Terrane Processes at the Pacific-margin of Gondwana （TAPMOG）

Although the terrane concept emerged from the study of northern hemisphere active continental margins and orogenic belts, it is largely in the Southern Hemisphere, in particular in relation to the Gondwana supercontinent, where it has seen its fullest flowering. New data continue to emerge, and new models and techniques are being actively developed. For these reasons, “Terrane Processes at the Pacific-margin of Gondwana”     

Assessment of cadmium contamination in the sediments of Changjiang （Yangtze） River by reflectance spectroscopy

The Takab area in NW of Iran is an important gold mineralized region with a long history of gold mining. In this study ASTER data is used to evaluate environmental effects of gold mining. The results show that mining activities have resulted in release of potentially toxic metals （PTMs） in the area. Principal component analysis （PCA） of ASTER data is used to map sources of PTMs and their secondary hosts （iron oxides） through alteration mapping. The results show that selective PCA is a robust yet time consuming technique for alteration mapping. A color composite is created for finding common hydrothermally altered rocks. The created color composite successfully mapped the known deposits and anomalous areas identified by geological survey of Iran. Because of the low spatial resolution of ASTER sensor, the iron oxide mapping is restricted to the wider portions of the streams. Spectral analyses confirm the presence of hematite and goethite in stream sediments. This is in accordance with measured pH values.     

Arsenic pollution of groundwater and its release mechanism in the central part of the Hetao Plain, Inner Mongolia, China

Arsenic pollution of groundwater has become a serious health problem in several regions of the world. Wuyuan County located in the central part of the Hetao Plain, Inner Mongolia, is one of the most severely arsenic polluted areas. Peoples of the county have used groundwater of shallow （12-25 m） tube-well as drinking water. The groundwater is Na-HCO3 and Na-Cl type on the piper plots and aligns with steady Ca ： Mg ratio on cation diagram. The arsenic content in the water is more than 0.2 mg/L and the highest value reaches up to 0.52 mg/L. Drilling data show that Holocene sediments are divided into three zones on the basis of their color appearances; brown, grey and dark gray zones. The strata from 2m to 9-14m under the surface are mainly composed of clay and silt which are impermeable layers. The grey and dark grey zones composed of sand underlie the impermeable bed and the condition of their zones is reductive. At the depth of 30 m near the bottom of drilling, ORP of the groundwater is -300- -400 mV. The dark grey sand changes to yellow in color under the atmosphere. Under reducing environment, the color returns to its original dark grey. The characteristic color is due to amorphous or low-crystalline Fe sulfide coating sand grains. The sediments are of fluvial origin by the Yellow River. The arsenic content in the sediments is rich in fine-grained part and its values are more than 20 mg/kg in clay layer. The highest is 38 mg/kg. X-ray diffraction and macroscopic observation show that the clay layer is made of minerals such as chlorite and illite and contains high quantities of organic matter.     

Basal Melt-out Structure in the Luoauan Formation and Its Significance

The Late Precambrian Luoquan Formation occurring on the southern margin of the North China platform is of important significance for the study of the tectonics, palaeogeography, palaeoclimatology and regional stratigraphy of the North China and Yangtze platforms. The origin of diamictites of the formation has long been a subject of controversy. Recently a certain type of cross bedding structure has been recognized in the massive diamictite. Analysis of the process of deposition indicates that the structure was formed by the basal melt-out process of the glacier and, to some extent, its form is the manifestation of the primary structure of basal debris-rich glacial ice. The discovery of this sedimentary structure is inducive to the understanding and reconstruction of the features and environmental conditions for the development of the glaciers in the Luoquan Glacial Epoch.     

Spatiotemporal distribution of snow cover and its variation in the upper reaches of the Taolai River basin，Qilian Mountains北大核心CSCD

Snow is an important part of the cryosphere and plays an important role in the hydrological cycle and energy balance. Study of the spatiotemporal characteristics of snow cover and its change is the prerequisite for analyzing the formation,distribution and variation of runoff from mountains in inland river basins. In this study,we selected the upper reaches of the Taolai River basin of Qilian Mountains as the study area,used down⁃ scaling methods to obtain high-resolution snow depth data,and adopted methods of spatial statistics,sensitivity analysis and contribution separations to quantify snow cover distribution and variation influenced by terrain and the regional climate during the time period from 2002 to 2018. Results showed that basin early average snow depth ranged from 0 cm to 2. 5 cm,with variation from -0. 19 cm·a-1 to 0. 06 cm·a-1. The area of snow depth re⁃ duction during the study period accounted for 68. 30% of the total area. It was found that the snow depth increase more with altitude and less with the increase of slope. Variation of snow depth increased below 2 500 m a. s. l. and decreased above 2 500 m a. s. l. As the slope increases,it first increases and then decreases;the snow depth of each aspect decreases,especially in the northwest orientation. The sensitivity of snow depth to air tempera⁃ ture and solar radiation were found negative in general,while that of the precipitation was found positive. The precipitation in high-altitude areas has a relatively large contribution to the snow depth variation,while in the val⁃ ley areas,the contribution of temperature to snow cover is more significant. This work provides an example for the study of snow dynamics in the upper reaches of inland river watersheds,and benefits model simulation and prediction of mountain runoff and regional water management. © 2023 The Author(s).     

Seismic Technique for Studying Sedimentary Layer: Bohai Basin as an Example

The upper tertiary to quaternary is the main target layer for oil and gas exploitation in Mainland China, especially crude oil production in the Bohai Basin accounts for approximately 40% of China’s crude oil production. Therefore, a study of the Upper Tertiary to Quaternary has important significance for science and practical applications. In this study, using the receiver function method, Ps and later phase extraction, the sedimentary thickness and an accurate estimate of velocity ratio can be obtained. The technique is simple, its calculation results are unique, and it can be applied to a study of the sedimentary layer. The technique is promising for oil and gas exploration.     

Petrological Study on the Ductile Shear Zones in the Core of the Eastern Qinling Orogenic Belt in Western Henan

A series of ductile shear zones of the overthrust and strike-slip-types and related ductile shear metamorphicrocks, including tectonic melange and mylonites. were formed in the core of the Qinling orogenic belt in thecourse of the Caledonian-Indosinian ductilc and brittle-ductile reworking. The study on their petrography. va-riations in composition and conditions of formation is conducive to revealing the metamorphism-deformationhistory of the core of the Qinling orogenic belt and further to understanding the dynamic mechanism of its evo-lution.     

Evolution of Chinese Neogene Rhinocerotidae and Its Response to Climatic Variations

Chinese Neogene Rhinocerotidae has quite a complete record and its temporal range is the Early Miocene to Late Pliocene. The samples include 25 species in 4 tribes of 2 subfamilies. They are used as a foundation for the study of the evolution of the family and its relation to climatic changes. Taxonomic diversity, new records and extinctions are estimated for each Chinese Neogene mammal faunal unit (NMU). The diversity of Chinese Rhinocerotidae varies noticeably throughout the Neogene and is recognized within five stages: the Middle Miocene and Late Miocene are stages of high diversity and the Early Miocene, early Late Miocene and Pliocene are stages of low diversity. Rhinocerotid diversity and morphology are closely related to environmental factors and particularly sensitive to changes in ambient temperature and humidity. The interpretation of climatic variation reflected in the evolution of Rhinocerotidae corresponds precisely with the conclusions drawn from other workers and provides new evidence fen     

Study on the Safety of the Foundation Rock Masses in the Tangkou Bank of the Taipinghu Bridge

The Taipinghu Bridge is an important project, and the safety of rock masses of its foundation is very crucial. This article analyzes the potential causes of the deformation of the rock masses of the bridge foundation, and uses the Fast Lagrangian Analysis of Continua to analyze the geologic model. The simulating process shows that no mater in the excavating process or in the loading process the rock masses are suit for the engineering. The modeling and analyzing process can be used for reference.     

Palaeoseismic Events in Karst Terrains along the Northern Bulgarian Black Sea Coast

The study of the palaoseismic events in the karst terrains of the Bulgarian Black Sea coast is a very important up-to-date problem. The investigated region is one of the highest-energy regions in Bulgaria with established and recorded catastrophic historic and contemporary earthquakes. The terrain is subjected to the influence not only of its own earthquake foci but also of those in Romania and Russia. The palaeoearthquakes that caused considerable disturbances in the karst terrains along the Northern Bulgarian Black Sea coast have left significant traces. They caused disturbances in the environment and the relief (rearrangement of the surface and ground water karst basins, partially or entirely collapsed caves, deformed caves, oil, gas and salt intrusions and gravitationally formed caves). The ecological consequences in historic and contemporary aspects were catastrophic. The palaeoseismic dislocations were formed as a result of global, regional and local geodynamic events related with the destruction     

Unity of the national and the international in the socio-cultural development of the peoples of the USSR

International unity is becoming ever stronger in this country owing to an increasing similarity in the development of the cultural environment. This comprises the provision of all the country's republics with a sufficient number of schools, theatres, and other institutions and cultural information media in accordance with the needs of the population. An important part is played by the rise in ‘the general educational level, as well as the level of professional qualifications and skills. Among all the Soviet nations and nationalities, this rise being more rapid among formerly backward peoples. Prominent among the factors of internationalization is the progressive development of the nationalities’ cultural resources, while professional culture is being increasingly brought within the reach of the masses.The implementation of the nationalities policy promotes the all-round development of all Soviet nations and nationalities, their drawing together, the upsurge of the individual capabilities of every Soviet citizen.     

Global repeating events in the history of the Earth and the motion of the Sun in the Galaxy

Chronological analyses of correlations between certain global repeating events (mass extinctions of marine organisms, meteorite impacts, and flashes in the frequency of geomagnetic reversals) during the Phanerozoic Eon and the motion of the solar system in the Galaxy are presented for five rotationally symmetrical models for the regular Galactic gravitational field. Thirteen of sixteen mass-extinction events can be described by a repetition interval of 183±3 million years. This is in agreement with the anomalistic period (interval between two subsequent passages of the Sun through the apocenter of its Galactic orbit) in the model of Allen and Martos. The positions of the minima and maxima in Gaussian functions approximating the frequency distribution for geomagnetic reversals also agree with the times of passage of the Sun through the apocenter and pericenter, respectively, of its Galactic orbit in this model. The maximum in the distribution of the deviations of the dates of mass extinctions from the nearest dates of impacts of large, crater-forming bodies is close to zero, providing evidence that many such events are correlated. As a rule, extinctions follow impact events. The impacts of large bodies have occurred most often when the solar system passes through the Galactic plane, while mass extinctions occur more often at some distance from the Galactic plane (about 40 pc). As a rule, intervals of increases in the frequency of geomagnetic reversals coincide with dates of impacts of large bodies. At the same time, these intervals do not show a clear correlation with the dates of mass extinctions. The intensity of mass extinctions, like the energy released by impacts, is consistently higher in periods when the Sun is moving from the apocenter toward the pericenter of its orbit, than when it is moving from the pericenter toward the apocenter. Thus, there is evidence for a variety of relationships between repeating global events in the Phanerozoic and the motion of the Sun in the Galaxy. Long-period variations in the frequency of geomagnetic reversals are correlated with the orbital motion of the Sun, and increases in the frequency of geomagnetic reversals are correlated with impacts. Mass extinctions are correlated with the impacts of large bodies, whose motions may have been perturbed by clouds of interstellar material concentrated toward the Galactic plane and by the shock front associated with the Perseus spiral arm, through which the solar system passes. The velocity of the Sun relative to the spiral pattern is estimated.     

Deviation of the major axis of the inertia ellipsoid of the Moon from the direction toward the Earth

It is known from observations that the center of mass of the Moon does not coincide with the geometric center of its figure, and the line connecting these two centers is not aligned with the direction toward the center of the Earth, instead deviating toward the Southeast. This stationary deviation of the axis of the inertia ellipsoid of the Moon to the South of the direction toward the Earth is analyzed. A system of five linear differential equations describing the physical libration of the Moon in latitude is considered, and these equations are derived using a new vector method taking into account perturbations from the Earth and partly from the Sun. The characteristic equation of this system is obtained, and all five oscillation frequencies are found. Special attention is paid to the fifth (zero) frequency, for which the solution of the latitude libration equations are stationary and represents a previously unknown additional motion of the rotational axis of theMoon in a cone with a small opening angle. In contrast to the astronomical precession of the Earth, the rotation of the angular-velocity vector is in the positive direction (counter-clockwise), with the period T ₃ = 27.32 days. On this basis, this phenomenon has been named “quasi-precession.” This quasi-precession leads to a stationary inclination of the major axis of the inertia ellipsoid of theMoon to the South (for an observer on Earth), making it possible to explain one component of the observed deviation of the center of mass of the Moon from the direction toward the Earth. The opening angle of the quasiprecession cone is approximately 0.834″.     

从榴辉岩与围岩的关系论苏鲁榴辉岩的形成与折返

位于华北和扬子两板块碰撞带中的苏鲁榴辉岩形成的温压条件不但是超高压，而且是高温。榴辉岩的PTt轨迹表明其为陆-陆磁撞俯冲带的产物。榴辉岩的区域性围岩花岗质片麻岩为新元古代同碰撞期花岗岩，榴辉岩及其他直接围岩皆呈包体存在于其中，并见新元古代花岗岩呈脉状侵入榴辉岩包体中。区域性围岩新元古代花岗岩的锆石中发现有柯石英、绿辉石等包裹体，表明新元古代花岗岩的组成物质也经受过超高压变质作用，且榴辉岩与围岩新元古代花岗岩的锆石U-Pb体系同位素年龄基本相同。但新元古代花岗岩所记录的变质作用和变形作用期次（或阶段）却少于榴辉岩。椐上述可得如下推断：超高压榴辉岩与新元古代花岗岩岩浆是同时在碰撞带底部（俯冲板块前部）形成的；榴辉岩的第一折返阶段是由新元古代花岗岩岩浆携带上升的，其第二折返阶段是和新元古代花岗岩一起由逆冲及区域性隆起而上升，遭受剥蚀。     

某高速公路下伏煤矿采空区稳定性分析

在论述某高速公路下伏砦脖煤矿采空区地质、采矿和工程地质特征的基础上, 进行了稳定性数值模拟分析, 定性与定量地分析与评价了该煤矿采空区的地表变形特征及稳定性。研究结果表明: 该煤矿采空区的变形尚未完成, 对拟建的高速公路将产生很大的危害, 必须采取相应的工程治理措施。      

摩擦桩基桩土间极限摩阻力取值问题探讨

通过对广珠东线高速公路横沥大桥的试桩及土体的工程地质条件分析,总结出影响摩擦桩基桩土间极限摩阻力取值的一般问题以及解决问题的方法和措施。     

The Importance of the Precipitation and the Susceptibility of the Slopes for the Triggering of Landslides Along the Roads

In order to characterise the influence of the heavyrains on the observed landslides during the 1996–1997hydrological cycle, rainfall records for the last 100years are analysed from 104 stations in easternAndalusia. Regarding the amounts of rain recordedbetween October 1996 and March 1997 in the 104stations studied, 31 presented new all-time records;15 presented values that were 80–100% of thepre-1995 record; 49 stations, 80–50%; and 9stations, < 50%. A map has been devised of thesusceptibility of the materials through which thesouth-eastern Andalusian road network crosses,together with an inventory of the damage caused byinstability phenomena on banks and cuttings of theroad network during the winter of 1996–1997. Therelationships between the rainfall during the studyperiod, the damage caused to the road network and thesusceptibility of the materials affected are analysed.The results indicate that there is a clearcorrespondence between the rainfall recorded and thesusceptibility of the materials with the inventorieddamage. It is concluded that the widespread seriousdamage caused in early 1997 to the roads andsurrounding areas in the Alpujarra region and thecoast of the Province of Granada was mainly caused bythe extraordinarily heavy rains. However, considerablyless damage was observed where the susceptibility ofthe terrain is low, thus highlighting the extremeusefulness of terrain-susceptibility maps for riskprevention and territorial planning.     

Paleomagnetic implications on the evolution of the tethys belt from the atlantic ocean to the pamirs since the triassic

We first re-examined the apparent polar wander curves for stable Eurasia and Africa since the Triassic. These curves were then combined together with curves of North and South America according to the kinematics of the Atlantic ocean and a synthetic polar wander curve was given. Then, most of the paleomagnetic results from the Tethys mobile belt, from the Atlantic to the Pamirs, were analysed.Several groups of plates, microplates and blocks can be seen. First, relatively stable regions like Maghreb and Sicily, which have not moved much. Then we have a group formed by Iberia, Sardinia, Italy and, to a lesser extent, Corsica and the Western and Central Alps. For these blocks, movements are anticlockwise rotations chiefly driven by the anticlockwise rotation of Africa, but they are sometimes stronger.To the east, a major change takes place. The north of the Aegean Sea and the Ionian zone are clockwise rotated and these rotations are recent: Oligocene-Miocene for the first part, Pliocene to the present for the second part.A major problem arises in Turkey, Caucasus and Iran. Paleomagnetic results indicate a position far to the south of Eurasia, and, at the same time, geological evidence is in favour of a position close to Eurasia. We discuss these discrepancies.