(mil ank’ ō vich) Climate cycles produced by variations in the Earth’s orbit and consequent variations in the amount of solar radiation the Earth receives. Cycles resulting from variations in the Earth’s orientation, precession, and orbit eccentricity that presumably affect insolation and hence climate, and thus produce periodicity in climate, sedimentation, and eustasy. Orbital perturbations (precession and eccentricity variations) have periods of about 413, 123, 95, 41, and 21 ka. The periods 100, 41, 23, and 19 ka can also be seen in oxygen isotope and other data. Van Houten cycles of about 400, 100, 21 ka determined from sediment repetitions in the Newark Basin roughly correlate with Milankovitch cycles. Named for Milutin Milankovitch, a Serbian mathematician. See Figures M-13 and S-5, Arthur and Garrison (1986), or Berger et al. (1984).