TABLE A1. K Ar AGES AND ANALYTICAL DATA FOR WHOLE-ROCK SAMPLES FROM THE CRATER LAKE REGION Sample Map Grid SiO 2 K 2 O

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1 TABLE A1. K Ar AGES AND ANALYTICAL DATA FOR WHOLE-ROCK SAMPLES FROM THE CRATER LAKE REGION Sample Map Grid SiO 2 K 2 O 40 Ar rad Age number label E/N (wt. %) (wt. %) (10-13 mol/g) (%) (ka) Regional volcanism 1177 Basaltic andesite north of Crater Creek, 2.9 km WSW of Crater Springs bck 5834/ ± ± Basaltic andesite of Whitehorse Creek, dike 0.9 km E of creek bwci 6524/ ± ± Andesite south of Dry Butte, plug 1.1 km S of Dry Butte adsi 8679/ ± ± ± 16 mean = 1088 ± Andesite west of Sand Creek, 3.5 km SE of Kerr Notch asw 7774/ ± ± Basaltic andesite east of Annie Falls, 1.1 km E of falls baf 7357/ ± ± ± 50 mean = 651 ± Andesite of Sun Creek valley, 3.0 km S of Sun Notch, 6200' as 7410/ ± ± Basaltic andesite north of Lookout Butte, lava at cinder cone blp 8602/ ± ± Andesite north of Castle Creek, 650 m N of cinder cone 5932' acc 6161/ ± ± Andesite northeast of Annie Falls, 1.1 km NNE of falls aaf 7301/ ± ± ± 19 mean = 517 ± Andesite of Arant Point, 350 m SSE of summit at 6838/ ± ± ± 16 mean = 297 ± Basaltic andesite of Maklaks Crater, E end of summit ridge bmc 8043/ ± ± Basaltic andesite of Whitehorse Bluff, 2.7 km SE of Union Peak bx 6582/ ± ± Basaltic andesite of Desert Cone, 800 m SSW of summit 6837/ ± ± ± 22 mean = 213 ± Basaltic andesite of Oasis Butte, NW side of Oasis Butte plug bo 6182/ ± ± ± 28 mean = 201 ± Basaltic andesite of Bald Crater, 450 m SW of summit 6330/ ± ± Basaltic andesite of Union Peak, 650 m E of summit bu 6424/ ± ± ± ± 22 mean = 164 ± Andesite south of Lookout Butte, lava from cinder cone alb 8789/ ± ± Basaltic andesite northwest of Pumice Flat, 4.0 km ESE of Union Peak bf 6714/ ± ± Basaltic Andesite north of Crater Peak, 2.2 km N of summit bcnp 7318/ ± ± Basaltic andesite south of Crater Peak, 1.1 km S of summit bcsp 7379/ ± ± Andesite of Crater Peak, 1.6 km NW of summit acr 7245/ ± ± ± 11 mean = 136 ± Andesite of Crater Peak, 900 m NE of summit acr 7458/ ± ± ± 12 mean = 98 ± Basaltic Andesite of Red Cone, 3.7 km NW of Red Cone summit br 6577/ ± ± Basalti andesite of Red Cone, 4.6 km WNW of Red Cone summit br 6429/ ± ± ± 14 mean = 80 ± Basaltic andesite of Red Cone, 650 m SW of Red Cone br 6776/ ± ± ± 8 mean = 36 ± 12 OLe18 Andesite of Scott Creek, N side of Scott Creek, 5250' asc 8569/ ± ± Andesite of Timber Crater, 1.8 km W of summit atc 7463/ ± ± Basalt (HAOT), subdued cone 1.6 km ESE of Bald Crater 6505/ ± ± Basalt (HAOT), top of fault scarp 1.4 km ENE of Bald Crater 6495/ ± ± 48 Pre-Mazama volcanics Submerged caldera wall outcrops, undivided, 1290' depth off of Eagle Point su 7196/ ± ± Dacite of Dry Butte, near summit dd 8656/ ± ± ± 18 mean = 1275 ± Dacite of Sand Creek, dome 1.8 km S of Dry Butte dsc 8614/ ± ± Rhyodacite west of Cavern Creek, near summit of dome rcc 8058/ ± ± Dacite west of The Pinnacles, 200 m SW of Maklaks Pass dw 7661/ ± ± Submerged caldera wall outcrops, undivided, 955' depth off of Sentinel Rock su 7608/ ± ± 20 OLe10 Rhyodacite of Pothole Butte, Sun Creek canyon 2.1 km N of Crater Peak rpb 7423/ ± ± Rhyodacite of Pothole Butte, 1.2 km ESE of summit rpb 8735/ ± ± 8 OLe20 Rhyodacite of Scott Creek, dome 6358' 5.2 km SE of Mount Scott rsc 8333/ ± ± 150 OLe16 Rhyodacite of Scott Creek, easternmost dome N of Scott Creek rsc 8739/ ± ± Rhyodacite of Scott Creek, 1.3 km NNW of Dry Butte rsc 8593/ ± ± ± 17 mean = 415 ± 11 Early Mount Mazama (>350 ka) OLe8 Dacite of Mount Scott, SW rim of cirque 900 m W of summit, 8200' ds 7950/ ± ± Dacite of Mount Scott, 3.0 km ENE of summit ds 8326/ ± ± ± 7 OLe15 Dacite of Mount Scott, 5.5 km E of summit ds 8577/ ± ± ± 13 mean = 355 ± Andesite of Phantom Cone, near lake shore 350 m E of Phantom Ship apn 7464/ ± ± ± 8 mean = 403 ± 12

2 TABLE A1. K Ar AGES AND ANALYTICAL DATA FOR WHOLE-ROCK SAMPLES FROM THE CRATER LAKE REGION (continued) Sample Map Grid SiO 2 K 2 O 40 Ar rad Age number label E/N (wt. %) (wt. %) (10-13 mol/g) (%) (ka) Early Mount Mazama (>350 ka) (continued) 218 Andesite of Phantom Cone, caldera wall below Kerr Notch apn 7560/ ± ± Dacite of Chaski Bay, near head of E fork of Annie Creek db 7249/ ± ± ± 12 mean = 382 ± Dacite of Chaski Bay, lake shore below Rim Village db 6953/ ± ± Dacite of Chaski Bay, Castle Crest, 7400' db 7100/ ± ± ± 8 mean = 333 ± Dacite of Chaski Bay?, 918' depth off of Sentinel Rock db? 7608/ ± ± 10 Mount Mazama ~ ka 836 Andesite of Kerr Notch, near lake shore N of Redcloud Cliff ak 7712/ ± ± ± 12 mean = 341 ± Andesite of Kerr Notch, near lake shore at Cloudcap Bay ak 7708/ ± ± Andesite of Kerr Notch, 3.1 km S of Mount Scott ak 8010/ ± ± ± 11 mean = 315 ± Andesite of Kerr Notch, near base of cliff 400 m SSE of Applegate Peak ak 7341/ ± ± ± mean = 307 ± Andesite of Kerr Notch, lithic block in cinder cone for andesite of Scott Creek ak 8178/ ± ± ± 9 mean = 306 ± Andesite of Kerr Notch, caldera wall E of Sun Notch ak 7457/ ± ± ± 9 mean = 225 ± Dacite of Sentinel Rock, caldera wall N of Redcloud Cliff dr 7722/ ± ± ± 8 mean = 336 ± Dacite of Sentinel Rock, caldera wall 600 m S of Sentinel Rock dr 7662/ ± ± ± ± ± 8 mean = 306 ± Andesite below Rim Village, lake shore below Discovery Point arv 6863/ ± ± Andesite below Rim Village, caldera wall below Rim Village arv 6951/ ± ± Andesite west of Fumarole Bay, lake shore SW of Fumarole Bay af 6825/ ± ± Dacite of Munson Ridge, 250 m ESE of Munson Point dm 6912/ ± ± Andesite of Cloudcap Bay, lowest unit ac flow in caldera wall N of Redcloud Cliff ac 7721/ ± ± Andesite of Cloudcap Bay, highest unit ac flow in caldera wall N of Redcloud Cliff ac 7741/ ± ± ± 15 mean = 231 ± 6 Mount Mazama ~ ka 1014 Andesite of Applegate Peak, subglacial flow in caldera wall at Wineglass aa 7739/ ± ± Andesite of Applegate Peak, caldera wall at Grotto Cove aa 7752/ ± ± ± 7 mean = 313 ± Andesite of Applegate Peak, 700 m SSW of Garfield Peak, top unit aa flow aa 7134/ ± ± ± 16 mean = 269 ± Andesite of Applegate Peak, 2.4 km WSW of Rim Village aa 6754/ ± ± ± 12 mean = 258 ± Andesite of Applegate Peak, caldera rim 350 m NW of Rim Village aa 6948/ ± ± ± 14 mean = 258 ± Andesite of Applegate Peak, caldera rim 1.1 km S of Sentinel Rock, top flow aa 7666/ ± ± Andesite of Applegate Peak, caldera rim S of Dutton Cliff, top flow aa 7505/ ± ± ± 9 mean = 244 ± Andesite of Applegate Peak, caldera wall 1.0 km S of Sentinel Rk., basal flow aa 7650/ ± ± Andesite of Applegate Peak, ridge 300 m S of Applegate Peak, top flow aa 7316/ ± ± Andesite of Applegate Peak?, 700' depth off of Skell Head aa? 7690/ ± ± Andesite of Garfield Peak, 50 m SW of summit ag 7163/ ± ± ± 13 mean = 224 ± Dacite north of Castle Creek, 6.7 km W of Discovery Point dcn 6163/ ± ± ± 6 mean = 216 ± 4 Mount Mazama ~ ka 1303 Andesite east of Munson Valley, 4.0 km S of Garfield Peak amv 7145/ ± ± Andesite of Llao Bay, lower unit, near lake shore W of Llao Rock all 7055/ ± ± ± 13 mean = 172 ± 11

3 TABLE A1. K Ar AGES AND ANALYTICAL DATA FOR WHOLE-ROCK SAMPLES FROM THE CRATER LAKE REGION (continued) Sample Map Grid SiO 2 K 2 O 40 Ar rad Age number label E/N (wt. %) (wt. %) (10-13 mol/g) (%) (ka) Mount Mazama ~ ka (continued) Andesite of Llao Bay, lower unit, 91 m depth E of Llao Rock all 7119/ ± ± Andesite of Llao Bay, lower unit, lake shore 150 m S of Devils Backbone all 6891/ ± ± ± 12 mean = 150 ± Andesite of Llao Bay, lower unit, 59 m depth E of Llao Rock all 7117/ ± ± Andesite of Llao Bay, lower unit, near lake shore W of Pumice Point all 7297/ ± ± ± 28 mean = 122 ± Andesite of Llao Bay, lower unit, near lake shore 500 m E of Llao Rock all 7123/ ± ± ± 33 mean = 109 ± 19 OLe4 Andesite of Roundtop, roadcut on N side of Roundtop ar 7693/ ± ± Andesite of Merriam Point, caldera wall at Llao Bay am 6986/ ± ± Andesite of Llao Bay, upper unit, caldera wall W of Pumice Point alu 7298/ ± ± ± 10 mean = 106 ± Dacite of Steel Bay, caldera wall W of Pumice Point dsb 7308/ ± ± ± 8 mean = 116 ± Dacite of Steel Bay, caldera wall below Llao Rock dsb 7072/ ± ± Dacite east of Palisade Point, caldera wall near E end of Palisade flow dpe 7642/ ± ± ± 7 mean = 111 ± Andesite of the boat landing, caldera wall above lake trail abl 7444/ ± ± 10 Mount Mazama ~80 40 ka 1190 Andesite west of Red Cone, 6.1 km W of Red Cone summit arw 6216/ ± ± Andesite of the west wall, ice-rafted block(?), 1020' depth off of Palisade Point aww 7515/ ± ± Andesite of the west wall, caldera wall 850 m ENE of Hillman Peak aww 6865/ ± ± ± ± 13 mean = 70 ± 4 OLe5 Andesite of Grotto Cove, roadcut 850 m SE of Roundtop agc 7767/ ± ± 10 OLe6 Andesite of Grotto Cove, roadcut 1.9 km SE of Roundtop agc 7817/ ± ± ± 8 mean = 68 ± Dacite of Pumice Castle, lava in caldera wall at Steel Bay dc 7240/ ± ± Dacite of Pumice Castle, highest caldera wall lava 300 m S of Pumice Castle dc 7738/ ± ± ± Basaltic andesite of Hillman Peak, 250 m NW of summit bhi 6811/ ± ± Andesite of Hillman Peak, 150 m W of summit ah 6788/ ± ± ± 10 mean = 61 ± Andesite south of The Watchman, caldera rim 150 m NE of Devils Backbone atw 6877/ ± ± Andesite south of The Watchman, 2.1 km SW of The Watchman summit atw 6646/ ± ± Andesite south of The Watchman, caldera wall 500 m N of Discovery Point atw 6812/ ± ± Andesite of Devils Backbone, 4.4 km NW of Hillman Peak ad 6527/ ± ± ± 9 mean = 75 ± Dacite of The Watchman, N roadcut in The Watchman flow dwf 6718/ ± ± Andesite of Lightning Spring, 2.2 km southwest of The Watchman summit als 6603/ ± ± ± 9 mean = 47 ± Andesite of Pumice Point, caldera wall E of Pumice Point apu 7335/ ± ± Andesite of Steel Bay, caldera wall below E face of Llao Rock asb 7088/ ± ± ± 8 mean = 43 ± 6 OLe3 Andesite of Steel Bay, roadcut above Steel Bay asb 7290/ ± ± ± 8 mean = 42 ± 6 UTM grid explanation: E = easting to 10 m ; N = northing to 10 m ; e.g., #1177 is , in meters (UTM zone 10). Mean ages are weighted means of ages calculated for individual Ar analyses weighted by the inverse of the variance of each measurement.

4 TABLE A2. 40 Ar/ 39 Ar AGES FOR ROCKS FROM THE CRATER LAKE REGION Sample Eruptive unit Map label Grid SiO 2 Plateau Plateau error Isochron error Isochron error number E/N age age intercept (10 m) (%)[steps] (ka) (ka) (ka) (ka) 143 Andesite of Llao Bay, upper unit, caldera alu 7298/ [5 of 11] wall west of Pumice Point Basaltic andesite of Red Cone, 650 m br 6776/ [8 of 11] southwest of Red Cone Dacite of Chaski Bay, Castle Crest at db 7100/ [7 of 16] ' elevation Rhyodacite of Sharp Peak, Sharp Peak rs 8099/ [13 of 17] dome Andesite of Kerr Notch, lithic block in asc(ak) 8178/ [11 of 14] cinder cone for andesite of Scott Creek Andesite of Timber Crater, 1.8 km west of atc 7463/ [11 of 15] summit Basaltic andesite of Scoria Cone, Annie bsc 7254/ [9 of 11] Falls Rhyodacite of Bear Bluff, summit of dome rbb 6873/ [11 of 13] Andesite of the gaging station, lake shore ags 7435/ [13 of 14] by gage 5834 OLe-18 Andesite of Scott Creek, 5250' elevation on north side of Scott Creek asc 8569/ [7 of 12] UTM grid explanation: E = easting to 10 m ; N = northing to 10 m ; e.g., #143 is , in meters (UTM zone 10). *Note to reviewers: The values for this sample have been misplaced and will be provided in the final version.

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