Cenozoic sedimentary rocks of the intermontane Bagua Basin record the Andean orogenic history of northern Peru at ~4–7°S. The northern Peruvian Andes define the northern termination of the Central Andes and are comprised of a narrow, low‐elevation orogen relative to the rest of the Central Andes. New stratigraphic and sedimentologic field observations, subsidence analysis, and detrital zircon provenance analysis enable reconstruction of the regional tectonic history. Late Cretaceous to Paleocene detrital zircon U‐Pb age spectra from the Fundo El Triunfo and Rentema formations reveal active volcanism in the Western Cordillera as early as ~80 Ma and early exhumation of Mesozoic rocks in a nascent Marañon Fold‐Thrust Belt. Eocene fluvial deposits of the Cajaruro Formation record a progressive increase in shortening and volcanism in the Western Cordillera. The upper Eocene–middle Miocene fluvial succession of the Sambimera Formation records deposition in a proximal foredeep setting. Sambimera deposits contain syndepositional detrital zircon U‐Pb age populations that reveal a major Cenozoic magmatic source in the west. An erosive boundary separates the Sambimera from the overlying San Antonio Formation. The San Antonio Formation was deposited in an intermontane basin associated with uplift of the Eastern Cordillera at these latitudes. These results highlight a foreland progression of fold‐thrust deformation, with shortening concentrated in the Western Cordillera from latest Cretaceous to middle Miocene time. We suggest that the late Miocene transition to intermontane deposition in the Bagua Basin marks initial exhumation during shortening of the Eastern Cordillera in northern Peru.

中文翻译：

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秘鲁北部Campanian–新生代Bagua盆地的安第斯山脉生长与前陆盆地演化耦合

巴瓜山间盆地的新生代沉积岩记录了秘鲁北部约4-7°S的安第斯造山历史。秘鲁安第斯山脉北部定义了中部安第斯山脉的北端，相对于中部安第斯山脉的其余部分而言，它由一个狭窄的低海拔造山带组成。新的地层和沉积学实地观测，沉降分析以及碎屑锆石物源分析使该地区的构造历史得以重建。Fundo El Triunfo和Rentema地层的晚白垩世至古新世碎屑锆石U-Pb年龄谱揭示了早在约80 Ma时西部科尔迪勒拉就有活跃的火山作用，而新生的Marañon褶皱-冲断带中生代岩石则早出土。Cajaruro组的始新世河流相沉积物记录了西部山脉的缩短和火山活动的逐步增加。Sambimera组的上新世—中新世中上游河流相序记录了近前前倾环境中的沉积。Sambimera矿床包含同沉积碎屑锆石U-Pb年龄种群，揭示了西部主要的新生代岩浆来源。侵蚀性边界将Sambimera与上覆的圣安东尼奥组分开。圣安东尼奥组沉积在这些纬度与东部山脉山脉隆升相关的山间盆地中。这些结果突显了前陆褶皱冲断变形的进展，缩短的时间集中在西部山脉，从最近白垩纪到中新世中期。