桂西北喀斯特区常绿落叶阔叶混交林种群种间联结性与相关性   总被引：1，自引：0，他引：1  

韩文衡  李先琨  叶铎  吕仕洪  向悟生  宋同清  曹洪麟 《山地学报》2009,27(6)

通过AC测定、X~2检验、Pearson相关检验和Spearman秩相关检验多种指标,分别测定广西木论国家自然保护区9个乔木优势种群在6种不同尺度取样面积下的种间联结性和相关性.结果表明:在中亚热带石灰岩常绿落叶阔叶混交林内,种间联结性测定的取样面积以64-100 m~2为宜,而在9×9 m~2取样中最能体现优势种群的种问联结性及整个群落的特征;9种优势种组成的36对种对中,有15对存在显著或极显著关联,其中正关联12对,占所有显著或极显著关联对数的80%,占所有种对数的33.33%;负关联3对,占所有关联对数的20%,占所有种对数的8.33%.  相似文献   

浙江江郎山丹霞地貌发育的年代与成因   总被引：9，自引：0，他引：9  

朱诚  彭华  李中轩  俞锦标  李兰  张广胜  朱光耀  欧阳杰  钟宜顺  朱青  周书勤  郑朝贵  周日良  李东  朱雨鸣  吕文  武弘麟 《地理学报》2009,64(1)

江郎山位于华南褶皱系、江山-绍兴深断裂和保安-峡口-张村断裂带之间.白垩纪早期这两大断裂的拉张断陷导致峡口盆地的形成,随之主要有下白垩统永康群馆头组(K1g)、朝川组(K1c)和方岩组(K1f)在盆地中的沉积.白垩纪晚期上述两大断裂发生强烈挤压活动,峡口盆地逐渐隆升.新生代以来,峡口盆地在构造抬升中,产生大量张断裂和节理,加速了对岩体的切割,以及岩体被切割后的崩塌,导致了丹霞地貌的发育.江郎山丹霞地貌申报世界自然遗产的主要依据是其特有的壮观而独特的老年期孤峰-巷谷以及生动而逼真的象形石丹霞地貌特征、独特的地台活化现象与重要的岩石学科学研究意义以及该区特有的重要事件地层学和古生物学研究的科学意义.本文根据对江郎山亚峰垂直贯穿于丹霞地貌岩层永康群中辉绿岩脉标本K-Ar法的测年,揭示了当地峡口红层盆地抬升的时代为晚白垩世77.89±2.6Ma BP(K2),这也是我国目前丹霞地貌研究中所测得的可靠年代学数据.  相似文献   

Crust Shortening of the Daliangshan Tectonic Zone in the Cenozoic Era and Its Implications     

Chen Changyun    He Honglin 《中国地震研究》2009,23(1):68-77

The Daliangshan tectonic zone is a rhombic area to the east of the Anninghe and Zemuhe fault zones in the middle segment of the Xianshuihe-Xiaojiang fault system along the southeast margin of the Qinghai-Xizang (Tibet) Plateau. Since the Cenozoic era, the neotectonic deformation in the Daliangshan tectonic zone has presented not only sinistral slip and reverse faulting along the Daliangshan fault zone, but also proximate SN-trending crust shortening. It is estimated that the average crust shortening in the Daliangshan tectonic zone is 10.9±1.6 km, with a shortening rate of 17.8±2.2% using the method of balanced cross-sections. The crust shortening from folding occurred mainly in the Miocene and the Pliocene periods, lasting no more than 8.6 Ma. Based on this, a crust shortening velocity of 1.3±0.2 mm/a can be estimated. Compared with the left offset along the Daliangshan fault zone, it is recognized that crust shortening by folding plays an important part in transferring crustal deformation southeastward along the Xianshuihe-Xiaojiang fault system.  相似文献   

2014年景谷地震震中附近地裂缝成因初析   总被引：2，自引：1，他引：1  

石峰  何宏林  袁仁茂  任治坤  韩非  常祖峰  李西 《震灾防御技术》2014,9(4):782-789

2014年10月7日云南省景谷县发生了M_s6.6级地震,震中附近出现了一系列的地裂缝。本文通过对这些地裂缝的实地调查,结合震源机制、余震分布、烈度分布等其它信息,综合分析探讨了这些地裂缝的成因。结果显示,这些地裂缝都是斜坡在地震的震动影响下,由于重力作用而形成的。在此基础上,本文还深入讨论了不同裂缝的形成机制和模型,为以后甄别地裂缝成因提供了良好的范例。  相似文献   

Development of Two New Copper Isotope Standard Solutions and their Copper Isotopic Compositions          下载免费PDF全文

Honglin Yuan  Wengting Yuan  Zhian Bao  Kaiyun Chen  Fang Huang  Shengao Liu 《Geostandards and Geoanalytical Research》2017,41(1):77-84

In this study, two new laboratory reference solutions for testing Cu isotopic composition were established and investigated. Two commercially available pure copper products, copper plate and copper wire, were dissolved in 1000‐ml Teflon^® bottles, to produce 200 μg ml^?1 stock solutions (hereafter referred to as NWU‐Cu‐A and NWU‐Cu‐B), and cryogenically stored. The Cu isotopic compositions of the two samples were determined in three different laboratories using multi‐collector inductively coupled plasma‐mass spectrometry, and the Cu isotopic compositions obtained from the standard‐sample bracketing method were consistent within the two standard deviation (2s) range. The Cu isotopic compositions of the NWU‐Cu‐A and NWU‐Cu‐B standard solutions were δ⁶⁵Cu = +0.91 ± 0.03‰ (2s, n = 42) and δ⁶⁵Cu = ?0.05 ±0.03‰ (2s, n = 49), respectively, relative to the reference material NIST SRM 976.  相似文献   

Spatio-temporal variation of photosynthetically active radiation in China in recent 50 years     

ZHU Xudong  HE Honglin  LIU Min  YU Guirui  SUN Xiaomin  GAO Yanhua 《地理学报》2010,20(6):803-817

Based on long-term measurement data of weather/ecological stations over China, this paper calculated and produced annually- and seasonally-averaged Photosynthetically Active Radiation (PAR) spatial data from 1961 to 2007, using climatological calculations and spatialization techniques. The spatio-temporal variation characteristics of annually- and seasonally-averaged PAR spatial data over China in recent 50 years were analyzed with Mann-Kendall trend analysis method and GIS spatial analysis techniques. The results show that: (1) As a whole, the spatial distribution of PAR is complex and inhomogeneous across China, with lower PAR in the eastern and southern parts of China and higher PAR in the western part. Mean annual PAR over China ranges from 17.7 mol m-2 d-1 to 39.5 mol m-2 d-1. (2) Annually- and seasonally-averaged PAR of each pixel over China are averaged as a whole and the mean values decline visibly with fluctuant processes, and the changing rate of annually-averaged PAR is –0.138 mol m-2 d-1/10a. The changing amplitudes among four seasons are different, with maximum dropping in summer, and the descending speed of PAR is faster before the 1990s, after which the speed slows down. (3) The analysis by each pixel shows that PAR declines significantly (α=0.05) in most parts of China. Summer and winter play more important roles in the interannual variability of PAR. North China is always a decreasing zone in four seasons, while the northwest of Qinghai-Tibet Plateau turns to be an increasing zone in four seasons. (4) The spatial distributions of the interannual variability of PAR vary among different periods. The interannual variabilities of PAR in a certain region are different not only among four seasons, but also among different periods.  相似文献   

青海玉树M_S7.1级地震地表破裂带的遥感影像解译   总被引：1，自引：1，他引：0  

石峰  何宏林  张英 《震灾防御技术》2010,5(2):220-227

2010年4月14日青海省玉树发生MS7.1级地震,造成严重的人员伤亡和重大的经济损失。除组织现场快速震害评估和地表破裂带调查外,利用高分辨率卫星影像解译是迅速给出初步震害评估和同震地表破裂的位置和展布的最佳途径。本文通过对震前、震后高分辨率SPOT卫星影像的对比,解译出了12km长的同震地表破裂带,其在影像上主要表现为线性阴影和色彩变化。地表破裂带位置和先存的断层、老破裂带位置一致,说明青海玉树地震属于原地复发型地震。同时,解译结果也得到了来自野外实地调查结果的验证,证明了遥感解译的可信性和及时性。但解译破裂长度远小于实际破裂长度,也说明了基于2.5m分辨率的SPOT卫星影像的遥感解译存在较大的局限性。  相似文献   

辽河盆地新生代构造演化模式   总被引：7，自引：1，他引：6  

陈正乐  马寅生  王小凤  吴铁生  武红岭  殷秀兰  陈宣华  霍光辉  王庆丰  郑治宇  兰秀峰 《地质力学学报》1999,5(2):83-89

辽河盆地新生代火山岩的分布规律和岩石学特征表明：辽河盆地新生代的构造环境的为大陆裂谷。地壳深部资料显示了辽河地区存在上地幔隆起,它控制了浅部构造的发育。而辽河盆地新生代断裂构造组合,反演出辽河盆地新生代４期的构造应力作用方式。为此,笔者将造山和成盆作用纳入统一的动力学机制,提出了辽河盆地新生代构造演化的动力学模式。  相似文献   

喀斯特峡谷成因及数学模型研究——以猫跳河、六冲河为例   总被引：2，自引：1，他引：1  

肖鸿林  邹成杰 《中国岩溶》1997,16(2):105-112

喀斯特峡谷,是喀斯特地区由河流的侵蚀、溶蚀和崩塌作用共同塑造的一种特殊地貌类型,它的发生与发展,与岩石性质、河床水力比降、流量等各因素密切相关。峡谷的发育和存在,对水利水电建设具有重要意义。本文主要从水文地貌物理场观点出发,分析喀斯特峡谷形态与上述各因素的相关关系,并建立一定的数学模型,为喀斯特峡谷的研究尝试一种新的研究途径   相似文献   

江西早二叠世晚期—晚二叠世早期的岩相古地理   总被引：2，自引：0，他引：2  

陈钟惠  葛立刚  武法东  张守良 《现代地质》1997,11(3):283

摘　要　根据地层学研究的新进展‚将原乐平组的官山段和下老山段划归茅口阶‚编制了这 一时期的沉积断面图‚并对这一时期的沉积史进行了阐述。  相似文献