Records of Climate and Paleoceanographic Variability during the Mid-Pleistocene Transition in the Pacific Ocean

Abstract

Paleoclimatic proxies from sedimentary marine sequences often record orbital frequencies (eccentricity, obliquity, and precession) and reveal the effects of insolation on environmental processes. During Pleistocene an important transition occurred in the time interval between 1.25 and 0.7 Ma, the so called Mid-Pleistocene Transition (MPT; Clark et al., 2006) that marked the passage from glacial cycles with 41 to 100-kyr rhythm. In the southwestern Pacific Ocean this transition reflects in paleoceanographic changes as the case east of New Zealand in correspondence of the northward flow of the Deep Western Boundary Current (DWBC). Many studies show evidences of the MPT by the use of proxies dependent on bulk and magnetic sediment grain-size and which provide qualitative information on variations in the strength of the deep Pacific Ocean inflow, possibly directly related to fluctuations of Antarctic Bottom Water production. Many works have been performed about these topics which revealed the importance to improve and enhance the knowledge through future researches.