Seyyed Khalil Forouzande, M. Hadi, M. Vahidinia, L. Consorti, A. Salahi, M. H. M. Gharaie, Ercan Ozcan
Eocene larger benthic foraminifera including orthophragmines, nummulitids and alveolinids from the Jahrum and Pabdeh formations in the Zagros region are presented. The studied 20-m-thick stratigraphic interval contains, Asterocyclina Gumbel 1870, Nemkovella Less 1987, Orbitoclypeus Silvestri 1907, Discocyclina Gumbel 1870, Nummulites Lamarck 1801, Assilina d'Orbigny 1826 and Alveolina d'Orbigny 1826. This larger benthic foraminiferal assemblage testifies for the shallow benthic zones (SBZs) 15 to 17, which ranges from the middle Lutetian up to the early Bartonian. Further micropaleontological analysis made on intercalated planktonic-rich levels helps calibrate the larger foraminifera biostratigraphy, demonstrating a correlation with the E11 biozone. This confirms that the chronostratigraphic calibration of the SBZs made by previous authors for the peri-Mediterranean area can, through the middle Lutetian to the early Bartonian, be applicable in the Middle East as well.
{"title":"Biostratigraphy of larger foraminifera from the Middle Eocene Jahrum-Pabdeh formations (Zagros region, SW Iran) and their correlation with the planktonic foraminiferal zones","authors":"Seyyed Khalil Forouzande, M. Hadi, M. Vahidinia, L. Consorti, A. Salahi, M. H. M. Gharaie, Ercan Ozcan","doi":"10.47894/mpal.69.4.05","DOIUrl":"https://doi.org/10.47894/mpal.69.4.05","url":null,"abstract":"Eocene larger benthic foraminifera including orthophragmines, nummulitids and alveolinids from the Jahrum and Pabdeh formations in the Zagros region are presented. The studied 20-m-thick stratigraphic interval contains, Asterocyclina Gumbel 1870, Nemkovella Less 1987, Orbitoclypeus Silvestri 1907, Discocyclina Gumbel 1870, Nummulites Lamarck 1801, Assilina d'Orbigny 1826 and Alveolina d'Orbigny 1826. This larger benthic foraminiferal assemblage testifies for the shallow benthic zones (SBZs) 15 to 17, which ranges from the middle Lutetian up to the early Bartonian. Further micropaleontological analysis made on intercalated planktonic-rich levels helps calibrate the larger foraminifera biostratigraphy, demonstrating a correlation with the E11 biozone. This confirms that the chronostratigraphic calibration of the SBZs made by previous authors for the peri-Mediterranean area can, through the middle Lutetian to the early Bartonian, be applicable in the Middle East as well.","PeriodicalId":49816,"journal":{"name":"Micropaleontology","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70447319","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Hadi, Seyyed Khalil Forouzande, L. Consorti, M. Parandavar, M. Vahidinia
A biometrical study on four reticulate Nummulites populations from the lower part ofAsmari Formation of the Vazag section (Zagros zone) is carried out. The biostratigraphy obtained by studing the succession points to the Early Oligocene (Rupelian), indicating shallow benthic zones SBZ21 and SBZ22A by the occurrence of Operculina cf. complanata, Eulepidina formosoides, Nephrolepidina sp. The age assignment is calibrated with calcareous nannofossils biostratigraphy indicating the NP22-NP23 (=CNO2-CNO3) Zones.We have observed a stratigraphic trend related to Nummulites bormidiensis Tellini 1888 that results to be characterized by two populations composed of transitional Nummulites fichteli/bormidiensis with values of mean inner proloculus that exceeds by very little the boundary commonly established at 300 um. Such a populations, indicated as Nummulites ex interc. bormidiensis et fichteli, span through the lower Rupelianwhere classically just N. fichteli is reported so far. The stratigraphic distribution of Nummulites bormidiensisis and related transitional forms is here stretched to the Rupelian (SBZ21 and SBZ22A), encompassing older ages than previously recorded throughout the Neo-Tethys Ocean.
对Vazag剖面(Zagros带)asmari组下部的4个网状Nummulites种群进行了生物统计学研究。通过演替研究得到的生物地层学指向早渐新世(鲁比利世)，由Operculina cf.complanata、Eulepidina formosoides、Nephrolepidina sp的出现确定了SBZ21和SBZ22A浅层底栖生物带。用钙质纳米化石生物地层学校正了年龄，确定了NP22-NP23 (=CNO2-CNO3)带。我们观察到一个与Nummulites bormidiensis Tellini 1888有关的地层趋势，其特征是两个由过渡性Nummulites fichteli/bormidiensis组成的种群，其平均内前位值仅超过通常在300 um建立的边界。这样的种群，表示为Nummulites ex intercbormiddiensis et fichteli，跨越rupelia下部，到目前为止，传统上只报道了N. fichteli。在这里，Nummulites bormidensis及其相关过渡形态的地层分布延伸到鲁比利期(SBZ21和SBZ22A)，比以前记录的整个新特提斯洋的年龄更大。
{"title":"Extending the stratigraphic range of Nummulites bormidiensis Tellini in the Neo-Tethys (Zagros basin, SE Iran) through biometry and calcareous nannofossil biostratigraphy","authors":"M. Hadi, Seyyed Khalil Forouzande, L. Consorti, M. Parandavar, M. Vahidinia","doi":"10.47894/mpal.69.4.06","DOIUrl":"https://doi.org/10.47894/mpal.69.4.06","url":null,"abstract":"A biometrical study on four reticulate Nummulites populations from the lower part ofAsmari Formation of the Vazag section (Zagros zone) is carried out. The biostratigraphy obtained by studing the succession points to the Early Oligocene (Rupelian), indicating shallow benthic zones SBZ21 and SBZ22A by the occurrence of Operculina cf. complanata, Eulepidina formosoides, Nephrolepidina sp. The age assignment is calibrated with calcareous nannofossils biostratigraphy indicating the NP22-NP23 (=CNO2-CNO3) Zones.We have observed a stratigraphic trend related to Nummulites bormidiensis Tellini 1888 that results to be characterized by two populations composed of transitional Nummulites fichteli/bormidiensis with values of mean inner proloculus that exceeds by very little the boundary commonly established at 300 um. Such a populations, indicated as Nummulites ex interc. bormidiensis et fichteli, span through the lower Rupelianwhere classically just N. fichteli is reported so far. The stratigraphic distribution of Nummulites bormidiensisis and related transitional forms is here stretched to the Rupelian (SBZ21 and SBZ22A), encompassing older ages than previously recorded throughout the Neo-Tethys Ocean.","PeriodicalId":49816,"journal":{"name":"Micropaleontology","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70447328","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
B. Hayward, M. Holzmann, J. Pawłowski, J. Wollenburg, W. Majewski
DNA sequencing shows that species of the genera Notorotalia, Porosorotalia and Buccella form a distinct branch (Notorotaliidae) of Rotaloidea, and cluster as sister to Elphidiidae. In this review we report on the sequencing of three species of Buccella (from the Arctic Ocean, Patagonia and Chile) and one each of Notorotalia (New Zealand) and Porosorotalia (Chile). This information has been combined with all the morphological descriptive information on species of these genera plus the genera Cristatavultus and Parrellina to provide a global synthesis of living species of the Notorotaliidae. We recognize 11 species of the southern hemisphere genus Notorotalia, which has a centre of diversity around New Zealand (8 species). A second southern-hemisphere-restricted genus, restricted to eastern Australia is Parrellina (3 species) although specimens (possibly introduced) have been recorded from the Mediterranean Sea. Cristatavultus has a single species, with a tropical west Pacific distribution.We synonymize Cribrorotalia under Porosorotalia, which has a disjunct distribution with one species in the northwest Pacific and a second around the southern parts of South America. Buccella is the most diverse and widespread genus (16 species recognized) with its greatest abundance in the Arctic Ocean and around subantarctic-temperate South America. Five species of Buccella live in a belt along the west coast of central America, from USA to Peru, with some spillage into the Caribbean Sea and Gulf of Mexico. Two new species of Buccella are recognized: B. dejardini (from South Georgia) and Buccella n. sp. A (from Chile).
{"title":"Taxonomy and biogeography of living species of the Family Notorotaliidae (Notorotalia, Parrellina, Porosorotalia, Buccella, Cristatavultus)","authors":"B. Hayward, M. Holzmann, J. Pawłowski, J. Wollenburg, W. Majewski","doi":"10.47894/mpal.69.3.01","DOIUrl":"https://doi.org/10.47894/mpal.69.3.01","url":null,"abstract":"DNA sequencing shows that species of the genera Notorotalia, Porosorotalia and Buccella form a distinct branch (Notorotaliidae) of Rotaloidea, and cluster as sister to Elphidiidae. In this review we report on the sequencing of three species of Buccella (from the Arctic Ocean, Patagonia and Chile) and one each of Notorotalia (New Zealand) and Porosorotalia (Chile). This information has been combined with all the morphological descriptive information on species of these genera plus the genera Cristatavultus and Parrellina to provide a global synthesis of living species of the Notorotaliidae. We recognize 11 species of the southern hemisphere genus Notorotalia, which has a centre of diversity around New Zealand (8 species). A second southern-hemisphere-restricted genus, restricted to eastern Australia is Parrellina (3 species) although specimens (possibly introduced) have been recorded from the Mediterranean Sea. Cristatavultus has a single species, with a tropical west Pacific distribution.We synonymize Cribrorotalia under Porosorotalia, which has a disjunct distribution with one species in the northwest Pacific and a second around the southern parts of South America. Buccella is the most diverse and widespread genus (16 species recognized) with its greatest abundance in the Arctic Ocean and around subantarctic-temperate South America. Five species of Buccella live in a belt along the west coast of central America, from USA to Peru, with some spillage into the Caribbean Sea and Gulf of Mexico. Two new species of Buccella are recognized: B. dejardini (from South Georgia) and Buccella n. sp. A (from Chile).","PeriodicalId":49816,"journal":{"name":"Micropaleontology","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70447369","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Forty-three species belonging to thirty-seven genera of benthic foraminifera were differentiated from the Eocene Shitakara Formation in the eastern part of the Kushiro Coalfield, eastern Hokkaido. The foraminiferal assemblages show upward transgression from the inner to outer sublittoral condition. They contain abundant agglutinated and calcareous hyaline benthic species, including Labrospira crassiformis, Haplophragmoides subamakusaensis, and Cribroelphidium sorachiense, indicating similarity to the Eocene fauna in central Hokkaido. Two planktonic species Chiloguembelina ototara and Tenuitella insolita also indicate a late Eocene age. Neotype specimens of Cyclammina pacifica var. kushiroensis, Nonion kushiroense, and Nonion sorachiense var. konbumoriense described by Yoshida (1957) have been designated as replacements for holotype specimens that were lost in a fire in May 1965. A taxonomical reexamination based on the neotypes and topotypes indicates that Cyclammina pacifica var. kushiroensis is a distinct species, whereas Nonion kushiroense and Nonion sorachiense var. konbumoriense are junior synonyms of Cribroelphidium sorachiense (Asano 1954). All foraminiferal taxa are illustrated with taxonomical notes.
在北海道东部Kushiro煤田东部始新世Shitakara组中鉴定出底栖有孔虫43种，隶属37属。有孔虫组合表现为自下而上向外的海侵。其中含有丰富的凝集和钙质透明底栖动物，包括Labrospira crassiformis、Haplophragmoides subamakusaensis和Cribroelphidium sorachiense，与北海道中部始新世的动物群相似。两个浮游物种Chiloguembelina ototara和Tenuitella solinita也表明始新世晚期。吉田(1957)描述的Cyclammina pacifica var. kushiroensis、Nonion kushiroense和Nonion sorachiense var. konbumoriense的新模式标本已被指定为1965年5月火灾中丢失的全模式标本的替代品。基于新型和拓扑型的分类学研究表明，Cyclammina pacifica var. kushiroensis是一个独立的种，而Nonion kushiroense和Nonion sorachiense var. konbumoriense是Cribroelphidium sorachiense的低级同义种(Asano 1954)。所有有孔虫分类都附有分类注释。
{"title":"Foraminifera of the Eocene Shitakara Formation in eastern Hokkaido, with the designation of neotype specimens of Yoshida (1957)","authors":"Satoshi Hanagata, Den Matsue, T. Matsubara","doi":"10.47894/mpal.69.3.02","DOIUrl":"https://doi.org/10.47894/mpal.69.3.02","url":null,"abstract":"Forty-three species belonging to thirty-seven genera of benthic foraminifera were differentiated from the Eocene Shitakara Formation in the eastern part of the Kushiro Coalfield, eastern Hokkaido. The foraminiferal assemblages show upward transgression from the inner to outer sublittoral condition. They contain abundant agglutinated and calcareous hyaline benthic species, including Labrospira crassiformis, Haplophragmoides subamakusaensis, and Cribroelphidium sorachiense, indicating similarity to the Eocene fauna in central Hokkaido. Two planktonic species Chiloguembelina ototara and Tenuitella insolita also indicate a late Eocene age. Neotype specimens of Cyclammina pacifica var. kushiroensis, Nonion kushiroense, and Nonion sorachiense var. konbumoriense described by Yoshida (1957) have been designated as replacements for holotype specimens that were lost in a fire in May 1965. A taxonomical reexamination based on the neotypes and topotypes indicates that Cyclammina pacifica var. kushiroensis is a distinct species, whereas Nonion kushiroense and Nonion sorachiense var. konbumoriense are junior synonyms of Cribroelphidium sorachiense (Asano 1954). All foraminiferal taxa are illustrated with taxonomical notes.","PeriodicalId":49816,"journal":{"name":"Micropaleontology","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70447465","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Advances in the biostratigraphy of Paleogene larger benthic foraminifera","authors":"M. Kaminski, A. Briguglio","doi":"10.47894/mpal.69.4.01","DOIUrl":"https://doi.org/10.47894/mpal.69.4.01","url":null,"abstract":"Introduction","PeriodicalId":49816,"journal":{"name":"Micropaleontology","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70447617","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Small reticulate Nummulites are found across the Eocene shallow marine deposits of the Paris Basin, Belgium, as far north as northern Germany and southern United Kingdom. Only two isolated instances of Nummulites at higher latitudes than this are known, from the Rockall bank and Wyville-Thomson ridge in the north Atlantic, and no Nummulites have been reported from the Nordic North Sea Basin - until now. Here Nummulites planulatus is described within a glacial erratic dredged from Jyske Rev in the Danish North Sea of likelyYpresian age.Whilst the specimen is not in situ, it indicates that populations of Nummulites were living further north in the North Sea region than previously known. This range expansion may have been facilitated by the hyperthermal events of the early Eocene.
{"title":"Nordic Nummulites: An unusual occurrence of Nummulites planulatus from Jyske Rev, Danish North Sea","authors":"L. Cotton","doi":"10.47894/mpal.69.4.08","DOIUrl":"https://doi.org/10.47894/mpal.69.4.08","url":null,"abstract":"Small reticulate Nummulites are found across the Eocene shallow marine deposits of the Paris Basin, Belgium, as far north as northern Germany and southern United Kingdom. Only two isolated instances of Nummulites at higher latitudes than this are known, from the Rockall bank and Wyville-Thomson ridge in the north Atlantic, and no Nummulites have been reported from the Nordic North Sea Basin - until now. Here Nummulites planulatus is described within a glacial erratic dredged from Jyske Rev in the Danish North Sea of likelyYpresian age.Whilst the specimen is not in situ, it indicates that populations of Nummulites were living further north in the North Sea region than previously known. This range expansion may have been facilitated by the hyperthermal events of the early Eocene.","PeriodicalId":49816,"journal":{"name":"Micropaleontology","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70448061","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Peter O. Baumgartner, Xin Li, Atsushi Matsuoka, Christian Vérard
The aim of this report is to 1) to formally describe Austral and Subtropical Gyre Radiolaria recovered from ODP Hole 123-765C), 2) to compare them with published records of Southern Hemisphere “non-Tethyan” assemblages and 3) to discuss radiolarian paleobiogeography of the Southern Hemisphere and its implications for global climate change during the Jurassic–Cretaceous transition. The Tithonian to Aptian/early Albian radiolarian record recovered from Hole 765C, Cores -62R to -36R in the Argo Abyssal Plain (AAP) is unique in its density of well-preserved samples and in its faunal contents. Radiolaria recovered from claystones yielded the low diversity, ecologically tolerant “Crypto-Archaeo” Assemblage, (chiefly cryptocephalic and cryptothoracic nassellarians and Archeodictyomitra spp.) interpreted herein as originated in the Subtropical Gyre (STG). In contrast, assemblages extracted from radiolarite layers, interpreted as pelagic turbidites derived from the deeper Australian margin, are dominated by Austral taxa. Neotethyan taxa are very rare to absent before the late Hauterivian/Barremian, when they gradually gain in diversity and abundance. Described Austral and STG taxa include 10 families, of which Fusitanellidae n. fam. and Windaliinae n. subfam. are new. Of 18 genera 7 are new (Nodosphaera, Praewindalia, Pachycingula, Archaeotanella, Morchella, Fusitanella, Argofusus) and of 55 species 30 new ones are formally described and 14 new ones are left in open nomenclature. The southern hemisphere Late Jurassic to Early Cretaceous radiolarian biogeography is defined from low- to high latitude: 1. the Neotethyan (NT) and 2. the Central Panthalassan (CP) realms, 3. Eastern Boundary Current (EBC) realm, 4. the Subtropical Gyre (STG) and the Austral (A) circum south-polar realm. Radiolarian biogeography and plate tectonic models support a scenario of palaeoceanographic and global climatic change during the Jurassic–Cretaceous transition related to progressive Pangea break-up with the following consequences: 1. an increased heat transfer to the Southern hemisphere which caused cooling of Neotethyan regions during the Late Tithonian dry event. 2. A northward shift of the southern summer Intertropical Conve nience Zone reduced the Neotethyan monsoon area and allowed the establishment of a southern Neotethyan subtropical gyre documented by the “Crypo-Archaeo” Assemblage. 3. The south-polar West Wind Drift may have forced a circum Antarctic-Australian cold current through the epicontinental rift between India and Antarctica-Australia since the Berriasian (140 my), transporting Austral Radiolaria into the AAP where they accumulated in radiolarite layers.
本报告的目的是1)正式描述从ODP孔123-765C中恢复的南方和亚热带环流放射虫，2)将它们与南半球“非特提斯”组合的已发表记录进行比较，3)讨论南半球放射虫古生物地理学及其对侏罗纪-白垩纪过渡期间全球气候变化的影响。在阿尔戈深海平原(AAP) -62R至-36R岩芯765C孔中发现的泰通世至阿普梯世/早期阿普梯世放射虫记录，其保存完好的样品密度和动物含量都是独一无二的。从粘土中恢复的放射虫产生了低多样性，生态耐受的“隐古”组合，(主要是隐头和隐胸鼻虫和archaeodictyomitra spp)，本文解释为起源于亚热带环流(STG)。相比之下，从放射石层中提取的组合，被解释为来自澳大利亚更深边缘的上层浊积岩，主要由澳大利亚分类群组成。在Hauterivian/Barremian晚期之前，新特提斯的分类群非常罕见或缺失，当它们逐渐获得多样性和丰富性时。已描述的Austral和STG分类群包括10科，其中Fusitanellidae n. fam。和Windaliinae n. subfam。都是新的。18个属中有7个是新属(Nodosphaera, Praewindalia, Pachycingula, Archaeotanella, Morchella, Fusitanella, Argofusus)， 55个种中有30个新属被正式描述，14个新属被公开命名。南半球晚侏罗世至早白垩世放射虫生物地理从低纬度到高纬度定义:新特提斯(NT)和2。中央泛thalassan (CP)领域，3。东边界流(EBC)领域，4。副热带环流(STG)和南极圈(A)围绕南极地区。放射虫生物地理学和板块构造模型支持侏罗纪-白垩纪过渡时期的古海洋学和全球气候变化情景，该情景与盘古大陆的渐进分裂有关，其结果如下:增加的热量传递到南半球，导致新特提斯地区在晚泰托尼亚干旱事件期间变冷。2. 南部夏季热带便利带的北移减少了新特提斯季风区，并使新特提斯南部亚热带环流的建立成为可能。自Berriasian(140年)以来，南极西风流可能迫使一股环南极-澳大利亚寒流穿过印度和南极-澳大利亚之间的大陆外裂谷，将南极光虫运送到AAP，在那里它们积聚在辐射虫层中。
{"title":"Austral and Subtropical Gyre Radiolaria – latest Jurassic to Early Cretaceous Leg 123, Site 765, Argo Abyssal Plain revisited: Southern Hemisphere paleobiogeography and global climate change","authors":"Peter O. Baumgartner, Xin Li, Atsushi Matsuoka, Christian Vérard","doi":"10.47894/mpal.69.6.01","DOIUrl":"https://doi.org/10.47894/mpal.69.6.01","url":null,"abstract":"The aim of this report is to 1) to formally describe Austral and Subtropical Gyre Radiolaria recovered from ODP Hole 123-765C), 2) to compare them with published records of Southern Hemisphere “non-Tethyan” assemblages and 3) to discuss radiolarian paleobiogeography of the Southern Hemisphere and its implications for global climate change during the Jurassic–Cretaceous transition. The Tithonian to Aptian/early Albian radiolarian record recovered from Hole 765C, Cores -62R to -36R in the Argo Abyssal Plain (AAP) is unique in its density of well-preserved samples and in its faunal contents. Radiolaria recovered from claystones yielded the low diversity, ecologically tolerant “Crypto-Archaeo” Assemblage, (chiefly cryptocephalic and cryptothoracic nassellarians and Archeodictyomitra spp.) interpreted herein as originated in the Subtropical Gyre (STG). In contrast, assemblages extracted from radiolarite layers, interpreted as pelagic turbidites derived from the deeper Australian margin, are dominated by Austral taxa. Neotethyan taxa are very rare to absent before the late Hauterivian/Barremian, when they gradually gain in diversity and abundance. Described Austral and STG taxa include 10 families, of which Fusitanellidae n. fam. and Windaliinae n. subfam. are new. Of 18 genera 7 are new (Nodosphaera, Praewindalia, Pachycingula, Archaeotanella, Morchella, Fusitanella, Argofusus) and of 55 species 30 new ones are formally described and 14 new ones are left in open nomenclature. The southern hemisphere Late Jurassic to Early Cretaceous radiolarian biogeography is defined from low- to high latitude: 1. the Neotethyan (NT) and 2. the Central Panthalassan (CP) realms, 3. Eastern Boundary Current (EBC) realm, 4. the Subtropical Gyre (STG) and the Austral (A) circum south-polar realm. Radiolarian biogeography and plate tectonic models support a scenario of palaeoceanographic and global climatic change during the Jurassic–Cretaceous transition related to progressive Pangea break-up with the following consequences: 1. an increased heat transfer to the Southern hemisphere which caused cooling of Neotethyan regions during the Late Tithonian dry event. 2. A northward shift of the southern summer Intertropical Conve nience Zone reduced the Neotethyan monsoon area and allowed the establishment of a southern Neotethyan subtropical gyre documented by the “Crypo-Archaeo” Assemblage. 3. The south-polar West Wind Drift may have forced a circum Antarctic-Australian cold current through the epicontinental rift between India and Antarctica-Australia since the Berriasian (140 my), transporting Austral Radiolaria into the AAP where they accumulated in radiolarite layers.","PeriodicalId":49816,"journal":{"name":"Micropaleontology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135445406","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Organic-walled marine microplankton from the Hauterivian and early Barremian of the North Sea Region - biostratigraphy and taxonomy","authors":"S. Duxbury","doi":"10.47894/mpal.69.2.01","DOIUrl":"https://doi.org/10.47894/mpal.69.2.01","url":null,"abstract":"","PeriodicalId":49816,"journal":{"name":"Micropaleontology","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70447206","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
C. Ferràndez-Cañadell, C. Baumgartner‐Mora, Peter Baumgartner, J. Epard
Here, we revise and update the biostratigraphy of larger foraminiferal assemblages in three sections of the Priabonian Sanetsch Formation in the Helvetic Nappes of theWestern Swiss Alps: The SexRouge (SE) and the Sanetsch Buvette (SA) sections in the Wildhorn Nappe Complex, and the Col des Essets (ETS) section in the most external Morcles Nappe. In the SE and SA sections, the Tsanfleuron and most of the Pierredar Limestone members of the formation are assigned to SBZ 19 (early Priabonian), while the uppermost part of the formation is assigned to SBZ 20 (late Priabonian). In the external ETS section the entire Sanetsch Formation contains assemblages characteristic of SBZ 19, suggesting an earlier, middle-late Priabonian onset of the hemipelagic Stad Formation (Globigerina Marls). Since it was established in 1998, the Shallow Benthic Zones (SBZ), a biozonation based on larger foraminifera, has been a useful tool in the biostratigraphy of the Paleogene. Biozonation proposals for the late middle-late Eocene are based mainly in biometrical subdivision of lineages of nummulitids and orthophragmines,which requiresmeasurements in oriented sections of isolated specimens. Here, we define previously unreported taxa from the Sanetsch Formation, which are considered characteristic for the Priabonian. They are easy to identify in random sections and thus useful biostratigraphical markers.We also describe a new orthophragminid genus, Virgasterocylina n. gen. (Orbitoclypeidae) characterized by the presence of rods, radial thickenings of calcite along ribs; a new species of Rotorbinella, R. epardi n. sp., and a new genus and new species of difficult suprageneric attribution, Sanetschella indeprensa n. gen., n. sp. We add the new taxa to the larger foraminiferal association characterizing the Priabonian (SBZ 19-20). The revision of the literature, together with our own sample collections revealed that these new taxa occur in Priabonian rocks from different basins in the western Tethys. Virgasterocylina n. gen. also occurs in the Caribbean bioprovince in the middle and upper Eocene. In the western Tethys, Virgasterocylina ferrandezi is subdivided into two subspecies, V. f. ferrandezi (Ozcan and Less) and V. f. lessi n. ssp., which characterize the SBZ 19 and 20 biozones respectively.
本文对瑞士西部阿尔卑斯山脉Helvetic推覆体Priabonian Sanetsch组的三个剖面进行了较大有孔虫组合的生物地层学校正和更新:Wildhorn推覆复合体的SexRouge (SE)和Sanetsch Buvette (SA)剖面，以及最外部Morcles推覆体的coldes Essets (ETS)剖面。在东南段和南段，Tsanfleuron组和大部分皮埃尔达尔灰岩段被划分为sbz19(早普里亚盆世)，而该组的上部被划分为sbz20(晚普里亚盆世)。在外部ETS剖面中，整个Sanetsch组包含sbz19特征的组合，表明半深海Stad组(Globigerina Marls)早中晚期开始。自1998年建立以来，以大型有孔虫为基础的浅层底栖带(SBZ)一直是古近系生物地层学的一个有用工具。始新世晚期-中晚期的生物分带建议主要基于对多聚体和正聚体谱系的生物特征细分，这需要在孤立标本的定向切片上进行测量。在这里，我们定义了以前未报道的Sanetsch组分类群，这些分类群被认为是Priabonian的特征。它们很容易在随机剖面中识别，因此是有用的生物地层标志。我们还描述了一种新的正片龙属，Virgasterocylina n. gen (Orbitoclypeidae)，其特征是存在棒状，方解石沿肋骨呈放射状增厚;Rotorbinella, R. epardi n. sp.一新种，Sanetschella indeprensa n. gen.， n. sp.一新属和一新种。我们将这个新分类群添加到Priabonian (SBZ 19-20)的大有孔虫群中。通过对文献的修订和我们自己收集的样品，我们发现这些新的分类群出现在特提斯西部不同盆地的普里亚伯纪岩石中。Virgasterocylina n. gen.也出现在始新世中上加勒比海生物省。在特提斯岛西部，ferrandezi被细分为两个亚种，V. f. ferrandezi (Ozcan和Less)和V. f. lessi n. ssp。，分别代表sbz19和sbz20生物带。
{"title":"Priabonian (upper Eocene) larger foraminifera from the Helvetic Nappes of the Alps (Western Switzerland): new markers for Shallow Benthic zones 19-20","authors":"C. Ferràndez-Cañadell, C. Baumgartner‐Mora, Peter Baumgartner, J. Epard","doi":"10.47894/mpal.69.4.03","DOIUrl":"https://doi.org/10.47894/mpal.69.4.03","url":null,"abstract":"Here, we revise and update the biostratigraphy of larger foraminiferal assemblages in three sections of the Priabonian Sanetsch Formation in the Helvetic Nappes of theWestern Swiss Alps: The SexRouge (SE) and the Sanetsch Buvette (SA) sections in the Wildhorn Nappe Complex, and the Col des Essets (ETS) section in the most external Morcles Nappe. In the SE and SA sections, the Tsanfleuron and most of the Pierredar Limestone members of the formation are assigned to SBZ 19 (early Priabonian), while the uppermost part of the formation is assigned to SBZ 20 (late Priabonian). In the external ETS section the entire Sanetsch Formation contains assemblages characteristic of SBZ 19, suggesting an earlier, middle-late Priabonian onset of the hemipelagic Stad Formation (Globigerina Marls). Since it was established in 1998, the Shallow Benthic Zones (SBZ), a biozonation based on larger foraminifera, has been a useful tool in the biostratigraphy of the Paleogene. Biozonation proposals for the late middle-late Eocene are based mainly in biometrical subdivision of lineages of nummulitids and orthophragmines,which requiresmeasurements in oriented sections of isolated specimens. Here, we define previously unreported taxa from the Sanetsch Formation, which are considered characteristic for the Priabonian. They are easy to identify in random sections and thus useful biostratigraphical markers.We also describe a new orthophragminid genus, Virgasterocylina n. gen. (Orbitoclypeidae) characterized by the presence of rods, radial thickenings of calcite along ribs; a new species of Rotorbinella, R. epardi n. sp., and a new genus and new species of difficult suprageneric attribution, Sanetschella indeprensa n. gen., n. sp. We add the new taxa to the larger foraminiferal association characterizing the Priabonian (SBZ 19-20). The revision of the literature, together with our own sample collections revealed that these new taxa occur in Priabonian rocks from different basins in the western Tethys. Virgasterocylina n. gen. also occurs in the Caribbean bioprovince in the middle and upper Eocene. In the western Tethys, Virgasterocylina ferrandezi is subdivided into two subspecies, V. f. ferrandezi (Ozcan and Less) and V. f. lessi n. ssp., which characterize the SBZ 19 and 20 biozones respectively.","PeriodicalId":49816,"journal":{"name":"Micropaleontology","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70447237","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Rotaliids are one of the groups of larger foraminifera that quickly recolonized the shallow-water environments after the mass extinction at the end of the Cretaceous. Here we present a summary of the state of the art about their stratigraphic distribution and diversity across the Paleocene and Eocene epochs. Our data suggest that their differentiation at the genus level was very rapid and reached its maximum in the upper Danian SBZ2. Specific diversification, instead, culminated in the upper Thanetian SBZ4, with a second peak during the Cuisian (=upper Ypresian). Successively, the rotaliid diversity definitely declined, whereas other groups of larger foraminifera, and especially Alveolina and Nummulites, became more widespread and flourished with a large amount of species, up to the lower Bartonian SBZ17, when a final drop in rotaliid diversity is recorded. These major changes appear strictly linked to climate warming events such as Late Danian Event (LDE, generic diversification of rotaliids), Paleocene-Eocene Thermal Maximum (PETM, faunal turnover followed by abrupt decrease in both generic and specific diversity), Early Eocene Climatic Optimum (EECO, increase in number of K-strategists under oligotrophic conditions) and Middle Eocene Climatic Optimum (MECO, ultimate drop in diversity and competition with other larger foraminifera).
{"title":"Rise and fall of rotaliid foraminifera across the Paleocene and Eocene times","authors":"A. Benedetti, C. A. Papazzoni","doi":"10.47894/mpal.68.2.02","DOIUrl":"https://doi.org/10.47894/mpal.68.2.02","url":null,"abstract":"Rotaliids are one of the groups of larger foraminifera that quickly recolonized the shallow-water environments after the mass extinction at the end of the Cretaceous. Here we present a summary of the state of the art about their stratigraphic distribution and diversity across the Paleocene and Eocene epochs. Our data suggest that their differentiation at the genus level was very rapid and reached its maximum in the upper Danian SBZ2. Specific diversification, instead, culminated in the upper Thanetian SBZ4, with a second peak during the Cuisian (=upper Ypresian). Successively, the rotaliid diversity definitely declined, whereas other groups of larger foraminifera, and especially Alveolina and Nummulites, became more widespread and flourished with a large amount of species, up to the lower Bartonian SBZ17, when a final drop in rotaliid diversity is recorded. These major changes appear strictly linked to climate warming events such as Late Danian Event (LDE, generic diversification of rotaliids), Paleocene-Eocene Thermal Maximum (PETM, faunal turnover followed by abrupt decrease in both generic and specific diversity), Early Eocene Climatic Optimum (EECO, increase in number of K-strategists under oligotrophic conditions) and Middle Eocene Climatic Optimum (MECO, ultimate drop in diversity and competition with other larger foraminifera).","PeriodicalId":49816,"journal":{"name":"Micropaleontology","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70446323","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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