陇西民和黄土CaCO3和有机碳总量的含量变化及其气候指标的局限性   总被引：4，自引：0，他引：4       下载免费PDF全文

谢远云  李长安周 嘉殷鸿福 《中国地质》2003,30(1):99-104

民和黄土地处黄土高原与青藏高原东北缘的交接部位,对气候反应较敏感,对该黄土1.87-0.70Ma BP段进行了CaCO3和有机碳总量（TOC）的采样分析。民和黄土CoCO3含量在5.89%-18.63%之间变化,平均11.41%;有机碳含量较低,在0.007%-0.452%之间,平均0.088%。民和黄土中的CaCO3含量明显高于兰州、洛川和西安等地,而有机碳含量则远低于上述地区。黄土中CaCO3和有机碳含量变化反映了该区1.87Ma BP以来气候变干冷的趋向。分别受复杂的CaCO3来源与类型、困难的采样、地区上的差异对比等和有机碳保存条件、沉积速率以及“埋藏效应”的影响,黄土中的CaCO3和有机碳的波动变化作为气候变化的替代性指标存在一定的局限性。文章最后指出,在实际应用中,黄土（特别是黄土高原西北部）中CaCO3和有机碳气候指标应结合其他环境指标共同使用,才能从中提取正确的古气候信息。  相似文献   

内蒙古巴彦浩特盆地及其南缘上石炭统太原组烃源岩有机地球化学     

林海涛  张亭荣  冯岩  杨才 《地质与资源》2019,28(2):171-177

内蒙古巴彦浩特盆地广泛发育上石炭统太原组煤系烃源岩.在野外地质勘查、典型剖面实测、样品采集及实验分析基础上,开展了有机质丰度、有机质类型、有机质成熟度等有机地球化学特征分析与研究,初步对其生烃潜力进行评价.结果表明：太原组烃源岩有机质丰度高,热演化程度属于成熟—高成熟演化阶段,具备较好的页岩气气源条件.通过多因素叠加分析的方法,圈定了页岩气成藏有利区3处,分别是北部的查干布拉格有利区、通古勒格淖尔嘎查－伊克尔嘎查苏木有利区和南部的下河沿－营盘水有利区.  相似文献   

烟台四十里湾表层沉积物有机质来源及环境意义   总被引：5，自引：3，他引：2  

刘东艳  申旭红  王玉珏  陈颖军  李丽 《海洋学报》2012,34(5):205-212

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Spatial and temporal variations of sedimented organic matter in Xiaohai Lagoon, Hainan Island   总被引：1，自引：1，他引：0  

LIU Xingjian  GE Chendong 《海洋学报(英文版)》2012,31(3):74-86

The characteristics of grain-size,total organic carbon(TOC) and total nitrogen(TN) contents,TOC/TN ratios,stable carbon isotope(δ13C) and 210 Pb dating were measured in six sediment cores from the Xiaohai Lagoon.The results show distinct spatial and temporal variations in sedimentation patterns.The sediments are dominated by clayey silt,sandy silt and by silty sand in the southern,middle lagoon and the northern lagoon,respectively.TOC and TN contents decline from south to north.Sedimentation rates,determined by 210 Pb dating,tend to decrease from south to middle.However,the determination of sedimentation rate in the north is difficult.These spatial variations are related to the variations in sediment sources and hydrodynamic conditions in the Xiaohai Lagoon.The variations of organic matter signatures can be divided into two stages in the cores from the southern and middle lagoon.Before 1988,the organic matter signatures are relatively stable.The contribution of terrestrial organic carbon sources varies between 60% and 85%.After 1988,the organic matter signatures demonstrate significant variations.TOC and TN contents increase rapidly,TOC/TN ratios decrease,δ13C values shift to higher and the contribution of terrestrial organic carbon sources decreases to 40%-50%.The contributions of phytoplankton organic matter have increased in the sediment since 1988.Increasing aquaculture activities have had a significant impact on organic matter signatures since 1988.The sedimentation rates have increased rapidly in the southern and middle lagoon since 1988 due to the anthropogenic activities which include aquaculture,mining and deforestation.These activities have caused eutrophication and increased siltation in the southern and middle lagoon.  相似文献   

Novel deseasonalizing models for improving the prediction of total ozone in column using evolutionary programming and neural networks     

S. Salcedo-Sanz  J.L. Camacho  .M. Prez-Bellido  E. Hernndez-Martín 《Journal of Atmospheric and Solar》2010,72(18):1333-1340

In this paper we present a novel method for deseasonalizing TOC data using non-linear models, with evolutionary computation techniques, and its performance with a neural network as regression approach. Specifically, the proposed deseasonalization method uses an evolutionary programming (EP) approach to carry out a curve fitting problem, where a given function model is optimized to be as similar as possible to an objective curve (a real TOC measurement in this case). Different non-linear models are proposed to be optimized with the EP algorithm. In addition, we test the possibility of deseasonalizing the TOC measurement and also the meteorological input data. The deseasonalized series is then used to train a neural network (multi-layer perceptron). We test the proposed models in the prediction of several TOC series in the Iberian Peninsula, where we carry out a comparison against a reference deseasonalizing model previously proposed in the literature. The results obtained show the good performance of some of the deseasonalizing models proposed in this paper.  相似文献   

Electro‐Catalytic Degradation of Phenol Organics with SnO2‐Sb2O3/Ti Electrodes     

Kaijin Zhu  Wencai Zhang  Huifang Wang  Zhongliang Xiao 《洁净——土壤、空气、水》2008,36(1):97-102

The effect of extraordinary degradation of phenol organics on the SnO₂‐Sb₂O₃/Ti electrode is investigated through experimental research and theoretical analysis. The phenol organics contained 4‐chloro‐phenol, 4‐bromo‐phenol, and 2‐iodo‐phenol. At a current density of 4 mA cm^–2 and an electrolysis time of 12 h, the degradation efficiency of the phenols was over 98% with a relatively short degradation time, whereas the degradation time of the PbO₂/Ti electrode surpassed 40 h while delivering 100% disposal efficiency. Therefore, the effectiveness of electrochemical (EC) oxidation by the SnO₂‐Sb₂O₃/Ti was superior to that of the PbO₂/Ti electrode. At the same time, the SnO₂‐Sb₂O₃/Ti had higher oxygen generation potential and lower electron consumption than the other electrodes. This was mainly due to the effect of the middle Sb₂O₃ layer, which due to its high porosity and good catalytic effect, contributed to a better catalysis than the SnO₂ part.  相似文献   

Levels and distribution of tris-(2,3-dibromopropyl) isocyanurate and hexabromocyclododecanes in surface sediments from the Yellow River Delta wetland of China     

Ling Wang  Mengyuan Zhang  Yinghua Lou  Runhui Ke  Minggang Zheng 《Marine pollution bulletin》2017,114(1):577-582

The levels and distribution of tris-(2,3-dibromopropyl) isocyanurate (TBC) and hexabromocyclododecanes (HBCDs) of surface sediments in the Yellow River Delta wetland had been investigated. The concentrations of TBC and ∑ HBCDs ranged from 0.20 to 29.03 ng·g^? 1 dw and below limits of detections (LODs) to 20.25 ng·g^? 1 dw. The average composition profile of three HBCDs isomers were 10.1%, 6.1% and 83.8% for α-, β- and γ-HBCD, respectively. Moreover, correlation analysis indicated there are similar sources among three isomers and positive correlations between total organic carbon (TOC) content and concentrations of TBC and HBCDs. The mass inventory of TBC,α-, β-, γ-HBCD, ΣHBCDs in surface sediments of Yellow River Delta wetland were estimated about 725.50, 72.76, 44.29, 548.34, 665.39 kg. Therefore, further investigations on potential human health and environmental risk assessments of TBC and HBCDs were needed.  相似文献   

色度学指标反映古气候的探索研究——以松辽盆地晚白垩世土伦阶（Turonian）为例     

赵斌  王亚芳  吴德新  黄永建 《吉林地质》2013,(4):1-6

本文运用色度学方法对采自松辽盆地＂松科Ⅰ井＂南孔的上白垩统泉头组四段（K2q4）、青山口组一段（K2qn1）的51件样品进行了研究,得出以下结论：（1）利用CIE1976 L＊a＊b＊表色系统分析发现,样品的色度参数L＊和a＊,b＊和a＊呈显著的负相关性（负相关系数分别达到-0.564和-0.663）,L＊和b＊则呈显著的正相关性。（2）样品的色度参数与总有机碳质量分数（TOC%）的相关性分析表明,b＊和TOC%呈现较显著的负相关性,TOC%与L＊和a＊的相关性不明显。有机碳作为碳旋回中的一部分,对松辽盆地古气候的研究具有举足轻重的意义,b＊受到总有机碳质量分数（TOC%）的制约,可以在一定程度上作为反映古气候变化的替代指标。  相似文献   

基于贝叶斯正则化改进BP神经网络的页岩气有机碳含量预测模型   总被引：2，自引：0，他引：2  

袁颖  谭丁  于少将  李杨  韩冰 《地质与勘探》2019,55(4):1082-1091

页岩气总有机碳(TOC)含量是评价岩性气藏的关键指标,受复杂地质及岩芯采集等多种因素的影响,常规室内测试分析获得的TOC含量的数据有限且结果有失准确。为合理准确预测页岩气TOC含量,本文首先通过对页岩气储层TOC含量测井资料综合分析选取8条测井曲线,并结合主成分分析法(Principal Component Analysis,PCA)提取四个主成分;其次基于贝叶斯正则化(Bayesian Regularization)改进的BP神经网络方法建立页岩气TOC含量预测的BR-BP模型;最后利用该模型对研究区A区页岩气TOC含量进行预测,并与常规的LM-BP神经网络模型的预测结果进行对比。结果表明：BR-BP模型有较强的非线性拟合能力,能够真实地反映出页岩气TOC含量与各测井参数之间的非线性关系,其模型预测结果与实际值基本吻合,与常规的LM-BP神经网络模型相比,其数据敏感性增强,预测精度有所提高,该研究方法具有一定的理论意义和参考价值,为我国TOC含量预测提供了一种新的技术方法和手段。  相似文献   

Macro- and megafauna communities in three deep basins of the South-East Atlantic     

《Deep Sea Research Part I: Oceanographic Research Papers》2013

During ‘Meteor’ expedition ‘DIVA 2’ in 2005 the abyssal macro- and megafauna communities were studied in the northern Cape Basin, in the northern Angola Basin and in the eastern and western Guinea Basin. Water depths varied between 5040 and 5670 m.Surface deposit feeding or predatory ophiuroids dominated the megafaunal community in the northern Cape Basin, sponges, sipunculids and fish in the northern Angola Basin, and asteroids, crustaceans and fish in the eastern Guinea Basin, while in the western Guinea Basin sipunculids dominated.In the northern Cape Basin, peracarid crustaceans were the dominant macrofaunal group, followed by polychaetes and bivalves. In the Guinea Basin, polychaetes, peracarid crustaceans and bivalves dominated, although omnivorous or predatory free-living nematodes of macrofaunal size (>0.5 mm) made up 40–60% of the total abundance, with maxima in the western basin.The chlorophyll a content of sediments was lower in the northern Cape and Angola Basins than in the Guinea Basin, which was consistent with the differences in water masses, primary production and flux rate of organic matter in the three basins of the South-East Atlantic. The differences in structure and function of the macro- and megafauna communities in the three basins correlated with the differences in the amount of food reaching the seafloor in tropical and subtropical settings.  相似文献