The middle pleistocene deposits of Waverley Wood Pit,Warwickshire, England     

F. W. Shotton  D. H. Keen  G. R. Coope  A. P. Currant  P. L. Gibbard  M. Aalto  S. M. Peglar  J. E. Robinson 《第四纪科学杂志》1993,8(4):293-325

A complex of channels underlying the Baginton-Lillington Gravel (Baginton Formation) at Waverley Wood Quarry, Warwickshire is described. Fossil pollen and plant macrofossils, Coleoptera, Ostracoda, Mollusca and Mammalia are described from the channel-fill deposits. Consideration of all the evidence allows the identification of four separate stages of channel fill which largely occurred under a cool temperate climate. At the top of Channel 2 evidence for a cold, continental climatic episode can be recognised, suggesting that the whole complex was deposited under a fluctuating climate at the end of a temperate stage. At two levels in the channels human artefacts were recovered confirming the presence of Palaeolithic people in Warwickshire during the deposition of the sediments. Amino-acid geochronology suggests an age within the ‘Cromerian Complex’ Stage for the channels. The small vertebrate and molluscan faunas indicate that the deposits are no older than the latter part of the ‘Cromerian Complex’ Stage of East Anglia. The regional stratigraphic significance of the Waverley Wood succession is outlined.  相似文献   

Prognosis of pool phase state and hydrocarbon fluid composition for the Pre-Caspian OGP     

O.L. Nechaeva  E.M. Graizer 《地学学报》1993,5(3):298-304

The results of detailed studies and interpretations are presented for composition variations, structural properties and the phase state of hydrocarbon fluids from subsalt pools of the Pre-Caspian depression. These data serve as a basis for substantiating the existence of several types of condensate, and identifying the locations of the main centres of fluid generation. The basic geological-geochemical conditions controlling the composition of condensate and free gases have been determined as well as their present phase state. A set of basic criteria is proposed as well as prognostic maps for the condensate and free gas composition, and the pool phase states.  相似文献   

Late Holocene relative sea level rise and the Neoglacial history of the Greenland ice sheet     

Antony J. Long  Sarah A. Woodroffe  Sue Dawson  David H. Roberts  Charlotte L. Bryant 《第四纪科学杂志》2009,24(4):345-359

In West Greenland, early and mid Holocene relative sea level (RSL) fall was replaced by late Holocene RSL rise during the Neoglacial, after 4–3 cal. ka BP (thousand calibrated years before present). Here we present the results of an isolation basin RSL study completed near to the coastal town of Sisimiut, in central West Greenland. RSL fell from 14 m above sea level at 5.7 cal. ka BP to reach a lowstand of ?4.0 m at 2.3–1.2 cal. ka BP, before rising by an equivalent amount to present. Differences in the timing and magnitude of the RSL lowstand between this and other sites in West and South Greenland record the varied interplay of local and non‐Greenland RSL processes, notably the reloading of the Earth's crust caused by a Neoglacial expansion of the Greenland Ice Sheet (GIS) and the subsidence associated with the collapse of the Laurentide Ice Sheet forebulge. This means that the timing of the sea level lowstand cannot be used to infer directly when the GIS advanced during the Neoglacial. The rise in Late Holocene RSL is contrary to recently reported bedrock uplift in the Sisimiut area, based on repeat GPS surveys. This indicates that a belt of peripheral subsidence around the current ice sheet margin was more extensive in the late Holocene, and that there has been a switch from subsidence to uplift at some point in the last thousand years or so. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   

Rapid Lateglacial tree population dynamics and ecosystem changes in the eastern Baltic region     

Maija Heikkilä  Sonia L. Fontana  Heikki Seppä 《第四纪科学杂志》2009,24(7):802-815

A growing body of evidence implies that the concept of 'treeless tundra' in eastern and northern Europe fails to explain the rapidity of Lateglacial and postglacial tree population dynamics of the region, yet the knowledge of the geographic locations and shifting of tree populations is fragmentary. Pollen, stomata and plant macrofossil stratigraphies from Lake Kurjanovas in the poorly studied eastern Baltic region provide improved knowledge of ranges of north‐eastern European trees during the Lateglacial and subsequent plant population responses to the abrupt climatic changes of the Lateglacial/Holocene transition. The results prove the Lateglacial presence of tree populations (Betula, Pinus and Picea) in the eastern Baltic region. Particularly relevant is the stomatal and plant macrofossil evidence showing the local presence of reproductive Picea populations during the Younger Dryas stadial at 12 900–11 700 cal. a BP, occurring along with Dryas octopetala and arctic herbs, indicating semi‐open vegetation. The spread of Pinus–Betula forest at ca. 14 400 cal. a BP, the rise of Picea at ca. 12 800 cal. a BP and the re‐establishment of Pinus–Betula forest at ca. 11 700 cal. a BP within a span of centuries further suggest strikingly rapid, climate‐driven ecosystem changes rather than gradual plant succession on a newly deglaciated land. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   

Galaxy merging, the fundamental plane of elliptical galaxies and the  M_BH−σ₀  relation     

C. Nipoti  P. Londrillo  L. Ciotti 《Monthly notices of the Royal Astronomical Society》2003,342(2):501-512

  相似文献   

Technique for Controlling Spread of Limnotic Oncomelania   总被引：1，自引：0，他引：1  

李大美  王祥三  LAI Yonggen 《中国海洋湖沼学报》2003,21(3):251-260

Schistosomiasis is a parasitic disease mostly found in areas along the Changjiang River of China. The disease is spread solely through an intermediary named oncomelania, so its spread of schistosomiasis can be controlled by properly designing water intakes which prevent oncomelania from entering farming land or residential areas. This paper reports a successful design process and a new oncomelania-free intake device. The design of the new intake is based on a sound research program in which extensive experimental studies were carried out to gain knowledge of oncomelania eco-hydraulic behavior and detailed flow field information through CFD simulation.  相似文献   

Optical and near-infrared observations of the microquasar V4641 Sgr during the 1999 September outburst     

S. Chaty  P. A. Charles  J. Martí  I. F. Mirabel  L. F. Rodríguez  T. Shahbaz 《Monthly notices of the Royal Astronomical Society》2003,343(1):169-174

  相似文献   

Dwarf galaxies in Clusters     

L. Infante  S. Mieske  M. Hilker 《Astrophysics and Space Science》2003,285(1):87-96

The equilibrium of a self gravitating cylindrical polytrope with a general magnetic field and rotation has been discussed. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Computer Simulation of Sputtering of Lunar Regolith by Solar Wind Protons: Contribution to Change of Surface Composition and to Hydrogen Flux at the Lunar Poles     

Starukhina  L. V. 《Solar System Research》2003,37(1):36-50

A computer simulation of the sputtering of lunar soil by solar wind protons was performed with the TRIM program. The rate of the sputtering-induced erosion of regolith particles was shown to be less than 0.2 Å per year. A preferential sputtering of Ca, Mg, and O was found along with a less intense sputtering of Fe, Si, and Ti. However, with no other selection mechanisms, surface concentrations of the atoms would differ from the volume ones by no more than 6 %. The enrichment of rims of regolith particles with iron occurs as a result of selective removal of lighter atoms from the lunar surface because of different energies of escape from the Moon's gravity. The energy distributions proved to be the same for all sorts of the sputtered atoms, except for implanted hydrogen; thus, a greater fraction of the atoms left on the lunar surface corresponds to heavier elements. According to simulation results, the concentration of reduced iron observed in the mature regolith could be attained during the time of regolith particle exposure to the present flux of solar wind (10⁵ years). Thus, sputtering can provide the concentration of Fe₀ observed in regolith. On periphery of a cloud of impact vapor the temperature is too low for an irreversible selective removal of evaporation products; thus, a meteoritic bombardment contributes to the formation of composition of the rims of regolith particles mainly through enrichment of the rims with elements from the bulk of the particles. The estimates of fluxes of backscattered solar wind protons and of sputtered protons, earlier implanted to the regolith, demonstrated that their contribution to the proton flux near the poles is only 10⁴ cm^–2 s^–1. This is by two orders of magnitude smaller than the proton flux from the Earth's magnetosphere which is, therefore, the main source of protons for permanently shaded polar craters of the Moon.  相似文献   

Late Quaternary vegetation changes around Lake Rutundu,Mount Kenya,East Africa: evidence from grass cuticles,pollen and stable carbon isotopes     

Dr M. J. Wooller  D. L. Swain  K. J. Ficken  A. D. Q. Agnew  F. A. Street-Perrott  G. Eglinton 《第四纪科学杂志》2003,18(1):3-15

Woody, subalpine shrubs and grasses currently surround Lake Rutundu, Mount Kenya. Multiple proxies, including carbon isotopes, pollen and grass cuticles, from a 755‐cm‐long core were used to reconstruct the vegetation over the past 38 300 calendar years. Stable carbon‐isotope ratios of total organic carbon and terrestrial biomarkers from the lake sediments imply that the proportion of terrestrial plants using the C₄ photosynthetic pathway was greater during the Late Pleistocene than in the Holocene. Pollen data show that grasses were a major constituent of the vegetation throughout the Late Pleistocene and Holocene. The proportion of grass pollen relative to the pollen from other plants was greatest at the last glacial maximum (LGM). Grass cuticles confirm evidence that C₄ grass taxa were present at the LGM and that the majority followed the cold‐tolerant NADP‐MEC₄ subpathway. Copyright © 2003 John Wiley & Sons, Ltd.  相似文献