Cause-and-effect of plate motion and crustal thickening using time-series analysis and data analytics
- 1. Centre for Ore Deposit and Earth Sciences (CODES), University of Tasmania, alex.farrar@utas.ediu.au
- 2. Centre for Ore Deposit and Earth Sciences (CODES), University of Tasmania
Description
Cordilleran orogenic systems, such as the Andes, form adjacent to oceanic-continental convergent margins due to compressional and mass transfer events, widely accepted to result from plate tectonic processes. The same tectonic processes are intrinsically related to the formation of porphyry Cu and Au deposits. However, a formal, data- driven approach that assesses the causal relationship between plate convergence parameters and orogenic uplift indicators has not been assessed. We conduct time-series and statistical analysis of published central Andean orogenic proxies since the late Cretaceous. We find that orogenic proxies statistically correlate, in some cases with temporal causality. Statistical analysis of five plate motion models for Nazca-Farallon - South America plate convergence reveals the variability between different published plate tectonic motion models. Granger causality analysis of plate convergence motion models with orogenic proxies demonstrate that changes to convergence rate precede flat slab subduction; oscillations of tectonic stress and crustal thickening guides precede convergence rate changes, and strong bi-directional causality exists between convergence rate fluctuations and Andean exhumation and paleoelevation uplift proxies. Convergence obliquity fluctuations exhibit a causal relationship on tectonic stress and crustal thickening. These data-driven results advance our understanding of how plate convergence and orogenic processes in the central Andes interact and provide insight into tectonic preconditioning processes that are required for the formation of giant porphyry ore deposits.
Notes
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AEGC_2023_ID039.pdf
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