Journal of Micropalaeontology最新文献_第10页

Assessing the composition of fragmented agglutinated foraminiferal assemblages in ancient sediments: comparison of counting and area-based methods in Famennian samples (Late Devonian) 古沉积物中破碎凝集有孔虫组合的组成评估:法门纪(晚泥盆世)样品计数法与面积法的比较

IF 2 3区地球科学

Journal of Micropalaeontology Pub Date : 2018-01-05 DOI: 10.5194/JM-37-87-2018

C. Girard, A. Dufour, Anne‐Lise Charruault, S. Renaud

{"title":"Assessing the composition of fragmented agglutinated foraminiferal assemblages in ancient sediments: comparison of counting and area-based methods in Famennian samples (Late Devonian)","authors":"C. Girard, A. Dufour, Anne‐Lise Charruault, S. Renaud","doi":"10.5194/JM-37-87-2018","DOIUrl":"https://doi.org/10.5194/JM-37-87-2018","url":null,"abstract":"Abstract. Benthic foraminifera have been used as proxies for various paleoenvironmental variables such as food availability, carbon flux from surface waters, microhabitats, and indirectly water depth. Estimating assemblage composition based on morphotypes, as opposed to genus- or species-level identification, potentially loses important ecological information but opens the way to the study of ancient time periods. However, the ability to accurately constrain benthic foraminiferal assemblages has been questioned when the most abundant foraminifera are fragile agglutinated forms, particularly prone to fragmentation. Here we test an alternate method for accurately estimating the composition of fragmented assemblages. The cumulated area per morphotype method is assessed, i.e., the sum of the area of all tests or fragments of a given morphotype in a sample. The percentage of each morphotype is calculated as a portion of the total cumulated area. Percentages of different morphotypes based on counting and cumulated area methods are compared one by one and analyzed using principal component analyses, a co-inertia analysis, and Shannon diversity indices. Morphotype percentages are further compared to an estimate of water depth based on microfacies description. Percentages of the morphotypes are not related to water depth. In all cases, counting and cumulated area methods deliver highly similar results, suggesting that the less time-consuming traditional counting method may provide robust estimates of assemblages. The size of each morphotype may deliver paleobiological information, for instance regarding biomass, but should be considered carefully due to the pervasive issue of fragmentation.","PeriodicalId":54786,"journal":{"name":"Journal of Micropalaeontology","volume":"37 1","pages":"87-95"},"PeriodicalIF":2.0,"publicationDate":"2018-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49091525","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Quaternary radiolarian biostratigraphy in the subarctic northeastern Pacific (IODP Expedition 341 Site U1417) and synchroneity of bioevents across the North Pacific 东北太平洋亚北极地区第四纪放射虫生物地层学(IODP考察队341站点U1417)和北太平洋生物事件的同步性

IF 2 3区地球科学

Journal of Micropalaeontology Pub Date : 2018-01-05 DOI: 10.5194/JM-37-1-2018

K. Matsuzaki, N. Suzuki

{"title":"Quaternary radiolarian biostratigraphy in the subarctic northeastern Pacific (IODP Expedition 341 Site U1417) and synchroneity of bioevents across the North Pacific","authors":"K. Matsuzaki, N. Suzuki","doi":"10.5194/JM-37-1-2018","DOIUrl":"https://doi.org/10.5194/JM-37-1-2018","url":null,"abstract":"Abstract. Expedition 341 of the Integrated Ocean Drilling Program (IODP) retrieved sediment cores spanning the time interval between the Pleistocene and Miocene from the southern Gulf of Alaska. Onboard Pleistocene radiolarian biostratigraphy is hereby refined by increasing the sampling resolution. The 178 core samples from the upper 190 m CCSF-B (Composite Core Depth Scale F-B) of Site U1417 contained faunal elements similar to the northwestern Pacific; for example, the three biozones in the northwestern Pacific (i.e., Eucyrtidium matuyamai, Stylatractus universus and Botryostrobus aquilonaris) were also recognized in the Gulf of Alaska, spanning 1.80–1.13 Ma, 1.13–0.45 Ma, and the last 0.45 Myr, respectively. Based on the age model that we used in this study and the shipboard paleomagnetic reversal events, the first occurrences (FOs) of Amphimelissa setosa and Schizodiscus japonicus in the northeastern Pacific were preliminarily determined to be 1.48 and 1.30 Ma, respectively. The last occurrence (LO) of Eucyrtidium matuyamai and the FO of Lychnocanoma sakaii, both well-established bioevents in the northwestern Pacific, were dated at 0.80 and 1.13 Ma, respectively. The LO of E. matuyamai is a synchronous event at 1.05 ± 0.1 Ma in the North Pacific, while the FOs of A. setosa and S. japonicus at 1.48 and 1.30 Ma, respectively, are significantly older than what has been found elsewhere.","PeriodicalId":54786,"journal":{"name":"Journal of Micropalaeontology","volume":"37 1","pages":"1-10"},"PeriodicalIF":2.0,"publicationDate":"2018-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44892680","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 8

New species of Cenozoic benthic foraminifera from the former British Petroleum micropalaeontology collection 英国石油公司前微体化石中的新生代底栖有孔虫新种

IF 2 3区地球科学

Journal of Micropalaeontology Pub Date : 2018-01-05 DOI: 10.5194/JM-37-11-2018

Lyndsey R. Fox, Stephen Stukins, T. Hill, H. Bailey

引用次数: 1

“Live” (stained) benthic foraminiferal living depths, stable isotopes, and taxonomy offshore South Georgia, Southern Ocean: implications for calcification depths “活的”(染色的)底栖有孔虫生活深度，稳定同位素，以及南大洋南乔治亚近海的分类:钙化深度的含义

IF 2 3区地球科学

Journal of Micropalaeontology Pub Date : 2018-01-05 DOI: 10.5194/JM-37-25-2018

Rowan Dejardin, S. Kender, C. Allen, M. Leng, G. Swann, V. Peck

{"title":"“Live” (stained) benthic foraminiferal living depths, stable isotopes, and taxonomy offshore South Georgia, Southern Ocean: implications for calcification depths","authors":"Rowan Dejardin, S. Kender, C. Allen, M. Leng, G. Swann, V. Peck","doi":"10.5194/JM-37-25-2018","DOIUrl":"https://doi.org/10.5194/JM-37-25-2018","url":null,"abstract":"Abstract. It is widely held that benthic foraminifera exhibit species-specific calcification depth preferences, with their tests recording sediment pore water chemistry at that depth (i.e. stable isotope and trace metal compositions). This assumed depth-habitat-specific pore water chemistry relationship has been used to reconstruct various palaeoenvironmental parameters, such as bottom water oxygenation. However, many deep-water foraminiferal studies show wide intra-species variation in sediment living depth but relatively narrow intra-species variation in stable isotope composition. To investigate this depth-habitat–stable-isotope relationship on the shelf, we analysed depth distribution and stable isotopes of living (Rose Bengal stained) benthic foraminifera from two box cores collected on the South Georgia shelf (ranging from 250 to 300 m water depth). We provide a comprehensive taxonomic analysis of the benthic fauna, comprising 79 taxonomic groupings. The fauna shows close affinities with shelf assemblages from around Antarctica. We find live specimens of a number of calcareous species from a range of depths in the sediment column. Stable isotope ratios (δ13C and δ18O) were measured on stained specimens of three species, Astrononion echolsi, Cassidulinoides porrectus, and Buccella sp. 1, at 1 cm depth intervals within the downcore sediment sequences. In agreement with studies in deep-water settings, we find no significant intra-species variability in either δ13Cforam or δ18Oforam with sediment living depth on the South Georgia shelf. Our findings add to the growing evidence that infaunal benthic foraminiferal species calcify at a fixed depth. Given the wide range of depths at which we find living , infaunal species, we speculate that they may actually calcify predominantly at the sediment–seawater interface, where carbonate ion concentration and organic carbon availability is at a maximum.","PeriodicalId":54786,"journal":{"name":"Journal of Micropalaeontology","volume":"37 1","pages":"25-71"},"PeriodicalIF":2.0,"publicationDate":"2018-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41368892","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 6

Exceptionally well-preserved Permocalculus cf. tenellus (Pia) (Gymnocodiaceae) from Upper Permian Khuff Formation limestones, Saudi Arabia 沙特阿拉伯上二叠纪Khuff组石灰岩中保存异常完好的二叠石cf. tenellus (Pia)(裸子科)

IF 2 3区地球科学

Journal of Micropalaeontology Pub Date : 2017-04-27 DOI: 10.1144/jmpaleo2016-005

G. Hughes

{"title":"Exceptionally well-preserved Permocalculus cf. tenellus (Pia) (Gymnocodiaceae) from Upper Permian Khuff Formation limestones, Saudi Arabia","authors":"G. Hughes","doi":"10.1144/jmpaleo2016-005","DOIUrl":"https://doi.org/10.1144/jmpaleo2016-005","url":null,"abstract":"An exceptionally well-preserved specimen of the articulated rhodophyte Permocalculus, compared with P. tenellus sensu Elliott, 1955, is described from fine-grained Upper Permian limestones of the Khuff Formation of Saudi Arabia. Longitudinal medullary and sheaf-like cortical filaments extend through the uniserial series of elongate-globular, concave- and convex-terminating, interlocking segments for which they are interpreted to have functioned in articulation. The filaments tend to splay and branch laterally into the cortex where they terminate at the pores. At the terminal aperture, the filaments extend as bifurcating and possibly trifurcating branches and may serve as the origin of a new segment. Numerous elongate-globular chambers, up to five in each row and intimately involved with the filaments, are developed in the outer medulla and are considered to represent reproductive sporangia. The specimen is considered to have occupied predominantly low-energy, normal to slightly elevated salinity, shallow conditions within the subtidal regime of a lagoon.","PeriodicalId":54786,"journal":{"name":"Journal of Micropalaeontology","volume":"36 1","pages":"166 - 173"},"PeriodicalIF":2.0,"publicationDate":"2017-04-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1144/jmpaleo2016-005","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45538575","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Modern deep-water agglutinated foraminifera from IODP Expedition 323, Bering Sea: ecological and taxonomic implications 白令海IODP远征323的现代深水凝集有孔虫：生态学和分类学意义

IF 2 3区地球科学

Journal of Micropalaeontology Pub Date : 2017-04-05 DOI: 10.1144/jmpaleo2016-026

S. Kender, M. Kaminski

{"title":"Modern deep-water agglutinated foraminifera from IODP Expedition 323, Bering Sea: ecological and taxonomic implications","authors":"S. Kender, M. Kaminski","doi":"10.1144/jmpaleo2016-026","DOIUrl":"https://doi.org/10.1144/jmpaleo2016-026","url":null,"abstract":"Despite the importance of the Bering Sea for subarctic oceanography and climate, relatively little is known of the foraminifera from the extensive Aleutian Basin. We report the occurrence of modern deep-water agglutinated foraminifera collected at seven sites cored during Integrated Ocean Drilling Program (IODP) Expedition 323 in the Bering Sea. Assemblages collected from core-top samples contained 32 genera and 50 species and are described and illustrated here for the first time. Commonly occurring species include typical deep-water Rhizammina, Reophax, Rhabdammina, Recurvoides and Nodulina. Assemblages from the northern sites also consist of accessory Cyclammina, Eggerelloides and Glaphyrammina, whilst those of the Bowers Ridge sites consist of other tubular genera and Martinottiella. Of the studied stations with the lowest dissolved oxygen concentrations, the potentially Bering Sea endemic Eggerelloides sp. 1 inhabits the northern slope, which has the highest primary productivity, and the potentially endemic Martinottiella sp. 3 inhabits Bowers Ridge, which has the lowest oxygen concentrations but relatively low annual productivity. Martinottiella sp. 3, with open pores on its test surface, has previously been reported in Pliocene to Recent material from Bowers Ridge. Despite relatively small sample sizes, ecological constraints may imply that the Bering Sea experienced high productivity and reduced oxygen at times since at least the Pliocene. We note the partially endemic nature of the agglutinated foraminiferal assemblages, which may at least in part be due to basin restriction, the geologically long time period of reduced oxygen, and high organic carbon flux. Our results indicate the importance of gathering further surface sample data from the Aleutian Basin.","PeriodicalId":54786,"journal":{"name":"Journal of Micropalaeontology","volume":"36 1","pages":"195 - 218"},"PeriodicalIF":2.0,"publicationDate":"2017-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1144/jmpaleo2016-026","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48380226","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 11

On the Cretaceous origin of the Order Syracosphaerales and the genus Syracosphaera 论白垩纪雪龙目和雪龙属的起源

IF 2 3区地球科学

Journal of Micropalaeontology Pub Date : 2017-03-31 DOI: 10.1144/jmpaleo2016-001

P. Bown, J. Young, J. Lees

{"title":"On the Cretaceous origin of the Order Syracosphaerales and the genus Syracosphaera","authors":"P. Bown, J. Young, J. Lees","doi":"10.1144/jmpaleo2016-001","DOIUrl":"https://doi.org/10.1144/jmpaleo2016-001","url":null,"abstract":"New scanning electron microscope observations of unadulterated calcareous nannofossil assemblages on lamina surfaces of Cretaceous Tanzania Drilling Project sediments reveal high diversity in the <3 µm size-range and high abundances of small and frangible morphologies. These assemblages prompt comparison to modern assemblages, which show similar high diversity and abundance of very small and fragile taxa, although these assemblages are generally not preserved in the fossil record due to taphonomic filtering. Not only are there broad similarities between the general composition of modern assemblages and those of the Tanzanian lagerstätte, but also our discovery of several new Cretaceous taxa provides evidence for greatly extended fossil lineages of extant orders, with implications for both deep-time biodiversity divergence and survival through the end-Cretaceous mass extinction. Our findings include: new species that are the first-recorded Mesozoic representatives of the extant Syracosphaeraceae and Papposphaeraceae; potentially previously unrecorded diversity in the Mesozoic Calciosoleniaceae, another extant order, represented by extant species that have been described already; and new species and unusually high abundances of the Mesozoic Stephanolithiaceae. We also highlight the extended range of an incertae sedis Cenozoic genus, Ellipsolithus, into at least the Turonian. Here, we describe seven new miniscule to very small Cretaceous species: Syracosphaera antiqua, S. repagula, Pocillithus macleodii, P. crucifer, Stradnerlithus wendleri, S.? haynesiae and Tortolithus foramen.","PeriodicalId":54786,"journal":{"name":"Journal of Micropalaeontology","volume":"36 1","pages":"153 - 165"},"PeriodicalIF":2.0,"publicationDate":"2017-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1144/jmpaleo2016-001","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48739438","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 5

Effect of gross morphology on modern planktonic foraminiferal test strength under compression 粗大形态对现代浮游有孔虫压缩试验强度的影响

IF 2 3区地球科学

Journal of Micropalaeontology Pub Date : 2017-03-31 DOI: 10.1144/jmpaleo2016-007

Janet E. Burke, P. Hull

{"title":"Effect of gross morphology on modern planktonic foraminiferal test strength under compression","authors":"Janet E. Burke, P. Hull","doi":"10.1144/jmpaleo2016-007","DOIUrl":"https://doi.org/10.1144/jmpaleo2016-007","url":null,"abstract":"Planktonic foraminifera are a source of important geochemical, palaeoceanographic, and palaeontological data. However, many aspects of their ecology remain poorly understood, including whether or not gross morphology has an ecological function. Here, we measure the force needed to crush multiple planktonic foraminiferal morphotypes from modern core top and tow samples. We find significant differences in the resistance of different morphotypes to compressional force. Three species, Globorotalia tumida (biconvex, keeled), Menardella menardii (discoidal, keeled), Truncorotalia truncatulinoides (conical, keeled), require on average 59% more force (1.07 v. 0.47 N) to crush than the least resistant species (Orbulina universa and Trilobatus sacculifer) in core-top samples. Towed samples of pre-gametogenic individuals also show significant differences of the same magnitude (0.693 v. 0.53 N) between the conical (T. truncatulinoides) and globular/spherical morphologies (Globoconella inflata and O. universa). We hypothesize that the greater compressional strength of certain shapes confers a fitness advantage against predators and could contribute to the repeated, convergent evolution of keeled, conical and bi-convex forms in planktonic foraminifer lineages. Supplementary material: Raw data for all crushing experiments, wall thickness measurements, and results for all pair-wise Kolmogorov-Smirnov Tests are available at https://doi.org/10.6084/m9.figshare.c.3725236.v1","PeriodicalId":54786,"journal":{"name":"Journal of Micropalaeontology","volume":"36 1","pages":"174 - 182"},"PeriodicalIF":2.0,"publicationDate":"2017-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1144/jmpaleo2016-007","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47534792","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 5

An aberrant bi-apical Follicucullus (Albaillellaria) from the late Guadalupian (Middle Permian), with the possible oldest evidence of double malformation in radiolarians 一种来自瓜达鲁阶晚期（二叠纪中期）的异常双顶端毛囊（Albailellaria），可能是放射虫双重畸形的最古老证据

IF 2 3区地球科学

Journal of Micropalaeontology Pub Date : 2017-03-30 DOI: 10.1144/jmpaleo2016-016

Tsuyoshi Ito, Y. Kitagawa, A. Matsuoka

引用次数: 4

Cyprideis (Crustacea, Ostracoda) in Australia 澳大利亚的介形虫(甲壳纲，介形虫纲)

IF 2 3区地球科学

Journal of Micropalaeontology Pub Date : 2017-01-01 DOI: 10.1144/jmpaleo2016-032

I. Schön, S. Halse, K. Martens

引用次数: 8