U.S. DEPARTMENT OF THE INTERIOR SCIENTIFIC INVESTIGATIONS MAP 3000 U.S. GEOLOGICAL SURVEY Pamphlet accompanies map

Xgc Kp 54 Qac 60 42 54 Qc Qdf CORRELATION OF MAP UNITS 72 YXgd Ygd Qtb Qg2 35 45 56 75 Qlv Kl Qva 75 60 Qva 53 45 65 63 Qc 38 74 YXgd YXgd Qt 10 Qva 60 50 69 13 Kf Qes Kl Qb Xb Xb Xbc Qt 57 Kp Kp Qv Qva Qac Qtp Qtp Qg1 Qva ၤZk 15 56 Nၡt Xb Qtp Qva XgdB Qds 25 Kp Qc Qrg Qt Qls Qls SURFICIAL DEPOSITS Qls ၡ Qtb 60 Jm 40 Qlv 13 4 Kf Kmu Qg1 Qls 80 60 QNdr Qg2 35 XgdB YXgT Yg 68 40 Qg1 HOOSIER 50 ၣ Kn 15 Kmw 61 Pl Kl 45 Qlo Qva Qti 52 57 Qva Qc Qa Qb Kf 20 Ygd Qc ROGERS ၧ Kb Qdv 42 70 84 P f Kp 16 Artificial Alluvial deposits Alluvial and Mass-movement Mass-movement Glacial Eolian 44 50 53 ၡKpc YXgT 80 XgdB 60 70 ၡ 65 Qt LIVINGST54 Yg Qa Qt YXgd N t 65 Xb 47 37 Yg 88 Qds Qa Qs fill deposits mass-movement deposits and glacial deposits deposits Qg3 60 Qac 54 Qv Kl 12 47 Qls deposits deposits Kmw 84 ၡKdg 60 Qdf 39 85 75 Kl QNr 8 60 Kn 80 Qrg Qva 80 64 20 Qc Qes Ka Kp Kd Qp2 Qls 80 Qti 55 ONE 44 Qf Qg3 Qt 40 53 Qc Qac af 60 YXgT 55 Qlv 13 Qa Holocene 76 Xh XgdB Pl 56 Qrg Qmg 18 18 83 ၡKdg 37 FAU Kph 40 Qc YXgd Qf Xh 53 49 Qdv Qc Qva Qes 7 72 51 Kf Qf 60 Xb Nၡt Qg2 Qc YXgT 80 LT 63 Qes 24 Kb Xh Qtp 13 QNdr Qc Qb Qg1 Qp1 Qac QcQdf Qls Qt 59 Xf 45 10 Qc Qlv Qtp ၡKmu Qc Qtp Xf Qc Qtb 58 Qs 67 Qp1 Qtp Qc Qlo Qc Qtb 57 Qds Kl Kl Qti Qg2 Qc Qti Qt Qb Qs Qva Ng Kf Qlv Qg2 Qp2 Qtb Qls 38 49 Ng FAU Qls Qls Xh Qtb 51 70 Ka Qc ? ? QUATERNARY 25 14 55 Qf Qg1 70 Qv ? ? ? ? ? Pleistocene 24 Qtp XgdB 45 LT 53 af 18 46 Kd 8 Kd Qg3 Qva 43 39 Qb Ka Qs Qg3 Qds 19 Qva QNdi Qmg Xh 51 Ng YXgT FAU 20 44 37 Qt 72 Jmr Qdf Qv Qg1 ၡKpc LT Kb Qa ? Kn Qg1 Xf Qva 57 44 Qdv Qs Qls Qc Qva Ygd 64 HURRICANE HILL 23 45 Qc Qc Qls Qv Qg4 Qdv 30 Qg4 73 53 Xb 46 QNr Qa Qv Kp Qc ၡKpc YXgT 8 Qs Kn Jm 40 34 Qva Qlo ? QNdi Kmw 45 Qva Xf Xbc 55 Qc Xgh 75 62 67 XgdB 49 LARAMIDE AND 20 Kb Qc Xhc 28 Kp 50 Qs QNr QNdr 31 Qt Qtb Qc 55 Qlo POST-LARAMIDE 26 Kd YXgd 77 51 80 77 Xq Qt ? ? Qls Qti Xhc Qls Qg3 50 Qtb Xh Qa Qva Qls Qls Qt Xf FAULT ZONE Qc Qc QNpr SEDIMENTARY AND Pliocene Kb Qg3 64 52 Qls Qc Qlv 28 Xh 67 45 Kl 54 70 XgdB 45 Kf VOLCANIC ROCKS Jm Kd ၡt 56 56 60 Kl Qb ? ? Jm 48 Qtb Qc 70 Qtp 60 40 Qs Neogene Xb Xb 61 QNr 32 OF FRASER BASIN Xb ၡ QNdi 25 Qc 48 Qc N t Qti 54 48 ? 50 Xh Xbc Qf Qva Jm Qdv 58 85 Kb QNdi Qg2 80 YXgT Kph Qb Ng Xhc Qls Qg4 65 Qrg 45 Qf Qls Miocene Kd Qc Xhc 44 42 Qv ၡ Jm Qtp Nၡt 50 59 Ka N t ၡKix 55 Xh 44 Xq Pၧf ? Qtp Qc Qg1 ၡKd 8 42 Qva Qls Xb Qva 45 Xgh QNpr Unconformity 72 Qtp ၡ QNdi Qt Kb QNr Qc Qs Qlv TERTIARY AND CRETACEOUS INTRUSIVE ROCKS 67 t Xb 70 57 XgdB 56 Qt Pl 45 Qc 34 ၡt Xf 35 Qs Ka 60 Qt Qtp Xh XgdB 79 Jmr Oligocene Xh Qtp Ygd 52 YXgT Kd ၡ 30 Qf Qls 74 Ka ၡrp t 40 35 Qf Qc Pl 35 Qc Qv Qs ၡ 82 YXgd Xh Jm 44 Xgh Kd Qtb Qg1 Qtb YXgT 50 15 76 Xq Qls Kd Xhc ၡ Qg1 Qg1 27 42 Qc Qls YXgd 67 t Qva YXgd 50 ၣPl Ka 70 Xh 65 Xf ၡKpc Xb XgdB 29 Kb Kf Kl 36 22 66 Kp Qv ၡma ၡ 42 Qf 27 73 Qc pc TERTIARY Xfh 40 50 24 44 40 Qls Qlo Qc 70 Xhc Qc 50 75 Qva Xqs Qb Eocene 50 Xb Qtb Xbp Qt 56 41 86 YXgd Qc Xbc 48 63 Kn QNpr Qc ၡKi ၡ

FAULT 67 Ka Qv Qa mm Qc 74 30 34 Qls Xgb 38 45 Qc 68 Qc 49 Qa Qc QNr Qt Xbp 46 Ygb YgSP 65 70 44 Qb ၡ 65 45 78 Qa Qlv 48 45 Xh Qva Xh Kpc 40 Kl Paleogene Qtp Qtp Xf 67 23 62 Qc 52 69 YXp Qls Qt YXcr 35 Qs 73 YXgd Qt 80 Xq ၡKd 70 Qls Qls Qva 72 74 55 Qac YXgT Qf QNr Qlv 60 50 Xf Qc 64 Qv Qs LARAMIDE SEDIMENTARY Xh Xhc 50 Qc Qtp 45 50 Qt Xb Qc 35 45 Xhc Qtp Qc 68 Xh Xgh Kl Qls Qlo AND VOLCANIC ROCKS 53 Qc 87 58 46 Xbp 27 Qtp 75 XgdB Qb 55 27 Xh ၡKix Paleocene Xhc Qc YgSP YgSP Xh 37 QNr YXp 45 75 40 77 ၡg 72 67 75 42 Kp Qc ၡKd Xh 43 Xf 65 Qls Qt 80 YXp 40 55 Xc 82 Qtp Qf YgSP Qac Qc Xqs Xlg Qa 60 60 Qt 59 65 QNpr ၡKd 74 60 Qf YgSP 27 Xf Xq ၡ ၡbi YXgd Qva Xq YXcr YXp Kf ၡ Kdg ၡ ၡKpa Qf Xb 72 Qc Qc db Kpc Xb Qrg Qc 45 48 Qes QNr ၡ ၡKmu 85 Xb Xf 36 af Ka Kda Qls Qrg 60 Ygb Qrg 25 YXgd 66 45 77 Qf ? Xc 65 Xf 58 Xbp 68 Kb ? ??? 72 74 80 Xh 77 Qs Qv 80 59 58 Qt 53 Qc 55 73 Pl Qa Ka Kmw Qtp 60 Qt 9 XgdB 80 32 Qb Xb Qf Kl Qs Xhc Xf 30 Xgh ၣ 73 Qtp Xh Pl Qv Unconformity YXgd Qc 72 Xf Qc Unconformity 49 Qva 30 78 Qls 34 30 34 79 51 Ka Kl Qa Qc PRE-LARAMIDE SEDIMENTARY ROCKS YgSP Qtp 30 80 Xb 80 72 ၡKd 45 75 Xlg 77 XgdB 80 51 Jmr Qv Qt 78 45 42 Qls Qlo YXgd 71 60 Qtp XgdB Xf 51 85 Kd Kl Xb APEX ၡKpa ၡ 67 Qmg Qc Qac YXgT 80 bi Qc Xc 66 45 Qva Xlg ၧ Klf 62 68 35 P f ၡKd Qc 65 Qt 28 YgSP 40 72 78 58 Xbp Qb QNr Qrg YXgd 12 25 Xgh 40 75 Kf Upper Xc 54 YgSP 87 Qa Qt 45 Qac 85 Qlv Cretaceous Qls Qrg Xh ၡKpc XgdB 60 Xh 78 74 Xhc Qls Qva 10 68 Xh 65 Qlv Kp CRETACEOUS ၡKda 81 36 Qtb Xf Qac Qlv QNr ၡ Kph Kpf 80 Xhc 72 Kp Ka Kd 65 57 ၡKix 56 75 JUNCT ၡbi Kp YgSP Qrg 22 YXgd Xf Qb Kb Kn Ka Qs Qc 40 Qls Qc Xf Xh Qls 40 Qac 56 Xb Qc ION 60 63 80 ၡ Qtp 35 5 18 Xh Qc Kd Kn YgSP Qc 52 60 75 35 Ka Qrg Qt Xf 65 YXgd Qc 50 18 69 Qa Qes 40 65 57 Xc Qls ၡKda Unconformity Qls 70 Qva Qtp 40 50 45 57 67 Xf Kl YgSP 24 85 Xf Xbc Qf Qti 35 Qt 36 Qa ၡ 20 62 67 48 Qv Kb 41 Xb 74 84 Qt 57 Kpc 54 Qc Qtp YgSP Qt YgSP Qac 55 85 XgdB Qlv ၡKd Lower Qls 57 Qc 40 Xh Qva Qc Qb Qls Xb Qf YgSP XgdB Xbp Qc Kd 68 35 60 YXp Qc Qa Qv Qa Cretaceous Qf Xf – 37 Qva 61 Qti 70 Ygd Xc 58 57 Qc Qrg Xb 36 ၡKpc ၡKd Qf YXgd 45 20 75 ၡdb Qs Qc Qls 67 Xbhc Pl Qs Unconformity 65 78 ၡ Qva 80 Qva 20 Xf Kpa ONER 65 Qes 45 Xf 24 YXgd Xc Kd Qt 25 34 33 BLACKHAWK RANCH 80 Qf 70 Qc Xh Qc ၡKd Jm Jmr JURASSIC Qtp Qva Qf 66 Qf Qac Xh 47 Xhc 80 YgSP Qtb WAG Qc 72 75 Xh Klf Qf Qtb Xh Qva 59 70 ၡ Qtb YgSP af 72 Kpa Qc 69 Xb FLOYD 47 Kp Unconformity Qc 51 ၡ 76 Qb Qa YgSP Qt Kix Xgh Xf 36 Xfh Qlo Qc ? 70 ၡpc Qls Qls Qc ၡKpa Qac 62 66 56 85 Xf Ka Qc ၣ TRIASSIC ၡ 15 49 Xbp Pl Qf Qls 37 Qf pc Qls Qc 65 Qs ၡKd ၡrp Qt Qf 60 Qf 43 Qg1 Xbhc Xhc 60 75 75 Qg1 Qc Xbp 62 Qrg Qc Qtp Qtb 65 ၡ Ng Qva Qf Pl Xf Kpc Qt Qlv ၡdb 58 79 Xfh Qls 60 Xf Xfh PERMIAN af 40 Qt 53 Xb 57 61 39 Ygd 86 ၡKpa 52 Qac Qc Unconformity Xb 59 57 ၡ 48 Qva 63 Xh 45 35 Qls Qls 42 67 Kpa 48 45 40 Qtp 40 Xfh 27 Xgg 55 Qlv Qa Qf WILD Xf Ng 65 Xb ၧ YgSP Xb 72 60 Xb P f ၡKpa Xf 54 QNr PENNSYLVANIAN Xh Qt 43 50 Qb Qls 36 Klf Qv Qtp Qac QNdi Xh 60 Xlg 20 FAULT Qs ၡKd Unconformity Qtp Qf Xfh 40 Qf 50 Qa ၡrp Qt Qtp 60 78 60 Xf Xf Ka Qc Qa Qls YgSP YgSP Qc Qc 74 20 Xgg CAMBRIAN AND PROTEROZOIC INTRUSIVE ROCKS Qls 82 32 45 60 Qv Qc Qg1 YXp Qc Ng Qs Qs Qb Xb Qrg Yd YgSP 69 70 40 Xhc Qva Xbg ၡKd CAMBRIAN Qc Qb ၤZk 45 74 45 YgSP 56 63 25 Xb 60 LATE PROTEROZOIC 32 Xh ၡKd Xh 45 85 Xfh Qb Qa Xh Qc Qls 89 Xfh 47 Pၧf 70 Qf 52 Xh Xlg 50 Xf YgSP Qrg Qt 37 Qac Xgg Qb YgSP 45 Yd 83 FAU 30 Qc Xfh Xf 33 75 35 Qls YgSP 60 LT af Qls YXp 75 YgSP Qc Xlg 70 Xfh Qls Qs QNr Rocks of the Qtp Xb Qg1 74 70 Qac Xf 70 75 Qls Qc 85 Ng Xfh ၡ Qc YgPp 30 Xh Kd ၡKd Pikes Peak Yd Xf 86 Xh Xfh IDAHO 80 Xlg Xf Qlo YgP batholith PROTEROZOIC CATACLASTIC Qt YgdM YXp 70 Xh ၣPl Qb ၡKd Xfh 67 Xf 20 Ka ? AND DUCTILELY 30 70 75 Qc 85 Qs Xlg YXp 37 Xf 79 Xhc Ygi Ypd MIDDLE Xfh Xb Qc 54 85 Qva Kn QNr ၡ Qc DEFORMED ROCKS ၡpc 30 Qv g Qc Qls 74 Qc Xhc PROTEROZOIC Xbc 45 65 76 Qv Qf Qac Xfh Klf QNr Rocks of the 70 Qg1Qf Qti 76 Qtp YgSP 60 YgdM 35 40 YgSP Yg Ygd Ygb 40 Qls Qf ၡ 86 Xb SPRINGS Xfh 70 80 Xf 70 pc Qac Qac Jmr Yd Berthoud Qls 43 Xhc Xc Kb Qtp 62 Qva Xh Plutonic 65 Xb Qrg 65 Qls Qc 50 Kd Qv YgR YgdM ? YXcr 32 50 HILL Xc Qa Qs Suite Qls Qtp Xb 41 YgSP 34 60 Qls 55 Qt Qva Xb Xf 35 Pl ? Qc Qc Xhc Qlo Qf 18 75 85 80 Kp YXgd Qmg 78 Qls 40 Xbc Xh Qls Qv YXp YXgT 75 48 30 Qc Qc Pၧf ၡKd Qva 70 Xgr Qt YgSP 45 80 80 Qv Xgh Qtp YgSP Xf 45 YXp 26 Xc Ka Xgb Qva 50 Xf 64 40 Xbc YXp Qc 55 Qva Qs Rocks of the Qf Xf 40 Qc Qt Qc Xhc 50 Xc Routt Plutonic EARLY PROTEROZOIC Qrg 70 YXgd 20 Qc XgdB 55 26 Xgg 60 Xbc ၡKd Qa Qc Qc Xfh 40 Xgg Qc Qb Suite Qls 70 45 Qva 50 Klf Qlv Xgg METASEDIMENTARY AND Xb Qc 80 Kn ? YgSP Qlv META-IGNEOUS ROCKS Xfh 40 Qva 48 65 Qs 77 Xhc Qs ၡKd Xgg Xf ? ? 35 Qf 61 Qac Xhc 85 YXp Xhc YgSP Qtp Ng Xb 57 65 Qa Xq Xqs Xfh Xlg 80 65 Ka YXp Xb 75 77 40 Xh Xf ၡKd ၡKd Qtp KENNEDY 42 Xb 44 Qs ? ? 46 Qtp Qti YXp Xf Qlv Qv EARLY ၡ 48 Qc 44 65 Yg 45 80 70 Qva pc Qls Qc YgdM 57 Xbc Qls FAU Xhc Kp Qc PROTEROZOIC 40 Qva Qls Qa Qlv Xbp 25 Xh Kph Qv 65 Qtp Qva Qti YgdM LT 62 Qt Xfh Xb 37 12 75 Kb ၡKd 55 Jmr Qt 48 Qva 62 44 Xh Xgb Xbc Xlg Xb Xbhc Xbg YgSP 60 Qt Qf 50 Xf Xbc Pၧf 65 Qc Qt Qt 33 Ng Xgg 50 Qls 48 ၣPl Xb Qt Qc 14 YXp 52 Qa Qc Relative ages 35 Qt Qrg Qrg Xf 24 45 30 45 80 Xbc Xsr Xhq 60 36 27 Xhc 75 Qc Qb Xc Xh Qls 42 70 Qs 50 not implied Qc 32 52 YXgd Ka 71 70 Qf 32 51 25 Qa Qc 40 Qmg 62 Xgr Ng 70 FAU Xh Qt 38 Qls 71 YXp Pl 37 Qv Xaq Xf Xfh Xh Qls Qc Xfh 60 50 GULCH 40 Xb Xhc 50 Qls 30 28 LT Xsr ၡmm Qva Xb 70 Qt Qc 76 Xgh Qac YgSP 35 Xb YgR Xb Ng Qva Qs Qc Xgg 75 Qs Qlo Xhc Xgc 37 Qt Qt YgdM 40 Qv Qtp 30 75 ၡKda Kp Xh 32 35 Qac 70 Qva 55 Qc ၡma 35 Kd Qf YXp Qtp Qc 75 Qes Kpf Qls 50 18 Qg1 Qtp Qrg 55 Xf Qdf Qac Xaq Kl Qf Qb Qls 80 Qc Qv Qf 60 70 Qc Qtp Qls Qt Qva FAU Qva Xbg 28 Qva Qt 80 Qt 80 Kn ၡ 40 Qls Qac Qt Qc 10 Kf Qs Kd ၡ 50 LT 35 Kpf mm ၡma Qrg Xgg Qac Qa Qs Qtb 24 Xf 80 Qva YgdM Qac Qa Qls YgSP Qc Qls Qtp 60 YXp Qc 48 ၡmm Qc Qt 60 50 Kb Kp Kb Yg 80 55 70 Qf Qs 80 30 Xfh 80 Xh Qac Yg 60 Qac Qrg Qt Xb Qs 38 Xb YgdM Yg 85 Kph ၡKd Rocks of Montezuma stock and vicinity (Eocene) Xgh Mafic granodiorite, quartz diorite, hornblende diorite, and hornblendite 50 Qls YgdM 35 45 50 LIST OF MAP UNITS 38 Qc Xf Kn 36 65 Qt 30 30 60 Pၧf Qb Qb Qlo (Early Proterozoic) Qc 50 ၡma Aplite Xfh 77 Qc Yg 40 Xgr Qv Kf SURFICIAL DEPOSITS 35 80 40 46 Qrg Qls 35 60 Qls Pl 72 Xgb Gabbro (Early Proterozoic) 56 Yg Qva Artificial fill deposits ၡ Qt Yg ၡ Yg Qc 25 ၡKda mm Monzogranite porphyry 50 Xh rp 26 Xaq 55 40 21 YXp YgR Qrg Qc Qc 75 Qac Qv Kp 25 Qac Xb 80 Qlo af Artificial fill deposits (latest Holocene) XgdB Boulder Creek Granodiorite (Early Proterozoic) 44 53 Qls Xb ၡpc Younger felsic to intermediate porphyries of alkali-calcic group (Eocene) 16 Qt Qac 40 ၣ Qv Xfh Xf ZONE 36 Qva 85 Xhq Qc Qs YXp Qc Xb Pl 55 Qes Alluvial deposits Xgg Granitic gneiss (Early Proterozoic) 45 70 Qtp Xb 60 Qls 40 Qtp Qls Qt Xfh 60 Xhq Xq Xq Jmr ၡKd ၡKix Intrusive breccia (Eocene to Late Cretaceous?) 14 21 Xfh Qa Qc Qa Post-Piney Creek alluvium and Piney Creek Alluvium, undivided (Holocene) Qls Qf Kd PROTEROZOIC CATACLASTIC AND Qac Qac Qs ၡKdg Xh 60 Xf Xgg Qtp Xb 35 Qa Diorite, gabbro, and lamprophyre (Tertiary and Cretaceous?) Qls 60 60 YgR Qt 75 ၡKda Qva Valley-floor alluvium (Holocene and late Pleistocene) DUCTILEY DEFORMED ROCKS Xf Qc Yg Qc YgdM 55 30 ၡ 14 Qc Qac Qc Kf Kpc Qac YXp 45 Qtb 45 Older felsic to intermediate porphyries of alkali-calcic group (Paleocene to YXcr Cataclastically and ductilely sheared rocks of the Idaho Springs–Ralston 42 40 Qtp 50 55 YgdM YgdM 50 Xgh Kl Qb Broadway Alluvium (late Pleistocene) 50 Xh Yg 15 YXgd Qa Late Cretaceous?) shear zone (Middle and Early Proterozoic) Xfh 54 Xf Qc YgPp Kn Qls Xb Qva 80 Kp Qes 46 51 Qc ၡKpa 85 Qva Qac 76 Qg1 Young stream-terrace alluvium (late Pleistocene) Porphyries of the alkalic group (Paleocene and Late Cretaceous?) Kd 40 Xb 71 75 ၡ Qti 85 EARLY PROTEROZOIC METASEDIMENTARY AND ၡ 30 Kp mm Xb 85 pc Kb Kn Xfh 70 Qc Qf 86 62 Qs Qlv Louviers Alluvium (late and middle Pleistocene) ၡbi Potassic basalt (shoshonite) intrusive of Ralston Buttes (Paleocene) META-IGNEOUS ROCKS Xh 80 Qc Qs Qb ၡpc 30 60 Qc YgP 65 75 Qc 60 Pၧf Kb Qb Xq Quartzite (Early Proterozoic?) 49 Qls Qtp Xgg 75 Qg2 Intermediate stream-terrace alluvium (late and middle Pleistocene) LARAMIDE SEDIMENTARY AND VOLCANIC ROCKS Qc 27 60 Xf YgP 40 65 Pl Qa 78 Qrg Xf Yg 80 Qa Qs 54 80 60 Qg1 Qc 25 Xf Qls Qv OF THE DENVER BASIN Xqs Muscovite-quartz schist (Early Proterozoic?) Qtp 50 Qac YgPp 55 Xaq Qs Slocum Alluvium (middle Pleistocene) 14 Kn Qg1 Xh 65 ၡ 8 35 Qrg 50 Xgg Qva g Green Mountain Conglomerate (Paleocene) 50 50 YXgd Xbp Porphyroblastic quartz-biotite-muscovite schist of White Ranch (Early Qls Xfh 45 70 Ng Qg3 Old stream-terrace alluvium (middle and early? Pleistocene) 75 55 Qv Qb ၡ Xf 60 Xf 80 Xgg Xb Kda ၡ Proterozoic) Kd Kb 50 YgP 80 Xaq QNr Kd Denver Formation (Paleocene and Upper Cretaceous) ၡ Qf Qb Qc 60 45 Qc Xgg Kd pc 26 Qt 50 Qls Qti Qf 60 Qv Verdos Alluvium (middle Pleistocene) Xlg Mixed layered gneiss (Early Proterozoic) Qva Xgg 62 Qv ၡdb Potassic basalt (shoshonite) lava flows (Paleocene) Kp ၡmm 55 Qc Xb Xb 55 Qes 32 Xb Qc Qg4 Oldest stream-terrace alluvium (middle or early Pleistocene) 50 75 Xf Qac Xf Xhq Xb Xb Biotite gneiss (Early Proterozoic) Qf 55 Qtp Xh 75 Xb 70 Qs Qc Qva 35 Qva Ka Arapahoe Formation (Upper Cretaceous) Qc 40 Xh ၡmm Yg Yg 50 61 Qlo Xfh QNr Rocky Flats Alluvium (early Pleistocene and late Pliocene?) Xbhc Biotite gneiss, hornblende gneiss, and calc-silicate gneiss (Early ၡ Denver Formation (Paleocene and Upper Cretaceous) and Arapahoe Kda Proterozoic) QNpr Pre-Rocky Flats alluvium or debris-flow deposits (early Pleistocene or late Formation (Upper Cretaceous), undivided Base from U.S. Geological Survey, 1983 12° SCALE 1:100 000 See "Index to Sources of Geologic Data" Pliocene) Xbg Biotite gneiss and schist with garnet (Early Proterozoic) Projection and 10,000-meter grid, zone 13 1 0 1 2 345 678 MILES Digital base map prepared by Theodore R. Brandt PRE-LARAMIDE SEDIMENTARY ROCKS OF THE DENVER BASIN, Alluvial and mass-movement deposits Universal Transverse Mercator RTH COLORADO Manuscript approved for publication April 11, 2008 BLUE RIVER VALLEY, AND FRASER BASIN Xc Calc-silicate gneiss (Early Proterozoic) 25,000-foot grid ticks based on Colorado coordinate 1 012 354 6 789 10 KILOMETERS Qac Alluvium and colluvium, undivided (Holocene to middle? Pleistocene) Kl Laramie Formation (Upper Cretaceous) Xbc Cordierite-biotite gneiss (Early Proterozoic)

system, central and north zones TRUE NORTH Qf MAGNETIC NO CONTOUR INTERVAL 50 METERS Fan deposits (Holocene and late Pleistocene) 1927 North American Datum QUADRANGLE LOCATION Kf Fox Hills Sandstone (Upper Cretaceous) Xsr APPROXIMATE MEAN Rutile-sillimanite-quartz gneiss (Early Proterozoic) DECLINATION, 1983 NATIONAL GEODETIC VERTICAL DATUM OF 1929 Qp1 Lower pediment deposits (late Pleistocene) Klf Laramie Formation (Upper Cretaceous) and Fox Hills Sandstone (Upper Xhq Amphibolite, marble, and quartzite (Early Proterozoic) Qp2 Higher pediment deposits (late and middle Pleistocene) Cretaceous), undivided Kp Pierre Shale (Upper Cretaceous) Xaq Amphibolite and quartzite (Early Proterozoic) Qds Debris-flow deposits and Slocum Alluvium, undivided (middle Pleistocene) Kpf Hornfels Xf Quartz-feldspar gneiss (Early Proterozoic) QNdi Diamicton (middle? Pleistocene to Pliocene?) 106°00' 106°00' ° 105°00 105°00' 105°00' 106 00' Xfh Quartz-feldspar gneiss and hornblende gneiss (Early Proterozoic) 40°00' 40°00' 40°00' Kph Hygiene Sandstone Member Caribou BOULDER CREEKHoosier fa Qdv Debris-flow deposits and Verdos Alluvium, undivided (middle Pleistocene) Livingston fau stock B. Bryant R. Shroba Xh Hornblende-plagioclase gneiss and amphibolite (Early Proterozoic) Boulder EXPLANATION Taylor Young Gable Wells Kn Niobrara Formation (Upper Cretaceous) Tabernash Lafayette Rogers fau (unpub. mapping, (unpub. mapping, QNdr Debris-flow deposits and Rocky Flats Alluvium, undivided (early FRASER ult (1975) (1991) (1969) (1967) 1969); 2005) Pleistocene and late Pliocene?) Xhc Hornblende gneiss and calc-silicate gneiss (Early Proterozoic) Fraser Bo k Louisville Troublesome Formation (Fraser Basin) Kb Benton Group (Upper and Lower Cretaceous) ulder Cree Nederland k BASIN R. Shroba Sout ree Hurr B. Bryant F h Bo C lt zone lt Boulder-Weld (Miocene and Oligocene) Gable Machette Ng High-level gravel deposits (Miocene?) r ul r (unpub. mapping, R. Shroba R. Shroba Malde (1955); Xgc Mixed calc-silicate and biotite gneiss (Early Proterozoic) a d e Superior Eldora icane Hil (unpub. mapping, Kd Dakota Group (Lower Cretaceous) s Intrusive rocks (Oligocene to Late Cretaceous) R. Shroba 2005) (unpub. mapping, (1972) (unpub. mapping, Spencer (1961) (1977) k e k stock 1969); Mass-movement deposits e Winter r ee 36 (unpub. mapping, e r fault zone 2005) 2005) R eek C l R. Shroba r der Cr k fault 2005) Jm Morrison Formation (Upper Jurassic) C Park i th Boul oc Sedimentary and minor volcanic rocks of Qc Colluvium (Holocene to middle? Pleistocene) v k P. Theobald e ou R BATHO (unpub. mapping, Shroba and e Broomfield r S zone Denver Basin and Middle Park Contact—Dotted where concealed k e (unpub. mapping, 2005) Carrara (1996) s r Apex Jmr Morrison Formation (Upper Jurassic) and Ralston Creek Formation i e Co (Paleocene to Pennsylvanian) Louisville Lafayette Qdf e a C Eldorado Springs Debris-flow deposits (Holocene to middle? Pleistocene) u l stock Bottle Pass 1967) Fraser East Portal Nederland Tungsten r LITH (Upper and Middle Jurassic), undivided o Standley Fault, type unspecified—Dotted where concealed C E L 93 shear zone zone Pikes Peak Granite (Middle Proterozoic; ca. z 119 R. Shroba t Lake s Lake Qls Landslide deposits (Holocene to middle? Pleistocene) ၣ e 40 Creek Pl Pl Lykins Formation (Triassic? and Permian) S ton 1,080 Ma) (unpub. mapping, u Rals Thrust or reverse fault—Dotted where concealed q Theobald Braddock 2005) s Saint Loui N fault Rocks of the Berthoud Plutonic Suite (Middle Sims (1964); Qt a o Talus deposits (Holocene to middle? Pleistocene) Pl rth LUME shear (1965) (1969) Pl Lyons Sandstone (Lower Permian) V DIVID DENVER Proterozoic; ca. 1,400–1,450 Ma) Sims and Taylor Sheridan and Van Horn Lindvall Anticline in Phanerozoic rocks F Black Gable (1967) Mass-movement and glacial deposits all G SILVER P Fall fault Junction (1976) others (1967) (1976) (1979) Pၧf Pf Fountain Formation (Lower Permian and Pennsylvanian) R u k Dory Hill Rocks of the Routt Plutonic Suite (Early R. Shroba R. Shroba ive Hawk y Van Bibber Creek ee River BASIN Overturned anticline in Phanerozoic rocks r C G Cr (unpub. mapping, (unpub. mapping, Qrg Rock-glacier deposits (Holocene and latest Pleistocene) le Proterozoic; ca. 1,700–1,760 Ma) a u stock Eppinger R. Shroba k Central r lc ar Ralston 2005) 2005) CAMBRIAN AND PROTEROZOIC INTRUSIVE ROCKS W s F or h le and others ill am C C Ranch Meta-igneous and metasedimentary rocks (unpub. Syncline in Phanerozoic rocks—Dotted where concealed i r 70 70 Qmg Mass-movement and glacial deposits, undivided (Holocene and latest City e ITH Empire Golden e (1984) ၤZk Kimberlite (Cambrian or Late Proterozoic) k stock Blackhaw (Early Proterozoic; ca. 1,730–1,760 Ma) mapping, Central West Idaho Berthoud 70 Pleistocene) Overturned syncline in Phanerozoic rocks Fork Golden BATHOL Byers Peak Berthoud Pass Empire 2005) City Black Hawk Ralston Buttes Golden Arvada Springs – fault Contact YgP Pikes Peak Granite (Middle Proterozoic) Clear Creek Lincoln k fault Glacial deposits 70 6 – Mtn Anticline in Proterozoic rocks—Dotted where concealed 25 Springs Floyd Fault stock Qtp Till of Pinedale age (late Pleistocene) YgPp Fine-grained porphyritic phase rook 6 Silver B Mt V Idaho S B. Bryant Overturned anticline in Proterozoic rocks Georgetown ek Beaver ernon Thrust or reverse fault—Sawteeth on upthrown Ygi Clear Plume re Cany Greater Idaho (unpub. mapping, Qtb Till of Bull Lake age (late and middle Pleistocene) Gabbro dike (“Iron dike”) (Middle Proterozoic) C C on fault r eek o side 1969); Widmann and Widmann and Sheridan and Sheridan and Scott Lindvall g Denver Loveland Pass Syncline in Proterozoic rocks—Dotted where concealed CONTINENTAL a Miersemann (2001) others (2000) Marsh (1976) others (1972) (1972) (1978) Ypd c Creek prings R. Shroba i Bergen Folds in Phanerozoic rocks—Showing direction Qti Till of Pinedale age and till of Bull Lake age, undivided (late and middle Pyroxene diorite dike (Middle? Proterozoic) h (unpub. mapping,

C of plunge Overturned syncline in Proterozoic rocks Park Bear Cree Bear Creek Lake Bear Pleistocene) Van k Cr fault 2005) YXp Pegmatite and aplite (Middle and Early Proterozoic) ce eek Hill Anticline Cre Straight (patterned area) Eolian deposits Strike and dip of bedding ek 74 fault zone Kenn Morrison edy YXgd Granodiorite and monzogranite of unknown age (Middle or Early 6 Syncline Loveland Pass Idaho Springs Squaw Pass Evergreen Morrison Fort Logan Qes Eolian sand (Holocene and late Pleistocene) 51 ek Grays Peak Georgetown Inclined Cre Gulch Proterozoic) ke reek Evergreen Folds in Proterozoic rocks—Showing direction na Rive C Marston fault Robinson and Qlo S r ar Loess (late and middle? Pleistocene) YgSP Silver Plume Granite (Middle Proterozoic) Vertical e Lake Montezuma MOUNT EVANS– fault of plunge B y Frey others (1974) B. Bryant rke stock 73 Tu Gulch YANKEE CREEK Anticline (unpub. mapping, LARAMIDE AND POST-LARAMIDE SEDIMENTARY AND Yg Peraluminous monzogranite (Middle Proterozoic) shear Ulrich Overturned 470 zone 1969); Bryant Bryant and Scott zone PLUTONS (1963) VOLCANIC ROCKS OF FRASER BASIN G 285 Overturned anticline R. Shroba e Aspen (1974) others (1973) (1962) Ygd Granodiorite and monzogranite (Middle Proterozoic) n ၡ Strike and dip of foliation e ek Chatfield (unpub. mapping, N t Troublesome Formation (Miocene and Oligocene) v Park k Cre Modified from a e eer Lake Syncline 2005) 70 re D Widmann and Ygb Younger gabbro (Middle Proterozoic) Inclined C S C ၡt Turk Williams zone (patterned area) Rhyolite tuff (Oligocene) r ey others (2003) e Phillipsburg Overturned syncline e Harris Range Montezuma shear PIKES PEAK Yd Younger diorite and hornblendite (Middle Proterozoic?) k Conifer Indian Hills Littleton Middle Park Formation (Paleocene and Upper Cretaceous) Vertical or near vertical Park thrust Keystone Montezuma Mount Evans Harris Park Meridian Hill Conifer ° ° BATHOLITH Shear zone 39 30' 39 30' 39°30' ၡKmu Upper member (Paleocene and Upper Cretaceous?) YgR Granite of Rosalie Peak (Middle Proterozoic) Braided pattern on the Rocky Flats surface 0510 Miles 0510 Miles INDEX TO SOURCES OF GEOLOGIC DATA Kmw Windy Gap Volcanic Member (Upper Cretaceous) YgdM Granodiorite of Mount Evans batholith (Middle Proterozoic) [Note: R. Shroba mapped or reinterpreted surficial units, as indicated] Breccia zone TERTIARY AND CRETACEOUS INTRUSIVE ROCKS YXgT Twin Spruce Monzogranite (Middle? and Early Proterozoic) Complex intrusive network of Middle Proterozoic monzogranite (units 05 20 Kilometers 05 20 Kilometers ၡKi YgSP or Yg) Intrusive rock, undifferentiated (Oligocene to Late Cretaceous) Xgr Monzogranite of Elephant Butte (Early Proterozoic) Proterozoic shear zone INDEX TO GEOLOGIC STRUCTURES ၡrp Rhyolite porphyry (Oligocene and Eocene)

GEOLOGIC MAP OF THE DENVER WEST 30' x 60' QUADRANGLE, NORTH-CENTRAL COLORADO Any use of trade names is for descriptive purposes only and does not imply endorsement by the U.S. Government By For sale by U.S. Geological Survey Information Services Box 25286, Federal Center, Denver, CO 80225 Karl S. Kellogg, Ralph R. Shroba, Bruce Bryant, and Wayne R. Premo 1-888-ASK-USGS ArcInfo coverages and a PDF for this map are available at Printed on recycled paper 2008 http://pubs.usgs.gov