 | | Journal (article/letter/editorial) | | common. Orthopyroxene,Ca pyroxene, fayalite,cummingtonite, andhornblende are the mostabundant silicates...Iron Formation), and a thick upper clasticunit (Virginia Formation). Both the Early and Middle Precambrianrocks...Dunka River area. overlain conformablyby the Virginia Formation ern Minnesotageologicunits suggestthat...iron-formation depositionand its metaBiwabik and Virginia Formations as shown in the morphismby the Duluth...erosional Vir#inia Formation The lower part of the Virginia Formation is preinterval of severalhundredmillion |  | BenkĆ³, Zsolt, Mogessie, Aberra, MolnĆ”r, Ferenc, Krenn, Kurt, Poulson, Simon R., Hauck, Steven, Severson, Mark, Arehart, Greg B. (2015) Hydrothermal alteration and CuāNiāPGE mobilization in the charnockitic rocks of the footwall of the South Kawishiwi intrusion, Duluth Complex, USA. Ore Geology Reviews, 67. 170-188 doi:10.1016/j.oregeorev.2014.11.010 | Journal (article/letter/editorial) | | of the South Kawishiwi intrusion, Duluth Complex, USA Zsolt BenkĆ³ a,ā, Aberra Mogessie a, Ferenc MolnĆ”r...University of Nevada ā Reno, 1664 N. Virginia St., Reno, NV 89557-0138, USA d Natural Resources Research Institute...5013 Miller Trunk Highway, Duluth, MN 55811-1442, USA b a r t i c l e i n f o Article history: Received...is overprinted by an actinolite + chlorite + cummingtonite + prehnite + pumpellyite + quartz + calcite...charnockite can be characterized by an actinolite + cummingtonite + chlorite + prehnite + pumpellyite + calcite |  | | Journal (article/letter/editorial) | | group C2/m (structure type tremolite) or P21/m (cummingtonite). Another group comprises the orthorhombic amphiboles...The compressibility of two polymorphs on the cummingtonite-grunerite join up to 8 GPa, and the effect of...pressure on the C2/m-P21/m phase transition of cummingtonite have been reported (Yang et al. 1998; Boffa...along [100], b and c, respectively, for C2/m cummingtonite (Yang et al. 1998) and with the respective values...Protoamphibole Protoamphibole Cummingtonite Cummingtonite Cummingtonite Cummingtonite Grunerite Grunerite Gr |  | Iezzi, G., Della Ventura, G., Tribaudino, M., Nemeth, P., Margiolaki, I., Cavallo, A., Gaillard, F., Behrens, H. (2010) Phase transition induced by solid solution: The BCa-BMg substitution in richteritic amphiboles. American Mineralogist, 95 (2) 369-381 doi:10.2138/am.2010.3308 | Journal (article/letter/editorial) | | For amphiboles, only studies concerning the cummingtonite system are available, and thus restricted to...variation is likely to occur along the (P21/m) cummingtonite-(C2/m) tremolite join where B Ca substitutes...amphiboles . This band is centered at 3668 cmā1 in cummingtonite, and at 3674 cmā1 in tremolite (Gottschalk et...te (Schofield and Redfern 1992, 1993), and cummingtonite-grunerite (Hirschmann et al. 1994; Boffa-Ballaran...listed in Table 6 are natural and close to cummingtonite; these latter have empty A sites and divalent |  | | Journal (article/letter/editorial) | | rock types. Orthorhombic amphibole replaces cummingtonite at high temperature and pressure. The extensive...involving orthorhombic amphiboles, tremolite, cummingtonite, and āhornblendeā (Robinson et al. 1982; Schumacher...of proto-amphibole (Zanazzi et al. 2010) and cummingtonite (Boffa Ballaran et al. 2000). The ambient structures...mainly to anthophyllite, proto-amphibole, and cummingtonite, as these amphiboles are part of the well-defined...Fe2+, Mn2+) in orthorhombic amphiboles and cummingtonite, or [8] for larger cations (Na, K, Ca, Sr) in |  | Comodi, P., Ballaran, T. B., Zanazzi, P. F., Capalbo, C., Zanetti, A., Nazzareni, S. (2010) The effect of oxo-component on the high-pressure behavior of amphiboles. American Mineralogist, 95 (7) 1042-1051 doi:10.2138/am.2010.3429 | Journal (article/letter/editorial) | | The compressibility of two polymorphs on the cummingtonite-grunerite join up to 8 GPa, and the effect of...pressure on the C2/m-P21/m phase transition of cummingtonite have been reported (Yang et al. 1998; Boffa...Kaersutite is much less compressible than tremolite, cummingtonite, and grunerite, and slightly less compressible...amphiboles with the A site empty (tremolite, cummingtonite, and grunerite) are much more compressible than...89(3) Cummingtonite P21/m 62.4(5) Cummingtonite C2/m 66(2) Cummingtonite P21/m 71(1) Cummingtonite C2/m |  | | Journal (issue) | | COMMONWEAL TH OF VIRGINIA DEPARTMENT OF MINES, MINERALS AND ENERGY Richmond, Virginia Published quarterly...GRENVILLE-AGE ULTRAMAFIC PLUTONS IN THE NORTHERN VIRGINIA BLUE RIDGE Stephen W. Kline, Arkansas Mining &...the Grenvillegranitoid basement terrane of the Virginia Blue Ridge, age granitoid basement terrane in...northern Middleburg quadrangle, Virginia. Primary magmatic textures Virginia~ The first documentation of...entirely ofmetapyroxenite. It i NOS. 3 &4 ,. ā¢ VIRGINIA MINERALS the Grenville orogeny. Recent work using |  | | Report (issue) | | x 3. 4. GEOLOGY OF THE BIWABIK FORMATION Virginia Formation . 68 Diabase Dikes and Sills 69 ...amphibole matrix 40 15. Fayalite remnants in cummingtonite-rich matrix. 41 16. Relic magnetite-quartz...magnetite-quartz granules partly replaced by cummingtonite .............. . 43 17. Relic granule structures 44 18...18. Incipient development of cummingtonite 48 xu GEOLOGY OF THE BIWABIK FORMATION 19. Riebeckite...gl1aIluie structures in calcite 79 30. Hornblende+cummingtonite 88 31. Minnesotaite 97 32. Fayalite and |  | | Journal (article/letter/editorial) | | Metamorphic Suite of northwestern North Carolina, USA Loren A. Raymond, Arthur Merschat & R. Kelly Vance...Metamorphic Suite of northwestern North Carolina, USA, International Geology Review, 58:7, 874-912, DOI:...Metamorphic Suite of northwestern North Carolina, USA Loren A. Raymonda, Arthur Merschatb and R. Kelly...State University, Boone, NC, USA; bUS Geological Survey, Reston, VA, USA; cDepartment of Geology and Geography...Geography, Georgia Southern University, Statesboro, GA, USA ABSTRACT ARTICLE HISTORY Metaultramafic rocks |  | | Journal (article/letter/editorial) | | Distribution of Mg and Fe in Cummingtonite-Hornblende and Cummingtonite-ActinolitePairs from Metamorphic...[Mg/Fe]cu m ] are calculated for 31 metamorphic cummingtonite-hornblende pairs. Data on 21 pairs are taken...proportions of the cummingtonite "molecule". The Mg-Fe distributions in the cummingtonite-hornblende pairs...cummingtonites (KD.Mg_Fe Ca-am-Cum ~ 1.5--2.0), the cummingtonite-hornblende pairs diverge towards lower values...distribution coefficient. In most of the metamorphic cummingtonite-hornblendepairs - - including the nine pairs |  | | Journal (article/letter/editorial) | | of xonotlite at Leesburg, Virginia: Am. Mineratr., r0.12-13. CUMMINGTONITE FROM THE MIKONUI RIVER, WESTLAND...Museum of Natural History, New York, N. Y. Cummingtonite has not been recorded from New Zealand, although...shown the presenceof abundant cummingtonite in some of these. The cummingtonite-bearing boulders were collected...mer, they split comparatively easily along cummingtonite-rich surfaces. Other minerals visible to the...rock can best be described as a qaartz-rich cummingtonite-garnet schist. rn some specimens the schistose |  | | Report (issue) | | ........... 45 45 45 46 Metamorphism of the Virginia Formation . . . . . . . . . . . . . . . . . ..... . . . . . . . . . . .. 52 Composition of Cummingtonite-Grunerite Amphiboles ........... 64 CONTENTS...ratio Fe/ (Fe 31. Graph of compositions of cummingtonite-grunerite amphiboles in the metamorphosed Biwabik...Refractive Indices and Estimated Compositions of Cummingtonite-Grunerite Amphiboles from the Metamorphosed...CaCO a near the gabbro. Compositions of the cummingtonite-grunerite amphiboles, determined by refractive |  | | Journal (article/letter/editorial) | | Geological Sciences,Virginia Polytechnic Institute and State University, Blacksburg,Virginia 24061, U.S.A....subgrains(boxedarea)containing narrow " 100" and "T0 1" cummingtonite lamellae (arrows). The porphyroclastsand subglains...automated, four spectrometer electron microprobe at Virginia Polytechnic InExpnnrrvrnNTAl TECHNIeUES stitute...identical to the commonly reported occurrences of cummingtonite exsolution lamellae in calcic amphiboles (e...theselamellaeindicate that they are indeed C2/m cummingtonite. When examined in the TEM, an exsolution microstructure |  | | Journal (article/letter/editorial) | | unoxidized portions later exsolved ulvospinel. Cummingtonite exsolved actinolite, forming irregular patches...plagioclase, augite, inverted pigeonite, olivine, cummingtonite, quartz, and titaniferous magnetite. To a good...se (An94Ab6) + vapor+augite (Wo^oEn^s^) or cummingtonite Fe/(Fe+Mg) Ā£ 0-69; quartz was present but probably...in turn by the predominantly pelitic Rove and Virginia Formations. The Animikie Group, as a whole, unconformably...(XQNORTH SHORE VOLCANIC GROUP M I D D L E PRECAMBRIAN VIRGINIA AND ROVE FORMATIONS AND GUNFLINT IRON FORMATIONS |  | | Journal (article/letter/editorial) | | Keywords: Amphibole, crystal growth, crystal mush, cummingtonite, geothermometry, geobarometry introduCtion...to magnesiohornblende or cummingtonite at the rims. Individual cummingtonite crystals (<250 Āµm) also occur...rhyolite to basaltic-andesite (Fig. 4c), Rhyolite Cummingtonite indicating that pressure also influenced this...tenuous as these are from tschermakite with cummingtonite overgrowths, and Ti along these diffuse boundaries...ANDESITIC PROGENITOR 7d). Tschermakite with cummingtonite overgrowths also occur within one mingled andesite |  | | Journal (article/letter/editorial) | | Ronnnr J. Tnq,cv Department of Geological Sciences,Virginia Polytechnic Instirute and State University, Blacksburg...composition. The few sampleswe found that had cummingtonite coexisting with cordierite and anthophyllite...provided clues to the behavior of this mineral. Cummingtonite and cordierite have reactedin several samplesto...more rarely gedrite, occurs intergrown with cummingtonite and is observed on the weathered surfaceas long...l0o/o have garnet in addition to cordierite. Cummingtonite occurs as an accessorymineral in some samples |  | | Journal (article/letter/editorial) | | Binghamton University, Binghamton, New York 13902-6000, USA Tel.: +1-607-777-2264 Fax: +1-607-777-2288 E-mail:...Sciences, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061-0420, USA direct...small band at 3669 cm)1 is referred to as the cummingtonite band in Hawthorne et al. (1997) and is attributed...intensity with increasing Ga content. The small cummingtonite band is still perceptible but becomes broader...merging of the dominant A band and the small cummingtonite band may be caused either by a broadening eĀect |  | | Journal (article/letter/editorial) | | BINGHAMTON UNIVERSITY, BINGHAMTON, NY 13902-6000, USA The occurrence of actinolite in magnetite deposits...low-Ca (17 4 Ca 4 14) actinolite; Fe-rich cummingtonite (Ca 507) begins to nucleate at 8608C. At 800^7008C...re-equilibration but strong nucleation of Fe-rich cummingtonite. Similar results were observed at 1kbar, with...re-equilibration to low-Ca actinolite at 790^6008C with cummingtonite nucleation at 8008C and below. The wide variation...of Nevada, Las Vegas, Las Vegas, NV 89154-4010, USA. E-mail: haroldo.lledo@unlv.edu 4 kbar. Considering |  | | Journal (article/letter/editorial) | | Geological Sciences Virginia Polytechnic Institute and State Uniuersity Blacksburg, Virginia 2406I Abstract...Hinrichsen and Both Natuanthophylliteand as cummingtonite-grunerite. conwhich be synthesized could amphibole...phaserelationshipsbetweenthe anthophyllite and the cummingtonite(C2/m) structuresarestill unclear.Although s...nc of 13"-20o for naturally occurring low-Ca cummingtonite-grunerites in the composition range 60-90 mole...Order-disorderapparentlycannot accountfor the boles of the cummingtonite-grunerite Seifertand Virgo (1974)have and Waldbaum |  | | Report (issue) | | riebeckite (commercially called crocidolite), (2) cummingtonite-grunerite (commercially called amosite), (3)...(asbestiform riebeckite) and amosite (asbestiform cummingtonite-grunerite) deposits accounts for most of the...mined at various times in Georgia, North Carolina, Virginia, Maryland, Connecticut, and Massachusetts. Pennsylvania...York New Jersey Pennsylvania Delaware Maryland Virginia North Carolina South Carolina Georgia Alabama...the ultramafic complex, Belvidere Mt., Vermont, USA, in Wright, S.F., ed., Guidebook to field trips in |  | | Journal (article/letter/editorial) | | of xonotlite at Leesburg, Virginia: Am. Mineratr., r0.12-13. CUMMINGTONITE FROM THE MIKONUI RIVER, WESTLAND...Museum of Natural History, New York, N. Y. Cummingtonite has not been recorded from New Zealand, although...shown the presenceof abundant cummingtonite in some of these. The cummingtonite-bearing boulders were collected |  | | Journal (article/letter/editorial) | | in the Chopawamsic Terrane, Piedmont Province, Virginia: Evidence for an Ancient Back-Arc Hydrothermal...Geology, College of William and Mary, Williamsburg, Virginia 23187 Abstract Metamorphosed massive sulfide...portion of the Piedmont physiographic province in Virginia (Fig. 1A). This area has been recognized for an...Formation of the Chopawamsic terrane of central Virginia (Fig. 1A), which comprises a fault-bound assemblage...which is essentially equivalent to the central Virginia volcanic-plutonic belt (Pavlides, 1981). This |  | | Journal (article/letter/editorial) | | University of Maryland, College Park, Maryland 20742, USA ABSTRACT Thirty-one sets of data containing lengths...India and actinolite asbestos from Africa and Virginia. Among them are samples used for National Institute...for mining and 7% for bagging. G. AIRBORNE CUMMINGTONITEāGRUNERITE, SD. Grunerite particles from air...lm Ā¼ 160. H. CUMMINGTONITEāGRUNERITE, SD. This non-fibrous sample of the cummingtoniteāgrunerite mineral...Harper et al. (2008) as cummingtonite but is referred to here as cummingtoniteāgrunerite since its Mg/(Mg |  | | Journal (article/letter/editorial) | | Geological Sciences Virginia Polytechnic Institute and Slate Uniuersity Blacksburg, Virginia 24061 Abstract...of synthetic amphibole, anthophyllite, and cummingtonite-grunerite are small, the experimentalresults...compositional limits compared. Mueller (1960)reported cummingtonite [Fel(Fe + Mg) : 0.23, Mn/(Fe * Mg + Mn) : 0...in the range 550'-600'C based on coexisting cummingtonite-actinolite compositions. At PH,o: Ptot,r andf...Klein (1966) reported both anthrophyllite and cummingtonite from the Wabush Lake area,approximately 20 miles |  | De Angelis, Sarah H., Larsen, Jessica F., Coombs, Michelle L., Utley, James E. P., Dunn, Andrew (2020) Phase equilibrium of a high-SiO2 andesite at $$f_{{0_{2} }}$$f02 ā=āRRO: implications for Augustine Volcano and other high-$$f_{{0_{2} }}$$f02 arc andesites. Contributions to Mineralogy and Petrology, 175 (3) doi:10.1007/s00410-020-1663-6 | Journal (article/letter/editorial) | | accompanied by biotite and small amounts of cummingtonite at T ā¤ 850 Ā°C. The relatively high temperature...99775, USA 2 Alaska Volcano Observatory, U.S. Geological Survey (USGS), Anchorage, AK, USA 3 School...University of Alaska Fairbanks, Fairbanks, AK 99775, USA 5 Tornillo Scientific, Liverpool, UK The 2006...stability for low temperature quartz, biotite, and cummingtonite, likely because of the higher f02 used. Therefore...and ilmenite), Hb amphibole, Q quartz, Cum cummingtonite, Bt biotite, gl glass Starting Material: CH |
|
