乌鲁木齐河流域不同水体中的氧稳定同位素

采用乌鲁木齐河流域历年采集的降水、表层粒雪、冰川融水和河川径流等水样资料,分析了取样期间不同水样中氧稳定同位素的变化,揭示了降水中氧稳定同位素变化存在着明显的温度效应,而温度效应又与海拔高度有关;表层粒雪和冰川融水中氧稳定同位素则无明显的高度效应;冰川融水中的氧稳定同位素比率小于河川径流中的氧稳定同位素比率。评估了不同影响因子对水循环过程中稳定同位素变化的影响及相互作用,为稳定同位素技术在水循环研究中的应用提供了实例。     

延边地区浅成低温热液-斑岩型金矿成矿系列的氢、氧同位素特征

延边地区浅成低温热液-斑岩型金成矿系列的氢、氧同位素研究表明,δ(18O)=-10×10-3～+5×10-3,δ(D)=-120×10-3～-40×10-3。小西南岔金(铜)矿床早期成矿流体主要以岩浆水为主,成矿晚期有少量大气降水的加入,为典型的斑岩型金铜矿床;刺猬沟、五凤金矿床成矿流体主要以大气降水为主,水岩作用比值W/R=0.2～2,为浅成低温热液型矿床;闹枝金矿床的成矿流体是介于上述两种类型之间的过渡型。     

峨眉地幔柱-岩石圈的相互作用:来自低钛和高钛玄武岩的Sr-Nd和O同位素证据

蛾眉山玄武岩总体具有较高的^87Sr／^86Sr比值和较低的εNd(t)值，并具有富集地幔源区的特点。而低钛玄武岩(LT)与高钛玄武岩(HT)间又表现出一定的差异性，即早期低钛玄武岩(LTl)的^87Sr/^86Sr比值最高(0．7063—0．7078)，而其εNd(t)最低(—6．74-—0．34)：晚期高钛玄武岩(HT)具有最低的^87Sr/^86Sr比值(0．7049—0．7064)和最高的εNd(t)值(—0．71—1．5)。蛾眉山低钛玄武岩中单斜辉石的氧同位素变化范围为6．2‰-7．86‰，高于洋岛拉斑玄武岩的平均值5．4‰。研究样品较地幔岩石偏高的δ^18O值说明在其形成和演化过程中有壳源物质的参与。结合前人的研究成果和对元素地球化学的研究认为，壳源物质可能主要来自于新元古代富集的扬子西缘次大陆岩石圈地幔。地幔柱—岩石圈的相互作用过程中表现在时间和空间的系统变化，即早期西岩区形成含大量壳源组分的低钛玄武岩，晚期为壳源组分相对较少的高钛玄武岩。空间上低钛玄武岩仅分布在西岩区，而中、东岩区皆为高钛玄武岩。壳源组分随着时间演化逐渐减少，在空间上由西而东也逐渐减少。表明蛾眉山火成岩省形成早(主)期地幔柱头卷入并熔融了较多交代富集的次大陆岩石圈物质，晚期则有较少的壳源物质参与。建立了蛾眉地幔柱与大陆岩石圈作用的工作模型。     

Oxygen isotope compositions of quartz grains (4—16μm) from Chinese eolian deposits and their implications for provenance

In recent years, the researches of inland Asia aridification since late Cenozoic have attracted much attention in the paleoclimate community. Rea et al.[1] studied a 12 Ma eolian record in North Pacific and associated it with the aridification of northwes…     

不同粒级黄土-古土壤中碳酸盐碳氧稳定同位素组成及其古环境意义

从黄土高原中部洛川和环县两个剖面选取若干黄土和古土壤样品，分为三种粒级（＞45μm、2－45μm、＜2μm），挑出＞45μm粒级中的根状结核与蜗牛壳化石碎片，分别测定δ^13C和δ^18O值。结果显示，两个剖面不同粒级组分的δ^13C和δ^18O值表现出相似的分布规律。洛川剖面的根状结核和蜗牛壳与分粒级样品中的＜2μm粒级中碳酸盐的δ^13C和δ^18O值最为接近，处于相同的区域内；而＞45μm粒级中的δ^13C和δ^18O值与其他样品有明显的差别。因此，可以认为黄土－古土壤中＜2μm粒级中所含的碳酸盐可代表成镶碳酸盐，其蕴涵的地球化学信息可用以重建成壤时的古气候和古环境条件。     

长江中游和尚洞石笋的高分辨率同位素、微量元素记录及古气候研究

通过对长江中游和尚洞HS-2号石笋的沉积特征及C、O同位素Mg、Sr微量元素相结合分析,利用U系法定年,获取了长江中游19.0ka～6.9ka的古气候、古环境信息(平均分辨率为17a,局部分辨率达到7a).得出如下结论(1)19.0～16.6ka, C、O同位素偏轻,气候冷湿;(2)16.6～11.1ka, C、O同位素偏重, 气温上升,降水偏少;(3)11.1～10.3ka 干热时期中的突然回冷事件对应于新仙女木事件(Younger Dryas Event);(4)10.3～6.9 ka B.P δ18O及δ13C值逐渐变轻,而Mg/Sr比继续增大,表现为气温上升,降雨量较大.反映了历史时期湿冷、干热、湿暖交替变化的气候趋势,得出了长江中游千年级和百年级的一些气候变化趋势,特别是发现了新仙女木事件在长江中游洞穴石笋中完整的记录,说明新仙女木事件是全球性气候突变与环境灾变事件     

The free jet as a means to improve water quality: Destratification and oxygen enrichment

Rivers, lakes, and coastal waters are chaotic systems — physical, chemical, and biological parameters influence their development. Each parameter itself is influenced by the system. Human interaction has led to fast eutrophication. Oxygen input and artificial mixing have been considered as tools to overcome the biggest problems of fish kills, algal blooms, and bad odour. The favoured technology for destratification and oxygen input so far is the bubble curtain. This technology has been applied successfully in several cases. But often, this technology could not be implemented because of high investment and operating costs.

Alternatively, the free jet is discussed as an efficient and low investment and operating cost technology. The free jet may transport oxygen-rich water from the surface down into the hypolimnion, thereby destratifying a water system. A free jet entrains on its way down even more oxygen rich and warm epilimnic water. This water will finally — if some mixing with the cold hypolimnic water occurs — be transferred to the metalimnion. The density differences will make this water travel long distances.

The energy input may be very low and the objective must not be to totally overturn a system. A jet started in early spring may help a lake to have a deep enough epilimnion, relatively large in volume in respect to the hypolimnion, and the normal wind will recirculate the water transferring enough oxygen to the deeper part, thus expanding the fish habitat and enabling benthic fauna. Literature also shows that the occurrence of massive algal blooms may be reduced.

The oxygen efficiency can be multifold compared to standard technologies.     

海南岛沙老岸礁区滨珊瑚氧、碳同位素对气候的记录

通过对海南岛沙老岸礁中正在连续生长的澄黄滨珊瑚骨骼进行氧，碳同位素的测定，对9年生长的珊瑚骨骼依次分析了352个样品，平均每旬有1－2个控制样品，以此来分析珊瑚生长期间的气候变化。首先分析出每年雨季和旱季的差别，得到雨季和旱季曲线的特征，并得出雨季在每年夏季，旱季在每年的秋冬季，表明海南岛礁区是典型的季风气候区。同时将珊瑚骨骼的氧同位素分析数值与相关记录的气温资料做比较，它们的相关系数为0．97和0．79，并得出以氧同位素分析数值求气温的公式。     

Changes in the Thermal Climate in Northwestern Europe during Marine Oxygen Isotope Stage 3, Estimated from Fossil Insect assemblages

More than 30 fossil coleopteran (beetle) assemblages have been recorded from oxygen isotope stage 3 in northern Europe, comprising several hundred identified species. Using the mutual climatic range method for quantifying palaeotemperatures, these assemblages show that the climates of the times can be divided into two distinct interstadial types. One, a short phase of temperate/oceanic climate occurred between 43,000 and 42,000 ¹⁴C yr B.P. when conditions were not much different from those of the present day. In spite of the temperate climate, trees did not colonize northwestern Europe at this time. Two, both before and after this temperate interlude there were phases of cold/continental climate during which summers were too cold for trees to grow and winters were of Siberian intensity. It is possible that periods of even colder conditions intervened from time to time between the interstadial but, because of the intensity of the cold, biological systems were so inhibited that no fossil evidence for them can be found in northern Europe. Evidence for them must be sought in the fossil records from the warmer parts of southern Europe or in the physical evidence in the Greenland ice cores.