Haisheng Liu

Natural thermoluminescence (TL) from the core of MD81349 marine calcareous biological ooze samples in the Ninetyeast Ridge of the equatorial northeast Indian Ocean and from the core of IODP306-U1312B in the high latitudes of the North Atlantic Ocean was studied. The spurious TL intensity of 395 °C at its peak is dose independent when the heating rate is 6 °C/s in a nitrogen atmosphere. TL signals have exhibited a significant correlation with the marine isotope stages (MIS) in the two oceans since the mid-Pleistocene era. High TL intensity corresponds to a negative δ¹⁸O in the interglacial stages, and low TL intensity corresponds to a positive δ¹⁸O in the glacial stages. The TL of both cores from the two oceans reveal that global climate has experienced eight cold and warm cycles since the mid-Pleistocene era. In this study, a single-frequency spectrum analysis of the MD81349 and U1312B TL cores in the last 300 ka is performed. Near the equator of the northeast Indian Ocean, the short cycles of 38 ka and 5 ka are more significant, while the cycle of 8 ka is more significant in the North Atlantic Ocean. In addition, a correlation analysis shows that the TL has a significant positive correlation with the trace element ¹³⁵Ba and a significant negative correlation with ⁴⁷Ti. The impurity ions (e.g., Ba²⁺, Mn²⁺ and Ti²⁺) doped in carbonate act as activators and suppressants, respectively. A time series of the TL of the calcareous biological ooze tests provide an important record of climate change. The source of the TL signal is also discussed.

Natural Thermoluminescence (TL) from the core of MD81349 marine calcareous biological ooze samples in the ninetyeast ridge of the equatorial northeast Indian Ocean and samples from the core of IODP306-U1312B in the high latitudes of the North Atlantic Ocean was studied. The spurious TL intensity of 395 °C peak is dose independent when the heating rate is 6 °C/s in a nitrogen atmosphere . TL signals exhibit a significant correlation on the marine isotope stages (MIS) at the two oceans since the mid-Pleistocene. High TL intensity corresponds to a negative δ18O in the interglacial stages, and low TL intensity corresponds to a positive δ18O in the glacial stages. TL of both cores at the two oceans reveal that the global climate has experienced eight cold and warm cycles since the mid-Pleistocene. Single-frequency spectrum analysis of MD81349 and U1312 TL in the last 300 ka was performed.Near the equator of the Northeast Indian Ocean，it is more significant that the short cycle of 38 ka and 5 ka while it is more significant that the cycle of 8 ka at the North Atlantic.In addition, correlation analysis shows that the TL has a significant positive correlation with trace elements 135Ba, a significant negative correlation with 47Ti. The impurity ions (e.g. Ba2+, Mn2+ and Ti2+) doped in carbonate are acting as activators and suppressants respectively.Time series of the TL of calcareous biological ooze tests provide an important record of climate change. The source of TL signal is also discussed.