Rock magnetic properties and palaeomagnetic results of sediments from a stone implement layer in the Bose Basin,Guangxi

Directional samples were taken to study rock magnetism and palaeomagnetic records from the Dong- sheng profile, which is 5 m thick and on the northwest edge of the Bose Basin. Mineralogy and rock magnetism of typical samples indicate that coarse granular titanomagnetite, and fine-grained hematite, superparamagnetic maghemite formed by pedogenesis are in the sediment, which has undergone many transformative processes during different stages of pedogenesis. Parallel samples were taken for thermal demagnetization (TH) (0 to 680℃) and alternating field (AF) demagnetization (0 to 80 mT) respectively. Experimental results of these two kinds of demagnetization illustrate that there are two or more magnetic components in the samples. Intensity of NRM decreases by almost 60% to 90% rapidly when the temperature ranges from 100℃ to 350℃, with a steady magnetic component. It is impossible to analyze the magnetic components at high temperature because those fluctuate widely when the temperature is higher than 400℃. Steady magnetic components from 100℃ to 350℃ indicate that the remanence was mainly carried by fine-grained hematite formed by pedogenesis, reflecting a change in the geomagnetic field while the magnetite was being oxidized into hematite by chemical weathering after deposition. The formative age of the sediments cannot be obtained by magnetic methods in this profile.     

Phase Equilibria Constraints on Relations of Ore-bearing Intrusionswith Flood Basalts in the Panxi Region, Southwestern China

There are two types of temporally and spatially associated intrusions within the Emeishan large igneous province (LIP); namely, small uitramafic subvolcanic sills that host magmatic Cu-Ni-Platinum Group Element (PGE)-bearing sulfide deposits and large mafic layered intrusions that host giant Ti-V magnetite deposits in the Panxi region. However, except for their coeval ages, the genetic relations between the ore-bearing intrusions and extrusive rocks are poorly understood. Phase equilibria analysis (Q-PI-OI-Opx-Cpx system) has been carried out to elucidate whether ore-bearing Panzhihua, Xinjie and Limahe intrusions are co-magmatic with the picrites and flood basalts (including high-Ti, low-Ti and alkali basalts), respectively. In this system, the parental magma can be classified as silica-undersaturated olivine basalt and silica-saturated tholeiite. The equivalents of the parental magma of the Xinjie and Limahe peridotites and picrites and iow-Ti basalts are silica-undersaturated, whereas the Limahe gabbro-diorites and high-Ti basalts are silica-saturated. In contrast, the Panzhihua intrusion appears to be alkali character. Phase equilibria relations clearly show that the magmas that formed the Panzhihua intrusion and high-Ti basalts cannot be co-magmatic as there is no way to derive one liquid from another by fractional crystallization. On the other hand, the Panzhihua intrusion appears to be related to Permian alkali intrusions in the region, but does not appear to be related to the alkali basalts recognized in the Longzhoushan lava stratigraphy. Comparably, the Limabe intrusion appears to be a genetic relation to the picrites, whereas the Xinjie intrusion may be genetically related to be low-Ti basaits. Additionally, the gabbro-diorites and peridotites of the Limahe intrusion are not co-magmatic, and the former appears to be derived liquid from high-Ti basalts.     

An Improved Approach for Parameterizing Surface-Layer Turbulent Transfer Coefficients in Numerical Models

Based on classic iterative computation results, new equations to calculate the surface turbulent transfer coefficients are proposed, which allow for large ratios of the momentum and heat roughness lengths. Compared to the Launiainen scheme, our proposed scheme generates results closer to classical iterative computations. Under unstable stratification, the relative error in the Launiainen scheme increases linearly with increasing instability, even exceeding 15%, while the relative error of the present scheme is always less than 8.5%. Under stable stratification, the Launiainen scheme uses two equations, one for 0 < Ri _B ≤ 0.08 and another for 0.08 < Ri _B ≤ 0.2, and does not consider the condition that Ri _B > 0.2, while its relative errors in the region 0 < Ri _B ≤ 0.2 exceed 31 and 24% for momentum and heat transfer coefficients, respectively. In contrast, the present scheme uses only one equation for 0 < Ri _B ≤ 0.2 and another equation for Ri _B > 0.2, and the relative error of the present scheme is always less than 14%.     

Mid-Late Neoproterozoic rift-related volcanic rocks in China: Geological records of rifting and break-up of Rodinia

Early Cambrian and Mid-Late Neoproterozoic volcanic rocks in China are widespread on several Precambrian continental blocks,which had aggregated to form part of the Rodinia supercontinent by ca.900 Ma....     

Magma underplating and Hannuoba present crust-mantle transitional zone composition: Xenolith petrological and geochemical evidence

Studies on the deep-seated xenoliths from global volcanoes reveal that the present petrological crust-mantle boundary between the lower crust and the upper mantle actually is a transitional layer from mainly mafic granulites to ultramafic spinel lher-zolites[1,2], i.e. a transitional zone distinctive from the seismological Moho[3]. Oceanic lithosphere crust- mantle transitional zone can be established from the study on the exposed ophiolites. However, as for the continental lithosphere, since …     

Microbial Diversity in Nankai Trough Sediments at a Depth of 3,843 m

Dense populations of bivalves, primarily Calyptogena sp., were observed at cold seeps of the Nankai Trough. Bacterial input to the sediment was estimated through determination of phospholipid ester-linked fatty acid (PLFA) and DNA profiles. Results indicated a bacterial biomass of 10⁹ cells (g dry wt)^-1 while individual fatty acid profiles revealed a predominance of monounsaturated fatty acids, mainly 18:1 isomers. The presence of these fatty acids can be interpreted to reflect a response to low temperature and a predominance of psychrophilic bacteria. DNA fragments encoding bacterial ribosomal RNA small-subunit sequences (16S rDNA) were amplified by the polymerase chain reaction method using DNA extracted directly from the sediment samples. From the sequencing results, at least 19 kinds of bacterial 16S rDNAs related to mostly the Proteobacteria and a few gram-positive bacteria were identified. These results suggest that the bacterial community in the Nankai Trough sediments consists of mainly bacteria belonging to the Proteobacteria , , and subdivisions. Bacteria belonging to the and subdivisions, which are known to include epibiont and sulfate reducing bacteria, respectively, were mostly detected in the sediment obtained from inside the area of the Calyptogena community, and the -Proteobacteria may function to supply reduced sulfur to bacterial endosymbionts of Calyptogena.     

基于SilverLight和REST的富网络地理信息系统框架设计

 在WebGIS的快速发展过程中,其架构方法和实现技术的研究一直是人们关注的热点。本文针对传统WebGIS开发复杂度高、交互体验性贫乏、运行效率低等不足,在对RIA/SilverLight和REST技术的研究基础上,以整体结构模块化,开发行为统一化,代码可复用及经验可复用的指导思路下,提出由空间数据服务器(数据访问层DAL)、GIS服务和Web服务服务器(业务逻辑层BLL)及部署有SilverLight插件的浏览器(表现层UI)组成的3层架构式富网络地理信息系统,并阐述了数据层中空间属性数据库的设计和建立步骤以及优化经验,分析了业务逻辑层的构成和运行机制,为提高系统开发效率使用MVVM(Model-View-View Model,模型－视图－视图模型)设计模式,将表现层分为前端用户界面和后台逻辑两部分,并描述了用户熟悉的Office Ribbon设计样式的开发方法,说明了后台逻辑架构组件各自功能及通讯路径。最后,为验证此框架能够有效提高系统开发效率、丰富用户体验和改善系统运行性能表现等优势,利用SilverLight(C#)实现了应用实例——LightGIS。系统开发和运行实验表明,该框架能够很好地达成以下目的:(1)实现优美的用户操作界面和丰富的互操作性体验;(2)提供平滑、流畅的地图服务和高响应性空间分析;(3)具备优秀的系统可扩展潜力和可配置性。     

Interannual and interdecadal variations of the South Asian and western Pacific subtropical highs and their relationships with Asian-Pacific summer climate

In this study, interdecadal and interannual variations of the South Asian high (SAH) and the western Pacific subtropical high (WPSH), as well as their relationships with the summer climate over Asian and Pacific regions, are addressed. The variations of SAH and WPSH are objectively measured by the first singular value decomposition (SVD) mode of geopotential heights at the 100- and 500-hPa levels. The first SVD mode of summertime 100- and 500-hPa geopotential heights represents well the relationship between the variations of SAH and WPSH. Both SAH and WPSH exhibit large interannual variability and experienced an apparent long-term change in 1987. The WPSH intensifies and extends westward when SAH intensifies and extends eastward, and vice versa. The India?CBurma trough weakens when WPSH intensifies. The changes in SAH and WPSH at various levels are linked to broad-scale increases in tropical tropospheric temperature and geopotential height. When SAH and WPSH strengthen, monsoon flow becomes weaker over eastern Asia. In the meantime, precipitation decreases over eastern South China Sea, Philippines, the Philippine Sea and northeastern Asia, but increases over China, Korea, Japan and the ocean domain east of Japan. Similar features are mostly found on both interdecadal and interannual timescales, but are more evident on interannual timescale.     

济南北部地热田地热地质特征浅析

济南北部地热田地热资源类型属于层状裂隙岩溶型,热源是北部齐河-广饶断裂的沟通导热,盖层是第四系、新近系、石炭-二叠系、侏罗系.可利用的、具有开发价值的热储层为奥陶系灰岩热储,该热储层顶板埋深在700～2500m左右,热储层厚度由南向北逐渐增大,单井涌水量2000m3/d左右,孔口水温一般在38～57℃,地热田东部地热水矿化度1.4～3.5g/L左右,西部5.1～7.2g/L左右,地热水中富含氟、锶、偏硅酸等微量元素,具腐蚀性,结垢性弱,具较好的开发利用价值.经计算奥陶系热储层单井可采资源量为7.3×105m3/a,合理井间距为5000m.     

南秦岭金龙山微细浸染型金矿成矿时代

 金龙山金矿带是南秦岭新发现的卡林型金矿带,主要产于上泥盆统南羊山组细碎屑岩—碳酸盐岩建造中,在上泥盆统冷水河组、下石炭统碳酸盐建造中也有产出,可分为明显受断裂控制的脉型金矿化和受有利岩性及小规模断裂、节理控制的浸染型矿化。