华南前汛期低空西南急流-锋面暴雨过程初期的中—中间尺度波状降水过程

在华南前汛期低空西南急流一锋面暴雨过程的初期.存在着一种自西南向东北方向传播的中尺度波状雨带或中到中间尺度的波状雨区.波状雨区的波长为20—100公里左右,传播速度为20—45公里/小时,对应的降水周期为1—4小时.波状雨区出现在500百帕槽前、850百帕冷切变线南面和地面锋面的暖区,以及850百帕冷切变南侧低空西南急流移近、加强的过程中.估计这种波状降水可能是暴雨过程中1—4小时的周期性强非地转西南风风速脉动造成的辐合或重力波触发产生的.中尺度波状雨区的持续旺盛发展可能产生新的中到中间尺度雨成冷性切变线雨带,形成强降水和第一个暴雨区.     

Seasonal variation of rain-belts over China

Decadal rainfall data of 228 stations in 1951–1970 and upper-wind records in 1960–1969 published by the Central Meteorological Bureau and relevant provincial organizations are employed in the analysis. It is found that the characteristic features of seasonal variation of the main rain-belts over eastern China to the east of 105°F are quite different from those to the west, over the Qinghai-Xizhang (Tibetan) Plateau. The eastern rain-belts are closely related to the low level flow convergence lines and significantly influenced by the south Asian high and the western Pacific subtropical high.     

青海察尔汗盐湖的盐喀斯特

<正>青海柴达木盆地中的察尔汗盐湖的盐喀斯特晶间卤水中蕴藏着丰富的钾镁盐矿床。本文仅就其现代盐湖盐喀斯特的形态、成因以及盐喀斯特水对一些矿床的成矿意义,谈些粗浅看法。     

Similarity of two Liyang earthquakes

Two moderate earthquakes of magnitudesM _s=5.5 and 6.0 occurred in 1974 and 1979, respectively, in the Liyang region, Jiangsu Province, China. The distance between the two epicenters is less than 20 km and their source mechanisms are very similar. In comparing these two earthquakes, we notice that the similarity of coseismic effects is consistent with a scaling law. The isoseismals of the two earthquakes resemble each other in overall shape but the difference of intensity between pairs of coincident isoseismals is one degree. The precursory seismicity patterns of the two events, such as seismic gaps and preshock swarms, are similar, but do not scale to magnitudes of mainshock. The latter phenomenon may reflect the regional tectonic structure, assuming the entire region to be subjected to the same stress.     

合成斜方辉石系列的红外光谱研究

在30kbar和900℃条件下,用等化学计量氧化物混合物合成了11个斜方辉石系列的样品,并对合成的样品进行了X射线粉晶分析和红外光谱分析。分析结果表明,晶胞参数和红外光谱随化学成分的改变而产生复杂的变化。不仅晶胞参数b和M而且频率ν_(670cm)-1和M之间存在很好的线性相关关系,通过用最小二乘法所拟合的相关方程可容易地测定斜方辉石的成分,但是α和c与M之间只有较差的线性关系,而ν_(450cm)-1和M以及ν_(380cm)-1和M之间并无简单的线性相关关系,这可归因于Fe~(2+)在M_1和M_2位置的有序分布。     

1980年夏季我国天气气候反常和St.Helens火山爆发的影响

1980年5月18日St.Helens火山大爆发,大量火山灰喷入平流层,围绕北半球中纬度带飘浮。在30°N以北我国东部各站晴空直接辐射量(S)从6月上旬开始异常偏低,夏季S达到近二十余年来的最低值,夏季中纬度S的经向梯度异常增大;相应地,西太平洋副高及北侧的季风雨带在7—8月异常偏南,形成了我国严重的北旱南涝以及江淮冷夏等反常天气气候。本文现就此作物理分析。     

S,Pb, C and O isotopic compositions and ore genesis of the strata-bound polymetallic sulfide deposits in central Inner Mongolia,China

The strata-bound Cu−Pb−Zn polymetallic sulfide deposits occur in metamorphic rocks of greenschist phase of the middle-upper Proterozoic Langshan Group in central Inner Mongolia. δ³⁴S values for sulfides range from −3.1‰ to +37.3‰, and an apparent difference is noticed between vein sulfides and those in bedded rocks. For example, δ³⁴S values for bedded pyrite range from +10.6‰ to +20.0‰, while those for vein pyrite vary from −3.1‰ to +14.1‰. δ³⁴S of bedded pyrrhotite is in the range +7.9‰–+23.5‰ in comparison with +6.5‰–+17.1‰ for vein pyrrhotite. The wide scatter of δ³⁴S and the enrichment of heavier sulfur indicate that sulfur may have been derived from H₂S as a result of bacterial reduction of sulfates in the sea water. Sulfur isotopic composition also differs from deposit to deposit in this area because of the difference in environment in which they were formed. The mobilization of bedded sulfides in response to regional metamorphism and magmatic intrusion led to the formation of vein sulfides. δ¹⁸O and δ¹³C of ore-bearing rocks and wall rocks are within the range typical of ordinary marine facies, with the exception of lower values for ore-bearing marble at Huogeqi probably due to diopsidization and tremalitization of carbonate rocks. Pb isotopic composition is relatively stable and characterized by lower radio-genetic lead. The age of basement rocks was calculated to be about 23.9 Ma and ore-forming age 7.8 Ma.²⁰⁷Pb/²⁰⁴Pb−²⁰⁶Pb/²⁰⁴Pb and²⁰⁸Pb/²⁰⁴Pb−²⁰⁶Pb/²⁰⁴Pb plots indicate that Pb may probably be derived from the lower crust or upper mantle. It is believed that the deposits in this region are related to submarine volcanic exhalation superimposed by later regional metamorphism and magmatic intrusion.     

河北平原的浅埋古河道

河北平原埋深8—30m的砂层透镜体,呈一定方向的条带状分布,具有许多河流相沉积标志。相对于地面出露古河道(埋深0—8m)和深部埋藏古河道(埋深60—100m以下),我们称之为浅部埋藏古河道,简称浅埋古河道。     

齐依求金矿中微球粒特征

首次报道齐依求金矿中微球粒的发现，对微球粒形态特征、表面及断面结构、物理特性、矿物组成、化学成分进行分析测试，并就其成因作了初步探讨，认为属宇宙成因。