DOCSLIB.ORG

B.Sc., Mcgill University (1953) June 1959

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text

Load more

I II_ I , - -I I - -- I --~---~C"--R~~' Ilrb*IE~CICIII _jl(-rl~~;l~TsL -- - I CHEMICAL PETROLOGY OP METAMORPHIC IRON FORMATIONS AND ASSOCIATED ROCKS IN THE MOUNT REED AREA IN NORTHERN QUEBEC by Svante Hakan Kranck B.Sc., McGill University (1953) M.Sc., McGill University (1955) FA SUBMITTED IN PARTIAL FULFILLMENT OF f REQUIPEMES FOR THE DEGREE OF DOCTOR OF PHILOSOPHY MASSACHUSETTS INSTITUTE OF TECHNOLOGY June 1959 Signature of Author Department, of Geology and Geophysics, May 18, 1959 Certified by Thesis Supervisor Accepted by , Chairman, Departmental Committee on Graduate Student 1 Room 14-0551 77 Massachusetts Avenue Cambridge, MA 02139 MITLibraries Ph: 617.253.5668 Fax: 617.253.1690 Document Services Email: [email protected] http://libraries.mit.edu/docs DISCLAIMER OF QUALITY Due to the condition of the original material, there are unavoidable flaws in this reproduction. We have made every effort possible to provide you with the best copy available. If you are dissatisfied with this product and find it unusable, please contact Document Services as soon as possible. Thank you.l The original Archival thesis is missing the Abstract page. This is the most complete version available. _ I '"*-9lf-~L-~-r-abl~pc~--- C I I - I I-1 I -~' 1 _L~I~LL ---~I-P-~--X?- (- fl~sCI~PI1 C" Irr~Ui~"-r~sbislLIII - - --- TABLE OF CONNENTS ABSTRACT . .. .. .. .. .. .. PART I I INTRODUCTION . ... .. ... .. * . .. 1 II THE SETTING OF THE IRON ORMATION . .. 2 III QUARTZ SPECULARITE IRON FORMATION . 0 0 0 3 IV QUARTZ MAGNETITE IRON FORMATION . * . 3 V THE SILICATE IRON FORMATION . VI THE CHEMICAL ANALYSES *. .* * * * . * a S * * 514 VII SIGNIFICANCE OF THE CHEMICAL ANALYSES . .. 6 VIII THE ORIGIN OF THE SILICATE IRON FORMATION * . 8 IX THE ROLE OF THE VOLATILE COMPONENTS . • . 10 X CONCLUSIONS . * * .. .. 0 . 0 14 XI ACKNOWLEDGEMENTS *. .. .* .. .. .. • . 15 PART II CHAPTERF1 INTRODUCTION . .. 16 2 FIELD WORK . .. .. * . .. 19 3 LABORATORY WORK. .. ... .. ... 20 4 THE MOUNT -REED-MOUNT WRIGHT AREA - LOCATION, ACCESSIBILITY . * . 22 5 SOME ASPECTS OF THE REGIONAL GEOLOGY . * 23 6 STRATIGRAPHY OF THE MOUNT REED AREA . 28 7 DESCRIPTION OF ROCK TYPES . .. * 31 THE GNEISSES . .* * 31 Garnet Amphibolite and Related Rocks . 36 Dolomitio Marble . 38 Qu&ttz Rock, Quartzite, Quartz-mica Schist . .. .. .. .. .. 9 ron Pormation, General Aspets .. 0 Quartz-Specularite-Iron Formation . 42 Quartz-Magnetite Iron Formation . 43 Silicate Iron Formation .. 43 8 THE SPECIMEN LOCALITIES OF THE SOUTHERN AREA . 46 9 THE SPECIMEN LOCALITIES OF THE NORTHERN AREA ... .. .. .. .. .. ... 48 10 SIGNIFICANCE OF THE CHEMICAL ANALYSES . 50 iv 11 GENERAL ASPECTS OF THE PHASE CHEMISTRY OF PYROXENES AND AMPHIBOLES . .. 56 12 CUMMINGTONITE AND ANTHOPHYLLITE . .. 58 13 HYPERSTHENE . 68 14 DIOPSIDE FERROAUGITE .. ..... 70 15 ACTINOLITE .. ... ... ... .. 75 16 THE EFFECT OF ALUMINUM, MANGANESE, AND SODIUM Manganese . ........... : . Sodium . .. ... ... ... .. 82 17 METAMORPHISM OF THE ARGILLACEOUS ROCKS 8 18 THE ROLE OF THE VOLATILE COMPONENTS IN METAMORPHISM ..... ... .. 85 19 THE ROLE OF THE VOLATILE COMPONENTS IN THE MOUNT REED IRON FORMATIONS .. 87 20 THE METHOD OF ESCAPE OF VOLATILE COMPONENTS DURING METAMORPHIC REACTIONS .. ... • . • • • . • o 96 21 ORIGIN OF THE IRON FORMATIONS .... 99 22 THE METAMORPHIC HISTORY OF THE IRON FORMATIONS . .. ... .... .103 23 SUMMARY AND CONCLUSIONS . .112 24 ACKNOWLEDGEMENTS . ... .116 APPENDIX A ROCKS .,AFIC.. .... .117 B IRON FORMATION - SOUTHERN AREA .. .122 C IRON FORMATION - NORTHERN AREA .. .133 D LIST OF CUMMINGTONITE ANALYSES .. .138 LIST OF ILLUSTRATIONS Fig. 1 Map showing location of the Mount Reed - Mount Wright area..*. ,4 *S4..... 9.0.... 24 Fig. 2 Map showing main features of the geology of the Mount Reed area.......,.,.....,..,...... ........... 27 Fig. 3 Diagram showing FeO-MgO-Ca0 ratios in analysed sil- icates of the Mount Reed area.......,......... .... ,52 Fig, 4 Diagram showig Fe0-Mg1O-Ca0 ratios in coexisting aflphiboles and pyroxenes,..,........ ................... 53 Fig. 5 Diagram showing the assumed position of the cum- mingtonite-anthophyllite two-phase field,,,..,.,,.....59 Fig. 6 Diagram showing compositions of analysed antho- phyllites and c nningtonites-grunerites.,..9, 4.......9 Fig. 7 Hypothetical phase diagrams showing possible stability relationships of cunmingtonite and Fig. 8 anthophyllite...................,.................0.0*0 Fig. 9 Hypothetical phase diagrams showing alternative phase relationships in the system 3FeO,MgO-SiO2 - 00 2 -H20 at the point at which minnesotaite be- comes unstable in the presence of siderite. The diagrams show phases in equilibrium with quartz........ 6 4 Fig. 10 Hypothetical phase diagrams showing how the system (Fe,Mg)O-SiO -H0-COr may change in the tempera- ture range withn which siderite and ummningtonite become unstable.....,,...,..............,....... 65 Fig. 11 Hypothetical phase diagram showing the phases that can be expected to form by the reaction of dolomite with quartz at different MgO/FeO ratios...................................0...... ... ,74 Fig, 12 Hypothetical phase diagram showing how the sta- bility relationships in the system 3Mg0,CaO- 3FeO,CaO plus excess silica may change with activity of water.. .................................7 Fig. 13 Hypothetical phase diagrani showing a section of the system FeO-MgO*Ca0-C0 2 -8i for a fixed temperature, pressure, and activity of oxygen. The diagram shows phases in equilibrium with quartz....... ............. * ..... ......... ............. 89 II ___ __i_____ _L __ _ _ _I _ s _ _ Fig, 14 Hypothetical phase diagram showing a section of the system PeO-MgO-CaO-SiO0 for a fixed temperature, pressure, and aSo vlty of CO The diagram shows ptmases in equilibrium wth quartz............... o....... ... , o..... .. ........ ,.89 Pig, 35 Hypothetical phase diagram showing a section of the system PeO-MgO-CaO-O±-S10 for a fixed temperature, pressure, 2 and letivity of *20. The diagram shows phases in equili- bri:' with quart ........................... ,.... .... 89 Fig. 16 Hypothetical phase diagrams showing possible changes in minera. tability relationships with increasing metamorphism in the PeO- MgO-CaO-HO-CO 2 systeI.,.........,..... ,..........107- 111. vii PART I I INVRODUCTION The Mount Reed area is located at the south end of the Labrador Trough about 150 miles north-northwest of Seven Islands, Quebec. The area is underlain by high-grade meta- morphic rocks mainly of semtary origin, including iron formation and dolomitic marble. In this paper are presented the results of a study of the phase equilibria among the silicate minerals in the iron formatlon, mainly ferrohyper sthene, ferroaugite, and ormingtonite. The study is based on chemlcal analyses of coexisting mlnerals. The writer had opportunity to spen three smers in the Mount Reed area In the employ of the Quebec Cartier Mining Company and through the cooperation of the comany was able to collect spemens for the qheeial study. The chemical analyses were performed at the Department of Geology of Massachusetts Institute of Technology using the rapid sili- cate analysis methods developed by Shapiro and Brannock (1956) of the United States Geological Survey. Hih-grade metamorphic iron formations have been described earlier mainly from Minnesota and Sweden. The Iron forma- tions at the eastern part of the Mesabi range have been 1 L----~--rr----- -- E~hlY1- osntaot metaorhosed by the Duluth gabbro with the development of pyoxen ind grunorite. These rooks have been doearibed in pa1ps by Grout and Broderick (1919), rout (1919), and Richars (1929) In Sweden the so- called oulysite probably are of similar origin as the siliate iron formation here described. orks on eulysite inol ud paprs by Palogron (1916), von cokrm (1922), Cartent (1924), Sundius (1924) Geijer (1925), Linroth (1926), and Tilley (1936). The Mtunt Reed sill ate iron foration differ from the oulysite and the metamorphi rocks of the' Mesab R e by the abs en oft fayalite and by the abundan of ferrohyper- atheoe and caloite. The mineral assemblages of the Mount Reed area inslude the assoeiation quartz-fetrrohyperthene- ferraugite-ommingtoni te-alcite. The assemblage is inter- eating both becausefatthe assooiation hyperthee-oalcite, so far unknown in geological literature (Rambeg 1952 page 154), and because the low varince of the assemablae indlates that the rooks in the course of the reional meta rphism were elo*ed to the volatile components 110 and C02. II THE SETTING OF THE IRON FORMATION The iron formation in the Mount Reed area is exposed mainly along the axial traces of loclinal synlines which have been zrftlded along trancsurrent fold axes. lhe thick- heas Of the iron formation is in the order of 200 feet when not thike ned or stretehed as ,aresult of the deformation It is underlain by quartzite and marble and an unknown thickness of biotite-muscovite-igmatite-gneiss. Another thick sequence of gneiss overlies the iron formation. The regional geology is described in more detail elsewhere (Kranck 1959). The field work disclosed three different facies of iron formation, namely, quartz-specularite iron formation, quartz- magnetite iron formation, and quartz-silicate iron formnation. Most of the presently commercial ore deposits are located in the first mentioned type. Transitional facies between specu- larite and the magtite iron formation on one hand and the magnetite and silicate iron formation on the other hand are common. III QUARTZ SPfCUIJARITE IRON FORMATION The quartz-apecularite iron formation is best developed
Recommended publications
  • AMPHIBOLES: Crystal Chemistry, Occurrence, and Health Issues

    AMPHIBOLES: Crystal Chemistry, Occurrence, and Health Issues

    AMPHIBOLES: Crystal Chemistry, Occurrence, and Health Issues 67 Reviews in Mineralogy and. Geochemistry 67 TABLE OF CONTENTS 1 Amphiboles: Crystal Chemistry Frank C. Hawthorne, Roberta Oberti INTRODUCTION 1 CHEMICAL FORMULA 1 SOMi : ASPECTS OF CHEMICAL ANALYSIS 1 Chemical composition 1 Summary 6 CALCULATION OF THE CHEMICAL FORMULA 7 24 (O, OH, F, CI) 7 23 (O) 8 13 cations 8 15 cations 8 16 cations 8 Summary 8 AMPIIIBOI I S: CRYSTAL STRUCTURE 8 Space groups 9 Cell dimensions 9 Site nomenclature 9 The C2/m amphibole structure 10 The P2/m amphibole structure 12 The P2/a amphibole structure 12 The Pnma amphibole structure 12 The Pnmn amphibole structure 14 The C1 amphibole structure 17 STACKING SEQUENCES AND SPACE GROUPS 18 BOND LENGTHS AND BOND VALENCES IN [4IA1-FREE AMPHIBOLES 19 THE DOUBLE-CHAIN OF TETRAHEDRA IN [4IA1 AMPHIBOLES 19 Variation in <T-0> bondlengths in C2/m amphiboles 21 Variation in <T-0> bondlengths in Pnma amphiboles 25 THE STEREOCHEMISTRY OF THE STRIP OF OCTAHEDRA 27 The C2/m amphiboles: variation in mean bondlengths 27 The Pnma amphiboles with B(Mg,Fe,Mn): variation in mean bondlengths 30 v Amphiboles - Table of Contents The Pnma amphiboles with BLi: variation in mean bondlengths 32 THE STEREOCHEMISTRY OF THE M (4) SITE 34 The calcic, sodic-calcic and sodic amphiboles 35 Amphiboles with small B cations (magnesium-iron-manganese- lithium, magnesium-sodium and lithium-sodium) 36 The C2/m amphiboles: variation in <M(4)-0> bondlengths 36 The Pnma amphiboles: variation in <MA-0> bondlengths 36 I III! STEREOCHEMISTRY OF THE A SITE 37 The C2/m amphiboles 37 The PU a amphibole 40 The Pnma amphiboles 40 The Pnmn amphiboles 41 THE STEREOCHEMISTRY OF THE 0(3) SITE 41 The C2/m amphiboles 41 UNIT-CELL PARAMETERS AND COMPOSITION IN C2/m AMPHIBOLES 42 SUMMARY 46 ACKNOWLEDGMENTS 46 REFERENCES 47 APPENDIX 1: CRYSTAL-STRUCTURE REFINEMENTS OF AMPHIBOLE 51 Z Classification of the Amphiboles Frank C.
  • The Oxidation Ratio of Iron in Coexisting Biotite And

    The Oxidation Ratio of Iron in Coexisting Biotite And

    1423 The Canadian Mineralo gist Vol.37. pp. 1423-1429(1999\ THE OXIDATIONRATIO OF IRON IN COEXISTINGBIOTITE AND HORNBLENDEFROM GRANITICAND METAMORPHICROCKS: THE ROLE OF P, T AND f(O2) NADINES. BORODINA, GERMAN B. FERSHTATER$erro SERGEI L. VOTYAKOV Institute of Geology and Geochemistry, RussianAcademy of Sciences,Pochtoty per., 7, Eknterinburg, 620151, Russia Assrnecr Previously published and new data on the composition of coexisting biotite and homblende from granitic and metamorphic rocks show that the degree of iron oxidation, R [= Fe3*/(Fe2*+ Fe3*)], is different in these two minerals; the R of hornblende is greater. Granulite-facies minerals have the greatest difference in R, whereas in granitic rocks, those minerals show the least difference The oxidation of biotite and hornblende under high-level conditions is accompaniedby the crystallization of magnet- ite, and newly formed oxidized mafic minerals have a lower Fe/(Fe + Mg) and R than the original ones. Under mesozonal and catazonalconditions, the increasein pressureprevents the formation of magnetite, and oxidation is accompaniedby a significant increase in R; these changes in the chemical composition of hornblende are supplementedby an increase in Al. Since the Al content of homblende is known to be an indicator of pressure, such a correlation of R and Fer+ content with aluminum content points to an increaseof theseparameters with a rise of pressure Keywords:biotite, hornblende,oxidation ratio, granitic rocks, metamorphic rocks, epizonal plutons, mesozonalplutons , cat^7'onal plutons. Sorravarnr, Les donn6esnouvelles et celles tirde de la litt6rature portant sur 1acomposition de la biotite et celle de la hornblendecoexistante des roches granitiques et m6tamorphiquesmontrent qui le degrd d'oxydation du fer, R [= Fe3*/(Fe2*+ Fe3+)],est diffdrent dans ces deux mindraux.
  • The Geological Newsletter

    The Geological Newsletter

    JAN 90 THE GEOLOGICAL NEWSLETTER ·• GEOLOGICAL SOCIETY OF THE OREGON COUNTRY GEOLOGICAL SOCIETY Non-Profit Org. U.S. POSTAGE OF THE OREGON COUNTRY PAID P.O. BOX ?a 7- Portland, Oregon PORTLAND, OR 97207- -:· ·--~··, Permit No. 999 - -- '~ Dr. Frank Boersma 120 W. 33~d Street Vancouver, WA 98660 GEOLOGICAL SOCIETY OF THE OREGOt\ COllNTRY 1989-1990 ADMINISTRATION BOARD OF DIRECTORS President Directors Rosemary Kenney 221-0757 Peter E. Baer (3 years) 661-7995 4211 S\-1 Condor Charlene Holzwarth (2 years) 284-3444 Portland, OR 97201 Esther Kennedy (1 year) 287-3091 Vice President Margaret L. Steere 246-1670 Immediate Past Presidents Joline Robustelli 223-2852 6929 SW 34 Ave. ~ Portland, OR 97219 R.E. (Andy) Corcoran 244-5605 Secretary Alta B. Fosback 641-6323 THE GEOLOGICAL NEWSLETTER 8942 SW Fairview Place Tigard, OR 97223 Editor: Sandra Anderson 775-5538 Treasurer Calendar: Margaret Steere 246-1670 Braden Pillow 659-6318 Business Manager: Carol Cole 220-0078 19562 SE Cottonwood St. Assist: Cecelia Crater 235-5158 Milwaukie, OR 97267 ACTIVITIES CHAIRS Calligrapher Properties and PA System Wallace R.· McClung 637-3834 (Luncheon) Donald Botteron 245-6251 Field Trips (Evening) Walter A. Sunderland 625-6840 Charlene Holzwarth 284-3444 Publications Alta B. Fosback 641-6323 Geneva E. Reddekopp 654-9818 Geology Seminars Publicity Donald D. Barr 246-2785 Roberta L. Walter 235-3579 Historian Refreshments Phyllis G. Bonebrake 289-8597 (Friday Evening) Hospitality David and Marvel Gillespie 246-2368 254-0135 (Luncheon) Margaret Fink 289-0188 Harold and Patricia Gay Moore (Evening) Maxine Harrington 297-ll86 (Geology Seminars) Catherine Evenson 654-2636 Library: Esther Kennedy 287-3091 ' ' Betty Turner 246-3192 Telephone n Past Presidents Panel Jean L.
  • Devonian and Carboniferous Metamorphism in West-Central

    Devonian and Carboniferous Metamorphism in West-Central

    American Mineralogist, Volume 73, pages20-47, 1988 Devonian and Carboniferousmetamorphism in west-centralMaine: The muscovite-almandinegeobarometer and the staurolite problem revisited M. J. Hololwlv Department of Geological Sciences,Southern Methodist University, Dallas, Texas 75275, U.S.A. B. L. Durnow Department of Geology, Louisiana State University, Baton Rouge, Louisiana 70803, U.S.A. R. W. HrNroN* The EnricoFermi Institute, The Universityof Chicago,Chicago, Illinois 60637,U.S.A. ABSTRAcT Important thermal metamorphic eventsin west-centralMaine occurred at 400 Ma (Mr), 394-379Ma(Mr), and325 Ma(Mr). EachiscloselyassociatedwithemplacementofS-type granites,such that the isogradpatterns produced in the surrounding pelitic schistsgenerally follow plutonic outlines. From north to south, gradeof metamorphism varies from chlorite to sillimanite-K-feldspar-muscovite. Mineral-chemistry studies on M, and M, indicate the following: (l) Much staurolite- grade chlorite is retrograde as demonstrated by the lack of a consistent relation between biotite composition and presenceor absenceofchlorite, given the restricted range ofX"ro allowed in these reduced graphitic rocks. Consequently,the first sillimanite-forming re- action for many pelitic schists in Maine does not involve chlorite. (2) Garnet zoning patterns are prograde in rocks of the staurolite zone and retrograde in rocks of higher grade. (3) Presenceof graphite and nearly pure ilmenite suggestslow Fe3* in micas and allows for end-membercalculations that include a "Ti biotite" (KTiD(Fe,Mg)AlSi3Oro(OH)r) and a "Ti muscovite" (KTi(Fe,Mg)AlSi3O,o(OH)r).(4) Staurolire contains about 3 H (48- oxygen basis) and shows subtle indications of nonideality in Fe-Mg Ko relationships. Garnet-biotite geothermometryindicates the following averagetemperatures for the first occurrenceof minerals:staurolite-510'C, sillimanite-580 "C, sillimanite-K-feldspar- 660 "C.
  • Lafayette - 800 Grams Nakhlite

    Lafayette - 800 Grams Nakhlite

    Lafayette - 800 grams Nakhlite Figure 1. Photograph showing fine ablation features Figure 2. Photograph of bottom surface of Lafayette of fusion crust on Lafayette meteorite. Sample is meteorite. Photograph from Field Museum Natural shaped like a truncated cone. This is a view of the top History, Chicago, number 62918. of the cone. Sample is 4-5 centimeters across. Photo- graph from Field Museum Natural History, Chicago, number 62913. Introduction According to Graham et al. (1985), “a mass of about 800 grams was noticed by Farrington in 1931 in the geological collections in Purdue University in Lafayette Indiana.” It was first described by Nininger (1935) and Mason (1962). Lafayette is very similar to the Nakhla and Governador Valadares meteorites, but apparently distinct from them (Berkley et al. 1980). Lafayette is a single stone with a fusion crust showing Figure 3. Side view of Lafayette. Photograph from well-developed flow features from ablation in the Field Museum Natural History, Chicago, number Earth’s atmosphere (figures 1,2,3). The specimen is 62917. shaped like a rounded cone with a blunt bottom end. It was apparently oriented during entry into the Earth’s that the water released during stepwise heating of atmosphere. Note that the fine ablation features seen Lafayette was enriched in deuterium. The alteration on Lafayette have not been reported on any of the assemblages in Lafayette continue to be an active field Nakhla specimens. of research, because it has been shown that the alteration in Lafayette occurred on Mars. Karlsson et al. (1992) found that Lafayette contained the most extra-terrestrial water of any Martian Lafayette is 1.32 b.y.
  • Depositional Setting of Algoma-Type Banded Iron Formation Blandine Gourcerol, P Thurston, D Kontak, O Côté-Mantha, J Biczok

    Depositional Setting of Algoma-Type Banded Iron Formation Blandine Gourcerol, P Thurston, D Kontak, O Côté-Mantha, J Biczok

    Depositional Setting of Algoma-type Banded Iron Formation Blandine Gourcerol, P Thurston, D Kontak, O Côté-Mantha, J Biczok To cite this version: Blandine Gourcerol, P Thurston, D Kontak, O Côté-Mantha, J Biczok. Depositional Setting of Algoma-type Banded Iron Formation. Precambrian Research, Elsevier, 2016. hal-02283951 HAL Id: hal-02283951 https://hal-brgm.archives-ouvertes.fr/hal-02283951 Submitted on 11 Sep 2019 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Accepted Manuscript Depositional Setting of Algoma-type Banded Iron Formation B. Gourcerol, P.C. Thurston, D.J. Kontak, O. Côté-Mantha, J. Biczok PII: S0301-9268(16)30108-5 DOI: http://dx.doi.org/10.1016/j.precamres.2016.04.019 Reference: PRECAM 4501 To appear in: Precambrian Research Received Date: 26 September 2015 Revised Date: 21 January 2016 Accepted Date: 30 April 2016 Please cite this article as: B. Gourcerol, P.C. Thurston, D.J. Kontak, O. Côté-Mantha, J. Biczok, Depositional Setting of Algoma-type Banded Iron Formation, Precambrian Research (2016), doi: http://dx.doi.org/10.1016/j.precamres. 2016.04.019 This is a PDF file of an unedited manuscript that has been accepted for publication.
  • Mineralogy and Paragenesis of Amphiboles from Gibson Peak Pluton

    Mineralogy and Paragenesis of Amphiboles from Gibson Peak Pluton

    THE AIVIERICAN MINERALOGIST, VOL. 49, SEPTEMBER-OCTOBER. 1964 MINERALOGY AND PARAGENESIS OF AMPHIBOLES FROM GIBSON PEAK PLUTON. NORTHERN CALIFORNIA PBrBn W. Lrelrlx, U. S. Geotogi,calSurvey, Denaer,Colorad,o. Ansrnacr Ixrnooucrrow Gibson Peak pluton, a 3-squaremile compositeintrusion in the Trin- itv Aips of northern california, is particularly suitablefor investigation of relations between amphibole paragenesisand igneouscrystallization becauseseveral distinctive amphiboles are important constituents of geneticallyrelated rocks that range from gabbro to trondhjemitic tona- lite. This paper describesthe sequenceof amphibole crystallization in difierent parts of the intrusion and reiates the compositionsof three newly analyzedamphiboles to crystallizationsequence and composition of the enclosingrock. The main conclusionis that compositionsof the investigatedamphiboles are as dependenton time of crystallizationwithin their respectiverocks as on bulk rock composition. Pnrnocn.q.pnrcrNtrnpnBTATroN oF THE Alrpnrsolr panecnNpsrs The generalstructural and petrologicfeatures of Gibson peak pluton are describedelsewhere (Lipman, 1963),and onl1-relations bearing on the origin of the amphibolesare summarizedhere. The pluton is com- posite,and five discreteintrusive units have beenrecognized on the basis of field relations.rn order of intrusion theseare hypersthene-hornblende gabbro, (augite-)hornblendegabbro, hornblende diorite, porphyritic quartz-bearingdiorite, and trondhjemitic biotite tonalite. All units show intrusive contacts with the preceding rocks, are petrographically dis- tinctive, and contain at least one amphibole. An interpretation of th" peak complex paragenesisof the Gibson amphiboles,based mainly on the textural featuresdescribed below, is presentedin Fig. 1. The evi- denceis clear orr the occurrenceof the indicated reactions,but the rela- 1321 PETER W. LIPMAN I I I F I I F I 1 I I cd d l :d d9 z z t.i r F-] {Fl z z.zt- z .=l il.
  • Chemographic Exploration of Amphibole Assemblages from Central Massachusetts and Southwestern New Hampshire

    Chemographic Exploration of Amphibole Assemblages from Central Massachusetts and Southwestern New Hampshire

    Mineral. Soc. Amer, Spec. Pap. 2, 251-274 (1969). CHEMOGRAPHIC EXPLORATION OF AMPHIBOLE ASSEMBLAGES FROM CENTRAL MASSACHUSETTS AND SOUTHWESTERN NEW HAMPSHIRE PETER ROBINSON AND HOWARD W. JAFFE Department of Geology, University of Massachusetts, Amherst, Massachusetts 01002 ABSTRACT Fourteen wet chemical and forty electron-probe analyses were made of amphiboles from critical assemblages in the kyanite and sillimanite zones of central Massachusetts and southwestern New Hampshire. The rocks studied in- clude plagioclase amphibolites that are metamorphosed mafic lavas and tuffs, aluminous anthophyllite rocks of uncertain derivation, quartz-garnet-amphibole granulites that are metamorphosed ferruginous cherts, and pods of ultramafic amphibolite. The rocks contain the following associations: hornblende-anthophyllite, hornblende-cummingtonite, anthophyllite-cummingtonite, hornblende-anthophyllite-cummingtonite, anthophyllite-cordierite, and anthophyllite- kyanite-sillimanite-staurolite_garnet. The following generalizations are made: 1) The cummingtonites are compositionally simple, containing neither sig- nificant AI/AI, NaJAI, nor Ca substitution. 2) The hornblendes are high in AI/AI substitution. Those coexisting with cummingtonite in the kyanite zone or in retrograded rocks have a higher Al content than those coexisting with cum- mingtonite in the sillimanite zone, in close agreement with the prograde reaction tschermakitic hornblende -7 cumming- tonite + plagioclase + H20 proposed by Shido. The Na content of hornblende is considerably less than that of the theoretical edenite end member and is relatively insensitive to variation in the Na content of coexisting plagioclase. 3) Anthophyllites coexisting with hornblende contain about 1as much AI/AI substitution and 1as much Na substitution as coexisting hornblendes. Ca is negligible. Anthophyllites with cordierite, aluminosilicates, or garnet equal or surpass hornblende in AI/AI and Na substitution.
  • Expedition 330 Core Descriptions, Site U1374 Thin Sections

    Expedition 330 Core Descriptions, Site U1374 Thin Sections

    Site U1374 thin sections U1374A-3R-1-W 114_116 Proc. IODP THIN SECTION: 330-U1374A-3R-1-W 114_116-BILLET 114-SLIDE 114 Piece No: Unit:I OBSERVER:THIN SECTION:SLIDE 114 Site U1374 core descriptions ROCK NAME: moderately olivine-phyric basalt clast WHERE SAMPLED: clast type 2 GRAINSIZE: fine grained TEXTURE: moderately phyric | Volume 330 PRIMARY PERCENT REL. VOL. SIZE(mm) VESICLE VESICLE MINERALOGY ORIGINAL REPLACED min. max. mode. MORPHOLOGY SPHERICITY Infilling [%] COMMENTS PHENOCRYSTS 10 olivine 5 20 8 1.2 skeletal incomplete dome face (iddingsite); "skeletal olivine" & "euhedral to subhedral" MICROPHENOCRYST plagioclase 0.01 0.3 0.4 laths[330] just 2 grains olivine 4 40 0.9 0.4 skeletal incomplete dome face (iddingsite); "skeletal olivine" & "euhedral to subhedral" augite 1 0.3 0.3 subhedral sector-zoning titanaugite VESICLES 3 0.1 1.8 0.6 low[330] 100 filled by calcite GROUNDMASS 87 opaque mineral 5 olivine 4 95 0.09 0.06 subhedral to replaced by iddingsite (hematite?) anhedral[330] glass 68 100 palagonite augite 1 anhedral plagioclase 9 0.2 0.01 microlite[330] SECONDARY SIZE(mm) MINERALOGY min. max. mode. REPLACING/FILLING COMMENTS calcite vesicle STRUCTURE no structure in groundmass COMMENTS SUMMARY DESCRIPTION Thin sections 1 U1374A-3R-2-W 7_9 Proc. IODP THIN SECTION: 330-U1374A-3R-2-W 7_9-BILLET 115-SLIDE 115 Piece No: Unit:I OBSERVER:THIN SECTION:SLIDE 115 Site U1374 core descriptions ROCK NAME: highly olivine-phyric basalt clast WHERE SAMPLED: CLAST TYPE 1 GRAINSIZE: fine grained TEXTURE: highly phyric & glomeroporphyritic | Volume 330 PRIMARY PERCENT REL.
  • Aqueous Alteration of Yamato 000749 Based on Multi-Probe Microscopic Observation

    Aqueous Alteration of Yamato 000749 Based on Multi-Probe Microscopic Observation

    Aqueous alteration of Yamato 000749 based on multi-probe microscopic observation Naoki Shiraishi1, Hiroki Suga1,2, Masaaki Miyahara1, Takuji Ohigashi3, Yuichi Inagaki3, Akira Yamaguchi4, Naotaka Tomioka 5, Yu Kodama6, and Eiji Ohtani7 1Hiroshima University, 2The University of Tokyo, 3UVSOR synchrotron facility, 4NIPR, 5Kochi Institute for Core Sample 6 7 Research, JAMSTEC, Marine Works Japan, Tohoku University Motivation Based on the results of Mars explorations and researches of Martian meteorites for many years, there is a high possibility that liquid water had existed extensively on Mars for a long time (Sekine, 2012). Martian meteorite is one of the important clues for restoring the past Martian surface environment that cannot be unveiled by Mars surface survey alone. It is expected that a member of Martian meteorites, nakhlites have evidences for a rock-fluid reaction occurred on Mars. One of the representative evidence for the rock-fluid reaction is “iddingsite”, which is an alteration texture formed in and around olivine grains in nakhlites. Many kinds of secondary minerals occur in the iddingsite through the rock-fluid reaction. The mineral assemblages, chemical compositions and chemical species of the secondary minerals depend on the varied parameters such as temperature and pH of the fluid. Suga et al. (2017) described the secondary minerals in the iddingsite of nakhlites Yamato (Y) 000593. Another Martian meteorites, Yamato (Y) 000749 is also a member of Yamato 00 nakhlites like Y 000593, containing abundant iddingsite. Based on Cohen et al. (2017), Y 000749 was located at the lower portion of the same nakhlites source compared to Y 000593. It is likely that these nakhlites have different mode of alteration even in the same source.
  • Miissbauer Spectra of Minnesotaite and Ferroan Talc J.M.D. Corv, T

    Miissbauer Spectra of Minnesotaite and Ferroan Talc J.M.D. Corv, T

    American Mineralogist, Volume 76, pages 1905-1909, 1991 Miissbauer spectra of minnesotaite and ferroan talc J.M.D. Corv, T. Blxls* Department of Pure and Applied Physics,Trinity College,Dublin 2, Ireland S. GuccnNnprnr Department of Geological Sciences,University of Illinois at Chicago, Chicago,Illinois 60680, U.S.A, Arsrru.cr Mdssbauer spectra of five samples of minnesotaite and one of ferroan talc have been recordedat 296 K and 4.2 K. A singleferrous doublet with isomer shift 6 : 1.13 mm/s relative to aFe and quadrupolesplitting L:2J4 mm/s is observedin all minnesotaite samples at room temperature. The ferroan talc has a smaller quadrupole splitting, A : 2.55 mm/s. All minnesotaite samplesorder antiferromagnetically,with N6el points in the tange 25-37 K, but ferroan talc does not order magnetically down to 4.2 K. Two distinct ferrous populations in minnesotaite are inferred from the resolved magneticallysplit spec- tra at 4.2 K. The minority sites may be those coordinated by the excessOH in the min- nesotaitestructure. The P-cell and C-cell variants have distinctly different hyperfine fields (10.4 and 14.9T for the two sitesin the P cell but 8.9 and 14.4T in the C cell),although their N6el points are similar. INrnooucrroN taite, ferroan talc, and talc and found a lack of compo- Minnesotaite was originally considered by Gruner sitions having the octahedralFe fraction in the range0.45- (1944) to be an Fe analogueof talc having ideal formula 0.60, perhapsindicating the chemical limits of the struc- tures. {Fel*}[Sio]O,o(OH),,where { } and [ ] denotethe oc- tahedral and tetrahedral sites, respectively.More recent- Both minnesotaite and talc have a continuous octahe- ly, X-ray and electron diffraction studies (Guggenheim dral sheet(Fe in minnesotaite, Fe,Mg in ferroan talc) but and Bailey, 1982; Guggenheim and Eggleton, 1986) differ in the nature ofthe tetrahedral sheets.It is therefore showed that the structure is considerablymore complex.
  • Alkalic Rocks of Iron Hill Gunnison County, Colorado

    Alkalic Rocks of Iron Hill Gunnison County, Colorado

    If yon do not need this publication after it has served your purpose, please return it to the Geological Survey, using the official mailing label at the end UNITED STATES DEPARTMENT OF THE INTERIOR ALKALIC ROCKS OF IRON HILL GUNNISON COUNTY, COLORADO GEOLOGICAL SURVEY PROFESSIONAL PAPER 197-A UNITED STATES DEPARTMENT OF THE INTERIOR Harold L. Ickes, Secretary GEOLOGICAL SURVEY W. C. Mendenhall, Director Professional Paper 197-A ALKALIC ROCKS OF IRON HILL GUNNISON COUNTY, COLORADO BY ESPER S. LARSEN Shorter contributions to general geology, 1941 (Pages 1-64) UNITED STATES GOVERNMENT PRINTING OFFICE WASHINGTON : 1942 For sale by the Superintendent of Documents, Washington, D. C. ......... Price 40 cents CONTENTS Page Preface, by G. F. Loughlin_________________________ v Other dike rocks_______________-____________________ 29 Abstract____"_--__-___--__________________________ 1 Augite syenite and shonkinite ____.__--___--__--__ 29 Introduction. ______________________________________ 1 Olivine gabbro. ________________________________ 30 Location and topography. _______________________ 1 Carbonate veins_________----__---------__--_---___- 31 Field work and acknowledgments.________________ 2 Character __ __________________________________ 31 Geology of the surrounding area__________________ 2 Origin _______ _ ____ _ __ _.. __ __. ___ .__. 31 Age of the Iron Hill stock_____________________ 2 Hydrothermal processes- ______--_-___-_---_--__-___- 31 General geology of the Iron Hill stock _____________ 3 The hydrothermal products. _____________________