%0 Generic %A A. Forster, M. %A Armstrong, R. %A Kohn, B. %A S. Lister, G. %A A. Cottam, M. %A Suggate, S. %D 2015 %T Highly retentive core domains in K-feldspar and their implications for 40Ar/39Ar thermochronology illustrated by determining the cooling curve for the Capoas Granite, Palawan, The Philippines %U https://tandf.figshare.com/articles/dataset/Highly_retentive_core_domains_in_K_feldspar_and_their_implications_for_sup_40_sup_Ar_sup_39_sup_Ar_thermochronology_illustrated_by_determining_the_cooling_curve_for_the_Capoas_Granite_Palawan_The_Philippines/1623171 %R 10.6084/m9.figshare.1623171.v1 %2 https://ndownloader.figshare.com/files/2606397 %2 https://ndownloader.figshare.com/files/2606398 %K Palawan %K ma %K thermochronology %K cooling rate %K closure temperatures %K core domains %K argon diffusion %K vacuo yields Arrhenius data %K Miocene Capoas Granite %X

K-feldspar from the late Miocene Capoas Granite on Palawan in The Philippines appears to contain highly retentive diffusion domains that are closed to argon diffusion at near-solidus temperatures during cooling of this ∼7 km-diameter pluton. This is an important result, for K-feldspar is commonly considered not retentive in terms of its ability to retain argon. Closure temperatures for argon diffusion in K-feldspars are routinely claimed to be in the range ∼150–400°C but the release of 39Ar from irradiated K-feldspar during furnace step-heating experiments in vacuo yields Arrhenius data that imply the existence of highly retentive core domains, with inferred closure temperatures that can exceed ∼500–700°C. These high closure temperatures from the Capoas Granite K-feldspar are consistent with the coincidence of 40Ar/39Ar ages with U–Pb zircon ages at ca 13.5 ± 0.2 Ma. The cooling rate then accelerated, but the rate of change had considerably slowed by ca 12 Ma. Low-temperature (U–Th)/He thermochronology shows that the cooling rate once again accelerated at ca 11 Ma, perhaps owing to renewed tectonic activity.

%I Taylor & Francis