不同应力状态和摩擦系数对综合P波辐射花样影响的模拟研究

为研究不同应力状态(包括主应力相对大小)和摩擦系数对大量地震P波初动辐射花样(综合P波辐射花样)的影响,首先给出了不同应力状态下的剪应力、摩擦应力和库仑破裂应力在断层面法向上的三维分布.表明即使在不考虑摩擦的情况下,剪应力在不同取向断层面上的分布也有很大差别,摩擦应力也在不同取向断层面上造成一定影响.其次,根据库仑破裂...     

基于改进的广义S变换的低频吸收衰减梯度检测

本文利用一种改进的广义S变换对地震波进行时频分解,求取地震波低频段时频谱的吸收衰减梯度,并与利用传统的广义S变换得到的高频段及低频段的吸收衰减梯度进行对比,以期更好地指示油气.理论推导、数值模拟及实际应用结果表明:基于改进的广义S变换的低频吸收衰减梯度可与传统的广义S变换得到的高频吸收衰减梯度相互佐证,更好指示油气.     

A multi-proxy approach to assessing isolation basin stratigraphy from the Lofoten Islands, Norway

This study takes a comprehensive approach to characterizing the isolation sequence of Heimerdalsvatnet, a coastal lake in the Lofoten Islands, northern Norway. We use established methods and explore new techniques to assess changes in marine influence. Bathymetric and sub-bottom profiles were acquired to examine basin-wide sedimentation and a 5.8 m sediment core spanning the last 7800 cal yr BP was analyzed. We measured magnetic susceptibility, bulk organic matter properties, molecular biomarkers, diatom assemblages, and elemental profiles acquired by scanning X-ray fluorescence. These characteristics of the sediment reflect detailed changes in salinity and water column conditions as the lake was progressively isolated. Three distinct litho/chemo-stratigraphic units represent a restricted marine phase (7800-6500 cal yr BP), a transitional phase characterized by intermittent marine influence (6500-4900 cal yr BP), and complete isolation and freshwater sedimentation (4900 cal yr BP to present). Although there are uncertainties in the estimate of the threshold elevation of the lake, the timing of these phases generally corresponds with previous interpretations of the local relative sea-level history. This record captures sea-level regression following the Tapes transgression and supports the interpretation of a subsequent sea-level stillstand, dated in Heimerdalsvatnet from 6500 to 4900 cal yr BP.     

深层海相碳酸盐岩优质储层的形成、保存和破坏机制

四川盆地震旦系—志留系碳酸盐岩普遍埋藏深度超过3〖CS％0,0,0,0〗〖CS〗500 m,属深层碳酸盐岩储层范畴。宽广的潮坪相和陆棚相沉积环境从根本上决定了盆内下组合碳酸盐岩储层岩石类型主要为颗粒碳酸盐岩、晶粒结构白云岩及裂缝性灰岩。多期次的构造运动导致下组合岩溶储层发育,特别是志留纪末期的加里东运动导致从乐山—龙女寺古隆起核部由西向东依次发育震旦系、寒武系和奥陶系古岩溶带。现今下组合储层中广泛分布的沥青表明下组合曾有过广泛的油气成藏过程,形成古油藏或古气藏,亦表明下组合在油气充注时曾普遍发育优质储层。岩石学和地球化学研究表明,复杂多变、期次繁多的成岩演化和流体充注与下组合优质储层的形成、保存和破坏密切相关,总体上,对四川盆地深层海相碳酸盐岩储层而言： 1）原位沉积体系、白云岩化对震旦系和寒武系优质储层发育控制作用弱、仅对奥陶系和志留系具有较强的控制作用; 2）古隆起是优质储层发育的先决条件,表生岩溶与破裂作用为必备条件; 3）烃类流体充注和热裂解作用早期优质储层保存的主要机制,此外,适度的重结晶作用是形成优质储层的持久动力,埋藏过程中外源侵蚀性流体溶蚀作用的储层效应有限; 4）压实压溶作用、胶结充填作用是储层致密的最主要的因素。     

云南泸水外岩房锡钨矿床地质特征

锡钨矿体产于志本山岩体外接触带、上寒武统核桃坪组下段砂板岩层间破碎带的蚀变闪长—辉长岩脉带中,少数矿体产于岩体内接触带上.矿床成因属于与混合岩化后期派生岩浆有关的高—中温热液矿床.     

K-Ar和40Ar/39Ar定年数据质量评价与Q值提出

K-Ar和K-Ar/39Ar的定年测试质量的评价是正确运用测试结果的前提.过去的研究,多通过仪器测试的偏差和误差传递来评价测试结果可靠性和精度.MSWD和Probability的提出,给出测试的内外误差概念,因考虑了仪器和样品二者的匹配性而得到广泛应用.这也说明,影响K-Ar和40Ar/39 Ar的定年测试结果的因素可以是来自仪器设备,也可以来自样品自身的特性.本文由K-Ar和40 Ar/39 Ar的定年技术的原理、流程为出发点,通过对各个测试项的误差传递和对结果精度影响的数学方法评估,提出了影响测试精度的Q1和Q2参数,分别代表与样品有关的属性.Q1是样品钾含量、囚禁36 Ar的含量、以及样品40Ar/36Ar的初始比值的综合参数,是决定仪器测试中误差传递系数大小的重要影响因子.Q2是样品钾含量、囚禁36 Ar的含量、以及样品40 Ar/36 Ar的初始比值误差的综合参数,用来评价样品等时线年龄精度.在地质意义上,Q2是评价样品是否满足“同源、同时、封闭”特性的重要量化指标.根据这两个参数,可以判别测试数据质量优劣是源于测试仪器,还是样品属性.由Q1和Q2的分析可知,任何一项K-Ar和40Ar/39 Ar的定年测试都应该充分考虑仪器性能和样品属性,设计合理的测试流程是K-Ar和40 Ar/39 Ar的定年获得较高质量数据的关键.     

http://www.sciencedirect.com/science/article/pii/S1674987112001302

We present relative sea level （RSL） curves in Antarctica derived from glacial isostatic adjustment （GIA）predictions based on the melting scenarios of the Antarctic ice sheet since the Last Glacial Maximum （LGM）given in previous works.Simultaneously,Holocene-age RSL observations obtained at the raised beaches along the coast of Antarctica are shown to be in agreement with the GIA predictions.The differences from previously published ice-loading models regarding the spatial distribution and total mass change of the melted ice are significant.These models were also derived from GIA modelling; the variations can be attributed to the lack of geological and geographical evidence regarding the history of crustal movement due to ice sheet evolution.Next,we summarise the previously published ice load models and demonstrate the RSL curves based on combinations of different ice and earth models.The RSL curves calculated by GIA models indicate that the model dependence of both the ice and earth models is significantly large at several sites where RSL observations were obtained.In particular,GIA predictions based on the thin lithospheric thickness show the spatial distributions that are dependent on the melted ice thickness at each sites.These characteristics result from the short-wavelength deformation of the Earth.However,our predictions strongly suggest that it is possible to find the average ice model despite the use of the different models of lithospheric thickness.By sea level and crustal movement observations,we can deduce the geometry of the post-LGM ice sheets in detail and remove the GIA contribution from the crustal deformation and gravity change observed by space geodetic techniques,such as GPS and GRACE,for the estimation of the Antarctic ice mass change associated with recent global warming.     

The sustainable use and conservation of biodiversity in ABNJ: What can be achieved using existing international agreements?

While the international community debates the desirability and possible content of a new global instrument for the conservation and sustainable use of marine biodiversity in areas beyond national jurisdiction, alternative approaches to improving the application and implementation of existing agreements for the protection of biodiversity appear to have fallen off the agenda. Recent practice under existing global and regional agreements suggests that, given political will, significantly greater protections could be achieved through the more effective implementation of individual sectoral agreements. However, while single-sector measures have the potential to make a valuable contribution, ultimately only multi-sectoral, integrated, cooperative management can ensure the conservation and long-term sustainable use of marine biodiversity in ABNJ. This requires establishing mechanisms for cooperation both intra and inter-sectorally, as well as between the sectoral and global and regional conservation agreements. This paper examines recent initiatives within various sectoral and conservation treaty regimes aimed at improving their application within ABNJ as well as some of the challenges to, and options for, further and better cooperation and coordination among and between existing regimes, and it identifies a range of possible mechanisms for achieving more effective implementation and coordination among them. Greater use of existing mechanisms represents a sensible approach to making the most of existing arrangements without in any way foreclosing the possibility of the adoption of a more comprehensive, integrated global agreement for the protection of marine biodiversity in ABNJ.     

最大熵原理在闪电时程方程中的应用分析

以最大熵原理为依据,首先通过对雷暴过程中闪电总量与闪电频次的关系分析,得到一分布函数。然后进一步讨论相对闪电量与相对历时时间之间的函数关系,建立闪电时程方程。最后选取江苏省闪电定位仪监测记录中2007—2009年20次雷暴日资料,进行分析计算,论证了最大熵原理在闪电时程中应用的可行性。