A robust sample of submillimetre galaxies: constraints on the prevalence of dusty, high-redshift starbursts     

R. J. Ivison  Ian Smail  J. S. Dunlop  T. R. Greve  A. M. Swinbank  J. A. Stevens  A. M. J. Mortier  S. Serjeant  T. A. Targett  F. Bertoldi  A. W. Blain  S. C. Chapman 《Monthly notices of the Royal Astronomical Society》2005,364(3):1025-1040

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Reef exploration in the East Sengkang Basin,Sulawesi, Indonesia     

A.M. Grainge  K.G. Davies 《Marine and Petroleum Geology》1985,2(2):142-155

Reconnaissance seismic shot in 1971/72 showed a number of well defined seismic anomalies within the East Sengkang Basin which were interpreted as buried reefs. Subsequent fieldwork revealed that Upper Miocene reefs outcropped along the southern margin of the basin. A drilling programme in 1975 and 1976 proved the presence of shallow, gas-bearing, Upper Miocene reefs in the northern part of the basin. Seismic acquisition and drilling during 1981 confirmed the economic significance of these discoveries, with four separate accumulations containing about 750 × 10⁹ cubic feet of dry gas in place at an average depth of 700 m. Kampung Baru is the largest field and contains over half the total, both reservoir quality and gas deliverability are excellent. Deposition in the East Sengkang Basin probably started during the Early Miocene. A sequence of Lower Miocene mudstones and limestones unconformably overlies acoustic basement which consists of Eocene volcanics. During the tectonically active Middle Miocene, deposition was interrupted by two periods of deformation and erosion. Carbonate deposition became established in the Late Miocene with widespread development of platform limestones throughout the East Sengkang Basin. Thick pinnacle reef complexes developed in the areas where reef growth could keep pace with the relative rise in sea level. Most reef growth ceased at the end of the Miocene and subsequent renewed clastic sedimentation covered the irregular limestone surface. Late Pliocene regression culminated in the Holocene with erosion. The Walanae fault zone, part of a major regional sinistral strike-slip system, separates the East and West Sengkang Basins. Both normal and reverse faulting are inferred from seismic data and post Late Pliocene reverse faulting is seen in outcrop.  相似文献   

The O4f + O6V eclipsing binary system Sk−67°105 in the Large Magellanic Cloud     

Pablo G. Ostrov  Emilio Lapasset 《Monthly notices of the Royal Astronomical Society》2003,338(1):141-146

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Early warning research on salt-alkalization desertification in western Songnen Plain     

BIAN Jian-min  LIN Nian-feng  TANG Jie College of Environment  Resources  Jilin  University  Changchun  Jilin  China 《东北亚地学研究》2005,(Z1)

Desertification is an environmental issue in the world. The salt-alkalization desertification land area formed by both primary and secondary salt-alkalization has extended in a large scale, which has become a significant eco-environmental problem. Based on the characteristics of eco-environment and the situation of desertification in western Songnen plain, this paper reports the analyzes of its formation in background and cause. An early warning system on the salt-alkalization desertification is established and the GIS technology is used to abstract the information of desertification evaluation index. Supported by the integrated technology of the GIS and ANN, the orientation and quantitative result of desertification are gained, which is helpful to the eco-environment protection and resource development in western Songnen Plain.  相似文献   

Pregalactic Chemistry     

S. Lepp 《Astrophysics and Space Science》2003,285(3-4):737-744

The evolution of the universe from times after the recombination of the first atoms is controlled by chemistry. Chemistry can also help us to learn more about the first structures. In this paper we review the chemistry and atomic physics that are important in the time shortly after recombination, including the formation of the first structures. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Radiative association in Li+H revisited: the role of quasi-bound states     

O. J. Bennett  A. S. Dickinson  T. Leininger  F. X. Gadéa 《Monthly notices of the Royal Astronomical Society》2003,341(1):361-368

The role in radiative association of narrow resonances arising from quasi-bound levels is examined. For the rate coefficient the contribution from such levels is readily calculated in terms of the Einstein A -coefficient from bound rovibrational levels generated using a suitable alternative boundary condition. By locating systematically all the quasi-bound levels, an enhancement by more than an order of magnitude of the rate coefficient for Li(2s) + H(1s) association above about 600 K is obtained. The effect on the LiH abundance in the early Universe is no more than an increase of a factor of 3 for limited ranges of values of the redshift. For the Li(2p) state the effect of narrow resonances appears to have been taken into account in previous calculations.  相似文献   

Biostratigraphic and isotopic record of the Cenomanian–Turonian deposits in the Ohaba-Ponor section (SW Haţeg, Romania)     

Mihaela Carmen Melinte-Dobrinescu  Ana-Voica Bojar 《Cretaceous Research》2008,29(5-6):1024

The middle Cenomanian–lower Turonian deposits of Ohaba-Ponor section (Southern Carpathians) were studied from biostratigraphic and isotopic points of view. Both the qualitative and semiquantitative nannofloral analyses, as well as the stable isotope (δ¹³C and δ¹⁸O) data support significant palaeoenvironmental changes in the investigated interval. Two δ¹³C positive excursions were recognized: (1) an excursion up to 1.8‰ (PDB) within the middle/late Cenomanian boundary; (2) an excursion up to 2.2‰ (PDB) in the Cenomanian/Turonian boundary interval. The oldest δ¹³C positive excursion recorded (placed within the Acanthoceras jukes-brownei/Eucalycoceras pentagonum Ammonite Zone boundary interval, and in the NC11 Calcareous Nannofossil Zone respectively) could be assigned to the middle Cenomanian Event II (MCEII). During the above-mentioned event, significant increase in abundance of Watznaueria barnesae, followed by successive blooms of Biscutum constans and Eprolithus floralis, were observed. The youngest δ¹³C positive excursion was identified in the Cenomanian/Turonian boundary interval (in the NC12 and lower part of the NC13 Calcareous Nannofossil Zones). Even the amplitude of this δ¹³C positive excursion is lower in the Ohaba-Ponor section, as generally reported, this may represent the regional record of the OAE2. The successive peaks of the nannofossils Biscutum constans, Zeugrhabdotus erectus and Eprolithus floralis indicate episodes of cooler surface water and high fertility, which preceded and lasted the Cenomanian/Turonian boundary event. Additionally, fluctuations of δ¹⁸O values between −2 and −6‰ suggest also cooler conditions within the Cenomanian/Turonian boundary interval.  相似文献   

东营凹陷北部沙河街组四段深部储层多重成岩环境及演化模式   总被引：7，自引：0，他引：7       下载免费PDF全文

张善文  袁静  隋风贵  陈鑫 《地质科学》2008,43(3):576

主要通过薄片鉴定、扫描电镜观察、包裹体分析、粘土矿物分析、镜质体反射率测试和岩心物性分析等手段,结合构造发育史和有机质热演化史等研究成果,以揭示东营凹陷北带古近系深部碎屑岩储层成岩环境及演化模式为目的展开研究工作。结果表明:东营凹陷北带古近系深部碎屑岩储层存在酸性、碱性和酸性碱性交替等多重成岩环境。酸性成岩环境以碳酸盐矿物溶解、长石溶解蚀变为高岭石并伴生石英次生加大等为标志,碱性成岩环境以石英质颗粒及其次生加大边溶解、长石次生加大和晚期碳酸盐矿物沉淀为标志。研究区古近系深部碎屑岩储层成岩环境由浅至深大致经历了碱性—酸性—酸性碱性交替(局部碱性较强)—碱性—弱碱性的演化过程,并建立了沙河街组四段的成岩演化和储层改造模式。  相似文献   

甘肃庆城庄19井区上三叠统延长组长82亚油层组低渗透储层的地质特征     

谢渊  ;谢正温  ;孙虎  ;鲁洪江  ;刘国良 《中国区域地质》2008,(6):844-854

长82亚油层组是甘肃庆城地区庄19井区上三叠统延长组中储集砂岩相对富集的层位,但砂岩低渗透性的特点显著,成为影响该区石油储产量增长的主要地质因素。结合前人的相关工作,通过钻井岩心观察、测井曲线分析、储层岩石实验测试等工作,详细地分析了庄19井区长82亚油层组低渗透储层的地质特征,认为沉积微相和压实作用、胶结作用是控制低渗透性储集砂岩发育和分布的主要地质因素,寻找以水下分流河道微相为代表的有利储集相带砂岩体是油气勘探的重要方向。  相似文献   

贵州晴隆大厂晚二叠世初期河流相沉积特征——兼论与上下地层接触关系     

李明道 《贵州地质》2008,25(3)

晚二叠世初期,在晴隆大厂一带,以"大厂层"为基底的山间盆地中,形成了一条自北东流向南西的规模较大的曲流河。该河流微相发育,其沉积物包括河道砾岩、边滩砂屑岩和洪泛平原泥质岩等。这套沉积地层上与上二叠统峨眉山玄武岩下与"大厂层"或局部与中二叠统茅口组接触。此乃峨眉地幔隆起边缘的沉积效应。  相似文献