Comparison of Early Jurassic flora from South Primorye of Russia with its main coeval floras of China

The Early Jurassic flora,with over 42 species of 26 genera and documented in age by sandwiched marine beds,from the Lower Jurassic Schitukhe Formation of South Primorye,Russia,is further reported.The flora is dominated by cycadophytes,ferns and conifers,with some of ginkgoales and czekanowskiales,and characterized by occurrence of Cycadocarpidium,with very rare Coniopteris.A comparison of this flora with its coeval Early Jurassic floras of China is discussed.The Russian flora is considered as the early assemblage of Early Jurassic flora,and more similar to the Early Jurassic floras from the Shansonggang-and Yihe formations of Jilin,Beipiao Formation of Liaoning,and lower-middle Guanyintan Formation of Hunan in China.     

THE FLORISTIC STRUCTURE OF THE XIZANG PART OF THE QINGHAI-XIZANG PLATEAU PLANT SUBKINGDOM

The flora of the Qinghai-Xizang Plateau belongs to the floristic subkingdom of the Holarctic plant kingdom. The Xizang part of this subkingdom can be divided into 4 plant regions. 1) the Yarlung Zangbo River valley region. There are 1,003 species of seed plants, making up 19.38% of the total species in Xizang, and 159 endemic species, 15.89% of the total seed plants. The flora originates mainly from the East Himalayas and the Hengduan Mountains. 2) The Tanggute region. There are 349 species of seed plants and 10 endemic species. The flora represents an intermediate one between the Qinghai-Xizang Plateau and the Hengduan Mountains.3) The Qiangtang region. There are 255 species of seed plants and 18 endemic species. The flora derived from the Himalayan flora and mixed with a great number of Tethysian elements. 4) the Ali region. There are 547 species of seed plants and 41 endemic species. The flora seems to be closely related to Tethysian one.     

Late Cretaceous-Paleogene Palynostratigraphy from the Arkhara-Boguchan Brown Coal Mine of Zeya-Bureya Depression, Russia

1IntroductionThe Arkhara-Boguchan brown coal mine is lo-cated in the western Arkhara depression,southeast-ern part of the Zea-Bureya Basin (Fig.1). Late Creta-ceous-Paleogene coal-bearing strata are well out-cropped at the Arkhara-Boguchan quarry. It contains four coal-bearing beds (in descending order): “Ve-likan”, “Promezhutochny”,“Dvoinoy”and “Nyzhny”, and composed of three sedimentary cycles (Fig.2). The lower cycle can be divided into two sub-cycles:the lowest sub-cycle is …     

A STUDY ON STABILITY OF PHYSICALLY COATED MERCURY FILM ELECTRODE

In this paper, a new method of maintaining the high sensitivity and stability of a physically coated mercury film electrode is proposed, and its mechanism is explained. The polarographic analysis procedure in this method can be simplified, the analysis precision can be raised, and the life of the electrode can be prolonged. The method is practical.     

Stratigraphy of southeastern flanks of Raichikhinsk brown coal field （Zeya-Bureya sedimentary basin）

The results of the palynologic and paleobotanic analyses have allowed determining the Paleocene (including Danian) and Eocene deposits in the series of coal-bearing sediments of southeastern flanks of the Raichikhinsk brown coal field. Their age was corroborated by the palynologic and paleobotanic data. The detailed biostartigraphic data were obtained in the area““ Pioneer““ for the first time. The coal-bearing strata were correlated with those from the sections of the Arkhara-Boguchan brown coal field and the stratotype of the Tsagajan Formation of the Bureya Belogor‘ye.     

Design principle for parameters and interferences of tungsten carbide insert interface on roller bits

The lifetime of roll-bits with inserted tooth will be obviously decreased while drilling in strata and the tungsten carbide can be integrally separated from the roll-cone,which will need more trip out time to replace the roller bit.This study provides an entire analysis on stress as well as strength for teeth and tooth holes in loaded conditions.Qualities of tooth drop from matrix within roller bit.The optimized interferences of teeth inserted into the bit can be reasonably obtained by the critical interference derived from some relevant influence factors on the tooth-fixing quality of roller bits.     

Numerical simulation of water and sand blowouts when penetrating through shallow water flow formations in deep water drilling

In this study, we applied a two-phase flow model to simulate water and sand blowout processes when penetrating shallow water flow(SWF) formations during deepwater drilling. We define ‘sand' as a pseudo-component with high density and viscosity, which can begin to flow with water when a critical pressure difference is attained. We calculated the water and sand blowout rates and analyzed the influencing factors from them, including overpressure of the SWF formation, as well as its zone size, porosity and permeability, and drilling speed(penetration rate). The obtained data can be used for the quantitative assessment of the potential severity of SWF hazards. The results indicate that overpressure of the SWF formation and its zone size have significant effects on SWF blowout. A 10% increase in the SWF formation overpressure can result in a more than 90% increase in the cumulative water blowout and a 150% increase in the sand blowout when a typical SWF sediment is drilled. Along with the conventional methods of well flow and pressure control, chemical plugging, and the application of multi-layer casing, water and sand blowouts can be effectively reduced by increasing the penetration rate. As such, increasing the penetration rate can be a useful measure for controlling SWF hazards during deepwater drilling.     

Boundary of Cretaceous and Paleogene continental deposits in Zeya-Bureya Basin,Amur(Heilongjiang)River region

It was conducted the comparison of palynological assemblages of the Middle Tsagayan,Upper Tsagayan subformations,Furao and Wuyun formations from Zeya-Bureya Basin of Amur (Heilongjiang) River region with assemblages obtained from the marine deposits of Northeast Russia,Sakhalin,Kuril,and Hokkaido Islands,dated by ammonites,foraminifers and other invertebrates. Based on detail correlation,the geological age of the terrestrial beds was defined. The guide fossils are recognized Marsypiletes cretacea,Tricolpites variexi- nus,Aquilapollenites conatus,A. stelkii,A. rombicus,Integricorpus bellum,Pseudointegricorpus clarireticula- tus,Triprojectus amoenus,Orbiculapollis lucidus,Wodehouseia aspera,Quercoidites minor,which had last oc- currence in the late Maastrichtian. The Danian palynofloras usually are dominated by Triatriopollenites plicoides and T. confusus. The species Anacolosidites subtrudens,Aquilapollenites proceros,A. spinulosus have last occurrence in the Danian. The K-T (K-Pg) boundary in the terrestrial deposits is defined in the base of the Upper Tsagayan Subformation and the base of the lower part of the Wuyun Formation. The latter is represented by aleuropelite to fine-grained sandstones. The change of taxonomical composition of palynospectra in similar environments could be determined by real change of flora at the Mesozoic and Cenozoic boundary,but not by changes of lithological facies or depositional environment,generally.     

Discussion on origin of clay minerals in outcropped sandstone from Lower Cretaceous Chengzihe Formation and Muling Formation in Jixi Basin

Clay minerals in the outcropped sandstone from Lower Cretaceous Chengzihe Formation and Muling Formation in Jixi Basin were analyzed by X-ray diffraction. The results show that the clay minerals mainly consist of illite, kaollinite and illite/smectite, which can be divided into two types： kaolinite- and illite/smectite types. The outcropped sandstone occurred in middle diagenetic stage-A on the basis of the clay mineral composition. The development factor of the formation of kaolinite type clay mineral is caused mainly by the organic acid from the coal-bearing formation and nmdstone during the diagenesis process in Lower Cretaceous Chengzihe Formation and Muling Formation in the Jixi Basin. The weak hydrodynamic force of sedimentary facies made the sandstone leaching condition poor, which is the reason forming the aggregation of clay minerals of the illite/ smectite-and illite types.     

Numerical Simulation for Shallow Strata Stability of Coral Reef in the Southwest of Yongshu Reef (South China Sea)

In recent years, infrastructure construction on coral reefs has been increasingly developed. Therefore, the shallow strata stability of coral reefs in the South China Sea should be evaluated. This study aims to investigate the profiles for the shallow strata of coral reefs in the southwest of the Yongshu Reef, particularly in the hydrodynamic marine environment, and to establish a geological model for numerical simulation using Geo-Studio. The shallow strata of the coral reefs include mass gravel, sand gravel, mid-coarse sand, silty sand, fine sand, and reef limestone. The shallow reef slope near the lagoon is similar to a ‘layer cake', in which the side close to the sea is analogous to a ‘block cake'. The simulation results showed that coral reef stability depends on wave loads and earthquake strength and on the physical properties of coral reefs. The factor of safety for the outer reef is greater than 10.0 under static, wave, and seismic conditions; this indicated that the outer reefs were less affected by waves and earthquakes. However, the factor of safety next to the lagoon varied from 0.1 to 5.3. The variation was primarily caused by the thick strata of coral reefs close to the sea(reef limestone, typically with the thickness 10 m and equivalent to a block). The soil and rock layers in the coral reef strata with thicknesses 10 m showed weak engineering geological characteristics. Our findings can provide useful information to future construction projects on coral reefs.     

Early Jurassic Flora and Stratigraphy from Shansonggang of Southern Jilin,China

More than 35 species belonging to 22 genera of fossil plants are recognized by the authors from the Shansonggang flora in the 8hansonggang Basin of Jilin, China. Among them, the coexistence of Coniopteris and Cycadocarpidium demonstrates that the present flora possesses the characters of the early assemblage of Early Jurassic floras in Eurasia. Therefore, the age of the Shansonggang flora is considered the Early Jurassic.This study would be beneficial for better understanding the paleoecological and paleoclimatic characteristics of the Shansonggang Basin. Based mainly on the characters of the flora, the authors suggest that the Lower Jurassic coal-bearing strata, the Shansongang Formation, should namely be renewed.     

Early Jurassic Flora and Stratigraphy from Shansonggang of Southern Jilin,China

1IntroductionThe Shansonggang Basin, one of the Mesozoic coal-bearing basins in northeastern China, is located in southern Jilin Province, China and covering about 30 km2(Fig.1). The basin is lying in the northwest-ern margin of the Longgang anticline, just opposite to the Yihe Basin which lies in the southeastern margin of the anticline. During 1940s~1970 s, a lot of work on the survey of coal geology was made in the basin, but there has been a little knowledge about the plant fossils…     

鲁西石炭、二叠系沉积矿床成矿系列

石炭、二叠系是我国主要含煤地层,它广泛分布于鲁西隆起区。该区上石炭统由本溪组和太原组组成,二叠系下统由山西组和下石盒子组组成,二叠系上统由上盒子组组成。石炭系和二叠系划分出五个成矿系列。本溪组成矿系列主要有 G 层铝土矿,其次是山西式铁矿、硬质耐火粘土矿、软质耐火粘土矿和伴生镓元素。太原组成矿系列主要有煤,其次是膨胀粘土矿、陶瓷“大同土”。山西组成矿系列主要有煤,其次是膨胀粘土矿、菱铁矿。石盒子组万山段成矿系列主要有 A 层硬质耐火耐土矿和铝土矿,其次是铝土矿中伴生镓,石盒子组奎山段成矿系列主要有石英砂岩。这些矿床应归属于“滨海相→滨海沼泽相→内陆沼泽相→内陆湖泊相→内陆河湖相的化学→碎屑岩建造沉积成矿系列”。     

陕西西乡地区志留纪地层的研究

本文根据三个地层剖面,对西乡地区的志留纪地层进行了较为深入的研究。将该地区的志留纪地层划分为龙马溪组和崔家沟组,且首次建立起该地区志留纪的生物地层系统——笔石分带。但龙马溪组底部的笔石带则属奥陶纪。还将西乡地区的志留系与国内外有关的几个地区的志留系进行了对比。     

Stratigraphy of southeastern flanks of Raichikhinsk brown coal field (Zeya-Bureya sedimentary basin)

The results of the palynologic and paleobotanic analyses have allowed determining the Paleocene (including Danian) and Eocene deposits in the series of coal-bearing sediments of southeastern flanks of the Raichikhinsk brown coal field. Their age was corroborated by the palynologic and paleobotanic data. The detailed biostartigraphic data were obtained in the area"Pioneer" for the first time. The coal-bearing strata were correlated with those from the sections of the Arkhara-Boguchan brown coal field and the stratotype of the Tsagajan Formation of the Bureya Belogor'ye.     

山东淄博地区晚古生代植物群组合特征及有关地层划分问题探讨

山东淄博晚古生代地层出露较好,发育较全,植物化石较为丰富,是研究华北晚古生代含煤地层最好的地区之一。本文对该区晚古生代植物群做了初步研究。根据植物的演替和组合特征,共建立七个化石组合带,用以解决本地区石炭二叠纪地层划分、对比与时代问题。同时,从植物群角度,着重对当前分歧较大的华北石炭、二叠系分界和二叠系上、下统分界的确定以及界线划分原则,提出了自己的见解。     

宁阳煤田茅庄井田煤系地层特征和成煤环境分析

通过对宁阳煤田茅庄井田煤系地层综合分析,揭示了茅庄井田的煤层岩性特征和沉积环境。研究结果表明:该井田主要含煤地层为早二叠世山西组和晚石炭世—早二叠世太原组,总厚度约220 m。可采或局部可采者4层,即3上煤层,3下煤层,16煤层、17煤层,平均总厚度为9.52 m。本井田内3上煤层、3下煤层为主采煤层。含煤地层为石炭—二叠纪月门沟群,其中山西组是该区最重要的含煤地层。沉积环境为从海相沉积为主到以陆相沉积为主的转变过渡时期,岩石地层反映了典型的海陆交互相的沉积特征;在海陆交互期海退三角洲平原上供应了大量的泥炭沼泽,为茅庄井田煤层提供了物质基础。其中太原组为典型的海陆交互相沉积,沉积相环境稳定,变化小,标志层及煤层层位清楚、稳定,煤层沉积层序规律性强,是区域地层对比的稳定层位。     

The First Discovery of the Earliest Devonian Conodont Zonal Fossil from the "Gavuu Member" in Mushgai Area of South Gobi,Mongolia

Conodont Caudicriodus woschimidti woschmidti has been found from a big outcrop (hill) of the Bayan-Kho-shuu Ruins Section which was previously assigned to the Silurian Gavuu Member of the Mandalovoo Formation. This isfirst time to find the lowermost Devonian conodont zonal fossil in Mongolia. The lower part of the Gavuu Member is Silurian. But the strata from where we collected samples M-9～M-12 definitely belong to Lower Devonian (lower Lochko-vian) rather than Lower Silurian. The Mandalovoo Formation should be named Mandalovoo Group, and its three members should be changed into three formations.     

中国东北地区晚侏罗世聚煤规律研究

中国东北地区晚侏罗世煤盆地有内陆断陷山间(或山前)盆地和滨海山间断坳盆地两种。内陆盆地具同一演化过程;含煤地层中部深水湖泊相的上、下均含有煤层。滨海盆地另具同一发展过程;含煤性与盆地基底结构、海水进退息息相关。