鲁中寒武系馒头组震积岩的发现及初步研究

近几年在鲁中不同地区发现馒头组石店段中均有震积岩产出。震积岩形成于干燥的潮坪泻湖环境，发育在下寒武统的上部。它们具有记录强地震事件的泄水构造（地震成因泥晶脉）、液化卷曲变形、阶梯状小断裂、层内错断和液化网状裂纹等层内构造的特征。本文通过地层综合对比，论证了不同地区震积岩的等时性。认为：鲁中早寒武世末有一个地震活跃期；地震序列属乔秀夫（1994，2001a)提出的碳酸盐岩振动液化地震序列的原地系统；震积岩分布范围是约在510Ma前，以古郯庐带为震中的强地震之7－11度烈度区。为区别于张增奇（1996）提出的鲁中新元古代石旺庄期地震事件层，将此地震成因地层名之为馒头期地震事件层。     

Reducing Drift and Bias of a Global Ocean Model by Frequency-Dependent Nudging

Frequency-dependent nudging is applied to a coarse resolution (nominal 1°) global ocean model to suppress its drift and bias, and the impact of the nudging on the skill of the model is assessed. The nudging is applied to temperature and salinity in frequency bands centred on 0 and 1 cycles per year. As expected, the nudging significantly reduces the biases in the long-term mean and annual cycle of temperature, salinity, and sea level. By comparing the simulated (i) sea surface temperature with operational analyses based on observations, (ii) vertical profiles of temperature and salinity with observations made by Argo floats, and (iii) sea level with altimeter observations, it is shown that the skill of the model in simulating variability about the annual cycle is also improved. The potential benefit of applying frequency-dependent nudging to the ocean component of a coupled atmosphere–ocean model is discussed.     

2-D与3-D横向各向同性介质中波慢度面研究

首先简述了2-D横向各向同性介质中的波慢度面方程及其似P波、似SV波与似SH波速度关系式;接着推导了3-D横向各向同性介质中波慢度面方程,导出了3-D条件下地震波速度随波动传播方向变化的关系式;计算并讨论了2-D与3-D横向各向同性介质中地震波波慢度面及地震波波速,并发现,似P波、似SV波及似SH波波慢度面一般为不规则椭圆或椭球;似P波、似SV波与似SH波速度不仅与θ、(?)有关,而且,似SV波与似SH波的传播速度不同。     

溧阳戴埠火山岩开放体系岩浆活动探讨

戴埠下火山岩系层序—岩相—成分演化之间关系研究表明,火山产物是从十个喷发中心经深部岩浆脉动式补充、快速分异、间歇式喷发所形成。第一和第二旋回之间具沉积间断,而且喷发中心迁移与新生岩浆补充相对应。在两个旋回内部,中性和酸性喷发产物都具宽的或较宽的成分范围和快速分异特点。中性溢流相之后,从中酸性火山屑碎流相至酸性溢流相或侵出相的喷发强度降低,是岩浆房萃取深度降低的结果。分离结晶和同化作用是岩浆演化的主要原因。     

Geochemistry, Geochronology, and Hf isotopic Composition of the Late Paleoproterozoic Lujiapuzi Formation, NE Yan-Liao Rift, Northern Liaoning

The metasedimentary Lujiapuzi Formation crops out along the northeastern margin of the North China Craton, close to the Yan-Liao Rift. The age and tectonic setting of the formation, and its relationship with the Yan-Liao Rift are currently unclear. Here we present detrital zircon U-Pb ages, and Hf isotopic and geochemical data for the Lujiapuzi Formation to constrain the timing of deposition, the provenance of the formation, and the regional stratigraphy relationship. Zircon U-Pb dating constrains the timing of deposition of the Lujiapuzi Formation to younger than 1780 Ma, and indicates that most grains were sourced from the Longgang Block and the Paleoproterozoic Liao-Ji Belt. Detailed field investigations and a correlation of the regional stratigraphy reveal that much of the Lujiapuzi Formation is equivalent to the Tuanshanzi Formation in the Yan-Liao Rift; the lower section may represent the earliest sediments deposited within the Fanhe Basin. Based on these results and the findings of previous studies, we suggest that the base of the Changcheng System has an age of 1.80 Ga. Zircon Hf isotopic data indicate that the main period of crustal growth along the northeastern margin of the North China Craton occurred at 3.2–2.5 Ga, with a peak at 2.9–2.7 Ga.     

Crust–upper mantle seismic velocity structure across Southeastern China

One in-line wide-angle seismic profile was conducted in 1990 in the course of the Southeastern China Continental Dynamics project aimed at the study of the contact between the Cathaysia block and the Yangtze block. This 380-km-long profile extended in NW–SE direction from Tunxi, Anhui Province, to Wenzhou, Zhejiang Province. Five in-line shots were fired and recorded at seismic stations with spacing of about 3 km along the recording line. We have used two-dimensional ray tracing to model P- and S-wave arrivals and provide constraints on the velocity structure of the upper crust, middle crust, lower crust, Moho discontinuity, and the top part of the lithospheric mantle. P-wave velocity, S-wave velocity and V_P/V_S ratio are mapped. The crust is 36-km thick on average, albeit it gradually thins from the northwest end to the southeast end (offshore) of the profile. The average crustal velocity is 6.26 km/s for P-waves but 3.6 km/s for S-waves. A relatively narrow low-velocity layer of about 4 km of thickness, with P- and S-wave velocities of 6.2 km/s and 3.5 km/s, respectively, marks the bottom of the middle crust at a depth of 23-km northwest and 17-km southeast. At the crust–mantle transition, the P- and S-wave velocity change quickly from 7.4 to 7.8 km/s (northwest) and 8.0 to 8.2 km/s (southeast) and from 3.9 to 4.2 km/s (northwest) and 3.9 to 4.5 km/s (southeast), respectively. This result implies a lateral contrast in the upper mantle velocity along the 140 km sampled by the profile approximately. The average V_P/V_S ratio ranges from 1.68–1.8 for the upper crust to 1.75 for the middle and 1.75–1.85 for lower crust. With the interpretation of the wide-angle seismic data, Jiangshan–Shaoxin fault is considered as the boundary between the Yangtze and the Cathaysia block.     

几种药物对泥螺Bullacta exarata卵群孵化的影响

本文报道在泥螺人工育苗过程中高锰酸钾、福尔马林、土霉素三种药物对泥螺卵群孵化的影响。结果表明，高锰酸钾、福尔马林、土霉素的浓度分别为０．２８×１０－６～０．９×１０－６、５×１０－６～９×１０－６和１×１０－６～２０×１０－６时，泥螺卵群孵化率明显高于对照组，且对胶质膜的溶解有促进作用。使用上述药物后，还可提高卵群孵化的同步性。药物浓度超过上述范围，则孵化率明显下降，直至使胚体死亡。本文就胶质膜的作用进行了简单讨论，还对这三种药物在实际生产中的应用作了分析     

海南岛南部海草资源分布现状调查分析

结合2008年和2014年的调查数据,对海南岛南部海草分布现状进行分析探讨。结果显示,海南岛南部海草种类有2科3亚科5属5种,即海神草Cymodocea rotunda、泰莱藻Thalassia hemprichii、海菖蒲Enhalus acoroides、喜盐草Halophila ovalis以及二药藻Enhalus acoroides,泰莱藻广泛分布;海草分布面积从2008年的1.64km2减少到2014年0.50km2,减少幅度较大区域为铁炉港和小东海;平均盖度从2008年35.67%下降到2014年26.40%;受人为活动及无人管理因素影响程度不同,海南岛南部不同海域海草平均密度及平均生物量各有不同,后海湾与鹿回头海草平均密度和平均生物量呈增长趋势,铁炉港、西瑁洲岛及小东海海草平均密度和平均生物量呈下降趋势。鉴于海南岛南部海草资源已出现退化,希望社会各界重视海草的保护,在海草资源丰富区域设海草保护区,在海草破坏严重区域加大政府科研扶持力度,对海草进行保护与修复。     

古新世—中新世以来青藏高原北缘隆升的特征——来自可可西里盆地的报告

关于青藏高原隆升的时间有45 Ma、32 Ma、14 Ma等见解,一直存在争议。本文以青藏高原腹地最大的红色盆地可可西里为例,从古新世—中新世时期的沉积、生物、火山岩的特征等诸多方面,阐述青藏高原显著开始隆升的时间、表现特点和作用,并认为中新世初期,青藏高原有一次强烈的降温事件;在物质组分上,以钙质粘土、埃达克（Adakitic）火山岩为主;生物上以寒冷、干旱标志的裸子植物为主的植硅体;中新世中期之后青藏高原全面抬升。     

Platinum-Group Element Geochemical Characteristics of the Picrites and High-Ti Basalts in the Binchuan Area,Yunnan Province

The Binchuan area of Yunnan is located in the western part of the Emeishan large igneous province in the western margin of the Yangtze Block.In the present study,the Wuguiqing profile in thickness of about 1440 m is mainly composed of high-Ti basalts,with minor picrites in the lower part and andesites,trachytes,and rhyolites in the upper part.The picrites have relatively higher platinum-group element（PGE） contents（ΣPGE=16.3-28.2 ppb）,with high Cu/Zr and Pd/Zr ratios,and low S contents（5.03-16.9 ppm）,indicating the parental magma is S-unsaturated and generated by high degree of partial melting of the Emeishan large igneous province（ELIP） mantle source.The slightly high Cu/Pd ratios（11 000-24 000） relative to that of the primitive mantle suggest that 0.007%sulfides have been retained in the mantle source.The PGE contents of the high-Ti basalts exhibit a wider range（ΣPGE=0.517-30.8 ppb）.The samples in the middle and upper parts are depleted in PGE and haveε_Nd（260 Ma） ratios ranging from -2.8 to -2.2,suggesting that crustal contamination of the parental magma during ascent triggered sulfur saturation and segregation of about 0.446%-0.554% sulfides,and the sulfide segregation process may also provide the ore-forming material for the magmatic Cu-Ni-PGE sulfide deposits close to the studied basalts.The samples in this area show Pt-Pd type primitive mantle-normalized PGE patterns,and the Pd/Ir ratios are higher than that of the primitive mantle（Pd/Ir=1）,indicating that the obvious differentiation between Ir-group platinum-group elements（IPGE） and Pd-group platinum-group elements（PPGE） are mainly controlled by olivine or chromites fractionation during magma evolution.The Pd/Pt ratios of most samples are higher than the average ratio of mantle（Pd/Pt=0.55）,showing that the differentiation happened between Pt and Pd.The differentiation in picrites may be relevant to Pt hosted in discrete refractory Pt-alloy phase in the mantle;whereas the differentiation in the high-Ti basalts is probably associated with the fractionation of Fe-Pt alloys,coprecipitating with Ir-Ru-Os alloys.Some high-Ti basalt samples exhibit negative Ru anomalies,possibly due to removal of laurite collected by the early crystallized chromites.