Carbon isotopes and lignin phenols for tracing the floods during the past 70 years in the middle reach of the Changjiang River

The Lake Tian E Zhou(TEZ,an oxbow lake)was formed during the rerouting of the Changjiang River in 1972,with strong influences from the main river channel and flood events.Herein,a sediment core was collected from the Lake TEZ for the measurements of carbon isotopes and biomarkers,including stable carbon isotopes(δ13C),radiocarbon composition(?14C),and lignin phenols,as well as lead-210 to reconstruct recent heavy flood events over the past 70 years.At the 24–26 cm interval,the sediment contained the highest OC%,TN%,and lignin phenols content,as well as significantly depleted 13C but enriched 14C,corresponding to the extreme flood event in 1998.In addition,statistics from t-test showed that lignin phenols normalized to OC(Λ8),the concentration of 3,5-dihydroxy benzoic acid(3,5-BD),and the ratio of p-hydroxy benzophenone to total hydroxyl phenols(PHB/HP)were all significantly different between the layers containing flood deposits and the layers deposited under normal non-flood conditions(p<0.05).These results indicate that the later three parameters are highly related to flood events and can be used as compelling proxies,along with sediment chronology,for hydrological changes and storm/flood events in the river basin and coastal marine environments.     

深远海海域多波束水深测量声速剖面获取方法研究

声速是影响多波束勘测精度的重要的外部因素,它决定着声线跟踪的精度,并最终影响到测深精度。由于停船投放CTD时间成本比较高,探索经济高效的远海走航式多波束水深测量,特别是航渡测量期间的声速剖面获取方法成为现场测量人员急需解决的问题。在对HYCOM/WOA13数据与现场CTD数据进行了数据偏差分布、相关性等比对,验证HYCOM/WOA13数据适用性的基础上,提出了基于HYCOM模式数据、WOA13同化数据及单点历史CTD数据与现场XCTD/XBT多源组合的远海走航式多波束水深测量声速剖面获取方法。对比表明,该多源组合的声速剖面能较好反映施测位置的声速剖面情况,该方法对提高远海水深测量的精度和经济效益具有一定的借鉴意义。     

Analysis and prediction of influence imposed on Jiaozhou Bay tidal currents and tidal energy of M2 tidal system by Jiaozhou Bay reclamation

The 3-D ECOMSED ocean model was applied to establish a time-dependent boundary model for Jiaozhou Bay (JZB), in which the operator-splitting technique was used and the ‘dry and wet’ method was introduced. The influence caused by JZB reclamation on the surface level, residual currents, tidal system and tidal energy of M₂ tidal system were predicted and analyzed. The results show that JZB reclamation has slight impact on the M₂ tidal system, in which the variation of amplitude and phase is less than 1%.The changes of the currents and residual currents in Qian Bay and near the reclamation areas are greater, but in other areas the changes are smaller, in which the currents have a change of around 1%, while the residual currents change ranges from 1.82%–9.61%. After reclamation, the tidal energy fluxes increase by 2.62%–5.24% inside and outside the JZB mouth, but decrease by 20.21%–87.23% near Qian Bay and the reclamation area.     

汶上县节约集约用地破解用地难题

汶上县辖区面积887km^2,耕地面积5．6万hm^2,全县人口72万人,其中农业人口64万人,人均耕地仅为0．073hm^2（1．1亩）,土地后备资源十分缺乏。近年来,随着汶上县工业化、城镇化的快速发展,土地供需矛盾日益凸显,为此,汶上县立足实际、不断更新用地观念,加强土地宏观调控,强力推进了粗放型向节约集约型用地模式的转变。通过加大土地整理力度、盘活存量建设用地、严把闸门等举措,有效破解了用地难题。     

山东莱芜黄羊山晚寒武世牙形石组合及寒武系与奥陶系界线的确定

通过实测莱芜黄羊山晚寒武世地层剖面,利用牙形石确定了寒武系与奥陶系的界线;对长山阶的碳氧同位素曲线特征进行了分析,并与我国华南及哈萨克斯坦等国的寒武系芙蓉统底部的碳同位素曲线进行对比,建立了莱芜地区上寒武统与华南以及国外上寒武统的对比关系。     

Microphytobenthic biomass and species composition in intertidal flats of the Nakdong River estuary, Korea

Intertidal microphytobenthos (MPB) were investigated monthly from August 2006 to March 2008 at four different sites in the sand flats of Nakdong River estuary, Korea. Samples of surface sediment (ca. 1 cm) were collected, and chlorophyll a was extracted as biomass estimation. Species identification and enumeration were carried out by light microscopy, assisted where necessary by scanning electronic microscopy. Biomass varied between 0.47 and 16.58 μg cm⁻³, abundance changed from 5.25 to 414.75 × 10³ cells cm⁻³, while the Shannon diversity indexes ranged between 0.69 and 2.35 H′. Thirty-nine MPB taxa were identified, primarily composed of epipelic diatoms, among which Amphora and Navicula were the most abundant genera. Based on the biomass, abundance, species composition and their dynamics, MPB assemblages of sampling sites were grouped into three distinct communities corresponding to their sediment composition characteristics. Multivariate correlation analysis revealed that biomass was positively related to mud and very fine sand, negatively related to fine and medium sand, but not significantly related to environmental factors such as pore water nutrients, light intensity and salinity, which fluctuated rapidly during emersion period. Cluster analysis corroborated the division of MPB communities according to site types on seasonal scales, and also showed seasonality between sites by cluster of all summer groups. Principal component analysis identified that variability in species composition was significantly affected by mud, very fine sand, fine sand, light intensity, and sediment temperature. This study suggests that sediment composition plays an important role in the functioning of intertidal MPB communities in estuarine ecosystems.     

大别山榴辉岩的单矿物中He、Ar同位素特征

文中分析了大别榴辉岩的3对单矿物中的He、Ar质量分数及同位素组成。所有分析的矿物中，He主要是放射性成因的，而Ar主要是幔源的。He同位素特征更多地显示古洋壳的特征。He、Ar同位素体系表明其是放射性成因和富集地幔源混合的结果。     

云南哀牢山金矿带大坪金矿铂族元素(PGE)和Re-Os同位素地球化学及其矿床成因意义

采用镍硫火试金ICP-MS法和Carius管溶矿与ICP-MS联合测定法分析了云南大坪金矿各类金矿石和主要围岩的PGE和矿石矿物的Re-Os同位素组成,结果显示各类金矿石的ΣPGE变化较大,为(3.91~61.64)×10-9,平均25.93×10-9,与该区喜马拉雅期煌斑岩脉(22.19×10-9)相当,而高于加里东期闪长岩围岩((2.79~4.75)×10-9);金矿石Pt/Pt均低于1,为0.01~0.9,平均0.249,接近煌斑岩(0.45),而远低于闪长岩围岩的(1.38~1.57)。金矿石的球粒陨石标准化曲线显示明显的Pt和Ir负异常和Ru与Rh正异常,相似于煌斑岩脉的PGE配分模式,而明显区别于闪长岩围岩,显示大坪金矿成矿与幔源煌斑岩等基性岩脉的侵入有关,成矿物质主要不是来自闪长岩。PGE元素比值显示该区煌斑岩脉可能是由经历了基性岩浆抽提和交代作用形成的亏损地幔部分熔融产生的,其原始岩浆中S已达到饱和。大坪金矿矿石矿物的Re/Os比值均>1,为6.36~121.67,γOs(t)均为高正值,为290.21~810.24,平均492.92,187Os/188Os(t)为0.495~1.154,远高于金矿形成时(距今约33.55Ma)球粒陨石187Os/188Os的初始比值(0.12679),显示该矿成矿过程中有来自地壳的高放射性成因187Os的加入。PGE和Re-Os同位素组成显示大坪金矿的成因与该区新生代以来强烈的壳幔相互作用有关,其成矿流体主要来自地幔排气形成的深源地幔流体和下地壳脱水形成的富CO2流体,韧性剪切带提供了流体运移和汇聚的通道,深源流体与闪长岩之间的水/岩反应和沸腾作用导致物理化学条件的改变和矿质沉淀。大坪金矿属于典型的剪切带控制的深源热液型金矿。     

四川泸州地区测震台网地震监测能力研究

为加强川南泸州区域的地震监测能力,新建15个流动测震台站,与泸州和荣昌2个固定台站形成泸州台网.根据《地震震级的规定GB 17740-2017》,计算了泸州台网的震级监测能力,并通过实际地震事件的统计分析,验证了震级监测能力计算结果的准确性和合理性.基于D值理论,计算了泸州台网在研究区域的震中定位误差和震源深度定位误差...