Key site variables governing the functional characteristics of Dissolved Natural Organic Matter (DNOM) in Nordic forested catchments   总被引：1，自引：0，他引：1  

Rolf D. Vogt  Jarkko Akkanen  Dag Olav Andersen  Rainer Brüggemann  Bimal Chatterjee  Egil Gjessing  Jussi V. K. Kukkonen  Håkon E. Larsen  Jörg Luster  Andrea Paul  Stephan Pflugmacher  Mike Starr  Christian E. W. Steinberg  Philippe Schmitt-Kopplin  Ádám Zsolnay 《Aquatic Sciences - Research Across Boundaries》2004,66(2):195-210

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Guest Editorial - "Geoanalysis 2003"     

Jean S. Kane  Heikki Niskavaara  Lea Hmlinen  Harry Sandstrom  Michael H. Ramsey 《Geostandards and Geoanalytical Research》2004,28(1):7-7

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How reliable are growth strata in interpreting short-term (10 s to 100 s ka) growth structures kinematics?     

Sébastien Castelltort  Stéphane Pochat  Jean Van den Driessche 《Comptes Rendus Geoscience》2004,336(2):151-158

High-frequency stratigraphic cycles (10 s to 100 s ka) often show, at a specific location, an alternation of ‘dynamic’ (proximal-energetic), and ‘non-dynamic’ (distal-pelagic) processes with time. When sedimentation is syn-deformation, these processes tend respectively to fill-up tectonically-induced topography or to drape it. As a consequence, growth strata are alternatively thickened and isopach across the growth structure. High-resolution kinematic studies of growth structures (folds and faults), which assume that sedimentation always fills up topographies (‘fill-to-the-top’ model), may therefore mistake sedimentary cyclicity for tectonic cyclicity. We address this problem with one example of growth anticline in the Spanish Pyrenees, and we discuss the fill-to-the-top model. To cite this article: S. Castelltort et al., C. R. Geoscience 336 (2004).  相似文献   

Les sillons plissés du Burundien supérieur dans la chaı̂ne Kibarienne d'Afrique centrale     

Michel Villeneuve  Jean Chorowicz 《Comptes Rendus Geoscience》2004,336(9):807-814

The Kibaran belt that extends all over the central Africa, from the Katanga to the southern Uganda, straddles the African great lakes area. The Kibaran stratigraphy is one of the most debated questions. Some geologists favoured two different systems: the Ruzizian system (1800–2000 Ma) and the Burundian or Kibaran system (1600–960 Ma). Some others favoured a single Burundian system with large areas granitised and metamorphosed during several Burundian tectonic events and with a lot of sedimentary fold belts of the Burundian age. Recent geological data and new remote sensing interpretations allow us to favour the second hypothesis but with a major disconformity within the Burundian system which is separating the Upper and the Lower Burundian. To cite this article: M. Villeneuve, J. Chorowicz, C. R. Geoscience 336 (2004).  相似文献   

Reply to the comment by A. Cherchi and R. Schroeder on an article by J. Guex, Eclogae geol. Helv. 94 (2001) 321–328.     

Jean Guex 《Eclogae Geologicae Helvetiae》2004,97(3):445

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华南陡山沱期古地理环境及"雪球地球"研究新进展   总被引：4，自引：1，他引：4  

孙知明杨振宇  裴军令Jean BESSE　Melina MACOUIN　Stuart GILDER　Magali ADER 《地质通报》2004,23(8):728-731

华南地块陡山沱组的古地磁和C同位素研究揭示了其形成于赤道附近的古地理环境。对冰期后的盖帽白云岩的C同位素研究表明，δ^13C从-5‰开始有缓慢升高的趋势，与世界上Marinoan冰期其他剖面的c同位素变化相一致。陡山沱期大气中CO2含量的升高可能与kodinia超大陆的裂解及火山活动等密切相关。  相似文献   

L'érosion des chaînes de montagnes : influence de la sédimentation de piedmont     

Julien Babault  Jean Van Den Driessche   《Comptes Rendus Geoscience》2005,337(16):1431

The applanation of mountain belts that results in peneplain is generally considered to be caused by the long-term activity of erosion. Peneplanation has been previously defined as the lowering of an elevated topography and the concomitant subduing of its relief. We propose a model following which piedmont sedimentation induces the base level rise, allowing applanation to develop at high elevation and resulting in an elevated ‘peneplain’. This model is illustrated by the morphological evolution of the southern flank of the Pyrenees during the Cainozoic. To cite this article: J. Babault, J. Van Den Driessche, C. R. Geoscience 337 (2005).  相似文献   

Ilmenite, magnetite, and peraluminous Mesoproterozoic anorogenic granites of Laurentia and Baltica   总被引：5，自引：0，他引：5  

J. Lawford Anderson  Jean Morrison 《Lithos》2005,80(1-4):45-60

Emplacement of 1.6 to 1.3 Ga Mesoproterozoic plutons in Baltica and Laurentia formed an immense belt of A-type granite batholiths that include (1) low-fO₂, ilmenite-series granite intrusions from the Baltic region to Wyoming, (2) high-fO₂, magnetite-series granite intrusions of the central to southwestern U.S., and (3) peraluminous, two-mica granite intrusions from Colorado to central Arizona. These mineralogic divisions are mirrored by substantial elemental and oxygen isotopic differences. The ilmenite-series granites, which often contain classic rapakivi textures, have the highest Fe/Mg ratios and are highest in LIL element enrichment. They also have the lowest whole-rock δ¹⁸O values at 5.7‰ to 7.7‰. The magnetite-series granites are less potassic, less LILE-enriched, and have higher whole-rock δ¹⁸O values, ranging from 7.6‰ to 10.8‰. Although they retain A-type characteristics, the peraluminous granites are the least LILE-enriched and have the lowest Fe/Mg ratios. They also have the highest whole-rock δ¹⁸O values ranging from 8.8‰ to 12.0‰. Feldspar, where strongly reddened, can exhibit elevated δ¹⁸O values, which is interpreted to indicate subsolidus exchange with surface-derived aqueous fluids. Quartz δ¹⁸O values are interpreted to generally retain their magmatic values. The transcontinental mineralogic, chemical, and oxygen isotopic variations are interpreted as indicative of broad changes in the composition of a lower crustal source, which is compatible with a reduced mantle-derived crustal source for the ilmenite-series granites and a more oxidized crustal source for the others, including a metasedimentary component in the source for the two-mica granite subprovince.

Widespread thermal metamorphism at 1.4 Ga is present throughout much of the magmatic province and is viewed as a consequence of this immense event. Compressional deformation associated with several western 1.4 Ga Laurentia granite batholiths, alternatively interpreted as the distal expressions of a presumed 1.4 Ga orogeny, have at least in part been shown to be localized on preexisting Paleoproterozoic zones of deformation. Thus, we do not find compelling evidence for a 1.4 Ga orogeny related to the formation of most of these granites. Renewed intrusions at 1.0–1.1 Ga between and immediately following phases of the Grenville orogeny indicate that situations leading to their formation need to be more broadly considered.

The origin of this red granite-forming event in Laurentia and Baltica is considered as part of a global magmatic event that was coeval with intrusion of massif anorthosites and associated charnockites. Most are viewed as anorogenic, but it is recognized that the same conditions leading to their formation may have occurred during extensional phases of orogens. The immense volumes of red granites produced are also essentially unique to the Mesoproterozoic and appear to be tied to the stabilization and eventual break up of supercontinents of both Paleoproterozoic and Mesoproterozoic age.  相似文献   

La branche orientale de l'arc de Chypre. Morphostructure d'une frontière de plaques d'après les résultats de la campagne BLAC (2003)     

Jean Benkhelil  Mazhar Bayerly  Stéphane Branchoux  Thierry Courp  Eliane Gonthier  Christian Hübscher  Agnès Maillard  Elias Tahchi 《Comptes Rendus Geoscience》2005,337(12):1075-1083

The eastern bend of the Cyprus Arc, at the transition between the submerged Mediterranean subduction and the onshore fault zones that underline the Eurasian, African and Arabic plates boundaries is a submarine feature undergoing a complex tectonic deformation. The BLAC marine geophysical survey helps to better assess the type of the deformation that affects the Messinian to Quaternary sediments along this plate boundary. The deformation, focussed between two tectonic corridors, displays compressive and transpressive features in the central part, becoming thrusting when moving westward in connection with the Cyprus accretionnary wedge. The northeastern end of this submarine range connects with the Latakia Ridge, which is, together with its continental extension, under a tensional tectonic regime. To cite this article: J. Benkhelil et al., C. R. Geoscience 337 (2005).  相似文献   

Sm–Nd isotopic compositions as a proxy for magmatic processes during the Neoproterozoic of the southern Brazilian shield     

Maria do Carmo P. Gastal  Jean Michel Lafon  Lo Afraneo Hartmann  Edinei Koester 《Journal of South American Earth Sciences》2005,18(3-4):255-276

Combined analyses of Nd isotopes from a wide range of Neoarchaean–Cretaceous igneous rocks provides a proxy to study magmatic processes and the evolution of the lithosphere. The main igneous associations include the Neoproterozoic granitoids from the southern Brazilian shield, which were formed during two tectonothermal events of the Brasiliano cycle: the São Gabriel accretionary orogeny (900–700 Ma) and the Dom Feliciano collisional orogeny (660–550 Ma). Rocks related to the formation of the São Gabriel arc (900–700 Ma) mainly have a depleted juvenile signature. For the Neoproterozoic collisional event, the petrogenetic discussion focuses on two old crustal segments and three types of mantle components. However, no depleted juvenile material was involved in the formation of the Dom Feliciano collisional belt (800–550 Ma), which implies an ensialic environment for the Dom Feliciano orogeny. In the western Neoproterozoic foreland, records of a Neoarchaean lower crust predominate, whereas a Paleoproterozoic crust does in the eastern Dom Feliciano belt. The western foreland includes two amalgamated geotectonic domains, the São Gabriel arc and Taquarembó block. In the collisional belt, the old crust was intensely reworked during the São Gabriel event. In addition to the Neoproterozoic subduction-processed subcontinental lithosphere (São Gariel arc), we recognize two old enriched mantle components, which also are identified in the Paleoproterozoic intraplate tholeiites from Uruguay and the Cretaceous potassic suites from eastern Paraguay. One end member displays the prominent influence of Trans-Amazonian (2.3–2.0 Ga) or older subduction events, whereas the other can be interpreted as a reenrichment of the first during the latest Trans-Amazonian collisional or younger events. This reenriched mantle is documented in late Neoproterozoic suites from the western foreland (605–550 Ma) and younger suites from the eastern collisional belt (600–580 Ma). The other enriched mantle component with an old subduction signature, however, appears only in older rocks of the collisional belt (800–600 Ma). The participation of the subduction-related Brasiliano mantle as an end member of binary mixing occurred in some early Neoproterozoic suites (605–580 Ma) from the western foreland, but the contribution of the Neoarchaean lower crust increased near the late igneous event (575–550 Ma).  相似文献