Compositional conversion of feldspathic phase in granitoids and its application to rock-forming temperature calculation

Based on the data on plagioclase number of granitoids and whole-rock chemical analysis, the author has proposed that the percentage of molecules of albite in the coexisting plagioclase and alkali-feldspar can be obtained by direct conversion through a petro-chemical approach. Then, the result is substituted into the formula of J. A. Whitney and J. C. Stormer, Jr. (1975, 1977) to work out, the temperatures at which the coexisting feldspars crystallized, i.e., the possible rock-forming temperature of granitoids. Rock-forming temperature values computed by this method as described in the present paper are in good agreement with those by other geothermometries.     

大气降水对昆明周围地震活动的调制

本文对比分析了昆明周围地区20余年来的大气降水记录和地震资料,指出旱涝变异确实与地震活动存在着一定的统计联系。其中尤以震前一年洪涝的作用较为突出。在此基础上,提出了一个可预测本区中强地震发生的经验性方法。     

渡口-西昌区域河流冲积层C14年龄与断裂活动最新地质年代研究

研究区地质构造复杂,断裂发育,安宁河、金箐等断裂带第四纪以来强烈活动,并且成为安宁河地震带的发震构造。因此,在工程建设中迫切需要论证地壳稳定性和研究地震活动性。断裂活动年代是分析这两个问题的基础。我们对含淤泥的冲积层做了C¹⁴年龄测试,对典型第四纪断层进行了野外调查,在此基础上完成本文。     

Inhomogeneous features in mel-yu frontal cloud system

The structure of radar echo in stratiform cloud which was found in mei-yu frontal cloud system is generally inhomogeneous, especially in the structure of bright band echoes. The inhomogeneous structure of warm region in stratiform cloud and the shower feature of precipitation are closely related to the inhomogeneous structure of bright band and convective cells embedded in stratiform cloud.During Summer time the mei-yu cloud system is an important precipitating system in the southern part of China. To study its structure is of great significance for weather forecast and understanding the physical processes of cloud and precipitation. Therefore, we have observed mei-yu frontal cloud system by use of 711 type radar (3 cm) and airplane at Tunxi, Anhui Province since 1979. It was found that the structure of stratiform cloud, especially the structure of its warm region appears to be inhomogeneous1),2). This is a significant feature of cloud structure in mei-yu frontal cloud system. In this paper, we shall further analyse this inhomogeneous structure of stratiform cloud and study its effect on the precipitation.     

非矩形网格上的车贝雪夫展开

本文指出:在任意不规则的非矩形二维网格上,若采用两步展开的做法,即首先逐行展开,再按列展开就可以对在该网格上给定的函数实现二维车贝雪夫多项式展开。这一推广在实用上有很大的意义。     

Lithofacies features and mechanism of formation of “Zihe-type” time- and strata-bound iron ore deposits in central Shandong province

The Lower Palaeozoic system is a series of iron-bearing rocks consisting mainly of shallow sea-fades carbonates. On the basis of microfacies analysis of the carbonate rocks, the Lower Palaeozoic sedimentary sea basin is divided into two broad sedimentary-tectonic regions of four sedimentary facies and eight subfacies. The original iron-rich carbonates were deposited in saltlakes, lagoons, etc. of the restricted basins. Over the long geological history, the original iron formations were reconstructed to various extents by late tectonic processes. Geological observations and studies on the equilibrium mechanism of oxygen/sulfur isotopic fractionation and the composition and temperature of fluid inclusions in the minerals indicate that thermal brines played an important role in reworking of the original iron-rich carbonate rocks, which led to the formation of sedimentary-reworked strata-bound ore deposit.     

层状云对积云发展和降水的影响——一种云与云之间影响的数值模拟

利用我们已建立的二维积云降水模式,在相同的大气层结条件下,模拟了孤立积云和层状云中积云的发展和降水情况。结果表明,层状云的存在对积云的发展有显著的促进作用,降水量可加大到几到几十倍,从而认为积层混合云系可能是产生大雨和暴雨的一种重要机构,这与梅雨锋里锋区混合云系常产生暴雨的观测事实比较符合。     

一次梅雨暴雨过程的数值模拟

利用中尺度10层湿模式对一次梅雨暴雨过程作了数值模拟,较好地模拟了次天气或中间尺度系统的演变。由模拟结果分析表明: 1.形成暴雨的次天气或中间尺度系统的演变,雨带、暴雨中心位置和强度变化在低层涡度场上反映最清晰。与暴雨中心直接关联的是低层正涡度中心。这次过程中,两次正涡度中心的东移形成了前、后两次降水。 2.当低层正涡度中心移近或叠置在高层负涡度中心之下时,其强度增强,中层上升运动与暴雨也加强。它们是流场上高、低空急流之间动力耦合作用的结果。 3.雨区上空,边界层顶附近存在着一个主要表现为湿度逆增的湿暖盖——θ_(?e)高值中心。它与强风暴中的暖盖不同。此湿暖盖的形成和维持与西南急流输送暖湿气流有关。它的存在不仅有利于暴雨区水汽和能量的辐合,还有利于积云尺度对流的不断诱发,而且它的存在更构成了中层为不稳定,低层为稳定这一对流层的层结结构特点,从而使不稳定的对流降水叠加在稳定性降水之上,构成了梅雨锋大暴雨。     

岩体倾覆的多块体分析

倾覆是岩体失稳破坏的主要方式之一。岩体的倾覆可能呈单块体状,即岩体在其失稳的过程中仍保持其整体性;也可能呈多块体状,即岩体在其失稳的过程中分裂成多个块体,各块体之间产生差异运动,岩体发生解体。对倾角陡立的层状结构岩体及其有条块状结构的岩体,这种多块体倾覆较为常见。     

某些方解石单晶的光学质量评价

本文用光学方法检查了经野外地质工作者挑选过的天然方解石单晶的光学质量。发现部分晶体的光学均匀性很差,晶体中的光散射颗粒很多,不能满足作为光学介质的要求。