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Orthophragminid and operculinid events at the Middle-Upper Eocene boundary in Europe.
No full textIn some Middle Lutetian (Gibret, Nousse and Angoumé, France), Upper Lutetian (Ajka and Padragkút in Hungary) and Lower Bartonian (Dudar in Hungary, San Pancrazio in Italy and Biarritz, Rocher de Peyreblanque in France) localities (see Less, 1998) the richest orthophragminid assemblages ever seen can be found. The members of nineteen evolutionary lineages are represented in them. By comparing the orthophragminid content of the Middle and Upper Priabonian localities (Priabona, Sorgente, Valle Granella and the Middle-Upper Priabonian of Mossano in Italy and Kisgyör, Remete-kút in Hungary) with them, we find that eleven of the nineteen lineages had been lost and only five new (and rare) species appeared. The eight lineages that are coming from the Middle Eocene and surviving until the end of the Eocene are: Discocyclina dispansa, D. augustae, D. radians, D. trabayensis, Orbitoclypeus varians, O. furcatus, Asterocyclina stellata and A. stella.The orthophragminid events in the Late Bartonian and Early Priabonian can be followed in correlating them with three other successive larger foraminiferal events, such as (from top to bottom):- Event 3: The appearance of Spiroclypeus that has never been found in the Middle Eocene and with large Nummulites.- Event 2: The extinction of large Nummulites that have never been found with Spiroclypeus. Their supposed occurrence (especially of N. ex gr. millecaput) in the Upper Eocene of Slovakia and Armenia has to be carefully studied. Papazzoni & Sirotti (1995) recognized a considerable gap between Events 2 and 3 in N Italy whose duration however, has to be analysed in other regions, too. Papazzoni (this volume) stressed the possible bias of local paleoecological conditions on the biostratigraphical distribution of some species.- Event 1: The appearance of involute Heterostegina (former Grzybowskia) that can be found with the last large Nummulites in some sections of N Italy (Papazzoni & Sirotti, 1993 and 1995), Poland (Bieda, 1963), Armenia (Nemkov, 1967) and Urhida in Hungary (our new data).Recently Event 3 seems to be the most adequate for placing the lower boundary of the Priabonian as it has been found by Papazzoni & Sirotti (1995) because it appears exactly at the base of the Priabonian in the Mossano section. At the same time, the rapid nepionic acceleration of Heterostegina reticulata manifested in the strong reduction of non-subdivided, operculinid chambers (parameter X shows their number in the spire of the A-forms, including the proloculus) can be considered the most reliable evolutionary clock in order to calibrate the events listed above. By using the Papazzoni & Sirotti (1993) data from the Mossano section and our new data from Urhida and Noszvaj, Hungary the evolution of parameter X can be sketched as follows:- X (mean) reduces from at least 15-16 to 7-9 between Events 1 and 2 (sample Mossano 2 of Papazzoni & Sirotti, 1993 and two new samples from Urhida, Hungary).- No statistical data from between Events 2 and 3.- X (mean) is about 5 just after Event 3 (sample Mossano 10 of Papazzoni & Sirotti, 1993).- It reduces until 3 in the following part of the Priabonian (sample Mossano 16 in Papazzoni & Sirotti, 1993 and a new sample from Noszvaj, Hungary).The lineage of Assilina schwageri-alpina also shows a rather rapid increase of the proloculus of the A-forms in the Bartonian-Priabonian interval as indicated by Papazzoni (1998) and confirmed by our data from Urhida, Noszvaj and Kisgyör, Remete-kút (Less, 1999), too. According to these, the inner cross diameter of the proloculus of A-forms is about 125-135 μm at the Middle-Upper Eocene boundary (Event 3). At the same time, it is difficult to follow the development of the Operculina roselli-gomezi lineage in the context of the events listed above, mostly because the boundary of the two successive species is not clearly defined. However, this lineage is very frequent in some samples listed below after Event 1, so it needs further studies.For characterizing the orthophragminid events around the Middle-Upper Eocene boundary several samples have been used: The Middle-Upper Lutetian (O.9-11 orthophragminid zones) and Lower Bartonian (O.12-13) ones listed at the beginning of this paper were formed before Event 1, while the Middle-Upper Priabonian (O.15-16) ones well after Event 3. The other samples (their orthophragminid fauna was seen and evaluated by the author: all they indicate the O.14 zone with a few exceptions shown in brackets) are:- Between Events 1 and 2: Gurb (O.13) in Spain (Papazzoni & Sirotti, 1995 using also Hottinger, 1977, fig. 38 and C. Ferrández's unpublished data), Siest in France (Less, 1998), samples from Mossano, Italy: MOSS 1 and 11 in Papazzoni & Sirotti (1995) (MOSS. 001 and 2 in Papazzoni & Sirotti, 1993), Mossano 31 (~MOSS 11) (Schweighauser, 1953, see also in Less, 1998), new samples from Hungary (see them in the Field-trip guide-book of IGCP 393 for 2000): Bajót, Domonkos Creek section, "millecaput" beds, Urhida "millecaput" beds.- Between Events 2 and 3: Samples Igualada 4-5 in Spain (Papazzoni & Sirotti, 1995, using also C. Ferrández's unpublished data) and MOSS 16 (former MOSS. 7) of Mossano, Italy (Papazzoni & Sirotti, 1995).- After Event 2 but in uncertain relationship with Event 3: New samples from Bajót, Hungary, "Discocyclina + Operculina" beds: Domonkos Creek section and the quarry W of the village (O.15).- Just after Event 3: Samples in Mossano, Italy: MOSS 20 (former MOSS. 10) in Papazzoni & Sirotti (1995), Mossano 44 (O.14/15) and 50 (O.15) (Schweighauser, 1953, see also in Less, 1998 as well as sample MOSSA), a new sample from Hungary: Urhida, "Discocyclina" beds.Therefore, two main orthophragminid extinction events could be distinguished at the Middle-Upper Eocene boundary, the first (Event α) occurring before or simultaneously with Event 1, while the second (Event β) after Event 3.- Event α: Five of the eleven lost lineages cannot be found after Event 1. These are: Discocyclina pulcra, D. spliti, Nemkovella katoae, Orbitoclypeus douvillei, and O. schopeni (the latter is extremely rare already in the Middle-Upper Lutetian and Lower Bartonian). These lineages became extinct very likely well before the end of the Bartonian, in the SBZ 17 zone of Serra-Kiel et al. (1998) (or in the case of D. spliti maybe even in SBZ 16). This event roughly coincides with the extinction of some nummulitid lineages such as Assilina exponens and probably also Nummulites brongniarti and N. puschi.- Event β: Four of the six lineages having survived the first orthophragminid extinction event, Nemkovella strophiolata, Asterocyclina alticostata, A. kecskemetii and Discocyclina pratti can still be found with the first Spiroclypeus (the first two in Mossano, the last three in Urhida), thus they surely survived Event 3. The fifth lineage, D. discus also survived at least Event 2 as it can be found in the Bajót, Domonkos Creek section. Since Event 3 could not be detected so far in this region, this extinction is joined with that of the previous four lineages. Finally, the sixth lineage, Orbitoclypeus daguini (with last occurrence in Gurb) is so rare (altogether 10 specimens from 6 localities are known) that its extinction can be tentatively placed together with that of the other five lineages.As it is mentioned earlier, five new orthophragminid species appeared in the Priabonian. They are so rare that here only their first occurrences are listed without any further conclusions: Discocyclina nandori in sample MOSSA (O.14 zone), between Events 3 and 4; D. euaensis in the quarry W of Bajót (O.15), between Events 2 an 4; D. samantai (the ribbed variant of D. pratti minor, the last member of that lineage) in the "Discocyclina" beds of Priabona (O.14), after Event 3 and in the Lábatlan, Raibl-patak quarry (Less, 1987) (O.15), before Event 4; D. ruppi (see Rasser et al., 2000) in the "Discocyclina + Operculina" beds of the Bajót, Domonkos Creek section (O.14), after Event 2; Asterocyclina priabonensis in sample Mossano 44 (O.14/15), between Events 3 and 4.As it is clear from the list of orthophragminid samples representing the Bartonian-Priabonian transition, Event 1 can very probably be placed into the uppermost part of O.13 zone, Events 2 and 3 into the O.14 zone while Event 4 into the lower part of O.15 zone, thus almost the whole interval between Events 1 and 4 belongs to the O.14 zone within which the development of orthophragminid lineages is hardly detectable. By using our new data from Urhida and Bajót, Domonkos Creek, the only change is that Discocyclina pratti pratti is succeeded by D. pratti minor (their limit based on the population mean of the outer cross diameter of the deuteroconch is 700 μm) that could happen between Events 1 and 2.This research is a contribution to IGCP 393 and was supported by the National Scientific Fund of Hungary (OTKA, grants 23880, 32370), and by the Italian MURST 60% fund (responsible Prof. A. Sirotti, Italy)
The middle to late Eocene evolution of nummulitid foraminifer Heterostegina in the Western Tethys
Full text linkMegalospheric forms of Western Tethyan late Bartonian to late Priabonian involute Heterostegina from numerous localities, marking different ecological conditions, were morphometrically investigated. They belong to three species, H. armenica, H. reticulata, and H. gracilis based on the presence/absence of granulation, on the chamberlet characteristics and on the relative size of proloculus. Within these species a very rapid evolution could be observed in the reduction of the number of operculinid chambers, in the increase of the number of chamberlets and partially in the increase of the proloculus size. This evolution is demonstrated by stratigraphic superpositions in several localities (especially in the Mossano section), and is supported also by the change of co−occurring fossils, starting with the disappearance of large−sized Nummulites, then followed by the appearance of the genus Spiroclypeus and then by the disappearance of orthophragmines of middle Eocene acme. Based on the reduction of operculinid chambers, two chronosubspecies of Heterostegina armenica and seven of H. reticulata are defined biometrically (four of them: H. armenica tigrisensis, H. reticulata tronensis, H. r. hungarica, and H. r. mossanensis are introduced here). This allows to subdivide the Shallow Benthic Zone (SBZ) 18 into three and SBZ 19 into two subzones. The extremely rapid evolution of H. reticulata allows to calibrate larger foraminiferal events around the middle/late Eocene boundary. The extinction of large−sized Nummulites seems to be heterochronous in the late Bartonian in having migrated eastward, while the first appearance of Spiroclypeus is shown to be synchronous at the base of the Priabonian. The middle/upper Eocene (=Bartonian/Priabonian) boundary is to be placed at the base of the Priabona marls in the Mossano section corresponding to the SBZ 18/19 limit, to the first appearance of genus Spiroclypeus, to that of Nummulites fabianii and of Heterostegina reticulata mossanensis. It falls into the upper part of both the P15 and NP18 planktic zones. The Western Tethyan Eocene involute Heterostegina became extinct, apparently with no Oligocene successors
Basement Types, Lower Eocene Series, Upper Eocene Olistostromes and the Initiation of the Southern Thrace Basin, NW Turkey
No full textThe Eocene sequence of the southern Thrace Basin unconformably overlies two types of basement: (1) Slate, limestone and phyllite crop out in small inliers under the Upper Eocene conglomerates and limestones in the Mecidiye region, north of Saros Bay. These low-grade metamorphic rocks form the eastern extension of the Circum-Rhodope Belt of Greece. (2) In the Şarköy region south of the Ganos Fault, tectonically elevated basement consisting of serpentinite, metadiabase and Upper Cretaceous blueschists is unconformably overlain by the upper Bartonian to lower Priabonian shallow marine limestones of the Soğucak Formation. In some places erosional remnants of an upper Ypresian transgressive sequence (the newly discovered Dişbudak series) underlie the Soğucak Limestones. This Dişbudak series starts with sandstone and conglomerate and passes up into sandy limestone, marl and shale.
Hydrocarbon exploration wells south of the Ganos Fault have also encountered an ophiolitic mélange basement under the Dişbudak series and/or under the Soğucak Formation. The Ganos Fault forms the boundary between the two basement types.
The Soğucak Limestone is overlain by an Upper Eocene to Early Oligocene flysch sequence with olistostromes. The clasts in the flysch include the Soğucak Limestone, Cretaceous and Palaeocene pelagic limestone, serpentinite, basalt,gabbro, greywacke, quartz-diorite and greenschist. They range in size from sand grains to olistoliths up to one kilometer across. Composite olistoliths consist of pelagic limestone or basalt overlain by the Upper Eocene limestone. The Upper Eocene mass flows were probably formed in an extensional setting and were derived from the south from the flanks of large normal faults related to the opening of the southern Thrace Basin.
The Dişbudak series is absent along the observed basement-Eocene contacts, which implies that the main transgression leading to the development of the southern Thrace Basin started in the late Bartonia
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Evolution of western Tethyan involute Heterostegina from late Bartonian to the end-Priabonian
Full text linkEocene involute Heterostegina having originated from the Operculina bericensis-roselli-gomezi group are widespread in the upper Bartonian and Priabonian beds of the Western Tethys. They have been morphometrically investigated and the important features of the equatorial section of their A-forms were statistically evaluated from thirty-four localities (including five topotypical ones). These localities represent the whole late Bartonian to latest Priabonian interval, mark different ecological conditions and extend from Spain to Armenia. Populations are ranked into three species, H. armenica, H. reticulata and H. gracilis based on the presence/absence of granulation, on the arrangement, shape and density of secondary chamberlets and on the relative size of the proloculus. These species form evolutionary lineages within which (especially within H. reticulata) a very rapid evolution could be observed with the reduction of the number of operculinid chambers, the increase of the number of secondary chamberlets (counted at chamber 14) and in the increase of the size of the proloculus, although the last turned out also to be ecologically controlled. This evolution is proven by the stratigraphical succession of populations in the Mossano section (Italy) and also by superpositions from other localities. The evolutionary changes are also accompanied by the change of co-occurring fossils starting with the disappearance of large-sized Nummulites, then followed by the appearance of genus Spiroclypeus and then by the disappearance of survivor middle Eocene orthophragmines. Based on the reduction of operculinid chambers as the most reliable parameter, two chronosubspecies of Heterostegina armenica (one of them is newly erected) and seven ones of H. reticulata (with three new subspecies) are defined biometrically. This allows us to subdivide the shallow benthic zone (SBZ) 18 very cautiously into three while SBZ 19 into two subzones. Heterostegina gracilis (the only species with granulation) characterizes the SBZ 20 zone. The middle/upper Eocene (=Bartonian/Priabonian) boundary is suggested to be placed onto the base of the “Priabona marls” in the Mossano section corresponding to the SBZ 18/19 limit, to the first appearance of genus Spiroclypeus, to that of Nummulites fabianii and Heterostegina reticulata mossanensis. It falls into the upper part of both the P 15 planktic foraminiferal and NP 18 calcareous nannoplankton zones. The extremely rapid evolution of H. reticulata accompanied with relatively large geographic distribution and wide ecological niche allows calibrating larger foraminiferal events around the proposed Bartonian/Priabonian boundary. As a working hypothesis, the extinction of large-sized Nummulites seems to be heterochronous in the late Bartonian in having migrated eastward. Relying on data from Italy, Hungary and Turkey, the first appearance of Spiroclypeus (with the same evolutionary degree) is proven to be synchronous in the very base of the Priabonian. Mediterranean Eocene involute Heterostegina became extinct very probably with no descendants at the very end of the Eocene. This research was realized in the frame of I.G.C.P. project 393 having financed also some of Less’s travels. The final phase of the work was sponsored for Less by the National Scientific Fund of Hungary (OTKA, Grants no T 037619, 042799 and 060645), for Özcan by TÜBITAK (project no YDABAG–101Y060), for Papazzoni by MIUR Cofin 2002–2005 (resp. prof. A. Russo, Modena) and for Stockar by the Cantonal Museum of Natural History (Lugano)
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Biostratigraphy and palaeoecology at the Middle-Upper Eocene boundary: the Venetian area
No full textGeneral geological and paleontological description of the Colli Berici area. Some localities are described as stops of the field-trip organized for the 5th meeting of the IUGS-UNESCO-IGCP 393
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