论西藏扎达上白垩统波林夏拉组

上白垩统波林夏拉组的命名地点位于西藏西南部扎达波林,是一套以泥灰岩及灰岩为主的地层,底部以含海绿石灰岩与下伏下白垩统嘎姐组含海绿石石英砂岩整合接触,未见顶。波林夏拉组的时代据其所含丰富浮游有孔虫可被确定为晚白垩世Albian晚期至Maastrichtian晚期,其所含化石组合可以与晚白垩世特提斯喜马拉雅从台地到盆地的同...     

南黄海北部晚第四纪底栖有孔虫群落 分布特征及对古冷水团的指示

底栖有孔虫和粒度分析结果表明,南黄海北部DLC70 3孔（36°38′15″ N,123°32′56″ E,水深7200 m）7120 m长的柱状样保存了130 ka以来的沉积记录。依据349个样品的底栖有孔虫丰度和特征种的分布,结合岩性粒度变化,可识别9个底栖有孔虫组合,对应5个海相层和4个陆相至过渡相层;结合AMS14C和OSL测年数据建立了钻孔晚更新世以来的年代地层,可以与南黄海其他钻孔的地层进行对比。应用属种组合和不同生态种的丰度变化,探讨了研究区末次间冰期以来的古环境变化,认为海平面频繁波动是该地区不同成因类型地层从陆相、潮间、滨岸、滨海、近岸浅海、到浅海反复演替的关键。孔段2040~2780 m（MIS3早期）和5500~7120 m（MIS5e）的底栖有孔虫优势种是 Buccella frigida和Protelphidium tuberculatum,代表了与目前相似的冷涡边缘的冷水环境,指示南黄海古冷水团在MIS5e和MIS3早期高海平面时期已经存在。     

Cenomanian-Coniacian Sea-level Change and Dissolved Oxygen Fluctuations in Tethys-Himalaya: Evidences from Benthic Foraminifera of Gamba, Tibet

Benthic foraminifera, preserved in the Late Cretaceous organic carbon-rich sediments of Gamba, southern Tibet, provide high-resolution proxies for sea-level changes and dissolved oxygen fluctuations of southeastern Tethys. The fossils were statistically analyzed and divided into three faunas of "Cenomanian fauna", "Turonian fauna", and "Coniacian fauna". A middle neritic-upper bathal environment (50-250m) was estimated considering the ratios of planktonic and epifaunal benthic foraminifera (P/(P+E)), the morphological analysis according to the studies of recent foraminifera and the abundant distributions of depth-related species such as Alabamina creta, Laevidentalina sp., Praebulimina spp., Pleurostomella cf. naranjoensis, Pyrulina sp., Quinqueloculina spp., Haplophragmoides spp., etc. The result shows an almost parallel trend with the global transgressive and regressive cycles, but the former fluctuates more frequently at upper Cenomanian, which probably indicates tectonic instability of the continental margin. According to the benthic foraminiferal richness (BFN), Shannon-Weiner diversity (H(s)), as well as benthic foraminiferal oxygen index (BFOI), five periods of oxygen depleted conditions (dysoxic-anoxic) have been recognized. They correspond to the OAE2, the lower Turonian, the upper Turonian, the Turonian-Caniacian boundary event and the probably OAE3. In addition, the oxygen fluctuations in Gamba might be controlled directly by sea-level changes, while the paleoproductivity and oxygen conditions interacted with each other under oxygen deficiency environments.     

Benthic foraminifera as bio-indicators of trace element pollution in the heavily contaminated Santa Gilla lagoon (Cagliari, Italy)

In order to assess the response of benthic foraminifera to trace element pollution, a study of benthic foraminiferal assemblages was carried out into sediment samples collected from the Santa Gilla lagoon (Sardinia, Italy). The lagoon has been contaminated by industrial waste, mainly trace elements, as well as by agricultural and domestic effluent. The analysis of surficial sediment shows enrichment in trace elements, including Cr, Cu, Hg, Ni, Pb and Zn. Biotic and abiotic data, analyzed with multivariate techniques of statistical analysis, reveal a distinct separation of both the highly polluted and less polluted sampling sites. The innermost part of the lagoon, comprising the industrial complex at Macchiareddu, is exposed to a high load of trace elements which are probably enhanced by their accumulation in the finer sediment fraction. This area reveals lower diversity and higher percentages of abnormalities when compared to the outermost part of the lagoon.     

Vertical distribution of living mangrove foraminifera from KwaZulu-Natal,South Africa

Modern foraminiferal assemblage zones can be used to reconstruct palaeo sea levels when applied to fossil foraminifera down a sediment core. Previous intertidal foraminiferal studies have predominantly focused on assemblages in surface sediments (0–1 cm), with the rationale that surface assemblages reflect the modern-day environment. Foraminifera live infaunally and therefore there is a need to document the infaunal vertical distribution of living foraminifera to fully capture the modern environment. Infaunal foraminiferal populations may compositionally differ from or be similar to those in the uppermost 1 cm of a core sample, but abundance is variable vertically, making it very complex to reconstruct and interpret past sea levels. This can have implications for the choice of assemblages to use as modern analogues for past sea-level reconstructions. This study documents the vertical infaunal distribution of living foraminifera, to allow for more informed interpretations of palaeo-reconstructions in mangrove environments. The down-core vertical distribution and abundance of living foraminifera, along with grain size and organic content, were documented using sediment cores along an elevational transect. Nine taxa were recorded as living at the time of collection, six of which were restricted to the top 4 cm. The majority of these were calcareous and found in the cores situated closer to the intertidal channel. Therefore, we argue that the diversity of living calcareous and agglutinated foraminifera could be restricted by grain size, with coarser grain sizes associated with lower species diversity. The findings suggest that foraminiferal species inhabiting the top 4 cm represent deeper living foraminiferal populations. Therefore, the top 4-cm interval can be used to establish a modern training set upon which reconstructions can be based. The findings from this study will provide guidance on the use of South African mangrove environments for future sea-level reconstructions.     

Cantabriconus reocinianus n. gen., n. sp. a new conical agglutinating benthic foraminifera from the upper Aptian-lower Albian of Cantabria,N-Spain

A new large conical agglutinating benthic foraminifer is described as Cantabriconus reocinianus n. gen., n. sp. from the upper Aptian-lower Albian Urgonian limestones of the Basque-Cantabrian Basin. It is characterized by a prominent initial trochospire, an undivided marginal zone, an endoskeleton of massive, vertically aligned, and often fused pillars, as well as a thick, most likely pseudo-keriothecal wall structure. Due to the generic characteristics, the new taxon is assigned to the Coskinolinidae. Cantabriconus n. gen. is compared with the Cretaceous Pseudolituonella Marie, and the early Paleogene taxa Coskinolina Stache and Coskinon Hottinger & Drobne as well as the Middle Jurassic Conicopfenderina Septfontaine. Cantabriconus reocinianus n. gen., n. sp. has been observed in the upper Aptian Reocín Formation and in the lower part of the Albian Ramales and Meruelo Formations to the east of Santander. It might therefore be considered an index taxon for Urgonian-type limestones of the Basque-Cantabrian Basin in this time interval.     

Linkage of deep sea rapid acidification process and extinction of benthic foraminifera in the deep sea at the Paleocene/Eocene transition

Ocean Drilling Program Leg 199 Site 1220 provides a continuous sedimentary section across the Paleocene/Eocene (P/E) transition in the carbonate‐bearing sediments on 56–57 Ma oceanic crust. The large negative δ¹³C shift in seawater is likely due to the disintegration of methane hydrate, which is expected to be rapidly changed to carbon dioxide in the atmosphere and well‐oxygenated seawater, leading to a reduction in deep‐sea pH. A pH decrease was very likely responsible for the emergence of agglutinated foraminiferal fauna as calcareous fauna was eliminated by acidification at the P/E transition at Site 1220. The absence of the more resistant calcareous benthic foraminifera and the presence of the planktonic foraminifera at Site 1220 is interesting and unique, which indicates that calcareous benthic foraminifera suffered greatly from living on the seafloor. Box model calculation demonstrates that, assuming the same mean alkalinity as today, pCO₂ must increase from 280 ppm to about 410 ppm for the calcite undersaturation in the deep ocean and for the oversaturation in the surface ocean during the P/E transition. The calculated increased pCO₂ coincides with paleo‐botanical evidence. The current global emission rate (～7.3 peta (10¹⁵) gC/y) of anthropogenic carbon input is approximately 30 times of the estimate at the P/E transition. The results at the P/E transition give an implication that the deep sea benthic fauna will be threatened in future in combination with ocean acidification, increased sea surface temperature and more stratified surface water.     

南海北部秋季活体浮游有孔虫的组成与分布

对2004年9月采自南海北部海区19个站位40个垂直浮游拖网样品中的活体浮游有孔虫进行了定量分析, 探讨了该区秋季现代有孔虫的组成、分布及其影响因素.研究表明, 该区秋季现代浮游有孔虫以热带暖水群落为主, 呈现出明显的区域变化.浮游有孔虫的丰度主要呈西北高、东南低的分布格局.浅层水种G. sacculifer和G. ruber的高含量主要出现在近岸带; N. dutertrei的高含量主要出现在外陆架和陆坡区域; G. menardii的高含量主要出现在深水区域; G. calida和G. aequilateralis两水种的含量分布有明显的相似性, 主要出现在深水区, 在越南岸外站位其含量远高出区域其他站位.研究认为, 南海北部秋季水体浮游有孔虫的分布主要受初级生产力和水深的共同制约, 高初级生产力水平下浮游有孔虫的丰度明显要高, 水深则对中深层水种G. menardii、G. calida和G. aequilateralis的分布有明显的制约作用.南海北部秋季温跃层的温盐结构对中层水种N. dutertrei、G. glutinata、G. calida和G. aequilateralis的分布有一定的影响.此外, 暖涡水体对浮游有孔虫的丰度和组成也有明显影响, 位于暖涡中心区的浮游有孔虫丰度明显增高, 特征属种G. sacculifer的含量明显高出周边站位.P. obliquiloculata的高含量主要出现在东北部黑潮分支影响区.      

Heavy metals in the benthic foraminifera from the coastal lagoons,Red Sea,Egypt: indicators of anthropogenic impact on environment (case study)

Concentrations of Fe, Mn, Zn, Cu, Pb, Ni, and Cd were measured in several species and genera of Recent benthic foraminifera from three coastal lagoons, namely Abu-Shaar, Umm al-Huwaytat, and Marsa Shuni lagoons located along the Egyptian Red Sea coast. Spatially significant differences in the metal concentrations of benthic foraminifera were recorded among different sites. However, some foraminiferal species display deformation in their coiling, general shape of chambers and the apertures. Abu-Shaar and Umm al-Huwaytat lagoons are virtually influenced by anthropogenic activities while Marsa Shuni lagoon is affected by natural inputs. Benthic foraminifer shows high concentrations of Fe and Mn, especially in Umm al-Huwaytat lagoon. Foraminiferal black tests support this result and reflect selectivity for iron absorption. Among the metals analyzed, Cd, Pb, and Cu showed significant high concentrations in benthic foraminifera at the study areas. The anthropogenic activities and natural inputs are responsible for the abnormalities in benthic foraminifera. Therefore, benthic foraminifera can be used as a good indicator of the environmental changes.