中国数字地震台网（CDSN）数据文件系统：—CDSN应用系列论文一     

牟其铎 《地震地磁观测与研究》1992,13(3):1-23

中国数字地震台网(CDSN)观测并生成的数字地震资料是开展数字地震学研究必不可少的高质量数据源。为了使科学家们更好地使用这些数据,本文主要从数字地震资料产生出的各个环节、数据结构与格式、数据物理量之间的换算向读者作概括的介绍.希望读者对数字化地震资料的数据文件、数据记录、数据字均能有透彻的理解,从而节省时间和精力,提高资料的使用率。  相似文献   

横断事件:亚洲东部晚新生代的一次重大构造事件   总被引：3，自引：0，他引：3  

陈富斌 《山地学报》1992,(4)

新近研究结果表明,吉尔伯特世与高斯世的界面附近(距今约340万年)存在着一次重大构造事件,主要证据在横断山系,故称横断事件。由它引发我国第四纪断陷盆地的发育与青藏高原的块状隆起,使横断山系新的地貌过程得以起步,从此我国地壳构造演化进入一个崭新的阶段,青藏高原隆起是横断事件以来亚洲大陆新构造运动的代表性显现,建议以该事件为起点的地壳构造运动称为青藏高原运动。  相似文献   

A palaeomagnetic study of some Pleistocene sediments in northern Canada and its bearing on the secular variation of the geomagnetic field     

M. A. H. Hedlin  M. E. Evans 《Geophysical Journal International》1987,90(3):693-703

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中国地层学史上的“历史优先律事件”和“优先律双重标准事件”   总被引：2，自引：1，他引：1       下载免费PDF全文

张守信 《地质科学》2004,39(3):452-456

近10年内,中国地层学史上发生过两件大事:一是“历史优先律事件”,表现为全国地层委员会具体组织并由其副主任程裕淇主编的《中国地层典》,对优先权法则不执行以出版为基础的“出版优先律”而执行不论发表与否仅以“尊重原始命名者”为基础的“历史优先律”;二是“优先律双重标准事件”,在全国地层委员会颁布的《中国地层指南》(修订版)内对优先律搞双重标准。这两个事件均表现对“优先权法则”国际共识内涵的偏离,偏离了以出版为基础的“出版优先律”。尤其不应该的是,当人们对“历史优先律”提出异议后,全国地层委员会不但不及时纠正“历史优先律”的片面观点,相反地却在修订中国地层命名法时,为了给“历史优先律”合法化创造条件,竟然在《中国地层指南》(修订版)内,对优先权搞双重标准。“历史优先律事件”和“优先律双重标准事件”破坏了地层命名法的标准性,颠倒了中国地层命名史,干扰了中国地层名称的管理,是全国地层委员会的失误。  相似文献   

Carbon isotope stratigraphy of Lochkovian to Eifelian limestones from the Devonian of central and southern Europe     

Werner?BuggischEmail author  Ulrich?Mann 《International Journal of Earth Sciences》2004,93(4):521-541

Lower to Middle Devonian carbonates of the Prague Syncline, the Carnic Alps, the Montagne Noire, and the Cantabrian Mountains were investigated for δ¹³C_carb and δ¹³C_org. These values were measured on bulk rocks, selected components and cements. Many carbonates exhibit primary marine values, but some are altered by diagenesis. A δ¹³C curve can be presented for the latest Pridolian to Emsian time interval. Several sharp or broad positive excursions are obvious in the woschmidti-postwoschmidti, sulcatus, kitabicus, Late serotinus, and kockelianus conodont zones. The excursion at the Silurian–Devonian boundary is known worldwide and therefore considered global in nature. Some of the others are described for the first time from central and southern Europe, and their global nature has to be verified by further investigations in other regions. Most excursions relate to and/or started during major regressions whereas sea-level highstands correspond to minimal δ¹³C values. Similar relationships between sea-level changes and δ¹³C have been observed from other early Palaeozoic intervals. The transgressive Chote? (?) and Ka?ák events are marked by positive isotope excursions, this type of combination is usually observed in late Palaeozoic to Cenozoic black shale events.  相似文献   

深圳市高影响天气的风廓线雷达特征   总被引：1，自引：0，他引：1  

陈元昭  彭勇刚  王明洁  陈训来 《广东气象》2010,32(3):12-16

利用深圳多年风廓线雷达观测资料,分析了灰霾、大雾、高温、雷暴、台风、冷空气等高影响天气过程中的风廓线特征。结果表明风廓线雷达作为一种新型的探测工具,能够在垂直方向获取较高时间、空间分辨率的实时资料,为分析、预报预警高影响天气提供了新的资料和观测事实。不同的高影响天气风廓线特征各不相同。灰霾和高温以上空出现东北风为特征:大雾的水平、垂直方向分布与信噪比有关;雷暴等强对流天气具有明显的风垂直切变;热带气旋、西风槽和锋面等移动性天气系统,其风向、风速的垂直分布随时间有明显变化。  相似文献   

Tethyan–Mediterranean organic carbon-rich sediments from Mesozoic black shales to sapropels     

KAY-CHRISTIAN EMEIS  HELMUT WEISSERT† 《Sedimentology》2009,56(1):247-266

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邻近算法在微地震震源位置和一维速度模型同时反演中的应用     

田宵  汪明军  张雄  张伟  周立 《中国地震》2021,37(2):452-462

微地震事件的空间分布可以用来监测水力压裂过程中裂缝的发育情况。因此,震源定位是微震监测中重要的环节。震源定位依赖准确的速度模型,而震源位置和速度模型的耦合易导致线性迭代的同时反演方法陷入局部极小值。邻近算法作为一种非线性全局优化算法,能够最大程度地避免陷入局部最优解。本文将邻近算法应用于单井监测的微震定位和一维速度模型同时反演,首先利用邻近算法搜索一维速度模型,再使用网格搜索方法进行震源定位,并根据定位的走时残差产生新的速度模型,最后通过若干次迭代使其收敛到最优解。理论和实际数据结果均表明该方法能够避免局部最优解,得到较为可靠的震源位置和一维速度模型。  相似文献   

新元古代—寒武纪硫同位素异常事件(Yudomski事件)的起源与结束          下载免费PDF全文

张智礼  孟凡巍  倪培  李慧莉  卓勤功 《盐湖研究》2020,28(4):22-28

新元古代晚期—寒武纪早期是地球历史演化的关键时期,整个生物圈、大气圈和水圈在此期间都发生了巨大的变化,海水成分在其间也发生了明显的变化。而石盐流体包裹体恰恰记录了该时段海水主要离子成分的转变:海水成分从新元古代晚期的“文石海”,快速转化为寒武纪的“方解石海”；同时海水中的碳、锶、硫同位素都发生了剧烈的改变,其中海水硫酸根的硫同位素从新元古代冰期前的20‰左右,迅速升高到新元古代冰期后的35‰左右,甚至可以到45‰,海相蒸发岩沉积中的硫酸盐沉积(主要是石膏、硬石膏)则直接记录了当时海水中硫酸根的硫同位素变化。现有研究表明,新元古代晚期——寒武纪时期的海相蒸发岩沉积记录了当时海洋中存在着地质历史时期最大的硫同位素异常,即“Yudomski事件”。塔里木盆地的寒武纪早期、中期蒸发岩记录了“Yudomski事件”的硫同位素异常高值(35‰左右,甚至更高),表明这一起源于新元古代晚期的同位素异常事件持续到了寒武纪的早期和中期；塔里木盆地奥陶纪早期的蒸发岩、鄂尔多斯盆地奥陶纪中期蒸发岩和美国Williston盆地奥陶纪晚期地层的蒸发岩的硫同位素数据相似,都在+25‰左右则记录了较低的海洋硫同位素值,表明起源于新元古代冰期之后的“Yudomski事件”的硫同位素异常,持续到了寒武纪的中期,而结束于寒武纪的晚期。  相似文献   

Mega-monsoon variability during the late Triassic: Re-assessing the role of orbital forcing in the deposition of playa sediments in the Germanic Basin   总被引：1，自引：0，他引：1  

André Bahr  Gilles Kolber  Stefanie Kaboth-Bahr  Lutz Reinhardt  Oliver Friedrich  Jörg Pross 《Sedimentology》2020,67(2):951-970

The formation of the supercontinent Pangaea during the Permo–Triassic gave rise to an extreme monsoonal climate (often termed ‘mega-monsoon’) that has been documented by numerous palaeo-records. However, considerable debate exists about the role of orbital forcing in causing humid intervals in an otherwise arid climate. To shed new light on the forcing of monsoonal variability in subtropical Pangaea, this study focuses on sediment facies and colour variability of playa and alluvial fan deposits in an outcrop from the late Carnian (ca 225 Ma) in the southern Germanic Basin, south-western Germany. The sediments were deposited against a background of increasingly arid conditions following the humid Carnian Pluvial Event (ca 234 to 232 Ma). The ca 2·4 Myr long sedimentary succession studied shows a tripartite long-term evolution, starting with a distal mud-flat facies deposited under arid conditions. This phase was followed by a highly variable playa-lake environment that documents more humid conditions and finally a regression of the playa-lake due to a return of arid conditions. The red–green (a*) and lightness (L*) records show that this long-term variability was overprinted by alternating wet/dry cycles driven by orbital precession and ca 405 kyr eccentricity, without significant influence of obliquity. The absence of obliquity in this record indicates that high-latitude forcing played only a minor role in the southern Germanic Basin during the late Carnian. This is different from the subsequent Norian when high-latitude signals became more pronounced, potentially related to the northward drift of the Germanic Basin. The recurring pattern of pluvial events during the late Triassic demonstrates that orbital forcing, in particular eccentricity, stimulated the occurrence and intensity of wet phases. It also highlights the possibility that the Carnian Pluvial Event, although most likely triggered by enhanced volcanic activity, may also have been modified by an orbital stimulus.  相似文献