•   Paleogene chilling of  polar deep waters leads to Neogene glaciation

 
•   Mountain building along Western America

 
•   Abundant outcrops of poorly consolidated rocks

 
•   ANTARCTIC REGION: circumpolar current forms

 
•   ARCTIC REGION:  Bering land bridge = migration

LATE NEOGENE CLIMATE CHANGE
 

• Widespread unconformity = sea level dropped = glaciation

Several pulses of warming and cooling through the last Ice Age
 

•   Glacial maxima characteristics

•    Deserts expand
•    Pluvial lakes
•    Rain forests fragmented
•    Primates isolated
•    Steeper gradient

•   Glacial minima (like today)

•   Glaciation Cause:

REGIONAL GEOLOGIC EVENTS

Gulf Coast:
Mississippi Embayment: 5 km of Paleogene delta sediment = oil traps

Western Atlantic ocean: quiescent.
                                                      Chesapeake group.
                                                      siliciclastic sequence
                                                      river erosion   valleys and ridges

Formation of the Caribbean Sea: Atlantic subduction

Western North America
         Laramide orogeny (Paleocene)
                                             shallow angle
                                             block uplift from Montana to Mexico
                                             Green River formation     lakes
                                                                                     Oil shale
                                              low sulfur coal (Eocene)

 Hot spot in Yellowstone:
                                             Eocene: volcanism,
                                             Miocene: leveled => 20 successive forests buried
 
 
 
 
 

Physiographic Provinces of the American West
 

•  Rocky Mountains

•  Colorado Plateau

•  Basin and Range

•  Sierra Nevada

•  Great Valley

•  Coast Range

 

 

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