气候变化领域集成服务门户(CCPortal): Diagnosing an ancient shallow-angle subduction event from Cenozoic depositional and deformational records in the central Andes of southern Peru

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DOI	10.1016/j.epsl.2020.116263
	Diagnosing an ancient shallow-angle subduction event from Cenozoic depositional and deformational records in the central Andes of southern Peru
	Perez N.D.; Levine K.G.
发表日期	2020
ISSN	0012821X
卷号	541
英文摘要	The spectrum of responses exhibited by upper plates to changes in the subduction zone geometry remains poorly constrained. In the Paleogene, the central Andes in southern Peru potentially experienced an episode of flat or shallow-angle subduction. Presented here are new geochronologic, thermochronologic, basin subsidence backstripping analysis, and 2D flexural modeling results. These are synthesized with existing records on the temporal variation of the volcanic arc position, basin fill chronostratigraphy, deformation style and location, and geophysical constraints on lithospheric architecture to investigate how this segment of the Andes developed during a proposed ancient modification to the subduction zone dip. Basin chronostratigraphy confirms persistent contribution from volcanic arc products during the Eocene–Miocene, arguing against complete cessation of arc magmatism. Sediment accumulation was pulsed and generally more rapid during the late Eocene–Oligocene event. The subsidence curve is generally concave-up, atypical for a foreland basin situated within the compressional central Andes. The tectonic subsidence magnitude observed from backstripping analysis is at least 1 km less than the magnitude of subsidence predicted by 2D flexural model results. This suggests a component of basin uplift, potentially as a dynamic response to subduction shallowing, may have opposed flexural subsidence that was driven by crustal thickening and topographic loading. New geo- and thermochronologic results constrain the timing of Late Triassic pluton emplacement, and initial unroofing that predates the proposed timing of flat or shallow-angle subduction. This new timing suggests initial deformation, with mixed thin- and thick-skinned deformation style, in the Eastern Cordillera may be linked to reactivation of inherited structures rather than inboard deformation advance as a response to subduction flattening. The lack of basement-cored uplifts, preservation of mantle lithosphere beneath this segment of the central Andes, and volcanic arc patterns argue against the occurrence of a flat slab event. Instead, these results point to a shallow-angle subduction event and highlight the diverse behaviors of Cordilleran margins affected by variable subduction zone geometry and upper plates with inherited crustal heterogeneities. © 2020 Elsevier B.V.
关键词	central Andes flat-slab fold-thrust belts foreland basins tectonics thermochronology
英文关键词	Deformation; Plates (structural components); Volcanoes; Chronostratigraphy; Crustal thickenings; Eastern Cordillera; Mantle lithosphere; Pluton emplacement; Sediment accumulation; Temporal variation; Thick-skinned deformations; Subsidence; Cenozoic; chronostratigraphy; paleoenvironment; structural geology; subduction; subduction zone; tectonic evolution; tectonic setting; volcanic arc; Andes; Peru
语种	英语
来源期刊	Earth and Planetary Science Letters
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/202830
作者单位	Department of Geology and Geophysics, College of Geosciences, Texas A&M University, College Station, TX 77843, United States
推荐引用方式 GB/T 7714	Perez N.D.,Levine K.G.. Diagnosing an ancient shallow-angle subduction event from Cenozoic depositional and deformational records in the central Andes of southern Peru[J],2020,541.
APA	Perez N.D.,&Levine K.G..(2020).Diagnosing an ancient shallow-angle subduction event from Cenozoic depositional and deformational records in the central Andes of southern Peru.Earth and Planetary Science Letters,541.
MLA	Perez N.D.,et al."Diagnosing an ancient shallow-angle subduction event from Cenozoic depositional and deformational records in the central Andes of southern Peru".Earth and Planetary Science Letters 541(2020).