Seismic Hazard Assessment at Esfaraen‒Bojnurd Railway,North‒East of Iran

The objective of this study is to evaluate the seismic hazard at the Esfarayen-Bojnurd railway using the probabilistic seismic hazard assessment (PSHA) method. This method was carried out based on a recent data set to take into account the historic seismicity and updated instrumental seismicity. A homogenous earthquake catalogue was compiled and a proposed seismic sources model was presented. Attenuation equations that recently recommended by experts and developed based upon earthquake data obtained from tectonic environments similar to those in and around the studied area were weighted and used for assessment of seismic hazard in the frame of logic tree approach. Considering a grid of 1.2 × 1.2 km covering the study area, ground acceleration for every node was calculated. Hazard maps at bedrock conditions were produced for peak ground acceleration, in addition to return periods of 74, 475 and 2475 years.     

Structural Evolution and Halokinesis of Khaje Salt Diapir,North‒West of Iran

Geotectonics - The northeastern part of the Tabriz, Khaje area has been studied to determine the relationship between the orientation of local structures and regional tectonics, and the influence...     

Environment and Age of the Upper Devonian‒Carboniferous Zhulumute and Hongguleleng Formations, Junggar Basin, NW China: Ichnological and Palynological Aspects

Two Upper Devonian to Lower Carboniferous sections, namely the Bulongguoer and Haer(Gennaren area) in the Junggar Basin, Central Asian Orogenic Belt, in northwestern China were examined with regard to ichnology and palynology. The deposits of the Hongguleleng Formation and Namu Member of the Heishantou Formation, respectively, are mostly unbioturbated or poorly bioturbated, with poorly diversified trace fossils, which indicate unfavourable conditions for the burrowing benthic community during the Late Devonian and Early Carboniferous. The main factor governing the growth of the bioturbating population was the rapid sedimentation of fine-grained, volcanic material documented as tempestites, which buried the benthic fauna. In the Bulongguoer section, the presence of miospores Teichertospora torquata and Grandispora gracilis enabled identification of the broad Teichertospora torquata–Grandispora gracilis Miospore Zone from the transitional Frasnian/Famennian interval. More accurate identification of palynostratigraphical levels(DE and CZ Miospore zones) is only tentative. On the basis of palynofacies analysis, samples from the lower Bulongguoer section indicate deposition in more proximal conditions, whereas samples from the top of the section indicate deposition in a more distal environment. In the Haer section, only a general biostratigraphic indication for the Tournaisian was possible, owing to poor preservation of organic matter.     

Tectonic‒Thermal Coupling Metallogenic Models of Tethys Himalaya Pb‒Zn‒Sb‒Au Belt in Post-Collisional Stage

Geotectonics - Crustal-scale extensions occurred in the Tibetan Plateau during the post-collision stage, and leucogranites, N–S and E–W faults and other tectonic-thermal events were...     

Fluid-Rock Interaction of Shear Zones in Continental Crust:as Evidenced by Xincheng-Xishui and Hetai Shear Zones

There is a coupling of thermal, mechanical, chemical and fluidal processes in a continental shear zone. Both Xincheng-Xishui and Hetai shear zones are typical continental crust shear zones of greenschist facies environment. The representative mylonite zones of the shear zones are studied with whole rock major and trace element analyses. The chemical compositional variation tendencies in both shear zones are very similar and the gain-loss ratios of various components in the mylonitic rocks are reflected in the mass balance equations. The enrichment of those immobile high-field-strengh elements is considered to he related to the volume loss of the myionitic rocks in a shear zone. Based on the volume loss expression C_s/C_o=1/(1-V),the fractional volume losses (V)are 37.5％ and 36.5％-42.3％ respectively for mylonites and ultramylonites in the Xincheng-Xishui shear zone and 11％ and 28％ respectively for mylonites and phyllonites in the Hetai shear zone. The high volume loss and large removal of SiO_2 from     

Isotopic age and heterogeneous sources of gabbro‒anorthosites from the Patchemvarek massif,Kola Peninsula

New U?Pb (SHRIMP II) data on the age (2661.8 ± 7.1 Ma) and isotopic (Sm?Nd) composition of the Patchemvarek gabbro?anorthosite massif located in the junction zone between the Neoarchean Kolmozero-Voron’ya greenstone belt and Keivy paragneiss structure are discussed. The established age and geological?tectonic position of gabbro?anorthosites allow the prognostic metallogenic estimate of Ti?V?Fe mineralization to be extended to the entire Kolmozero-Voron’ya?Keivy infrastructural zone of the Kola?Norwegian province of the Fennoscandian shield.     

Genesis of Emerald Occurrences and Their Exploration Implications within Singhbhum Shear Zones, Eastern Indian Craton

Please refer to the attachment(s) for more details.     

Shear strength and compressibility of oyster shell–sand mixtures

This paper investigates the fundamental characteristics of shear strength and deformation of crushed oyster shell–sand mixtures to stimulate recycling of waste oyster shells. Standard penetration tests (SPT) and large-scale direct-shear tests were carried out with different kinds of dry unit weight and mixing rate of oyster shell–sand mixture. Correlations between N-value, dry unit weight, and friction angle of mixtures were observed from the results of experimental tests, making it possible to estimate the in situ strength from SPT, and the coefficient of volume compressibility from the confined direct-shear compression test. These results also make it possible to compute the settlement of oyster shell–sand mixture when used in soft ground improvement.     

Structure and Evolution of the Belomorian–Severodvinsk Shear Zone in the Late Proterozoic and Phanerozoic,East European Platform

Geotectonics - The tectonics, morphological features, and development stages of the Belomorian‒Severodvinsk shear zone (northwestern part) found in the East European Platform are considered....     

珠江口盆地成盆‒成烃‒成藏:代序

珠江口盆地位于太平洋俯冲的东部动力系统、印度?澳大利亚板块与欧亚碰撞或新特提斯洋俯冲的西部动力系统相互作用的中间地带,因此其构造成因及南海海盆打开机制一直存在争论;且构造对南海北部陆缘盆地群的油气成藏有何作用也不甚清晰.本专辑以珠江口盆地为例,特别是以阳江东凹为精细解剖区,结合中国东部新生代盆地的研究成果,展开了以下问...     

Deformation Mechanisms of Darreh Sary Metapelites,Sanandaj‒Sirjan Zone,Iran

The Darreh Sary metapelitic rocks are located in the northeast of Zagros orogenic belt and Sanandaj-Sirjan structural zone. The lithological composition of these rocks includes slate, phyllite, muscovitebiotite schist, garnet schist, staurolite-garnet schist and staurolite schist. The shale is the protolith of these metamorphic rocks, which was originated from the continental island arc tectonic setting and has been subjected to processes of Zagros orogeny. The deformation mechanisms in these rocks include bulging recrystallization (BLG), subgrain rotation recrystallization (SGR) and grain boundary migration recrystallization (GBM), which are considered as the key to estimate the deformation temperature of the rocks. The estimated ranges of deformation temperature and depth in these rocks show the temperatures of 275–375, 375–500, and >500°C and the depths of 10 to 17 km. The observed structures in these rocks such as faults, fractures and folds, often with the NW-SE direction coordinate with the structural trends of Zagros orogenic belt structures. The S-C mylonite fabrics is observed in these rocks with other microstructures such as mica fish, σ fabric and garnet deformation indicate the dextral shear deformation movements of study area. Based on the obtained results of this research, the stages of tectonic evolution of Darreh Sary area were developed.     

Trend Analysis of Polynomial Surfaces and Surface Dynamics (TAPS‒SDs): A Paradigm from (MMT‒NPHMZ) in the Northwestern Himalayas,Pakistan

Geotectonics - Generation and interpretation of geomorphometric maps through remote sensing and GIS techniques are significant platforms for the investigations of neotectonics. This investigation...     

U‒Pb Age of Sphene and the Petrochemical,Mineralogical, and Geochemical Features of Alkaline Rocks of the Bogdo Complex (Arctic Siberia)

Doklady Earth Sciences - In the northern part of the Siberian Platform, east of the Anabar Shield, several massifs of alkaline rocks with carbonatites identified (Tomtor, Bogdo, Promezhutochnyi)...     

Reference Sections of Late‒Middle Neopleistocene Friable Sediments in Kamchatka: Present-Day State and Issue of Age,and Perspectives of Study

Lithology and Mineral Resources - Reference sections of friable sediments in central Kamchatka are studied and their present-day state is described. Previous concepts of the Middle Pleistocene age...     

Tectonic Features and Stages of Evolution of the Baltic–Mezen Shear Zone in the Phanerozoic,Northwestern Russia

Geotectonics - The general tectonic features of the Baltic-Mezen zone developed along the border of the Fennoscandian shield and the Russian Plate in the north of the East European platform, are...     

Tectonic Setting,Emplacement and Petrological Сharacteristics of the Qazan Granitoids: Evidence for the Neo-Tethyan Subduction,Urumieh‒Dokhtar Magmatic Arc,Iran

Geotectonics - The Qazan granitoid pluton (South of Kashan, Iran) is situated in the central part of the Urumieh–Dokhtar Magmatic Arc. The plutonic body includes in its composition...     

Details of Interaction between CaCO3 and Fe at 4 GPa and 1400‒1500°C

Doklady Earth Sciences - The issue of the stability of carbonate matter (CaCO3) in subduction zones under reduced conditions remains topical. In addition, carbonates may be one of the key sources...     

Structural and Geochronological Evidence for Multiple Episodes of Tertiary Deformation along the Ailaoshan-Red River Shear Zone, Southeastern Asia, Since the Paleocene

Structural analyses show that the Ailaoshan-Red River shear zone （ASRRSZ） in Ailao Mountain is composed of three different deformational domains. These domains may represent three episodes of left-lateral slip experienced by the ASRRSZ. The first episode of such deformation occurred throughout the eastern high-grade belt of the ASRRSZ under a transtensional regime and produced L- type tectonites of amphibolite grade. The second episode of left-lateral slip formed high strain zones overprinting the high-grade belt. Its deformational mechanism is similar to simple shear and the deformed rocks are L-S mylonites of greenschist grade. The third episode of left-lateral slip took place chiefly in a western low-grade belt of the ASRRSZ. This deformation occurred in a transpressional regime, formed an overall structure pattern of a sinistral thrust system and produced phyllonites of low-greenschist grade. Geochronological data indicated that the three episodes of left-lateral slip happened before ～58-56 Ma, at least from ～27 Ma to 22 Ma and at ～13-12 Ma respectively. The first episode of slip in the ASRRSZ appeared to correspond to the initial collision of India and Asia at ～60 Ma. The second episode took place almost at the same time as the most intensive compression and uplift in Tibet. The latest event might represent a further eastward material flow in Tibet after ～16-13 Ma. Thus, the ASRRSZ of southeastern Asia probably experienced three main episodes of Tertiary left- lateral slip in the course of intracontinental convergence since the India-Asia collision.     

Tectonic Dynamic Metallization of Silver-GoldHydrothermal Fluids in Proterozoic GneissTerrene Shear Zones, Suichang, Zhejiang, China

-,The well-known Suichang silvengold field is located inZhejiang Province of SOutheast China. It is the largest silver-gold deposit associated with copper and zinc in the Cathaysianmetallogenic province.There are a series of silver-gold dePOsits in the shear zonesof Proterozoic gneiss terrene, Suichang region. The volcanicapparatus at Mesozoic has complicated rpineralization. Respectively, there are two pieces of understanding on the origin ofore-formigg nuid: (l ) metamorphic fluid (Lia…