U–Pb dating of middle Eocene–Pliocene multiple tectonic pulses in the Alpine foreland
<p>Foreland fold-and-thrust belts (FTBs) record long-lived tectono-sedimentary activity, from passive margin sedimentation, flexuring, and further evolution into wedge accretion ahead of an advancing orogen. Therefore, dating fault activity is fundamental for plate movement reconstruction, res...
Guardado en:
| Autores principales: | , , , , , |
|---|---|
| Formato: | article |
| Lenguaje: | EN |
| Publicado: |
Copernicus Publications
2021
|
| Materias: | |
| Acceso en línea: | https://doaj.org/article/c6a5ea595903400a9389d0f0545c4916 |
| Etiquetas: |
Agregar Etiqueta
Sin Etiquetas, Sea el primero en etiquetar este registro!
|
| Sumario: | <p>Foreland fold-and-thrust belts (FTBs) record long-lived
tectono-sedimentary activity, from passive margin sedimentation, flexuring,
and further evolution into wedge accretion ahead of an advancing orogen.
Therefore, dating fault activity is fundamental for plate movement
reconstruction, resource exploration, and earthquake hazard assessment. Here,
we report U–Pb ages of syn-tectonic calcite mineralizations from four thrusts
and three tear faults sampled at the regional scale across the Jura
fold-and-thrust belt in the northwestern Alpine foreland (eastern France).
Three regional tectonic phases are recognized in the middle Eocene–Pliocene
interval: (1) pre-orogenic faulting at <span class="inline-formula">48.4±1.5</span> and <span class="inline-formula">44.7±2.6</span> Ma associated with the far-field effect of the Alpine or Pyrenean compression,
(2) syn-orogenic thrusting at <span class="inline-formula">11.4±1.1</span>, <span class="inline-formula">10.6±0.5</span>, <span class="inline-formula">9.7±1.4</span>, <span class="inline-formula">9.6±0.3</span>, and <span class="inline-formula">7.5±1.1</span> Ma associated with the
formation of the Jura fold-and-thrust belt with possible in-sequence thrust
propagation, and (3) syn-orogenic tear faulting at <span class="inline-formula">10.5±0.4</span>, <span class="inline-formula">9.1±6.5</span>, <span class="inline-formula">5.7±4.7</span>, and at <span class="inline-formula">4.8±1.7</span> Ma including the
reactivation of a pre-orogenic fault at <span class="inline-formula">3.9±2.9</span> Ma. Previously
unknown faulting events at <span class="inline-formula">48.4±1.5</span> and <span class="inline-formula">44.7±2.6</span> Ma predate the reported late Eocene age for tectonic activity
onset in the Alpine foreland by <span class="inline-formula">∼10</span> Myr. In addition, we date the previously inferred
reactivation of pre-orogenic strike-slip faults as tear faults during Jura
imbrication. The U–Pb ages document a minimal time frame for the evolution
of the Jura FTB wedge by possible in-sequence thrust imbrication above the
low-friction basal decollement consisting of evaporites.</p> |
|---|