highly significantP = 0.005
Astrochronologic evaluation of the clast abundance data via the TimeOpt method ( 60 , 61 ) identifies an optimal sedimentation rate of 60.12 cm/kyr that is highly significant ( r 2 opt = 0.399; P = 0.005), based on 2000 Monte Carlo simulations using power law surrogates (see Materials and Methods and Supplementary Text).