承德地区石炭-二叠系层序岩相古地理     

朱宝存  唐书恒  张佳赞  张钊 《中国煤炭地质》2009,(1):5-8

将层序地层学方法应用于岩相古地理研究中,首先建立承德地区石炭一二叠系层序地层格架,然后以四级层序为基本编图单元,编制岩相古地理图。分析了石炭一二叠系的沉积演化特征,讨论了层序地层、岩相古地理与聚煤作用的关系。在研究区识别出2个三级层序、5个四级层序、8个五级层序;揭示了海平面升降变化对成煤沼泽发育的控制,认为层序DS1的海侵或海退最大点处的四级层序Ⅲ控制了研究区两个主采煤层的发育。该结论对该区聚煤规律的研究和煤炭资源预测有一定的参考价值。  相似文献   

Automated Segmentation of Resistivity Image Logs Using Wavelet Transform     

Marina Hruška  William Corea  Donald Seeburger  William Schweller  William H. Crane 《Mathematical Geosciences》2009,41(6):703-716

We describe a wavelet-transform-based method for automated segmentation of resistivity image logs that takes into account the apparent dip in the data and addresses the problem of discriminating lithofacies boundaries from noise and intrafacies variations. Our method can be applied to borehole measurements in general, but might have an advantage when applied to resistivity image logs as it addresses explicitly the large variability in facies segments recorded with a high-resolution multiple-sensor tool. We have developed an algorithm based on this method that might outperform other existing segmentation methods in the cases of low to moderate dip. We made a detailed comparison of the segmentation from our method with the one done by a geologist to delineate different lithofacies blocks in a well drilled in a deepwater depositional environment. Our results show considerable success rates in reproducing the geologically defined lithofacies boundaries, and the generality of our procedure suggests it could also be applied to other depositional environments.  相似文献   

Geochemistry,Paleoenvironment and Mechanism of Organic-Matter Enrichment in the Lower Silurian Longmaxi Formation Shale in the Sichuan Basin,China     

CHEN Zhipeng  CUI Junping  REN Zhanli  JIANG Shu  LIANG Xing  WANG Gaocheng  ZOU Chen 《《地质学报》英文版》2019,93(3):505-519

To investigate the mechanism of the organic-matter enrichment in the Lower Longmaxi Formation shale, the geochemistry and total organic carbon(TOC) of the Longmaxi Formation black shales in the Jiaoshiba, Zhaotong, and Weiyuan areas of the Sichuan Basin were analyzed. Paleoproductivity proxy parameters(Babio, Siex, and Ni/Al), clastic influx proxies(TiO_2 and Ti/Al), redox indices(V/Cr, Ni/Co, V/(V+Ni), and U/Th), and hydrothermal indicators(Fe, Mn,and Y concentrations; Fe/Ti ratio and a Ni-Zn-Co diagram) were employed to decipher the paleoenvironment of the Lower Longmaxi Formation shales. TiO_2 and Ti/Al indicated low terrigenous detrital influx in all three areas. However, Babio, Siex,and Ni/Al indicated high productivity in the Jiaoshiba area. V/Cr, Ni/Co, and U/Th indicated higher oxygen content with larger fluctuations in the Zhaotong and Weiyuan areas. Fe, Mn, and Y concentrations and the Fe/Ti ratio implied greater active hydrothermal activity in the Weiyuan area. These heterogeneities were considered to be closely related to the paleoenvironment and paleogeography, and the large basement faults that developed during the Chuanzhong paleo-uplift could have provided vents for deep-hydrothermal-fluid upwelling. The redox indices(V/Cr, Ni/Co, and U/Th) and a paleoproductivity proxy(Ni/Al) displayed a significant correlation with the TOC, suggesting that both excellent preservation conditions and high paleoproductivity were the controlling factors for the enrichment of organic matter in the Longmaxi Formation shale. There was no obvious correlation between the clastic influx proxy(Ti/Al) and the TOC due to the extremely low supply of terrigenous debris. The hydrothermal indicator(Fe/Ti) was negatively correlated with the TOC in the Weiyuan area, indicating that hydrothermal activity may have played a negative role in the accumulation of organic matter. This study suggests that the enrichment of organic matter in the Longmaxi Formation marine shale varied according to the paleogeography and sedimentary environment.  相似文献   

开放性地质空间数据库的设计与应用     

李斌  朱筱敏  孟昊  阮壮 《地理空间信息》2012,(1):29-32,36,1,2

使用ArcGIS及Access软件设计了开放性地质空间数据库,高效地管理沉积盆地中的海量地质数据,将地质属性数据、地理空间数据、地质图件等在空间位置上有机地结合起来。实践证明,开放性空间数据库可以有效地管理、交流、分析、提取、更新地质信息,在古地理研究中具有重要的辅助作用。随着地质数据的逐渐增加,其适用性、效率性、直观性愈加显著,古地理研究成果逐步接近准确。  相似文献   

浅析湘南地区锰矿矿源物质来源     

李雪 《湖南地质》2003,22(1):19-23

简述湘南地区表生氧化锰矿矿源层的分布及岩性特征，讨论矿源层与构造及岩相古地理的关系。  相似文献   

Tonian Tectonic-Strata Regions and their Geological Significance in China     

XU Yadong  ZHANG Kexin  HE Weihong  YU Yang  KOU Xiaohu  SONG Bowen  LUO Mansheng  WANG Lijun  MA Zhongjie  YANG Fengli 《《地质学报》英文版》2020,94(4):914-941

The continent of China developed through the coalescence of three major cratons(North China, Tarim and Yangtze) and continental micro-blocks through the processes of oceanic crust disappearance and acceretionary-collision of continental crusts. The strata of the Chinese continental landmass are subdivided into 12 tectonic-strata regions. Based on the composition of geological features among the three main cratons, continental micro-blocks and other major global cratons, their affinities can be preliminarily deduced during the Tonian period, using evidence from sedimentary successions, paleobiogeography, tectonic and magmatic events. The Yangtze and Tarim cratons show that they have close affinities during the assembly-dispersal milestone of the Rodinia Supercontinent. The sedimentary record and magmatic age populations in the blocks suggest that there was a widespread, intensive magmatic event that resulted from a subduction process during ～1000–820 Ma, related to continental rifting around the Yangtze and Tarim cratons. However, they differ greatly from the North China Craton. The continental micro-blocks in the Panthalassic Ocean could have some missing connection with the North China Craton that persisted until the Middle-Late Devonian. In contrast, the Alxa Block showed a strong affinity with the Tarim Craton. The revised Tonian paleogeography of the Rodinia Supercontinent is a good demonstration of how to show the relationship between the main cratons and the continental micro-blocks.  相似文献   

藏北安多地区侏罗纪菊石动物群及其古地理意义   总被引：1，自引：1，他引：1  

伊海生王成善  林金辉时志强 陈兰伍新和  魏钦廉张小青 《地质通报》2005,24(1):41-47

藏北安多地区新发现2套以黑色页岩、深灰色钙质泥岩和泥灰岩为主的舍菊石化石的侏罗纪地层，它们与羌塘地区广泛分布的雁石坪群无论在化石组合或沉积特征方面都明显不同．岗尼乡剖面地层中产太阳菊石科的菊石，主要有Sonninia，Dorsetensia，Witchellia等。、这套地层是双湖地区色哇组的东延部分，时代确定为中侏罗世早中巴柔期114道班剖面中羌姆勒曲组的菊石化石大多归属于Virgatosphinctinae科，计有Aulacosphinctes、Virgatosphinctes等，均为上侏罗统菊石化石的典型分子，产出层位应归于提塘阶中、上部。藏北安多-改则以北一线的侏罗系深水黑色岩系虽不十分连续，但从有化石证据的土阿辛阶到巴柔阶再到提塘阶都有零星出露，它们同属一个沉积相区。侏罗纪时羌塘南部可能存在一套大陆边缘型沉积地层，因此有必要对该区的构造属性和演化历史重新进行解释。  相似文献   

The paleogeographic implications of loess mounds: Laizhou Bay plain     

ZHANG Zu-lu  LIU En-feng  NIE Xiao-hong  WANG Lin 《地理学报》2002,12(2):196-201

The loess mounds are a newly discovered type of landforms on the Laizhou Bay plain south of the Bohai Sea. Research shows that they were formed in the late period of the late Pleistocene when the Bohai Sea was exposed in the period of late Wümu glacial age and changed into plain. As the exposed area is not protected by vegetation, the sediments at the sea bottom are blown and transported southward by strong north winds, and deposit on the coastal plains. As thick loess is accumulated, the loess mound landforms are formed in the direction of down wind.  相似文献   

洋岛,海山碳酸盐岩的沉积特征及其古地理意义   总被引：7，自引：1，他引：7  

张海清  孙晓猛 《地质科技情报》1997,16(1):29-33

高出水面的洋岛和潜伏水下的海山普遍存在于现代地球表面的各大洋中，地质历史中存在的古洋岛和古海山也逐渐为人们所认识。笔者从地形特征，沉积学特征，成岩作用和生物学特征几个方面对洋岛，海山进行了分析，洋岛，海山通常具有洋岛型火山岩基底和碳酸盐盖层的双层式地层结构，具有低分异度，探讨了古洋岛，古海山的鉴别对于再造古海洋，古地理格局的现实意义。  相似文献   

Paleogeographic maps of the Japanese Islands: Plate tectonic synthesis from 750 Ma to the present   总被引：73，自引：1，他引：73  

Shigenori  Maruyama  Yukio  Isozaki  Gaku  Kimura Masaru  Terabayashi 《Island Arc》1997,6(1):121-142

Abstract A series of paleogeographic maps of the Japanese Islands, from their birth at ca 750–700 Ma to the present, is newly compiled from the viewpoint of plate tectonics. This series consists of 20 maps that cover all of the major events in the geotectonic evolution of Japan. These include the birth of Japan at the rifted continental margin of the Yangtze craton ( ca 750-700 Ma), the tectonic inversion of the continental margin from passive to active ( ca 500 Ma), the Paleozoic accretionary growth incorporating fragments from seamounts and oceanic plateaux ( ca 480-250 Ma), the collision between Sino-Korea and Yangtze (250–210 Ma), the Mesozoic to Cenozoic accretionary growth (210 Ma-present) including the formation of the Cretaceous paired metamorphic belts (90 Ma), and the Miocene back-arc opening of the Japan Sea that separated Japan as an island arc (25-15 Ma).  相似文献