秦岭构造带的东延兼述其高压变质带的形成深度与机制

在介绍郯庐断裂东西两侧ＥＷ向构造基本特征的同时,从将秦岭带理解为高级协和函数和边界条件差异及构造复合等方面具体探讨了下述问题：为什么秦岭东延后构造形迹显得宽散零落？ＮＥ向的苏鲁变质岩构造带何以也成为秦岭构造带的成份？重塑了“老淮阳弧构造”,指出在郯庐断裂东侧,古老的秦岭带发生北移,中新生代秦岭带又在原水的纬度上产生,其构造形迹北抵海州湾两侧,南达杭州湾附近。还探讨了该区高压变质带的形成深度和动力学     

The application of high-resolution 3D seismic data to model the distribution of mechanical and hydrogeological properties of a potential host rock for the deep storage of radioactive waste in France

In the context of a deep geological repository of high-level radioactive wastes, the French National Radioactive Waste Management Agency (Andra) has conducted an extensive characterization of the Callovo-Oxfordian argillaceous rock and surrounding formations in the Eastern Paris Basin. As part of this project, an accurate 3D seismic derived geological model is needed. The paper shows the procedure used for building the 3D seismic constrained geological model in depth by combining time-to-depth conversion of seismic horizons, consistent seismic velocity model and elastic impedance in time. It also shows how the 3D model is used for mechanical and hydrogeological studies. The 3D seismic field data example illustrates the potential of the proposed depth conversion procedure for estimating density and velocity distributions, which are consistent with the depth conversion of seismic horizons using the Bayesian Kriging method. The geological model shows good agreement with well log data obtained from a reference well, located closest to the 3D seismic survey area.Modeling of the mechanical parameters such as shear modulus, Young modulus, bulk modulus indicates low variability of parameters confirming the homogeneity of the target formation (Callovo-Oxfordian claystone). 3D modeling of a permeability index (Ik-Seis) computed from seismic attributes (instantaneous frequency, envelope, elastic impedance) and validated at the reference well shows promising potential for supporting hydrogeological simulation and decision making related to safety issues.     

Study of the spatial and historical distribution of sediment inorganic contamination in the Toulon bay (France)

This study presents trace elements levels in surface and deep sediments of the Toulon bay (SE France) subjected to anthropogenic inputs (navy base, harbors, etc.). The studied elements (As, Cd, Cr, Cu, Hg, Ni, Pb, Zn) are defined as priority contaminants in aquatic systems. Fifty-five points scattered on the entire bay were sampled, allowing the determination of contaminants distribution with a high resolution. Several approaches were used to assess the degree of contamination and the potential toxicity of the Toulon bay sediments: comparison to the French legislation, surface-weighted average metal concentrations, enrichment factors (EF), geoaccumulation indices (Igeo), trace element stock calculation and comparison to sediment quality guidelines. A principal component analysis was performed to reveal common behavior of the studied contaminants. Results demonstrated the very high contamination of the small bay, especially in Hg (EF up to 1500), Cu, Pb and Zn, with export to the large bay further governed by hydrodynamics.     

A comparative study of the depth of maximum of simulated air shower longitudinal profiles

A comparative study of simulated air shower longitudinal profiles is presented. An appropriate thinning level for the calculations is first determined empirically. High statistics results are then provided, over a wide energy range (10^14.0–10^20.5 eV), for proton and iron primaries, using four combinations of the and program frameworks, and the SIBYLL and QGSjet high energy hadronic interaction models. These results are compared to existing experimental data. The way in which the first interaction controls X_max is investigated, as is the distribution of X_max.     

FY-3A/MERSI海上沙尘天气气溶胶光学厚度反演

利用FY-3A/MERSI资料,结合MODIS C005算法的海上气溶胶模型,研究了中国渤海、黄海以及东海海域沙尘天气气溶胶光学厚度反演方法。通过MERSI反演的气溶胶光学厚度与MODIS C005气溶胶光学厚度产品(MOD04)对比,发现MERSI气溶胶光学厚度反演结果存在较大偏差。分析认为,这种偏差是由MODIS C005算法的海上气溶胶模型对MERSI气溶胶光学厚度反演不完全适用造成的。鉴于此,本文研究引进了一种沙尘气溶胶模型,并将其与MODIS C005算法的粗粒子气溶胶模型按照一定比例混合,形成了改进的气溶胶模型。利用改进气溶胶模型再次反演海上沙尘天气气溶胶光学厚度,反演结果与MOD04一致性较好,说明改进气溶胶模型能有效地提高MERSI定量反演沙尘气溶胶的能力。     

Interpretation of tensor gravity data using an adaptive tilt angle method

Full Tensor Gravity Gradiometry (FTG) data are routinely used in exploration programmes to evaluate and explore geological complexities hosting hydrocarbon and mineral resources. FTG data are typically used to map a host structure and locate target responses of interest using a myriad of imaging techniques. Identified anomalies of interest are then examined using 2D and 3D forward and inverse modelling methods for depth estimation. However, such methods tend to be time consuming and reliant on an independent constraint for clarification. This paper presents a semi‐automatic method to interpret FTG data using an adaptive tilt angle approach. The present method uses only the three vertical tensor components of the FTG data (T_zx, T_zy and T_zz) with a scale value that is related to the nature of the source (point anomaly or linear anomaly). With this adaptation, it is possible to estimate the location and depth of simple buried gravity sources such as point masses, line masses and vertical and horizontal thin sheets, provided that these sources exist in isolation and that the FTG data have been sufficiently filtered to minimize the influence of noise. Computation times are fast, producing plausible results of single solution depth estimates t hat relate directly to anomalies. For thick sheets, the method can resolve the thickness of these layers assuming the depth to the top is known from drilling or other independent geophysical data. We demonstrate the practical utility of the method using examples of FTG data acquired over the Vinton Salt Dome, Louisiana, USA and basalt flows in the Faeroe‐Shetland Basin, UK. A major benefit of the method is the ability to quickly construct depth maps. Such results are used to produce best estimate initial depth to source maps that can act as initial models for any detailed quantitative modelling exercises using 2D/3D forward/inverse modelling techniques.     

云南马关扣哈锡、钨多金属矿成矿远景初探

矿区位于云南省东南部,老君山花岗岩北西侧接触带部位上,属南岭花岗岩系列.矿床严格受东西向构造破碎带控制,属典型中高温热液云英岩脉型锡钨矿床.     

基于CyGNSS数据的土壤水分与植被光学厚度反演研究

本文提出了一种仅基于CyGNSS数据,能够同时反演土壤水分与植被光学厚度的方案,该方案使用了神经网络与暴力穷举算法.首先考察了2018年以及2020年的数据,并对结果进行了验证.通过分析发现反演结果与参考数据展现了良好的一致性.土壤水分的反演结果与2018年和2020年的测试数据比较,其相关系数分别高达0.86和0.84,均方根误差分别为0.064和0.071 cm³/cm³;对于植被光学厚度,2018年与2020年的相关系数均为0.98,均方根误差分别为0.079和0.084.研究结果表明,CyGNSS可作为一种新型且独立的泛热带土壤水分与植被光学厚度反演手段.     

Impacts of the wintertime mesozooplankton community to downward carbon flux in the subarctic and subtropical Pacific Oceans

We compared wintertime depth distributions of the mesozooplankton community and dominant copepods between the subtropical (S1) and subarctic (K2) Pacific Oceans to evaluate the relative importance of actively transported carbon by vertical migrants to sinking particulate organic carbon flux. Primary production was higher and the ratio of sinking particulate organic carbon flux to primary production was lower at S1 compared with those at K2. The mesozooplankton community was lower in abundance and biomass at S1 compared to K2. Copepods were the dominant group among both mesozooplankton abundance and biomass throughout the water column down to 1000 m at both sites. The depth distribution showed that diel vertical migration was obvious for the mesozooplankton abundance and biomass at S1 but was not apparent for the abundance at K2, because the dominant component was diurnally migrating species at S1 and overwintering species residing at mesopelagic depths at K2. The major components of diel migrants were copepods and euphausiids at S1 and only euphausiids at K2. Respiratory flux by the diurnally migrating mesozooplankton was estimated to be 2 mgC m⁻² day⁻¹ at S1 and 7 mgC m⁻² day⁻¹ at K2. The respiratory flux was equivalent to 131% of sedimentary fecal pellet flux at S1 and 136% of that at K2. Because pathways of downward carbon flux are facilitated by the mesozooplankton community, the actively transported carbon (respiration of dissolved inorganic carbon, excretion of dissolved organic carbon and egestion of fecal pellets at depth) might be larger during winter than the flux of sinking fecal pellets.     

Bearing capacity of rectangular footings in uniform clay with deep embedment

This letter is concerned with the undrained bearing capacity of rectangular footings with various aspect ratios and embedment ratios in uniform clay. It covers thin plate foundations with low aspect ratios and high embedment depth with embedment ratio up to 150. The work is based on small strain finite element analysis (FEA). After verification of the FEA model against existing solutions of the bearing capacity factors of rectangular footings, a series of FEA results are obtained. Based on the FEA results, a simple formulation is proposed to calculate the bearing capacity factor for rectangle footing with different aspect ratio in any embedment depth, extending the existing solutions to cover a wider ranges of footing aspect ratios and embedment ratios.