Geochemical Characteristics and Genetic Significance of Datangpo‐Type Manganese Ore Deposits during the Cryogenian Period     

Jiafei Xiao  Jingyang He  Haiying Yang  Chengquan Wu  Jianbin Xu  Yantao Li 《Resource Geology》2019,69(3):227-248

The Datangpo‐type manganese ore deposits, which formed during the Nanhuan (Cryogenian) period and are located in northeastern Guizhou and adjacent areas, are one of the most important manganese resources in China, showing good prospecting potential. Many middle‐to‐large deposits, and even super‐large mineral deposits, have been discovered. However, the genesis of manganese ore deposits is still controversial and remains a long‐standing source of debate; there are several viewpoints including biogenesis, hydrothermal sedimentation, gravity flows, cold‐spring carbonates, etc. Geochemical data from several manganese ore deposits show that there are positive correlations between Al₂O₃ and TiO₂, SiO₂, K₂O, and Na₂O, and strong negative correlations between Al₂O₃ and CaO, MgO, and MnO in black shales and manganese ores. U, Mo, and V show distinct enrichment in black shales and inconspicuous enrichment in Mn ores. Ba and Rb show strong positive correlations with K₂O in manganese ores. Cu, Ni, and Zn show clear correlations with total iron in both manganese ores and black shales. ∑REE of manganese ores has a large range with evident positive Ce anomalies and positive Eu anomalies. The Post Archean Australian Shale (PAAS) normalized rare earth element (REE) distribution patterns of manganese ores present pronounced middle rare earth element (MREE) enrichment, producing “hat‐shaped” REE plots. ∑REE of black shales is more variable compared with PAAS, and the PAAS‐normalized REE distribution patterns appear as “flat‐shaped” REE plots, lacking evident anomaly characteristics. δ¹³C values of carbonate in both manganese ores and the black shales show observable negative excursions. The comprehensive analysis suggests that the black shales formed in a reducing and quiet water column, while the manganese ores formed in oxic muddy seawater, which resulted from periodic transgressions. There was an oxidation–reduction cycle of manganese between the top water body and the bottom water body caused by the transgressions during the early Datangpo, which resulted in the dissolution of manganese. Through the exchange of the euphotic zone water and the bottom water, and episodic inflow of oxygenated water, the manganese in the bottom water was oxidized to Mn‐oxyhydroxides and rapidly buried along with algae. In the early diagenetic stage, Mn‐oxyhydroxides were reduced and dissolved in the anoxic pore water and then transformed into Mn‐carbonates by reacting with HCO₃^? from the degradation of organic matter or from seawater. In the intervals between transgressions, continuous supplies of terrigenous clastics and the high productive rates of organic matter in the euphotic zone resulted in the deposition of the black shales enriched in organic matter.  相似文献   

http://dx.doi.org/10.1016/j.gsf.2016.04.002   总被引：1，自引：1，他引：0  

Takanori Sasaki  Toshikazu Ebisuzaki 《地学前缘(英文版)》2017,8(2):215-222

Population synthesis studies into planet formation have suggested that distributions consistent with observations can only be reproduced if the actual Type Ⅰ migration timescale is at least an order of magnitude longer than that deduced from linear theories.Although past studies considered the effect of the Type I migration of protoplanetary embryos,in most cases they used a conventional formula based on static torques in isothermal disks,and employed a reduction factor to account for uncertainty in the mechanism details.However,in addition to static torques,a migrating planet experiences dynamic torques that are proportional to the migration rate.These dynamic torques can impact on planet migration and predicted planetary populations.In this study,we derived a new torque formula for Type Ⅰ migration by taking into account dynamic corrections.This formula was used to perform population synthesis simulations with and without the effect of dynamic torques.In many cases,inward migration was slowed significantly by the dynamic effects.For the static torque case,gas giant formation was effectively suppressed by Type I migration;however,when dynamic effects were considered,a substantial fraction of cores survived and grew into gas giants.  相似文献   

地壳形变分析的总体最小二乘配置方法     

王乐洋  陈汉清  温扬茂 《大地测量与地球动力学》2017,37(2):163-168

针对地壳形变问题中观测向量和趋势项系数矩阵均含有误差的情况,研究了总体最小二乘配置平差方法,在广义总体最小二乘准则下推导了具体的解算公式和迭代算法。利用模拟的地壳水平形变和2009年意大利L’Aquila实际地震数据进行分析,结果表明,总体最小二乘配置与传统的最小二乘配置方法在地壳形变分析中的效果基本一致,并给出了相关的理论依据。  相似文献   

多年平均气温数据空间化误差的尺度效应   总被引：1，自引：0，他引：1  

廖顺宝  张赛 《地球信息科学学报》2014,16(1):8-14

属性数据空间化是利用矢量数据生成栅格数据产品的有效方法,它有助于不同来源、不同格式之间的数据的综合分析。空间化是一种必然有误差伴随的过程,为探讨空间化误差与数据源密度、空间化模型方法,以及空间化分辨率之间的关系,本文利用7种水平的气象站点密度、5种空间化模型方法和19种栅格分辨率分析多年平均气温数据空间化误差与这3类影响因子之间的关系。分析发现：（1）气象站点密度的降低导致多年平均气温数据的空间化误差增加;（2）在IDW、Kriging、Adjusted IDW、Regression和Anusplin 5种空间化模型方法中,Adjusted IDW、Regression、Anusplin比IDW、Kriging的精度高;（3）随着栅格分辨率的变粗,多年平均气温数据空间化误差增大;（4）在影响空间化精度的3类因子中,空间化模型方法对空间化精度的影响最大,栅格分辨率次之,气象站点密度的影响最小。通过多元回归分析,建立了多年平均气温数据空间化误差与这3类影响因子之间的定量模型,可为空间化技术方案的制定提供参考和依据。  相似文献   

Characterization of error dynamics in a 3D coastal model of the Catalan sea using stochastic modelling     

Gabriel Jordà  Pierre De Mey 《Continental Shelf Research》2010

  相似文献   

山西岩溶水强径流带的成因类型及其水文地质特征   总被引：5，自引：4，他引：1  

裴捍华  杨亲民  郭振中  黄卫星 《中国岩溶》2003,22(3):219-224

根据成因特征,将山西岩溶水强径流带分为五种类型: 接触带型、河谷型、构造带型、向斜谷地型和复合型。通过野外调查及对大量实测资料的分析研究,揭示出山西岩溶水强径流带的主要发育与分布特征: 岩溶水强径流带呈网状分布;发育深度50～300m;地下水面呈槽谷型,水力坡度一般在0. 6‰～2. 8‰之间。岩溶强径流带水量丰富,单井出水量大于1000m3 /d,是建立岩溶水水源地的理想场所。   相似文献   

GRACE估计南极冰川质量变化的泄露影响及其改正     

邹芳  金双根 《大地测量与地球动力学》2016,36(7):639-644

利用2003-01～2013-12期间GRACE数据反演得到地球表面质量变化,使用全球正向建模恢复法改正泄露影响,获得南极冰盖质量变化。比较GRACE直接估计和泄露影响改正后的结果发现,南极冰盖在2003～2013年质量变化信号衰减20.3%,西南极有26.4%的质量消融信号泄露到了周边,东南极的泄露影响更高达70%。改正后的结果表明,南极冰盖绝大部分质量消融发生在西南极和南极半岛,质量积累发生在东南极的Ronne冰架和Amery冰架;西南极冰盖质量变化速度达到-152.47±2.00 Gt/a,基本上等同于南极全岛的质量消融速度,而南极半岛的冰盖融化速度为-27.44±0.75 Gt/a,基本与东南极的冰盖质量积累速度27.27±5.12Gt/a抵消;南极全岛冰川整体质量以-152.64±7.00 Gt/a速度消失,并以-18.85±4.87 Gt/a2的加速度加速融化,导致海平面以0.41 mm/a的速度上升。  相似文献   

Using stochastic state‐space modelling to specify and reduce hydrograph error     

C. G. Collier  G. L. Robbins 《水文研究》2008,22(8):1173-1179

A Bayesian post‐processor is used to generate a representation of the likely hydrograph forecast flow error distribution using raingauge and radar input to a stochastic catchment model and its deterministic equivalent. A hydrograph ensemble is so constructed. Experiments are analysed using the model applied to the River Croal in north‐west England. It is found that for rainfall input to the model having errors less than 3mm h^?1, corresponding to about a 15% error in peak flow, the stochastic model outperforms the deterministic model. The range of hydrographs associated with the different model simulations and the measured hydrographs are compared. The significant improvement possible using a stochastic approach is demonstrated for a specific case study, although the mean hydrograph derived using the stochastic model has an error range associated with it. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

GPS测量误差源及其控制分析   总被引：3，自引：2，他引：1  

贾彬 《海洋测绘》2008,28(3):76-78

介绍了GPS测量中各种主要的非人为误差以及它们给测量带来的影响，对于精度控制问题，主要讨论的是小型控制网（基线长度10～20km）和局部地区应用中动态和准动态差分测量的精度控制方法。  相似文献   

A strip adjustment procedure to mitigate the impact of inaccurate mounting parameters in parallel lidar strips     

Ayman F.  Habib  Ana Paula  Kersting  Ki-In  Bang  Ruifang  Zhai  Mohannad  Al-Durgham 《The Photogrammetric Record》2009,24(126):171-195

Lidar (laser scanning) technology has been proven as a prominent technique for the acquisition of high-density and accurate topographic information. Because of systematic errors in the lidar measurements (drifts in the position and orientation information and biases in the mirror angles and ranges) and/or in the parameters relating the system components (mounting parameters), adjacent lidar strips may exhibit discrepancies. Although position and orientation drifts can have a more significant impact, these errors and their impact do not come as a surprise if the quality of the GPS/INS integration process is carefully examined. Therefore, the mounting errors are singled out in this work. The ideal solution for improving the compatibility of neighbouring strips in the presence of errors in the mounting parameters is the implementation of a rigorous calibration procedure. However, such a calibration requires the original observations, which may not be usually available. In this paper, a strip adjustment procedure to improve the compatibility between parallel lidar strips with moderate flight dynamics (for example, acquired by a fixed-wing aircraft) over an area with moderately varying elevation is proposed. The proposed method is similar to the photogrammetric block adjustment of independent models. Instead of point features, planar patches and linear features, which are represented by sets of non-conjugate points, are used for the strip adjustment. The feasibility and the performance of the proposed procedure together with its impact on subsequent activities are illustrated using experimental results from real data.  相似文献