The abnormal distribution of the molecular fossils in the pre-Cambrian and Cambrian: its biological significance   总被引：9，自引：0，他引：9  

张水昌  Maowen Li  边立曾  张保民  王飞宇  何忠华  王大锐 《中国科学D辑(英文版)》2002,45(3):193-200

Dinosteranes and 4-methyl-24-ethylcholestanes are usually to be thought of as biomarkers for dinoflagellates, and 24-norcholestanes and C₂₈steranes for diatom. Therefore, the highest concentrations of these compounds are typically found in strata deposited since the beginning of the Mesozoic. However these compounds appeared widely and abundantly in extracts from organic-rich sediments in the Sinian and Cambrian of the Tarim Basin. This suggests that some of the planktonic algae such as dinoflagellates and diatoms have an earlier origin than the Mesozoic. Some of the remarkable algal fossils observed in the Cambrian, in both well He 4 and the outcrop section of Xiao-Er-Bulak, Tarim Basin, provide possible biological evidence for this kind of inference.  相似文献   

Preliminary study on the relationship between the crust-mantle structure and the formation of Laowangzhai superlarge gold deposit   总被引：2，自引：0，他引：2  

Qiantao Bian  Hongquan She 《中国科学D辑(英文版)》1998,41(6):561-569

The essential shallow-crust structural factors controlling the formation of Laowangzhai gold deposit include favorable tectonic and regional structural site, the release site of a great deal of the earth energy, favorable orecontrolling structure system, abundant and favorable source rocks for gold, ductile shearing, abundant minerogenetic materials source in extensive crust and mantle. And the essential deep-seated crust-mantle structure factors dominating the formation of the ore deposit include intracrustal low-velocity len, high-velocity bodies in the lower part of middle crust and lower crust, the steps on the slope of Moho, connecting site of mantle rises, the crust-mantle transition layer, upwelling of asthenosphere and the low-velocity plume. It is concluded that the fundamental reason that controls the formation of Laowangzhai superlarge gold deposit lies in the coupling between deep and shallow crust-mantle structure factors controlling the formation of the deposit and their coupling with the lithospheric evolution and geological event. Project supported by the National Climbing Plan Programme A-30.  相似文献   

Using piecewise linear interpolations in spherical harmonic analysis     

S. Bian  J. Menz 《Journal of Geodesy》1998,72(7-8):473-481

In this paper an alternative approach to spherical harmonic analysis is investigated which uses piecewise linear interpolations (PLIs) to replace conventional block mean values (BMVs). Detailed formulations for using PLIs in spherical harmonic analysis are systematically developed. Research shows that BMVs give rise to larger errors than PLIs. Error estimations for the two approaches are given, convincingly showing that PLIs yield much better results than BMVs. Many numerical examples are illustrated and numerically show that PLIs are more reliable and applicable than BMVs. Received: 8 October 1996 / Accepted: 6 March 1998  相似文献   

答《关于深海锰结核中“纳米级超微生物化石”的思考和建议》一文   总被引：2，自引：0，他引：2  

林承毅  边立曾 《高校地质学报》1997,3(2):236-240

本文详细讨论了东太平洋深海锰矿结核中新发现的中华微放线菌和太平洋螺球孢菌究竟是不是超微结构，首先，它们是笔者根据形态，结构和元素成分作为超微生物化石进行鉴定的，其次，透射电子显微镜中可以清楚地区分出完整的微生物结构，包括菌丝，孢子，孢囊和菌落等，它们之间的尺寸比例也是适当的，此外，透射电子显微像还揭示，深海锰质叠层石的纹层就是这些超微生物韵律性生长的结果，与滨海叠层中的纹层十分相似，笔者认为，已知微生物的最小尺寸不能作为否定新发现的超微生物化石的依据。本文还讨论了超微生物化石的术语问题。  相似文献   

内蒙狼山霍各乞矿床条带状含铜石英岩成因的讨论   总被引：5，自引：0，他引：5  

孙宝忠  徐贵忠 《岩石学报》1997,13(2):226-232

内蒙霍各乞条带状含铜石英岩的结构、构造、阴极发光、化学常量元素、稀土元素及其所含的电气石的矿物成分、石英包体测温等方面的特点与加拿大沙利文矿床热水沉积和我国大厂热水沉积矿床中的热水沉积岩－条带状硅质岩及电气石岩十分相似，可以证明了霍各乞条带状含铜石英岩为热水沉积成因  相似文献   

青海可可西里大地构造基本特征   总被引：18，自引：1，他引：18       下载免费PDF全文

边千韬  常承法 《地质科学》1997,32(1):37-46

在可可西里地区发现的晚古生代蛇绿混杂岩及不整合于其上的晚二叠世—早三叠世海滩亚相石英砂岩表明此区曾存在过古特提斯洋,早二叠世末古特提斯基本闭合。晚二叠世—早三叠世为相对稳定阶段。中、晚三叠世海侵,沉积了巨厚复理石。三叠纪末—早侏罗世发生了强烈的造山作用,形成造山带,可可西里地区进入陆内演化阶段。  相似文献   

Pelagic Manganese Nodules--A New Type of Oncolites     

Bian Lizeng  Lin Chengyi  Zhang Fusheng  Du De''an  Chen Jianlin  Shen Huadi Department of Earth Sciences Centre for Materiale Analysis  Nanjing University  Jiangsu Second Institute of Oceanography  State Oceanic Administration  Hangzhou  Zhejiang Liu Xinzhu 《《地质学报》英文版》1997,71(1):43-48

Pelagic manganese nodules from the East Pacific Ocean have been studied using polarizing,scanning electron and transmission electron microscopes. It has been revealed that the manganesenodules are composed of cores and stromatolite coatings. The structures and textures of thesenodules are peculiar to oncolite. Consequently, the pelagic manganese nodules are manganeseoncolites. Based on the stromatolites in the coatings, the manganese oncolites from the East Paci-fic Ocean can be divided into two types. One is smooth on surface and dense inside. Its coatingsare composed mainly of Minima. The other has a knobby surface and is loose internally. Itscoatings consist mainly of Admirabilis. The TEM investigation has also revealed that the con-structors of the manganese oncolites are ultra-microbes. The Minima is constructed byMiniactinomyces chinensis sp. nov. and the Admirabilis is built by Spirisosphaerospora pacifica sp.nov.  相似文献   

基于GIS的城市雨水管网优化设计模型研究     

孟令奎  边馥苓  陈晓宁 《武汉大学学报(信息科学版)》1996,(4)

研究了ＧＩＳ技术在城市雨水管网设计中的应用问题，建立了雨水管网设计的相关模型，重点分析了两类直接影响雨水管网工程的计算模型——水力优化计算与指标再优化模型  相似文献   

地形校正中央区求积公式     

边少锋  刘长剑 《测绘学院学报》1996,(1)

利用非奇变换首先将地形校正奇异积分非奇异，其次利用ＮｅｗｔｏｎＣｏｔｅｓ积分，本文推导了几组适用于地形校正中央区积分的求积公式。  相似文献   

GIS环境下污水管网设计流量的快速计算     

孟令奎  边馥苓  刘玉贤 《武汉大学学报(信息科学版)》1997,(1)

针对ＧＩＳ环境下污水管网设计问题，提出了一种快速计算管段设计流量的方法——递归方法。分析了递归的原理、链式表的建立以及递归算法的具体实现等，并以实例阐述了递归计算的各个步骤  相似文献