1. Harry Williams, Historical Geology
CENOZOIC GEOLOGY.
EARLY CENOZOIC: ( MYBP):
Introduction: Much of the landscape as it appears today resulted from a number of "land-forming" events of the early Cenozoic.
Harry Williams, Historical Geology

2. Harry Williams, Historical Geology
Paleogene Paleogeography.
Harry Williams, Historical Geology

3. Harry Williams, Historical Geology
Appalachians and
Coastal Plains
Rockies and Great Plains
Harry Williams, Historical Geology

4. Harry Williams, Historical Geology
Gulf Coast Main area of marine transgressions and regressions during Cenozoic, this, combined with pronounced subsidence, resulted in about m of Paleogene/Neogene sediments underlying the Gulf Coast
Harry Williams, Historical Geology

5. Harry Williams, Historical Geology
East Coast
Relatively quite during the Cenozoic. The erosion of the Appalachians continued, producing subdued, rounded mountains (characteristic of ancient mountains). The coastal plain and continental shelf continued to be built from clastics in the northeast and carbonates in the southeast (Florida).
Harry Williams, Historical Geology

6. Harry Williams, Historical Geology
Low, rounded, vegetated mountain ridges in the Appalachians.
Harry Williams, Historical Geology

7. Harry Williams, Historical Geology
East coast coastal plain – dominated by coastal processes and landforms e.g. spits, barriers, beaches, marshes, etc.
Cape Fear
Harry Williams, Historical Geology

8. Harry Williams, Historical Geology
Barrier Island
Mississippi delta
Harry Williams, Historical Geology

9. Harry Williams, Historical Geology
Bahama Banks
Harry Williams, Historical Geology

10. Harry Williams, Historical Geology
Rockies Continuing uplift and erosion shaped the Rockies into rugged, sharp peaks (characteristic of youthful mountains). In some areas, large fault blocks were pushed up to form mountain ranges, such as the Tetons of Wyoming. Clastics from the erosion spread eastward, forming the Great Plains.
Tetons.
Harry Williams, Historical Geology

11. Harry Williams, Historical Geology
West Coast Tectonics
Subduction down much of the west coast stopped in the Cenozoic, as the Farallon Plate* and the east Pacific Rise* were “swallowed” by the subduction zone. Instead, a transform fault developed about 10 million years ago. Subduction continued to the north (Juan de Fuca plate) and the south (Cocos plate). A number of features are related to these plate movements…
* 1st time we’ve covered these.
Harry Williams, Historical Geology

12. Harry Williams, Historical Geology
San Andreas Fault
Cascades
Columbia Plateau
Basin and Range
Colorado Plateau
Harry Williams, Historical Geology

13. Harry Williams, Historical Geology
San Andreas Fault
Harry Williams, Historical Geology

14. Harry Williams, Historical Geology
Mt. St. Helens, 1980.
The Cascades - volcanic arc.
Harry Williams, Historical Geology

15. Harry Williams, Historical Geology
Columbia Plateau - flood basalts resulting from a hot spot.
Harry Williams, Historical Geology

16. Harry Williams, Historical Geology
Basin And Range Province Tensional forces developed in large areas of Nevada, Arizona, New Mexico and South California during the Cenozoic, probably resulting from the change from subduction to transform fault along the craton margin and heat flow from subduction. The result was basin and range topography, characterized by normal faults, tilted fault blocks, grabens and horsts:
Harry Williams, Historical Geology

17. Harry Williams, Historical Geology
Range
Basin
Death Valley, California.
Harry Williams, Historical Geology

18. Harry Williams, Historical Geology
Graben and horst.
Harry Williams, Historical Geology

19. Harry Williams, Historical Geology
Tilted fault blocks.
Harry Williams, Historical Geology

20. Harry Williams, Historical Geology
Colorado Plateau
A large block of crust in the southwest remained relatively undeformed, but was uplifted during the Cenozoic (5 -10 mybp), forming the Colorado Plateau. Streams cut down into the plateau as it was lifted up, forming deep canyons, including the Grand Canyon (2600 m deep). Magma was released from faults surrounding the uplifted plateau.
Harry Williams, Historical Geology

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Grand Canyon.
Harry Williams, Historical Geology

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Plateaus, mesas, buttes and pinnacles formed by stream erosion of uplifted strata.
Harry Williams, Historical Geology

23. Harry Williams, Historical Geology
Tethys Seaway
Closure of the Tethys Seaway was completed during the Cenozoic. Africa collided with Europe about 40 million years ago forming the PYRENEES, between France and Spain, and the ATLAS MOUNTAINS of northwest Africa. As Africa swung around, the collision spread eastward, forming the ALPS of southern Europe. Areas of the Alps are still undergoing periodic uplift today (the collision continues). Further east, India collided with Asia about 10 million years ago, forming the HIMALAYAS (the top of Mt. Everest is marine limestone); these mountains are also continuing to rise – frequent earthquakes in India/China attest to the continuing movement.
These orogenies created a long linear zone of mountains running east – west across Europe and Asia.
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25. Harry Williams, Historical Geology

26. Late Cenozoic. QUATERNARY PERIOD
Last 1.8 million years?
Distinguished by ice ages (Pleistocene epoch).
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27. At present, ice covers about 10% of the land surface, whereas at its maximum extent during the Pleistocene it covered about 30%.
Ice cover in the northern hemisphere about 15,000 years ago.
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28. Pleistocene glaciation is important since many areas glaciated in the Pleistocene are still dominated by glacial landforms today, even 10,000 years after the last Ice Age ended. The reason for this is that glaciers are capable of massive erosion and deposition and leave a long-lasting imprint on the local geomorphology. If you visit the northern states, or other glaciated regions, the only way to understand the local landscape is to recognize that these are glacial landscapes.
So, the significance of the Quaternary period is not a record of bedrock formed during the period (as is the case for all the other periods we’ve looked at), it’s the geomorphology (surface landforms) that developed during the Quaternary, particularly glacial landforms.
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29. In North America, two distinct types of glaciation occurred:
ALPINE GLACIATION, characterized by valley glaciers, in mountainous areas of the western U.S.; and CONTINENTAL GLACIATION, characterized by large unconfined ice sheets, over much of Canada and the northern states.
ALPINE GLACIATION
CONTINENTAL GLACIATION
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30. Landforms of Alpine Glaciation
EROSION is the dominant process in glaciated mountainous regions. The glaciers are confined to pre-existing steep valleys and tend to erode vertically. Wide U-shaped glacial troughs, hanging valleys, horns, cirques, aretes and truncated spurs are the result.
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31. hills mountains cliffs ridges Harry Williams, Historical Geology31

32. Landforms of Continental Glaciation.
Extent of glacial deposits from Pleistocene glaciations in the northern midwest. The last large glaciation was the Wisconsin. The Illinoian is an older glaciation that extended further south.
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33. DEPOSITION is dominant in lowland areas at the margins of continental glaciers - the northern states in North America. This is where debris carried in the ice is released as the ice melts. Further back from the ice front, (mainly in Canada) erosion can occur by SCOURING of the surface by debris (rocks) carried at the base of the ice. General scouring of the surface removed much topsoil from these areas, which is slow to recover due to the cold climates. Scouring also creates small grooves or striations or lager troughs aligned with the direction of ice flow; many larger troughs filled with water to become lakes.
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34. Canada Shield lakes. Harry Williams, Historical Geology34

35. Much of the landscape of the northern mid-west is dominated by depositional landforms. Deposition can occur directly from the ice - erratics, ground moraine, drumlins, end moraines - or from meltwater (mainly gravel, sand, mud) in the form of lake deposits, outwash (melt-water stream) deposits and eskers (sub-glacial melt-water deposits).
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36. Ice-marginal areas Harry Williams, Historical Geology36

37. Areas of ground moraine usually are not great for farming (boulders, water-logging, hummocky). They can be used for dairy farming e.g. Wisconsin.
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38. Erratics are common in ground moraine regions (this one is in Manitoba above the tree line). Erratics provide a clue to the source of ice.
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39. Ice flow
Drumlin, Alberta. Drumlins are formed from moraine that is pushed up into a hill by over-riding ice and then “streamlined” by the ice flow. They “point” in the direction of former ice flow.
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40. End moraine forming on Baffin Island
End moraine forming on Baffin Island. Debris carried by the ice piles up at the front of the ice sheet (where melting occurs).
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41. Esker - Manitoba. These are meltwater deposits laid down in a tunnel under the ice. The sediment is usually well-sorted sand and gravel.
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42. Outwash is sand and gravel deposited by meltwater streams that form in the summer. These streams are typically braided and create wide outwash plains. Outwash can extend 10’s of miles beyond the margin of an ice sheet. Outwash sediment has the character of alluvium (well-sorted, stratified).
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43. Bedrock ridge Outwash plain
Outwash plains are great for farming. They are flat, well-drained and fertile. This one is in Quebec.
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44. Harry Williams, Historical Geology
Summary: glaciers and ice sheets cause massive erosion and deposition. They create long-lasting erosional and depositional landforms. Glacial features dominate landscapes in the northern states and Canada, even though they were formed more than 10,000 years ago. In mountainous regions, glaciers are confined to valleys, concentrating their erosion. Consequently, EROSIONAL landforms dominate - there is relatively little deposition and few depositional features. In lowland regions, large unconfined ice sheets cause general scouring of the surface, while DEPOSITIONAL features dominate marginal areas (near the ice front). Deposition can be directly from the ice (ice-contact deposits, including ground moraine, drumlins, end moraine and eskers) or can be meltwater deposits (outwash plains) extending beyond the ice limits.
Harry Williams, Historical Geology