Multi‐scale analysis of a migrating submarine channel system in a tectonically‐confined basin: The Miocene Gorgoglione Flysch Formation,southern Italy     

Claudio I. Casciano  Marco Patacci  Sergio G. Longhitano  Marcello Tropeano  William D. McCaffrey  Claudio Di Celma 《Sedimentology》2019,66(1):205-240

The Miocene Gorgoglione Flysch Formation records the stratigraphic product of protracted sediment transfer and deposition through a long‐lived submarine channel system developed in a narrow and elongate thrust‐top basin of the Southern Apennines (Italy). Channel‐fill deposits are exposed in an outcrop belt approximately 500 m thick and 15 km long, oriented oblique to the palaeoflow, which was roughly south‐eastward. These exceptional exposures of channel‐fill strata allow the stacking architectures and the evolution of the channel system to be analyzed at multiple scales, enabling the effects of syn‐sedimentary thrust tectonics and basin confinement on the depositional system development to be deciphered. Two end‐member types of elementary channel architecture have been identified: high‐aspect‐ratio, weakly‐confined channels, and low‐aspect‐ratio, incisional channels. Their systematic stacking results in a complex pattern of seismic‐scale depositional architectures that determines the stratigraphic framework of the deep‐water system. From the base of the succession, two prominent channel complex sets have been recognized, namely CS1 and CS2, consisting of amalgamated incisional channel elements and weakly‐confined channel elements. These channelized units are overlain by isolated incisional channels, erosional into mud‐prone slope deposits. The juxtaposition of different channel architectures is interpreted to have been governed by regional thrust‐tectonics, in combination with a high subsidence rate that promoted significant aggradation. In this scenario, the alternating ‘in sequence’ and ‘out of sequence’ tectonic pulses of the basin‐bounding thrusts controlled the activation of coarse‐clastic inputs in the basin and the resulting stacking architectures of channelized units. The tectonically‐driven confinement of the depositional system limited the lateral offset in channel stacking, preventing large‐scale avulsions. This study represents an excellent opportunity to analyze the stratigraphic evolution of a submarine channel system in tectonically‐active settings from an outcrop perspective. It should find wide applicability in analogous depositional systems, whose stratigraphic architecture has been influenced by tectonically‐controlled lateral confinement and associated lateral tilting.  相似文献   

时序InSAR断层活动性观测研究进展及若干问题探讨   总被引：5，自引：2，他引：3       下载免费PDF全文

屈春燕  单新建  张国宏  徐小波  宋小刚  张桂芳  刘云华 《地震地质》2014,36(3)

基于大量SAR数据的时序InSAR技术已被广泛应用于断裂带震间长期缓慢地壳形变的观测研究,文中对现有多种时序InSAR方法(如Stacking,PSInSAR,SBAS等)的基本原理和技术特点进行了概括总结。采用PSInSAR技术,利用2003—2010年的17景降轨ENVISAT/ASAR数据,在海原断裂带中段开展了震间地壳形变观测的实验研究,获得了海原断裂中段的跨断层InSAR形变速率场整体图像,显示了约5mm/a的左旋走滑运动速率,与GPS和地质学研究基本一致。在此基础上,对时序InSAR断层活动性观测研究中的若干问题,如LOS形变速率与目标断层走向的关系、LOS形变速率与跨断层观测宽度的关系、LOS形变速率与GPS等其他形变速率的关系以及LOS形变速率场揭示的断层相互作用及断层滑动方式等进行了分析探讨。这些将为进一步推进InSAR构造变形监测研究提供参考。  相似文献   

福建地区环境噪声瑞利波群速度层析成像   总被引：2，自引：1，他引：1  

梁富华  金星  李军  王士成  陈超贤  王紫燕 《中国地震》2012,28(1):22-32

本文利用福建、广东、江西和浙江等4省数字地震监测台网中69个宽频带台站2010年4月13日～10月13日的速度型噪声记录和互相关技术,提取两两台站间的瑞利面波格林函数,并利用层析成像技术最终反演获得了福建地区(115.7～120.5°E、23.6～28.35°N)瑞利面波群速度的分布图像。结果表明,利用该方法得到的福建地区周期为3～5s的瑞利面波群速度在2.73～3.17km/s之间,平均速度为2.96km/s。瑞利波群速度横向变化与福建地区地表构造特征和地热异常区分布情况是基本吻合的;该群速度分布图在漳州盆地和福州盆地区域表现出非常明显的低速异常,这主要是因为受到盆地沉积层和高地热的影响;杉岭地块属于山地地形,但由于受到高地热的影响,因此表现为低速异常;永安-玳瑁山地块为山地区,而受到中地热的影响,速度异常表现较为复杂。  相似文献   

利用接收函数研究河北及邻区地壳厚度与泊松比分布特征     

宫猛  张素欣  罗燕  曾祥芳  贾立峰  刘丽 《中国地震研究》2015,29(3):331-340

本文收集了河北及邻区174个宽频地震仪2007年1月到2011年12月记录到的全球范围内体波震级6.0级以上、共488个远震事件的波形资料。利用H-k叠加搜索方法得到河北及邻区143个台站下方接收函数、地壳厚度和泊松比值分布特征。结果表明,河北及邻区地壳厚度具有明显的分块特征并与区域构造背景有较好的相关性,泊松比值在0.25上下变化,与全球的泊松比估计值相当。河北及邻区地壳厚度以太行山山脉为界呈现出东薄西厚的特征并与地表地形起伏呈正相关;山西地震带南北地壳厚度存在明显差异,大同、宁武及安泽盆地地区泊松比值超过0.3;张-渤地震带地壳厚度由东至西逐渐增厚,泊松比值存在较强的横向变化。华北平原地震带呈现出的薄地壳和低泊松比值特征可能与华北克拉通拆沉作用相关联。  相似文献   

秦岭造山带与南北相邻地带远震接收函数与地壳结构   总被引：4，自引：3，他引：1       下载免费PDF全文

司芗  滕吉文  刘有山  马学英  乔勇虎  董兴鹏  宋鹏汉 《地球物理学报》2016,59(4):1321-1334

从2013年3月至2014年11月,我们布设了一条延川—涪陵的流动宽频带地震台阵,剖面由70个流动台站组成,全长约900km,穿越华北克拉通、秦岭—大巴造山带和扬子克拉通东北缘陆内三大构造单元.利用记录到的远震波形资料,提取得到5638个远震P波接收函数,使用H-κ叠加扫描和CCP偏移叠加方法刻划了秦岭造山带与南北相邻地带的地壳厚度、泊松比以及构造界带.研究结果显示,(1)关于地壳厚度:地壳最厚的区域出现在大巴山,地壳厚度集中在47~51km之间,秦岭的地壳厚度相对大巴山较薄,且呈向北减薄趋势,集中在37~46km之间,渭河盆地地壳厚度为本区域最薄地带,在34°N左右处达到最薄为35km,剖面北侧的南鄂尔多斯盆地的地壳厚度变化缓慢,多为44km左右,南侧的四川盆地东北缘的地壳厚度向南缓慢减薄,集中在42~48km之间;(2)关于泊松比:使用接收函数H-κ叠加扫描法得到了沿剖面各台站下方地壳的平均纵、横波速度比VP/VS(κ),进一步计算得到泊松比σ,泊松比具有明显的横向分块特征,秦岭造山带的泊松比明显低于南北两侧区域,其小于0.26的泊松比表征着该区域地壳物质组分主要为酸性岩石,亦即其酸性长英质组分上地壳相对于基性铁镁质组分下地壳较厚,该区域没有高泊松比分布则表明不存在广泛的部分熔融.(3)关于构造界带:秦岭—大巴造山带与扬子克拉通的边界并非在勉略构造带,应向南移至四川盆地的东北缘,华北克拉通和扬子克拉通分踞秦岭—大巴造山带南、北两侧,且分别以较陡倾角向南和相对较缓的倾角向北俯冲于秦岭—大巴造山带之下,使得秦岭—大巴造山带呈不对称状扇形向外扩展与向上抬升的空间几何模型.秦岭和大巴山之间33°N附近存在分界面,两区域地壳厚度与泊松比特征各异.  相似文献   

多道瞬变电磁法(MTEM)虚拟波场提取技术   总被引：5，自引：3，他引：2       下载免费PDF全文

钟华森  薛国强  李貅  智庆全  底青云 《地球物理学报》2016,59(12):4424-4431

多道瞬变电磁法(MTEM)是近年来发展起来的一种新的地球物理勘查技术,其数据采集方式与地震法类似,因此,采用瞬变电磁拟地震解释方法对MTEM数据进行处理解释具有一定的优越性.研究MTEM虚拟波场有效提取方法具有重要意义.在以往奇异值分解法、预条件正则化共轭梯度法两种不同的常规提取方法研究基础上,本文提出采用相关叠加法提取MTEM虚拟波场信息.首先采用预条件正则化共轭梯度法对全时段MTEM数据进行虚拟波场提取,然后采用同种方法对划分的各时间段数据进行虚拟波场提取,最后对全时段提取结果与各个时间段提取结果进行相关性叠加,叠加结果作为最终的提取结果.实测MTEM数据虚拟波场提取结果表明,采用相关叠加法可以得到稳定、光滑的虚拟波场波形曲线,且抗干扰能力强.  相似文献   

华北地区GPS基准站坐标时间序列噪声特征研究     

吴伟伟  孟国杰  伍吉仓 《大地测量与地球动力学》2016,36(8):708-713

利用华北地区GPS连续运行基准站网络2008-08~2013-04观测数据,分析36个基准站坐标时间序列的噪声特征。利用区域堆栈滤波方法对GPS单日解坐标时间序列进行共性误差剔除,使用极大似然估计准则定量估计坐标时间序列的噪声特性,并分析有色噪声对测站计算速度的影响。结果表明,华北地区GPS基准站坐标时间序列的共性误差在N、E和U方向分别约为1 mm、1 mm和3 mm,且共性误差具有类似闪烁噪声的特性;共性误差剔除前,坐标时间序列的噪声特性可以用可变白噪声加闪烁噪声模型或可变白噪声加幂律噪声模型来描述;共性误差剔除后降低了坐标时间序列噪声中闪烁噪声的成分,突出了本地效应部分噪声,坐标时间序列的噪声特性可以用可变白噪声加闪烁噪声和随机漫步噪声模型或可变白噪声加幂律噪声模型来描述;最优噪声模型计算的速度误差比仅考虑可变白噪声所计算的速度误差增大5~8倍;剔除共性误差,可使测站速度的精度获得40%左右的提高。  相似文献   

井-震标定参数分析及薄层标定——以塔里木盆地哈得四油田为例   总被引：2，自引：0，他引：2  

王晓平  王训练  凌云  张红梅  吴琳 《现代地质》2005,19(2):295-302

新疆塔里木盆地哈得四（HD4）油田的主要储层东河砂岩属于薄储层,其厚度小于1/4地震波长,根据地震数据难以分辨储层的顶界和底界。为了利用声波速度对薄储层进行有效的井-震标定,从井-震标定的原理出发,以哈得四油田的井-震标定为例,分析了标定过程中子波的主频、类型和相位及声波速度对合成地震道的影响,同时分析了声波速度与叠加速度转换的层速度之间的差别。提出以参考层为标准,并对声波速度进行微调的薄储层的标定方法。参考层在研究区是一套沉积环境相对稳定、厚度较大的地层,它对应于地震剖面上的一个振幅较强、反射轴连续并易于追踪的反射界面。利用上述方法,以哈得四油田二叠系火成岩及石炭系双峰灰岩为参考层,选取与研究区地震数据吻合性最好的子波,合理地调整声波速度,对哈得四油田的主要储层东河砂岩进行井-震标定,获得了较为理想的效果。  相似文献   

Controls on accumulation of anomalously thick coals: Implications for sequence stratigraphic analysis     

Shuai Wang  Longyi Shao  Dongdong Wang  Jason Hilton  Biao Guo  Jing Lu 《Sedimentology》2020,67(2):991-1013

Coal seams preserve high-resolution records of ancient terrestrial water table (base level) fluctuations in ancient peat accumulations, but little is known about base level change in anomalously thick coal seams. Using the Early Cretaceous 91 m anomalously thick No. 6 coal (lignite) seam in the Erlian Basin (north-east China) as a case study, the origin and evolution of peat accumulation in a continental faulted basin is revealed by sedimentological, sequence stratigraphic and coal petrological analyses. The lignite is dominated by huminite, indicating oxygen-deficient and waterlogged conditions in the precursor mire. Four types of key sequence stratigraphic surfaces are recognized, including paludification, terrestrialization, accommodation-reversal and give-up transgressive surfaces. Vertically, the No. 6 coal seam consists of fourteen superimposed wetting-up and drying-up cycles separated by key sequence stratigraphic surfaces, with each of these cycles having a mean duration of about 156 to 173 kyr. In a high accommodation peat swamp system, the wetting-up cycles are generally characterized by an upward increase in mineral matter and inertodetrinite and an upward decrease in huminite with the paludification surface as their base and the give-up transgressive surface or accommodation-reversal surface as their top, representing a trend of upward-increasing accommodation. In contrast, the drying-up cycles are generally characterized by an upward decrease in mineral matter and inertodetrinite and an upward increase in huminite, with the terrestrialization surface as their base and the accommodation-reversal surface as their top, representing a trend of upward-decreasing accommodation. A multi-phase mire stacking model for accumulation of the coal seam is proposed based on high-frequency accommodation cycles and the stratigraphic relationships between coal and clastic sediments. High-frequency accommodation cycles in the coal are closely related to water table fluctuations in the precursor mires and are driven by high-frequency climate via changes in the intensity and seasonality of precipitation in a relatively stable subsidence regime. Recognition that the No. 6 coal seam is composed of multiple stacked mires has implications for studies addressing palaeoclimatic inferences and genesis of anomalously thick coals seams.  相似文献   

一次典型的区域性降水天气过程分析     

谢东  于莉莉  陈韶华  辛志远  刘亚琴 《内蒙古气象》2011,(5):12-13

高空槽配合低空切变线和地面低压,在渤海水汽通道建立,强烈的辐合上升运动和大气层结不稳定条件下,使锡林郭勒盟南部产生大雨天气。  相似文献