ENVIRONMENTAL SIGNAL PROPAGATION AND PRESERVATION ACROSS THE SOUTH PYRENEAN BASINS: LINKING PROVENANCE WITH CLIMATE MODULATED TECTONIC EXHUMATION

Environmental signals of tectonic and climatic perturbations preserved in foreland basin sediments reveal the spatio-temporal evolution of sediment delivery systems from orogenic source regions to depositional sinks. This study presents a comprehensive detrital zircon (DZ) U-Pb provenance dataset of 176 samples (legacy and new) from late Cretaceous – Oligocene deposits of the South Pyrenean foreland basins to explore the coupled foreland basin and orogenic evolution. We integrate DZ U-Pb geochronology data with bedrock and detrital low-temperature thermochronology data to reveal the sediment source region thermal history, and one-dimensional thermal modeling (Tc1D) to quantify the relationship between tectonic uplift, climate modulated erosion, and sediment generation. Non-negative matrix factorization (NMF) is applied to reconstruct the DZ signatures of potential sediment sources and quantify their relative contributions to the DZ signatures. NMF disentangles multimodal DZ signatures of recycled sedimentary and metasedimentary units and identifies unique signals of sediment sources. These provenance proxies and reconstructed source proportions are used to test proposed stratigraphic correlations between the alluvial/fluvial deposits in the Tremp-Gras, Ripoll, and Ager basins to deep marine deposits in the Ainsa and Jaca basins throughout the Paleogene.

Preliminary results indicate the basin-scale long-term (10s Myr) provenance evolution changes from sediment sources south of the Pyrenean domain in pre-orogenic deposits to sediment sources of mixed first cycle and recycled zircons in the eastern Pyrenean hinterland which evolve to sediment sources in the central and western Pyrenean hinterland mixed with locally derived sediments from exhumed foreland deposits. Signals of sediment transfer and depositional processes that operate on intermediate timescales (10s Kyr – 1 Myr), such as eustatically driven sea-level variability, pulsed activation of thin-skinned thrust structures, and climatically controlled fluctuations in precipitation and temperature are superposed onto the signals of longer-term basin scale drainage evolution. We detect these signals by pairing the detrital provenance record with published stable isotope climate proxy constraints and evidence of Cenozoic hyperthermal events in the stratigraphic architecture.