Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.
Geologic History of the Denver Area
MJD 3/2016 1
Geologic History of the Denver Area
The Usual and the Unusual
Geology of the Denver Area
By
Michael Delvaux
MJD 3/2016 2
Geologic History of the Denver Area
• Disclaimer: This presentation is meant to give an overall top level history (sequenc...
Geologic History of the Denver Area
• Introduction
– 3 Classifications and what they mean
IGNEOUS
SEDIMENTARY
METAMORPHIC
...
Geologic History of the Denver Area
• Introduction
Igneous Classification
Crystals High Content of In Between Low Content ...
Geologic History of the Denver Area
• Introduction
Igneous Rocks – What’s Cool
Different elements and minerals crystalize ...
Geologic History of the Denver Area
• Introduction
Sedimentary Rocks – What’s Cool
Material is eroded, transported and dep...
Geologic History of the Denver Area
• Introduction
Sedimentary Rocks – What Else Is Cool
Rock formations below are older ...
Geologic History of the Denver Area
• Introduction
Hundreds
Of
Feet
Hundreds of Miles
MJD 3/2016 9
Example of
Walther’s Pr...
Geologic History of the Denver Area
• Introduction
That’s cool but what could can an amateur
determine?
Stream and
river c...
Geologic History of the Denver Area
• Introduction
Flow Direction?
MJD 3/2016 11
Geologic History of the Denver Area
• Introduction
MJD 3/2016 12
Geologic History of the Denver Area
• Introduction
Faults
MJD 3/2016 13
Geologic History of the Denver Area
• Fossils (from Latin fossus, literally "having been dug up") are the
preserved remain...
Geologic History of the Denver Area
• Introduction
– Time Chart
MJD 3/2016 15
Picture Ref: Abbott
• Our Story Begins
Geologic History of the Denver Area
13Bya
4.5ByaMJD 3/2016 16Now
First there was the Big Bang
• Our Story Begins
Geologic History of the Denver Area
Big Bang
13Bya
4.5ByaMJD 3/2016 17Now
• Our Story Begins
Geologic History of the Denver Area
Big Bang
13Bya
4.5ByaMJD 3/2016 18
Supernovas create heavy elements...
• Our Story Begins
– Cool Place: Chamberlain Observatory
• Observatory Park, Denver, Colorado
Geologic History of the Denv...
• Our Story Begins
Geologic History of the Denver Area
Big Bang
13Bya
4.5Bya
Solar Nebula
MJD 3/2016 20Now
• Our Story Begins
Geologic History of the Denver Area
13Bya
4.5ByaMJD 3/2016 21
Earth FormationSolar Nebula
Now
• Our Story Begins
Geologic History of the Denver Area
Big Bang
13Bya
4.5Bya
Solar Nebula Earth Formation Canadian Shield ...
Geologic History of the Denver Area
• Amalgamation of Early North America
(Laurentia)
MJD 3/2016
23
Ref: Hoffman, Jones
13...
Geologic History of the Denver Area
• Yavapai Orogeny
13Bya
4.5Bya 2.45Bya
Big Bang
Earth Formation
Canadian Shield
Forms
...
Geologic History of the Denver Area
13Bya
4.5Bya 2.45Bya
Big Bang
Earth Formation
Canadian Shield
Forms
1.76Bya
Yavapai Or...
Geologic History of the Denver Area
• Cool Place: Bioherms (stromatolites) in the
Medicine Bow Mountains of S.Wyoming
MJD ...
Geologic History of the Denver Area
• Cool Place: Bioherms (stromatolites) in the
Medicine Bow Mountains of S.Wyoming
MJD ...
Geologic History of the Denver Area
• Denver Area Rocks of Yavapai Orogeny Time
Gneisses and Schists
Volcanic Arc produced...
Geologic History of the Denver Area
• Denver Area Rocks of Yavapai Orogeny Time
MJD 3/2016 29
Ref: Kellog
Geologic History of the Denver Area
• Mazatzal Orogeny
13Bya
4.5Bya 2.45Bya
Big Bang
Earth Formation
Canadian Shield
Forms...
Geologic History of the Denver Area
• No Denver Area Rocks are from the Mazatzal
Orogeny
Gneisses, Schists, and intrusions...
Geologic History of the Denver Area
• A third stage set of igneous plutonic pulses
occurred in the Arizona, New Mexico, an...
Geologic History of the Denver Area
• Iron Dike Intrusion
– Dark-gray to black ferrogabbro; weathers dark brown to orange ...
• Grenville Orogeny
Geologic History of the Denver Area
13Bya
4.5Bya 2.45Bya
Big Bang
Earth Formation
Canadian Shield
Form...
• Grenville Orogeny
Geologic History of the Denver Area
13Bya
4.5Bya 2.45Bya
Big Bang
Earth Formation
Canadian Shield
Form...
Geologic History of the Denver Area
• Pikes Peak Batholith
– 3 Intrusive Centers
• Pikes Peak
• Buffalo Park
• Lost Park
–...
Geologic History of the Denver Area
• Sandstone Dikes
– Extremely unusual feature that occurs within the
Pikes Peak Granit...
Geologic History of the Denver Area
• Sandstone Dikes (Very Unusual)
– Cool Place: Highway 126 (Pine Valley Rd)
Granite Gr...
• Cambrian Period
– Explosion of Multicellular Life
– Marks the beginning of the Phanerozoic Eon /
Paleozoic Era
– Earth f...
• Cambrian Period -> Ordovician Period
– Started with no deposition and ended with
flooding by shallow sea in Colorado
• U...
• Ordovician Period -> Silurian Period
– Shallow Sea followed by no deposition in
Colorado.
Geologic History of the Denver...
• Silurian Period -> Devonian Period
– Shallow Sea transgression across Colorado.
– Eurasian/African Plate encroaches NA p...
• Kimberlite Diatremes
– Widespread clusters of deep mantle derived volcanic
activity occurred in the West from Very late
...
• Kimberlite Diatremes
Geologic History of the Denver Area
Economics of these diatremes:
0 to 100 carats per 100 tons.
MJD...
• Kimberlite Diatremes
Geologic History of the Denver Area
Cool Unusual Place near Denver:
Boulder’s Green Mountain Diatre...
• Devonian Period -> Mississippian Period
– Shallow Sea still across Colorado.
– Eurasian/African Plate encroaches NA plat...
• Mississippian -> Pennsylvanian Period
Geologic History of the Denver Area
Ancestral
Rockies
Appalachians
Atlas Mtns
MJD ...
Geologic History of the Denver Area
• The Great Colorado Unconformity
– Uplift of Ancestral Rockies eroded all previously
...
• Pennsylvanian Period -> Permian Period
Geologic History of the Denver Area
MJD 3/2016 49
Ref: Blakey
• Permian Period
– Supercontinent Pangea
– Continued erosion of Ancestral Rockies.
– Large scale wind blown Sand dunes and...
• Permian Period
– Mud cracks (Matthews) or freezing/thawing cracks
(Abbott) in Lyons formation in Morrison city limits.
G...
• Triassic Period
– No trace of Ancestral Rockies remain
– Lykins Formation
• Low lying mudflats with interfingering marin...
• Jurassic Period
– Breakup of supercontinent Pangea
– Morrison Formation
• Ancient river channel and flood plains deposit...
• Jurassic Period
– Morrison Formation
• Cross Section of current ripples at Dinosaur Ridge
Geologic History of the Denver...
• Cretaceous Period
– Dakota Formation
• Cyclical occurrences of ancient river channel deposits
progressing into tidal fla...
• Cretaceous Period
– Dakota Formation
Geologic History of the Denver Area
Track site
MJD 3/2016
56
• Cretaceous Period
– Dakota Formation
Geologic History of the Denver Area
U Shaped burrows in Tidal Flat
MJD 3/2016 57
• Cretaceous Period
– Cretaceous Interior Seaway
• Over 5000 feet of marine deposits
– Benton, Niabrara, and Pierre Format...
• Cretaceous Period
– Cretaceous Interior Seaway
Geologic History of the Denver Area
Seaway Deposits
MJD 3/2016 59
• Cretaceous Period
– Cretaceous Interior Seaway
Geologic History of the Denver Area
MJD 11/2016 60
Ref: Blakey, Wikipedia
• Cretaceous Period
– Uplift: Retreat of the Seaway and rise of the Rockies
• Compression in the North American plate caus...
• Cretaceous Period
Geologic History of the Denver Area
MJD 3/2016 62
Ref: Abbott
• Late Cretaceous Period
Geologic History of the Denver Area
MJD 3/2016 63
Ref: Abbott
• Late Cretaceous Period
– KT Boundary
• Most famous extinction event of all (extinction of the
dinosaurs)
• Cool Place: S...
• Paleocene Epoch
– Golden Fault was still active
– Erosion continued into the crystalline basement rocks
and formed a rou...
• Paleocene Epoch
Geologic History of the Denver Area
MJD 3/2016 66
Ref: Abbott
• Paleocene Epoch
– Cool Place: North and South Table Mountains
• 3 lava flows on North Table Mountain
• 2 lava flows on S...
• Paleocene Epoch
Geologic History of the Denver Area
MJD 3/2016 68
Ref: Abbott
• Eocene Epoch (58 – 37 mya)
– Front Range Volcanoes went extinct.
– Golden Fault went dormant.
– Major erosion period bur...
• Eocene Epoch
Geologic History of the Denver Area
(Saprolite – intense chemical weathering of gneiss. Current top of Look...
• Eocene Epoch
– Ignimbrite Flare-up
• One of the most extensive episodes of high-silica volcanism
(high explosive) in the...
• Eocene Epoch
– Wall Mountain Tuff – Hot incandescent cloud of ash
and gas raced across central Colorado to the vicinity ...
• Eocene Epoch
– Wall Mountain Tuff
Geologic History of the Denver Area
Topography was
different than it is
today
MJD 3/20...
• Eocene Epoch
– Massive Flooding - Castle Rock Conglomerate
• Extensive flooding brought large stones from as far away as...
• Eocene Epoch
– Castle Rock Conglomerate
• Massive flooding carves canyon in
Wall Mountain Tuff.
Geologic History of the ...
• Eocene Epoch
– Castle Rock Conglomerate
• Massive flooding brings material
from as far away as Boulder CO.
Geologic Hist...
• Eocene Epoch
– Florissant Formation
• Guffey Volcanic
eruptions
– After Wall Mountain
– Buries leaves, insects,
and fish...
• Oligocene, Miocene, and Pliocene Epochs
– Continued regional uplift to 5000 ft
– Erosion: Incision of canyons and valley...
• Pleistocene Epoch
– Cool Place: Mount Morrison Slide in Matthews Winters
Park. Massive landslide deposit when the valley...
• Pleistocene Epoch
– Glaciation in the mountains
– Cool Place: Valleys of Rocky Mountain
National Park
– Cool Place: Lamb...
• Modern Times
– Earliest human inhabitants ~8400 years ago as
evidenced by spear points and bison bones at
Lamb Spring (L...
Geologic History of the Denver Area
• References
Abbott,A. and Cook,T. 2012, Geology Underfoot Along Colorado’s Front Rang...
Geologic History of the Denver Area
• References
Knight,S.H., 1968, Precambrian staromatolite bioherms and reefs in the lo...
Geologic History of the Denver Area
• Field Trip:
• Bring:
– Water
– Hiking food
– Magnifying glass
– Camera
– Sun Protect...
Geologic History of Denver
– Locations:
• Chamberlain Observatory
• Bioherms – Medicine Bow Mtns
• Iron Dike* - Boulder
• ...
Geologic History of Denver
– Locations:
• Dinosaur Ridge – Morrison FM and Dakota FM
• Benton FM – Morrison
• Niabrara – M...
Geologic History of Denver
– Locations:
• Paleocene – N and S Table Mountains
• Wall Mountain Tuff – Castle Rock
• Castle ...
Upcoming SlideShare
Loading in …5
×

Denver Area Geology

1,043 views

Published on

Complete Brief Geologic History of the Denver, Colorado area

Published in: Science
  • Be the first to comment

Denver Area Geology

  1. 1. Geologic History of the Denver Area MJD 3/2016 1
  2. 2. Geologic History of the Denver Area The Usual and the Unusual Geology of the Denver Area By Michael Delvaux MJD 3/2016 2
  3. 3. Geologic History of the Denver Area • Disclaimer: This presentation is meant to give an overall top level history (sequence of events) of the major events that occurred in the Denver area from the beginning of time. It is not meant to serve any other purpose. The published sources from which many of the pictures and graphics that were used are listed at the end. There were some pictures and graphics that were collected from the internet over the years that I do not have references for. Some of the photographs I have taken myself. • Due to the uplift of the Rocky Mountains, there are good exposures to a lot of the geologic history. Unlike other places in the world, there are a number of rather unusual (not un-natural or un-explainable) things that have occurred here which I have attempted to point out. • I have attempted to point out at least one location in the area that contains evidence for the current theory of these major events. • For those really interested, I could offer my services up as a guide. Friend me and message me on my Linkedin site (Public Profilehttps://www.linkedin.com/in/michael- delvaux-3244052). MJD 3/2016 3
  4. 4. Geologic History of the Denver Area • Introduction – 3 Classifications and what they mean IGNEOUS SEDIMENTARY METAMORPHIC MJD 3/2016 4
  5. 5. Geologic History of the Denver Area • Introduction Igneous Classification Crystals High Content of In Between Low Content of Orthoclase Feldspar Mixtures Orthoclase Feldspar Quartz Quartz Low Content of High Content of Plagioclase Feldspar Plagioclase Feldspar Macroscopic Granite Quartz Monzonite Gabbro Crystals Granodiorite Diorite Microscopic Rhyolite Quartz Latite Basalt Crystals Dacite Andesite Extrusive Behavior Extrusive Behavior Explosive Volcanic Non explosive Ash most common non viscous thin Or thick Volcanic lava Viscous Lava MJD 3/2016 5
  6. 6. Geologic History of the Denver Area • Introduction Igneous Rocks – What’s Cool Different elements and minerals crystalize out of a cooling magma at different temperatures. Radioactive Isotope parents (like U238) crystalize at a different temperature than their daughter products (like Pb206). Since they start at a pure state they can be used to measure time. MJD 3/2016 6 Ref: wikipedia
  7. 7. Geologic History of the Denver Area • Introduction Sedimentary Rocks – What’s Cool Material is eroded, transported and deposited. The depositional environments have discernable recognizable features. Erosion Alluvial fan Fluvial Shoreface Marine MJD 3/2016 7 Picture Ref: Weimer
  8. 8. Geologic History of the Denver Area • Introduction Sedimentary Rocks – What Else Is Cool Rock formations below are older than rock formations above.  Law of Superposition – Nicoli Steno 1669 Rock formations that reside vertically from one another were deposited horizontally from one another  Walther’s Principle – Johannes Walther 1893 ( first suggested by: Amanz Gressly 1838) MJD 3/2016 8
  9. 9. Geologic History of the Denver Area • Introduction Hundreds Of Feet Hundreds of Miles MJD 3/2016 9 Example of Walther’s Principle
  10. 10. Geologic History of the Denver Area • Introduction That’s cool but what could can an amateur determine? Stream and river current directions MJD 3/2016 10
  11. 11. Geologic History of the Denver Area • Introduction Flow Direction? MJD 3/2016 11
  12. 12. Geologic History of the Denver Area • Introduction MJD 3/2016 12
  13. 13. Geologic History of the Denver Area • Introduction Faults MJD 3/2016 13
  14. 14. Geologic History of the Denver Area • Fossils (from Latin fossus, literally "having been dug up") are the preserved remains or of animals, plants, and other organisms from the remote past. • Trace fossils, also called ichnofossils (sg. pronounced /ˈɪknoʊfɒsɨl/, from Greek: ιχνος ikhnos "trace, track"), are geological records of biological activity. Trace fossils may be impressions made on the substrate by an organism: for example, burrows, borings (bioerosion), footprints and feeding marks, and root cavities. MJD 3/2016 14
  15. 15. Geologic History of the Denver Area • Introduction – Time Chart MJD 3/2016 15 Picture Ref: Abbott
  16. 16. • Our Story Begins Geologic History of the Denver Area 13Bya 4.5ByaMJD 3/2016 16Now First there was the Big Bang
  17. 17. • Our Story Begins Geologic History of the Denver Area Big Bang 13Bya 4.5ByaMJD 3/2016 17Now
  18. 18. • Our Story Begins Geologic History of the Denver Area Big Bang 13Bya 4.5ByaMJD 3/2016 18 Supernovas create heavy elements Ref: Wikipedia Now
  19. 19. • Our Story Begins – Cool Place: Chamberlain Observatory • Observatory Park, Denver, Colorado Geologic History of the Denver Area MJD 3/2016 19 Ref: Wikipedia
  20. 20. • Our Story Begins Geologic History of the Denver Area Big Bang 13Bya 4.5Bya Solar Nebula MJD 3/2016 20Now
  21. 21. • Our Story Begins Geologic History of the Denver Area 13Bya 4.5ByaMJD 3/2016 21 Earth FormationSolar Nebula Now
  22. 22. • Our Story Begins Geologic History of the Denver Area Big Bang 13Bya 4.5Bya Solar Nebula Earth Formation Canadian Shield Begins to form 2.45ByaMJD 3/2016 22 Ref: Abbott, HoffmanPrecambrian Now
  23. 23. Geologic History of the Denver Area • Amalgamation of Early North America (Laurentia) MJD 3/2016 23 Ref: Hoffman, Jones 13Bya 4.5Bya 2.45Bya Big Bang Earth Formation Canadian Shield Forms Precambrian Now
  24. 24. Geologic History of the Denver Area • Yavapai Orogeny 13Bya 4.5Bya 2.45Bya Big Bang Earth Formation Canadian Shield Forms 1.76Bya Yavapai Orogeny Yavapai Orogeny: Mountain building as a result of the accretion of the Colorado Volcanic Arc to Laurentia PrecambrianMJD 3/2016 24 Ref: Abbott, Hoffman, Now
  25. 25. Geologic History of the Denver Area 13Bya 4.5Bya 2.45Bya Big Bang Earth Formation Canadian Shield Forms 1.76Bya Yavapai Orogeny Precambrian Yavapai Orogeny Cynobacteria formed stromatolites in the back arc shallow environments MJD 3/2016 25 Ref: Abbott, Hoffman, Snoke, Knight Now
  26. 26. Geologic History of the Denver Area • Cool Place: Bioherms (stromatolites) in the Medicine Bow Mountains of S.Wyoming MJD 3/2016 26 Ref: Snoke, Knight
  27. 27. Geologic History of the Denver Area • Cool Place: Bioherms (stromatolites) in the Medicine Bow Mountains of S.Wyoming MJD 3/2016 27
  28. 28. Geologic History of the Denver Area • Denver Area Rocks of Yavapai Orogeny Time Gneisses and Schists Volcanic Arc produced thousands of feet of sediment of which burial pressure and heat metamorphosed. Boulder Creek Granodiorite (batholith) Igneous plutonic rock composed of both plagioclase and orthoclase feldspars due to the melting and mixing of both the continental crustal granites and oceanic crustal basalts Coal Creek Quartzite Metamorphosed sandstones and conglomerates from erosion of mountains and continental rocks. MJD 3/2016 28 Ref: Cole, Kellog
  29. 29. Geologic History of the Denver Area • Denver Area Rocks of Yavapai Orogeny Time MJD 3/2016 29 Ref: Kellog
  30. 30. Geologic History of the Denver Area • Mazatzal Orogeny 13Bya 4.5Bya 2.45Bya Big Bang Earth Formation Canadian Shield Forms 1.76Bya Yavapai Orogeny Mazatzal Orogeny: Mountain building as a result of the accretion of succeeding volcanic arcs. Precambrian Mazatzal Orogeny 1.65Bya MJD 3/2016 30 Ref: Abbott, Hoffman, Now
  31. 31. Geologic History of the Denver Area • No Denver Area Rocks are from the Mazatzal Orogeny Gneisses, Schists, and intrusions at the Royal Gorge are part of the Salida-Gunnison Volcanic Arc Transition zone of overlapping Yavapai and Mazatzal processes. MJD 3/2016 31 Ref: Abbott, Hoffman,
  32. 32. Geologic History of the Denver Area • A third stage set of igneous plutonic pulses occurred in the Arizona, New Mexico, and Colorado Area – 1.50 Bya This pulse did not occur in the Denver Area – 1.45 to 1.4 Bya This pulse occurred as the Silver Plume, Mount Evans, and Longs Peak Batholiths • Largely granite to granodiorite in composition • Berthoud Plutonic Suite (Berthoud Orogeny) MJD 10/2016 32 Ref: Hoffman,
  33. 33. Geologic History of the Denver Area • Iron Dike Intrusion – Dark-gray to black ferrogabbro; weathers dark brown to orange brown with prominent limonite stains along joint surfaces; very fine grained along dike margins, and medium grained in centers of thicker dike segments (as wide as 50 ft). Intruded 1,316 ± 50 Ma (Rb-Sr isochron; Braddock and Peterman, 1989). Iron Dike forms a narrow north-northwest trending swarm that can be traced almost continuously from eastern margin of Front Range near Boulder, across Estes Park quadrangle, and beyond into Medicine Bow Range to near Colorado-Wyoming State line, over a distance of about 95 mi. – Ferrogabbro composition indicates a deeper mantle source than all previous igneous intrusions. The cause of this intrusion is unclear. – Cool location to observe this: Near Boulder and near Estes Park MJD 3/2016 33 Ref: Kellog
  34. 34. • Grenville Orogeny Geologic History of the Denver Area 13Bya 4.5Bya 2.45Bya Big Bang Earth Formation Canadian Shield Forms 1.76Bya Yavapai Orogeny Precambrian Grenville Orogeny 1.0Bya Grenville Orogeny: Mountain building as a result of the Collision of many land masses forming the first supercontinent, Rodinia. MJD 3/2016 34 Ref: Abbott, Hoffman, Now
  35. 35. • Grenville Orogeny Geologic History of the Denver Area 13Bya 4.5Bya 2.45Bya Big Bang Earth Formation Canadian Shield Forms 1.76Bya Yavapai Orogeny Precambrian Grenville Orogeny 1.0Bya Immense collision forces may have resulted in fracturing the crust and causing rift zones internal to the continent MJD 3/2016 35 Ref: Abbott, Hoffman, Now
  36. 36. Geologic History of the Denver Area • Pikes Peak Batholith – 3 Intrusive Centers • Pikes Peak • Buffalo Park • Lost Park – Other Intrusive Centers may be buried – 7 satellite stocks of non granite igneous rock are associated. MJD 3/2016 36 Ref: Abbott, Epis
  37. 37. Geologic History of the Denver Area • Sandstone Dikes – Extremely unusual feature that occurs within the Pikes Peak Granite in more than one geographical location – Also occurs in biotite gneiss near Arapahoe Pass in the Indian Peaks Wilderness Area and is associated with the Arapahoe Pass Fault. – Explanations vary, but most likely fault induced fissures into which unconsolidated sand from aeolian sand dunes fell. • Likely occurred in the Precambrian between 1.0 Bya and 0.5 Bya. Possibly at the breakup of Rodinia (0.8 Bya). • Dunes or dune formation eroded during Precambrian time leaving no other trace of its existence. MJD 3/2016 37 Ref: Epis, Siddoway
  38. 38. Geologic History of the Denver Area • Sandstone Dikes (Very Unusual) – Cool Place: Highway 126 (Pine Valley Rd) Granite Granite Sandstone Dike MJD 3/2016 38
  39. 39. • Cambrian Period – Explosion of Multicellular Life – Marks the beginning of the Phanerozoic Eon / Paleozoic Era – Earth for the first time had an over abundance of oxygen which probably lead to the development of multicellular life Geologic History of the Denver Area 13Bya 4.5Bya 2.45Bya Big Bang Earth Formation Canadian Shield Forms 1.76Bya Yavapai Orogeny Precambrian Grenville Orogeny 1.0Bya Cambrian Period 0.54Bya Phanerozoic MJD 3/2016 39 Now
  40. 40. • Cambrian Period -> Ordovician Period – Started with no deposition and ended with flooding by shallow sea in Colorado • Upper Cambrian Sawatch formation marks the transgression of the sea. • Cool Place: Sawatch deposited on Pikes Peak Granite visible in Manitou Springs. Geologic History of the Denver Area MJD 3/2016 40 Ref: Blakey
  41. 41. • Ordovician Period -> Silurian Period – Shallow Sea followed by no deposition in Colorado. Geologic History of the Denver Area MJD 3/2016 41 Ref: Blakey
  42. 42. • Silurian Period -> Devonian Period – Shallow Sea transgression across Colorado. – Eurasian/African Plate encroaches NA plate. Geologic History of the Denver Area MJD 3/2016 42 Ref: Blakey
  43. 43. • Kimberlite Diatremes – Widespread clusters of deep mantle derived volcanic activity occurred in the West from Very late Precambrian through Devonian. – Source is at depths where pressures are great enough to form diamonds. – Volcanism was very violent ripping away wall rocks, some of which were entombed within the diatreme pipes themselves. – Captured wall rocks suggest Silurian/Devonian ages for diatremes near the CO/WY boarder. – Some diatremes including the one near Boulder are Late Precambrian or early Cambrian. Geologic History of the Denver Area MJD 3/2016 43 Ref: Abbott, Cole Coopersmith, Kellog
  44. 44. • Kimberlite Diatremes Geologic History of the Denver Area Economics of these diatremes: 0 to 100 carats per 100 tons. MJD 3/2016 44 Ref: Coopersmith
  45. 45. • Kimberlite Diatremes Geologic History of the Denver Area Cool Unusual Place near Denver: Boulder’s Green Mountain Diatreme MJD 3/2016 45 Ref: Abbott, Nesheim
  46. 46. • Devonian Period -> Mississippian Period – Shallow Sea still across Colorado. – Eurasian/African Plate encroaches NA plate Geologic History of the Denver Area MJD 3/2016 46 Ref: Blakey
  47. 47. • Mississippian -> Pennsylvanian Period Geologic History of the Denver Area Ancestral Rockies Appalachians Atlas Mtns MJD 3/2016 47 Ref: Blakey
  48. 48. Geologic History of the Denver Area • The Great Colorado Unconformity – Uplift of Ancestral Rockies eroded all previously deposited Sedimentary rocks – Alluvial deposits (Fountain Formation) on Precambrian – Cool Place: Red Rocks Amphitheater MJD 3/2016 48
  49. 49. • Pennsylvanian Period -> Permian Period Geologic History of the Denver Area MJD 3/2016 49 Ref: Blakey
  50. 50. • Permian Period – Supercontinent Pangea – Continued erosion of Ancestral Rockies. – Large scale wind blown Sand dunes and location dependent fluvial (stream/river) deposits. – Cool Places: Lyons Formation in Morrison (contains very large desiccation cracks. Lyons Formation in Red Rock Canyon Open Space Park, Manitou Springs (contains large dune crossbedding, also SS quarry for building stone ). – Permian Period ends with the largest extinction event in geologic history. Geologic History of the Denver Area MJD 3/2016 50
  51. 51. • Permian Period – Mud cracks (Matthews) or freezing/thawing cracks (Abbott) in Lyons formation in Morrison city limits. Geologic History of the Denver Area MJD 3/2016 51 Ref: Matthews, Abbott
  52. 52. • Triassic Period – No trace of Ancestral Rockies remain – Lykins Formation • Low lying mudflats with interfingering marine limestones • Red iron oxidation suggests arid to semi arid conditions • Cool places: Within Morrison city limits, South Valley Park, and above NCAR in Boulder • Limestones contain stromatolite trace fossils. Geologic History of the Denver Area MJD 3/2016 52
  53. 53. • Jurassic Period – Breakup of supercontinent Pangea – Morrison Formation • Ancient river channel and flood plains deposits • Red iron oxidation and teal iron reduction in the flood plain / ancient soils • Dinosaurs • Cool place: Dinosaur Ridge (bone site and track site) Geologic History of the Denver Area MJD 3/2016 53
  54. 54. • Jurassic Period – Morrison Formation • Cross Section of current ripples at Dinosaur Ridge Geologic History of the Denver Area MJD 3/2016 54
  55. 55. • Cretaceous Period – Dakota Formation • Cyclical occurrences of ancient river channel deposits progressing into tidal flat, shoreface and marine deposits. • Dinosaurs • Cool place: Dinosaur Ridge – Track site – dinosaur and crocodile – Fossil plant material in channel sands – Small burrows in tidal flat and shallow marine deposits – Volcanic ash deposits • Cool Place: Eldorado Canyon near Boulder – Tidal Flat and shallow marine / delta deposits Geologic History of the Denver Area MJD 3/2016 55
  56. 56. • Cretaceous Period – Dakota Formation Geologic History of the Denver Area Track site MJD 3/2016 56
  57. 57. • Cretaceous Period – Dakota Formation Geologic History of the Denver Area U Shaped burrows in Tidal Flat MJD 3/2016 57
  58. 58. • Cretaceous Period – Cretaceous Interior Seaway • Over 5000 feet of marine deposits – Benton, Niabrara, and Pierre Formations • Cool place: – Dinosaur Ridge – Benton shale – City of Morrison (along bike trail under C470) – Benton & Niabrara – NCAR (Boulder) and Red Canyon Open Space (CO Sprgs) – Niabrara – Rooney Road – Pierre Geologic History of the Denver Area MJD 3/2016 58
  59. 59. • Cretaceous Period – Cretaceous Interior Seaway Geologic History of the Denver Area Seaway Deposits MJD 3/2016 59
  60. 60. • Cretaceous Period – Cretaceous Interior Seaway Geologic History of the Denver Area MJD 11/2016 60 Ref: Blakey, Wikipedia
  61. 61. • Cretaceous Period – Uplift: Retreat of the Seaway and rise of the Rockies • Compression in the North American plate caused regional uplift resulting in regression of the sea. • Further compression caused major thrust faulting – Faults extended down into the basement crystalline rocks – This episode is called the Laramide Orogeny • Cool place: – Rooney Road – Fox Hills Formation Delta deposits – Fossil Trace Golden and CSM Golden – dinosaur tracks in Laramie Formation – Bear Creek Reservoir Park (Lakewood) and Marshall Open Space (Boulder) - Fox Hills and Laramie Formations: beach and swamp (coal) Geologic History of the Denver Area MJD 3/2016 61
  62. 62. • Cretaceous Period Geologic History of the Denver Area MJD 3/2016 62 Ref: Abbott
  63. 63. • Late Cretaceous Period Geologic History of the Denver Area MJD 3/2016 63 Ref: Abbott
  64. 64. • Late Cretaceous Period – KT Boundary • Most famous extinction event of all (extinction of the dinosaurs) • Cool Place: South Table Mountain at about 70 meters below lava flows on SE side. KT boundary determined from fossil pollens (clay layer itself is not preserved) • Cool Place: Clay layer outcrops in Bijou Creek Geologic History of the Denver Area MJD 11/2016 64 Ref: Kellog, et. al. , 2004
  65. 65. • Paleocene Epoch – Golden Fault was still active – Erosion continued into the crystalline basement rocks and formed a rough but gentle sloping eastward plane called the Rocky Mountain Erosion Surface (parts still observable today) – Front Range Volcanoes emerged creating many lava flows. – Most of the lava flows eroded and redeposited as stream bed conglomerates of the Denver Formation. Occurrences of fossil plant material. Cool Place: lower half of Green Mountain. Geologic History of the Denver Area MJD 3/2016 65
  66. 66. • Paleocene Epoch Geologic History of the Denver Area MJD 3/2016 66 Ref: Abbott
  67. 67. • Paleocene Epoch – Cool Place: North and South Table Mountains • 3 lava flows on North Table Mountain • 2 lava flows on South Table Mountain • Composition of the lava is called Shoshonite (a variation of Latite). Mixture of plagioclase and orthoclase feldspars. • Contains mineralization – Zeolite Group: thomsonite, anaclime, chabazite, aragonite, and others • Lava source was Ralston Dike located a few miles north of North Table Mountain. Geologic History of the Denver Area MJD 3/2016 67 Ref: Drewes 2006, Pearl
  68. 68. • Paleocene Epoch Geologic History of the Denver Area MJD 3/2016 68 Ref: Abbott
  69. 69. • Eocene Epoch (58 – 37 mya) – Front Range Volcanoes went extinct. – Golden Fault went dormant. – Major erosion period buries the mountains in their own debris and removes steep slopes. – Cool Place: Green Mountain Conglomerate (contains fossil plant and wood material) on Green Mountain. Geologic History of the Denver Area MJD 3/2016 69
  70. 70. • Eocene Epoch Geologic History of the Denver Area (Saprolite – intense chemical weathering of gneiss. Current top of Lookout Mountain) MJD 3/2016 70 Ref: Abbott
  71. 71. • Eocene Epoch – Ignimbrite Flare-up • One of the most extensive episodes of high-silica volcanism (high explosive) in the world • 6 of the 40 worlds largest eruptions of all time anywhere in the world occurred in Colorado at this time • Wall Mountain Tuff was the opening volley with an extremely large pyroclastic flow. – Volcanic Source 65 miles to the west near Mt. Princeton – https://www.youtube.com/watch?v=Cvjwt9nnwXY (example) • Cool place: Wall Mountain Tuff in Rhyolite Park in Castle Rock. Most of the tuff has been quarried for building material but some still remains in place. Geologic History of the Denver Area MJD 3/2016 71 Ref: Abbott
  72. 72. • Eocene Epoch – Wall Mountain Tuff – Hot incandescent cloud of ash and gas raced across central Colorado to the vicinity of Castle Rock in about an hour consuming everything in its path. As the huge volume of material erupted, the surface foundered into the magma chamber. Geologic History of the Denver Area MJD 3/2016 72 Ref: Matthews
  73. 73. • Eocene Epoch – Wall Mountain Tuff Geologic History of the Denver Area Topography was different than it is today MJD 3/2016 73 Ref: Abbott
  74. 74. • Eocene Epoch – Massive Flooding - Castle Rock Conglomerate • Extensive flooding brought large stones from as far away as 46 miles (pieces from Coal Creek Quartzite) • Contains blocks of Wall Mountain Tuff, thus younger than the tuff itself. • Cool place: Rock Park in Castle Rock and Castlewood Canyon State Park Geologic History of the Denver Area MJD 3/2016 74 Ref: Abbott
  75. 75. • Eocene Epoch – Castle Rock Conglomerate • Massive flooding carves canyon in Wall Mountain Tuff. Geologic History of the Denver Area Topography was different than it is today MJD 3/2016 75 Ref: Abbott
  76. 76. • Eocene Epoch – Castle Rock Conglomerate • Massive flooding brings material from as far away as Boulder CO. Geologic History of the Denver Area Topography was different than it is today MJD 3/2016 76 Ref: Abbott
  77. 77. • Eocene Epoch – Florissant Formation • Guffey Volcanic eruptions – After Wall Mountain – Buries leaves, insects, and fish in ash • Lahar ( volcanic mud and debris flow) buries Sequoia redwood forest. • Cool place: Florissant National Monument Geologic History of the Denver Area MJD 3/2016 77 Ref: Abbott
  78. 78. • Oligocene, Miocene, and Pliocene Epochs – Continued regional uplift to 5000 ft – Erosion: Incision of canyons and valleys in the mountains Geologic History of the Denver Area MJD 3/2016 78 Ref: Abbott
  79. 79. • Pleistocene Epoch – Cool Place: Mount Morrison Slide in Matthews Winters Park. Massive landslide deposit when the valley floor was not incised as deep as it is today. Geologic History of the Denver Area MJD 3/2016 79 Ref: Drewes 2005
  80. 80. • Pleistocene Epoch – Glaciation in the mountains – Cool Place: Valleys of Rocky Mountain National Park – Cool Place: Lamb Spring (Littleton, CO); Pleistocene animal remains of mammoths, camels, horses, sloths, llamas and wolves. ~ 13Kya Geologic History of the Denver Area MJD 3/2016 80 Ref: Web Site
  81. 81. • Modern Times – Earliest human inhabitants ~8400 years ago as evidenced by spear points and bison bones at Lamb Spring (Littleton, CO) – Magic Mountain Archeological Site (Apex Open Space) ~ 5000 years human presence – Plains Indians – 1858 first white settlement in Denver – 1970 skyscraper boom Geologic History of the Denver Area MJD 3/2016 81
  82. 82. Geologic History of the Denver Area • References Abbott,A. and Cook,T. 2012, Geology Underfoot Along Colorado’s Front Range. Mountain Press Publishing Co, Missoula, MT. Blakey, Ron, Paleogeography and Geologic Evolution of North America: https://www2.nau.edu/rcb7/nam.html Cole, J.C., and Braddock, W.A., 2009, Geologic map of the Estes Park 30’ x 60’ quadrangle, north-central Colorado: USGS Scientific Investigations Map 3039, 1 sheet, scale 1:100,000. Coopersmith, H., Mitchell, R., Hausel, W., 2003, Kimberlites and Lamproites of Colorado and Wyoming, USA. Guidebook Prepared for the VIIIth International Kimberlite Conference, Colorado and Wyoming Field Trip 16-21 June2003, Geological Survey of Canada, Ottawa, Ontario. Drewes, H., Townrow, J., 2005, Trailwalkers Guide To The Dinosaur Ridge, Red Rocks And Green Mountain Area, Second Edition, Friends of Dinosaur Ridge, Morrison, CO Drewes, H., 2006, Table Mountain Shoshonite Porphyry Lava Flows and Their Vents, Golden, Colorado, Scientific Investigations Report 2006-5242, US Geological Survey Epis, R. and Weimer, R., 1976, Professional Contributions of Colorado School of Mines; Studies in Colorado Field Geology. Colorado School of Mines, Golden, Colorado. Hoffman,P. 1988, United Plates of America, The Birth Of A Craton: Early Proterozoic Assembly and Growth of Laurentia. Annual Review of Earth Planetary Sciences, Vol 16, Palo Alto, CA, Annual Reviews, Inc, p. 543-603. Jones,D. et at. 2010, New Models for Paleoproterozoic orogenesis in the Cheyenne belt region: Evidence from the geology and U-Pb geochronology of the Big Creek Gneiss, southeastern Wyoming. GSA Bulletin Vol 122; no. 11/12. Kellog,K., Bryant,B., and Reed,J., 2004, The Colorado Front Range-Anatomy of a Laramid Uplift, Geological Society of America Field Guide 5. Kellog,K., et al, 2008, Geologic Map of the Denver West 30’ x 60’ Quadrangle, North Central Colorado: USGS Scientific Investigations Map 3000, 1 sheet MJD 3/2016 82
  83. 83. Geologic History of the Denver Area • References Knight,S.H., 1968, Precambrian staromatolite bioherms and reefs in the lower half of the Nash Formation, Medicine Bow Mountains, Wyoming: University of Wyoming Contributions to Geology, University of Wyoming, v. 7, no. 2. Matthews, Vincent, 2009, Messages in Stone Colorado’s Colorful Geology, Colorado Geological Survey, Denver , Colorado, Second Edition. Nesheim, T., 2013, Recent Diamond Exploration In Eastern North Dakota. North Dakota Department of Mineral Resources Geo News, Vol 40, No. 1, January 2013. Pearl, R., 1972, Colorado Gem Trails and Mineral Guide, Sage Swallow Press, Athens, Ohio. Siddoway, C. and Gehrels, G., 2014, Basement-hosted sandstone injectites of Colorado: A vestige of the Neoproterozoic revealed through detrital zircon provenance analysis. GSA Abstract. Snoke, Art, August 17, 2013, RMAG Snowy Range, Medicine Bow Mountains, Wyoming Field Trip. University of Wyoming Unpublished Paper. Web Site: Lamb Spring Archeological Preserve: http://www.lambspring.org/ Wikipedia, online encyclopedia: https://en.wikipedia.org/wiki/Radiometric_dating Wikipedia, online encyclopedia: https://en.wikipedia.org/wiki/Supernova Wikipedia, online encyclopedia: https://en.wikipedia.org/wiki/Western_Interior_Seaway Weimer,R. ,et al. 2011, A Guide to Mines Geology Trail. Geology Museum Special Publication No 3. MJD 3/2016 83
  84. 84. Geologic History of the Denver Area • Field Trip: • Bring: – Water – Hiking food – Magnifying glass – Camera – Sun Protection (sunscreen, hat, ect) MJD 3/2016 84
  85. 85. Geologic History of Denver – Locations: • Chamberlain Observatory • Bioherms – Medicine Bow Mtns • Iron Dike* - Boulder • SS Dikes – Pine Junction • Sawatch – Manitou Spgs • Kimberlite - Green Mountain Boulder • Red Rocks Amphitheater – Fountain FM • Lyons: Desiccation Morrison, quarry CO Sprgs • Lykins: Morrison, South Valley Park, NCAR • Eldorado Canyon – Fountain – Dakota FMs MJD 3/2016 85
  86. 86. Geologic History of Denver – Locations: • Dinosaur Ridge – Morrison FM and Dakota FM • Benton FM – Morrison • Niabrara – Morrison, Bear Creek Park, NCAR, Red Canyon Open Space • Pierre – Rooney Road, • Fox Hill, Laramie – CSM, Fossil Trace, Rooney Road, Bear Creek Park, Marshall Open Space • Denver Formation – Green Mountain, N and S Table Mountains • KT – S Table Mountain, Bijou Creek* MJD 3/2016 86
  87. 87. Geologic History of Denver – Locations: • Paleocene – N and S Table Mountains • Wall Mountain Tuff – Castle Rock • Castle Rock Conglomerate – Castle Rock • Florissant • Green Mountain plant and wood material • Morrison Slide • Rocky Mountain National Park • Lamb Spring* • Apex Site MJD 3/2016 87 * Author has not been to this location as of publication

×