Smaller Foraminifers Research Articles

Permian reef and shelf carbonates of the Arabian platform and Neo-Tethys as recorders of climatic and oceanographic changes

Abstract The present study provides an example of how Permian benthic carbonate production is controlled by oceanographic factors and climate. After the Permo-Carboniferous glaciation, shallow-marine benthic carbonate production exhibits strikingly different temporal and spatial patterns on the eastern Arabian plate and on isolated platforms of the SW Neo-Tethys. Close to the SE margin of the Arabian plate in the Haushi area, Cisuralian (late Sakmarian-early Artinskian) mixed carbonate-siliciclastic deposits of the Saiwan Formation and Guadalupian (Wordian) marl-carbonate alterations of the Khuff Formation are characterized by dominance of crinoids, brachiopods, bivalves and bryozoans. Scarcity of calcareous algae and zooxanthellate invertebrates indicate that members of the heterozoan association (bryonoderm facies) were responsible for carbonate production. Guadalupian carbonates of the Khuff Formation in the Haushi area show striking compositional differences to lateral equivalents in the subsurface where photozoan carbonates dominate. Contemporaneous carbonates of the Saiq Formation from the Saih Hatat (Oman Mountains) exhibit a twofold composition: siliciclastic sediments contain small tabulate corals of the heterozoan association. Most of the formation is carbonate of the photozoan association with fusulinaceans, smaller foraminifers, calcareous algae, rugose corals and aggregate grains. Lopingian carbonates of the Saiq Formation (Saih Hatat) are dominated by heterozoan carbonate production with crinoids, chaetetids, bryozoans and brachiopods, and resemble heterozoan bryonoderm carbonates. Shallow-water reef carbonates of the Neo-Tethys, preserved as blocks in the Ba'id area (Oman Mountains) and the Batain coast, are contrasting: in the Ba'id area Late Cisuralian-Early Lopingian blocks of photozoan carbonates have been found, containing calcareous sponges, rugose corals, richthofeniid brachiopods and calcareous algae. Cisuralian blocks from the Batain coast are very similar to the heterozoan bryonoderm facies, while Guadalupian reef blocks show striking similarities to photozoan chlorosponge associations. Combining climate modelling data with outcrop data, dominance of heterozoan carbonate production along the rim of Arabian plate and the Neo-Tethys can be explained by cool water during the Cisuralian and local upweUing of nutrient-rich water during the Guadalupian. Formation of Lopingian heterozoan carbonates of the Saiq Formation is least understood but could be the consequence of upwelling of saline and nutrient-rich oceanic bottom water. Comparing the ecological complexity of reefs, chlorosponge reefs built complex frameworks with a variety of ecological niches, if encrusters are present, whereas heterozoan reef communities are comparatively simple in their structure.

Middle Permian (Late Guadalupian) foraminifers from Dark Canyon, Guadalupe Mountains, New Mexico

Research Article| January 01, 2006 Middle Permian (Late Guadalupian) foraminifers from Dark Canyon, Guadalupe Mountains, New Mexico Galina P. Nestell; Galina P. Nestell Department of Earth and Environmental Sciences, University of Texas at Arlington, Arlington, TX 76019, USA, email: gnestell@uta.edu; nestell@uta.edu Search for other works by this author on: GSW Google Scholar Merlynd K. Nestell Merlynd K. Nestell Department of Earth and Environmental Sciences, University of Texas at Arlington, Arlington, TX 76019, USA, email: gnestell@uta.edu; nestell@uta.edu Search for other works by this author on: GSW Google Scholar Author and Article Information Galina P. Nestell Department of Earth and Environmental Sciences, University of Texas at Arlington, Arlington, TX 76019, USA, email: gnestell@uta.edu; nestell@uta.edu Merlynd K. Nestell Department of Earth and Environmental Sciences, University of Texas at Arlington, Arlington, TX 76019, USA, email: gnestell@uta.edu; nestell@uta.edu Publisher: Micropaleontology Press Received: 11 Nov 2005 Accepted: 25 Jan 2006 First Online: 09 Mar 2017 Online ISSN: 0026-2803 Print ISSN: 1937-2795 © 2005 The Micropaleontology Project, Inc. Micropaleontology (2006) 52 (1): 1–50. https://doi.org/10.2113/gsmicropal.52.1.1 Article history Received: 11 Nov 2005 Accepted: 25 Jan 2006 First Online: 09 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Galina P. Nestell, Merlynd K. Nestell; Middle Permian (Late Guadalupian) foraminifers from Dark Canyon, Guadalupe Mountains, New Mexico. Micropaleontology 2006;; 52 (1): 1–50. doi: https://doi.org/10.2113/gsmicropal.52.1.1 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyMicropaleontology Search Advanced Search Abstract Late Capitanian foraminifers are described from two cores taken by Amoco on the north side of the entrance of Dark Canyon. The Amoco #1 core (400ft) penetrates proximal forereef debris of the Tansill Formation and bottoms in massive Capitan reefal limestone. The Amoco #2 core (468ft) penetrates proximal backreef lagoonal deposits of the upper Yates Formation and the Tansill Formation.Foraminifers are very diverse and abundant in these cores. Based on the fusulinid distribution, the Codonofusiella extensa (upper part of the Yates Formation), Yabeina texana, Paradoxiella pratti and Reichelina lamarensis zones (lower and middle Tansill Formation) are present in the Amoco #2 core. Among small foraminifers, the first appearance of the genera Sengoerina and Crescentia are recorded at the base of the Y. texana Zone and they disappear at the top of the P. pratti Zone. The genus Baisalina appears at the base of the R. lamarensis Zone and disappears at the top of that zone. The Ocotillo Silt Member and upper dolomitized part of the Tansill Formation do not contain foraminifers. The Ocotillo Silt Member is present in the Amoco #2 core at a depth of from 88 to 112ft and, because of its regional dip of approximately six degrees, would possibly project below the base of the Amoco #1 core, thus correlating the Capitan and Tansill formations in the Amoco #1 core with the upper Tansill Formation of the Amoco #2 core. The lower part of the Amoco #1 core (from 110 to 370ft) contains fusulinacean species of the Paraboultonia splendens Zone. The assemblage of small foraminifers is dominated by species of nodosariids and hemigordiopsids. Four new genera and sixteen new species of foraminifers are described from both cores. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

Do inverted depositional sequences and allochthonous foraminifers in sediments along the Coast of Kachchh, NW India, indicate palaeostorm and/or tsunami effects?

The study of 134 subsurface sediment samples from three cores collected along the Coast of Kachchh, off Gujarat Province, NW India, shows the presence of 151 foraminifer species. Q-mode cluster analysis on foraminifer data for each core and radiocarbon dating at ten different downcore depths reveal an inverted sequence, with fine-grained sediments and small foraminifers sandwiched between normal detrital sediments at water depths of 10–20 m. It is postulated that ∼8,000 years B.P., sediments ranging in age from ∼10,000 to ∼12,000 years B.P. were eroded from deeper offshore deposits by storm/tsunami(s), and were subsequently transported and redeposited in shallow regions, resulting in an inverted sequence, followed by a normal detrital sequence deposited between ∼8,000 and ∼7,000 years B.P. A second, similar event resulted in the deposition of ∼10,000 year old sediments over a normally deposited, ∼7,000 year old sequence. The second inverted sequence was subsequently overlain by a normal sequence. It is hypothesised that the erosion and transportation of fine-grained sediments from deeper water, and their deposition in shallower water against the rule of gravity, are the result of storm/tsunami influence.

Integrated biostratigraphy of foraminifers, radiolarians and conodonts in shallow and deep water Middle Permian (Capitanian) deposits of the "Rader slide", Guadalupe Mountains, West Texas

A diverse assemblage of microfossils is present in a 6m thick sequence of three debris flow deposits interbedded with thin turbidite limestone beds and fine grained siliciclastics exposed above the megaconglomerate in a section (known as the “Rader Slide" in numerous guidebook stops) of the Rader Limestone Member of the Bell Canyon Formation of Capitanian age (Middle Permian) in the Guadalupe Mountains of West Texas. Each debris flow, derived from nearby Capitan Reef shelf-margin and slope deposits, contains a distinct microfossil assemblage. Small foraminifers and fusulinaceans, conodonts, radiolarians, sponge spicules, fish dermal plates and teeth, and other fragmental fossils are present in this sequence. Conodonts are relatively scarce in the first (or lowest) debris flow, except in its upper part, but they are common to abundant in the other two debris flows, and very abundant in several of the thin turbidite limestone beds. All of the conodonts present appear to be morphotypes of one population of the species Jinogondolella postserrata, except for one new conodont species, and the Jinogondolella postserrata Zone is clearly documented in this sequence. The debris flows contain the fusulinaceans Rauserella, rare Codonofusiella, Polydiexodina, Leella? and various species of the small foraminifers Globivalvulina, Hemigordius, Baisalina, Abadehella, Deckerella, Neoendothyranella, Vachardella, Geinitzina, and Polarisella. Some of the thin turbidite limestone beds contain a foraminiferal assemblage similar to that found in the debris flows, but with lower diversity. Many small foraminiferal species appear to be endemic, although a few are closely related to species known in Permian age strata in Italy, Greenland, the Russian Far East, northeastern part of Russia (Omolon massif), and the Zechstein of Germany and the Baltic area. Two thin limestone beds above the second debris flow contain primarily radiolarian species known from the Follicucullus japonicus Zone of Japan. Nine new species of small foraminifers (Bisphaera? improvisa, Vissariotaxis? nativus, Multidiscus raderensis, Baisalina miscella, Agathammina minuscula, Polarisella globosa, Geinitzina jucunda, Robustopachyphloia texana and Spireitlina capitanensis) and one new conodont species Jinogondolella gladirobusta are described.

CARBONIFEROUS-PERMIAN STRATIGRAPHY AND FUSULINIDS OF EASTERNIRAN. THE PERMIAN IN THE BAG-E-VANG SECTION (SHIRGESHT AREA)

The Jamal Formation of the Bag-e-Vang section near Shirgesht is described. The lower part of the formation (Bag-e-Vang Member) is composed of shales and marls with interbeds of hallow water bioclastic limestones. It contains abundant fusulinids indicative of the uppermost Yakhtashian-basal Kubergandian. The upper part of the Jamal Formation is represented by micritic and finely detrital limestones and dolomites. The age of this part of the formation is based on rare fusulinids and smaller foraminifers and cannot be defined more precisely than the Kubergandian-Dorashamian of the Upper Permian. The formation has visible conformable contacts with the underlying Sardar and overlying Sorkh Shale Formations. However, there may be unobservable stratigraphic hiatuses of indefinite scope at the formation boundaries. Forty-one species and subspecies, which belong to 27 genera and subgenera and 9 families of fusulinids, were identified in the Permian of the section described. Among them, two genera ( Iranella, Paraleeina ), one subgenus ( Cuniculina ) and 8 species, i. e. Yangchienia compressaeformis,Paradoxiella insueta, Darvasites minutus, Skinnerella chusenellaeformis, Iranella bella, I. longa, I. orbiculata, and I. pauca, are new.

Stratigraphie, paléoécologie et foraminifères du paléogène des Alpes Maritimes et des Alpes de Haute-Provence (Sud-Est de la France)

Paleogene sedimentation in the Alpes Maritimes and Alpes de Haute Provence regions is composed of one complete sedimentary sequence. This sequence begins with the continental Formation from Microcodium and continues with the Cerithium layers, the Calcaires Nummulitiques and the Marnes Bleues, which are overlaid by the turbidites of the Gres d’Annot Formation. Sedimentation starts in the Nummulites perforatus zone close to the base of ‘the Truncorotaloides rohri zone (P 14) and ends in the Cassigerinella chipolensis–Pseudohastigerina micra zone (P 18) and the NP21 zone in the upper part of the Gres d’Annot. More biomarkers were used in order to define a more detailed local biozonation (biozones AMP 1 to AMP 7). Four local zones were also defined by the last occurrence of Nummulites millecaput and N. perforatus–N. ptukhiani and then by the first appearance of N. retiatus (AMGF 1–4). The evolution of benthic foraminiferal assemblages shows an increase in bathymetry from the internal platform in the Cerithium layers to the calcareous platform with large foraminifers, then to the external platform and the deep offshore environment of the Marnes Bleues and Gres d’Annot. Low faunal diversity in the Gres d’Annot together with the predominance of agglutinated species indicates a poorly oxygenated, organic rich and turbidite environment. Seven steps (SD 1 to SD 7) in the Eocene marine transgression are shown from East to West by detailed local biozonation and sequence analysis. Gres d’Annot sedimentation is also diachronous, beginning within the Truncorotaloides rohri zone (P 14, AMP 1) in the East and ending within the Pararotalia opima opima zone (P 20, middle Rupelian) in the West (Barreme). Small foraminifer Paleogene fauna from the Alpes Maritimes and Alpes de Haute Provence was studied from 400 samples. It is composed of 378 species. Two new taxa are proposed: Fissurina niceana n. sp. and Globocassidulina alpina n. sp. The species from the Escarene and Gorbio neighborhood described by M. von Hantken (1884) were re-examined.

FORAMINIFERA, ALGAE AND CARBONATE MICROPROBLEMATICA FROM THE LATE WUCHIAPINGIAN/DZHULFIAN (LATE PERMIAN) OF PELOPONNESUS (GREECE)

The origin of late Permian olistoliths found in the Glypia Cenozoic flysch must be seeked in regions located to the east of the Parnon Mountain and in units that were more internal to Pindos Unit, especially in the islets of Karavia in the Argolis Gulf, and the Episkopi Formation in Hydra Island, that display probably the largest outcrops of this age. The most interesting olistolith is a bioclastic grainstone. It yields about forty taxa of algae, microproblematica, smaller foraminifers and fusulinids, that are briefly described. Three markers generally not co-occurring are locally associated: Paradunbarula ( Shindella ) shindensis , Hemigordiopsis cf. luquensis and Colaniella aff. minima . The age of the Paradunbarula ( Shindella ) biozone is most probably late Wuchiapingian/Dzhulfian, although other datings have been proposed from late Capitanian to late Changhsingian. Due to this dating of the Shindella zone, the coexistence of the first Colaniella with the last Hemigordiopsis are not late Capitanian/Midian in age, but late Wuchiapingian. The similarities of the Greek microfauna with that of South China and southeastern Pamirs, are incompatible with a larger Paleotethys but support the paleogeographic reconstructions which indicate a close location of these geographic units (Pangea B).

MICROFACIES AND MICROFOSSIL ASSEMBLAGES (SMALLER FORAMINIFERS, ALGAE, PSEUDOALGAE) OF THE HUECO GROUP AND LABORCITA FORMATION (UPPER PENNSYLVANIAN-LOWER PERMIAN) SOUTH-CENTRAL NEW MEXICO, USA

During the latest Carboniferous and earliest Permian (Virgilian-Wolfcampian), the eastern margin of the Orogrande Basin in south-central New Mexico was rimmed by a narrow, tectonically unstable shelf, on which sediments of the Laborcita and Abo formations were deposited. Sediments of the Hueco Group accumulated on the more stable western margin of the Orogrande Basin. On the eastern shelf, the Laborcita Formation of the northern Sacramento Mountains represents a transition from marine to terrestrial facies and is composed of clastic-carbonate cycles. Limestones accumulated during relative sea-level highstands in a shallow marine shelf environment. Clastic sediments were deposited during relative lowstands when there was strong clastic influx in a nearshore to terrestrial environment. The overlying Abo Formation is composed of terrestrial red beds. On the western shelf, the Shalem Colony Formation of the Hueco Group, equivalent to the Laborcita Formation, is composed of mostly normal marine shallow shelf limestones with only minor interbedded clastics. The Robledo Mountains Formation and Hueco Group reflects a trend from a restricted shallow shelf and tidal flat clastics facies in the lower part to more open conditions in the upper part, which also prevailed during deposition of the overlying Apache Dam Formation. Limestones of the Laborcita Formation and Hueco Group contain smaller foraminifers, algae and problematic carbonate microfossils. All taxa except two pseudoalgae in open nomenclature ( Litostroma (?) sp. and “problematicum gen. 1”) are taxa already described. Compared with the Carnic Alps (Austria/Italy), the assemblages of smaller foraminifers of the Laborcita Formation and Shalem Colony Formation are very similar to those of the Auernig and Carnizza Formations (Auernig Group), and Lower Pseudoschwagerina Limestone (Rattendorf Group), indicating an Orenbugian (“Bursumian”) to Asselian age. Smaller foraminifers of the Robledo Mountains Formation allow correlation with the Grenzland Formation and Upper Pseudoschwagerina Limestone (Rattendorf Group) of the Carnic Alps, dated as Asselian to Sakmarian. Smaller foraminifers of the Apache Dam Formation suggest an Artinskian age, correlating with the Wolfcampian, or the Trogkofel Group of the Carnic Alps.

FLORESINA: A GENUS OF PREDATORS, PARASITES OR SCAVENGERS?

Hallock and Talge (1994) described a small predatory foraminifer Floresina amphiphaga attacking the larger foraminifer Amphistegina gibbosa . The attack by F. amphiphaga on A. gibbosa often resulted in the death of the latter and formed a characteristic trace on its test. We report a similar trace on the test of the planktonic foraminifer, Globorotalia menardii , from a sample from 175 m water depth, collected seaward of the barrier reef at Suva, Fiji, that may be the result of Floresina attack. If this supposition is correct, it suggests that drilling is more widespread in the genus that previously known; that the phenomenon may extend beyond alleged predation or parasitism of living foraminifera to scavenging on dead foraminifera; and that foraminfer-foraminifer interactions involving drilling may be more widespread than previously suspected.

The Permian–Triassic boundary in central East Greenland: past and present views

The latest Permian, Changhsingian fauna in East Greenland is a typical northern cool-water fauna, dominated by a low diversity assemblage of boreal brachiopods and lacking fusulinids, small foraminifers and fish. Continuous sedimentation across the Permian–Triassic boundary is recorded at the Fiskegrav locality, southwestern Jameson Land but the precise location of the boundary is disputable within an interval covering the uppermost few metres of the Schuchert Dal Formation and the lowermost 23.5 m of the Wordie Creek Formation. Based on palynological data the boundary is best placed 50 cm below the top of the Schuchert Dal Formation at Fiskegrav, in a monotonous interval of bioturbated, grey offshore marine siltstone characterised by a marked drop in the ä13C of organic carbon. ä13C of carbonate from brachiopods shows a temporary drop of 2‰, 4–5 m below the top of the Schuchert Dal Formation, while the ä13C of whole rock carbonate reaches a minimum in the lowermost part of the Wordie Creek Formation. Comparisons to the ä13C carbonate curves from the boundary stratotype section at Meishan, China are therefore highly subjective and allow the boundary to be placed within a 24–27 m thick interval in the topmost Schuchert Dal Formation and the lowermost Wordie Creek Formation, – here termed as the Permian–Triassic boundary interval. The lower part of this interval, below the palynological boundary includes a low diversity Permian-type fauna of two brachiopod and four agglutinated foraminifer genera. Above the palynological boundary, in the uppermost 50 cm of the Schuchert Dal Formation remains of the Triassic-type fish Bobasatrania occur together with agglutinated foraminifers, and at the base of the Wordie Creek Formation a more diverse, Triassic-type fish fauna with five genera is present. In the stratotype section at Meishan the first Triassic-type faunal elements appear above the negative ä13C anomaly in what is regarded as a topmost Permian mixed fauna interval. A similar situation may possibly exist in East Greenland so the old East Greenland issue of faunal mixing with Permian-type fauna in the Triassic may turn out to be a matter of having Triassic faunal elements in the Permian.

Internal structure and depositional environment of Late Carboniferous mounds from the San Emiliano Formation, Cármenes Syncline, Cantabrian Mountains, Northern Spain

Well-exposed mounds are common in limestone of the Late Carboniferous San Emiliano Formation, Cantabrian Mountains (Northern Spain). They occur as obvious primary topographic features. Careful study of the mound intervals and surrounding strata revealed the internal structures of mounds and the factors controlling their growth. The substrate (2 – 3 m) of the mounds consists of greyish to reddish, bedded oolitic and oncolithic packstone and grainstone. Crinoids, fragments of the alga Epimastopora, and, rarely, bryozoans are present. Ooids and oncoids indicate a wave-dominated high-energy environment. Presence of quartz indicates the influence of terrigenous siliciclastic input. Mound intervals (6 – 12 m thick) are characterized by skeletal – microbial boundstone. Donezellid algae, agglutinated worm tubes, and calcisponges are the dominant fossils. Smaller foraminifers, gastropods, and brachiopods are also present. A peloidal-clotted matrix is characteristic and accounts for more than 30% of the mound volume. Intraframe pores are mainly filled by peloidal sediment and early marine cement. Intermound strata are approximately one-third as thick as time equivalent mounds. Mound fossils (algae, agglutinated worm tubes, and sponges) are uncommon. However, intermound strata are generally more diverse than the mounds, containing fusulinids, smaller foraminifers, bryozoans, gastropods, crinoids, and bioclasts. Some of these fossils have micritic envelopes. Bedded packstone and grainstone, 3 – 6 m thick, with siliciclastic debris, rugose corals, and chaetetid sponges characterize the capping facies. Coated grains and small ooids are uncommon. This facies indicates shallowing to a higher energy environment and/or a higher input of siliciclastics, inhibiting mound growth. Mounds are interpreted to have accreted in a quiet environment below wave base. This position is comparable to the depositional environment inferred for many Late Paleozoic mounds described elsewhere, e.g., from Texas and New Mexico, Canadian Archipelago, and Carnic Alps in Austria. Mound relief is explained by (1) accumulation of peloidal-clotted sediments limited to boundstone and probably related to microbial activities, (2) widespread marine cementation within this area, and (3) low export of mound fossils to intermound areas. The position of the mounds within the sequence, and their initiation, size and termination, seem to be mainly controlled by sea-level fluctuations and siliciclastic input. D 2001 Elsevier Science B.V. All rights reserved.

SMALLER FORAMINIFERS OF THE UPPER CARBONIFEROUS AUERNIG GROUP, CARNIC ALPS (AUSTRIA/ITALY)

The micropaleontological components, particularly smaller foraminifers, from limestonesof theUpper Carboniferous Auernig Group (Carnic Alps, Austria/Italy) are described. Most of the taxa have been previously recorded from North America, Arctica and Russia (Urals, Donbass). The biostratigraphical value of Pseudovidalina , Nodosinelloides , Tezaquina and Vervilleina for the Oembourgian stage is recognized. The systematical part is principally devoted to generic discussion concerning Hemidiscus and Eolasiodiscus ; Palaeobigenerina , Deckerella , Cribrogenerina and Climacammina ; Ammovertella , Calcivertella and Calcitornella ; Spireitlina and Pseudopaleospiroplectammina ; Pseudovidalina and Raphconilia : Vervilleina and Tezaquina ; and Nodosinelloides , Protonodosaria and Nodosaria .

SMALLER FORAMINIFERS, CHARACTERISTIC ALGAE AND PSEUDO-ALGAE OF THE LATEST CARBONIFEROUS-EARLY PERMIAN RATTENDORF GROUP,CARNIC ALPS (AUSTRIA/ITALY)

Limestones of the latest Carboniferous-early Permian Rattendorf Group (Lower Pseudoschwagerina Limestone, Grenzland Formation and Upper Pseudoschwagerina Limestone) of the Carnic Alps (Austria/Italy) contain a rich and interesting assemblage of smaller foraminifers, algae and pseudo-algae. The foraminiferal assemblage of the Lower Pseudoschwagerina Limestone is identical to that of the Auernig Formation. The Grenzland Formation is characterized by the appearance of the genus Geinitzina and Pseudovermiporella, and the disappearance of Bradyinidae. The Upper Pseudoschwagerina Limestone contains the same species as the Grenzland Formation, but is characterized by the local appearance of Neoendothyra (?) and diverse species of Hemigordiidae and Nodosarioidea. The biostratigraphical value of diverse species of Hemigordius, iA renovidalinai sensu Baryshnikov = iNeohemigordiusi sensu Pinard & Mamet, Nodosinelloides , Protonodosaria and Geinitzina for the Asselian and early Sakmarian stages is briefly discussed. The systematical part contains some generic remarks on the Hemigordiidae and Nodosarioidea. Due to the porcelaneous wall, the microfossils Ellesmerellapermica (Pia) (= iGirvanellai subparallela Flugel & Flugel-Kahler) and Pseudovermiporella spp., which are generally interpreted as algae, are considered as attached miliolinid foraminifera. A new genus of problematical Chlorophyta, Homannisiphon, is established.

Late Changhsingian foraminifers of the northwestern Caucasus

Other| July 01, 2001 Late Changhsingian foraminifers of the northwestern Caucasus Galina P. Pronina-Nestell; Galina P. Pronina-Nestell University of Texas at Arlington, Department of Geology, Arlington, TX, United States Search for other works by this author on: GSW Google Scholar Merlynd K. Nestell Merlynd K. Nestell Search for other works by this author on: GSW Google Scholar Author and Article Information Galina P. Pronina-Nestell University of Texas at Arlington, Department of Geology, Arlington, TX, United States Merlynd K. Nestell Publisher: Micropaleontology Press First Online: 03 Mar 2017 Online ISSN: 0026-2803 Print ISSN: 1937-2795 GeoRef, Copyright 2004, American Geological Institute. Micropaleontology (2001) 47 (3): 205–234. https://doi.org/10.2113/47.3.205 Article history First Online: 03 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Galina P. Pronina-Nestell, Merlynd K. Nestell; Late Changhsingian foraminifers of the northwestern Caucasus. Micropaleontology 2001;; 47 (3): 205–234. doi: https://doi.org/10.2113/47.3.205 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyMicropaleontology Search Advanced Search Abstract Small foraminifers and fusulinaceans from Upper Permian strata in the Bolshaya and Malaya Laba, and Belaya river basins in the Peredovoy Range of the Northwestern Caucasus have been restudied. New age data show that they are clearly Late Changhsingian in age. The foraminifers occur in rocks in isolated outcrops that include bedded limestone, biohermal buildups, and terrigenous clastics. Many foraminiferal species previously described by K. Miklukho-Maklay in 1954 are here revised and redescribed based on specimens from some of the same sections. Nine new species and two new genera of small foraminifers are described. The foraminifer assemblage is correlated with similar coeval associations in South China, the South Primorye, Pamirs, and Transcaucasia. This content is PDF only. Please click on the PDF icon to access. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

JINZHANGIA, A NEW STAFFELLID FUSULINOIDEA FROM THE MIDDLE PERMIAN DAAOZI FORMATION OF THE BAOSHAN BLOCK, WEST YUNNAN, CHINA

Permian foraminifers are reported and illustrated for the first time from the lower part of the Daaozi Formation of the Baoshan Block, West Yunnan, China. The Baoshan Block is a Gondwana-derived continental fragment that is believed to be a key to understanding Gondwana dispersion and Asian accretion during Paleozoic and Mesozoic time. Its Late Paleozoic foraminifers have been poorly documented until now. The Daaozi assemblage is dominated by oval staffellids representing the new genus, Jinzhangia, with J. shengi Ueno, n. sp. as the type species, and several other smaller foraminifers, including Pachyphloia robustaformis Wang, Okimuraites ? cf. O. guvenci (Altiner), and Kamurana ? sp. Although these foraminifers do not provide a precise age determination, associated corals reveal a Murgabian age for the assemblage. Among the oval and fusiform staffellids from Eurasia, only Leella armenica Rozovskaya from the Middle Permian of Transcaucasia should be referable to the new genus Jinzhangia. Thus, Jinzhangia apparently is restricted to Baoshan and Transcaucasia, which are parts of the Cimmerian continent and which was paleogeo-graphically independent of both Gondwanaland and the Cathaysian blocks, such as Indochina and Yangtze, during Permian and Triassic time.

Marine carbonate facies in response to climate and nutrient level: The upper carboniferous and permian of central spitsbergen (Svalbard)

Carbonate-dominated successions of the Gipsdalen and Tempelfjorden Groups from Svalbard record a significant shift from Photozoan to Heterozoan particle associations in neritic settings during the late Palaeozoic. During the Bashkirian, benthic particle associations which included photoautotrophs such as phylloid algae (Chloroforam Association) characterised shallow subtidal environments. Most depositional settings which endured siliciclastic terrestrial input exhibited poorly diversified associations dominated by brachiopods, bryozoans and siliceous sponges (Bryonoderm Association). During the Moscovian to Asselian, highly diversified associations typified by various calcareous green algae,Palaeoaplysina, Tubiphytes, fusulinids, smaller and encrusting foraminifers (Chloroforam Association) prevailed in carbonate sediments from supratidal to shallow subtidal environments. During the Sakmarian and Early Artinskian, oolitic carbonate sands (Chloroforam Association) typified intertidal flats, whereas shallow subtidal environments were occupied by moderately diversified associations with fusulinids, smaller foraminifers, echinoderms and bryozoans (Bryonoderm-extended Association) and poorly diversified associations with echinoderms, brachiopods and bryozoans (Bryonoderm Association). During the Late Artinskian to Kazanian, poorly diversified associations characterised by brachiopods, echinoderms and bryozoans (Bryonoderm Association), and sponge-dominated associations (Hyalosponge Association) reigned within siliceous carbonates of intertidal and shallow subtidal environments.

EARLIEST ARTINSKIAN (EARLY PERMIAN) FUSULINIDS REWORKED IN THE TRIASSIC LERCARA FORMATION (NW SICILY)

The Permian limestone boulders reworked in the Triassic Lercara Formation (NW Sicily) contain carbonate microfossils consisting of algae, smaller foraminifers and fusulinids. The following fusulinids are described: Quasificsulina ultima Kanmera, Robustoschwagerina cf, R, schellwieni (Hanzawa), Chalaroschwagerina (?) globosa (Schellwien). The group of Chalaroschwagerina (?) vulgaris (Schellwien) is emended. Based on this fusulinid assemblage, the limestone boulders of Lercara are age-dated as early Yakhtashian; i.e,, earliest Artinskian (circa -280 to -275 Ma). Therefore at least two distinct olistostromes are present in Sicily: the post-Yakhtashian olistostrome studied here, and the second one post-Dorashamian in age. Similar assemblages do not occur in adjacent European areas (Camic Alps, Montenegro or Greece), but they have been recorded in Darvas (North Pamir) and Japan, revealing constant paleoecological conditions throughout the Paleotethys.

The permian sequence reconstructed from reworked carbonate clasts in the Batain Plain (northeastern Oman)

An almost complete Permian sequence is reworked in the conglomerates and sandstones of the Aseelah Unit forming the lower part of the Batain Croup. This series of Late Permian to Earliest Triassic age overlies conformably the Qarari Unit, dated as Middle Permian by ammonoids. The bioclastic limestone pebbles and boulders deposited on shallow marine-shelf environments yield diversified assemblages of dasyclads, red algae, fusulinids and smaller foraminifers, indicating Yakhtashian, Bolorian, Kubergandian, Early Murgabian, Midian and Dzhulfian ages (systematic work in progress).

Subtropical carbonates in a temperate realm; modern sediments on the Southwest Australian shelf

The southwestern continental margin of Australia (19 degrees S-22 degrees S) in the western Indian Ocean is transitional between cool-water and warm-water carbonate realms. It comprises the incipiently rimmed, flat-topped, steep-fronted Rottnest Shelf in the south, the uniform subtropical starved Carnarvon Ramp off Shark Bay, and the Ningaloo fringing reef in the north. The margin is strongly influenced by the poleward-flowing, warm, nutrient-poor Leeuwin Current, which promotes overall downwelling and strong summer equatorward-blowing winds, which generate local seasonal upwelling. The structurally quiescent northern part of the Rottnest Shelf, with minimum accommodation, is characterized by luxuriant stands of sea-grasses and macrophytes growing on coralline-encrusted hardgrounds and rooted in sediments rich in coralline algae and larger, symbiont-bearing foraminifers together with abundant cool-water elements such as bryozoans, molluscs, and small foraminifers. Halimeda is poorly calcified and does not contribute to the sediment. Azooxanthellate corals, although present, are not common. Such a sediment pattern has many analogs in the geologic record, especially the early Cenozoic. The incipient rim is a morphologically complex linear ridge system interpreted to be a buried mid-Pleistocene barrier reef or beach-dune complex. The northern part of the ridge complex is capped by the Houtman Abrolhos reef platforms. Subphotic sediments on the deep, outer shelf and upper slope, affected by seasonal upwelling, are typical cool-water, poorly sorted, bryozoan-dominated deposits rich in small foraminifers and sponge spicules. The inner part of the more structurally active Carnarvon Ramp ranges from steep eolianite cliffs to hypersaline environments of Shark Bay to the Ningaloo fringing reef. Mid-ramp sediment, especially off Shark Bay, is mostly relict or stranded and foraminifer-dominated sand with abundant Mg-calcite-cemented intraclasts. These sediments, accumulating on a relatively barren seafloor, likely represent attenuated carbonate production brought about by downwelling and episodic incursions of saline, Shark Bay-derived waters onto the ramp. The outer ramp is either planktic foraminiferal sand, sorted by strong bottom currents, or spiculitic mud. Such sedimentation patterns should typify the western margins of large ocean basins during those periods in geologic history when circumglobal equatorial circulation was active, and equatorial gateways narrow, in contrast to eras of supercontinents, when cool-water carbonate sedimentation and upwelling prevailed in similar settings. Furthermore, because low-latitude trade winds relax during glacial epochs and the cool-water, upwelling belt moves equatorward into otherwise tropical realms, temperate and subtropical sedimentation patterns in these regions should oscillate at the 100 ky scale in the stratigraphic record.

Middle Permian (Murgabian) fusuline faunas, Torlesse Terrane, New Zealand

Two disparate fusuline limestone localities are known from Torlesse Supergroup rocks of Canterbury in the South Island of New Zealand. Fossils at one of these localities (J35/fl9, Glenfalloch Stream) are well preserved. New thin‐section study establishes the presence of a low‐diversity foraminiferan fauna dominated by the fusuline Parafusulina (Skinnerelld) japonica. At least three fusuline taxa are recognised including Parafusulina {Skinnerelld) cuniculata (Igo 1967), and two new subspecies described herein: Parafusulina (Skinnerelld) japonica deprati nov. subsp. and Parafusulina (Skinnerelld) japonica curta nov. subsp. Four species of small foraminifers are also recognised. Overall, the fauna correlates best with late Middle Permian sequences of Tethyan affinity in Eurasia, and specifically with those of the Murgabian Stage (probably early Murgabian). Fossils at the second locality (I39/f8666, Te Akatarawa Stream) are poorly preserved but nevertheless appear to indicate a comparable faunal composition and age range of late Kubergandian to early Murgabian.