试从土壤物质迁移与积累论亚热带北界的划分--以河南省伏牛山为例

对伏牛山中段南坡不同海拔高度7 个土壤剖面进行了野外调查和室内土壤理化分析,选择土壤氧化物迁移系数、硅铝铁率、活性铁与全铁之比、活性锰与全锰之比、Ba值、β值等指标,运用聚类分析等方法,从土壤物质迁移和积累角度深入探讨了河南省伏牛山南坡亚热带北界的划分。研究结果表明,该界线大约在海拔950 m左右。     

慢速扩张洋脊上的快速裂谷扩展

慢速扩张洋脊上的快速裂谷扩展ＭａｒｔｉｎＣＫ等２０年前就已经认识到了沿着洋中脊扩张轴的裂谷扩展。一般说来这一过程是随着两个扩张段之间的水平断错沿洋脊走向的移动,一个扩张段吞蚀另一扩张段而加长的过程。这个移动留下了一些倾斜于脊轴的假断层。测量扩展脊...     

<海洋地质与第四纪地质>论文分支学科分布的统计及几点启迪

科技期刊,特别是专业性比较强的学术期刊,衡量它是否具有较高的学术理论水平和应用价值,能否迅速转化为生产力,所登载文稿的被引用率和检索类刊物的收入率均是重要的评判标准,故深入研究登载论文的引文率的内涵,将有助于把握办刊方向、形成特色、早日步入“名牌”、...     

近海底调查的拖曳式海洋重力仪

目前海洋重力主要为海面和海底测量。海面重力测量受水深影响,观测点远离重力源,其分辨率降低;海底测量分辨率不受水层影响,但由于逐点测量的耗时,其覆盖性较差。我们制作了一个重力测量系统,该系统在近海底具有高分辨率、高速采集重力数据的能力,其探头用船拖曳在海底附近的正上方。     

Analytical Solution for the Transient Response of A Sloping Seabed Induced by A P-Wave Line Source

Many offshore marine structures are built on the seabed that are slightly or considerably sloping. To study the sloping seabed transient response during marine earthquakes, an analytical solution induced by a P-wave line source embedded in the solid is presented. During the derivation, the wave fields in the fluid layer and the semi-infinite solid are firstly constructed by using the generalized ray method and the fluid-solid interface reflection and transmission coefficients.Then, the analytica...     

A Floating Astronomical Time Scale for the Early Late Cretaceous Continental Strata in the Songliao Basin,Northeastern China

A continuous terrestrial succession was recovered from the Songke-2(SK-2) borehole in the Songliao Basin, Northeastern China. This borehole provides a unique material for further research on the continental paleoclimate during Cretaceous greenhouse period, following a series of achievements of the Songke-1(SK-1) core. In this study, thorium(Th) logging data were chosen as a paleoclimate proxy to conduct a detailed cyclostratigraphic analysis. The Th series varies quasi-periodically; power spectra and evolutionary fast Fourier transformation(FFT) analysis reveal significant cycles in the Quantou(K2 q), Qingshankou(K2 qn), Yaojia(K2 y) and Nenjiang(K2 n) formations. The ratio of cycle wavelengths in these stratigraphic units is approximately 20:5:2:1, corresponding to long orbital eccentricity(405 kyr), short orbital eccentricity(100 kyr), obliquity(37 kyr), and precession cycles(22.5 kyr and 18.4 kyr). The durations of the K2 n, K2 y, K2 qn and K2 q are estimated as 6.97, 1.83, 5.30 and 4.52 Myr, respectively, based on the constructed ～18.62 Myr "floating" astronomical time scale(ATS). Comparison of the durations between the SK-1 s and SK-2 boreholes exhibits a slight difference of 0.06 Myr and 0.459 Myr for K2 qn and K2 y. Nevertheless, our ATS of K2 n supports the chronostratigraphic frame constructed by the CA-ID-TIMS data of the SK-1 s borehole. This new "floating" ATS provides precise numerical ages for stratigraphic boundaries, biozones and geological events in the Songliao Basin, and can serve as a basis for correlation of strata and events between marine and terrestrial systems.     

Multi-domain equivalent method for prediction of elastic modulus of complex fractured rock mass

Reliable estimation of deformation and failure behaviors of fractured rock mass is important for practical engineering design. This study proposes a multi-domain equivalent method for fracture network to estimate the deformation properties of complex fractured rock mass. It comprehends both the advantages of the discrete fracture network model and the equivalent continuum model to capture the features of discontinuities explicitly while reducing computational intensity. The complex fracture netw...     

Drought adaptation of Bauhinia faberi var. Microphylla seedlings with dual inoculation of arbuscular mycorrhizal fungi

Bauhinia faberi via. Microphylla(BFM) is an important tree species for vegetation restoration in the dry valley of southwestern China. However, there were few studies on the application of arbuscular mycorrhizal fungi(AMF) in improving the drought adaptation of BFM. In order to investigate the response of BFM to water stress(WS), we tested four inoculation treatments((no AMF, Control), Glomus mosseae(GM), Glomus intraradices(GI), Glomus mosseae + Glomus intraradices(GMI)) in pots, experimented u...     

Ground subsidence mechanism of a filling mine with a steeply inclined ore body

Long-term field monitoring finds that serious surface subsidence can still occur even if the high strength cemented fill method is adopted. Combining the results of numerical simulations with global position system(GPS) monitoring, we took a typical filling mining mine with a steeply inclined ore body as an example, and explored its ground subsidence mechanism. The results show that the ground subsidence caused by the mining of steep ore body is characterized by two settlement centers and a sign...