Denis-Didier Rousseau

(Environmental Research and Teaching Institute, CERES, Paris, France)

 

Learning about Professor Liu's death has been a tremendous earthquake, which shocked my brain! I received so numerous aftermaths after this sad news because he was a colleague, a great scientist, but also a friend. Something terrible happened hurting this smiling giant forever. This was not possible, not him, not yet as he always looked so young, so active…so impressive! Even if prepared to such dramatic issue, because knowing how sick he was, I always asked some news about him and his health, I tried to remain confident that a miracle could occur. Having met him during the Humboldt conference I had been very happy to see him receiving the Humboldt award from the European Geosciences Union not only because he deserved such recognition but also because I was among those who nominated him, then seeing him attending the ceremony and receiving this award from a foreign scientific union, one more award, was a great delight. Once more, he was smiling, with his so particular smile he was always having on his face, the last one I saw from him and will never forget.

A small and attractive person, but a scientific giant and a good friend passed away one year ago. And I miss him.

I have been asked to write a memory paper about Professor Liu, and I consider such proposal a great honor. Then instead to relating a long, to long story, I will prefer use flashbacks about points I consider important and for some of them personal. Speaking about Prof. Liu's always reminds me the first time I met him during an international field excursion of the INQUA loess commission held in Normandy in 1987? Being a young scientist, I was attending the field trip and associated scientific meeting to present my work on the study of terrestrial mollusks from the French sequence of Achenheim. My very good friend Dr. Jean-Pierre Lautridou organized the excursion, a very active loess scientists who taught me a lot and active member of the former INQUA Commission on Loess. So during this excursion, I had the opportunity to discuss with professor Liu about the potential of terrestrial mollusks as very good and reliable indices of past environments and climate. I knew a little about Chinese loess sequences, very few at that time. I turned fascinated after discussing with Prof Liu's and knew this was the place I should come. Prof Liu was aware of the interest of mollusk as a precious archive for understanding Quaternary climate changes. So during this excursion after several exchanges, Prof Liu proposed me to come to China and work on Chinese snails preserved in the sequences of the Loess Plateau. I guess, retrospectively, that his knowledge of the potential sequences to be investigated on the loess plateau would provide a very interesting and challenging field of new studies knowing the work of Professor Chen Deniu on continental mollusks. I was sharing this interest because of learning new material and also environmental conditions, seeing a wonderful opportunity to see these famous and fabulous records.

Before being able to go to China, I have had the opportunity to go to Lamont to work with Dr. George Kukla another great loess scientist another scientific giant, another friend of Professor Liu. There I learned a lot about paleoclimatology, about US loess deposits but we also discussed about Chinese loess sequences and also about some anecdotes when Prof Liu visited Lamont that I am sure George will speak about.  I could freely access George's important literature and back to France in 1992, contacted again Prof; Liu intending to apply to the CNRS-CAS scientific exchange call for proposal. Prof Liu agreed and introduced me to a scientist recently arrived to his lab from Shanghai, a scientist who is now professor and also a very good friend and collaborator, Professor Wu Naiqin. This was the start of a very long story with China, Chinese loess Plateau, with Luochuan sequence. Since then I have tried to come regularly to China to continue this collaboration and I was always willing to exchange if possible with Prof Liu about our common results from Luochuan but also about my research and lab directorship in Montpellier. What I learned from him among all these prestigious colleagues I have been fortunate to collaborate with, was that transmitting ones knowledge to the younger generation is not only a duty, this is a gift that is given to us and that one must not jeopardize. This is the reason why I always appreciated having Chinese students attending field work with me. I know that Prof; Liu appreciated this and I always took the opportunity to speak about these young scientists growing slowly but surely in his lab.

I sincerely strongly respected Prof Liu because of his wide interest to so various geoscientific topics. This is a great lesson to young scientists including myself that we must keep in mind. Remain interested by different subjects and topics, stay aware about new discoveries, new developments in other field research. Stay awake to novelties and news! Professor Liu was an example in such aspect and this is something I always try to transmit my students to keeping their eyes opened, rejecting narrow minded mentality. What a precious gift that one must preserve and considering professor's Liu career, being able to handle so various topics required a gifted person to accomplish all that.

I also remember the day of Professor Liu's election as new INQUA president, at the end of the INQUA congress held in Beijing in 1991. I remember this enormous explosion of joy that this recognition generated. This was very really impressive and an evident great accomplishment. Then I was pleased to organize official and unofficial messages for his 90th birthday when I was at that time vice-president of INQUA. This has been a great experience to connect so many colleagues and national committees to suggest them to send a message to express their recognition, friendship to this great scientist. This was a real pleasure to do so and I am glad that my colleagues replied positively to my request.

Having professor Liu's granted so many prestigious awards and prizes was first of all a personal recognition that he deserved enormously. He was nominated in the first Science Steering Committee of INGP PAGES program on paleoclimatology working with prestigious fellow scientists. This was another way also he contributed to attract the attention of local politicians and officers of funding agencies towards geosciences world. His scientific aura could then highlight geosciences research, and perhaps more specifically loess studies, as a major scientific field, a key factor in understanding our past, for a better prediction of our near future.

Prof Liu has been fortunate to have numerous students who are now standing on his tracks, taking over, and no doubt that this scientific monument, one of Chinese main lighthouse, will never be forgotten. He remains forever living as he seeded during his lifetime enough promising scientists who already are now solid and established colleagues, perpetuating then his spirit.

I have been fortunate to meet, work and have friendship with numerous monuments of paleoclimatology, and Professor Liu definitively stays in my Pantheon.