混积岩分类命名体系探讨及对混积岩储层评价的启示——以渤海海域混积岩研究为例

混积岩是一种普遍而重要的岩石组合类型。然而长期以来,对混积岩的岩石学分类与命名一直存在诸多争议,且尚未有统一的分类体系与命名规则。本文结合渤海海域混积岩岩石薄片组分鉴定、岩石储层物性分析等最新研究成果,并与相关文献结合,最终确立以陆源碎屑物、生物成因碳酸盐颗粒、化学沉淀碳酸盐为三组分端元的一套新的混积岩岩性分类体系,并将混积岩分为4大类、16亚类。通过讨论混积岩混积层系及混积岩组构界定的问题,进一步完善了混积岩定义。利用新的岩石学分类方案,可为储层评价研究提供指导。以渤海海域为例,建立起研究区不同岩性相与储层物性的对应关系,并在岩性分类体系中划分出差储层、中等储层及优质储层三个储层区。     

1965-2015年新疆夏季不同等级降水的空间分布特征

根据新疆51个台站1965-2015年夏季逐日降水资料,将降水划分为小雨、中雨及大雨3个等级,分析了新疆近51 a夏季不同等级降水量、降水日数及降水强度的空间分布特征,并讨论了各等级降水日、降水量及降水强度与总降水量的空间相似程度以及各等级降水对夏季总降水的贡献。结果表明：新疆降水主要集中在夏季,并以小雨为主。以天山山脉为界,南北两疆降水空间分布存在明显差异,北疆夏季降水量（日）占年降水量（日）的36%~45%（36%~39%）,南疆夏季降水量（日）占年降水量（日）的51%~63%（48%~60%）;新疆夏季不同等级降水量、降水日及降水强度的空间分布不均匀。新疆夏季总降水量与各等级降水量的空间相似系数最为密切,与各等级降水强度的空间相似系数相对较小;新疆夏季小雨贡献率最大,中雨其次,大雨最小,夏季降水量和降水日的变化主要受小雨的影响。     

铺前—清澜断裂西支晚更新世活动特征

海域浅层地震探测调查表明,铺前—清澜断裂向北西海域方向延伸,断裂走向NW-SE,倾向SW,为高倾角的正断层;在地震剖面上,断裂断错了第四系地层;进一步应用钻探技术对铺前—清澜断裂进行探测研究,结合层序地层学、岩性岩相分析与年代测定等方法建立了钻孔联合剖面,揭示断层性质为正断层,倾向SW,断距4.0 m,断层的最新活动时代为晚更新世,第四纪表现为张性活动,断裂的平均垂直速率为0.15 mm/a。     

长春地区粉质黏土导热系数与其物性参数相关性研究

为研究导热系数与影响因素之间的相关关系,建立导热系数的推算公式,以长春地区粉质黏土为研究对象,对原状土样的导热系数与其物理参数之间的相关性进行回归分析。制作9个重塑土样,测其相关的参数值,以验证回归方程的适用性。结果表明,回归分析建立导热系数与2个物理参数之间的关系式不成立;考虑天然密度、含水率和孔隙度为自变量,其分别对应的相关性系数T检验显著值(Sig)都0. 05,复决定系数为0. 886,建立的回归方程成立,自变量能准确解释因变量的变化,且含水率与导热系数呈负相关,天然密度和孔隙度呈正相关。重塑土样相关参数代入回归方程得到的导热系数值与实验实测值之间相对误差低于4%,验证了该回归方程的普遍性和适用性。     

逻辑回归模型在边坡稳定性分析中的应用

采用逻辑回归模型和确定性系数CF建立概率模型,使用收集到的22个边坡实例,将重度、内聚力、坡角、坡高、内摩擦角和孔隙压力比六个影响因子作为自变量,边坡状态作为因变量,应用SPSS取不同的滑坡概率P与不滑坡概率1-P的比值的自然对数Z进行回归分析。将获得的滑坡概率拟合模型反馈到样本参数上,对比其误差,选取Z=±10时的函数模型对另外8组边坡进行验证,证明预测模型的合理性。     

Mid-Cretaceous Hothouse Climate and the Expansion of Early Angiosperms

The remarkable transition of early angiosperms from a small to a dominant group characterized the terrestrial ecosystem of the Cretaceous. This transition was instigated and promoted by environmental changes. Mid-Cretaceous is characterized by major geological events that affected the global environment. δ18O, palaeothermometer TEX86, and other climatic indices from marine sediments suggest rapid temperature increase during mid-Cretaceous despite occasional short cooling events. Simultaneously, terrestrial deposits in East Asia changed from coal-bearing to shale, then to red beds and evaporites. Plant assemblages and other paleoclimate indicators point to rapid aridification for mid-Cretaceous terrestrial environments. In addition, the wildfires were frequently spread all over the earth by the numerous charcoal evidence during the Mid-Cretaceous. Thus, we speculate that the seasonally dry and hot conditions of mid-Cretaceous created a fiery hothouse world. Early angiosperms increased in abundance and diversity and evolved from a few aquatic species to terrestrial herbaceous and then to the diversified flora of today. Angiosperms showed rapid physiological evolution in vein density and leaf area that improved photosynthesis and water absorption. These ecophysiological changes made early angiosperms well adapted to the hot and dry environment in mid-Cretaceous. Moreover, these physiological changes facilitated the fire–angiosperm cycles in mid-Cretaceous that likely further stimulated the early angiosperm evolution.     

不同方法评价喀斯特煤矿区农田土壤重金属生态风险比较

采用TCLP法、内梅罗综合污染指数、嵌入Igeo综合污染指数法等方法对贵州织金县某煤矿区周边农田土壤重金属进行评价。土壤中Cd、Cr、Cu、Ni、Hg和Zn的含量范围分别为0.79～2.08 mg·kg-1、144.20～464.40 mg·kg-1、91.63～187.50 mg·kg-1、48.13～104.47 mg·kg-1、0.14～2.33 mg·kg-1、144.35～265.89 mg·kg-1,所有土壤样点的Cd、Cr、Cu和Ni含量均已超过国家土壤环境质量二级标准,部分土壤样点的Hg和Zn含量超过二级标准。TCLP法评价结果所有土壤样点均未受到重金属污染;内梅罗综合污染指数法评价结果为农田土壤重金属生态风险处于安全水平;嵌入Igeo综合污染指数法评价结果表明,90%的土壤达到中度污染以上,其中65%的土壤处于中度污染,25%的土壤受到中度至重度污染;潜在生态危害指数法评价表明,所有土壤样点重金属均处于轻微生态风险水平。针对不同评价方法得出的结果存在差异的情况,在评价土壤重金属污染状况时,应根据评价目标的差异选择合适的评价方法。      

Satellite estimates and subpixel variability of rainfall in a semi-arid grassland

卫星估雨精度的不确定性受到当地降雨类型和像元内降雨非均匀性影响,而结合这两个关键因素开展半干旱草原卫星估雨的研究有限.2009年夏,我们在中国锡林郭勒半干旱草原用多部微雨雷达和雨量计构建了9 km卫星像元降雨观测网,观测了像元内降雨非均匀性(空间变异系数CV),并评估了卫星估雨精度.结果表明:(1)CV值受像元内平均降雨量,降雨类型,降雨云面积及移向等影响,如高Cv值的降雨过程大多为平均降雨量小,对流性降雨过程,降雨云边缘像元CV值较高;(2)TRMM 3B42V7卫星估雨产品适用性较好,CMORPH和PERSIANN次之,但TRMM 3B42V7易在半干旱草原湖泊处高估降雨.     

Carbon costs and benefits of France’s biomass energy production targets

Background

Concern about climate change has motivated France to reduce its reliance on fossil fuel by setting targets for increased biomass-based renewable energy production. This study quantifies the carbon costs and benefits for the French forestry sector in meeting these targets. A forest growth and harvest simulator was developed for French forests using recent forest inventory data, and the wood-use chain was reconstructed from national wood product statistics. We then projected wood production, bioenergy production, and carbon balance for three realistic intensification scenarios and a business-as-usual scenario. These intensification scenarios targeted either overstocked, harvest-delayed or currently actively managed stands.

Results

All three intensification strategies produced 11.6–12.4 million tonnes of oil equivalent per year of wood-based energy by 2026, which corresponds to the target assigned to French wood-energy to meet the EU 2020 renewable energy target. Sustaining this level past 2026 will be challenging, let alone further increasing it. Although energy production targets can be reached, the management intensification required will degrade the near-term carbon balance of the forestry sector, compared to continuing present-day management. Even for the best-performing intensification strategy, i.e., reducing the harvest diameter of actively managed stands, the carbon benefits would only become apparent after 2040. The carbon balance of a strategy putting abandoned forests back into production would only break even by 2055; the carbon balance from increasing thinning in managed but untended stands would not break even within the studied time periods, i.e. 2015–2045 and 2046–2100. Owing to the temporal dynamics in the components of the carbon balance, i.e., the biomass stock in the forest, the carbon stock in wood products, and substitution benefits, the merit order of the examined strategies varies over time.

Conclusions

No single solution was found to improve the carbon balance of the forestry sector by 2040 in a way that also met energy targets. We therefore searched for the intensification scenario that produces energy at the lowest carbon cost. Reducing rotation time of actively managed stands is slightly more efficient than targeting harvest-delayed stands, but in both cases, each unit of energy produced has a carbon cost that only turns into a benefit between 2060 and 2080.

     

GIS多准则的城市垃圾楼空间布局优化选址

针对城市公共设施的传统选址方法较少考虑空间维度因素的问题,该文提出了基于地理信息系统(GIS)多准则的城市公共设施选址模型,利用GIS多准则技术基于空间维度分析了城市自然环境和人文要素等综合影响下的公共设施选址方法,并以城市垃圾楼选址为例进行了实例应用。实验结果表明:该方法不仅充分考虑了城市复杂的地理环境,还深度探究了影响城市公共设施选址的综合性因素。