【作者】 付淑清；

【导师】 李勇； 陈淑娥；

【作者基本信息】 长安大学 ， 古生物学与地层学， 2004， 硕士

【摘要】 天水地区是我国季风环境的敏感地带之一，也是我国最早进行农业耕作的地区之一。长期的农牧业发展，使得区内除部分山区以外天然植被已几乎荡然无存，仅见到少量的人工次生林，森林覆盖率极低，水土流失严重。因而深入研究天水地区近1万年以来的环境变迁及其社会影响，对于近代气候的预测及其制定正确的土地利用方式具有重要的意义。 对天水境内西北—东南方向上的三个全新世土壤剖面作了详细的地层学与土壤学研究，以2 cm为间距密集采样，并对所有样品进行了磁化率和粒度指标的测定与分析。通过对各指标环境指示意义的分析，探讨了该区全新世期间环境变迁的特点，同时结合考古及史料记载，分析和讨论了约1万年以来人地关系的演变历史。 本研究可以得到以下认识： (1)全新世早期(11500～8500 a B. P. )，发育过渡层Lt，夏季风逐渐增强，达到了与冬季风强度相近或略强于冬季风，天水地区气候总体开始转暖变湿。然而，期间的急剧升温事件可能导致严重灾害，不利于生物的繁衍和人类的发展。先民可能仍沿袭着旧的生活习俗和生产方式，以小群落的形式活动于适合采集和狩猎的地方，这一阶段人类与环境的关系尚处于一种自然的状态。 (2)全新世中期(8500～3100 a B. P.)，区内夏季风长期占据优势地位，气候总体上是温暖湿润的。然而这一时期的气候又是不稳定的，期间在总体温湿的大背景下，存在较为频繁的冷暖波动。 8500～6000 a B. P. 是全新世大暖期稳定的暖湿阶段，优越的自然环境为人类古文化的繁盛创造了良好的条件，7800～7300 a B. P. 的大地湾一期文化在这种有利的自然条件下形成并发展。 6000～5000 a B. P. 间的气候恶化事件具有普遍的意义，但是在天水地区，气候的恶化程度相对较小，不足以摧毁人类生存，人类活动仍得以延续。同时，这种环境变化还可以迫使先民去适应和改造环境，发展技术，从而促进人类文明的发展。因而，大地湾村落在这种条件下仍然获得了较为稳定的发展。 5000 a B.P.之后，研究区气候又开始好转，常山文化随之兴起，先民仍过着定居农业生活，使用大量陶器。 (3)全新世晚期(3100aB.P.以来)，研究区内形成了现代黄土并发育了表层土壤。期间冬季风势力再次加强，区内年均气温及降水量都较前期降低，进入了一个相对干旱少雨的时期。寺洼、西周、春秋战国文化中游牧和畜牧经济成份逐渐增加，先民过着居无定所的生活。 (4)研究区全新世期间的年平均气温和年均降水量具有从东南向西北方向逐渐降低的趋势，证明了夏季风场强具有从西北向东南逐渐增强的趋势。因此，自全新世以来，在全球变化和区域气候演变的双重影响下，研究区东南部较西北部明显温湿。 (5)现代天水地区生态环境的恶化，是在过去气候条件恶化的背景下，叠加了人为恶化因素的结果。因此，在目前的生态环境建设当中，科学地协调人地关系，保护天然植被，退耕还林还草，增加植被的覆盖度是遏制水土资源退化的首选途径。更多还原

【Abstract】 Three Holocene loess-palaeosol profiles in Tianshui area were studied by field investigation, intensive sampling and laboratory analysis, including Grain-size (GZ) analysis and measurement of magnetic susceptibility (MS). GZ and MS, used as a proxy indicator of East Asia winter monsoon and a proxy indicator of summer monsoon respectively, together indicate that the climatic environment of Holocene in Tianshui area can be divided into three main stages: first Anathermal, then Magathermal, and last Katathermal, and during the middle Magathermal period, a cold and arid event occurred in the studied area. Meanwhile, based on the climate history, the author also analyzed the evolution of human-earth relationship during the last ca. 10000 years with the help of archaeological studies documents and historical records.The main results in this study are following:(1) Anathermal (11500-8500 a B. P.)Summer monsoon got stronger and stronger, that its intensity closed to or even exceeded what of winter monsoon. As a result, the climate came to get warm and moist in Tianshui area. However, the sharply climatic incidents during this period could cause serious calamity and would be disadvantageous to living beings’ multiplication and human development. Our forefathers still lived a without definite residence life by gathering and hunting. The human-earth relationship was still in an inevitable state at this stage.(2) Magathermal (8500-3100 a B. P.)Summer monsoon occupied the dominant position for a long time, and the weather was warm and moist in our studied area as a whole, nevertheless the climate was not always stable.8500-6000 a B. P., summer monsoon reached its maximum and the climatereached its optimum phase of Magathermal. With this kind of advantageous natural environment, Dadiwan culture came into being and developed rapidly.6000-5000 a B. P., a climatic deterioration incident had taken place in lots of areas besides Tianshui area. But then the deterioration was not so severe in Tianshui area that human activity was still going on. On the other hand, change of environment could compel human beings to adapt to and remodel the environment, to develop technology, consequently to promote the development of human civilization, such as Dadiwan culture.5000-3100 a B. P., it got warmer and wetter again. Changshan culture developed. Our forefathers still lived settling-down life and made use of lots of potteries.(3) Katathermal (Since 3100 a B. P. )At this stage, winter monsoon got strong and climatic deterioration occurred again. Tianshui area entered into a relatively dry and rain shortage period. Nomadic industry and stockbreeding increased in Shiwa and Western Zhou cultures.(4) Average annual temperature and precipitation take on a trend of decreasing gradually from southeast to northwest, which proves the fact that summer monsoon has the trend of increasing from northwest to southeast. Accordingly, under the double influence of global change and regional climate, the southeastern part was obvious warmer and moister than the northwestern part in the studied area in Holocene.(5) The modern ecological environment deterioration of Tianshui area is the result of double actions of climatic deterioration and artificial factors in the past. Thus, in the present construction of eco-environment, it is the first-selected way that we human beings work all out to coordinate the human-earth relationship scientifically, protect the natural vegetation, concede the land to forestry and grass and increase the area covered with vegetations to contain degradations of water and soil resources.更多还原