水窖沉沙池结构形式试验设计

通过对单厢式矩形断面、单厢式梯形断面、迷宫式、旋流式等 4种结构形成的沉沙池沉沙效率对比试验表明 ,以迷宫式沉沙池效果最佳 ,平均沉沙效率可达 88.3%。此种结构形式的断面尺寸为 1m、宽 0 .4m ,迷宫室底部比集水渠低 0 .2 m,迷宫分成 5个小厢室 ,每个厢室长 0 .146 m,沉沙池首部的静水池深 0 .2 5 m

Diversity, abundance and distribution of amoA-encoding archaea in deep-sea methane seep sediments of the Okhotsk Sea

The authors would like to thank Jin Sun, Jian Sun, Liangliang Kong, Nianshuang Wang, Chunhui Wang, Linbao Zhang and Ying Zhang for their assistance in the project. This work was supported by China Ocean Mineral Resources R&D Association grants DYXM-115-02-2-20 and DYXM-115-02-2-6, Hi-Tech Research and Development Program of China grant 2007AA091903, China National Natural Science Foundation grant 40576069, National Basic Research Program of China grant 2009CB219506 and the Fundamental Research Funds for the Central Universities of China grant 09CX05005A. M. G. K. was funded by incentive funds provided by the UofL-EVPR office and the US National Science Foundation (EF-0412129).

Impacts of anthropogenic activity on the recent evolution of the Huanghe (Yellow) River delta

Hydrological statistical data, remote sensing images, and bathymetric charts were used to study the recent evolution of the Huanghe (Yellow) River delta under human-induced interventions. It was clear that water and sediment discharge from the Huanghe River had dropped rapidly since 1970, particularly after 1986. The water and sediment discharges for the period of 1986-2000 were found to have been reduced to only 29.2% and 31.2% of those in the period of 1950-69. This was caused by human factors in the upper and middle reaches of the Huanghe River, including water diversion, damming and reservoir construction, and water and soil conservation. Based on the results from visual interpretation of processed Landsat (MSS or TMJETM+) images dated from 1976 to 2001 and two digital elevation models generated from bathymetric charts surveyed in 1976 and 1992, we found that human-induced reduction of water and sediment discharge led to coastline retrogradation, with the maximum mean recession rate of -0.51 km yr-1 over the period of 1976-98, and seabed erosion beyond the -20 m isobath between 1976 and 1992. Other impacts of human activities on the recent evolution of the Huanghe River delta, including tidal flats shrinking, artificial coastline increasing, land surface sinking and so on, were also analyzed. We found that: (i) the whole delta, including subaerial and subaqueous, has turned from a highly constructive period to a destructive phase; (ii) channelization and dredging were two of the main causes of delta destruction; (iii) land loss in the Huanghe River delta caused by submersion will be increased in the near future; (iv) the Huanghe River delta was becoming more fragile and susceptible to natural hazards.

Vertical transferring process of rare elements in coral reef lagoons of Nansha Islands, South China Sea

The vertical fluxes and vertical transferring forms of 18 rare elements were studied for the first time in the coral reef ecosystem of Nansha Islands, South China Sea, by deploying sediment traps, The results showed that the vertical transferring flux of most of the measured rare elements in Yongshu lagoon were higher than that in Zhubi lagoon. The vertical transferring forms of rare elements were mainly in the carbonate form, but Ta, As, Th mainly in the ion-exchange form, Ag in iron-manganese oxide form and Sb in the organic matter + sulphide form. None of the 18 rare elements was transferred mainly in the form of detritus silicate to sea floor. This proved that rare elements originating from the earth's crust were redistributed in sinking particulates after they were brought into ocean. The relation between the fluxes and surface seawater temperature (STT) was also studied. The sensitivity of rare elements to SST was in order: Rb>V>As>Ti>U>Zn>Sb>Hf>Ag>Cs.

中国华北和美国加州地区地震层析成像研究

In recent years seismic tomography has become a powerful tool for studying the three-dimensional crust and mantle structure. In this study, we collected a large number of regional and teleseismic travel-time data and used seismic tomography method to study the relationship between earthquake occurrence and crustal heterogeneity for the 1992 Landers earthquake, heterogeneity and evolution of lithosphere under North China Craton and Southern California, and deep structure and origin of the Changbai intraplate volcano in Northeast China. Our results show a correlation between the seismic rupture zone and crustal heterogeneity. The distribution of the Landers aftershocks is cluster-like and separated or terminated in areas where low-velocity anomalies exist．Most of the large earthquakes with magnitudes >4.0 occurred in or around areas with high P-wave velocity．The possibility is that high-velocity areas are brittle and strong parts which can sustain seismogenic stress，and so can generate earthquakes. Our tomographic images show a very heterogeneous structure in the crust and upper mantle beneath Southern California. Three major anomalies in the upper mantle are revealed clearly beneath the southern Sierra Nevada, Transverse Ranges and Salton Trough. We consider that the high-velocity anomaly beneath the Transverse Ranges was formed through asymmetrical two-side convergence of subcrustal lithosphere and sinking to asthenosphere. Formation of the dense crust root and “drip structure” caused the high-velocity anomaly under the southern Sierra Nevada. The Salton Trough low is the response to the lithospheric extension when the Pacific plate was rifted away from the North American Plate. The tomograpic images beneath the North China Craton show that there exist different lithospheric structures under the different blocks. Complex, prominent low-velocity and high-velocity anomalies are imaged beneath the North China Basin, Trans-North China Orogen (TNCO), and Ordos Block which correspond to rifted, orogenic and cratonic lithospheres, respectively. The thickness of the three-type lithospheres is about 70, 90 and >250 km, respectively. Our results suggest that lithospheric thinning under the eastern part of North China Craton is due to long-term replacement and chemical and thermal erosion of the ancient lithosphere by the hot asthenosphere. The remains of ancient lithosphere exist either in the present upper mantle or have sunk into the mantle transition zone. Our tomographic result of the Changbai volcanic area suggests that the origin of the Changbai volcano is related to the deep dehydration of the subducted Pacific slab and corner flow in the big mantle wedge (BMW) above the stagnant Pacific slab.

陡坡带砂砾岩体油气成藏模式研究——以东营凹陷西北部陡坡带为例

Based on the study of sequence stratigraphy, modern sedimentary, basin analysis, and petroleum system in abrupt slop of depression, this paper builds sedimentary system and model, sandy bodies distribution, and pool-forming mechanism of subtle trap. There are some conclusions and views as follows. By a lot of well logging and seismic analysis, the author founded up the sequence stratigraphic of the abrupt slope, systematically illustrated the abrupt slope constructive framework, and pointed out that there was a special characteristics which was that south-north could be divided to several fault block and east-west could be carved up groove and the bridge in studying area. Based all these, the author divided the studying area to 3 fault block zone in which because of the groove became the basement rock channel down which ancient rivers breathed into the lake, the alluvial fan or fan delta were formed. In the paper, the author illustrated the depositional system and depositional model of abrupt slope zone, and distinguished 16 kinds of lithofacies and 3 kinds of depositional systems which were the alluvial fan and fan-delta system, lake system and the turbidite fan or turbidity current deposition. It is first time to expound completely the genetic pattern and distributing rule of the abrupt slope sandy-conglomeratic fan bodies. The abrupt slope sandy-conglomeratic fan bodies distribute around the heaves showing itself circularity shape. In studying area, the sandy-conglomeratic fan bodies mainly distribute up the southern slope of Binxian heave and Chenjiazhuang heave. There mainly are these sandy-conglomeratic fan body colony which distributes at a wide rage including the alluvial fan, sub-water fluvial and the turbidite fan or the other turbidity current deposition in the I fault block of the Wangzhuang area. In the II fault block there are fan-delta front and sub-water fluvial. And in the Binnan area, there mainly are those the alluvial fan (down the basement rock channel) and the sandy-conglomeratic fan body which formed as narrowband sub-water fluvial (the position of bridge of a nose) in the I fault block, the fan-delta front sandy-conglomeratic fan body in the H fault block and the fan-delta front and the turbidity current deposition sandy-conglomeratic fan body in the m fault block. Based on the reservoir outstanding characteristics of complex classic composition and the low texture maturity, the author comparted the reservoir micro-structure of the Sha-III and Sha-IV member to 4 types including the viscous crude cementation type, the pad cementation type, the calcite pore-funds type and the complex filling type, and hereby synthetically evaluated 4 types sandy- conglomeratic fan body reservoir. In the west-north abrupt slope zone of Dongying Depression, the crude oil source is belonging to the Sha-III and Sha-IV member, the deep oil of Lijin oilfield respectively come from the Sha-III and Sha-IV member, which belongs to the autogeny and original deposition type; and the more crude oil producing by Sha-IV member was migrated to the Wangzhuan area and Zhengjia area. The crude oil of Binnan oil-field and Shanjiasi oil-field belongs to mixed genetic. It is the first time to illustrate systematically the genetic of the viscous crude that largely being in the studying area, which are that the dissipation of the light component after pool-forming, the biological gradation action and the bath-oxidation action, these oil accumulation belonging to the secondary viscous crude accumulation. It is also the first time to compart the studying area to 5 pool-forming dynamical system that have the characteristic including the common pressure and abnormal pressure system, the self-fountain and other-fountain system and the closing and half-closing system etc. The 5 dynamical systems reciprocally interconnected via the disappearance or merger of the Ethology and the fluid pressure compartment zone, the fault and the unconformity surface, hereby formed duplicated pattern oil-gas collecting zone. Three oil-gas pool-forming pattern were founded, which included the self-fountain side-direction migrated collecting pattern, the self-fountain side-direction ladder-shape pool-forming pattern and the other-fountain pressure releasing zone migrated collecting pattern. A series of systemic sandy-conglomeratic fan bodies oil-gas predicting theory and method was founded, based on the groove-fan corresponding relation to confirm the favorable aim area, according as the characteristic of seismic-facies to identify qualitatively the sandy-conglomeratic fan bodies or its scale, used the temporal and frequency analysis technique to score the interior structure of the sandy- conglomeratic fan bodies, applied for coherent-data system analysis technology to describe the boundary of the sandy-conglomeratic fan bodies, and utilized the well logging restriction inversion technique to trace quantificational and forecast the sandy-conglomeratic fan bodies. Applied this technique, totally 15 beneficial sandy-conglomeratic fan bodies were predicted, in studying area the exploration was preferably guided, and the larger economic benefit and social benefit was acquired.