Punctuated shortening and subsidence in the Altiplano Plateau of southern Peru: Implications for early Andean mountain building

Brian K. Horton, Nicholas D. Perez, Justin D. Fitch, Joel E Saylor

Research output: Contribution to journalArticle

17 Citations (Scopus)

Abstract

Sedimentologic, provenance, geochronologic, and magnetostratigraphic results from clastic nonmarine deposits in the northern Altiplano Plateau of southern Peru (14-15°S) demonstrate late Eocene-Oligocene (37-26 Ma) accumulation of the >4-km-thick San Jerónimo (Puno) Group within a retroarc foreland basin related to early Andean shortening and crustal thickening. Punctuated Oligocene (29-26 Ma) displacement along deep-seated contractional structures, as revealed by growth stratal relationships, abruptly partitioned this regional flexural basin and established the structural boundaries of the smaller intermontane Ayaviri Basin, which continued to evolve in a hinterland setting during late Oligocene-Miocene shortening. This brief episode of shortening along the Altiplano-Eastern Cordillera boundary is correlated with exceptionally rapid sediment accumulation (>1100-1800 m/m.y.), tightly constrained to 30-28 Ma on the basis of U-Pb geochronology and magnetic polarity stratigraphy. Provenance data from detrital zircon U-Pb age populations and sandstone compositions indicate derivation from a complex belt of Paleogene shortening and probable basin inversion in the Western Cordillera that was subsequently overprinted by Andean arc magmatism. This early Andean zone is interpreted as the along-strike continuation of the better-exposed Marañon fold-thrust belt to the north (5-13°S) and a proposed belt of shortening to the south along the Chilean Precordillera and Western Cordillera of Bolivia and northern Argentina (17-25°S). Subsequent focusing of late Oligocene shortening along the Eastern Cordillera-Altiplano boundary may have been linked to shallowing of the subducting slab and potential reactivation of crustal anisotropies.

Original languageEnglish (US)
Pages (from-to)117-137
Number of pages21
JournalLithosphere
Volume7
Issue number2
DOIs
StatePublished - 2015
Externally publishedYes

Fingerprint

cordillera
Oligocene
subsidence
plateau
mountain
provenance
intermontane basin
crustal thickening
foreland basin
reactivation
basin
geochronology
Paleogene
magmatism
slab
Eocene
zircon
anisotropy
stratigraphy
thrust

ASJC Scopus subject areas

  • Geology

Cite this

Punctuated shortening and subsidence in the Altiplano Plateau of southern Peru : Implications for early Andean mountain building. / Horton, Brian K.; Perez, Nicholas D.; Fitch, Justin D.; Saylor, Joel E.

In: Lithosphere, Vol. 7, No. 2, 2015, p. 117-137.

Research output: Contribution to journalArticle

@article{598077475610437a867b95f7f9b6fd94,
title = "Punctuated shortening and subsidence in the Altiplano Plateau of southern Peru: Implications for early Andean mountain building",
abstract = "Sedimentologic, provenance, geochronologic, and magnetostratigraphic results from clastic nonmarine deposits in the northern Altiplano Plateau of southern Peru (14-15°S) demonstrate late Eocene-Oligocene (37-26 Ma) accumulation of the >4-km-thick San Jer{\'o}nimo (Puno) Group within a retroarc foreland basin related to early Andean shortening and crustal thickening. Punctuated Oligocene (29-26 Ma) displacement along deep-seated contractional structures, as revealed by growth stratal relationships, abruptly partitioned this regional flexural basin and established the structural boundaries of the smaller intermontane Ayaviri Basin, which continued to evolve in a hinterland setting during late Oligocene-Miocene shortening. This brief episode of shortening along the Altiplano-Eastern Cordillera boundary is correlated with exceptionally rapid sediment accumulation (>1100-1800 m/m.y.), tightly constrained to 30-28 Ma on the basis of U-Pb geochronology and magnetic polarity stratigraphy. Provenance data from detrital zircon U-Pb age populations and sandstone compositions indicate derivation from a complex belt of Paleogene shortening and probable basin inversion in the Western Cordillera that was subsequently overprinted by Andean arc magmatism. This early Andean zone is interpreted as the along-strike continuation of the better-exposed Mara{\~n}on fold-thrust belt to the north (5-13°S) and a proposed belt of shortening to the south along the Chilean Precordillera and Western Cordillera of Bolivia and northern Argentina (17-25°S). Subsequent focusing of late Oligocene shortening along the Eastern Cordillera-Altiplano boundary may have been linked to shallowing of the subducting slab and potential reactivation of crustal anisotropies.",
author = "Horton, {Brian K.} and Perez, {Nicholas D.} and Fitch, {Justin D.} and Saylor, {Joel E}",
year = "2015",
doi = "10.1130/L397.1",
language = "English (US)",
volume = "7",
pages = "117--137",
journal = "Lithosphere",
issn = "1941-8264",
publisher = "Geological Society of America",
number = "2",

}

TY - JOUR

T1 - Punctuated shortening and subsidence in the Altiplano Plateau of southern Peru

T2 - Implications for early Andean mountain building

AU - Horton, Brian K.

AU - Perez, Nicholas D.

AU - Fitch, Justin D.

AU - Saylor, Joel E

PY - 2015

Y1 - 2015

N2 - Sedimentologic, provenance, geochronologic, and magnetostratigraphic results from clastic nonmarine deposits in the northern Altiplano Plateau of southern Peru (14-15°S) demonstrate late Eocene-Oligocene (37-26 Ma) accumulation of the >4-km-thick San Jerónimo (Puno) Group within a retroarc foreland basin related to early Andean shortening and crustal thickening. Punctuated Oligocene (29-26 Ma) displacement along deep-seated contractional structures, as revealed by growth stratal relationships, abruptly partitioned this regional flexural basin and established the structural boundaries of the smaller intermontane Ayaviri Basin, which continued to evolve in a hinterland setting during late Oligocene-Miocene shortening. This brief episode of shortening along the Altiplano-Eastern Cordillera boundary is correlated with exceptionally rapid sediment accumulation (>1100-1800 m/m.y.), tightly constrained to 30-28 Ma on the basis of U-Pb geochronology and magnetic polarity stratigraphy. Provenance data from detrital zircon U-Pb age populations and sandstone compositions indicate derivation from a complex belt of Paleogene shortening and probable basin inversion in the Western Cordillera that was subsequently overprinted by Andean arc magmatism. This early Andean zone is interpreted as the along-strike continuation of the better-exposed Marañon fold-thrust belt to the north (5-13°S) and a proposed belt of shortening to the south along the Chilean Precordillera and Western Cordillera of Bolivia and northern Argentina (17-25°S). Subsequent focusing of late Oligocene shortening along the Eastern Cordillera-Altiplano boundary may have been linked to shallowing of the subducting slab and potential reactivation of crustal anisotropies.

AB - Sedimentologic, provenance, geochronologic, and magnetostratigraphic results from clastic nonmarine deposits in the northern Altiplano Plateau of southern Peru (14-15°S) demonstrate late Eocene-Oligocene (37-26 Ma) accumulation of the >4-km-thick San Jerónimo (Puno) Group within a retroarc foreland basin related to early Andean shortening and crustal thickening. Punctuated Oligocene (29-26 Ma) displacement along deep-seated contractional structures, as revealed by growth stratal relationships, abruptly partitioned this regional flexural basin and established the structural boundaries of the smaller intermontane Ayaviri Basin, which continued to evolve in a hinterland setting during late Oligocene-Miocene shortening. This brief episode of shortening along the Altiplano-Eastern Cordillera boundary is correlated with exceptionally rapid sediment accumulation (>1100-1800 m/m.y.), tightly constrained to 30-28 Ma on the basis of U-Pb geochronology and magnetic polarity stratigraphy. Provenance data from detrital zircon U-Pb age populations and sandstone compositions indicate derivation from a complex belt of Paleogene shortening and probable basin inversion in the Western Cordillera that was subsequently overprinted by Andean arc magmatism. This early Andean zone is interpreted as the along-strike continuation of the better-exposed Marañon fold-thrust belt to the north (5-13°S) and a proposed belt of shortening to the south along the Chilean Precordillera and Western Cordillera of Bolivia and northern Argentina (17-25°S). Subsequent focusing of late Oligocene shortening along the Eastern Cordillera-Altiplano boundary may have been linked to shallowing of the subducting slab and potential reactivation of crustal anisotropies.

UR - http://www.scopus.com/inward/record.url?scp=84928262460&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84928262460&partnerID=8YFLogxK

U2 - 10.1130/L397.1

DO - 10.1130/L397.1

M3 - Article

AN - SCOPUS:84928262460

VL - 7

SP - 117

EP - 137

JO - Lithosphere

JF - Lithosphere

SN - 1941-8264

IS - 2

ER -