Oxaya anticline
The Oxaya anticline is a large north-south aligned anticline and buckle in the Chilean Andes west of the Altiplano Plateau. The anticline is about 60 km long. The anticline constitutes a watershed for smaller streams but is crossed along its short axis by the larger Azapa and Lluta rivers. A series of normal faults and associated grabens exists on top of the Oxaya anticline. These faults have the same NNW-SSE orientation as the long axis of the anticline. The Oxaya anticline developed from the Miocene onwards as a direct or indirect response to east-west shortening of the South American plate in the context of the Andean orogeny.[1] Three models have been proposed to explain the anticline:[1]
- That it is a buckle fold with no associated shallow fault
- That it is the result of movement along a west-vergent thrust fault system or fault-propagation fold
- That it is a block rotated by a listric fault
The formations deformed by the anticline include Azapa, Huaylas and Oxaya Formation.[1]
References
- Zeilinger, Gerold; Schlunegger, Fritz; Simpson, Guy (2005). "The Oxaya anticline (northern Chile): a buckle enhanced by river incision?". Terra Nova (17): 368–375.