中国近海沿岸泥的地球化学特征及其指示意义

中国海域辽阔，分为渤海、黄海、东海和南海4个海区。各海区沿中国大陆均有呈斑块状或条带状的泥质沉积分布。选取各沿岸泥的代表性样品，采用先进的XRF和ICP－MS等方法，测定了K、Li、Rb、Cs、Mg、Ca、Sr、Ba、Al、Fe、Ti、Be、Nb、Ta、W、Sn、Bi、La、Ce、Th。元素的地球化学研究表明：渤海和黄海、东海、南海沿岸泥的地球化学特征分别与黄河、长江、珠江沉积物的地球化学特征一致，显示了元素的物源效应；从渤海到南海，由于气候的变化使沿岸泥中某些元素有所流失或富集，显示了元素的气候效应；中国沿岸泥元素的丰度相对接近中国大陆沉积物的丰度，而异于西太平洋褐色粘土和深海粘土的丰度，显示了元素的亲陆性。     

中国东部海域地质特征及一些重要大地构造界线在海区延伸的地质地球物理证据

本文通过对中国东部海域地质地球物理资料进行综合分析,特别是近十年来海洋区域地质调查最新采集的地球物理资料,梳理了研究区基础地质特征,探讨了陆区大地构造单元在海区的延伸。研究表明:渤海和北黄海为典型的华北型基底并发育华北型沉积盖层;南黄海为典型的扬子型基底并发育扬子型沉积盖层;东海陆架为华夏型基底,东部很可能发育晚古生代沉积盖层,其上叠置了晚三叠世以来沉积盖层。下扬子地块西侧通过左旋走滑的郯庐断裂带,东侧通过右旋走滑的朝鲜西缘断裂带揳入华北地块中,朝鲜西缘断裂带兼具走滑和俯冲带性质。整个朝鲜半岛无论从变质基底和沉积盖层来看都类似于华北地块。扬子地块在北侧和东侧都发育“鳄鱼嘴”式构造,扬子地块的下地壳向北、向东俯冲于华北地块之下,而上地壳则仰冲于华北地块之上。江绍结合带表现为宽50~70 km的NE向高磁异常条带,进入杭州湾后走向转为近EW向,经舟山群岛、大衢山岛及附近岛屿,过东海陆架虎皮礁凸起向东进入日本九州岛。虎皮礁凸起的岩石很可能类似于大衢山岛,为一套俯冲增生杂岩。     

我国沙尘的来源、移动路径及对东部海域的影响

利用中国气象局提供的micaps天气资料,通过对2000—2002年发生的42次沙尘天气个例的分析,重点研究了沙尘的源地、移动路径、入海地点及对不同海域的影响概率。结果表明：影响我国的沙尘天气有70%起源于蒙古国,在经过境内沙漠地区时得以加强。沙尘粒子的移动和入海途径主要有3条：一是从内蒙古东部入侵的沙尘天气经浑善达克和科尔沁沙地后进入渤海和黄海;二是从内蒙古西部入侵的沙尘天气经内蒙古西部沙地和黄土高原后进入渤海、黄海和东海;三是从青海东部扬起的沙尘长距离输运进入黄海、东海及西北太平洋。2000—2002年,63.9％的沙尘天气会影响到海洋,其中,影响渤海、黄海和东海的概率分别为27.4％、30.9％和12.3％,影响朝鲜海峡和日本海的概率为20.2％和9.2％。     

中国近海潮汐变化对外海海平面上升的响应

针对外海海平面上升对中国沿海潮波系统和潮汐水位可能带来的影响,通过西北太平洋潮波数学模型对边界海平面上升后潮波变化进行了数值模拟。研究发现边界海平面上升后,在无潮点附近东侧迟角增加,西侧迟角减小;无潮点北侧振幅增加,南侧振幅减小;辽东湾、渤海湾顶、辽东半岛东海域、海州湾至鲁南沿海、苏北沿海、台湾海峡至浙东沿海和南海平均潮差增加,海平面上升0.90 m后潮差最大增幅达0.40 m;长江口、杭州湾至对马海峡、朝鲜西海岸和莱州湾海域潮差减小。随着海平面上升量值的增加,渤海、台湾海峡潮差变化速率相对稳定,黄海、东海和南海站位变化速率有所变动;平均高水位的变化趋势与潮差一致;潮差增加的区域,高水位抬升幅度超过边界海平面上升幅度。海平面上升引起的高水位超幅变化,增加了沿海地区对风暴潮和其他灾害防护的风险。     

Microplastic pollution in Yellow River,China: Current status and research progress of biotoxicological effects

This study aims to comprehensively assess the environmental risks of microplastics in the Yellow River, achieving the following results through comprehensive research. The average microplastic abundances in the river waters and sediments are 5358–654000 n/m³ and 43.57–615 items/kg, respectively, and there are fewer microplastics in water samples than in sediments. Microplastics in the study area can be divided into five types according to their occurrence morphologies, namely fragments, foams, films, fibers, and particles. The most widely distributed pollution types in sediments include debris, fibers, and particles. In contrast, fibers are the dominant type in water samples, accounting for 68.18% –98.93%. The chemical components of the microplastics include polyethylene, polypropylene, polystyrene, polyethylene terephthalate, and polyvinyl chloride. The microplastics are in four colors, with white accounting for a higher proportion. The grain size of the microplastics in tributaries or lakes of the Yellow River is less than 2 mm, which makes them liable to enter organisms for enrichment. Furthermore, the sources of the microplastics are closely related to agricultural and industrial production and biological activities in habitats and exhibit seasonal and hydrological characteristics. The microplastics in the study area show the adsorption of metals and nonmetals to different degrees, which increases the pollution risks of heavy metals combined with microplastics. In addition, microplastics can accumulate in organisms in the Yellow River and cause physical, biochemical, and other damage to aquatic organisms, thus further posing carcinogenic risks to human beings. Therefore, it is necessary to study, monitor, and control the pollution and effects of microplastics in the Yellow River, in order to provide theoretical references for the control of pollution and ecological risk of microplastics in the river.©2021 China Geology Editorial Office.     

Distribution,characteristics, and research status of microplastics in the trunk stream and main lakes of the Yangtze River: A review

Microplastic pollution has become an environmental issue of great concern owing to the persistence of microplastics and their potential adverse effects on biota.The Yangtze River is the longest river in China and the third-longest river in the world,and the microplastics in this river will affect the health of a large population living along with it.To ensure the survival safety of people,it is essential to plan ahead and investigate in advance in order to understand the microplastic pollution in the river and work out countermeasures.This paper reviews the literature concerning the microplastic pollution in the Yangtze River basin and analyzes the abundance,shapes,colors,and composition of microplastics in the water bodies and sediments in the trunk stream and main lakes of the Yangtze River.The results are as follows.Compared to other river basins in China and abroad,the microplastics in the Yangtze River basin have a moderate abundance and high spatial heterogeneity.Owing to the barrier effect of the Three Gorges Dam on microplastics,the abundance of microplastics in the Three Gorges Reservoir is generally an order of magnitude higher than that in other sections of the river.Most microplastics in the water bodies and sediments are less than 1 mm in size and are transparent and colorful.In terms of shapes,they are dominated by fibers,followed by fragments and films.In terms of composition,the microplastics in the source region of the Yangtze River are mainly composed of nylon and polyethylene,while the microplastics in the surface water from the lower reaches of the Jinsha River to the Yangtze River estuary are dominated by polypropylene and polyethylene.The microplastics are primarily derived from the secondary microplastics in the environment,and relatively intensive human activities increase the abundance of microplastics.These results serve as bases for understanding and preventing microplastic pollution in the Yangtze River.     

黄东海陆架及朝鲜海峡泥质沉积物的磁学特征比较研究

黄东海陆架和朝鲜海峡等5个泥质沉积区全新世中期以来(自约6kaB.P.至今)的细粒沉积物主要是黄河、长江和朝鲜半岛的河流入海物质在复杂的海洋动力系统中的沉积产物.对取自山东半岛北部近岸泥质区和长江口以南的闽浙沿岸泥质区(舟山群岛近岸海区)的表层细粒沉积物(粘土质粉砂和粉砂质粘土)开展了详细的岩石磁学测试,包括磁化率、等温剩磁和样品磁化率随温度的变化等分析,并将实验数据与以往研究过的济州岛西南陆架区、南黄海东南部陆架区和朝鲜海峡西岸等3个泥质沉积区细粒沉积物的磁学特征进行比较研究.结果表明,上述5处细粒沉积物的磁性矿物主要组分为磁铁矿、磁赤铁矿和赤铁矿,其中低矫顽力磁性矿物为主,平均粒度为准单畴(PSD).根据磁性矿物的粒度和低矫顽力组分的相对含量,这5处细粒沉积物可以划分为3种类型:第1种类型是朝鲜海峡西岸细粒沉积物,其磁性矿物的粒度最粗,低矫顽力组分的相对含量为中等;第2种类型是南黄海东南部陆架细粒沉积物,其磁性矿物的粒度为中等,低矫顽力组分的相对含量最大;第3种类型是山东半岛北部近岸、闽浙沿岸(舟山群岛近岸)和济州岛西南陆架区的细粒沉积物,其磁性矿物的粒度最细,低矫顽力组分的相对含量最低.在这5处细粒沉积物中,闽浙沿岸(舟山群岛近岸)细粒沉积物的磁性矿物含量最高,其他4处细粒沉积物的磁性矿物含量都较低且大体相当.这种磁学特征的差异反映了物源的不同.从磁学特征来分析,济州岛西南陆架区的泥质沉积物主要来自黄河和长江;南黄海东南部泥质区的主要物源是朝鲜半岛进入黄海的河流,黄河和长江对其没有重要贡献.     

Research Progress on Source-to-Sink Transport Processes of Marine Microplastics

Microplastics in marine environment are global environmental issue and challenge and have received an extensive international concern. At present, most of researches focus on the investigation of microplastic abundance in the ocean surface water, and there is insufficient understanding of the distribution and transport processes of microplastics in the deep-sea environment. This paper reviewed marine microplastic studies carried out in the last decade, and summarized the source, global distribution and transport processes of microplastics. Field investigations showed that both surface water and water column were important accumulation areas for microplastics, while deep-sea surface sediments were final sinks for microplastic deposition and accumulation. Transport of microplastics to the deep sea included two modes: vertical settlement and lateral transport. Laboratory simulation showed that the sinking rate of microplastic particles in the ocean changed between 300 and 1 000 meters per day, and the sinking process was not solely controlled by particle physical properties such as particle density, but also influenced by ocean dynamic process, biological action and marine snow aggregation. Microplastics deposited on the seafloor could migrate laterally towards the deep sea with resuspended sediments, which were related to internal waves, deep-sea turbidity current or climatic events. However, there remain the key knowledge gaps in uncertain speed and quantity of microplastics moving to the deep sea, which is not conducive to the comprehensive understanding of the microplastic transport process from source to sink. Therefore, it is recommended to observe the vertical sinking flux of microplastics with layered sediment traps in order to study the source-to-sink transport processes of microplastics in deep-sea environment.     

南海古海啸重建与海啸沉积研究进展

中国东海、南海等近海临近琉球海沟、马尼拉海沟等俯冲带,地震频发。过去的海啸研究主要关注历史文献分析、海啸数值模拟等,据此评估中国近岸海啸灾害的历史和风险。历史时期是否引发了海啸,特别是具有特大致灾风险的大海啸记录,目前还不明确。近年来,本课题组通过对海岛、海洋沉积和海岸带及其岛屿的沉积过程、海啸遗迹和历史记录研究,阐述了确定古海啸的系列研究方法。首先通过对南海西沙群岛东岛湖泊沉积序列、大量砗磲和珊瑚块在海岛分布的特征分析,识别出距今千年的一次海啸事件。以此为标志,根据湖泊沉积结构作为识别海岛海啸沉积的特征。同时提出了确定海岛海啸发生时代的样品采集和定年方法,其中包括根据事件沉积层顶部和底部植物残体¹⁴C年龄定年和历史文献记录的印证。首次确定在过去1 300年中,南海发生过一次海啸,其发生时间为公元1076年。为了寻找更古老的海啸记录,结合对东海闽浙沿岸过去两千年海洋泥质沉积的分析,发现南海海啸在沉积序列中留下记录,但除此之外沉积记录中并无更强的扰动,因此东海在过去两千年中受到海啸的影响较小。1076年的海啸同时冲击了南海沿岸,通过对广东南澳岛考察发现,岛屿东南海岸保存着距今约1 000年的海啸沉积层,其中夹杂着宋代陶器瓷器残片。对遗迹数量变化的分析显示,岛上的文化受海啸破坏出现了长达500年的文化中断,直至明代中后期设镇之后才逐渐恢复。根据海啸层植物残体、贝壳¹⁴C测年、覆盖海啸层的海砂光释光定年以及瓷器碎片的年代鉴定了海啸的发生时代,并据此提出了海岸带古海啸沉积的定年方法。此外,不同环境下海啸沉积的特征也存在较大区别,需要结合地形、沉积物来源以及地球化学特征等多种指标进行识别。有迹象表明海南岛东侧海岸带有海啸破坏的明显证据,需要进行深入的研究。     

中国近海天然气水合物找矿前景

天然气水合物是一种新型能源，在海底沉积物和陆上永远冻土带中均有广泛分布。西太平洋是全球三大天然气水合物成矿带之一，在其中已发现许多水合物矿床或矿点。中国近海，包括南海、东海和台湾东部海域，具备良好的天然气水合物成矿条件和找矿前景，并已在这些海域中发现了一系列的找矿标志。南海的西沙海槽、台湾西南陆坡和台西南盆地、笔架南盆地及其东缘增生楔、东沙群岛东南坡、南部陆坡区，东海的冲绳海槽和台湾东北部海域是中国近海最有利的天然气水合物找矿远景区。     

中国区域碳循环研究进展与展望

中国陆地和海洋生态系统的区域碳循环在全球碳循环过程中占有重要地位。目前,中国陆地生态系统在全球碳循环中的地位和作用已有比较深入的研究,而中国边缘海系统碳循环研究相对薄弱。简要回顾中国碳循环（以现代过程的描述为主）的研究动态,重点阐述中国边缘海碳循环研究概况及CO2的海-气交换、有机碳循环、颗粒有机碳的输出、河流的输运等海洋碳循环过程的关键科学问题。在汇总补充及数据更新的基础上勾画了中国区域碳循环框架。我们认为,中国的区域碳循环过程尚有诸多未知量和不确定性,缺乏把陆、海、气作为一个系统的综合研究,海洋生态系统碳循环研究尤其需要加强。中国边缘海的碳循环研究应当围绕CO2的汇源过程这一碳循环的中心问题,深入开展边缘海碳的生物地球化学及其与大气CO2的耦合作用等方面的研究。     

Microplastic contamination in lacustrine sediments in the Qinghai-Tibet Plateau: Current status and transfer mechanisms

This paper aims to investigate the present situation and transfer mechanisms of microplastics in lacustrine sediments in the Qinghai-Tibet Plateau. The study surveyed the average abundance of microplastics in sediments. The abundance of microplastics in sediments of lakes from the Qinghai-Tibet Plateau is 17.22–2643.65 items/kg DW and 0–60.63 items/kg DW based on the data of the Qinghai Lake and the Siying Co Basin. The microplastic abundance in sediments from small and medium lakes is very high compared to that in other areas in the world. Like microplastics in other lakes of the world, those in the lakes in the Qinghai-Tibet Plateau mainly include organic polymers PA, PET, PE, and PP and are primarily in the shape of fibers and fragments. The microplastic pollution of lacustrine sediments in the Qinghai-Tibet Plateau is affected by natural changes and by human activities, and the concentration of microplastics in lacustrine ecosystems gradually increases through food chains. Furthermore, the paper suggests the relevant administrative departments of the Qinghai-Tibet Plateau strengthen waste management while developing tourism and pay much attention to the impacts of microplastics in water environments. This study provides a reference for preventing and controlling microplastic contamination in the Qinghai-Tibet Plateau.©2022 China Geology Editorial Office.     

中国近海天然气水合物的研究进展

南海、东海具有形成天然气水合物的良好动力学环境和丰富的烃类气体来源。根据卫星对海面增温异常的观测、底水气体地球化学、标志矿物和流体组成的研究表明 ,南海、东海海底存在强烈的烃流体活动和排气作用 ;南海南北陆坡区海底气体主要由CH4组成 ,前者多为微生物成因气 ,后者多为热解气 ;冲绳海槽热液沉积区的气体 ,主要为CO2 (86 % ) ,其次为CH4、H2 、H2 S(14 % ) ,分别来自岩浆流体及陆源有机质的降解 ,也属热解成因气。地震地球物理的研究主要集中于南海东北部、北部、南部陆坡区和冲绳海槽中南部 ,测线长度还很有限 ,虽然都有BSR标志的发现 ,但质量比较好 ,研究程度也比较高的还只有南海东北部主动陆缘和北部被动陆缘的一些海域。通过沉积物烃含量和热释光的研究 ,南海、东海共获得 6个地球化学异常区。在综合对比物化探、地热等项资料的基础上初步认为 :笔架南 (Ⅰ )、台西南—东沙 (Ⅱ )异常区是寻找水合物的最佳远景区 ;琼东南—西沙海槽(Ⅲ )、中建南—中业北 (Ⅳ )和冲绳海槽南部异常区是寻找水合物和常规油气藏的有利地区 ,但Ⅳ区更有利于寻找油气 ,其余 2区更有利于寻找水合物 ;南沙海域的研究程度总体上比较低 ,但在其中的南沙海槽 ,物化探异常标志均优 ,甲烷含量较其它地区高 2个数量级     

南海岩石圈结构与油气资源分布

南海是中国唯一发育有洋壳的边缘海,是世界四大海洋油气聚集中心之一。油气勘探表明,南海的油气田分布在北部、西部和南部陆缘沉积盆地内,而大中型油气田集中分布在西部海域盆地中,自北而南有莺歌海—琼东南盆地、万安盆地、湄公盆地、曾母盆地和文莱—沙巴盆地,且以含气为主,含油次之。此外,这一区域深水区还存在多个潜在的大型含油气盆地。研究发现,南海的油气分布与深部岩石圈结构有密切关系。在构造上,南海的含油气盆地位于岩石圈块体边缘或之上,受控于大型岩石圈断裂的发育与演化。在油气富集的盆地中,莫霍面显著凸起,与盆地基底形成镜像,地壳厚度最薄处仅数千米厚,热流值明显较周围地区高,热岩石圈厚度大大减薄。地震层析成像结果反映,这些盆地深部发育一条规模宏大的北西向上地幔隆起带,自红河口向东南穿越南海西部海盆,一直延伸到婆罗州东北部地区,在宏观上控制了南海的油气分布与富集。     

南海北部晚更新世以来的古海洋环境演化特征——来自N-31柱样的沉积记录

对南海北部N-31柱状样沉积物进行了浮游有孔虫定量分析鉴定、氧碳同位素、碳酸盐含量和粒度测试以及AMS14C测年,并采用古生态转换函数计算了表层海水古温度和温跃层深度,揭示了该海区约55 ka以来的古海洋环境特征.转换函数计算的表层海水古温度结果表明,夏季温度的变化范围为27.0～29.6℃,变化幅度为2.6℃,冬季温...     

古南海构造属性及其与特提斯和古太平洋构造域的关系

为了进一步理解南海地区前新生代的构造演化过程,明确古南海构造属性及其与特提斯和古太平洋构造域的关系,通过对古南海遗迹（蛇绿岩、蛇绿混杂岩以及俯冲增生带）的研究,结合周围陆区地质及古生物资料,将古南海的演化划分为4个阶段。①古特提斯残留海阶段（T₁-T₂）:古南海是在早-中三叠世的古特提斯残余海基础上发展而来,与古特提斯残余海是一个连续的演化过程。②古太平洋边缘海阶段（T₃）:晚三叠世,由于古特提斯洋的全面关闭,古南海主要受古太平洋的影响。③中特提斯与古太平洋叠加影响阶段（J-K₁）:早侏罗世,古南海开始扩张,并受中特提斯和古太平洋叠加影响;晚侏罗世,南沙地块向华南大陆开始漂移,古南海进一步强烈扩张。④俯冲消亡阶段（K₂末期-E）:晚白垩世,南沙地块开始裂离华南大陆,古南海开始向南俯冲;至始新世,伴随着新南海的扩张,古南海加速消亡于巽他地块之下,并在南海南部地区形成了卢帕尔线蛇绿岩带以及一系列的俯冲增生带。     

南黄海沉积物常量元素组成及物源分析

通过对南黄海295个站位沉积物样品的常量元素含量分析,研究了南黄海沉积物常量元素组成的R-型聚类分析、R-型因子分析及与物质来源的关系。南黄海沉积物常量元素Al2O3、MgO、K2O、Fe2O3分布基本相似;SiO2分布与Al2O3、MgO、K2O、Fe2O3分布相反;中、西部CaO、CaCO3分布与黄河、长江物源有明显关系;Na2O分布与黄河物质供给有关;TiO2分布反映了长江物质的运移方向。现代黄河物质及老黄河物质主要沉积于南黄海的西部、中部和东南部;海区东部物质反映来自朝鲜半岛物质的对南黄海东部的作用。长江物质主要局限于南黄海的西南和南部区域沉积;TiO2和Ti/Al分布反映了长江物质可能对南黄海中部区域也有所影响。     

中国天然气水合物调查研究现状及其进展

天然气水合物大致经历了实验室研究、管道堵塞及防治、资源调查与开发利用4个发展阶段,中国目前正处于资源调查阶段的早期。自1999年开始,中国先后开展了南海、东海、陆上冻土区和国际海底区域天然气水合物的调查研究,相继发现了一系列地质、地球物理和地球化学异常标志,并在南海北部神狐地区成功采到水合物实物样品,取得了找矿工作的重大突破,显示出良好的找矿前景,但目前仍存在着调查研究程度较低、技术装备比较落后等问题。随着国家对天然气水合物重视程度的加强,中国天然气水合物的调查研究进程将会将进一步加快,并在不久的将来过渡到试生产阶段和商业性生产阶段。     

Microplastic pollution in surface water and sediments of Qinghai-Tibet Plateau: Current status and causes

To study the current status and causes of the microplastic pollution in surface water of the Qinghai-Tibet Plateau, this paper compared the average microplastic abundance in sediments and surface water of the Qinghai-Tibet Plateau and the results are as follows. First, the average microplastic abundance in surface water of the independent rivers and the whole area is 247–2686 items/m³ and 856 items/m³, respectively. The average microplastic abundance in sediments of independent rivers or lakes and the whole area is 0–933 items/m² and 362 items/m², respectively. Meanwhile, the degree of microplastic pollution in river sediments is higher than that in lake sediments, and the rivers suffering from microplastic pollution mainly include the Brahmaputra River, Tongtian River, and Nujiang River. Second, compared with the microplastic pollution in other areas of the world, the levelof microplastic pollution in the lakes and rivers of the Qinghai-Tibet plateau is not lower than that of well-developed areas with more intensive human activities. Finally, this study suggests that relevant government departments of the Qinghai-Tibet Plateau should strengthen waste management strategies while developing tourism and that much attention should be paid to the impacts of microplastics in the water environment.©2021 China Geology Editorial Office.     

从东海石油地质重要进展看西太平洋大陆边缘新生代盆地的构造演化——一种海沟向洋后退的残余弧后盆地演化模式

东海盆地石油地质研究在近二十年里主要取得五方面的进展 :证明了盆地是由一组大陆边缘新生界由西向东逐个变新的“盆地群体”组成 ,建立了陆架地区以组为单位的整个新生代地层单元 ,详细划分了西湖凹陷的内部地质结构 ,认定了煤和煤系沉积是东海陆架区的主力油气源岩 ,通过大量钻井验证了盆地中三类不同成因的圈闭。从环西太平洋盆地形成的地球动力学背景看 ,西太平洋是一个自北而南的沟—弧—盆 (陆缘海 )系统 ;大体以台湾海峡为界 ,东海盆地是一个由转换或被动边缘演化而来的聚敛边缘 ,而南海属于由活动或聚敛边缘转化而来的被动边缘。东海盆地与菲律宾海盆地具有相似的时空演化特征 ,由此论证了东海新生代盆地属于残余弧后向洋后退盆地