Table 1. K-Ar age compilation for rocks collected in southern California rad Sample Mineral Age K2O Ar Published or Location (lat, Quadrangle Rock description No. (Ma) (percent) (percent) Unpublished long) P1-3 -- -- -- -- -- -- Lakeview Lakeview Mountains pluton. Mafic segregations in outer margin. 7.5’ Not dated. P2-3 Biotite 87.8 8.29 81 Unpublished 117˚ 04” 57” Cadiz 15’ Lakeview Mountains pluton. Representative of main tonalite rock 33˚ 47’ 05” type. P3-3 -- -- -- -- -- -- -- Mylonite at mouth of Palm Canyon. Not dated. P4-3 Biotite 59.9 9.58 92 Unpublished 116˚ 29’ 20” Cathedral Cataclasized granitic rock. 1.5 miles north of Cathedral Canyon 33˚ 47’ 28” City 7.5’ Drive on California Highway 111. P5-3 -- --- -- -- -- -- -- Sam Sims pluton. Intersection of Pinyon Crest Road and Pines-to- Palms Highway. P6-3 -- -- -- -- -- -- -- Sam Sims pluton. 1.0 miles east of Pinyon Flat turnoff. Not dated. P7-3 Whole 70.2 3.83 97 Unpublished 116˚ 28’ 42” Toro Peak Ultramylonite. 1.4 miles west of Pinyon Flat. rock 33˚ 34’ 43” 7.5’ P8-3 -- -- -- -- -- -- Toro Peak Mylonite. 1.4 miles west of Pinyon Flat. Sample for whole-rock 7.5’ age. Not dated. P9-3 -- -- -- -- -- -- -- Plutonic rock west of main mylonite on Pines-to-Palms Highway. Not dated. P10-3 -- -- -- -- -- -- -- Thomas Sill. East side of the San Jacinto Fault. Not dated. P11-3 -- -- -- -- -- -- -- Thomas Sill. West side of the San Jacinto Fault. Not dated. P1-5 Biotite 100 8.98 93 Published 117˚ 31’ 34” Corona Biotite-hornblende tonalite-quartz diorite; unnamed pluton. 33˚ 55’ 53” North 7.5’ P2-5 Biotite 97.3 9.17 95 Published 117˚ 29’ 55” Fontana 7.5’ Biotite- hornblende tonalite; unnamed pluton. 34˚ 1’ 51” P3-5 Biotite 103 9.45 95 Published 117˚ 24’ 56” Fontana 7.5’ Biotite- hornblende tonalite; unnamed pluton. 34˚ 1’ 8” P4-5 Biotite 86.7 9.53 89 Published 117˚ 7’ 57” Sunnymead Biotite- hornblende granodiorite; unnamed pluton; foliated, part of 33˚ 54’ 32” 7.5’ generic biotite- hornblende granodiorite unit. P5-5R Biotite 89.7 9.42 93 Published 117˚ 12’ 25” Perris 7.5’ Biotite- hornblende tonalite; unnamed pluton; part of generic 33˚ 51’ 58” biotite- hornblende tonalite unit. P6-5 Biotite 85.4 9.01 89 Published 117˚ 2’ 17” Lakeview Biotite- hornblende granodiorite; unnamed pluton; part of generic 33˚ 47’ 47” 7.5’ biotite- hornblende granodiorite unit. P7-5 Biotite 96.4 9.22 94 Published 117˚ 9’ 38” Romoland Biotite- hornblende tonalite; Domenigoni Valley pluton; isotropic 33˚ 43’ 15” 7.5’ texture. P8-5 Biotite 95.9 9.28 94 Published 117˚ 12’ 19” Romoland Biotite- hornblende tonalite; Domenigoni Valley pluton; isotropic 33˚ 40’ 31” 7.5’ texture. P9-5 Biotite 109 8.72 89 Published 117˚ 16’ 59” Elsinore 7.5’ Biotite granodiorite; Paloma Valley Ring Complex. 33˚ 38’ 53” rad Sample Mineral Age K2O Ar Published or Location Quadrangle Rock description No (Ma) (percent) (percent) Unpublished P10-5 Biotite 109 8.79 90 Published 117˚ 20’ 55” Elsinore 7.5’ Biotite granodiorite; Arroyo del Toro pluton. 33˚ 44’ 22” P11-5 Biotite 99.7 9.39 93 Published 117˚ 18’ 37” Steele Peak Biotite- hornblende -hypersthene monzogranite; Gavilan Ring 33˚ 47’ 0” 7.5’ Complex. P12-5 Biotite 94.7 9.44 91 Published 117˚ 15’ 52” Steele Peak Biotite- hornblende tonalite; Val Verde pluton. 33˚ 49’ 38” 7.5’ P13-5 Biotite 86.8 8.85 91 Published 117˚ 2’ 34” Lakeview Biotite- hornblende tonalite; crudely foliated and somewhat 33˚ 52’ 12” 7.5’ migmatitic appearing; unnamed pluton. P14-5 Biotite 87.9 9.06 93 Published 116˚ 58’ 28” San Jacinto Biotite- hornblende tonalite; crudely foliated; unnamed pluton. 33˚ 49’ 29” 7.5’ P15-5 Biotite 89.8 9.25 90 Published 116˚ 55’ 25” Hemet 7.5’ Biotite- hornblende granodiorite; common large sphene crystals; 33˚ 43’ 54” Hemet pluton. P16-5 Biotite 91.3 9.15 93 Published 116˚ 58’ 11” Hemet 7.5’ Biotite- hornblende granodiorite; interleaved with metasedimentary 33˚ 40’ 16” rocks of Menifee Valley. P17-5 Biotite 89.6 9.47 90 Published 117˚ 5’ 47” Bachelor Biotite granodiorite; isotropic texture; unnamed pluton. 33˚ 34’ 35” Mtn 7.5’ P18-5 Biotite 91.1 8.72 77 Published 117˚ 4’ 58” Winchester Biotite- hornblende tonalite; isotropic texture; Domenigoni Valley 33˚ 38’ 23” 7.5’ pluton. P19-5 Biotite 92.9 9.35 94 Published 117˚ 22’ 15” Riverside Biotite- hornblende tonalite; crudely foliated; Val Verde pluton. 33˚ 54’ 28” East 7.5’ P20-5 Biotite 104 9.22 95 Published 117˚ 27’ 27” Lake Biotite monzogranite; isotropic; relatively fine grained; Cajalco 33˚ 51’ 4” Mathews pluton. 7.5’ P21-5 Biotite 102 9.24 86 Published 117˚ 26’ 44” Riverside Biotite- hornblende tonalite-quartz diorite; unnamed pluton. 33˚ 58’ 57” West 7.5’ P22-5 Biotite 108 8.46 93 Published 117˚ 30’ 51” Corona Biotite granodiorite; isotropic; unnamed pluton. 33˚ 50’ 23” South 7.5’ P23-5 Biotite 89.5 9.35 95 Published 117˚ 20’ 38” San Biotite- hornblende tonalite; near contact with marble, Slover 34˚ 3’ 50” Bernardino Mountain; unnamed pluton. South 7.5’ P24-5 Biotite 82.2 8.96 82 Published 117˚ 13’ 29” Sunnymead Biotite granodiorite; crudely foliated; Box Springs Mountains 33˚ 59’ 14” 7.5’ plutonic complex. P25-5 Biotite 92.4 9.26 90 Published 117˚ 18’ 15” Riverside Biotite- hornblende tonalite; crudely foliated; unnamed pluton. 33˚ 57’ 22” East 7.5’ P26-5 Biotite 95.1 8.98 93 Published 117˚ 23’ 17” Riverside Biotite- hornblende -hypersthene-fayalite granite; isotropic; granite 33˚ 59’ 4” West 7.5’ of Mount Rubidoux. P27-5 Biotite 86.3 9.29 90 Published 116˚ 59’ 8” Beaumont Biotite- hornblende tonalite; sphene bearing; tonalite of Lamb 33˚ 53’ 58” 7.5’ Canyon. rad Sample Mineral Age K2O Ar Published or Location Quadrangle Rock description No (Ma) (percent) (percent) Unpublished P28-5 Biotite 86.1 9.39 95 Published 116˚ 54’ 10” Beaumont Biotite- hornblende tonalite; sphene bearing; unnamed pluton. 33˚ 53’ 47” 7.5’ P29-5 Biotite 81.1 9.33 92 Published 116˚ 51’ 49” Cabazon 7.5’ Biotite- hornblende tonalite; sphene bearing; unnamed pluton. 33˚ 54’ 22” P30-5 Biotite 85.5 9.37 93 Published 116˚ 49’ 12” Lake Fulmor Biotite- hornblende tonalite; sphene bearing; San Jacinto pluton. 33˚ 51’ 11” 7.5’ P31-5 Biotite 83.0 9.02 94 Published 116˚ 46’ 46” Lake Fulmor Biotite- hornblende tonalite; sphene bearing; San Jacinto pluton. 33˚ 48’ 5” 7.5’ P32-5 Biotite 86.3 9.59 97 Published 116˚ 44’ 7” San Jacinto Biotite- hornblende tonalite; sphene bearing; San Jacinto pluton. 33˚ 44’ 59” Peak 7.5’ P33-5 Biotite 86.9 9.59 97 Published 116˚ 45’ 59” Blackburn Biotite- hornblende tonalite; sphene bearing; San Jacinto pluton. 33˚ 42’ 12” Canyon 7.5’ P34-5 Biotite 78.6 9.57 88 Published 116˚ 43’ 32” San Jacinto Biotite- hornblende tonalite; sphene bearing; San Jacinto pluton. 33˚ 51’ 42” Peak 7.5’ P35-5 Biotite 72.8 9.26 85 Published 116˚ 41’ 56” Whitewater Biotite- hornblende tonalite; sphene bearing; unnamed pluton. 33˚ 54’ 11” 7.5’ P36-5 Biotite 70.7 8.69 92 Published 116˚ 38’ 33” Whitewater Biotite- hornblende tonalite; sphene bearing; unnamed pluton. 33˚ 52’ 51” 7.5’ P37-5 Biotite 71.2 9.09 92 Published 116˚ 38’ 24” San Jacinto Biotite- hornblende tonalite; sphene bearing; San Jacinto pluton. 33˚ 48’ 32” Peak 7.5’ P38-5 Biotite 68.0 9.29 90 Published 116˚ 34’ 35” Palm Springs Biotite- hornblende tonalite; foliated; unnamed pluton. 33˚ 48’ 44” 7.5’ P39-5 Biotite 73.0 9.12 94 Published 116˚ 35’ 31” Palm Springs Biotite- hornblende tonalite; foliated; unnamed pluton. 33˚ 46’ 8” 7.5’ P40-5 Biotite 88.0 9.45 96 Published 116˚ 48’ 19” Lake Fulmor Biotite- hornblende tonalite; sphene bearing; San Jacinto pluton. 33˚ 45’ 27” 7.5’ P41-5 Biotite 86.2 9.43 89 Published 116˚ 51’ 39” Lake Fulmor Biotite- hornblende tonalite; sphene bearing; San Jacinto pluton. 33˚ 47’ 56” 7.5’ P42-5 Biotite 87.7 9.57 95 Published 116˚ 55’ 18” San Jacinto Biotite- hornblende tonalite; sphene bearing; San Jacinto pluton. 33˚ 51’ 4” 7.5’ P43-5 Biotite 82.2 9.40 92 Unpublished 116˚ 47’ 51” Cabazon 7.5’ Not used in this report because of a possible sample mix-up with Biotite 80.9 9.40 77 33˚ 53’ 16” sample P48-5, although quite certain of identification. Shown on Biotite 80.0 9.40 94 sample locality map. P44-5 Biotite 101 9.22 94 Published 117˚ 17’ 49” Wildomar Biotite granodiorite; isotropic; unnamed pluton. 33˚ 35’ 58” 7.5’ P45-5 Biotite 103 9.27 90 Published 117˚ 16’ 29” Wildomar Tonalite of Slaughterhouse Canyon. 33˚ 32’ 13” 7.5’ P46-5 Biotite 109 8.85 91 Published 117˚ 21’ 32” Wildomar Biotite granodiorite; isotropic; unnamed pluton. Biotite 107 8.85 92 33˚ 30’ 17” 7.5’ rad Sample Mineral Age K2O Ar Published or Location Quadrangle Rock description No (Ma) (percent) (percent) Unpublished P47-5 Biotite 114 8.97 93 Published 117˚ 25’ 55” Sitton Peak Biotite granodiorite; isotropic; unnamed pluton; Woodson Biotite 115 8.97 94 33˚ 30’ 1” 7.5’ Mountain granodiorite type. P48-5 Biotite 128 8.11 98 Unpublished 117˚ 30’ 26” Cañada Biotite granodiorite; isotropic; unnamed pluton; Woodson 33˚ 35’ 31” Gobernadora Mountain granodiorite type. Not used in report because of a 7.5’ possible sample mix-up with sample P43-5, although quite certain of identification.