Pyroxene) • Iron, magnesium, calcium, silicon, aluminium, oxygen • Bowen’s Discontinuos Series Calcium Feldspar • Framework Silicate Structure (Plagioclase) • Calcium, silicon, aluminium, oxygen • Bowen’s Continuous Series Rock Forming Minerals Intermediate Temperature Mineral Suite Hornblende • Double Chain Structure (Amphibole)
    [Show full text]
  • Mid-Infrared Optical Constants of Clinopyroxene and Orthoclase Derived from Oriented Single-Crystal Reflectance Spectra
    American Mineralogist, Volume 99, pages 1942–1955, 2014 Mid-infrared optical constants of clinopyroxene and orthoclase derived from oriented single-crystal reflectance spectra JESSICA A. ARNOLD1,*, TIMOTHY D. GLOTCH1 AND ANNA M. PLONKA1 1Department of Geosciences, Stony Brook University, Stony Brook, New York 11794, U.S.A. ABSTRACT We have determined the mid-IR optical constants of one alkali feldspar and four pyroxene compo- sitions in the range of 250–4000 cm–1. Measured reflectance spectra of oriented single crystals were iteratively fit to modeled spectra derived from classical dispersion analysis. We present the real and imaginary indices of refraction (n and k) along with the oscillator parameters with which they were modeled. While materials of orthorhombic symmetry and higher are well covered by the current literature, optical constants have been derived for only a handful of geologically relevant monoclinic materials, including gypsum and orthoclase. Two input parameters that go into radiative transfer models, the scattering phase function and the single scattering albedo, are functions of a material’s optical constants. Pyroxene is a common rock-forming mineral group in terrestrial bodies as well as meteorites and is also detected in cosmic dust. Hence, having a set of pyroxene optical constants will provide additional details about the composition of Solar System bodies and circumstellar materials. We follow the method of Mayerhöfer et al. (2010), which is based on the Berreman 4 × 4 matrix formulation. This approach provides a consistent way to calculate the reflectance coefficients in low- symmetry cases. Additionally, while many models assume normal incidence to simplify the dispersion relations, this more general model applies to reflectance spectra collected at non-normal incidence.
    [Show full text]
  • Mineral Collecting Sites in North Carolina by W
    .'.' .., Mineral Collecting Sites in North Carolina By W. F. Wilson and B. J. McKenzie RUTILE GUMMITE IN GARNET RUBY CORUNDUM GOLD TORBERNITE GARNET IN MICA ANATASE RUTILE AJTUNITE AND TORBERNITE THULITE AND PYRITE MONAZITE EMERALD CUPRITE SMOKY QUARTZ ZIRCON TORBERNITE ~/ UBRAR'l USE ONLV ,~O NOT REMOVE. fROM LIBRARY N. C. GEOLOGICAL SUHVEY Information Circular 24 Mineral Collecting Sites in North Carolina By W. F. Wilson and B. J. McKenzie Raleigh 1978 Second Printing 1980. Additional copies of this publication may be obtained from: North CarOlina Department of Natural Resources and Community Development Geological Survey Section P. O. Box 27687 ~ Raleigh. N. C. 27611 1823 --~- GEOLOGICAL SURVEY SECTION The Geological Survey Section shall, by law"...make such exami­ nation, survey, and mapping of the geology, mineralogy, and topo­ graphy of the state, including their industrial and economic utilization as it may consider necessary." In carrying out its duties under this law, the section promotes the wise conservation and use of mineral resources by industry, commerce, agriculture, and other governmental agencies for the general welfare of the citizens of North Carolina. The Section conducts a number of basic and applied research projects in environmental resource planning, mineral resource explora­ tion, mineral statistics, and systematic geologic mapping. Services constitute a major portion ofthe Sections's activities and include identi­ fying rock and mineral samples submitted by the citizens of the state and providing consulting services and specially prepared reports to other agencies that require geological information. The Geological Survey Section publishes results of research in a series of Bulletins, Economic Papers, Information Circulars, Educa­ tional Series, Geologic Maps, and Special Publications.
    [Show full text]
  • PRELIMINARY EVALUATION of BEDROCK POTENTIAL for NATURALLY OCCURRING ASBESTOS in ALASKA by Diana N
    Alaska Division of Geological & Geophysical Surveys MISCELLANEOUS PUBLICATION 157 PRELIMINARY EVALUATION OF BEDROCK POTENTIAL FOR NATURALLY OCCURRING ASBESTOS IN ALASKA by Diana N. Solie and Jennifer E. Athey Tremolite (UAMES 34960) displaying the soft, friable fibers of asbestiform minerals. Sample collected from the Cosmos Hills area, Kobuk District, Alaska, by Eskil Anderson. Image courtesy of the University of Alaska Museum Earth Sciences Department. June 2015 Released by STATE OF ALASKA DEPARTMENT OF NATURAL RESOURCES Division of Geological & Geophysical Surveys 3354 College Road, Fairbanks, Alaska 99709-3707 907-451-5020 dggs.alaska.gov [email protected] $2.00 (text only) $13.00 (per map sheet) TABLE OF CONTENTS Abstract ................................................................................................................................................................................................................................. 1 Introduction ........................................................................................................................................................................................................................ 1 General geology of asbestos ......................................................................................................................................................................................... 2 Naturally occurring asbestos potential in Alaska ..............................................................................................................................................
    [Show full text]
  • Papers and Proceedings of the Royal Society of Tasmania
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by University of Tasmania Open Access Repository ON MESOZOIC DOLERITP] AND DIABASE IN TASMANIA. By W. H. Twblvetrees, F.G.S., and W. F. Petterd, C.M.Z.S. The following Notes lay no claim to be an exhaustive description of our familiar '• diabase" or "dolerite" rock, which plays such an important part in the geology and physical configuration of our Island. The present object is rather to place upon record some inferences drawn from the examination of numerous microscopical sections of speci- mens collected or received from all parts of Tasmania. It is by accumulating the results of observations that stepping stones are formed to more complete knowledge. A glance at Mr. R. M. Johnston's geological map of Tasmania, issued by the Lands Office, will show the share this rock takes in the structure of the Island. It occupies the whole upland area of the Central Tiers. On the northern face of the Tiers—the Western Tiers as they are here called—there is a tongue of the rock prolonged northwards past IMount Claude. At their north-west corner it forms or caps mountains, such as Cradle Mountain (the highest in Tas- mania), Barn Bluff, Mount Pelion West. Eldon Blufi: forms a narrow western extension. Mount Sedgwick is a western out-lier ; Mount Dundas another. In that part of the island it is also found at Mount Heemskirk Falls, and on the Magnet Range, two miles north of the Magnet Mine. Mounts Gell and Hugel are also western out-liers.
    [Show full text]
  • A Comparative Study of Jadeite, Omphacite and Kosmochlor Jades from Myanmar, and Suggestions for a Practical Nomenclature
    Feature Article A Comparative Study of Jadeite, Omphacite and Kosmochlor Jades from Myanmar, and Suggestions for a Practical Nomenclature Leander Franz, Tay Thye Sun, Henry A. Hänni, Christian de Capitani, Theerapongs Thanasuthipitak and Wilawan Atichat Jadeitite boulders from north-central Myanmar show a wide variability in texture and mineral content. This study gives an overview of the petrography of these rocks, and classiies them into ive different types: (1) jadeitites with kosmochlor and clinoamphibole, (2) jadeitites with clinoamphibole, (3) albite-bearing jadeitites, (4) almost pure jadeitites and (5) omphacitites. Their textures indicate that some of the assemblages formed syn-tectonically while those samples with decussate textures show no indication of a tectonic overprint. Backscattered electron images and electron microprobe analyses highlight the variable mineral chemistry of the samples. Their extensive chemical and textural inhomogeneity renders a classiication by common gemmological methods rather dificult. Although a deinitive classiication of such rocks is only possible using thin-section analysis, we demonstrate that a fast and non-destructive identiication as jadeite jade, kosmochlor jade or omphacite jade is possible using Raman and infrared spectroscopy, which gave results that were in accord with the microprobe analyses. Furthermore, current classiication schemes for jadeitites are reviewed. The Journal of Gemmology, 34(3), 2014, pp. 210–229, http://dx.doi.org/10.15506/JoG.2014.34.3.210 © 2014 The Gemmological Association of Great Britain Introduction simple. Jadeite jade is usually a green massive The word jade is derived from the Spanish phrase rock consisting of jadeite (NaAlSi2O6; see Ou Yang, for piedra de ijada (Foshag, 1957) or ‘loin stone’ 1999; Ou Yang and Li, 1999; Ou Yang and Qi, from its reputed use in curing ailments of the loins 2001).
    [Show full text]
  • NASA  Dr.’S Doug Stoeser & Steve Wilson, USGS  Wikipedia, 2009
    Jacqueline Graham Danielle Granlund Janet Schweizerhof Peter Rossiter Lunar Soil (regolith) is extremely-fine, dust-like material All systems that go to the Moon will interact with this material, both intentionally and unintentionally: Can it be used for construction purposes? Can it be used to grow plants? Will it affect human health? Is it detrimental to machinery, equipment, clothes, etc.? In order to colonize the Moon, it must be known how the Lunar Soil will interact with the various systems Unfortunately, the Apollo missions did not bring back enough sample to study and characterize fully Emphasis has therefore been placed on making, studying, and characterizing “simulants” such as: Minnesota Lunar Simulant (MLS-1) was developed in the 1970s and 1980s Johnson Space Center (JSC-1) in 1990’s MLS-2, JSC-1A, JSC-1F, JSC-2, JSC-3, etc. were developed later but, like the others, all were consumed in various studies International interest gains strength and a new “moon race” develops: Japan (FJS-1 and MKS-1) China (CAS-1) Previous studies were centered on using single resources of terrestrial igneous rock, predominantly from volcanic areas, with a focus on the elemental content and not necessarily the mineralogy and chemistry Most of the studies took these materials, added fluxes, heated to a molten state, allowed to solidify, and, after cooling, crushed, ground and pulverized the material Consequently, no simulant has accurately and adequately reproduced Lunar Soil Over 95% of Lunar Soil is comprised of silicates belonging
    [Show full text]
  • The Nakhlite Meteorites: Augite-Rich Igneous Rocks from Mars ARTICLE
    ARTICLE IN PRESS Chemie der Erde 65 (2005) 203–270 www.elsevier.de/chemer INVITED REVIEW The nakhlite meteorites: Augite-rich igneous rocks from Mars Allan H. Treiman Lunar and Planetary Institute, 3600 Bay Area Boulevard, Houston, TX 77058-1113, USA Received 22 October 2004; accepted 18 January 2005 Abstract The seven nakhlite meteorites are augite-rich igneous rocks that formed in flows or shallow intrusions of basaltic magma on Mars. They consist of euhedral to subhedral crystals of augite and olivine (to 1 cm long) in fine-grained mesostases. The augite crystals have homogeneous cores of Mg0 ¼ 63% and rims that are normally zoned to iron enrichment. The core–rim zoning is cut by iron-enriched zones along fractures and is replaced locally by ferroan low-Ca pyroxene. The core compositions of the olivines vary inversely with the steepness of their rim zoning – sharp rim zoning goes with the most magnesian cores (Mg0 ¼ 42%), homogeneous olivines are the most ferroan. The olivine and augite crystals contain multiphase inclusions representing trapped magma. Among the olivine and augite crystals is mesostasis, composed principally of plagioclase and/or glass, with euhedra of titanomagnetite and many minor minerals. Olivine and mesostasis glass are partially replaced by veinlets and patches of iddingsite, a mixture of smectite clays, iron oxy-hydroxides and carbonate minerals. In the mesostasis are rare patches of a salt alteration assemblage: halite, siderite, and anhydrite/ gypsum. The nakhlites are little shocked, but have been affected chemically and biologically by their residence on Earth. Differences among the chemical compositions of the nakhlites can be ascribed mostly to different proportions of augite, olivine, and mesostasis.
    [Show full text]
  • Crystallization History of Lunar F Eldspa Thic Basalt 14310
    Crystallization History of Lunar F eldspa thic Basalt 14310 GEOLOGICAL SURVEY PROFESSIONAL PAPER 841 Prepared on behalf of the National Aeronautics and Space Administration Crystallization History of Lunar F eldspa thic Basalt 14 31 0 By ODETTE B. JAMES GEOLOGICAL SURVEY PROFESSIONAL PAPER 841 Prepared on behalf of the National Aeronautics and Space Administration An account of the crystallization history of an unusual type of lunar basalt, deduced from detailed petrographic studies and microprobe mineral analyses UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1973 UNITED STATES DEPARTMENT OF THE INTERIOR ROGERS C. B. MORTON, Secretary GEOLOGICAL SURVEY V. E. McKelvey, Director Library of Congress catalog-card No. 73-600177 For sale by the Superintendent of Documents U.S. Government Printing Office Washington, D.C. 20402- Price 70 cents domestic postpaid or 50 cents GPO Bookstore Stock Number 2401-00361 CONTENTS Page Page Abstract ---------------------------------------- 1 Phase compositions-Continued Introduction ------------------------------------­ 1 Compositions of orthopyroxene and clinopyroxene 13 Mineral assemblage and texture ------------------ 2 at"their contacts --------------------------­ Pigeonite and ferropig,eonite ------------------ 14 General features ----------------------------­ 2 Augite _______ ------------------------------- 15 Locally developed fine-scale textures ----------­ 3 Compositions of pigeonite and augite at their Orthopyroxene with preserved euhedral faces 4 contacts ----------------------------------­
    [Show full text]
  • Petrography and Engineering Properties of Igneous Rocks
    ENGINEERil~G MONOGRAPHS No. I United States Department of the Interior BUREAU OF RECLAMATION PETROGRAPIIY AND ENGINEERING· PROPER11ES OF IGNEOUS ROCKS hy Rit~bard C. 1\lielenz Denver, Colorado October 1948 95 cents (R.evised September 1961) United States Department of the Interior STEWART L. UDALL, Secretacy Bureau of Reclamation FLOYD E. DOMINY, Commissioner G~T BLOODGOOD, Assistant Commissioner and Chief Engineer Engineering Monograph No. 1 PETROGRAPHY AND ENGINEERING PROPERTIRES ·OF IGNEOUS RO<;:KS by Richard C. Mielenz Revised 1959. by William Y. Holland Head. Petrographic Laboratory Section Chemical Engineering Laboratory Branch Commissioner's Office. Denver Technical Infortnation Branch Denver Federal Center Denver, Colorado ENGINEERING MONOGRAPHS are published in limited editions for the technical staff of the Bureau of Reclamation and interested technical circles in Government and private agencies. Their purpose is to record devel­ opments, innovations, .and progress in the engineering and scientific techniques and practices that are employed in the planning, design, construction, and operation of Rec­ lamation structures and equipment. Copies 'may be obtained from the Bureau of Recla- · mation, Denver Federal Center, Denver, Colon.do, and Washington, D. C. Excavation and concreting of altered zones in rhyolite dike in the spillway foundation. Davis Damsite. Arizona-Nevada. Fl'ontispiece CONTENTS Page Introduction . 1 General Basis of Classification of Rocks . 1 Relation of the Petrographic Character to the Engineering Properties of Rocks . 3 Engineering J?roperties of Igneous Rocks ................................ :. 4 Plutonic Rocks . 4 Hypabyssal Rocks . 6 Volcanic Rocks..... 7 Application of Petrography to Engineering Problems of the Bureau of Reclamation . 8 A Mineralogic and Textural Classification of Igneous Rocks .
    [Show full text]
  • Ca–Mg Diffusion in Diopside: Tracer and Chemical Inter-Diffusion Coefficients
    Contrib Mineral Petrol (2010) 159:175–186 DOI 10.1007/s00410-009-0422-5 ORIGINAL PAPER Ca–Mg diffusion in diopside: tracer and chemical inter-diffusion coefficients Xiaoyu Zhang Æ Jibamitra Ganguly Æ Motoo Ito Received: 20 March 2009 / Accepted: 8 July 2009 / Published online: 2 August 2009 Ó Springer-Verlag 2009 Abstract We have experimentally determined the tracer chemical diffusion coefficient of Ca and Mg must take into diffusion coefficients (D*) of 44Ca and 26Mg in a natural account the effect of thermodynamic factor (TF) on dif- diopside (*Di96) as function of crystallographic direction fusion coefficient. We calculate the dependence of the TF and temperature in the range of 950–1,150 °C at 1 bar and and the chemical interdiffusion coefficient, D(Ca–Mg), on f(O2) corresponding to those of the WI buffer. The exper- composition in the diopside–clinoenstatite mixture, using imental data parallel to the a*, b, and c crystallographic the available data on mixing property in this binary system. directions show significant diffusion anisotropy in the a–c Our D*(Ca) values parallel to the c axis are about 1–1.5 log and b–c planes, with the fastest diffusion being parallel units larger than those Dimanov et al. (1996). Incorporating to the c axis. With the exception of logD*(26Mg) parallel the effect of TF, the D(Ca–Mg) values calculated from our to the a* axis, the experimental data conform to the data at 1,100–1,200 °Cis*0.6–0.7 log unit greater than empirical diffusion ‘‘compensation relation’’, converging the experimental quasibinary D((Ca–Mg ? Fe)) data of to logD * -19.3 m2/s and T * 1,155 °C.
    [Show full text]
  • Volume 60, I'lum6eit , JAN /Feb Me
    OREGON GEOLOGY published by the Oregon Deportment of Geology and Mineral Industries OREGON GEOLOGY Barnett appointed to OOGAMI Governing Board --VOlUME 60, i'lUM6EIt , JAN /fEB Me... N. Barnett at Pa1Iond ho.I bMn oppoinl8d b)' c:.o... .... 10M 16tz1lo ... ."d ....1.rnMI by !he Or."", ...... ... .. -~....... " "" _..-.-- _-_._--_ - .. .. '--. S,n." lor • fOUl-year Ie!m be""'" OKombel " _"'.eI ,"7, 0$ c.c:-mIn, 1\oaI,j ".,..,w.., of ,110 Ole,,,,, -~ o.pll"",nt aI c.doC one! Mlnaol Induwles --- , ~. - (OOCoAMl) Bornoort ."a: .." John W. S\olJl~ '" _.- -_-- ..... Pa1Iond • .me....-..d two f""' - ~ _.., Ihe Go.<- --. _u_- --~- """"...... d ----______- - .. ~ ... _. ... _.>m. ......... ,... ... ........ - ---- _ 1oIoM.,.,- ... _ ,, -""'"'+ .......,0>, ... '"___ cc,.", .. _ ...' , """.~ ""1>'11 .n-, - ~- ,...,...-..... .. ,_.c:.- .......... ---__ (0'1" ''''''''_lM'I . ,. ,, ~ -,--~. " ~ -., W»o-~ _IM',_->cuo' -- .... I"",. ..... _ "'" ....... ....._ _-..., r-__.. , , ':--,--.. ,1>._ .- ..._ _.. ........ _ -...m.I>W __ .n-".., .... _"'Jr--. -",--....,-- ..._., , AriHoI It. "tftOft ,...I"-_.. ,_..,. ___ u , _ , -, ... ..... .. "' .... .............. .......... BlIlIOn Is tho M.".,. 01 1"- Humon ~ - ""-__",-_._- . ,,,._.nn_ .. _. _ __ ot _- •.. ...... OpeI.lioN 00tp0." ......1 01 PortIa..a General E~1c Company (PGEJ. $110 ".. bftn wo<ldn, .mt. P'GE oIr>e. '918. mostly ... ........,..,. /v..ctloro. ",,j _.'_'_._-""'_--~"'----"--.""-"--"'"_._- ___ ".... _ _ ' F........ p''"''''''"''"''tIy ... II>e .." af ........., RQoourcn. Silo _ .... _.. __ .. _R__ .. _• ott.odod "-PP-.... ~ one! " .....Iod hom AbiIono Chnstian 1..Wvoni1y 11\ .... Shoo 10 rrwrI.cI 0IId : -_ .. __ .. ..... two -.,..I ~... She Is .., Itw M,->, -----""'---........ .. .-_ -- CcundI 01 INS. alia, Asmy Gt-v..... .. and""- --,.-_............ -_--- 11\ IN """" ".ObtIy 01 r.
    [Show full text]