Archive

Wed 19th July @ noon, Rm 312.222 Abstract: During hyper-velocity meteorite impacts, minerals may deform in unique manners, known as shock metamorphism. The two most commonly used U – Pb geochronometers, the accessory minerals zircon and monazite, respond in distinct ways to shock, including developing mechanical twins, various crystal-plastic deformation features and in the case of zircon […]

Wed 12th July @ noon, Rm 312.222 Abstract: Cristobalite is a low-P, high-T polymorph of crystalline silica (SiO2). Despite having a nominal stability field far outside the conditions that exist in crustal magma bodies, it forms and persists as metastable vapour-phase crystals in the pores of many volcanic rocks. Interest in volcanic cristobalite has been driven by: […]

Wed 5th July @ noon, Rm 312.222 Abstract: In various shocked meteorites, low-pressure silica polymorph α-cristobalite is commonly found in close spatial relation with the densest known SiO2 polymorph seifertite, which is stable above ~80 GPa. We demonstrate that under hydrostatic pressure a-cristobalite remains untransformed up to at least 15 GPa. In quasi-hydrostatic experiments, above 11GPa cristobalite […]

Wed 21st June @ noon, Rm 312.222 Abstract: To develop a comprehensive understanding of geological processes a multidisciplinary approach much be utilized. To provide insights on the origin and duration models of LIPs generation, this research focus’ on three Continental Flood Basalts (CFB) located throughout the Southern Hemisphere; the ca. 511 Ma Kalkarindji CFB Province located in […]

Wed 7th June @ noon, Rm 312.222 Abstract: The formation of impact craters is a highly dynamic and complex process that subjects the impacted target rocks to numerous types of deformation mechanisms. Understanding and interpreting these styles of micro-, meso- and macroscale deformation has proved itself challenging for the field of structural geology. The presentation introduces to […]

Wed 24th May @ noon, Rm 312.222  Abstract: Although the source of metals for porphyry deposit systems is still debated, large magma chambers are commonly assumed to develop underneath the porphyry deposits. Systematic investigations of mineral texture and chemistry, generally focused on plagioclase, have been widely used to describe the processes occurring in the magma chamber of […]

Wed 3rd May @ noon, Rm 312.222  Abstract: Field, geochronological, isotopic and geophysical studies do not support plate tectonic models for subduction and arc accretion in Archaean granite-greenstone terrains. Geophysical data suggest Neoarchaean granite-greenstone sequences of the southern Superior Province in Canada formed during rifting of an older, composite Superior I craton and not as a series […]

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 […]

Wed 16th November @ noon, Rm 312.222  Abstract Following the breakup of Australia from Greater India in the Early Cretaceous, the North West Shelf of Australia (NWS) evolved as a passive margin. The combination of a wide continental shelf and relatively limited clastic influx resulted in the progradation of carbonate strata, and these deposits  constitute excellent […]

Wed 2nd November @ 12:00 pm, Rm 312.222  Earth was hotter in its early history, though few observations exist on the cooling rate of the bulk Earth. We demonstrate that rates of true polar wander–wholesale rotation of mantle and crust around the core–have significantly decreased over the past three billion years. As true polar wander is […]