Wyniki wyszukiwania - BazTech

1

Aptychi from the Berriasian/Valanginian (France and Spain) : new stratigraphical and morphological details

Vašíček Z., Janssen N. M .M., Klein J.

Annales Societatis Geologorum Poloniae

|

2016

|

Vol. 86, No. 3

265--272

EN

Late Berriasian–earliest Valanginian lamellaptychi (Cephalopoda) are described in detail for the first time. With one exception, all species belong to early representatives of Mortilletilamellaptychus. The majority of the well dated aptychi come from the cephalopod-rich sediments of the Vocontian Basin in south-eastern France; others are from south-eastern Spain. Thorolamellaptychus anglesensis sp. nov. is introduced.

2

Towards a standard Tithonian to Valanginian calpionellid zonation of the Tethyan Realm

Lakova I., Petrova S.

Acta Geologica Polonica

|

2013

|

Vol. 63, no. 2

201--221

EN

A calpionellid zonal scheme is proposed for the Tithonian through Valanginian pelagic carbonates of the Western Balkan Unit, based on the vertical ranges of 57 chitinoidellid and calpionellid species recognized. This zonal scheme consists of calpionellid zones that are widely accepted in the Mediterranean Realm, such as the zones of Chitinoidella, Praetintinnopsella, Crassicollaria, Calpionella, Calpionellopsis, Calpionellites and Tintinnopsella. Subzonal divisions are comparable to those in the Carpathians. Direct correlations between ammonite and calpionellid ranges suggest that the base of the Upper Tithonian corresponds to the FO of Chitinoidella boneti; that of the Upper Berriasian to the FO of the genus Calpionellopsis; and the base and top of the Lower Valanginian to the FO and LO of the genus Calpionellites respectively. Correlations of the calpionellid zonation in the study area with zonations in other areas are discussed.

3

Chronostratigraphic significance of an early Valanginian (Cretaceous) calpionellid association (Hochkogel section, Upper Austria, Northern Calcareous Alps)

Lukeneder A., Reháková D.

Geological Quarterly

|

2007

|

Vol. 51, No 1

27-38

EN

Early Cretaceous calpionellid samples were collected at the ammonoid-bearing Hochkogellocality in the southern most part of the Reichraming Nappe (Ebenforst Syncline, Northern Calcareous Alps). The microfossil fauna sampled from limestone parts of the Rossfeld Formation indicates an early Valanginian age. The standard Calpionellites Zone (with darderi and major subzones) coincides with the early Valanginian ammonoid zones of Busnardoites campylotoxus and Tirnovella pertransiens. The deposition of the limestones in this area occurred in an unstable environment disturbed by gravitational transport which accounts for the different sedimen tary components and accompanying fossils in the accumulated layers, transported from a source area situated to the south.

4

Biostratigraphy and palaeoenvironmental development of the Callovian-Valanginian carbonate platform from the Lyubash unit (SW Bulgaria)

Ivanova D., Koleva-Rekalova El, Kołodziej B., Metodiev L., Roniewicz E.

Volumina Jurassica

|

2006

|

Vol. 4, no. 1

174-175

EN

This study deals with the successions located in the Lyubash unit (SW Bulgaria), which represents a part of the Moesian Carbonate Platform in Middle Jurassic – Early Cretaceous time interval. According to the recent tectonic scheme of Bulgaria (Dabovski et al. 2002) the Lyubash unit belongs to Srednogorie tectonic zone of the Balkan orogenic system. Three sections have been sampled and studied – Rebro, Lyalintsi and Velinovo, which are built up by thick-bedded to massive light grey to whitish organogenic and micritic limestones of the Javorets, Gintsi and Slivnitsa formations. Detailed studies on foraminifera and calcareous dinocyst, provided new biostratigraphic data, and confirmed the Middle Callovian-Valanginian age of the examined sediments as assumed previously by Sapunov et al. (1985). Foraminifera are particularly abundant in the lagoon facies, and represented by genera: Globuligerina, Ophthalmidium, Cornuspira, Ammobaculites, Mesoendothyra, Labyrinthina, Kurnubia, Pseudocyclammina, Dobrogelina, Rumanoloculina, Hechtina, Meandrospira, Valvulina, Trocholina, and Neotrocholina. The sedimentological analysis allowed recognizing microfacies groups assigned to three facies zones: platform slope facies, reef and peri-reef facies and lagoon-tidal flat facies. The development of the platform is characterized by complex vertical and lateral alternation of the studied microfacies. Platform slope facies are prevalent at the section Rebro; the Lyalintsi section is dominated by reef and peri-reef facies, and the section Velinovo is mainly dominated by lagoon facies. Sea-level fluctuations are observed, however generally, a shallowing-upward trend in the platform evolution is observed in all three sections. Coral-microbial reefs are developed as biostromes, and contain numerous and highly differentiated scleractinian corals: 70 species (6 new) from 50 genera (4 new). Among them following corals are the most common: phacelloid Latomeandra, Stylosmilia, Thecosmilia, Cladophyllia, ramose Solenocoenia, Meandrophyllia, lameller Synastraea and Microsolena. Reef development has been disturbed by sea level rise, evidenced by limestones with Saccocoma, intercalated with coral biostromes.

5

First nearly complete skeleton of the Cretaceous duvaliid belemnite Conobelus

Lukeneder A.

Acta Geologica Polonica

|

2005

|

Vol. 55, no. 2

147-162

EN

The first Cretaceous belemnite preserved with the rostrum, slightly compressed phragmocone and part of the proostracum is described from the Early Cretaceous (Late Valanginian) Rossfeld Formation (Eibeck, Reichraming Nappe of the Northern Calcareous Alps). The rostrum has dorsal groove (alveolar furrow) typical of duvaliids, and its conical shape (round in transverse section outline), and the rounded apex allow its attribution to Conobelus Stolley, 1919. The new species C. pseudoheres sp. nov. is proposed based on the unique features of the specimen, i.e. persistently parallel lateral sides throughout the rostrum and the conical, blunt outline at the apex. The ration between rostrum and phragmocone is 0.78; the distances between the calcitic septa of the anterior end of the phragmocone range from 3 to 5 mm. The proostracum is 0.02 mm thick. The apical angle is 32° and the alveolar angle (posterior end of the phragmocone) is 24°.The alveolus is 40 mm long, yielding a ratio between rostrum and alveolus of 1.86. The depositional history with its fast sedimentation along with absent/limited post-mortem transportation led to extraordinarily good preservation of the examined specimen.