The petrologic and petrochronologic record of progressive vs polyphase deformation: Opening the analytical toolbox

Recent advances in petrochronology: from dates to ages and rates of deep orogenic processes

“…This data is undoubtedly altered by preservation bias, due on the one hand to retrogression and polymetamorphism, as complex as the rocks are old Palin et al [2020], but also due to the erosion of the superficial parts of ancient orogenic wedges in which HP-LT relics are most often imbricated Willigers et al [2002]. The continual addition of older ages to the list of HP-LT metamorphic occurrences Palin et al [2020], Brown et al [2022] is likely evidence of such a preservation bias.…”

“…Multi-method studies in particular led to move petrochronology out of the M i /D i approach Oriolo et al [2022] and to extend the progressive approach to the interpretation of age patterns. The documentation of several age populations in the same rock or unit, favored by the large number of dates produced and their interpretation as ages on the basis of textures or geochemical signatures, yields different conclusions depending on the time scale on which these populations are distributed.…”

“…depth reached, an apparent burial rate (in km/Myr) characteristic of the incorporation of foreland basins into their related wedge. The compilation of available estimates Nicoli et al [2016] shows a secular decrease in the calculated maximum rates attributed to the gradual decrease in juvenile crust production as well as a decrease in the diversity of active orogenic processes Nicoli et al [2016], Palin et al [2020. The age difference between metamorphic peak and retrogression assemblages allows, together with the estimate of associated T conditions, to calculate cooling rates [in °C/Myr, Chowdhury et al, 2021, Brown et al, 2022 9].…”