大兴安岭根河地区晚更新世晚期以来生态环境变迁

据大兴安岭根河镇剖面的孢粉分析、＾１４Ｃ测年并结合沉积地层岩性等资料，揭示该地区晚更新世晚期以来２．５万年期间，生态环境经历了七次变迁。在晚更新世晚期距今２．５￣１．３万年期间有三次亚期演变；在早全新世的１．３￣０．９万年间经过早、晚二次变迁；中全新世的０．９￣０．４年间经过早、晚二次变迁；晚全新世的０．４万年至今。气候的寒温干湿周期０．４万年左右，０．２万年左右发生次一级变化，生态环境随之变迁。     

关中东部全新世黄土——古土壤序列微量元素分布特征及意义

X-荧光光谱仪、磁化率仪和激光粒度仪对尧禾村(YHC)全新世黄土-古土壤序列的微量元素、磁化率、粘粒(<5μm)含量进行了测量。将磁化率曲线、粘粒曲线、Rb/Sr变化曲线和Ba/Sr变化曲线进行了对比分析发现:YHC剖面的磁化率曲线、粘粒曲线、Rb/Sr曲线和Ba/Sr曲线具有高度的同步同向变化趋势,可很好的指示研究区域内全新世的气候变化。而元素的含量变化是该区域气候变化的结果,其中Pb元素在黄土中的含量明显高于古土壤层,属于淋失性元素。Mn、Cr、Cu、Zn、Co、Ti元素在古土壤含量高于黄土层,属于富集性元素。     

Origin and history of grasslands in Central Europe – a review

In terms of origin, grasslands in Central Europe can be classified into (i) natural grasslands, predetermined by environmental conditions and wild herbivores; (ii) seminatural grasslands, associated with long‐term human activity from the beginning of agriculture during the Mesolithic–Neolithic transition; and (iii) improved (intensive) grasslands, a product of modern agriculture based on sown and highly productive forage grasses and legumes. This review discusses the origin, history and development of grasslands in Central Europe from the Holocene (9500 BC) to recent times, using archaeobotanical (pollen and macroremains), archaeozoological (molluscs, dung beetles, animal bones) and archaeological evidence, together with written and iconographic resources and recent analogies. An indicator of grasslands is the ratio of non‐arboreal/arboreal pollen and the presence of pollen of species such as Plantago lanceolata and Urtica dioica in sediments. Pastures can be indicated by Juniperus communis pollen and charcoal present in sediments and the soil profile. Insect‐pollinated species can be studied using cesspit sediments and pollen (from honey) in vessels in graves. In Central Europe, natural steppe, alluvial grasslands and alpine grasslands occurred before the start of agriculture in the early Neolithic (5500 BC); their area was small, and grassland patches were fragmentary in the forested landscape. Substantial enlargement of grasslands cannot be expected to have occurred before the late Bronze Age. The first scythes come from the 7th–6th century BC; therefore, hay meadows probably did not develop before this time. There is evidence of hay meadows in Central Europe during the Middle Ages, documented by macroremains of Arrhenatherum elatius in sediments, written records and long scythes in archaeological assemblages. Based on macroremains analyses, we conclude that there was generally high diversity of seminatural grasslands in the cultural landscape in the Middle Ages, and individual grassland communities were generally species rich. From the beginning of the agriculture until the 18th century, pastures and pasture forests were dominant sources of forage. Large‐scale enlargement of hay meadows and decline of pastures in many regions occurred from the 18th century. Hay making is associated with enlargement of arable fields and the use of cattle as draught animals for ploughing and soil preparation. The spread of A. elatius in Central Europe was enabled by the decline of grazing management and an increased proportion of hay meadows in the 18th and 19th centuries. In some mountain areas, there are no records of large‐scale deforestation and enlargement of grasslands until the 14th century, and the peak of the agriculturally used area was recorded for the period from the 18th to the first half of the 20th century. Grasslands were converted into arable land during periods of war; conversely, grasslands replaced arable land after the collapse of agriculture in many regions of former communist countries following political regime change in the 1990s. The dynamics of the grassland area reflect the development of human society and the political situation, because grasslands are an integral part of the cultural landscape in Central Europe.     

气候条件限制下的人类活动——全新世早中期中国栽培水稻分布的变化对气候变迁的响应

水稻栽培是新石器时代重要的人类活动之一,其发展同气候之间的联系是研究稻作起源和文明发展的一个关键问题。该文利用搜集到的全新世早中期(12 000～5 500 aBP)中国的栽培水稻出土遗址点数据,对全新世早中期中国水稻栽培同气候的关系进行了分析。结果表明,栽培水稻的起源与初期发展具有"边缘效应",即分布于野生稻分布的边缘地带;而其早期的发展和分布也具有类似的特征,即主要受气候因素的影响,因此全新世早中期栽培水稻的分布范围的变化受到气候条件的限制,该时期环境变化受气候"主导"。     

过去3000年季风降水变化与突变事件的洞穴石笋记录对比

基于辽宁省暖和洞2支石笋6个230Th年龄与190个δ18O数据,建立了晚全新世3500～200a B.P.东亚季风降水序列。3个百年尺度的弱季风事件已被证实:2800-2600、1500-1200和400-200a B.P.,其与北大西洋冰漂碎屑事件在发生时间上具有较好的一致性。与内陆高精度、高分辨率石笋δ18O记录对比结果显示:1)轨道-千年尺度季风降水长期趋势变化相一致;2)百年-数十年尺度上季风降水具有明显的区域性,如距今1200-500 a B.P.,东北地区降水逐渐增加,西部干旱-半干旱地区降水逐渐减少,长江中下游以及南方地区降水变化趋势不明显。太阳活动与北大西洋气候波动可能对百年尺度东亚夏季风的强弱变化施加了重要影响。     

河西走廊全新世气候变迁与古文化响应

通过对河西走廊中部黄土剖面磁化率、CaCO3百分含量、色度(明度、红度、黄度)、粒度等气候代用指标的分析,初步重建了河西走廊中部全新世气候变化.发现河西走廊全新世大暖期从9 000 a BP开始,结束于2 200 aBP,期间有3次明显的气候旋回:8000～6200 aBP,5 600～4 300 aBP,3 000～2200 aBP.在此基础上,简单阐述了在中国黄土高原西部,全新世古文化对气候变化的响应,旨在说明河西走廊中部黄土剖面记录的全新世气候变化具有普遍性.     

关中盆地东部李湾剖面全新世高分辨率气候研究

根据李湾剖面磁化率、粒度、微量元素Rb/Sr比值和全铁值的分析结果 ,探讨了李湾剖面黄土纪录所揭示的全新世以来的高分辨率的气候变化。结果发现 :全新世气候的不稳定性在关中盆地东部地区亦有明显的反映 ,这说明 60 0 0 - 50 0 0aB .P .的干旱事件在关中盆地具有普遍性 ;同时 ,本区自 850 0aB .P .以来的全新世最适宜期至少发生了五次气候恶化 ,分别位于李湾剖面深 1 85cm、1 70cm、1 2 5cm、1 0 5cm、85cm附近。     

西安临潼白庙剖面全新世黄土与环境变化

西安临潼白庙剖面全新世发育了两层黄土与两层古土壤 ,通过对该剖面各层黄土与古土壤中微量元素Zn ,Ni,Cr,Co ,Ba ,Rb ,Sr的含量测定 ,研究了当时土壤发育的强弱和气候环境的变化。结果表明 ,其微量元素具有指示冬夏季风等环境变化的重要作用 ,反映了全新世以来该区发生过 4次较大的生物、气候环境的变化 ;古土壤代表的温湿期气候比现今明显 ,当时夏季风活动加强 ,但冬夏季风活动强度与持续时间相近 ,并非是夏季风占优势 ,黄土发育时的气候与现今西安地区类似     

运城盆地全新世时期的野火活动与生态环境演变

通过对运城盆地DXF-S和DXF-N两个全新世典型黄土-土壤剖面磁化率和炭屑浓度的分析,结合已有的研究成果,探讨了该区域野火活动和生态环境演变的基本规律。马兰黄土堆积时期,气候干旱而不稳定,植被呈现荒漠草原或半荒漠草原景观,地方性和区域性野火频繁发生;全新世早期,气候开始由冷干向温湿过渡,但仍比较干旱,野火活动仍然较为频繁,地表植被应为干草原或含有森林成分的干草原景观;全新世中期是全新世最为温暖湿润的时期,野火活动微弱,植被为温带落叶阔叶林为主的森林草原并掺杂少量亚热带植物,但在夏商文化时期,由于人为焚林、围猎、取暖、刀耕火种等生产和生活活动,使野火活动的频率提高,标志着人类开始影响生态环境演变的进程;全新世晚期,气候向干旱化发展,人类生产和生活活动范围的不断扩大,人为野火活动频繁发生,使地表的自然景观逐渐向半自然半人工景观过渡,尤其,近百年以来随着人口的大量增加,聚落规模的迅速扩大,地表已转变为农田景观。     

中国全新世暖期农业考古文化分区及人地关系特征

论文首先讨论中国全新世时期农业考古文化区划的研究进展,并提出了我国全新世暖期的农业考古文化总体可以分出四个文化区:1)北方粟黍旱作农业文化区;2)旱作北界以北以西的渔猎采集或游牧文化区;3)南方稻作文化区;4)东南沿海的渔猎文化区。最后从人地关系的角度讨论了全新世暖期的农业考古文化与环境的关系。