Wed 22nd February @ 12:00 pm, Rm 307.101:LT 

Formation of calcite veins and breccias in association with CO2 degassing is common along plate boundary faults in Turkey and crustal-scale intra-continental faults in central Australia.  In this presentation, I will present a precisely-dated late Quaternary record using U-series dating to investigate the timing of vein formation and to relate it to tectonic and/or climatic processes. In southwest Turkey, vein formation is focused during cold/dry climate periods. It is proposed that during wet/warm climate periods crustal and mantle-derived CO2 is transferred to the surface where it passively degassed from springs when meteoric water circulation is enhanced. By contrast, during phases when groundwater is limited, CO2 builds- up in sealed reservoirs and degassing is associated largely with rupture events. While regional tectonics is the ultimate driver of fault activity, climate-driven near surface hydrological changes may have played an important role in modulating CO2-rich fluid circulation. In south-central Australia, late Quaternary to Recent fault-controlled mantle-derived CO2 degassing occur in association with travertine vein deposits of which U-series ages cluster every ~3-4 ka since 26 ka. A neotectonic model is discussed in which recent stress field, heat flow and lithospheric structure in central Australia reactivated a number of steeply dipping Neoproterozoic faults, growing into a crustal/lithospheric-scale structure.

Short bio:

Tonguç Uysal is a geoscientist focussing on isotopic dating and tracing of hydrothermal/geothermal systems and thermal histories of sedimentary basins as well as active fault systems. Tonguc has recently joined CSIRO, after he had been a Marie Curie Research Scientist in Turkey and Research Fellow at the University of Queensland (UQ). Tonguc has a BSc (Hons) Degree from Istanbul Technical University, Master’s Degree from Aachen University in Germany, and PhD from UQ in 1999.