Geochemical Stratigraphy and Microvertebrate Assemblage Sequences across the Silurian/Devonian Transition in South China     

ZHAO Wenjin  WANG Nianzhong  ZHU Min  Ulrich MANN  Ulrich HERTEN  Andreas LüCKE 《《地质学报》英文版》2011,85(2):340-353

Carbon isotope (δ13Corg) analyses of non-marine clastic rocks and neritic carbonates and black shales spanning the Silurian/Devonian transition are compared from two richly fossiliferous sequences in Qujing of East Yunnan and Zoige of Sichuan, South China. The two sections, Xishancun and Putonggou sections in South China, reveal positive δ13Corg shifts happening in the Upper Pridoli and Lower Devonian and reaching peak values as heavy as ?25.2‰ (Xishancun) and ?19.9‰ (Putonggou) in the lowermost Lochkovian following the first occurrence of the thelodont Parathelodus and the conodont Icriodus woschmidti woschmidti (only in Putonggou Section and together with Protathyris-Lanceomyonia brachiopod fauna). These results replicate a globally known positive shift in δ13Corg from the uppermost Silurian to the lowermost Devonian. The δ13Corg variations across the Silurian/Devonian Boundary (SDB) at the two sections in South China exhibit a shift in carbon isotopic composition similar to the detailed SDB curves from the borehole Klonk-1 drilled at top of the Klonk Global Standard Stratotype-Section and Point (GSSP) in the Prague Basin, Czech Republic. In addition, four microvertebrate assemblages, including the Liaojiaoshan, Xishancun, Yanglugou and Xiaputonggou assemblages, are recognized from the Silurian/Devonian transition exposed in the Xishancun and Putonggou sections, respectively. The results from both carbon isotope stratigraphy and microvertebrate assemblage sequences suggest that the SDB in South China is located at the base of the Xishancun Formation (between sample QX-20 and sample QX-21) in the Xishancun Section and the lower part of the Xiaputonggou Formation (between sample ZP-09 and sample ZP-10) in the Putonggou Section. The isotopic trend for organic carbon together with the changes of microvertebrate remains across the SDB can offer an approach to a potential correlation of the SDB from different sedimentary facies, which help to correlate the marine with non-marine deposits.  相似文献   

Formation Mechanism of High Quality Marine Source Rocks—Coupled Control Mechanism of Geological Environment and Organism Evolution     

腾格尔  胡凯  孟庆强  黄娟  付小东  谢小敏  仰云峰  高长林 《中国地质大学学报(英文版)》2011,(3)

High quality marine source rock (HQMSR) is the key prerequisite for medium to large hydrocarbon accumulations. However, the forming mechanism remains unclear. On the basis of the in-vestigation for the geodynamic setting of the Middle-Upper Yangtze during the Early Cambrian in dif-ferent spatial scales and the analysis of trace elements, the main controlling factors of the development of high quality marine source rock are discussed, with specific consideration of the burial rate of the organic matter. The ...  相似文献   

藏南地区晚白垩世岩相古地理初步研究     

熊国庆  江新胜  伍皓 《古地理学报》2011,13(4):387-396

通过对藏南地区上白垩统沉积特征及沉积相进行综合分析,初步地恢复了该地区晚白垩世岩相古地理.该地区自南向北沉积水体逐步变深,沉积相带展布依次为滨海相、浅海陆棚相(外陆棚和内陆棚亚相)、大陆斜坡相及深海盆地相,局部地区浅海陆棚相之上发育碳酸盐岩礁滩相和孤立台地相等.盆地性质总体上仍然为被动大陆边缘海盆,但已具备周缘前陆盆地...  相似文献   

上海地学研究：从长江口到深海——中国科学院院士汪品先教授接受本刊专访     

《上海国土资源》2011,32(3):1-6

2011年8月30日下午,本刊主编、上海市地质调查研究院总工程师严学新教授,本刊编辑部主任、上海市地质调查研究院总工程师办公室副主任龚士良教授,在同济大学海洋与地球科学学院杨守业教授的陪同下,拜访了中国科学院院士、同济大学海洋与地球科学学院汪品先教授,并作了专题访谈。  相似文献   

Effect of UV-B radiation on the population dynamics of the rotifer Brachionus urceus     

WANG Jinhe  FENG Lei  TANG Xuexi 《海洋学报(英文版)》2011,30(2):113-119

The effect of UV-B radiation enhancement at experimental doses of 0.00,0.24,0.48,0.72,0.96,and 1.20 kJ/m 2 on the population dynamics of the rotifer Brachionus urceus feeding on the alga Chlorella sp.was studied under controlled laboratory conditions using clonal culture and life-table techniques.The results show that UV-B radiation treatment significantly shortened the survival time of the rotifer (P <0.05): The longest survival time (336 h) occurred in the control (0.00 kJ/m 2 ) while the shortest (222 h) occurred when exposed to the highest UV-B radiation treatment (1.20 kJ/m 2 ).The fecundity of the rotifer B.urceus was enhanced by the lower UV-B radiation treatment (0.24 and 0.48 kJ/m 2 ) but inhibited by the higher treatments (0.96 and 1.20 kJ/m 2 ).Life expectancy also was obviously affected by UV-B radiation (P <0.05).The highest life expectancy occurred in the control (0.00 kJ/m 2 ),and it became shorter with increasing doses of UV-B radiation.The resutls in the present study indicate that the life expectancy of the rotifer B.urceus can be used as an indicator for UV-B radiation enhancement.  相似文献   

Dark respiration in the light and in darkness of three marine macroalgal species grown under ambient and elevated CO₂ concentrations     

ZOU Dinghui  GAO Kunshan  XIA Jianrong 《海洋学报(英文版)》2011,30(1):106-112

Dark respiration (non-photorespiratory mitochondrial respiration),which occurs both in the light and in darkness,is vital for growth and survival of algae and plays a critical role in modulating the carbon balance of them.In the present study,we have investigated dark respiration in the light (R L) and in darkness (R D) in three marine macroalgal species,Hizikia fusiformis (phaeophyta),Gracilaria lemaneiformis (Rhodophyta) and Ulva lactuca (Chlorophyta),cultured at 20℃ using aeration with two CO 2 conditions:current ambient (CO 2 concentration about 380 μl/L) and elevated CO 2 (approximately 720 μl/L) air.R L was estimated by using the Kok method,whereas R D was determined as the rate of O 2 influx at zero light.The results showed that both R L and R D were unchanged for the elevated CO 2-grown algae relative to ambient CO 2 concentration for all the algal species tested.However,R L was significantly lower than R D across all the algal species and growth CO 2 treatments,demonstrating that daytime respiration was partly depressed by the light.The percentage of inhibition of respiration by light was similar between ambient and elevated CO 2 grown algae.The ratio of respiration to photosynthesis,which tended to decrease when estimated using R L instead of R D,was not altered for the elevated relative to ambient CO 2 concentration.The results suggest that R L,rather than R D,is a more accurate estimate of nonphotorespiratory carbon loss in marine macroalgae during the daytime.It would not be anticipated that elevated atmospheric CO 2 would exert a substantial influence on respiratory flux either in the light or in darkness in these particular marine macroalgal species.  相似文献   

Sedimentological criteria to differentiate submarine channel levee subenvironments: Exhumed examples from the Rosario Fm. (Upper Cretaceous) of Baja California, Mexico, and the Fort Brown Fm. (Permian), Karoo Basin, S. Africa     

Ian A. Kane  David M. Hodgson 《Marine and Petroleum Geology》2011,28(3):807-823

Two scales of levee confinement are commonly recognised from submarine channel-levee systems on the seafloor and in the subsurface. Large-scale external levees bound the entire system whilst smaller-scale internal levees bound individual thalweg channels within the channel-belt. Although thin beds are commonly identified in core and well logs, their origin, and consequently their stratigraphic significance is currently poorly understood. This knowledge gap stems, in part, from the lack of unambiguously identified outcrop analogues of channel-levees, and in particular the lack of identifiable internal and external levees. Here we report from two exhumed channel-levee systems where both scales of confinement can be recognised: the Rosario Fm. of Baja California, and the Fort Brown Fm. of South Africa. A suite of characteristic sedimentary features are recognised from internal and external levees respectively: internal levees are characterised by structures indicative of complexity in the waxing-waning style of overspill, interactions with topography and flow magnitude variability; in contrast, external levees are characterised by structures indicative of simple surge-like waning flows, relatively uniform flow directions, laterally extensive beds, and a lack of erosive events. Using these observations, together with published literature, we propose a simple nomenclatural scheme for levee sub-environments, and criteria to differentiate between levee sub-environments in core or outcrop.  相似文献   

The role of international environmental instruments in enhancing transboundary marine protected areas: An approach in East Africa     

José Guerreiro  Aldo Chircop  David Dzidzornu  Catarina Grilo  Raquel Ribeiro  Rudy van der Elst  Ana Viras 《Marine Policy》2011

The increasing degradation of marine ecosystems has led to multiple calls for greater protection through the establishment of marine protected areas (MPAs). If created at the ecosystem or ecoregion level, MPAs will likely straddle maritime boundaries and therefore necessitate international cooperation. International environmental law and international law of the sea may facilitate cooperation between States in creating transboundary MPAs. The extent to which this body of law is actually or potentially useful for the establishment of transboundary MPAs is examined in the context of the East African Marine Ecoregion, focusing on Mozambique, South Africa, and Tanzania. A general survey and assessment of the applicable global, regional, and bilateral instruments in relation to the three States is conducted. Although some global instruments are relevant in the East African context, regional and bilateral instruments are more conducive to the establishment of transboundary MPAs. The article concludes that although a trilateral agreement between Mozambique, South Africa, and Tanzania would be an ideal vehicle for the establishment of a transboundary network of MPAs addressing both national and ecoregional conservation interests, a separate solution at each border will be the first step towards this goal.  相似文献   

湄洲湾多毛类物种多样性及生态特点     

方少华  张跃平  骆巧琦  吕小梅 《台湾海峡》2011,30(3):419-429

于2007年5月至2010年5月间,在湄洲湾海域设置50个浅海测站,16条软相潮间带断面,进行底栖生物调查,根据调查采获的多毛类动物样品进行整理,研究湄洲湾多毛类物种多样性及生态特点．湄洲湾海域共鉴定有多毛类环节动物177种,隶属4l科112属．湄洲湾多毛类的动物区系特点与台湾海峡具有相似的热带、亚热带特征．讨论多毛类环节动物在调查区域底栖生物种类及数量组成中的地位,分析调查区域多毛类多样性指数等生态特征,为湄洲湾的生态环境监控、环境保护提供多毛类生态学的资料．  相似文献   

盐度对日本鳗鲡生长及非特异性免疫酶活性的影响   总被引：2，自引：0，他引：2  

胡利华  闫茂仓  郑金和  李小勇  黄贤克  王侃  周朝生 《台湾海峡》2011,30(4):528-532

利用实验生态学和酶学方法,在浙江省海洋水产养殖研究所清江试验场研究了盐度对平均体长为25．1±5．6cm的日本鳗鲡（Anguillajaponica）生长及其血清溶茵酶（LZM）、超氧化物歧化酶（SOD）及碱性磷酸酶（AKP）活性的影响,实验持续60d．实验设置了5个盐度梯度（盐度5、10、15、20、25）和对照组（盐度0）,每梯度设3个平行组,各组盐度和pH值保持一致．日本鳗鲡血清中免疫酶活力指标：碱性磷酸酶、溶茵酶、超氧化物歧化酶在实验的第7天和第14天测定．实验结果表明,盐度5组相对增重率最高（279．78％±28．37％）,其次是盐度10组（278．74％±22．25％）,盐度15、20、25组相对增重率分别为234．39％±21．28％、230．28％±26．31％、228．01％±29．29％．对照组相对增重率为233．20％-4-25．18％,盐度5和10组与对照组差异显著（P〈0．05）,其余各组与对照组差异不显著．第7天和第14天,盐度10组碱性磷酸酶活性最高,分别为225．05U／dm。和251．11U／dm’,其次是盐度5组,分别为221．76U／dm。和236．01U／dm。,显著高于对照组（P〈0．05）．第7天和第14天盐度20、25组溶菌酶活性显著高于对照组（P〈0．01）．超氧化物歧化酶随着盐度的升高呈逐步上升趋势．第14天,盐度20、25纽溶菌酶活性仍保持较高水平,SOD回落至对照组水平,而各组AKP较第7天略有上升．  相似文献