On the basis of a fragmentary carapace a new extinct paguroid, Annuntidiogenes massetispinosus n. sp., is described from the upper Meerssen Member (Maastricht Formation, upper Maastrichtian) of the Maastrichtian type area in the southeast Netherlands. The new taxon represents the fifth and stratigraphically youngest member of this Mesozoic genus that shows a remarkably close resemblance to the extant diogenids Aeropaguristes (Rahayu DL, McLaughlin PA. 2010. Areopaguristes , a generic replacement name for Stratiotes Thomson, 1899 (Crustacea: Decapoda: Paguroidea: Diogenidae). Zootaxa 2509: 67–68), Paguristes (Dana JD. 1851. Conspectus crustaceorum quae in orbis terrarum circumnavigatione, Carolo Wilkes e classe reipublicae foederatae duce, lexit et descripsit. (Preprint from) Proceedings of the Academy of Natural Sciences , Philadelphia 5: 267–272) and Pseudopaguristes (McLaughlin PA. 2002. Pseudopaguristes , a new and aberrant genus of hermit crabs (Anomura: Paguridea: Diogenidae). Micronesica 34(2): 185–199). Morphological features of paguroid carapaces, not previously used by neontologists, form the basis for a further systematic refinement of the Paguroidea, with the erection of a new family, the Calcinidae n. fam.
{"title":"A new paguroid from the type Maastrichtian (upper Cretaceous, the Netherlands) and erection of a new family","authors":"René H. B. Fraaije, B. Bakel, J. Jagt","doi":"10.1051/BSGF/2017185","DOIUrl":"https://doi.org/10.1051/BSGF/2017185","url":null,"abstract":"On the basis of a fragmentary carapace a new extinct paguroid, Annuntidiogenes massetispinosus n. sp., is described from the upper Meerssen Member (Maastricht Formation, upper Maastrichtian) of the Maastrichtian type area in the southeast Netherlands. The new taxon represents the fifth and stratigraphically youngest member of this Mesozoic genus that shows a remarkably close resemblance to the extant diogenids Aeropaguristes (Rahayu DL, McLaughlin PA. 2010. Areopaguristes , a generic replacement name for Stratiotes Thomson, 1899 (Crustacea: Decapoda: Paguroidea: Diogenidae). Zootaxa 2509: 67–68), Paguristes (Dana JD. 1851. Conspectus crustaceorum quae in orbis terrarum circumnavigatione, Carolo Wilkes e classe reipublicae foederatae duce, lexit et descripsit. (Preprint from) Proceedings of the Academy of Natural Sciences , Philadelphia 5: 267–272) and Pseudopaguristes (McLaughlin PA. 2002. Pseudopaguristes , a new and aberrant genus of hermit crabs (Anomura: Paguridea: Diogenidae). Micronesica 34(2): 185–199). Morphological features of paguroid carapaces, not previously used by neontologists, form the basis for a further systematic refinement of the Paguroidea, with the erection of a new family, the Calcinidae n. fam.","PeriodicalId":55978,"journal":{"name":"Bulletin de la Societe Geologique de France","volume":"20 1","pages":"17"},"PeriodicalIF":0.0,"publicationDate":"2017-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90312156","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2016-12-01DOI: 10.2113/GSSGFBULL.187.6.245
C. Lécuyer
Residence times of several dissolved chemical elements in seawater are revisited on the basis of updated river and groundwater chemical fluxes. A classification of the considered elements of geochemical interest (B, C, N, Na, Mg, Si, P, S, Cl, Ca, K, Li and Sr) is proposed accordingly to the solubility products of their main host minerals as well as their biological reactivity in the seawater column. The origin of seawater salinity is also discussed through both processes of early mantle degassing and continental growth. Finally, changes in seawater chemistry as well as in the total concentration of dissolved elements are investigated in the light of geological and biological processes such as continental erosion, hydrothermal activity, closure and opening of marine basins, climate forcing, marine productivity, and the Devonian rising of vascular plants. Taking into account groundwater fluxes and chemistry, and a revised lower mass of the oceans, residence times of chemical elements in the ocean have been calculated lower than commonly accepted in the literature for several decades. Both changes in salinity and chemistry of seawater took place throughout the Earth’s history at the m.y. timescale. Continents did not emerge before 3 Gy ago, thus excluding the weathering of their surfaces and the transport of alkali and calc-alkali elements by the rivers to the oceans. The only available sources, albeit to a limited extent, were possibly volcanic islands. As sodium is the main cation responsible for seawater salinity, calcium could have contributed to the charge balance of seawater to preclude the development of highly acidic waters. Indeed, the high-temperature hydrothermal alteration of oceanic crust is an important source of calcium that could have accumulated in seawater in the absence of its removal by calcifying organisms. It means that the earliest oceans could have been ‘CaCl2 dominated oceans’ instead of the ‘NaCl dominated oceans’ that prevailed during the Proterozoic and Phanerozoic.
{"title":"Seawater residence times of some elements of geochemical interest and the salinity of the oceans","authors":"C. Lécuyer","doi":"10.2113/GSSGFBULL.187.6.245","DOIUrl":"https://doi.org/10.2113/GSSGFBULL.187.6.245","url":null,"abstract":"Residence times of several dissolved chemical elements in seawater are revisited on the basis of updated river and groundwater chemical fluxes. A classification of the considered elements of geochemical interest (B, C, N, Na, Mg, Si, P, S, Cl, Ca, K, Li and Sr) is proposed accordingly to the solubility products of their main host minerals as well as their biological reactivity in the seawater column. The origin of seawater salinity is also discussed through both processes of early mantle degassing and continental growth. Finally, changes in seawater chemistry as well as in the total concentration of dissolved elements are investigated in the light of geological and biological processes such as continental erosion, hydrothermal activity, closure and opening of marine basins, climate forcing, marine productivity, and the Devonian rising of vascular plants. Taking into account groundwater fluxes and chemistry, and a revised lower mass of the oceans, residence times of chemical elements in the ocean have been calculated lower than commonly accepted in the literature for several decades. Both changes in salinity and chemistry of seawater took place throughout the Earth’s history at the m.y. timescale. Continents did not emerge before 3 Gy ago, thus excluding the weathering of their surfaces and the transport of alkali and calc-alkali elements by the rivers to the oceans. The only available sources, albeit to a limited extent, were possibly volcanic islands. As sodium is the main cation responsible for seawater salinity, calcium could have contributed to the charge balance of seawater to preclude the development of highly acidic waters. Indeed, the high-temperature hydrothermal alteration of oceanic crust is an important source of calcium that could have accumulated in seawater in the absence of its removal by calcifying organisms. It means that the earliest oceans could have been ‘CaCl2 dominated oceans’ instead of the ‘NaCl dominated oceans’ that prevailed during the Proterozoic and Phanerozoic.","PeriodicalId":55978,"journal":{"name":"Bulletin de la Societe Geologique de France","volume":"11 1","pages":"245-260"},"PeriodicalIF":0.0,"publicationDate":"2016-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84552787","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2016-12-01DOI: 10.2113/GSSGFBULL.187.6.261
J. Bourdier, Marion Auxerre, L. Arbaret, M. Pichavant
Rhyolitic pyroclastic deposits, mostly ignimbrites (ash-and-pumice flow deposits) from plinian eruptions belonging to the early activity (> 2.5 Ma) of the Plio-Quaternary Monts Dore volcanic field (Massif central, France) are documented in order to provide lithofacies and compositional data that could serve as a rational basis for ignimbrite discrimination and tephrostratigraphic correlations. We define or redefine six major pyroclastic units (five ignimbrites and one pumice fallout deposit), based mainly on pumice texture and mineral assemblage. Pumices and quartz-hosted glass inclusions are rather uniform compositionally, being high-silica rhyolites with very low CaO, MgO and FeO contents. Juvenile mineral assemblages are K-feldspar ± quartz ± plagioclase, with rare biotite ± amphibole + accessory phases (mostly sphene, zircon, oxides, apatite). The feldspars, biotite and amphibole compositions of all units strongly overlap and poorly constrain ignimbrite discrimination. These data provide clues to some volcanological issues under debate in the Monts Dore volcanic field. The major rhyolitic pyroclastics found on the Monts Dore margins, e.g. the conspicuous « Grande Nappe » unit of previous authors, are here interpreted as stratigraphical units beneath those exposed in proximal areas, and concealed in the central structural depression (caldera) suggested by previous gravimetric studies. The poorly constrained caldera geometry should be envisioned as a compound, polygenic structure related to several ignimbrite eruptions spanning at least 350 ky, whose vent locations may have shifted with time. The very scarce Fe-Mg silicate phases, biotite and amphibole found in the pumices and ignimbrite matrices show complex compositional populations which can be explained only partly by xenocrystic contamination and require further petrological investigations.
{"title":"Composition and correlation criteria of the rhyolitic ignimbrites in the Monts Dore volcanic field (France)","authors":"J. Bourdier, Marion Auxerre, L. Arbaret, M. Pichavant","doi":"10.2113/GSSGFBULL.187.6.261","DOIUrl":"https://doi.org/10.2113/GSSGFBULL.187.6.261","url":null,"abstract":"Rhyolitic pyroclastic deposits, mostly ignimbrites (ash-and-pumice flow deposits) from plinian eruptions belonging to the early activity (> 2.5 Ma) of the Plio-Quaternary Monts Dore volcanic field (Massif central, France) are documented in order to provide lithofacies and compositional data that could serve as a rational basis for ignimbrite discrimination and tephrostratigraphic correlations. We define or redefine six major pyroclastic units (five ignimbrites and one pumice fallout deposit), based mainly on pumice texture and mineral assemblage. Pumices and quartz-hosted glass inclusions are rather uniform compositionally, being high-silica rhyolites with very low CaO, MgO and FeO contents. Juvenile mineral assemblages are K-feldspar ± quartz ± plagioclase, with rare biotite ± amphibole + accessory phases (mostly sphene, zircon, oxides, apatite). The feldspars, biotite and amphibole compositions of all units strongly overlap and poorly constrain ignimbrite discrimination. These data provide clues to some volcanological issues under debate in the Monts Dore volcanic field. The major rhyolitic pyroclastics found on the Monts Dore margins, e.g. the conspicuous « Grande Nappe » unit of previous authors, are here interpreted as stratigraphical units beneath those exposed in proximal areas, and concealed in the central structural depression (caldera) suggested by previous gravimetric studies. The poorly constrained caldera geometry should be envisioned as a compound, polygenic structure related to several ignimbrite eruptions spanning at least 350 ky, whose vent locations may have shifted with time. The very scarce Fe-Mg silicate phases, biotite and amphibole found in the pumices and ignimbrite matrices show complex compositional populations which can be explained only partly by xenocrystic contamination and require further petrological investigations.","PeriodicalId":55978,"journal":{"name":"Bulletin de la Societe Geologique de France","volume":"8 1","pages":"261-273"},"PeriodicalIF":0.0,"publicationDate":"2016-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82033966","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
V. Riboulot, A. Cattaneo, C. Scalabrin, A. Gaillot, G. Jouet, Grégory Ballas, T. Marsset, S. Garziglia, S. Ker
The Romanian sector of the Black Sea deserves attention because the Danube deep-sea fan is one of the largest sediment depositional systems worldwide and is considered the world's most isolated sea, the largest anoxic water body on the planet and a unique energy-rich sea. Due to the high sediment accumulation rate, presence of organic matter and anoxic conditions, the Black sea sediments offshore the Danube delta is rich in gas and thus shows Bottom Simulating Reflectors (BSR). The cartography of the BSR over the last 20 years, exhibits its widespread occurrence, indicative of extensive development of hydrate accumulations and a huge gas hydrate potential. By combining old and new datasets acquired in 2015 during the GHASS expedition, we performed a geomorphological analysis of the continental slope north-east of the Danube canyon compared with the spatial distribution of gas seeps in the water column and the predicted extent of the gas hydrate stability zone. This analysis provides new evidence of the role of geomorphological setting and gas hydrate extent in controlling the location of the observed gas expulsions and gas flares in the water column. Gas flares are today considered an important source of the carbon budget of the oceans and, potentially, of the atmosphere.
{"title":"Control of the geomorphology and gas hydrate extent on widespread gas emissions offshore Romania","authors":"V. Riboulot, A. Cattaneo, C. Scalabrin, A. Gaillot, G. Jouet, Grégory Ballas, T. Marsset, S. Garziglia, S. Ker","doi":"10.1051/BSGF/2017182","DOIUrl":"https://doi.org/10.1051/BSGF/2017182","url":null,"abstract":"The Romanian sector of the Black Sea deserves attention because the Danube deep-sea fan is one of the largest sediment depositional systems worldwide and is considered the world's most isolated sea, the largest anoxic water body on the planet and a unique energy-rich sea. Due to the high sediment accumulation rate, presence of organic matter and anoxic conditions, the Black sea sediments offshore the Danube delta is rich in gas and thus shows Bottom Simulating Reflectors (BSR). The cartography of the BSR over the last 20 years, exhibits its widespread occurrence, indicative of extensive development of hydrate accumulations and a huge gas hydrate potential. By combining old and new datasets acquired in 2015 during the GHASS expedition, we performed a geomorphological analysis of the continental slope north-east of the Danube canyon compared with the spatial distribution of gas seeps in the water column and the predicted extent of the gas hydrate stability zone. This analysis provides new evidence of the role of geomorphological setting and gas hydrate extent in controlling the location of the observed gas expulsions and gas flares in the water column. Gas flares are today considered an important source of the carbon budget of the oceans and, potentially, of the atmosphere.","PeriodicalId":55978,"journal":{"name":"Bulletin de la Societe Geologique de France","volume":"21 1","pages":"26"},"PeriodicalIF":0.0,"publicationDate":"2016-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77629719","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2016-09-01DOI: 10.2113/GSSGFBULL.187.4-5.187
F. Fournier, A. Tassy, I. Thinon, P. Münch, J. Cornée, J. Borgomano, P. Léonide, M. Beslier, A. Fournillon, C. Gorini, P. Guennoc, J. Oudet, M. Rabineau, F. Sage, R. Toullec
The seaward extension of onshore formations and structures were previously almost unknown in Provence. The interpretation of 2D high-resolution marine seismic profiles together with the integration of sea-bottom rock samples provides new insights into the stratigraphic, structural and paleogeographic framework of pre-Messinian Salinity Crisis (MSC) deposits of the Provence continental shelf. Seven post-Jurassic seismic units have been identified on seismic profiles, mapped throughout the offshore Provence area and correlated with the onshore series. The studied marine surface and sub-surface database provided new insights into the mid and late Cretaceous paleogeography and structural framework as well as into the syn-and post-rift deformation in Provence. Thick (up to 2000 m) Aptian-Albian series whose deposition is controlled by E-W-trending faults are evidenced offshore. The occurrence and location of the Upper Cretaceous South-Provence basin is confirmed by the thick (up to 1500 m) basinal series downlaping the Aptian-Albian unit. This basin was fed in terrigenous sediments by a southern massif (" Massif Meridional ") whose present-day relict is the Paleozoic basement and its sedimentary cover from the Sicie imbricate. In the bay of Marseille, thick syn-rift (Rupelian to Aquitanian) deposition occurred (>1000 m). During the rifting phase, syn-sedimentary deformations consist of dominant N040 to N060 sub-vertical faults with a normal component and N050 drag-synclines and anticlines. The syn-rift and early post-rift units (Rupelian to early Burdigalian) are deformed and form a set of E-W-trending en echelon folds that may result from sinistral strike-slip reactivation of N040 to N060 normal faults during a N-S com-pressive phase of early-to-mid Burdigalian age (18-20 Ma). Finally, minor fault reactivation and local folding affect post-rift deposits within a N160-trending corridor localized south of La Couronne, and could result from a later, post-Burdigalian and pre-Pliocene compressive phase.
{"title":"Pre-Pliocene tectonostratigraphic framework of the Provence continental shelf (eastern Gulf of Lion, SE France)","authors":"F. Fournier, A. Tassy, I. Thinon, P. Münch, J. Cornée, J. Borgomano, P. Léonide, M. Beslier, A. Fournillon, C. Gorini, P. Guennoc, J. Oudet, M. Rabineau, F. Sage, R. Toullec","doi":"10.2113/GSSGFBULL.187.4-5.187","DOIUrl":"https://doi.org/10.2113/GSSGFBULL.187.4-5.187","url":null,"abstract":"The seaward extension of onshore formations and structures were previously almost unknown in Provence. The interpretation of 2D high-resolution marine seismic profiles together with the integration of sea-bottom rock samples provides new insights into the stratigraphic, structural and paleogeographic framework of pre-Messinian Salinity Crisis (MSC) deposits of the Provence continental shelf. Seven post-Jurassic seismic units have been identified on seismic profiles, mapped throughout the offshore Provence area and correlated with the onshore series. The studied marine surface and sub-surface database provided new insights into the mid and late Cretaceous paleogeography and structural framework as well as into the syn-and post-rift deformation in Provence. Thick (up to 2000 m) Aptian-Albian series whose deposition is controlled by E-W-trending faults are evidenced offshore. The occurrence and location of the Upper Cretaceous South-Provence basin is confirmed by the thick (up to 1500 m) basinal series downlaping the Aptian-Albian unit. This basin was fed in terrigenous sediments by a southern massif (\" Massif Meridional \") whose present-day relict is the Paleozoic basement and its sedimentary cover from the Sicie imbricate. In the bay of Marseille, thick syn-rift (Rupelian to Aquitanian) deposition occurred (>1000 m). During the rifting phase, syn-sedimentary deformations consist of dominant N040 to N060 sub-vertical faults with a normal component and N050 drag-synclines and anticlines. The syn-rift and early post-rift units (Rupelian to early Burdigalian) are deformed and form a set of E-W-trending en echelon folds that may result from sinistral strike-slip reactivation of N040 to N060 normal faults during a N-S com-pressive phase of early-to-mid Burdigalian age (18-20 Ma). Finally, minor fault reactivation and local folding affect post-rift deposits within a N160-trending corridor localized south of La Couronne, and could result from a later, post-Burdigalian and pre-Pliocene compressive phase.","PeriodicalId":55978,"journal":{"name":"Bulletin de la Societe Geologique de France","volume":"42 1","pages":"187-215"},"PeriodicalIF":0.0,"publicationDate":"2016-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91330374","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2016-09-01DOI: 10.2113/GSSGFBULL.187.4-5.217
J. Benoit
Euchambersia mirabilis is unique amongst Permo-Triassic therapsids because it has an external maxillary fossa associated with a ridged canine. This anatomy led to the commonly accepted conclusion that the fossa accommodated a venom gland, which would make Euchambersia the earliest known venomous land vertebrate. Indeed, Euchambersia is considered to be the most robustly supported case of an extinct venomous species and serves as a model for infering envenoming capacity in fossil species. Here, a review of the literature on Euchambersia , with special emphasis on canine morphology, shows that this hypothesis is often based on inaccurate drawings of the canine and, for post-1986 authors, it is even based on the assumption that the canine of Euchambersia is grooved, whereas it is actually only ridged. This does not invalidate the venomous therocephalian hypothesis, but nevertheless emphasizes the critical importance of first hand observations of original material for any type of work in vertebrate paleontology. This review offers an interesting example of how observations and the resulting scientific hypotheses interact, grow, and can reciprocally influence each other.
{"title":"A review of the “venomous therocephalian” hypothesis and how multiple re-portrayals of Euchambersia have influenced its success and vice versa","authors":"J. Benoit","doi":"10.2113/GSSGFBULL.187.4-5.217","DOIUrl":"https://doi.org/10.2113/GSSGFBULL.187.4-5.217","url":null,"abstract":"Euchambersia mirabilis is unique amongst Permo-Triassic therapsids because it has an external maxillary fossa associated with a ridged canine. This anatomy led to the commonly accepted conclusion that the fossa accommodated a venom gland, which would make Euchambersia the earliest known venomous land vertebrate. Indeed, Euchambersia is considered to be the most robustly supported case of an extinct venomous species and serves as a model for infering envenoming capacity in fossil species. Here, a review of the literature on Euchambersia , with special emphasis on canine morphology, shows that this hypothesis is often based on inaccurate drawings of the canine and, for post-1986 authors, it is even based on the assumption that the canine of Euchambersia is grooved, whereas it is actually only ridged. This does not invalidate the venomous therocephalian hypothesis, but nevertheless emphasizes the critical importance of first hand observations of original material for any type of work in vertebrate paleontology. This review offers an interesting example of how observations and the resulting scientific hypotheses interact, grow, and can reciprocally influence each other.","PeriodicalId":55978,"journal":{"name":"Bulletin de la Societe Geologique de France","volume":"20 1","pages":"217-224"},"PeriodicalIF":0.0,"publicationDate":"2016-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75361309","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2016-09-01DOI: 10.2113/GSSGFBULL.187.4-5.225
B. Bourel, Jean‐David Moreau, Vincent Trincal, Anne-Véronique Walter-Simonnet
Tufas bearing plant macroremains are uncommon in the Causses Basin (southern France). Here, we report a new fossiliferous tufa deposits at Mende, in Lozere. This palaeontological site is the first Quaternary tufa from the northern part of the Causses Basin that yields such an abundance of plant macroremains. The radiocarbon dating shows that these Holocene deposits are related to the Atlantic period. Geomorphology and mineralogy show that the plant-bearing deposit is a calcareous tufa only composed by calcite, deposited near to an outlet of cool water, linked to the karstic hydrological system of the Causse de Mende. The flora exposed in this article is dominated by angiosperms. Leaves and reproductive structures were assigned to Acer platanoides, Corylus sp., Hedera sp., Salix cf. cinerea, and Tilia cordata. This new palaeobotanical data complements our scarcely knowledge of the Atlantic floras from the Causses Basin. During the Atlantic period, and in the northern part of the basin, whereas Pinus-dominated forests and oak groves were probably well-developed, valleys were locally inhabited by diversified wet angiosperm-dominated forests.
{"title":"Fossiliferous Holocene tufa of Mende (Lozère, southern France): implication for the Atlantic vegetation of the Causses Basin","authors":"B. Bourel, Jean‐David Moreau, Vincent Trincal, Anne-Véronique Walter-Simonnet","doi":"10.2113/GSSGFBULL.187.4-5.225","DOIUrl":"https://doi.org/10.2113/GSSGFBULL.187.4-5.225","url":null,"abstract":"Tufas bearing plant macroremains are uncommon in the Causses Basin (southern France). Here, we report a \u0000new fossiliferous tufa deposits at Mende, in Lozere. This palaeontological site is the first Quaternary tufa from the \u0000northern part of the Causses Basin that yields such an abundance of plant macroremains. The radiocarbon dating shows \u0000that these Holocene deposits are related to the Atlantic period. Geomorphology and mineralogy show that the \u0000plant-bearing deposit is a calcareous tufa only composed by calcite, deposited near to an outlet of cool water, linked to \u0000the karstic hydrological system of the Causse de Mende. The flora exposed in this article is dominated by angiosperms. \u0000Leaves and reproductive structures were assigned to Acer platanoides, Corylus sp., Hedera sp., Salix cf. cinerea, and \u0000Tilia cordata. This new palaeobotanical data complements our scarcely knowledge of the Atlantic floras from the Causses \u0000Basin. During the Atlantic period, and in the northern part of the basin, whereas Pinus-dominated forests and oak \u0000groves were probably well-developed, valleys were locally inhabited by diversified wet angiosperm-dominated forests.","PeriodicalId":55978,"journal":{"name":"Bulletin de la Societe Geologique de France","volume":"115 3","pages":"225-235"},"PeriodicalIF":0.0,"publicationDate":"2016-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72589652","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2016-05-01DOI: 10.2113/GSSGFBULL.187.3.155
H. Ouanaimi, A. Soulaimani, C. Hoepffner, A. Michard, L. Baidder
The transition from the Cambrian to Ordovician in Morocco is known to be characterized by a frequent Furongian hiatus, restricted extension of the Tremadocian marine deposits, and frequent unconformities at the base of the transgressive upper Floian deposits. In the present work, we first highlight the occurrence of Fe- and mica-rich, red silty/sandy formations in the Central and Eastern High Atlas between the Middle Cambrian and Upper Floian sequences. In the Tislyt type-locality, a synsedimentary hemigraben structure is defined, within which the red beds show frequent slump folds, debris flows and internal unconformities. The correlation with several coeval series of the Meseta domain allows us to define a shallow marine, ferruginous clastic Atlas-Meseta Red Beds (AMRB) basin during the Tremadocian-early Floian. The AMRB basin extended between the Meseta coastal block and the Anti-Atlas domain, being limited by the fault zones that became the West Meseta shear zone and the South Meseta fault, respectively, in the Variscan orogen. The AMRB basin compares with the coeval rifted basins of the central Iberian and Armorican massifs. The red beds were likely sourced from the east, from both the Precambrian basement and Early Ordovician magmatic rocks, contrary to the Ordovician deposits of the Sahara platform sourced from the south. Subsidence of the AMRB and central Iberian-Armorican basins of the NW-Gondwana border aborted during the Floian, whereas the opening of the Rheic ocean went on more to the west.
{"title":"The Atlas-Meseta Red Beds basin (Morocco) and the Lower Ordovician rifting of NW-Gondwana","authors":"H. Ouanaimi, A. Soulaimani, C. Hoepffner, A. Michard, L. Baidder","doi":"10.2113/GSSGFBULL.187.3.155","DOIUrl":"https://doi.org/10.2113/GSSGFBULL.187.3.155","url":null,"abstract":"The transition from the Cambrian to Ordovician in Morocco is known to be characterized by a frequent Furongian hiatus, restricted extension of the Tremadocian marine deposits, and frequent unconformities at the base of the transgressive upper Floian deposits. In the present work, we first highlight the occurrence of Fe- and mica-rich, red silty/sandy formations in the Central and Eastern High Atlas between the Middle Cambrian and Upper Floian sequences. In the Tislyt type-locality, a synsedimentary hemigraben structure is defined, within which the red beds show frequent slump folds, debris flows and internal unconformities. The correlation with several coeval series of the Meseta domain allows us to define a shallow marine, ferruginous clastic Atlas-Meseta Red Beds (AMRB) basin during the Tremadocian-early Floian. The AMRB basin extended between the Meseta coastal block and the Anti-Atlas domain, being limited by the fault zones that became the West Meseta shear zone and the South Meseta fault, respectively, in the Variscan orogen. The AMRB basin compares with the coeval rifted basins of the central Iberian and Armorican massifs. The red beds were likely sourced from the east, from both the Precambrian basement and Early Ordovician magmatic rocks, contrary to the Ordovician deposits of the Sahara platform sourced from the south. Subsidence of the AMRB and central Iberian-Armorican basins of the NW-Gondwana border aborted during the Floian, whereas the opening of the Rheic ocean went on more to the west.","PeriodicalId":55978,"journal":{"name":"Bulletin de la Societe Geologique de France","volume":"31 2","pages":"155-168"},"PeriodicalIF":0.0,"publicationDate":"2016-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72562257","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2016-05-01DOI: 10.2113/GSSGFBULL.187.3.169
G. Dufrechou, A. Hohmann, A. Bourguignon, G. Grandjean
Short-wave infrared (SWIR: 1100–2500 nm) reflectance spectra of soil samples, acquired under laboratory-controlled conditions, were used to estimate the swelling potentials of the soils and to use SWIR spectroscopy to improve a part of the swelling-risk map of France. A total of 332 samples were collected to the west of Orleans (France) in various geological formations and swelling-risk areas and along two (eastern and western) transects with different samples spacings. Comparisons between the swelling potentials of the soils and the swelling-risk areas of the map exhibit good correlation in the south of the sampling area; however, there are several inconsistencies in the north of the study area that highlight the necessity of locally redrawing the accepted swelling-risk map of France. The sampling interval (approximately 260 m) along the eastern transect was too sparse and does not appear to have effectively captured the smallest and/or isolated lithologies. The sampling interval along the western transect (approximately 50 m) revealed the presence of an unmapped swelling-potential zone, which was confirmed by several soil samples. The sample interval along the western transect appears to be more suitable for mapping the smallest lithologies. The presence of several samples in close proximity that exhibit the same swelling potential is a robust indication of the presence of a zone with constant swelling potential. A new swelling-risk map of the sampling area was produced based on the soil samples. The map produced by interpolation did not permit the representation of discrete lithological units, introduced spurious swelling-risk zones that however could be representative of tillage in agricultural zones. More samples are therefore needed to produce a reliable map on the scale of the sampling area. According to swelling potential uncertainty related to soil sampling and soil treatment, spectroscopy-based approach proposed here cannot be used to replace the existing swelling-risk map of France. This method permits however the rapid and low-cost estimation of the swell potentials of a large number of samples, which could be used at regional-scale to target areas where doubt remains or where infrastructure damages attributed to swelling behavior are known. At local scale, soil samples need to be properly and laboratory treated to accurately produce local revised and detailed swelling-risk maps.
{"title":"Targeting and mapping expansive soils (Loiret, France): geometrical analysis of laboratory soil spectra in the short-wave infrared domain (1100–2500 nm)","authors":"G. Dufrechou, A. Hohmann, A. Bourguignon, G. Grandjean","doi":"10.2113/GSSGFBULL.187.3.169","DOIUrl":"https://doi.org/10.2113/GSSGFBULL.187.3.169","url":null,"abstract":"Short-wave infrared (SWIR: 1100–2500 nm) reflectance spectra of soil samples, acquired under laboratory-controlled conditions, were used to estimate the swelling potentials of the soils and to use SWIR spectroscopy to improve a part of the swelling-risk map of France. A total of 332 samples were collected to the west of Orleans (France) in various geological formations and swelling-risk areas and along two (eastern and western) transects with different samples spacings. Comparisons between the swelling potentials of the soils and the swelling-risk areas of the map exhibit good correlation in the south of the sampling area; however, there are several inconsistencies in the north of the study area that highlight the necessity of locally redrawing the accepted swelling-risk map of France. The sampling interval (approximately 260 m) along the eastern transect was too sparse and does not appear to have effectively captured the smallest and/or isolated lithologies. The sampling interval along the western transect (approximately 50 m) revealed the presence of an unmapped swelling-potential zone, which was confirmed by several soil samples. The sample interval along the western transect appears to be more suitable for mapping the smallest lithologies. The presence of several samples in close proximity that exhibit the same swelling potential is a robust indication of the presence of a zone with constant swelling potential. A new swelling-risk map of the sampling area was produced based on the soil samples. The map produced by interpolation did not permit the representation of discrete lithological units, introduced spurious swelling-risk zones that however could be representative of tillage in agricultural zones. More samples are therefore needed to produce a reliable map on the scale of the sampling area. According to swelling potential uncertainty related to soil sampling and soil treatment, spectroscopy-based approach proposed here cannot be used to replace the existing swelling-risk map of France. This method permits however the rapid and low-cost estimation of the swell potentials of a large number of samples, which could be used at regional-scale to target areas where doubt remains or where infrastructure damages attributed to swelling behavior are known. At local scale, soil samples need to be properly and laboratory treated to accurately produce local revised and detailed swelling-risk maps.","PeriodicalId":55978,"journal":{"name":"Bulletin de la Societe Geologique de France","volume":"14 1","pages":"169-181"},"PeriodicalIF":0.0,"publicationDate":"2016-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81784897","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2016-05-01DOI: 10.2113/GSSGFBULL.187.3.133
Y. Hamon, R. Deschamps, P. Joseph, D. Garcia, E. Chanvry
This article is a first attempt of combining sedimentological analysis and geochemical systematics of the Alveolina Limestone Formation as a tool to identify the major stratigraphic surfaces, and to improve the sequence stratigraphy interpretation. This formation is Early Eocene in age and crops out in several well-exposed cliffs in the Serraduy – Roda de Isabena area (Graus-Tremp basin, NE Spain). Within this succession, nineteen carbonate and siliciclastic facies have been identified and grouped in environmental facies associations (based on their vertical stacking and lateral relationships) : 1) coastal plain; 2) clastic deltaic complex; 3) shallow carbonate inner-ramp; 4) midramp; 5) outer-ramp; 6) reefal facies. The depositional architectures studied in the Serraduy area can be directly assessed on the field, and a 3D reconstruction is proposed. This enables us to build a synthetic depositional model and to identify five small-scale T/R cycles, bounded by different kinds of sedimentary discontinuities : angular unconformity, firmground, erosional surface… In parallel, geochemical analyses (C and O isotopes, major, minor and trace elements) were carried out to help at hierarchizing the cycles and the boundaries previously identified. Four of them may be considered as major stratigraphic surfaces, corresponding either to regional-scale angular unconformities, or to exposure surfaces. The latter are characterized by a selective dissolution, a slight but sharp decrease in δ13 CV-PDB and in Mg, Fe and Sr contents below the surface. The absence of typical sedimentary criteria of exposure (with the exception of these geochemical signatures) may be explained by short-term exposure, an arid to semi-arid climate, and a dominant low-magnesian calcite original mineralogy, precluding the development and the preservation of widespread vadose diagenetic products. A new sequence stratigraphy model for the Alveolina Limestone Fm is finally proposed and discussed.
本文首次尝试将沉积学分析与地球化学系统学相结合，作为识别主要地层面、完善层序地层学解释的工具。在serrady - Roda de Isabena地区(grausu - tremp盆地，西班牙东北部)，这组地层为早始新世，在几个暴露良好的悬崖上生长。在这一演替中，已经确定了19种碳酸盐岩和硅质碎屑相，并将其归类为环境相组合(基于它们的垂直堆叠和横向关系):1)沿海平原;2)碎屑三角洲杂岩;3)浅层碳酸盐岩内斜坡;4) midramp;5) outer-ramp;礁相;serraday地区研究的沉积构型可以直接在现场进行评价，并提出了三维重建方法。这使我们能够建立一个合成的沉积模型，并确定了5个小尺度的T/R旋回，由不同类型的沉积不连续面所包围:角不整合面、坚实面、侵蚀面……同时，进行了地球化学分析(C和O同位素，主要、次要和微量元素)，以帮助对旋回和先前确定的边界进行分层。其中4个可被认为是主要的地层面，或对应于区域尺度的角不整合面，或对应于暴露面。后者的特征是选择性溶解，δ13 CV-PDB和表面以下Mg、Fe和Sr含量略有但急剧下降。缺乏典型的沉积暴露标准(除这些地球化学特征外)可能是由于短期暴露、干旱至半干旱气候和主要的低镁方解石原始矿物学，阻碍了广泛的渗透成岩产物的发育和保存。最后提出并讨论了一种新的阿尔泡利纳灰岩组层序地层学模型。
{"title":"New insight of sedimentological and geochemical characterization of siliciclastic-carbonate deposits (Alveolina Limestone Formation, Graus-Tremp basin, Spain)","authors":"Y. Hamon, R. Deschamps, P. Joseph, D. Garcia, E. Chanvry","doi":"10.2113/GSSGFBULL.187.3.133","DOIUrl":"https://doi.org/10.2113/GSSGFBULL.187.3.133","url":null,"abstract":"This article is a first attempt of combining sedimentological analysis and geochemical systematics of the Alveolina Limestone Formation as a tool to identify the major stratigraphic surfaces, and to improve the sequence stratigraphy interpretation. This formation is Early Eocene in age and crops out in several well-exposed cliffs in the Serraduy – Roda de Isabena area (Graus-Tremp basin, NE Spain). Within this succession, nineteen carbonate and siliciclastic facies have been identified and grouped in environmental facies associations (based on their vertical stacking and lateral relationships) : 1) coastal plain; 2) clastic deltaic complex; 3) shallow carbonate inner-ramp; 4) midramp; 5) outer-ramp; 6) reefal facies. The depositional architectures studied in the Serraduy area can be directly assessed on the field, and a 3D reconstruction is proposed. This enables us to build a synthetic depositional model and to identify five small-scale T/R cycles, bounded by different kinds of sedimentary discontinuities : angular unconformity, firmground, erosional surface… In parallel, geochemical analyses (C and O isotopes, major, minor and trace elements) were carried out to help at hierarchizing the cycles and the boundaries previously identified. Four of them may be considered as major stratigraphic surfaces, corresponding either to regional-scale angular unconformities, or to exposure surfaces. The latter are characterized by a selective dissolution, a slight but sharp decrease in δ13 CV-PDB and in Mg, Fe and Sr contents below the surface. The absence of typical sedimentary criteria of exposure (with the exception of these geochemical signatures) may be explained by short-term exposure, an arid to semi-arid climate, and a dominant low-magnesian calcite original mineralogy, precluding the development and the preservation of widespread vadose diagenetic products. A new sequence stratigraphy model for the Alveolina Limestone Fm is finally proposed and discussed.","PeriodicalId":55978,"journal":{"name":"Bulletin de la Societe Geologique de France","volume":"12 1","pages":"133-153"},"PeriodicalIF":0.0,"publicationDate":"2016-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78516615","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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