High-resolution sedimentary record of lead in the coastal mud of the East China Sea in the past one hundred and fifty years

In the East China Sea （ECS）, there are some mud areas, including the south coastal mud area, the north coastal mud area, and the mud area to the southwest of Cheju Island. X-ray fluorescence （XRF） techniques and Thermal Ionization Mass Spectrometry （TIMS） were used to study the high-resolution sedimentary record of Pb concentrations and Pb stable isotopic compositions in the past one hundred and fifty years in the coastal mud of the ECS. Pb concentrations of a ^210Pb dating S5 core in the study area have increased rapidly since 1980, and reached the maximal value with 65.08 μg/g in 2000, corresponding to the fast economic development of China since the implementation of the ＂Reform and Open Policy＂ in 1978; ^206Pb/^207Pb ratios generally had stabilized at 1.195 from 1860 to 1966, and decreased gradually from 1966 to 2000, indicating that the anthropogenic source Pb contribution to the ECS has increased gradually since 1966, especially since 1980. Pb concentrations decreased distinctly from 2000 to 2003 and ^206Pb/^207Pb ratios increased from 2001 to 2003, corresponding closely to the ban of lead gasoline from 2000 in China. From 1950 to 2003, there occurred four distinct decrease events of ^206Pb/^207Pb, possibly responding to the Changjiang River （Yangtze River） catastrophic floods in 1998, 1991, 1981 and 1954; from 1860 to 1966, there were two decrease periods of ^206Pb/^207Pb, which may respond to the catastrophic floods of Changjiang River in 1931 and 1935, and 1870. As a result of the erosion and drowning by the catastrophic floods, the anthropogenic lead accumulated in soil and water environments over a long period of time was brought into the Changjiang River, then part of them was finally transported into the ECS, which leads to changes in Pb stable isotopic composition.     

东海陆架泥质区沉积有机质的物源分析

色谱和色谱／质谱分析表明，济州鸟西南泥质区正构烷烃、姥鲛烷、植烷、藿烷和甾烷等生物标志物的特征与现代长江口、老黄河口和新黄河口的河流沉积物均区别很大，该泥质区的沉积有机质主要来源于海洋低等生物（如细菌和藻类等）以及陆源高等植物的输入，表现为不同来源和成熟度的生物标志物的混合，同时该泥质区沉积有机质与矿物碎屑沉积物来源不尽相同。长江口泥质区正构烷烃高相对分子质量部分与长江口沉积物相似，正构烷烃和藿烷所反映的有机质成熟度高于现代长江和老黄河口沉积物，甾烷的成熟度与长江相仿而明显高于老黄河口沉积物。长江口泥质区的沉积有机质主要来源于长江输入的陆源高等植物碎片和海洋源的低等生物。东海陆架近岸与远端泥质区沉积有机质的物源很不相同。     

中国构造地质学发展：百年回顾与展望

一百年以来,中国构造地质学学科发展经历了二十世纪初期萌芽孕育、早期发展和多学派大地构造学说百家争鸣。构造地质学专业委员会的成立和发展,标志着我国构造地质学的教育与研究进入一个新的发展时期。专业委员会长期以“服务国家战略需求、搭建学术交流平台、促进学科前沿发展和开展科学普及”为宗旨,主办、组织召开了系列全国性构造会议和现场研讨会议,搭建全国性和国际性的学术交流平台。我国构造地质学家吸收和借鉴国际先进大地构造和构造地质学理论,以环太平洋洋 陆过渡带、特提斯构造域和古亚洲构造域,特别是青藏高原动力学演化研究为引领,针对地球不同圈层相互作用、互馈机理与动力学,开展板块构造起源与早期地球演化、大陆的生长与再造过程、洋 陆系统演化与深部地球动力学、大陆构造变形与宜居地球系统、活动构造, 对资源 环境 灾害的影响等领域开展了研究工作,取得了丰硕的成果。尤其是在新世纪以来,在青藏高原形成演化、华北克拉通破坏、中亚增生型造山带等多个领域取得具有国际水平的研究成果。在构造地质学发展的新阶段,我国构造地质学学科的发展将强化学科基础,推进原创性、创新性理论探索,深化发展板块构造理论,力争在东亚洋陆构造格局与转变、大陆构造变形与人类宜居的地球系统等方面的理论研究上取得原始创新与突破,参与国际地学发展与竞争并作出贡献。     

A one hundred and seventeen year coastal water temperature record from Woods Hole,Massachusetts

We have compiled what we believe is the longest coherent coastal sea surface temperature record in North America. Near-surface water temperature measurements have been made almost daily at Great Harbon, Woods Hole, Massachusetts, since 1886 with remarkably few gaps. The record shows that there was no significant trend in water temperature at this site for the first 60 yr of observation. There was some cooling during the 1960s that was followed by a significant warming from 1970–2002 at a rate of 0.04°C yr^?1. During the 1990s annual mean temperatures averaged approximately 1.2°C warmer than they had been on average between 1890 and 1970; winter (December, January, and February) temperatures were 1.7°C warmer and summer (June, July, and August) temperatures were 1.0°C warmer. There has not been a statistically significant decrease in the annual number of winter days below 1°C or an increase in the annual number of winter days above 5°C. The number of summer days each year with water temperature above 21°C has not increased significantly. The dates of first observations of 10°C and 20°C water in the spring have not changed sufficiently to be statistically significant. There is a weak positive correlation between annual and winter water temperature and the annual and winter North Atlantic Oscillation index, respectively, during the period of record.     

Holocene climate variability and cultural evolution in the Near East from the Dead Sea sedimentary record

A comprehensive record of lake level changes in the Dead Sea has been reconstructed using multiple, well dated sediment cores recovered from the Dead Sea shore. Interpreting the lake level changes as monitors of precipitation in the Dead Sea drainage area and the regional eastern Mediterranean palaeoclimate, we document the presence of two major wet phases ( 10–8.6 and  5.6–3.5 cal kyr BP) and multiple abrupt arid events during the Holocene. The arid events in the Holocene Dead Sea appear to coincide with major breaks in the Near East cultural evolution (at  8.6, 8.2, 4.2, 3.5 cal kyr BP). Wetter periods are marked by the enlargement of smaller settlements and growth of farming communities in desert regions, suggesting a parallelism between climate and Near East cultural development.     

近70年滇池有机质来源和生产力变化的沉积记录

总有机碳(TOC)、稳定碳同位素(δ¹³C)、岩石热解分析(Rock-Eval)和甾醇生物标志物等有机地球化学指标用于研究滇池过去70年沉积物有机质的来源及水体生产力的变化。C/N、δ¹³C、氢指数(HI)表明滇池沉积物有机质主要为水生来源, 且主要为藻类有机质。初级生产力指标(热解烃峰参数(S2)、HI、δ¹³C)和浮游植物甾醇(菜籽甾醇、甲藻甾醇)含量从2000年以后快速增加, 而从近几年开始增速放缓或开始下降, 说明滇池水体生产力在过去几十年不断上升, 不过在最近得到一定控制, 这与滇池沉积物营养盐的变化趋势相似。对生产力指标和浮游植物甾醇与环境因子如5年移动平均气温(T₅)、总氮(TN)、总磷(TP)进行相关分析, 结果表明滇池生产力变化与环境因子呈现显著的正相关关系, 说明气候变暖和营养盐增加均促进该水域藻类的繁殖; 此外, 多元线性回归分析结果表明, TN是影响滇池生产力变化的主要环境因子。研究结果对探寻水体富营养化过程及影响因子, 并对湖泊管理和水华防治工作提供科学依据。

     

近2000年南海北部沉积有机碳的来源及埋藏记录

在气候变化和人类活动日益增强的背景下, 河口近海碳源汇途径的变化对区域乃至全球碳循环有着深刻的影响。本研究对南海北部河口-近岸-陆架海区3根沉积物柱状样顶部沉积记录约2000年的样品进行了有机碳(TOC)和总氮(TN)含量与稳定同位素组成等地球化学指标的分析。结果显示, 南海北部沉积物TOC含量在过去2000年表现出稳步增加的趋势。根据稳定碳同位素(δ¹³C)和TOC/TN比值构建的蒙特卡洛模拟估算, 发现不同海区沉积有机碳的来源存在差异, 其中陆源有机碳在近岸区贡献最高, 河口区次之, 南海北部陆坡贡献最小。在时间尺度上, 陆坡区TOC来源在过去2000年维持稳定, 而河口近岸区中海源有机碳比例不断增加, 特别是河口区海源有机碳在过去1000年快速增加, 同时与TN的变化存在显著的正相关关系, 反映了人类活动持续输入的陆源营养盐促进了海洋初级生产力的升高; 另一方面, 河口区陆源有机碳的减少主要归因于华南地区减弱的东亚夏季风和人类活动与沿海地区大规模的围垦活动等。不同于河口近岸海区, 南海北部陆坡沉积物有机碳埋藏的增加主要与东亚冬季风增强对营养盐供应和初级生产力的调控密切关联。整体而言, 人类活动和气候变化共同控制着近2000年南海北部沉积物有机碳埋藏的演变过程。

     

黄海和东海沉积物有机质活性及营养盐再生潜力初探

2000年秋季和 2001年春季,对黄海和东海 6个站位的水柱和沉积物样品进行了营养盐、沉积有机碳、有机碳同位素和氨基酸分析.结果表明, 表层沉积物的有机碳含量和有机质活性存在较明显的季节性变化,这主要由春秋两季表层水体生物量的差异引起.在泥质堆积区 E2、 E4、 E5站,春季表层沉积物有机碳的含量与活性均较高,而同期底部沉积物向上的营养盐梯度也明显增大, 显示有机碳的含量及活性与营养盐再生有密切关系.     

东海陆架全新统高分辨率层序地层学研究

在高分辨率14C测年、岩石、生物、化学、同位素、气候及磁性地层学研究成果基础上,通过不同沉积背景典型钻孔的沉积学分析,运用层序地层学理论,对东海陆架全新统进行了高分辨率层序划分及对比;建立了全新世层序地层格架及海平面变化过程;提出了相应的层序成因模式。研究结果表明,东海陆架全新统相当于一个发育中的六级（1~10ka）层序,可进一步划分为3个七级（0.1~1ka）层序和若干个更次级层序。代表1个六级或3个七级周期相对海平面变化过程中叠加有若干更次级的海平面波动,它们与地球旋回谱系中的太阳带、历法带密切相关。七级层序具有与三级层序相近的内部构型和成因格架。在东海陆架全新世沉积演化过程中,长江三角州至少有3次不同程度地越过东海陆架进入冲绳海槽,并滞留有至少3层海侵改造"残积砂"沉积。在东海陆架全新世海平面变化期间,最大海平面时期为约距今6~5ka,大致高于现今海平面2~4m,最低海平面在距今10ka左右,大约低于现今海平面130m。目前,由于温室效应的影响,海平面仍呈小幅度波浪式上升。事实证明,层序地层学不仅丰富了现代海洋沉积学的内容,而且解决了许多海洋沉积学未能解决的问题.     

未来百年全球气候变化分析

未来百年全球气候变化的影响是当前学术界激烈争议的议题,深入探讨全球气候变化的驱动机理才能正确认识全球气候变化.持续生长的青藏高原吸收了巨量的CO2,导致大气中CO2浓度大幅下降,使地球从温室气候进入到以冰期、间冰期交替出现为特征的冰室气候,青藏高原成为新生碳储库.在间冰期,青藏高原和蒙古高原将淡水输送到中低纬度内陆区(...     

Temporal trends of aliphatic and polyaromatic hydrocarbons in the Bohai Sea, China: Evidence from the sedimentary record

This work reports the historical trends and sources of aliphatic hydrocarbons (AHs) and polycyclic aromatic hydrocarbons (PAHs) in two ²¹⁰Pb dated sediment cores extracted from the central mud areas of Bohai Sea (Bohai). The TOC/TN ratio of the bulk organic matter (OM) and the composition of the n-alkanes suggest that the sedimentary organic matter was of mixed marine and terrigenous sources. The coarser sediment grain size and decreasing C/N ratios since ∼1976 could be attributed to the relocation of the Yellow River mouth causing a decreased influence of Yellow River derived sediments and associated OM into the central Bohai. The concentration of total 16 PAHs in the two cores ranged from 34.2-202 ng/g (mean, 91.5) for BC1, and from 53.3-186 ng/g (mean, 103) for BC2, with a high abundance of 2-3 ring PAHs. Perylene in the two cores mainly originated from terrigenous sources via riverine discharge and thus could be potentially related to changes in the sediment load from the Yellow River into the Bohai over time. Petroleum inputs could be revealed by ratios of methylphenanthrenes to phenanthrene (MP/P) and the patterns of more stable geochemical biomarkers (hopanes and steranes) along the two cores, in addition to the presence of unresolved complex mixtures (UCM) in the surface layers. Source diagnostic ratios of PAHs indicated a pyrogenic origin from biomass and coal combustion with a minor petroleum contribution. Downcore trends of compositional PAHs profiles were in agreement with the socio-economic development in China in the past decades. This temporal variation of sedimentary PAHs can also reflect a different evolution stage of energy structure in China as compared with those of the western developed countries.     

近 2 ka来东海内陆架泥质沉积物地球化学特征

对位于东海内陆架闽浙沿岸泥质区北部的 DD2孔进行了粒度分析、 AMS 14C年龄测试和主元素、微量元素分析,讨论了各元素含量与粒度间的关系,采用 R型因子分析探讨了它们间的组合关系.研究表明,近 2 ka来 DD2孔绝大多数主元素和微量元素含量稳定;随粒径变细大部分元素的含量呈现增加的趋势,而 Sr和 SiO2的含量则呈现减少的趋势;CaO、 Na2O、 Hf、 Zr和 Ti等的含量与粒径相关性很差.因子分析的结果表明, DD2孔泥的化学组成可划分为 4种组合类型:分别反映沉积物中元素分布的主要特点,样品未经洗盐前处理引起主元素和微量元素组合的变化, Zr、 Hf和 Nb元素富集于特定粒度组分 (粉砂 ),及钙质生物组分的加入和早期成岩过程中元素的再分配性质等.初步分析表明, Rb、 Cu、 Ni、 V、 P、 Sc、 Fe2O3、 Cr、 K2O、 Nb、 Co、 Th、 Ti和 Al2O3为 DD2孔中相对不活动的元素,可以将它们与现代长江、黄河沉积物作对比,进行物源分析. Ti/Zr和 Cr/Th比值指示该孔沉积物主要来自于花岗质物源区.     

东海泥质区表层沉积物中多环芳烃的分布特征及物源

以 GC/MSD内标法定量测定了东海近岸和远岸泥质沉积区 18个表层沉积物中多环芳烃 (PAHs)的含量,探讨了多环芳烃在这些泥质区的分布特征、影响因素及来源.结果显示 ,近岸泥质区多环芳烃含量普遍较高,介于 180.3～ 424.8 ng/g(干重 )之间;冲绳海槽次之,含量为 211.7 ng/g ;济州岛西南泥质区最低,含量介于 117.1～ 211.7 ng/g之间.东海泥质区多环芳烃的分布主要受控于离物源的远近、沉积物粒度、有机碳含量以及东海环流体系.东海泥质区的多环芳烃主要来源于热成因,大气干湿沉降和河流输入是其进入泥质区的主要途径.东海泥质区多环芳烃的污染程度中等.     

One hundred fifty-year record of lead isotopes in Antarctic snow from Coats Land

A record of the concentrations of Pb and Ba and the isotopic composition of Pb has been established for a remote, low accumulation site in the Atlantic sector of Antarctica (Coats Land) by means of thermal ionization mass spectrometry. The snow samples cover the period ∼1840 to 1990. They were taken from the walls of a pit to a depth of 7.8 m and as a core to 16 m; ultraclean procedures were used. Detailed laboratory subsampling provided both long-term (secular scale) and short-term (intra-annual) Pb, Ba, and Pb isotope variations. The results show that there have been significant variations in Pb concentrations (range, 0.1 to 9.3 pg/g) and isotopic composition (range, 1.096 to 1.208 for ²⁰⁶Pb/²⁰⁷Pb ratio) since the 1840s. The data show evidence of pollution for this metal in Antarctica as early as the 1880s. Several Pb maxima were observed: the first at the beginning of the 20th century and the last in the 1970s to 1980s, with a clear decrease during recent years. Although the last maximum is clearly linked to the rise and fall in the use of leaded gasoline in the Southern Hemisphere, especially in South America, the reason for the first remains uncertain. The pattern of changing isotopic composition of Pb reveals the changing origin and character of the anthropogenic inputs to Antarctica. An interesting feature in this pattern is the relatively large contribution of unradiogenic Pb in the ∼1890s, possibly originating from Australia. Another interesting feature is the pronounced intra-annual variation in the isotopic composition of Pb, which illustrates the complexity of the changing inputs of Pb to Antarctica.     

An 800‐year ultraviolet radiation record inferred from sedimentary pigments in the Ross Sea area,East Antarctica

High performance liquid chromatography (HPLC) combined with mass spectrometry (MS) was used to analyse deposited pigments (including chlorophyll a, phaeophytin a, canthaxanthin, echinenone, zeaxanthin, scytonemin and mycosporine‐like amino acids) from two sediment profiles of ponds in the Ross Sea area, East Antarctica. We explored the sources and characteristics of each pigment, reconstructed an 800‐year record of ultraviolet radiation (UVR) and total incoming light intensity, and identified the possible factors that may have influenced historical UVR changes in this region. The results indicated at least four UVR peaks during the past 800 years, corresponding to c. AD 1950–2000, 1720–1790, 1560–1630 and 1350–1480, with the intensity from the most recent sediments being the highest. A comparison between the changes in UVR and total incoming light intensity showed similar patterns between AD 1720 and 1830, suggesting that factors controlling the UVR intensity in the Ross Sea area may be related to insolation fluctuation at that time. The two proxies are, however, weakly correlated during other periods. Historically, there is a relationship between the reconstructed UVR and solar activity, but this natural process may be strongly affected by multiple factors, including climate parameter change and anthropogenic activities during the modern times.     

Sea level history in Beringia during the past 250,000 years

This paper attempts to relate current knowledge of sea-level history in Beringia to the Broecker-van Donk “Termination” concept of climatic and sea-level history. The Einahnuhtan transgression is thought to represent Termination III, which according to Broecker and van Donk, took place about 225,000 y.a. The Kotzebuan transgression is thought to represent a positive fluctuation that modulated the generally falling sea level during the ensuing 100,000 yr. Sea level probably fell to about ?135 m in the Bering Sea area during the maximum phase of the penultimate glaciation. The two Pelukian shorelines probably represent Termination II (about 125,000 yr BP in the Broecker-van Donk chronology) and one of the two positive fluctuations that modulated the generally falling sea level of early Wisconsinan time, about 105,000 and 80,000 y.a. according to Broecker and van Donk. Another positive modulation brought sea level to at least ?20 m, about 30,000 y.a. Sea level evidently fell to between ?90 and ?100 m during the late Wisconsinan regression, but a substantial part of the outer Bering shelf remained submerged. Submerged shoreline features at ?38m, ?30 m, ?24 to ?20 m, and ?12 to ?10 m represent stillstands or slight regressions that modulated Termination I, the late Wisconsinan, and early Holocene recovery of sea level.     

南海北部夏季沿岸上升流近百年的强度变化

用全谱直读ICP-AES技术测定了海南岛东部（琼东）沿岸上升流区域滨珊瑚1906—1996年的Sr／Ca比值。结果显示珊瑚Sr／Ca比值重建的琼东海域的夏季海表温度偏低,强烈地受到东亚夏季风引起沿岸冷上升流的影响。结合西沙海域的滨珊瑚海表温度记录,首次重建了1906～1993年琼东沿岸风生上升流的强度指数变化序列。结果表明琼东上升流于1906～1993期间整体呈加强趋势,并具显著的年代际波动特征,同全球趋暖密切相关。此外,重建的上升流强度指数序列还揭示了大尺度环流——厄尔尼诺一南方涛动对琼东上升流强度变化的制约。     

东海陆架盆地西湖凹陷渐新世海侵作用与潮控体系沉积特征*

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