Abstract The Central Andes between 18°S and 36°S latitude strike north-south for 2000 km along the Chilean subduction margin, cross several climate zones from hyperarid to humid and exhibit mean elevations in excess of 4000 m.a.s.l. Here, we investigate the relationships between tectonics, climate and exhumation by inverting low-temperature thermochronological data compiled from the literature (824 ages from 549 samples) and new data (238 ages from 146 samples) to quantify the exhumation rate history of the Central Andes since 80 Ma. Our inferred exhumation rates west of the drainage divide and between 18 and 32°S did not exceed 0.25 km/Ma. Such low exhumation rates are consistent with low shortening rates and arid conditions in this region. Local pulses of exhumation occurred only during the Eocene as response to active deformation and during the Miocene, probably as response to uplift of the western Andean slope. East of the drainage divide between 18 and 28°S, the observed exhumation pattern reflects the onset and eastward propagation of deformation. Here, exhumation occurred locally since the middle-to-late Eocene in the Eastern Cordillera and the Altiplano-Puna and subsequently affected larger parts of these regions and the north-western Sierra Pampeanas during the Oligocene. In the early Miocene (~20 Ma), the Interandean zone started exhuming and at 12-10 Ma exhumation propagated into the Subandean zone. Enhanced shortening rates and intensified precipitation along the eastern deformation front associated with the onset of the South American Monsoon led to increased exhumation rates in the eastern Interandean and the Subandean zones in the Plio-Pleistocene (0.6 km/Ma). Higher Pleistocene exhumation rates are also observed in the northern Sierra Pampeanas (1.5 km/Ma) that can be related to rock uplift along steep reverse faults coupled with high precipitation. South of 32°S on the western side, exhumation rates in the Principal Cordillera increased from ca. 0.25 km/Ma in the Miocene to rates locally exceeding 2 km/Ma in the Pleistocene. Whereas the tectonic regime in the southern Principal Cordillera remained unchanged since the late Miocene, these higher rates are likely associated with enhanced erosion resulting from intensified Pleistocene precipitation and glacial growth in this region, reinforced by isostatic rock uplift and active tectonics. Our study shows that the onset of exhumation correlates mainly with the initiation of horizontal shortening and crustal thickening, whereas the magnitude of exhumation is largely set by the amount of precipitation and glacial erosion and by the style of deformation, which is controlled by inherited structures and the amount of sediments in the foreland.

中文翻译：

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中部安第斯山脉（18-36°S）的构造、气候和挖掘之间的关系：来自低温热年代学的证据

摘要 位于 18°S 和 36°S 之间的中部安第斯山脉沿智利俯冲边缘南北走向 2000 公里，跨越从超干旱到潮湿的几个气候带，平均海拔超过 4000 masl。通过对文献（549 个样本中的 824 个年龄）和新数据（146 个样本中的 238 个年龄）汇编的低温热年代学数据进行反演，以量化自 80 Ma 以来中部安第斯山脉的剥落率历史，从而对构造、气候和剥蚀进行分析。我们推断的排水沟以西和 18 到 32°S 之间的折返率不超过 0.25 公里/马。如此低的挖掘率与该地区的低起酥率和干旱条件相一致。局部剥露脉冲仅在始新世期间发生，作为对活动变形的响应，而在中新世期间，可能作为对西安第斯斜坡抬升的响应。在 18°S 和 28°S 之间的排水分界线以东，观察到的折返模式反映了变形的开始和向东传播。在这里，自始新世东科迪勒拉山脉和高原-普纳山脉的中晚期始新世以来，局部发生了挖掘，随后在渐新世期间影响了这些地区的大部分地区和西北部的潘佩纳山脉。在早中新世（~20 Ma），Interandean 带开始开采，并在 12-10 Ma 开采传播到 Subandean 带。与南美季风爆发相关的东部变形前缘的缩短率增加和降水加剧，导致上新世的东部 Interandean 和 Subandean 带的挖掘率增加（0.6 km/Ma）。在潘佩纳山脉北部 (1.5 公里/Ma) 也观察到更高的更新世折返率，这可能与沿陡峭反向断层的岩石隆起以及大量降水有关。在西侧 32°S 以南，主科迪勒拉的挖掘率从大约 中新世 0.25 公里/马到更新世当地超过 2 公里/马。而自中新世晚期以来，南主科迪勒拉的构造体制保持不变，这些较高的速率可能与该地区更新世降水和冰川生长加剧导致侵蚀加剧有关，而等静压岩石隆起和活动构造又加强了侵蚀。我们的研究表明，折返的开始主要与水平缩短和地壳增厚的开始有关，而折返的幅度主要取决于降水和冰川侵蚀量以及变形方式，而变形方式受遗传结构和地壳的控制。前陆沉积物的数量。