地震沉积学在近岸水下扇沉积体系分析中的应用以泌阳凹陷东南部古近系核三上亚段为例

泌阳凹陷东南部受盆地边界断层控制,主要沉积平氏、栗园两套近岸水下扇复合体。为解决砂砾岩体分布预测的难题,本次研究在建立泌阳凹陷东南部陡坡带核三上亚段高频层序地层格架的基础上,运用地震沉积学的技术,进行相位转换、分频处理、地层切片,分析研究区古近纪核桃园组上亚段4个四级层序(从上到下SQH31-SQH34)内,近岸水下扇复合沉积体系的砂体展布特征,并与钻井资料相结合,建立了研究区核三上亚段的沉积相模式。研究表明核三上亚段沉积早期,断裂活动强度大,SQH34-SQH33内扇体展布面积较大,核三上亚段沉积晚期SQH32-SQH31,扇体横向展布相对稳定。其中,中扇亚相的辫状水道砂体,以及扇体前端的滑塌浊积体是油气勘探的主要目标。     

Cold-water coral banks and submarine landslides: a review

This paper aims to review the relation between cold-water coral bank development and submarine landslides. Both are common features on continental margins, but so far it has not been reviewed which effect—if at all—they may have upon each other. Indirect and direct relations between coral banks and landslides are evaluated here, based on four case studies: the Magellan Mound Province in the Porcupine Seabight, where fossil coral banks appear partly on top of a buried slide deposit; the Sula Ridge Reef Complex and the Storegga landslide both off mid-Norway; and the Mauritania coral bank province, associated with the Mauritanian Slide Complex. For each of these locations, positive and negative relationships between both features are discussed, based on available datasets. Locally submarine landslides might directly favour coral bank development by creating substratum where corals can settle on, enhancing turbulence due to abrupt seabed morphological variations and, in some cases, causing fluid seepage. In turn, some of these processes may contribute to increased food availability and lower sedimentation rates. Landslides can also affect coral bank development by direct erosion of the coral banks, and by the instantaneous increase of turbidity, which may smother the corals. On the other hand, coral banks might have a stabilising function and delay or stop the headwall retrogradation of submarine landslides. Although local relationships can be deduced from these case studies, no general and direct relationship exists between submarine landslides and cold-water coral banks.     

The Jurassic – Tertiary unconformity: A new exploration target for supergene-enriched iron oxide copper-gold –style mineralization in the Humboldt mafic complex,Nevada, USA

A Late Cretaceous to Early Oligocene episode of paleoweathering and supergene activity has been identified within the Jurassic-age (170 Ma) Humboldt mafic complex (HMC) and associated Boyer Ranch Formation of west-central Nevada, USA. This episode is responsible for significant subaerial weathering, erosion, oxidation and most importantly local supergene metal enrichment which could potentially have a major economic impact upon iron oxide copper-gold (IOCG)-style mineralization within the complex and in the Boyer Ranch Formation. Paleoweathering profiles that developed on the exposed Jurassic surface during this time now mark an angular unconformity (J-T unconformity) with a stratigraphically overlying, Tertiary (Oligocene) rhyolitic volcanic-volcaniclastic sequence.Differential uplift of the Jurassic surface is a direct result of the Middle and/or Late Jurassic Luning-Fencemaker compressional overthrust faulting event during which the entire complex was tectonically transported to its present location. The uplifted Jurassic paleosurface experienced one or more cycles of weathering, erosion, depression of the water table and uninterrupted supergene activity beginning at the end of the Cretaceous and possibly accelerating during the Paleocene-Eocene Thermal Maximum Event (∼56 Ma). Geochemically mature supergene Cu-oxide profiles developed over exhumed mineralized sections in terrains with favorable fault block movements. These paloweathering systems evolved from moderately acidic pH to near-neutral or slightly alkaline pH environments over time. High protolith reactivity and low hypogene pyrite concentrations modified acidity of supergene fluids thus limiting Cu mobility.Profiles that survived erosion were later buried and preserved by the Oligocene-age rhyolitic volcanic-volcaniclastic sequence before the onset of mid-Tertiary Basin and Range normal faulting. Subsequent partial unroofing of overlying Tertiary volcanic cover resulted in further erosion of some profiles. Erosional remnants mapped in the field include all or some components of the original supergene Cu-oxide profiles. Drilling results suggest profiles that remain buried are generally intact.Although this field-oriented study is considered preliminary, it concludes that known Jurassic-age IOCG-style mineral occurrences in the central HMC have been subjected to prolonged subaerial paleoweathering and supergene activity that has not been previously recognized. Where complete or nearly complete profiles are preserved, efficient cumulative Cu-enrichment to potentially ore grades has been documented in well defined oxide zones. These findings can be extrapolated to the entire J-T unconformity along which concealed and enriched deposits may exist. As such, the unconformity is considered a prime exploration target that is highly prospective for new discoveries of economically viable, supergene-enriched IOCG resources.     

基于地震正演与井震结合的低序级断层描述技术及应用

复杂断块油藏的开发实践表明,低序级断层控油作用明显,对低序级断层的精细刻画是研究不同类型断块油藏开发技术的基础和关键。随着开发程度的提高,断块油藏面临越来越复杂的地质条件,如断层、地层剥蚀、超覆等多种地质现象并存,地层接触关系及断裂系统复杂,给现有地震资料条件下低序级断层识别及组合带来极大的困难。针对这一难题,通过探索,形成了基于地震正演分析与井震结合的低序级断层识别与精细刻画技术：综合利用井震结合重建地层对比模式指导井上小断点的准确识别、井断点地震反射特征与地震正演结合建立断层地震识别标志、井引导地震属性分析断层平面组合规律、井震多层位精细解释刻画断棱断面及多层叠合验证空间组合关系。在“断层、剥蚀、超覆”共存的孤东二六区沙河街组,通过该方法的应用,重组了其复杂断裂系统,解决了长期以来的油水矛盾,取得了较好的应用效果。     

复杂应力路径下堆石料本构关系研究

已有研究表明,土石坝内堆石料在坝体填筑过程的应力路径可近似为等应力比的路径（q/p=常数）,水库蓄水时应力路径将发生转折,呈复杂的应力路径形态（dq/dp=常数）。在大型三轴仪上进行了两种应力路径的排水试验,即等应力比路径下的偏压试验和复杂应力路径下的剪切试验。根据试验结果提出了一个堆石料应力路径增量非线性弹性模型,模型采用三模量形式除可以描述堆石料等应力比路径的应力-应变特征外,通过转折后的路径特征构造合适的柔度矩阵,能够表达转折应力路径下的本构关系。对试验曲线进行拟合表明,应力路径模型能够较好地反映堆石料在复杂应力路径下的应力与变形特性。     

Architecture of tunnel valleys in the southeastern North Sea: new insights from high-resolution seismic imaging

Tunnel valleys are assumed to form near the margin of ice sheets. Hence, they can be used to reconstruct the dynamics of former ice margins. The detailed formation and infill of tunnel valleys, however, are still not well understood. Here, we present a dense grid of high-resolution 2D multi-channel reflection seismic data from the German sector of the southeastern North Sea imaging tunnel valleys in very great detail. Three tunnel valley systems were traced over distances ranging between 11 and 21 km. All tunnel valleys are completely filled and buried. They differ in incision depth, incision width and number of incisions. The tunnel valleys cut 130–380 m deep into Neogene, Palaeogene and Cretaceous sediments; they show a lower V-shaped and an upper U-shaped morphology. For individual tunnel valleys, the overall incision direction ranges from east–west to northeast–southwest. Two tunnel valleys intersect at an oblique angle without reuse of the thalweg. These valleys incise into a pre-existing glaciotectonic complex consisting of thrust sheets in the northwest of the study area. The analysis of the glaciotectonic complex and the tunnel valleys leads us to assume that we identified several marginal positions of (pre-)Elsterian ice lobes in the southeastern North Sea.     

复杂地质条件下桩基础施工难点分析

随着北京地区基坑深度及单桩承载力要求的提高,基础施工面在不断向下移动,桩深度也在不断加深,使得施工情况也越来越复杂,如承压水的处理,相对水位的变化、地层的变化、施工设备的选择、场地的局限性等,针对这些问题,以北京地区某工程深桩基施工为例,介绍了承压水条件下,砂层、粉粘土层和卵石层多层互层复杂地质条件下的深桩基现场施工设备的选择和现场管理工作。介绍施工过程中的一些难点、要点及其解决方法。本研究可为类似工程提供参考。     

镁—4,5—二溴苯基荧光酮络合吸附波及其应用

在ＰＨ１０．３的ＮａＢ４Ｏ７－ＮａＯＨ介质中,Ｍｇ＾２＋与４,５－二溴苯基荧光酮形成络合物,于－０．９５Ｖ出现一灵敏的阴极波。Ｍｇ＾２＋的质量浓度在８．２－５８μｇ／Ｌ时与峰电流呈线性关系,检出限为２．１μｇ／Ｌ。     

江西早二叠世晚期—晚二叠世早期的岩相古地理

摘　要　根据地层学研究的新进展‚将原乐平组的官山段和下老山段划归茅口阶‚编制了这 一时期的沉积断面图‚并对这一时期的沉积史进行了阐述。     

不同比例尺与介质中化探数据的含量-频数分形研究--以广东大宝山铜多金属矿田为例

应用含量—频数分形方法对广东大宝山矿田不同范围多介质、多比例尺地球化学场进行比较分析研究,认为成矿元素在不同比例尺与介质中呈基本一致的复杂多重分形特点,该特点是区域元素形成规模矿的一个必要条件,但不是充分条件;提出成矿元素连续多重分形的分维值减小转折点所代表的局部异常样品数所占比例在各比例尺采样介质中均大于2%,而非成矿元素该比例值可能远小于1%;拟合精度明显影响含量—频数分形曲线的类型与性质。