Evaluations of the anoxic conditions in the oceans that contribute to the accumulation of organic-rich source rocks, have become extremely valuable for examining past climates, since the oxygen-free conditions on the sea floor can lead to virtually undisturbed sediment sequences that preserves high-frequency climate information. Cariaco Basin off northern Venezuela has produced one of the most valuable records of tropical climate history and abrupt climate change in the late Pleistocene. Evaluations on the abrupt climate change of the magnitude in the ice cores, led to a sweeping reevaluation of the processes that caused the major changes in the climate system. Presently the explanation of these changes evolves around estimating freshwater input to the subpolar North Atlantic and its effects on heat transport into the region through interruption of the density-driven meridional overturning of the Atlantic.