The Bengal Fan: Some preliminary results from ODP drilling

Three deep holes, with a maximum penetration of 960 m below sea floor, were drilled into the distal Bengal Fan just south of the equator during ODP Leg 116. The entire section recovered is dominated by sandy silt and mud turbidites derived from the Ganges Delta and from the continental margin of the western Bay of Bengal, interbedded with thin pelagic clays and with biogenic turbidites probably from a local sea mount source. The effects of Hi-Malayan uplift, sea level fluctuations, local tectonics, and fan channel/lobe processes have closely interacted to produce the observed sedimentary record of the past 17 million years since the early Miocene.Coauthors include: James R. Cochran, Lamont-Doherty Geological Observatory (Co-chief scientist); Dorrik A. V. Stow, Nottingham University, England (Co-chief scientist); Christian A. Auroux, Texas A & M University, USA (ODP staff scientist); Kazou Amano, Ibaraki University, Japan; Peter S. Balson, British Geological Survey, Keyworth, Notts, England; Jacques Boulegue, Pierre & Marie Curie University, Paris, France; Garrett W. Brass, University of Miami, Florida, USA; Jeffrey Corrigan, University of Texas, Austin, USA; Stefan Gartner, Texas A & M University, USA; Stuart A. Hall, University of Houston, Texas, USA; Silvia Iaccarino, University of Parma, Italy; Toshio Ishizuka, University of Tokyo, Japan; trena Kacmarska, Mount Allison University, New Brunswick, Canada; Heidemarie Kassens, Kiel University, West Germany; Gregory Leger, Dalhousie University, Halifax, Nova Scotia, Canada; Franca Proto Decima, University of Padova, Italy; C. V. Raman, Andhra University, Visakhapatnam, India; William W. Sager, Texas A & M University, USA; Kozo Takahashi, Woods Hole Oceanographic Institution, USA; Thomas Thompson, 580 Euclid Ave, Boulder, Colo, USA; Jean-Jacques Tiercelin, University of Bretagne, Brest, France; Mark Townsend, University of Nottingham, England; Andreas Wetzel, Tubingen University, West Germany; N. P. Wijayananda, National Aquatatic Resource Agency, Colombo, Sri Lanka; and Colin Williams, Lamont-Doherty Geological Observatory.     

Submersible structural study of Tamayo transform fault: East Pacific Rise, 23°N (project RITA)

A submersible structural study of Tamayo transform fault, the second field study of an oceanic transform, was conducted with the diving saucer CYANA as part of the international project RITA. On the basis of the surface ship surveys and deep-tow traverses made prior to the diving program, the four successful dives of CYANA established the geometry of the presently active shear zones and demonstrated that the median ridge of the Tamayo transform is tectonically inactive. The dive results require the presence, in an area marked by diapir-like bodies, of an extensional relay zone linking the two offset shear zones which trend about 110°.P. CHOUKROUNE, Laboratoire de Géologie structurale, Université de Rennes I, avenue du Général-Leclerc, 35042-Rennes Cédex, France; P. J. FOX, State University of New York at Alban, Albany, New York, 12222, USA; M. SEGURET, Laboratoire de Géologie structurale Université des Sciences et Techniques du Languedoc, Place Eugéne-Bataillon, 34060, Montpellier Cédex, France; J. FRANCHETEAU, H. D. NEEDHAM, Centre Océanologique de Bretagne, B. P. 337, 29273, Brest Cédex, France; T. JUTEAU, Laboratoire de Minéralogie-Pétrographie, Université Louis-Pasteur, 1 rue Blessig, 67084, Strasbourg, Cédex, France; R. D. BALLARD, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts, 02543, USA; W. NORMARK, United States Geological Survey, Pacific-Arctic Branch of Marine Geology, Menlo Park, California, 94025, USA; A. CARRANZA, Centro de Ciencias del Mar y Limnologia, Ciudad Universitaria, Mexico 20 DF, Mexico; D. CORDOBA, J. GUERRERO, Instituto de Geologia, UNAM, Ciudad Universitaria, Mexico 20 DF Mexico; C. RANGIN, UNAM,now at Université de Paris VI, France.     

Sedimentary Features of Shallow Ancient River Channels on the Northern Shelf of the South China Sea

Quaternary buried ancient river channels are widespread in the shallow-level sediments of the northern shelf of the South China Sea. The sedimentary sequence mainly of fluvial deposits comprise an important component part of the low-stand system tract and transgressive system tract in the study region. The plannar variation and spatial association of the sedimentary features such as incised valley fillings, deltaic foreset wedges and block slides of shelf-marginal fans reflect the palaeogeographic environment during the fall of the regional sea level in the northern part of the South China Sea. Based on the high-resolution seismic reflection data and gelogical data from boreholes, the present paper makes an integrated interpretation of the Quaternary ancient river channels in the shallow sediments of the study area, studies the sedimentary features of the ancient channels such as their spatial distribution, seismic facies reflection indicators, sedimentary facies and sand -body types, and discusses thei     

从江县翁浪金矿床容矿岩石与围岩蚀变及其找矿标志

文章简单介绍了构造蚀变岩型金矿翁浪金矿床的容矿岩石和围岩蚀变特征，指出该类矿床的找矿标志，对进一步寻找此类矿床有一定的意义。     

平湖油气田凝析油回注油藏对开发效果影响机理研究

凝析油回注油藏是平湖油气田开发过程中为应对海底输油管线而采取的一种工程应急措施。凝析油回注油藏会引起油层内流体渗流特征的变化，并进而影响油井恢复生产后的开发指标。从室内物理模拟实验和油藏数值模拟两方面开展凝析油回注油藏的影响效果分析，并根据研究结果提出合理的回注方式，不仅从机理上为解决海上油气田开发工程中所遇类似突发事件的处理提供了依据，而且在物理模拟实验和油藏数值模拟研究相结合对油藏基础研究方面提供一些重要的结论。     

磁共振用于医学成像与地面找水方法的技术对比研究

目的 医学核磁共振与地面核磁共振找水是核磁共振技术应用的不同领域。本文通过对二者在方法原理、技术、应用等方面的对比研究，提出了地面核磁共振找水工作建议。     

山东东营凹陷渐新统东营组的天文地层研究

选定东营凹陷牛38、郝科1和利1等3口井东营组进行天文地层研究。以牛38井沙河街组一段顶界31.8Ma作为东营组底界年龄,得到3口井各段的年龄平均值为:东二段底28.406Ma,东一段底25.385Ma和顶界24.467Ma。东营组底界(31.829Ma)大致相当于"中国区域地层表"提出的32Ma的渐新统底年龄,但是与"国际地层表"提出的渐新世鲁培尔阶底界(33.9Ma)相差1.9Myr。东三段底界、顶界的平均年龄分别为31.829Ma、28.406Ma大致可与中国的乌兰布拉格阶或国际的鲁培尔阶中上部相当;东二段底界至东一段顶界的平均年龄大致相当于塔本布鲁克阶或夏特阶。根据东营组岩石地层与天文地层研究认为,在三角洲沉积过程中,东营组各段界线是穿时的,如东三与东二段界线的年龄相差可达1.4Myr。根据偏心率理论曲线和小波分析,夏特阶底界(28.4Ma)附近的变化可能与偏心率100ka左右理论周期的特殊变化有关。     

东营凹陷古近系层序地层对成岩规律的控制作用

东营凹陷古近系发育了沙四段底界面(T7)、沙四段与沙三段分界面(T’6)及沙二下亚段顶界面(T’2)等3个二级层序界面。根据对储集层成岩作用的深入研究发现,原有的埋藏成岩作用序列不仅受深度的影响,而且受此层序地层所控制,在层序界面附近和层序体内部存在一定的规律性。据此确定了层序界面附近发育的淋滤、溶解成岩相带和层序体内部发育的黏土矿物转换和化学胶结成岩相带。认识到层序界面通常是流体运移的通道,影响界面上下低水位体系域和高水位体系域内储集层的成岩相展布,对改善储集层储集性能有利;层序体内部储集层成岩差异性明显,储集性往往受到制约。     

浅析宁芜北段铜矿地质特征、找矿前景与方向

在综合分析区域地质背景、铜矿床基本特征、主要控矿因素、找矿标志的前提下,对该区寻找铜矿的前景提出了看法,指出宁芜北段今后寻找铜矿应侧重斑岩型铜矿,提出了皇姑山等地区可作为今后寻找铜矿的重点地段及今后找矿的工作建议。