Date File Created Name of Creator 4/21/06 Rich Gaschnig GeoRef Data 2005-074680 DN GeoRef TI "Large-volume, low-delta super 18 O rhyolites of the central SnakeRiver plain, Idaho, USA" AU "Boroughs, Scott; Wolff, John; Bonnichsen, Bill; Godchaux, Martha;Larson, Peter" AF "Washington State University, Department of Geology, Pullman, WA,United States USA" AF "Idaho Geological Survey, United States USA" SO "Geology Boulder, vol.33, no.10, pp.821-824, Oct 2005" RL [U RL http://www.gsajournals.org/] IS 0091-7613 CD GLGYBA DE Bruneau-Jarbridge volcanic field; calderas; Cenozoic; crust;eruptions; feldspar group; framework silicates; geochemistry;hydrothermal alteration; Idaho; Idaho Batholith; igneous rocks;isotope ratios; isotopes; Jacks Creek volcanic field; lava; magmatism;major elements; melting; metasomatism; meteoric water; Miocene;Neogene; O-18/O-16; oxygen; pyroclastics; quartz; rhyolite tuff;rhyolites; silica minerals; silicates; Snake River plain; southwesternIdaho; stable isotopes; Tertiary; trace elements; Twin Falls volcanicfield; United States; volcanic features; volcanic fields; volcanicrocks; volcanism; volume; welded tuff; Yellowstone Hot Spot AB "The Miocene Bruneau-Jarbidge and adjacent volcanic fields of thecentral Snake River Plain, southwest Idaho, are dominated byhigh-temperature rhyolitic tuffs and lavas having an aggregate volumeestimated as 7000 km super 3 . Samples from units representing atleast 50% of this volume are strongly depleted in super 18 O, withmagmatic feldspar delta super 18 O sub VSMOW Vienna standard meanocean water values between -1.4ppm and 3.8 ppm. The magnitude of thesuper 18 O depletion and the complete lack of any rhyolites withnormal values 7 ppm-10 ppm combine to suggest that assimilation ormelting of a caldera block altered by near- contemporaneoushydrothermal activity is unlikely. Instead, we envisage generation ofthe high-temperature rhyolites by shallow melting of Idaho Batholithrocks, under the influence of the Yellowstone hotspot, affected byEocene meteoric-hydrothermal events. The seeming worldwide scarcity ofstrongly super 18 O-depleted rhyolites may simply reflect a similarscarcity of suitable crustal protoliths." LA English NT With GSA Data Repository Item 2005162 FE "References: 27; illus. incl. 1 table, sketch map" PY 2005 PT Serial; Analytic CP United States USA CL 02D Isotope geochemistry; 05A Igneous and metamorphic petrology CY "GeoRef, Copyright 2005, American Geological Institute. Referenceincludes data supplied by the Geological Society of America, Boulder,CO, United States" UD 2005 DO 10.1130/G21723.1 AN 2005-074680 Sample Data Item SiO2 Al2O3 TiO2 FeOT MnO CaO MgO K2O Na2O P2O5 Ni Cr Sc V Ba Rb Sr Zr Y Nb Ga Cu Zn Pb La Ce Th Volcanic_Field Rock_Class Rock_Type material D18O D18O Age Max_age Min_age Age Max_age Min_age Location_Name LatDD LongDD Loc_prec State Units wt % wt % wt % wt % wt % wt % wt % wt % wt % wt % ppm ppm ppm ppm ppm ppm ppm ppm ppm ppm ppm ppm ppm ppm ppm ppm ppm per mill per mill Ma Ma Ma Ma Ma Ma DD DD Method 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 2 3 4 4 4 5 5 5 6 6 Sample Name I-3487 Ant Hill Well RLF rhyolite lava volcanic whole rock 2.27 12 6 42.6458 -116.3397 0.01 ID I-3488 Ant Hill Well RLF rhyolite lava volcanic whole rock 2.27 12 6 42.6458 -116.3397 1 ID 02SB-39 Balanced Rock RLF rhyolite lava volcanic whole rock 1.25 12 6 42.55 -114.957 0.1 ID 02SB-40 Balanced Rock RLF rhyolite lava volcanic whole rock 1.25 12 6 42.55 -114.957 0.1 ID I-3410 Balanced Rock RLF rhyolite lava volcanic whole rock 1.85 12 6 42.6475 -114.895 0.01 ID S-487 Bruneau Jasper RLF rhyolite lava volcanic whole rock 3.34 12 6 42.3419 -115.6439 0.01 ID I-404 Buckhorn Ignimbrite ash-flow tuff volcanic whole rock 2.24 12 6 42.1683 -115.9772 0.01 ID I-3388 Castleford Crossing Ign ash-flow tuff volcanic whole rock 1.77 10.3 6 Central Snake River Plain 42.6772 -114.8753 1 ID I-3388 Castleford Crossing Ign ash-flow tuff volcanic whole rock 1.97 10.3 6 Central Snake River Plain 42.6772 -114.8753 0.01 ID I-1122 73.56 13.05 0.47 3 0.05 1.55 0.37 5.33 2.54 0.08 2 6 4 17 1211 206 94 478 63 44.9 18 5 63 28 93 164 28 Cedar Tree RLF rhyolite lava volcanic whole rock 2.28 3.97 10.3 7.5 Central Snake River Plain 42.30150396 -115.6822195 0.001 ID I-1100 75.46 12.38 0.31 2.28 0.03 0.89 0.17 6.41 2.04 0.03 2 0 3 8 795 229 49 397 66 47.6 20 2 70 29 79 181 31 Cougar Point tuff V ash-flow tuff volcanic whole rock 2.86 3.94 12.07 12.11 12.03 Central Snake River Plain 42.0148497 -115.6374062 0.001 ID I-841 73.75 12.79 0.48 3 0.05 1.4 0.41 5.87 2.17 0.08 14 20 10 16 974 211 83 459 56 42.1 19 6 62 25 74 139 28 Cougar Point tuff VII ash-flow tuff volcanic whole rock 0.07 11.8 Central Snake River Plain 42 -115.4 1 ID X-214 74.56 12.56 0.43 2.63 0.05 1.2 0.33 6.05 2.13 0.06 12 15 10 15 939 213 68 438 56 43.8 21 8 55 26 73 143 28 Cougar Point tuff VII ash-flow tuff volcanic whole rock 0.38 11.8 Central Snake River Plain 42 -115.4 1 ID X-72 75.99 12.41 0.3 2.28 0.04 0.54 0.14 5.66 2.61 0.03 16 16 2 5 947 213 38 406 49 44.5 20 9 55 29 89 151 32 Cougar Point tuff X ash-flow tuff volcanic whole rock 11.4 Central Snake River Plain 42 -115.4 1 ID X-116 76.12 12.09 0.31 1.96 0.03 0.76 0.19 6.09 2.4 0.03 17 17 6 0 588 229 29 372 59 44.3 17 8 49 29 91 156 35 Cougar Point tuff XI ash-flow tuff volcanic whole rock 11.59 Central Snake River Plain 41.99529249 -115.4140615 0.001 ID X-174 75.74 12.42 0.28 2.06 0.03 0.75 0.14 6.6 1.96 0.02 18 24 3 5 712 223 29 380 63 44.8 19 2 55 26 94 159 35 Cougar Point tuff XI ash-flow tuff volcanic whole rock 2.62 11.31 Central Snake River Plain 42 -115.4 1 ID X-20 73.84 12.64 0.5 3.08 0.05 1.24 0.37 5.9 2.32 0.08 15 18 7 18 1099 200 68 496 56 42.5 19 7 62 26 86 157 30 Cougar Point tuff XII ash-flow tuff volcanic whole rock -1.26 11.19 Central Snake River Plain 42 -115.4 1 ID X-37 75.68 12.1 0.28 2.2 0.03 0.89 0.14 6.16 2.5 0.02 12 19 6 4 662 209 33 418 78 48.5 19 3 79 31 84 180 31 Cougar Point tuff XIII ash-flow tuff volcanic whole rock 10.94 10.97 10.91 Central Snake River Plain 42 -115.4 1 ID I-810 75.79 12.14 0.33 2.21 0.03 0.95 0.31 5.94 2.27 0.04 2 0 4 11 918 202 50 403 62 41.4 17 7 55 28 87 155 31 Cougar Point tuff XV ash-flow tuff volcanic whole rock 1.04 2.64 10.45 Central Snake River Plain 42.0056838 -115.6353289 0.001 ID I-569 Cougar Pt Tuff III ash-flow tuff volcanic whole rock 3.76 4.71 12.67 12.7 12.64 Central Snake River Plain 42 -115.4 1 ID I-3868 Diamond Creek Rhyolite rhyolite lava volcanic whole rock 8.52 9.58 12 10 Western Snake River Plain 43.1025 -116.2003 0.01 ID I-1060 73.26 12.52 0.46 3.41 0.06 1.6 0.31 5.26 3.04 0.08 1 6 10 9 1124 170 99 521 68 48.8 20 6 78 24 82 145 26 Dorsey Creek RLF rhyolite lava volcanic whole rock 1.48 1.61 8.22 8.6 7.62 Central Snake River Plain 42.2481498 -115.5468907 0.001 ID I-496 73.48 12.78 0.48 3.48 0.07 1.62 0.36 4.97 2.68 0.09 14 21 7 9 1107 158 97 517 68 48.6 20 7 81 23 82 154 23 Dorsey Creek RLF rhyolite lava volcanic whole rock 1.84 2.15 8.22 8.6 7.62 Central Snake River Plain 42.11312203 -115.4667868 0.001 ID I-529 72.83 12.82 0.52 3.81 0.07 1.71 0.37 5.5 2.28 0.09 15 24 5 15 1146 165 106 546 68 49.4 20 5 85 26 81 159 23 Dorsey Creek RLF rhyolite lava volcanic whole rock 1.49 8.22 8.6 7.62 Central Snake River Plain 42.06077115 -115.3997562 0.001 ID I-3843 High Springs Rhyolite rhyolite lava volcanic whole rock 2.28 12 6 43.1656 -115.5146 0.01 ID 02SB-45 71.53 13.16 0.63 3.89 0.06 2.17 0.53 4.9 3 0.13 8 3 12 33 1068 160 121 527 66 45 19 10 79 25 87 155 24 Horse Basin RLF rhyolite lava volcanic whole rock 2.38 10.3 6 Central Snake River Plain 42.71558 -116.06727 0.01 ID 02SB-46 72.2 12.96 0.6 3.76 0.06 1.91 0.5 4.54 3.32 0.14 8 5 6 20 1079 152 115 525 63 45.9 18 10 71 23 75 144 24 Horse Basin RLF rhyolite lava volcanic whole rock 2.36 10.3 6 Central Snake River Plain 42.71558 -116.06727 0.01 ID 02SB-47 72.35 12.94 0.59 3.69 0.07 1.9 0.46 4.56 3.32 0.12 5 3 5 24 1077 152 116 520 57 44.8 18 11 68 24 78 125 22 Horse Basin RLF rhyolite lava volcanic whole rock 10.3 6 Central Snake River Plain 42.71202 -116.03068 0.01 ID 02SB-48 70.92 13.22 0.68 4.26 0.07 2.32 0.59 4.63 3.14 0.16 7 1 10 38 1075 150 131 529 61 44 22 8 76 22 84 139 21 Horse Basin RLF rhyolite lava volcanic whole rock 2.57 10.3 6 Central Snake River Plain 42.68 -116.02958 0.01 ID 02SB-49 71.17 12.84 0.59 3.67 0.07 3.15 0.67 4.48 3.17 0.18 7 3 0 28 1122 148 127 509 59 43.8 20 16 69 25 95 147 23 Horse Basin RLF rhyolite lava volcanic whole rock 10.3 6 Central Snake River Plain 42.68263 -116.0291 0.01 ID 02SB-50 72.32 13 0.58 3.66 0.06 1.86 0.42 4.56 3.41 0.13 6 1 5 20 1096 154 115 520 59 44.3 23 9 66 25 76 143 28 Horse Basin RLF rhyolite lava volcanic whole rock 10.3 6 Central Snake River Plain 42.72453 -116.09752 0.01 ID 02SB-51 72.39 12.78 0.62 3.76 0.07 1.93 0.49 4.72 3.12 0.13 8 2 9 26 1085 156 112 525 61 44.9 21 4 70 20 75 132 24 Horse Basin RLF rhyolite lava volcanic whole rock 10.3 6 Central Snake River Plain 42.72382 -116.0971 0.01 ID 02SB-56 Horse Basin RLF rhyolite lava volcanic whole rock 2.16 10.3 6 Central Snake River Plain 42.70895 -116.04062 0.01 ID 02SB-57 Horse Basin RLF rhyolite lava volcanic whole rock 2.52 10.3 6 Central Snake River Plain 42.69385 -116.04787 0.01 ID I-2132 House Creek Ign ash-flow tuff volcanic whole rock 1.78 10.3 6 Central Snake River Plain 42.147 -114.9542 0.01 ID I-1143 71.2 13.48 0.65 3.98 0.06 2.15 0.63 5.13 2.58 0.13 3 8 11 32 1138 173 118 568 60 42.9 22 7 75 23 85 144 25 Indian Batt RLF rhyolite lava volcanic whole rock 1.99 10.3 7.5 42.25118251 -115.6980102 0.001 ID 01SB-27 71.3 14.25 0.46 2.99 0.07 1.78 0.46 5.39 3.17 0.12 4 0 2 22 1867 100 267 472 49 38.8 22 2 95 24 91 158 9 Jump Creek RLF rhyolite lava volcanic whole rock 12 10 Western Snake River Plain 43.4053 -116.8694 0.01 ID 01SB-28 71.89 14.01 0.43 2.81 0.06 1.68 0.44 5.27 3.29 0.11 5 0 8 15 1671 105 245 404 46 38.1 19 1 89 24 74 139 13 Jump Creek RLF rhyolite lava volcanic whole rock 7.46 12 10 Western Snake River Plain 43.4032 -116.8747 0.01 ID 01SB-29 73.21 13.14 0.44 3.29 0.07 1.65 0.28 4.01 3.79 0.12 5 0 7 20 2103 81 263 473 48 37.9 16 1 90 22 70 125 9 Jump Creek RLF rhyolite lava volcanic whole rock 12 10 Western Snake River Plain 43.3625 -116.947 0.01 ID 01SB-30 77.54 11.21 0.37 2.63 0.05 1.27 0.23 3.5 3.09 0.12 5 0 7 10 1597 72 213 375 44 30.9 16 3 76 15 71 114 8 Jump Creek RLF rhyolite lava volcanic whole rock 8.19 12 10 Western Snake River Plain 43.3588 -116.9461 0.01 ID 01SB-31 71.59 14.26 0.47 3.34 0.05 1.42 0.32 4.6 3.85 0.11 3 0 10 17 1973 100 266 520 49 42.1 21 3 132 19 92 156 9 Jump Creek RLF rhyolite lava volcanic whole rock 12 10 Western Snake River Plain 43.4783 -116.9245 0.01 ID 01SB-32 71.19 13.93 0.47 3.55 0.07 1.64 0.54 4.55 3.93 0.13 6 0 11 8 1951 91 260 519 52 41.6 22 2 105 20 81 151 9 Jump Creek RLF rhyolite lava volcanic whole rock 12 10 Western Snake River Plain 43.4783 -116.9245 0.01 ID 01SB-33 75.89 11.88 0.42 3.07 0.04 1.18 0.3 4.12 2.98 0.12 6 0 6 13 1645 80 220 439 48 36 17 2 60 20 78 137 8 Jump Creek RLF rhyolite lava volcanic whole rock 12 10 Western Snake River Plain 43.4783 -116.9245 0.01 ID 01SB-35 74.53 14.94 0.5 0.63 0.01 1.22 0.12 4.6 3.4 0.05 7 0 11 14 1903 94 272 544 54 42.8 21 1 16 21 93 148 10 Jump Creek RLF rhyolite lava volcanic whole rock 12 10 Western Snake River Plain 43.478 -116.925 0.01 ID I-688 74.44 12.53 0.45 3.31 0.03 1.12 0.19 4.95 2.86 0.12 2 7 7 18 1120 170 93 518 62 48.3 18 3 95 24 72 141 26 Juniper-Clover RLF rhyolite lava volcanic whole rock 0.99 2.82 10.3 7.5 42.37623211 -115.3323478 0.001 ID I-1037 71.95 13.21 0.66 3.96 0.05 1.88 0.58 4.75 2.8 0.16 5 13 4 31 1087 166 109 555 55 41.7 19 7 66 22 73 140 26 Long Draw RLF rhyolite lava volcanic whole rock 1.26 10.3 7.5 42.30212483 -115.6274157 0.001 ID I-1214 70.88 13.49 0.68 4.21 0.06 2.32 0.71 4.97 2.52 0.16 3 12 7 39 1107 170 124 554 58 41.4 18 4 67 21 73 148 26 Long Draw RLF rhyolite lava volcanic whole rock 1.44 10.3 7.5 42.37734497 -115.7519822 0.001 ID I-1350 Lower Crab Creek Ign ash-flow tuff volcanic whole rock 2.44 12 6 42.3579 -115.9774 0.01 ID I-1260 77.37 11.19 0.36 2.66 0.05 0.9 0.17 4.51 2.72 0.07 3 5 4 6 1041 153 68 448 61 45.7 17 4 59 24 85 135 23 Lower Crows Nest Ign ash-flow tuff volcanic whole rock 2.1 2.87 10.3 6 Central Snake River Plain 42.7207 -115.2543 0.01 ID 02SB-76 Perjue Canyon rhyolite lava volcanic whole rock 1.67 12 6 43 -115.5 1 ID I-1056 71.71 12.97 0.64 4.59 0.08 2.03 0.5 4.41 2.94 0.13 4 11 8 19 1099 149 140 556 72 47.3 19 5 97 25 79 136 22 Poison Creek RLF rhyolite lava volcanic whole rock 1.98 10.3 7.5 42.24805625 -115.5504455 0.001 ID 01SB-10 77.11 12.48 0.11 1.32 0.01 0.31 0.02 4.99 3.61 0.04 8 0 3 4 49 145 11 214 53 52.8 24 1 87 29 67 130 14 Reynolds Creek Ign ash-flow tuff volcanic whole rock 12 10 Western Snake River Plain 43.3242 -116.7673 0.01 ID 01SB-6 73.98 13.94 0.13 1.6 0.03 0.31 0.11 6.34 3.53 0.03 6 0 0 0 389 187 31 248 51 61.4 24 0 98 50 83 139 14 Reynolds Creek Ign ash-flow tuff volcanic whole rock 12 10 Western Snake River Plain 43.2988 -116.667 0.01 ID 01SB-7 74.7 12.77 0.1 1.14 0.02 1.63 0.22 5.59 3.8 0.04 6 0 3 0 234 171 29 202 49 58.7 24 3 56 22 50 87 13 Reynolds Creek Ign ash-flow tuff volcanic whole rock 12 10 Western Snake River Plain 43.2988 -116.667 0.01 ID 01SB-8 73.2 14.14 0.13 0.86 0.01 0.49 0.13 6.72 4.23 0.09 8 0 5 10 423 200 29 241 47 61.3 23 3 37 24 65 114 13 Reynolds Creek Ign ash-flow tuff volcanic whole rock 12 10 Western Snake River Plain 43.2988 -116.667 0.01 ID 01SB-05 Reynolds Creek RLF rhyolite lava volcanic whole rock 9.21 12 10 Western Snake River Plain 43.3 -116.75 1 ID 01SB-1 77.17 11.85 0.21 1.89 0.03 0.78 0.11 4.77 3.11 0.07 7 5 6 26 1746 146 82 334 75 37.1 19 1 70 26 129 184 27 Reynolds Creek RLF rhyolite lava volcanic whole rock 12 10 Western Snake River Plain 43.2588 -116.7163 0.01 ID 01SB-3 74.91 12.56 0.24 2.42 0.04 0.97 0.17 5.77 2.9 0.03 4 0 5 3 1481 156 69 372 62 40.9 21 4 93 27 114 203 27 Reynolds Creek RLF rhyolite lava volcanic whole rock 12 10 Western Snake River Plain 43.2634 -116.7182 0.01 ID 01SB-4 74.97 12.59 0.23 2.27 0.03 1.01 0.11 5.65 3.1 0.03 7 0 2 0 1412 162 67 378 63 41.1 18 3 99 35 119 202 28 Reynolds Creek RLF rhyolite lava volcanic whole rock 7.21 9.91 12 10 Western Snake River Plain 43.2622 -116.7132 0.01 ID 01SB-5 74.94 12.65 0.22 2.32 0.03 1.04 0.11 5.72 2.93 0.03 5 0 1 0 1502 163 68 366 61 38.4 21 3 91 29 115 185 28 Reynolds Creek RLF rhyolite lava volcanic whole rock 12 10 Western Snake River Plain 43.2622 -116.7132 0.01 ID 02SB-61 Reynolds Creek RLF rhyolite lava volcanic whole rock 9.57 12 10 Western Snake River Plain 43.26993 -116.69975 0.01 ID 02SB-65 Reynolds Creek RLF rhyolite lava volcanic whole rock 9.89 12 10 Western Snake River Plain 43.29132 -116.70047 0.01 ID I-2863 Rhyolite of Mud Flat road rhyolite lava volcanic whole rock 3.31 12 6 42.7895 -116.2147 0.01 ID I-1074 71.31 12.89 0.66 4.83 0.09 2.18 0.49 4.68 2.73 0.14 2 10 11 10 1073 148 126 557 70 47 20 6 100 21 67 153 22 Sheep Creek RLF rhyolite lava volcanic whole rock 2 9.88 10.34 9.42 Central Snake River Plain 42.40800044 -115.617825 0.001 ID I-1197 71.48 12.91 0.65 4.79 0.09 2.17 0.5 4.54 2.74 0.13 3 9 8 21 1079 152 123 555 70 46.8 22 6 97 22 85 157 21 Sheep Creek RLF rhyolite lava volcanic whole rock 2.24 9.88 10.34 9.42 Central Snake River Plain 42.6259 -115.9074 0.01 ID I-3425 Shoshone Falls RLF rhyolite lava volcanic whole rock 0.36 10.3 6 Central Snake River Plain 42.6051 -114.467 0.01 ID I-1631 Spencer Reservoir Ign ash-flow tuff volcanic whole rock 2.74 12 6 42.8184 -116.0471 0.01 ID I-2207 Three Creek RLF rhyolite lava volcanic whole rock 2.4 12 6 42.1622 -115.2112 0.01 ID I-1138 72 13.18 0.6 3.73 0.06 1.94 0.54 5.59 2.25 0.11 2 6 6 26 1185 177 108 570 63 42.2 22 9 80 22 79 153 25 Triguero Homestead RLF rhyolite lava volcanic whole rock 1.56 10.3 7.5 42.23523435 -115.6961879 0.001 ID I-2475 Upper Brown's Creek Ign ash-flow tuff volcanic whole rock 8.52 9.41 12 10 Western Snake River Plain 42.7895 -116.2147 1 ID I-1269 71.8 13.5 0.64 3.86 0.05 1.79 0.47 4.79 2.96 0.14 2 9 11 26 1057 165 110 564 61 46.1 20 6 70 27 73 147 24 Upper Crows Nest RLF rhyolite lava volcanic whole rock 12 6 42.7 -115.25 1 ID 01SB-11 77.03 12.64 0.11 1.08 0.01 0.35 0.23 5.02 3.52 0.02 9 0 3 2 35 154 13 209 60 52 23 4 72 28 59 122 13 Wilson Creek Ign ash-flow tuff volcanic whole rock 12 6 43.3242 -116.7673 0.01 ID 01SB-12 Wilson Creek Ign ash-flow tuff volcanic whole rock 8.98 12 6 43.3242 -116.7673 1 ID 01SB-13 77.43 12.04 0.1 1.22 0.03 0.36 0.12 5.04 3.63 0.04 6 0 1 6 67 141 13 209 59 52.3 20 3 82 30 49 108 13 Wilson Creek Ign ash-flow tuff volcanic whole rock 12 6 43.3242 -116.7673 0.01 ID 01SB-15 77.96 12.19 0.09 0.63 0 0.43 0.11 4.99 3.57 0.02 6 0 6 0 17 153 11 204 38 53.1 22 2 44 30 38 98 15 Wilson Creek Ign ash-flow tuff volcanic whole rock 12 6 43.3983 -116.7391 0.01 ID 01SB-19 76.44 12.31 0.1 0.93 0.02 0.95 0.33 6.1 2.8 0.02 7 0 6 3 49 149 20 207 67 53.9 24 1 83 32 59 116 16 Wilson Creek Ign ash-flow tuff volcanic whole rock 12 6 43.3589 -116.7349 0.01 ID 01SB-21 76.52 12.5 0.12 1.33 0.02 0.62 0.26 5.74 2.87 0.02 8 0 0 6 60 148 24 206 67 52.4 24 0 89 31 68 118 14 Wilson Creek Ign ash-flow tuff volcanic whole rock 8.53 12 6 43.3585 -116.7336 0.01 ID 02SB-85 Wilson Creek Ign ash-flow tuff volcanic whole rock 8.67 12 6 43.3514 -116.7439 0.01 ID Method Data 1 XRF 299 2 ICPMS_LA:FSP 299 3 ICPMS_LA:QZ 299 4 REG_COR 299 5 REG_COR 2004-068538 6 REG 2005-074680 Normalization Data Item D18O D18O Units Per mill per mill Method Number 2 3 Standard Name NBS-28 UWG-2 Fractionation Data Method Number 2 3 Item 0.05 0.05 Reference data georef# 2004-068538 TI "The Cougar Point Tuff; implications for thermochemical zonation andlongevity of high-temperature, large-volume silicic magmas of theMiocene Yellowstone Hotspot" AU "Cathey, Henrietta E; Nash, Barbara P" AF "University of Utah, Department of Geology and Geophysics, Salt LakeCity, UT, United States USA" SO "Journal of Petrology, vol.45, no.1, pp.27-58, Jan 2004" IS 0022-3530 CD JPTGAD DE Bruneau-Jarbidge volcanic center; Cenozoic; Cougar Point Tuff;geochemistry; high temperature; hot spots; Idaho; igneous rocks;lithogeochemistry; magmas; Miocene; Neogene; Owyhee County Idaho;plate tectonics; pyroclastics; rhyolite tuff; rhyolites; temperature;Tertiary; thermochemical properties; tuff; United States; volcanicrocks; Yellowstone Hot Spot; zoning AB "The 12.7-10.5 Ma Cougar Point Tuff in southern Idaho, USA, consists of10 large-volume <10 super 2 -10 super 3 km super 3 each,high-temperature 800-1000 degrees C, rhyolitic ash-flow tuffserupted from the Bruneau-Farbidge volcanic center of the Yellow-stonehotspot. These tuffs provide evidence for compositional and thermalzonation in pre-eruptive rhyolite magma, and suggest the presence of along-lived reservoir that was tapped by numerous large explosiveeruptions. Pyroxene compositions exhibit discrete compositional modeswith respect to Fe and Mg that define a linear spectrum punctuated byconspicuous gaps. Airfall glass compositions also cluster into modes,and the presence of multiple modes indicates tapping of differentmagma volumes during early phases of eruption. Equilibrium assemblagesof pigeonite and augite are used to reconstruct compositional andthermal gradients in the pre-eruptive reservoir. The recurrence ofidentical compositional modes and of mineral pairs equilibrated athigh temperatures in successive eruptive units is consistent with thepersistence of their respective liquids in the magma reservoir.Recurrence intervals of identical modes range from 0.3 to 0.9 Myr andsuggest possible magma residence times of similar duration. Eruptionages, magma temperatures, Nd isotopes, and pyroxene and glasscompositions are consistent with a long-lived, dynamically evolvingmagma reservoir that was chemically and thermally zoned and composedof multiple discrete magma volumes." LA English FE "References: 57; illus. incl. charts, 9 tables, sketch map" PY 2004 PT Serial; Analytic CP United Kingdom GBR LL "Latitude:N420000,N434000 Longitude:W1150400,W1170200" CL "02C Geochemistry of rocks, soils, and sediments; 05A Igneous andmetamorphic petrology" CY "GeoRef, Copyright 2004, American Geological Institute." UD 200420 AN 2004-068538