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Andean forearc dynamics, as recorded by detrital zircon from the Eocene Talara Basin, northwest Peru

Angela M. Hessler and Andrea Fildani
Andean forearc dynamics, as recorded by detrital zircon from the Eocene Talara Basin, northwest Peru
Journal of Sedimentary Research (June 2015) 85 (6): 646-659

Abstract

Eocene strata of the Talara forearc basin of northwest Peru contain detrital-zircon (DZ) populations that, when integrated with other provenance indicators, record paleogeographic shifts in the Andean forearc that can be linked to larger-scale tectonic drivers such as subduction erosion, plate convergence rate, and regional accretion events. Because forearc basins along the western margin of South America are particularly difficult to preserve, the new DZ results provide rare insight into the trench-arc dynamics associated with the Andean orogenic cycle. The Talara basin tapped into both the Andean volcanic arc and older basement, and the DZ populations subsequently reflect long-lived plate interactions and progressive crustal growth along the northwestern edge of Amazonia, Gondwana, and South America. Dominant U-Pb zircon age populations include: 36-110 Ma (Andes convergence); 215-285 Ma (western Gondwana extension); 460-625 Ma (Rodinia extension and western Gondwana convergence); 950-1250 Ma (Grenville orogeny); and > 1250 Ma (Amazonia assembly). The data corroborate previous geochronology on pre-Andean basement and support the existence of a Famatinian arc ( approximately 480 Ma) and Carboniferous-Triassic magmatism along northwestern Gondwana. Pre-Andean and Amazonian DZ likely was recycled from Paleozoic metasedimentary rocks of the Andean Cordillera and Amotape terrane, although the data do not preclude delivery of Amazonian detritus directly into the forearc via a large-scale, westward drainage. The Andean DZ population constrains the timing of arc activity and quiescence, with two peaks at approximately 75 Ma and approximately 50 Ma, and a gap at approximately 70 Ma, linked to accretion of the Caribbean Oceanic Plateau against northwest South America. Arc volcanism was concurrent with Eocene forearc deposition, and syndepositional DZ is used to revise maximum depositional age for the upper Eocene Helico Member and Verdun Formation. Progressive subsidence and arc shut-down in the late Eocene coincide with arc collision to the north, uplift of the Amotape block, subduction erosion, and slab shallowing.


ISSN: 1527-1404
EISSN: 1938-3681
Serial Title: Journal of Sedimentary Research
Serial Volume: 85
Serial Issue: 6
Title: Andean forearc dynamics, as recorded by detrital zircon from the Eocene Talara Basin, northwest Peru
Affiliation: Deep Time Institute, Austin, TX, United States
Pages: 646-659
Published: 20150611
Text Language: English
Publisher: Society for Sedimentary Geology, Tulsa, OK, United States
References: 76
Accession Number: 2015-070012
Categories: Structural geologyGeochronology
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. geol. sketch maps
S04°25'00" - S04°25'00", W81°04'60" - W81°04'60"
Secondary Affiliation: Statoil Research, Development and Innovation Center, USA, United States
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Reference includes data from GeoScienceWorld, Alexandria, VA, United States. Reference includes data supplied by SEPM (Society for Sedimentary Geology), Tulsa, OK, United States
Update Code: 201530
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