TY  - JOUR
A1  - Schildgen, Taylor F.
A1  - Hodges, Kip V.
A1  - Whipple, Kelin X.
A1  - Pringle, Malcolm S.
A1  - van Soest, Matthijs
A1  - Cornell, Katrina
T1  - Late Cenozoic structural and tectonic development of the western margin of the central Andean Plateau in southwest Peru
N2  - Structural and thermochronologic studies of the western margin of the central Andean Plateau show changing styles of deformation through time that give insights into tectonic evolution. In southwest Peru, uplift of the plateau proceeded in several distinct phases. First, NW striking, NE dipping reverse faults accommodated uplift prior to similar to 14-16 Ma. Subsequent uplift of the plateau relative to the piedmont (between the plateau and the Pacific Ocean) occurred between similar to 14 and 2.2 Ma and was accommodated by NW striking, SW dipping normal faults and subparallel monoclinal folds. The youngest phase of uplift affected the piedmont region and the plateau margin as a coherent block. Although the uplift magnitude associated with phase 1 is unknown, phases 2 and 3 resulted in at least 2.4-3.0 km of uplift. Up to 1 km of this may have occurred during phase 3. Geodynamic processes occurring in both the continental interior and the subduction zone likely contributed to uplift.
Y1  - 2009
UR  - http://www.agu.org/journals/tc/
U6  - https://doi.org/10.1029/2008tc002403
SN  - 0278-7407
ER  - 
TY  - JOUR
A1  - Schildgen, Taylor F.
A1  - Ehlers, Todd
A1  - Whipp, David M.
A1  - van Soest, Matthijs C.
A1  - Whipple, Kelin X.
A1  - Hodges, Kip V.
T1  - Quantifying canyon incision and Andean Plateau surface uplift, southwest Peru : a thermochronometer and numerical modeling approach
N2  - Apatite and zircon (U-Th)/He ages from Ocona canyon at the western margin of the Central Andean plateau record rock cooling histories induced by a major phase of canyon incision. We quantify the timing and magnitude of incision by integrating previously published ages from the valley bottom with 19 new sample ages from four valley wall transects. Interpretation of the incision history from cooling ages is complicated by a southwest to northeast increase in temperatures at the base of the crust due to subduction and volcanism. Furthermore, the large magnitude of incision leads to additional three-dimensional variations in the thermal field. We address these complications with finite element thermal and thermochronometer age prediction models to quantify the range of topographic evolution scenarios consistent with observed cooling ages. Comparison of 275 model simulations to observed cooling ages and regional heat flow determinations identify a best fit history with <= 0.2 km of incision in the forearc region prior to similar to 14 Ma and up to 3.0 km of incision starting between 7 and 11 Ma. Incision starting at 7 Ma requires incision to end by similar to 5.5 to 6 Ma. However, a 2.2 Ma age on a volcanic flow on the current valley floor and 5 Ma gravels on the uplifted piedmont surface together suggest that incision ended during the time span between 2.2 and 5 Ma. These additional constraints for incision end time lead to a range of best fit incision onset times between 8 and 11 Ma, which must coincide with or postdate surface uplift.
Y1  - 2009
UR  - http://www.agu.org/journals/jf/
U6  - https://doi.org/10.1029/2009jf001305
SN  - 0148-0227
ER  -