伊犁河谷文化遗址时空分布及地理背景研究

选取伊犁河谷为研究区,探讨了夏朝以来的1 029处遗址时空分布和地理背景。结果表明：遗址分布的地貌类型依次为“河岸阶地→河流谷地、谷地的丘陵和高阶地→低起伏低山和低丘陵→冲（洪）积平原、河谷平原”。遗址分布范围分别经历了“分散”、“扩大”、“收敛”、“集中”的演变,其空间格局由前3个时期的“东高西低”演变为后3个时期的“西高东低”,其分布中心经历了从河流“中上游→下游”的演变。遗址集中分布于第2～8级（601～1 300 m）高程和第1～5级坡度（0～9°）,且随着时间的推移,其表现出从高海拔、高坡度向低海拔、低坡度转移的趋势。古遗址数量、规模均以宋元明时期最高,而古墓葬则以春秋-秦时期居首。古墓葬遗址主导文化经历了“安德罗诺沃文化→索墩布拉克文化→乌孙文化”的演变过程。     

长江中下游成矿带磁异常揭示的深部构造与成矿关系

长江中下游成矿带是我国最主要的铁铜金多金属成矿带之一。本文通过高精度航磁异常数据分析成矿带内磁异常的分布特征,研究表明,火山岩盆地和郯庐断裂带沿线的正磁异常呈团块状分布,而大别造山带和九华山的正磁异常呈宽缓分布,前者与成矿带内以铁矿化为主的多金属矿床密切相关。航磁异常边界识别结果清晰揭示了郯庐断裂带、晓天-磨子潭断裂和襄樊-广济断裂等区内重要的深大断裂,九江附近的边界可能是郯庐断裂带的南延。长江中下游及邻域的居里等温面深度变化范围约为23.5~31.5km,沉积盆地下方居里等温面总体呈现拗陷,火山岩盆地下方居里等温面总体呈现隆起,郯庐断裂带沿线的居里等温面呈带状分布的隆起。大别造山带和九华山下方居里等温面呈现拗陷,有别于火山岩盆地和郯庐断裂带沿线的居里等温面隆起。长江中下游成矿带内主要的铁铜多金属矿床点集中分布在居里等温面隆起或隆起边缘部位,指示了长江中下游早白垩世剧烈的岩浆活动使区域大地热流值相对较高,地壳深部的构造格局和岩浆活动制约了浅部的成矿。     

The Widdington Sands: High-level Kesgrave Sands and Gravels near the Cam-Stort interfluve,Northwest Essex,UK

A small but stratigraphically significant exposure of Quaternary sandy sediments (Widdington Sands) was observed and recorded in the early 1970s in northwest Essex. These data are here re-examined and re-evaluated, yielding new insights into early proto-Thames aggradation following the marine recession of the Norwich Crag Formation (MIS 74–71, about 2 Ma). As the proto-Thames trajectory shifted south eastwards, a period of landscape stability ensued in the early Middle Pleistocene (MIS 19–13) during which the Valley Farm Soil was formed. This and the succeeding Barham Soil can be recognised in the stratigraphy, the second palaeosol heralding the arrival of glaciation in the Anglian Stage (MIS 12, 480–420 ka). These pedogenic signatures are enclosed within palaeokarstic features in the form of infilled sinkhole pipes. A large doline has functioned as a sediment trap preserving pre-truncation structures including reverse ring faults. These confirm basal support removal leading to upward migration of a dissolution cavity and roof collapse within the sinkhole pipe. The process and timing of subsidence can thus be defined more clearly than for similar features found in comparable Kesgrave aggradations of the Middle Thames. The likely glacitectonic origin of the planar sub-till surface is examined and discussed. Dating of Early Pleistocene fluvial activity is constrained by estimating the height of a former terrace surface whose elevation points to a correlation with the higher Stoke Row Member (MIS 64, 1.8 Ma), suggesting the oldest known proto-Thames activity within southern East Anglia.     

新疆天山西部巩乃斯河谷积雪与森林/草地 覆盖条件下季节冻土特征分析

不同的覆盖条件下,季节冻土的特征会存在差异。为了分析积雪与森林/草地覆盖条件下季节冻土的特征,在新疆天山西部巩乃斯河上游的中国科学院天山积雪雪崩研究站的实验场地监测了森林-积雪,草地-积雪,以及草地覆盖条件下季节冻土的冻结深度,并对有无积雪覆盖条件下季节冻土发育过程中的土壤温度和土壤含水量进行了跟踪测量。结果表明：森林-积雪覆盖条件下季节冻土的冻结深度最浅,草地-积雪覆盖条件下次之,草地覆盖条件下最深。积雪的存在可以改变季节冻土的冻结深度,还会影响土壤温度和土壤含水量变化。在季节冻土的发育阶段,积雪的隔热作用使得有积雪覆盖条件下土壤温度和土壤含水量较高;在积雪消融阶段,由于积雪融水的补给,土壤含水量也相应地增加,积雪消失后由于蒸发的存在导致土壤含水量减少。     

叶城波龙7.20泥石流应急调查及灾害链实时观察

针对叶城柯克亚乡波龙7.20突发泥石流灾害,现场开展了应急科学调查。对沟下游泥石流堆积区进行量测,对上游突发小型滑坡-堰塞湖-泄流全过程开展实时观察。结果发现:泥石流固体物质主要是晚更新世风积土滑坡和中元古变质岩及碳酸盐岩崩塌,水体来源主要是强降雨导致的上游洪水及堰塞湖溃决;沟谷上游以稀性泥石流为主,下游加入了崩塌块体及河道砂砾石,粘度有所增大;堆积区呈块石散落和淤积状态。据现场多个老堰塞坝推测,波龙沟泥石流发生周期约15~20年。现有停车场位于沟口堆积区,需加大极端洪水及泥石流排泄空间,拓宽排导沟槽净空。     

下扬子区三叠纪古生物和古地理变迁及其主要原因

根据下扬子区三叠系生物化石和沉积相的研究，该区三叠纪古地理环境先后经历陆表海，萨布哈潮坪－泻湖，下三角洲平原滨海河口湾及三角洲平原河，湖和沼泽一系列变迁，其主要原因是由于扬子板块从赤道以南附近持续向北进行跨气候带漂移抵达北回归线以北附近的结果。     

Heavy metal distribution and environmental status of Doon Valley soils, Outer Himalaya, India

 Doon Valley is surrounded by two major river systems (Ganga and Yamuna) on either side, with a water divide passing nearly across the centre of the valley, and is sandwiched between two mountain ranges in the fragile ecological systems of the Himalayan foothills. In total 398 soil samples were collected from the valley in a grid pattern (∼1 sample per 2 km²) and investigated for their heavy metal (Cr, Cu, Ni, Pb and Zn) abundances that are environmentally sensitive. Comparison of the heavy metal abundances with the contamination threshold values (CTV) revealed that most of these elemental abundances in Doon Valley soils fall well within the range of the uncontaminated to slightly contaminated category. In the case of Cr and Ni, a sizeable number of samples exceeded the CTV (250 and 100 mg kg^–1 respectively) with an overall background value of 109 and 52 mg kg^–1 respectively. Sites of high Cr and Ni mostly occur in the Ganga Catchment (GC) sector that includes even relatively undisturbed forestland. The source of this contamination is attributed to geological factors which indicate contribution from the mafic volcanics of the Lesser Himalaya. This is also consistent with the distribution pattern of Mn and Fe, though their abundance levels are not alarming. The background concentration of Pb is low (22 mg kg^–1) in Doon Valley soils; however, signs of gradual Pb contamination are palpable in and around the centre of the Dehra Dun city and along the highways. Aluminium normalized heavy metal ratios were found to exhibit narrow variability in the case of Cu, Ni and Cr and had good correlation with Al, indicating their affinity and association with the clay minerals. On the other hand, Pb and Zn seem to be associated with non-silicate sources. Received: 7 January 2000 · Accepted: 30 July 2000     

太行山区河谷内居民点的特征及其分布格局的研究--以河北省阜平县为例

以河北省阜平县的5条河流主流河谷为案例，全面分析了河谷内居民点的斑块特征和分布格局，表明，河谷内的居民点位置基本是在的向阳一侧靠近坡脚的地方，一般以狭长形状为主；居民点面积在河谷面积中所占的比例在各个河段的变化很大，但不同河流居民点面积占河谷面积的比例十分接近，在10%-17%的范围内变支。在研究区内，河段内居民点的面积与河谷面积、河谷内农田面积是呈正相关的，表明本地区河谷内的居民对河谷土地具有很强的依赖性；河谷内的居民点增加使河谷林木急剧减少，但居民点内部和周围的河谷林木为其安全性、舒适性提供了保障。     

21世纪初长江干流地区经济持续发展的战略思考

长期以来长江干流地区始终承担着全国工业化主体发动机的作用。随着国家工业化及城市化进程的加快,21世纪初长江干流地区的这种作用还将得到明显增强。作为全国人地关系最为紧张的地区之一,长江干流地区需从自身特点出发,合理调整地区产业结构和布局方向,以期真正担负起国家和民族发展所赋予的历史使命。