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1. Parks Formed by Stream Erosion and Weathering(part 2) BRYCE CANYON
ARCHES
MESA VERDE
3. Stratigraphy of Colorado Plateau
From Geology of the Colorado Plateau, 1999, Annabelle Foos, Geology Department, University of Akron Bryce Canyon
4. Native American History Basket Maker Culture
Later, Pueblo Culture
~ 1200 AD Paiute tribes farmed and hunted, no settlement
5. Human History (con’t) 1776, Escalente & Dominquez Expedition
1850’s trappers and Mormons in area
1871, John Wesley Powell
1871-76 Wheeler Survey Expedition
1874-1891 Mormon Settlers
1905 area became National Forest
1923 NM
1928 NP
6. Geologic Features Stream Erosion
Structural features
Differential Weathering
7. Horseshoe Shaped BasinThree regions in park
8. Structural Features Uplift creates cracks & joints –
control features such as pinnacles, The Wall, arches, windows, and natural bridges – similar to Zion
9. Differential Weathering Joints, differential erosion, frost action, oxidation to give colors
10. Geologic History - Stratigraphy Table 3.2, p. 53
11. Geologic History – Mz – Cretaceous – Marine to River
Cz – Eocene – Claron formation
Inland lake – changed size, different rocks
Fossils mammals, clams, snails, turtles, plants
Oligocene – volcanic rocks
Miocene – uplift and faulting
Leads to erosion and cooler climate –
Quaternary - glaciers
13. Human History Early Native Americans used area for chalcedony for tools
no known settlements
1800’s – Trappers and Mormons
1929 Arches NM
1971 Arches NP
14. Geologic Features Stream Erosion
Differential Weathering
Structural Features
The Arches
Salt Anticline
15. Structural Features – Joints Similar to previous parks
16. Fins
17. Arches
18. Pinnacles and Balanced Rocks
19. Salt Anticline
20. Geologic HistorySimilar to Zion Pennsylvanian – near shore –
evaporites – salt and gypsum
Permian – Cutler Fm. – shallow sea
21. Mesozoic History Triassic – similar to Zion
Arid, near shore and shallow seas
Entrada SS –>
Navajo Sandstone ->
22. Geologic History Cretaceous (End of Mz) – deposition then erosion
Lt. Miocene (~13mya) block faulting
Tilted
Uplifted – salt graben forms, jointing
24. History AD 1-750 Basket Maker Culture
AD 750-1300 Classic Pueblo
Mid 1700’s Spanish traders, named mesa
1776 Escalante camped in area
1888 dwellings discovered by local rancher
1900 Colorado Cliff Dwellings Association
1906 TR established Mesa Verde NP
25. Possible scene from Spruce Tree House, ~1250
26. Geologic Features The Cuesta
Erosional Features
Weathering
Water supply
The Dwellings
27. Cuesta
28. Geologic Features The Cuesta
Erosional Features
Mesa
Canyons
Weathering
Water supply
The Dwellings
29. Erosional Features - Mesa Point Lookout Sandstone ->
Mancos Shale ->
30. Erosional Features - Canyons
31. Geologic Features – The Dwellings
32. Geologic History Cretaceous marine rocks
Cenozoic tectonics
33. Point Lookout sandstone above Mancos Formation (shales). (Photo by David B. Hacker)
34. Cretaceous Cliff House Sandstone