856:
248:
34:
41:
240:
879:
The San Juan volcanic field has been a historically important mining district, producing lead, zinc, copper, gold, and silver. The ores were mostly deposited in and near calderas that experienced significant postcaldera activity. Ore veins were concentrated in fractures associated with caldera
1245:
Sliwinski, J. T.; Bachmann, O.; Dungan, M. A.; Huber, C.; Deering, C. D.; Lipman, P. W.; Martin, L. H. J.; Liebske, C. (May 2017). "Rapid pre-eruptive thermal rejuvenation in a large silicic magma body: the case of the
Masonic Park Tuff, Southern Rocky Mountain volcanic field, CO, USA".
164:
The region began with many composite volcanoes that became active between 35 and 40 million years ago, with peak activity in the time period around 35-30 million years ago. Around this time the activity began to include explosive ash-flow eruptions. Many of these volcanoes experienced
208:
of the original magma. The precaldera intermediate volcanic rocks include the
Conejos Formation in the southeastern part of the field. Intermediate volcanism did not cease with caldera eruptions, and included such voluminous intermediate volcanic rocks as the Huerto Andesite.
1217:
Lipman, Peter W.; Dungan, Michael A.; Brown, Laurie L.; Deino, Alan (1 August 1996). "Recurrent eruption and subsidence at the
Platoro caldera complex, southeastern San Juan volcanic field, Colorado: New tales from old tuffs".
889:
1043:
Colucci, M. T.; Dungan, M. A.; Ferguson, K. M.; Lipman, P. W.; Moorbath, S. (30 July 1991). "Precaldera lavas of the southeast San Juan
Volcanic Field: Parent magmas and crustal interactions".
1191:
Lipman, Peter W.; McIntosh, William C.; Zimmerer, Matthew J. (2013). "From ignimbrite to batholith, northeastern San Juan
Mountains, ColoradoBonanza, Cochetopa Park, and North Pass calderas".
75:
161:
geologic time. There are approximately fifteen calderas known in the San Juan
Volcanic Fields; however, it is possible that there are two or even three more in the region.
855:
946:
Lipman, Peter W.; Steven, Thomas A.; Mehnert, Harald H. (1970-08-01). "Volcanic
History of the San Juan Mountains, Colorado, as Indicated by Potassium–Argon Dating".
1000:
Lipman, P.W.; Doe, B.R.; Hedge, C.E.; Steven, T.A. (1978). "Petrologic evolution of the San Juan volcanic field, southwestern
Colorado: Pb and Sr isotope evidence".
1385:
1395:
1351:
Steven, Thomas A.; Luedke, Robert G.; Lipman, Peter W. (1974). "Relation of mineralization to calderas in the San Juan volcanic field, southwestern
Colorado".
1106:
Kennedy, Ben; Wilcock, Jack; Stix, John (October 2012). "Caldera resurgence during magma replenishment and rejuvenation at Valles and Lake City calderas".
33:
880:
activity and in postcaldera intrusive bodies. The greatest mineralization took place near the youngest and most silicic intrusions of each caldera cycle.
247:
1312:"An ignimbrite caldera from the bottom up: Exhumed floor and fill of the resurgent Bonanza caldera, Southern Rocky Mountain volcanic field, Colorado"
1430:
1390:
819:
776:
647:
604:
561:
514:
471:
428:
338:
295:
733:
690:
383:
1380:
894:
1375:
1283:
Varga, Robert J.; Smith, Brian M. (1984). "Evolution of the Early
Oligocene Bonanza Caldera, northeast San Juan Volcanic Field, Colorado".
899:
1415:
1425:
1455:
1420:
1072:"Contemporaneous Trachyandesitic and Calc-alkaline Volcanism of the Huerto Andesite, San Juan Volcanic Field, Colorado, USA"
1445:
1400:
68:
1450:
1440:
1410:
1405:
252:
1435:
1231:
967:
1021:
205:
1143:
Geologic Map of the Central San Juan Caldera Cluster, Southwestern Colorado: Geologic Investigations Series
277:
128:
149:
in southwestern Colorado. It consists mainly of volcanic rocks that form the largest remnant of a major
1193:
Classic Concepts and New DirectionsExploring 125 Years of GSA Discoveries in the Rocky Mountain Region
1323:
1009:
955:
150:
925:
146:
1140:
Robinson, Joel E.; Dillon R. Dutton; David W. Ramsey; Peter W. Lipman; Tracey J. Felger (2006).
1025:
971:
549:
225:
1331:
1292:
1263:
1255:
1227:
1196:
1115:
1086:
1052:
1017:
963:
554:
166:
256:
233:
154:
1327:
1013:
959:
373:
133:
1369:
1071:
867:
859:
1268:
1091:
1259:
1200:
1119:
1029:
975:
834:
821:
791:
778:
748:
735:
705:
692:
662:
649:
619:
606:
576:
563:
529:
516:
486:
473:
443:
430:
398:
385:
353:
340:
310:
297:
90:
77:
1296:
239:
229:
193:
189:
182:
1310:
Lipman, Peter W.; Zimmerer, Matthew J.; McIntosh, William J. (2015-12-01).
217:
158:
115:
1336:
1311:
890:
List of large volume volcanic eruptions in the Basin and Range Province
221:
213:
170:
1056:
1212:
1210:
863:
1141:
1070:
Parat, Fleurice; Dungan, Michael A.; Lipman, Peter W. (1 May 2005).
926:"Calderas of the San Juan Volcanic Field, Southwestern Colorado"
201:
197:
1232:
10.1130/0016-7606(1996)108<1039:REASAT>2.3.CO;2
232:. It is usually interpreted as a partial melt of the lower
228:, producing both low-silica alkaline flows and high-silica
968:
10.1130/0016-7606(1970)81[2329:VHOTSJ]2.0.CO;2
1022:
10.1130/0016-7606(1978)89<59:PEOTSJ>2.0.CO;2
181:
The San Juan volcanic field experienced two phases of
16:
Volcanic field in southwestern Colorado, United States
196:
Period. It produced largely intermediate composition
1186:
1184:
1182:
1180:
932:. Washington, DC: U.S. Government Printing Office.
127:
122:
111:
106:
67:
62:
21:
1178:
1176:
1174:
1172:
1170:
1168:
1166:
1164:
1162:
1160:
40:
8:
1045:Journal of Geophysical Research: Solid Earth
924:Steven, Thomas A.; Lipman, Peter W. (1976).
188:The earlier volcanism took place during the
1146:. Vol. I-2799. U.S. Geological Survey
930:U.S. Geological Survey Professional Papers
18:
1335:
1267:
1248:Contributions to Mineralogy and Petrology
1090:
1135:
1133:
1131:
1129:
995:
993:
991:
989:
987:
985:
854:
267:
246:
238:
153:field that covered most of the southern
910:
169:, resulting in the fifteen to eighteen
1386:Extinct volcanoes of the United States
1002:Geological Society of America Bulletin
948:Geological Society of America Bulletin
1396:Landforms of Mineral County, Colorado
920:
918:
916:
914:
200:and breccias, together with ash flow
7:
212:The later volcanism took place from
243:Cochetopa Dome (Cochetopa Caldera).
236:that was erupted onto the surface.
14:
224:Period. It was characterized by
39:
32:
1431:Geologic formations of Colorado
1285:Journal of Geophysical Research
1391:Geology of the Rocky Mountains
1:
1381:San Juan Mountains (Colorado)
936:: 1–35. Retrieved 2012-05-16.
895:San Juan Mountains (Colorado)
1376:Volcanic fields of Colorado
900:Volcanic fields of Colorado
870:in San Juan Volcanic Field.
809:
766:
723:
680:
637:
594:
547:
504:
461:
416:
371:
328:
285:
1472:
810:
767:
724:
681:
638:
595:
548:
505:
462:
417:
372:
329:
286:
253:Colorado State Highway 114
1260:10.1007/s00410-017-1351-3
1120:10.1007/s00445-012-0641-x
26:
1092:10.1093/petrology/egi003
255:near Cochetopa Dome and
1416:Oligocene North America
1297:10.1029/JB089iB10p08679
1108:Bulletin of Volcanology
642:Treasure Mountain Group
143:San Juan volcanic field
47:San Juan volcanic field
22:San Juan volcanic field
1426:Pliocene North America
871:
333:Snowshoe Mountain Tuff
260:
244:
91:37.89333°N 106.77444°W
1456:Volcanoes of Colorado
1421:Miocene North America
1353:J. Res. US Geol. Surv
1201:10.1130/2013.0033(14)
858:
250:
242:
173:in the region today.
1446:Calderas of Colorado
1079:Journal of Petrology
866:rock specimen, from
596:Uncompahgre-San Juan
509:Carpenter Ridge Tuff
378:Nelson Mountain Tuff
96:37.89333; -106.77444
53:Location in Colorado
1401:Oligocene volcanism
1328:2015Geosp..11.1902L
1269:20.500.11850/216533
1051:(B8): 13413–13434.
1014:1978GSAB...89...59L
960:1970GSAB...81.2329L
831: /
788: /
745: /
728:Saguache Creek Tuff
702: /
659: /
616: /
573: /
526: /
483: /
440: /
395: /
350: /
307: /
177:Phases of Volcanism
87: /
1451:Oligocene calderas
1441:Paleogene Colorado
1411:Pliocene volcanism
1337:10.1130/GES01184.1
872:
599:Sapinero Mesa Tuff
421:Cebolla Creek Tuff
290:Sunshine Peak Tuff
261:
245:
151:composite volcanic
147:San Juan Mountains
63:Highest point
1406:Miocene volcanism
1057:10.1029/91JB00282
853:
852:
685:Masonic Park Tuff
226:bimodal volcanism
171:caldera volcanoes
139:
138:
1463:
1436:Neogene Colorado
1361:
1360:
1348:
1342:
1341:
1339:
1322:(6): 1902–1947.
1307:
1301:
1300:
1280:
1274:
1273:
1271:
1242:
1236:
1235:
1226:(8): 1039–1055.
1214:
1205:
1204:
1188:
1155:
1154:
1152:
1151:
1137:
1124:
1123:
1114:(8): 1833–1847.
1103:
1097:
1096:
1094:
1076:
1067:
1061:
1060:
1040:
1034:
1033:
997:
980:
979:
954:(8): 2329–2352.
943:
937:
922:
846:
845:
843:
842:
841:
836:
835:38.34°N 106.23°W
832:
829:
828:
827:
824:
814:Thorn Ranch Tuff
806:33.12 ± 0.03 Ma
803:
802:
800:
799:
798:
793:
792:38.32°N 106.08°W
789:
786:
785:
784:
781:
760:
759:
757:
756:
755:
750:
749:38.20°N 106.54°W
746:
743:
742:
741:
738:
717:
716:
714:
713:
712:
707:
706:37.70°N 106.69°W
703:
700:
699:
698:
695:
674:
673:
671:
670:
669:
664:
663:37.35°N 106.53°W
660:
657:
656:
655:
652:
631:
630:
628:
627:
626:
621:
620:37.96°N 107.53°W
617:
614:
613:
612:
609:
591:27.45 ± 0.05 Ma
588:
587:
585:
584:
583:
578:
577:37.76°N 106.94°W
574:
571:
570:
569:
566:
555:Fish Canyon Tuff
544:27.45 ± 0.05 Ma
541:
540:
538:
537:
536:
531:
530:37.82°N 106.91°W
527:
524:
523:
522:
519:
498:
497:
495:
494:
493:
488:
487:37.67°N 106.94°W
484:
481:
480:
479:
476:
466:Watson Park Tuff
455:
454:
452:
451:
450:
445:
444:38.01°N 107.97°W
441:
438:
437:
436:
433:
410:
409:
407:
406:
405:
400:
396:
393:
392:
391:
388:
365:
364:
362:
361:
360:
355:
354:37.76°N 106.94°W
351:
348:
347:
346:
343:
325:22.93 ± 0.02 Ma
322:
321:
319:
318:
317:
312:
311:38.03°N 107.38°W
308:
305:
304:
303:
300:
268:
264:Notable calderas
167:caldera collapse
102:
101:
99:
98:
97:
92:
88:
85:
84:
83:
80:
43:
42:
36:
19:
1471:
1470:
1466:
1465:
1464:
1462:
1461:
1460:
1366:
1365:
1364:
1350:
1349:
1345:
1309:
1308:
1304:
1282:
1281:
1277:
1244:
1243:
1239:
1216:
1215:
1208:
1190:
1189:
1158:
1149:
1147:
1139:
1138:
1127:
1105:
1104:
1100:
1074:
1069:
1068:
1064:
1042:
1041:
1037:
999:
998:
983:
945:
944:
940:
923:
912:
908:
886:
877:
875:Economic Impact
839:
837:
833:
830:
825:
822:
820:
818:
817:
796:
794:
790:
787:
782:
779:
777:
775:
774:
753:
751:
747:
744:
739:
736:
734:
732:
731:
710:
708:
704:
701:
696:
693:
691:
689:
688:
667:
665:
661:
658:
653:
650:
648:
646:
645:
624:
622:
618:
615:
610:
607:
605:
603:
602:
581:
579:
575:
572:
567:
564:
562:
560:
559:
534:
532:
528:
525:
520:
517:
515:
513:
512:
491:
489:
485:
482:
477:
474:
472:
470:
469:
448:
446:
442:
439:
434:
431:
429:
427:
426:
422:
403:
401:
399:38.2°N 106.75°W
397:
394:
389:
386:
384:
382:
381:
358:
356:
352:
349:
344:
341:
339:
337:
336:
315:
313:
309:
306:
301:
298:
296:
294:
293:
274:Associated tuff
266:
257:Cochetopa Hills
220:in ages of the
206:differentiation
179:
155:Rocky Mountains
145:is part of the
118:, United States
95:
93:
89:
86:
81:
78:
76:
74:
73:
58:
57:
56:
55:
54:
51:
50:
49:
48:
44:
17:
12:
11:
5:
1469:
1467:
1459:
1458:
1453:
1448:
1443:
1438:
1433:
1428:
1423:
1418:
1413:
1408:
1403:
1398:
1393:
1388:
1383:
1378:
1368:
1367:
1363:
1362:
1343:
1302:
1275:
1237:
1206:
1156:
1125:
1098:
1085:(5): 859–891.
1062:
1035:
981:
938:
909:
907:
904:
903:
902:
897:
892:
885:
882:
876:
873:
851:
850:
849:33.6 ± 0.3 Ma
847:
840:38.34; -106.23
815:
812:
808:
807:
804:
797:38.32; -106.08
772:
769:
765:
764:
761:
754:38.20; -106.54
729:
726:
722:
721:
718:
711:37.70; -106.69
686:
683:
679:
678:
675:
668:37.35; -106.53
643:
640:
636:
635:
634:27.5 ± 0.5 Ma
632:
625:37.96; -107.53
600:
597:
593:
592:
589:
582:37.76; -106.94
557:
552:
546:
545:
542:
535:37.82; -106.91
510:
507:
503:
502:
499:
492:37.67; -106.94
467:
464:
460:
459:
456:
449:38.01; -107.97
424:
423:Rat Creek Tuff
419:
415:
414:
413:26.4 ± 0.5 Ma
411:
379:
376:
370:
369:
368:26.5 ± 0.3 Ma
366:
359:37.76; -106.94
334:
331:
330:Creede Caldera
327:
326:
323:
316:38.03; -107.38
291:
288:
284:
283:
280:
275:
272:
265:
262:
178:
175:
157:in the Middle
137:
136:
134:Volcanic field
131:
125:
124:
120:
119:
113:
109:
108:
104:
103:
71:
65:
64:
60:
59:
52:
46:
45:
38:
37:
31:
30:
29:
28:
27:
24:
23:
15:
13:
10:
9:
6:
4:
3:
2:
1468:
1457:
1454:
1452:
1449:
1447:
1444:
1442:
1439:
1437:
1434:
1432:
1429:
1427:
1424:
1422:
1419:
1417:
1414:
1412:
1409:
1407:
1404:
1402:
1399:
1397:
1394:
1392:
1389:
1387:
1384:
1382:
1379:
1377:
1374:
1373:
1371:
1358:
1354:
1347:
1344:
1338:
1333:
1329:
1325:
1321:
1317:
1313:
1306:
1303:
1298:
1294:
1291:(B10): 8679.
1290:
1286:
1279:
1276:
1270:
1265:
1261:
1257:
1253:
1249:
1241:
1238:
1233:
1229:
1225:
1221:
1213:
1211:
1207:
1202:
1198:
1194:
1187:
1185:
1183:
1181:
1179:
1177:
1175:
1173:
1171:
1169:
1167:
1165:
1163:
1161:
1157:
1145:
1144:
1136:
1134:
1132:
1130:
1126:
1121:
1117:
1113:
1109:
1102:
1099:
1093:
1088:
1084:
1080:
1073:
1066:
1063:
1058:
1054:
1050:
1046:
1039:
1036:
1031:
1027:
1023:
1019:
1015:
1011:
1007:
1003:
996:
994:
992:
990:
988:
986:
982:
977:
973:
969:
965:
961:
957:
953:
949:
942:
939:
935:
931:
927:
921:
919:
917:
915:
911:
905:
901:
898:
896:
893:
891:
888:
887:
883:
881:
874:
869:
865:
861:
857:
848:
844:
816:
813:
805:
801:
773:
770:
762:
758:
730:
727:
719:
715:
687:
684:
676:
672:
644:
641:
633:
629:
601:
598:
590:
586:
558:
556:
553:
551:
543:
539:
511:
508:
500:
496:
468:
465:
457:
453:
425:
420:
412:
408:
404:38.2; -106.75
380:
377:
375:
367:
363:
335:
332:
324:
320:
292:
289:
281:
279:
276:
273:
270:
269:
263:
258:
254:
249:
241:
237:
235:
231:
227:
223:
219:
215:
210:
207:
203:
199:
195:
191:
186:
184:
176:
174:
172:
168:
162:
160:
156:
152:
148:
144:
135:
132:
130:
129:Mountain type
126:
121:
117:
114:
110:
105:
100:
72:
70:
66:
61:
35:
25:
20:
1356:
1352:
1346:
1319:
1315:
1305:
1288:
1284:
1278:
1251:
1247:
1240:
1223:
1220:GSA Bulletin
1219:
1192:
1148:. Retrieved
1142:
1111:
1107:
1101:
1082:
1078:
1065:
1048:
1044:
1038:
1008:(1): 59–82.
1005:
1001:
951:
947:
941:
933:
929:
878:
868:Idarado Mine
860:Chalcopyrite
771:Bonanza Tuff
211:
187:
180:
163:
142:
140:
838: /
795: /
752: /
709: /
666: /
623: /
580: /
533: /
490: /
463:South River
447: /
402: /
357: /
314: /
278:Coordinates
204:reflecting
192:age of the
94: /
82:106°46′28″W
69:Coordinates
1370:Categories
1359:: 405–409.
1150:2010-05-03
906:References
725:North Pass
251:Aerial of
79:37°53′36″N
1316:Geosphere
1254:(5): 30.
1030:0016-7606
976:0016-7606
550:La Garita
501:27.4? Ma
374:Cochetopa
287:Lake City
230:rhyolites
194:Paleogene
190:Oligocene
183:volcanism
107:Geography
884:See also
826:106°14′W
811:Marshall
783:106°05′W
763:32.2 Ma
740:106°32′W
720:28.7 Ma
697:106°41′W
677:28.4 Ma
654:106°32′W
611:107°32′W
568:106°56′W
521:106°55′W
506:Bachelor
478:106°56′W
458:26.9 Ma
435:107°58′W
418:San Luis
390:106°45′W
345:106°56′W
302:107°23′W
218:Pliocene
159:Tertiary
116:Colorado
112:Location
1324:Bibcode
1010:Bibcode
956:Bibcode
823:38°20′N
780:38°19′N
768:Bonanza
737:38°12′N
694:37°42′N
682:Unknown
651:37°21′N
639:Platoro
608:37°58′N
565:37°46′N
518:37°49′N
475:37°40′N
432:38°01′N
387:38°12′N
342:37°46′N
299:38°02′N
222:Neogene
214:Miocene
123:Geology
1028:
974:
864:quartz
1075:(PDF)
234:crust
202:tuffs
198:lavas
1026:ISSN
972:ISSN
282:Age
271:Name
141:The
1332:doi
1293:doi
1264:hdl
1256:doi
1252:172
1228:doi
1224:108
1197:doi
1116:doi
1087:doi
1053:doi
1018:doi
964:doi
934:958
216:to
1372::
1355:.
1330:.
1320:11
1318:.
1314:.
1289:89
1287:.
1262:.
1250:.
1222:.
1209:^
1195:.
1159:^
1128:^
1112:74
1110:.
1083:46
1081:.
1077:.
1049:96
1047:.
1024:.
1016:.
1006:89
1004:.
984:^
970:.
962:.
952:81
950:.
928:.
913:^
185:.
1357:2
1340:.
1334::
1326::
1299:.
1295::
1272:.
1266::
1258::
1234:.
1230::
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1199::
1153:.
1122:.
1118::
1095:.
1089::
1059:.
1055::
1032:.
1020::
1012::
978:.
966::
958::
862:−
259:.
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