珠江口黄茅海河口湾表层沉积物中有孔虫和介形虫的分布及其影响因素^*          下载免费PDF全文

吴洁  刘春莲  贾良文  杨婷婷  张素青  殷鉴 《古地理学报》2013,15(3):413-422

珠江口黄茅海河口湾的表层沉积物100个站位样品中共发现有孔虫21属36种、介形虫16属20种。优势种组合分别为Ammonia beccarii-Quinqueloculina akneriana rotunda-Cavarotalia annectens-Elphidium advenum和Neomonoceratina delicata-Sinocytheridea impressa-Bicornucythere bisanensis。有孔虫及介形虫的丰度和分异度均表现出“北低南高”,即口门低、向海高的特点。样品中有孔虫和介形虫属种的去趋势对应分析（DCA）表明,盐度是影响该区有孔虫和介形虫分布的最重要因素,其次是水动力条件,水深对有孔虫和介形虫的分布也有一定影响,但并非主要控制性因素。由于受径流影响较大,河口湾北部的水体盐度较低、径流动力较强,不利于有孔虫和介形虫的生存,导致其丰度及分异度均较低。河口湾南部水体盐度升高,潮流动力较强,同时受众多岛屿屏障作用,环境较为稳定,有孔虫和介形虫的丰度和分异度均迅速上升。  相似文献   

第四纪湖相介形类壳体化石在古环境中的应用——种属组合研究进展与问题     

张家武  何晶  陈硕  李双 《地球科学进展》2009,24(11)

综述了第四纪湖相介形虫化石种属组合在环境重建研究中取得的进展和存在问题,讨论了今后发展的趋势.湖泊沉积物介形类种属组合正逐渐成为古环境重建研究的常规微体生物学指标,过去几十年来国际国内研究取得重要进展,种属组合与环境参数的定量化研究成为主要趋势.化石壳体样品处理、埋藏条件评价等是提取种属组合指标的重要影响因素,需要规范化.现生种的个体与群落生态信息定量观测、调查研究是利用现代类比法(MAT)定量重建古环境的基础,也是我国介形类化石组合与环境重建中应该加强的方面.  相似文献   

Climatic change recorded by stable isotopes and trace elements in a British Holocene tufa   总被引：1，自引：0，他引：1  

E. R. Garnett  J. E. Andrews  R. C. Preece  P. F. Dennis 《第四纪科学杂志》2004,19(3):251-262

Combined stable isotope (δ¹⁸O and δ¹³C) and trace element (Mg, Sr) geochemistry from bulk tufa calcite and ostracod shell calcite from an early Holocene British tufa reveal clear records of Holocene palaeoclimatic change. Variation in δ¹⁸O is caused principally by change in the isotopic composition of Holocene rainfall (recharge), itself caused mainly by change in air temperature. The δ¹³C variability through much of the deposit reflects increasing influence of soil‐zone CO₂, owing to progressive woodland soil development. Bulk tufa Mg/Ca and Sr/Ca are controlled by their concentrations in the spring water. Importantly, Mg/Ca ratios are not related to δ¹⁸O values and thus show no temperature dependence. First‐order sympathetic relationships between δ¹³C values and Mg/Ca and Sr/Ca are controlled by aquifer processes (residence times, CO₂ degassing and calcite dissolution/reprecipitation) and probably record intensity of palaeorainfall (recharge) effects. Stable isotope records from ostracod shells show evidence of vital effects relative to bulk tufa data. The ostracod isotopic records are markedly ‘spiky’ because the ostracods record ‘snapshots’ of relatively short duration (years), whereas the bulk tufa samples record averages of longer time periods, probably decades. The δ¹⁸O record appears to show early Holocene warming, a thermal maximum at ca. 8900 cal. yr BP and the global 8200 yr BP cold event. Combined δ¹³C, Mg/Ca and Sr/Ca data suggest that early Holocene warming was accompanied by decreasing rainfall intensity. The Mg/Ca data suggest that the 8200 yr BP cold event was also dry. Warmer and wetter conditions were re‐established after the 8200 yr BP cold event until the top of the preserved tufa sequence at ca. 7100 cal. yr BP. Copyright © 2004 John Wiley & Sons, Ltd.  相似文献   

松辽盆地三肇地区扶余油层和杨大城子油层介形类古生态及沉积环境探讨   总被引：1，自引：0，他引：1       下载免费PDF全文

刘振文张智礼  王佰长张 铭 《中国地质》2006,33(5):1159-1166

笔者较系统地对松辽盆地三肇地区扶余油层和杨大城子油层(以下简称扶、杨油层)介形类的组合特征、分布范围以及古生态进行了研究。研究表明,扶、杨油层沉积时期的介形类自初期少量出现,之后发展并繁盛,末期全部绝灭。这种变化不仅表现为介形类动物群的属和种数有较大幅度的增加,而且其壳饰类型、分布范围与壳体保存状况也发生了规律性变化,但总体上仍为壳饰简单、属种类型较多、大小个体混生并生活于浅水湖泊环境的介形类群体。对介形类的埋葬环境与分布范围的分析表明,仅含有少量介形类化石碎片的杨五组、杨四组的沉积环境为冲积平原环境,而含有较丰富介形类化石的杨三组—扶上组的沉积环境则以浅湖环境为主,并自杨三组沉积时期在该区中部出现大范围的浅水湖泊后,随着时间的推移,湖泊分布范围与水深在缓慢的扩大或增加,至扶下组沉积时期该湖泊向西已扩大至大庆长垣以西,从而与齐家—古龙地区的湖泊连为一体,组成统一的松辽古湖泊。湖泊水体浅、气候干燥、氧化作用强,可能是造成该时期湖相砂、泥沉积物呈现红色的主要原因。  相似文献   

滇西北金沙江小中甸盆地晚更新世的介形类及其古环境          下载免费PDF全文

刘俊英  王海雷 《地质学报》2007,81(12):1652-1657,I0004

本文研究了滇西北地区金沙江小中甸盆地两条剖面(A和B)的介形类组合特征。据地层沉积特征和介形虫分布规律,结合光释光测年数据和野外调查研究,初步认为滇西北金沙江小中甸盆地存在倒数第二次冰期末期和末次冰期早冰阶的沉积,气候以冷湿为主,间以短暂的温干、冷干变化。  相似文献   

新疆乌鲁木齐地区上石炭亚系祁家沟组介形类及其古环境和古地理意义^*          下载免费PDF全文

靳军  罗正江  王剑  张晓刚  陈俊  李长根  孙语聪  黄兴  郄文昆  宋俊俊 《古地理学报》2023,25(2):356-367

新疆乌鲁木齐地区上石炭亚系祁家沟组地层出露较完整,沉积序列清晰,古生物化石丰富,但一直以来对祁家沟组的时代多有争论,且介形类研究薄弱。笔者在新疆乌鲁木齐地区祁家沟剖面上石炭亚系祁家沟组中鉴定出的介形类共计11属19种,并系统研究了这些介形类的组合面貌、地层分布,探讨了其古环境和古地理意义。结果表明: (1)根据介形类的组合面貌推断,祁家沟剖面祁家沟组的时代应为晚石炭亚纪莫斯科期—卡西莫夫期; (2)祁家沟组介形类生态类型属于古足目类和光滑速足目类的混合集群,符合构造活动区域的介形类OA1-OA3组合特征; (3)根据介形类的生态组合变化以及沉积学的证据,推断祁家沟剖面祁家沟组整体为滨、浅海沉积,存在海退序列; (4)祁家沟组介形类面貌与同时期的塔里木、准噶尔、中天山以及俄罗斯乌拉尔地区等产出的介形类最为相近,与北美、西欧和华北等板块的介形类也较为相似,表明晚石炭亚纪准噶尔、塔里木等块体聚集,并且距离劳俄大陆较近,所以其可与欧洲、北美板块的介形类进行属种交流。研究结果不仅进一步丰富了祁家沟组的化石材料,也对探索古亚洲洋演化特征和区域矿产开发具有重要的意义。  相似文献   

Annual variability of planktonic ostracods (Crustacea) in the South Adriatic Sea   总被引：1，自引：0，他引：1  

Igor Brautovi&#;  Natalia Bojani&#;  Mirna Batisti&#;  & Marina Cari&#; 《Marine Ecology》2006,27(2):124-132

Temporal variability and population structure of planktonic ostracods were investigated for the first time in the South Adriatic Sea during 1996. The maximal total ostracod abundance (1167 ind·100 m⁻³; 69% juveniles, 18% females and 13% males) was recorded in February. Thirteen species of marine planktonic ostracods were identified. Porroecia spinirostris and Archiconchoecia striata dominated the ostracod assemblage, accounting respectively for 62% and 18% of the total abundance. Their annual peaks were recorded during the cold season, which was the period of their intense reproduction, with favourable temperature conditions and lack of predators. The females surpassed the males in abundance in most species. The presence of the mesopelagic species indicated a strong influence of intermediate layer water masses from the Eastern Mediterranean Sea.  相似文献   

Late Pleistocene to Holocene paleoenvironmental changes in the NW Black Sea     

Andrei Briceag  Anastasia Yanchilina  William B. F. Ryan  Marius Stoica  Mihaela C. Melinte‐Dobrinescu 《第四纪科学杂志》2019,34(2):87-100

  相似文献   

松辽盆地东部宾县凹陷青山口组介形类生物地层与生态环境   总被引：1，自引：0，他引：1  

司伟民  席党鹏  万晓樵 《地质学报》2010,84(10):1389-1400

实测松辽盆地东部宾县地区鸟河畔的两条剖面。鸟河剖面上下岩性变化较小,以灰绿色泥岩、泥质粉砂岩为主,含数层黄铁矿薄层及介形虫灰岩薄层。红石山剖面岩性岩相变化较大,下部为灰绿色,黄绿色泥岩,上部出现大套红层。通过介形类组合特征,判断出这两个剖面属于青山口期沉积。其中,鸟河剖面对应青山口组一段上部,含介形类Triangulicypris torsuosus-Triangulicypris torsuosusvar.nota组合带。红石山剖面属于青山口组二段下部,含介形类Cypridea dekhoinensis-Li mnocyrpridea copiosa组合带;及叶肢介Nenestheria sp.、Cratostracus sp.、Dictyestheia sp.,化石富集成层。通过介形类古生态分析,松辽盆地宾东地区在青一段沉积时期为浅湖环境,湖水约为半咸水至微咸水。介形类的属种单调,但优势种Triangulicypris torsuosus极为繁盛。青二段沉积时期为滨浅湖环境,湖水盐度较青一段沉积时期降低,为淡水或微咸水。生物组成以腹足、轮藻、叶肢介以及带瘤介形类的出现为特征。宾县地区在青山口组沉积时期生物具有与松辽盆地其他地区相同的化石面貌和古生态特征。其一致性表明该时期宾县地区同属于松辽盆地。青一段至青二、三段之间微体化石古生态特征发生转变,暗示松辽盆地水体条件在该沉积阶段的演变。  相似文献   

CCA Inferred Environmental Implications of Common Ostracods on the Qinghai-Tibetan Plateau     

SONG Gao  WANG Hailei  ZHENG Mianping 《《地质学报》英文版》2015,89(2):585-597

103 surface sediment samples in 71 water bodies,such as lakes with different salinity,swamps,shallow puddles and rivers on the Qinghai-Tibetan Plateau(QTP),were collected to study the ecological distribution of living ostracods and their environmental implications. Total of 12 genus and 45 species living ostracods are identified. According to the frequencies and abundance of ostracods occurrence,Limnocythere dubiosa,Limnocytherellina kunlunensis,Ilyocypris bradyi,Candona candida,Eucypris rischtanica and Leucocythere dilatata are the common species on the QTP,with occurrence frequency of more than 8 and abundance of more than 570 in the 71 water bodies. Among them,L. dubiosa,occurring in 28 water bodies with 2177 shells,is the most widely distributed ostracod in this research. Canonical Correspondence Analysis(CCA) indicates high correlation between species and environmental variables,suggesting that the occurrence of species is strongly related to the changes in ecological conditions of habitats. Among eight environmental factors,salinity and p H value are the most affective variables that influence the species occurrence. L. kunlunensis is positively correlated with salinity while E. rischtanica is negatively correlated with salinity. C. candida has a positive correlation with salinity,as does I. bradyi although there is not such a strong correlation. L. dubiosa displays a positive correlation with p H value. Consequently,we discuss the environmental implications of the common living ostracods on the QTP based on the CCA as well as the distribution of ostracod species in different salinity and p H values water. L. dubiosa,L. kunlunensis and E. rischtanica are euryhaline species,among which,L. dubiosa is the most adaptable species on the QTP with large occurrence in sundry salinity water and the most widely adaptive range for p H values. L. kunlunensis prefers to saline water while E. rischtanica prefers to fresh water. Both L. kunlunensis and E. rischtanica can live in water from faintly acid to alkaline,in contrast,L. dubiosa only appears in neutral and alkaline water bodies. I. bradyi only occurs in fresh water and oligohaline water with a large p H tolerance range tolerance range from weakly acidic water to alkaline water weakly acidic water to alkaline water. C. Candida lives in freshwater,with p H value above eight. The six common species reach maximum abundance in alkaline water(p H 8-10) except for Ilyocypris bradyi.  相似文献