PROGRESS OF ENVIRONMENTAL TRACING USING MULTI-NUCLIDES IN IEECAS: A MEMORY FOR OUR FOREVER FRIEND PROF. S. PORTER

Prof. S. Porter was a famous scientist in Quaternary sciences. He has always encouraged us to carry out interdisciplinary and innovative studies since our collaborations in the late 1980s. With his guidance, great progress in environmental tracing using radionuclides of ¹⁴C and ¹⁰Be have been made in the past decades, including (1)through reliable ¹⁴C dating and high-resolution proxy measurements, our group were the earliest to identify the contribution of ENSO in precipitation variability of YD of Asian monsoon, and prove the synchronism of Holocene East Asian monsoon variations and North Atlantic drift-ice tracers, revealing the important influence exerted on Asian monsoon by high and low latitude climate interactions; (2) the “Mean Value Concept” was recently proposed and applied in the ¹⁴C data processing to overcome the old carbon “reservoir effect” correction in Lake Qinghai sediments, which help us to derive reliable ¹⁴C chronology and the robust geological record of meltwater events in this region as suggested by Porter before; and (3)we have mathematically disentangled geomagnetic field and precipitation signals in chines loess ¹⁰Be, of which has been traditionally believed impossible due to the mixture of ¹⁰Be from different sources. As a result, the high resolution geomagnetic field intensity record over 130 ka has been firstly reconstructed, and the exact horizons of Laschamp and Blake excursions in loess have been traced. Meanwhile, the loess ¹⁰Be-based Monsoon paleo-rainfall record over the 130ka is also quantitatively recovered, and the Inter-Hemispheric(NS) insolation gradient forcing on the Asian monsoon precipitation anomaly during the MIS 3 are proposed. The most striking work using ¹⁰Be is that we firstly confirm that the timing of Brunhes-Matuyama (B/M) reversal in loess was synchronous with that of marine sediments, which settling the long debates on the asynchronous phenomena of B/M reversal recorded in terrestrial and marine sediments. The progress on multi-nuclides tracing open up the new direction in environmental studies from terrestrial archives, complementing marine and ice-core records. It was also to address our forever memory for Prof. S. Porter, especially for his valuable suggestions on aforementioned tracing studies.