Projectdetails

Alluvial fan architecture typically reveals coarsening upward sequences on various scales that are commonly related to pulsating tectonics and/or autocyclic processes while climate is generally being neglected. The proposed research is meant to fill up this gap in our understanding of alluvial fan sedimentation by exploring causal links with astronomical climate forcing in unprecedented detail. We propose to study the sedimentary signatures and architecture of small-scale, coarse-clastic fan systems in the Calatayud-Teruel Basin, Spain, which developed along an active basin margin in a semi-arid climate setting during the late Miocene.

Astronomical climate forcing was recently proven for distal settings in the centre of the same basin, where the astronomical signals are better expressed. The challenge is to demonstrate the astronomical signal in alluvial fan successions from coeval proximal settings in the C-T Basin, to reconstruct processes and mechanisms of astronomical climate forcing and control on alluvial fan sedimentation, and to establish similarities and differences with the effects of tectonic and autocyclic forcing.

Generally, poor age constraints prevent testing of possible astronomical forcing of alluvial fan buildup, but in this case the alluvial fan sequences can be correlated with sedimentary cycles in adjacent, more distal, coeval successions for which timing and phase relations with the orbital parameters are known, and where even the Astronomical Polarity Time Scale (APTS) was recently extended from 10 Ma BP back to 13 Ma BP.

The results of this study will be compared with the outcome of climate-modelling experiments for different orbital extremes in late Miocene times and offer new avenues for the validation and where possible refinement of numerical stratigraphic models for alluvial fan deposition.