Temat: frasnian - Prolib Integro

Skocz do pozycji: 1.

Tytuł:: Ostracods and facies of the Early and Middle Frasnian at Devils Gate in Nevada: Relationship to the Alamo Event
Autorzy:: Casier, J -G
Berra, I.
Olempska, E.
Sandberg, C.
Preat, A.
Tematy:: ostracod
Early Frasnian
Frasnian
Middle Frasnian
Nevada
relationship
Alamo Event
Ostracoda
conodont
sedimentology
paleoecology; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Paleobiologii PAN
Powiązania:: https://bibliotekanauki.pl/articles/23394.pdf Link otwiera się w nowym oknie
Opis:: In order to document the Alamo Event and to investigate its influence on shallow−marine environments, we undertook a study of ostracods, conodonts, and analysis of the sedimentology of the lower member of the type Devils Gate Limestone. Six major carbonate microfacies (MF1–MF6) ranging from open−marine environments below storm wave base to pre−evaporitic supratidal lagoons were recognized. The sedimentological study detected no important sedimentological changes during the Alamo Event; only an influx of detrital material and lithoclasts indicate that an unusual event had occurred. Ostracods are generally rare or absent in the lower member of the Devils Gate Limestone, and only 2,000 carapaces, valves and fragments were extracted; from these some 26 taxa were identified. Two new species, Voronina? eureka and Serenida dorsoplicata are proposed. The ostracods belong to the Eifelian Mega−Assemblage and their distribution was influenced by strong salinity variations. Because of the rarity and low diversity of ostracods and conodonts in samples collected from the lower part of the lower member of the Devils Gate Limestone it is not adequate to demonstrate conclusively an extinction event close to the Alamo Event Bed. Nevertheless the greater abundance and diversity of ostracods above this bed seems to indicate that the Alamo Event did not result in significant extinction of ostracod taxa in this shallow water setting. The ostracod fauna present in the lower member of the Devils Gate Limestone suggests faunal exchanges between Nevada and the Russian Platform via the Western Canadian platform.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Early-Middle Frasnian transition: Biotic response to a major perturbation of the global carbon budget
Autorzy:: Balinski, A
Olempska, E.
Racki, G.
Tematy:: Early-Middle Frasnian
Frasnian
biotic response
perturbation
global carbon budget; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Paleobiologii PAN
Powiązania:: https://bibliotekanauki.pl/articles/22463.pdf Link otwiera się w nowym oknie
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Early and Middle Frasnian brachiopod faunas and turnover on the South China shelf
Autorzy:: Ma, X -P
Becker, R.T.
Li, H.
Sun, Y.-Y.
Tematy:: Early Frasnian
Middle Frasnian
Frasnian
paleontology
brachiopod fauna
South China shelf
Devonian
Brachiopoda
Cyrtospirifer
faunal turnover; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Paleobiologii PAN
Powiązania:: https://bibliotekanauki.pl/articles/21029.pdf Link otwiera się w nowym oknie
Opis:: The first appearance of the brachiopod Cyrtospirifer and related forms in the Late Devonian of South China significantly postdates the beginning of the Frasnian and the entry of the group in other parts of the world. Scattered data from different sections suggest that its first entry, associated with the emergence of other plicate spiriferids, such as theodossid and conispiriferid brachiopods, was late in the Middle Frasnian. At the same time, many rhynchonellids disappeared or became extinct locally in South China. This brachiopod faunal overturn near the Palmatolepis punctata–Early Pa. hassi zonal boundary is the most significant event in the Early–Middle Frasnian of South China, characterized by about a 35% loss of existing species and the flourishing of the plicate spiriferids, which was coeval with the end of a major biogeochemical perturbation recently recognized in the Pa. punctata Zone. By contrast, atrypid brachiopods do not seem to show any significant diversity change. The brachiopod faunal change was probably related to a (local?) transgressive event in South China, which also brought new pelagic faunas northwards into some intra−shelf deeper water areas, such as the Shetianqiao area in central Hunan Province. Fifteen brachiopod species are described and illustrated, which include some taxa that are first recorded or recognized in South China, e.g., the spiriferid Pyramidaspirifer, which is now known from both North America and South China. One new species, Desquamatia qiziqiaoensis, is erected.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Early-Middle Frasnian cyrtospiriferid brachiopods from the East European Platform
Autorzy:: Sokiran, E V
Tematy:: Early-Middle Frasnian
Frasnian
cyrtospiriferid brachiopod
brachiopod
East European Platform
paleontology
Russia
Brachiopoda
Cyrtospiriferidae; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Paleobiologii PAN
Powiązania:: https://bibliotekanauki.pl/articles/21097.pdf Link otwiera się w nowym oknie
Opis:: The cyrtospiriferids are among the most important fossils in the Frasnian strata of the East European Platform (EEP). During the Early Frasnian (Palmatolepis falsiovalis Zone) the numerous and morphologically distinct Uchtospiriferinae, accompanied by very scarce Cyrtospiriferinae, are known from South Timan. The mass appearance of cyrtospiriferins on the platform at the beginning of the Middle Frasnian is linked with significant sea−level rise of Devonian Transgression−Regression (T−R) cycle IIc. At that interval these brachiopods attain their highest diversity of the entire Frasnian. The Early Frasnian type species of the genus Uchtospirifer is here revised, and subfamily Uchtospiriferinae re−established. Cyrtospirifer schelonicus, C. rudkinensis, C. mylaensis sp. nov., and C. tenticulum are described from the Middle Frasnian of NW and central regions of EEP and Middle Timan.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: Benthic ostracods from the Early-Middle Frasnian transition in the north-western East European Platform, Russia
Autorzy:: Evdokimova, I O
Tematy:: benthic ostracod
ostracod
Early-Middle Frasnian
Frasnian
paleontology
East European Platform
Russia
Ostracoda
Main Devonian Field; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Paleobiologii PAN
Powiązania:: https://bibliotekanauki.pl/articles/21796.pdf Link otwiera się w nowym oknie
Opis:: Pronounced changes in benthic ostracod associations in the north−west part of the East European Platform, across the Early–Middle Frasnian (Devonian) transition, track a marine transgression event. More than 80 ostracod species belonging to the Eifelian Mega−Assemblage were recorded. Cavellinidae and Acratiidae generally dominate the Early Frasnian Sargaevo Horizon. Middle Frasnian ostracod associations of the Semiluki Horizon are more diverse and are characterised by different dominant both geographically and stratigraphically, resulting from significant palaeo−basin bottom relief and benthic biotope differentiation. The ostracod associations are indicative of very shallow, well oxygenated semi−restricted epeiric environment, with occasional marine influence, alternating with short periods of open shelf conditions. The relative abundance of ostracod species in the different associations, and faunal diversity indices, show considerable variations throughout the Early–Middle Frasnian, and suggest a less restricted position within an intra−platform setting in the Middle Frasnian, relative to a more restricted ostracod habitat in the Early Frasnian. The succession of Early–Middle Frasnian micro−benthic associations within the Main Devonian Field seems to be of a regional scale, and resulted from a marine regression−transgression couplet, corresponding to eustatic cycles IIb–IIc. This was paired with synsedimentary tectonic subsidence in adjacent areas of the north−east East European Platform, progressively improving marine water circulation in the extremely shallow−water shelf seas.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: Growth in early species of the conodont Ancyrodella and implications for correlation of the Middle-Upper Devonian boundary
Autorzy:: Miller, C.G.
Tematy:: conodonts
Devonian
Givetian
Frasnian
Ancyrodella
ontogeny; Pokaż więcej
Wydawca:: Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Powiązania:: https://bibliotekanauki.pl/articles/2059511.pdf Link otwiera się w nowym oknie
Opis:: The first occurrence of the conodont Ancyrodella rotundiloba has been used extensively for correlating the Middle-Up per Devonian (Givetian-Frasnian) boundary in sections worldwide despite many arguments as to its precise taxonomic definition. These arguments are summarised herein and three ontogenetic series illustrated from three samples across the Givetian-Frasnian boundary within the Vorota Formation of the Kozhym River section, Sub-Polar Urals, Russia. General trends within the three ontogenetic series suggest that the ratio of basal pit width to platform width in Ancyrodella pristina, and Ancyrodella recta in creases through ontogeny but the morphology of lateral secondary keel extensions to the basal pit remains constant and is a useful taxonomic feature. Folds and collars on the basal surface occur only in the later stages of development. The out line of the platform within species is variable and controlled by the formation of incipient nodes in juveniles; gerontic specimens can also have very variable platform out lines. Measure ments of platform width to basal pit width ratios and platform shape out lines may not therefore be a good way to compare between species. The three ontogenetic series provide typical late Givetian and early Frasnian examples and increase the potential for correlation of the Middle-Upper Devonian boundary particularly using juvenile Ancyrodella specimens.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: Revision of latest Givetian-Frasnian Atrypida [Brachiopoda] from central North America
Autorzy:: Day, J
Copper, P
Tematy:: Late Frasnian
fauna
brachiopod fauna
Frasnian
Late Devonian
Devonian
Atrypida
taxonomy
North America
Givetian
Brachiopoda
paleontology; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Paleobiologii PAN
Powiązania:: https://bibliotekanauki.pl/articles/20627.pdf Link otwiera się w nowym oknie
Opis:: The brachiopod fauna of the Middle-Late Devonian cratonic carbonate platform deposits of the Iowa Basin, central North America, contains twenty species of the order Atrypida, some of which are types for widespread genera common in Middle and Late Devonian faunas. The latest Givetian-early Frasnian deposits yield a diverse fauna consisting of ten species (two new) included in Desquamatia (Independatrypa), D. (Seratrypa), Pseudoatrypa, Radiatrypa, Spinatrypa (Spinatrypa) and Spinatrypina (Exatrypa). Many of these forms occur in, or are closely similar to species known from, coeval faunas of central and western Canada. Middle Frasnian deposits of northern Iowa contain two species included in Spinatrypa (S.) and Pseudoatrypa, both of which are new. Late Frasnian strata of the Iowa Basin yield eight species included in Costatrypa, Iowatrypa, Pseudoatrypa, and Spinatrypa (Spinatrypa), some of which are widespread in other subtropical and tropical faunas of the western US and western Canada. The taxa Pseudoatrypa witzkei sp. n., Spinatrypa (S.) bunkeri sp. n., Spinatrypa (S.) thompsoni sp. n., and Spinatrypina (Exatrypa) johnsoni sp. n. are proposed. Pseudoatrypa? sp. from the very late Frasnian of southern New Mexico is also illustrated.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:: Early Frasnian acanthodians from Central Iran
Autorzy:: Hairapetian, V.
Valiukevicius, J.
Burrow, C.J.
Tematy:: Acanthodii
Central Iran
Climatiidae
dental element
Diplacanthidae
Early Frasnian
Frasnian
Iran
Ischnacanthiformes
acanthodian
paleontology
histology
Devonian
systematics; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Paleobiologii PAN
Powiązania:: https://bibliotekanauki.pl/articles/20209.pdf Link otwiera się w nowym oknie
Opis:: Two vertebrate−bearing horizons in the basal Frasnian carbonate of the Chahriseh section, northeast of Esfahan, yielded microremains of thelodonts, placoderms, acanthodians, actinopterygians, chondrichthyans, and sarcopterygians, considerably expanding the vertebrate faunal list for the strata. Acanthodians comprise a diverse association of climatiids, diplacanthids, and ischnacanthiforms, including the previously recorded climatiid Nostolepis sp. cf. N. gaujensis, as well as one new climatiid genus and several taxa left in open nomenclature. Climatiid Iranolepis ginteri gen. et sp. nov. is diagnosed by having scales with a highly raised medial crown area separated by steep slopes from lateral crown areas; an odontocytic mesodentine of maximum extent in the crown, distinguished by extensive network of fine canaliculi with abundant tiny osteocytes; and a poorly developed stranggewebe system. Other scales with fan−like symmetrically grooved crowns conform to the Diplacanthus−type histologically, and have many characters in common with Milesacanthus antarctica from the Aztec Siltstone of Antarctica. Osseous gnathal elements include mesodentinous tooth whorls from an ischnacanthiform or climatiid, and ischnacanthiform jaw bones with large chambers for vascular canals, distinctly separated cylindrical tooth cusps along the lingual ridge, and wide−based, triangular, weakly striated cusps on the main lateral ridge. The acanthodian association, accompanied by the Frasnian conodonts of the middle Mesotaxis falsiovalis to Palmatolepis hassi zones and zonal thelodonts Turinia hutkensis and Australolepis seddoni, is proving useful for biostratigraphy, showing similarities with assemblages from both Gondwana and the Old Red Sandstone Continent.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 9.

Tytuł:: Faunal and facies changes at the Early-Middle Frasnian boundary in the north-western East European platform
Autorzy:: Zhuravlev, A V
Sokiran, E.V.
Evdokimova, I.O.
Dorofeeva, L.A.
Rusetskaya, G.A.
Malkowski, K.
Tematy:: fauna change
Early-Middle Frasnian
East European Platform
Conodonta
Brachiopoda
Ostracoda
correlation
carbon isotope
Frasnian
Main Devonian Field; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Paleobiologii PAN
Powiązania:: https://bibliotekanauki.pl/articles/20261.pdf Link otwiera się w nowym oknie
Opis:: Multidisciplinary study of the Early–Middle Frasnian boundary in the north−western East European Platform (Main Devonian Field) allows evaluation of changes in facies, brachiopod, ostracod, and conodont associations, as well as carbon isotope composition. Brachiopod and ostracod faunas, characterized by predominance of rhynchonellids, spiriferids, podocopids, and platycopids in the Early Frasnian, and by predominance of spiriferids, palaeocopids, and kloedenellocopids in the Middle Frasinan, demonstrate significant changes in dominance and diversity likely caused by regressiontransgression couplets in the extremely shallow−water environment. Changes in diversity of the conodont associations, represented mainly by shallow−water polygnathids and spathognathids, are controlled by sea−level fluctuations as well; however significant evolutionary turnover is absent. Deepening pulses lead to an increasing in diversity of both the benthic and nectic groups, whilst regressions cause diversity fall due to progressive habitat reduction. Most prominent decreasing in the fauna diversity is observed in the late Early Frasnian (Dubnik time) coinciding with the regressive phase of the Late Givetian to Early Frasnian eustatic cycle. Positive−negative δ¹³C excursion, detected in brachiopod calcite from the early interval of the Middle Frasnian, can be correlated with global isotopic perturbations near the Frasnian substage boundary: the positive 2.6‰ δ¹³C excursion is probably linked with enhanced primary production in high−nutrient regimes in the epeiric sea.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 10.

Tytuł:: Stratigraphy and geological events at the Frasnian-Famennian boundary in the Southern Urals
Autorzy:: Veimarn, A. B.
Puchkov, V. N.
Abramova, A. N.
Artyushkova, O. V.
Baryshev, V. N.
Degtyaryov, K. E.
Kononova, L. I.
Maslov, V. A
Mosejchuk, V. M.
Pazukhin, V. N.
Pravikova, N. V.
Tevelev, A. V.
Yarkova, A. V.
Tematy:: Frasnian-Famennian boundary
Southern Urals
conodonts
superplume; Pokaż więcej
Wydawca:: Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Powiązania:: https://bibliotekanauki.pl/articles/2058843.pdf Link otwiera się w nowym oknie
Opis:: Detailed biostratigraphic correlation of late Frasnian and Famennian sections in the Southern Urals shows that the key global scale events near the boundary of Frasnian and Famennian are clearly expressed in combination with important regional scale tectonic events. The maximum regression occured during triangularis zones time, being recorded as common hiatuses. The beginning of specific ultra- potassic mantle volcanism took place during the linguiformis Zone. Processes of olistostrome deposition, uplift of the Uraltau zone, the start of flysch deposition, and exhumation of the high pressure-low temperature Maksiutovo metamorphic complex also took place very close to the Frasnian-Famennian boundary, as the general regression coincided with active local tectonic movements as the Magnitogorsk island arc collised with the East European continent. The global scale events at the F-F boundary are connected with activity of the Late Devonian superplume, which encompassed a vast area of the Kazakhstanian, East European, Siberian, Gondwana and South Chinese plates.
Dostawca treści:: Biblioteka Nauki

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