The geochronology and origin of mantle sources for late cenozoic intraplate volcanism in the frontal part of the Arabian plate in the Karacadağ neovolcanic area of Turkey. Part 1. The results of isotope-geochronological studies

This paper considers results from isotope-geochronological (K-Ar) studies of the products of Neogene-Quaternary volcanism in the Karacada? area, which is situated within the northern frontal part of the Arabian plate. It was found that magmatic activity has been evolving at this location for at least the last 11–10 Myr and was distinctly discrete in character. Three stages of volcanism have been identified: (I) Early or Miocene, ～11–6.7 Ma; (II) Middle or Pliocene-Early Quaternary, 4–1 Ma; and (III) Late or Late Quaternary, 0.4–0.1 Ma. The most recent manifestations of magmatic activity in the region date back to about 100000 years ago. An analysis of the spatial distribution of volcanic centers of different ages in the Karacada? neovolcanic area shows that the magmatism of that region involved a lateral migration of activity from northwest to southeast along a major regional tectonic fault. The migration was caused by the movement of local tension zones where the lithosphere was thinner and deep-seated mantle magmas were ascending.     

Revised determination of the paleointensity in the cretaceous from the collection of A.S. Bol’shakov and G.M. Solodovnikov

A large volume of data on the paleointensity H _an obtained by A.S. Bol’shakov and G.M. Solodovnikov is ignored in modern reconstructions because the authors did not indicate whether they used the check-point procedure for the detection of chemical alterations in rocks associated with determination of H _an. The paper presents new values of H _an determined by the Thellier-Coe method with the use of the checkpoint procedure from samples of the Armenian collection of Cretaceous rocks used in published studies of Bol’shakov and Solodovnikov. The new results are close to the published ones and point to a small value of the geomagnetic field in the Cretaceous, thereby corroborating Bol’shakov-Solodovnikov’s hypothesis on a low paleofield in the Mesozoic. Our study of samples of the collection studied confirms the reliability of Bol’shakov-Solodovnikov’s determinations of H _an.     

The surface geochemical exploration of oil and gas in the Gangbatong-Ya’anxiang and the Dongqiao-Nam Co of the Qinghai-Tibet region

Due to the complexity of geological background and the adverseness of natural geographical environment in the Qinghai-Tibet Plateau, it is very difficult to carry out petroleum geological study in this region. The Qinghai-Tibet Plateau is the only blank space of petroleum exploration on a large scale. The authors carried out the surface geochemical exploration of oil and gas in the Gangbatong-Ya’anxiang and Dongqiao-Nam Co of the Qinghai-Tibet region. Based on the data of actual detection and experiments in the studied area, the characteristics of concentration and profile distribution of the main geochemical exploration indicators (total adsorbed hydrocarbon, altered carbonate, thermal released mercury, etc.) were discussed. The origin of hydrocarbon was also discussed. Moreover, the oil and gas potential of different sections in the Qiangtang Basin and the Biru Basin were evaluated, which could provide references for the exploration and prediction of oil and gas in this region. The concentrations of total adsorbed hydrocarbons in the Ya’anxiang of Suoxian County-Zadong of Baqing County and the Jiecha-Dangxiong of Anduo County in the Qinghai-Tibet region are high, averaging 312.64 μL·kg^?1 and 164.36 μL·kg^?1. Their altered carbonate concentrations are relatively low, averaging 0.11% and 0.56%. Their concentrations of thermal released mercury are relatively high, averaging 13.09×10^?9 and 1.94×10^?9. Geochemical exploration results in fact reflect hydrocarbon information in the underground, which are mainly petroleum associated gas and over-matured cracking gas. The Jiecha-Charenluma and the Xiamaya’ertong-Suoba sections in the Qiangtang Basin are the most favorable ones for oil and gas and the Ekou-Zadong section is relatively favorable one, while the Nam Co and the Zigetangcuo-Dongqiao sections in the Biru Basin are the favorable ones for oil and gas, and the Jiang Co-Nading Co and the Ya’anxiang-Ya’ertong sections are relatively favorable ones.     

The depth of Moho in the mainland of China

ＴｈｅｄｅｐｔｈｏｆＭｏｈｏｉｎｔｈｅｍａｉｎｌａｎｄｏｆＣｈｉｎａＲｏｎｇ－ＳｈｅｎｇＺＥＮＧ；（曾融生）Ｗｅｉ－ＧｕｏＳＵＮ；（孙为国）Ｔｏｎｇ－ＥｎＭＡＯ（毛桐恩）ＺｈｏｎｇＹａｎｇＬＩＮ；（林中洋）Ｈｏｎｇ－ＸｉａｎｇＨＵ；（胡鸿翔）ａｎｄＧ...     

The Rigid body of Paleo－continent in the crust of Taiwan and the recent plate movement

ＴｈｅＲｉｇｉｄｂｏｄｙｏｆＰａｌｅｏ－ｃｏｎｔｉｎｅｎｔｉｎｔｈｅｃｒｕｓｔｏｆＴａｉｗａｎａｎｄｔｈｅｒｅｃｅｎｔｐｌａｔｅｍｏｖｅｍｅｎｔＧａｎｇ－ＸｉａＬＩＵ（刘光夏），Ｗｅｎ－ＪｕｎＺＨＡＯ（赵文俊）Ｗｅｎ－ＪｕＲＥＮ（任文菊）ａｎｄＸｉｕ...     

The heterogeneous characteristics of crust-mantle structures and the seismic activities in the northwest Beijing region

Introduction Zhangjiakou-Bohai seismic zone is a major active seismic zone that passes through the north-ern part of North China. Zhangjiakou-Beijing area, the northwest part of North China, is located at the intersection position of Yanshan, Taihangshan uplift, and Shanxi down-faulted zone, and the geological structures in this area are extremely complicated. Many researchers in the geoscience circle always pay close attention to this region because Yanqing-Huailai region is located in th…     

Professor Yu.D. Kalinin: The founder and first Editor-in-Chief of the Journal “Geomagnetism and Aeronomy” (Towards the Centenary of the Birth and to the 50th Anniversary of the Foundation of This Journal)

Information is given regarding the life, work, scientific research, and organizational activities of Professor Yu.D. Kalinin, the founder and the first editor-in-chief of the journal “Geomagnetism and Aeronomy.” The paper is devoted to the centenary of the birth of Yu.D. Kalinin and to the 50th anniversary of the beginning of the publication of the journal.     

Comment on the paper “The Relationship between Multifractal and Entropy Properties of Seismic Noise in Kamchatka and Irregularity of the Earth’s Rotation” by A.A. Lyubushin,G.N. Kopylova,and Yu.K. Serafimova

Izvestiya, Physics of the Solid Earth - Abstract—In my comment on the paper by A.A. Lyubushin, G.N. Kopylova, and Yu.K. Serafimova, I focus on the problem of legitimacy of seismological data...     

The Role of Gravity, Magnetic and Electric Prospecting Techniques in the Geological Survey of the Qiangtang Basin

The Qiangtang basin is one of the large-scale basins in China, which is located in the high-altitude and cold area. In 1994 the preliminary gravity, magnetic and electric prospecting work was undertaken in this area. Over three years the gravity, magnetic and electric reconnaissance work had been completed. The integrated interpretation of complex gravity, magnetic and electric data had identified the boundary of the basin. The relationship between the basin and mountains is a south-north ramp structure. The basin structure consisted of one uplift and two sags, five depressions and two arches. The complex evaluation showed that the regions of Baitanhu and Youyiquan in the Qiangtang basin were considered to be the most perspective ones in sense of oil-gas bearing.     

The Inauguration of the Fourth Board of Directors and the Fifth Academic Symposium of the Seismological Society of China jointed convened in Beijing

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The coupling instability of Rossby and topographic Rossby waves in the equatorial area

Before the 1980s, El Ni?o was believed as the sea surface warming along the coast of Peru in South America. As the positive anomaly strengths, the warm water expands westward along the equator to form large area of anomalous high sea surface temperature. Rasmusson and Carpenter (1982) summarized the de-velopment process of the sea surface warm water and the corresponding wind field[1] during ENSO cylce. However, this canonical El Ni?o was questioned by 1982-1983 warm episode and later dat…     

The velocity structure of crust and uppermantle in the Wudalianchi volcano area in—ferred from the receiver function

The Wudalianchi volcano is a modern volcano erupted since the Holocene.Its frequent occurrence of the small earthquake is considered to be indicator of active dormancy volcano.The S wave velocity structure is inferred from the receiver function for the crust and upper mantle of the Wudalianchi volcano area.The results show that the low velocity structure of Swave is widely distributed undemeath the volcano area and part of the low-velocity-zone located at shallow depth in the Wudalianchi volcano area.The low velocity structure is related to the seismicity.The Moho interface is not clear undemeath the volcano area,which may be regard to be an nec-essary condition for the lava upwelling.Therefore,we infer that the Wudalianchi volcano has the deep structural condition for the volcano activity and may be alive again.     

The CO2 Discharge in the Boundary Fault Areas of the Sichuan-Yunnan Block and Its Sources

A large number of CO2 springs outcrop along the boundary faults of the Sichuan-Yunnan block and in their neighboring areas.These springs are of a roughly similar distribution as the epicenters of strong earthquakes since 1900.This similarity indicates that the CO2 discharges could be directly related to the modern seismic activity in that area.The evidences of stable carbon and oxygen isotopes indicate that an overwhelming majority of the CO2 released from modern active faults is derived from the deep earth crust.There are 2 main mechanisms of CO2 discharge.Modern active faults are able both to produce directly a lot of CO2 due to thermodynamic metamorphism and to provide passages for the CO2 constituent coming from the lower crust or upper mantle.By continuously monitoring the dynamic changes of CO2 discharges,it would be possible to obtain the information of earthquake precursors that reflect the physical and chemical changes of the earthquake sources.     

An assessment of the potential use of the nematode to copepod ratio in the monitoring of metals pollution. The Chañaral case

We discuss the use of the nematode to copepod ratio in relation to determining the extent of metals impact using the Cha?aral area of northern Chile, where the dumping of copper mine tailings has taken place for many years, as an example. Data were collected from 12 beaches in the area on eight occasions between January 1997 and October 1998. We find that the ratio is not a good predictor of pollution due to the generally low densities of meiofauna on impacted beaches and the absence of harpacticoid copepods from those beaches. We suggest that in the case of metal pollution the mean number of Harpacticoida per site may be a better indicator of impact stress. We rule out the use of the nematode to copepod ratio as an indicator in biomonitoring studies where metal enrichment is thought to occur.     

Reply to the Comment by V.A. Saltykov on the Paper “The Relationship between Multifractal and Entropy Properties of Seismic Noise in Kamchatka and Irregularity of the Earth’s Rotation” by A.A. Lyubushin,G.N. Kopylova,and Yu.K. Serafimova

Izvestiya, Physics of the Solid Earth -     

The correlation between the characteristics of seismic wave propagation in Western Caucasus and the geological–tectonic features of the region

The relationship between the characteristics of seismic waves in the Western Caucasus and the geological-tectonic structure of the region is studied for identifying the specificity of seismic propagation in the mountainous regions with a complicated geological structure and forecasting the characteristics of the propagation from the geological and tectonic data. The interpretation is presented for the estimates of the Q-factor of the medium (Q(f) ~ 55f^0.9 in the region of Sochi and Q(f) ~ 90f^0.7 in the region of Anapa), seismic wave enhancement in the upper crustal layers (A(f) ~ 1), and peak ground acceleration residuals, which were previously determined from the records of the local earthquakes and show the distributions of local variations in the parameters of seismic wave radiation and propagation. The obtained characteristics are interpreted in the context of the up-to-date information about the tectonic, geological, and deep structure of the epicentral zones in the Western Caucasus and neighboring territory of the Black Sea. The discrepancies revealed in the low-frequency behavior of the Q-factor in the vicinities of Sochi and Anapa is accounted for by the spatial scale and character of tectonic dislocations of the rocks in these regions. The local variations in the parameters of seismic radiation and propagation are probably related to the geological features of the region such as the fault structures, including the thrusts, shatter zones, oblique seismic boundaries, variations in the thickness and consolidation of the sedimentary cover, as well as the peculiarities in the structure and material composition of the basement.     

The Results and Comparison of "Logical-Tree" Seismic Zoning in the Panxi Area

On the basis of the technological route of seismic hazard analysis,the methods for determining seismicity parameters,such as b value,annual occurrence rate,and the seismic spatial distribution function,are discussed.Then,the seismic intensity zoning in Panxi area in Southwest China is carried out by applying the "logical-tree,"which is made up of multi-parameter schemes.It is clearly shown from the results that seismic intensity zoning is influenced by many uncertain factors and it is necessary to seek a certain balance between seismic safety and investment interest and a good way,with the present limited knowledge level,to obtain seismic intensity zoning is through the "logical-tree" method.     

The Character of Shear-wave Splitting in Marble in the Critical State of Rupture

This paper mainly observed and analyzed the character of shear-wave splitting in rock specimens while they were in the critical state of rupture. The rock specimens for study are made of Laizhou marble from Shandong, China. A series of records were obtained from two rock specimens when they were in the critical state of rupture. The result shows that, in the critical state just before rock rupture, there may be the phenomenon of rise and fall in the time delay of shear-wave splitting, even though the load was kept constant. That is to say, the time delay of shear-wave splitting may have a falling process before rock rupture.     

The record of paleoclimatic change from stalagmites and the determination of termination Ⅱ in the south of Guizhou Province,China

A high-resolution climate record from 163.00 kaBP to 113.80 kaBP has been obtained through TIMS-U series dating and carbon and oxygen isotope analysis of the three large stalagmites from two caves in the south of Guizhou Province, China. The record of the oxygen isotopes from the stalagmites reveals that the undulation characteristics between the cooling event of the glacial period and the warming event of the interglacial period in the research area can compare well to those of ice cores, lake sediments, loess and deep sea sediments on the scale of ten-thousand years or millennium time scale. The climate undulation provided by the record of the stalagmites has a coherence with the global changes and a tele-connection to the paleoclimate changes in the north polar region. Our results suggest that the direct dynamics of paleo-monsoon circulation changes reflected in the record of the stalagmites might be caused by changes of the global ice volume, and in turn related to various factors, including the sol