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Supplementary Table 1. Compositional groups, typical sample numbers and location with their bulk compositional, mineralogical and petrographic characteristics at different metamorphic grades. Sample #s, Mineral assemblage, Compositio N/E Traverse, Texture Metamorphic Bulk Chemical mode nal GPS and grade Characteristics and Group coordinates other comments mineral chemistry Ms-Chl-Qtz-Ilm-Mag-Gr ± Kfs ± Pl Mode: (Qtz 35-42%, Ms 30 - 33%, Chl 25 - 30%, Pl 5-7%). #1/00, E, Lithology: Chlorite quartz phyllite (minor white 27 o11.268, mica), white mica quartz phyllite (minor chlorite) /88 o38.581 Two compositional and chlorite bearing quartzite. Millimeter to centimeter groups (one richer in scale banding into M- Al 2O3 ~25 wt.%, Muscovite: domain (mica + chlorite Chlorite Normal #187/01, another ~20 Wt.%). rich), grain size 2 - 20 m 187/3, Rocks richer in Paragonite 5%, Pyrophyllite 19%, Celadonite 12%, and Q - domain (quartz - 187/3/ CHAKRA Al 2O3 are relatively Fe-celadonite 13%. feldspar rich), grain size 10 , N, GPS not less ferruginous (see - 50 µm. known Fig 3). Chlorite: XMg (Mg/(Mg+Fe(tot)) = 0.37 - 0.41. Plagioclase: XAn = 0.03 #ID/00,E, Ms-Chl-Qtz-Bt - Pl ± Ilm ± Tur ± Gr 27 o11.268, /88 o38.581 Chl - Qtz - Ms - Ilm -Gr - Tur - Bt - Pl #2/00, E, Two subgroups - 27 o11.465, high Al, low Fe (18 o /88 38.650 - 24 wt% Al 2O3, - Mode: (Qtz 35-42%, Ms 30 - 33%, Bt 15 - 18%, Chl 4.5-5 wt% Fe 2O3) 10 - 12%, Pl 5-7%). Pervasive foliation defined #3/00, E, and low Al, high Fe by biotite, white mica, o 27 11.465, (14.5 - 17 wt% chlorite and occasional o /88 38.692 Al 2O3, 6.0 - 8.0 wt% Muscovite: ilmenite (S 2) almost parallel Fe 2O3). to compositional banding #4/00, E, Some with high Paragonite 10 -15%, Pyrophyllite 22 - 28%, (S 0). S 2 is crenulated to S 3 27 o11.484, MnO (0.37 - 0.59 Celadonite 6 -9%, Fe-celadonite 6-14%. defned by new generation Biotite Normal o /88 38.858 wt%). SiO 2 variable of biotite, ilmenite and indicating Biotite: elongated quartz in Q - #167/01, N, interbanding of domains. Some coarser o 27 26.092, variable amounts of XMg = 0.38, X Fe = 0.45, X Ti = 0.03, X (AlVi) = 0.14. biotite, chlorite as well as /88 o30.888 psammitic material, plagioclase cross cut all TiO 2 relatively Chlorite: foliations and appear to be #176/01,N, constant (0.55 - 0.8 post-tectonic. o 27 24.809, wt% for most XMg (Mg/(Mg+Fe(tot)) = 0.45. /88 o30.935 samples). Plag: #170/01,N, o 27 24.809, XAn = 0.03 /88 o30.925 Chlorite - quartz - plagioclase ± muscovite Muscovite: Paragonite 7 - 12%, Pyrophyllite 16 - 33%, #1/00/A, E, Celadonite 11 - 13%, Fe-celadonite 12%. Foliation defined by chlorite Magnesian 27 o11.268, and white mica; crenulation (Normal - /88 o38.581 MgO ~ 5 wt%. Chlorite: Biotite by second generation white biotite) mica. XMg (Mg/(Mg+Fe(tot)) = 0.65. Plagioclase: XAn = 0.1 Ms - Chl - Qtz - Pl - Grt - Mag - Ilm - Gr. Garnet: Concentric growth zoned with Mn and Ca decreasing to rim compensated by increase of Fe and Mg. Core: Sps 50 Alm 34 Prp 3Grs 13 150 - 200 µm euhedral garnet porphyroblasts set in Rim: external S 2 fabric defined Sps 20 Alm 63 Prp 07 Grs 10 by white mica. Elongate quartz and opaque Muscovite: inclusions near core of garnet define an internal Mn-rich # 1C/00/3, E MnO ~ 0.4 wt%, ~ Paragonite 14%, Pyrophyllite 15%, Celadonite 6%, fabric (? S ) at high angles (Normal + 27 o11.288, 10 x other bulk 1 Biotite Fe-celadonite 15%. to the external fabric. Grt) /88 o38.619 compositions. Coarse plagioclase as well Chlorite: as later generation of mica and chlorite cut across main XMg (Mg/(Mg+Fe(tot)) = 0.47; Mn-rich with 0.5 - foliation. Quartz is coarse, 0.6 wt% MnO (= 10x other rocks). polygonal in Q-domains and elongate in M-domains. Plagioclase porphyroblasts reverse zoned, unlike in other rocks, from An 26 (core) - An 10 (rim). Ms - Qtz - Chl - Bt ± Pl - Ilm ± Grt ± Gr Mode: (Qtz 26-30%, Ms 35-40%, Bt 8-15%, Chl 8%, Grt 1-3%, Pl 5-8%) Garnet preferentially Garnet: Concentrically zoned, typical core: develops in graphitic Alm Prp Grs Sps , typical rim: 72 05 06 17 schists. S2 defined by Alm Prp Grs Sps . Total range found: Alm 81 05 04 10 68- Muscovite, chlorite and Prp Grs Sps . In rocks without plagioclase, #8/00, E, 80 4-16 6-16 2-17 biotite wrap around garnet garnet is more calcic: 27 o11.616, porphyroblasts. Marked Low alumina as well Alm Prp Grs Sps . /88 o39.131; 65-68 03 18-21 14 decrease in modal Normal as high alumina abundance of chlorite in compositions Biotite at contact with garnet: X = 0.28, X = #158/01, N, Mg Fe garnet rich areas. S often represented; some 0.47, X = 0.01, X = 0.24. 2 27 o27.711, Ti (AlVI) forms sigmoidal inclusion Mn rich and Mg rich /88 o31.400 trails in garnet, some Garnet bulk compositions Ilmenite included in garnet has higher Mn content garnets include an inner found without (= 5 mol% pyrophanite vs. 3mol% in matrix). trail of S that is straight profound effects on 1 and truncated by S . mineral assemblages Chlorite: XMg = 0.36 - 0.39, lower than in lower 2 #24/99/1, N, Aluminous, at these grades. grades. 27 o27.292´, Magnesian bulk high Fe /88 o31.63 compositions (e.g. #19/99) Muscovite: have lower modal abundance of garnet Paragonite 11%, Pyrophyllite 21%, Celadonite 6%, compared to Fe-rich (e.g. Fe-celadonite 6%. #24/99) samples. Plagioclase: XAn = 0.1 Ms - Cld - Qtz - Chl - Bt - Ilm ± Gr ± Grt Chloritoid porphyroblasts Mode: (Qtz 35-40%, Cld 12 - 16%, Grt 4-8%, Chl 8 Similar in Mn and may be aligned along S or #7/00/R4 - 16%, Ms 20 - 22%, Bt 8-10%, Pl 6-10%). 2 even lower in Al S foliation. Ilmenite is & 7/00/R/6, E, 3 content to garnet often included in chloritoid. 27 o11.616, Cld: bearing rocks from In one case chloritoid and Ferruginous /88 o39.131 the same outcrop garnet occur in the same (Normal + X = 0.1 Garnet (e.g. #8/00). Fe/Mg Mg thin section but in different Chltd) ratio - higher Fe domains - chloritoid occurs #135/01, E, Chlorite: contents - favor in more muscovite rich GPS not appearance of domains. There is a single known X = 0.25 chloritoid. Mg chloritoid inclusion in a garnet in #135/01. Biotite: X Mg = 0.39, X Ti = 0.04, X (AlVI) = 0.18. Chl - Qtz - Grt - Pl - Bt - Ap - Ilm Garnet: Alm 80 Prp 12 Grs 04 Sps 04 , even richer in almandine (82) Low at the rim. Chlorite - garnet - #10/00, E, Potassic plagioclase rich rock with 27 o11.628, (semi - Biotite: chlorite and biotite defining /88 o39.459; Garnet pelite) S foliation. Euhedral garnet 2 (Normal - X = 0.28, X = 0.55, X = 0.03, X = 0.14. overprints, and sometimes Mg Fe Ti (AlVI) Musc deflects, this foliation. Chlorite: XMg = 0.36. Plagioclase: XAn = 0.15 - 0.17. Ms - Qtz -St - Pl - Bt - Ilm - Grt Muscovite and biotite define foliation (S2). Mode: (Qtz 35 - 44%, Ms 15 - 17%, Bt 18 -22%, St Sigmoidal inclusion trails of 9 - 11%, Grt 5-10%, Pl 5 - 10%). S2, including ilmenites, within staurolite and garnet. Garnet: Foliation wraps around porphyroblasts. Core: Alm 63 Prp 12 Grs 08 Sps 17 , with well preserved growth zoning. Increase of Mn content at the very rim. #17/00, E, Equivalent of low Staurolite Normal 27 o12.064, alumina pelites from Muscovite: /88 o41.397 lower grades. Paragonite 17%, Pyrophyllite 12%, Celadonite 5%, Fe-celadonite 10%. Biotite: XMg = 0.4, X Fe = 0.42, X Ti = 0.02, X (AlVI) = 0.16. Staurolite: XFe = 0.78. Ms -Bt -Grt -St - Ky - fibrolite -Grt - Ilm – Qtz ± Cld, secondary Chl. Some locations contain abundant and strongly zoned Tur. Garnet: Core: Alm 83 Prp 09 Grs 06 Sps 02 , distinctly poorer in Mn and only weakly zoned Muscovite and biotite (XAlm ~ Xprp ~ 0.02). define S 2, garnet and staurolite include sigmoidal Muscovite: trails of S 2, kyanite is coarse prismatic. Paragonite 18%, Celadonite 4.5%, Rare chloritoid inclusion in Fe-celadonite 7.5%. garnet coexisting with Aluminous staurolite. (Normal + #11/00, E, Staurolite Biotite: Tourmaline can define kyanite) folded inclusion trails in XMg = 0.34, X Fe = 0.45, X Ti = 0.05, X (AlVI) = 0.16. staurolite sometimes. Plagioclase: Fibrolite often surrounds garnet, biotite with ilmenite, XAn = 0.2. can be folded into crenulations occasionally. Staurolite: XFe = 0.82 - 0.86 (included chloritoid has X Fe = 0.85). Ms - Bt - Qtz - Pl - Grt - Ilm Garnet: Abundant garnet and Exceptionally rich in Sps and Grs in plagioclase; in spite of high CaO = 3.7 wt% Core: Al as well as Zn content, Calcic #14/00, E, compared to general Staurolite does not appear, (Normal - 27 o12.174, Staurolite range of 0.15 - 0.52 Alm Prp Grs Sps , indicating that its Staurolite) /88 o41.026 50 09 14 27 %. with well preserved growth zoning. appearance is controlled by Ca (e.g. Spear and others Plagioclase rich in An: 1995). XAn = 0.34 Ms - Qtz -St - Pl - Bt - Ilm - Grt Garnet: Core: Alm 73 Prp 05 Grs 13 Sps 09 , Rim: Alm 84 Prp 10 Grs 5.5 Sps 0.5 . Muscovite: #15/00, E, Mn - poor 27 o12.157, Paragonite 17%, Pyrophyllite 12%, Celadonite 5%, (Normal, /88 o41.137 Fe-celadonite 10%.
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  • Minerals of Rockbridge County, Virginia

    Minerals of Rockbridge County, Virginia

    VOL. 40 FEBRUARYJMAY 1994 NO. 1 &2 MINERALS OF ROCKBRIDGE COUNTY, VIRGINIA D. Allen Penick, Jr. INTRODUCTION RockbridgeCountyhas agreatdiversityofrocksandminerals.Rocks withinthecountyrangeingeologic agehmPmxnbrianthroughDevonian (01desttoyoungest)covexingatimespanofatleast 1OOOmilIion years. The county liesmostlywithintheVdeyandRiagePhysi~hich~~ 1). Thisprovinceis underlainbysedimentaryrochcomposedof dolostone, limestone, sandstone, andshale. TheexlMlceastempartofRockbridge County is withintheBlueRidge PhysiowhicPro. This areaisrepre sentedbyallthreemajorrocktypes: sedirnentary,igneous, andmetarnorphic. Theseinclu&Qlostone,qdta,inta~s~neandshale,granite, pmdiorite, andunakite. Ingeneral, theol&strocksarefoundin theeastem portion with youngerrocks outcropping in the westernpart of thecounty o%w2). Mininghasplaydan~tpaainthehistoryofRockbridgeCounty. Indians probably were thefirstco1lectorsof localqu~andquartzitefrom which they shapedprojectilepoints. Important deposits of ironore were mined in the 1800s near the towns of Buena Vista, Goshen, Vesuvius, and in Amoldvalley. Other early minesin thecounty -&manganese, waver- tine-marl, tin, niter (saltpeter), lithographiclimestone, silicasand, andcave orryx Thecounty has been prospected for barite, gibbsite (alumina), gold, silver, limonik(ocher),beryl, Ghalerite (zinc), andilmeniteandmtile(tita- nium), but no production has beenreported for t.Quarriesare still producing dolostone.lirnestone, andquartzitefor constructionaggregate andshale forbrickmanufacture. This report describes 102mineralsandnativeelements
  • Predictive Mineral Discovery COOPERATIVE RESEARCH CENTRE Scale-Integrated Alteration Studies at Kanowna Belle Dr

    Predictive Mineral Discovery COOPERATIVE RESEARCH CENTRE Scale-Integrated Alteration Studies at Kanowna Belle Dr

    predictive mineral discovery COOPERATIVE RESEARCH CENTRE Scale-Integrated Alteration Studies at Kanowna Belle Dr. Glen Masterman and Scott Halley (Placer Dome Asia Pacific) John Walshe (CSIRO) KB Sulfide Evolution KB Sulfur Isotopes YilgarnSulphurIsotopes_AMG by d34s Kanowna Belle 4 to 20.5 (115) -1 to 4 (415) -4 to -1 (175) 1000 -41.6 to -4 (233) 100 dirty 10 zoned clean Au ppm 1 unclassified 0.1 0.01 -8 -4 0 4 8 δ34S N •Dirty pyrite cores with Au, Te, basemetal & Kanowna Belle; Sulfur Isotope values gangue inclusions 40 KB •As-rich and As-poor growth bands 35 •Clean inclusion-free euhedral pyrite 30 2 km 25 KB overgrowths 20 Regional •Late Au, Te & sulfosalt infill (remobilised or 15 •High Au grades correlate with -ve δ34S values in dirty pyrite cores. new addition??) No. of measurements 10 34 5 •δ S values in zoned pyrite are between -2.8 and 2.9 per mil. 0 •Clean pyrite rims are -2.5 to 0.3 per mil. 0 2 4 6 8 -8 -6 -4 -2 10 -12 -10 δ34S •KB pyrites record a history of oxidised fluids early in the evolution of the deposit gradually becoming swamped by reduced fluids. •Regional δ34S values are clustered around 2 per mil KB Alteration Geochemistry Lowes Shoot Alkali Signature (GDD438) Lowes Shoot Pathfinder Signature (GDD438) KB Regional Alkali Halo Muscovite V-rich + alkali feldspar altered samples Albite KB Muscovite-albite tie line 2 km A plot of K/Al vs. Na/Al molar ratios quantifies alteration Pathfinder elements typically associated with Au include W, Mo, mineralogy.
  • Clay Minerals

    Clay Minerals

    CLAY MINERALS CD. Barton United States Department of Agriculture Forest Service, Aiken, South Carolina, U.S.A. A.D. Karathanasis University of Kentucky, Lexington, Kentucky, U.S.A. INTRODUCTION of soil minerals is understandable. Notwithstanding, the prevalence of silicon and oxygen in the phyllosilicate structure is logical. The SiC>4 tetrahedron is the foundation Clay minerals refers to a group of hydrous aluminosili- 2 of all silicate structures. It consists of four O ~~ ions at the cates that predominate the clay-sized (<2 |xm) fraction of apices of a regular tetrahedron coordinated to one Si4+ at soils. These minerals are similar in chemical and structural the center (Fig. 1). An interlocking array of these composition to the primary minerals that originate from tetrahedral connected at three corners in the same plane the Earth's crust; however, transformations in the by shared oxygen anions forms a hexagonal network geometric arrangement of atoms and ions within their called the tetrahedral sheet (2). When external ions bond to structures occur due to weathering. Primary minerals form the tetrahedral sheet they are coordinated to one hydroxyl at elevated temperatures and pressures, and are usually and two oxygen anion groups. An aluminum, magnesium, derived from igneous or metamorphic rocks. Inside the or iron ion typically serves as the coordinating cation and Earth these minerals are relatively stable, but transform- is surrounded by six oxygen atoms or hydroxyl groups ations may occur once exposed to the ambient conditions resulting in an eight-sided building block termed an of the Earth's surface. Although some of the most resistant octohedron (Fig.