Understanding the effects of flat slab subduction on mountain building, arc magmatism, and basin evolution is fundamental to convergent‐margin tectonics, with implications for potential feedbacks among geodynamic, magmatic, and surface processes. New stratigraphic and geochronological constraints on Cenozoic sedimentation and magmatism in the southern Central Andes of Argentina (31°S) reveal shifts in volcanism, foreland/hinterland basin development, sediment accumulation, and provenance as the retroarc region was structurally partitioned during slab flattening. Detrital zircon U‐Pb age distributions from the western (Calingasta basin), central (Talacasto and Albarracín basins), and eastern (Bermejo foreland basin) segments of the retroarc basin system preserve syndepositional volcanism and orogenic unroofing of multiple tectonic provinces. Initial shortening‐related exhumation of the Principal Cordillera at 24–17 Ma was recorded by the accumulation of distal eolian deposits bearing Oligocene–Eocene zircons from the Andean magmatic arc. The Calingasta basin chronicled volcanism and basement shortening in the Frontal Cordillera at ~17–11 Ma, as marked by an upward coarsening succession of fluvial to alluvial fan deposits with a sustained zircon U‐Pb age component that matches pervasive Permian‐Triassic bedrock in the hinterland. An ~450 km eastward inboard sweep of volcanism at 11 Ma coincided with the inception of flat slab subduction, and subsequent thin‐skinned shortening in the Precordillera fold‐thrust belt that exhumed wedge‐top deposits and induced cratonward (eastward) advance of flexural subsidence into the Bermejo foreland basin. This foreland basin was structurally partitioned as basement uplifts of the Sierras Pampeanas transformed a fluvial megafan sediment routing network into smaller isolated alluvial fan systems fed by adjacent basement blocks.

中文翻译：

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阿根廷西部对新板块后陆前陆盆地演化，沉积物产源和岩浆作用的响应

了解平面平板俯冲对山体建筑，弧岩岩浆作用和盆地演化的影响，对收敛边缘构造是至关重要的，它对地球动力学，岩浆作用和地表过程之间的潜在反馈具有影响。阿根廷中部安第斯山脉南部（31°S）对新生代沉积和岩浆作用的新的地层和地质年​​代学限制揭示了火山活动，前陆/腹地盆地发育，沉积物积累和物源的变化，因为在平板展平过程中后弧区域在结构上被划分。弧后盆地系统西部（Calingasta盆地），中部（Talacasto和Albarracín盆地）和东部（Bermejo前陆盆地）碎屑锆石U-Pb年龄分布保留了多个构造省份的同生火山作用和造山带顶。在安第斯岩浆弧中，渐新世-始新世锆石的末端风成岩堆积，记录了主要堇青石在24-17 Ma时发生的与缩短有关的发掘。卡林加斯塔盆地使锋芒山脉中的火山作用和基底缩短在约17-11 Ma处发生，其特征是河流相至冲积扇状沉积物的向上粗化序列，锆石具有U-Pb持续年龄成分，与该地区普遍的二叠纪-三叠纪基岩相匹配。腹地。在11 Ma上向东向东向450公里的火山扫掠与平板俯冲的发生相吻合，随后Precordillera褶皱冲断带薄层缩短，挖掘出楔顶沉积物，并引起挠曲沉降向东（向东）前进进入贝尔梅霍前陆盆地。