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Science China Earth Sciences 2005年第10期48卷 1718-1727页

作者： Yokoyama Kazumi Department of Geology National Science Museum Tokyo Japan

The Late Cenozoic strata are 313 m thick, revealed by the drilling core PD-99 in the south Changjiang delta. Monazite chemical dating shows that 350-500-Ma monazites predominate in the Pliocene and 100-275-Ma monazites in the Quaternary, indicating a great change of their provenance. The first presence horizon of monazites younger than 25 Ma is just above the Matruyama/Gauss boundary (~2.58 Ma), whch is exactly when uplift of the Tibetan Plateau began to influence deposition in the East China Sea. Variations in contents of monazites younger than 25 Ma can be divided into two sections. The Early-Middle Pleistocene with less <25 Ma monazites corresponds with rapid uplift of the Tibetan Plateau, and the Late Pleistocene with more <25 Ma monazites parallels the peak uplift of the Tibetan Plateau. This study demonstrates that chemical dating of monazites in the river-mouth strata is a useful method to explore changes of river drainage basins, and deconvolute multistage tectonic and magmatic activity histories in the provenance areas.

关键词： delta, monazite, electron microprobe, chemical dating, formation of the Changjiang, uplift of the Tibetan Plateau.

Characteristics of vertical ozone distribution in the lower troposphere in the Yangtze River delta at Lin'an in the spring of 2001

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Science China Earth Sciences 2005年第9期48卷 1519-1528页

作者： ZHENG Xiangdong1, CHAN Chuenyu2, CUI Hong2, QIN Yu3, CHAN Loyan2, ZHENG Yongguang3 & LEE Yusiang2 1. Chinese Academy of Meteorological Sciences, Beijing 100081, China 2. Department of Civil and Structural Engineering, Hong Kong Polytechnic University, Hung Hom, Hong Kong, China 3. Department of Atmospheric Sciences, Peking University, Beijing 100871, China Chinese Academy of Meteorological Sciences Beijing China Department of Civil and Structural Engineering Hong Kong Polytechnic University Hung Hom Hong Kong China Department of Atmospheric Sciences Peking University Beijing China

We analyzed vertical distributions of ozone (O3) in the lower troposphere (< 5 km above ground) at Lin’an (119.75°E, 30.30°N), Zhejiang Province using electrochemical concen- tration cell (ECC) ozonesonde data obta...

We analyzed vertical distributions of ozone (O3) in the lower troposphere (delta (YRD) region. Vertical O3 profiles below 5 km can be grouped into 5 categories: (1) peak mixing ratio type, (2) well-mixed type, (3) layered-structure type, (4) episodic pollution type and (5) alti- tudinal increasing type. Vertical distributions of O3 affected by regional transport of polluted air masses were investigated. Transport of polluted air from high latitudes of northern China, ac- companying subsiding motion of air and stagnant atmospheric conditions are important factors that lead to high mixing ratios of O3 at Lin’an. The stagnant atmospheric conditions associated with a continental high pressure system and pollution plume transported from the YRD and cen- tral-eastern China also lead to regional accumulation of O3 and high O3 mixing ratio at Lin’an. Long-range transport of O3 and pollutants from the Pearl River delta in South China and in-situ O3 formation also resulted in elevated O3 mixing ratios at around 1 km altitudes and layered O3 distribution in the lower troposphere.

关键词： vertical ozone distribution, lower troposphere, Yangtze River delta, Lin'an.

A preliminary study on sediment flux in the Changjiang delta during the postglacial period

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Science China Earth Sciences 2003年第7期46卷 743-752页

作者：李保华李从先沈焕庭 Key Laboratory of Marine Geology Ministry of Education of China Tongji University State Key Laboratory of Estuarine and Coastal Research East China Normal University

The sequence boundary and maximum flooding surface of the postglacial transgressive cycle in the Changjiang delta have been identified by 265 cores. Based on these data, the sediment amounts and the thickness-isopach maps of postglacial sedimentary cycle, transgressive and regressive successions in the Changjiang delta have been worked out. The results show that the sediment amounts of the postglacial cycle, transgressive succession and regressive succession are 17742.2×108 tons, 9791.9×108 tons and 7950.3×108 tons, respectively. The postglacial sediments deposited in the incised valley are more than those in the two flanks, and the sediments contained in the transgressive succession are more than those in the regressive succession. The postglacial sediments deposited in the southern flank are more than those in the northern flank, and the sediments in the area seaward from the postglacial transgression maximum (PTM) of each flank are more than those in the area landward from the PTM. Considering both the possible changes of the ratio between the sediment amount remained in the modern Changjiang delta and the sediment discharge of the Changjiang River in the postglacial period, and the changes of the sediment discharge, the authors believe that in the postglacial period, the sediment discharge of the Changjiang River is (2.36—4.86)×108 tons/a on average, totaling to (35400—70800)×108 tons, and the sediments delivered to sea and adjacent coasts are (1.18—3.54)×108 tons/a on average, totaling to (17700—53100)×108 tons.

关键词： postglacial transgressive cylce, the Changjiang River, the Changjiang delta, sediment flux, transgressive succession, regressive succession.

Characteristics of observed trace gaseous pollutants in the Yangtze delta

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Science China Earth Sciences 2003年第4期46卷 397-404页

作者：王会祥唐孝炎王木林颜鹏王韬邵可声曾立民杜惠芳陈立民 Center of Environmental Sciences and State Key Laboratory of Environmental Simulation and Pollution Control Peking University Chinese Academy of Meteorological Sciences Hong Kong Polytechnic University Hong Kong China Department of Environmental Science and Engineering Fudan University

Six stations in the Yangtze delta were set up to measure minute-average ground-level concentrations of NO, NOx, SO2, CO and O3 from May, 1999 to Oct., 2000 continually. The per-centage of total valid data of all sites was over 80%. The observed data were of adequate regional representation. The individual mean value of NO, NOx, SO2 and CO in the six selected sites was much higher than that of background level. Strong seasonal variations of observed data in the sites were expounded with peaks in winter. These showed that the air had been contaminated by anthropogenic pollutants. The highest monthly mixing ratios of O3 were found in May or June, and an ozone episode in September.

关键词： Yangtze delta, gaseous pollutants, tropospheric ozone.