河北宣化土城子组恐龙足迹化石新发现     

鞠书彬  王旭日  董颖  刘义川  季燕南  季强 《地质学报》2022,96(7):2295-2311

本文报道了新近发现于河北宣化地区土城子组的恐龙足迹化石及沉积环境。为确定足迹化石的地质年代、土城子组的沉积环境及足迹化石属种，本文在对恐龙足迹化石层及其上、下地层进行剖面测制、沉积相划分和沉积环境分析的基础上，对化石层上覆凝灰岩层进行了LA- ICPMS锆石U- Pb测年，并对保存较好的足迹化石进行了测量和对比研究工作。研究结果表明，土城子组底部为冲积扇扇中沉积环境，足迹化石上、下地层则表现为河流相沉积环境，而足迹化石的赋存层位形成于滨湖相沉积环境，发育暴露构造并含有大量裸子植物碎屑化石。凝灰岩锆石U- Pb加权平均年龄为152. 3±0. 3 Ma（MSWD=0. 00106），说明化石层位于土城子组一段，时代属于晚侏罗世钦莫利期（Kimmeridgian）中晚期。已发现的足迹化石以兽脚类三趾型足迹为主，包括跷脚龙足迹属（Grallator）、安琪龙足迹属（Anchisauripus）和实雷龙足迹属（Eubrontes），其次为一些疑似蜥脚类恐龙足迹，是华北北缘土城子组中群落丰富度最高的恐龙足迹点，其中一处或许为中国北方面积最大的恐龙足迹点。因此，我们认为宣化- 下花园盆地土城子组一段以河流、湖泊相沉积环境为主，当时裸子植物繁茂，恐龙动物群庞大，偶尔存在火山喷发活动。新发现的宣化恐龙足迹不仅填补了宣化- 下花园地区恐龙足迹化石的空白，也丰富了燕辽地区土城子组生物群的组合面貌，为土城子组内年代地层划分及陆相J/K界线的确定提供了新的证据。  相似文献   

基于FLAC3D数值模拟的老采空区剩余沉降量分析计算—以山东枣庄安博化工项目为例     

臧浩  种衍飞  冯堂武  于树宾  张昌龙 《山东国土资源》2015,31(7)

空区的剩余沉降值计算是采空区地质灾害危险程度一种定量分析的方法,利用FLAC3D直接模拟早期采煤形成的老采空区塌陷状态,计算出老采空区的剩余沉降量。以山东枣庄安博化工项目为例,首先采用物探、钻探手段探测老采空区深度、顶板塌落与破碎状况以及地质地层信息,其次结合岩心试验地质材料参数结果进行FLAC3D模拟,计算自重作用下采空区剩余沉降量,以及加载建筑后老采空区剩余沉降值,对比了传统概率积分法计算沉降值,结果基本一致,说明计算方法是可靠的。最后分析加载应力与破碎带剩余沉降值的数量关系。为老采空区土地稳定性评估以及剩余沉降量的计算方法提供科学依据与借鉴。  相似文献   

“I’m an imaginary figure”: Unravelling the mobility and marginalisation of Scottish Gypsy Travellers     

Sergei Shubin  Kate Swanson 《Geoforum》2010,41(6):919-929

Gypsy Travellers have a long history of marginalisation in Scotland, but their mobility remains an issue of particular contention. Drawing upon a series of interviews with Gypsy Travellers in the North-East of Scotland, this paper uncovers how power and politics permeate discourses on movement to legitimise the spatial ordering of this traditionally nomadic group. The paper begins by exploring the more hidden and subtle aspects of mobility, such as the emotional and imaginative ties to travel. It then shifts to document how Gypsy Travellers’ geographies have been compromised by discriminatory policies and practices, which demonstrate a misunderstanding of the heterogeneity of their mobility. Consequently, increasingly punitive policies have pushed many Gypsy Travellers to abandon their travelling ways to move into “fixed” housing, while others have been forced into states of perpetual motion. The overall goal of the paper is to unravel the discursive constructions of movement in the context of institutionalised power and to document the spatial ordering of Gypsy Travellers’ lives, whose marginality has been legitimised by laws, ideologically sustained and reproduced in policy documents.  相似文献   

First Zircon U‐Pb Ages of the Pigeon Hill Fossil Locality of the Jehol Biota in the Greater Khingan Mountains,Inner Mongolia     

WANG Xuri  JU Shubin  WANG Yang 《《地质学报》英文版》2019,93(4):1142-1145

  相似文献   

Empirical Model of the Location of the Main Ionospheric Trough     

M. G. Deminov  V. N. Shubin 《Geomagnetism and Aeronomy》2018,58(3):348-355

The empirical model of the location of the main ionospheric trough (MIT) is developed based on an analysis of data from CHAMP satellite measured at the altitudes of ~350–450 km during 2000–2007; the model is presented in the form of the analytical dependence of the invariant latitude of the trough minimum Φ_m on the magnetic local time (MLT), the geomagnetic activity, and the geographical longitude for the Northern and Southern Hemispheres. The time-weighted average index Kp(τ), the coefficient of which τ = 0.6 is determined by the requirement of the model minimum deviation from experimental data, is used as an indicator of geomagnetic activity. The model has no limitations, either in local time or geomagnetic activity. However, the initial set of MIT minima mainly contains data dealing with an interval of 16–08 MLT for Kp(τ) < 6; therefore, the model is rather qualitative outside this interval. It is also established that (a) the use of solar local time (SLT) instead of MLT increases the model error no more than by 5–10%; (b) the amplitude of the longitudinal effect at the latitude of MIT minimum in geomagnetic (invariant) coordinates is ten times lower than that in geographical coordinates.  相似文献   

Global Dynamic Model of Critical Frequency of the Ionospheric F2 Layer     

Shubin  V. N.  Deminov  M. G. 《Geomagnetism and Aeronomy》2019,59(4):429-440

Geomagnetism and Aeronomy - A global dynamic model of the F2 layer of the ionosphere GDMF2 is designed to calculate foF2 in both quiet and geomagnetically disturbed conditions. The term...  相似文献   

利用背景噪声反演鄂尔多斯块体及其南缘地区地壳速度结构   总被引：1，自引：0，他引：1  

陈强森  鲍学伟  徐树斌  王良书  徐鸣洁 《高校地质学报》2013,19(3):504-512

文中利用分布在鄂尔多斯块体及其南部周缘地区的53 个宽频带地震固定台站的连续波形记录,采用双台互相关计算 方法由背景噪声提取瑞利波格林函数,经时频分析获得相速度和群速度频散曲线,并分别计算了汾渭地堑、秦岭北缘、鄂 尔多斯块体内部和六盘山地区4 个不同构造区的平均频散曲线,进而反演了各构造区的地壳上地幔一维横波速度结构。结 果显示：地壳厚度在汾渭地堑为34 km,在秦岭北缘地区和鄂尔多斯块体均为40 km,在六盘山地区最厚,达49~50 km;相 应的上地幔顶部横波速度分别为4.20,4.2,4.30 和4.15 km/s;地壳内结构浅部特征差异最大,在地壳中部六盘山地区的速 度较低,下部地壳不同地区的波速较一致。  相似文献   

Successional stages of biological soil crusts and their microstructure variability in Shapotou region (China)   总被引：6，自引：1，他引：5  

Shubin Lan  Li Wu  Delu Zhang  Chunxiang Hu 《Environmental Earth Sciences》2012,65(1):77-88

In order to investigate succession of biological soil crusts (BSCs) and their microstructure variability, we conducted this work in Shapotou revegetation region at the southeast edge of Tengger Deser. The results showed that BSCs generally succeeded as a pathway of “Algae crusts, algae–lichen crusts, lichen crusts, lichen–moss crusts and moss crusts”. Occasionally mosses directly occurred on algae crusts, and BSCs succeeded from algae crusts to moss crusts. Crust vertical stratification was a common phenomenon, from top to bottom an inorganic layer, algae-dense layer and algae-sparse layer were divided in algae crusts; a thallus layer, rhizoid layer and sub-rhizoid layer in lichen crusts; a “stem-leaf” layer, rhizoid layer and sub-rhizoid layer in moss crusts, respectively. The main crust binding organisms varied from filamental cyanobacteria (dominated by Microcoleus) in algae crusts to lichen rhizoids, free-living cyanobacterial filaments and fungal hyphaes in lichen crusts, and to moss rhizoids and fungal hyphaes in moss crusts. The dominant phototrophic organisms varied from Microcoleus (algae) in algae crusts to Collema (lichens) in lichen crusts, and to Bryum (or Didymodon and Tortula; mosses) in moss crusts. Total phototrophic biomass increased while the free-living algal biomass decreased with the succession of BSCs. In addition, exopolysaccharides and fine particles accumulated in the course of development and succession of BSCs, all of which lead to a gradual increase in crust thickness and porosity, while decrease in the bulk density.  相似文献   

新型预制楼盖的装配整体式框架剪力墙结构振动台试验研究   总被引：2，自引：0，他引：2  

郑先超  李青宁  潘树宾  姜维山 《地震工程与工程振动》2013,33(3)

基于发展装配式建筑是实现建筑节能的重要举措,从楼盖要满足平面内刚性的要求,结合实际工程进行了不加后浇面层的新型预制楼盖的中间钢板剪力墙边榀钢框架三层结构模型的振动台试验,并对采用新型预制板和新型连接的装配整体楼盖的面内变形、传递水平地震作用力的性能进行了分析.研究结果表明:采用新型预制板和新型连接的不加后浇面层楼盖的刚性可以保证结构的空间整体性和水平力的有效传递,在高烈度地区可以考虑用不加后浇面层的装配整体式楼盖代替现浇楼盖.  相似文献   

哀牢山中山湿性常绿阔叶林空心树木质残体呼吸作用初步研究   总被引：1，自引：0，他引：1  

张树斌  郑征 《山地学报》2008,26(3)

对云南哀牢山中山湿性常绿阔叶林空心树木质残体雨季和干季的呼吸速率进行测定,并对木质残体呼吸速率与木质密度和含水量之间的相关关系进行比较,分析了呼吸速率对温度的敏感性.结果表明:树干表层木质残体雨季呼吸速率显著高于树干内层和洞内的(p＜0.05),干季三个部位木质残体呼吸速率之间差异不显著(p＞0.05).含水量和呼吸速率存在季节差异,在树干表层和洞内雨季的含水量和呼吸速率显著高于干季的(p＜0.05),而在树干内层季节差异不显著(p＞0.05).三个部位木质残体密度与呼吸速率在雨季显著负相关(p＜0.01),三个部位的含水量和呼吸速率在雨季和干季都显著正相关(p＜0.01);木质残体的温度系数(Q10)大小顺序为:洞内(2.08)＞树干表层(2.01)＞树干内层(1.73),树洞内部木质残体对温度响应最敏感.哀牢山地区干季空心树木质残体较低的含水量和全年温凉的气候条件可能成为该区中山湿性常绿阔叶林空心树木质残体分解重要的限制因子.  相似文献