[Objective] This paper aimed at revealing the rules of phenotypic variation of Leymus chinensis in Zhalong wetlands and providing the scientific and theoretical bases for devising protection strategies of Leymus chine...[Objective] This paper aimed at revealing the rules of phenotypic variation of Leymus chinensis in Zhalong wetlands and providing the scientific and theoretical bases for devising protection strategies of Leymus chinensis populations in Zhalong National Nature Reserve.[Method] Four phenotypic traits of five Leymus chinensis populations in Zhalong Wetlands were comparison and analysis using principal component analysis method and UPGMA cluster analysis method.[Result] There were significant differences among the four phenotypic traits of five populations,the order of coefficients of variation were node number〉plant height〉leaf width〉leaf length;the order of variation degrees of the populations from large to small was KQH,MD,JZ,ZK,TTG population.Results of principal component analysis suggested that the four traits were all factors led to the phenotypic differences among the populations of Leymus chinensis.Leymus chinensis of five populations were divided into three groups by cluster analysis,MD,JZ and TTG were classified as one group,KQH and ZK population were individually classified as one group.[Conclusion] Leymus chinensis had large-scale phenotypic variations and showed strong adaptability to different habitats,which was very important for selection,breeding of fine varieties and germplasm conservation.展开更多
The preferred orientation of clay minerals dominates the intrinsic anisotropy of shale. We introduce the clay lamination （CL） parameter to the Backus averaging method to describe the intrinsic shale anisotropy induc...The preferred orientation of clay minerals dominates the intrinsic anisotropy of shale. We introduce the clay lamination （CL） parameter to the Backus averaging method to describe the intrinsic shale anisotropy induced by the alignment of clay minerals. Then, we perform the inversion of CL and the Thomsen anisotropy parameters. The direct measurement of anisotropy is difficult because of the inability to measure the acoustic velocity in the vertical direction in boreholes and instrument limitations. By introducing the parameter CL, the inversion method provides reasonable estimates of the elastic anisotropy in the Longmaxi shale. The clay content is weakly correlated with the CL parameter. Moreover, the parameter CL is abnormally high at the bottom of the Longmaxi and Wufeng Formations, which are the target reservoirs. Finally, we construct rock physics templates to interpret well logging and reservoir properties.展开更多
89 Au geochemical anomalies are delineated by using 1/200000 regional geochemical exploration data. By researching regional geochemical characteristics and the relationship with the geological background, the author p...89 Au geochemical anomalies are delineated by using 1/200000 regional geochemical exploration data. By researching regional geochemical characteristics and the relationship with the geological background, the author points out that： the main factors causing high background of Au geochemical anomalies are Gaixian and Dashiqiao formation of Liaohe group, intrusions of Mesozoic intermediate-acid intrusive rocks. The elements combination types of typical anomalies are determined by using factorial analysis,cluster analysis and other mathematical methods with the combination of elements association in typical anomalies：the composite anomaly of Baiyun gold deposits is Au-As-Sb, Maoling gold deposit is Au-As- Bi-Mo, Wulong gold deposits is Au-As-Bi-W, Xiaotongjiapuzi gold deposit is Au-As-Bi-Mo-Sb. By using multivariate statistical analysis method,62 ore-caused anomaly are preferred in 89 Au geochemical anomalies delineated. On this basis, the 62 anomalies are divided into 4 kinds of anomaly types reference to elements combination types of typical anomalies,the classification results of ore-caused anomalies are： 4 geochemical anomalies of Baiyun type,36 geochemical anomalies of Maoling type,11 geochemical anomalies of Wulong type, 11 geochemical anomalies of Xiaotongjapuzi type. According to the results, the prospecting direction is provided for the futme of gold exploration.展开更多
The identification of fractures is of great importance in gravity and magnetic data processing and interpretation.In this study,four fracture identification methods are applied,and widely used in processing and analys...The identification of fractures is of great importance in gravity and magnetic data processing and interpretation.In this study,four fracture identification methods are applied,and widely used in processing and analysis of the gravity anomaly,including vertical second derivative method,tilt derivative method,theta map method and normalized differential method,for gravity data acquired in a given area in Heilongjiang.By comparing the distribution of the zero contour or maximum contour,we summarize the application effects,and both advantages and disadvantages of each method.It is found that tilt derivative method and normalized differential method provide better effects than other two methods:the narrower anomaly gradient belt and higher identification precision of fracture or geological boundary.The inferred fractures and geological boundaries have a great match with the results obtained from geologic map and remote sensing data interpretation.Those study results have definitely provided the theoretical foundation for identifying faults and the geological boundaries.展开更多
In this paper, variations of shear wave splitting in the 2013 Lushan Ms7.0 earthquake sequence were studied. By analyzing shear wave particle motion of local events in the shear wave window, the fast polarization dire...In this paper, variations of shear wave splitting in the 2013 Lushan Ms7.0 earthquake sequence were studied. By analyzing shear wave particle motion of local events in the shear wave window, the fast polarization directions and the delay time between fast and slow shear waves were derived from seismic recordings at eight stations on the southern segment of the Longmenshan fault zone. In the study region, the fast polarization directions show partition characteristics from south to north. And the systematic changes of the time delays between two split shear waves were also observed. As for spatial distribution, the NE fast polarization directions are consistent with the Longmenshan fault strike in the south of focal region, whereas the NW fast direction is parallel to the direction of regional principal compressive stress in the north of focal region. Stations BAX and TQU are respectively located on the Central and Front-range faults, and because of the direct influence of these faults, the fast directions at both stations show particularity. In time domain, after the main shock, the delay times at stations increased rapidly, and decreased after a period of time. Shear-wave splitting was caused mostly by stress-aligned microcracks in rock below the stations. The results demonstrate changes of local stress field during the main shock and the aftershocks. The stress on the Lushan Ms7.0 earthquake region increased after the main shock, with the stress release caused by the aftershocks and the stress reduced in the late stage.展开更多
基金Supported by National Natural Science Foundation of China(40971053)~~
文摘[Objective] This paper aimed at revealing the rules of phenotypic variation of Leymus chinensis in Zhalong wetlands and providing the scientific and theoretical bases for devising protection strategies of Leymus chinensis populations in Zhalong National Nature Reserve.[Method] Four phenotypic traits of five Leymus chinensis populations in Zhalong Wetlands were comparison and analysis using principal component analysis method and UPGMA cluster analysis method.[Result] There were significant differences among the four phenotypic traits of five populations,the order of coefficients of variation were node number〉plant height〉leaf width〉leaf length;the order of variation degrees of the populations from large to small was KQH,MD,JZ,ZK,TTG population.Results of principal component analysis suggested that the four traits were all factors led to the phenotypic differences among the populations of Leymus chinensis.Leymus chinensis of five populations were divided into three groups by cluster analysis,MD,JZ and TTG were classified as one group,KQH and ZK population were individually classified as one group.[Conclusion] Leymus chinensis had large-scale phenotypic variations and showed strong adaptability to different habitats,which was very important for selection,breeding of fine varieties and germplasm conservation.
基金supported by the Foundation of State Key Laboratory of Shale Oil and Gas Enrichment Mechanisms and Effective Development(No.G5800-16-ZS-KFZY002)the NSFC and Sino PEC Joint Key Project(No.U1663207)the National Natural Science Foundation of China(No.41404090)
文摘The preferred orientation of clay minerals dominates the intrinsic anisotropy of shale. We introduce the clay lamination （CL） parameter to the Backus averaging method to describe the intrinsic shale anisotropy induced by the alignment of clay minerals. Then, we perform the inversion of CL and the Thomsen anisotropy parameters. The direct measurement of anisotropy is difficult because of the inability to measure the acoustic velocity in the vertical direction in boreholes and instrument limitations. By introducing the parameter CL, the inversion method provides reasonable estimates of the elastic anisotropy in the Longmaxi shale. The clay content is weakly correlated with the CL parameter. Moreover, the parameter CL is abnormally high at the bottom of the Longmaxi and Wufeng Formations, which are the target reservoirs. Finally, we construct rock physics templates to interpret well logging and reservoir properties.
文摘89 Au geochemical anomalies are delineated by using 1/200000 regional geochemical exploration data. By researching regional geochemical characteristics and the relationship with the geological background, the author points out that： the main factors causing high background of Au geochemical anomalies are Gaixian and Dashiqiao formation of Liaohe group, intrusions of Mesozoic intermediate-acid intrusive rocks. The elements combination types of typical anomalies are determined by using factorial analysis,cluster analysis and other mathematical methods with the combination of elements association in typical anomalies：the composite anomaly of Baiyun gold deposits is Au-As-Sb, Maoling gold deposit is Au-As- Bi-Mo, Wulong gold deposits is Au-As-Bi-W, Xiaotongjiapuzi gold deposit is Au-As-Bi-Mo-Sb. By using multivariate statistical analysis method,62 ore-caused anomaly are preferred in 89 Au geochemical anomalies delineated. On this basis, the 62 anomalies are divided into 4 kinds of anomaly types reference to elements combination types of typical anomalies,the classification results of ore-caused anomalies are： 4 geochemical anomalies of Baiyun type,36 geochemical anomalies of Maoling type,11 geochemical anomalies of Wulong type, 11 geochemical anomalies of Xiaotongjapuzi type. According to the results, the prospecting direction is provided for the futme of gold exploration.
文摘The identification of fractures is of great importance in gravity and magnetic data processing and interpretation.In this study,four fracture identification methods are applied,and widely used in processing and analysis of the gravity anomaly,including vertical second derivative method,tilt derivative method,theta map method and normalized differential method,for gravity data acquired in a given area in Heilongjiang.By comparing the distribution of the zero contour or maximum contour,we summarize the application effects,and both advantages and disadvantages of each method.It is found that tilt derivative method and normalized differential method provide better effects than other two methods:the narrower anomaly gradient belt and higher identification precision of fracture or geological boundary.The inferred fractures and geological boundaries have a great match with the results obtained from geologic map and remote sensing data interpretation.Those study results have definitely provided the theoretical foundation for identifying faults and the geological boundaries.
基金supported by the National Natural Science Foundation of China (Grant Nos. 40904023, 41274063 and 41174070)Scientific Investigation of April 20, 2013 M7.0 Sichuan Lushan Earthquake
文摘In this paper, variations of shear wave splitting in the 2013 Lushan Ms7.0 earthquake sequence were studied. By analyzing shear wave particle motion of local events in the shear wave window, the fast polarization directions and the delay time between fast and slow shear waves were derived from seismic recordings at eight stations on the southern segment of the Longmenshan fault zone. In the study region, the fast polarization directions show partition characteristics from south to north. And the systematic changes of the time delays between two split shear waves were also observed. As for spatial distribution, the NE fast polarization directions are consistent with the Longmenshan fault strike in the south of focal region, whereas the NW fast direction is parallel to the direction of regional principal compressive stress in the north of focal region. Stations BAX and TQU are respectively located on the Central and Front-range faults, and because of the direct influence of these faults, the fast directions at both stations show particularity. In time domain, after the main shock, the delay times at stations increased rapidly, and decreased after a period of time. Shear-wave splitting was caused mostly by stress-aligned microcracks in rock below the stations. The results demonstrate changes of local stress field during the main shock and the aftershocks. The stress on the Lushan Ms7.0 earthquake region increased after the main shock, with the stress release caused by the aftershocks and the stress reduced in the late stage.
