Miocene high elevation in the Central Alps
<p>Reconstructing Oligocene–Miocene paleoelevation contributes to our understanding of the evolutionary history of the European Alps and sheds light on geodynamic and Earth surface processes involved in the development of Alpine topography. Despite being one of the most intensively explored mo...
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| Autores principales: | , , , , , , , , , |
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| Formato: | article |
| Lenguaje: | EN |
| Publicado: |
Copernicus Publications
2021
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| Materias: | |
| Acceso en línea: | https://doaj.org/article/e0f5cc0bb9c8416f8c533fd0868aad4c |
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| Sumario: | <p>Reconstructing Oligocene–Miocene paleoelevation
contributes to our understanding of the evolutionary history of the European
Alps and sheds light on geodynamic and Earth 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 remain scarce. Here we present stable and
clumped isotope measurements to provide a new paleoelevation estimate for
the mid-Miocene (<span class="inline-formula">∼14.5</span> Ma) European Central Alps. We apply
stable isotope <span class="inline-formula"><i>δ</i></span>–<span class="inline-formula"><i>δ</i></span> paleoaltimetry to near-sea-level
pedogenic carbonate oxygen isotope (<span class="inline-formula"><i>δ</i></span><span class="inline-formula"><sup>18</sup>O</span>) records from the
Northern Alpine Foreland Basin (Swiss Molasse Basin) and high-Alpine
phyllosilicate hydrogen isotope (<span class="inline-formula"><i>δ</i></span>D) records from the Simplon Fault
Zone (Swiss Alps). We further explore Miocene paleoclimate and
paleoenvironmental conditions in the Swiss Molasse Basin through carbonate
stable (<span class="inline-formula"><i>δ</i></span><span class="inline-formula"><sup>18</sup>O</span>, <span class="inline-formula"><i>δ</i></span><span class="inline-formula"><sup>13</sup>C</span>) and clumped (<span class="inline-formula">Δ<sub>47</sub></span>)
isotope data from three foreland basin sections in different alluvial
megafan settings (proximal, mid-fan, and distal). Combined pedogenic
carbonate <span class="inline-formula"><i>δ</i></span><span class="inline-formula"><sup>18</sup>O</span> values and <span class="inline-formula">Δ<sub>47</sub></span> temperatures
(<span class="inline-formula">30±5</span> <span class="inline-formula"><sup>∘</sup>C</span>) yield a near-sea-level precipitation
<span class="inline-formula"><i>δ</i></span><span class="inline-formula"><sup>18</sup>O</span><span class="inline-formula"><sub>w</sub></span> value of <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M20" display="inline" overflow="scroll" dspmath="mathml"><mrow><mo>-</mo><mn mathvariant="normal">5.8</mn><mo>±</mo><mn mathvariant="normal">1.2</mn></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="52pt" height="10pt" class="svg-formula" dspmath="mathimg" md5hash="13b406664936feaf5e75451d90f4184e"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="se-12-2615-2021-ie00001.svg" width="52pt" height="10pt" src="se-12-2615-2021-ie00001.png"/></svg:svg></span></span> ‰ and, in
conjunction with the high-Alpine phyllosilicate <span class="inline-formula"><i>δ</i></span>D value of <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M22" display="inline" overflow="scroll" dspmath="mathml"><mrow><mo>-</mo><mn mathvariant="normal">14.6</mn><mo>±</mo><mn mathvariant="normal">0.3</mn></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="58pt" height="10pt" class="svg-formula" dspmath="mathimg" md5hash="70cef396af22bebea66738e43f6b1b90"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="se-12-2615-2021-ie00002.svg" width="58pt" height="10pt" src="se-12-2615-2021-ie00002.png"/></svg:svg></span></span> ‰, suggest that the region surrounding the
Simplon Fault Zone attained surface elevations of <span class="inline-formula">>4000</span> m no
later than the mid-Miocene. Our near-sea-level <span class="inline-formula"><i>δ</i></span><span class="inline-formula"><sup>18</sup>O</span><span class="inline-formula"><sub>w</sub></span>
estimate is supported by paleoclimate (iGCM ECHAM5-wiso) modeled <span class="inline-formula"><i>δ</i></span><span class="inline-formula"><sup>18</sup>O</span> values, which vary between <span class="inline-formula">−4.2</span> ‰ and <span class="inline-formula">−7.6</span> ‰ for
the Northern Alpine Foreland Basin.</p> |
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