Changes of taxonomical composition of Late Jurassic Early Cretaceous palynofloras of Bureya Basin,Russia

The changes of taxonomical composition of the Late Jurassic-Early Cretaceous palynofloras are revealed,in the upper stream of Bureya River in Bureya Basin.The palynofloras are dominated as follows:the Berriasian one by ferns (Cyatheaceae,Dicksoniaceae,Osmundaceae), Classopollis and bisaccate pollen;the Valanginian-Hauterivian one by ferns (Cyatheaceae,Dicksoniaceae), Ginkgocycadophytus and bisaccate pollen;the Barremian one by ferns(Cyatheaceae,Dieksoniaceae);the Aptian one by ferns(Cyatheaceae,Dieksoniaceae,Gleicheniaceae)and Ginkgocycadophytus;and the Albian one by ferns(Schizaeaceae)and bisaccate pollen.In the Albian the floral diversity raises with the angiosperms appearing.     

Changes of taxonomical composition of Late Jurassic-Early Cretaceous palynofloras of Bureya Basin,Russia

The changes of taxonomical composition of the Late Jurassic-Early Cretaceous palynofloras are revealed,in the upper stream of Bureya River in Bureya Basin.The palynofloras are dominated as follows:the Berriasian one by ferns(Cyatheaceae,Dicksoniaceae,Osmundaceae),Classopollis and bisaccate pollen;the Valanginian-Hauterivian one by ferns(Cyatheaceae,Dicksoniaceae),Ginkgocycadophytus and bisaccate pollen;the Barremian one by ferns(Cyatheaceae,Dicksoniaceae);the Aptian one by ferns(Cyatheaceae,Dicksoniaceae,Gleicheniaceae) and Ginkgocycadophytus;and the Albian one by ferns(Schizaeaceae) and bisaccate pollen.In the Albian the floral diversity raises with the angiosperms appearing.     

Palynoflora of Wulaga dinosaur site in Jiayin （ Zeya-Bureya Basin,China）

The palynological assemblage from Wulaga dinosaur site in Jiayin from southeastern Zeya-Bureya Basin was studied. The high content of pteridophytes spores is characteristic for this assemblage. The further characters are in decrease of abundance-tricolpate pollen, Ginkgocycadophytus, pollen of Taxodiaceae, Cupressaceae and Taxaceae （TCT） , bisaccate pollen of Pinaceae, and triporate pollen. The bone-bearing burials of Wulaga dinosaur site formed under conditions of vast swampy river valley covered by ferns and taxodialeans. Tricolpate pollen, produced by plants, close to those of Platanaceae, Fagaceae, Betulaceae, and Juglandaceae, counts in favor of valley river open canopy forests.     

Palynoflora of Wulaga dinosaur site in Jiayin （ Zeya-Bureya Basin, China）

The palynological assemblage from Wulaga dinosaur site in Jiayin from southeastern Zeya-Bureya Basin was studied. The high content of pteridophytes spores is characteristic for this assemblage. The further characters are in decrease of abundance-tricolpate pollen, Ginkgocycadophytus, pollen of Taxodiaceae, Cup ressaceae and Taxaceae ( TCT) , bisaccate pollen of Pinaceae, and triporate pollen. The bone-bearing burials of Wulaga dinosaur site formed under conditions of vast swampy river valley covered by ferns and taxodialeans. Tricolpate pollen, produced by plants, close to those of Platanaceae, Fagaceae, Betulaceae, and Juglandaceae, counts in favor of valley river open canopy forests.     

Lipovtsy flora of Razdolnaya( Suifun) River Basin,Primorye region,Russia

The Lipovtsy flora originates mostly from the synonymous Formation exposed at the coal quarries in the Razdolnaya( Suifun) River Basin in Heilongjiang Province( China) and Primorye Region( Russia). The thorough study of this flora has revealed its high diversity and abundance. One of the most prominent groups in the Lipovtsy flora is the ferns. Next in diversity are conifers( Miroviaceae,Taxodiaceae,Podozamitaceae,Taxaceae,Cephalotaxaceae). It was revealed the remarkable quantity of bennettitalean remains( 24 taxa). The main peculiarity of this flora is the appearance of first angiosperms( pollen,dispersed cuticle,leaves). The fine preservation of the cuticles from the coals allows us to research the taxonomical composition of peat-forming plants and clear main components of the swamp plant communities. These plants supplied the material for the accumulation of resinite coals on the territory of Razdolnaya River Basin were conifers Miroviaceae,taxodialeans,bennettites,as well as gleicheniaceous and cyatheaceous ferns.     

Diversity,endemism and conservation of ferns (Polypodiales) in the Mexican Mountain Component

We analyzed the distributional patterns of 95 selected species of leptosporangiate ferns inhabiting the Mexican Mountain Component, using grid-cells of one geographical degree as unit areas, applying endemism indices and richness and beta diversity analyses. Distributional data were obtained from several herbaria and specialized literature. Five grid-cells appear to be important for fern species richness, as they contain 35 to 49 species. These grid-cells are located in the Sierra Madre Oriental (SMO), Trans-Mexican Volcanic Belt (TMVB) and the Sierra Madre del Sur (SMS). Mean richness by latitudinal belts of one degree showed that the belts with highest values are related to the TMVB and SMS. A total of 13 grid-cells were recognized as important from the perspective of endemism; most of them are located also in the SMO, TMVB and SMS. The richest gridcells coincided with one of the main centres of endemism for ferns obtained in this study, located in the convergence of the southern part of the SMO, the eastern portion of the TMVB and the northern part of the SMS, reflecting the high humidity existing on the mountain slopes facing the Gulf of Mexico. Some important grid-cells recognized from richness and endemism analyses coincide with Mexican Natural Protected Areas. The beta diversity analysis showed a low degree of similarity among grid-cells, implying a high species replacement, as the result of environmental heterogeneity occurring in the Mexican mountain systems. On the other hand, the spatial analysis suggested a pattern of phytogeographical regionalization comprising two main areas: the Mexican Transition Zone and the Mexican Central Plateau. Ferns play an important role in the Mexican biodiversity and contributing to the beta diversity of Mexico.     

Sedimentological features and biostratigraphy of Jurassic/Cretaceous deposits in continental basins in Priamurie, Far East Russia

The paper describes the sedimentary features and biostratigraphy of the transitional Jurassic to Cretaceous deposits in the continental basins of Priamurie formed after the collision between the Siberian and North China blocks. In Upper Priamurie, the collision occurred in the late Early Jurassic as dated by the emplacement of the post-collisional granites (191Ma) . While in Lower Priamurie and West Priokhotie it could take place in the late Middle Jurassic on the basis of fossil evidence from an accretionary turbidite complex. This event reflected the environmental change from coastal-marine to alluvial plains, often boggy, where coals accumulated. The environmental change is in harmony with that of biota. Systematic study of floral and spores/pollen assemblages, particularly in the sections of interbedded marine and non-marine deposits, makes clear the chronostratigraphic succession of floral associations and shows the possibility of their application for subdivision and correlation of the continental deposits of Priamurie. The coastal-marine environment of the residual post-collisional sublatitudinal basins in the western part of Priamurie (Upper Amur and Dep basins) was replaced by the continental in the late Middle Jurassic and in the eastern part in the Berriasian-Valanginian ( Torom Basin) . Similar environmental change commenced in the submeridional rift basins: the Bureya Basin in the Callovian and the Partizansk Basin in the Hauterivian. Changes in ecosystems occurred frequently during theMiddle Jurassic-Neocomian, but the most substantial changes took place in the late Middle Jurassic and in the end of Late Jurassic.     

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.     

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.     

Relationship between surface pollen and modern vegetation in Southwestern China

Based on the pollen data obtained from thirty-five surface soil samples and investigated vegetation data from seven plant quadrats, the quantitative relationship between surface soil pollen and modern vegetation are studied in the longitudinal range-gorge region (LRGR) in Southwestern China. R-values (referring to pollen assemblages) are calculated with pollen percentage and plant abundance. The coefficients of similarity between pollen and vegetation are analyzed. The results show that the pollen assemblages on surface soil of all vegetation zones can basically represent the native vegetation, but the pollen assemblages are not fully according with the vegetation. This is due to the influencing factors including pollen preservation ability, pollen production, amount of exotic pollen and pollen identification. The pollen representation in surface soil is different in families and genera. The pollen of woody plants such as Pinus, Tsuga, Alnus, Fagus and Castanopsis are over-representative, but those of Quercus, Carpinus Myrica, Elaeocarpaceae, Ericaceae, Theaceae and Llex are underrepresentative; the pollen of herbaceous plants such as Artemisia and Rubiaceae are over-representative, while those of others including Gramineae and Araliaceae are under-representative. The R-values of the same taxon pollen in different vegetation zones are different, depending on their distances from the pollen sources. The coefficients of the similarity between plant communities and pollen assemblages are mostly over 70%, which indicate again that the surface soil pollen and spores assemblages can represent the vegetation. It is concluded that there is a good corresponding relationship between surface pollen assemblages and native vegetation in LRGR, and it is of great significance for reconstructing the past vegetation and paleoclimate using quantitative fossil pollen data in this region.     

融合植被遥感数据的北京市次日花粉浓度预测

中国国土绿化状况公报指出,2010—2020年中国许多城市的绿化面积增加、绿化质量提高,可随之而来的影响人体健康的致敏性花粉风险也逐渐提高。本文利用遥感手段获得北京市乔木和草地生长区域平均植被叶面积指数（LAI）时间序列作为植被物候信息,并将其作为花粉浓度预测因子之一,结合日气象数据,使用具有外部输入的非线性自回归神经网络模型（NARXnet）,进行北京市次日花粉浓度的预测。结果显示：① 通过逐步回归计算,对于春季数据,日均气温3日平滑,积温,叶面积指数（LAI）和叶面积指数一阶导为次日花粉浓度预测的关键变量;对于秋季数据,日均气温、平均风速、最低日气温、日均气温3日平滑、积温和叶面积指数（LAI）为次日花粉浓度预测的关键变量;② 加入遥感物候信息可显著地提高NARXnet模型的春秋时段的花粉浓度的预测精度。使用本文提出的结合叶面积指数的NARX模型后,预测模型的总体精度为71%。由此,本研究认为在原有气象因子的基础上,辅之以用遥感技术手段获取的大面积植被物候信息,如叶面积指数动态,可作为预测次日花粉浓度的一种有效手段。     

毛塞几比盆地外陆架-陆坡区阿尔比阶-土伦阶沉积特征及成藏体系

近几年来,多个大型油气发现使得毛塞几比盆地成为国际油气勘探的热点区域。基于地震资料和钻测井资料系统开展了沉积相以及沉积模式研究、储层物性分析、烃源岩评价以及成藏体系分析工作。研究结果表明:①盆地中南部外陆架广泛发育多期强制海退三角洲沉积体系,受基准面旋回控制,强制海退三角洲顶积层遭受剥蚀,砂体被搬运到三角洲前部,形成强制海退砂,砂体在陆架边缘附近广泛分布;陆坡类型控制了深水扇差异分布模式,南部断控型陆坡控制了深水扇的分布,深水扇主体发育在陆坡坡脚,距离陆架边缘较近,北部平缓型陆坡下重力流搬运较远,深水扇主体远离陆架边缘,据此建立了南部断控型陆坡控砂模式和北部缓坡型陆坡富砂模式。②外陆架强制海退三角洲和北部缓坡型深水扇储层条件好,测试产能高,受胶结作用和滑塌碎屑影响,南部陡坡型深水扇储层物性差。③油源对比表明,油气主要来自下白垩统阿普第阶-阿尔比阶与上白垩统赛诺曼阶-土伦阶海相烃源岩,阿普第阶-阿尔比阶烃源岩以Ⅱ₂型干酪根为主,主要生气;赛诺曼阶-土伦阶海相烃源岩以Ⅰ型干酪根为主,主要生油。④研究区发育3套有利成藏体系,分别为阿尔比阶陆架边缘成藏体系、阿尔比阶-土伦阶陆坡坡脚成藏体系以及赛诺曼阶陆坡远端成藏体系,其中陆架边缘成藏体系与陆坡远端成藏体系勘探潜力更大,是下一步勘探的重点。      

Sedimentary records of mangrove evolution during the past one hundred years based on stable carbon isotope and pollen evidences in Maowei,SW China

Mangroves accumulate sedimentary sequences, where cores can provide historical records of mangrove evolution with past climate change and human activity. The study traced the history of mangrove evolution during the past one hundred years in a mangrove swamp of Maowei Sea, SW China. The sedimentation rates(0.38-0.95 cm yr~(-1)) were calculated on the basis of ln(~(210)Pb_(xs)/Al) and mass depth in the core sediments. Chemical tracers, such as δ~(13)C_(org) and C:N values, were utilized to trace the contribution of mangrove-derived organic matter using a ternary mixing model. Because of potential diagenetic alteration and / or overlap in the isotopic signatures of different components, simultaneous use of mangrove pollen diagrams can help to supplement some of these limitations. Combined with mangrove pollen, mangrove evolution was reconstructed and could be divided into three stages: flourishment(1886-1905 AD), slight degradation(1905-1949 AD) and rapid degradation period(1949-2007 AD), which was consistent with previous reports. The reclamation of mangrove swamps to shrimp ponds was the major reason for rapid degradation of mangrove ecosystems in recent years, rather than climate change in the region.     

Preliminary study on the spore-pollen assemblages found in the Cenozoic sedimentary rocks in Grove Mountains, east Antarctica and its climatic implications

Glaciogene sedimentary rocks have been found in modem tills of the Grove Mountains, east Antarctica during the 1998 - 1999 Chinese National Antarctic Research Expedition （CHNARE）. Based on the lithilogic and sedimentary features, these sedimentary rocks are correlated with Cenozoic sedimentary strata of the Pagodroma Group in the neighboring Prince Charles Mountains and the Sorsdal Formation in VestFold Hills. Sedimentary clasts contain sparsely Late Tertiary spores and pollens, including ： Toroisporis （ Lygodiaceae）, Osmunda, Granulatisporites （ Pteridaceae？） , Polypodiaceae, Podocarpus , Araucariaceae, Artemisia , Rhus , Nothofagidites , Proteacidites （Proteaceae） , Quercus , Fraxinoipollenites （ Oleaceae ） , Oleoidearumpollenites（ Oleaceae ）, Operculumpollis, and Tricolpopollenites. Most of the pollen and spores contained in these samples originate from local sources according to the conditions of their preservations as well as correlations with the microfossil assemblages found in the neighboring areas. The majority of the pollen assemblages, as represented by Podocarpus and Nothofagus, belong to the Weddellian biogeocenose, however some exotic components from the old sedimentary basement rocks may have been included during erosion of the proximal ice sheet. If the source areas of glaciogenic sedimentary rocks that bear the pollen and spores are assumed to be local, or in the up glacier areas, the pollen assemblages in these samples might represent an inland flora during a warmer period of the ice-sheet evolutionary history. The finding of the Artemisia and Chenopodiaceae in the pollen assemblages implies that they may belong to late Tertiary （most probably Pliocene）. The absence of diatoms in the samples analyzed may indicate that there are no Cenozoic marine strata in the interior of the east Antarctica beyond the Grove Mountains. The significances of the finding of the Nothofagus in these pollen assemblages are discussed on the basis of current knowledge about the age, distribution and ecological conditions of this kind of fossils found in Sirius Group or other strata outcropped in Antarctica. As a preliminary conclusion, we think that the existence of the Cenozoic glaciogenenic rocks and their pollen assemblages present new evidence for a large scale glacial retreat history in Grove Mountains of east Antarctica, and thus support a dynamic East Antarctic Ice Sheet （EAIS）. This is consistent with the interpretations of Webb et al. （1984）.     

Reanalysis of principal component analysis to resume past vegetation and environment

In the paper 11 pollen types were selected from the original pollen and spore records of 54 samples in Fenzhuang profile of Beijing region, then 54 × 11 matrix was set up. Based on the pollen data of Fenzhuang profile from the Late Pleistocene to the Early Holocene, the paper gives a further analysis to subdivide zone of the pollen assemblages and changes of paleovegetation and paleoenvironment in this area using principal component analysis (PCA). PCA can play an complementary role for subdividing zone, at the same time, it can eliminate the difference to subdivide zone of the pollen assemblages caused by artificial factors. Finally to the biodiversity in plant communities and complex geographical environment in Beijing region, using great dispersal of accumulative percent of total in PCA (for cumulative rate only 57% from the first three factors of PCA), may sufficiently correspond to the environmental characteristic, so as to recover past climate condition much better. Supported by National Natural Science Foundation of China (No. 49571066, 39470132).     

Reanalysis of principal component analysis to resume past vegetation and environment

In the paper 11 pollen types were selected from the original pollen and spore records of 54 samples in Fenzhuang profile of Beijing region, then 54 × 11 matrix was set up. Based on the pollen data of Fenzhuang profile from the Late Pleistocene to the Early Holocene, the paper gives a further analysis to subdivide zone of the pollen assemblages and changes of paleovegetation and paleoenvironment in this area using principal component analysis (PCA). PCA can play an complementary role for subdividing zone, at the same time, it can eliminate the difference to subdivide zone of the pollen assemblages caused by artificial factors. Finally to the biodiversity in plant communities and complex geographical environment in Beijing region, using great dispersal of accumulative percent of total in PCA (for cumulative rate only 57% from the first three factors of PCA), may sufficiently correspond to the environmental characteristic, so as to recover past climate condition much better.     

Palynological assemblages from the holocene sediments of the Changjiang (Yangtze) River Delta and its implications

The palynolpgical study on the Quaternary sediments of 42 cores in the region of the Yangtze River Delta and the sections of 4 relics had been done since 1960. Palynological assemblages from the region of the Yangtze River Delta, showing obviously .common characteristics but with slight differences because of the vast areas covered, can be divided into five spores and pollen zones and three subzones in ascendant order:I.Quercus alienc-Pinus-Cupressaceae-Chenopodiaceae spores and pollen zone reflecting the cool, then cold and dry climate--Preboreal.II.Quercus dentata-Quefcus acutissima-Pinus-Castanea-Artemisia spores and pollen zone reflecting the temperate and cool, but a little dry climate--Boreal.III.Quercus glauca-Caslanopsis-Myrica-Caslanea spores and pollen zone reflecting the hot and moist climate--Atlantic.IV.Quercus acutissima-Pinus-Castanea-Quercus glauca- Chenopodiaceae spores and pollen zone reflecting the warm, and a little dry climate--Subboreal.V.Quercus acutissima-Costarica-Quercus glauca     

Loss of preferred habitat and pollen limitation threatens reproduction in a rare mountain Paeonia delavayi

Paeonia delavayi is a wild tree peony species endemic to high-altitude regions in southwestern China.Recent agricultural land expansion,however,not only causes its dwindling population size,but also poses a severe threat to its long-term persistence.Since our knowledge of the reproductive biology of P.delavayi is very limited,and some management misconceptions have further exacerbated the already worrisome situation,the aim of the present study is to provide some scientific evidence regarding habitat preference and breeding system of P.delavayi,and to help correct some management misconceptions.Specifically,morphological traits of P.delavayi populations growing in two different habitats(i.e.,the open area versus forest understory),including basal stem diameter,plant height and flower numbers per plant,were measured and compared with each other.A range of floral manipulation experiments was further conducted to study the extent of self-compatibility and pollen limitation.The results showed that P.delavayi preferred the open habitat over forest understory as it generally grew bigger with thickerstems,and produced a higher number of flowers in the former habitat.Therefore,the open habitat should receive immediate priority for conservation action instead of being converted to agricultural land;also,P.delavayi is pollen limited,as evidenced by the fact that experimental flowers receiving supplemental non-self pollen generally displayed elevated seed production than flowers subjected to other treatments(e.g.,non-supplemental self pollen,non-supplemental non-self pollen and supplemental self pollen),which is consistent with reported observations that alpine plants are more likely to be pollen-limited than lowland plants.We suggest that human intervention might be necessary to guarantee the long-term persistence of P.delavayi as harsh alpine environment,intense competition for pollinators and different anthropogenic perturbations co-limit its reproductive success.