Figure F54. (A, B) Downhole spectral gamma-ray data for Th, and (C) preliminary power spectrum of Th between 334 and 422 mbsf using both the Blackman-Tukey (solid line) and maximum entropy (dashed line) methods. For the Blackman-Tukey method, 95% confidence is 0.49 < DP/P < 3.08.