Defining geo-habitats for groundwater ecosystem assessments: an example from England and Wales (UK)     

Damiano C. Weitowitz  Louise Maurice  Melinda Lewis  John P. Bloomfield  Julia Reiss  Anne L. Robertson 《Hydrogeology Journal》2017,25(8):2453-2466

Groundwater ecosystems comprising micro-organisms and metazoans provide an important contribution to global biodiversity. Their complexity depends on geology, which determines the physical habitat available, and the chemical conditions within it. Despite this, methods of classifying groundwater habitats using geological data are not well established and researchers have called for higher resolution habitat frameworks. A novel habitat typology for England and Wales (UK) is proposed, which distinguishes 11 geological habitats (geo-habitats) on hydrogeological principles and maps their distribution. Hydrogeological and hydrochemical data are used to determine the characteristics of each geo-habitat, and demonstrate their differences. Using these abiotic parameters, a new method to determine abiotic habitat quality is then developed. The geo-habitats had significantly different characteristics, validating the classification system. All geo-habitats were highly heterogeneous, containing both high quality habitat patches that are likely to be suitable for fauna, and areas of low quality that may limit faunal distributions. Karstic and porous habitats generally were higher quality than fractured habitats. Overall, 70% of England and Wales are covered by lower quality fractured habitats, with only 13% covered by higher quality habitats. The main areas of high quality habitats occur in central England as north–south trending belts, possibly facilitating dispersal along this axis. They are separated by low quality geo-habitats that may prevent east-west dispersal of fauna. In south-west England and Wales suitable geo-habitats occur as small isolated patches. Overall, this paper provides a new national-scale typology that is adaptable for studies in other geographic areas.  相似文献   

Les orthogneiss calco-alcalins de Foumban–Bankim : témoins d'une zone interne de marge active panafricaine en cisaillement     

Emmanuel Njonfang  Vincent Ngako  Maurice Kwekam  Pascal Affaton 《Comptes Rendus Geoscience》2006,338(9):606-616

The mylonitic rocks of the Central Cameroonian Shear Zone (Foumban–Bankim sector) are mainly ancient magmatic rocks emplaced in an internal zone of a Pan-African active margin. They display calc-alkaline affinities with granitoids of northern Cameroon, but differ by their higher K contents and shoshonitic nature. This spatial distinction in pre- to syn-orogenic magmatism permits to define a north to south potassium increase trend, compatible with the existence of a northern Pan-African subduction zone. The shearing evolution of this margin is marked by the superposition of two mylonitic foliations and the occurrence of unusual δ-type porphyroclasts. This suggests the interference of two shearing phases operating in opposing sense at a constant direction, under deep and shallow metamorphic conditions, respectively. To cite this article: E. Njonfang et al., C. R. Geoscience 338 (2006).  相似文献   

Exhumation cénozoı̈que des massifs du Canigou et de Mont-Louis (Pyrénées orientales,France)Cainozoic exhumation of the Canigou and Mont-Louis massifs (eastern Pyrenees,France)     

Olivier Maurel  Maurice Brunel  Patrick Monié 《Comptes Rendus Geoscience》2002,334(12):941-948

The onset of exhumation of the Canigou massif, related to the reactivation of the Têt Fault during the Gulf of Lion opening, is dated at 26–27 Ma, using apatite fission track method and lasts until the Aquitanian, at a rate of $\text{0.29±0.07 }\text{mm}\text{yr}{}^{\mathrm{?1}}$. The subsequent evolution is necessarily followed by a slower rate of exhumation to account for total exhumation. At the hanging-wall of this fault, the granite of Mont-Louis records an older exhumation history, where the crossing of the 110 °C isotherm at 40±4 Ma is related to the Pyrenean thrusting. To cite this article: O. Maurel et al., C. R. Geoscience 334 (2002) 941–948.  相似文献   

Reviews     

Peter R. Odell  Seiya Uyeda  V. P. Zenkovich  C. Koeman  Johannes Ulrich  Maurice K.-Seguin  K. Gerke  U. Vetter  G. T. W. Wittmann  H. J. Habing  J. Gentilli 《GeoJournal》1977,1(1):95-100

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Sismique marine haute résolution 3D : un nouvel outil de reconnaissance à destination de la communauté scientifique     

Yannick Thomas  Bruno Marsset  Stéphane Didailler  Jean-Pierre Regnault  Sandie Le Conte  Dominique Le Roux  Patrick Farcy  Maurice Magueur  Pascal Viollette  Jacques Herveou  Jean-Charles Guedes  Bernard Jegot  Gilles Gascon  Christian Prud&#x;homme  Hervé Nouze  Estelle Thereau  Isabelle Contrucci  Jean-Paul Foucher 《Comptes Rendus Geoscience》2004,336(6):579-585

This note presents the first results of the development of 3D high-resolution marine seismic method designed for scientific application. A particular attention was paid to the realisation of an operational system to be in agreement with the expected goals in term of acquisition and processing. To cite this article: Y. Thomas et al., C. R. Geoscience 336 (2004).  相似文献   

UPb emplacement and 40Ar/39Ar cooling ages of the eastern Mont-Louis granite massif (Eastern Pyrenees,France)     

Olivier Maurel  Jean-Patrick Respaut  Patrick Monié  Nicolas Arnaud  Maurice Brunel 《Comptes Rendus Geoscience》2004,336(12):1091-1098

Zircon UPb dating by SIMS of the Mont-Louis granite yields an age of 305±5 Ma, intrepreted to reflect the igneous emplacement age of the massif. It is in agreement with the Hercynian syntectonic character of Pyrenees granite. ⁴⁰Ar/³⁹Ar on hornblende, biotite and K-feldspar permit, to estimate the massif cooling. A rapid temperature decrease (≈30 °C/Ma) is revealed from Westphalian to Late Stephanian, coeval with the emplacement of a laccolithe in the upper crust. Then, the cooling rate decreases to ≈1 °C/Ma. This would be consistent with a long time residence for the pluton from the Late Palaeozoic to the Early Cainozoic at 6–8 km depth. To cite this article: O. Maurel et al., C. R. Geoscience 336 (2004).  相似文献   

Commentaire à la publication de Robin Lacassin et al. intitulée : Was the Trévaresse Thrust the source of the 1909 Lambesc (Provence,France) earthquake ? Historical and geomorphic evidence     

Maurice Mattauer 《Comptes Rendus Geoscience》2002,334(7):513-514

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Magnetostratigraphy of Tertiary Rocks from Maoming Basin,Guangdong Province,China     

Wang Junda  Li Huamei  Zhu Zhaoyu  Maurice K. Seguin  Yang Junfa  Zhang Guomei 《中国地球化学学报》1994,13(2):165-175

The Maoming Basin is one amongst a group of Cretaceous-Tertiary basins in South China-347 samples were collected from drill cores MR and MB and section MS (110° 54′ E. 21° 45′ N). Most of the lithological units are of Tertiary age. The cores include the Laohuling. Shangcun, Huangniuling and Youganwo formations. The MR core (874m in length) has recorded the polarity history from Normal Zone 18 to Normal Zone 11 on the Geomagnetic Polarity Time Scale (GPTS). The strata were formed from about 42Ma to 32Ma, that is from Late Eocene to Early Oligocene. A mean sedimentation rate of this stratigraphic column is 8.1 cm/ka.  相似文献   

Effusive natrocarbonatite activity of Oldoinyo Lengai,June 1988     

Jörg Keller  Maurice Krafft 《Bulletin of Volcanology》1990,52(8):629-645

Oldoinyo Lengai in the Tanzanian rift valley is the only active carbonatite volcano in the world and its natrocarbonatitic lavas are unique in composition. The characteristics of effusive natrocarbonatite activity in June 1988 were studied and fresh samples were directly collected from active carbonatitic lava lakes and flows. Analyses of these samples provide the first information on natrocarbonatites since these unusual volcanic rock type was first described from the 1960–1961 eruptions. The analytical results constrain the original chemistry of fresh natrocarbonatite. Temperatures in lava lakes and of carbonatite lava flows range 491–544°C. The natrocarbonatite lava is extremely fluid at these temperatures and reaches incandescence. The most common variety of natrocarbonatite is porphyritic with abundant phenocrysts of nyerereite (Na_0.82K_0.19)₂(Ca, Sr, Ba)_0.975(CO₃)₂ and gregoryite Na_1.74K_0.1(Ca, Sr, Ba)_0.16CO₃, with complex substitution of (CO₃)^2- by (SO₄)^2-, (PO₄)^3-, F^-, and Cl^-. A phenocryst-poor to aphyric natrocarbonatite variety reflects residual liquids separating from the crystal-rich porphyritic flows. Sylvite, fluorite, and Fe-alabandite (Mn_0.7Fe_0.3S) have been identified as additional primary magmatic phases. Rare phases in the matrix are witherite (BaCO₃) and sellaite (MgF₂). Sylvite and gregoryite, and to a lesser extent nyerereite, are water-soluble and are responsible for the immediate decomposition and chemical alteration of natrocarbonatites under atmospheric conditions. A peralkaline combeite-bearing nephelinite lava is closely related to the natrocarbonatite activity, and is isotopically indistinguishable. It is likely that these two magma compositions are related by liquid immiscibility. The unusual hyperalkaline composition of both magma types makes Oldoinyo Lengai an exotic volcano, and its carbonatites have extreme compositions, and are not representative of carbonatites in general.  相似文献   

Charriage crustal,anatexie et decrochements ductiles dans les Maures orientales (Var,France) au cours de l'orogenese varisque     

Par Alain Vauchez  Maurice Bufalo 《International Journal of Earth Sciences》1988,77(1):45-62

The kinematics of the deformational events recorded in the catazonal gneisses within the eastern part of the Maures massif (Variscan basement of Provence, southeastern France) has been established. These events can be correlated with both the metamorphic and the magmatic evolution, and the orogenic history of the eastern Maures then consists of the following stages:

1. -HP-metamorphism preserved only in relict eclogites and quartzites rich in calc-silicates,
2. -Catazonal metamorphism involving anatectic melting, broadly contemporaneous with large-scale horizontal transport towards the NNE. During this event, the lithologic units were disrupted and intensively mylonitized.
3. -Intrusion of a first generation of anatectic granitoids.
4. -A second tectonic event under epi-to mesozonal metamorphism conditions is responsible for the northward displacement of the eastern Maures relative to the western part along a sinistral strike-slip fault 4 km wide (Ramatuelle — Plan de la Tour fault) in which the early anatectic granitoids have been mylonitized. Outside the fault zone, this event is marked by upright to W-vergent open folds trending N-S, i.e. parallel to the transport direction.
5. -A moderate cataclastic reactivation of the Ramatuelle — Plan de la Tour fault with a dextral sense of shear, locally accompanied in the eastern part of the area by minor lowtemperature thrusting towards the south.
6. -Intrusion of a second generation of anatectic granites about 320 Ma ago.

The metamorphic, magmatic and tectonic evolution of the eastern Maures suggests a continuous orogenic history in an area of rapid crustal thickening by large-scale thrusting within the continental crust. This evolution may be related to the development of continental subduction during the continent/continent collision responsible for the Variscan orogeny in southern Europe.  相似文献