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- SOMMAIRE/SUMMARY 1995 - TOME 321 - SERIE II a - N° 8
- CONTENTS 1995 - TOME 321 - SERIE II a - N° 8
- .......... Page(s) .......... 643
- Réunion Island is located directly above a lithospheric weakness zone trending N120°. The volcanoes Pitons des Neiges and de la Fournaise have been built along this tectonic axis. A large structure of inverse magnetization was found on this N120° axis on the south-eastern flank of La Fournaise. A major fracture zone cuts the edifice of La Fournaise from the south-east to the north-east. Most of the eruptions take place there. From 1950 to 1994, N120° eruptions that occurred indicate that the end of each effusive cycle followed by several years of inactivity. The evolution of the eruptive activity is controlled by the regional stress field pattern and the local stress field pattern induced by La Fournaise. Keywords: Réunion, France, Lithospheric weakness, Fracture zones, Eruptive cycles.
- GEOMATERIALS
- (Mineralogy)
- In the weathering zone of the Pb-Zn-Ba Canoas mine, phlogopites change into chlorites with Zn enrichment, resulting in true Zn-chlorites with 15 to 20% ZnO. This chlorite takes the place of phlogopite in the ore. The further weathering transformation is the corrosion or the substitution of chlorite crystals by smithsonite. Zn-chlorite (Zn 3.48 Mg 5.11 Fe 3.71 Al 0.08 ) (Si 5.67 Al 2.33 ) O 20 (OH) 16 , is very different from the baileychlore. Keywords: Pb-Zn ore, Zn-chlorite, Weathering blanket, Phlogopite, Smithsonite, Gossan.
- GEOCHEMISTRY
- Zoobathymetry and chemical content in the ossicle calcite of crinoid stalk, Michel ROUX, Maurice RENARD, Nadia AMEZIANE and Laurent EMMANUEL ( see Tome 321, Series II a, 1995, p. 675).
- SURFACE GEOSCIENCES
- (Paleoclimatology)
- The high-resolution pollen record of the Semaforo section (Southern Italy, 39°N, 16°42'E) documents major vegetation changes in the southern Italian mountains from 2.4 to 2.1 Ma. A strong decrease of Taxodiaceae forest and development of the steppic element Artemisia after 2.3 Ma, expansion of temperate forest (around 2.25 Ma) and high elevation forest (around 2.18 Ma) reflect a cooler and drier climate. These vegetation changes in Southern Italy correspond to one of the last steps before the disappearance of subtropical plants from the Mediterranean area. Keywords: Palynology, Late Pliocene, Italy, Mediterranean, Palaeovegetation, Palaeoclimatology.
- (Paleoenvironment)
- Studied since the XIXth century, the Lez travertines (Montpellier) have not up to now been mapped in any detail. This multidisciplinary study with 230 Th/ 234 U isotopic data shows that the Castelnau-le-Lez travertines are diachronic. There are three great phases of travertine deposits which allowed gouging by the Lez during the Upper Pleistocene. Keywords: Travertines, 230 Th/ 234 U ages, Palaeovegetation, Upper Pleistocene.
- .......... Page(s) .......... 675
- The chemical composition of skeletal calcite in the stem of living pentacrinid crinoids (Echinodermata) collected at depths from 100 to 1,000 m in the Pacific Ocean was analyzed. A correlation between the biotope depth and Mg content or carbon isotope ratios in the columnal calcite appears. The respective role of temperature, food supply, growth rate and adaptive strategy is discussed. Keywords: Biogeochemistry, Magnesium, Carbon stable isotopes, Bathymetry, Stalked crinoids, Echinodermata.
- .......... Page(s) .......... 681
- The study of the Berriasian Calpionellid succession in some selected sections from the Prérif and Mésorif areas, under marl and limestone interbedding facies, has led to the characterization of the successive Calpionellid zones and subzones. New detailed biostratigraphic data for zones B and C have allowed subdivision of zone B into three (B1, B2 and B3) and zone C into two subzones (C1 and C2). The three subzones already known for zone D (D1, D2 and D3) have also been well characterized. Keywords: Stratigraphy, Berriasian, Calpionellids, Rif, Morocco.
- PALEONTOLOGY
- (Invertebrate Paleontology)
- Changes in associations of conodont genera or biofacies occur rapidly and synchronously during time ranges less than a conodont zone. Resolution obtained with evolution of biofacies changes is better and allows the determination of the base of the Upper Kellwasser event in an environment where it is not distinguished lithologically and the attribution of an age to non fossiliferous sediments. Keywords : Upper Devonian, Frasnian/Famennian, Kellwasser event, Conodonts, Biofacies, Montagne Noire.
- (Vertebrate Paleontology)
- Excavations led since 1989 on a Maastrichtian bone-bed at Campagne-sur-Aude (Aude department, France) have yielded many disarticulated remains of a new sauropod dinosaur. The new taxon Ampelosaurus atacis is preliminarily described, and referred to the family Titanosauridae. It is compared to other European titanosaurids. This discovery confirms the diversity of titanosaurid dinosaurs in the Maastrichtian of Europe. Keywords: Dinosauria, Sauropoda, Titanosauridae, Ampelosaurus atacis, Maastrichtian, France.
- (Human Paleontology)
- On radiographic tracings reduced to natural size of 51 young leucoderm adults, 6 cutaneous segments and 5 bony segments of sagittal profile, were measured in each sex. An analysis by canonical correlations was conducted for calculation of the value and likelihood of retained coefficients (only one in female subjects), but two in males. Multiple regression equations were established between each of the 2 canonical variables (bony and cutaneous) and for each of the sexes. A third analysis concerning the two sexes together showed, by a discriminant function performed in the plane of the canonical variables, that the rate of misclassed subjects stays high (27.5%) with only one significant coefficient. Correlations between canonical variables and the primitive ones showed that the profile as a whole presents preferential relations with the upper lip in females, and the lower lip in males, and the incisive zone and the two lips in the entire population. Keywords: Canonical correlations, Facial profile, Young adult, Sexual differences.
- (Paleoecology)
- .......... Page(s) .......... 705
- The study of the lacustrine infilling from Ribains maar, in the Massif Central, shows a major chronological variability in diatom community, from the end of the lower glacial until the beginning of the early Würm. The transition between the lower glacial and the last interglacial (Eemian), is marked both by a decrease of oligothermic species and the establishment of a eutrophic and eurythermic community. During the Eemian, a first phase is characterized by abundant percentages of planktonic-eutrophic species, next a second phase records the development of a peat bog. Early Würm begins with severe climatic degradation, characterized by the development of a cool water community. Subsequently a warming-up period occurs, indicated by abundant densities of littoral-planktonic species, which precede high values of planktonic-eutrophic species. Keywords: Palaeoecology, Diatoms, Eemian, Lacustrine sediments, Massif Central.
- .......... Page(s) .......... 713
- The Les Roches tephra has been defined at Gimeaux. It was emitted by a trachyandesitic volcano (Puy de la Nugère?) at the end of Dryas II, around 12,000 BP. It has directly affected a late Madgalenian living site, Abri Durif at Enval, 30 km to the southeast of its source. Keywords: Tephra, Chaîne des Puys, Trachyandesite, Magdalenian, France.
- SCIENCES DE LA TERRE ET DES PLANETES EARTH & PLANETARY SCIENCES 1995 - Tome 321 - Série II a - N° 8
- .......... Page(s) .......... V-VIII
- .......... Page(s) .......... 643
- Géomatériaux
- (Minéralogie)
- Géosciences de Surface
- (Paléoenvironnement)
- .......... Page(s) .......... 675
- .......... Page(s) .......... 681
- Paléontologie
- (Paléontologie des Invertébrés)
- (Paléontologie des Vertébrés)
- (Paléontologie humaine)
- (Paléoécologie)
- .......... Page(s) .......... 713
. Le dynamisme de la Fournaise est-il contrôlé par l'anisotropie structurale lithosphérique N 120° située sous l'île de la Réunion? Le taux de reconnaissance estimé pour ce document est de 96.69%.
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Le texte affiché peut comporter un certain nombre d'erreurs. En effet, le mode texte de ce document a été généré de façon automatique par un programme de reconnaissance optique de caractères (OCR). Le taux de reconnaissance estimé pour ce document est de 96.69%.
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