萨拉乌苏河流域萨拉乌苏组砂丘砂沉积特征

The Salawusu Formation of Milanggouwan section in Salawusu River Valley includes 7 layers of paleo-mobile dune sands, and 4 layers of paleo-fixed and semi-fixed dune sands. Their structures have been observed and their grain size, surface textural features and several main chemical elements have been analyzed. The results showed that： 1） Some of the aeolian structural characteristics of these dune sands are similar to that of the recent dune sands. 2） They are also similar to the recent dune sands in grain size components, and parameters of Mz,σ, Sk and Kg, as well as in several main chemical components. 3） The scattergrams of Mz-σ and SiO2-Al2O3＋TOFE and the probability curves of grain size showed that these paleo-dune sands are different from paleosols and fluvio-lacustrine facies, but are consistency with recent dune sands. 4） Quartz sands have well roundness and surface textural features such as dish-shaped pits, crescent-shaped pits, pockmarked pits, upturned cleavage plates, siliceous precipitates and siliceous crevasses, indicating that they had been carried for a long time by the wind. As the 11 layers of paleo-dune sands possess the aeolian characteristics in structure, grain size, surface textural features and chemical elements, the origin of their formation should be attributed to eolation.     

Sedimentary characteristics of paleo-aeolian dune sands of Salawusu Formation in the Salawusu River Valley

The Salawusu Formation of Milanggouwan section in Salawusu River Valley in-cludes 7 layers of paleo-mobile dune sands, and 4 layers of paleo-fixed and semi-fixed dune sands. Their structures have been observed and their grain size, surface textural features and several main chemical elements have been analyzed. The results showed that: 1) Some of the aeolian structural characteristics of these dune sands are similar to that of the recent dune sands. 2) They are also similar to the recent dune sands in grain size components, and parameters of Mz, σ, Sk and Kg, as well as in several main chemical components. 3) The scattergrams of Mz-σ and SiO2–Al2O3+TOFE and the probability curves of grain size showed that these paleo-dune sands are different from paleosols and fluvio-lacustrine facies, but are consistency with recent dune sands. 4) Quartz sands have well roundness and surface textural features such as dish-shaped pits, crescent-shaped pits, pockmarked pits, upturned cleavage plates, siliceous precipitates and siliceous crevasses, indicating that they had been carried for a long time by the wind. As the 11 layers of paleo-dune sands possess the aeolian characteristics in structure, grain size, surface textural features and chemical elements, the origin of their formation should be attributed to eolation.     

青藏高原东北部共和盆地风成沉积地球化学特征及其揭示的气候变化

通过对共和盆地东部风成沉积的地球化学分析,并结合14C和OSL年代,重建了区域末次盛冰期以来气候变化过程。21 ka BP之前气候寒冷偏湿,21～15.82 ka BP为末次盛冰期(LastGlacial Maximum,LGM),气候极为寒冷干燥;15.82～9.5 ka BP气候转暖且偏干,其中14.5～13.6ka BP和11.9～9.5 ka BP气候明显冷干,分别为老仙女木时期(Oldest Dryas,OD)和新仙女木时期(Younger Dryas,YD),而15.82～14.5 ka BP和13.6～11.9 ka BP(BФlling-AllerФd暖期,B/A)相对温暖;9.5～7.2 ka BP暖湿程度明显提高,7.2～5.1 ka BP气候波动频繁,相对冷干和相对暖湿多次更替。5.1～2.7 ka BP暖湿程度基本稳定,之后气候趋于寒冷但湿度明显较大。这些气候变化过程与青藏高原大量的古气候信息记录具有良好的一致性,表明共和盆地气候变化与青藏高原气候变化的高度一致性。     

西北半干旱雨养农业区薯麦轮作FACE平台简介

在黄土高原半干旱雨养农业区薯麦轮作田地建立气象部门首家FACE系统(Free Air CO<,2>En-richment),即CO<,2>浓度的控制和监测系统平台,由中国气象局兰州干旱气象研究所建在定西半干旱生态环境与试验基地.该平台由CO<,2>气体供应装置、控制系统、释放系统3大部分组成,它是利用计算机网络系统对平...     

THE CAUSES AND DEVELOPMENTAL TREND OF DESERTIFICATION IN THE MIDDLE REACHES OF THE YARLUNG ZANGBO RIVER AND ITS TWO TRIBUTARIES IN XIZANG

ＴＨＥＣＡＵＳＥＳＡＮＤＤＥＶＥＬＯＰＭＥＮＴＡＬＴＲＥＮＤＯＦＤＥＳＥＲＴＩＦＩＣＡＴＩＯＮＩＮＴＨＥＭＩＤＤＬＥＲＥＡＣＨＥＳＯＦＴＨＥＹＡＲＬＵＮＧＺＡＮＧＢＯＲＩＶＥＲＡＮＤＩＴＳＴＷＯＴＲＩＢＵＴＡＲＩＥＳＩＮＸＩＺＡＮＧＤｏｎｇＧｕａｎｇ...     

黄土地层中奇异微颗粒的发现与初步研究

通过蓝田段家坡黄土和红粘土剖面与第四纪3次巨大撞击事件年代相应的地层内奇异微颗粒的研究,将其划分为5种不同的形态类型,并主要据化学成分,将5类奇异微颗粒归纳为撞击、火山和生物等3种成因类型。文中还提出综合成因模式来解释不同奇异微颗粒赋存于同一撞击事件时段的地层及它们所显示的因果联系。     

莒县全力做好土地开发整理工作

莒县国土资源局在上级主管部门的正确领导下，积极落实中央关于“在开发中保护，在保护中开发”的精神，进一步加大对山丘区土地开发整理工作的力度，2001年以来，组织实施国家、省、市、县4级土地整理项目36个，总投资1．0904亿元，整理土地总面积7586．57hm^2，新增耕地958．11hm^2，土地开发整理工作不断跃上新台阶，农业生产条件得到明显改善。     

西北干旱区棉花对气候变化响应的评价指标体系

近年来,在全球变暖的大背景下,西北也经历着同样的变暖趋势,尤其在西北干旱区新疆、甘肃河西走廊等地的棉花种植区,气候变暖对棉花生长发育的影响研究日益增多,但如何正确、合理地评价棉花对气候变暖的响应,已成为目前十分突出的科学和实际问题。在评价的过程中,评价指标的选择和确定是重中之重。鉴于此,本文筛选了几类重要的评价指标,主要有棉花生长发育、产量品质、种植结构、地理分布、农业气象灾害、农业病虫害气象指标等,这些指标的选择为科学评价棉花对气候变化的响应奠定了一定的基础。     

A Multi-cycle Climatic Fluctuation Record of the Last Interglacial Period:Typical Stratigraphic Section in the Salawusu River Valley on the Ordos Plateau,China

The Last Interglacial Period strata in the Milanggouwan section in the Salawusu River valley on the Ordos Plateau, China, have 8.5 sedimentary cycles composed alternately of eolian dune sands, fluvio-lacustrine facies and paleosols. Based on comprehensive analyses on the distribution of magnetic susceptibility and CaCO3 and paleo-ecology indicated by fossils in the region, it is considered that the sedimentation cycles resulted from dry-cold and warm-humid climate fluctuations. Magnetic susceptibility values and CaCO3 contents in stratigraphic sectors Ⅰ, Ⅲ, Ⅴ and Ⅱ, Ⅳ basically respectively present peaks and low vales, and the former three can in time correlate with MIS5a, MIS5c and MIS5e successively and the latter two with MIS5b and MIS5d. In addition, some horizons of eolian dune sands and the low vales of their magnetic susceptibility and CaCO3 are also correlated with 6 periods of cooling events indicated by the higher content of foraminifer Neogloboquadrina pachyderma (S.) documented in the V29-191 drill in the North Atlantic and the cold events recorded by δ^18O in the ice cores in GRIP, especially with 9 periods of dust events in Chinese Loess Plateau.     

Aeolian Facies Belts in the Taklimakan Desert1

At least at the beginning of the last glacial epoch, the facies belts of dune sand, sandy loam and loess formed by winds had existed in the Taklimakan desert and areas south of it. There were no appreciable changes in the NE and NW wind systems and their wind forces that deposited dune sand, sandy loam and loess in the global cold stage since the last glacial epoch; accordingly no marked shifts of the boundaries of these aeolian facies belts took place. In the global warm stage since then, the climate in the Taklimakan desert and areas south of it became warm and dry, resulting in ablation of substantial volumes of ice and snow in their surrounding mountains and thus forming alluvial and diluvial deposits in the region. The alluvial-diluvial actions, however, failed to change the general framework of aeolian facies belts.