Abstract. Reconstructing Oligocene-Miocene paleoelevation contributes to our understanding of the evolutionary history of the European Alps and sheds light on geodynamic and Earth’s surface processes involved in the development of Alpine topography. Despite being one of the most intensively explored mountain ranges worldwide, constraints on the elevation history of the European Alps, however, remain scarce. Here we present stable and clumped isotope geochemistry measurements to provide a new paleoelevation estimate for the mid-Miocene (~14.5 Ma) European Central Alps. We apply stable isotope δ-δ paleoaltimetry on near sea level pedogenic carbonate oxygen isotope (δ¹⁸O) records from the Northern Alpine Foreland Basin (Swiss Molasse Basin) and high-Alpine phyllosilicate hydrogen isotope (δD) records from the Simplon Fault Zone (Swiss Alps). We further explore Miocene paleoclimate and paleoenvironmental conditions in the Swiss Molasse Basin through carbonate stable (δ¹⁸O, δ¹³C) and clumped (Δ₄₇) isotope data from three foreland basin sections in different alluvial megafan settings (proximal, mid-fan, and distal). Combined pedogenic carbonate δ¹⁸O values and Δ₄₇ temperatures (30 ± 5 °C) yield a near sea level precipitation δ¹⁸O_w value of −5.8 ± 0.2 ‰ and in conjunction with the high-Alpine phyllosilicate δD record suggest that the region surrounding the SFZ attained surface elevations of > 4000 m no later than the mid-Miocene. Our near sea level δ¹⁸O_w estimate is supported by paleoclimate (iGCM Echam5-wiso) modeled δ¹⁸O values, which vary between −4.2 and −7.6 ‰ for the Northern Alpine Foreland Basin.

中文翻译：

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中阿尔卑斯山的中新世高海拔和高地势

摘要。重建渐新世-中新世古海拔有助于我们了解欧洲阿尔卑斯山的演化历史，并阐明高山地形发展所涉及的地球动力学和地球表面过程。尽管是世界上探索最深入的山脉之一，但欧洲阿尔卑斯山海拔历史的限制仍然很少。在这里，我们提出了稳定和成簇的同位素地球化学测量结果，以提供对中中新世（~14.5 Ma）欧洲中部阿尔卑斯山的新古海拔估计。我们对近海平面成土碳酸盐氧同位素（δ ¹⁸O) 来自北高山前陆盆地（瑞士莫拉塞盆地）的记录和来自辛普朗断裂带（瑞士阿尔卑斯山）的高山页硅酸盐氢同位素 (δD) 记录。我们通过碳酸盐稳定（δ ¹⁸ O，δ ¹³ C）和成簇（Δ ₄₇）同位素数据进一步探索了瑞士莫拉塞盆地中新世古气候和古环境条件，这些同位素数据来自不同冲积巨型扇环境（近端、中扇、中扇、中扇）的三个前陆盆地剖面。和远端）。结合成土碳酸盐 δ ¹⁸ O 值和 Δ ₄₇温度 (30 ± 5 °C) 产生近海平面降水 δ ¹⁸ O _w-5.8 ± 0.2 ‰ 的值并结合高山页硅酸盐 δD 记录表明，SFZ 周围的区域在不迟于中新世中期达到了 > 4000 m 的地表高度。我们对近海平面 δ ¹⁸ O _{w 的}估计得到了古气候 (iGCM Echam5-wiso) 模拟的 δ ¹⁸ O 值的支持，该值在北高山前陆盆地的 -4.2 到 -7.6 ‰ 之间变化。