High-resolution magnetostratigraphy and micropalaeontology across the J/K boundary strata at Brodno near ilina, western Slovakia: summary of results

This study summarizes the final results of magnetostratigraphic and micropalaeontological investigations of the Tithonian/Berriasian boundary (J/K) limestones at the locality of Brodno near ilina, Western Carpathians, West Slovakia. The aim is to prepare the background for correlation of a Late Tithonian and Early Berriasian biostratigraphic zonation with global magnetoevents (manifested in detailed magnetostratigraphic profiles) between the Tethyan realm and other regions, particularly the Boreal and Pacific realms. Suitable physical properties of the limestones studied, a favourable geological setting and rich microfossil assemblages (calpionellids) at Brodno (magnetozones M21r to M18r) allowed a systematic collection of new data on the original synoptic section, which now has the character of a high-resolution profile across the J/K boundary. Two reverse subzones detected within magnetozones M20n and M19n are named ‘Kysuca Subzone’ and ‘Brodno Subzone’, respectively. Both can be correlated with analogous subzones in the M-sequence of marine anomalies. Their existence can also be confirmed in the Bosso Valley section in Umbria, central Italy. A detailed study of the interval between magnetozones M20n and M17r in the Bosso Valley profile is presently in its final stage. Both magnetostratigraphic profiles, from the Brodno and Bosso Valley localities, were thoroughly investigated in the intervals close to the J/K boundary and are still unique among continent-based profiles in the detection and precise definition of both reverse subzones within M20n and M19n. Samples collected from the boundary strata of the reverse Kysuca Subzone at Brodno indicated a transition from N (R) to R (N) polarity of the Earth's palaeomagnetic field within a time interval of c. ±5 ka. Limestone samples (total number N=368) were subjected to progressive thermal demagnetization in 10–12 thermal fields and to subsequent multi-component analysis of remanence. The C-component, as the carrier of palaeomagnetic directions, was determined in the temperature interval of 300° to 540°, or possibly 580°C. Magnetomineralogical analyses of pilot samples and unblocking temperatures determined for all samples showed that magnetite is the carrier of remanent magnetization. The positions of the individual events of calpionellid stratigraphy relative to the global magnetic polarity timescale are precisely defined. The base of the Calpionella Standard Zone, which is considered a provisional J/K boundary indicator in ammonite-free sections in the Tethyan realm, lies within magnetozone M19n at the level of 35% of its local thickness. None of the boundaries in the calpionellid zonation coincides precisely with any of those in the palaeomagnetic zonation, but the first appearance ofCalpionella grandalpina , indicating the base of the Intermedia Subzone, lies in close proximity to the base of magnetozone M19r.     

The Acute Toxicity of Plant Origin Pesticides into the Freshwater Fish Channa punctatus

Mortality to fish Channa punctatus caused by the latices of four species of terrestrial plants belonging to family Euphorbiaceae and Apocynaceae have been reported. It was found that extremely dilute aqueous solutions of the latex were effective in killing the fishes. The ranking of toxicity of four plants was Nerium indicum > Euphorbia royleana > Thevetia peruviana > Jatropha gossypifolia. It has been suggested that these plant products cannot be used directly in freshwater ecosystem unless their detailed toxicity has been studied on the beneficial freshwater animals.     

Significance of an In Vivo Genotoxicity Test for Surface Waters Is Increased when the Physiological Characteristics of the Test Organism (Bivalvia: Mollusca) Are Taken into Account?

The alkaline filter elution assay using the gills of the freshwater clam species Corbicula fluminea detects breaks in single‐stranded DNA and is thus a good method for determining the genotoxic potential of surface waters. In attempting to standardize the procedure, a wide range of factors which could have an influence on the uptake of genotoxic substances by the exposed clams were studied. The most important parameters of the static exposure in relation to the rate of filtration by the animals turned out to be the temperature, the volume of the water, and the exposure time. Differences in body size and in the amount of suspended particles in surface waters did not play a significant role. The results demonstrate that the in vivo test system can be quite sensitive and its results reproducible when the relevant species‐specific characteristics of the test organisms are brought into consideration, even if the test organism belongs to a biologically more advanced group. A clear dose‐response relationship to the reference substances 4‐nitroquinoline‐1‐oxide (NQO) and N‐methyl‐N‐nitro‐N‐nitrosoguanidine (MNNG) can be observed even after a short exposure time of between four and twenty hours. No genotoxic effects were observed when using this method on surface waters from the area of Cologne (including water from the Rhine River and within the protection zone 2 of the Cologne waterworks).     

Study and application of an improved four-dimensional variational assimilation system based on the physical-space statistical analysis for the South China Sea

The four-dimensional variational assimilation (4D-Var) has been widely used in meteorological and oceanographic data assimilation. This method is usually implemented in the model space, known as primal approach (P4D-Var). Alternatively, physical space analysis system (4D-PSAS) is proposed to reduce the computation cost, in which the 4D-Var problem is solved in physical space (i.e., observation space). In this study, the conjugate gradient (CG) algorithm, implemented in the 4D-PSAS system is evaluated and it is found that the non-monotonic change of the gradient norm of 4D-PSAS cost function causes artificial oscillations of cost function in the iteration process. The reason of non-monotonic variation of gradient norm in 4D-PSAS is then analyzed. In order to overcome the non-monotonic variation of gradient norm, a new algorithm, Minimum Residual (MINRES) algorithm, is implemented in the process of assimilation iteration in this study. Our experimental results show that the improved 4D-PSAS with the MINRES algorithm guarantees the monotonic reduction of gradient norm of cost function, greatly improves the convergence properties of 4D-PSAS as well, and significantly restrains the numerical noises associated with the traditional 4D-PSAS system.     

南海北部神狐海域细粒储层矿物组分对天然气水合物储集赋存的影响

为了探明矿物类型对于天然气水合物成藏的影响,笔者等利用南海北部神狐海域W07站位样品及其水合物饱和度数据,进行XRD全岩和黏土矿物测试分析、比表面积分析以及束缚水能力综合分析。结果表明,海床下110~127 m（即110~127 mbsf,meters below sea floor, 海床以下深度）为水合物储层段,海床下127~156 m为非水合物储层段。通过XRD分析可知,高石英及长石含量,低伊蒙混层含量的层段,比表面积与束缚水能力较低,说明其具有相对较好的孔渗条件,为水合物的运移与储集提供了良好的空间条件,因此形成水合物储层段;而在高伊蒙混层的层段中,比表面积较大,束缚水能力较强,其对甲烷气体及流体的吸附和束缚能力较强,对水合物成藏起到潜在的封隔作用,成为非储层段,储层与非储层段纵向叠置序列有利于优质水合物储层的形成。本次研究总结了矿物组分与优质水合物储层之间的关系,并揭示两者存在的潜在成因联系,以期丰富水合物富集成藏的基础理论,对未来南海北部天然气水合物的商业化开发提供支持。     

FY-4A/LMI闪电与浙江三维闪电对比分析

为进一步加强星地闪电观测资料运用,本文基于2020年6—8月FY-4A/LMI闪电数据(LMIG)和浙江省ADTD-2C三维闪电定位数据,对比分析两套闪电数据的时空分布特征,并结合雷达和云顶亮温资料,分析了2020年7月15日浙江省雷暴过程两套闪电观测资料的演变规律。结果表明：2010年6—8月,浙江省LMIG与三维闪电比值为1∶44.43;两套资料闪电月分布和空间分布总体一致;就日分布而言,LMIG呈现双峰结构,三维闪电则为单峰结构。两套数据时间匹配窗口大于1.8 s、经纬度匹配窗口大于0.5°时,匹配率趋于稳定;与LMIG匹配的三维闪电高度主要集中在16 km以下,闪电强度主要集中在50 kA以下。2020年7月15日浙江省午后雷暴天气,LMIG与三维闪电比值为1∶25.44;LMIG首次闪电及峰值时间均滞后于三维闪电首次闪电及峰值时间;此外两套闪电资料时间演变与雷暴发展有较好的对应,空间变化与云顶亮温低值区也有较好的对应。     

哈萨克斯坦卡帕尔-阿拉善4号井前兆异常特征分析

选取距卡帕尔-阿拉善4号井300 km范围内的3次5级地震,400 km内的3次6级地震,约600 km内1次7级地震、1次6级强震群作为震例资料,分析了这些地震前卡帕尔-阿拉善4号井前兆异常特征。结果表明:①对于5级地震,50.0%测项出现前兆异常,水化学、水动态异常各占50.0%。这些异常的58.3%表现为中期异常,41.7%表现为短期异常,无单独临震异常,也无叠加临震异常。异常变化幅度大而明显,且以趋势性上升或下降为主。硅酸和硫酸根在同一地震前异常时间与异常形态相似。②对于6级地震,33.3%测项出现前兆异常,其中水化学异常占38.9%,水动态异常占16.7%。出现的异常57.1%为中期异常,28.6%为短期异常,14.3%为临震异常。异常形态多为脉冲突跳,而仅有少数为趋势性高值异常。各异常项目之间有一定的同步性。③对于7级地震或6级强震群,37.5%测项出现前兆异常。出现的异常83.3%为中期异常,16.7%为短期异常。异常幅度大而明显,异常形态以单值突跳或趋势性为主。     

泥炭记录的帕米尔高原晚全新世温度变化研究

近年来,“全新世温度谜题”已经受到全球古气候学者的广泛关注,为了解决这一谜题,需要在全球不同区域进行更多的全新世温度重建。帕米尔高原位于亚洲内陆核心区域,目前有关帕米尔高原全新世气候变化的研究相对较少,且已有的研究主要集中于相对湿度(或降水)变化的研究,而涉及温度变化的成果则相对较少。论文首先研究了表土碳同位素与气候因子之间的相关关系,结果显示帕米尔高原的δ¹³C_org与温度正相关;进一步在 7 个AMS¹⁴C 测年数据的支持之下,基于 175 个泥炭δ¹³C_α-cellulose分析,重建了帕米尔高原过去约5000 a的温度变化历史。结果发现：帕米尔高原晚全新世以来整体呈现波动升温趋势,约5000～3600 cal a BP阶段处于缓慢降温期;约3600～200 cal a BP 处于波动升温期;驱动机制分析显示,约 3600 cal a BP 之前温度下降主要是夏季太阳辐射下降导致的,约3600 cal a BP之后温度上升是由温室气体辐射强迫增强导致的。     

安徽铜陵冬瓜山铜矿床成矿流体特征及演化

对安徽铜陵冬瓜山矿床内矽卡岩矿物、石英、方解石中的流体包裹体进行了岩相学和显微测温分析、群体包裹体气液相成分分析、单个包裹体气液相成分激光拉曼探针分析,探讨了成矿流体的特征及演化。研究表明,该矿床与燕山期岩浆热液有关的成矿流体,从早期矽卡岩阶段,经中期石英硫化物阶段,至晚期石英方解石阶段,是从高温、高盐度、富钾流体演化至中高温、中高盐度、富CO2(CH4)流体再至中低温、低盐度流体。成矿流体中的主要挥发分为H2O、CO2、CH4,并含少量C2H6、H2S、N2等,液相成分中的阳离子以Na 、K 为主,有少量Ca2 、Mg2 等,阴离子除Cl-外,SO42-的含量也较高。     

Assessment of FY-4A and Himawari-8 Cloud Top Height Retrievalthrough Comparison with Ground-Based MillimeterRadar at Sites in Tibet and Beijing

正1Key Laboratory of Middle Atmosphere and Global Environment Observation, Institute of Atmospheric Physics,Chinese Academy of Sciences, Beijing 100029, China2University of Chinese Academy of Sciences, Beijing 100049, China