Basin-scale seawater lead isotopic character and its geological evolution indicated by Fe-Mn deposits in the SCS

Abstract

The geochemical characteristics and Pb isotope variations in Fe-Mn deposits collected from the South China Sea (SCS) were studied in this paper. The mineralogical and chemical composition data indicate that the deposits are almost all hydrogenetic in origin. Compared with the Fe-Mn deposits in other oceans, the SCS Fe-Mn deposits have a significantly higher Pb content because of higher material supply in addition to a lower growth rate of the deposits. Pb isotope ratios in the surface of the SCS Fe-Mn deposits are relatively uniform, with a characteristic of relatively lower ²⁰⁶Pb/²⁰⁴Pb ratio. The Pb isotopic compositions of the SCS Fe-Mn deposits are controlled by the Pacific Deep Water and local inputs, which include eolian dust from the Asian continent and weathering products from Taiwan, Luzon and SCS submarine volcanic rocks. The continuously increasing ²⁰⁶Pb/²⁰⁴Pb, ²⁰⁷Pb/²⁰⁴Pb and ²⁰⁸Pb/²⁰⁴Pb ratios along the transect of nodule D581 over the past 3.5?Ma are affected by the stepwise closure of the Luzon Strait that reduced volcanic material supply and the deep current strengthen at the same time.     

南极长城湾全新世有孔虫研究

南极长城湾９３Ｉ（６２°１７．７４′Ｓ，５８°４９．９１′Ｗ）柱样含有较丰富的有孔虫动物群，计鉴定统计５１９００个体，归属于８６种，有孔虫总丰度以柱样中段较低，浮游类含量较低（〈５％）钙质类底栖有孔虫成占优势，全柱底栖有孔虫分异度变化范围不大，底栖有孔虫五个优势种的优势度占决量的８３．３％，优势种及其组合变化显著一定的古海洋学意义，探讨了长城湾海区晚第四纪环境变迁，为南大洋晚第四纪环境与全球变化关     

TEMPERATURE, RAINFALL VARIATIONS AND THEIR ANOMALIES OVER CHINA UNDER THE COLD-WARM BACKGROUND IN THE 20TH CENTURY*

In this study,the climate trend of the annual average air temperature and total annual rainfall in China in the present century has been examined.It is noted that in the Northwest,the Northeast and North China the climate has become notably warmer this century but the rainfall trend has not been evident,mainly negative.In the 1980s China's rainfall and temperature showed noticeable regional features:warm and dry in North China,cold and dry in the Southwest,warm and wet in the Northeast,cold and wet in the middle-lower reaches of the Changjiang River.Besides,the four interdecadal climate change features and ranges of this century have been studied.It is found that on the scale of several decades there was considerably less rainfall in the most part of China in the warm background than in the cold background.The increase of temperature which started from the 1970s mainly happened in the Northwest and Northeast,while to the south of the Huanghe River the temperature increase did not even as great as in 1940s.The corresponding rainfall feature is that most areas experienced much less rainfall except the area to the south of the Huanghe River and over the Changjiang and Huaihe River basin.     

新疆天山金矿可持续发展建议

新疆天山成矿带是我国重要的金成矿带,主要发育韧性剪切带型、火山型和穆龙套型3种类型金矿床。随着社会经济的快速发展,黄金的需求量在逐年增大,这就要求新疆对金矿的勘查开发要加大力度。本文通过研究新疆天山金矿的特征并就可持续发展提出建议。     

高钾系列复混喷施肥的研制与应用

所研制的高钾系列复混喷施肥其成份以KNO3为主,含微量营养元素。应用试验表明,该喷施肥具有成本低,肥效高,经济效益显著的特点,具有推广应用价值。     

Cosmic rays at ultra high energies (Neutrinos!)

Resonant photo-pion production with the cosmic microwave background predicts a suppression of extragalactic protons above the famous Greisen–Zatsepin–Kuzmin cutoff at about E_GZK ≈ 5 × 10¹⁰ GeV. Current cosmic ray data measured by the AGASA and HiRes Collaborations do not unambiguously confirm the GZK cutoff and leave a window for speculations about the origin and chemical composition of the highest energy cosmic rays. In this work we analyze the possibility of strongly interacting neutrino primaries and derive model-independent quantitative requirements on the neutrino–nucleon inelastic cross section for a viable explanation of the cosmic ray data. Search results on weakly interacting cosmic particles from the AGASA and RICE experiments are taken into account simultaneously. Using a flexible parameterization of the inelastic neutrino–nucleon cross section we find that a combined fit of the data does not favor the Standard Model neutrino–nucleon inelastic cross section, but requires, at 90% confidence level, a steep increase within one energy decade around E_GZK by four orders of magnitude. We illustrate such an enhancement within some extensions of the Standard Model. The impact of new cosmic ray data or cosmic neutrino search results on this scenario, notably from the Pierre Auger Observatory soon, can be immediately evaluated within our approach.     

The position and role of Wuhan City in the regional economic macro-strategies of China

Taking the development of export-oriented economy (the strength and temporal sequence) as a main line, this paper discusses and analyses the position and role of Wuhan, which is the biggest metropolis in the central China and the middle section of the Changjiang (Yangtze) River basin, in the regional economic macro-strategy of China from a new visual sight. On the basis of the background of a large economic triangle constructed by Hongkong, Wuhan and Shanghai, the paper discusses the relations between Wuhan and Hongkong, Wuhan and Shanghai. The aim of the paper is to provide some new evidences for the development of great regional economy of China under the copropelling of the three great economic pivots. Supported by the National Natural Science Foundation of China.     

应用CRInSAR技术监测三峡库区滑坡形变

在对CRInSAR技术的基本理论和处理算法及实际应用进行研究的基础上,比较CRInSAR技术与传统InSAR技术的异同后认为,CRInSAR技术更适合三峡库区的滑坡监测。     

中国大陆西部地区现今的块体运动

根据中国地壳运动ＧＰＳ监测网１９９２～１９９６年３次复测结果,分析了我国大陆西部地区现今块体运动的基本特征,结果表明：印度板块向北推挤是我国西部块体褶皱运动和变形的根源;由於内部次级断块的边界条件和受力方式不同,块体边界和内部构造形变亦具有明显的差异。块体运动主要特点表现为：（１）喜马拉雅向南弯曲的弧形边界东西两端,印度板块推挤运动方向不同,导致了弧前方的亚板块和构造块体的运动方向呈扇形散开;（２）青藏高原主体在南北向缩短、东西向延伸的同时存在着明显向东的物质侧向滑移;（３）重要块体分界带和褶皱带两侧运动矢量的比较表明,阿尔金断裂为左旋走滑,天山、祁连山均呈压性;（４）由设置在不同块体的ＧＰＳ测站南北向和东西向运动速率及速率的平均值得到的块体运动速率和方向,呈有规则的变化,其变化规律与地质、地球物理结果具有较好的一致性。     

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