地幔柱构造对松辽盆地及渤海湾盆地形成的制约

中国东部松辽盆地和渤海湾盆地形成与演化的深部动力学机制尚未得到很好的解释．通过对区域地震资料盆地沉积记录、火山岩岩石探针和大地构造演化历史的综合分析,认为地幔柱(柱头直径约500km)在晚侏罗世一晚白垩世时形成于松辽地区,经历了软流圈地幔上涌、地壳抬升与伸展、火山活动,导致松辽盆地的形成;由于华北板块向北移动,始新世时地幔柱(柱头直径600-800km)移动到京津一渤海湾地区,类似的地质过程形成了渤海湾盆地．渤海湾地幔柱的活动还可能是京津唐地区地震多发的根本原因。     

Paired Measurements of Foraminiferal δ~ (18) O and Mg/Ca Ratios of Indian Monsoons Reconstructed from Holocene to Last Glacial Record

The effect of seasonally reversing monsoons in the northern Indian Ocean is to impart significant changes in surface salinity(SS).Here,we report SS changes during the last 32 kyr in the Lakshadweep Sea(southeastern Arabian Sea)estimated from paired measurements of δ~(18)O and sea surface temperature(SST)using Globigerinoides sacculifer,an upper mixed layer dwelling foraminifera.The heaviest δ~(18)O_(G.sacculifer)(-0.07±0.08‰)is recorded between 23 and 15 ka,which could be defined as the last glacial maxi...     

The WASP Project and SuperWASP Camera

The WASP project and infrastructure supporting the SuperWASP Facility are described. As the instrument, reduction pipeline and archive system are now fully operative we expect the system to have a major impact in the discovery of bright exo-planet candidates as well in more general variable star projects.     

Progress on Nonlinear-Wave-Forced Sediment Transport Simulation

In this paper, we report on the use of a numerical wave tank (NWT), based on fully nonlinear potential flow (FNPF) equations, in driving simulations of flow and sediment transport around partially buried obstacles. The suspended sediment transport is modeled in the near-field in a Navier-Stokes (NS) model using an immersed-boundary method and an attached sediment transport simulation module. Turbulence is represented by large eddy simulation (LES). The NWT is based on a higher order boundary element method (BEM), with an explicit second-order time stepping. Hence, only the NWT boundary is discretized. The solution for the velocity potential and its derivatives along the boundary is obtained in the BEM, which subsequently provides a solution at any required internal point within the domain. At initial time, the NS-LES model domain is initialized with the 3-D velocity field provided by the NWT and driven for later time by the pressure gradient field obtained in the NWT. Incident wave fields, as specified in the NWT to drive sediment transport, can be arbitrary. Applications are presented here for single frequency waves, such as produced by a harmonic piston wavemaker in the laboratory, and modulated frequency wave groups. The feasibility of coupling the irrotational flow and NS solutions is demonstrated.     

Holocene environmental change in the West African Sahel: sedimentological and mineral‐magnetic analyses of lake sediments from Jikariya Lake,northeastern Nigeria

Previous studies have demonstrated long‐term changes in effective moisture in sub‐Saharan Africa. Here, we reconstruct Holocene environments using a ～7 m lake‐sediment sequence recovered from the northeastern Nigerian Sahel and attempt to distinguish basin‐specific changes from regional climatic variations. The sequence was analysed for sedimentological properties, mineral magnetism and pollen, and dated by ¹³⁷Cs, ²¹⁰Pb excess and ¹⁴C. Extremely arid conditions of the terminal Pleistocene ended ca. 11 500 cal. BP (calendar years) when climate ameliorated and a lake developed until the occurrence of an arid event leading to lake desiccation at ～11 200 cal. BP. Following this, climate ameliorated and a water body re‐emerged. Very wet conditions predominated 11 200–5600 cal. BP, followed by drought between 5600 and 5500 cal. BP and a return to moderate humidity from 5500 to 4000 cal. BP. After 4000 cal. BP, a marked deterioration occurred, culminating in lake desiccation at ca. 800 cal. BP. After this time the climate remained generally dry and the re‐emerging lake was shallow. Comparison of these results with other well‐dated sequences in the region demonstrates the importance of basin‐specific influences on the palaeolimnological records in addition to regional climatic controls. Disentangling these different controls, as well as the reconstruction of Holocene climate, therefore requires a multiple‐basin approach. Copyright © 2008 John Wiley & Sons, Ltd.     

Soil classifications for estimating site-dependent response spectra and seismic coefficients for building code provisions in western Kentucky

One hundred thirty-four horizontally polarized shear-wave (SH) seismic soundings have been performed in the Jackson Purchase Region of western Kentucky. These data have been used to derive the thicknesses and shear-wave velocities for the various impedance horizons in the upper 30 m of the soil column at each site for the purposes of general land-use management and loss estimation in the event of an earthquake. A generalized seismic susceptibility soil classification scheme adopted by the Borcherdt (1994a,b) was fit to the results. Soils across western Kentucky were found to be either SC-II or SC-III soils, correlating to gravelly soils having soft to firm consistency and stiff clays to loose/dense sands, respectively.     

Borate Deposits in Liaoning and Jilin Provinces, NE China: A Guide to Identifying Paleoproterozoic Collision Settings

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Work schedules on lowland farms in southern New Zealand from the late colonial period to the 1930s

Details of two‐way flows of primary products, implements, labour, information and finance drawn from runs of farm diaries, stock and station agents’ records, and newspaper articles were used to analyse work schedules on three comparable properties between 1874 and 1930, and to track the development of mixed cropping and livestock farming in southern New Zealand when draught horses were giving way to either steam or internal combustion engines as the prime source of motive power. The earliest records are for two farms in the late 19th century, and the most recent are for a third property in the 1920s.