Cenozoic Geology
Cenozoic Geology: Learning Objectives
The Cenozoic (65 mya to present) is divided into 2 periods and 7 epochs.
Tertiary: 65 mya - 2 mya
Quarternary: 2 mya - present
Eocene global map
Paleocene paleogeographic map
Eocene paleogeographic map
I) Craton:
Stable, some erosion. In the Late Cenozoic (Pliestocene) glaciation will affect this area.
II) Eastern Margin:
The Appalachians continue to erode building the Continental shelf and the Coastal Plain.
The Atlantic continues to widens and is widening today.
Florida forms from the buildup of carbonate deposits.
III) Southern Margin:
Sediments eroding off of the Rockies, the Appalachians and the shield form a VERY thick sediment wedge in the southern margin. Eight transgression/regression events occur.
IV) Western Margin:
This margin will be discussed as distinct regions. Refer to the map given in class for the location of each of these regions.
1) Rockies and High Plains:
Basin and Range Province:
This area was folded and overthrust in the Mesozoic. Beginning in the Miocene this area underwent normal faulting as the result of tensional tectonics. Block fault mountains and downdropped basins resulted. These short mountains shed sediments into the valleys, some valleys contained lakes and evaporite deposits.
3) Colorado Plateau:
The Colorado Plateau consists of a piece of the crust that has remained undeformed since Paleozoic time. It is composed of layers of flat lying sedimentary rocks of Paleozoic and Mesozoic age. During the Pliocene the plateau was uplifted and tilted upward along its northern edge. Large faults as well as volcanoes formed around the edges of the plateau. Uplift caused downward erosion by streams forming the Grand Canyon and the
Goosenecks of the San Juan
(entrenched meanders).
4) Columbia Plateau:
In the Late Cenozoic flood basalts covered 31,000 square miles of this region to a depth of up to 9,000 ft. West of the Columbia Plateau the Cascade Range forms as a result of subduction along the Pacific Coast. The Cascade volcanoes are still active today.
5) Sierra Nevada and California:
During the Mesozoic the Nevadian orogeny uplifted and folded this region, batholiths were emplaced. In the Pliocene the Sierra Nevadas were uplifted on their eastern edge 12,000 ft and tilted westward.
6) West Coast:
Subduction of the Farrallon Plate under North America (forms Cascade Range). Coastal ranges formed from compression and faulting. San Andreas Fault becomes active.
Other:
South America: a subduction zone forms along its western edge forming the Andes
Africa: closes toward Europe in a scissor fashion forming the Pyrenees, Alps and Atlas Mountains.
Australia and Antarctica separate.
India: moves toward Asia forming the Himalayas.
