The Geologic Time Scale and the Italian stratigraphic record

The construction of the Geologic Time Scale (GTS) is a titanic scientific challenge that has been under way for two centuries and will require much dedicated effort in the future. Italy preserves a paramount stratigraphic record of Mesozoic and Cenozoic marine sediments that have been significant in the development of the modern GTS. The Italian stratigraphic record has been histori-cally important in introducing and defining the standard Chronostratigraphic Units (CUs) of the Neogene and Quaternary. Pelagic successions from Northern Apen-nines and Southern Alps have been used in the seventies for integrating the late Cretaceous-Paleogene Geomag-netic Polarity Time Scale (GPTS) with planktonic microfossil biostratieraohv and standard CUs. This was a major contribution to the construction of a new gener-ation of GTS based on integrated magnetobiochronol-ogy. The middle Miocene to early Pleistocene marinerecord from Sicily and southern Italy has been funda-mental for establishing the recently developed Astro-nomical Time Scale (ATS). In prospect, there are many potentials still to be exploited in the Italian marine stratigraphic record for implementing the GTS by defin-ing GSSPs of various CUs, improving magneto-biochronology and extending downwards the ATS.     

Sedimentary characteristics of tide-dominated estuary in Donghetang Formation（Upper Devonian）, central Tarim Basin

The Donghetang Formation （Upper Devonian） in central Tarim Basin has been thought an important oil and gas reservoir since the abundant oil and gas resources were found in the wells W16, W20, W34, and other fields. However, the sedimentary environment of the Donghetang Formation has been disputed because it suffered from both tidal and fluvial actions and there were not rich fossils in the sandstone. After the authors analyzed sedimentary features by means of drill cores, well logging data, paleosols, and with SEM obseruations, three kinds of sedimentary environments were distinguished： alluvial fan, tide-dominated estuary, and shelf. Particularly, the sedimentary features of tide-dominated estuary were studied in detail. Besides, the authors discussed sedimentary characteristics of the Donghetang Formation which was divided into two fourth-order sequences and five system tracts. At the same time, according to the forming process of five system tracts, the whole vertical evolution and lateral transition of tide-dominated estuary were illustrated clearly. Finally, the reservoir quality was evaluated based on porosity and permeability.     

海域层序地层学环境恢复技术

海域层序地层学环境恢复技术是针对我国区勘探初期的沉积盆地，充分利用已有的地质和地球物理资料，主要是二维地震资料，以层序地层学为指导，在层序分析、地震相和岩性预测的基础上，研究盆地发育的各沉积时期的沉积环境及沉积演化的地球物理资料地质解释技术，本文介绍了该技术的系统构成、技术特点和实现过程。     

地层学的发展推动油气地质理论研究的进步

自上个世纪50年代以来,地层学经历了彻底的变革,逐渐由“相模式”、“沉积体系”、“地震地层学”发展到目前的“层序地层学”,形成高分辨率层序地层学和事件地层学的理论体系和研究方法。文章围绕层序地层学、高分辨率层序地层学基本方法及理论体系,与含油气系统相关关系进行了讨论。     

舒曼海山铁锰结壳中钙质超微化石生物地层的年龄测定

用钙质超微生物地层学确定夏威夷考爱岛以北200英里，舒曼海山铁锰结壳内不同层次的年龄和生长速率．这项工作是利用不同地球化学指示物重现结壳古海洋历史研究的一部分．     

塔河地区志留纪层序地层划分及沉积相分析

塔河地区志留系缺失中、上统,只保留了下统柯坪塔格组及塔塔埃尔塔格组,发育滨海-浅海碎屑岩沉积,包括潮坪、陆棚等沉积亚相和中潮坪（混合坪）、低潮坪（砂坪）、陆棚泥等3个微相.该地区志留系分为3个三级层序,其中柯坪塔格组包括了SQ1、SQ2,塔塔埃尔塔格组为SQ3.构造运动和海平面升降是塔河地区志留系三级层序及其内部体系域形成的主要控制因素.     

从地层记录的特性论岩石地层学的困惑

地层记录有四个特性:不完整性、非渐变性、旋回性及复杂性。这四个特性在岩石地层中将形成两种穿时性——相界面穿时及间断面穿时,最终造成常规标志层的缺乏和复杂有序的相变。为此,根据"岩性、岩相的统一"来划分和对比岩石地层单位时,常常具有人为性及不确定性。在相序基础上识别出的旋回层序,具有空间上相序的有序性及时间上环境变化的同步性两大特征,在把它用于岩石地层学研究时,具有以下优点:1)不同级别旋回层序及其有序叠加形式的研究是从岩石地层记录的复杂性中寻找规律的最好方法;2)旋回层序,特别是长周期旋回层序的界面,同样可以作为岩石地层单位的界面;3)地层记录的旋回性的研究,可以丰富岩石地层单位的的内容,为其划分对比提供更多的天然标志。     

吉尔嘎朗图凹陷宝饶洼槽下白垩统层序地层与沉积体系

运用高分辨率层序地层学原理和方法,通过对钻井和地震资料的综合分析,在二连盆地吉尔嘎朗图凹陷下白垩统中识别出1个超长期基准面旋回(二级层序)SSC1和5个长期基准面旋回(三级层序):LSC1,LSC2,LSC3,LSC4,LSC5,分析了各旋回的发育特征。识别出五种类型的沉积体系:滨浅湖近岸水下扇、较深水湖浊积扇、滨浅湖扇三角洲、滨浅湖辫状河三角洲和河流沉积体系,并在等时地层格架内分析了各基准面旋回的沉积体系构成和储层砂体的发育情况。综合分析生、诸、盖条件后认为,在垂向上,LSC3旋回为本区最有利的储集层段,在平面上,本区的油气勘探应主要寻找宝饶构造带辫状河三角洲前缘砂体,主要储层砂体类型为前缘分流水道砂和前缘席状砂。