The major structural features of the northeast part of the Rio Puerco fault zone are (1) north- to northwest-trending folds, (2) northeast-trending normal faults, and (3) north-trending normal faults. These structures formed in response to an older north-oriented shear couple and a younger east-west-oriented tension. Laramide orogenic movements of late Paleocene through Eocene age resulted from a north-trending, right-shift force couple related to northeast shift of the Colorado Plateau. The folds and the northeast-trending normal faults formed in response to the right-shift couple, and the faults are interpreted as tensional fractures that developed at 45° to the trend of the couple. Miocene to Holocene tectonism is dominated by north-trending, east-dipping normal faults related to the development of the Rio Grande rift. Many southeast-dipping normal faults of Laramide origin were rejuvenated during Miocene and younger rifting.

This content is PDF only. Please click on the PDF icon to access.

First Page Preview

First page PDF preview
You do not have access to this content, please speak to your institutional administrator if you feel you should have access.