 | | Journal (article/letter/editorial) | | 45, 1982, PP. 87 99 The Laytonville Quarry (Mendocino County California) exotic block: iron-rich blueschist-facies...University of Cambridge ABSTRACT. The Laytonville Quarry exotic block con- panying quartzites have become...recalculation, see the Appendix. THE Laytonville Quarry exotic block is the type locality for the minerals... Situated 8 km south of Laytonville (Mendocino County, California), the exotic block, originally 40 m...while the accomFIG. 1. Lithology of the Laytonville Quarry exotic * Present address: 20 Emery Street, Cambridge |  | | Journal (article/letter/editorial) | | Blueschists, Associated Eclogites, and Amphibolites from Oregon and California ABSTRACT Isolated blocks of high-grade...eugeosynclinal deposits of the Coast Ranges of southwestern Oregon and California. The blocks range in size from individual...Formation in California and Otter Point Formation in Oregon. The younger ages for glaucophane probably reflect...blocks of this terrane within melange zones in Oregon and California may be related to later plate interaction...Cretaceous eugeosynclinal deposits of southwestern Oregon and the Coast Ranges of California has puzzled |  | | Journal (article/letter/editorial) | | paper were collected from localities in California, Oregon, Washington State, the Alps, and Greece. Further...within the following authors' works: Laytonvitle Quarry exotic block, Mendocino Co., California--Chesterman...Fork), Santa Clara Co., California and Powers Quarry, Coos Co., Oregon--Muir Wood (I977); Shuksan, Washington...grid has been constructed. Although the mineral omphacite is known to interrupt the intervening jadeite-diopside...Vass ~ 9 Tauern \ ~-V_ % Fe3+ PowerSsifnos Quarry [] 9 Cazadero ".//~'. "<~', "x "". O --% 9 |  | | Journal (article/letter/editorial) | | and its fractionation depends on the garnet and omphacite of the eclogite, not on plagioclase and clinopyroxene...pressure by effective removal of omphacite or shift of the garnet-omphacite boundary 'surface' will give...magma at low pressure. Similarly, increase of the omphacite constituents in the magma at high pressure by...determining the parental magma have been applied by Powers (1955, pp. 95, 100-1), who plotted MgO against...varieties, special attention was first directed by Powers (1932) and Anderson (1941, p. 384), and later by |  | | Report (issue) | | X-ray Powder Pattern: Clear Creek, California, USA. 2.831 (100), 2.922 (75), 4.29 (45), 3.10 (30), 2...99.96 99.87 (1) New Idria district, California, USA; corresponds to (Na0:98 Ca0:01 )§=0:99 (Al0:98 Fe3+...)§=1:00 Si2:00 O6 : (2) Cloverdale, California, USA; corresponds to 2+ (Na0:80 Ca0:05 K0:02 )§=0:87 (Al0:87...Association: zeolites. Albite, quartz, muscovite, omphacite, glaucophane, calcite, aragonite, analcime, Distribution:...Japan. Around Lake Baikal, Siberia, Russia. In the USA, in California, as crystals in boulders along the |  | | Journal (issue) | | Royal Gems – Montana and Yogo Sapphires Benito County, California; the group of sapGems Found in the...Turquoise ite Country, Montana. Photos of gemstones Oregon Sunstone – A Rare and Beautiful American Gemstone...Daniel Bronfen, Brazil Evan Caplan, USA Rocco Gay, Italy Sushil Goyal, USA Shahina Hatta, Hong Kong Dwarka...Thailand Immediate Past President Benjamin Hackman, USA Chief Executive Officer Gary Roskin ICA General Manager...31 W. 47th Street, Suite 1103 New York, NY 10036 USA ica@gemstone.org T: 1.212.620.0900 F: 1.212.352.9054 |  | | Journal (issue) | | halite • Similar-appearing green stones: jadeite, omphacite, and hydrogrossular • Beryllium- and tungsten-bearing...fayalite (Fe), olivine (Mg), rhodonite (Mn), omphacite (Na), ilmenite (Ti), K-feldspar (K), and pure...Red copper-containing plagioclase feldspar from Oregon has been available for over a century. In the early...locality, as well as those from mining districts in Oregon, and pale yellow plagioclase from Mexican localities...The labradorites were reported to be from Modoc County, California. This area still has not been confirmed |  | | Journal (article/letter/editorial) | | this study were prepared using a series of diamond powers of decreasing grain size for surface grinding and...consistent with previous results from TEM analyses of omphacite in eclogites from the Sulu UHP terrane (Shau et...between monoclinic clinopyroxene (McCormick, 1986: omphacite, C2/c, a = 9.50, b = 8.65, c = 5.24, α = 90°,...orientation relationship between barroisite and omphacite has been found in retrogressed eclogites from...of barroisite on omphacite through a 180° rotation around the [001] axis of omphacite (McNamara et al |  | | Journal (article/letter/editorial) | | simulations predict the order–disorder transition in omphacite at 1,150 ± 20C in good agreement with the experimental...stabilization of the ordered intermediate P2/n phase, omphacite (Carpenter 1981). In the P2/n structure M2 and...speculation regarding the ground state structure of omphacite. Rossi et al. (1983) suggested that the ground...prepared from the structure of fully ordered omphacite by substituting appropriate numbers of Ca, Mg...the lowest energies correspond to two natural omphacite samples crystallized presumably below 873 K Long-range |  | | Journal (article/letter/editorial) | | suite. As early as 1935 it was suggested by H. A. Powers that the rocks now recognized as belonging to the...basalt of lower Eocene age in western Washington and Oregon lies very close to the line (P. D. Snavely, Jr...be pointed out that older analyses (Macdonald & Powers, 1946; Macdonald, 1955, table 1) show that as a...aid of Dr. H. A. Powers, cross-check analyses of four samples were made by Dorothy Powers under the supervision...between the analyses by Katsura and those by Mrs. Powers, and the conventional mean values for W-l given |  | Vinograd, V. L., Safonov, O. G., Wilson, D. J., Perchuk, L. L., Bindi, L., Gale, J. D., Winkler, B. (2010) Atomistic model of diopside-K-jadeite (CaMgSi2O6-KAlSi2O6) solid solution. Petrology, 18 (4) 447-459 doi:10.1134/s0869591110040089 | Journal (article/letter/editorial) | | where it has been shown that phase transitions in omphacite (CaNaMgAlSi4O12) and cordierite (Mg3Al4Si5O18)...1356.33 –3.10 A2: CaMgKAlSi4O12 P2/n, normal omphacite Unit cell parameter EXP* a (Å) b (Å) c (Å) α...59 0.5 0.33 A1: CaMgKAlSi4O12 P2/n, inverted omphacite KAlSi2O6 (C2/c) DFT EPM DFT EPM DFT 9.747...diopside (Raudsepp et al., 1990) and for nat ural omphacite (Matsumoto et al., 1975). lowtemperature microcline...K2Al2Ca2Mg2Si8O24) and the space group P2/n of omphacite. The cation arrangement in phase A2 is similar |  | | Journal (article/letter/editorial) | | some basalt comes from depths greater than 60 km. (Powers 1955). Verhoogen (1954) argued from the absence...pressures. Eclogites comprise two principal phases, omphacite and garnet, with accessory biotite, amphibole...suggested that the " eutectic like " behaviour of omphacite and garnet (in terms of which tholeiite and alkali...higher pressures the eutectic shifts towards omphacite and an alkali basalt magma is produced by partial...to shift the eutectic in the direction of both omphacite and amphibole. This is shown on Text-fig. 1 where |  | | Report (issue) | | University Station Stop C1100 Austin, Texas 78712, USA W.D. Carlson Department of Geological Sciences Jackson...University Station C1100 Austin, Texas 78712-0254, USA M.C. Gilbert School of Geology and Geophysics University...University of Oklahoma Norman, Oklahoma 73019, USA J.G. Liou Department of Geological and Environmental...Stanford University Stanford, California 94305-2115, USA S.S. Sorensen Department of Mineral Sciences National...Smithsonian Institution Washington, DC 20560-0119, USA te THE GEOLOGICAL SOCIETY OF AMERICA® Special Paper |  | | Book (volume) | | 01225 442836) Distributors USA AAPG Bookstore PO Box 979 Tulsa OK 74101-0979 USA (Orders: Tel. (918) 584-2555...Minerals, three new minerals from the Laytonville Quarry, California were named by S. O. Agrell after the...anthophyllite and cummingtonite near Chester, Vermont, USA, and which have regularly repeating sequences of...biotite and rutile. Post Pond Volcanics, Vermont, USA (Spear 1980). ‘ 13 Anthophyllite, cordierite-amphibole-bearing...Volcanics, Vermont, USA (Spear 1980). 15 Anthophyllite, metagabbro, Hastings County, Ontario (Tilley 1957) |  | | Report (volume) | | The Colebrooke Schist of Southwestern Oregon and its Relation to the Tectonic Evolution of the Region...PLATE 1. Geologic map of part of southwestern Oregon showing distribution of the Colebrooke Schist___________________...metamorphic rocks of New Zealand, southwestern Oregon, and California________ 12. Triangular plot of...Physical and mineralogic character of southwestern Oregon serpentinites_ __ __ _ _ __ _ _ _ _ _ _ _ _ _ _...46 52 54 THE COLEBROOKE SCHIST OF SOUTHWESTERN OREGON AND ITS RELATION TO THE TECTONIC EVOLUTION OF THE |  | | Journal (article/letter/editorial) | | clinopyroxene is also strongly influenced by XFe3+, with omphacite Figs 2 and 3 (XFe3+ ¼ 0) Figs 2 and 3 (XFe3+...clinopyroxene) in more Fe3+-rich compositions (Fig. 2). Omphacite is calculated to be stable at pressures above...denotes the suprasolvus extension of the diopside– omphacite transition and the solid lines the position of...Diopside does not show the same sensitivity as omphacite to Fe3+ and is stable at pressures above 11 kbar...clinopyroxene solvus allows coexisting diopside and omphacite at XFe3+ between 0.25 and 0.55 at 11– 13.8 kbar |  | Mottana, A., Murata, T., Wu, Z., Marcelli, A., Paris, E. (1996) Order-disorder determination in omphacites via XAS at Ca, Na, Mg, Al K-edges, and its interpretation by the multichannel multiple scattering theory. Physics and Chemistry of Minerals, 23 (4) doi:10.1007/bf00207752 | Journal (article/letter/editorial) | | from Garnet Ridge, Arizona (P 1-25), and ordered omphacite from Biella, Italy (M.1). The number of atoms... to detect because of their similar scattering powers. MMS calculations are the tool to quantify such |  | | Report (chapter) | | 1985, Ellis & Green 1985, Perkins & Chipera 1985, Powers & Bohlen 1985, Avchenko 1986, Waters 1986, Bhattacharya...determined the lower pressure limit of ordered omphacite in an assemblage with quartz and high albite,...exchange of disordered omphacite with garnet are inappropriate for ordered omphacite (Essene 1982, Koons...with Mg/Fe exchange reactions involving ordered omphacite. Barometry of crustal (type B and C) eclogites...of Science, 278,769-97. CARPENTER, M. A. 1981. Omphacite microstructures as time-temperature indicators |  | | Journal (article/letter/editorial) | | Average Coesite ( + 8.6%O), thin section Average Omphacite (+7.8%O), thick section Average Garnet (+6.7%)...with a tightly focussed beam of 100/zm. Higher powers tend to make holes that are too large and lower...gives the results of a thick section in a single omphacite crystal. Significant isotopic variations were...crystal surface. The laser bored through the omphacite and into the quartz in these areas. The apparently...SHARP Fig. 5. Photograph and sketch of a single omphacite crystal in quartzite. The d~SO-values for each |  | | Journal (article/letter/editorial) | | 1967; Fig. 1) and incorporates the change to more omphacite-rich clinopyroxene compositions through the breakdown...assemblages may ultimately produce eclogite (omphacite + garnet) by a sequence of corona-producing reactions...range of clinopyroxenes, from sodic augite to omphacite, and cannot be distinguished on the basis of the...terranes have been advocated for the Adirondacks (Powers & Bohlen, 1985; Bohlen, 1987) and applied to a...craton. European Journal of Mineralogy, in press. Powers, R. E. & Bohlen, S. R., 1985. The role of syn-metamorphic |  | | Report (issue) | | of the Jump Creek Rhyolite, Pole Creek canyon, Oregon. (Bottom right) The north cataract of the 55-meter-high...the North American Craton Beneath Southeastern Oregon: A Multidisciplinary Approach By James G. Evans...As an Extensional Strike-slip Duplex, Idaho and Oregon By Peter Hooper, Jenda Johnson, and Chris Hawkesworth...History of the Western Snake River Plain, Idaho and Oregon By Spencer H. Wood and Drew M. Clemens 69 Detrital...195 The Juniper Mountain Volcanic Center, Owyhee County, Southwestern Idaho: Age Relations and Physical |  | | Journal (article/letter/editorial) | | (Depths of the Earth Company, Cave Creek, Arizona, USA) at Kingston University. All the experiments were...in SH3 is small- to medium-sized crystals of omphacite (Jd28). There are also a few larger, zoned pyroxene...augite (Jd11) and the rims are more magnesian omphacite (Jd35). All these pyroxenes were formed during...undergoing high-grade regional metamorphism (e.g., Powers and Bohlen, 1985; Finger and Clemens, 1995). The...with Pl-free (eclogitic) assemblages of Grt + omphacite (Omp). Various aspects and the P-T location of |  | | Journal (article/letter/editorial) | | Seven Grts Phg and (WR, Omp or Grt) Phengite Omphacite 40 Ar/39Ar laser fusing Grt, Omp intersection... (1999) WR, Whole rock; Phg, Phengite; Omp, Omphacite; Grt, Garnet. of the thermal evolution of UHP...The light-coloured eclogites contain garnet, omphacite, quartz, kyanite and phengite, along with minor...pseudomorphs occur as inclusions in garnet and omphacite (Zhang et al., 1995). The minerals show little...and texture of eclogite DB-1. Grt, Garnet; Omp, Omphacite; Kyn, Kyanite; Rtl, Rutile; Qz, Quartz. normal |  | | Journal (article/letter/editorial) | | SiO2 than jadeite. If some eclogite contains omphacite close in composition to jadeite, it is possible...above discussion that the melting of garnet and omphacite would produce liquids of group B under higher...of garnet rich in pyrope, aluminian bronzite, omphacite, spinel, and variable amounts of olivine. Garnet...Fiske of the Johns Hopkins University, Drs. H. A. Powers and R. Wilcox of the U.S. Geological Survey, and |  | Wang, Liping, Rouse, Roland C., Essene, Eric J., Peacor, Donald R., Zhang, Youxue (2000) Carmichaelite, a new hydroxyl-bearing titanate from Garnet Ridge, Arizona. American Mineralogist, 85 (5) 792-800 doi:10.2138/am-2000-5-620 | Journal (article/letter/editorial) | | distances and the approximate X-ray scattering powers at the cation sites deduced from the “all titanium...similarity in cation radii and X-ray scattering powers of Ti, V, Cr, and Fe; (2) the existence of multiple...with chromite, rutile, magnesite, chloritoid, omphacite, talc and garnet. The chemical composition of...related rocks in the Moses Rock dike, San Juan County, Utah. American Mineralogist, 55, 1738–1771. McGetchin...inclusions in pyrope crystals from Garnet Ridge, Arizona, USA: Implications for processes in the upper mantle. |
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