DOCSLIB.ORG

Y4(Mg,Fe)(Si2o7)2F2, a New Mineral in a Pegmatite at Souri Valley, Komono, Mie Prefecture, Central Japan

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Y4(Mg,Fe)(Si2o7)2F2, a New Mineral in a Pegmatite at Souri Valley, Komono, Mie Prefecture, Central Japan Journal of Mineralogical and Petrological Sciences, Volume 109, page 109–117, 2014 Magnesiorowlandite–(Y), Y4(Mg,Fe)(Si2O7)2F2, a new mineral in a pegmatite at Souri Valley, Komono, Mie Prefecture, central Japan Satoshi MATSUBARA*, Ritsuro MIYAWAKI*, Kazumi YOKOYAMA*, Masako SHIGEOKA*, Koichi MOMMA* and Sadaoki YAMAMOTO** *Department of Geology and Paleontology, National Museum of Nature and Science, 4–1–1 Amakubo, Tsukuba, Ibaraki 305–0005, Japan **Obiracho, Yokkaichi, Mie 512–0921, Japan Magnesiorowlandite, Y4(Mg,Fe)(Si2O7)2F2,aMg–analogue of rowlandite–(Y), was found in a pegmatite at Souri Valley, Komono, Mie Prefecture, central Japan. The mineral occurs as aggregates composed of gray massive and white powdery parts. The aggregates are up to 1 cm in diameter scattered in the pegmatite. The mineral is associated with quartz, albite, K–feldspar, muscovite, allanite–(Ce), gadolinite–(Y), and ‘yftisite–(Y)’. It is transparent and gray to white in color with a vitreous to oily luster. The streak is white and cleavage is not observed. The Mohs hardness is 5 to 5½. The calculated density is 4.82 g/cm3. It is biaxial negative and re- fractive indices are α = 1.755 (5) and γ = 1.760 (5) with non–pleochroism. Electron microprobe (WDS) analysis gave SiO2 28.61, FeO 2.94, MnO 0.35, MgO 2.77, CaO 0.03, Y2O3 36.02, La2O3 0.29, Ce2O3 2.64, Pr2O3 0.64, Nd2O3 4.72, Sm2O3 2.82, Gd2O3 4.45, Tb2O3 0.69, Dy2O3 4.87, Ho2O3 0.50, Er2O3 1.64, Tm2O3 0.34, Yb2O3 2.02, Lu2O3 0.69, ThO2 0.24, F 4.56, –F2=O 1.92, total 99.91 wt% (average of 16 analyses), and led to the empirical formula, (Y2.71Nd0.24Dy0.22Gd0.21Ce0.14Sm0.14Yb0.09Er0.07Pr0.03Tb0.03Lu0.03Ho0.02Tm0.02La0.01Ca0.01 Th0.01)∑3.98(Mg0.58Fe0.35Mn0.04)∑0.97Si4.00O13.97F2.03 on the basis of O + F = 16. The mineral is triclinic, P1, a = 6.527(6), b = 8.656(9), c = 5.519(5) Å, α = 99.09(8), β = 104.17(7), γ = 91.48(8)°, V = 297.9(5) Å3,Z=1.It is non–metamict, and the strongest lines in the powder XRD pattern [d(Å) (I/I0) hkl] are 4.95 (33) 110; 3.64 (37) 021 ; 3.54 (38) 111 ; 3.08 (100) 201 , 021; 2.92 (26) 211, 210; 2.68 (32) 112; 2.65 (26) 130 , 012 , 002; 2.63 (28) 220. The crystal structure was determined and refined to R1 = 0.0736 for 1645 reflections with I >2σ(I)of single crystal XRD data. In the crystal structure, the Si2O7 group, together with (Mg,Fe)O4F2 octahedron, connects the 7–coordinated and 8–coordinated REEs polyhedra to form the 3–dimensional structure. Keywords: Magnesiorowlandite–(Y), New mineral, Pegmatite, Souri Valley, Komono INTRODUCTION in metamict state. Later, Shipovalov and Stepanov (1971) described crystalline rowlandite–(Y) from Kazakhstan The pegmatites at Souri Valley and in the surrounding with a triclinic cell dimension, but they did not report area are one of the famous gadolinite–(Y) localities in any structure data. As the Mg–analogue from Souri Val- Japan. During mineralogical surveys by the last author ley is non–metamict giving sharp reflections in X–ray dif- (S.Y.), an unfamiliar mineral in a pegmatite was noted. fraction studies, we were able to determine the crystal The chemical and X–ray diffraction studies indicated that structure without any heating treatments. the mineral is a Mg–analogue of rowlandite–(Y). The The Mg–analogue of rowlandite–(Y) from Souri original rowlandite–(Y), which was described from Bar- Valley is named as magnesiorowlandite–(Y) for its chem- ringer Hill, Texas, USA (Hidden, 1891), and the mineral ical relation to rowlandite–(Y), Y4FeSi4O14F2. The min- subsequently found from the Kola Peninsula Russia, are eral data and the name have been approved by the Com- mission on New Minerals, Nomenclature and Classi- doi:10.2465/jmps.131126 fication of the International Mineralogical Association R. Miyawaki, [email protected] Corresponding author (no. 2012–010). The type specimen is deposited at the 110 S. Matsubara, R. Miyawaki, K. Yokoyama, M. Shigeoka, K. Momma and S. Yamamoto National Museum of Nature and Science, Japan, under Table 1. Chemical composition of magnesiorowlandite–(Y) the registered number NSM–M43624. OCCURRENCE Magnesiorowlandite–(Y) was found in a pegmatite block that was a part of debris washed out from talus in Souri Valley located in Komono, Mie Prefecture, central Japan (Lat. 35°0′35′′ N, Long. 136°27′33′′ E). The upper zone of the valley is developed by the Cretaceous Suzuka granite, and includes many pegmatites (Harayama et al., 1989). The pegmatite minerals are mainly composed of quartz, albite, K–feldspar, and muscovite, together with accessory minerals such as allanite–(Ce), gadolinite–(Y), and ‘yftisite–(Y)’. A large crystal of thalénite–(Y) was also found in another pegmatite block in this valley. Magnesiorowlandite–(Y) occurs as aggregates com- posed of massive gray and powdery white components. The aggregates are up to 1 cm in diameter and are scat- tered in the pegmatite (Fig. 1). The massive gray part resembles thalénite–(Y). PHYSICAL AND OPTICAL PROPERTIES Magnesiorowlandite–(Y)isgraytowhitewithwhite streak. It is transparent and the luster is vitreous to oily. Cleavage is not observed and fracture is uneven. The te- nacity is brittle. The density could not be measured di- robe analysis. The powder X–ray diffraction pattern for rectly because of the small grain size. The calculated den- non–heated magnesiorowlandite–(Y) was obtained using sity is 4.82 g/cm3 on the basis of the empirical formula a Gandolfi camera, 114.6 mm in diameter, employing Ni– and refined unit cell dimensions. The Mohs hardness is 5 filtered CuKα radiation. The data were recorded on an to 5½. The mineral is biaxial negative and refractive in- imaging plate (IP), and were processed with a Fuji BAS– dices are α = 1.755 (5) and γ = 1.760 (5) with non–pleo- 2500 bio–image analyzer using a computer program writ- chroism. ten by Nakamuta (1999). The X–ray diffraction pattern (Table 2) is basically identical with those of raw and heat- CHEMICAL COMPOSITION ed samples of rowlandite–(Y). The reflections of powder X–ray diffraction pattern were indexed by reference to the Chemical analyses were carried out with a JEOL JXA– single crystal X–ray diffraction data. The unit cell param- 8800M WDS electron microprobe analyzer (15 kV, 20 eters of the triclinic system were refined with an internal nA, beam diameter 1 µm). The averaged values for 16 Si–standard reference material (NBS #640b) using a com- analyses and standard materials are shown in Table 1. puter program by Toraya (1993); a = 6.555(12), b = The empirical formula is (Y2.71Nd0.24Dy0.22Gd0.21Ce0.14 8.65(2), c = 5.530(14) Å, α = 99.3(3), β = 104.14(19), 3 Sm0.14Yb0.09Er0.07Pr0.03Tb0.03Lu0.03Ho0.02Tm0.02La0.01Ca0.01 γ = 91.4(2)°, and V = 299.4(12) Å . These values are Th0.01)∑3.98(Mg0.58Fe0.35Mn0.04)∑0.97Si4.00O13.97F2.03 on comparable to those refined from the single crystal X– the basis of O + F = 16. The simplified formula is ray diffraction data (Table 3). Y4(Mg,Fe)Si4O14F2. The single crystal X–ray diffraction data were ob- tained with the same fragment on a Rigaku AFC–7R dif- X–RAY CRYSTALLOGRAPHY fractometer using graphite–monochromatized MoKα ra- diation. Experimental details of the data collection pro- X–ray diffraction investigations were carried out with a cedure are given in Table 3. The triclinic space group fragment of small size (0.07 × 0.03 × 0.01 mm) that was symmetry of P1 was suggested by the single crystal X– 2 picked from the thin section used for the electron microp- ray diffraction data. Data reduction to Fo with Lorentz Magnesiorowlandite–(Y) from Mie Prefecture, central Japan 111 Figure 1. Photographs of the type specimen of magnesiorowlandite– (Y) in a pegmatite. (a) Shows the whole specimen with a white rec- tangle marking the area where a photomicrograph was taken. The positions of aggregate of magne- siorowlandite–(Y) are indicated by red arrows. (b) Shows a photomi- crograph of the lamella texture of massive gray and powdery white components. (a) (b) (c) (d) Figure 2. VESTA (Momma and Izumi, 2011) illustrations of the crystal structure of magnesiorowlandite–(Y). Sites are indicated by colors as follows: green for Mg, blue for Si, yellow for Y1, pink for Y2, red for O, and purple for F. (a) Chains of (Mg,Fe)O4F2 octahedra and diortho Si2O7 groups flattened into a sheet parallel to (110). (b) Stacking sequence of the alternating sheets of (Mg,Fe)O4F2 octahedra–diortho Si2O7 and of two different Y polyhedra. (c) Coordination of the larger Y1 cation with 6 O and 2 F anions. (d) Coordination of the smaller Y2 cation with 7 O anions. and polarization corrections and correction for absorption positions of Y, Mg, Si, and some O and F atoms were (φ–scan procedure) were carried out with a computer pro- determined, and those of the other O and F atoms were gram by Dr. Kazumasa Sugiyama of Tohoku University found in the difference Fourier map after the refinements (pers. communication, 2000). The crystal structure was (SHELXL–97: Sheldrick, 2008). The scattering factors analyzed using the direct method with the Patterson cal- for the neutral atoms and anomalous dispersion factors culation by means of SHELXS–97 (Sheldrick, 2008). The were taken from the International Tables for X–ray Crys- 112 S.
Load more

Recommended publications
  • Economic Geology Resources of the Llano Uplift Region
    Economic Geology Resources of the Llano Uplift Region and the Historical Impacts to the Region’s Growth Guidebook to the Texas Section- American Institute of Professional Geologists Spring Field Trip, Llano Uplift Region, Central Texas: May 14-15, 2016 Rima Petrossian, Ph.D., P.G., C.P.G.: Author and Field-Trip Organizer Renee Ryan, P.G., C.P.G.: Author and Field-Trip Leader Chris Caran, P.G.: Author and Field Guide, Los Almagres Mine Michael Jacobs, P.G., Field Trip Organizer Michael D. Campbell, P.G., P.H., C.P.G.: Author and Field-Trip Organizer Martin Meinshausen: Field Guide, Voca Sand Mine Neyda Maymi: Field Guide, Voca Sand Mine © 2016 Version 2.2 Acknowledgements A big thank you goes to the Stotts Family for allowing us exclusive access to Los Almagres mine site at Packsaddle Mountain. Also, a special thanks to Premier Silica for access to the Hickory Sands Mine and for sponsoring lunch. 2 | Page Field Trip Schedule, May 14-15, 2016 Friday Evening: Optional Friday happy hour/no-host dinner: 6 PM Evening at River City Grille, Marble Falls, Texas. Saturday Morning: 0730 hrs. Stop 1: Meet at Historical Marker Roadside Park, FM1431 westbound about 1.85 miles from Hwy 281 across from Town Mountain Granite Mine on the north side of the road for breakfast tacos (provided). Distribute for signature and return the AIPG Indemnification Document, and hand out field-trip guide; discuss geology and historical importance of groundwater and granite to Llano Uplift area (Ryan, Wise, Jacobs, etc., 30 minutes) Depart first stop in caravan east 1.85 miles to Hwy 281 and FM 1431 west intersection, turn south or right.
    [Show full text]
  • ALLANITE from BARRINGER HILL, LLANO COUNTY, TEXAS* Joun
    ALLANITE FROM BARRINGER HILL, LLANO COUNTY, TEXAS* JouN Purxart Mennlo, LIni,ted,States IVati.onal Mwseum, Washington, D.C. AesrnA.ct Allanite from Barringer Hill, Llanc County, Texas, has been analyzed, with especial attention to the "lead-ratio " The resulting value, 0.428, indicates either a large accumula- tion of "common" lead or extensive alteration. A cornplete analysis, petrographic studies, and other data are given. The pegmatites of Barringer Hill, Llano County, Texas, have yielded many specimensof radioactive minerals, a number of which have been analyzed with especialattention to the "lead-ratio." This work has been summarizedby A. Holmes (1931)and (1937),so detailedreferences and discussionneed not be given here.It shouldbe pointed out that only one mineral from this locality, an uraninite analyzed by Hillebrand and by Mackintosh, yielded a "lead-ratio" that was completely acceptable to Holmes. Most of the other minerals thus analyzed mackintoshite, yttrocrasite (from Burnet County), thorogummite, yttrialite and fer- gusonite,-he considered either to be in the metamict condition or to be alteration products. fn the early studiesof the "lead-ratio" method of geologic time determination, the varying results obtained from the analyses of Barringer Hill minerals were used to discredit the method temporarily, though, as Holmes has shown, part of the difficulty has since been removed by the discovery of the correct r6le of thorium as a radioactiveelement in the production of iead. No correctionsfor "com- mon" lead have been applied to any of the work, as in some casesnot enough material for isotope studies was available, and most of the work was done before the need for this correction was realized.
    [Show full text]
  • Zircon, Monazite and Other Minerals Used in the Production of Chemical Com- Pounds Employed in the Manufac- Ture of Lighting Apparatus
    North Carolina State Library GIFT OF \*J.^. M «v* Digitized by the Internet Archive in 2013 http://archive.org/details/zirconmonaziteot25prat V C*> ttonh Carolina Stat© ^vtef <^ Raleigh NORTH CAROLINA GEOLOGICAL AND ECONOMIC SURVEY JOSEPH HYDE PRATT, State Geologist BULLETIN No. 25 Zircon, Monazite and Other Minerals Used in the Production of Chemical Com- pounds Employed in the Manufac- ture of Lighting Apparatus BY JOSEPH HYDE PRATT, Ph.D. Raleigh, N. 0. Edwards & Broughton Printing Co. State Printers and Binders 1916 GEOLOGICAL BOARD Governor Locke Craig, ex officio chairman Raleigh Frank R. Hewitt Asheville Hugh MacRae Wilmington Henry E. Fries ". Winston-Salem John Sprunt Hill Durham Joseph Hyde Pratt, State Geologist Chapel Hill ^5 LETTER OF TRANSMITTAL Chapel Hill, M". C, October 1, 1915. To His Excellency , Honorable Locke Craig, Governor of North Carolina. Sir :—I have the honor to submit herewith for publication as Bulletin 25 a report on Zircon, Monazite and other Minerals Used in the Pro- duction of Chemical Compounds Employed in the Manufacture of Light- ing Apparatus. There is a renewed interest in the deposits of these min- erals in North Carolina, and the present report takes up not only a description of the localities in which these minerals are found, but is a technical review of the development of the lighting industry. Very truly yours, Joseph Hyde Pratt, State Geologist. ±o 5 ,3 3 2 7 CONTENTS PAGE Introduction 7 Zircon 7 Sources of Zirconia 10 Zircon 10 Baddeleyite 10 Other Zirconia-bearing Minerals 11 Occurrences and localities of Zircon 13 Zircon from Henderson County, N.
    [Show full text]
  • New Data on Yttrocrasite from the Clear Creek Pegmatite, Burnet
    American Mineralogist, Volume 62, pages 1009-10ll, 1977 Newdata on yttrocrasite from the Clear Creek pegmatite, Burnet County, Texas Wrr-soNW. Cnoor, III Departmentof Geologyand Mineralogy The Uniuersityof Michigan A nn A rbor, Michigan49 I 09 Abstract X-ray diffraction data for non-metamictyttrocrasite from the Clear Creek pegmatite, BurnetCounty, Texas,shows it to be orthorhombic,space group Pbcn, a = 12.862(7),b : 4.810(2),c : 4.571(3)A, V = 282.79As. The mineralis biaxial(-) witha = 2.131(2),4= 2.137(2),y : 2.A2(2),2V,: 60-70'.The strongestdiffraction lines are 2.147(100X600), 6.455(90X200),4.331(90X110), and 3.121(30)(310).The calculatedformula, based on ABr(O,OH)6. is (Yo..orREo.1a1Tho.116l.JoorrMno oorCao ,0nPb' o0r)(Ti1.636Feo o"2Wo ourTao oor)j(Or.ous OHor*).X-ray, optical, and chemicalanalysis suggests that ytirocrasiteis the titanium-rich 'nd-member of the euxenitegroup of rare-earthmultiple oxides. Introduction fergusonite and cyrtolite intergrown within biotite plates.Three distinct crystalswere found, megascop- Yttrocrasite, an oxide of titanium, thorium, and ically distinguishablefrom the other rare-earthspe- the yttrium-group rare earthswas discoveredby Hid- by their color (green-brown) and their shape den and Warren in 1906. The original description cies (orthorhombic-dipyramidal). included an incompletewet chemical analysisand a few physical properties.The type locality, a granite Physical properties pegmatitetwo miles eastof the famous BarringerHill rare-earthpegmatite, was inundated during the con- Yttrocrasite occurs as prismatic crystalswith ob- structionof Lake Buchananin 1936.Additional data servedforms {100},{010}, and {001}.Fracture is un- on yttrocrasite have not been obtained becauseof even to subconchoidal,and there is no observable the combination of scarcityof material and its char- cleavage.The color is green-brown and the crystals acteristicmetamict state.
    [Show full text]
  • Pegmatite Genesis: State of the Art
    Eur. J. Mineral. 2008, 20, 421–438 Published online August 2008 Paper presented at the symposium “Granitic Pagmatites: the State of the Art”, Porto, May 2007 Pegmatite genesis: state of the art Wm. B. “Skip” SIMMONS* and Karen L. WEBBER Department of Earth and Environmental Sciences, University of New Orleans, New Orleans, LA 70148, USA *Corresponding author, e-mail: [email protected] Abstract: No one universally accepted model of pegmatite genesis has yet emerged that satisfactorily explains all the diverse features of granitic pegmatites. Genesis from residual melts derived from the crystallization of granitic plutons is favoured by most researchers. Incompatible components, fluxes, volatiles and rare elements, are enriched in the residual melts. The presence of fluxes and volatiles, which lower the crystallization temperature, decrease nucleation rates, melt polymerization and viscosity, and increase diffusion rates and solubility, are considered to be critical to the development of large crystals. A number of new concepts have shed light on problems related to pegmatite genesis. Cooling rates calculated from thermal cooling models demonstrate that shallow-level pegmatites cool radically more rapidly than previously believed. Rapid cooling rates for pegmatites represent a quantum shift from the widely held view that the large crystals found in pegmatites are the result of very slow rates of cooling and crystal growth. Experimental and field evidence both suggest that undercooling and disequilibrium crystallization dominate pegmatite crys- tallization. London’s constitutional zone refining model of pegmatite evolution involves disequilibrium crystallization from an undercooled, flux-bearing granitic melt. The melt is not necessarily flux–rich and the model does not require the presence of an aqueous vapor phase.
    [Show full text]
  • A Study of the Ages of the Precambrian of Texas
    JOURNALOF GEOPHYSICALRESEARCH VOLUME67. NO. 10 SEPTEMBElt1962 A Study of the Ages of the Precambrian of Texas G. J. W•sssa•us• California Institute o[ Technology,Pasadena G. W. Institute o/Geophysicsand Departme•t o• Geology University o• California at Los Angeles L. T. SILVER California Institute o[ Technology,Pasadena P. T. FLAWN Bureau o[ EconomicGeology, University o/ Texas Abstract. Age determinationsusing the SrS7-RbS7,Ar4ø-K4ø, and Pb-U methodswere made on samplesof muscovite,biotite, amphibole,microcline, and zirconfrom igneousand meta- morphicrocks from the Franklin Mountains,Hueco Mountains,Pump Station Hills, and Carrizo and Van Horn Mountains. In addition ageswere determinedon a number of base- ment cores from Texas and New Mexico. The results show that a belt of rocks of varied lithologyextending from E1 Pasoto east of the Llano uplift are all of the sameage. The general age by the strontium and argon methodsis 1000 to 1090 m.y.; and by the lead- uranium method on zirconsit is 1150 to 1200 m.y. This event is in the same time band as the 'Grenville' orogenyin Canadaand the northeasternUnited States and possiblyshould be consideredpart of the general 'Grenville' episode.All the data now available indicate that the orogenicevent at about 1000to 1200m.y. is the mostwidespread and pervasiveepi- sodeof Precambrianorogeny on the North Americancontinent for which adequateevidence has been presented.At least one and probably two older periodsof igneousactivity and metamorphismoccurring at 1250 and 1400 m.y. are found in the northern regionsof the Texas Precambrian basement. No evidence was found for any igneous event between the early Paleozoicand the 1000-m.y.episode.
    [Show full text]
  • Uranium Industry Annual 1996
    DOE/EIA-0478(96) Distribution Category UC-950 Uranium Industry Annual 1996 April 1997 Energy Information Administration Office of Coal, Nuclear, Electric and Alternate Fuels U.S. Department of Energy Washington, DC 20585 This report was prepared by the Energy Information Administration, the independent statistical and analytical agency within the Department of Energy. The information contained herein should not be construed as advocating or reflecting any policy position of the Department of Energy or any other organization. Contacts This report was prepared by the Energy Information Ad- Exploration, production, employment, and marketing ac- ministration (EIA), Office of Coal, Nuclear, Electric and tivities: Alternate Fuels. General information about this document may be obtained from the National Energy Information Douglas Bonnar on (202) 426-1249; Center (202/586-8800), or John C. Geidl (202/426-1200), or email address: [email protected] Director of the Office of Coal, Nuclear, Electric and Al- ternate Fuels, and Robert M. Schnapp (202/426-1211), Feature article, reserves and resources: Director of the Analysis and Systems Division. Technical information about this report may be obtained from Dr. Z. Taesin Chung on (202) 426-1128; D. Nikodem (202/426-1179), Chief of the Nuclear Fuel or email address: [email protected] Cycle Branch. Survey methodology and operations: Specific questions regarding the various sections of the report should be addressed to the following staff person- Charles Johnson on (202) 426-1178; nel and/or section authors: or email address: [email protected]. ii Energy Information Adminstration/ Uranium Industry Annual 1996 Preface The Uranium Industry Annual 1996 (UIA 1996) provides (1) the country of origin and the seller of any current statistical data on the U.S.
    [Show full text]
  • Geology and Mineralogy This Document Consists of 20 Pages* Series A*
    Geology and Mineralogy This document consists of 20 pages* Series A* OF THE H!EEHIOK GEOLOGICAL SURVEY URAHIUM A5B TEORIUM H THE ACCESSORY ALLAHITE OF IGHEOUS ROCKS* By William Lee Smith, Mona L. Franck, and Alexander M. Sherwood March 1956 Trace Elements Investigations Report 398 This preliminary report is distribut without editorial-and technical revi for conformity with official standatf and nomenclature. It is not for pubH GEOLOGICAL SURVEY inspection or quotation, DENVtR, COLO *This report concerns work done on behalf of the Division of Research of the U» S» Atomic Energy Commission* USGS - Distribution (Series A) go, of copies Atomic Energy Cbjmnission, Washington ...........*......*...... 2 Division of Raw Materials, Albuquerque ....................... 1 Division of I?aw Materials, Austin ............................ 1 Division of Raw Materials, Butte ............................. 1 Division of Raw Materials, Casper ..........o................. 1 Division of Raw Materials, Denver ............................ 1 Division of Raw Materials, Ishpeming ......................... 1 Division of Raw Materials, Phoenix ........................... 1 Division of Raw Materials, Rapid City ........................ 1 Division of Raw Materials, St. George ............o........... 1 Division of Raw Jfeterials, Salt Lake City ....... ? ............ 1 Division of Raw Materials, Washington ........................ 3 Division of Research, Washington ............................. 1 Exploration Division, Grand Junction Operations Office ....... 1 Grand
    [Show full text]
  • University of Texas Bulletin No
    TEXAS UNIV. BUR. OF ECON. GEOLOGY PUBLICATION (BULL.) 1814 8291-818-2 m University of Texas Bulletin No. 1814: March 5, 1918 Chemical Analyses of Texas Rocks and Minerals By E. P. Schoch BUREAU OF ECONOMIC GEOLOGY AND TECHNOLOGY J. A. UDDEN, Director BIVISIOH OF CHEMISTRY E. P. SCHOCH, Head of the Division PUBLISHED BY THE UNIVERSITY SIX TIMES A MONTH. AND ENTERED AS SECOND»CLASS MATTER AT THE POSTOFFICE AT AUSTIN. TEXAS. UNDER THE ACT OF AUGUST 24. 1912 KEY FOR USE OF THIS PUBLICATION. The table of Contents gives the general headings under which the analyzed materials are classified, together with the numbers under which the samples and their analyses are recorded and the numbers of the pages in Part 1 and Part 2 respectively on which the data for these analyses appear. Part 1 states the sources etc. of the samples, arranged in alphabetical order of the counties in which they were obtained. Each topic in Part 1 opens with a statement of general infor- mation on such —matters as the occurrence of the analyzed ma- terial in Texas, the relation between— the composition of the material and its economic value, etc. Part 2 gives the analyses proper in the order of the analysis numbers. To find the analysis of —any particular material from any particular county in Texas,- First, look through the Table of Contents for the heading under which the material is given; and note the corresponding page number in Part 1 (for later use, note also the corre- sponding page number in Part 2) ; Second, turn to this page in Part 1, and by following the counties in their alphabetical order, find the county desired, and note the different parts of the county from which samples were obtained ; Third, after selecting a particular analysis, note its number and turn to Part 2 for the same number to secure the analysis proper (the approximate page number for this last reference was obtained before from the Table of Contents.) Table of Contents Page Key for Use of this Publication 1 INTRODUCTION Origin and Purpose of this Publication .
    [Show full text]
  • A LOOK at PEGMATITE CLASSIFICATIONS Skip Simmons Department of Geology and Geophysics, University of New Orleans, New Orleans, Louisiana 70148 USA
    A LOOK AT PEGMATITE CLASSIFICATIONS Skip Simmons Department of Geology and Geophysics, University of New Orleans, New Orleans, Louisiana 70148 USA Modern pegmatite classification schemes are strongly influenced by the depth-zone classification of granitic rocks published by Buddington (1959), and the Ginsburg et al. (1979) classification which categorized pegmatites according to their depth of emplacement and relationship to metamorphism and granitic plutons. Černý’s (1991) revision of that classification scheme (Table 1) is the most widely used classification of pegmatites today. His classification is a combination of depth of emplacement, metamorphic grade and minor element content. His 1991 classification has 4 main categories or Classes. These are Abyssal (high grade, high to low pressure), Muscovite (high pressure, lower temperature), Rare-Element (low temperature and pressure), and Miarolitic (shallow level). The Rare-Element Classes are subdivided based on composition into LCT and NYF types: LCT for Lithium, Cesium, and Tantalum enrichment and NYF for Niobium, Yttrium, and Fluorine enrichment. The Rare-Element Class is further subdivided into types and subtypes according to the mineralogical / geochemical characteristics as shown in Table 2. This scheme has been used in most modern pegmatite studies. Many pegmatites fall nicely into these categories, but during the last decade various investigations have revealed pegmatites that don’t fit into these categories. Most notably pegmatites of the NYF affiliation have required a more detailed classification as more studies revealed a greater diversity of NYF-type pegmatites. One problem is the classification of some pegmatites as NYF that contain little or no yttrium or others that contain little or no niobium.
    [Show full text]
  • Allanite from Yosemite National Park, Tuolumne Co., California C
    ALLANITE FROM YOSEMITE NATIONAL PARK, TUOLUMNE CO., CALIFORNIA C. OseonxnHurrow, Stanford.(Jniaersity, ColiJornia. Assrnecr PnnvrousWonr Allanite has been describedfrom yosemite Nationar park and ad- jacent countryby Ries(1900), pabst (1928,193g), Calkins (1930), and others,but sofar as the writer is awareneither analyses nor opticaldata areavailable for occurrencesof this mineralfrom this g.o.ruf"..r. LoNc Gur.cnOccunneNcn The cerium-bearingepidote forms prismatic crystals that occasionally measureup to 15 mm. in length and theseare sporadicalrydistributed in narrowsheets of mineralogicallysimple pegmatite 3-4 inchesin width. rn generalthe allanite crystalsare elongatedparallel to the 6 crystallo- graphicaxis, and in sectionsthat are cut paralrelto a plane coniaining the o and c axes,a roughlyhexagonal outline due to appioximatelyequar developmentof basal planes,orthopinacoids, and hemiorthodomesis evident. MrNBnerocyor.THE pncuarrrp aNt Hosr Rocr 234 C, OSBORNE HUTTON according to the Carlsbad law. Where andesineadjoins orthoclase, nar- row selvedgesshow a myrmekite-like structure with minute vermicular interpenetration of plagioclase by orthoclase or microcline. Orthoclase, whicl makes up about 15 per cent of the total rock, is usually untwinned and here and there a few crystals of microcline with poorly developed cross-hatch twinning were observed. In the pegmatite itself microcline and orthoclase are pink in color and more plentiful than in the granodio- rite; and in addition both potash feldsparsexhibit a regular arrangement of inclusionsof minute blebs of plagioclase(Anzo; a: I.542;7:1'550) of the same composition as the associatedpegmatitic plagioclase,although the latter it wiil be noted, is less calcic than the plagioclase in the en- closing granodiorite. The potash feldspar of the pegmatite zone shows strong replacement structures where it adjoins the plagioclase of the host rock.
    [Show full text]
  • The BACKBENDER's GAZETTE the Newsletter of the Houston Gem & Mineral Society Houston, TX Volume XXXIX - No
    The BACKBENDER'S GAZETTE The Newsletter of the Houston Gem & Mineral Society Houston, TX Volume XXXIX - No. 9 September 2008 President’s Message by Terrell William “Terry” Proctor 2008 HGMS President t may not be the biggest show on Earth, but it will be close. For months HGMS, and especially the IShow Committee members, have been working on putting together a memorable event as we host the re- gional and national organizations at our HGMS Show, September 26–28. There are still places for volunteers to help out. We can always use folks who want to be involved in this great show—lend your help. The September issue of Rock & Gem magazine should be out by the time you get this e-mail. It has an article which I wrote called “Houston Rocks.” It plays up our Show hosting the SCFMS and AFMS, NASA and the fact that they are bringing a moon rock to our Show, the Houston Museum of Natural Science with whom HGMS has had a long affiliation and partner- ship in many activities, the small Proctor Museum of Natural Science, the fact that there are a number of good dig sites a short distance from Houston, and other positive things about Houston. Isn’t it grand being a Houstonian? People all over the Earth complain about their weather, Continued on page 4 General Meeting Programs by Terry Proctor ugust 26, 2008: Patrick J. Lewis, PhD of Sam Houston State University, has just returned from his dig in South Africa. He promises an exciting program Aon the cave in which he dug and his prehistoric finds.
    [Show full text]