Uplift of the western margin of the Andean plateau revealed from canyon incision history, southern Peru

Taylor F. Schildgen; Kip Hodges; Peter W. Whipple; Peter W. Reiners; Malcolm S. Pringle

doi:10.1130/G23532A.1

Uplift of the western margin of the Andean plateau revealed from canyon incision history, southern Peru

Taylor F. Schildgen, Kip Hodges, Peter W. Whipple, Peter W. Reiners, Malcolm S. Pringle

Earth and Space Exploration, School of (SESE)

Research output: Contribution to journal › Article › peer-review

150 Scopus citations

Abstract

We explore canyon incision history of the western margin of the Andean (Altiplano-Puna) plateau in the central Andes as a proxy for surface uplift. (U-Th)/He apatite data show rapid cooling beginning at ca. 9 Ma and continuing to ca. 5.1 Ma in response to incision. A minimum of 1.0 km of incision took place during that interval. The youngest apatite date and a volcanic flow perched 125 m above the present valley floor dated at 2.261 ± 0.046 Ma (⁴⁰Ar/³⁹Ar) show that an additional ∼1.4 km of incision occurred between ca. 5.1 and 2.3 Ma. Thus, we infer that a total of at least 2.4 km, or 75% of the present canyon depth was incised after ca. 9 Ma. (U-Th)/He zircon data collected along the same transect imply that the western margin of the plateau was warped upward into its present monoclinal form, rather than uplift being accommodated on major surface-breaking faults.

Original language	English (US)
Pages (from-to)	523-526
Number of pages	4
Journal	Geology
Volume	35
Issue number	6
DOIs	https://doi.org/10.1130/G23532A.1
State	Published - Jun 2007

Keywords

Altiplano
Geochronology
Geomorphology
Helium
Peru
Tectonics

ASJC Scopus subject areas

Geology

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10.1130/G23532A.1

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title = "Uplift of the western margin of the Andean plateau revealed from canyon incision history, southern Peru",

abstract = "We explore canyon incision history of the western margin of the Andean (Altiplano-Puna) plateau in the central Andes as a proxy for surface uplift. (U-Th)/He apatite data show rapid cooling beginning at ca. 9 Ma and continuing to ca. 5.1 Ma in response to incision. A minimum of 1.0 km of incision took place during that interval. The youngest apatite date and a volcanic flow perched 125 m above the present valley floor dated at 2.261 ± 0.046 Ma (40Ar/39Ar) show that an additional ∼1.4 km of incision occurred between ca. 5.1 and 2.3 Ma. Thus, we infer that a total of at least 2.4 km, or 75% of the present canyon depth was incised after ca. 9 Ma. (U-Th)/He zircon data collected along the same transect imply that the western margin of the plateau was warped upward into its present monoclinal form, rather than uplift being accommodated on major surface-breaking faults.",

keywords = "Altiplano, Geochronology, Geomorphology, Helium, Peru, Tectonics",

author = "Schildgen, {Taylor F.} and Kip Hodges and Whipple, {Peter W.} and Reiners, {Peter W.} and Pringle, {Malcolm S.}",

year = "2007",

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doi = "10.1130/G23532A.1",

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T1 - Uplift of the western margin of the Andean plateau revealed from canyon incision history, southern Peru

AU - Schildgen, Taylor F.

AU - Hodges, Kip

AU - Whipple, Peter W.

AU - Reiners, Peter W.

AU - Pringle, Malcolm S.

PY - 2007/6

Y1 - 2007/6

N2 - We explore canyon incision history of the western margin of the Andean (Altiplano-Puna) plateau in the central Andes as a proxy for surface uplift. (U-Th)/He apatite data show rapid cooling beginning at ca. 9 Ma and continuing to ca. 5.1 Ma in response to incision. A minimum of 1.0 km of incision took place during that interval. The youngest apatite date and a volcanic flow perched 125 m above the present valley floor dated at 2.261 ± 0.046 Ma (40Ar/39Ar) show that an additional ∼1.4 km of incision occurred between ca. 5.1 and 2.3 Ma. Thus, we infer that a total of at least 2.4 km, or 75% of the present canyon depth was incised after ca. 9 Ma. (U-Th)/He zircon data collected along the same transect imply that the western margin of the plateau was warped upward into its present monoclinal form, rather than uplift being accommodated on major surface-breaking faults.

AB - We explore canyon incision history of the western margin of the Andean (Altiplano-Puna) plateau in the central Andes as a proxy for surface uplift. (U-Th)/He apatite data show rapid cooling beginning at ca. 9 Ma and continuing to ca. 5.1 Ma in response to incision. A minimum of 1.0 km of incision took place during that interval. The youngest apatite date and a volcanic flow perched 125 m above the present valley floor dated at 2.261 ± 0.046 Ma (40Ar/39Ar) show that an additional ∼1.4 km of incision occurred between ca. 5.1 and 2.3 Ma. Thus, we infer that a total of at least 2.4 km, or 75% of the present canyon depth was incised after ca. 9 Ma. (U-Th)/He zircon data collected along the same transect imply that the western margin of the plateau was warped upward into its present monoclinal form, rather than uplift being accommodated on major surface-breaking faults.

KW - Altiplano

KW - Geochronology

KW - Geomorphology

KW - Helium

KW - Peru

KW - Tectonics

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JO - Geology

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ER -

Uplift of the western margin of the Andean plateau revealed from canyon incision history, southern Peru

Abstract

Keywords

ASJC Scopus subject areas

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