Ar Dating of Near-Surface Faulting

9980459韧性剪切带的放射性测年已经彻底改变了对断层演化和地壳深部过程的理解，然而，放射性测年方法对脆性、近地表断层的测年还没有得到普遍利用，因为有几个因素使得数据的解释更加困难。 在近地表条件下的主要问题之一是矿物相的存在，这是碎屑（初级）和自生（次级）的起源。 因此，对这些岩石进行放射性测年通常会得出一个反映原生和次生粘土形成事件混合的“年龄”。 该项目将使用这种混合源年龄谱沿着方法学来确定碎屑相与自生相的百分比，以计算自生端元年龄。 结果应该完善这种方法，并提供初步的现场应用，几个重要的浅层故障。

9980459HallRadiometric dating of ductile shear zones has revolutionized understanding of fault evolution and deep-crustal processes, however use of radiometric methods to date brittle, near surface faulting has not been generally utilized, as several factors make the interpretation of the data much more problematic. One of the major problems at near-surface conditions is the presence of mineral phases that are both detrital (primary) and authigenic (secondary) in origin. Therefore, radiometric dating of such rocks typically results in an "age" that reflects a mixture of primary and secondary clay forming events. This project will use such mixed-source age spectra along with methodology to determine the percentages of detrital vs. authigenic phases to calculate the authigenic end member age. Results should refine this approach and provide preliminary field applications to several important shallow-level faults.