a: Nearby Twin Lakes production rate used (4.09 +/- 0.30 at/g/SiO2/yr).b: A density of 2.7 g cm-3 , std elv/pressure conditions, and the KNSTD standard were used for all samples.c: Isotope ratios were normalized to 10Be standards prepared by Nishiizumi et al. (2007) with a value of 2.85 x 10-12 and using a 10Be half life of 1.36 x 106 years.d: Uncertainties are reported at the 1σ confidence level. A denundation rate of 0 mm/a is used in the age calculation. e: Propagated uncertainities include error in the blank, carrier mass (1%), and counting statistics.f: Beryllium-10 model ages were calculated with the CREP online calculator, (Martin et al., 2016; http://crep.crpg.cnrs-nancy.fr/#/).