Progress on Sedimentation of Subaqueous Volcanic Eruption

In recent years, more and more originally regarded as black oil and gas-bearing shales have been found, whose formation has close relationship with subaqueous volcanic activities, with much more fundamental research work on tight oil in China. However, our study of sedimentations of subaqueous eruption has not been well studied since their sediments are very tiny, not easy to be sampled, and extremely difficult to differentiate from mud-size clastic sediments. This paper reviewed the advances of the processes of fragmentation, transportation, and deposition of sediments originated by subaqueous eruption, on the basis of publications and research experience on some special intervals in interlaminated shales and dolostones in Permian Lucaogou Formation in Santanghu Basin. Three main features and their implications were documented. ① Minerals in those intervals were angular with a low component maturity, and some of them were shard-like, suggesting volcanic-eruptive origin. ② Intervals were laminated and thin bedded. The former had a sharp erosional base, and was internal normal graded, and showed crude orientation of elongate grains parallel to bedding plane, suggesting deposition of lateral tractive current; the latter showed messy accumulation without internal structure, suggesting deposition of dense granular flow. ③ Intervals were localized and repetitive in stratigraphy, indicating origin from episodic-pulsating volcanic activities. We preliminarily interpreted those intervals as sedimentations of subaqueous volcanic-hydrothermal activities (phreatomagmatic/hydrovolcanic deposition). Then, the relationship of intraclasts, extraclasts, and deep-derived clasts, the difference of sedimentary rocks formed by subaqueous between subaerial eruptions, and the terminology of these eruptive rocks were discussed. Finally, macro to micro scale observation, micro-texture of minerals, attaching importance on hydrothermal exhalative sedimentations, and multidisciplinary studies were suggested for future research on those rocks.     

FBG温度低敏传感器在大型钢结构施工监测中的运用

目前在桥梁、钢结构等表面应力监测领域中,光纤光栅因具有抗电磁干扰能力强、灵敏度高、环境适应能力强、使用寿命长等优点,已经成为一种新的先进监测、检测手段,但FBG波长随温度变化而产生的漂移往往严重影响监测系统的性能,因此需要对FBG进行温度补偿。介绍了一种新型的FBG传感器并结合具体的工程项目,论述了其温度低敏技术能精确地剔除温度对应变的影响,实现结构物的长期健康监测。     

An experimental study of effect of pre‐existing fabric on deformation of foliated mylonite at high temperature and pressure

We performed deformation experiments on a foliated mylonite under high temperature and pressure conditions in this study. To investigate the effect of pre‐existing fabric on the rheology of rocks, our samples were drilled from natural mylonite with the cylinder axis parallel to the foliation (PAR) and perpendicular to the foliation (PER). We performed 25 tests on seven PAR samples and 21 tests on seven PER samples at temperatures ranging from 600 to 890 °C, confining pressures ranging from 800 to 1400 MPa, and steady‐state strain rates of 1 × 10⁻⁴, 1 × 10⁻⁵ and 2.5 × 10⁻⁶ s⁻¹. In the temperatures of 600–700 °C, the deformation is accommodated by semi‐brittle flow, with the average stress exponent being 6–7 assuming power law flow; in the temperature range of 800–890 °C, deformation is mainly by plastic flow, with an average stress exponent of n = 3 and activation energies of Q = 354 ± 52 kJ/mol (PER and PAR samples). The experimental results show that the strengths of PER samples are higher than those of PAR samples. Deformation microstructures have been studied by optical and electron microscopy. The original foliation of PER samples is destroyed by deformation and replaced by a new foliation, but the deformation of PAR samples followed the original foliation. Electron backscatter diffraction (EBSD) measurements show a strong lattice preferred orientation (LPO) of the quartz c axis fabrics of the starting samples and deformed PER and PAR samples. However, the c axis fabric of quartz in experimentally deformed PER and PAR samples varied with temperature and strain rate is different from that seen in the starting mylonite sample. The initial quartz c axis fabric of the starting mylonite sample has been transformed into a new fabric during experimental deformation. Dehydration melting of biotite and hornblende occurred in both PER and PAR samples at temperatures of 800–890 °C. Copyright © 2014 John Wiley & Sons, Ltd.     

分形几何用于岩石损伤扩展过程的研究

通过对岩石损伤扩展机理的研究，运用分形几何理论，建立了岩石损伤变量ω与分形维数之间关系。     

右江褶皱带有金属矿床成矿系列初步研究

右江褶皱带位于华南褶皱系的南西端，地质构造复杂，有色金属矿产丰富，本文对该区有色金属矿床的两个主要成矿系列进行了研究，一是与重熔型花岗岩类有关的锡－铜－银多金属矿床成矿系列，其中又可将其分为锡－铜与银多金属两个亚系列，二是沉积－改造型层控锑矿床成矿系列，本文以上旧，都龙，白占厂，德保，凤凰山和木利，马雄等矿床为实例，分别讨论了两个成矿系列的主要特征，控矿因素和矿床成因。     

An SIMS Study on the Fingerprint Characteristics of Minerais with Special Reference to Minerais from the Jinningian Granites in the Yunnan Sector of the Xikang-Yunnan Axis

Abstract In this paper such minerais as apatite, zircon and biotite from granites were determined and analyzed by secondary ion mass spectrometry (SIMS) for their isotopic ages, REE composition, trace elements and volatile components with an attempt to shed light on the origin and formation environments of the Jinningian granites in the Yunnan sector of the Kangdian (Xikang- Yunnan) earth's axis. The results show that the apatites, zircons and biotites of different geneses possess different fingerprint characteristics. Some correlations have been found between trace elements and volatile components contained in the minerais from granties.     

One‐dimensional consolidation with a threshold gradient: a Stefan problem with rate‐dependent latent heat

During the process of one‐dimensional consolidation with a threshold gradient, the seepage front moves downward gradually, and the problem is indicated as a Stefan problem. The novel feature in this Stefan problem is a latent heat that varies inversely with the rate of the moving boundary. An exact solution for the external load that increases in proportion to the square root of time is constructed using the similarity transformation technique. Computational examples concerning the effect of different parameters on the motion of the seepage front are presented. The exact solution provides a worthwhile benchmark for verifying the accuracy of numerical and approximate methods. Copyright © 2013 John Wiley & Sons, Ltd.     

A simplified analysis approach for the effect of the installation of adjacent XCC pile on the existing single XCC pile in undrained clay

Acta Geotechnica - In this paper, a simplified two-stage analysis method is introduced to predict the lateral response of the existing X-section Cast-in-place Concrete (XCC) pile caused by adjacent...     

Modeling of the Correlation Between Mineral Size and Shale Pore Structure at Meso- and Macroscales

Mathematical Geosciences - Inorganic pore structures are critical to understand the oil and gas transport and storage properties of unconventional reservoirs. However, it can be difficult to...