If the concentration of argon-40 is almost zero, then the rock was formed recently.If it is high relative to the amount of potassium-40 present, then the rock is old.
Here we examine the effect of mantle upwelling through a study of Quaternary uplift along the coast of Angola. Potassium-argon dating is a method for estimating the age of volcanic rocks by measuring the ratio of potassium-40 to argon-40 present.The method is based on the fact that the potassium-40 isotope of potassium decays over time to form argon-40. cookies, tags, and tracking settings to store information that help give you the very best browsing experience.To understand more about cookies, tags, and tracking, see our Privacy Statement1 Issue per year IMPACT FACTOR increased in 2015: 2.038Rank 12 out of 54 in category Paleontology and 70 out of 184 in Geosciences, Multidisciplinary in the 2015 Thomson Reuters Journal Citation Report/Science Edition SCImago Journal Rank (SJR) 2015: 1.027Source Normalized Impact per Paper (SNIP) 2015: 0.880Impact per Publication (IPP) 2015: 1.600 *Prices in US$ apply to orders placed in the Americas only. performed the fieldwork and undertook all sample collection; J.-L. performed the radiocarbon calibrations and age modelling; R. In this paper we address whether the absence of earthquake surface ruptures and fault scarps can be used to infer the inactivity of faults in tectonically active regions.This issue is not only of interest for understanding the distribution of tectonic deformation, but also for assessing the seismic hazard of a region, which typically relies on the mapping of faults that cut young (Holocene/late Pleistocene) alluvial cover.Within arid continental interiors single earthquake scarps can be preserved for thousands of years, and yet the interval between surface ruptures on faults in these regions may be much longer, such that the lack of evidence for surface faulting in the morphology may not preclude activity on those faults.In this study we investigate the 50 km-long ‘Toraigyr’ thrust fault in the northern Tien Shan.