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1

Middle/Upper Devonian brachiopod shell concentrations from the intra-shelf basinal carbonates of the Holy Cross Mountains (central Poland)

Skompski S., Baliński A., Szulczewski M., Zawadzka I.

Acta Geologica Polonica

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2018

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Vol. 68, no. 4

607--633

EN

A huge isolated accumulation, more than 3 m thick and 10 m wide, of densely packed, uncrushed brachiopods has been found in Józefka Quarry within the Middle/Upper Devonian Szydłówek Beds deposited in a relatively deep environment of an intrashelf basin (Kostomłoty facies zone, western Holy Cross Mountains, Poland). The low-diversity assemblage is strongly dominated by the atrypide Desquamatia globosa jozefkae Baliński subsp. nov. and, to a lesser degree, by the rhynchonellide Coeloterorhynchus dillanus (Schmidt, 1941), which constitute 72.8% and 22.1% of the fauna, respectively. Less frequent are specimens representing the genera Hypothyridina, Schizophoria and Phlogoiderynchus. According to the conodont fauna found within the coquina bed, the stratigraphic position of the shell accumulation is close to the Givetian/ Frasnian boundary. The brachiopods are associated with numerous crinoids and less frequent bryozoans, receptaculitids (Palaeozoic problematica), sponges and solitary corals. Although it is difficult to entirely exclude the autochthonous nature of the brachiopod coquina member, its allochthonous origin and redeposition of the brachiopod shells to the deep basin by gravity flows is much more probable. Such conclusion is supported by the following facts: (1) the position of the complex in a succession of deep-marine basinal facies impoverished in oxygen; (2) its lateral thinning-out and composite internal stratification; (3) the lensshaped geometry of the coquina bed in the section perpendicular to the bedding dip; (4) high variability of the sediments preserved within the shells; and (5) the preferred orientation of the shells. The brachiopods mixed with crinoidal debris were probably transported by low-velocity, high-density, gravity-induced debris flows. Lack of fossils typical of the Middle Devonian shallows, such as massive stromatoporoids, amphiporoids and tabulates, indicates that the source area of the bioclastic material was not located in the shallowest part of the shelf, but most probably on a submarine sea-mount to the north of present-day Józefka, as suggested by earlier investigators. The triggering mechanism of the allochthonous deposition was an earthquake rather than storm activity. The enormous thickness of the brachiopod complex is probably caused by the sinking of bioclastic material, transported in succeeding depositional multi-events, in a soft, muddy bottom, typical of the Szydłówek Beds deposition.

2

Selected Oxfordian brachiopods from Zalas (Cracow Upland, Poland)

Radwańska U.

Acta Geologica Polonica

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2017

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Vol. 67, no. 3

433--440

EN

Small brachiopods of the families Craniidae Menke, 1828 and Thecidellinidae Elliott, 1958 were selected from the Oxfordian sequence which lies transgressively upon a Variscan rhyodacite laccolite exposed at Zalas in the Cracow Upland, southern Poland, a site which is well-known due to various kinds of ubiquitous fossils. The craniids include three species: Craniscus bipartitus (Münster in Goldfuss, 1837), Craniscus tripartitus (Münster in Goldfuss, 1837) and Craniscus antiquior (Jelly, 1843), and the thecidellinids – two species: Rioultina zalasensis sp. nov. and Rioultina wapiennensis Krawczyński, 2008. The species described herein indicate tropical or subtropical waters, and a moderately (?) deep character of the sea basin at Zalas.

3

Late Ordovician palaeogeography and the positions of the Kazakh terranes through analysis of their brachiopod faunas

Popov L. E., Cocks L. R. M.

Acta Geologica Polonica

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2017

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Vol. 67, no. 3

323--380

EN

Detailed biogeographical and biofacies analyses of the Late Ordovician brachiopod faunas with 160 genera, grouped into 94 faunas from individual lithotectonic units within the Kazakh Orogen strongly support an archipelago model for that time in that area. The Kazakh island arcs and microcontinents within several separate clusters were located in the tropics on both sides of the Equator. Key units, from which the Late Ordovician faunas are now well known, include the Boshchekul, Chingiz-Tarbagatai, and Chu-Ili terranes. The development of brachiopod biogeography within the nearly ten million year time span of the Late Ordovician from about 458 to 443 Ma (Sandbian, Katian, and Hirnantian), is supported by much new data, including our revised identifications from the Kazakh Orogen and elsewhere. The Kazakh archipelago was west of the Australasian segment of the Gondwana Supercontinent, and relatively near the Tarim, South China and North China continents, apart from the Atashu-Zhamshi Microcontinent, which probably occupied a relatively isolated position on the south-western margin of the archipelago. Distinct faunal signatures indicate that the Kazakh terranes were far away from Baltica and Siberia throughout the Ordovician. Although some earlier terranes had joined each other before the Middle Ordovician, the amalgamation of Kazakh terranes into the single continent of Kazakhstania by the end of the Ordovician is very unlikely. The Late Ordovician brachiopods from the other continents are also compared with the Kazakh faunas and global provincialisation statistically determined.

4

Brachiopods and stratigraphy of the Upper Devonian (Frasnian) succession of the Radlin Syncline (Holy Cross Mountains, Poland)

Baliński A., Racki G., Halamski A. T.

Acta Geologica Polonica

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2016

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Vol. 66, no. 2

125--174

EN

The lower part of the Frasnian succession in the Radlin Syncline (Kielce–Łagów Synclinorium, southern region of the Holy Cross Mountains), in the two studied successions: Józefka at Górno and (for the first time) Radlin, consists of the rhythmic marly Szydłówek Beds, the fossil-rich limestones of the Wietrznia Beds (locally) and the atypically developed, calcareous Kostomłoty Beds. The carbon isotope chemostratigraphic pattern overall corresponds well to the global Early–Middle Frasnian biogeochemical perturbation, even if the major punctata positive excursion is only fragmentarily recorded in the Kostomłoty intrashelf basin. Two brachiopod assemblages are abundantly represented in both sections: the Phlogoiderhynchus polonicus Assemblage, typical of the Szydłówek Beds, and the Biernatella lentiformis Assemblage, limited to the middle part of the Wietrznia Beds. Both are highly dominated by the index species. Twenty nine lower Frasnian brachiopod species (Craniida – 1 species, Strophomenida – 1, Productida – 2, Protorthida – 1, Orthida – 5, Pentamerida – 1, Rhynchonellida – 4, Atrypida – 4, Athyridida – 3, Spiriferida – 4, Spiriferinida – 3) are described from the Szydłówek and Wietrznia Beds. Seven new species are introduced: Skenidioides cretus Halamski sp. nov., Biernatium minus Baliński sp. nov., Monelasmina montisjosephi Baliński sp. nov., Atryparia (Costatrypa) agricolae Halamski and Baliński sp. nov., Davidsonia enmerkaris Halamski sp. nov., Leptathyris gornensis Baliński sp. nov., and Echinocoelia parva Baliński sp. nov. Davidsonia enmerkaris Halamski sp. nov. is intermediate between Davidsonia Bouchard-Chantereaux, 1849 and Rugodavidsonia Copper, 1996 and is the youngest known representative of the suborder Davidsonioidea Copper, 1996. Skenidioides cretus Halamski sp. nov. is the last representative of the genus. Statistical investigation of a large sample of Spinatrypina (Exatrypa) explanata did not confirm the existence of two dimorphic forms, coarse- and fine-ribbed. The high-diversity Biernatella lentiformis Assemblage is quite dissimilar to coeval brachiopod assemblages described heretofore from the Holy Cross Mountains region. It is interpreted as consisting of mostly parautochthonous dwellers of deep-slope muddy habitats and a local, occasionally storm-agitated, intra-basin brachiopod-crinoid-coral shoal. The fauna was adapted probably to cooler and nutrient-poor waters during an initial phase of the severe carbon cycle perturbation.

5

Review of the Ordovician stratigraphy and fauna of the Anarak Region in Central Iran

Popov L. E., Hairapetian V., Evans D. H., Ghobadi Pour M., Holmer L. E., Baars C.

Acta Geologica Polonica

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2015

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Vol. 65, no. 4

403--435

EN

The Ordovician sedimentary succession of the Pol-e Khavand area, situated on the northern margin of the Yazd block, has important differences from those in other parts of Central Iran. It has been established that the presumably terminal Cambrian to Lower Ordovician volcano-sedimentary Polekhavand Formation, exposed in the Pol-e Khavand area, has non-conformable contact with greenschists of the Doshakh Metamorphic Complex. The succeeding, mainly siliciclastic Chahgonbad Formation contains low to moderately diverse faunal assemblages, including brachiopods, cephalopods, trilobites and tentaculitids. The Darriwilian age of the lower part of the formation is well established by the co-occurrence of brachiopod genera Camerella, Phragmorthis, Tritoechia and Yangtzeella. The associated rich cephalopod fauna is different from the Darriwilian cephalopod associations of the Alborz terrane and may show some affinity with warm water faunas of North China and South Korea. It is likely that the Mid Ordovician fauna recovered from the lower part of the Chahgonbad Formation settled in the area sometime during a warming episode in the late Darriwilian. By contrast the low diversity mid Katian brachiopod association includes only three taxa, which occur together with the trilobite Vietnamia cf. teichmulleri and abundant, but poorly preserved tentaculitids questionably assigned to the genus Costatulites. This faunal association bears clear signatures linking it to the contemporaneous cold water faunas of the Arabian, Mediterranean and North African segments of Gondwana. Four brachiopod species recovered from the Chahgonbad Formation, including Hibernodonta lakhensis, Hindella prima, Lomatorthis? multilamellosa and Yangtzeella chupananica are new to science.

6

Do the available data permit clarification of the possible dependence of Palaeozoic brachiopod generic diversity dynamics on global sea-level changes? A viewpoint

Ruban D. A.

Geologos

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2014

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Vol. 20, No. 3

215--221

EN

At a glance, progress in palaeontology and eustatic reconstructions in the past decade permits to prove or to disprove the possible dependence of Palaeozoic brachiopod generic diversity dynamics on global sea-level changes. However, the available diversity curve is of much lower resolution than the eustatic curve. This problem can be resolved by decreasing the resolution of the latter. The other restriction linked to the chronostratigraphical incompatibility of the available data allows to focus on the Middle Palaeozoic only. A series of mass extinctions and other biotic crises in the Silurian-Devonian does not allow to interpret correctly the results of direct comparison of the brachiopod generic diversity dynamics with global sea-level changes. With the available data, it is only possible to hypothesize that the eustatic control was not playing a major part in diversity dynamics of Middle Palaeozoic brachiopods. The resolution of the stratigraphic ranges of Palaeozoic brachiopods should be increased significantly, and these ranges should be plotted against the most up-to-date geologic time scale. Until this task will be achieved, it is impossible to judge about the existence of any dependence (either full or partial) of the Palaeozoic brachiopod diversity dynamics on global sea-level changes.

7

The first Jurassic thecideide brachiopods from the Middle East : A new species of Moorellina from the Upper Callovian of Hamakhtesh Hagadol, southern Israel

Krawczyński C., Wilson M.

Acta Geologica Polonica

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2011

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Vol. 61, no. 1

71-77

EN

The Matmor Formation is a set of late Callovian marls and limestones exposed in the Matmor Hills, Hamakhtesh Hagadol, southern Israel. It was deposited during a regional transgression which produced patch reefs across a shallow carbonate platform in this area. The thecideide brachiopods described here were part of a diverse sclerozoan community which encrusted the calcareous surfaces of sponges and corals. These brachiopods represent a new, very small species of Moorellina and the only thecideide brachiopod found in the Jurassic deposits of the Middle East. A gall-like structure interpreted as the trace of the parasitic (ascothoracid?) infestation has been recorded in one specimen of Moorellina negevensis sp. nov.

8

New data on the stratigraphy of the Ordovician at Pobroszyn, Holy Cross Mts., Central Poland

Bednarczyk W., Stempień-Sałek M.

Acta Geologica Polonica

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2011

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Vol. 61, no. 1

47-58

EN

New biostratigraphic and lithostratigraphic data are presented for the tectonically reduced Ordovician succession at Pobroszyn in the Łysogóry region of the Holy Cross Mountains, central Poland. Only some of the chronostratigraphic units known from the Łysogóry region can be recognized in this section. However, based on lingulate brachiopods, conodonts, acritarchs and chitinozoa, the units present may be referred to the Late Tremadoc, Late Arenig, Early Lanvirn, Late Lanvirn, Early Caradoc and to the Middle Caradoc and Ashgill. New lithostratigraphic units are established in the lower part of the Ordovician of the Pobroszyn section: the Opatówka Mudstone/Sandstone Formation (?Late Tremadoc) and the Pobroszyn Sandstone Formation (Late Arenig). Three species of lingulate brachiopods are described, of which two are new: Myotreta anitae and Eoconulus lilianae. The conodonts and acritarchs are illustrated and briefly discussed.

9

The Upper Oxfordian (Jurassic) thecideide brachiopods from the Kujawy area, Poland

Krawczyński C.

Acta Geologica Polonica

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2008

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Vol. 58, no. 4

395-406

EN

Thecideide brachiopods from the slope facies of a sponge-cyanobacterial bioherm exposed in the Wapienno and Bielawy quarries (Kujawy, Poland) are described. Numerous specimens were found in the upper part of the section, in the Hauffianum-Planula Subzones of the Oxfordian, and constitute the first record of these brachiopods from the Jurassic deposits in the area. Two species: Rioultina wapiennensis sp.nov. and Neothecidella ulmensis QUENSTEDT, 1858, are described, the first being the only representative of the genus Rioultina found in Poland. Excellent preservation of some specimens enabled recognition of details of their internal morphology usually inaccessible in fossil material, including features associated with reproduction and the development of the brachidium. Study of relatively large numbers of thecideides still cemented to the substrate, together with analysis of the associated fauna, allowed the reconstruction of aspects of their ecology.

10

The Devonian of Western Karakorum (Pakistan)

Gaetani M., Mawson R., Sciunnach D., Talent J.

Acta Geologica Polonica

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2008

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Vol. 58, no. 3

261-285

EN

Devonian rocks crop out in several thrust sheets in the sedimentary belt of North-Western Karakorum, both to the south and to the north of the Reshun Fault. Gently metamorphosed Devonian dolostones and volcanics are also present in the Tash Kupruk Zone north of the thrust sheet system. The most complete succession is found in the Karambar Thrust sheet where dolostones and recrystallized limestones (Vandanil Formation) lie above the black shales and siltstones of the Baroghil Group. The age of the Vandanil Formation is poorly defined, approximating latest Silurian or earliest Devonian at its base and proven to be Pragian in the 4th of its 5 lithozones. The overlying Chilmarabad Formation is divided into two members. The lower member is a mixed siliciclastic-carbonate package, present in most southern and western thrust sheets. The upper member is ubiquitous; it consists of dolostones, often stromatolitic. The calcareous part of the Tash Kupruk Zone consists of similar facies. The carbonate flats of the Chilmarabad Formation display a trend towards emersion towards the top, and are overlain, with regional unconformity, by the basal unit of the Shogram Formation. The base of the latter consists of arenite and fine conglomerate (deposited in an alluvial setting) overlain by alternating marine bioclastic limestones and litharenites with one or two coral bafflestones in the middle to upper part. The age of the lowermost part of the Shogram Formation is Givetian, extending through the Frasnian and seemingly into the Famennian, but the last is poorly documented (contrasting with the classic Shogram and Kuragh sections of Chitral); it reflects a return to fine terrigenous input. The inferred palaeogeography accords with the Northern Karakorum having been part of the Gondwana margin during the Devonian. Awide, mostly calcareous platform, characterised extensive areas of the Karakorum, Central Pamir, Badakhshan and, in a minor way, Central Afghanistan (Helmand Block). The sandstone petrography suggests that clastics polluting the carbonates originated from erosion of a pre-existing sedimentary cover. During the Givetian a first rifting episode, possibly echoing the opening of an ocean to the east, affected the whole area,with volcanic outpourings in the rifts, while eroding shoulders fed the basins, though never extending as deep as the crystalline basement. A minor volcanic input is also recorded. The tectonic pulse almost ceased during the Frasnian, gradually resuming towards the end of the Devonian.

11

Selected benthic faunas from the Devonian of the Ardennes: an estimation of palaeobiodiversity

Hubert B.

Acta Geologica Polonica

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2007

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Vol. 57, no. 2

223-262

EN

A survey of the principal benthic faunas from the Devonian of the Ardennes is presented. The [alfa] diversity is very high (707 species, including 138 species of stromatoporoids, 113 species of tabulates, hydroids and chaetetids, and 456 species of brachiopods). Analysis of their distribution through time indicates two brachiopod diversity peaks (Emsian/Eifelian and Frasnian), a single stromatoporoid diversity peak (Givetian), and no clear peak of tabulate corals (with the highest diversification during the Eifelian.Frasnian). The highest diversity of bioconstructors in the Givetian correlates with a decrease in brachiopod diversity. Changes in the vertical distribution of the faunas are correlated with the facies development: the development of carbonates correlates with the abundance of stromatoporoids and tabulates, while brachiopods were most abundant before and after the peak of carbonate development. Bioconstructors are absent (or nearly absent) in siliciclastic facies.

12

Zeillerid brachiopods from Upper Jurassic olistholiths (South Carpathians, Romania)

Lazar I., Sandy M.

Volumina Jurassica

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2006

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Vol. 4, no. 1

238-239

EN

The Lower Cretaceous formations that crop out on the eastern slope of the Bucegi Mountains comprise some beds containing the Upper Jurassic limestone blocks, described by Patrulius (1954) as olistholiths. These olistholiths are well represented in outcrops near Sinaia, Moroieni, Cernatu, Purcareni. The Middle and Upper Jurassic deposits are recognized in the southern part of the Purcareni locality. The Middle Jurassic deposits include here sandstones, calcarenites and marls with Posidonia alpina, and the Upper Jurassic - the reef limestones. In the Purcareni-Zizin-Tirlungeni area, the Lower Cretaceous (Barremian-Aptian) deposits are conglomerates, breccias, sandstones and marls of the Piscul cu Brazi Formation. This formation includes several Upper Jurassic reef limestone blocks, each of them of a volume around 100-200 m3. The Piscul cu Brazi Formation belongs to the sedimentary cover of the Ceahlau Nappe of the External Dacides of the Carpathian Orogen. The Outer (External) Dacides represent a group of units, which proceed from a Jurassic - Lower Cretaceous paleo-rift, developed within the European continental margin. The olistholiths, especially those from Purcareni, contain a very rich reef assemblage with corals, pachiodont bivalves, gastropods, brachiopods, galatheids, decapods crustaceans, crinoids and echinoids. Murgeanu et al. (1959) and Graf (1975) summarized the previous researches on the geology and palaeontology of this area. The brachiopods are very abundant (a large number of individuals in different growth stages) within this benthonic assemblage, represented mainly by Zeillerina sp. and other terebratulids, including large specimens (2 cm length) of "Terebratulina". The preservation of Zeillerina shells is very good. Shell endopunctation is well preserved. The internal features of a few specimens have been investigated and are consistent with those of the typical representatives of Zeillerina. These include a pedicle collar and dental lamellae in the ventral valve, a median septum and horizontal hinge plates in the dorsal valve.

13

The Pliensbachian/Toarcian boundary in the Almonacid de la Cuba section (Iberian Range, Spain)

Goy A., Comas-Rengifo J., Gomez J., Gonzales J., Herrero C., Palencia A., Perilli N., Rodrigo A.

Volumina Jurassica

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2006

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Vol. 4, no. 1

164-166

EN

The Almonacid de la Cuba section, representative of the Pliensbachian-Toarcian transition in the Iberian Range (Fig. 1), is reviewed. It is an expanded section where no important discontinuities have been detected. Four successive assemblages of ammonites, which are characterized by the presence of Pleuroceras (BH14-CU14), Canavaria (CU16-CU32), Dactylioceras (E.) (CU35.2-CU44) and Dactylioceras (O.) (CU44-CU87), are distinguished. The Pliensbachian/Toarcian boundary is located at the base of level CU35.2 with the first record of Dactylioceras (Fig. 2). These assemblages are mainly constituted by taxa typical of the NW European Province, such as Pleuroceras, Dactylioceras (O.) and P. paltum. However, frequent Mediterranean Province taxa such as Emaciaticeras, Canavaria, Lioceratoides, Neolioceratoides, Dactylioceras (E.) and P. madagascariense, are also recorded. In the Tenuicostatum Zone, dactylioceratidae are dominating with respect to harpoceratinae. In the Mirabile Subzone, species of Dactylioceras (E.) are coexisting with P. paltum. Brachiopods show two successive assemblages. The lower one is composed generally of the Pliensbachian taxa and the upper assemblage includes more endemic taxa. Coinciding with the Early Toarcian OAE, almost all these species disappeared at the end of the Tenuicostatum Chron. Foraminiferal assemblages are rich and diversified. Calcareous hyaline taxa are dominated by suborder Lagenina, agglutinated foraminifera are scarce, the suborders Spirillinina and Miliolina are represented by few specimens and taxa, and specimens of Robertinina have been recovered throughout the whole stratigraphic interval. The main biostratigraphical foraminiferal events can be recognized and compared with other sections of the Iberian Range and with another ones of selected NW European Basins. Ostracod assemblages of the Spinatum Zone are dominated by healdiids and cytheraceans, which decrease at the base of the Tenuicostatum Zone, where the cypridaceans are better represented. In the Semicelatum Subzone, coinciding with the disappearance of the healdiids, the cytheraceans become dominants.Calcareous nannofossils assemblages are rich and well preserved. This allowed locating precisely the biochronostratigraphical position of the main markers and events and comparing them with these recorded in other basins of Western Tethys. A magnetic polarity column for the Pliensbachian/Toarcian boundary has been constructed on the basis of the polarities of the 2C Component (Fig. 2). The lower boundary of the Toarcian is located within the R2 magnetozone. A relatively large magnetozone N3 of normal polarity is located within the Tenuicostatum Zone.

14

Stratigraphic distribution of brachiopods in the Lower Jurassic – Middle Jurassic transition of the Lusitanian Basin (Portugal) and a proposal of biozonation

Andrade B., Joral F., Henriques M.

Volumina Jurassica

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2006

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Vol. 4, no. 1

143-143

EN

A detailed revision of the brachiopods of the Lower-Middle Jurassic transition in the Lusitanian Basin (Andrade 2006) has enabled the establishment of the stratigraphical distribution of this fauna. More than 2,000 specimens were collected at 11 sections throughout the basin, including the Bajocian GSSP in Murtinheira (Cabo Mondego). In all, 24 species, belonging to 14 genera, have been recognized along a stratigraphical interval that includes the Upper Toarcian, the Aalenian, and the Lower Bajocian. The Toarcian associations are characterized by species also recorded in neighbouring basins, such as Stroudithyris stephanoides, Sphaeroidothyris vari, Pseudogibbirhynchia bothenhamptonensis and Soaresirhynchia renzi; as well as species endemic to the Lusitanian Basin, such as Choffatirhynchia alcariensis, Nannirhynchia delgadoi, N. cotteri, Praemonticlarella conimbriguensis, Neozeilleria duartei and Pamirorhynchia(?) jorali. This mixed palaeobiogeographical character persists in the Aalenian, in which the associations include, together with widely distributed species such as Neozeilleria anglica, Pseudogibbirhynchia mutans or Lophrothyris withingtonensis, other species known in neighbouring basins, such as Sphaeroidothyris uretae and Neozeilleria sharpei, and other species recorded only in the basin, such as Soaresirhynchia minor, S. murtinheirensis and Sphaeroidothyris henriquesae. In the Lower Bajocian, excluding Loboidothyris perovalis, only endemic species are present (belonging mainly to endemic genera), such as Lusitanina bituminis, Stroudithyris choffati, Lusothyris atlantica and Mondegia limica. The interpretation of these distributions also enables to propose a brachiopod based biozonation for the studied interval. Three zones have been erected: 1. the Renzi Zone, for the Upper Toarcian, with two subzones: Renzi and Duartei; 2. the Anglica Zone, that ranges from the Aalensis Biochronozone of the Toarcian to the base of the Bajocian. It has been subdivided in 3 subzones: Nuskae, Anglica and Uretae; 3. the Choffati Zone, which comprises the main part of the Discites, Laeviuscula and Sauzei biochronozones, with two subzones: Bituminis and Limica; 4. this proposal of biozonation can be correlated with other established in neighbouring basins, such as the Iberian Range in Spain or the French Basins.

15

Oyster and brachiopod stable isotopes across the Triassic/Jurassic boundary and in the Early Jurassic

Korte C., Hesselbo S., Jenkyns H., Dietl G., Dulai A., Vörös A.

Volumina Jurassica

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2006

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Vol. 4, no. 1

289-289

EN

Oxygen and carbon isotope values have been obtained from oysters for the Triassic/Jurassic boundary section at Lavernock Point (Wales), and from brachiopods and oysters for different Hettangian, Sinemurian and Pliensbachian localities of South Germany and Hungary. Low-Mg-calcite brachiopods and oysters are particularly suitable for such studies because this carbonate phase is the most resistant to diagenetic alteration. Nevertheless, all fossils have been screened by chemical and optical techniques (optical microscope, scanning electron microscopy, trace element analyses) to evaluate the isotope data for diagenetic change, and only samples with Mn content less than 250 ppm and Sr content more than 400 ppm, complemented by well preserved textures under SEM, were considered in this study. For the Triassic/Jurassic boundary (TJB) the carbon isotope values are at about 2.5‰ in the lower Langport Member, increase to 4.5‰ in the lowest Blue Lias and decrease subsequently to 1.5‰ just below the Planorbis Zone. The data remain low with variations between 1.5 and 2.5‰ up to the Liassicus Zone. These results correspond to the organic carbon isotope trend for the Triassic/Jurassic boundary section at St Audrie's Bay (Hesselbo et al. 2002). Oxygen isotope values increase from -0.5‰ in lower Langport Member to 0‰ at the base of the Blue Lias, decrease in the Blue Lias down to -1.5‰ just below the Planorbis Zone and change in parallel with the organic and inorganic carbon-isotope trends. The δ ¹ ⁸O values indicate decreasing seawater temperature with increasing δ ¹ ³C in the Langport Member and increasing water temperatures of about 6°C in the lower Blue Lias. The distinct warming trend occurred during the "main" TJB negative excursion. Carbon and oxygen isotope values from Hettangian, Sinemurian and Pliensbachian brachiopods and oysters, as well as from some complementary belemnites, show similar values and trends compared to the data compilation by Jenkyns et al. (2002). Carbon isotope values are between 1 and 2‰ in the Hettangian and Early Sinemurian followed by an increase of about 1‰ during the Sinemurian, a nearly 3‰ decrease in the Early Pliensbachian and higher δ ¹ ³C values (˜2.5‰) in the later Pliensbachian.

16

Importance of the Mellala section (Traras Mountains, NW Algeria) for the correlations of the Pliensbachian/Toarcian boundary

Elmi S., Marok A., Sebane A., Almeras Y.

Volumina Jurassica

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2006

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Vol. 4, no. 1

158-160

EN

The Mellala profile has a great importance as international reference section because it exposes a continuous and very fossiliferous record through the Pliensbachian/Toarcian boundary (Fig. 1). This boundary is situated within the hemipelagic Bayada Formation (alternating marls and marly limestones) yielding Zoophycos and Steinmannia bronni (shells and “filaments”). It has been deposited in a small subbasin (umbilicus) that was strongly subsiding and deepening during the Late Pliensbachian and the Early Toarcian. The sequence evolution is globally stratodecreasing and deepening upward until the middle part of the Early Toarcian (early Levisoni Zone). The Bayada Fm. begins in the Upper Domerian. The Emaciatum Zone is divided in two parts. The lower (Solare Subzone, thickness 8 m) is documented by several Pleuroceras solare (Phillips) occurring alone in the lower part of the subzone, but associated with Emaciaticeras upwards. Brachiopods include Phymatothyris kerkyrae (Renz) and Quadratirhynchia quadrata Buckman. The upper part (Elisa Subzone) is characterized by Tauromeniceras elisa (Fucini), Canavaria finitima (Fucini), Paltarpites bettonii (Fucini) associated with numerous P. kerkyreae (Renz) and rare Lobothyris punctata (Sowerby). The main part of the brachiopod assemblage consists of small sized species: Nannirhynchia pygmoea (Davidson), Koninckella liasina (Davidson) and Cadomella cf. moorei (Davidson). This is the Koninckella fauna (previously named Leptaena fauna). Leioceratoides gr. serotinus (Bettoni) has been found in the upper part of the Elisa Subzone. The base of the lowermost Toarcian (Mirabile Subzone) is marked by a decimetric bed (n° 38) with Paltarpites paltus (Buckman) but without Eodactylites at the present state of the research. The following calcareous bed (n° 40) has yielded several Dactylioceras (Eodactylites) polymorphum (Fucini) and D. (E.) pseudocommune (Fucini). The brachiopods are represented by Liospiriferina subquadrata (Seguenza), Lobothyris sp. and the Koninckella fauna: C. moorei, N. pygmoea and K. liasina. Upwards, the Eodactylites becomes abundant at 10 to 12 m, especially in the bed n° 44. At 3.50 m under the top of the subzone, a marker-bed (48) corresponding to a lenticular level of bioclastic quartziferous limestones occurs. The overlying 15 m are attributed to the Semicelatum Subzone (Tethyan nomenclature). At the base, there occurs a level with D. (Orthodactylites) crosbeyi (Simpson) associated with Lobothyris arcta (Dubar) which allows a good correlation with the Clevelandicum Subzone (or Horizon) of northwestern Europe. The topmost 5 m of the deposits are dated to the Levisoni Zone with Eleganticeras sp. The anoxic event at the beginning of this Zone is only indicated by an abnormal variability of the foraminifera. The presence of Lenticulina obonensis (Cubaynes) mg Planularia indicates stressing conditions.

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Latest Albian (Vraconian) brachiopod fauna from North Dobrogea (Romania) : taxonomy, palaeoecology and palaeobiogeography

Gradinaru E., Barbulescu A., Owen E.

Acta Geologica Polonica

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2006

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Vol. 56, no. 1

67-88

EN

The latest Albian (Vraconian) brachiopod fauna from Enisala, in North Dobrogea, includes representatives of rhynchonellids and terebratulids. The rhynchonellids are scarce, representing two families, Cyclothyrididae and Tetrarhynchiidae. The Cyclothyrididae with the subfamily Cyclothyridinae, and the Tetrarhynchiidae with the subfamily Cretirhynchiinae, are represented by rare specimens of ? Cyclothyris sp. and Burrirhynchia cf. sigma (SCHLOENBACH, 1867), respectively. The terebratulids are very abundant and include representatives of several families, as follows: Sellithyrididae, Capillithyrididae, Cancellothyrididae and Terebrataliidae. The Sellithyrididae, which make up the bulk of the assemblage, are represented by two subfamilies: Sellithyridinae with Sellithyris upwarnesis (WALKER, 1870), Boubeithyris boubei (D'ARCHIAC, 1847) and Ovatathyris cf. potternensis OWEN, 1988, and Nerthebrochinae with Harmatosia crassa (D'ARCHIAC, 1847).The Capillithyrididae are represented by the subfamily Capillithyridinae with Capillithyris capillata (D'ARCHIAC, 1847). The Cancellothyrididae are represented by the subfamily Cancellothyridinae with numerous specimens of Terebratulina protostriatula OWEN, 1988. The Terebrataliidae are represented by the subfamily Gemmarculinae with scarce specimens of Gemmarcula canaliculata (ROEMER, 1840) and Gemmarcula sp. The abundance and diversity of the terebratulids in the brachiopod assemblage from Enisala was related to favourable environmental conditions connected with the onset of the marine transgression on North Dobrogea during the latest Albian. There is a marked stratigraphic lag with some species which in North Dobrogea occur in the latest Albian appearing in the Early Cenomanian in Central and Western Europe. This suggests that North Dobrogea was located on the main route of the westward migration of the mid-Cretaceous brachiopod faunas.

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The Miocene brachiopods from the silty facies of the intra-Carpathian Nowy Sącz Basin (Poland)

Bitner M. A., Kaim A.

Geological Quarterly

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2004

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Vol. 48, No 2

193--198

EN

The micromorphic brachiopods have been found in the Miocene silty deposits of Kamienica Nawojowska in the intra-Carpathian Nowy Sącz Basin, southern Poland. The assemblage consists of two species Argyrotheca cuneata (Risso, 1826) and A. cordata (Risso, 1826). The presence of stenohaline brachiopods indicatesMiddleMiocene (?Badenian) age of the sediment. The preliminary sedimentological and palaeoecological analysis suggests that brachiopods and associated faunamight be transported basinward from a shallower setting.

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The Frasnian-Famennian boundary in the Southern Urals

Abramova A. N., Artyushkova O. V.

Geological Quarterly

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2004

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Vol. 48, No 3

217-323

EN

On the western slope of the Southern Urals, a continuous conodont zone sequence within different facies of the Frasnian-Famennian (F-F) boundary beds is documented. In all the sections the boundary between both stages runs within lithologically uniform successions and can be determined only by a sharp faunal change. In brachiopod facies, it is placed within brachiopod shell beds and relates to the base of the Barma Beds, i.e., the level marked by a simultaneous appearance of the index brachiopod species Pugnoides(?) markovskii and the zonal conodont species Palmatolepis triangularis. In goniatite facies, the F-F boundary can be traced by the disappearance of diverse Frasnian conodonts and goniatites of the genus Manticoceras, coupled with the first occurrence of the conodont Pa. triangularis; the sequence shows also the well-known icriodid blooms in the earliest Famennian. Finds of Famennian goniatites (representatives of the genus Cheiloceras) are confined to the crepida zones. In the sections of theWest-Zilair, where the F-F boundary passage consists of siliceous- terrigenous deposits, the boundary can be established only by a change in conodont assemblages. In all the sections under investigation the F-F boundary level shows a drastic faunal change that corresponds to the global Kellwasser Event.

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Siedlisko życia, miejsce pogrzebania oraz epibionty ramienionogów Sellithyris subsella (Leymerie, 1846) z muszlowców dolnego kimerydu Małogoszcza

Radwańska U., Radwański A.

Volumina Jurassica

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2003

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Vol. 1, no. 1

85-92