Heinrich layer in Antarctic marine sediments and its significance to global changes

Environmental magnetism: Principles and applications

“…Despite the potential for rock magnetic techniques to identify IRD, we are aware of only a handful of studies where environmental magnetic parameters (especially χ ) have been used to study Antarctic IRD [e.g., Hou et al , 1998; Brachfeld et al , 2002; Kanfoush et al , 2002; Pirrung et al , 2002; Venuti et al , 2011]. Warm waters surrounded Antarctica throughout most of the Paleogene [ Ehrmann and Mackensen , 1992], which prevented long‐distance transport of IRD at those times, while the strong influence of currents complicates interpretation of Quaternary IRD layers [ Pirrung et al , 2002].…”

“…Warm waters surrounded Antarctica throughout most of the Paleogene [ Ehrmann and Mackensen , 1992], which prevented long‐distance transport of IRD at those times, while the strong influence of currents complicates interpretation of Quaternary IRD layers [ Pirrung et al , 2002]. Regardless, in many cases, Antarctic IRD layers are characterized, like Quaternary North Atlantic IRD layers, by high χ values [ Kanfoush et al , 2002; Pirrung et al , 2002; Venuti et al , 2011] due to enhanced concentrations of magnetic minerals with respect to background sediments [ Hou et al , 1998].…”

“…This is important because correlation between these marine sediments and ice core records enables establishment of detailed age models for sediments that are otherwise difficult to date [ Pugh et al , 2009]. However, the magnetic susceptibility signal of other peri‐Antarctic marine sediments has been linked mainly to IRD material [ Hou et al , 1998; Kanfoush et al , 2002; Pirrung et al , 2002]. Unmixing IRD and dust signals is further complicated by reworking of peri‐Antarctic marine sediments by the Antarctic Circumpolar Current [ Parés et al , 2007; Mazaud et al , 2007, 2010; Hassold et al , 2009a, 2009b].…”

Youger Dryas and Heinrich events recorded by magnetic susceptibility of sediments from the central temperature area of Western Pacific Warm Pool

“…The samples selected for the studies of magnetostratigraphy and environmental magnetism in previous work were usually collected from the middle or high latitude areas [1][2][3] because the magnetic moment and magnetization state of magnetic minerals in these samples are relatively stable, thus easy to obtain the desired magnetic inclination (I ) and magnetic declination (D) and can provide reliable data for the division of magnetostratigraphy and drawing of magnetic environment information. But it is relatively difficult to obtain the desired magnetic inclination and magnetic declination from the samples in low-latitude areas, especially for the samples from the nearby of the earth's equator and magnetic equator, where their magnetic moment and magnetization state can be magnetized either positively or negatively, so few samples from these areas were used for magntostratigraphical study.…”

“…It is located at either the south of earth's equator or the south of magnetic equator, but the magnetic inclination of sediments in this core is similar to that of the marine sediments in middle-high latitude areas of the Northern Hemisphere, unlike the magnetic properties of sediments from the Antarctic sea area which appeared negative polarity when the sediments were magnetized positively or positive polarity when magnetized reversely [4] . With the deepening of study, the susceptibility was often used as an important proxy for palaeoclimatic cycles in the studies on environmagnetism and ice cycles of sediments from Antarctic [3] , mid-Atlantic [9] , the northwest Pacific [10] , and Southern Tibet [11] , China in recent years, implying directly or indirectly that there is a certain correlation between the susceptibility and palaeoclimate, but the mechanism is still unclear. Whether the sudden change of susceptibility of sediments is related to the climatic warm/cold variation or not?…”