Tectono‐sedimentary evolution of the northernmost margin of the NE German Basin between uppermost Carboniferous and Late Permian (Rotliegend)     

H. Rieke  D. Kossow  T. McCann  C. Krawczyk 《Geological Journal》2001,36(1):19-37

The tectono‐sedimentary evolution of the Rotliegend deposits of the northernmost margin of NE German Basin (NEGB) has been analysed on the basis of detailed sedimentary logs of 300 m of core material together with the re‐evaluation of 600 km of seismic lines. Three distinct phases were recognized. During the initial Phase I, basin geometry was largely controlled by normal faulting related to deep‐seated ductile shearing leading to a strong asymmetric shape, with a steep fault‐controlled eastern margin and a gently, dipping western margin. The results of forward modelling along a cross‐section fit the basin geometry in width and depth and reveal a footwall uplift of c. 1000 m. Adjacent to the steep faults, local sedimentation of Lithofacies Type I was confined to non‐cohesive debris flow‐dominated alluvial fans, whereas the gently dipping western margin was dominated by alluvial‐cone sedimentation. During the post‐extensional period (Phase II), cooling of the lithosphere generated additional accommodation space. The sediments of Lithofacies Type II, comprising mainly clast‐supported conglomerates, are interpreted as braided ephemeral stream flow‐surge deposits. Tectonic quiescence and an increase in flood events resulting from wetter climate led to progradation of this facies over the entire region. At the end of this period, the accommodation space was almost completely filled resulting in a level topography. Phase III was controlled by the thermal‐induced subsidence of the southerly located NEGB in post‐Illawarra times. The formerly isolated region tilted towards the SW, thus forming the northern margin of the NEGB during uppermost Havel and Elbe Subgroup times. The sediments of Lithofacies Type III were divided into a marginal sandstone‐dominated environment and a finer‐grained facies towards the SW. The former consists of poorly‐sorted coarse‐grained sandstones of a proximal and medial ephemeral stream floodplain facies. The latter comprise mud flat fines and fine‐grained distal ephemeral stream deposits. The end of the tectono‐sedimentary evolution is marked by the basinwide Zechstein transgression. Copyright © 2001 John Wiley & Sons, Ltd.  相似文献   

新疆阿克苏地区新元古代沉积特征对裂谷发育过程的指示     

刘若涵  何碧竹  焦存礼  蔡志慧  贠晓瑞  彭守涛  郝光明  郭宪璞 《岩石学报》2020,36(10):3225-3242

阿克苏地区地处塔里木克拉通西北部的盆-山结合部位,新元古代地层齐全且发育前寒武纪蓝片岩,保留了新元古代从洋壳俯冲汇聚到陆壳拉张伸展过程的记录,是近年塔里木新元古界研究的热点及重点地区。但阿克苏地区新元古代地层层序和沉积体系的研究较为薄弱,构造对沉积充填的控制作用仍不清楚,由此也制约着对塔里木克拉通初期裂谷发育演化的认识。本文综合地层学、沉积学等多种研究手段,分析阿克苏地区新元古代地层展布及垂向发育特征,将多处实测剖面与钻井-地震剖面结合,构建了阿克苏地区新元古代地层发育序列及空间对比格架。明确了由裂陷控制的沉积相类型及演化：南华纪巧恩布拉克组先后发育冲积扇/扇三角洲、水下-冰川亚相（冰碛岩）及深水陆棚相;尤尔美那克组,早期以陆上-冰川沉积为主,晚期以冲积扇沉积为主;震旦纪苏盖特布拉克组由冲积扇过渡到辫状河三角洲和潮坪相;奇格布拉克组以碳酸盐岩台地沉积为主。通过盆-山构造结合沉积序列分析,确定新元古代经历了三个构造-沉积演化阶段：（1）局限深裂谷发育阶段（南华纪）,充填冲积扇/扇三角洲及深水陆棚相沉积,其中发育两期不同环境的冰川沉积;（2）裂谷扩张期（震旦纪早期）,火山活动强烈,发育冲积扇-辫状河三角洲、潮坪相沉积;（3）坳陷发育期（震旦纪晚期）,广盆浅海环境,发育碳酸盐岩台地。  相似文献   

基于细分行业的中国城市群金融网络演化   总被引：6，自引：1，他引：5  

赵金丽  盛彦文  张璐璐  宋金平 《地理学报》2019,74(4):723-736

基于微观层面的金融企业空间组织关系数据进行宏观层面的金融业空间格局研究是近年来金融地理研究的一个新方向。基于银行、保险及证券三个主流金融行业在1995年、2005年与2015年3个年份的企业网络数据,采用社会网络分析方法,从空间差异、空间过程和空间相互作用3个层次,对各细分行业下的城市群金融网络演化过程进行研究。结果表明：① 银行与保险业视角下,总部企业分布较为集中,且大多中西部城市群内部金融网络较为稀疏,证券业视角下的总部企业分布最为分散,但更替较为频繁。② 银行与保险业视角下的城市群间高层级金融联系较多,证券业视角下则更多为低层级联系,除京津冀、长三角和珠三角为共同的核心网络节点外,银行业其他核心节点集中在沿海地区,保险业则集中在中西部,证券业则呈现出一定的空间均衡性。③ 三行业视角下的城市群发展差异大小及变动趋势不同,证券业视角下的城市群金融资源吸引力差异最大,而总部经济发展差异则最小。④ 各行业地理集中度、市场集中度及影响各行业发展的关键因素的不同,是导致不同行业视角下城市群金融网络演化格局存在差异的主要原因。  相似文献   

Systematic vertical and lateral changes in quality and time resolution of the macrofossil record: Insights from Holocene transgressive deposits,Po coastal plain,Italy     

《Marine and Petroleum Geology》2017

In siliciclastic marine settings, skeletal concentrations are a characteristic feature of transgressive intervals that provide insights into biological and sequence-stratigraphic processes. To investigate taphonomic signatures of transgressive intervals, we analysed three cores along a depositional profile from the high resolution chrono- and stratigraphic framework of the Holocene Po coastal plain, in northern Italy. Coupled multivariate taphonomic and bathymetric trends delineated spatial and temporal gradients in sediment starvation/bypassing, suggesting that quality and resolution of the fossil record vary predictably along the studied depositional profile. Moreover, integration of taphonomic, bathymetric, and fossil density trends across the study area reveals distinctive signatures useful in characterizing facies associations and determining surfaces and intervals of sequence-stratigraphic significance. Within the southern Po plain succession, taphonomic degradation of macroskeletal remains increases from proximal/nearshore to distal/offshore locations. This trend is discernible for both biologically-driven (bioerosion) and physically-driven (e.g., dissolution, abrasion) shell alterations. Compared to the up-dip (most proximal) core, the down-dip core is distinguished by shell-rich lithosomes affected by ecological condensation (co-occurrence of environmentally non-overlapping taxa) and by higher taphonomic alteration. The onshore-offshore taphonomic trend likely reflects variation in sediment-accumulation along the depositional profile of the Holocene Northern Adriatic shelf, with surface/near-surface residence-time of macroskeletal remains increasing down dip due to lower accumulation rates. These results indicate that, during transgressive phases, changes in sea level (base level) are likely to produce down-dip taphonomic gradients across shelves, where the quality and resolution of the fossil record both deteriorate distally. Radiocarbon-calibrated amino acid racemisation dates on individual bivalve specimens and the chronostratigraphic framework for this profile suggest jointly that the high levels of taphonomic degradation observed distally developed over millennial time scales (∼8ky). Whereas in proximal setting overall low taphonomic degradation and geochronologic constrains point to centennial-scale time-averaging during the late transgression phase. Patterns documented in the Holocene transgressive (and lowermost regressive) deposits of the southern Po Plain may be characteristic of siliciclastic-dominated depositional systems that experience high-frequency, base-level fluctuations.  相似文献   

位置主导的空时记录体系架构设计     

关丽  吕雪锋 《测绘科学》2012,(1):104-108

针对传统空间数据记录体系在全球尺度空间数据管理中存在的弊端,如数据图幅范围缺乏大范围或全球统一标准管理、数据跨图幅接边处理复杂等问题,本文构建了一套以空间位置记录为核心、时间为属性、计算机集群为存储模式的空时记录体系。在剖析了传统空间数据记录模式基础上,探讨了空时记录体系的内涵与优势,并基于全球剖分模型及其编码(GeoID编码)着重设计了空时记录体系架构和结构功能,为全球海量空间数据的管理与组织提供了技术参考。  相似文献   

上海地区晚新生代地层划分与沉积环境演化   总被引：1，自引：0，他引：1  

李晓 《上海国土资源》2009,(1)

利用多只见及基岩的钻孔,以岩石地层为基础,结合气候一生物地层、磁性地层和年代地层等多重地层划分,对上海地区晚新生代松散地层进行了系统的划分与对比,厘定了区内第四系下限及各内分地层单位的界限.在系统阐述上新世以来沉积环境演化的基础上,对上海地区晚新生代沉积模式进行了探讨:前期,由上新世一早更新世早期的陆相环境演化为早更新世中期-中更新世的以陆相为主间或为海陆过渡相环境,形成以陆相杂色硬粘土为主的地层序列;后期,晚更新世以来演化为海相和海陆过渡相为主的沉积环境,形成灰色砂、粉土和软粘性土占优势的地层序列.  相似文献   

辽西喀左盆地九佛堂组的划分及相关问题     

王宇林  郭强  李喜海  魏恒飞  王威 《地层学杂志》2009,33(2)

针对辽西九佛堂组存在多种内部划分方案及其他相关问题,通过实测累计达106km的十余条地质剖面,运用岩石地层学、沉积学的基本原理,从喀左盆地九佛堂组识别出5个由凝灰质岩石构成的标志层或层组,并以标志层或层组1、2、4、5的顶界将九佛堂组划分为4个段:一段主要以浅灰、灰白色富凝灰质岩石为特征,砂岩、砾岩比例大;二段以浅灰、深灰色粉砂岩、泥岩为主,部分地段夹油页岩、砂岩、砾岩;三段以褐灰色泥质粉砂岩、深灰及绿灰色粉砂质泥岩为主,根据由标志层或层组,此段又可分为2个亚段,其中上亚段含有工业意义较大的油页岩;四段主要由浅灰、灰白色粉砂岩、黄灰色砂岩、绿灰色泥岩构成。在此基础上,讨论了凝灰质沉积造成大量生物死亡这一与火山活动相关的事件,认为盆地不同地段同期沉积的碎屑岩和部分泥质岩受源区母岩类型控制致使颜色存在差异。沿用前人意见将九佛堂组与沙海组的界线放在标志层或层组5的顶界。  相似文献   

西南地区气候季节划分及特征分析     

徐晓  肖天贵  麻素红 《四川气象》2010,(1):35-40

本文运用聚类分析方法对西南地区进行分区讨论,研究了各区域的气候季节及其变化特征。我国西南地区5个区域夏季和秋季的分配基本一致,而冬春两季差异明显;而降水场和温度场四季划分也有一定相关和相异性,均按照云南区-川西高原区-贵州区-四川盆地区-川东区的顺序逐级递减。  相似文献   

A new natural gamma radiation measurement system for marine sediment and rock analysis     

M.A. VasilievP. Blum  G. ChubarianR. Olsen  C. BennightT. Cobine  D. FacklerM. Hastedt  D. HouptZ. Mateo  Y.B. Vasilieva 《Journal of Applied Geophysics》2011,75(3):455-463

A new high-efficiency and low-background system for the measurement of natural gamma radioactivity in marine sediment and rock cores retrieved from beneath the seabed was designed, built, and installed on the JOIDES Resolution research vessel. The system includes eight large NaI(Tl) detectors that measure adjacent intervals of the core simultaneously, maximizing counting times and minimizing statistical error for the limited measurement times available during drilling expeditions. Effect to background ratio is maximized with passive lead shielding, including both ordinary and low-activity lead. Large-area plastic scintillator active shielding filters background associated with the high-energy part of cosmic radiation. The new system has at least an order of magnitude higher statistical reliability and significantly enhances data quality compared to other offshore natural gamma radiation (NGR) systems designed to measure geological core samples. Reliable correlations and interpretations of cored intervals are possible at rates of a few counts per second.  相似文献   

前陆盆地沉降机理和地层模型   总被引：2，自引：2，他引：0  

杨永泰 《岩石学报》2011,27(2):531-544

前陆盆地形成的主要原因是造山带负载导致的岩石圈挠曲。逆冲作用造成地壳增厚,造山带的巨大质量又导致下部岩石圈的区域均衡沉降,从而临近和平行于造山带发育了凹陷。另外,前陆盆地的演化也受到沉积物供应、盆地内沉积物扩散能力、岩石圈强度、造山带逆冲速率、全球海平面变化、和俯冲有关的动力沉降及俯冲负载等众多其它因素的影响。本文阐述了这些因素与前陆盆地沉降的关系,介绍了与幕式逆冲有关的地层模型和欠补偿-过补偿地层模型。希望本文能够对中国西北地区前陆盆地的研究起到一定的借鉴意义。  相似文献