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1.
HUXiu-mian Sv&#;benick&#;LILIAN SartiMASSIMO 《地学前缘》2005,12(2):38-44
Río
Fardes剖面位于西班牙南部Granada东北,构造上属于深水环境的Subbetic中带.该剖面主要由白垩纪Fardes组第Ⅱ段和第Ⅲ段(半)远洋沉积构成,并出现浊流沉积和混杂沉积.本次研究在Fardes组浊流层序内首次发现两段红色沉积.钙质超微化石表明红层的时间从Turonian早期
(UC7带)到Coniacian中期-晚期界线 (UC10/?UC11带).红层由mm级红色泥岩夹灰色、杂色、偶尔黑色泥岩和钙质泥岩组成.沉积学研究表明新发现的Turonian-Coniacian远洋红色泥岩沉积形成于CCD面之下深水盆地环境,浊流和碎屑流沉积强烈地影响着(半)远洋环境的背景泥岩相,并成为红色沉积结束的原因. 相似文献
2.
Río Fardes剖面位于西班牙南部Granada东北,构造上属于深水环境的Subbetic中带。该剖面主要由白垩纪Fardes组第Ⅱ段和第Ⅲ段(半)远洋沉积构成,并出现浊流沉积和混杂沉积。本次研究在Fardes组浊流层序内首次发现两段红色沉积。钙质超微化石表明红层的时间从Turonian早期(UC7 带)到Coniacian中期—晚期界线(UC10/?UC11带)。红层由mm级红色泥岩夹灰色、杂色、偶尔黑色泥岩和钙质泥岩组成。沉积学研究表明新发现的Turonian Coniacian远洋红色泥岩沉积形成于CCD面之下深水盆地环境,浊流和碎屑流沉积强烈地影响着(半)远洋环境的背景泥岩相,并成为红色沉积结束的原因。 相似文献
3.
桂西南柳桥地区深水相二叠系-三叠系界线剖面 总被引：9，自引：1，他引：8
桂西南柳桥地区上二叠统为厚约84m的浅灰—灰白色块状海绵蓝藻生物灰岩(生物礁),之上为浅灰绿色—暗灰色薄层状含远洋浮游生物硅质岩、含泥质硅质岩、硅质泥岩(大隆组),这套深水相的沉积岩夹有大量浅灰白色的粘土岩。上覆的三叠系罗楼组底部为黄色泥岩,夹多层灰白色粘土岩,往上渐变为灰色薄层状含大量双壳类、菊石化石的钙质泥岩、泥灰岩。柳桥地区晚二叠世末期沉积岩和中基性火山岩的特征显示其是在地壳裂解、快速沉降、相对海平面快速上升过程中迅速淹没台地边缘的生物礁而形成的深水相海盆,造成深水盆地与浅水台地并存,具有多岛洋的地理分布格局。东攀二叠系-三叠系界线剖面的露头完整,对剖面的岩石学特征、生物化石组合特征等方面的详细研究显示,该地区一直处于连续沉积的深水环境中,没有发生沉积间断,界线上下的岩石特征和生物组合特征较清楚。 相似文献
4.
《地层学杂志》2022,(1)
本研究采用碳酸盐岩微相分析的方法,对位于扬子板块西缘云南镇雄栖霞组—茅口组碳酸盐岩的生物组合、微相类型和岩相古地理进行了研究,将剖面碳酸盐岩归纳为24个微相:小有孔虫-假蠕孔藻生物碎屑粒泥岩、海绵骨针粒泥岩、生物碎屑密集堆积的泥粒岩、苔藓虫生物碎屑泥粒岩、发育孔隙的棘皮颗粒岩、粗枝藻-小有孔虫泥粒岩、似球粒内碎屑生物碎屑颗粒岩、二叠钙藻粒泥岩、含生物碎屑细晶白云岩、小有孔虫泥状灰岩、二叠钙藻生物碎屑泥粒岩、二叠钙藻-古串珠虫-苔藓虫泥粒岩、古串珠虫生物碎屑颗粒岩、细粒生物碎屑粒泥岩、生物扰动细粒生物碎屑粒泥岩、海绵骨针粒泥岩、叶状藻障积岩、包壳颗粒翁格达藻颗粒岩、翁格达藻-?颗粒岩、冲洗差的生物碎屑粒泥岩、棘皮-苔藓虫泥粒岩、小有孔虫-钙藻生物碎屑泥粒岩、裸海松藻生物碎屑泥粒岩、似球粒颗粒岩。剖面垂向微相特征指示其时代为亚丁斯克期末期—空谷期,栖霞组形成于碳酸盐缓坡环境,以假蠕孔藻组合为特征。栖霞组顶部为白云岩,为区域性不整合面,该不整合面标志着扬子板块碳酸盐缓坡被填平,形成较为平缓的台地地形。瓜德鲁普世早期,随着相对海平面升高,上扬子区域为较深水所覆盖,形成非镶边碳酸盐台地环境,以二叠钙藻组合为特征;随着扬子板块南侧台地边缘礁的形成,瓜德鲁普世中晚期转变为镶边碳酸盐台地环境,以翁格达藻组合为特征。 相似文献
5.
阿尔卑斯-喀尔巴阡上白垩统大洋红层特征与对比 总被引：2，自引：0，他引：2
在前人研究的基础上,从时代、岩性、古生物、沉积速率、沉积环境等方面对阿尔卑斯—喀尔巴阡地区的上白垩统大洋红层进行了详细对比,发现研究区内上白垩统大洋红层最早出露于Cenomanian期,最晚可延续至古近纪,且在Campanian期出露最为广泛,其岩性以灰岩、泥灰岩和含泥灰岩为主,生物化石以浮游有孔虫为主,沉积速率较低且在各地不尽相似,在CCD面上、下均可以出现,沉积环境一般是大陆边缘盆地、斜坡和大洋盆地等远洋、半远洋环境。通过比较分析,为进一步深入研究上白垩统大洋红层提供较为全面的基础资料。 相似文献
6.
赣西南寒武纪—奥陶纪深水沉积 总被引：1，自引：0，他引：1
赣西南地区的寒武系－奥陶系主要由深水环境沉积组成，可以识别出５个相类型：砂岩相，砂岩－泥岩相，粉砂岩－泥岩相，泥（板）岩相和硅岩组。它们属于浊流沉积和远洋－半远洋沉积，按相的分布，可以分出３个相组合，分别形成于中扇环境，外扇环境和深海平原环境，地层层序中的３组垂向旋回分别由海平面升降变化、盆地沉降和海底扇进积作用因素所控制。砂岩的化学成分反映基大地构造背景为被动大陆边缘。 相似文献
7.
Luba JANSA 《地学前缘》2005,12(2):151-161
深海钻探揭示构成环礁的浅水碳酸盐建隆覆盖沉积在太平洋西北部平顶海山之上。相对于现今珊瑚藻类生物构成的环礁而言,白垩纪和古新世孤立的环礁的四周边缘生物含量甚少,造礁能力下降。这些环礁浅水碳酸盐沉积在火山基座的顶部,在Albian初期、Albian末期、Maastrichtian晚期和始新世中期发生沉没。早期研究认为这些碳酸盐体系经历了地面暴露阶段以及随后的海侵淹没阶段。然而,一个事实是,环礁沉没仅发生在当太平洋板块背负着平顶海山向北漂移过程中,并且是经过南纬7°以后。几个不同的假说用来解释该时期环礁沉没现象,包括环礁暴露、喀斯特化、地面侵蚀、增强赤道上升洋流、缺氧和/或者富营养的浑浊水的出现等。文中在太平洋平顶海山深海钻孔的沉积、生物地层和古纬度数据综合研究基础上,提出一种新模式用于解释晚白垩世—古新世浅水碳酸盐建造的沉没。与以前的模式不同的是,文中提出,这些晚白垩世—古新世“环礁”之所以发生沉没,原因是受到原始环南赤道洋流(pSEC)的影响,导致一种对分泌碳酸盐的生物不利环境的产生。而且,当这些平顶海山漂移到南纬5°时,即赤道古纬度带,许多浅水碳酸盐建造之上,铁锰结核开始沉积。同时,平顶海山下沉到溶解氧极小层(海平面之下400~1 100 m)和原始环南赤道中层洋流( pEI 相似文献
8.
通过对东经90°海岭ODP758钻孔岩心3.5Ma以来的浮游有孔虫远洋记录的研究,结合岩性地层、稳定同位素地层、碳酸盐地层等资料,探讨了喜马拉雅山加速隆升、"中更新世气候转型"、"中布容溶解"事件等重大构造、环境事件在研究区的表现及相关机制。通过对各项指标的分析和对比,根据ODP758岩心的有孔虫组合面貌、古温度、古盐度和古温跃层的变化情况,推断研究区在1.4～0.7Ma期间的气候变化可能是在"中更新世气候转型"条件下发生的。碳酸钙、碳酸钙沉积通量和非碳酸钙沉积通量曲线在1.7Ma时快速增长,与现有资料显示的青藏高原的隆升历史相符,分别与青藏高原隆升过程中的青藏运动A幕、B幕、C幕(1.7Ma)和昆仑-黄河运动(1.2～0.6Ma)相当。碳酸钙含量、大于150μm的粗组分含量、浮游有孔虫沉积通量和浮游有孔虫生物地层揭示出在0.5～0.4Ma期间研究区深海碳酸盐遭受了强烈溶解。此事件与大西洋、太平洋、印度洋及南沙海区沉积记录中的"中布容溶解"事件一致。 相似文献
9.
10.
曹忻耕 《四川地质科技情报》1994,(1):13-17
康滇地轴东缘的砂岩型铜矿，集中产于会理和米市两个红色盆地内。这两个红色盆地，据研究是二叠纪玄武岩喷溢后经地壳均衡调整后的陆内断陷盆地。其内沉积了一套巨厚的侏罗纪、白垩纪红色岩系．构成由砂砾岩-砂岩-泥岩-泥灰岩-石膏的多旋回沉积组合，为河流相、河流三角洲相、河湖交替相的沉积环境。 相似文献
11.
The upper Campanian to upper Maastrichtian sedimentary sequence of the Kiseiba Formation in south Western Desert is sampled and described in two surface sections (Sinn El Kaddab and Wadi Abu Siyal). Forty-four agglutinated foraminiferal species are identified from 42 samples in the studied succession. The benthic foraminiferal assemblages are dominated by agglutinated foraminifera which comprise more than 90% of the assemblage. The agglutinated foraminifera are subdivided into five morphogroups (A, B, C, D, E) according to shell architecture, integrated with the supposed microhabitat and feeding strategy. The foraminiferal assemblage is assigned to mixohaline shallow water environments. These assemblages with Ammoastuta megacribrostomoides and Ammotium bartheli suggest lagoonal environments with considerably reduced salinity in warm climates and high runoff for the late Campanian-Maastrichtian interval. 相似文献
12.
Claudia G. Cetean Ramona B?lcMichael A. Kaminski Sorin Filipescu 《Cretaceous Research》2011,32(5):575-590
Study of an upper Santonian to upper Campanian hemipelagic succession from the southern part of the Romanian Eastern Carpathians enables us to establish an integrated biostratigraphy based on planktonic foraminifera and calcareous nannofossils and to compare this record with the agglutinated foraminiferal biozonation used for the Carpathians.Benthic foraminiferal assemblages were investigated using several methods, such as agglutinated and calcareous benthic foraminiferal morphogroups, and the benthic foraminiferal oxygen index in order to determine their response to environmental parameters in the basin (correlated with sea-level maxima documented by regional sea-level curves for the Tethys). A pattern of changes in benthic foraminiferal communities associated with increased organic carbon flux and rising sea-levels can be summarized as follows in the studied succession. As sea-level begins to rise there is an increase in the proportion of calcareous benthic foraminifera at the expense of agglutinated foraminifera within the benthic assemblages (earliest Campanian, mid-late Campanian). Once sea-level rises, an increase in the elongate keeled morphotype of agglutinated foraminifera (shallower water forms) can be observed, and if sea-level remains high for an extended period (as in the early Campanian) then an invasion of both agglutinated and benthic calcareous foraminifera characteristic of outer shelf-upper slope environments take place in the basin. The variations in tubular and deep infaunal morphotypes of agglutinated foraminifera are ascribed to varying levels of organic carbon flux. 相似文献
13.
深海研究中的底栖有孔虫：回顾与展望 总被引：4，自引：0，他引：4
底栖有孔虫在古环境研究中的应用先是用作古水深或水团的标志物。随着新技术的应用,识别出了2种不同的底栖有孔虫微生境：外生种和内生种;认识到甚至深海底栖有孔虫,也能对表层浮游生物勃发的季节性短暂事件作出响应,因为沉降到海底的有机物质供养着底栖有孔虫。目前,底栖有孔虫被广泛应用于估算海洋表层生产力和底层水团的含氧量。回顾了深海底栖有孔虫生态研究的历史和其在古海洋学中的应用,并强调研究、应用中的新方法、新技术。中国已经加入了诸如IODP等深海研究计划,有必要向我国学术界提供底栖有孔虫研究的新方向,以资参考。 相似文献
14.
Oceanic crust production and climate during the last 100 Myr 总被引：2，自引：0，他引：2
In order to evaluate the possible influence of oceanic crust production on climatic changes during the past 100Myr variations in total oceanic crust for this period including production at mid-ocean ridges, oceanic plateaus, and back-arc basins were calculated using the most recent and accurate time-scales. The rates presented here differ from those of Larson (1991a, b) on Cenozoic fluctuations and show that (1) maximum production values occurred during the Cenomanian, Palaeocene, and late Oligocene-early Miocene and (2) minimum values occurred in Campanian-Maastrichtian, late Eocene, and middle Miocene. Significantly, variations of oceanic crust production correspond with variations in the δ18 O of deep-water benthic foraminifera: maximum values of oceanic crust production correspond with minimum values of δ18 O, and minimum production values with maximum values of δ18 O. This latter synchronism suggests that changes in land-sea relationships and atmospheric CO2 related to major fluctuations in oceanic crust production were the main cause of mid-Cretaceous warming and Late Cretaceous cooling, and of climatic quasi-cycles having a periodicity of 33–38 million years over the last 100 Myr. This is the first report showing variations of ocean crust production synchronized with the Cenozoic climate changes. 相似文献
15.
The Late Cretaceous (Maastrichtian) to early Paleocene (Thanetian) shallow water (<100 m) agglutinated foraminifera from a section at Dakhla Oasis (Western Desert, Egypt) were analyzed for their assemblage, species and genera distribution, diversity, depositional environment, community structure and palaeobathymetry with respect to regional tectonics, climate and global eustasy. Data suggest an equitable benthic environment with low species dominance deposited in a brackish littoral and/or marsh setting. Sea level curves using characteristic benthic foraminiferal species, genera and assemblages corroborate quantitatively generated estimate and statistical analysis. Data suggests that in the absence of or of an impoverished benthic foraminiferal fauna, a high resolution agglutinated foraminiferal dataset can be as good a predictor of the benthic community structure and environment, as its calcareous counterpart, at least for shallow settings (<100 m). Present data also provides a good window in better understanding the distribution and interrelationship between the three dominant genera, Haplophragmoides, Trochammina and Ammobaculites. Faunal changes at boundaries (Cretaceous/Paleogene, Danian/Selandian and Selandian/Thanetian) are also evaluated. 相似文献
16.
《Proceedings of the Geologists' Association. Geologists' Association》2022,133(3):197-211
We carried out a comprehensive facies/microfacies, micropalaeontological and biostratigraphical analysis of several carbonate olistoliths incorporated within a widely developed Albian conglomeratic sequence from the Eastern Carpathians of Romania. The majority of the sampled olistoliths contain a rich assemblage of benthic foraminifera and calcareous green algae. All of the described microfossils represent common lowermost Cretaceous taxa not previously reported from these carbonate elements or from this region. Based on benthic foraminifera assemblages the age of the studied olistoliths is upper Berriasian–lower Valanginian, contrary to the general belief that they are Barremian–Aptian in age. The dominant microfacies types mainly reflect deposition in shallow-water environments and show similarities with synchronous platform carbonates of the central-western Neotethys Ocean. The micropalaeontological and sedimentological data support new interpretations concerning the source area of these carbonate elements and provide new information concerning the evolution of the lowermost Cretaceous carbonate platforms of the Carpathians. 相似文献
17.
Yuvaraja Arumugm Anil K Gupta Mruganka K Panigrahi 《Journal of Earth System Science》2014,123(7):1671-1680
Deep-sea benthic foraminifera are an important and widely used marine proxy to understand paleoceanographic and paleoclimatic changes on regional and global scales, owing to their sensitivity to oceanic and climatic turnovers. Some species of benthic foraminifera are sensitive to changes in water mass properties whereas others are sensitive to organic fluxes and deep-sea oxygenation. Benthic faunal diversity has been found closely linked to food web, bottom water oxygen levels, and substrate and water mass stability. The present study is aimed at analyzing species diversity trends in benthic foraminifera and their linkages with Indian monsoon variability during the Neogene. Species diversity of benthic foraminifera is examined in terms of number of species (S), information function (H), equitability (E) and Sanders’ rarefied values, which were combined with relative abundances of high and low productivity benthic foraminifera at Ocean Drilling Program Hole 730A, Oman margin, western Arabian Sea. The Oman margin offers the best opportunity to understand monsoon-driven changes in benthic diversity since summer monsoon winds have greater impact on the study area. The species diversity was higher during the early Miocene Climatic Optimum (～17.2–16.4 Ma) followed by a decrease during 16.4–13 Ma coinciding with a major increase in Antarctic ice volume and increased formation of Antarctic Bottom Water. All the diversity parameters show an increase during 13–11.6 Ma, a gradual decrease during 11.6–9 Ma and then an increase with a maximum at 7 Ma. Thereafter the values show little change until 1.2 Ma when all the parameters abruptly decrease. The benthic foraminiferal populations and diversity at Hole 730A were mainly driven by the Indian monsoon, and polar waters might have played a minor or no role since early Neogene period as the Arabian Sea is an enclosed basin. 相似文献
18.
The Paleocene/Eocene boundary intervals were studied in three outcrops along the Nile Valley: Gabal Taramsa, Gabal Qreiya, and Gabal Nag El Quda in Qena and Esna regions. The planktonic and benthic foraminifera have been examined. The qualitative study of planktonic foraminifera distinguishes eight planktonic biozones from (P4 and P5) Paleocene age to (E1, E2, E3, E4, E5, and E6) Early Eocene age. The analysis of quantitative distribution patterns of benthic foraminifera allows the reconstruction of the paleoenvironmental settings in the studied area. The disappearance or scarce appearance of deeper-water benthic foraminifera (Angulogavelinella avnimelechi and Gavelinella rubiginosus) and increasing dominance of shallow-marine taxa (Buliminides, Loxostomoides applinae) indicate deposition in shallow water environments. The benthic foraminiferal assemblages which dominated by Loxostomoides applinae, Buliminids, and Lenticulina indicate Dysoxic conditions and maximum food levels. The species of mid-way type fauna dominate the assemblages of the studied area; the species of Velasco-type fauna are very rare. 相似文献
19.
Distribution of belemnites and benthic foraminifers in the Campanian-Maastrichtian boundary layers of the Aktulagai section, one of Upper Cretaceous reference sections in the east of the European paleobiogeographic region (EPR) is discussed. The base of Lanceolata Beds defined by A.D. Arkhangelsky in 1912 is well-substantiated biostratigraphic level corresponding to boundary between the Campanian and Maastrichtian stages. In spacious outcrops of Upper Cretaceous deposits in the Aktulagai Plateau (Aktyubinsk region, Kazakhstan Republic), “primitive Belemnella forms” (two rostra plates) appearing above that base distinctly replace the genus Belemnitella dominant in the Campanian. Seven successive zonal assemblages of benthic foraminifers (one plate) are established in the boundary interval. The Aktulagai reference section of Upper Cretaceous sediments can be used to trace the Campanian-Maastrichtian boundary from the eastern EPR to Boreal regions of Russia based on abundant micro-and nannofossils. 相似文献
20.
Benthic foraminifera are one of the most commonly used indicators to infer paleodepth. The information on depth distribution of fossil benthic foraminifera is generally obtained from normal marine environments. However, a significant gap exists with respect to implications of benthic foraminiferal distributions in unique sedimentary successions, such as those deposited under upwelling regimes. In such settings, the paleobathymetric signal is somewhat obscured by the extreme food fluxes and oxygen depletion at the seafloor that cause changes in benthic foraminiferal assemblage composition. Nevertheless, the dynamics of upwelling systems, and as a result the sediment and organic matter accumulation, are known to be directly influenced by eustatic changes, making paleobathymetric reconstruction highly valuable for understanding these systems.The Upper Cretaceous high productivity marine succession of southern Israel, with its variable lithologies, provides a unique opportunity for addressing this issue. Through this succession, a significant turnover in the benthic foraminiferal assemblages is observed associated with a sharp change in lithology from phosphate (Phosphate Member) to organic rich carbonates (Oil Shale Member; OSM). Statistical nMDS analysis distinguished four groups of species indicative of distinct depth habitats: <200 m, 100–300 m, 300–500 m, and >500 m. Each one of these groups corresponds to different parts of the sequence. According to our analysis, the shift in the benthic foraminiferal assemblages is attributed to a distinct regional deepening from shelf environment (<200 m) in the Phosphate Member (upper Campanian) to upper bathyal (200–500 m) at the base of OSM (base Maastrichtian), and deeper to middle bathyal (>500 m) during the Maastrichtian. While taking into account other factors affecting benthic foraminiferal distribution, this study demonstrates that depth distribution models based on normal marine settings might also be applicable as proxies for paleobathymetry in high productivity environments. 相似文献