Quaternary uplift rates along the Chilean Coast (19°S-31°S)

Final Report Abstract

The large scale uplift history along the coast of northern Chile shows a seesaw-like uplift history with the “pivot point” at Caldera. Uplift constrains south of Caldera show higher uplift rates pre 200 ka and lower uplift rates post 200 ka. North of Caldera we constrained the opposite uplift pattern with lower uplift rates pre 200 ka and higher rates post 200 ka. Unlike other recently published studies for this region we find uplift rates are neither constant in time nor space. The most viable mechanisms responsible for the broad-scale, long wavelength (~1000 km) variations in uplift along the coast are deep-seated processes, like changes at the plate interface. One possible mechanism that influenced the uplift of the upper continental crust is friction within the plate interface. The present day situation is that slightly more sediment is within the plate interface south of Caldera, compared to the sediment free trench north of Caldera. If the sediment is the driving mechanism that caused a reduction in plate friction and subsequent deceleration in uplift, changes in uplift could be related to changes in climate. In a focus study of the Mejillones Peninsula we identified 3 distinct periods of accelerated uplift and subsidence in response to long-term EW extension. A proximal anomaly in the pattern of plate coupling suggests that local uplift-rates and plate coupling are intricately linked.

Publications

• (2013): New terrace ages better constrain the uplift history for the Mejillones Peninsula, northern Chile. EGU General Assembly 2013, Vienna, EGU2013-6304
  Liermann, A., Dunai, T., Binnie, S., Heinze, S., Dewald, A., Victor, P., González, G.
  
• (2013): Uplift Record for Morro-Mejillones in Northern Chile with Evidence for Recent Change in Vertical Rates. AGU 2013 Fall Meeting, San Francisco, California
  Liermann, A., Dunai, T.J., Binnie, S.A., Heinze, S., Dewald, A., Victor, P., González, G., Bolten, A.
  
• (2015): Extension induced uplift in areas of low plate coupling: Mejillones Peninsula, northern Chile; GSGS Conference (2015)
  Liermann, A., Dunai, T., Binnie, S., Heinze, S., Dewald, A., Victor, P., González, G.
  
• (2016): Accelerated late Quaternary uplift revealed by 10Be exposure dating of marine terraces, Mejillones Peninsula, northern Chile. Quaternary Geochronology, 36, p. 12-27
  Binnie, A., Dunai, T.J., Binnie, S.A., Victor, P., González, G., Bolten, A.
  
• (2017): Effects of earth surface processes on exposure age distributions of marine terraces: insights from measurements and numerical modeling. The 14th International Conference on Accelerator Mass Spectrometry, Ottawa, Canada
  Binnie, A., Binnie, S. A., Parteli, E.J., Dunai, T.J.