长江口-杭州湾及其邻近海域不同粒级沉积有机碳分布特征

通过对长江口、杭州湾、舟山海域及东海陆架4个海区表层沉积物样品的粒度敏感组分分析,发现东海陆架与长江口具有相似的三级组分物质组成,杭州湾与舟山海域具有相似的两级组分物质组成.综合4个区域粒级组分分布特征,采用湿分法将4个海域表层沉积物样品分成6个粒级:＜0.004 mm,0.004～0.025 mm,0.025～0.063 mm,0.063～0.125 mm,0.125～0.250 mm和＞0.250 mm,分别提取各级组分和全样进行有机碳及同位素测试.定量分析各级组分有机碳含量、来源及物质组分,除杭州湾海域粗粒级外,基本上＜0.004 mm的粘土组分有机碳含量最高;富集在杭州湾海域粗颗粒中的有机质主要来源于陆源植物碎屑.沉积物颗粒大小、物质组成类型是不同粒级有机质富集的主要控制因素.     

吉林南部太古代花岗岩Sm—Nd,Rb—Sr同位素年龄测定

吉林南部太古代花岗质岩石经同位素年龄测定，英云闪长质片麻岩类的Ｒｂ－Ｓｒ全岩等时年龄为２４１７±１２１Ｍａ，Ｓｍ－Ｎｄ全岩等时年龄为２４１６±１２７Ｍａ，模式年龄为２８４０Ｍａ；辉石花岗岩类的Ｒｂ－Ｓｒ全岩等时年龄为２３４６±２３２Ｍａ，Ｓｍ－Ｎｄ全岩等时年龄为２４４０±１５９Ｍａ，模式年龄为２７８０Ｍａ。反映这些岩石都是在太古宙晚期形成的，并且是在较短的时间间隔内完成的，其模式年龄与华北地台太古宙主体地壳的形成时代一致。     

Distribution of CO_2 in Soil Air Affected by Vegetation in the Shilin National Park

This paper studies the CO2 distribution of soil atmosphere in the Shilin National Park. The measurement sites were chosen according to different topographic features and different vegetations. Seven measurement sites on 3 cross sections were chosen to pass through 3 karstic depressions or on the slopes of depressions. All measurement results show soils with pH values lower than 7.0 (from 5.4 to 6.6). There are 2 cases for the pH values of soil in different topographic features: the pH values of 2 profiles on the ridges or upper slopes of depressions are lower than those in the depressions; and the pH values of 2 soil profiles on the slopes of depressions are higher than those in the depressions. Most samples show relatively low humidity and CO2 contents on the ridges or slopes of depressions compared with soil profiles in the depressions. High CO2 contents occur at depths from -40 to -80 cm and high and dense grassland shows high CO2 contents in the soil atmosphere. Grass roots may grow and are distribu     

海洋激光测深技术介绍

介绍了机载激光海洋测深技术的原理、特点 ;简述了系统的组成和主要技术指标 ;概述了其发展历程、关键技术 ;分析了该项技术的发展趋势 ;最后对该项技术的应用前景进行了展望     

延边“早海西期”棉田花岗岩和仲坪紫苏辉石闪长岩的单颗粒锆石U—Pb定年

延边花岗岩是中国东北巨型花岗岩省的一部分.传统观点认为,该区花岗岩主要形成于古生代.但高精度的单颗粒锆石U-Pb定年显示,曾被认为是早海西期的棉田岩体和仲坪岩体形成于中生代,其侵位年龄分别为189±1 Ma、1 29±2 Ma,而不是以前认为的晚古生代.这一年代学结果同时还显示,两岩体是两期岩浆活动的产物,而并不是传统观点所认为的同源岩浆演化的产物.结合从延边地区部分原加里东期花岗岩中获得的中生代年代数据,认为华北地台与北侧佳木斯地块一兴凯地块间拼合历史的传统模式需要进一步修正.     

太古宙花岗岩中的暗色包体

在华北陆台北缘太古宙花岗质岩石的成因研究中,对其中的暗色包体进行了较详细的矿物学和岩相学研究,从中获得了许多反映花岗质岩浆来源及其成岩演化过程的信息,从而为花岗岩的岩浆起源提供了证据。这些暗色岩包体按成因及来源可分为:深源火成岩包体,围岩包体及深熔同生包体。研究表明,深源火成岩包体是花岗岩的母岩浆(基性岩浆)的早期结晶分离相,有些包体可能代表岩浆源区—上地幔岩的岩块。而深熔同生包体和围岩包体则是在深熔岩浆的形成过程中母岩中难熔组分的聚集物和岩浆上侵过程中捕获围岩的产物。     

Quantitative estimates of collective geo-tagged human activities in response to typhoon Hato using location-aware big data

ABSTRACT

Location-aware big data from social media have been widely used to quantitatively characterize natural disasters and disaster-induced losses. It is not clear how human activities collectively respond to a disaster. In this study, we examined the collective human activities in response to Typhoon Hato at multi spatial scales using aggregated location request data. We proposed a Multilevel Abrupt Changes Detection (MACD) methodological framework to detect and characterize the abrupt changes in location requests in response to Typhoon Hato. Results show that, at the grid level, most anomaly grids were located within a radius of 53?km around the typhoon trajectory. At the city level, there are significant spatial difference in terms of the human activity recovery duration (230?h on average). At the subnational level, the absolute magnitude of abrupt location request changes is strongly correlated with the typhoon-induced economic losses and the population affected.     

吉林省中部红帘石硅质岩的特征及意义

吉林省中部磐石县境内烟筒山地区的红帘石硅质岩存在于古生代地层之中。地球化学研究发现，该硅质岩具有较低的SiO2(80%左右)和较高的Al2O3(10％左右)。微量元素中V的含量也较低，稀土元素中不出现明显的Ce负异常，表明其形成于与陆源物质关系密切的大陆边缘环境。岩石的强烈变形和无层序特点暗示该区的古生代地层可能大多为构造混杂岩，不具备传统的地层划分和对比意义。矿物温压计算结果显示，该硅质岩经历了约430℃、大于6．OGPa的中压相系变质作用。不存在其他高压变质作用矿物，可能反映了本区为兴蒙造山带中古亚洲洋最后闭合的地点所在，并推测其最后闭合的时间应在古生代末一中生代初期。     

Zircon U–Pb ages and tectonic implications of 'Early Paleozoic' granitoids at Yanbian, Jilin Province, northeast China

Abstract   The Yanbian area is located in the eastern part of the Central Asian Orogenic Belt (CAOB) of China and is characterized by widespread Phanerozoic granitic intrusions. It was previously thought that the Yanbian granitoids were mainly emplaced in the Early Paleozoic (so-called 'Caledonian' granitoids), extending east–west along the northern margin of the North China craton. However, few of them have been precisely dated; therefore, five typical 'Caledonian' granitic intrusions (the Huangniling, Dakai, Mengshan, Gaoling and Bailiping batholiths) were selected for U–Pb zircon isotopic study. New-age data show that emplacement of these granitoids extended from the Late Paleozoic to Late Mesozoic (285–116 Ma). This indicates that no 'Caledonian' granitic belt exists along the northern margin of the North China craton. The granitoids can be subdivided into four episodes based on our new data: Early Permian (285 ± 9 Ma), Early Triassic (249–245 Ma), Jurassic (192–168 Ma) and Cretaceous (119–116 Ma). The 285 ± 9 Ma tonalite was most likely related to subduction of the Paleo-Asian Oceanic Plate beneath the North China craton, followed by Triassic (249–245 Ma) syn-collisional monzogranites, representing the collision of the CAOB orogenic collage with the North China craton and final closure of the Paleo-Asian Ocean. The Jurassic granitoids resulted from subduction of the Paleo-Pacific plate and subsequent collision of the Jiamusi–Khanka Massif with the existing continent, assembled in the Triassic. The Early Cretaceous granitoids formed in an extensional setting along the eastern Asian continental margin.