Guadalupian (Middle Permian) Conodonts of Sponge-Bearing Limestones from the Margins of the Delaware Basin, West Texas

The Guadalupian Series (with Roadian, Wordian and Capitanian stages in ascending order) is very suitable for world-wide application as the Middle Permian standard. The conodont faunas of the Delaware Basin and its slope are dominated by pelagic forms represented by ribbed Mesogondolella restricted to the Middle Permian of intraplatform basins and to near-shore slopes of tropical open seas. The first appearance of the serrated Mesogondolella nankingensis (CHING) is important for the definition of the base of the Middle Permian (base of the Guadalupian Series = base of the Roadian Stage). Mesogondolella nankingensis evolved in a phylomorphogenetic cline from the unserrated M. idahoensis (YOUNGQUIST, HAWLEY & MILLER) through transition forms closely related to M. phosphoriensis (YOUNGQUIST, HAWLEY & MILLER). The appearance of serrated Mesogondolella is a very characteristic event in Permian conodont evolution, which can be traced in southwestern and western North America, Arctic Canada and in China. This event is very suitable for the world-wide correlation of the base of the Middle Permian Guadalupian Series. At the upper boundary of the Guadalupian, the serrated Mesogondolella shannoni WARDLAW changed in a phylomorphogenetic cline into the smooth Clarkina altudaensis KOZUR. This cline was also found in intraplatform basins of the eastern Tethys (China). For this reason, the top of the Guadalupian can be well correlated with the Tethyan scale, in which the Late Permian Lopingian Series is defined. The first appearance of Clarkina crofti KOZUR & LUCAS in the uppermost Lamar Limestone and in the uppermost Altuda Formation is very important as it is penecontemporaneously with the first appearance of C. altudaensis. This species is restricted to greater water depths. Two new conodont species, Hindeodus gulloides n. sp., and H. altudaensis n.sp. are described. Additionally, Clarkina crofti KOZUR & LUCAS n.sp. is described to avoid the use of nomina nuda, because the paper of KOZUR & LUCAS (in press) has not yet been printed

The Germanic Triassic: correlations with the international chronostratigraphic scale, numerical ages and Milankovitch cyclicity

Die biostratigraphische Gliederung der marinen Tethys wird ausführlich diskutiert. Ihre Korrelation mit der Germanischen Trias ist nur zum Teil gut belegt, zum Teil biostratigraphisch gar nicht möglich. Marine Abschnitte des Oberen Buntsandsteins und der Untere Muschelkalk enthalten nicht endemische Faunen von Conodonten, Ammonoideen und Echinodermaten und können dem internationalen Standard gut zugeordnet werden. Im Oberen Muschelkalk ist die Conodonten- und Ammoniten- reiche Fauna dagegen weitgehend endemisch und deshalb nur schwer korrelierbar. In kontinentalen Ablagerungen ermöglichen Conchostraken und Sporomorphen eine gute Korrelation. Diese Formen fehlen jedoch in roten hypersalinaren Ablagerungen, wie z. B. der Weser-Formation. Die Magnetostratigraphie kann in der Zukunft ein hohes Korrelationspotential haben, aber nur, wenn dabei bio- und chronostratigraphische Methoden berücksichtigt werden. Gut realisiert ist dies bisher an der Perm-Trias-Grenze in Deutschland und im Mittleren Nor bis Rhät von England. δ13Corg- and δ13Ccarb-Isotopen sowie Mikrokügelchen (microsphaerules) kosmischer, vulkanischer und organischer Entstehung sind wichtige Korrelationsmethodenan der Perm-Trias-Grenze. δ13Ccarb gibt gute Resultate bis ins tiefere Smithium. Die wichtigsten Ergebnisse der Arbeit sind: (1) eine revidierte Conchostraken-Gliederung des Buntsandsteins und deren Korrelation mit den kurzen Exzentrizitätszyklen des Unteren Buntsandsteins; (2) eine detaillierte Korrelation des tieferen Olenekiums mit Hilfe von Conchostraken und einer revidierten Magnetostratigraphie; (3) die Zuordnung der Stammen-Schichten und des zeitgleichen Thüringer Chirotheriensandsteins (obere Solling-Formation) zum Anis (Aegeum); (4) die Korrelation der Untergrenze Ladin (Basis E. curionii-Zone) mit einem Intervall über der Cycloidesbank γ (Oberer Muschelkalk); (5) die Zuordnung der obersten Löwenstein-Formation (4. Stubensandstein), der zeitgleichen obersten Arnstadt-Formation sowie der Unteren und Mittleren Postera-Schichten zum Rhät. Die meisten der deutlich entwickelten Sedimentationszyklen in der Germanischen Trias werden als Milankovitch-Zyklen von ~20 kyrs, ~100 kyrs and ~400 kyrs interpretiert, wobei diekurzen Exzentrizitätszyklen von ~100 kyrs anscheinend am besten ausgeprägt sind. Im Unteren Buntsandstein gibt es 22 kurze Exzentrizitätszyklen, in der Volpriehausen-Formation zwischen 9 und 14, in der Detfurth-Formation mindestens 3 und in der Solling-Formation wahrscheinlich 4. Gut ausgebildete kurze Exzentrizitätszyklen treten im Oberen Buntsandstein auf (9), im Unteren Muschelkalk (20 Zyklen und der untere Teil eines 21.) und im Mittleren Muschelkalk (9). Die unfähr 40 Zyklen im Oberen Muschelkalk sind wahrscheinlich ebenfalls kurze Exzentrizitätszyklen. Gut ausgebildete kurze Exzentrizitätszyklen gibt es auch in der Erfurt-Formation (8) undder Grabfeld-Formation unterhalb der Estherienschichten (9). Mehrere Schichtlücken treten in der Unteren und Mittleren Trias auf. In der Germanischen Obertrias sind die Milankovitch-Zyklen schwerer zu bestimmen, vor allem wegen großen Schichtlücken, verringerten Sedimentationsraten und Kondensation durch Bodenbildung. In der Arnstadt-Formation sind offenbar die ~400 kyrs-Zyklen am Besten entwickelt, wie es auch in der Obertrias des Newark-Beckens der Fall ist.The biostratigraphy of the Tethyan marine scale is discussed in some detail. Its correlation with the Germanic Triassic is partly rather well established, in part biostratigraphically impossible. Those marine deposits that do not contain an endemic fauna can be well assigned to the international scale, mainly with conodonts, ammonoids and echinoderms (Upper Buntsandstein, Lower Muschelkalk). The marine ammonoid- and conodont-rich Upper Muschelkalk faunas are endemic and very difficult to correlate with the Tethyan scale. Conchostracans and sporomorphs allow a good correlation of continental beds, but red hypersaline beds have neither sporomorphs nor conchostracans (e. g. Weser Formation). An important future correlation potential can be magnetostratigraphy, if bio- and chronostratigraphy are integrated in both the Germanic Basin and the Tethys. So far, it is particularly well established around the Permian-Triassic Boundary in Germany and in the middle Norian to Rhaetian of England. δ13Corg and δ13Ccarb isotopes and microsphaerules of cosmic, volcanic and biotic origin are significant correlation tools around the Permian-Triassic boundary, δ13Ccarb yields also good results for correlation up to the the lower Smithian. Most important results are: (1) a revised conchostracan zonation of the Buntsandstein and its correlation with the short eccentricity cycles of the entire Lower Buntsandstein; (2) a detailed correlation of the Olenekian base by conchostracans and by a revised magnetostratigraphy; (3) the assignment of the Stammen Beds (and the time-equivalent Thüringer Chirotheriensandstein) of the upper Solling Formation to the Anisian (Aegean); (4) the correlation of the Ladinian base (at the base of the E. curionii Zone) with a level above the Cycloidesbank γ of the Upper Muschelkalk; and (5) the assignment of the uppermost Löwenstein Formation (4th Stubensandstein), the timeequivalent uppermost Arnstadt Formation as well as the lower and middle Postera Beds to the Rhaetian. The pronounced cyclicity of the Germanic Triassic is interpreted in terms of Milankovitch cycles of ~0.02 myrs, ~0.1 myrs and ~0.4 myrs, whereby the short eccentricity cycles of ~0.1 myrs seem to be best developed. There are 22 short eccentricity cycles in the Lower Buntsandstein. Regarding the Middle Buntsandstein, there seems to be between 9 and 14 short eccentricity cycles in the Volpriehausen Formation, at least 3 in the Detfurth Formation and probably 4 in the SollingFormation. Well developed short eccentricity cycles are known from the Upper Buntsandstein Röt Formation (9) as well as from the Lower Muschelkalk (20, and the lower part of a 21th cycle) and Middle Muschelkalk (9). The approximately 40 cycles of the Upper Muschelkalk are most likely short eccentricity cycles. Well developed short eccentricity cycles are present in the Erfurt Formation (8), and in the Ladinian part of the Grabfeld Formation (9). Several shorter or longer well-known gaps have to be considered in the Lower and Middle Triassic. In the Germanic Upper Triassic the Milankovitch cycles are more difficult to establish, especially due to several long gaps, reduced sedimentation rates and condensation associated with pedogenic processes. It seems that in the Arnstadt Formation the ~0.4 myrs cycles are best developed as is the case in the Upper Triassic of the Newark Basin

New Stratigraphic and Palaeogeographic Results from the Palaeozoic and Early Mesozoic of the Middle Pontides (Northern Turkey) in the Azdavay, Devrekani, Küre and Inebolu Areas: Implications for the Carboniferous-Early Cretaceous Geodynamic Evolution and Some Related Remarks to the Karakaya Oceanic Rift Basin

The Küre Complex of the Middle Pontides, northern Turkey, is not a remnant of the Palaeotethys but consists of three different units with differing geological history, the Küre Ridge Unit, the Küre Ocean Unit and the Çalça Unit. The Küre Ridge Unit consists of the Serveçay Group, a pre-Permian, low-grade metamorphic Variscan oceanic sequence, and the Sirçalik Group, a Lower and Middle Triassic shallow-water sequence of North Alpine facies and event succession which disconformably overlies the Serveçay Group. Following a hiatus, the Sirçalik Group is overlain by marginal parts of the Akgöl Group with olistoliths of local origin which were derived mainly from the Sirçalik Group. The Küre Ocean Unit consists mostly of the Akgöl Group (siliciclastic turbidites and olistostromes of the Karadagtepe Formation, which is a middle Carnian to Middle Jurassic accretionary complex from the southern, active margin of the Küre Ocean, and mainly Middle Jurassic molasse type shallow-water sandstones, siltstones and shales of an unnamed formation) and of thick oceanic basalts (Ipsinler Basalt). Tectonic slices of Middle Triassic to lower Carnian ophiolites and basalts are also present. The Karadagtepe Formation contains numerous Middle Triassic exotic olistoliths and blocks of shallow-water and predominantly slope and basinal limestones, ocean-floor deep-sea sediments (shales and radiolarites), basalts and small clasts of ophiolites or ophiolitic detritus. The Çalça Unit consists of deposits from the northern, passive margin of the Küre ocean with many Pelsonian to upper Norian Hallstatt Limestones and Rhaetian-Lower Jurassic (?Middle Jurassic) deep-water shales and marls. All three units are overlain following a period of non deposition by the Upper Jurassic Bürnük Formation (red conglomerate, sandstone) and Inalti Formation (shallow-water platform carbonates). The Küre Ridge Unit was split away from the Variscan Sakarya Continent by the opening of the Karakaya oceanic rift basin during latest Permian (Dorashamian) and became a continental splinter between the Karakaya oceanic rift basin and the Küre Ocean (opened during the late Scythian). Southward subduction began in the Küre Ocean during the middle Carnian (beginning of the Karadagtepe siliciclastic turbidites), whereas at the northern passive margin the deposition of Hallstatt Limestones continued until the latest Norian. The deposition of siliciclastic turbidites and olistostromes (Diskaya Unit) began in the entire Karakaya oceanic rift basin during the middle Carnian, and ocean basin deposits (radiolarites, pelagic limestones) and slope deposits form the passive margin (e.g., Hallstatt Limestones) are no more present in the Karakaya oceanic rift basin indicating that this basin was very narrow (only a few hundreds of kilometres). During the late Norian, the Karakaya oceanic rift basin closed, whereas subduction at the southern (active margin) of the Küre ocean continued. At the northern margin of the (Upper Triassic?) Jurassic-Lower Cretaceous Beykoz-Çaglayan turbidite basin (north of the Küre Complex) the accretionary complex of an older ocean, the Late Palaeozoic Paphlagonian Ocean, was exposed that yielded clasts in the Beykoz-Çaglayan turbidite basin. Among these clasts Carboniferous to Middle Permian (Capitanian) pelagic rocks (pelagic limestones, radiolarites) could be dated. A Middle to Late Permian southward-directed subduction is assumed for the Paphlagonian Ocean. Its closure occurred either at the end of the Permian or during the Scythian

Carbon isotope signatures of latest Permian marine successions of the Southern Alps suggest a continental runoff pulse enriched in land plant material

The latest Permian mass extinction, the most severe Phanerozoic biotic crisis, is marked by dramatic changes in palaeoenvironments. These changes significantly disrupted the global carbon cycle, reflected by a prominent and well known negative carbon isotope excursion recorded in marine and continental sediments. Carbon isotope trends of bulk carbonate and bulk organic matter in marine deposits of the European Southern Alps near the low-latitude marine event horizon deviate from each other. A positive excursion of several permil in &delta;¹³C_org starts earlier and is much more pronounced than the short-term positive ¹³C_carb excursion; both excursions interrupt the general negative trend. Throughout the entire period investigated, ¹³C_org values become lighter with increasing distance from the palaeocoastline. Changing ¹³C_org values may be due to the influx of comparatively isotopically heavy land plant material. The stronger influence of land plant material on the ¹³C_org during the positive isotope excursion indicates a temporarily enhanced continental runoff that may either reflect increased precipitation, possibly triggered by aerosols originating from Siberian Trap volcanism, or indicate higher erosion rate in the face of reduced land vegetation cover. <br><br> doi:<a href="http://dx.doi.org/10.1002/mmng.201300004" target="_blank">10.1002/mmng.201300004</a

İzmir‐Ankara suture as a Triassic to Cretaceous plate boundary – data from central Anatolia

The İzmir‐Ankara suture represents part of the boundary between Laurasia and Gondwana along which a wide Tethyan ocean was subducted. In northwest Turkey, it is associated with distinct oceanic subduction‐accretion complexes of Late Triassic, Jurassic and Late Cretaceous ages. The Late Triassic and Jurassic accretion complexes consist predominantly of basalt with lesser amounts of shale, limestone, chert, Permian (274 Ma zircon U‐Pb age) metagabbro and serpentinite, which have undergone greenschist facies metamorphism. Ar‐Ar muscovite ages from the phyllites range from 210 Ma down to 145 Ma with a broad southward younging. The Late Cretaceous subduction‐accretion complex, the ophiolitic mélange, consists of basalt, radiolarian chert, shale and minor amounts of recrystallized limestone, serpentinite and greywacke, showing various degrees of blueschist facies metamorphism and penetrative deformation. Ar‐Ar phengite ages from two blueschist metabasites are ca. 80 Ma (Campanian). The ophiolitic mélange includes large Jurassic peridotite‐gabbro bodies with plagiogranites with ca. 180 Ma U‐Pb zircon ages. Geochronological and geological data show that Permian to Cretaceous oceanic lithosphere was subducted north under the Pontides from the Late Triassic to the Late Cretaceous. This period was characterized generally by subduction‐accretion, except in the Early Cretaceous, when subduction‐erosion took place. In the Sakarya segment all the subduction accretion complexes, as well as the adjacent continental sequences, are unconformably overlain by Lower Eocene red beds. This, along with the stratigraphy of the Sakarya Zone indicate that the hard collision between the Sakarya Zone and the Anatolide‐Tauride Block took place in Paleocene

Hydrothermal dolomitization of basinal deposits controlled by a synsedimentary fault system in Triassic extensional setting, Hungary

Dolomitization of relatively thick carbonate successions occurs via an effective fluid circulation mechanism, since the replacement process requires a large amount of Mg-rich fluid interacting with the CaCO3 precursor. In the western end of the Neotethys, fault-controlled extensional basins developed during the Late Triassic spreading stage. In the Buda Hills and Danube-East blocks, distinct parts of silica and organic matter-rich slope and basinal deposits are dolomitized. Petrographic, geochemical, and fluid inclusion data distinguished two dolomite types: (1) finely to medium crystalline and (2) medium to coarsely crystalline. They commonly co-occur and show a gradual transition. Both exhibit breccia fabric under microscope. Dolomite texture reveals that the breccia fabric is not inherited from the precursor carbonates but was formed during the dolomitization process and under the influence of repeated seismic shocks. Dolomitization within the slope and basinal succession as well as within the breccia zones of the underlying basement block is interpreted as being related to fluid originated from the detachment zone and channelled along synsedimentary normal faults. The proposed conceptual model of dolomitization suggests that pervasive dolomitization occurred not only within and near the fault zones. Permeable beds have channelled the fluid towards the basin centre where the fluid was capable of partial dolomitization. The fluid inclusion data, compared with vitrinite reflectance and maturation data of organic matter, suggest that the ascending fluid was likely hydrothermal which cooled down via mixing with marine-derived pore fluid. Thermal gradient is considered as a potential driving force for fluid flow

A new bivalve fauna from the Permian-Triassic boundary section of southwestern China

A new marine bivalve fauna from the continuous Upper Permian Longtan Formation to Lower Triassic Yelang Formation of the Zhongzai section in southwestern China is documented. Four bivalve assemblages spanning the Permian&ndash;Triassic boundary are recognized and regionally correlated in South China. The bivalve assemblages changed from elements dominated by Palaeozoic types to those dominated by Mesozoic types. Three new species, Claraia zhongzaiensis sp. nov., Claraia sp. nov. 1 and Claraia sp. nov. 2, are described

First record of Rhabdoceras suessi (Ammonoidea, Late Triassic) from the Transylvanian Triassic Series of the Eastern Carpathians (Romania) and a review of its biochronology, paleobiogeography and paleoecology

Abstract The occurrence of the heteromorphic ammonoid Rhabdoceras suessi Hauer, 1860, is recorded for the first time in the Upper Triassic limestone of the Timon-Ciungi olistolith in the Rarău Syncline, Eastern Carpathians. A single specimen of Rhabdoceras suessi co-occurs with Monotis (Monotis) salinaria that constrains its occurrence here to the Upper Norian (Sevatian 1). It is the only known heteromorphic ammonoid in the Upper Triassic of the Romanian Carpathians. Rhabdoceras suessi is a cosmopolitan species widely recorded in low and mid-paleolatitude faunas. It ranges from the Late Norian to the Rhaetian and is suitable for high-resolution worldwide correlations only when it co-occurs with shorter-ranging choristoceratids, monotid bivalves, or the hydrozoan Heterastridium. Formerly considered as the index fossil for the Upper Norian (Sevatian) Suessi Zone, by the latest 1970s this species lost its key biochronologic status among Late Triassic ammonoids, and it generated a controversy in the 1980s concerning the status of the Rhaetian stage. New stratigraphic data from North America and Europe in the subsequent decades resulted in a revised ammonoid biostratigraphy for the uppermost Triassic, the Rhaetian being reinstalled as the topmost stage in the current standard timescale of the Triassic. The geographic distribution of Rhabdoceras is compiled from published worldwide records, and its paleobiogeography and paleoecology are discussed