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1.
本文研究了青海省中奥陶世至早三叠世的牙形剌化石,依据其产出层位自下而上可划分为六个组合Ⅰ中奥陶世 Pygodus anserinus 组合;Ⅱ中—晚泥盆世 Icriodus expansus 组合;Ⅲ早石炭世 Gnathodus bilineatus 组合;Ⅳ晚石炭世 Streptognathodus elegantulus 组合;Ⅴ早二叠世 Sweetognathus whitei 组合;Ⅵ早三叠世 Neospathodus homeri 组合。此牙形剌组合,既丰富了我省古生代及三叠纪的古生物资料,又为相应地层的划分、对比提供了重要依据。  相似文献   

2.
山东聊城地区隐伏的晚古生代含煤地层发育,其中晚石炭-早二叠世太原组灰岩中富含鲢类化石。由三灰、七灰、十灰共鉴定出鲢化石11属45种,自上而下可建立1个鲢类组合带(Pseudoschwagerina带),2个鲢类组合亚带(Triticites paramontiparus亚带;Pseudofusulina firma—Rugosofusulina complicata亚带),该地区所产鲢类组合与华北其他地区及国外相关组合具可比性,Pseudoschwagerina带的时代为早二叠世早期。  相似文献   

3.
山东聊城地区隐伏的晚古生代含煤地层发育,其中晚石炭—早二叠世太原组灰岩中富含类化石。由三灰、七灰、十灰共鉴定出化石11属45种,自上而下可建立1个类组合带(Pseudoschw agerina带),2个类组合亚带(Triticites paramontiparus亚带;Pseudofusulina firma-Rugosofusulina complicata亚带),该地区所产类组合与华北其他地区及国外相关组合具可比性,Pseudoschw agerina带的时代为早二叠世早期。  相似文献   

4.
西宁-民和盆地上第三系十分发育,皆为中新统陆相红层。该统自下而上划分为谢家组、车头沟组、咸水河组和“临夏组”,每组分为二个岩性段。含哺乳动物化石28属37种,介形虫化石15属43种,轮藻化石7属10种及3个孢粉组合;最大出露厚度1595.85m。该统与渐新统马哈拉沟组整合接触,其上被第四系不整合覆盖。哺乳动物呈草原型鼠兔类为主→草原型鼠类与森林型长鼻类、鹿类混生→森林型长鼻类等大量出现并伴生鼠兔类→草原型三趾马动物群的群体演化特征。介形虫为古中国大陆生物区中新世常见属种,轮藻为我国第三纪常见组合;孢粉为草原—森林型组合。  相似文献   

5.
广西百色盆地第三系孢粉化石极为丰富。根据大量孢粉分析鉴定资料,共建立7个孢粉组合及6个亚组合,其时代分别代表早第三纪中-晚始新世、晚始新世、渐新世以及晚第三纪上新世。  相似文献   

6.
末次间冰期-末次冰期柴达木盆地东部气候演化形式   总被引:5,自引:3,他引:5  
柴达木盆地第四系富含介形类化石,介形类生物组合可以反映古气候变化。以盆地东部达参1井中的两种主要介形类(Ilyocypris inermis和Cyprideis torasa)的丰度特征为气候指标,对末次间冰期和末次冰期的盆地气候演变形式进行了恢复。认为柴达木盆地东部末次间冰期和末次冰期的气候演化既有着和全球同步的特点,也有着本区域独自的特征。介形类丰度曲线表明:末次间冰期(MIS5),以Cyprideis torasa为主,整体上为暖型气候,依据介形类特征,又可分为5e,5c.5a三个暖期和5d.5b两个冷期,暖期到冷期都以介形类丰度的大幅突降为特征;末次冰期(MIS4-2)以Ilyocypris inermis为主,整体为冷型气候。其中,早冰阶(MIS4)两种介形类丰度都较低.而间冰阶(MIS3)介形类丰度明显增高,并可划分为3c.3a两个暖期和3b一个冷期。在间冰阶结束之后,介形类大量消失,llyocypris inermis完全灭绝,石盐大范围析出.盆地进入了末次冰期盛冰阶(MIS2)。  相似文献   

7.
山东淄博地区晚石炭世和早二叠世植物化石经笔者鉴定,计有37属104种。本文对当前植物群的组成和性质进行了分析,论证了植物群显示的古气候条件。当前植物群可划分为三个植物组合,即晚石炭世斯氏鳞木—卵脉羊齿 Lepidodendron szeianum—Neuropteris ovata 组合、早二叠世早期中国瓣轮叶—尖头带羊齿 Lobatannularia sinensis—Taeniopteris mucronata 组合和早二叠世晚期三角织羊齿—椭圆斜羽叶 Emplectopteris triangularis—Plagiozamites oblongifolius 组合。  相似文献   

8.
通过汾渭盆地与河南平原地区更新统介形类化石组合的对比,作者认为:黄河东段(三门峡以东)形成的时代为中更新世初期或早更新世末期,里今约七八十万年至一百万年左右。  相似文献   

9.
文章报道合浦盆地9个钻孔中的孢粉资料,共建立3个孢粉组合及8个亚组合,时代分别归古新世、始新世和渐新世  相似文献   

10.
株洲盆地与西峡盆地在晚白垩纪时期同属一个大的山间盆地,本文通过岩相古地理与古生物地层对比,发现两者的上白垩统地层戴家坪组和马家村组具有相似的岩相古地理背景和古生物组合,包括鸭嘴龙类和蜥脚类恐龙骨骼化石及恐龙蛋化石,轮藻化石Charites,Eucypris-Ilyocypris-Talicypridea介形类化石组合以及以蕨类植物孢子Schizaeoisporites占大多数的孢粉组合,这些化石均为晚白垩世代表分子。  相似文献   

11.
本文记述了产于四川龙门山地区中、上泥盆统界线附近观雾山组和土桥子组的四射珊瑚。在大量珊瑚标本鉴定的基础上,建立了中泥盆世晚期至晚泥盆世初期的四个四射珊瑚化石组合。根据四射珊瑚的演化规律,确定以Peneckiella珊瑚类的兴起和Pseudozaphrentis hejiazhaiensis,Temnophyllun(Truncicarinulum)beichua-nensis珊瑚类的消失作为龙门山地区识别中、上泥盆统界线的标志。  相似文献   

12.
Co-occurrence pattern of fish species plays an important role in understanding the spatio-temporal structure and the stability of fish community. Species coexistence may vary with time and space. The co-occurrence patterns of fish species were examined using the C-score under fixed-fixed null model for fish communities in spring and autumn over different years in the Haizhou Bay, China. The results showed that fish assemblages in the whole bay had non-random patterns in spring and autumn over different years. However, the fish co-occurrence patterns were different for the northern and southern fish assemblages in spring and autumn. The northern fish assemblage showed structured pattern, whereas the southern assemblage were randomly assembled in spring. The co-occurrence patterns of fish communities were relatively stable over different years, and the number of significant species pairs in northern assemblage was more than that in the southern assemblage. Environmental heterogeneity played an important role in determining the distributions of fish species that formed significant species pairs, which might affect the co-occurrence patterns of northern and southern assemblages further in the Haizhou Bay.  相似文献   

13.
通过对山东新汶煤田太原组底部徐家庄灰岩发育的有孔虫动物群和牙形石动物群的分析,鉴定出虫筵类有孔虫化石6属14种,非莛有孔虫7属16种,牙形石6属10种,建立一个有孔虫组合:Fusulinella-Fusulina组合;一个牙形石组合:Idiognathodusmagni ficus-Streptognathoduspa...  相似文献   

14.
Surveys were conducted in five voyages in Haizhou Bay and its adjacent coastal area from March to December 2011 during full moon spring tides. The ichthyoplankton assemblages and the environmental factors that affect their spatial and seasonal patterns were determined. Totally 35 and 12 fish egg and larvae taxa were identified, respectively. Over the past several decades, the egg and larval species composition has significantly changed in Haizhou Bay and its adjacent waters, most likely corresponding with the alteration of fishery resources, which are strongly affected by anthropogenic activities and climate change. The Bray-Curtis dissimilarity index identified four assemblages: near-shore bay assemblage, middle bay assemblage and two closely related assemblages(near-shore/middle bay assemblage and middle/edge of bay assemblage). The primary species of each assemblage principally reflected the spawning strategies of adult fish. The near-shore bay assemblage generally occurred in near-shore bay, with depths measuring 20 m, and the middle bay assemblage generally occurred in the middle of bay, with depths measuring 20 to 40 m. Spatial and seasonal variations in ichthyoplankton in each assemblage were determined by interactions between biological behavioral traits and oceanographic features, particularly the variation of local conditions within the constraint of a general reproductive strategy. The results of Spearman's rank correlation analysis indicated that both fish egg and larval abundance were positively correlated with depth, which is critical to the oceanographic features in Haizhou Bay.  相似文献   

15.
Habitat plays a critical role in regulating fish community structure. Using the data collected from a monthly trammel net survey in Ma’an archipelago off the east coast of China, we evaluated impacts of five different habitats(artificial reefs, mussel farms, cage aquaculture, rocky reefs and soft bottom) on fish assemblages. This study suggests that artificial reefs(AR) have significantly higher species richness, abundance and diversity than mussel farms(MF) or soft bottom(SB) habitats during most seasons, and that fish taxa in the AR habitats are similar to those in the rocky reef(RR) habitats. Two different fish assemblage patterns were revealed in the study area using non-metric multidimensional scaling ordination: an assemblage dominated by reef fishes(especially by Scorpaenidae species) in AR, RR and cage aquaculture(CA) habitats and an assemblage dominated by Sciaenidae species in MF and SB habitats. We suggest that reef fishes play a key role in differentiating fish community structures in the study area. Although few differences in fish abundance and diversity were found between the CA and SB habitats, a more diverse age structure was observed in the CA habitats. A much more complex fish assemblage and enhanced population of local species were established as a result of the presence of both floating and fixed artificial structures, probably through improved survival rates.  相似文献   

16.
Assemblages of benthic foraminifera in a sediment core (C02) near the western margin of the southern Yellow Sea Mud were studied to decipher the phase evolution of Holocene paleoenvironmental changes associated with the Holocene marine transgression. It appears that during the early Holocene (11.2–10.1 kyr BP), the faunal was dominated by low salinity and shallow water species Cribrononion subincertum, Buccella frigida and Ammonia beccarii, reflecting a near coast depositional environment. A rapid increase of the relative abundance of Ammonia compressiuscula between 10.1–9.3 kyr BP indicates that the sea level rose rapidly during that time period. From 9.3–7.7 kyr BP, the benthic foraminiferal assemblage was dominated by high percentage of A. compressiscula, suggesting that the sea level was relatively stable. An obvious transition of benthic foraminifera, from the A. compressiuscula-dominated assemblage to an Ammonia ketienziensis-dominated assemblage, occurred between 7.7–6.2 kyr BP, possibly corresponding to a second sea level rapid rise period in the Yellow Sea during the Holocene. This transition may correspond to the gradually strengthened Yellow Sea warm current (YSWC) and finally is established the modern-type circulation in the Yellow Sea. It may also mark the formation of the Yellow Sea cold bottom water (YSCBW) during that period. Since then, the benthic foraminiferal assemblage based on core C02 was dominated by typical YSCBW species, A. ketienziensis, Astrononion italicum and Hanzawaia nipponica, at 6.2–4 kyr BP. A non-deposition period occurred since ~4 kyr BP, which possibly related to the hydrology changes caused by the East Asia monsoon. The two obvious benthic foraminiferal transitions recorded in core C02 during the early and middle Holocene provide evidence that the Yellow Sea has undergone a two-phase rapid sea level rise during the Holocene marine transgression.  相似文献   

17.
In 2012, an artificial reef system was deployed in Xiangshan Bay, China, to enhance its fishery resources. To determine the effect of the artificial reef system on the demersal nekton assemblages, a beforeafter- control-impact study design was applied. Comparisons of assemblages from impact and control habitats revealed that the assemblage in the impact area had a gradual response to reef deployment. The assemblages in the impact and control areas changed in different ways after reef deployment. During the study period, total biomass, species richness and average body weight in the control area remained relatively stable, whereas there were significant increases in these indicators in the impact area. Responses to the reefs differed among nekton species, inducing assemblage succession in the reefs post-deployment. Sparus macrocephalus and Cynoglossus abbreviatus benefited most from reef deployment. Conversely, smallsized shrimp Palaemon gravieri showed a progressive decrease in biomass following reef deployment. Overall, the artificial reef system diversified the demersal nekton assemblage, enhanced the total biomass, and increased the proportion of large-sized species.  相似文献   

18.
To explore the spatial-temporal distribution of the phytoplankton community and evaluate the combined effects of marine resource exploitation, net-collected phytoplankton and physical-chemical parameters were investigated in the Xiangshan Bay during the four seasons of 2010. A total of eight phyla, 97 genera, and 310 species were found, including 232 diatom species, 45 dinoflagellate species and 33 other taxa. The phytoplankton abundances presented a significant (P<0.001) seasonal difference with the average of 60.66×104 cells/m3. Diatoms (mainly consisting of Coscinodiscus jonesianus, Cerataulina pelagica, Skeleto n ema costatum, and genus Chaetoceros) dominated the phytoplankton assemblage in all seasons. We found great spatio-temporal variation in community composition based on the multidimensional scaling and similarity analysis. Canonical correspondence analysis show that temperature, nutrition, illumination, and salinity were the main variables associated with microalgal assemblage. Compared with the previous studies, an increase in phytoplankton abundance and change in the dominant species coincided with increased exploitation activities in this bay (e.g. operation of coastal power plants, intensive mariculture, tidal flat reclamation, and industrial and agricultural development). The present findings suggest that the government should exercise caution when deciding upon developmental patterns in the sea-related economy.  相似文献   

19.
 本文利用美国地质勘查局(USGS)波谱数据库,重建了斑岩铜矿典型蚀变带主要蚀变矿物在ASTER卫星数据对应的反射率曲线,综合分析了主要蚀变矿物的波谱曲线特征,建立了ASTER数据B1、B4、B6、B7和B1、B3、B4、B8主成分分析模型,分别提取典型蚀变带中泥化-绢英岩化类和青磐岩化蚀变矿物组合信息,并以秘鲁南部阿雷基帕省斑岩铜矿区为例,利用研发的技术方法,分别提取了研究区白(绢)云母、高岭石、蒙脱石、明矾石和伊利石等泥化-绢英岩化类蚀变矿物组合信息,绿泥石、绿帘石和方解石等青磐岩化蚀变矿物组合信息。同时结合区域化探资料开展了斑岩铜矿靶区遥感综合找矿预测,经高分辨卫星图像验证,与已知斑岩铜矿床对比表明,本文的方法具有较好的效果。  相似文献   

20.
作者把辽宁本溪田师傅盆地及凤城赛马—阳盆地的早中侏罗世植物群简称田师傅植物群。该植物群由34属77种植物组成。本文是在已确定的名单基础上,着重讨论植物群的性质.组合序列的划分,与同期植物群的比较及其所属地理区和气候带等。田师傅植物群属我国北方锥叶蕨—拟刺葵植物群范围,可划分出早、中、晚3期组合,它与北票、门头沟等植物群最为相似,同属西伯利亚区的中国北方省,反映出温热潮湿的温带或温带—亚热带气候。  相似文献   

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