The Mesozoic-Cenozoic sedimentary record of Andean mountain building

Accurate reconstructions of the Andes are fundamental to understanding the geodynamics of subduction-related mountain building along convergent plate boundaries and the climatic and biological evolution of South America. Andean sedimentary basins evolved in diverse structural settings, with retroarc crustal shortening, flexure, and rapid accumulation in long-lived foreland and hinterland basins, along with selected episodes of focused extension. Although the ultimate drivers of orogenesis remain unclear, construction of the Andes can be attributed to fluctuating contractional, neutral, and extensional tectonic regimes during differing degrees of mechanical coupling along the convergent plate boundary. Temporal and spatial shifts among these three contrasting tectonic regimes can be related to variable degrees of coupling during first-order plate-scale changes in convergence and second-order regional cycles of slab shallowing and steepening.

Speaker: Brian Horton, Univ. of Texas at Austin