The Triassic timescale: an introduction

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 Raràu 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. Central European Geology, Vol. 53/2-3, pp. 261-309 (2010) DOI: 10.1556/CEuGeol.53.2010 First While examining the fossils collected by the senior author in an old quarry in limestone of the Timon-Ciungi olistolith, the junior author, whose aim was to study the nautiloids, identified a fragment of a specimen of Rhabdoceras suessi Hauer, 1860, in the material. Consequently the purpose of the present paper is to describe this specimen, and to discuss the biostratigraphic range, chronostratigraphic relevance, and the paleobiogeographic distribution and paleoecology of this Late Triassic heteromorphic ammonoid. Geologic and stratigraphic settingsThe Timon-Ciungi olistolith, along with many other olistoliths composed of Triassic sedimentary and/or ophiolitic rocks, is embedded in Lower Cretaceous wildflysch that infills the Raràu Syncline of the Bucovinian Nappe in the northern part of the inner Eastern Carpathians (Sàndulescu 1973). The Triassic rocks of the olistoliths and also of several large klippen scattered along the inner zone of the Eastern Carpathians, in the Raràu, Hàghimaş and Perşani Mts, are assigned to several, facially distinctive Transylvanian Triassic Series (Patrulius 1996).The Timon-Ciungi olistolith is located on the left side of the drainage of the Timon Creek, which is a tributary of the Moldova River at the Fundu Moldovei locality (Fig. 1). The olistolith, several tens of meters in length, was largely quarried in the 1960s. The limestone quarry was abandoned for a long time and the area is now entirely reforested, with only few small exposures remaining. The main m...

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“…This is already given, but not explicitly stated, by Krystyn et al (2009), Lucas (2010 and Balini et al (2010).…”

Section: First Record Of Rhabdoceras Suessi (Ammonoidea) From the Tramentioning

confidence: 72%

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

Grădinaru¹,

Sobolev²

2010

Central European Geology

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“…The composition of these Late Triassic assemblages varies, and is often poorly known in part due to a lack of quantitative data. Another complicating factor regarding their evolution includes the fact that the Late Triassic spans ~36 myr (Lucas, 2010;Gradstein et al, 2012, Ogg et al 2016, and the stratigraphical resolution is relatively poor, with a lack of macrofossil data and geochronological dating in many areas. Determining exact stratigraphical occurrences and establishing correlations are therefore difficult, and age assignments of the dinoflagellate cyst records have, as a result, varying levels of uncertainty.…”

Section: Triassic Dinoflagellate Cysts State-of-the-artmentioning

confidence: 99%

“…Knowledge of the composition of the various Late Triassic assemblages varies due to a lack of quantitative data, and is therefore in part poorly known. Another complicating factor regarding their evolution includes the fact that the Late Triassic spans ~36 my (Lucas, 2010;Gradstein et al, 2012, Ogg et al 2016 and the stratigraphical resolution is relatively poor, with a lack of macrofossil data and geochronological dating in most areas. In addition, many relevant publications are relatively old and have applied chrono-and lithostratigraphical nomenclature, which now is outdated, thereby hampering reliable age assignments and correlation.…”

Section: Introductionmentioning

confidence: 99%

The temporal and spatial distribution of Triassic dinoflagellate cysts

Mangerud

Paterson

Riding

2019

Review of Palaeobotany and Palynology

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The records of dinoflagellate cysts from the Late Triassic, the time during which they first appear abundantly in the geological record, are reviewed. Most of the Triassic palynological literature pertains to terrestrial palynomorphs, thus it is challenging to establish a global picture of the temporal and spatial distribution of Late Triassic dinoflagellate cyst around the supercontinent of Pangea. Moreover, data on Late Triassic dinoflagellate cysts are dispersed, and there are currently no records of dinoflagellate cysts from many marine successions. With the exception of an Australian record of the dinoflagellate cyst Sahulidinium ottii from the late Mid Triassic, and a possible early Carnian occurrence of, among others, Rhaetogonyaulax in the Swiss Alps, cyst-forming dinoflagellates first appeared relatively synchronously around Pangea from the late Carnian. There are three to six species of pre-Norian species globally, whereas species richness exceeded 25 by the end of the Norian. During the Rhaetian, marine seaways had gradually opened due to sustained continental breakup, allowing the expansion of dinoflagellates into many European basins. New species are present, some known only from restricted areas, whereas others like Dapcodinium appear to have a global distribution. The majority of Triassic dinoflagellate cyst taxa do not extend into the Jurassic.

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“…= questionable late Anisian, lL‐C = late Ladinian to Carnian, C = Carnian, N = Norian; arrows symbolizing supposed spreading of the Isocrinidae from the far‐eastern part of the Palaeotethys ocean (maybe today’s south‐west China) to various other regions; Anisian palaeogeographical reconstruction modified from Blakey (2010). B, stratigraphical chart with ranges of Isocrinidae in the different regions; reliable ranges in black, stratigraphically questionable occurrences in white to grey; radioisotopic ages after Lucas (2010) and Mundil et al. (2010), supplemented by Subcommission for Stratigraphic Information (2009).…”

Section: Origin and Early Evolution Of The Isocrinidamentioning

confidence: 99%

An early isocrinid sea lily from the middle to late Anisian boundary (Middle Triassic) of south‐west China – evidence for a far‐east Tethyan origin of the family Isocrinidae

Stiller¹

2011

Palaeontology

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The isocrinid sea lily Tyrolecrinus wugangi sp. nov. from uppermost middle to lowermost upper Anisian (lower Middle Triassic) strata of Leidapo near Qingyan, Guizhou Province, south-west China, provides new data on the early phylogeny of the order Isocrinida. The new species is the earliest unequivocal representative of the family Isocrinidae. It predates all other known species of the genus Tyrolecrinus that come from upper Ladinian to Rhaetian strata and also all other known taxa of the Isocrinidae. Nevertheless, its stem is of fully developed isocrinid type and is characteristic of the genus, with consistently synostosial, rarely cryptosymplectial, distal nodal articular facets. These findings indicate that the Isocrinidae evolved prior to the late middle Anisian in the far-eastern part of the Palaeotethys ocean, perhaps in the region forming today's south-west China, and spread to various other regions later in the Middle and Late Triassic. The genus Tyrolecrinus is revised and the new genus Bakonycrinus gen. nov. is erected.

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The Triassic timescale: an introduction

Abstract: German geologists began

Cited by 23 publications

References 37 publications

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

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

The temporal and spatial distribution of Triassic dinoflagellate cysts

An early isocrinid sea lily from the middle to late Anisian boundary (Middle Triassic) of south‐west China – evidence for a far‐east Tethyan origin of the family Isocrinidae

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