Abstract. After more than a century of research, the chronology of the deformation of the external part of the Alpine belt is still controversial for the Miocene epoch. In particular, the poor dating of the foreland basin sedimentary succession hampers a comprehensive understanding of the kinematics of the deformation. Here we focus on the Miocene Molasse deposits of the northern subalpine massifs, southern Jura, Royans, Bas-Dauphiné, Crest and La Bresse sedimentary basins through a multidisciplinary approach to build a basin-wide tectono-stratigraphic framework. Based on sequence stratigraphy constrained by biostratigraphical, chemostratigraphical (Sr-isotopes) and magnetostratigraphical data between the late Aquitanian (~21 Ma) and the Tortonian (~8.2 Ma), the Miocene Molasse chronostratigraphy is revised with a precision of ~0.5 Ma. The Miocene Molasse sediments encompass four different palaeogeographical domains: (i) the oriental domain, outlined by depositional sequences S1a to S3 (~21 to ~15 Ma), (ii) the median domain characterized by sequences S2 to S5 (~17.8 to ~12 Ma), (iii) the occidental domain, in which sequences S2a to S8 (~17.8 to ~8.2 Ma) were deposited and, (iv) the Bressan domain, where sedimentation is restricted to sequences S6 to S8 (~12 to ~8.2 Ma). A structural and tectono-sedimentary study is conducted based on new field observations and the reappraisal of regional seismic profiles, thereby allowing the identification of five major faults zones (FZ). The oriental, median and occidental paleogeographical domains are clearly separated by FZ1, FZ2 and FZ3, suggesting strong interactions between tectonics and sedimentation during the Miocene. The evolution in time and space of the paleogeographical domains within a well-constrained structural framework reveals syntectonic deposits and a westward migration of the depocenters, and allows to establish the following chronology of thrust propagation at the western alpine front: (i) A compressive phase (P1) corresponding to thrusting above the Chartreuse Orientale Thrust (FZ1), which was likely initiated during the Oligocene. This tectonic phase generated reliefs that limited the Miocene transgression to the east; (ii) the ~W-WNW/E-ESE-directed compressive phase (P2) involving the Belledonne basal thrust, which activated the Salève thrust (SAL) fault and successively FZ2 to FZ5 from east to west. Phase P2 deeply shaped the Miocene palaeogeographical evolution and most probably corresponded to a prominent compressive phase at the scale of the Alps during the early to middle Miocene (between 18.05 +/- 0.25 Ma and ~12 Ma). In those ~6 Myr, the Miocene sea was forced to regress rapidly westwards in response to westward migration of the active thrusts and exhumation of piggy-back basins atop the fault zones; (iii) the last phase (P3) of Tortonian age (~10 Ma), which likely implied a significant uplift (350 m minimum) of the Bas-Dauphiné basin, whereas horizontal motions prevailed within the Jura Mountains.

中文翻译：

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中新世磨拉石（阿尔卑斯山西部）更新的构造-沉积框架的推力传播年代学

摘要。经过一个多世纪的研究，中新世高山带外部变形的年代学仍存在争议。特别是前陆盆地沉积层序的不良年代测定阻碍了对变形运动学的全面了解。在这里，我们通过多学科方法关注北部亚高山地块、南部侏罗、Royans、Bas-Dauphiné、Crest 和 La Bresse 沉积盆地的中新世 Molasse 矿床，以构建盆地范围的构造地层框架。基于受生物地层学、化学地层学（Sr 同位素）和晚阿基坦阶（~21 Ma）和托尔顿阶（~8.2 Ma）之间的磁地层数据约束的层序地层学，中新世 Molasse 年代地层学以~0.5 Ma 的精度进行了修正。中新世 Molasse 沉积物包括四个不同的古地理区域：(i) 东方区域，由沉积序列 S1a 到 S3（~21 到 ~15 Ma）勾勒，（ii）以序列 S2 到 S5（~17.8 到 ~ 12 Ma），（iii）西方域，其中沉积了序列 S2a 至 S8（~17.8 至~8.2 Ma），以及（iv）Bressan 域，其中沉积仅限于序列 S6 至 S8（~12 至~ 8.2 马）。基于新的现场观测和区域地震剖面的重新评估，进行了结构和构造沉积研究，从而确定了五个主要断层带 (FZ)。FZ1、FZ2 和 FZ3 清楚地将东方、中层和西方古地理域分隔开来，表明中新世构造和沉积之间存在强烈的相互作用。受良好约束的构造框架内古地理域的时间和空间演变揭示了同构造沉积和沉积中心向西迁移，并允许建立以下高山前缘推力传播的年表：(i) 压缩相(P1) 对应于 Chartreuse Orientale Thrust (FZ1) 上方的推力，这可能是在渐新世期间开始的。这一构造阶段产生的地势限制了中新世向东的海侵；(ii) ~W-WNW/E-ESE 导向的压缩阶段 (P2)，涉及 Belledonne 基底逆冲断层，激活了 Salève 逆冲断层 (SAL)，从东到西依次为 FZ2 至 FZ5。P2 相深刻地塑造了中新世古地理演化，最有可能对应于中新世早期至中期（18.05 +/- 0.25 Ma 和~12 Ma）期间阿尔卑斯山规模的显着压缩相。在大约 6 Myr 中，中新世海被迫迅速向西倒退，以响应活动逆冲断层向西迁移和断层带顶部背负式盆地的剥脱；(iii) Tortonian 时代（~10 Ma）的最后阶段（P3），这可能意味着 Bas-Dauphiné 盆地显着隆起（最小 350 m），而侏罗山脉内水平运动盛行。中新世海被迫迅速西退，以响应活动逆冲向西迁移和断层带顶部背负盆地的剥脱；(iii) Tortonian 时代（~10 Ma）的最后阶段（P3），这可能意味着 Bas-Dauphiné 盆地显着隆起（最小 350 m），而侏罗山脉内水平运动盛行。中新世海被迫迅速西退，以响应活动逆冲向西迁移和断层带顶部背负盆地的剥脱；(iii) Tortonian 时代（~10 Ma）的最后阶段（P3），这可能意味着 Bas-Dauphiné 盆地显着隆起（最小 350 m），而侏罗山脉内水平运动盛行。