GREATER NORTH CHINA INITIATIVE (GNCI): CENOZOIC GEODYNAMICS, CLIMATIC EVOLUTION, AND GEOLOGICAL HAZARDS A whitepaper of scientific rationale and strategic plans for cooperative research between the IPACES and Chinese geosciences community 2005 GNCI Whitepaper - 2 - List of the GNCI whitepaper drafting group CHEN Yongshun Peking University FENG Xiahong Dartmouth College, USA GE Shemin University of Colorado, USA LI Zhengziang University of Western Australia, Australia LIU Mian University of Missouri-Columbia, USA NIU Yaoling University of Durham, UK SHEN Zhengkang State Seismological Bureau, China SONG Xiaodong University of Illinois-Urbana Champaign, USA WANY Yang Florida State University, USA WU Zhongliang State Seismological Bureau, China YIN An University of California-Los Angles, USA ZHANG Youxue University of Michigan-Ann Arbor, USA ZHAO Dapeng Ehime University, Japan ZHAO Meixun Dartmouth College, USA Special Acknowledgement: This document is produced from extensive discussion at a number of NCP (North China Project) workshops. We thank the National Science Foundation of China (NSFC) and Drs. Chai Yucheng, Yao Yupeng, and Yu Sheng for their support and their enthusiasm in this endeavor. Many colleagues in China contributed significantly to this document in various aspects of its development. In particular, we thank Chen Yong, Chen Xiaofei, Chen Bin, Gao Rui, He Jiankuan, Lu Huafu, Li Yanxin, Liu Qiyuan, Liu Futian, Ren Jianye, Shi Yaolin, Wei Wenbao, Wu Fuyuan, Wang Chunrong, Wang Lianshu, Wang Chengshan, Xu Yigang, Xu Xiwei, Zan Shaoxian, Zhang Peizhen, Zheng Tianyu, Zhang Yueqiao, Zhou Yaoqi for their valuable contributions. GNCI Whitepaper - 3 - Executive Summary The Great North China Initiative is a multifaceted research plan aimed at a holistic understanding of the Cenozoic evolution of the Earth systems in the Greater North China region (GNC). The GNC is chosen because (1) it hosts the most vital industrial, commercial, residential, and political centers of China; (2) it is one of the most geologically active continental regions in the world, with frequent and devastating earthquakes, floods, draughts, dust storms and other natural hazards; (3) it has a delicate ecosystem that is sensitive to the dynamic interplays among lithosphere, hydrosphere, atmosphere, and biosphere; (4) it is geologically the best studied regions in China where abundant geological and geophysical data provide a firm foundation for the proposed Earth system studies. This research plan identifies some of the fundamental questions regarding the Cenozoic geodynamics of the Earth systems in the GNC, and outlines the required interdisciplinary approaches to address these questions. One focus area of this research plan is active crustal deformation and earthquakes – the GNC has the most active intracontinental seismicity in the world. Another focus area is asthenosphere-lithosphere interactions. In particular, effort is called to understand the mantle processes responsible for the thermal thinning of the GNC lithosphere since late Mesozoic, and the diffuse intraplate igneous activity throughout the Cenozoic. A third focus area is paleoclimate change in late Cenozoic and its relationship with tectonics, paleoecology, and hydrology. All these processes are integral parts of the system dynamics involving mantle flow, lithosphere deformation, air and water circulation, and bio-activity, hence requires cross-disciplinary approaches. In the past few years, the IPACES (International Professionals for the Advancement of Chinese Earth Sciences), with support from the National Science Foundation of China (NSFC), has conducted extensive discussions among its members and with scientists in China through a number of workshops. We are convinced that the Great North China Initiative (GNCI) will have a great impact on sustainable development of China in the next decade, while the cutting-edge integrated research in this plan will propel Chinese Earth Sciences to an international leadership position. GNCI Whitepaper - 4 - Table of Content 1. Introduction ……………………………………………………………………….5 1.1. Why North China? …………………………………………………………...5 1.2. Integrated Investigation of the GNC …………………………………………6 2. Lithospheric Deformation ………………………………………………………...8 2.1. Geographic Division of the GNC …………………………………………….8 2.2. Tectonic Development of GNC ………………………………………………8 2.3. Tectonic Boundary Conditions of the GNC ………………………………….11 2.4. Active Deformation …………………………………………………………..11 2.5. Major Questions……… …………..………………………………………….15 2.6. Recommendations …….……………..……………………………………….16 3. Mantle Processes ……………………………………………………………….....17 3.1. Seismic Velocity Structure …………………………………………………...17 3.2. Mesozoic to Cenozoic Modification of Lithospheric Mantle ………………..19 3.3. Cenozoic Volcanism in the Greater North China …………………………….21 3.4. Previous Studies on Cenozoic Volcanism in the GNC ………………………24 3.5. Major Questions ……………………………………………………………...28 3.6. Possible Research Directions ...………………………………………………29 4. Climate, Water, and Environment ………………………………………………...34 4.1. Introduction …………………………………………………………………..34 4.2. Paleoclimate ………………………………………………………………….35 4.3. Paleoecology……………………………………………………………...…..37 4.4. Hydrological Research ……………………………………………………….40 5. Integration ………………………………………………………………………...42 5.1. Climate Change, Surface Processes, and Tectonics ………………………….42 5.2. Crustal Stress, Earthquake Physics, and Hydrologic Processes …………...…43 6. Project Management ………………………………………………………...…….43 GNCI Whitepaper - 5 - 1. Introduction 1.1. Why North China? The IPACES (International Professionals for the Advancement of Chinese Earth Sciences – www.ipaces.org) posted two questions when preparing this document: (1) What kind of research would have the greatest impact on sustainable development of China in the next decade? (2) What is the most effective research plan that would propel Chinese Earth Sciences to an international leadership position? After extensive discussion among the IPACES members and with geoscientists in China, we identify the Greater North China (GNC) region as the most promising target for addressing the above questions. Our decision is based on the following. (1) The GNC covers about one-quarter of China’s territory (Fig. 1) and hosts the most vital industrial, commercial, residential, and political centers of the nation. This region is one of the most populated areas in China. Understanding its geologic setting is a prerequisite for making future strategic plans for the overall sustainable development of China. (2) The GNC is one of the most geologically dynamic settings in the world, as indicated by the frequent occurrence of devastating earthquakes, floods, draughts, and dust storms. These natural hazards have enormous impacts on both the economy of China and the quality of life in the region. Remediation of these hazards requires a complete knowledge of geodynamic, climatic, and land-surface processes as well as the interactions among them. (3) The GNC has a very delicate ecosystem and is long known for the lack of water resources. As the storitivity of any substantial aquifers depends critically on the climatic conditions, it is prudent to obtain paleoclimatic data that allow establishment of quantitative models to make specific predictions on the trend of climate variations at centennial to millennial scales. The models can provide a better guide for future planning of large urban centers whose survival will critically depend on the availability of water resources. (4) GNC is a key area for testing many prominent geological hypotheses ranging from the nature of continental deformation to interactions between tectonics and climate changes. Because of this, GNC has become the focus of many international research groups in recent years. This provides a unique opportunity to the Chinese Earth Science community to showcase their scientific achievements in the international arena. (5) A large amount of geological and geophysical data in the GNC region has accumulated over the past century. These data sets give the Chinese Earth scientists a unique advantage as the international geosciences community becomes increasingly more interested in understanding diffuse continental deformation in Asia and the coupled tectonics-climate processes. (6) Both the IPACES and Chinese Earth Sciences community have extensive expertise and research experience for the studies of GNC. Many of them already have a strong track record in publications on regional climate variations, tectonics, geochemistry, and geophysics. With a coordinated integration of diverse research areas and GNCI Whitepaper - 6 - approaches, the Chinese Earth Science community is poised to take a prominent position in the regional studies of eastern Asian geology. Fig. 1. Geological Map of Asia. Red area outlines the Greater North China region 1.2. Integrated Investigation of the GNC In the past four decades, several major shifts of research focuses have occurred in Earth Sciences. The advent of the plate-tectonics theory in the 1960’s provides a simple kinematic description of lithospheric deformation that is most applicable to the oceanic regions [e.g., Morgan and McKenzie, 1965]. Research in the 1970’s and early 1980’s had focused on testing predictions of plate tectonics [e.g., Ernst, 1971; Dickinson, 1973] and applying the theory to reconstructing the history of ancient mountain belts [e.g., Dewey and Burke, 1973; Sengor, 1985]. Since the mid-1980’s, research on continental dynamics has flourished, which is mainly stimulated