Daniel Vachard

New algae and problematica of algal affinity from the permian of the Aseelah Unit of the batain plain (East Oman)

Permian microfloras occur in limestone boulders of the Aseelah Unit at the lower part of the Batain Group (NE Oman). The boulders are composed of bioclastic limestones deposited during the Permian on a shallow marine warm shelf environment. They yield several rich associations of Dasycladales, tubiphytids and Archaeolithophyllaceae indicating a Yakhtashian to Dzhulfian age (dated by fusulinids). The algal-bearing Aseelah Unit overlies conformably the Permian Qarari Unit deposited on the distal slope of the Arabian carbonate platform. The conglomerate and sandstone sheddings of the Aseelah Unit indicate the end of a major transgressive-regressive cycle at the Permian/Triassic boundary. The oldest age of the depositional event is given by the Dzhulfian age of the youngest reworked boulders. The age of the sandstones and sandy matrix is not well established; it is post-Dzhulfian, probably Triassic on the basis of some palynological indications. Several new taxa are described: Aphralysiaceae nov. fam., Sparaphralysia orientalis nov. sp., Mellporellopsis corpulenta nov. gen. nov. sp., Aseelahella granieri nov. gen. nov. sp., Claracrustinae nov. subfam., Claracrusta ungdarelloidea nov. sp. and Sphairionia galinae nov. sp.

Stratigraphy and sequence stratigraphy of the Moscovian in the Donets basin

New results are presented on the stratigraphy based on Fusulinids and Palynomorphs and the sequence stratigraphy of the Moscovian in the Donets basin. They have been developed by comparison of our observations on cross-sections near Artemovsk and the published coal mine logs of Artemovsk Geological Survey. The Moscovian of the Donets basin is equivalent to the uppermost Westphalian B and the Westphalian C and D of western Europe. In the Donets basin, the Moscovian forms a second-order sequence as in the Moscow basin, that can be subdivided into four third-order sequences, subdivided into fourth-order sequences. The upper Bashkirian shows two fourth-order sequences. The Vereian exhibits two fourth-order sequences. The Kashirian shows four fourth-order sequences. The Podolskian offers eight fourth-order sequences. The Myatchkovian presents four fourth-order sequences. These sequences begin with an erosive base and show a succession of elementary sequences with fluvial sandstone, coal seam, limestone and deltaic facies. The fluvial sandstone corresponds with an aggradation period, the coal and the limestone with a transgressive period and the deltaic facies with a progradation period. A decrease of the sandstone thickness and an increase of the marine deposits that are transgressive and regressive upwards are observed from the base to the top of sequences. These fourth-order sequences present a higher spatial amplitude than the third-order sequence and obscure these sequences. The second-order sequence equivalent to the Moscovian shows a lowstand system tract with more fluvial sandstone in the lower part of the Vereian, a transgressive system tract in the upper part of the Vereian, Tsinskaya and Kashirian, a maximum flooding period during the Podolskian and lower part of the Myatchkovian with more marine facies and a highstand system tract in the upper part of the Myatchkovian with more lagoonal and swampy palaeoenvironments. The sequences are controlled by the regional tectonic subsidence in the graben and the uplift of the horsts and/or by eustasy with either a plate-tectonic or a glacial origin. Other investigations, particularly radiometric dating, will be useful for solving this problem.

Sequence stratigraphy and correlation of late Carboniferous and Permian in the CIS, Europe, Tethyan area, North Africa, Arabia, China, Gondwanaland and the USA

Abstract Sequence stratigraphy was used to correlate the depositional chronology during Permo–Carboniferous time in various sedimentary basins of Gondwanaland, western Europe, eastern Europe, Tethyan area, North Africa, Arabia, China, and North America. During late Carboniferous and Permian, eleven second-order sequences (SOS) were recognised throughout the whole area. The sequence SI is Serpukhovian pp, Namurian A pp and Chesterian. The sequence SII is Serpukhovian pp–Bashkirian pp, Namurian A pp-B-C–Westphalian A–B pp and Morrowan. The sequence SIII is late Bashkirian–Moscovian, Westphalian B pp-C-D and Atokan–Desmoinesian. The sequence SIV is Kasimovian, early Stephanian and Missourian. The sequence SV is Gzhelian–Orenburgian, late Stephanian and Virgilian. The sequence SVI is Asselian, Autunian and Nealian. The sequences SVII–IX are Saxonian, Sakmarian–Artinskian–Kungurian and Leonardian–Hessian–Cathedralian. The sequences SX–XI are Guadalupian and Lopingian. Depending on the regional setting, different relationships exist between marine transgression and the respective effects of tectonics and of sea-level changes: in western Europe, effects of the glacial processes in Gondwanaland are partly balanced by the late compression in the Hercynian belt during Moscovian. Eastern Europe, Tethyan area, North Africa, China, and North America show a good correlation between glacial (ice melting) processes in Gondwanaland and the intensity of the transgression which is increased by the westward progradation of the orogeny in Urals and Appalachians. In Arabia, Tunisia and Tethyan area, the impact of the Neotethys opening is obvious from the Artinskian and mainly during the late Permian.

Palaeozoic Reefs and Bioaccumulations: Climatic and Evolutionary Controls.

The geological record contains a fascinating diversity of reefs and shell accumulations. As my other biosedimentary structures, their facies characterization requires careful observation at outcrop and sample scale, and in thin-section to provide information about the global geometries, fabrics and textures respectively. This collection of papers encompasses the breadth of sedimentary geometries and facies displayed by Palaeozoic reefs, shell accumulations, and transitional composite deposits. The definition of reefs and shell concentrations has given rise to variations in nomenclature. The papers in this volume cover specific problems regarding the nomenclature and facies characterization of reefs, shell accumulations and transitional composite deposits. However, rather than attempt a complete revision of terms, the authors have touched on some of the important issues at this stage of development in the field: the main climatic, environmental and evolutionary factors that controlled the Palaeozoic development of shell accumulation and reefs.

NEW SEM OBSERVATIONS OF KERIOTHECAL WALLS: IMPLICATIONS FOR THE EVOLUTION OF FUSULINIDA

This study presents new scanning electron microscopy (SEM) observations of Paleozoic foraminifera. It focuses especially on the wall of three Fusulinida, Sakmarella moelleri, Paraskinnerella skinneri, and Taiyuanella furoni, that belong to the Schwagerinoidea, which are fusulinids with keriothecal test walls. In addition, Eostaffella sp. is investigated as an example of the microstructure of the microgranular imperforate tectum. The fillings of the keriothecal alveoles of Sakmarella, Paraskinnerella, and Taiyuanella yield diverse, characteristic flower-like structures that indicate a gradual evolution of the microstucture of the tests. Sakmarella and Paraskinnerella have flowers with a narrow center, and Taiyuanella has a larger center. The true keriothecal structure, described, for example, in Triticites, is distinguished from these structures by simply filled alveoles. The term ‘‘anthotheca’’ is introduced for the structure with narrow-centered flowers. It can be distinguished from the large-centered flower structure identified as Zhuang’s (1989) stalactotheca. Following a literature review of previous work on keriothecal structures, several morphofunctional hypotheses are discussed, including the housing of symbiotic algae or cyanobacteria, which leads to the new interpretation that the flowers of the antho- and stalactothecal structures are induced by algal endosymbionts. In addition, we discuss the monophyly of keriothecal fusulinids. The transition from diaphanothecal to keriothecal forms recognized since Thompson (1964) is reinterpreted in terms of relationships with symbiotic algae or cyanobacteria. The Schwagerinoidea constitute an important group in understanding the evolution of larger foraminifera in the late Paleozoic.

Discovery of Triassic fossils at Bukit Chuping, in Gunung Sinyum area, and at Kota Jin, Peninsular Malaysia

Abstract Some poorly fossiliferous limestones of Peninsular Malaysia, previously considered to be Permian, have yielded Triassic algae and foraminifera; these fossils, although not abundant, clearly indicate a Triassic (Ladinian-Carnian) age. The assemblages resemble others known in the Triassic of Europe and Turkey. A new foraminiferan genus and species. Malayspirina fontainei , is described. This new genus is a survivor of the Upper Paleozoic family Forschiidae.

Late Serpukhovian (Namurian A) microfacies and carbonate microfossils from the Carboniferous of Nötsch (Austria)

SummaryThe Carboniferous of Nötsch (Austria), divided into Erlachgraben, Badstub and Nötsch Formations, is composed of a thick sequence of dominantly siliciclastic deepsea sediments. Intercalated marly and silty limestones in the upper Erlachgraben Formation consist of bioclastic wackestones and algal wackestones/packstones which contain a diverse fossil assemblage of formainifers, algae and pseudo-algae. These microfossils are accurately described and documented, and three species of algae are established:Principia fluegeli n. sp.,Paraepimastopora noetschensis n. sp., andNanopora pseudofragilissima n. sp.Based on the occurrence of both important species of the foraminifers Lasiodiscoidea (Howchinia gibba andEolasiodiscus dilatatus), and also on the presence ofEndothyranopsis plana, of the lastEarlandia ex. gr.vulgaris and of the firstEostaffella exp gr.postmosquensis, the upper Erlachgraben Formation is dated as late Serpukhovian (goniatite biozone E 2 of the Namurian A; Arnsbergian stage, corresponding to the Zapaltyubinsky of the standard Russian sequence; foraminiferal biozones 18 or Cf 7 of Belgium, or Cf 16 of the Donbass).Compared to the Pyrenees and the Donbass region, the algal flora of the Carboniferous of Nötsch seems to be relatively endemic. Algae and foraminifers originally inhabited a shallow carbonate ramp and were transported and redeposited in a deep-water environment by gravity flows. The formainifers most probably migrated from the Donbass region along the shelf of a narrow seaway to Nötsch.

Biostratigraphie par fusulines des calcaires carbonifères et permiens de San Salvador Patlanoaya (Puebla, Mexique)

Resume Les calcaires de la Formation San Salvador Patlanoaya (Mexique) livrent six biozones a fusulines. Les principaux genres permettant de dater sont des Triticites et des Kansanella du Missourien et du Virgilien inferieur (Carbonifere superieur), des Pseudofusulina et des Rugosochusenella du Wolfcampien (Permien inferieur) et des Paraskinnerella et des Skinnerella du Leonardien moyen. Les differentes especes de chacun des genres sont decrites et illustrees: Triticites sp. 1, Triticites burgessae, Triticites milleri, Triticites piloncillosensis, Triticites acutuloides, Triticites oryziformis (=T. homecreekensis), Triticites moorensis, Triticites primarius, Triticites aff. confertoides, Triticites aff. lepidus, Kansanella neglecta, Rugosochusenella emend. (=Pseudochusenella), Rugosochusenella gregaria, Skinnerella emend., Skinnerella imlayi (=S. robusta), Paraskinnerella skinneri (=P. leonardensis) .

Middle permian (midian) foraminiferal assemblages from the batain plain (Eastern Oman): Their significance to neotethyan paleogeography

Exceptionally rich Permian fusulinid assemblages, varying in age from Yakhtashian to Dzhulfian, were found in reworked limestone blocks from conglomerates of the Aseelah Unit, recently defined in the Batain Plain and dated possibly as Upper Triassic. This paper only deals with the Middle Permian, Midian (= Capitanian) microfaunas from the conglomerates. The Aseelah Unit is found associated with the Triassic Sal Formation, tectonically overlying the Qarari Unit, and is dated as Middle to Late Permian based on ammonoid assemblages and conodonts. The boulders of the Aseelah Unit are composed of exclusively Permian skeletal limestones in a sandy matrix; the limestones were deposited on a shallow marine shelf environment from the southern Neotethys. The Qarari Unit is interpreted as a hemipelagic series deposited on the distal slope of the Arabian carbonate platform. The Midian foraminifers from the Batain Plain are similar to some assemblages of Transcaucasia, of the Abadeh area (Iran), of SW Turkey (Taurus Mountains), and some, especially the Neoschwagerinidae, exhibit affinities with microfaunas of the eastern Tethys terranes of Japan. However, similar Neoschwagerinid assemblages were not found in any significant area of the Arabian Peninsula (Oman Mountains, Huqf-Haushi area, and Khuff area).

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.