ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Series available for loan
    Series available for loan
    Blueschists and eclogites (1986)
    Boulder, Colo. : The Geological Society of America
    Associated volumes
    Details Availability
    Call number: S 90.0006(164)
    In: Memoir / The Geological Society of America, 164
    Type of Medium: Series available for loan
    Pages: VII, 423 Seiten , Illustrationen, graphische Darstellung, Karten
    ISBN: 0-8137-1164-9
    Series Statement: Memoir / The Geological Society of America 164
    URL: http://digitale-objekte.hbz-nrw.de/storage/2009/02/12/file_26/2810789.pdf
    Language: English
    Note: Foreword Experimental investigations of blueschist-greenschist transition equilibria: Pressure dependence ofAl₂O₃ contents in sodic amphiboles - A new geobarometer (Shigenori Maruyama, Moonsup Cho, and J. G. Liou) Metamorphic temperatures and pressures of Group B and C eclogites (Robert C. Newton) Phase relationships of ellenbergerite, a new high-pressure Mg-Al-Ti silicate in pyrope-coesite-quartzite from the Western Alps (Christian Chopin) Petrology and tectonic implications of the blueschist-bearing Puerto Nuevo melange complex, Vizcaino Peninsula, Baja California Sur, Mexico (Thomas E. Moore) Petrologic and geochemical comparison of the blueschist and greenschist units of the Catalina Schist terrane, southern California (Sorena Svea Sorensen) Blueschists in the Franciscan Complex of California: Petrotectonic constraints on uplift mechanisms (Mark CIoos) Geochronology of high-pressure-low-temperature Franciscan metabasites: A new approach using the U-Pb system (James M. Mattinson) Blueschist metamorphism of the Eastern Franciscan belt, northern California (A. S. Jayko, M. C. Blake, Jr., and R. N. Brothers) Deformation and high PIT metamorphism in the central part of the Condrey Mountain window, north-central Klamath Mountains, California and Oregon (Mark A. Helper) Geology of the Shuksan Suite, North Cascades, Washington, U.S.A (Edwin H. Brown) Phase petrology of eclogitic rocks in the Fairbanks district, Alaska (Edwin H. Brown and Robert B. Forbes) Field relations and metamorphism of the Raspberry Schist, Kodiak Islands, Alaska (Sarah M. Roeske) Rb-Sr and K-Ar study of metamorphic rocks of the Seward Peninsula and Southern Brooks Range, Alaska (Richard L. Armstrong, Joseph E. Harakal, Robert B. Forbes) Bernard W. Evans, and Stephen Pollock Thurston Caledonian high-pressure metamorphism in central western Spitsbergen (Yoshihide Ohta, Takao Hirajima, and Yoshikuni Hiroi) A greenschist protolithfor blueschist in Anglesey, U.K. (Wes Gibbons and Mark Gyopari) Rb-Sr and U-Pb dating of the blueschists of the Ile de Groix (France) (Jean-Jacques Peucat) Blue amphiboles in metamorphosed Mesozoic mafic rocks from the Central Alps (R. Oberhänsli) Early Alpine eclogite metamorphism in the Penninic Monte Rosa-Gran Paradiso basement nappes of the northwestern Alps (Giorgio V. Dal Piaz and Bruno Lombardo) Blueschist-facies metamorphism of manganiferous cherts: A review of the alpine occurrences (Annibale Mottana) The blueschist fades schistes lustrés of Alpine Corsica: A review (Wes Gibbons, Colin Waters, and John Warburton) The ophiolite-bearing Schistes lustrés nappe in Alpine Corsica: A model for the emplacement ofophiolites that have suffered HP/LT metamorphism (John Warburton) High-pressure/low-temperature metamorphic rocks of Turkey (A. I. Okay) Eclogues from various types of metamorphic complexes in the USSR and the problems of their origin (N. V. Sobolev, N. L. Dobretsov, A. B. Bakirov, and V. S. Shatsky) The high-pressure metamorphic belts of Japan: A review (Shohei Banno) The origin and metamorphic history of the ultramafic and metagabbro bodies in the Sanbagawa metamorphic belt (K. Kunugiza, A. Takasu, and S. Banno) Strain patterns in the Sanbagawa and Ryoke paired metamorphic belts, Japan (Mitsuhiro Toriumi and Megumi Masui) A low PIT metamorphic episode in the Biei area, Kamuikotan blueschist terrane, Japan (Hirokazu Maekawa) Regional eclogite fades in the high-pressure metamorphic belt of New Caledonia (K. Yokoyama, R. N. Brothers, and P. M. Black)
    Location: Lower compact magazine
    Branch Library: GFZ Library
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    BOOK
    Link to Library Catalog
    get availability status
  • 2
    Electronic Resource
    Electronic Resource
    Limited fluid-rock interaction at marble-gneiss contacts during Cretaceous granulite-facies metamorphism, Seward Peninsula, Alaska (1993)
    Springer
    Contributions to mineralogy and petrology 114 (1993), S. 27-41 
    Details
    ISSN: 1432-0967
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract Stable-isotope profiles show that flat-lying marble units acted as impermeable barriers to upward fluid flow in transitional amphibolite-granulite grade rocks of the Kigluaik Mountains, Seward Peninsula, Alaska. The degree of permeability is related to the composition of the marble. The margin of a thick pure dolomite marble chemically reacted with underlying metasyenite (aH2O=0.2) to form a 2 cm boundary layer of calcite + forsterite by introduction of SiO2. No fluid penetrated past this reaction front, although the high temperature of metamorphism (∼800°C) allowed transport of carbon and oxygen isotopes for an additional 2 cm by diffusion through the solid dolomite. A second marble with a higher silica content underwent more decarbonation, which enhanced porosity and lead to a greater extent of isotope transport (2–3 m) in contact with quartzo-feld-spathic gneiss below. An estimate of total fluid flux across the bottom of this marble layer based on the shape of the isotope profile is 1 cm3/cm2 directed down, out of the marble. At two other marble-gneiss contacts steep isotopic gradients coincide with lithologic contacts, indicating very little cross-lithology fluid flow. The extent of diffusional transport of isotopes in the marbles is limited and interpreted as indicating the transient presence of a pore fluid, generated by thermally driven devolatilization reactions. No wholesale pervasive advection of C-O-H fluid occurred across the thick, continuous, marble units near the exposed base of the Kigluaik Group section during the entire regional metamorphic cycle. Activities of pore-fluid species were controlled by internal processes. Movement of volatiles and stable-isotopes between contrasting rock-types was dominantly diffusive. Channelized fluid pathways through the marble units developed during uplift and cooling but were not present during peak metamorphism. Heating of the section occurred by conduction, probably from an underlying magma source, and not by advection of a C-O-H fluid.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00307863
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    The role of olivine in the crystallization of the prehistoric Makaopuhi tholeiitic lava lake, Hawaii (1967)
    Springer
    Contributions to mineralogy and petrology 15 (1967), S. 202-223 
    Details
    ISSN: 1432-0967
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract On eruption, the tholeiitic basalt lava of the prehistoric Makaopuhi lake contained nearly seven percent euhedral olivine phenocrysts of approximately Fa14 composition. In the center of the 225 foot vertical section of the lake, the lava became more than 90 percent solid at 1000° C after about 30 years. At the surface the lava was quenched to air temperature, whereas, at the bottom, quenching to 800° C was followed by a 40 year period before the temperature reached 700° C. The olivine phenocrysts settled at an average rate of about 4 × 10−6 cm Sec−1 to form a zone that contains 21 percent olivine 75 feet above the base. Sinking of olivines continued until some time after the beginning of the crystallization of augite and plagioclase. Thin rims of iron-rich olivine (up to Fa55) surrounding the phenocrysts, and a second generation of fine-grained olivines (Fa20 Fa48) restricted to the uppermost 20 feet indicate local extensions of the period of crystallization of olivine. During crystallization of the groundmass and later subsolidus cooling in the range 1000° C to at least as low as 800° C, the olivine phenocrysts were converted to Fa30–40 by interdiffusion of Fe, Mg, Ni, and Mn. Homogenization of Mg-rich cores and Fe-rich margins and equilibration of olivine composition with the groundmass phases was progressively less well achieved toward the top of the lake. Reaction rims around the olivines are composed primarily of Ca-rich pyroxene. Pigeonite crystallized alongside augite except in the uppermost 5 feet where there is abundant ground mass olivine. Poikilitic hypersthene grew at the expense of pre-existing ferromagnesian minerals in the cumulate zone.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01185342
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Mineralogy as a function of depth in the prehistoric Makaopuhi tholeiitic lava lake, Hawaii (1968)
    Springer
    Contributions to mineralogy and petrology 17 (1968), S. 85-115 
    Details
    ISSN: 1432-0967
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract The electron probe X-ray microanalyzer has been used to determine the compositional variability of the groundmass minerals and glass in 10 specimens from a complete 225-foot section of the prehistoric tholeiitic lava lake of Makaopuhi Crater, Hawaii. The order of beginning of crystallization was: (1) chromite, (2) olivine, (3) augite, (4) plagioclase, (5) pigeonite, (6) iron-titanium oxides and orthopyroxene, (7) alkali feldspar and apatite, and (8) glass. Although the lake is chemically tholeiitic throughout, the occurrence of ferromagnesian minerals is as though there were a gradation from alkali olivine basalt in the upper chill downwards to olivine tholeiite. Groundmass olivine decreases downwards and disappears at about 20 feet. Pigeonite is absent in the uppermost 5±2 feet, then increases in amount down to 20 feet, below which augite and pigeonite coexist in constant 2∶1 proportions. Strong zoning and metastable compositions characterize the pyroxenes of the chilled zones, but these features gradually disappear towards the interior of the lake to give way to equilibrium pyroxenes. Relatively homogeneous poikilitic orthopyroxene (≈ Ca4Mg70Fe26) occurs in the olivine cumulate zone, having formed partly at the expense of pre-existing olivine, augite, and pigeonite (≈ Ca8Mg66Fe26). The growth of orthopyroxene is believed to have been facilitated by the slower cooling rate and higher volatile pressure at depth, and by the rise in Mg/Fe ratio of the liquid due to the partial dissolution of settled olivine. Unlike olivine and pyroxene, feldspar is least zoned in the upper and lower chilled regions. The greatest range of compositional zoning in feldspar occurs at 160 to 190 feet, where it extends continuously from Or1.0Ab22An77 to Or64Ab33An3. The feldspar fractionation trend in the An-Ab-Or triangle gradually shifts with depth toward more “equilibrium” trends, even though the zoning becomes more extreme. The variation with depth in the initial (core) composition of the plagioclase suggests the influence of either slow nucleation and growth (undercooling) or slow diffusion in the liquid, relative to the rate of cooling. Idiomorphic opaque inclusions in olivine phenocrysts are chrome-spinels showing continuous variation from 60 percent chromite to 85 percent ulvospinel and to magnetite-rich spinel. A pre-eruption trend of increasing Al with decreasing Cr can be recognized in chromites from the upper chill. Most of the inclusions show a trend of falling Cr and Al, toward an ulvospinelmagnetite solid solution which is progressively poorer in Usp with depth. This trend was produced by solid state alteration of the chromite inclusions during cooling in the lava lake. Ilmenite (average Ilm91Hm9) coexists with variably oxidized titaniferous magnetite in the basalt groundmass. Estimated oxygen fugacities agree well with other independent determinations in tholeiitic basalt. No sulfide phase has been detected. Fractional crystallization produced a groundmass glass of granitic composition. Average, in percent, is: SiO2, 75.5; Al2O3, 12.5; K2O, 5.7; Na2O, 3.1; CaO, 0.3; MgO, 0.05; total FeO, 1.2; and TiO2, 0.8. Normative Or〉 Ab. Minor changes in glass composition with depth are consistent with a greater approach towards the granite minimum. Incipient devitrification precluded reliable analysis of glass from the lower half of the section. The SiO2-phase associated with devitrification contains alkalis and Al and is believed to be cristobalite. Needle-like apatite crystals in the groundmass glass are Siand Fe-bearing fluorapatites containing appreciable rare earths (predominantly Ce) and variable Cl. The grain-size and maximum An content of the cores of plagioclase grains were controlled by cooling rate and are at a maximum at the center of the section. The most homogeneous pyroxene (and olivine, Moore and Evans, 1967), most equilibrium pyroxene trends, most abundant alkali feldspar, and most equilibrium feldspar trends are found at 160 to 190 feet, which is appreciably below that part of the lake which was slowest to crystallize. Volatile pressure, increasing with depth, possibly controlled the degree of attainment of equilibrium more than cooling rate. Since they are dependent on cooling history, some of the modal criteria commonly used for recognizing basalt types, such as the absence of Ca-poor pyroxene, presence of groundmass olivine, and the presence of alkali feldspar, should be applied with caution. Petrographic comparison of basalts from one flow, volcano, or province, with another, should recognize the possible variations due to cooling history alone.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00373204
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Scapolite stoichiometry (1969)
    Springer
    Contributions to mineralogy and petrology 24 (1969), S. 293-305 
    Details
    ISSN: 1432-0967
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract Over the range Ca/(Ca + Na) from zero to 0.75, scapolites vary linearly between Na4Al3Si9O24Cl and NaCa3Al5Si7O24CO3, by means of a coupled replacement of Na3Si2Cl by Ca3Al2CO3. Ca includes minor Sr, Na includes K, and CO3 may include substantial SO4. From Ca/(Ca + Na) = 0.75 to 1.00, variation is between NaCa3Al5Si7O24CO3 and Ca4Al6Si6O24CO3, by means of a coupled replacement of NaSi by CaAl, as in plagioclase. Anion substitution is complete at the 0.75 point. Recalculation of scapolite analyses on the basis of Al + Si atoms = 12.0, as suggested by computed unit cell contents, offers a reasonable basis for normalization of atomic proportions. On this basis, Ca + Sr + Na + K + Fe atoms total very close to 4.0. New limits on the minor element content of scapolite are proposed. In view of the inflection at 0.75, subdivision of the scapolites at Ca/(Ca + Na) ratios of 0.25, 0.5, and 0.75 seems more logical than the 0.2, 0.5, and 0.8 limits used hitherto for marialite, dipyre, mizzonite, and meionite.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00371272
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Garnet-bearing ultramafic rocks from the Erzgebirge, and their relation to other settings in the Bohemian Massif (1997)
    Springer
    Contributions to mineralogy and petrology 127 (1997), S. 57-74 
    Details
    ISSN: 1432-0967
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract Garnet-bearing ultramafic rocks (GBU) enclosed in high-grade gneisses are known from several parts of the Bohemian Massif. One of these is the high-pressure(HP)-unit 1 in the Erzgebirge Crystalline Complex, which is the subject of the present study. Hitherto, two different models have been put forward to explain the stabilisation of garnet in mantle-derived ultramafic rocks from the Bohemian Massif and their emplacement into the crust. (1) Garnetiferous assemblages were formed in the ultramafics before they came in contact with their crustal host rocks. (2) Garnet was formed in the ultramafics at the expense of spinel due to cooling caused by their tectonic emplacement in the crust. The PT-evolution revealed by the investigated GBU from the Erzgebirge Crystalline Complex, however, requires a third model. The reconstruction of the PT-paths for the Erzgebirge GBU is based on both conventional thermobarometry and phase relations. Thermodynamic calculations allowed the construction of a PT-phase diagram for the system Na2O-CaO-MgO-Al2O3-SiO2-H2O, which is the first quantitative petrogenetic grid in this model system relevant to ultramafic HP-rocks. The grid shows the uni-, di-, and tri-variant assemblages stable in peridotitic rocks at different PT-conditions, providing a tool to constrain PT-paths from the succession of mineral assemblages observed in a rock. The PT-path obtained for the Erzgebirge GBU suggests that the garnet-bearing assemblages formed by HP-metamorphism of spinel peridotite which was emplaced into the crust prior to or during the HP-compressional stage. This model is supported by peak PT-conditions around 900 °C and 30–35 kbar recorded by the ultramafic rocks, which are very similar to those attained in the eclogites sensu stricto which occur in the same tectonic unit (HP-unit 1) and for which an in situ metamorphism has been inferred (Schmädicke et al. 1992). On the other hand, the other two high-pressure units in the Erzgebirge, HP-units 2 and 3, which also contain eclogites sensu stricto but lack peridotites, record lower peak PT-conditions of 650–750 °C/24–26 kbar and 600–650 °C/20–24 kbar, respectively. Postulating an in situ HP-metamorphism for the garnet peridotites as result of continental collision during the Variscan orogeny, a crustal thickness of 90–110 km would be required. A comparison of the distribution of eclogites sensu stricto and mantle-derived rocks from the Bohemian Massif together with their reported PT-conditions reveals a correlation between peak PT-conditions in eclogites sensu stricto and the prevailing assemblages in the ultramafic rocks in the same unit. Furthermore, the Erzgebirge Crystalline Complex and the Snieznik Complex on one hand as well␣as the Granulitgebirge and the Sowie Góry on the other hand are thought to be genetically linked. The garnet peridotites from the Granulitgebirge, the Sowie Góry and the Gföhl unit seem to have experienced peak PT-conditions not recorded by their country rocks with non-eclogitic basic interlayers, inferring a formation of␣HP-assemblages in the ultramafics prior to their emplacement into the crust.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004100050265
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Antigorite-ophicarbonates: Contact metamorphism in Valmalenco, Italy (1977)
    Springer
    Contributions to mineralogy and petrology 62 (1977), S. 301-312 
    Details
    ISSN: 1432-0967
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract Outside the Bergell tonalite contact aureole, ophicarbonate rocks consist of blocks of antigorite schist embedded in veins of calcite ± tremolite. An antigorite schistosity predates some of these calcite veins. Mono- and bimineralic assemblages occur in reaction zones associated with the veins. Within the aureole, the ophicarbonate veining becomes less distinct and polymineralic assemblages become more frequent. A regular sequence of isobaric univariant assemblages is found, separated by isograds corresponding to isobaric invariant assemblages. In order of increasing grade the invariant assemblages are: antigorite+diopside+olivine+tremolite+calcite antigorite+dolomite+olivine+tremolite+calcite antigorite+olivine+talc+magnesite antigorite+dolomite+olivine+tremolite+talc These assemblages match a previously derived topology in P-T-XCO2 space for the system CaO-MgO-SiO2-H2O-CO2; the field sequence can be used to adjust the relative locations of calculated invariant points with respect to temperature. Isobaric univariant and invariant assemblages are plotted along a profile map to permit direct comparison with the phase diagram. It is inferred that, during the formation of the ophicarbonate veins, calcite precipitated from fluid introduced into the serpentinite. During contact metamorphism, however, the compositions of pore fluids evolved by reaction in the ophicarbonate rocks were largely buffered by the solid phases. This control occurred on a small scale, because there are local variations in the buffering solid assemblages within a centimeter range.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00371017
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Widespread occurrence of magnesiocummingtonite in ultramafic schists, Cima di Gagnone, Ticino, Switzerland (1974)
    Springer
    Contributions to mineralogy and petrology 43 (1974), S. 245-251 
    Details
    ISSN: 1432-0967
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract Abundant magnesiocummingtonite (space group P21/m) with Mg/(Mg+Fe) ratios between 0.85 and 0.89 occurs in lenses of schistose metaperidotite enclosed in kyanite-zone rocks of the Lepontine Alps, Ticino, Switzerland. It forms prisms and needles that extend homoaxially from cores of tremolite. Coexisting magnesian phases are olivine, orthopyroxene, talc, magnesite, and chlorite. Except for γ∶z, optical and structural properties of one example fall on extrapolations of existing determinative curves. Analogous to synthetic F-clinoamphiboles, zz∶z has a maximum at approximately 0.7 Mg/(Mg+Fe). Anthophyllite, of almost identical composition, occurs in the same region, often intergrown with cummingtonite along lamellae ‖(010) and ‖(100). Cummingtonite is believed to have partially inverted to anthophyllite during cooling.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00373481
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Antigorite-ophicarbonates: Phase relations in a portion of the system CaO-MgO-SiO2-H2O-CO2 (1977)
    Springer
    Contributions to mineralogy and petrology 60 (1977), S. 39-56 
    Details
    ISSN: 1432-0967
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract The occurrence of critical assemblages among antigorite, diopside, tremolite, forsterite, talc, calcite, dolomite and magnesite in progressively metamorphosed ophicarbonate rocks, together with experimental data, permits the construction of phase diagrams in terms of the variables P, T, and composition of a binary CO2-H2O fluid. Equilibrium constants are given for the 30 equilibria that describe all relations among the above phases. Ophicalcite, ophidolomite, and ophimagnesite assemblages occupy partially overlapping fields in the $$T - X_{{\text{CO}}_{\text{2}} } $$ diagram. The upper temperature limit of ophicalcite rocks lies below that of ophidolomite and ophimagnesite. The fluid phase in ophicarbonate rocks has $$X_{{\text{H}}_{\text{2}} {\text{O}}} 〉 0.8$$ , and there are indications that $$P_{{\text{H}}_{\text{2}} {\text{O}}} + P_{{\text{CO}}_{\text{2}} } $$ during their progressive metamorphism is approximately equal to P total.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00372850
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Titanian hydroxyl-clinohumite: Formation and breakdown in antigorite rocks (Malenco, Italy) (1980)
    Springer
    Contributions to mineralogy and petrology 72 (1980), S. 229-242 
    Details
    ISSN: 1432-0967
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract Petrographic evidence is presented for the breakdown of titanian hydroxyl-clinohumite to olivine+magnesian ilmenite (or geikielite)±magnetite in the outermost zone of the Bergell aureole in the Malenco Serpentinite, Prov. Sondrio, Italy. The breakdown coincides in the field with the isograd reaction: antigorite+diopside=olivine+tremolite+H2O. It is therefore concluded that this variety of clinohumite is unstable above approximately 520° C at a pressure of 3 kbars. Elsewhere in the Malenco Serpentinite, titanian hydroxyl-clinohumite may be found to have reacted with CO2 to produce antigorite, magnesian ilmenite and magnesite. Titanian hydroxyl-chondrodite was detected in one sample. Under crustal pressures, the stability field of F-free clinohumite is entirely contained inside that of antigorite. The stable occurrence of titanian clinohumite in high-grade metamorphic ultrabasic rocks may be attributed to the substitution of F for OH.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00376142
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...