A note on some early radiosonde temperature observations in the Antarctic lower stratosphere

The behaviour of the Southern Hemisphere stratosphere has attracted considerable interest, and been compared with the Northern Hemisphere, since the International Geophysical Year (1957–58) when the sudden (explosive or accelerated) springtime warming phenomenon in the Antarctic was first observed. Over the years studies of upper air temperature and wind observations have been made, principally through the spring months when the polar vortex breakdown occurs, utilising both ground-based (rawinsonde, rocket) and more recently, satellite-derived data. Although the radiosonde-derived temperature data are limited both by the number of reporting stations, and the practical difficulty of securing observations much above the 100 hPa level, useful records exist from 1956 or 1957. These have shown that in the 1959 southern spring, the lower stratosphere was relatively colder, and the warming rate through the season was essentially more regular, with little evidence of the marked but short-lived temperature fluctuations usually found. Similar, but not quite such wide-spread conditions occurred again in the 1961 spring. In another study, 30 hPa temperature fields over the Antarctic continent, which could be drawn for the 1967 spring, showed the complexity of the polar vortex breakdown. These features are recalled because extension of the 100 hPa springtime temperature series for the Australian Antarctic station at Casey (66.3°S, 110.5°E) shows that in 1985 and part of 1986, the temperature behaviour there was similar to, but not quite so extreme as that which occurred at Mirny (66.5°S, 93.0°E) in 1959.     

江西中西部黄龙组底部的Pseudostaffella层位问题

近年来，在江西中西部黄龙组底部发现了Ｐｓｅｕｄｏｓｔａｆｆｅｌｌａ，由此涉及到了黄龙组底部的地层时代及对比问题。根据匕高石坎尾剖面上类化石的分布和动物群性质，江西黄龙组底部与Ｅｏｓｔａｆｆｅｌｌａ、Ｓｃｈｕｂｅｒｔｅｌｌａ共生的Ｐｓｅｕｄｏｓｔａｆｆｅｌｌａ和贵州、湖南Ｐｓｅｕｄｏｓｔａｆｆｅｌｌａ带组合面貌相差甚远。江西中西部至今不存在确切的Ｐｓｅｕｄｏｓｔａｆｆｅｌｌａ带。     

Tectonic evolution of lower crustal rocks in an exposed magmatic arc section in the Hidaka metamorphic belt, Hokkaido, northern Japan

Abstract : The Hidaka metamorphic belt consists of an island-arc assembly of lower to upper crustal rocks formed during early to middle Paleogene time and exhumed during middle Paleogene to Miocene time. The tectonic evolution of the belt is divided into four stages, D₀rs, D₁, D₂rs, and D₃, based on their characteristic deformation, metamorphism, and igneous activity. The premetamorphic and igneous stage (D₀) involves tectonic thickening of an uppermost Cretaceous and earliest Tertiary accretionary complex, including oceanic materials in the lower part of the complex. D₁ is the stage of prograde metamorphism with increasing temperatures at a constant pressure during an early phase, and with a slight decrease of pressure at the peak metamorphic phase, accompanying flattening of metamorphic rocks and intrusions of mafic to intermediate igneous rocks. At the peak, incipient partial melting of pelitic and psammitic gneisses took place in the amphibolite–granulite facies transition zone, the melt and residuals cutting the foliations formed by flattening. In the deep crust, large amounts of S-type tonalite magma formed by crustal anatexis, intruded into the granulite facies gneiss zone and also into the upper levels of the metamorphic sequence during the subsequent stage. During D₁ stage, mafic and intermediate magmas supplied and transported heat to form the arc-type crust and at the same time, the magmatic underplating caused extensional doming of the crust, giving rise to flattening and vertical uplifting of the crustal rocks. D₂ stage is characterized by subhorizontal top-to-the-south displacement and thrusting of lower to upper crustal rocks, forming a basal detachment surface (décollement) and duplex structures associated with intrusions of S-type tonalite. Deformation structures and textures of high-temperature mylonites formed along the décollement, as well as the duplex structures, show that the D₂ stage movement occurred under a N-S trending compressional tectonic regime. The depth of intra-crustal décollement in the Hidaka belt was defined by the effect of multiplication of two factors, the fraction of partial melt which increases downward, and the fluid flux which decreases downward. The crustal décollement, however, might have extended to the crust-mantle boundary and/or to the lithosphere and asthenosphere boundary. The subhorizontal movement was transitional to a dextral-reverse-slip (dextral transpression) movement accompanied by low-temperature mylonitization with retrograde metamorphism, the stage defined as D₃. The crustal rocks from the basal décollement to the upper were tilted eastward on the N–S axis and exhumed during the D₃ stage. During D₂ and D₃ stages, the intrusion of crustal acidic magmas enhanced the crustal deformation and exhumation in the compressional and subsequent transpressional tectonic regime.     

Calculated and observed seismic behaviour of exposed upper mantle

In order to determine the seismic properties of rocks representing the continental crust/upper mantle transition, a structural and petrographical study of peridotites of the Ivrea-Verbano zone (N. Italy) has been undertaken. The seismic behaviour (Vp, Vs, birefringence, orientation of the fast shear-wave polarisation plane) has been calculated from the modal composition of rock samples, together with the crystallographic preferred orientation and the single crystal elastic constants, using the methods of Mainprice (1990). It is shown that the intrinsic anisotropy of peridotites is mainly due to the lattice preferred orientation (LPO) of olivine and to the competing effects due to the LPO of orthopyroxene. If present, well-oriented hydrous phases such as phlogopite, leads to both P- and S-waves velocities becoming drastically reduced, but the anisotropy and the S-wave splitting (mainly on the foliation plane) is increased. An attempt has been made to apply this petrologic and microstructural approach to understand the seismic properties of ultramafic rocks with the aid of a mobile seismic network set up in the Ivrea-Verbano zone. Five recording units with 3-component geophones were installed on the most representative lithologies of the Ivrea-Verbano zone: kinzigites, gabbros, stronalites, and on metapelites of the adjacent outcrop of the Serie dei Laghi. During five months the seismic network recorded 49 events that were mainly regional earthquakes. The preliminary analysis of the first arrival revealed a high-velocity anomaly near the Finero ultramafic massif. Rough calculations indicated that this anomaly could be due to a shallow-depth, peridotitic body about six kilometres thick. S-wave polarisation analysis was carried out on the horizontal components of the seismograms of four regional earthquakes that showed a first arrival propagating almost vertically at the recording sites. Four earthquakes were chosen in order to reconstruct the orientation of the polarisation plane of the shear phases. The preliminary results of this analysis have shown a qualitatively good agreement between the orientation of the polarisation plane of the fast shear-wave and the strike of the foliation at the station near Finero, located on kinzigites of the Ivrea-Verbano zone, although the relationships between the local structural setting and the polarisation orientations at the other recording sites is not yet so clear.     

宝顶石刻区污染地下水对造像岩体的破坏作用

污染地下水渗入大佛湾摩岩造像群，在石刻表面积聚可溶盐，加剧了石刻的侵蚀破坏，其中尤以泥质细粒长石砂岩风化剥落最为严重。研究渗水病害对石刻保护有重要意义。     

单纯克山病病区与单纯大骨节病病区生态化学环境的对比研究

本文对云南省牟定县申平村单纯克山病病区和陕北榆林县蟒坑村单纯大骨节病病区的生态化学环境进行了对比研究，表明两地生态化学环境仍处于低Ｓｅ水平。申平村人群仍有潜在型克山病病例，蟒坑村人群的骨质病变则出现很高的Ｘ线阳性检出率，说明两地的致病因子仍然活跃，从生态系物质含Ｓｅ量看出，蟒坑村的缺Ｓｅ程度较申平村高。此外，单纯克山病病区申平村土壤，粮食，人发中的Ａｓ明显高于蟒坑村和非病区。为此，从Ａｓ与Ｓｅ具有     

长江中下游地震同青藏高原北部地震的相关性

本文对比了1910—1987年发生的长江中下游地震和青藏高原北部地震,发现两者有比较好的对应关系。一般是,青藏高原北部先发生M≥6级地震,而后长江中下游地区发生M≥19/4级地震。对1910年以来的21次地震进行了统计分析,得到复相关系数R=0.74,能够在很高的显著性水平上通过F检验。地震活动在时间、空间、强度上的相关,现代构造运动及应力场等事实表明,长江中下游地震活动可能主要受青藏高原向东的横向推移运动的影响。     

黔南桂北下三叠统碳酸盐海岸—陆架沉积总体的沉积构成及沉积过程分析

在黔南桂北下三叠统进行沉积过程和沉积构成分析的基础上,识别出了构成碳酸盐海岸—陆架沉积总体的4种成因单位和7种沉积相。同时本文还对碳酸盐海岸—陆架沉积总体的演化过程及其与其它沉积总体的空间组合关系进行了讨论。