Stratigraphic record of thrust propagation, Carboniferous foreland basin, Pyrenees, with emphasis on Pays-de-Sault (France/Spain)     

J.-J. Delvolvé  D. Vachard  P. Souquet 《International Journal of Earth Sciences》1998,87(3):363-372

The Carboniferous culm of the Pays-de-Sault is divided into two diachronous and synshortening series. These series are dated Late Visean (Pic d'Ourtiset series in a northern overthrust unit) and Early Namurian E2 (La Fajolle series in a southern underthrust unit) from an association of foraminifers, algae, and microproblematica identified in clasts of conglomerates. According to structural positions and facies criteria, these two series are interpreted as two turbiditic depocenters which were generated by southward thrust propagation during Late Visean and Early Namurian. At the scale of the Pyrenean Hercynian range, this evolution is consistent with a thrust and depocenter sequence propagating on the wedge-top depozone of a foreland basin system from the northeast (Mouthoumet subpyrenean massif) to the southwest (end of the High Primary Range) during Late Visean to Westphalian C time interval.  相似文献   

Dust Plasma Interactions at Jupiter     

Mihály Horányi 《Astrophysics and Space Science》1998,264(1-4):257-271

This is a review of recent in situ and remote sensing observations, and theoretical advances of our understanding dust plasma interactions in Jupiter's magnetosphere. Dust grains exposed to plasmas and UV radiation collect electrostatic charges and their dynamics can be altered due to electric and magnetic fields. Hence, magnetospheric effects can shape the size and spatial distributions of micron sized and smaller dust grains. The ring/halo region, the dust streams and the captured ring at Jupiter are recent examples where dust plasma interaction effects can best explain the observations. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Detection of the Lower Boundary of Stellar Convective Envelopes from Seismic Data     

Mário J.P.F.G. Monteiro  Jørgen Christensen-Dalsgaard  Michael J. Thompson 《Astrophysics and Space Science》1998,261(1-4):41-42

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The GTC: An Advanced 10m Telescope for the ORM     

J.M. Rodríguez Espinosa  P. Alvarez  F. Sánchez 《Astrophysics and Space Science》1998,263(1-4):355-360

The Gran Telescopio CANARIAS (GTC) is a high performance 10-m class telescope whose construction has been promoted by the IAC (Instituto de Astrofísica de Canarias). It will be installed at the Roque de los Muchachos Observatory (ORM), in the island of La Palma. First light is planned for end-2002. The key science drivers for the project are image quality, operational efficiency and reliability, as emphasized in the Conceptual Design Document which was finished in mid-97. The Preliminary Design is now proceeding on all aspects of the project. The GTC Project is presently funded at the 70% level by Spain. The scientific drives behind the GTC project are described here, as well as the current technical, managerial, and operational baseline. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

CCD Surface Photometry of Nearby Active Galaxies     

M. Sánchez Portal  A.I. Diaz  M. Álvarez Álvarez  Roberto Terlevich  Elena Terlevich  Itziar Aretxaga 《Astrophysics and Space Science》1998,263(1-4):107-110

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Dynamics and Control for a Small Telescope     

J.A. Berná  M. Pérez  G. Bernabeu 《Astrophysics and Space Science》1998,263(1-4):397-400

Our main goal is to determine the dynamic equations of a certain complex system, as is the case of the mechanical system for a small aperture telescope. Causes of this complexity are: the lack of documents about the operation of the elements belonging to the system, and the variation of dynamics with respect to the time and the position of the telescope. To check that we have obtained a valid set of dynamic equations, we will design a computer control system that will implement a self-guide system for the telescope. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

The cold and wet year 1695 — a contemporary German account     

S. Lindgrén  J. Neumann 《Climatic change》1981,3(2):173-187

After describing briefly some of the outstanding features of the uncommonly cold and wet year 1695, one of the coldest years of the Little Ice Age, an annotated translation is presented of a contemporary review of the unusual weather events of the year in Europe. The original was published in 1702 in Frankfurt am Main, Germany, in vol. XIV of the seriesTheatrum Europaeum. The annotation relates to the historical events of the year that were substantially affected by the weather, events to which rather abstruse references are made in the aforementioned contemporary account. In addition to the fact that the contemporary review describes the uncommon weather conditions of 1695, it appears to be the first extended weather review in history.  相似文献   

The last 30,000 years of faunal history within the Grand Canyon, Arizona     

Jim I. Mead 《Quaternary Research》1981,15(3):311-326

The vertebrate fauna of the last 30,000 radiocarbon years in the Grand Canyon is reviewed. Faunas accompanied with 92 ¹⁴C dates have been analyzed from nine cave sites (four systematically excavated) and 50 packrat middens. Reasonably precise chronological and environmental data of late Pleistocene and Holocene age were obtained through dung studies in Rampart, Muav, and Stanton's Caves; from the numerous packrat middens; and from a ringtail refuse deposit in Vulture Cave. The desert tortoise, 8 species of lizards, 12 species of snakes, 68 species of birds, and 33 species of mammals are identified. Extinct animals include the avian carrion feeder, Teratornis merriami, and the mammalian herbivores, Oreamnos harringtoni, Camelops cf. hesternus, Equus sp., and Nothrotheriops shastense. There is no apparent abrupt end to the late Pleistocene as observed in the Grand Canyon fossil faunal or floral record. Animal and plant taxa of the Grand Canyon responded individually to the changes in climate of the last 30,000 yr. Both animal and plant fossil assemblages indicate that a pre-full glacial, a full glacial, and a late glacial woodland community with many less dominant desert taxa were slowly replaced by a Holocene desert community. All woodland taxa were absent from the lower elevations of the Grand Canyon by 8500 yr B.P.  相似文献   

Une méthode globale d'estimation des températures des réservoirs alimentant les sources thermales. Exemple du Massif Central Français     

Gil Michard  Christian Fouillac  Daniel Grimaud  Jérôme Denis 《Geochimica et cosmochimica acta》1981,45(7):1199-1207

A chemical model based on the equilibrium of water with quartz, albite, adularia, calcite, kaolinite or illite, and chlorite can explain the chemical composition of the main groups of hot springs in Massif Central. Temperature is the principal variable for determining this composition. Model temperatures generally agree with those given by classical cation geothermometers (t ? 135–150° C for Vichy. La Bourboule. Evaux and Châteauneuf; t ? 175–180° C for Chaudes Aigues and Saint Nectaire). The model fails to represent the composition of Mont Dore waters: the high temperatures given by classical geothermometers are considered doubtful.  相似文献   

Crystal fractionation and partial melting in the petrogenesis of a Proterozoic high-MgO volcanic suite,Ungava, Québec     

D. M. Francis  A. J. Hynes  J. N. Ludden  J. Bédard 《Contributions to Mineralogy and Petrology》1981,78(1):27-36

There is little concensus on the relative importance of crystal fractionation and differential partial melting to the chemical diversity observed within most types of volcanic suites. A resolution to this controversy is best sought in suites containing high MgO lavas such as the Chukotat volcanics of the Proterozoic Cape Smith foldbelt, Ungava, Quebec. The succession of this volcanic suite consists of repetitive sequences, each beginning with olivine-phyric basalt (19-12 wt% MgO), grading upwards to pyroxene-phyric basalt (12-8 wt% MgO) and then, in later sequences, to plagioclase-phyric basalt (7-4 wt% MgO). Only the olivine-phyric basalts have compositions capable of equilibrating with the upper mantle and are believed to represent parental magmas for the suite. The pyroxene-phyric and plagioclase-phyric basalts represent magmas derived from these parents by the crystal fractionation of olivine, with minor chromite, clinopyroxene and plagioclase. The order of extrusion in each volcanic sequence is interpreted to reflect a density effect in which successively lighter, more evolved magmas are erupted as hydrostatic pressure wanes. The pyroxene-phyric basalts appear to have evolved at high levels in the active part of the conduit system as the eruption of their parents was in progress. The plagioclase-phyric basalts may represent residual liquids expelled from isolated reservoirs along the crust-mantle interface during the late stages of volcanic activity.A positive correlation between FeO and MgO in the early, most basic olivine-phyric basalts is interpreted to reflect progressive adiabatic partial melting in the upper mantle. Although this complicates the chemistry, it is not a significant factor in the compositional diversification of the volcanic suite. The preservation of such compositional melting effects, however, suggests that the most basic olivine-phyric basalts represent primitive magmas. The trace element characteristics of these magmas, and their derivatives, indicate that the mantle source for the Chukotat volcanics had experienced a previous melting event.  相似文献