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21.
用现代地层学方法判别冈瓦纳大陆的北界   总被引:12,自引:1,他引:12       下载免费PDF全文
在深入研究1:100万“改则幅”和“日土幅”区调中大量原始资料和青藏高原生物地理区系与地壳演化的基础上,用现代地层学方法,重点研究羌塘地块和唐古拉地块的属性及冈瓦纳大陆的北界。笔者首先排除了推覆构造对建立古大陆边缘造山带原地岩系地层层序的严重干扰,对羌塘地块和唐古拉地块的地层层序进行了重建,提出了羌塘地块古大陆边缘现代地层学格架的演化模式。羌塘地块古大陆边缘有两个不同属性而又相互关联的地层体,现今呈一西一东的分布格局,向洋(古特提斯洋)一侧为以深水砂泥复理石和放射虫硅质岩为主的沉积组合类型,向陆一侧为以浅水碎屑、碳酸盐为主的沉积组合类型。从而证实了古特提斯洋存在一个向羌塘地块古大陆边缘倾斜的俯冲消减带。它导致羌塘地块古大陆边缘活化造山运动,并于中二叠世末期与唐古拉地块碰撞,形成晚海西褶皱带。探讨了不同时期不同地块骨骼同位素的演变特征及其成因解释。论述了羌塘地块生物地理区系的发生、发展、消亡与羌塘地块同冈瓦纳大陆分裂、向北漂移(导致新特提斯洋形成)及同唐古拉地块碰撞(导致古特提斯洋消亡)的板块活动关系。  相似文献   
22.
Forests play an important role in regulation of the global climate; moreover, they provide human beings with a whole range of ecosystem services. Forest health and ecosystem functioning have been influenced by anthropogenic activities and their consequences, such as air pollution, surface mining, heavy metal contamination, and other biotic and abiotic stress factors, which had an especially serious effect on central Europe. Many aspects of the physiological state of trees are more or less related to the concentrations of two main groups of leaf photosynthetic pigments: chlorophylls and carotenoids. Therefore, their contents can be used as non-specific indicators of the actual tree physiological status, stress and the pre-visible tree damage. Variations in leaf biochemical composition affect foliar optical properties and can be assessed remotely using high spectral resolution data (hyperspectral data). These data were successfully used in earlier studies to detect vegetation stress and damage. However, only a few approaches have dealt with the use of hyperspectral remote sensing to assess vegetation physiological status on a regional scale. Moreover, little or no research has been done on assessing vegetation health while utilizing multi-date hyperspectral images.In this study, the method for assessing forest health conditions using optical indices retrieved from hyperspectral data was applied to the two temporal HyMap date sets acquired in 07/2009 and 08/2010 to detect stress for the Norway spruce forests in Sokolov, NW Bohemia, a region affected by long-term extensive mining. The classification results were validated by ground truth data (total chlorophyll – Cab, carotenoids – Car and carotenoid to chlorophyll ratio – Car/Cab) and were associated with the geochemical conditions of the forest stands. Both biochemical analysis of the sampled foliage and classification of 2009 and 2010 hyperspectral image identified the same sites affected by vegetation stress. In addition to higher Car/Cab, which enabled detection of the stressed trees using hyperspectral image data, these sites showed critically low pH and lower values for the macronutrient parameters in both organic horizons and, in addition, both sites exhibit critically low base cation to aluminum ratios (Bc/Al) for lower organic and top mineral (0–20 cm) soil horizons.The results of this study demonstrate (i) the potential application of hyperspectral remote sensing as a rapid method of identifying tree stress prior to symptom expression, and (ii) the added value of multi-temporal approaches for hyperspectral data and its further potential for monitoring forest ecosystems.  相似文献   
23.
A water/salt system in an evaporative environment is both a physicochemical region and a biological one. All the parameters of the system, such as the salinity, temperature and CO2 partial pressure, are affected by halo-philic bacteria. The system controls salt deposition but is modified by an accompanying ecological system; therefore it should be called a water/salt/biological system. Salt minerals result from accumulation of the remains of bacteria/algae, namely, bacteria/algae formation; whereas biological, biophysical and biochemical processes provide full evidence for organic involvement. Consequently, salt deposits should not be called purely chemical but biological/chemical ones. This new argument supplements and develops the traditional idea and helps perfect the mineralization theory of salts and even general deposits, thus giving guidance to prospecting for salt deposits.  相似文献   
24.
不同盐度对螺旋藻的生长和生化成分影响的研究   总被引:1,自引:0,他引:1  
用半咸水驯化钝顶螺旋藻获得耐盐品系,在半咸水中盐度驯化的品系的生长率高于未驯化的品系。在不同的盐度的半咸水中盐度驯化品系更能适应较高盐度的半咸水,在20×10-3的盐度下收获量最高。  相似文献   
25.
中国三稀矿产生物找矿技术方法及其应用综述   总被引:1,自引:0,他引:1  
于扬  王登红  高娟琴  刘丽君  王伟  张塞 《地质学报》2019,93(6):1533-1542
生物地球化学作为全球热点学科之一,为找矿工作者探索地壳发生的地质地球化学过程提供了新的理论与方法,开展“三稀矿产”生物找矿方法研究并将其应用到找矿实践工作中,将对资源、环境领域的研究和应用产生重要影响。三稀矿产的生物找矿方法包括地植物学(植被观察)、生物地球化学找矿(植物分析测试)、动物找矿以及微生物找矿四个方面。本文通过归纳、总结前人研究成果,梳理了当前国内三稀矿产生物找矿研究的特点、概念和内涵,归纳了三稀矿产资源生物找矿常用方法,包括采样、测试和综合分析技术方法,总结了生物找矿方法在稀有金属矿区、稀散金属矿区的应用与研究进展,并结合项目团队最新成果,提出了对中国三稀矿产生物找矿方法及其应用的几点新认识,进一步阐述了三稀矿产生物找矿的理论与实际应用意义。通过川西地区锂铍稀有金属生物找矿方法应用于辅助隐伏矿床勘查,已取得一些成功案例。随着研究的深入,生物找矿方法必将对我国三稀矿产地球化学勘查理论和技术发展产生重大影响。  相似文献   
26.
以2龄马氏珠母贝为材料,建立S1(对照组)、S2(术前处理后不插核)、S3(术前处理后插核)和s4(不做术前处理直接插核)四个试验组,每组500个个体。比较研究了术前处理和休养期间各组软体部干重和糖、脂肪、蛋白质含量的差异。试验结果如下:(1)术前处理后,S2和S3组软体部干重显著小于S1组(P〈0.05);S2组短期休养后恢复到S1组水平:S3组在休养期结束后仍然显著小于S1组(P〈0.05)。(2)插核后,S4组软体部干重显著小于S1组(p〈0.05);休养20天后恢复到S1组水平;(3)术前处理后,S2和S3组的软体部糖、脂肪含量明显下降。(4)插核后,S4组的软体部糖、脂肪含量明显下降。(5)试验期间,各组蛋白质含量总体呈上升趋势。结果表明术前处理能够有效降低育珠贝的生理活性:术前处理的马氏珠母贝表现出补偿生长效应,并在营养限制或创伤后的恢复过程中,首先利用体内储存的糖原和脂肪。  相似文献   
27.
Abstract: Major, trace, and rare earth element contents were determined for sedimentary iron ores from the Gunma iron deposit. The deposit was precipitated from a spring water on the hillside of the active Kusatsu-Shirane Volcano. The ores are mainly composed of goethite and jarosite with various proportions of silicified andesitic detritus. Microbial fossils are often preserved well in goethite-rich ores. Goethite was likely precipitated by both inorganic and biogenic (biologically induced mineralization; BIM) processes, whereas jarosite was precipitated inorganically from the spring water. Si, Ti, Al, Mn, Mg, Ca, Na, Co, Rb, Y, Zr, Nb, Hf, Ta, U, and middle-heavy REEs (Sm-Lu) in the ores are dominantly derived from a detrital component (silicified andesitic rocks). On the other hand, Zn and V are likely to have been inorganically coprecipitated with goethite. Preferential uptake of P, Sc, Cu, Mo, Ba, Th, and light REEs occurs in the BIM ores. Unique enrichment of these elements is a promising indicator of biomineralization for ancient sedimentary iron deposits.  相似文献   
28.
【目的】探究二氧化碳CO2麻醉协同低温对卵形鲳鲹有水保活的影响,延长卵形鲳鲹(Trachinotus ovatus)的保活时间。【方法】研究保活过程中CO2质量浓度、麻醉时间、麻醉温度和鱼质量水比对卵形鲳鲹有水保活时长的影响;在最佳麻醉保活条件下,测定其血清生化指标、肌肉及肝脏氧化应激指标及代谢指标。【结果】卵形鲳鲹在16℃、100 mg/L CO2水溶液中麻醉3 min其麻醉效果最佳。在15℃低温下进行有水保活,鱼水质量比为2∶1,存活时间最长,为(359±2)min,此条件下复苏率达100%。经过CO2麻醉协同低温有水保活后的卵形鲳鲹血清谷草转氨酶(GOT)活性显著升高(P<0.05)、尿素氮(BUN)和甘油三酯(TG)含量上升,血糖含量下降。肌肉中的乳酸脱氢酶(LDH)活性显著上升(P<0.05),乳酸(LD)和糖原含量上升,过氧化氢酶(CAT)活性和丙二醛(MDA)含量下降;肝脏中的LDH活性显著上升(P<0.05)、CAT活性和LD的含量上升,MDA和糖原的含量下降。【结论】CO2协同低温有水对卵形鲳鲹有较好的麻醉效果,有助于保活运输。在保活过程中卵形鲳鲹通过提升能量代谢水平和抗氧化能力应答环境应激,在一定程度上影响卵形鲳鲹保活过程的存活时间。  相似文献   
29.
奇尔古斯套组硅质岩SiO2含量较高,Al2O3、TiO2含量变化较大,反映出较多的外来物质的加入;Si/ (Al+Fe+Mn)、Al/ (Al+ Fe+ Mn)、MnO/TiO2、Al2 O3/(Al2 O3+ Fe3 O2)值较高,反映其为生物化学成因,形成于大陆边缘环境;Fe2O3/TiO2对Al2O3/(Al2 O3+ Fe2O3)图解同样说明其形成于大陆边缘环境.REE较高,HREE富集不明显,北美页岩标准化后的稀土配分模式曲线较为平坦,向左倾斜不明显,(La/Ce)shale值较低,δCeshale值较高,无明显Ce负异常,反映奇尔古斯套组硅质岩属生物化学成因硅质岩,形成于大陆边缘环境; (La/Ce)shale对Al2 O3/(Al2 O3+Fe2 O3)图解亦说明其形成于大陆边缘环境.微量元素中Hf含量高,而Be、Li、Nb、Rb、Sr、Ta、Th、U、V、Zr含量低;Ba元素含量低;Co、Ni贫富相当,Co/Ni值较高,U/Th值低,说明奇尔古斯套组硅质岩属于正常的生物化学成因的硅质岩.  相似文献   
30.
对虾冷藏过程中肌肉蛋白特性的变化比较   总被引:1,自引:0,他引:1  
从生物化学、物理学两方面,比较养殖对虾和海捕对虾在冷冻贮藏过程中肌动球蛋白的特性变化,探讨不同贮藏温度和时间对蛋白特性的影响,及特性指标之间的相关性。冷藏后AM溶解度下降,ATPase活性下降,总SH和未遮盖SH数均减少,疏水性增大,而ATP感度呈下降趋势。所有指标变化表明随着冻藏时间的延长,蛋白质变性加剧,变性程度为-10℃>-18℃>-30℃。各项指标均显示养殖对虾蛋白质的耐冻性比海捕对虾弱。  相似文献   
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