BSGF - Earth Sciences Bulletin最新文献

{"title":"Transfer zones in Mediterranean back-arc regions and tear faults","authors":"L. Jolivet, A. Menant, V. Roche, L. Le Pourhiet, A. Maillard, R. Augier, D. do Couto, C. Gorini, I. Thinon, Albane Canva","doi":"10.1051/BSGF/2021006","DOIUrl":"https://doi.org/10.1051/BSGF/2021006","url":null,"abstract":"Slab tearing induces localized deformations in the overriding plates of subduction zones and transfer zones accommodating differential retreat in back-arc regions. Because the space available for retreating slabs is limited in the Mediterranean realm, slab tearing during retreat has been a major ingredient of the evolution of this region since the end of the Eocene. The association of detailed seismic tomographic models and extensive field observations makes the Mediterranean an ideal natural laboratory to study these transfer zones. We review in this paper the various structures in back-arc regions differential retreat from the Alboran Sea to the Aegean-Anatolian region and discuss them with the help of 3D numerical models to better understand the partitioning of deformation between high-angle and low-angle faults, as well as the 3-D kinematics of deformation in the middle and lower crusts. Simple, archetypal, crustal-scale strike-slip faults are in fact rare in these contexts above slab tears. Transfer zones are in general instead wide deformation zones, from several tens to several hundred kilometers. A partitioning of deformation is observed between the upper and the lower crust with low-angle extensional shear zones at depth and complex association of transtensional basins at the surface. In the Western Mediterranean, between the Gulf of Lion and the Valencia basin, transtensional strike-slip faults are associated with syn-rift basins and lower crustal domes elongated in the direction of retreat (a-type domes), associated with massive magmatic intrusions in the lower crust and volcanism at the surface. On the northern side of the Alboran Sea, wide E-W trending strike-slip zones in the brittle field show partitioned thrusting and strike-slip faulting in the external zones of the Betics, and E-W trending metamorphic core complexes in the internal zones, parallel to the main retreat direction with a transition in time from ductile to brittle deformation. On the opposite, the southern margin of the Alboran Sea shows short en-échelon strike-slip faults. Deep structures are not known there. In the Aegean-Anatolian region, two main tear faults with different degrees of maturity are observed. Western Anatolia (Menderes Massif) and the Eastern Aegean Sea evolved above a major left-lateral tear in the Hellenic slab. In the crust, the differential retreat was accommodated mostly by low-angle shear zones with a constant direction of stretching and the formation of a-type high-temperature domes exhumed from the middle and lower crust. These low-angle shear zones evolve through time from ductile to brittle. On the opposite side of the Aegean region, the Corinth and Volos Rift as well as the Kephalonia fault offshore, accommodate the formation of a dextral tear fault. Here, only the brittle crust can be observed, but seismological data suggest low-angle shear zones at depth below the rifts. We discuss the rare occurrence of pure strike-slip faults in these","PeriodicalId":202681,"journal":{"name":"BSGF - Earth Sciences Bulletin","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128950570","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Thai amber: insights into early diatom history?","authors":"V. Girard, Simona Saint Martin, E. Buffetaut, J. Martin, D. Néraudeau, D. Peyrot, G. Roghi, E. Ragazzi, V. Suteethorn","doi":"10.1051/bsgf/2020028","DOIUrl":"https://doi.org/10.1051/bsgf/2020028","url":null,"abstract":"The origin of the diatoms still remains enigmatic. Their fossil record is scarce until the Late Cretaceous and great divergences exist between molecular data and the earliest fossil evidence. While molecular data indicate an origin during the Triassic or Early Jurassic, early fossil evidence is only from the Late Jurassic-Early Cretaceous. The discovery of diatoms in French mid-Cretaceous amber by the end of the 2000s already suggested a potential bias in the diatom fossil record as it made older many diatom lineages, the record of which hitherto began at the end of the Cretaceous. The Jurassic/Early Cretaceous fossil record of diatoms is extremely sparse and any new occurrence is important for retracing the evolutionary, palaeogeographical and palaeoenvironmental history of diatoms. Thai amber has yielded a new diatom specimen that has been attributed to the genus Hemiaulus. Fossil assemblages and sedimentological data indicate that Thai amber and its Hemiaulus specimen are Late Jurassic in age. This discovery represents the oldest hitherto known specimen of Hemiaulus and so extends the fossil record of the bipolar diatoms and of the genus Hemiaulus by several dozens of millions of years and brings closer the fossil evidence and molecular data (that estimated an origin of the bipolar diatoms about 150 Ma ago). It reinforces the hypothesis of a pre-Cretaceous fossil diatom records and also supports an origin of the diatoms in shallow coastal environments.","PeriodicalId":202681,"journal":{"name":"BSGF - Earth Sciences Bulletin","volume":"260 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116395173","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Les « ichtyolites » (Actinopterygii) de la collection Jean-Baptiste Beurard (1745–1835) : intérêt historique et redécouverte de la série type d’Armigatus brevissimus (Blainville, 1818) du Cénomanien du Liban","authors":"A. Brignon","doi":"10.1051/bsgf/2021025","DOIUrl":"https://doi.org/10.1051/bsgf/2021025","url":null,"abstract":"Cet article souligne le rôle Jean-Baptiste Beurard dans l’histoire de la paléoichtyologie. Ancien chanoine de la cathédrale de Toul, il trouva après les affres des débuts de la Révolution un emploi d’agent du gouvernement attaché à l’administration des mines entre 1794 et 1815. Chargé de la surveillance des mines de mercure dans les nouveaux départements annexés par la France sur la rive gauche du Rhin, il redécouvrit en juillet 1799 le fameux gisement d’« ichtyolites » (poissons fossiles) imprégnés de cinabre de Münsterappel daté du Permien inférieur. Il envoya plusieurs spécimens dans des collections institutionnelles parisiennes. Des représentants de l’espèce Paramblypterus duvernoy (Agassiz, 1833) (Actinopterygii, Amblypteridae), probablement envoyés par Beurard avant 1809 d’après le témoignage de Barthélémy Faujas de Saint-Fond, ont été identifiés dans les collections du Muséum national d’Histoire Naturelle, Paris. Un autre spécimen ayant appartenu de manière incontestable à Beurard est conservé dans les collections Géosciences de Sorbonne Université et revêt un intérêt historique tout particulier. Beurard possédait également dans sa collection deux échantillons de poissons fossiles du Cénomanien de Haqel dans l’actuel Liban, qu’il avait reçu de son neveu Claude Charles Harmand (1784–1847), officier de marine, en 1817. À partir d’eux, Henri Marie Ducrotay de Blainville décrivit deux espèces qu’il nomma Clupea beurardi Blainville, 1818a et Clupea brevissima Blainville, 1818a. La première n’est plus considérée comme valide et la seconde est aujourd’hui assignée au genre Armigatus Grande, 1982 (Actinopterygii, Clupeomorpha) dont elle est l’espèce type. Un de ces spécimens est conservé au Natural History Museum, Londres, et provient de la collection de William Willoughby Cole (1807–1886), comte d’Enniskillen, qui avait acquis une partie de la collection Beurard. Étiqueté par erreur Clupea beurardi par Beurard, cet échantillon porte en réalité les quatre syntypes d’Armigatus brevissimus. Un lectotype est désigné ici pour fixer le statut de cette espèce, certainement la plus abondante et la plus iconique du gisement de Haqel.","PeriodicalId":202681,"journal":{"name":"BSGF - Earth Sciences Bulletin","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128184701","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Digging into the ancestral stocks of Jurassic lineages: ostracods (Crustacea) from Carnian (Late Triassic) sponge mounds from the Maantang Formation (South China)","authors":"M. Forel, B. Thuy, M. Wisshak","doi":"10.1051/bsgf/2019009","DOIUrl":"https://doi.org/10.1051/bsgf/2019009","url":null,"abstract":"Microbial-sponge reef mounds of the Carnian, Late Triassic, Maantang Formation crop out along the northwestern margin of the Sichuan Basin in South China. Samples from three mounds have been investigated and their ostracod assemblages are here described for the first time. Thirty-three species are present, distributed into 19 genera, including five newly described species:Carinobairdiacabralaen. sp.,Hiatobairdia senegasin. sp.,Hiatobairdiazhengshuyingin. sp.,Hungarella gommeriin. sp,Pontocyprella goussardin. sp. While most of the encountered genera are already known from the Carnian stage worldwide, the Maantang assemblages are precursors in providing the oldest occurrences of the family Schulerideidae, typical of the Middle and Late Jurassic of Europe, and of the genusCarinobairdia, which was until now restricted to the Norian-Rhaetian interval. These records demonstrate the underestimated importance of the easternmost Tethys in the early Mesozoic evolution of marine ostracods. Some important Jurassic European taxa might have originated on the eastern margin of the Tethys during the Carnian, migrated to the western Tethys later during the Late Triassic and diversified there up to the record known for the European Jurassic. Microbioerosion trace fossil analysis of associated brachiopod shells revealedOrthogonum giganteumas the sole identifiable ichnotaxon and represents the first record of this ichnospecies in Triassic strata. The complete absence of microborings produced by phototrophic trace makers points towards aphotic depths for the deposition of the Maantang Formation, providing independent evidence suggesting that typical shallow water ostracods (Carinobairdia, Schulerideidae) radiated in relatively deep settings.","PeriodicalId":202681,"journal":{"name":"BSGF - Earth Sciences Bulletin","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128231564","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Amber, from deposit to inclusions: new data","authors":"J. Martin, Simona Saint Martin","doi":"10.1051/BSGF/2021001","DOIUrl":"https://doi.org/10.1051/BSGF/2021001","url":null,"abstract":"We wish to dedicate this special issue devoted to amber to the memory of our recently deceased colleague Gérard Breton. Associate professor in Natural Sciences, doctor of state “ès-science”, Gérard Breton first taught in secondary schools and then served for 32 years as director of the Museum of Natural History of Le Havre (1973–2005). As a true naturalist animated by a constant scientific curiosity, Gérard Breton, tackled many study themes in the field of paleontology. More particularly, its contribution to the knowledge of micro-inclusions of amber for over the past twenty years has been constant and rich in information and concepts. Following a few authors who have described and figured microorganisms contained in amber (e.g. Poinar, 1977, 1992; 1994; Waggoner, 1993, 1994; Poinar et al., 1993a, 1993b; Dörfelt and Schäfer, 1998; Schönborn et al., 1999), he was the first to tackle the difficult exercise of identifying these micro-inclusions in French ambers. In a first work, he thus mentioned the microflora contained in amber of Sparnacian age in the South of France (Breton et al., 1999). Aware of the difficulty of directly assimilating micro-inclusions to current microorganisms determined today on genomic bases, he developed a comparative taxonomy essentially based on morphology (Breton, 2010). He is the author of numerous new taxa of actinomycetes, bacteria, cyanobacteria and filamentous fungi (Breton and Tostain, 2005; Breton, 2010, 2012; Breton et al., 2013, 2014). From a taphonomic point of view, he first favored the trapping process, especially on the surface of resin flows, to explain the presence of real microbial mats (Breton and Tostain, 2005; Breton, 2007), then he integrated subsequently the colonization process by networks of centripetal growth microorganisms in the resin (Breton, 2010, 2011, 2012, Breton et al., 2013, 2014, 2018). Consequently, he considered the resin as a real culture medium (Breton, 2011). Thanks to his knowledge of amber microorganisms, he has also been able to provide his expertise and collaborate in numerous works (Girard et al., 2008, 2009a, 2009b; 2011; 2013; Adl et al., 2011; Néraudeau et al., 2020).","PeriodicalId":202681,"journal":{"name":"BSGF - Earth Sciences Bulletin","volume":"48 6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130008900","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Le gisement à étain–cuivre–indium de Charrier (Allier) : un skarnoïde viséen (340 Ma) traceur de la métallogenèse varisque du nord Massif central","authors":"É. Marcoux, Marc Poujol, Pierre Wadier","doi":"10.1051/bsgf/2022019","DOIUrl":"https://doi.org/10.1051/bsgf/2022019","url":null,"abstract":"Charrier est un petit gisement de cuivre–étain riche en indium de type skarnoïde du Forez (nord du Massif central). Il est encaissé dans une série volcanosédimentaire du Dévono-dinantien au contact du granite viséen des Bois-noirs. Sa genèse comprend une étape précoce oxydée de haute température (vers 550–350 °C) à cassitérite–magnétite, suivie d’une étape réduite sulfurée (vers 350–250 °C) à bornite–chalcopyrite dominantes avec wittichénite, tennantite, sphalérite, bismuthinite et roquesite (CuInS2) qui se déroule en conditions de pH acide et de faible fugacité en soufre. L’apatite hydrothermale fournit un âge U–Pb de 340,7 ± 2,6 Ma identique à celui du granite (341 ± 4 Ma) ; il est confirmé par l’âge U–Pb de 332 ± 12 Ma obtenu sur cassitérite. Le gisement s’est donc formé au début de l’extension tardi-varisque par l’action des fluides magmatiques à Sn–Bi–In issus du granite des Bois-noirs (341 ± 4 Ma) ayant interagi avec la série volcanosédimentaire. Charrier pourrait traduire la superposition d’un district à cuivre sur une vaste ceinture à étain (et tungstène), ce qui suggère la présence d’autres gisements de cuivre/étain dans cette région. Cette superposition est bonifiée par une richesse particulière en indium du nord-Forez, ce métal s’exprimant du Viséen (roquesite de Charrier) jusqu’au Lias (sphalérite à indium des filons plombo–zincifères), illustration du phénomène de permanence métallique.","PeriodicalId":202681,"journal":{"name":"BSGF - Earth Sciences Bulletin","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125557359","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Detailed tectonic reconstructions of the Western Mediterranean region for the last 35 Ma, insights on driving mechanisms","authors":"A. Romagny, L. Jolivet, A. Menant, E. Bessière, A. Maillard, Albane Canva, C. Gorini, R. Augier","doi":"10.1051/bsgf/2020040","DOIUrl":"https://doi.org/10.1051/bsgf/2020040","url":null,"abstract":"Slab retreat, slab tearing and interactions of slabs are first-order drivers of the deformation of the overriding lithosphere. An independent description of the tectonic evolution of the back-arc and peripheral regions is a pre-requisite to test the proposed conceptual, analogue and numerical models of these complex dynamics in 3-D. We propose here a new series of detailed kinematics and tectonic reconstructions from 35 Ma to the Present shedding light on the driving mechanisms of back-arc rifting in the Mediterranean where several back-arc basins all started to form in the Oligocene. The step-by-step backward reconstructions lead to an initial situation 35 Ma ago with two subduction zones with opposite direction, below the AlKaPeCa block (i.e.belonging to the Alboran, Kabylies, Peloritani, Calabrian internal zones). Extension directions are quite variable and extension rates in these basins are high compared to the Africa-Eurasia convergence velocity. The highest rates are found in the Western Mediterranean, the Liguro-Provençal, Alboran and Tyrrhenian basins. These reconstructions are based on shortening rates in the peripheral mountain belts, extension rates in the basins, paleomagnetic rotations, pressure-temperature-time paths of metamorphic complexes within the internal zones of orogens, and kinematics of the large bounding plates. Results allow visualizing the interactions between the Alps, Apennines, Pyrenean-Cantabrian belt, Betic Cordillera and Rif, as well as back-arc basins. These back-arc basins formed at the emplacement of mountain belts with superimposed volcanic arcs, thus with thick, hot and weak crusts explaining the formation of metamorphic core complexes and the exhumation of large portions of lower crustal domains during rifting. They emphasize the role of transfer faults zones accommodating differential rates of retreat above slab tears and their relations with magmatism. Several transfer zones are identified, separating four different kinematic domains, the largest one being the Catalan-Balearic-Sicily Transfer Zone. Their integration in the wider Mediterranean realm and a comparison of motion paths calculated in several kinematic frameworks with mantle fabric shows that fast slab retreat was the main driver of back-arc extension in this region and that large-scale convection was a subsidiary driver for the pre-8 Ma period, though it became dominant afterward. Slab retreat and back-arc extension was mostly NW-SE until ∼ 20 Ma and the docking of the AlKaPeCa continental blocks along the northern margin of Africa induced a slab detachment that propagated eastward and westward, thus inducing a change in the direction of extension from NW-SE to E-W. Fast slab retreat between 32 and 8 Ma and induced asthenospheric flow have prevented the transmission of the horizontal compression due to Africa-Eurasia convergence from Africa to Eurasia and favored instead upper-plate extension driven by slab retreat. Once slab retreat had slowed","PeriodicalId":202681,"journal":{"name":"BSGF - Earth Sciences Bulletin","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133882991","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Albian bivalves from Madiela Formation in north Gabonese coastal basin","authors":"Benjamin Musavu Moussavou","doi":"10.1051/BSGF/2019006","DOIUrl":"https://doi.org/10.1051/BSGF/2019006","url":null,"abstract":"A study of Albian bivalves from Madiela Formation in north of Gabonese coastal basin has been carried out from N’Toum quarry geological section. Four genera including six species are identified: Liopistha (Psilomya) sp. 1, ? Liopistha (Psilomya) sp. 2, Megaporomya sp., Neithea (Neithea) dutrugei (Coquand, 1862), Pleuromya sp. 1 and Pleuromya sp. 2. One morphotype is identified as Bivalvia gen. et sp. indet. The genus Megaporomya Ayoub-Hannaa et al., 2013 and all identified species, except Neithea (Neithea) dutrugei (Coquand, 1862), are found for the first time in Gabonese coastal basin. Now, a total of twelve species of bivalves have been reported from the Madiela Formation. In Gabon, the presence for the first time of genera Liopistha and Pleuromya in N’Toum quarry geological section which is assigned to the Albian permits us to expand their geographical distribution until N’Toum region, and their age range to Albian.","PeriodicalId":202681,"journal":{"name":"BSGF - Earth Sciences Bulletin","volume":"100 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114608015","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Tectono-metamorphic evolution of shallow crustal levels within active volcanic arcs. Insights from the exhumed Basal Complex of Basse-Terre (Guadeloupe, French West Indies)","authors":"Alexiane Favier, J. Lardeaux, L. Legendre, C. Vérati, M. Philippon, M. Corsini, P. Münch, S. Ventalon","doi":"10.1051/bsgf/2019011","DOIUrl":"https://doi.org/10.1051/bsgf/2019011","url":null,"abstract":"In order to decipher the tectono-metamorphic evolution of shallow crustal levels of the active volcanic arc of the Guadeloupe archipelago (Lesser Antilles) we present new geochemical, geochronological, mineralogical and structural investigations of the so-called Basal Complex, the oldest and most eroded volcanic complex of Basse-Terre in Guadeloupe. Based on geochemical and mineralogical criteria we propose an updated geological map of this northern area of Basse-Terre. Using 40Ar–39Ar geochronology we demonstrate first that the eroded “Gros Morne” of Deshaies belong to the Basal Complex, and second that this complex is characterized by 4.3 to 2 Ma old volcanism. Structural analysis reveals a long-lived deformation history with the development through time of N80-N100 schistose zones; N110-N140 and N160-N10 oriented hydrothermal breccias and N140-N150 brittle normal faults. The boundary between the Basal Complex and the southernmost Septentrional Chain corresponds to a series of faults with N 150° and N 50° main directions. Detailed mineralogical and petrological investigations, including thermodynamic modeling, allow the identification of three phases of post-magmatic mineralogical transformations with first a high-temperature stage under Greenschist to sub-Greenschist facies conditions (0.6–2 kbar for 250–300 °C), a re-equilibration under Zeolite facies conditions and finally a sub-surface alteration. The consistency between P–T conditions of metamorphism and the present day measured geothermal gradient demonstrates that the metamorphic pattern is the record of hydrothermal fluids circulation during building and cooling of the Lesser Antilles magmatic arc. The tectono-metamorphic evolution recognized in the Basal Complex enables us to propose a conceptual model for heat and fluid transport within shallow crustal levels of the Guadeloupe active volcanic arc.","PeriodicalId":202681,"journal":{"name":"BSGF - Earth Sciences Bulletin","volume":"146 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116283522","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Towards objectivity in Ostracoda species definition","authors":"A. Lord","doi":"10.1051/bsgf/2020029","DOIUrl":"https://doi.org/10.1051/bsgf/2020029","url":null,"abstract":"The problem of consistent identification of unornamented fossil ostracod taxa, especially species, is reviewed in an historical context. The solution lies in modern imaging and image storage and handling technologies combined with a careful but pragmatic (heuristic) approach to identification and taxonomy.","PeriodicalId":202681,"journal":{"name":"BSGF - Earth Sciences Bulletin","volume":"156 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121878756","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}