DOCSLIB.ORG

The Formation Ofatacamite During Weathering of Sulfides on the Modern Seafloor

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
The Formation Ofatacamite During Weathering of Sulfides on the Modern Seafloor 945 The Canadian M iner alngi st Vol. 31,pp. 945-956(1993) THEFORMATION OFATACAMITE DURING WEATHERING OF SULFIDES ON THEMODERN SEAFLOOR* MARKD. HANNINGTON GeologicalSurvey of Canala" 601 Booth Street,Ottawa. Ontario KIA 0E8 ABsrRAcr Atacamite tCu2C(OtI)lJ is a Qommonsecondary mineral in the oxidized portions of black smokerdeposits on the modem mid-oceanridges. Weathered s€afloor sulfides from the TAG HytlrothermalField (Mid-Atlantic fudge) contain abundantFe oxyhytlroxides,jarosite, and secondarycopper minerals. All threepo,lymorphs of CurCl(OFI)r,atacamite, paratacamite and the rare mineral botallackite,have been identlfied in samplesrecovered from the seafloorgossans at TAG. Atacamiteforms when cuprousc!:loride somplexesand Cu2* ions are releasedfrom sulfides during corrosionby acidic pore-fluids. The copperions migrate in solution througb the gossansand reprecipitateas basic cupric salts in contact with the surroundingseawater. The atacamiteand paratacamileoccur as colloform masses,crystalline aggregates,or disseminationswithin amorphousFe oxyhy- droxides,goethite, jarosite, and secondaryCu sulfides. Botallackite is presentas sparsecorroded crystals. Gibbs free-energy data for atacamiteand pamtacamiteindicate that Cu2Cl(OH)3is the most stable salt of copper in the seafloor weathering profile, and solubility calculationsshow that it is only sparingly soluble in seawater.Observations at TAG suggestthat the atac4mitein gossansoverlying the depositsmay have been presenton the seafloorfor as long as 20,000 years and possibly 40,000-50,000yeaxs. Confary to recent suggestionsin the literature, atacamitedoes not form on the modem seafloorunder hydrothermalconditions. The susceptibilityof atacamiteto hydration and dissolutionin fresh water accountsfor its absencein most surficial environmentsand precludes its long-termpreservation in the geologicalrecord. Key'vtords:atacamiig, paratacamite, botallackite, Fe oxyhydroxides,seafloor weathering, sulfide gossans,TAG hydrothermal fiel4 Mid-Atlantic Ridge. SoMtilans L'atacamite tCuzCl(OII):l est un rnin6ral secondairer6pandu dans les partiesoxyd6es des gisementsassoci6s aux fumeurs noin le long des dorsalesmddio-oc6aniques modernes. L'altdration des sulfuresdes fonds marins du champhydrothermal de TAG (dorsalem6dio-Atlantique) sontient une abondanced'oxydes de fer, de jarosite, et des min6rauxsecondaires du cuivre, Les trois polymorphesde Cu2Cl(OH)3,atacamite, pamtacamite, et memebotallackite, espOcerare, ont 6t6 identifi6s dansles dchantillonspr6lev6s des chapeauxde fer. L'atacamitese forme quandles complexeschlorurds de cuiwe (cupreux)et les ions Cu2+sont libdr6s dessulfures pendant leur corrosionpar une phasefluide tr caractdreacide. l,es ions de cuiwe se propagenten solution d travers des chapeauxde fer et forment un pr6cipitd de sels basiquescupriques au contact avec I'eau de mer ambiante.L'atacamite et Ia paratacamitese prdsententen massescolloformes, en agr6gatscristallins, ou en diss6minationsau sein de massesd'oxydes amorphesde fer, de goethite, de jarosite, et de sulfures secondairesde cuivre. La botallackite se pr6sentesous forrne de crisaux 6parscorrod6s. L,es donndes sur l'6nergie libre de formation de I'atacamite et de la para- tacamiiemontrent que Cu2Cl(OH),est la forme la plus stablede cuivre dansle milieu sous-marinprds des zonesd'alt6ration. Des calculs de solubilitd d6monfientque cos phasessont trbs peu solublesdans I'eau de mer. Les observations] TAG font penserque I'atacamitedes chapeaux de fer qui recouwentles gisementspourraient avoir 6t6 formdsil y a au moins 20,000ans, et peut€tre m6me40,000-50,000 ans. Contrairernentd une opinion 6miser6cemment daas la littdrature,l'atacamite n'est pa$ pr6cipit6edirectement sous conditions hydrothermales dans les fonds oc6aniquesmodemes. Sa susceptibilitda Cfiehy&at6e et dissoutedans I'eau fralche rend comptede son absencedans la plupart desmiJieux de surface,et expliqueson absencedans les rochesplus anciennes. (Traduit par la R6daction) Mots-cl6s: atacamite,paratacamite, botallackite, oxydes de fer, lessivagesous-marin, chapeau de fer, sulfures,champ hydrothermalde TAG, dorsalem€dio-Atlantique. * GeologrcalSurvey of Canadacontribution number 44492. Downloaded from http://pubs.geoscienceworld.org/canmin/article-pdf/31/4/945/3446737/945.pdf by guest on 01 October 2021 946 l.rrnooucrrotv few studieshave addressed the physicaland chemical conditionsunder which it forms. This paper examines In its type locality, the AtacamaDesert in the high the mineralogy, chemistry, and paragenesisof ata- Andes of northern Chile, the basic cupric chloride, camite in samples recovered from the TAG atacamite[Cu2C(OH)3], occurs in the oxidizedzones HydrothermalField on the Mid-Atlantic Ridge of exposedporphyry copperdeposits (e.9., Bandy (26'N). The sampleswere collectedby dredgingof a 1938).The rapid descentof the water table through large sulfide moundin 1985and during submersible these depositsand the onset of a sustained,hyperarid operationswith ALVIN in 1986and 1990. climate in the Miocene have resultedin the Dreser- vation of abundantsecondary copper sulfide. iulfate, OccrinnsNcpoF ATACAMTTErNTm and chloride minerals within a thick weathering Tac HynnorneRMALFEI-o profile (Mortimer 1973,Alpers & Brimhall 1988, 1989).The AtacamaDesert is now one of the driest The TAG hydrothermalfield comprisesthree large placeson tfie surfaceof the earth. In stark contrastto sulfide mounds.one active and two inactive.The this environment,atacamite also is commonlyfound activemound occurs on the floor ofthe rift valley and as a secondarymineral in the weatheredportions of is a large,steep-sided deposit measuring 200-250 m in massivesulfide depositson tfie modernseafloor. This diameter and 2040 m in height, with a vigorous paradoxowes itselfto the unique physical and chemi- central black smokercomplex and an apron of oxidiz- cal behaviorof atacamitein naturalenvironments. ing sulfide talus and metalliferousoxide sediments Atacamite was first reportedfrom the modern (Rona er al. 1986,Thompson et al. 1988,Metz et al. seafloorby Bonatti et al. (1976). They noted the 1988).Two additionalinactive sulfide depositsoccur occurrenceof secondaryatacamite in disseminated on the east wall of the rift valley and are currently and stockwork-typeveinlets of chalcopyriteexposed undergoingextensive erosion and mass-wasting (Rona in basaltic crust uplifted along fracture zones on the et al. 1990,1993).The largestsulfide depositshave Mid-Atlantic Ridge. A similar occunencewas noted been exposedto seawaterpossibly for as long as by Scott et al. (1982). The atacamitein botl cases 40,000-50,000years (Lalou et al. 1990),and parts are occurswith other secondaryCu oxide, Cu sulfide and now coveredby extensivedeposits of Fe oxy- Fe oxide minerals,and was interpretedto be a product hydroxides(up to severaltens of centimetersthick). of seafloorweathering of the chalcopyriteveins. Thesegossans resemble the weatheredcaps on many Atacamite has since been describedin weatheredsul- ancientsulfide deposits now exposedon land,and are fides from most of the known black smoker deoosits apparentlya productof similarproces$es of oxidation forming on the mid-oceanridges, and it is especially takingplace on the seafloor(e.g.,Henig et al. l99l). abundantat fossil hydrothermal sites, where sulfides Pyrite, marcasite,and chalcopyritehave been haveexperienced a long history of submarineweather- altered extensivelyto secondarymineral assemblages ing (e.g.,Hekinian & Fouquet1985, Alt et al. 1987, consistingmainly of amorphousFe oxyhydroxides, Alt 1988a,b, Embley et al. 1988,Scott e/ al. 1990, togetherwith abundantsecondary Cu sulfides,jarosite, Yankoet al. 1991).Despite the numerousdocumented atacamite,and tracesof native copperand native gold. occurrencesof atacamiteon the modern oceanfloor, The oxidizine sulfide mound containsacidic pore- Ftc. 1. Bottom photographstaken from the submersibleALVIN showing the weatheredand oxidized surface of the TAG Mound. The greenishcolor of the outcrop is due to the presenceof abundantatacamite, for which this part of the deposit hasbeen labeled the "greencliffs". Approximatefield of view is 3 metersin photo (a) and 1 meterin photo (b). Downloaded from http://pubs.geoscienceworld.org/canmin/article-pdf/31/4/945/3446737/945.pdf by guest on 01 October 2021 TI{E FORMATION OF ATACAMITE ON TIIE SEAFLOOR Frc. 2. a) Large block of massivesuLfrde from the TAG Mound, with an encrustationof emerald-greenatacamite. b) Crust of colloform atacamitewith central cavity lined by a thin film of amorphousFe oxyhydroxides.c) Cryptocrystalline,collo- form massesof atacamite.d) Euhedral rhombic prisms of atacamiteon the corroded surface of massivechalcopyrite. e) Intergrowthof atacamiteand paxatacamite(dipyramids) dusted with Fe oxyhydroxides.f) Large, blocky crystals ofbotallackite. Downloaded from http://pubs.geoscienceworld.org/canmin/article-pdf/31/4/945/3446737/945.pdf by guest on 01 October 2021 948 THE CANADIAN MINERALOGIST fluids, having pH values between3.6 and 5.5, masseson the outer surfacesof weatheredsulfide producedby the reaction of exposedpyrite and chal- blocks, (2) as crystalline aggregatesthat fill open copyrite with seawater(Hannington et al. L990). spacesin massiveFe-oxide crusts, and (3) as dissemi- Measurementsof pH and redox potential indicate that nated crystals intergrown with fine-grained Fe oxy- conditions within the oxidation profile are similar to hydroxidesor that fill open spaceswithin corroded thoseencountered in areasof acid mine-drainage.This sulfides.Atacamite
Load more

Recommended publications
  • Washington State Minerals Checklist
    Division of Geology and Earth Resources MS 47007; Olympia, WA 98504-7007 Washington State 360-902-1450; 360-902-1785 fax E-mail: [email protected] Website: http://www.dnr.wa.gov/geology Minerals Checklist Note: Mineral names in parentheses are the preferred species names. Compiled by Raymond Lasmanis o Acanthite o Arsenopalladinite o Bustamite o Clinohumite o Enstatite o Harmotome o Actinolite o Arsenopyrite o Bytownite o Clinoptilolite o Epidesmine (Stilbite) o Hastingsite o Adularia o Arsenosulvanite (Plagioclase) o Clinozoisite o Epidote o Hausmannite (Orthoclase) o Arsenpolybasite o Cairngorm (Quartz) o Cobaltite o Epistilbite o Hedenbergite o Aegirine o Astrophyllite o Calamine o Cochromite o Epsomite o Hedleyite o Aenigmatite o Atacamite (Hemimorphite) o Coffinite o Erionite o Hematite o Aeschynite o Atokite o Calaverite o Columbite o Erythrite o Hemimorphite o Agardite-Y o Augite o Calciohilairite (Ferrocolumbite) o Euchroite o Hercynite o Agate (Quartz) o Aurostibite o Calcite, see also o Conichalcite o Euxenite o Hessite o Aguilarite o Austinite Manganocalcite o Connellite o Euxenite-Y o Heulandite o Aktashite o Onyx o Copiapite o o Autunite o Fairchildite Hexahydrite o Alabandite o Caledonite o Copper o o Awaruite o Famatinite Hibschite o Albite o Cancrinite o Copper-zinc o o Axinite group o Fayalite Hillebrandite o Algodonite o Carnelian (Quartz) o Coquandite o o Azurite o Feldspar group Hisingerite o Allanite o Cassiterite o Cordierite o o Barite o Ferberite Hongshiite o Allanite-Ce o Catapleiite o Corrensite o o Bastnäsite
    [Show full text]
  • 3, Isostructural with Botallackite
    American Mineralogist, Volume 101, pages 986–990, 2016 Crystal structure of a new compound, CuZnCl(OH)3, isostructural with botallackite HEXING YANG1,*, ISABEL F. BARTON2, MARCELO B. ANDRADE1, AND ROBERT T. DOWNS1 1Department of Geosciences, University of Arizona, 1040 E. 4th Street, Tucson, Arizona 85721, U.S.A. 2Lowell Institute for Mineral Resources, University of Arizona, Tucson, Arizona 85721, U.S.A. ABSTRACT A new compound, ideally CuZnCl(OH)3, was found on a metallic mining artifact of copper composition at the Rowley mine, Maricopa County, Arizona, U.S.A., and studied with electron microprobe analysis, single-crystal X-ray diffraction, and Raman spectroscopy. It is isostructural with botallackite [Cu2Cl(OH)3] with space group P21/m and unit-cell parameters a = 5.6883(5), b = 3 6.3908(6), c = 5.5248(5) Å, β = 90.832(2)°, V = 200.82(3) Å . The crystal structure of CuZnCl(OH)3, refined to R1 = 0.018, is characterized by brucite-type octahedral sheets made of two distinct and considerably distorted octahedra, M1 and M2, which are coordinated by (5OH + 1Cl) and (4OH + 2Cl), respectively. The octahedral sheets are parallel to (100) and connected by O–H∙∙∙Cl hydrogen bonding. The major structural difference between CuZnCl(OH)3 and botallackite is the complete replacement of Cu2+ in the highly angle-distorted M1 site by non-Jahn-Teller distorting Zn2+. The CuZnCl(OH)3 compound represents the highest Zn content ever documented for the atacamite group of minerals, in conflict with all previous reports that botallackite (like atacamite) is the most 2+ resistant, of all copper hydroxylchloride Cu2Cl(OH)3 polymorphs, to the substitution of Zn for Cu2+, even in the presence of large excess of Zn2+.
    [Show full text]
  • X-Ray Study and Synthesis of Some Copper-Lead Oxychlorides
    This dissertation has been 64—7070 microfilmed exactly as received WINCHELL, Jr., Robert Eugene, 1931- X-RAY STUDY AND SYNTHESIS OF SOME COPPER-LEAD OXYCHLORIDES. The Ohio State University, Ph.D., 1963 M ineralogy University Microfilms, Inc., Ann Arbor, Michigan X-RAY STUDY AND SYNTHESIS OF SOME COPPER-LEAD OXYCHLORIDES DISSERTATION Presented in Partial Fulfillment of the Requirements for the Degree Doctor of Philosopher in the Graduate School of the Ohio State University Robert Eugene W inchell, J r ., B. S ., M. S. The Ohio State University 1963 Approved ty Id viser Department of Mineralogy ACKNOWLEDGMENTS The author wishes to acknowledge the assistance, cooperation and encouragement of a great number of people without whom this thesis could not have been completed. The specimens used in the study of these rare oxychlorides were obtained from a number of sources. Dr. C. S. Hurlbut, Jr. supplied samples of a l l the sp ecies from the c o lle c tio n s o f Harvard U n iversity. Dr. Paul E. Desautels provided additional samples of all the minerals except pseudoboleite from the collections of the United States National Museum. Dr. Raymond Hocart, of the University of Paris, supplied several overgrowths of cumengeite on boleite, which had been given to him by G. Friedel, Dr. S. Grolier, of the St. Etienne School of Mines, St. Etienne, France, provided material that had been available to G. Friedel during his study (Friedel, 1906) of boleite, pseudoboleite, and cumengeite. Dr. S. Caillere provided specimens of boleite, cumengeite and pseudoboleite from the collections of the Paris Museum of Natural History.
    [Show full text]
  • Structures of the Pseudo-Trigonal Polymorphs of Cu2(OH)3Cl
    research papers Acta Crystallographica Section B Structural Structures of the pseudo-trigonal polymorphs of Science Cu2(OH)3Cl ISSN 0108-7681 Received 2 February 2009 Thomas Malcherek* and Jochen The crystal structure of Cu2(OH)3Cl has been determined Schlu¨ter using two natural samples with almost ideal stoichiometry. Accepted 14 April 2009 While one of the samples exhibits a twinned clinoatacamite structure, the other sample is characterized by the appearance Mineralogisch-Petrographisches Institut, Univer- of additional weak diffraction maxima at half integer positions sita¨t Hamburg, Grindelallee 48, D-20146 Hamburg, Germany of h and k. Structure refinement was carried out with the space group P11. The relationship between the triclinic phase, clinoatacamite, paratacamite and the herbertsmithite struc- Correspondence e-mail: ture is discussed in terms of symmetry as a function of Cu [email protected] concentration. 1. Introduction Pure Cu2(OH)3Cl so far has been known to occur in the form of the three polymorphs atacamite, botallackite and clino- atacamite. While atacamite is orthorhombic the other two polymorphs are monoclinic. Another, rhombohedral structure type of Cu2(OH)3Cl (paratacamite) has been described by Fleet (1975), but it is now believed that the rhombohedral substructure of paratacamite has to be stabilized by partial substitution of Zn or Ni for Cu (Jambor et al., 1996) at ambient temperature. The Zn end member of such a solid solution, Cu3Zn(OH)6Cl2, has been described as the mineral herbertsmithite (Braithwaite et al., 2004). Recently Clissold et al. (2007) reported the crystal structure of gillardite, the Ni analogue of herbertsmithite.
    [Show full text]
  • Clinoailacamite, a NEW POLYMORPH of Gur(Ohl3cl, and ITS Relaflonship to PARATACAMITE and 'ANARAKITE"*
    61. Tlrc Catwdian M ineral ogi st Vol. 34, pp.6lJ2 (1996) CLINOAilACAMITE,A NEW POLYMORPHOF Gur(OHl3Cl, AND ITS RELAflONSHIPTO PARATACAMITEAND 'ANARAKITE"* JOHNL. JAMBOR Department of Earth Sciences, University of Waterlao, Waterloo, Ontario N2L 3GI JOHNE. DUTRZAC CANMET,Deparnnent of Naaral ResourcesCananq 555 Booth Street, Ottawa, Ontaria KIA OGj ANDREW C. ROBERTS GeologicalSurvey of Cananq601 Booth Street, Otawa" Owaria KIA 088 JOELD. GRICE ResearchDivisiou CatadianMuseurn of Naure, Ottatva,Ontaria KIP 6P4 JANT. SZYMA(SKI CANMET,Depamnent of NaturalResources Canad4 555 Booth Street, Ottawo" Ontario KIA 0GI ABSTRA T The new mineral clinoatacamiteis a polmorph of Cu2(OII)3C| othen are botallackite (monoclinic), atacamite(ortho- rhornbic),an{ possiblyparatacamite (rhombohedral). Clinoatacanite is monoclinic, spacegroup P21ln,a 6.157(2),b 6.814Q), c 9.104(5) A, p 99.65(4)", which is transformableto a pseudorhombohedralcell approximating that of paxatacamite. Clinoatacamitehas been found in specimensfrom severallocalities, aad coexistswith paratacamitein the holotype specimenof p,aralacamite.The two minerals are not readily distinguishedexcept by optical and X-ray methods:paratacamite is uniaxial negative, whereasclinoatacamite is biaxht negative, 2V@75(5f . Strongestlines of the X-ray powder paltern of clino- aracamireld n A(D@k[)]are 5.47(100)(T0l,0Ll),2.887(40X121J03),2.767(60)81.1),2.742Q0)(0r3,202),2.266(@)Q20), 2.243(50)(004),and L.7M(5Q82a,040). Clinoatacamiteis readily synthesizedand a seriesof experimentswas conductedto promotethe uptakeof Zn and duplicatethe formula of the dubiousmineral "anarakite" (CuZn)2(OI{)3C1.Generally, products with more than about6 mol%o"7iproved to be hexagonal,i.e., nrcranpaatacamite, as did specimensof "anarakite"fron fhe type locality.
    [Show full text]
  • Crystal Structure of a New Compound, Cuzncl(OH)3, Isostructural with Botallackite
    American Mineralogist, Volume 101, pages 986–990, 2016 Crystal structure of a new compound, CuZnCl(OH)3, isostructural with botallackite HEXING YANG1,*, ISABEL F. BARTON2, MARCELO B. ANDRADE1, AND ROBERT T. DOWNS1 1Department of Geosciences, University of Arizona, 1040 E. 4th Street, Tucson, Arizona 85721, U.S.A. 2Lowell Institute for Mineral Resources, University of Arizona, Tucson, Arizona 85721, U.S.A. ABSTRACT A new compound, ideally CuZnCl(OH)3, was found on a metallic mining artifact of copper composition at the Rowley mine, Maricopa County, Arizona, U.S.A., and studied with electron microprobe analysis, single-crystal X-ray diffraction, and Raman spectroscopy. It is isostructural with botallackite [Cu2Cl(OH)3] with space group P21/m and unit-cell parameters a = 5.6883(5), b = 3 6.3908(6), c = 5.5248(5) Å, β = 90.832(2)°, V = 200.82(3) Å . The crystal structure of CuZnCl(OH)3, refined to R1 = 0.018, is characterized by brucite-type octahedral sheets made of two distinct and considerably distorted octahedra, M1 and M2, which are coordinated by (5OH + 1Cl) and (4OH + 2Cl), respectively. The octahedral sheets are parallel to (100) and connected by O–H∙∙∙Cl hydrogen bonding. The major structural difference between CuZnCl(OH)3 and botallackite is the complete replacement of Cu2+ in the highly angle-distorted M1 site by non-Jahn-Teller distorting Zn2+. The CuZnCl(OH)3 compound represents the highest Zn content ever documented for the atacamite group of minerals, in conflict with all previous reports that botallackite (like atacamite) is the most 2+ resistant, of all copper hydroxylchloride Cu2Cl(OH)3 polymorphs, to the substitution of Zn for Cu2+, even in the presence of large excess of Zn2+.
    [Show full text]
  • Journal of the Russell Society, Vol 4 No 2
    JOURNAL OF THE RUSSELL SOCIETY The journal of British Isles topographical mineralogy EDITOR: George Ryba.:k. 42 Bell Road. Sitlingbourn.:. Kent ME 10 4EB. L.K. JOURNAL MANAGER: Rex Cook. '13 Halifax Road . Nelson, Lancashire BB9 OEQ , U.K. EDITORrAL BOARD: F.B. Atkins. Oxford, U. K. R.J. King, Tewkesbury. U.K. R.E. Bevins. Cardiff, U. K. A. Livingstone, Edinburgh, U.K. R.S.W. Brai thwaite. Manchester. U.K. I.R. Plimer, Parkvill.:. Australia T.F. Bridges. Ovington. U.K. R.E. Starkey, Brom,grove, U.K S.c. Chamberlain. Syracuse. U. S.A. R.F. Symes. London, U.K. N.J. Forley. Keyworth. U.K. P.A. Williams. Kingswood. Australia R.A. Howie. Matlock. U.K. B. Young. Newcastle, U.K. Aims and Scope: The lournal publishes articles and reviews by both amateur and profe,sional mineralogists dealing with all a,pecI, of mineralogy. Contributions concerning the topographical mineralogy of the British Isles arc particularly welcome. Not~s for contributors can be found at the back of the Journal. Subscription rates: The Journal is free to members of the Russell Society. Subsc ription rates for two issues tiS. Enquiries should be made to the Journal Manager at the above address. Back copies of the Journal may also be ordered through the Journal Ma nager. Advertising: Details of advertising rates may be obtained from the Journal Manager. Published by The Russell Society. Registered charity No. 803308. Copyright The Russell Society 1993 . ISSN 0263 7839 FRONT COVER: Strontianite, Strontian mines, Highland Region, Scotland. 100 mm x 55 mm.
    [Show full text]
  • The Crystal Structure of Clinoatacamite May Be Havethe Composition[Cu(Oidacl2] and Tcu(Ofd5clrl
    73 The Carudian M ineralo gist Vol. 34, pp.73-78(1996) THECRYSTAL STRUCTURE OF CLINOATACAMITE. A NEWPOLVMORPH OF Gu2(OH)3Cl JOELD. GRICE ResearchDivixioq CanadianMu*eam of Nature,P.O. Box 32143, Staion "D", Oxawa.Ontario KIP 6P4 JANT. SZYMANSKI CANMET,Natural ResourcesCarnda" 555Booth Street,Oxawa" Ontario KIA 0GI JOHNL. JAMBOR Depannznt of Earth Scientes,University of Waerlao, Waerloo, Ontario N2L 3Gl ABsrRAcr The crystal structureof clinoatacamite,Cul+(OtI13Cl, has beendetermined and refined to indicesft = 5.2 and wR = 4.9Vo. The strucfirreis monoclinic,spacegoup nlln(1,4),-wirhcellparametersa6.144(l), r 6.805(l), c9.Ll2(l) A, p SS.SS(:)', V 375.7(2)A3, and with Z = 4.T\e structureanalysis was essentialin determfuingthe valencestate of copper(Cu2) and the number of (OII)- anions in the formula. The structure consists of layen of partly occupid edge-sharingoctahedra of Jabn-Teller-distortedtCu(OH)4C121 octahedra parallel to (101). This layer is topologically the sameas that in mica. Adjacent layers of octahedraare offset, suchfhat vacantdites in one sheetalign with occupiedsites in the neighboringsheet Layers are linked by individual, slightly Jahn-Teller-distoriedoctahedra of composition[Cu(OH)o] . The structuresof paxatacamiteand the otherpolymorphs of Cur(OII)3CI,atacamite and botanakite, also arelayered but they differ from the layering of clinoatacamite in topology,composition and srcss-linkage. Keywords:clinoatacamite, crystal shucture,layer of ocahedr4 polymorph,Jahn-Teller distortion. SoMr{ens Nous avons affind la structurecristalline de la clinoatacamite,Cua+(OH)3CI, jusqu'i un rdsidu fi de 5.2Vo(wR = 4.9Vo). Il s'agitdhne structure6saoclinique, ^groupe spatial P21ln (14), dont les paramdtresr6ticulaires sont a 6.1,44(1),,6.805(l), c9.Il2(I) A, B 99.55(3f, V375.7(2) A3,powZ=4.
    [Show full text]
  • The Substituted Basic Cu(II) Chloride Phase Transformations
    European Mineralogical Conference Vol. 1, EMC2012-61-1, 2012 European Mineralogical Conference 2012 © Author(s) 2012 The substituted basic Cu(II) chloride phase transformations M. Sciberras (1), P. Leverett (1), P.A Williams (1), T. Malcherek (2), and J. Schlueter (2) (1) School of Science and Health, University of Western Sydney, Sydney, Australia ([email protected]), (2) Mineralogisch-Petrographisches Institut, Universität Hamburg, Hamburg, Germany ([email protected]) The known polymorphs of composition Cu2Cl(OH)3 are botallackite (P 21/m), atacamite (Pnma), clinoatacamite (P 21/n), anatacamite (P 1) and paratacamite (R3). Paratacamite was originally described by Smith (1906) as having the composition Cu2Cl(OH)3, but it is now accepted that the rhombohedral structure is stabilised by the presence of some essential Zn or Ni (Jambor et al., 1996). The structure of paratacamite was determined by Fleet (1975) assuming the nominal formula Cu2Cl(OH)3 and exhibits a pronounced sub-cell with a’ = 1/2a, c’ = c, space group R3m. It is now known that this R3mstructure is that of herbertsmithite and gillardite, Cu3MCl2(OH)6, M = Zn, Ni, respectively (Braithwaite et al., 2004; Clissold et al., 2007). A series a compositionally related phase transformations are known to occur in this group as Cu is replaced by Zn or Ni. It is suggested that the order of phase transformations follow the series, P 1 ! P 21/n ! R3 ! R3m (Malcherek and Schlüter, 1999). This series of potential transformations was explored by Raman spectroscopy for materials of composition Cu4−xMxCl2(OH)6 where M = Zn or Ni, between Cu3:90M0:10Cl2(OH)6 to Cu3:08M0:92Cl2(OH)6.
    [Show full text]
  • Nantokite Cucl C 2001-2005 Mineral Data Publishing, Version 1
    Nantokite CuCl c 2001-2005 Mineral Data Publishing, version 1 Crystal Data: Cubic. Point Group: 43m. Granular, massive. Physical Properties: Fracture: Conchoidal. Tenacity: Sectile. Hardness = 2.5 D(meas.) = 3.93–4.3; 4.136 (synthetic). D(calc.) = 4.22 Alters to paratacamite on exposure. Optical Properties: Transparent to translucent. Color: Colorless, white; grayish to greenish on exposure; colorless in transmitted light. Streak: White. Luster: Adamantine. Optical Class: Isotropic; may be anomalously anisotropic. n = 1.930(5) (synthetic). Cell Data: Space Group: F 43m. a = 5.407 Z = 4 X-ray Powder Pattern: Synthetic. 3.127 (100), 1.915 (55), 1.633 (30), 1.243 (10), 2.710 (8), 1.1054 (8), 1.354 (6) Chemistry: (1) (2) (3) Cu 64.17 64.28 64.19 Cl 35.52 35.82 35.81 Total 99.69 100.10 100.00 (1) Nantoko, Chile. (2) Broken Hill, Australia. (3) CuCl. Occurrence: A secondary mineral in hydrothermal copper-bearing deposits; rarely in volcanic sublimates. Association: Cuprite, copper, atacamite, paratacamite, claringbullite, cerussite, hematite. Distribution: In the Carmen Bajo mine, Pintada Mountain, near Nantoko, Copiap´odistrict, Atacama, Chile. From Broken Hill, New South Wales, and at the Wewak, Magpie, and Great Australia mines, Cloncurrie, Queensland, Australia. In the Malanjkhand copper deposit, north of Durg, Madhya Pradesh, India. From the Tolbachik volcano, Kamchatka Peninsula, Russia. At Dzhezkazgan, Kazakhstan. From the Levant mine, St. Just, Cornwall, England. Along Baratti Beach, Tuscany, Italy, in slag. In the USA, at Bisbee, Cochise County, Arizona, and in the Steeple Rock district, Grant Co., New Mexico. From the Ojuela mine, Mapim´ı,Durango, Mexico.
    [Show full text]
  • New Mineral Names*,†
    American Mineralogist, Volume 100, pages 2352–2362, 2015 New Mineral Names*,† DMITRIY I. BELAKOVSKIY1, FERNANDO CÁMARA2, OLIVIER C. GAGNE3 AND YULIA UVAROVA4 1Fersman Mineralogical Museum, Russian Academy of Sciences, Leninskiy Prospekt 18 korp. 2, Moscow 119071, Russia 2Dipartimento di Scienze della Terra, Universitá di degli Studi di Torino, Via Valperga Caluso, 35-10125 Torino, Italy 3Department of Geological Sciences, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada 4Mineral Resources Flagship, CSIRO, ARRC, 26 Dick Perry Avenue, Kensington, Western Australia 6151, Australia IN THIS ISSUE This New Mineral Names has entries for 18 new minerals, including aluminopyracmonite, bobmeyer- ite, hylbrownite, kihlmanite-(Ce), kleberite, leydetite, nestolaite, paratakamite-(Mg), paratacamite-(Ni), schlüterite-(Y), švenekite, tangdanite, vanadoallanite-(La), and pyrochlore supergroup species fluorcal- ciomicrolite, fluorcalcioroméite, hydroxycalciopyrochlore, oxycalcioroméite, and oxyplumboroméite. ALUMINOPYRACMONITE* Z = 6. In the crystal structure of aluminopyracmonite [refined F. Demartin, C. Castellano, and I. Campostrini (2013) Alumi- to R1 = 0.0258 for 998 unique I > 2σ(I) reflections] two types of Al octahedra are linked by corner sharing with (SO4) tetrahedra nopyracmonite, (NH4)3Al(SO4)3, a new ammonium alumin- ium sulfate from La Fossa crater, Vulcano, Aeolian Islands, with two possible conformation with 2/3 and 1/3 occupation, to Italy. Mineralogical Magazine, 77(4), 443–451. form the infinite [Al(SO4)3]∞ chains made by the AlO6 octahedra which share all their corners with sulfate tetrahedra. The voids Aluminopyracmonite (IMA 2012-075), ideally located between these parallel chains extending along [001] host the ammonium ions that are hydrogen-bonded with the (NH4)3Al(SO4)3, is a new mineral from La Fossa crater, Vul- cano, Aeolian Islands, Sicily, Italy.
    [Show full text]
  • Download Article (PDF)
    Pure Appl. Chem., Vol. 77, No. 3, pp. 643–651, 2005. DOI: 10.1351/pac200577030643 © 2005 IUPAC Solutions in the “big laboratory”: Toward a model for metals at the Earth’s surface* Peter A. Williams School of Science, Food and Horticulture, University of Western Sydney, Locked Bag 1797, Penrith South DC NSW 1797, Australia Abstract: Numerous factors control the chemistry of metal ions in natural aqueous systems. These include the presence of a host of complexing agents, speciation among a variety of competing ligands, buffering due to precipitated solid phases, and the relative influences of kinetic versus thermodynamic phenomena. Natural aqueous systems are inevitably compli- cated, but simple, inorganic models can be constructed to characterize a variety of different environments. While available data sets for these models are large, it is clear that much fur- ther research is required in order to develop more sophisticated models. Some of the fields of research that need to be addressed are outlined, and some of the constraints on such re- search are briefly discussed. Keywords: aqueous solutions; geochemistry; minerals; modeling; equilibria. INTRODUCTION We live in a watery world. The “big laboratory”, the surface of the Earth, is a heterogeneous environ- ment in which aqueous systems play a major role in determining the chemistry of transport of inorganic and organic species. Among other things, the transport of metal ions and their interactions with living organisms is mediated by aqueous chemistries of varying complexity. Understanding such systems is of central importance in many fields ranging from biochemistry, toxicology, and nutrition to hydrometal- lurgy, mineral exploration, and pollution studies [1,2].
    [Show full text]