Gregory N. Green 1992 version 1.0 map U.S. Geological Survey Open-File Report 92-507 Denver U.S. Geological Survey http://pubs.usgs.gov/of/1992/ofr-92-0507/ This geologic map was prepared as a part of a study of digital methods and techniques as applied to complex geologic maps. The geologic map was digitized from the original scribe sheets used to prepare the published Geologic Map of Colorado (Tweto 1979). Consequently the digital version is at 1:500,000 scale using the Lambert Conformal Conic map projection parameters of the state base map. Stable base contact prints of the scribe sheets were scanned on a Tektronix 4991 digital scanner. The scanner automatically converts the scanned image to an ASCII vector format. These vectors were transferred to a VAX minicomputer, where they were then loaded into ARC/INFO. Each vector and polygon was given attributes derived from the original 1979 geologic map. This dataset was developed to provide geologic map GIS database of Colorado for use in future spatial analysis by a variety of users. This database is not meant to be used or displayed at any scale other than 1:500,000. This data base consists of three major Arc/Info GIS datasets: - one the geologic map with faults, formations and volcanic vents, - two the index and correlation chart and - three the sources of geologic data. April 1995, An update was done solely for the purpose of adding the abilitly to plot to an HP650c plotter. Two new ARC/INFO plot AMLs along with a lineset and shadeset for the HP650C design jet printer have been included. These new files are COLORADO.650, INDEX.650, TWETOLIN.E00 and TWETOSHD.E00. These files were created on a UNIX platform with ARC/INFO 6.1.2. Updated versions of INDEX.E00, CONTACT.E00, LINE.E00, DECO.E00 and BORDER.E00 files that included the newly defined HP650c items are also included. 1992 publication date Complete As needed -109.1 -102.0 41.0 37.0 none geology none USA Colorado National Geologic Map Database Catalog themes, augmented 3100 - Vector 3110 - ESRI 3112 - export 1100 - Geology 1101 - General Augmented FIPS 10-4 and FIPS 6-4, version 1.0 US08 = Colorado none This database is not meant to be used or displayed at any scale other than 1:500,000. Any hardcopies utilizing these data sets shall clearly indicate their source. If the licensee has modified the data in any way they are obligated to describe the types of modifications they have performed on the hardcopy map. Licensee specifically agrees not to misrepresent these data sets, nor to imply that changes they made were approved by the U.S. Geological Survey. Gregory N. Green U.S. Geological Survey geologist mailing and physical address

MS 905, USGS, Denver Federal Center

Denver CO 80225 USA (303) 236-5390 ggreen@usgs.gov The author wishes to thank Richard Taylor for storing and protecting the original Geologic Map of Colorado scribe sheets and negatives, Margaret Clemensen for assistance in preparing the explanation sheet and Scott Hogan and Kirsten Findell for review of the digital map; all are with the USGS. The author wishes to thank Randy Phillips of the Colorado State Geologic Survey for creating the TWETO.SHD shadeset. VAX/VMS 5.4 ARC/INFO version 5.0 Compiled mapping field checked Manual check against orginals Compiled from 1:250,000 scale maps Ogden Tweto 1979 map Special Publication The Geologic Map of Colorado Reston, Virginia U.S.Geological Survey 500000 map 1979 publication date Tweto(1979) Ogden Tweto created the state geologic map from new and existing geologic mapping. Greg Green converted this to ARC/INFO in 1992. This geologic map was prepared as part of a study of digital methods and techniques as applied to complex geologic maps. The geologic map was digitized from the original scribe sheets used to prepare the original paper Geologic Map of Colorado. Stable base contact prints of the scribe sheets were scanned on a Tektronix 4991 digital scanner. The scanner automatically converts the scanned image to an ASCII vector format. These vectors were transferred to a VAX minicomputer, where they were then loaded into ARC/INFO. Each vector and polygon was given attributes derived from the original 1979 geologic map. Both paper and digital versions are at 1:500,000 scale using the Lambert Conformal Conic map projection parameters of the State topographic base map. 1991 - 1992 Vector Lambert Conformal Conic 33 45 -105.5 0 0.00000 0.00000 coordinate pair 1.0 1.0 Meters North American Datum of 1927 Clarke 1866 6378206.4 294.98 >CODING SCHEME FOR ATTRIBUTES: > >NAME: FEATURE: >P1,P2 Shorthand attributes >BW Line pattern from CARTO.LIN >CCA Line pattern or shade color from CCA.LIN or CCA.SHD >CCB Shade color from CCB.SHD >PATT Shade pattern from DOT.SHD >HP Line pattern or shade color from TWETO.LIN or TWETO.SHD > >CONTACT.AAT >NAME P1 P2 BW CCA HP MAJOR1 MINOR1 MAJOR2 MINOR2 > >CONTACT 1 - 0 1 101 500 201 - - >WATER, SHORELINE 2 - 0 1 101 40 200 - - >STATE OUTLINE 3 - 127 0 139 91 8 - - >FAULT - 1 0 4 102 - - 501 203 >FAULT, THRUST - 2 0 4 102 - - 501 204 >FAULT, DOTTED - 3 106 0 110 - - 501 205 >FAULT, DASHED - 4 114 0 114 - - 501 206 >BAR - 5 0 0 101 - - 501 218 >DIATREME - 8 0 0 101 - - 501 215 >VOL. CONE - 9 0 212 201 - - 501 216 >PC SHEAR ZONE - 22 0 0 101 - - 501 213 >SINGLE LINE OUTCROP - 24 0 0 0 - - 501 226 >NON-PRINTING CONTACT - 25 0 0 0 500 202 - - >Some vectors can have both a P1 and P2 code. Such as a fault that >is also a contact. > > >DECO.AAT >NAME P1 BW CCA HP MAJOR1 MINOR1 > >BALL 6 0 1 101 501 219 >TEETH 7 0 1 101 501 220 >DIATREME 8 0 2 101 501 215 >VOL. NECK 10 0 212 201 501 217 >MONOCLINE 11 0 212 201 501 207 >MONOCLINE, DOTTED 12 0 353 209 501 208 >SYNCLINE 13 0 212 201 501 209 >SYNCLINE, DOTTED 14 0 353 209 501 210 >ANTICLINE 15 0 212 201 501 211 >ANTICLINE, DOTTED 16 0 353 209 501 212 >MONOCLINE ARROW 17 0 212 201 501 221 >SYNCLINE ARROW 18 0 212 201 501 222 >ANTICLINE ARROW 19 0 212 201 501 223 >FOLD ARROWHEAD 20 0 212 201 501 224 >OVERTURNED SYMBOL 21 0 212 201 501 225 >PC SHEAR ZONE 22 0 1 101 501 213 >JURASSIC LIMIT 23 118 0 113 501 214 > > >LINE.AAT >NAME P1 BW CCA HP MAJOR1 MINOR1 > >Tbbi, 49 0 384 501 510 49 >Tbr, 50 0 386 502 510 50 >Tui, 58 0 512 503 510 58 >Tmi, 59 0 505 508 510 59 >TKi, 66 0 441 504 510 66 >Kmj, 99 0 335 507 510 99 >_am, 172 0 331 505 510 172 >Yam, 181 0 449 506 510 181 >Tmi,inferred 185 0 500 509 510 185 > > >CONTACT.PAT >NAME P1 CCA HP CCB PATT MAJOR1 MINOR1 > >Qa, 1 16 1 0 0 520 1 >Qg, 2 24 2 0 0 520 2 >Qgo, 3 31 3 0 0 520 3 >Qe, 4 19 4 0 0 520 4 >Qeo, 5 19 5 0 55 520 5 >Qd, 6 25 6 0 0 520 6 >Qdo, 7 25 7 0 55 520 7 >Ql, 8 25 8 0 71 520 8 >Qb, 9 61 9 0 0 520 9 >QTsa, 10 19 10 0 71 520 10 >QTa, 11 31 11 0 55 520 11 >To, 12 50 12 0 0 520 12 >Tgv, 13 50 13 0 71 520 13 >Ta, 14 50 14 0 55 520 14 >Twr, 15 64 15 0 0 520 15 >Th, 16 75 16 0 71 520 16 >Tcu, 17 47 17 0 0 520 17 >Tpc, 18 303 18 0 0 520 18 >Tdu, 19 303 19 0 0 520 19 >Tbp, 20 50 20 0 0 520 20 >Tt, 21 50 21 0 0 520 21 >Tnp, 22 50 22 0 0 520 22 >Tos, 23 64 23 0 0 520 23 >Tu, 25 75 25 0 71 520 25 >Tb, 26 75 26 0 71 520 26 >Tg, 27 81 27 0 7 520 27 >Tgp, 28 103 28 0 0 520 28 >Tgl, 29 81 29 0 0 520 29 >Tglm, 30 103 30 0 0 520 30 >Tgt, 31 88 31 0 103 520 31 >Tglu, 32 81 32 0 0 520 32 >Tglw, 33 81 33 0 71 520 33 >Tw, 34 47 34 0 0 520 34 >Twc, 35 45 35 0 0 520 35 >Twn, 36 46 36 0 0 520 36 >Two, 37 47 37 0 71 520 37 >Tf, 38 303 38 0 0 520 38 >Tc, 39 303 39 0 0 520 39 >Tm, 40 303 40 0 0 520 40 >Td, 41 50 41 0 0 520 41 >Ts, 42 50 42 0 0 520 42 >Tsp, 43 303 43 0 0 520 43 >Tlp, 44 50 44 0 0 520 44 >Tsj, 45 47 45 0 0 520 45 >Te, 46 47 46 0 0 520 46 >Tn, 47 303 47 0 0 520 47 >Tbb, 48 118 48 0 7 520 48 >Tbbi, 49 152 49 0 0 520 49 >Tbr, 50 186 50 0 0 520 50 >Tbrt, 51 96 51 0 0 520 51 >Taf, 52 152 52 0 0 520 52 >Tial, 53 64 53 0 0 520 53 >Tiql, 54 64 54 0 127 520 54 >Tpl, 55 348 55 0 0 520 55 >Twm, 56 155 56 0 0 520 56 >Tv, 57 79 57 0 0 520 57 >Tui, 58 358 58 0 0 520 58 >Tmi, 59 124 59 0 0 520 59 >TKda, 60 35 60 0 0 520 60 >Tdv, 61 35 61 0 71 520 61 >TKdl, 62 35 62 0 0 520 62 >TKr, 63 35 63 0 0 520 63 >TKa, 64 35 64 0 0 520 64 >TKec, 65 32 65 0 103 520 65 >TKi, 66 387 66 0 0 520 66 >Kl, 67 723 67 0 0 520 67 >Kf, 68 718 68 0 0 520 68 >Klf, 69 718 69 0 7 520 69 >Kvt, 70 723 70 0 7 520 70 >Kp, 71 716 71 0 0 520 71 >Kpu, 72 712 72 0 0 520 72 >Kpm, 73 767 73 0 0 520 73 >Kpl, 74 720 74 0 0 520 74 >Kn, 75 761 75 0 0 520 75 >Kcg, 76 736 76 0 0 520 76 >Kc, 77 761 77 0 0 520 77 >Kpg, 78 709 78 0 71 520 78 >Kdp, 79 785 79 0 0 520 79 >Kd, 80 785 80 0 0 520 80 >Kmw, 81 723 81 0 0 520 81 >Kls, 82 712 82 0 0 520 82 >Kmv, 83 717 83 0 0 520 83 >Kmvu, 84 737 84 0 0 520 84 >Kmvl, 85 751 85 0 95 520 85 >Kw, 86 767 86 0 0 520 86 >Ki, 87 751 87 0 95 520 87 >Kh, 88 737 88 0 0 520 88 >Ksc, 89 767 89 0 55 520 89 >Kmgs, 90 751 90 0 95 520 90 >Km, 91 736 91 0 0 520 91 >Kmfm, 92 709 92 0 103 520 92 >Kfd, 93 785 93 0 95 520 93 >Kdb, 94 785 94 0 0 520 94 >Kkf, 95 723 95 0 0 520 95 >Kpcl, 96 767 96 0 0 520 96 >Kch, 97 720 97 0 0 520 97 >Kmp, 98 761 98 0 0 520 98 >Kmj, 99 736 99 0 71 520 99 >KJdm, 100 755 100 0 103 520 100 >KJdj, 101 755 101 0 103 520 101 >KJdw, 102 755 102 0 103 520 102 >KJdr, 103 755 103 0 103 520 103 >KJde, 104 755 104 0 103 520 104 >KJds, 105 755 105 0 103 520 105 >Jm, 106 746 106 0 0 520 106 >Jmj, 107 746 107 0 0 520 107 >Jmc, 108 746 108 0 0 520 108 >Jmw, 109 746 109 0 0 520 109 >Jmr, 110 746 110 0 0 520 110 >Jme, 111 746 111 0 0 520 111 >Jms, 112 746 112 0 0 520 112 >Jmse, 113 746 113 0 0 520 113 >Jmce, 114 746 114 0 0 520 114 >Jmre, 115 746 115 0 0 520 115 >Jmwe, 116 746 116 0 0 520 116 >J@g, 117 782 117 0 0 520 117 >J@gc, 118 782 118 0 71 520 118 >J@mg, 119 782 119 0 95 520 119 >J@mc, 120 800 120 0 0 520 120 >@kc, 121 790 121 0 0 520 121 >@wc, 122 790 122 0 0 520 122 >@m, 123 741 123 0 0 520 123 >@ch, 124 741 124 0 0 520 124 >@cc, 125 776 125 0 103 520 125 >@c, 126 776 126 0 0 520 126 >@d, 127 776 127 0 0 520 127 >@dg, 128 776 128 0 0 520 128 >@Pl, 129 788 129 0 103 520 129 >@Ps, 130 788 130 0 0 520 130 >@Pll, 131 788 131 0 0 520 131 >@Pjs, 132 788 132 0 95 520 132 >@Pcs, 133 788 133 0 95 520 133 >@Pcp, 134 788 134 0 95 520 134 >@Pr, 135 788 135 0 71 520 135 >@Pdc, 136 788 136 0 71 520 136 >@Pmc, 137 788 137 0 0 520 137 >@&lf, 138 805 138 0 0 520 138 >Pp, 139 682 139 0 0 520 139 >Pu, 140 682 140 0 0 520 140 >Pc, 141 681 141 0 0 520 141 >Mz, 142 0 142 0 71 520 142 >MzPz, 143 0 143 0 71 520 143 >P&f, 144 408 144 0 95 520 144 >P&cf, 145 408 145 0 0 520 145 >P&if, 146 408 146 0 0 520 146 >P&s, 147 408 147 0 0 520 147 >P&m, 148 408 148 0 0 520 148 >P&w, 149 440 149 0 95 520 149 >P&wm, 150 440 150 0 95 520 150 >&m, 151 0 151 14 0 520 151 >&b, 152 0 152 0 103 520 152 >&mb, 153 0 153 14 0 520 153 >&e, 154 0 154 12 95 520 154 >&ee, 155 0 155 12 0 520 155 >&mbe, 156 0 156 12 0 520 156 >&h, 157 0 157 16 0 520 157 >&rh, 158 0 158 15 0 520 158 >&mr, 159 0 159 15 0 520 159 >M_, 160 378 160 0 0 520 160 >MDO, 161 448 161 0 0 520 161 >DO_, 162 448 162 0 0 520 162 >O_, 163 352 163 0 0 520 163 >Or, 164 352 164 0 0 520 164 >MD, 165 448 165 0 0 520 165 >MD_, 166 435 166 0 0 520 166 >DO, 167 448 167 0 0 520 167 >_s, 168 171 168 0 0 520 168 >Mm, 169 448 169 0 0 520 169 >_l, 170 171 170 0 0 520 170 >M_ml, 171 378 171 0 0 520 171 >_am, 172 814 172 0 0 520 172 >Yu, 173 32 173 0 135 520 173 >YXu, 174 32 174 0 119 520 174 >Xb, 175 0 175 18 0 520 175 >Xfh, 176 44 176 0 7 520 176 >Xq, 177 0 177 18 71 520 177 >Wr, 178 319 178 0 0 520 178 >Yp, 179 107 179 0 7 520 179 >Yg, 180 169 180 0 7 520 180 >Yam, 181 689 181 0 0 520 181 >Xg, 182 91 182 0 71 520 182 >Xm, 183 385 183 0 0 520 183 >YXg, 184 348 184 0 71 520 184 >H2O, 200 680 200 0 0 40 100 > >DECO.PAT >NAME P1 CCA HP CCB PATT MAJOR1 MINOR1 > >Pipe, 186 0 0 0 0 530 186 > , (BLANK) 187 0 0 0 0 530 187 >Ball, 190 1 201 0 0 530 190 >Cog, (TEETH) 191 1 201 0 0 530 191 > >INDEX.PAT >NAME P1 CCA HP CCB PATT MAJOR1 MINOR1 > >Index map color, 199 47 17 0 0 530 199 >Index map color, 199 31 3 0 0 530 199 >Index map color, 199 79 57 0 0 530 199 >Index map color, 199 723 97 0 0 530 199 > > >LINE.PAT >NAME P1 MAJOR1 MINOR1 >none 0 0 0 Detailed unit descriptions are in files named "expl-*.txt" in http://pubs.usgs.gov/of/1992/ofr-92-0507/ CONTACT.PAT Geologic map units OFR-92-0507 NAME Abbreviation of geologic map unit OFR-92-0507 Qa Modern alluvium Qg Gravels and alluviums (Pinedale and Bull Lake age) Qgo Older gravels and alluviums (Pre-Bull Lake age) Qe Eolian deposits (Quaternary) Qeo Older eolian deposits (Quaternary) Qd Glacial drift of Pinedale and Bull Lake glaciations Qdo Older glacial drift (Pre-Bull Lake age) Qb Basalt Flows (Age <1.8 M.Y.) QTsa Unclassified surficial deposits and underlying Alamosa Formation QTa Ancient Alluvium To Ogallala Formation Tgv Bouldery gravel on old erosion surfaces in front range and never summer mountains Ta Arikaree formation Twr White river formation or group Th Huerfano formation Tcu Cuchara formation Tpc Poison canyon formation Tdu Upper part of Dawson arkose Tbp Browns park formation Tt Troublesome formation Tnp North park formation Tos Oligocene sedimentary rocks Tu Uinta formation Tb Bridger formation Tg Green river formation Tfp Parachute creek memeber - Green river formation Tgl Lower part - Green river formation Tglm Laney member - Green river formation Tgt Tipton tongue - Green river formation Tglu Luman tongue - Green River formation Tglw Lower part of Green river formation Tw Wasatch formation Twc Cathedral bluffs tongue - Wasatch formation Twn Niland tongue - Wasatch formation Two Wasatch formation and Ohio creek formation Tf Fort union formation Tc Coalmont formation Tm Middle park formation exclusive of windy gap member Td Dry union formation Ts Santa Fe formation Tos Oligocene sedimentary rocks Te Eocene prevolcanic sedimentary rocks Tsp South park formation Tlp Los Pinos formation Tsj San Jose formation Tn Nacimiento formation Tbb Basalt flows and associated tuff, breccia, and conglomerate of late-volcanic bimodal suite Tbbi Basaltic intrusive rocks related to basalt flows Tbr Rhyolitic intrusive rocks and flows of late-volcanic bimodal suite Tbrt Ash-flow tuff of late-volcanic bimodal suite Taf Ash-flow tuff of main volcanic sequence Tial Intra-ash flow andesitic lavas Tiql Intra-ash-flow quartz latitic lavas Tpl Pre-ash-flow andesitic lavas, breccians, tuffs, and conglomerates Twm Wall mountain tuff Tv Volcanic rocks in northwestern Colorado Tui Upper Tertiary intrusive rocks Tmi Middle tertiary intrusive rocks TKda Denver and Arapahoe formations Tdv Basaltic flows in Denver formation near Golden TKdl Denver formation or lower part of Dawson arkose TKr Raton formation TKa Animas formation TKec Telluride conglomerate of Eocene prevolcanic sedimentary rocks and Cimarron ridge formation TKi Laramide intrusive rocks Kl Laramie formation Kf Fox hills sandstone Klf Laramie formation and fox hills sandstone Kvt Vermejo formation and Trinidad sandstone Kp Perre shale, undivided Kpu Upper unit - Pierre shale Kpl Lower unit - Pierre shale Kn Niobrara formation Kcg Carlile shale, greenhorn limestone, and graneros shale Kc Colorado group Kpg Pierre shale, Niobrara, and Carlile, Greenhorn, and Graneros formations, undivided Kdp Dakota sandstone and Purgatoire formation Kd Dakota sandstone or group Kl Lance formation Kmv Windy gap memeber Kls Lewis shale Kmv Mesaverde formation, undivided Kmvu Upper part - Mesaverde group Kmvl Lower part - Mesaverde group Kw Williams fork formation Ki Iles formation Ksc Sego sandstone, Buck tongue of Mancos shale, and Castlegate sandstone Kh Hunter canyon formation Kmgs Mount Garfield formation and Sego sandstone Km Mancos shale Kmfm Frontier sandstone and Mowry shale members and intervening shale zone Kfd Frontier sandstone and Mowry shale members of Mancos shale and Dakota sandstone Kdb Dakota sandstone and Burro canyon formation Kkf Kirtland shale and Fruitland formation Kpcl Pictured cliffs sandstone and Lewis shale Kch Cliff house sandstone Kmp Menefee formation and Point lookout sandstone KJdm Dakota and Morrison formations KJdj Dakota, Burro canyon, Morrison, and Junction creek formations KJdw Dakota, Burro Canyon, Morrison, and Wanakah formations KJdr Dakota group and Morrison and Ralston creek formations at mountain front between Boulder and Colorado Springs KJde Dakota and other formations depending on location KJds Dakota, Morrison, and Sundance formations Jm Morrison formation Jmj Morrison formation and Junction creek sandstone Jmc Morrison formation and curtis formation Jmw Morrison formation and Wanakah formation Jmr Morrison formation and Ralston creek formation Jme Morrison formation and Entrada sandstone Jms Morrison formation and Sundance formation Jmse Morrison formation, Summerville formation, and Entrada sandstone Jmce Morrison, Curtis, and Entrada formations Jmre Morrison, Ralston creek, and Entrada formations Jmwe Morrison, Wanakah, and Entrada formations J@g Glen canyon sandstone J@gc Glen canyon group and Chinle formation J@mg Morrison, Curtis, Entrada, and Glen canyon formations J@mc Morrison, Entrada, and Chinle formations @kc Kayenta formation, Wingate sandstone, and Chinle formation @wc Wingate sandstone and Chinle formation @m Moenkopi formation @ch Chugwater formation @cc Chinle and Chugwater formations @c Chinle formation @d Dolores formation @dg Dockum group @Pl Lykins formation @Ps State bridge formation @Pll Lykins formation and Lyons sandstone @Pjs Jelm, Lykins, Lyons, and Satanka formations @Pcs Chinle and State bridge formations @Pcp Chinle, Moenkopi, and Park City formations @Pr Triassic and Permian rocks @Pdc Dolores formation and Cutler formation @Pmc Moenkopi formation and Cutler formation @&lf Lykins, Lyons, and Fountain formations Pp Park city formation Pu Upper Permian rocks, undivided Pc Cutler formation Mz Mesozoic rocks MzPz Mesozoic and Paleozoic rocks P&f Fountain formation P&cf Casper formation and Lower part of Fountain formation P&if Ingleside formation and Fountain formation P&s Sangre de Cristo formation P&m Maroon formation P&w Weber sandstone P&wm Weber sandstone and Maroon formation &m Minturn formation in west-central and south-central and other units of middle Pennsylvanian age &b Belden formation &mb Minturn and Belden formations &ee Evaporitic facies &mbe Evaporitic facies of Minturn and Belden formations in South Park and southward &h Hermosa formation &rh Rico and Hermosa formations &mr Morgan formation and Round Valley limestone M_ Leadville limestone, Williams canyon limestone, Manitou limestone, and Sawatch quartzite MDO Leadville limestone, Williams canyon limestone, and one or more Ordovician formations DO_ Williams canyon limestone, Manitou Limestone, and Sawatch quartzite O_ Manitou limestone and Sawatch quartzite Or One or more Ordovician formations MD Leadville limestone, Gilman sandstone, Dyer dolomite, and parting formation MD_ Leadville, Gilman, Dyer, Parting, and Sawatch formations DO Parting, Fremont, and Harding formations _s Sawatch quartzite Mm Madison limestone _l Lodore formation M_ml Madison limestone and Lodore formation Md_ Leadville Limestone, Ouray Limestone, Elbert formation, and Ignacio quartzite _am Alkalic nad mafic intrusive rocks in small plutons, and diabase dikes Yu Uinta mountain group YXu Uncompahgre formation Xb Biotitic gneiss, schist, and migmatite Xfh Felsic and hornblendic gneiss Xq Quartzite, conglomerate, and interlayered mica schist Wr Red creek quartzite Yp Rocks of Pikes peak batholith Yg Granitic rocks of 1,400-M.Y. age group Yam Alkalic and mafic rocks in small plutons, and diabase and gabbro dikes Xg Granitic rocks of 1,700-M.Y. age group Xm Mafic rocks of 1,700-M.Y. age group YXg Granitic rocks of 1,400- and 1,700-M.Y. age groups U.S. Geological Survey Information Services mailing and physical address

Open-File Reports, PO Box 25286, Denver Federal Center

Denver CO 80225-0046 USA 1-888-ASK-USGS infoservices@usgs.gov This report is preliminary and has not been reviewed for conformity with U.S. Geological Survey (USGS) editorial standard nor with the North American stratigraphic codes. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the USGS. Although these data have been used by the USGS and have been successfully imported into data base programs, no warranty, expressed or implied, is made by the USGS as to how successfully or accurately the data can be imported into any specific application software running on any specific hardware platform. The fact of distribution shall not constitute any such warranty, and no responsibility is assumed by the USGS in connection therewith. This data base GIS is not meant to be used or displayed at any scale other than 1:500,000. USGS Open-File Report 92-507 ARC/INFO export 6.1.2 Geologic units and structural features gzip and tar 5 megabytes http://pubs.usgs.gov/of/1992/ofr-92-0507/colorado.tar.gz none 19990408 20030227 U.S. Geological Survey Gregory N. Green mailing and physical address

MS 905, USGS, Denver Federal Center

Denver CO 80225 USA 1-303-236-5390 ggreen@usgs.gov Content Standard for Digital Geospatial Metadata FGDC-STD-001-1998