Global Sea Level Change and Thermal Contribution

The global long-term sea level trend is obtained from the analysis of tide gauge data and TOPEX/Poseidon data. The linear trend of global mean sea level is highly non-uniform spatially, with an average rate of 2.2 mmyear^-1 in T/P sea-level rise from October 1992 to September 2002. Sea level change due to temperature variation （the thermosteric sea level） is discussed. The results are compared with TOPEX/Poseidon altimeter data in the same temporal span at different spatial scales. It is indicated that the thermal effect accounts for 86% and 73% of the observed seasonal variability in the northern and southern hemispheres, respectively. The TOPEX/Poseidon observed sea level lags behind the TSL by 2 months in the zonal band of 40%-60% in both the northern and southern hemispheres. Systematic differences of about 1-2 cm between TOPEX/Poseidon observations and thermosteric sea level data are obtained. The potential causes tbr these differences include water exchange among the atmosphere, land, and oceans, and some possible deviations in thermosteric contribution estimates and geophysical corrections to the TOPEX/Poseidon data.

Implications of Climate Change on Streamflow of a Snow-Fed River System of the Northwest Himalaya

Air temperature and snow cover variability are sensitive indicators of climate change. This study was undertaken to forecast and quantify the potential streamflow response to climate change in the Jhelum River basin. The implications of air temperature trends （＋0.11℃decade） reported for the entire north-west Himalaya for past century and the regional warming （＋0.7℃/decade） trends of three observatories analyzed between last two decades were used for future projection of snow cover depletion and stream flow. The streamflow was simulated and validated for the year 2007-2008 using snowmelt runoff model （SRM） based on in-situ temperature and precipitation with remotely sensed snow cover area. The simulation was repeated using higher values of temperature and modified snow cover depletion curves according to the assumed future climate. Early snow cover depletion was observed in the basin in response to warmer climate. The results show that with the increase in air temperature, streamfiow pattern of Jhelum will be severely affected. Significant redistribution of streamflow was observed in both the scenarios. Higher discharge was observed during spring-summer months due to early snowmelt contribution with water deficit during monsoon months. Discharge increased by 5%-40% during the months of March to May in 2030 and 2050. The magnitude of impact of air temperature is higher in the scenario-2 based on regional warming. The inferences pertaining to change in future streamflow pattern can facilitate long term decisions and planning concerning hydro-power potential, waterresource management and flood hazard mapping in the region.

上扬子石炭—二叠纪海相碳酸盐的锶同位素演化与全球海平面变化

地质历史中海水的锶同位素组成是时间的函数 ,全球海平面变化是其最主要的控制因素 ,上扬子地区石炭—二叠纪海相碳酸盐的锶同位素演化曲线与海平面变化曲线有着很好的一致性。锶同位素演化曲线说明 :1)早石炭世是一个海水逐渐加深的全球海平面上升时期 ,锶同位素最小值所显示的最大海泛面的年龄为 34 2Ma ,位于杜内阶和韦宪阶的界线上 ;2 )晚石炭世是一个全球海平面下降时期 ;3)整个二叠纪都是全球海平面上升时期 ,晚二叠世的海平面上升不仅幅度大 ,而且海水在短时间内迅速加深 ;4)晚二叠世具有古生代海相碳酸盐的锶同位素最小值 ,显示晚二叠世末的全球淹没事件 ,最大海泛面的年龄为 2 5 0Ma,正好在二叠 /三叠纪界线附近 ;5 )二叠 /三叠纪之交的全球生物绝灭事件可能与二叠世末的全球淹没事件有关。

黑龙江省东部鸡西群地层时代划分及地质意义

利用最新的古生物、磁性地层年代资料及高分辨率层序延续时间推算,对鸡西群进行了精细的年代地层划分,确定了鸡西群形成时间为早白垩世凡兰吟早期—阿尔布中期,其中滴道组形成时间为130.9～128.3Ma,城子河组形成时间为125.1～116Ma,穆棱组形成时间为116～106.9Ma,东山组形成时间为106.9～101.7Ma。通过鸡西群二级层序湖平面升降曲线与全球海平面升降曲线对比,证实了鸡西盆地、勃利盆地的构造运动、古气候演变与全球海平面升降变化有着相同的大地构造背景。这一成果对吉林和黑龙江省东部早白垩世高精度地层划分对比及盆地构造作用与海陆变迁机制分析提供了精确的年代依据。

Major transgression during Late Cretaceous constrained by basin sediments in northern Africa： implication for global rise in sea level

The global rise in sea level during the Late Cretaceous has been an issue under discussion by the international geological community. Despite the signifi- cance, its impact on the deposition of continental basins is not well known. This paper presents the systematic review on stratigraphy and sedimentary facies compiled from 22 continental basins in northern Africa. The results indicate that the region was dominated by sediments of continental facies during Early Cretaceous, which were replaced by deposits of marine facies in Late Cretaceous. The spatio- temporal distribution of sedimentary facies suggests marine facies deposition reached as far south as Taou- deni-Iullemmeden-Chad-A1 Kufra-Upper Egypt basins during Turonian to Campanian. These results indicate that northern Africa underwent significant transgression during Late Cretaceous reaching its peak during Turonian to Coniacian. This significant transgression has been attributed to the global high sea-level during this time. Previous studies show that global rise in sea level in Late Cretaceous may have been driven by an increase in the volume of ocean water （attributed to high C02 concentra- tion and subsequently warm climate） and a decrease in the volume of the ocean basin （attributed to rapid production of oceanic crust and seamounts）. Tectonic mechanism of rapid production of oceanic crust and seamounts could play a fimdamental role in driving the global rise in sea level and subsequent transgression in northern Africa during Late Cretaceous.

全球产出缺口与中国的通胀变动：基于扩展的菲利普斯曲线研究

本文在考察全球产出缺口与国内通胀变动关系的基础上,应用扩展的菲利普斯曲线模型,对影响我国通胀变动的国内外因素进行了经验研究,验证"全球产出缺口假说"在中国的适用性。计量结果表明,国内产出缺口、通货预期、原油价格和食品价格都是影响国内通胀变动的主要因素,贸易加权、进口加权、产出加权的全球产出缺口对国内通胀变动具有正向影响,但影响程度还没有国内产出缺口高。对待全球化背景下中国的通胀变动,不仅要分析国内宏观经济均衡与波动周期,更要关注国际市场的外部冲击。

Variabilities of carbonateδ13C signal in response to the late Paleozoic glaciations,Long’an,South China

An integrated study of biostratigraphy,microfacies,and stable carbon isotope stratigraphy was carried out on the late Famennian–early Asselian carbonates of the Long’an section in Guangxi,South China.Stable carbon isotope studies in the Long’an section have revealed four major positive shifts ofδ13C values in the Carboniferous strata in South China.The first shift occurred in the Siphonodella dasaibaensia zone in the Tournaisian,with an amplitude of 4.19‰.The second shift occurred near the Visean/Serpukhovian boundary,with an amplitude of 2.63‰.The third shift occurred in the Serpukhovian,with an amplitude of 3.95‰.The fourth shift occurred in the Kasimovian,with an amplitude of 3.69‰.Furthermore,there were several brief positiveδ13C shifts during the late Famennian to early Tournaisian.All of these shifts can be well correlated globally,and each corresponds to sea-level regressions in South China and Euro-America,indicating increases in ocean primary productivity and global cooling events.Chronologically,the four major positive excursions ofδ13C,together with several brief positiveδ13C shifts that were observed during the late Famennian to the early Tournaisian,correspond to the well-accepted Glacial I,II,and III events.