常州地区地面沉降及地层压缩性研究

系统分析了常州地区地下水开采动态和地面沉降发生发展历史,概述了研究区地面沉降的框架,在此基础上,系统研究了常州市分层标从1984年至2002年的分层沉降资料。根据常州地区地下水含水层系统及土层特性,将研究区松散土层垂向划分为四个不同层次,分别研究了它们的压缩变形历时特性及其与累计地下水开采量的关系,研究了各自的应变特性。由于土层结构及物理力学性质的不同、地下水开采层次及强度的差异、土层不同应力历史的影响等诸多因素的综合效应,导致了地面沉降及分层压缩特性的显著差别。常州地区的主要压缩层为第II承压含水层的顶板弱透水层,与含水层距离近的土层变形量及应变量均较大,其次是第II承压含水层本身及其与第III承压含水层之间的弱透水层。地面沉降及地层压缩与地下水开采之间的滞后效应在常州地区表现得并不明显,这一点至少在月或年的时间尺度上是正确的。     

断块构造说的形成和发展

断块说形成过程充分表现了张文佑先生广蓄并纳继承创新的治学思路。在1956～1958年主持编纂的1∶5 000 000中国大地构造图及其说明书《中国大地构造纲要》和20世纪80年代初期完成的1∶5 000 000中国及邻区海陆大地构造图及其说明书《断块构造导论》是其发展两大阶段的标志。古中国大陆在断裂体系影响下破碎分离再逐步拼合的过程中形成稳定断块与活动带相间的格局; 拉张造洋挤压造陆,洋、陆型地壳互相转化等两大学术观点的提出是其重大理论创新。断块说在解释中国及邻区大地构造中不断发展并融合了其它学术流派,断块开合说的提出即是其表现之一。立足亚洲-西太平洋复杂的地质构造断块说可望得到进一步发展。     

Deep Fractionation of Clinopyroxene in the East Pacific Rise 13°N: Evidence from High MgO MORB and Melt Inclusions

Mid-ocean ridge basalts (MORBs) from East Pacific Rise (EPR) 13°N are analysed for major and trace elements, both of which show a continuous evolving trend. Positive MgO–Al2O3 and negative MgO–Sc relationships manifest the cotectic crystallization of plagioclase and olivine, which exist with the presence of plagioclase and olivine phenocrysts and the absence of clinopyroxene phenocrysts. However, the fractionation of clinopyroxene is proven by the positive correlation of MgO and CaO. Thus, MORB samples are believed to show a “clinopyroxene paradox”. The highest magnesium-bearing MORB sample E13-3B (MgO=9.52%) is modelled for isobaric crystallization with COMAGMAT at different pressures. Observed CaO/Al2O3 ratios can be derived from E13-3B only by fractional crystallization at pressure >4 ±1 kbar, which necessitates clinopyroxene crystallization and is not consistent with cotectic crystallization of olivine plus plagioclase in the magma chamber (at pressure ~1 kbar). The initial compositions of the melt inclusions, which could represent potential parental magmas, are reconstructed by correcting for post-entrapment crystallization (PEC). The simulated crystallization of initial melt inclusions also produce observed CaO/Al2O3 ratios only at >4±1 kbar, in which clinopyroxene takes part in crystallization. It is suggested that MORB magmas have experienced clinopyroxene fractionation in the lower crust, in and below the Moho transition zone. The MORB magmas have experienced transition from clinopyroxene+plagioclase+olivine crystallization at >4±1 kbar to mainly olivine+plagioclase crystallization at <1 kbar, which contributes to the explanation of the “clinopyroxene paradox”.     

单轴压缩下花岗岩电磁信号的实验研究

利用自主研制的电荷感应仪对花岗岩样品在单轴压缩变形破裂过程中产生的电荷感应信号和磁信号进行了实验研究。实验结果表明,在岩石变形破裂达到峰值强度时比在峰值强度前有更强的电荷感应信号产生,电荷感应信号也受岩石应力的变化速率影响,在应力变化速率大时,有较强的电荷感应信号。在有变形破裂时,电荷感应信号就较强,变形破裂较小的面所对应的测点的电荷感应信号就较小,这表明电荷的产生和岩石的破裂有很大的关系。电信号比磁信号多,在岩石变形破裂时不断有电信号产生,且有明显的变化,而磁信号的变化不明显。电信号相比磁信号受外界的干扰小,幅值大,说明用电荷感应的方法监测岩石的变形破裂前兆更有优势。     

Genetic Aspects of the Manto-type Copper Deposits Based on Geochemical Studies of North Chilean Deposits

Recent studies on mineralogy, geochronology, fluid inclusion and stable isotope (Pb, Os, S, C, O, Sr) characteristics were reviewed to determine constraints for genetic models of the Chilean manto‐type copper deposits. The Chilean manto‐type deposits are divided into the two geologic categories of the northern areas (Arica–Iquique, Tocopilla–Taltal) and the central areas (Copiapó, La Serena, Santiago). The former is distributed in the coastal range composed of Jurassic andesite‐dominated volcano‐sedimentary piles and younger plutonic intrusions, and yields chalcocite (‐digenite) and bornite as the principal hypogene copper sulfides. The latter is hosted mostly in Lower Cretaceous volcano‐sedimentary sequences, and has chalcopyrite‐rich mineral associations. The fluid inclusion data indicate that the primary copper mineralization was commonly generated in the temperature range 150–360°C under low‐pressure conditions near the boiling curve, mediated with relatively saline brines. Generally, homogeneous Pb and S isotope compositions for primary copper minerals imply direct magma source or leaching of igneous rocks. Pb and Os isotope data published for some deposits, however, suggest that ore‐forming metals were derived mainly from the volcano‐sedimentary host rocks. The noticeably negative isotope ratios of primary sulfide sulfur and hydrothermal calcite carbon of some central area deposits indicate influx of sedimentary rock components, and the high ⁸⁷Sr/⁸⁶Sr initial ratios of hydrothermal calcite from the Tocopilla–Taltal area deposits imply contribution of the contemporaneous seawater or marine carbonates. These isotopic constraints imply a formation mechanism in which the Chilean manto‐type copper deposits formed epigenetically in the process of hydrothermal interaction of non‐magmatic surface‐derived brine with the volcano‐sedimentary host rocks, which is inferred to have been induced by a deep‐seated plutonic complex as the possible heat source.     

化学侵蚀下硬脆性灰岩变形和强度特性的试验研究

 通过硬脆性灰岩在不同pH值、0.1 mol/L和Na2SO4和CaCl2溶液以及蒸馏水浸泡后的的常规三轴压缩试验,分析了受化学腐蚀作用的灰岩在不同围压下的变形及强度特性,探讨了三轴强度参数及变形参数的变化规律,并对浸泡岩石的化学溶液进行水质检测,得到了化学溶液中各离子浓度的变化规律,初步分析了化学溶液对灰岩力学特性影响的机制和规律。试验表明：化学溶液浸泡后,灰岩有从脆性向延性转化的趋势;灰岩的强度参数 , 值及弹性模量E均有不同程度的下降,而泊松比则增大;在相同的化学溶液侵蚀下,弹性模量和凝聚力降低幅度最大;灰岩力学参数劣化的程度与从灰岩中溶出的离子浓度的大小具有一定的对应关系：从灰岩中溶出的离子浓度越高,其力学参数劣化程度越大。     

Net Primary Productivity Increased on the Loess Plateau Following Implementation of the Grain to Green Program

The spatio-temporal characteristics of net primary productivity (NPP) since implementation of the Grain to Green Program (GTGP) are important for understanding ecological restoration of the Loess Plateau in China. Here, we conduct spatio-temporal analysis of NPP using MODIS datasets (500 m, 8-day intervals) and VPM (Vegetation Photosynthesis Model) from 2000-2015. We found that NPP on the Loess Plateau increased significantly from 2000 to 2015 (p<0.05). Significant increases in NPP were observed in core areas of the GTGP, including northern Shaanxi and Lüliang Mountain in Shanxi. NPP in alluvial plains decreased due to urban expansion into cropland. Significant increases in NPP from 2006-2010 were located north of the area of change in 2000-2005. NPP increased across three vegetation types and four slope gradients. In hilly-gully regions prone to soil erosion, such as central and southeastern parts of the Loess Plateau, obvious vegetation restoration was detected.     

黑河流域植被水分利用效率时空变化特征及其与气候因子的关系

利用中分辨率成像光谱仪（MODIS）产品总初级生产力（GPP）、蒸散发（ET）及气象数据估算了黑河流域植被水分利用效率（WUE）,分析了WUE的时空变化及与气候因子的相关性。结果表明：2005-2014年黑河流域单位面积上多年平均GPP为314.44 gC·m^-2,ET为363.35 mm,多年平均植被WUE为1.15 gC·mm^-1H₂O·m^-2;黑河流域WUE总体呈由南向北递增的空间分布格局,年内呈现单峰型结构,WUE高值区分布在酒泉-临泽东西线上及额济纳斯荒漠河岸林地带,托勒的东南部地区为WUE低值区;黑河流域生态系统WUE具有明显的季节变化规律,表现为夏季 > 春季 > 秋季 > 冬季的特征,夏季为1.32 gC·mm^-1H₂O·m^-2,冬季为0.75 gC·mm^-1H₂O·m^-2;水分利用效率年均分布与倾向率的增加具有一定的对应关系,莺落峡、民乐一带是WUE的高值区也是整个流域倾向率快速增长区,在WUE稳定性方面,中下游绿洲区变化最为显著,上游高海拔区、中下游戈壁区变化不显著;WUE与年降水量、年平均气温以负相关为主,其中降水是影响植被WUE的主要因素,正相关的区域分布在山丹县、民乐县东部、肃南裕固族自治县南部湖泊区域,而气温只在下游绿洲区呈正相关。     

Major Element Chemical Heterogeneity in Geo2 Olivine Microbeam Reference Material: A Spatial Approach to Quantifying Heterogeneity in Primary Reference Materials

A 270 spot‐analysis study was conducted across a large (ca. 1200 μm × 1200 μm) chip of Geo2 olivine from a commercially available GEO Mk2 block (P and H Developments 2016 , Standards for EPMA), which revealed an 8.7% relative range in FeO abundance. Interleaved and overlapping grids of different resolutions were measured sequentially to prove spatial patterns are not due to drift or other external sources of error. Results were mapped and interpolated using commercially available geographical information system software, such that composition could be predicted according to location with high accuracy. The simple, systematic zonation pattern observed demonstrates that useful‐sized regions of acceptable homogeneity do exist for some elements. This knowledge allows a user to target individual regions of a characterised chip for use as distinct measurement standards. As analysis times decrease and data sets grow, this approach may maximise laboratory efficiency by characterising large chips and extending time between conventional block repolish and coating, particularly in those cases where the avoidance of prior beam damage is a key concern.     

Photosynthesis versus irradiance relationships in the Atlantic sector of the Southern Ocean

Eleven incubation experiments were conducted in the South Atlantic sector of the Southern Ocean to investigate the relationship between new production (ρNO^–₃), regenerated production (ρNH⁺₄), and total carbon production (ρC) as a function of varying light. The results show substantial variability in the photosynthesis–irradiance (P vs E) parameters, with phytoplankton communities at stations that were considered iron (Fe)-limited showing low maximum photosynthetic capacity (P^B_max) and low quantum efficiency of photosynthesis (α^B) for ρNO₃, but high P^B_max and α^B for ρNH₄, with consequently low export efficiency. Results at stations likely relieved of Fe stress (associated with shallow bathymetry and the marginal ice zone) showed the highest rates of P^B_max and α^B for ρNO₃ and ρC. To establish the key factors influencing the variability of the photosynthetic parameters, a principal components analysis was performed on P vs E parameters, using surface temperature, chlorophyll-a concentration, ambient nutrients, and an index for community size structure. Strong covariance between ambient nitrate (NO₃) and α^B for ρNO₃ suggests that Fe and possibly light co-limitation affects the ability of phytoplankton in the region to access the surplus NO₃ reservoir. However, the observed relationships between community structure and the P vs E parameters suggest superior performance by smaller-sized cells, in terms of resource acquisition and Fe limitation, as the probable driver of smaller-celled phytoplankton communities that have reduced photosynthetic efficiency and which require higher light intensities to saturate uptake. A noticeable absence in covariances between chlorophyll-a and α^B, between P^B_max and α^B, and between temperature and α^B may have important implications for primary-production models, although the absence of some expected relationships may be a consequence of the small dataset and low range of variability. However, significant relationships were observed between ambient NO₃ and α^B for ρNO₃, and between the light-saturation parameter E_k for ρNO₃ and the phytoplankton community’s size structure, which imply that Fe and light co-limitation drives access to the surplus NO₃ reservoir and that larger-celled communities are more efficient at fixing NO₃ in low light conditions. Although the mean P^B_max results for ρC were consistent with estimates of global production from satellite chlorophyll measurements, the range of variability was large. These results highlight the need for more-advanced primary-production models that take into account a diverse range of environmental and seasonal drivers of photosynthetic responses.