第四纪冰冻圈——全球变化长尺度研究

Quaternary Cryosphere—Study on Global Change in Long Terms

        周尚哲(华南师范大学 广州 510631)
        赵井东(中国科学院西北生态环境资源研究院 兰州 730000)
        王杰(兰州大学 兰州 730000)
        许刘兵(华南师范大学 广州 510631)
        崔建新(陕西师范大学 西安 710119)
        欧先交(嘉应学院 梅州 514015)
        谢金明(兰州大学 兰州 730000)

         第四纪;冰冻圈演变;人类发展

        Quaternary;cryospheric change;human development

        第四纪是以大冰期为标志的最新地质历史时期。这个大冰期的基本特征是轨道尺度的冰期-间冰期交替及亚轨道尺度的冰阶-间冰阶变化。现在是比较温暖的间冰期，冰川只覆盖陆地面积的10%。而在冰期最盛时，冰川覆盖全球陆地面积的30%，冻土扩展，气候干旱，风沙盛行，海平面降低130-150 m，植被向低纬度收缩10o以上，垂直带谱下移1 000 m以上。冰期天文理论成功解释了冰期-间冰期循环周期问题，但还存在诸多挑战。第四纪也是古人类向现代人发展的时期。古人类诞生于东非，约200万年前曾向欧亚大陆有限扩散，但一直到了末次间冰期才大规模扩散；尤其在随后的末次冰期中，人类更是借助于大陆桥扩散到美洲和澳洲。新仙女木事件后，气候变暖，人类进入细石器时代并逐渐过渡到农业社会。工业革命开始，人类发展深刻影响到了地球的自然进程，导致全球变暖，预示着一个"人类纪"的到来。

        The Quaternary is marked by the Great Ice Age. The basic characteristics of this great ice age are the alternating of glacialinterglacial period in orbital scale and changes of stadial-interstadial in suborbital scale. Present is a relatively warm interglacial period, with glaciers covering only 10% of the land area. At the glacial maximum, glaciers covered about 30% of the global land area, permafrost spread, climate was dry with prevalence of dust, sea level reduced 130-150 m, vegetation contracted to low latitudes more than 10°, and the vertical band spectrum moved down more than 1 000 m. The astronomic theory of ice ages has successfully explained the glacial-interglacial cycles, however, there are still a lot of problems to need studies in detail. Quaternary is also the period of ancient human development. Ancient human was born in East Africa and spread to Eurasia only on a limited scale about 2 Ma ago. The spread on a large scale started during the last interglacial and spread to America and Australia by means of land bridges during Last Glaciation Maximum (LGM). After the younger Dryas, the climate became warm and the human entered the Neolithic Period and gradually transited to the agricultural society. After the Industrial Revolution, human development has been profoundly affecting the natural process of the Earth, leading to global warming, heralding the arrival of an "Anthropocene".