末次盛冰期以来中国陆地生态系统碳储量变化研究

Carbon is an essential element for life, food and energy. It is also a key element in the greenhouse gases and therefore plays a vital role in climatic changes. The rapid increase in atmospheric concentration of CO_2 over the past 150 years, reaching current concentrations of about 370 ppmv, corresponds with combustion of fossii fuels since the beginning of the industrial age. Conversion of forested land to agricultural use has also redistributed carbon from plants and soils to the atmosphere. These human activities have significantly altered the global carbon cycle. Understanding the consequences of these activities in the coming decades is critical for formulating economic, energy, technology, trade, and security policies that will affect civilization for generations. Under the auspices of the International Geosphere-Biosphere Programme (IGBP), several large international scientific efforts are focused on elucidating the various aspects of the global carbon cycle of the past decade. It is only possible to balance the global carbon cycle for the 1990s if there is net carbon uptake by terrestrial ecosystems of around 2 Pg C/a. There are now some independent, direct evidences for the existence of such a sink. Policymarkers involved in the UN Framework Convention on Climate Change (UN-FCCC) are striving to reach consensuses on a 'safe path' for future emissions, the credible predictions on where and how long the terrestrial sink will either persist at its current level, or grow/decline in the future, are important to advice the policy process. The changes of terrestrial carbon storage depend not only on human activities, but also on biogeochemical and climatological processes and their interaction with the carbon cycles. In this thesis, the climate-induced changes and human-induced changes of carbon storage in China since the past 20,000 years are examined. Based on the data of the soil profiles investigated during China's Second National Soil Survey (1979-1989), the forest biomass measured during China's Fourth National Forest Resource Inventory (1989-1993), the grass biomass investigated during the First National Grassland Resource Survey (1980-1991), and the data collected from a collection of published literatures, the current terrestrial carbon storage in China is estimated to -144.1 Pg C, including -136.8 Pg C in soil and -7.3 Pg C in vegetation. The soil organic (SOC) and inorganic carbon (SIC) storage are -78.2 Pg C and -58.6 Pg C, respectively. In the vegetation reservoir, the forest carbon storage is -5.3 Pg C, and the other of-1.4 Pg C is in the grassland. Under the natural conditions, the SOC, SIC, forest and grassland carbon storage are -85.3 Pg C, -62.6 Pg C, -24.5 Pg C and -5.3 Pg C, respectively. Thus, -29.6 Pg C organic carbon has been lost due to land use with a decrease of -20.6%. At the same time, the SIC storage also has been decreased by -4.0 Pg C (-6.4%). These suggest that human activity has caused significant carbon loss in terrestrial carbon storage of China, especially in the forest ecosystem (-76% loss). Using the Paleocarbon Model (PCM) developed by Wu et al. in this paper, total terrestrial organic carbon storage in China in the Last Glacial Maximum (LGM) was -114.8 Pg C, including -23.1 Pg C in vegetation and -86.7 Pg C in soil. At the Middle Holocene (MH), the vegetation, soil and total carbon were -37.3 Pg C, -93.9 Pg C and -136.0 Pg C, respectively. This implies a gain of-21.2 Pg C in the terrestrial carbon storage from LGM to HM mainly due to the temperature increase. However, a loss of-14.4 Pg C of terrestrial organic carbon occurred in China under the current condition (before 1850) compared with the MH time, mainly due to the precipitation decrease associated with the weakening of the Asian summer monsoon. These results also suggest that the terrestrial ecosystem in China has a substantial potential in the restoration of carbon storage. This might be expected to provide an efficient way to mitigate the greenhouse warming through land management practices. Assuming that half of the carbon loss in the degraded terrestrial ecosystem in current forest and grass areas are restored during the next 50 years or so, the terrestrial ecosystem in China may sequestrate -12.0 Pg of organic carbon from the atmosphere, which represents a considerable offset to the industry's CO2 emission. If the ' Anthropocene' Era will be another climate optimum like MH due to the greenhouse effect, the sequestration would be increased again by -4.3 - 9.0 Pg C in China.

瓦里关山与观风山近地面空气^7Be浓度季节性变化对比

^7Be广泛应用于大气物质传输、表土季节性迁移和微粒混合作用的示踪。它在不同地域空气中的浓度分布构成了多领域研究的基础。^7Be在对流层空气中的浓度随地表海拔高度而增加。基于瓦里关山和观风山的位置差异和海拔高差，对比观测其近地面空气^7Be浓度变化不仅有益于区域尺度的大气和地表环境过程的示踪，而且对全球尺度的研究也将具重要意义。2002-10-09～2004-01-21，利用美国环境测量实验室的低水平核素表层大气采样系统在瓦里关山和观风山同步连续进行每周1个大气气溶胶样品的采集工作。^7Be的比活度系用多道能谱仪进行1谱测定，测量误差小于6％。中美两实验室对逐周样品测量结果表明两实验室的数据具有很好的可比性。两个站点^7Be浓度逐周变化趋势总体相似，具有2～6周的短周期波动，波峰与波谷具有良好的对应关系，其高值或低值波动延迟或超前的差异与区域尺度的天气过程传播一致。瓦里关山和观风山，Be的年均浓度分别为（14．7±1．5）mBq／m^3和（4．1±0．9）mBq／m^3，前者约为后者的3．6倍。近地面空气^7Be浓度与同期降水量的比较表明，在周时间尺度上，两者呈现出较好的预期负相关变化；而在月平均尺度上，两地^7Be浓度变化比较稳定。位于内陆地区的瓦里关山受低海拔气团上升的影响较小，其空气中^7Be浓度变化较真实地反映了中纬度、高海拔地区的背景水平。观风山地区虽然受到低纬度海洋性上升气团的影响，但^7Be浓度变化仍然显示出低纬度、较高海拔地区的预期水平。[^7Be广泛应用于大气物质传输、表土季节性迁移和微粒混合作用的示踪。它在不同地域空气中的浓度分布构成了多领域研究的基础。^7Be在对流层空气中的浓度随地表海拔高度而增加。基于瓦里关山和观风山的位置差异和海拔高差，对比观测其近地面空气^7Be浓度变化不仅有益于区域尺度的大气和地表环境过程的示踪，而且对全球尺度的研究也将具重要意义。2002-10-09～2004-01-21，利用美国环境测量实验室的低水平核素表层大气采样系统在瓦里关山和观风山同步连续进行每周1个大气气溶胶样品的采集工作。^7Be的比活度系用多道能谱仪进行1谱测定，测量误差小于6％。中美两实验室对逐周样品测量结果表明两实验室的数据具有很好的可比性。两个站点^7Be浓度逐周变化趋势总体相似，具有2～6周的短周期波动，波峰与波谷具有良好的对应关系，其高值或低值波动延迟或超前的差异与区域尺度的天气过程传播一致。瓦里关山和观风山，Be的年均浓度分别为（14．7±1．5）mBq／m^3和（4．1±0．9）mBq／m^3，前者约为后者的3．6倍。近地面空气^7Be浓度与同期降水量的比较表明，在周时间尺度上，两者呈现出较好的预期负相关变化；而在月平均尺度上，两地^7Be浓度变化比较稳定。位于内陆地区的瓦里关山受低海拔气团上升的影响较小，其空气中^7Be浓度变化较真实地反映了中纬度、高海拔地区的背景水平。观风山地区虽然受到低纬度海洋性上升气团的影响，但^7Be浓度变化仍然显示出低纬度、较高海拔地区的预期水平。

中国东南部赣杭构造带基性岩浆活动及其意义

中国东南部晚中生代以来的动力学背景一直受到大量学者的关注，特别是大陆岩石圈地幔和大规模岩浆活动事件。华南地区广泛发育的基性脉岩，为研究中国东南部动力学背景提供了载体。前人分别从年代学、矿物学、岩石学和地球化学等方面对广布于华南（福建、广东、江西、海南、湖南等地区）基性岩进行了详细研究，并取得了许多重要成果。 赣杭构造带地处一级大地构造单元扬子地块和华夏地块结合部位，横跨江南元古宙岛弧和华南加里东造山带两个二级构造单元，长期控制两侧地质构造、岩浆活动、沉积、变质及成矿作用。带内发育的基性岩为认识构造带活动情况提供可能。但目前对构造带内的基性岩浆活动的研究较少，应用系统的矿物学、元素和同位素地球化学及同位素年代学等研究方法，对赣杭构造带中生代以来的基性岩体及基性脉岩进行了系统研究。并应用其形成时代、源区性质等结论对中国东南部岩石圈伸展减薄、地幔性质等地球动力学背景中的问题进行探讨。主要取得以下几点认识： 1. 系统进行资料收集，并在此基础上进行野外考察和采样，明确了赣杭构造带发育基性岩的岩石类型主要为辉长岩，辉绿岩及橄榄辉绿岩。主要分布在构造带的南侧，受主/次断裂控制明显。 2. 明确赣杭构造带基性岩体主要为辉长岩，落在粗面玄武岩-玄武岩-玄武粗面安山岩，碱性-亚碱性范围内各有分布，但以亚碱性居多。SiO2范围从45.11-53.47 wt%，MgO的范围从4.06-9.28 wt%，TiO2的范围从0.79-3.63 wt%。微量元素总体富集大离子亲石元素（LILE）（Ba、Rb）、轻稀土（LREE），而亏损高场强元素（HFSE）（Ta、Nb、Zr、Hf、Ti）和重稀土元素（HREE）。余江、东乡、枧头、虎头等近构造带样品，岩浆来源与OIB近似，Nb、Ta亏损不明显。岩浆源区地幔性质从亏损地幔向富集地幔都有分布，流体熔体的交代作用及地壳物质参与可能是造成富集程度不同的主要原因。基性岩体未受到明显的地壳混染，主要经部分熔融形成，成岩过程中发生了橄榄石和单斜辉石的分离结晶作用。构造带对岩浆源区及深部壳幔物质演化发挥重要作用，还控制着岩浆的上升侵入。 3. 赣杭构造带基性脉岩主要为辉绿岩类，在玄武岩-玄武安山岩范围内，碱性-亚碱性范围内都有分布，以亚碱性占大多数。SiO2的范围从44.44-54.73 wt%，MgO的范围从2.74-7.89 wt%，TiO2的范围从0.91-3.39 wt%。微量元素总体富集大离子亲石元素（LILE）（Ba、Rb）和轻稀土元素（LREE），而亏损高场强元素（HFSE）（Ta、Nb、Zr、Hf、Ti）。基性岩脉经不同程度部分熔融作用形成，且成岩过程中经历了橄榄石、单斜辉石及少量斜长石的分离结晶作用。样品没有受到明显的地壳混染现象。基性脉岩的源区性质与流体熔体交代作用及地壳物质参与有关。少量下地壳以拆沉形式加入了原始地幔，进而通过流体熔体交代作用，造成了原始地幔的富集。伸展活动的逐渐加大及软流圈的上涌为拆沉提供了有利条件。赣杭构造带对岩浆源区、深部壳幔物质演化及岩浆上升侵入影响显著。 4. 赣杭构造带岩浆活动发育呈现多元化特点，Sr-Nd-Pb同位素特征显示有EMⅡ的参与。流体交代特征比较复杂，源区存在金云母和金红石的交代，进一步说明下地壳成分参与了壳幔相互作用。同位素模拟表明古老基底通过源区混合也有所参与。结合前人的研究，提出了本区的成岩模式。赣杭构造带地区伴随岩石圈伸展作用的进行，发生了岩石圈减薄及软流圈地幔的上涌作用，少量下地壳物质拆沉到岩石圈地幔参与了岩浆的形成，构造带重新活化及活动对岩浆形成制约明显。新生代岩石圈地幔对中生代岩石圈地幔继承和改造。 5. 根据K-Ar年龄并结合区域内已有同位素年龄，赣杭构造带上的基性岩具有周期性分布特点，初步分为±180 Ma、145-150 Ma、120-140 Ma、95-110 Ma和65-80 Ma五组，且以120-140 Ma和95-110 Ma的峰值最为集中，代表了赣杭构造带岩浆活动最为强烈的期次。据目前研究，145 Ma限定了中国东南岩石圈伸展作用开始作用的下限，随着研究深入，更早能准确指示转换年龄的证据可能会被发现。大于140 Ma的岩浆比较偏向于构造体制转换下的构造-岩浆活动产物，与岩石圈的减薄及软流圈上涌关系密切。整个华南的岩石圈伸展作用对大规模金属成矿意义明显。赣杭构造带在热源、流体来源及驱动机制等方面对区内的以铀为主的金属成矿作用起到了制约。

广西贺县龙水金矿床的同位素地球化学研究及成因探讨

广西贺县龙水金矿位于湘桂稳定区，桂粤交界山脉的北段，博白-茶陵深断裂的西侧，区内广泛发育加里东期到燕山期的花岗岩，出露的基底地层主要为震旦系到寒武系。本文主要研究龙水金矿II号矿化带。该带位于寒武系水口群清溪亚群和大宁花岗闪长岩体的接触带附近，围岩为寒武系的碳质板岩，矿脉为硫化物石英脉，主要有黄铁矿、方铅矿、闪锌矿和石英等矿物。金矿化与硫化物密切相关。主要的金矿物为银金矿，少许自然金。确定金矿床的成矿年龄一直是个比较刺手的问题。本文选择矿脉中信为是成矿期的石英作为Rb-Sr等时年龄测定的对象，是基于其纯净和其中的原生气液包体基本可代表成矿热液的特征。结果表明其Rb-Sr等时年龄为120.5Ma，并认为此年龄代表了成矿年龄。有石英Rb-Sr等时线的~(87)Sr/~(86)Sr初始比为0.732089, 与矿脉中碳酸相加矿物的Sr同位素比值（约为0.7337-0.7402）一起，表明Sr应是来自地壳的富Rb盐矿物的Sr源区。另外，为了与围岩的蚀变年龄对比，测定了近矿围岩的Rb、Sr同位素组成，结果形成两条等时线，年龄分别为245.9 Ma和173.6 Ma，表明成矿以前至少发生了两次地质事件，导致了Sr同位素的均一化。这两次地质事件分别与华南的东吴运动及燕山运动第一幕相对应。矿石Pb同位素的~(206)Pb/~(204)Pb、 ~(207)Pb/~(204)Pb 和~(208)Pb/~(204)Pb 分别在18.4-18.9、15.6-16.1和38.4-39.6的范围内，并在~(207)Pb/~(204)Pb vs ~(206)Pb/~(204)Pb坐标图上呈现出斜率为1左右的线性排布。只有个别数据点要以得出依据Doe模式的模式年龄，约为200 Ma。在Zart,am Pb构造模式中，矿石Pb同位素数据大部分位于上地壳Pb线以上，呈现出富放射性成因Pb的特征。为了解释异常Pb的成因，本文进行了定量计算。结果表明矿石Pb为古老的存留地壳Pb与少地幔源Pb的混合，即矿石Pb同位素经历了这样的演化过程：在39-29.8亿年间由地幔分异出的地壳 Pb，未参与壳幔循环作用，一直到燕山期，与少量幔源Pb混合，并加入成矿。混合μ值为9.85-10.22。矿石的地质情况及矿石Pb同位素的Δα-Δβ-Δγ示踪结果均支持这一结论。本文初次研究了脉石英中的U、Pb同位素组成。脉石英中Ｕ含量很低。Pb同位素组成基本可以划分为两组，一组为与方铅矿数据近似的普通Pb组成，另一组则较富放射性成因Pb，并向围岩的Pb同位素组成漂移，可能是随着热液的演化和大气降水的加入，受围岩Pb的影响所致。矿脉中硫化物样品的S同位素比值（加权平均为0.16‰）和碳酸盐矿物样品的C同位素比值（在-0.1～-4.1‰的范围内），表明其应为内生来源。根据脉石英的气液包体均一温度（180-250 ），计算与脉石英存在0同位素平衡的热液的同位素的同位素组成，结果为1.2～-4.8‰，表明有大气降水的参与。石英气液包体水溶液为弱碱性，其成分分析表明其中K_2O/Na_2和CaO/MgO（分别根据K~+/Na~+和Ca~(2+)/Mg~(2+)的换算）与围岩相差很大。另外，矿石中微量元素主要为Au、A2g、Cu、Pb、Zn、Co、Ni、Mo、Bi、Ga、As、Sb、和Hg，而围岩中微量元素则主要为Cu、Ni、Mn、V、Zr、Ti、Cr和Ba。因此，热液中成矿元素主要不是来自围岩。黄铁矿的Co/Ni、S/Se/的比值可以指示热液化的来源。龙水金矿矿脉中黄铁矿的Co/Ni > 1，S/Se < 15000，均在与岩浆作用有关的热液范围内。因此，热液活动应主要与岩浆岩有关。矿石、围岩和花岗闪长岩的稀土配分模式相似，均呈现向右倾斜的V字型，并且类似于太古代后沉积岩。结合Pb、Sr同位素的研究，推测花岗闪长岩的源岩主要为古老的地壳物质。概括起来，龙水金矿床为约120.5 Ma形成的中低温热液矿床；热液中成矿物质主要来自花岗闪长岩。由于围岩与矿床紧密的空间联系及围岩中的高Au含量，围岩可能提供了一部分Au及其他成矿物质。

中老年危机热线来电者的应激源与自杀危险性

Objective: Psychosocial crisis and psychiatric disorders are two stressors for suicide action. This study will explore the differences on demographic characteristics, severity of depression, and suicidality of middle-aged and elder crisis line callers under the influences of psychosocial crisis or psychiatric disorders or two simultaneously-mixed stressors, in order to develop effective intervention strategies for crisis line. Methods: Analysis data of 1,092 cases selected from national crisis line callers aged 45 and over who were assessed with “Suicide risk assessment” during the period from December, 2002 to December, 2008. The sample were divided into three groups of psychosocial crisis, mental health problems, and mixed-stressors of three types of general callers (48.2%, 32.3%, 19.5%), callers with current suicide ideation (43.7%, 33.0%, 23.3%) and callers attempted suicide 2 weeks prior to the call (33.6%, 42.3%, 24.1%) respectively according to the operators’ judgments of the callers’ claimed difficult situations and classification system of crisis line database. X2 test and Tukey-type and Multinomial Logistic Regression multiple comparison methods are applied to analysis the differences of the three groups. Results: In agreement with previous studies, more females (71.3%, X2=13.45, P<0.001), especially females influenced by relationship stressors (76.8%, X2=25.12, P<0.001) made the call for crisis. Among general callers, the check-out rates of Major Depression Episode of mixed-stressor callers (78.5%, P<0.001) and problem callers (68.7%, P<0.05) were significantly higher than that of crisis callers (57.1%). The check-out rates of suicide ideation of mixed-stressor callers (71.4%) were significantly higher than that in crisis callers (53.8%, P<0.001) and problem callers (60.9%, P<0.05). The check-out rates of prior suicide attempts of mixed-stressor (16.6%, P<0.05) and problem callers (18.5%, P<0.01) were significantly higher than that of crisis callers (9.8%). More than half of the mixed-stressor callers (51.8%) reported over 50% degree of hopelessness, which was significantly higher than that of crisis callers (35.6%, P<0.01) and problem callers (38.2%, P<0.05). Fewer crisis callers sought medical help than problem and mixed-stressor callers among three types of callers (X2=241.35, 146.56, 50.87; P<0.001). Compare to non-compound crisis callers, the proportion of minor, severe depression and prior depression diagnosis (14.0% vs. 17.4%; 54.9% vs. 65.2%; 0 vs. 2.2%; X2=14.35，P<0.01), suicide ideation (51.1% vs. 64.0%, P<0.05) and prior suicide attempts (8.4% vs. 15.0%, P<0.05) in compound crisis callers were significantly higher. There were more compound crisis callers with over 50% hopelessness (51.9% vs. 31.0%，X2=11.96，P<0.01). Conclusion: As predicted, among middle-aged and elderly participants, mixed-stressor and compound crisis callers were higher in degree of severity of depression and suicidality. Intervention strategies should be developed addressing to specific stressor or stressors. The promotions of crisis callers’ medical help seeking behavior need to be emphasized.

7-11岁正常儿童和ADHD儿童故事重述能力及策略的发展

儿童的故事重述涉及工作记忆和抽象表征能力，是与儿童的日常学业任务密切联系。儿童能否把握时间线索来组织故事重述，反映的是儿童抽象出故事事件内在时间关系的能力，因此对儿童故事重述的探查可以揭示儿童抽象思维发展的一般规律和特点。本研究在前人研究的基础上，系统探查了7－11岁儿童故事重述能力及其策略的发展过程，探讨了时间线索对儿童故事重述的影响，并对ADHD儿童和正常儿童的故事重述及策略进行了比较。 主要研究结果如下： (1)7－11岁儿童故事重述能力总体上随年龄增长而提高，按正确顺序重述的事件数量增多，重述过程中提取和使用的时间线索也增加。其中7－9岁有较快速的发展。 (2)随故事中包含的事件数量的增加，故事难度增大，儿童的故事重述成绩有所下降，故事长度对7岁和9岁儿童的影响大于对11岁儿童的影响。 (3)有、无时间线索语词会影响儿童的故事重述。故事中包含时间语词线索有助于儿童的故事重述。11岁儿童的故事重述已不受有、无时间线索的影响，他们在无时间线索的条件下，更多地主动使用表示因果关系的语词来表征事件关系。 (4)ADHD儿童的故事重述能力在9岁到11岁有较快的发展。但总体而言，ADHD儿童对含有时间线索故事的重述能力显著差于正常儿童。 (5)故事再学习对ADHD儿童和正常儿童的故事重述都存在促进作用。但ADHD儿童故事再学习效果不如正常儿童，低龄儿童中差距尤其明显，随着年龄的增加，ADHD儿童与正常儿童故事再学习效果的差距逐渐缩小。 (6)不同年龄的儿童主要采用四种策略解决问题。随年龄增长，正常儿童和ADHD儿童中使用水平较高的内容主线和逻辑关系策略的人数都有所增加。但ADHD儿童中高水平策略使用人数比例仍低于正常儿童。