玛多—甘德断裂甘德段晚第四纪活动特征

玛多—甘德断裂是巴颜喀拉块体内部的一条活动断裂。 通过野外调查发现, 在玛多-甘德断裂的甘德段保留有一条较好的地震地表破裂带。 破裂带整体走向NW向, 长约为50 km。 野外获得的最大左旋水平位移7.6 m, 最大垂直位移4 m。 沿破裂带有大量地震活动的遗迹, 地表破裂类型十分丰富。 通过对各种地质地貌现象的调查与分析, 认为该破裂带形成时代较新。 断裂带在地貌上发育有线性排列的垭口、 断层三角面、 断层陡坎、 断层泉、 断错水系、 山脊扭错、 断塞塘、 鼓包等现象。 根据野外考察并结合现有资料分析, 该破裂带可能是该区域内历史上一次较为强烈地震的产物。 据此推断, 巴颜喀拉块体内部的玛多—甘德断裂晚第四纪以来可能有过强烈的活动并至今活跃。     

Ecological response to the climate change on the northern slope of the Tianshan Mountains in Xinjiang

The relationship between the terrestrial ecosys-tems and the climate change is one of the importantfields in the study on global change,and the rela-tionship between vegetation and climate change is oneof the main research focuses[1―3].On the one hand,the high-amplitude global warming results in the increase of evaporation from the oceans and the waters on land and of precipitation in most parts of the oceans and theterrestrial regions,thus,the modern glaciers are seri-ously melted,the runoff …     

CALCULATIONS OF WAVE BREAKING PROBABILITY AND DISTRIBUTION OF BREAKING WAVE HEIGHTS IN DEEP WATER

lareODUcrI0NThephenomenonofbreakingwavesintheoasnoocurswheneveramomentahiyhighcrestmecheSanunstablecondition.It0ccursintendtimhy,andtheoccurrencefre-qUencydePendsonthescastate.ManystudAshaddricaniedoutontheoccurmcefre-qUencyofbrmkingwavesindeepweter.0chiandTsai(l983),LongueHiggins(l975)andVanD0mandPamn(l975)nadstheptalictonofbrmkingwavesoccurrenceindeePwater,usingabaskingcriterionforindividualwavesbasedonthewavesmpness.ThecriterioncanbeexpmeedintennSofthewaVehdghtHandperiodTasH>PgT'(…     

溶菌酶与硅灰石类粉尘中活性物质的反应行为研究（Ⅰ）——样品中活性SiO3^2-与溶菌酶的作用机理

对 3个不同地区的硅灰石类粉尘做了XRF分析及其与溶菌酶 (Lys)的反应实验 ,结果显示Lys与样品中的活性物质进行了反应。模拟样品中元素离子与Lys反应的UV_Vis和荧光光谱分析表明 ,37℃下Lys与样品中的元素离子SiO2 -3 作用最明显 ,表现在紫外区吸收峰红移 10nm ,吸光度增大 ,荧光区λem4 4 0nm处荧光强度增强 ,荧光峰红移 2 0nm。同时 ,对其反应机理和结合位点进行了探讨     

Obduction-type granites within the NE Jiangxi Ophiolite: Implications for the final amalgamation between the Yangtze and Cathaysia Blocks

Leucogranitic lenses are found within the Xiwan ophiolitic mélange in northeastern Jiangxi Province, South China. The leucogranites occur exclusively within the serpentinized peridotite unit of the ophiolite suite. SHRIMP U–Pb zircon dating results indicate that these granites were formed at 880 ± 19 Ma, and were overprinted by an Indosinian tectono-thermal event at ~ 230 Ma. The leucogranites are peraluminous (A/CNK = 1.0–1.24), characterized by high Al₂O₃ (14–18.33%) and Na₂O (6.5–10%) and clearly low εNd(T) values of 0.8 to − 3.9 compared with the other rock units of the ophiolite suite. On the basis of their REE characters, the leucogranites can be divided into three groups. Group I leucogranites show the most fractionated LREE-enrichment patterns (with La_N/Yb_N and La_N/Sm_N ratios of 30.1–75.0 and 2.3–3.9, respectively). Group II leucogranites have moderately fractionated LREE-enrichment patterns (with La_N/Yb_N and La_N/Sm_N ratios of 13.1–26.5 and 0.8–1.9, respectively). Group III leucogranites are characterized by obviously low total REE contents and flat REE patterns with significant positive Eu anomalies, probably due to small degrees of partial melting. All these leucogranites were likely formed by partial melting of sedimentary rocks from a marginal basin at the Yangtze side of the orogen, beneath a major thrust fault during the obduction of the ophiolite onto the continental crust. They are broadly similar to obduction-related granites within ophiolites identified in many places worldwide. Identification of the ca. 880 Ma obduction-type granites in the NE Jiangxi ophiolite provides a petrological constraint on the timing of the ophiolite obduction onto the continental crust. In combination with the termination of the Shuangxiwu arc magmatism at ca. 890 Ma, we interpret that the close of the Neoproterozoic back-arc basin and the termination of the continental amalgamation between the Yangtze and Cathaysia Blocks occurred at ca. 880 Ma.     

浅谈核废物地质处置

本文介绍美国、加拿大、西德等国的核废物地质处置状况。探讨核废物地质处置的意义、目的、任务、方法、技术和前景。提出在我国利用断裂构造频率法选择相对稳定地区的可能性。     

The geochemistry and petrogenesis of the lavas of the Vulsinian District,Roman province,Central Italy

The Vulsinian lavas are dominated by a suite of undersaturated leucite-bearing basic to intermediate compositions. The remaining lavas are mainly oversaturated and have shoshonitic affinities. One hundred and thirty-five samples have been analysed for major elements and most for 20 trace elements. Twenty-seven lavas have been analysed for REE. They are all perpotassic (for the undersaturated lavas: K₂O/Na₂O=2–8) and have very high LIL element concentrations, (e.g. Rb=400–800 ppm, Th=25–150 ppm, REE/REE_cho=c.200, (LREE/HREE)_cho=c.20) even in the most basic rocks.The undersaturated lavas appear to be interrelated by fractional crystallization of cpx±olivine (from 14 to 11 wt.% CaO), cpx+leu±plg±mica (from 11 to 8 wt.% CaO), cpx+leu+plg+apa+magnetite±mica (from 8 to 5 wt.% CaO), and additional sanidine (or hyalophane)±haüyne (from 5 to 3 wt.% CaO). The saturated lavas and the few slightly undersaturated shoshonite basalts are thought to be evolved from the undersaturated magma(s) by crustal contamination or mixing with silica-rich magmas. The parental Vulsinian magma having: Mg-value=c.73, Cr=300–700 ppm, Ni=100–125 ppm, Sc= 40–50 ppm, Fo_89–92, Di_77–97 approximates a primary, mantle-derived liquid. Enrichment in LIL elements (incl. REE) and LREE/HREE suggest a small degree of partial melting from fertile mantle; whereas the low concentrations of Na, Ti and P suggest larger degrees of partial melting. This indicates that either the primary magma or the parental mantle was metasomatized by a fluid, which previously equilibrated with subducted continental material. This model agrees with published high ¹⁸O, high ⁸⁷Sr/⁸⁶Sr and low ¹⁴³Nd/¹⁴⁴Nd.     

Carbon sequestration effects of shrublands in Three-North Shelterbelt Forest region,China

Three-North Shelterbelt Forest(TSF) program, is one of six key forestry programs and has a 73-year construction period, from 1978 to 2050. Quantitative analysis of the carbon sequestration of shrubs in this region is important for understanding the overall function of carbon sequestration of the forest and other terrestrial ecosystems in China. This study investigated the distribution area of shrubland in the TSF region based on remote sensing images in 1978 and 2008, and calculated the carbon density of shrubland in combination with the field investigation and previous data from published papers. The carbon sequestration quantity and rate from 1978 to 2008 was analyzed for four sub-regions and different types of shrubs in the TSF region. The results revealed that: 1) The area of shrubland in the study area and its four sub-regions increased during the past thirty years. The area of shrubland for the whole region in 2008 was 1.2 × 10~7 ha, 72.8% larger than that in 1978. The Inner Mongolia-Xinjiang Sub-region was the largest shrubland distribution area, while the highest coverage rate was found in the North China Sub-region. 2) In decreasing order of their carbon sequestration, the four types of shrubs considered in this study were Hippophae rhamnoides, Caragana spp., Haloxylon ammodendron and Vitex negundo var. heterophylla. The carbon sequestration of H. rhamnoides, with a maximum mean carbon density of 16.5 Mg C/ha, was significantly higher than that of the other three species. 3) The total carbon sequestration of shrubland in the study region was 4.5×10~7 Mg C with a mean annual carbon sequestration of 1.5 ×10~6 Mg C. The carbon density in the four sub-regions decreased in the following order: the Loess Plateau Sub-region, the North China Sub-region, the Northeast China Sub-region and the Inner Mongolia-Xinjiang Sub-region. The paucity of studies and data availability on the large-scale carbon sequestration of shrub species suggests this study provides a baseline reference for future research in this area.