Great Sand Dunes National Park and Preserve National Park Service Colorado U.S. Department of the Interior Geologic Map of Great Sand Dunes
Geologic Units Qal - alluvium Xgn Qbf PNmu PNml Qaf - alluvial-fan deposits NP and PRES Qes - eolian sand Qpf Xsm PPNsl Qdf - dunefield Ql Qssh - sand sheet PPNsc Qsbk - sabkha Qpf Xsm Ql - landslide deposits Qrf - rockfall deposits Qpf PPNsc Xgn Qrg - rock-glacier deposits
PPNsl Qpu - Pinedale glacial deposits, undifferentiated Qes Qbf PNmu Qpf - Pinedale fan allluvium
Qpl - Pinedale lacustrine clay Qpf Qal Qbf PNmu Qpo - Pinedale outwash
Yqm Qpt - Pinedale till Qes Qpf
Qbt Qpbu - Pinedale and Bull Lake glacial deposits, undifferentiated Qbf Ql Qbf - Bull Lake fan alluvium Qbo Qpt Qbt PPNsc Qbo - Bull Lake outwash Qpf Ql Ts Ts Qbo2 - Bull Lake young outwash Qbf Qpt Qbt - Bull Lake till Qal Qbt2 - Bull Lake young till
PNm Xgn Ts - Sante Fe Formation Qpt Qbf Tgr - granite and granodiorite Qes Xqm Qpf Qpt Ta - andesite Tmv Tmv - mafic volcanic rocks Qes Xgn PPNsu Qpt Xqm Xgn Ts Tf - felsic dikes
Tm - mafic dikes Qbf Jm - Morrison Formation Xlgn Qpf Xqm Je - Entrada Sandstone Xgn PPNsc Ts Xgn PPNsu - Sangre de Cristo Formation (undivided) PPNsc - Sangre de Cristo Formation, Crestrone Member
Xgn Xgn PPNscd - Sangre de Cristo Formation, Crestrone Member Xlgn PPNsl - Sangre de Cristo Formation, Lower Member PPNsc Ts PNm - Minturn Formation Xgn PNmu - Minturn Formation, upper part
Xgn PNmumls - Minturn Formation, marker limestone Xgn Tmv PNmcls - Minturn Formation, crinoidal silty limestone
Qssh PNmush - Minturn Formation, shale and siltstone member PNmols - Minturn Formation, oolite limestone Qssh Ts PNmt - Minturn Formation, Main turbidite member
PNmbls - Minturn Formation, biohermal limestone unit Qssh Xgn PNml - Minturn Formation, lower part Qdf PNmq - Minturn Formation, quartzose red-beds
Ts MDOr - Mississippian, Devonian and Ordovician Sed Rocks
Oh - Harding Sandstone Xhgn Om - Manitou Limestone
Yqm - Quartz Monzonite
Yqmqz - Quartz Monzonite, vein quartz PNm Xp - pegmatite
Xto - tonalite gneiss
Xg - metagabbro Qsbk Xqd - quartz diorite Ta Xdi - diorite
Xm - mafic intrusive rocks Xgn Xhgn Xqm - quartz monzonite Qal Xq - quartzite
Xsm - syenite and monzonite
Ql Xlgn - leucocratic gniess Xdi Xhgn - horneblende gneiss
Xgn Xgn - mixed gneiss Ql Xto Xdi WATER PNm Qg
Xqd Xqd NPS Boundary Age Date Points Linear Geologic Units # Month Year paleontological PNmumls - Minturn Formation, marker limestone Qaf Xhgn Geologic Attitude and Observation Points Mine Point Features PNmcls - Minturn Formation, crinoidal silty limestone o N strike and dip of beds Prospect PNmubls - Minturn Formation, brown weathering limestone
Xto s strike and dip of overturned beds  Adit Xto PNmupals - Minturn Formation, phylloida algal limestone v Qg Ç strike of vertical beds Gravel Pit PNmols - Minturn Formation, oolite limestone e Xg horizontal beds Folds Linear Dike Units ¹ strike and dip of foliation known location Tf - felsite dike, ¨ strike of vertical foliation approximate location Tm - mafic rock dike Ü bearing and plunge of lineation concealed Yqmqz - vein quartz
È Faults strike and dip of cleavage Xp - pegmatite dike known location $ fold plunge arrow head Xm - mafic intrusives approximate location ® dip of fault plane Geologic Contacts concealed location known The original maps digitized by NPS staff to create this product were: U upthrown side of fault approximate Lindsey, David A., Soulliere, Sandra J., Hafner, Katrin,, and Flores, R.J., 1985, Geologic Map of Rito Alto Peak and Northeastern part of Mirage D downthrown side of fault Quadrangles, Custer and Saguache Counties, Colorado: U.S. Geological Survey, Miscellaneous Field Studies Map MF-1787, scale 1:24,000 . Ü @ approximate, queried monocline Lindsey, David A., Johnson, Bruce R., Soulliere, Sandra J., Bruce, Robert M., and Hafner, Katrin, 1986, Geologic Map of the Beck Mountain, map boundary Crestone Peak, and Crestone Quadrangles, Custer, Huerfano, and Saguache Counties, Colorado: U.S. Geological Survey, Miscellaneous Field F anticline Studies Map MF-1878,1:24,000 scale. shoreline M syncline Johnson, Bruce R., Bruce, Robert M., and Lindsey, David A., 1989, Reconnaissance Geologic Map of the Medano Pass Quadrangle and part of the Liberty Quadrangle, Alamosa, Huerfano, and Saguache Counties, Colorado: U.S. Geological Survey, Miscellaneous Field Studies Map MF- I overturned anticline 2089, scale 1:24,000. Z overturned syncline Bruce, Robert M., and Johnson, Bruce R., 1991, Reconnaissance Geologic Map of parts of the Zapata Ranch and Mosca Pass Quadrangles, Alamosa and Huerfano Counties, Colorado: U.S. Geological Survey, Miscellaneous Field Studies Map MF-2168, scale 1:24,000. V monocline, anticlinal bend
Johnson, Bruce R., and Bruce, Robert M., 1991, Reconnaissance Geologic Map of parts of the Twin Peaks and Blanca Peak Quadrangles, Alamosa, Costilla, and Huerfano Counties, Colorado: U.S. Geological Survey, Miscellaneous Field Studies Map MF-2169, scale 1:24,000.
Valdez, Andrew, 2000, unpublished geologic mapping of Great Sand Dunes National Park, Colorado. 0 3 6 12 • Miles Digital geologic data and cross sections for Great Sand Dunes National Park and Preserve, and all other digital geologic data prepared as part of the Geologic Resources Divisions Geologic Resource Evaluation program, are available online: http://www2.nature.nps.gov/geology/inventory/gre_publications.cfm 0 5 10 20 Kilometers Produced by Geologic Resources Division February 2006