![Page 1: COLORADO MOUNTAINSsnobear.colorado.edu/Adina/geog_3251/PPT/Rockies_geologic_history.pdfColorado Plateau San Luis Valley North, Middle, South Park. Never summer Rampart Range Uinta](https://reader033.vdocuments.mx/reader033/viewer/2022050105/5f43b0519c619a742b4e5719/html5/thumbnails/1.jpg)
Graphic created by Eduardo Iturrate at Research Systems, Inc.
COLORADO MOUNTAINS
Plains
Mountains
Colorado Plateau
San Luis Valley
North, Middle,South Park
![Page 2: COLORADO MOUNTAINSsnobear.colorado.edu/Adina/geog_3251/PPT/Rockies_geologic_history.pdfColorado Plateau San Luis Valley North, Middle, South Park. Never summer Rampart Range Uinta](https://reader033.vdocuments.mx/reader033/viewer/2022050105/5f43b0519c619a742b4e5719/html5/thumbnails/2.jpg)
Never summer
RampartRange
Uinta Mtns
Needle Mtns
Wet Mtns
Medicine Bow
Uncompahgre Mtns
ColoradoMtns
![Page 3: COLORADO MOUNTAINSsnobear.colorado.edu/Adina/geog_3251/PPT/Rockies_geologic_history.pdfColorado Plateau San Luis Valley North, Middle, South Park. Never summer Rampart Range Uinta](https://reader033.vdocuments.mx/reader033/viewer/2022050105/5f43b0519c619a742b4e5719/html5/thumbnails/3.jpg)
Boulder Area Stratigraphy
Be able to reproduce this figure on test!
![Page 4: COLORADO MOUNTAINSsnobear.colorado.edu/Adina/geog_3251/PPT/Rockies_geologic_history.pdfColorado Plateau San Luis Valley North, Middle, South Park. Never summer Rampart Range Uinta](https://reader033.vdocuments.mx/reader033/viewer/2022050105/5f43b0519c619a742b4e5719/html5/thumbnails/4.jpg)
BASEMENT ROCK
• Emplaced 1.4-1.7 Gy• Crystalline rock• Black Canyon of the
Gunnison: 1.7 Gy darkgneiss cut through bylighter 1.4 Gy granite andpegmatite
• Underlies most of presentday Colorado Rockies
![Page 5: COLORADO MOUNTAINSsnobear.colorado.edu/Adina/geog_3251/PPT/Rockies_geologic_history.pdfColorado Plateau San Luis Valley North, Middle, South Park. Never summer Rampart Range Uinta](https://reader033.vdocuments.mx/reader033/viewer/2022050105/5f43b0519c619a742b4e5719/html5/thumbnails/5.jpg)
GREAT UNCOMFORMITY
• An uncomformity is whenformations of differentages lay on top of eachother
• Another way to say this isthat part of the geologicrecord is missing
• From 1.2 Gy to 500 Mythe geologic record ismssing
![Page 6: COLORADO MOUNTAINSsnobear.colorado.edu/Adina/geog_3251/PPT/Rockies_geologic_history.pdfColorado Plateau San Luis Valley North, Middle, South Park. Never summer Rampart Range Uinta](https://reader033.vdocuments.mx/reader033/viewer/2022050105/5f43b0519c619a742b4e5719/html5/thumbnails/6.jpg)
TROPICAL SEAS RETURN
• 500 to 330 My• Sawatch sandstone
from beach sands(near GlenwoodSprings)
• Leadville limestonedeposited
• Missing in Boulderarea
![Page 7: COLORADO MOUNTAINSsnobear.colorado.edu/Adina/geog_3251/PPT/Rockies_geologic_history.pdfColorado Plateau San Luis Valley North, Middle, South Park. Never summer Rampart Range Uinta](https://reader033.vdocuments.mx/reader033/viewer/2022050105/5f43b0519c619a742b4e5719/html5/thumbnails/7.jpg)
FRONTRANGIA: 300 My
• Ancestral mountain range• 35 miles west of Boulder.• Streams carried eroded
sand and pebbles from theAncestral Rockies,dumping the material inwide deposits of gravel.
• These debris would laterbecome the Flatirons!
![Page 8: COLORADO MOUNTAINSsnobear.colorado.edu/Adina/geog_3251/PPT/Rockies_geologic_history.pdfColorado Plateau San Luis Valley North, Middle, South Park. Never summer Rampart Range Uinta](https://reader033.vdocuments.mx/reader033/viewer/2022050105/5f43b0519c619a742b4e5719/html5/thumbnails/8.jpg)
FOUNTAIN FORMATION: 270My
• Arkose sandstone, graveldeposits
• Sharp, angular points• Iron oxidiation, red color• Good climbing• Remnants of FrontRangia• Little transport• Flatirons, Red Rocks park,
Roxborough State Park
![Page 9: COLORADO MOUNTAINSsnobear.colorado.edu/Adina/geog_3251/PPT/Rockies_geologic_history.pdfColorado Plateau San Luis Valley North, Middle, South Park. Never summer Rampart Range Uinta](https://reader033.vdocuments.mx/reader033/viewer/2022050105/5f43b0519c619a742b4e5719/html5/thumbnails/9.jpg)
LYONS FORMATION: 250 My
• 220’ thick• Well-sorted, fine sand• Old sand dunes• Main building material
for CU-Boulder• Sea began to creep in
from the east• Arid to west
![Page 10: COLORADO MOUNTAINSsnobear.colorado.edu/Adina/geog_3251/PPT/Rockies_geologic_history.pdfColorado Plateau San Luis Valley North, Middle, South Park. Never summer Rampart Range Uinta](https://reader033.vdocuments.mx/reader033/viewer/2022050105/5f43b0519c619a742b4e5719/html5/thumbnails/10.jpg)
LYKINS FORMATION: 240 My
• Red color, soft, consisting mostly of shale,sandstone, and siltstone.
• 675’ thick,• Broad, flat floodplains
![Page 11: COLORADO MOUNTAINSsnobear.colorado.edu/Adina/geog_3251/PPT/Rockies_geologic_history.pdfColorado Plateau San Luis Valley North, Middle, South Park. Never summer Rampart Range Uinta](https://reader033.vdocuments.mx/reader033/viewer/2022050105/5f43b0519c619a742b4e5719/html5/thumbnails/11.jpg)
Entrada Sandstone: 150 My
• A desert environment with widespread sanddunes once again
• 30’ thick• Cross-bedded• Much more developed (thicker) around
Moab
![Page 12: COLORADO MOUNTAINSsnobear.colorado.edu/Adina/geog_3251/PPT/Rockies_geologic_history.pdfColorado Plateau San Luis Valley North, Middle, South Park. Never summer Rampart Range Uinta](https://reader033.vdocuments.mx/reader033/viewer/2022050105/5f43b0519c619a742b4e5719/html5/thumbnails/12.jpg)
MORRISON FORMATION: 140My
• Broad, swampylowlands, floodplains
• Lake and streamdeposits, mostly clays,Volcanic ash, Wildcolors
• Massive amounts ofdinosaur fossils; hasbeen described as abone yard.
![Page 13: COLORADO MOUNTAINSsnobear.colorado.edu/Adina/geog_3251/PPT/Rockies_geologic_history.pdfColorado Plateau San Luis Valley North, Middle, South Park. Never summer Rampart Range Uinta](https://reader033.vdocuments.mx/reader033/viewer/2022050105/5f43b0519c619a742b4e5719/html5/thumbnails/13.jpg)
MORRISON DINOSAURS AHOAX
• Fossils from the DNM quarry represent a water-transported and processed assemblage, not an insitu ecosystem.
• The "mass accumulation" of dinosaur bones atDNM, a sort of trademark feature for the MorrisonFormation in the American West, represents amystery that lacks satisfactory explanation.
• Clams, snails, and dismembered dinosaurs withinthe same deposit demonstrate a waterycatastrophe. (Noah’s ark flood?)
• http://www.icr.org/pubs/imp/imp-370.htm
![Page 14: COLORADO MOUNTAINSsnobear.colorado.edu/Adina/geog_3251/PPT/Rockies_geologic_history.pdfColorado Plateau San Luis Valley North, Middle, South Park. Never summer Rampart Range Uinta](https://reader033.vdocuments.mx/reader033/viewer/2022050105/5f43b0519c619a742b4e5719/html5/thumbnails/14.jpg)
DAKOTA FORMATION: 135 My
• shoreline of theCretaceous WesternInterior Seaway, massivesea to the east
• Lots of dinosaur tracks,but few fossils
• Mostly sandstones, someshales, 320’ thick
• First hogback (resistentridge)
![Page 15: COLORADO MOUNTAINSsnobear.colorado.edu/Adina/geog_3251/PPT/Rockies_geologic_history.pdfColorado Plateau San Luis Valley North, Middle, South Park. Never summer Rampart Range Uinta](https://reader033.vdocuments.mx/reader033/viewer/2022050105/5f43b0519c619a742b4e5719/html5/thumbnails/15.jpg)
NEXT 70 My• marked by several advances and retreats of the sea.• The deposits associated with these episodes of marine
flooding consist of shale, sandstone, limestone, and somebeds of coal.
• The environments suggested by the rocks include the deepsea, sandy beaches, and coast swamps.
• Names applied to the various formations are (from oldestto youngest): the Benton Shale, Niobrara Limestone, PierreShale, Fox Hills Sandstone, and the Laramie Formation.Together these formations total over 10,000 feet ofsediment.
![Page 16: COLORADO MOUNTAINSsnobear.colorado.edu/Adina/geog_3251/PPT/Rockies_geologic_history.pdfColorado Plateau San Luis Valley North, Middle, South Park. Never summer Rampart Range Uinta](https://reader033.vdocuments.mx/reader033/viewer/2022050105/5f43b0519c619a742b4e5719/html5/thumbnails/16.jpg)
PIERRE SHALE
• Up to 9,000’ thick• Deposited by an
inland sea• Lots of dinosaurs,
such as thispterodactyl
• City of Boulder builton Pierre Shale
![Page 17: COLORADO MOUNTAINSsnobear.colorado.edu/Adina/geog_3251/PPT/Rockies_geologic_history.pdfColorado Plateau San Luis Valley North, Middle, South Park. Never summer Rampart Range Uinta](https://reader033.vdocuments.mx/reader033/viewer/2022050105/5f43b0519c619a742b4e5719/html5/thumbnails/17.jpg)
70 My
• 70 million years ago, the sea slowlywithdrew to the northeast.
• It left behind vast swamps, from which thecoals of the Laramie Formation formed.
• Explains natural gas deposits in DenverBasin
• The withdrawal of the sea took about 10 to15 million years.
![Page 18: COLORADO MOUNTAINSsnobear.colorado.edu/Adina/geog_3251/PPT/Rockies_geologic_history.pdfColorado Plateau San Luis Valley North, Middle, South Park. Never summer Rampart Range Uinta](https://reader033.vdocuments.mx/reader033/viewer/2022050105/5f43b0519c619a742b4e5719/html5/thumbnails/18.jpg)
LARAMIDE OROGENY• 70-40 My ago• High angle thrust faults,
Reverse fault• Uplift of Precambrian
basement• Deformation of overlying
Paleozoic & Mesozoicsedimentary rocks, egFountain Formation,Lyons Formation
![Page 19: COLORADO MOUNTAINSsnobear.colorado.edu/Adina/geog_3251/PPT/Rockies_geologic_history.pdfColorado Plateau San Luis Valley North, Middle, South Park. Never summer Rampart Range Uinta](https://reader033.vdocuments.mx/reader033/viewer/2022050105/5f43b0519c619a742b4e5719/html5/thumbnails/19.jpg)
Colorado Mineral Belt
• Emplaced duringLaramide Orogenyand during volcanismimmediately afterward
• Hydrothermalemplacements causedformations of mineralveins
• Almost all mineral athigh elevation
![Page 20: COLORADO MOUNTAINSsnobear.colorado.edu/Adina/geog_3251/PPT/Rockies_geologic_history.pdfColorado Plateau San Luis Valley North, Middle, South Park. Never summer Rampart Range Uinta](https://reader033.vdocuments.mx/reader033/viewer/2022050105/5f43b0519c619a742b4e5719/html5/thumbnails/20.jpg)
SAN JUAN VOLCANICS
• Ash-flow eruptions inthe SW corner of stateabout 30 My
• Silverton Caldera• Formation of San Juan
mountains
![Page 21: COLORADO MOUNTAINSsnobear.colorado.edu/Adina/geog_3251/PPT/Rockies_geologic_history.pdfColorado Plateau San Luis Valley North, Middle, South Park. Never summer Rampart Range Uinta](https://reader033.vdocuments.mx/reader033/viewer/2022050105/5f43b0519c619a742b4e5719/html5/thumbnails/21.jpg)
EPIEROGENIC UPLIFT
• 28 My to present• Broad, regional uplift with little tilting• 10 My really kicked into gear• Still continuing
![Page 22: COLORADO MOUNTAINSsnobear.colorado.edu/Adina/geog_3251/PPT/Rockies_geologic_history.pdfColorado Plateau San Luis Valley North, Middle, South Park. Never summer Rampart Range Uinta](https://reader033.vdocuments.mx/reader033/viewer/2022050105/5f43b0519c619a742b4e5719/html5/thumbnails/22.jpg)
THE BIG DOME• Uplifted all of western and
central Colorado• Reason so many 14’er• Dome is centered under near
Leadville• Center of 14’ers• Antecedent rivers invigorated:
Black Canyon, Gore River,Roaring Fork, Royal Gorge
• Rivers flow in radial patternfrom dome: North Platte,Colorado to west, Arkansas tosouth, South Platte to east
![Page 23: COLORADO MOUNTAINSsnobear.colorado.edu/Adina/geog_3251/PPT/Rockies_geologic_history.pdfColorado Plateau San Luis Valley North, Middle, South Park. Never summer Rampart Range Uinta](https://reader033.vdocuments.mx/reader033/viewer/2022050105/5f43b0519c619a742b4e5719/html5/thumbnails/23.jpg)
RIO GRANDE RIFT
• Also 28 My-present• Runs south-north• Cuts across previous faults• Forms San Luis Valley,
Arkansas River graben• Continues on to Wyoming• Still growing• May connect in future to
the Gulf of California
![Page 24: COLORADO MOUNTAINSsnobear.colorado.edu/Adina/geog_3251/PPT/Rockies_geologic_history.pdfColorado Plateau San Luis Valley North, Middle, South Park. Never summer Rampart Range Uinta](https://reader033.vdocuments.mx/reader033/viewer/2022050105/5f43b0519c619a742b4e5719/html5/thumbnails/24.jpg)
PLEISTOCENE ICE AGE
• 1.5 My to 12,000 yrs• Glaciated down to
about 8,000’ elevation• Glacial erosion shaped
modern mountains