Journal articles: 'Complexe collisionnel'

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Boursier, C., B. Mandal, D. Babikov, and M. L. Dubernet. "New H2O–H2O collisional rate coefficients for cometary applications." Monthly Notices of the Royal Astronomical Society 498, no. 4 (September 8, 2020): 5489–97. http://dx.doi.org/10.1093/mnras/staa2713.

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ABSTRACT We re-introduce a semiclassical methodology based on theories developed for the determination of broadening coefficients. We show that this simple and extremely fast methodology provides results that are in good agreement with results obtained using the more sophisticate MQCT approach. This semiclassical methodology could be an alternative approach which allows to provide large sets of collisional data for very complex molecular systems. It saves time both on the determination of potential energy surfaces and on the collisional dynamical calculations. In addition, this paper provides more complete sets of rotational de-excitation cross-sections and rate coefficients of H2O perturbed by a thermal average of water molecules. Those data can be used in the radiative transfer modelling of cometary atmospheres.

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Abel, Martin, Lothar Frommhold, Xiaoping Li, and K. L. C. Hunt. "Comparison of the Calculated Collision-Induced Absorption Spectra by Dense Hydrogen-Helium, Deuterium-Helium, and Tritium-Helium Gas Mixtures." Journal of Atomic, Molecular, and Optical Physics 2011 (October 11, 2011): 1–3. http://dx.doi.org/10.1155/2011/470530.

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We have recently determined the induced dipole surface (IDS) and potential energy surface (PES) of collisional H2-He complexes. We have used these surfaces to compute the binary collision-induced absorption spectra of H2 molecules interacting with He atoms and of D2 molecules interacting with He atoms. Here we extend these calculations to the case of T2 molecules interacting with He atoms. Whereas the electronic structure of X2-He is virtually the same for all hydrogen isotopes X = H, D, or T, the collisional dynamics and molecular scattering wave functions are different for the different collisional pairs. We have calculated spectra up to a temperature of 9000 K and frequencies up to 20,000 cm−1. Here we compare the calculated collision-induced absorption spectra for the different hydrogen isotopes. While we have observed reasonable agreement between our calculations and laboratory measurements for the collisional H2-He and D2-He complexes, there are no laboratory measurements for T2-He collisional complexes, and one must rely on the fundamental theory, supported by the agreement between theory and experiment for the other isotopes.

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Shin, H. K. "Collisional energy flow in weakly bound complexes." Journal of Chemical Physics 87, no. 2 (July 15, 1987): 993–1000. http://dx.doi.org/10.1063/1.453254.

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Abel, Martin, and Lothar Frommhold. "Collision-induced spectra and current astronomical research." Canadian Journal of Physics 91, no. 11 (November 2013): 857–69. http://dx.doi.org/10.1139/cjp-2012-0532.

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Collision-induced spectra are the spectra of complexes of two or more atoms or molecules in a “fly-by” collisional encounter. Collision-induced absorption (CIA) has been observed in many dense gases and gas mixtures, in most cases at infrared frequencies in the form of quasi continua, and also in liquids and solids. CIA spectra of several binary complexes have been computed using modern quantum chemical methods, combined with molecular scattering theory, which couples the collisional complex to the radiation field as usual in other spectroscopic work. Binary collisional systems, such as H2 interacting with another H2 molecule, or with a helium or hydrogen atom, are first candidates for such computational work, owing to their small number of electrons and the astrophysical interest in such systems. The computed CIA spectra are found to be in close agreement with existing laboratory measurements of such spectra. Laboratory measurements exist at a limited selection of temperatures around 300 K and lower, but theory currently also provides CIA data for temperatures up to 9000 K and for higher frequencies (well into the visible), on a dense grid of temperatures and frequencies. For such calculations, detailed potential energy surfaces (PES) of the supermolecular complexes, along with the induced dipole surfaces (IDS), are needed so that the rotovibrational matrix elements of PES and IDS may be computed for the molecules involved, which may be highly rotovibrationally excited. Modern astronomical research needs opacity tables for analyses of the atmospheres of “cool” objects, such as cool white dwarfs, solar and extrasolar planets and their big moons, cool main sequence stars, and “first” stars, which are briefly described in a concluding section.

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MEDEIROS, SILVIA R., CRISTINA M. WIEDEMANN-LEONARDOS, and SIMON VRIEND. "Evidence of mingling between contrasting magmas in a deep plutonic environment: the example of Várzea Alegre, in the Ribeira Mobile Belt, Espírito Santo, Brazil." Anais da Academia Brasileira de Ciências 73, no. 1 (March 2001): 99–119. http://dx.doi.org/10.1590/s0001-37652001000100009.

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At the end of the geotectonic cycle that shaped the northern segment of the Ribeira Mobile Belt (Upper Proterozoic to Paleozoic age), a late to post-collisional set of plutonic complexes, consisting of a wide range of lithotypes, intruded all metamorphic units. The Várzea Alegre Intrusive Complex is a post-collisional complex. The younger intrusion consists of an inversely zoned multistage structure envolved by a large early emplaced ring of megaporphyritic charnoenderbitic rocks. The combination of field, petrographic and geochemical data reveals the presence of at least two different series of igneous rocks. The first originated from the partial melting of the mantle. This was previously enriched in incompatible elements, low and intermediate REE and some HFS-elements. A second enrichment in LREE and incompatible elements in this series was due to the mingling with a crustal granitic magma. This mingling process changed the composition of the original tholeiitic magma towards a medium-K calc-alkalic magma to produce a suite of basic to intermediate rock types. The granitic magma from the second high-K, calc-alkalic suite originated from the partial melting of the continental crust, but with strong influence of mantle-derived melts.

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Landreh, Michael, Idlir Liko, Povilas Uzdavinys, Mathieu Coincon, Jonathan T. S. Hopper, David Drew, and Carol V. Robinson. "Controlling release, unfolding and dissociation of membrane protein complexes in the gas phase through collisional cooling." Chemical Communications 51, no. 85 (2015): 15582–84. http://dx.doi.org/10.1039/c5cc07045g.

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Benesch, Justin L. P. "Collisional activation of protein complexes: Picking up the pieces." Journal of the American Society for Mass Spectrometry 20, no. 3 (March 2009): 341–48. http://dx.doi.org/10.1016/j.jasms.2008.11.014.

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Dimitrijević, Milan S., Vladimir A. Srećković, Alaa Abo Zalam, Nikolai N. Bezuglov, and Andrey N. Klyucharev. "Dynamic Instability of Rydberg Atomic Complexes." Atoms 7, no. 1 (February 8, 2019): 22. http://dx.doi.org/10.3390/atoms7010022.

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Atoms and molecules in highly excited (Rydberg) states have a number of unique characteristics due to the strong dependence of their properties on the values of principal quantum numbers. The paper discusses the results of an investigation of collisional Rydberg complexes specific features, resulting in the development of dynamic chaos and the accompanying diffusion autoionization processes. It is shown (experiment and theory) that, in subthermal low energies, the global chaotic regime that evolved in quasimolecular systems leads to significant changes in the Rydberg gases radiation/ionization kinetics. The effect of Förster resonance on the width of the fluorescence spectra and stochastic ionization processes in Rydberg systems is also discussed.

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Borysow, Aleksandra. "Pressure-Induced Molecular Absorption in Stellar Atmospheres." International Astronomical Union Colloquium 146 (1994): 209–22. http://dx.doi.org/10.1017/s0252921100021345.

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Pressure-induced absorption arises in complexes of two or more inert atoms or molecules, due to dipole moments induced during the collisional interaction. The term “pressure-induced” still prevails in the astrophysical literature, yet “collision-induced” absorption (CIA), or “interaction-induced” absorption seems more appropriate and is commonly used elsewhere. Ordinary absorption processes in the infrared arise from individual, polar molecules interacting with electromagnetic radiation. As a consequence, the intensity of the allowed lines increases linearly with density. CIA, on the other hand, is most striking in gases composed of nonpolar, infrared-inactive molecules. Induced spectral lines are observed at rovibrational frequencies which are dipole-forbidden in single (i.e. non-interacting) molecules. Dipole transitions may, however, beinducedin the interacting pair. The new symmetry of the electronic cloud of a collisional complex may be very different from those of the isolated molecules and thus commonly allows for a transient dipole, which then interacts with radiation. Collision-induced absorption increases quadratically in the low density limit, thus reflecting the two-body origin of the basic absorption process. At higher gas densities, ternary interactions become significant and cubic and higher-order contributions to the observable absorption are then commonly seen.

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Boomeri, Mohammad, Rahele Moradi, and Sasan Bagheri. "Petrology and origin of the Lar igneous complex of the Sistan suture zone, Iran." Geologos 26, no. 1 (April 1, 2020): 51–64. http://dx.doi.org/10.2478/logos-2020-0004.

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AbstractThe Oligocene Lar igneous complex is located in the Sistan suture zone of Iran, being emplaced in Paleocene to Eocene flysch-type rocks. This complex includes mainly intermediate K-rich volcanic (trachyte, latite and andesite) and plutonic (syenite and monzonite) rocks that belong to shoshonitic magma. The geochemical characteristics of the Lar igneous complex, such as an enrichment of LREE and LILE relative to HREE and HFSE, respectively, a negative anomaly of Ti, Ba and Nb and a positive anomaly of Rb and Th are similar to those of arc-type igneous rocks. Tectonic discrimination diagrams also show that rocks of the Lar igneous complex fall within the arc-related and post-collisional fields and K-enrichment of these rocks confirm the post-collisional setting. Based on geochemical features, the Lar igneous complex magma was derived from partial melting of a phlogopite-bearing, enriched and metasomatised lithospheric mantle source and the magma was affected by some evolutionary processes like fractional crystallisation and crustal contamination.

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Pert, G. J. "Models of laser plasma ablation. Part 4. Steadystate theory: collisional absorption flow." Journal of Plasma Physics 49, no. 2 (April 1993): 295–316. http://dx.doi.org/10.1017/s0022377800017001.

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The clarification of models of laser ablation by plasma heating is examined using a general dimensional argument and introducing a set of universal parameters. The regime of laser-plasma interaction in which collisional absorption and thermal conduction dominate is examined for spherical systems. Detailed scaling relations are derived for uninhibited and flux-limited thermal conduction. The complete set of regimes for steady spherical flow are examined, and it is found that the most important flows are thin collisional and thick local absorption.

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Bornschein, Russell E., and Brandon T. Ruotolo. "Ion mobility-mass spectrometry of charge-reduced protein complexes reveals general trends in the collisional ejection of compact subunits." Analyst 140, no. 20 (2015): 7020–29. http://dx.doi.org/10.1039/c5an01242b.

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Multiprotein complexes have been shown to play critical roles across a wide range of cellular functions, but most probes of protein quaternary structure are limited in their ability to analyze complex mixtures and polydisperse structures using small amounts of total protein.

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Hildebrand, Robert S., and Joseph B. Whalen. "The mid-Cretaceous Peninsular Ranges orogeny: a new slant on Cordilleran tectonics? II: northern United States and Canada." Canadian Journal of Earth Sciences 58, no. 8 (August 2021): 697–719. http://dx.doi.org/10.1139/cjes-2021-0006.

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The mid-Cretaceous Peninsular Ranges orogeny occurred in the North American Cordillera and affected rocks from Mexico to Alaska. It formed when a marine trough, open for ∼35 million years, closed by westerly subduction beneath a 140–100 Ma arc complex. In Part I, we described the features of the orogen in Mexico and California, west to east: back-arc trough, magmatic arc, 140–100 Ma seaway, post-collisional 99–84 Ma granodioritic–tonalitic plutons emplaced into the orogenic hinterland during exhumation, an east-vergent thrust belt, and farther east, a flexural foredeep. In western Nevada, where the Luning–Fencemaker thrust might be a mid-Cretaceous feature, arc and post-collisional plutons occur in proximity. The orogen continues through the Helena salient and Washington Cascades. In British Columbia, rocks of the 130–100 Ma Gambier arc lie west of the exhumed orogenic hinterland and 99–84 Ma post-collisional plutons to collectively indicate westerly subduction. East-dipping reverse faults near Harrison Lake, active from ∼100 Ma until ∼90 Ma, shed 99–84 Ma debris westward into the Nanaimo back-arc region. Within Insular Alaska, the Early Cretaceous Gravina basinal arc assemblage was deformed at 100 Ma and flanked to the east by a high-grade hinterland cut by post-collisional plutons. In mainland Alaska, the 100 Ma collision of Wrangellia and the Yukon–Tanana–Farewell composite terrane occurred above a southward-dipping subduction zone as shown by the 130–100 Ma Chisana arc sitting on Wrangellia and southward-dipping, northerly vergent thrusts in the Lower Cretaceous Kahiltna basin to the north. The outboard back-arc region was filled with post-collisional detritus of the McHugh complex.

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Fu, Dong, Timothy M. Kusky, Simon A. Wilde, Brian F. Windley, Ali Polat, Bo Huang, and Zhipeng Zhou. "Structural anatomy of the early Paleozoic Laohushan ophiolite and subduction complex: Implications for accretionary tectonics of the Proto-Tethyan North Qilian orogenic belt, northeastern Tibet." GSA Bulletin 132, no. 9-10 (March 10, 2020): 2175–201. http://dx.doi.org/10.1130/b35442.1.

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Abstract Recognition of accretionary tectonics in ancient orogenic collages is important for reconstructing the long-term subduction, accretion, and erosional history of fossil convergent margins, and for understanding crustal growth and supercontinent assembly. The North Qilian orogenic belt (NQOB), located between the Alxa block and the Central Qilian–Qaidam block in northeastern Tibet, is a typical Phanerozoic accretionary-to-collisional orogenic belt that represents the termination of the northern branch of the Proto-Tethys Ocean. It contains two subparallel ophiolitic belts, arcs, and subduction complexes; the ophiolitic rocks in the northern belt have generally been considered to have formed in a back-arc setting. However, the subduction-accretion-collision history, subduction polarity, and timing of closure of the back-arc ocean remain equivocal. To address these problems, we conducted detailed field, structural, and geochronological investigations of the Laohushan ophiolite–accretionary complex and related sedimentary rocks in the eastern NQOB. The Laohushan Complex is divisible into (1) a northern sedimentary forearc, and a supra-subduction zone-type ultramafic-mafic forearc (ca. 450 Ma) composed of serpentinized harzburgite, gabbro, basalt, and plagiogranite; and (2) a southern accretionary complex, which consists of relatively coherent basalt-chert-mudstone ocean plate stratigraphy that is structurally repeated many times, trench-fill turbidites, mélanges, and widespread thrust imbricates and duplexes, block-in-matrix and asymmetric structures. Kinematic analysis indicates that the accretionary complex underwent southward thrusting and shearing; coupled with the spatial architecture of the different tectonic units, which suggests northward subduction beneath the northern forearc on the southern margin of the Alxa block. Detrital zircon ages of forearc clastic sandstones, pelagic mudstones, trench-fill turbidites, and the matrix of mélanges, together with the zircon ages of igneous ophiolitic rocks and post-accretionary intrusions, indicate that the terminal accretion and tectonic stacking of the Laohushan subduction complex was between ca. 447 and 430 Ma. We propose a geodynamic model involving back-arc basin opening (ca. 517–449 Ma), intra-oceanic subduction-accretion (ca. 449–430 Ma), and final obduction of the northern forearc to account for the evolutionary processes of the North Qilian back-arc basin. The anatomy of the forearc ophiolite and structurally lower accretionary complex indicates the complicated origins and mechanism of emplacement of the ophiolitic rocks. Field-based reconstruction of accretionary complexes and upper plate ophiolites, together with provenance analysis of related sedimentary sequences, provide crucial constraints on the prolonged evolution of paleo-ocean basins and accretionary-to-collisional orogens.

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Sepahi, Ali, Hossein Shahbazi, Wolfgang Siebel, and Ahmad Ranin. "Geochronology of plutonic rocks from the Sanandaj-Sirjan zone, Iran and new zircon and titanite U-Th-Pb ages for granitoids from the Marivan pluton." Geochronometria 41, no. 3 (September 1, 2014): 207–15. http://dx.doi.org/10.2478/s13386-013-0156-z.

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Abstract The Sanandaj-Sirjan zone of Iran is a metamorphic belt consisting of rocks which were metamorphosed under different pressure and temperature conditions and intruded by various plutons ranging in composition from gabbro to granite. The majority of these granitoids formed along the ancient active continental margin of the Neo-Tethyan ocean at the southeastern edge of the central Iranian microplate. Geochronological data published in recent years indicate periodic plutonism lasting from Carboniferous through Mesozoic to late-Paleogene times (from ca. 300 to ca. 35 Ma) with climax activity during the mid- and late-Jurassic. The age constraints for plutonic complexes, such as Siah-Kouh, Kolah-Ghazi, Golpayegan (Muteh), Azna, Aligoodarz, Astaneh, Borujerd, Malayer (Samen), Alvand, Almogholagh, Ghorveh, Saqqez, Marivan, Naqadeh and Urumieh, clearly indicate the periodic nature of magmatism. Therefore, the Sanandaj-Sirjan zone preserves the record of magmatic activity of a complete orogenic cycle related to (1) Permocarboniferous(?) rifting of Gondwana and opening of the Neo-Tethyan ocean, (2) subduction of the oceanic crust, (3) continental collision and (4) post-collision/post-orogenic activities. The formation of the Marivan granitoids, northwestern Sanandaj-Sirjan zone, for which we present U-Pb zircon and titanite ages of ca. 38 Ma, can be related to the collisional and post-collisional stages of this orogenic cycle.

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Farinella, P., D. R. Davis, F. Marzari, and D. Vokrouhlický. "Collisional evolution of asteroids." International Astronomical Union Colloquium 173 (1999): 129–44. http://dx.doi.org/10.1017/s025292110003133x.

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AbstractWe review the evidence for, and the modelling work devoted to, the substantial collisional evolution which has generated the current asteroid population and continually injects asteroid fragments into dynamicalroutesthrough which they can reach near-Earth space and sometimes hit our planet. The main obstacles to further progress in this research field are theoretical (mainly related to the physics of high-velocity impacts), but better observational data (in particular on the small-size end of the asteroid population) would help. However, in the last decade new insights have been obtained on specific important issues, such as the total mass of the asteroids at the time when the accretion process was stopped (only moderately larger than the current one), the “demography” of asteroid families (how many/how old they are and how they evolve) and the way meteorites and near-Earth asteroids are delivered/transported by a complex mixture of collisional and dynamical mechanisms.

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Resimic-Saric, Kristina, Vladica Cvetkovic, and Kadosa Balogh. "Radiometric K/ag data as evidence of the geodynamic evolution of the Zdraljica ophiolitic complex, central Serbia." Annales g?ologiques de la Peninsule balkanique, no. 66 (2005): 73–79. http://dx.doi.org/10.2298/gabp0566073r.

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The study presents age data and petrologic characteristics of igneous rocks of the Zdraljica ophiolitic complex (ZOC), situated in central Serbia, 150 km south of Belgrade. The complex consists predominately of a MORB/VAB-like tholeutic suite, represented mostly by gabbros and diabases. The tholeiitic suite is intruded by calc-alkaline intermediate and acid magmas of a VA-affinity, which presumably formed in a pre-collisional setting. The whole complex is intruded by peraluminous granite magmas. The crystallization age of the calc-alkaline pre-collisional quartzdiorite is 168.4?6.7 Ma and it post-dates the formation of the here exposed ocean?ic crust. Geological evidence suggest that the emplacement of the complex occurred during the Upper Jurassic. With respect to their petrology and age, the Zdraljica ophiolitic rocks are similar to the south Apuseni Mts. ophiolites, situated to the north, and to the Kursumija and Guevgeli ophiolites, situated to the south. All these ophiolites probably formed as parts of a single Jurassic belt, which can be termed the eastern branch of the Vardar Zone.

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Mercer, Roger S., and Alex G. Harrison. "Fragmentation of alkoxide ions following collisional activation. An energy-resolved study." Canadian Journal of Chemistry 66, no. 11 (November 1, 1988): 2947–53. http://dx.doi.org/10.1139/v88-455.

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The collisionally activated dissociation reactions of the C2 to C5 alkoxide ions have been studied for collisons occurring at 8 keV kinetic energy and also over the range 5 to 100 eV kinetic energy. The alkoxide ions fragment by 1,2-elimination of H2 and/or an alkane. Thus, primary alkoxide ions fragment by elimination of H2 only, secondary alkoxide ions show elimination of H2 and alkane molecules, while tertiary alkoxide ions show elimination of alkanes only. In alkane elimination, loss of CH4 is much more facilie than loss of larger alkanes. For secondary alkoxide ions, where more than one elimination reaction occurs, the energy dependence of fragmentation has been explored over the collision energy range 5 to 100 eV. The results are interpreted in terms of a step-wise mechanism involving formation of an anion-carbonyl compound ion-dipole complex, followed by proton abstraction by the H− or alkyl anion leading to the final products. The relative importance of the reaction channels is determined by the relative stabilities of these ion-dipole complexes.

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Niu, Shuai, and Brandon T. Ruotolo. "Collisional unfolding of multiprotein complexes reveals cooperative stabilization upon ligand binding." Protein Science 24, no. 8 (May 27, 2015): 1272–81. http://dx.doi.org/10.1002/pro.2699.

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Will, A. Yvette, Arsenio Muñoz De La Peña, Thilivhali T. Ndou, and Isiah M. Warner. "Influence of Triethanolamine on Aqueous β-Cyclodextrin/Pyrene Complexes." Applied Spectroscopy 49, no. 4 (April 1995): 520–25. http://dx.doi.org/10.1366/0003702953964192.

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The influence of triethanolamine (TEA) on the aqueous β-CD/pyrene fluorescence is examined. Collisional quenching of pyrene by TEA is indicated by Stern-Volmer plots. However, a decrease in the quenching is observed in the presence of β-cyclodextrin, which indicates an effective protection of the included pyrene molecules against quenching from TEA. A decrease in the apparent formation constant of the β-CD/pyrene complex also occurs in the presence of TEA. This phenomenon is attributed to a combination of an increased bulk solvent hydrophobicity and a competitive equilibrium between pyrene and TEA for the β-CD cavity. The present study indicates that TEA is not co-included in the β-CD/pyrene complex.

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Elmadhoun, Bassam M., Manal A. Swairjo, and Frank J. Burczynski. "Fluorescent Fatty Acid Transfer from Bovine Serum Albumin to Phospholipid Vesicles: Collision or Diffusion Mediated Uptake." Journal of Pharmacy & Pharmaceutical Sciences 15, no. 3 (July 19, 2012): 420. http://dx.doi.org/10.18433/j3bc8w.

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Purpose: The extent of palmitate uptake by hepatocytes is dependent upon the surface charge of the extracellular binding protein. Specifically, hepatocyte uptake is greater when palmitate is bound to cationic binding proteins than when it is bound to anionic proteins. To further understand the role of protein surface charge on the uptake process of protein-bound ligands, we examined the rate of transfer of fluorescent anthroyloxy palmitic acid (AOPA) in the presence of anionic and cationic extracellular proteins to model membranes containing different surface charged groups. Method: AOPA transfer rate in the presence of bovine serum albumin (ALB; isoelectric point pI = 4.8-5.0) or modified ALB (ALBe; pI = 7.0-7.5) to negative, positive and neutral lipid vesicles was investigated using a fluorescence resonance energy transfer assay. Results: The rate of AOPA transfer from both proteins was decreased when ionic strength was increased; directly dependent on the concentration of acceptor lipid vesicles; and was affected by both the lipid membrane surface charge and protein-bound concentration. Conclusion: The data support the notion that AOPA transfer from binding proteins to lipid membranes occurred through two concomitant processes, aqueous diffusion of the unbound ligand (diffusion-mediated process) and a collisional interaction between the protein-ligand complex and acceptor membrane. The contribution of diffusional mediated transfer to the overall uptake process was determined to be 3 to 4 times less than the contribution of a collisional interaction. This study strengthened the hypothesis that charged amino acid residues on proteins are important for effective collisional interaction between protein-ligand complexes and cell membranes through which more free ligand could be supplied for the uptake process. This article is open to POST-PUBLICATION REVIEW. Registered readers (see “For Readers”) may comment by clicking on ABSTRACT on the issue’s contents page.

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Dempster, T. J., and B. J. Bluck. "The age and tectonic significance of the Bute amphibolite, Highland Border Complex, Scotland." Geological Magazine 128, no. 1 (January 1991): 77–80. http://dx.doi.org/10.1017/s0016756800018069.

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AbstractSm–Nd and K–Ar isotopic determinations on an amphibolite from the Highland Border Complex yield Cambrian ages. Collisional events which might have generated the amphibolite appear incompatible with the passive margin character of Laurentia at that time. A possible explanation is that the part of the Highland Border Complex containing the amphibolite and associated rock units was generated outside Laurentia.

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Faure, Alexandre, Eric Josselin, Laurent Wiesenfeld, and Cecilia Ceccarelli. "Collisional excitation of complex organic molecules." Proceedings of the International Astronomical Union 4, S251 (February 2008): 137–38. http://dx.doi.org/10.1017/s1743921308021376.

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AbstractA major difficulty in modelling the infrared and (sub)millimeter spectra of gas-phase complex organic molecules is the lack of state-to-state collisional rate coefficients. Accurate quantum or classical scattering calculations for large polyatomic species are indeed computationally highly challenging, particularly when both rotation and low frequency vibrations such as bending and torsional modes are involved. We briefly present here an approximate approach to estimate and/or extrapolate rotational and rovibrational rates for polyatomic molecules with many degrees of freedom.

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Stringer, Michael B., Dennis J. Underwood, John H. Bowie, John L. Holmes, Alexander A. Mommers, and Jan E. Szulejko. "Is the collision induced loss of ethene from the (M – H+)− ion of butyrophenone a γ-hydrogen rearrangement?" Canadian Journal of Chemistry 64, no. 4 (April 1, 1986): 764–68. http://dx.doi.org/10.1139/v86-123.

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The (M – H+)− ion of butyrophenone undergoes the following reactions on collisional activation: losses of CH3•, CH4, (C,H5•), C2H4, C3H7•, (CO + CH4), together with formation of C6H5− and C4H5O−. Labelling studies (13C and 2H) show that the losses of CH3•, C3H7• and the formation of C6H5− and C4H5O− are specific and occur without hydrogen scrambling. All other reactions involve prior or accompanying hydrogen rearrangement. In particular, the loss of C2H4 is very complex: it involves loss of ethyl carbon atoms, but all hydrogen atoms are involved via specific rearrangement reactions. The phenyl–alkyl H rearrangements which are noted for this process occur after collisional activation of the (M – H+)− ion.

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HEIJMEN, TINO G. A., ROBERT MOSZYNSKI, PAUL E. S. WORMER, and AD VAN DER AVOIRD. "Symmetry-adapted perturbation theory applied to interaction-induced properties of collisional complexes." Molecular Physics 89, no. 1 (September 1996): 81–110. http://dx.doi.org/10.1080/002689796174029.

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Nielsen, Anders Baardseth, Preben Hvelplund, and Steen Brøndsted Nielsen. "Ruthenium diimine complexes in unusual charge states formed in collisional electron transfer." International Journal of Mass Spectrometry 232, no. 1 (March 2004): 79–82. http://dx.doi.org/10.1016/j.ijms.2003.11.011.

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Velojic, Milos, Dejan Prelevic, and Rade Jelenkovic. "The origin of lead and sulphur in Tulare ore field, Lece magmatic complex, SE Serbia." Annales g?ologiques de la Peninsule balkanique 79, no. 2 (2018): 19–28. http://dx.doi.org/10.2298/gabp1802019v.

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Lece magmatic complex in SE Serbia, part of the Serbo-Macedonian Metallogenic Province, is one of the most promising zones for lead, zinc and precious metals for the country. This complex was formed as a result of the post-collisional magmatic activity that lasted from Oligocene to Miocene. This study brings new lead and sulphur isotope data with an aim to constrain the origin of mineralizing fluids and to estimate the temperature of their formation. Galena from the Bakrenjaca locality shows high 207Pb/204Pb values implying that the lead was dominantly derived from the upper continental crustal geochemical reservoir which was probably recycled within the mantle and erupted during Tertiary post-collisional magmatism. Sulfur isotope composition of galena, sphalerite and pyrite show overlapping ?34S values in the range between 0 and 3? indicating a mantle origin of sulphur. Sulfur isotopes were also used to estimate the temperature under which the minerals were deposited forming a complex of veins. The calculated temperature is around 350?C. Since this temperature is too high for epithermal deposits, it is probable that the associated minerals weren?t deposited in isotopic equilibrium and other methods should be conducted for more precise temperature evaluation.

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Hildebrand, Robert S., and Joseph B. Whalen. "The mid-Cretaceous Peninsular Ranges orogeny: a new slant on Cordilleran tectonics? I: Mexico to Nevada." Canadian Journal of Earth Sciences 58, no. 8 (August 2021): 670–96. http://dx.doi.org/10.1139/cjes-2020-0154.

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The Peninsular Ranges orogeny occurred during the mid-Cretaceous at ∼100 Ma and affected rocks from southern Mexico to Alaska. The event resulted from the closing of an Early Cretaceous marine arc trough, named the Bisbee–Arperos seaway in Mexico and Arizona, and the Cinko Lake arc trough in the Sierra Nevada. The trough was an ocean that formed after the Late Jurassic – Early Cretaceous Nevadan orogeny and associated post-collisional magmatism. It was open for ∼40 million years and closed by westward subduction. Here, we focus initially on the most complete cross section, located in southwestern Mexico, where a west-facing Albian carbonate platform, with subjacent siliciclastic rocks built on the western margin of North America, was pulled down into a trench at 100 Ma, buried in hemipelagic mud and Cenomanian flysch, then overthrust from the west by rocks of the 140–100 Ma Santiago Peak – Alisitos arc and its substrate, the Guerrero Superterrane, which collectively document westerly subduction. This tectonically thickened collision zone was exhumed and intruded by 99–84 Ma distinctive post-collisional tonalite–granodiorite plutonic complexes, all with Sr/Y > 20, Sm/Yb > 2.5, Nb/Y > 0.4, and La/Yb > 10. These geochemical features are typical of slab failure, not arc magmas. The post-collisional plutons, previously considered to represent arc flare-ups, were derived from melting of the descending slab following arc-continent collision. Remnants of the arc, basin, related east-vergent 100 Ma thrusts, flexural foredeep, and 99–84 Ma slab failure plutons are traced from the Peninsular Ranges, through the Mojave Desert to the Sierra Nevada where similar rocks, relations, and ages occur. Along the western, back-arc, side of the orogen after collision and slab break-off, but during exhumation, east-dipping reverse faults with >10 km of east-side up movement shed 100–85 Ma plutonic and other debris westward from the hinterland into troughs such as the Valle and Great Valley. We extend our synthesis northward, from west-central Nevada to Alaska, in Part II.

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Vrublevskii, Vassily, Igor Gertner, Richard Ernst, Andrey Izokh, and Andrey Vishnevskii. "The Overmaraat-Gol Alkaline Pluton in Northern Mongolia: U–Pb Age and Preliminary Implications for Magma Sources and Tectonic Setting." Minerals 9, no. 3 (March 10, 2019): 170. http://dx.doi.org/10.3390/min9030170.

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A new Wenlockian zircon U–Pb age (~426 Ma) of the Overmaraat-Gol nepheline syenite (foyaite, juvite) pluton in the SW Lake Hovsgol area (Northern Mongolia) prompts a long history of alkaline magmatism in the western Central Asian Orogenic Belt, exceeding the duration of the Devonian and Permian–Triassic events. The LILE and HFSE patterns of pluton samples analyzed by X-ray fluorescence (XRF) and inductively coupled plasma (ICP-MS) methods indicate intrusion in a complex tectonic setting during interaction of a mantle plume with accretionary-collisional complexes that previously formed on the active continental margin. As a result, the parent magma had a heterogeneous source with mixed mantle (PREMA and EM) and crustal components. This source composition is consistent with Nd–Sr isotope ratios of the Overmaraat-Gol alkaline rocks, from −0.1 to −1.2 εNd(t) and from ~0.706 to 0.707 87Sr/86Sr(t).

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Carruba, V., L. G. M. Ramos, and F. Spoto. "Spin clusters inside four young asteroid groups." Monthly Notices of the Royal Astronomical Society 493, no. 2 (February 13, 2020): 2556–67. http://dx.doi.org/10.1093/mnras/staa447.

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ABSTRACT Asteroid groups may either form because of collisions or because of spin induced fission. Recently it has been shown that young spin clusters tend to form more frequently in young collisional families than in older groups. Here, we study the occurrence of spin clusters inside four very recently identified asteroid groups: the (525) Adelaide, (2258) Viipuri, (6142) Tantawi, and (18429) (1994 AO1) groups. Using combinations of techniques based on backward numerical simulations, we identify four spin pairs among the family members. All groups have fractions of observed spin clusters well above 5 per cent, so confirming an observed trend for other young asteroid groups. The (2258) Viipuri and (18429) (1994 AO1) groups are compatible with an origin as a spin clusters themselves, and could be other occurrences of cascade spin clusters, as recently detected in other asteroid groups. Finally, the separation between collisional asteroid families and spin clusters in domains of dispersion of proper semimajor axis, σa, versus age seems to be more complex than previously thought. While spin clusters tend to be much more compact in proper elements than collisional families, there appears to be a transition region in σa where both the groups be found.

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Lash, Gary G. "Detrital modes of the Riding Island Graywacke, north-central Newfoundland: evidence for deposition in a collisional successor basin in the Dunnage Zone." Canadian Journal of Earth Sciences 31, no. 1 (January 1, 1994): 176–81. http://dx.doi.org/10.1139/e94-014.

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The Riding Island Graywacke (late Caradoc – Ashgill) crops out in Notre Dame Bay, north-central Newfoundland. Previous tectonic interpretations suggest that this succession of turbidites and hemipelagic mudstone accumulated in a basin adjacent to an active volcanic arc. The varied framework mineralogy of 29 Riding Island samples studied, however, records derivation from a complex source terrane composed of mafic and silicic volcanic rocks, sedimentary and metamorphic successions, and plutonic rocks. Assessment of the tectonic environment of deposition of the Riding Island Graywacke by use of popular sandstone provenance ternary diagrams yields ambiguous results. The mineralogy of the Riding Island samples reveals a change in tectonic scenario from one dominated by island-arc volcanism in pre-Caradoc time to a setting marked by tectonic shortening, transcurrent faulting, and terrane accretion near the end of the Ordovician. The complex composition of these sandstones and the fact that they accumulated after island-arc volcanism had ended argue for deposition in a collisional successor basin that formed during the early stages of mountain building along the proto-North American continental margin. This inferred Late Ordovician collisional successor basin may have also been the locus of deposition for other minera-logically complex late Caradoc – Ashgill units exposed in Notre Dame Bay, such as the Sansom Formation.

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ZENG, XIANG, BING TANG, LIANG WANG, PENG KONG, and YI TANG. "ENERGY EXCHANGE IN COLLISIONS BETWEEN TWO DISSIPATIVE OPTICAL BULLETS." Journal of Nonlinear Optical Physics & Materials 22, no. 02 (June 2013): 1350018. http://dx.doi.org/10.1142/s0218863513500185.

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By using the three-dimensional complex cubic-quintic Ginzburg-Landau equation, the energy transfer process is investigated numerically for collisions of two dissipative optical bullets in a dissipative system. For high energy solitons, as a result of energy transfer, one soliton gains energy to generate a double bullet complex, and the other one loses energy can survive in collisional process. In addition, we find that the variations of the bullets velocity show regular properties during mutiple collisions with phase difference.

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Wasowicz, Tomasz J., Marta Łabuda, and Boguslaw Pranszke. "Charge Transfer, Complexes Formation and Furan Fragmentation Induced by Collisions with Low-Energy Helium Cations." International Journal of Molecular Sciences 20, no. 23 (November 29, 2019): 6022. http://dx.doi.org/10.3390/ijms20236022.

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The present work focuses on unraveling the collisional processes leading to the fragmentation of the gas-phase furan molecules under the He+ and He2+ cations impact in the energy range 5–2000 eV. The presence of different mechanisms was identified by the analysis of the optical fragmentation spectra measured using the collision-induced emission spectroscopy (CIES) in conjunction with the ab initio calculations. The measurements of the fragmentation spectra of furan were performed at the different kinetic energies of both cations. In consequence, several excited products were identified by their luminescence. Among them, the emission of helium atoms excited to the 1s4d 1D2, 3D1,2,3 states was recorded. The structure of the furan molecule lacks an He atom. Therefore, observation of its emission lines is spectroscopic evidence of an impact reaction occurring via relocation of the electronic charge between interacting entities. Moreover, the recorded spectra revealed significant variations of relative band intensities of the products along with the change of the projectile charge and its velocity. In particular, at lower velocities of He+, the relative cross-sections of dissociation products have prominent resonance-like maxima. In order to elucidate the experimental results, the calculations have been performed by using a high level of quantum chemistry methods. The calculations showed that in both impact systems two collisional processes preceded fragmentation. The first one is an electron transfer from furan molecules to cations that leads to the neutralization and further excitation of the cations. The second mechanism starts from the formation of the He−C4H4O+/2+ temporary clusters before decomposition, and it is responsible for the appearance of the narrow resonances in the relative cross-section curves.

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Likhanov, I. I., V. V. Reverdatto, and A. V. Travin. "Exhumation rate of rocks from Neoproterozoic collisional metamorphic complexes of the Yenisei Ridge." Doklady Earth Sciences 435, no. 1 (November 2010): 1518–23. http://dx.doi.org/10.1134/s1028334x10110243.

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35

Mesquita, Raissa Beloti de, Hanna Jordt-Evangelista, Gláucia Nascimento Queiroga, Edgar Batista de Medeiros Júnior, and Ivo Antônio Dussin. "Petrogenesis and age of skarns associated with felsic and metamafic dykes from the Paraíba do Sul Complex, southern Espírito Santo State." Brazilian Journal of Geology 47, no. 2 (April 2017): 301–25. http://dx.doi.org/10.1590/2317-4889201720160086.

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ABSTRACT: This paper concerns the study of petrography, mineral chemistry and geochronology of skarns generated at the contact of marbles of the Paraíba do Sul Complex with felsic and metamafic dykes in the southern Espírito Santo State. The marbles were metamorphosed under P-T granulite facies conditions during the syn-collisional stage of the Neoproterozoic Araçuaí orogen. Metamafic bodies are composed of amphibolite and hornblende granofels, while felsic dykes consist of alkali-feldspar granite, monzogranite or syenogranite. From marble towards the dyke, skarns related to the metamafic bodies are composed of carbonate + olivine and diopside + hornblende zones. Skarn associated to the granitic dykes are composed of three different zones: carbonate + tremolite, diopside, scapolite + diopside. Variations in mineral chemical compositions along the metasomatic zones suggest introduction of Mg and Ca from the marbles, Fe from the metamafic dykes and Na from the granitoids. The presence of spinel in the metamafic dykes and their skarns indicates that both were metamorphosed under granulite facies conditions during the 580-560 Ma syn-collisional stage. U-Pb zircon geochronology (LA-ICP-MS) of an alkali-feldspar granite dyke resulted in a crystallization age of ca.540 Ma, which suggests that its skarns are therefore younger than skarns associated with the syn-collisional metamafic dykes.

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Ndaw, D., C. T. Bop, G. Dieye, N. A. Boye Faye, and F. Lique. "The excitation of CNCN in the interstellar medium: hyperfine resolved rate coefficients and non-LTE modelling." Monthly Notices of the Royal Astronomical Society 503, no. 4 (March 18, 2021): 5976–83. http://dx.doi.org/10.1093/mnras/stab775.

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ABSTRACT The recent detections of CNCN and HNCCN+ are seen as further evidence of the large abundance of NCCN in the interstellar medium. The accurate determination of the abundance of these chemically related compounds from the observational spectra requires the prior calculation of collisional rate coefficients. In this work, we aimed at computing hyperfine resolved rate coefficients for the CNCN–He collisional system. First, we determined a new potential energy surface for the CNCN–He van der Waals complex from which we computed rotationally resolved excitation cross-sections for energies up to 800 cm−1 using the quantum mechanical close-coupling approach. Then, hyperfine resolved transitions between the 30 low-lying pure rotational levels of CNCN were computed for temperatures ranging from 5 to 150 K using an improved infinite order sudden approach. The analysis of the scattering results showed a propensity rule in favour of Δj = ΔF1 = ΔF for the hyperfine transitions and a slight dominance of the odd Δj transitions. Using these data, we carried out non-LTE radiative transfer calculations to simulate the excitation of CNCN in molecular clouds and to constrain the physical conditions of cold dark clouds. Preliminary results showed that the abundance of CNCN derived from observational spectra has to be revisited using these new collisional data.

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Gu, M. F. "The flexible atomic code." Canadian Journal of Physics 86, no. 5 (May 1, 2008): 675–89. http://dx.doi.org/10.1139/p07-197.

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We describe a complete software package for the computation of various atomic data such as energy levels; radiative transition; collisional excitation; ionization by electron impact, photoionization, autoionization; and their inverse processes radiative recombination and dielectronic capture. The atomic theoretical background and numerical techniques associated with each process are discussed in detail. Sample applications and results are presented. PACS Nos.: 31.15.–p, 32.70.Cs, 34.80.Kw, 32.80.Fb, 32.80.Dz

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38

Dell'Orco, Daniele, and Karl-Wilhelm Koch. "A dynamic scaffolding mechanism for rhodopsin and transducin interaction in vertebrate vision." Biochemical Journal 440, no. 2 (November 14, 2011): 263–71. http://dx.doi.org/10.1042/bj20110871.

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The early steps in vertebrate vision require fast interactions between Rh (rhodopsin) and Gt (transducin), which are classically described by a collisional coupling mechanism driven by the free diffusion of monomeric proteins on the disc membranes of rod and cone cells. Recent findings, however, point to a very low mobility for Rh and support a substantially different supramolecular organization. Moreover, Rh–Gt interactions seem to possibly occur even prior to light stimuli, which is also difficult to reconcile with the classical scenario. We investigated the kinetics of interaction between native Rh and Gt in different conditions by surface plasmon resonance and analysed the results in the general physiological context by employing a holistic systems modelling approach. The results from the present study point to a mechanism that is intermediate between pure collisional coupling and physical scaffolding. Such a ‘dynamic scaffolding’, in which prevalently dimeric Rh and Gt interact in the dark by forming transient complexes (~25% of Gt is precoupled to Rh), does not slow down the phototransduction cascade, but is compatible with the observed photoresponses on a broad scale of light stimuli. We conclude that Rh molecules and Rh–Gt complexes can both absorb photons and trigger the visual cascade.

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Vladimirov, A. G., A. V. Travin, Phan Luu Anh, N. G. Murzintsev, and E. I. Mikheev. "Thermochronology of cordilleran metamorphic core complexes: example of Song Chay massif in Northern Vietnam." Доклады Академии наук 488, no. 6 (October 30, 2019): 630–39. http://dx.doi.org/10.31857/s0869-56524886630-639.

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Based on the reconstruction of the thermal evolution of the Song-Chai granitoid massif (Northern Vietnam) the long-term existence of granitoid magma at deep levels of the Earths crust (H = 15-20 km, t ~ 20-50 Ma) is established. Geodynamic analysis and mathematical modeling of thermal history of the granitoid batholith cooling shows that the magmatic chamber should be considered as thermal trap on the lower level of the earths crust, preserving residual granite melts for a long time. Activation of the magmatic chamber occurs in post-collisional strike-slip tectonics zones and is associated by tectonic exhumation of large segments of the earths crust. Ultimately, this leads to the transformation of the batholith into Cordilleran type metamorphic core complexes, emplacement of residual rare-metal melts and the formation of commercial deposits.

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40

Lenaz, Giorgio. "Lipid fluidity and membrane protein dynamics." Bioscience Reports 7, no. 11 (November 1, 1987): 823–37. http://dx.doi.org/10.1007/bf01119473.

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Membrane fluidity plays an important role in cellular functions. Membrane proteins are mobile in the lipid fluid environment; lateral diffusion of membrane proteins is slower than expected by theory, due to both the effect of protein crowding in the membrane and to constraints from the aqueous matrix. A major aspect of diffusion is in macromolecular associations: reduction of dimensionality for membrane diffusion facilitates collisional encounters, as those concerned with receptor-mediated signal transduction and with electron transfer chains. In mitochondrial electron transfer, diffusional control is prevented by the excess of collisional encounters between fast-diffusing ubiquinone and the respiratory complexes. Another aspect of dynamics of membrane proteins is their conformational flexibility. Lipids may induce the optimal conformation for catalytic activity. Breaks in Arrhenius plots of membrane-bound enzymes may be related to lipid fluidity: the break could occur when a limiting viscosity is reached for catalytic activity. Viscosity can affect protein conformational changes by inhibiting thermal fluctuations to the inner core of the protein molecule.

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41

Park, Jeong-Yeong, Seung-Ik Park, and Taejin Choi. "Microstructural and Geochronological Analyses of Mesozoic Ductile Shear Zones in the Western Gyeonggi Massif, Korea: Implications for an Orogenic Cycle in the East Asian Continental Margin." Minerals 10, no. 4 (April 17, 2020): 362. http://dx.doi.org/10.3390/min10040362.

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In response to orogenic cycles, the ductile shear zone records a complex crustal deformation history. In this study, we conducted a microstructural analysis of two NW–SE trending ductile shear zones (Deokjeok Shear Zone (DSZ) and Soya Shear Zone (SSZ)) in the Late Triassic post-collisional granites along the western Gyeonggi Massif in the Korean Peninsula. The DSZ, overlain by the Late Triassic to the Early Jurassic post-collisional basin fill (Deokjeok Formation), has asymmetric microstructures indicative of a top-down-to-the-northeast shear. Depending on the structural position, the SSZ, which structurally overlies the Deokjeok Formation, exhibits two contrasting styles of deformation. The lower portion of the SSZ preserves evidence of top-up-to-the-southwest shearing after top-down-to-the-northeast shearing; on the other hand, the upper portion only indicates a top-up movement. Given the primary deformation mechanisms of both quartz and feldspar, the deformation temperatures of DSZ and SSZ were estimated at ~300–350 °C and ~350–400 °C, respectively, indicative of the mid-crustal condition. New zircon U-Pb isotopic ages from mylonitic granite in the SSZ and volcanic rocks in the Deokjeok Formation, combined with previously published geochronological data, indicate that the post-collisional granites and volcano-sedimentary sequence were nearly contemporaneous (ca. 223–217 Ma) and juxtaposed because of the Late Triassic orogenic collapse and subsequent new orogenic event. In this study, we highlight the role of the extensional DSZ as a detachment propagated into the middle crust during the Late Triassic orogenic collapse. Our results report a deformational response to a transition from the collisional Songrim Orogeny to the subduction-related Daebo Orogeny in the western Gyeonggi Massif. This, in turn, provides essential insight into cyclic mountain building/collapse in the East Asian continental margin during the Mesozoic time.

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42

Gonzalez-Ondina, Jose M., Luigi Fraccarollo, and Philip L. F. Liu. "Two-level, two-phase model for intense, turbulent sediment transport." Journal of Fluid Mechanics 839 (January 26, 2018): 198–238. http://dx.doi.org/10.1017/jfm.2017.920.

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The study of sediment transport requires in-depth investigation of the complex effects of sediment particles in fluid turbulence. In this paper we focus on intense sediment transport flows. None of the existing two-phase models in the literature properly replicates the liquid and solid stresses in the near bed region of high concentration of sediment. The reason for this shortcoming is that the physical processes occurring at the length scale of the particle collisions are different from those occurring at larger length scales and therefore, they must be modelled independently. We present here a two-level theoretical derivation of two-phase, Favre averaged Navier–Stokes equations (FANS). This approach treats two levels of energy fluctuations independently, those associated with a granular spatial scale (granular temperature and small-scale fluid turbulence) and those associated with the ensemble average (turbulent kinetic energy for the two phases). Although similar attempts have been made by other researchers, the two level approach ensures that the two relevant length scales are included independently in a more consistent manner. The model is endowed with a semi-empirical formulation for the granular scale fluid turbulence, which is important even in the dense collisional shear layer, as has been recently recognized. As a result of the large and small scale modelling of the liquid and solid fluctuations, predictions are promising to be reliable in a wide range of flow conditions, from collisional to turbulent suspensions. This model has been validated for steady state flows with intense, collisional or mixed collisional–turbulent sediment transport, using various sources of detailed experimental data. It compares well with the experimental results in the whole experimental range of Shields parameters, better than previous models, although at the cost of increased complexity in the equations. Further experiments on turbulent suspensions would be necessary to definitely assess the model capabilities.

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Grannik, V. M. "Igneous rocks of accretionary and accretionary-collisional complexes of the Tonin-Aniva Peninsula (Sakhalin)." Doklady Earth Sciences 447, no. 2 (December 2012): 1297–300. http://dx.doi.org/10.1134/s1028334x12110086.

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Maffucci, Dominique M., Hua Guo, Nicholas S. Shuman, Shaun G. Ard, Albert A. Viggiano, and Juergen Troe. "Collisional stabilization of ion-molecule association complexes in He, H2, or N2 buffer gases." International Journal of Mass Spectrometry 460 (February 2021): 116494. http://dx.doi.org/10.1016/j.ijms.2020.116494.

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45

Brunetti, Brunetto, Stefano Falcinelli, Andrea Sassara, Jaime de Andres, and Franco Vecchiocattivi. "Auto-ionization of the collisional complexes of metastable neon and H2, D2, or HD." Chemical Physics 209, no. 2-3 (September 1996): 205–16. http://dx.doi.org/10.1016/0301-0104(96)00096-1.

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46

Guillot, François, Olivier Averbuch, Michel Dubois, Cyril Durand, Pierre Lanari, and Arnaud Gauthier. "Zircon age of vaugnerite intrusives from the Central and Southern Vosges crystalline massif (E France): contribution to the geodynamics of the European Variscan belt." BSGF - Earth Sciences Bulletin 191 (2020): 26. http://dx.doi.org/10.1051/bsgf/2020027.

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To provide a better picture of the active geodynamics along the Variscan suture zones during the late collisional stage (particularly regarding the evolution of the orogenic system towards HT conditions), we focused here on vaugnerites, which consist of mafic ultra-potassic magmatic rocks, intrusive into the granite-gneiss sequences of the Variscan Vosges crystalline massif. Those rocks, though subordinate in volume, are frequently associated with late-collisional granites. In the Central-Southern Vosges, they appear either as (1) pluton margin of the Southern Vosges Ballons granite complex or (2) composite dykes intrusive into migmatite and metamorphic sequences classically referred to as granite-gneiss unit (Central Vosges). Both types correspond to melanocratic rocks with prominent, Mg-rich, biotite and hornblende (20–40% vol., 64 < mg# < 78), two-feldspar and quartz. Those Vosges vaugnerites display geochemical signatures characteristic of ultra-potassic mafic to intermediate, metaluminous to slightly peraluminous rocks. Zircon U-Pb ages were obtained by Laser Ablation Inductively Coupled Plasma Mass Spectrometry. Zircon grains were extracted from a sillimanite-bearing gneiss from the granite-gneiss unit hosting the Central Vosges vaugnerites. They yielded an age at 451 ± 9 Ma, indicating a pre-Variscan Upper Ordovician protolith for the host sequence. Zircon from the four vaugnerite intrusives display U-Pb ages (± 2σ) of 340 ± 2.5 Ma (Ballons), 340 ± 25 Ma, 340 ± 7 Ma and 336 ± 10 Ma (Central Vosges). Synchronous within uncertainty, vaugnerite age data suggest a relatively early emplacement during the Late Variscan collisional history (i.e. Middle Visean times). These results are in line with previously published ages from the Southern Vosges volcano-sedimentary sequences (Oderen-Markstein) and the nearby ultra-potassic granite complexes from the Central and Southern Vosges (Ballons, Crêtes) thereby arguing for a magmatic event of regional significance. Recent petrological studies on vaugnerites suggest that they derive from partial melting of a metasomatized mantle contaminated to some different degrees by elements of continental crust. We propose here that the major ultra-potassic magmatic pulse at 340–335 Ma is a consequence of a significant change into the dynamics of the Rhenohercynian subduction system below the Central-Southern Vosges. In the light of recent thermo-mechanical modelling experiments on mature continental collision, magmatism could result from a syn-collisional lithospheric delamination mechanism involving (1) first, continental subduction evolving towards (2) the underthrusting of the Avalonian continental margin lower crust and (3) the initiation of lithospheric delamination within the supra-subduction retro-wedge (Saxothuringian-Moldanubian continental block). This delamination would drive the emplacement of an asthenospheric upwelling, initially localized along the Variscan suture zones, and gradually propagating towards the southern front of the belt during the Late Carboniferous, as the delamination front migrated at the base of the crust.

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Katkov, S. M. "The features of the Paleozoic-Mesozoic complexes of Kiber Cape (Chukotka, Arctic Russia): a structural-deforma-tion analysis." Proceedings of higher educational establishments. Geology and Exploration, no. 1 (February 28, 2017): 16–21. http://dx.doi.org/10.32454/0016-7762-2017-1-16-21.

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Three major regional deformation stages of Central Chukotka tectonic evolution were determined in Paleozoic-Mesozoic deposits of Kiber Cape. The research was based on a structural analysis of the linear and planar elements. Ellesmerian (Late Devonian) structural parageneses were masked during (at least) two phases of young Mesozoic-Cenozoic deformations: syncollisional North-North-East - South-South-West and North-West - South-East regional compressions and post-collisional extension of various directions, followed the compressions. The structural data comparison was made for Kiber Cape region, South-Anyui suture and Western Chukotka sector. It was emphasized that these regional units have similar structure styles and coeval phases of the tectonic transformations.

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Oellerich, Silke, Daniel Berg, Karlheinz Maier, and Frank Terjung. "Influence of Molecular Oxygen on the Chlorophyll Fluorescence Decay of Green Algae." Zeitschrift für Naturforschung C 54, no. 5-6 (June 1, 1999): 348–52. http://dx.doi.org/10.1515/znc-1999-5-609.

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Abstract Chlorella vulgaris, Chlorophyll Fluorescence Quenching, Green Algae, Molecular Oxygen Molecular oxygen can act as a collisional quencher of the singlet excited state of chlorophyll a. This effect is well described for chlorophyll a in various solvents but not for chlorophyll a in the antenna complexes of photosynthetic organisms. We studied the chlorophyll fluorescence decay of Chlorella vulgaris cells under different oxygen concentrations but did not find any evidence for quenching by oxygen.

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MATHIAUD, JULIEN. "LOCAL SMOOTH SOLUTIONS OF A THIN SPRAY MODEL WITH COLLISIONS." Mathematical Models and Methods in Applied Sciences 20, no. 02 (February 2010): 191–221. http://dx.doi.org/10.1142/s0218202510004192.

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Sprays are complex flows made of liquid droplets surrounded by a gas. The aim of this paper is to study the local in time well-posedness of a collisional thin spray model, that is a coupling between Euler equations for a perfect gas and a Vlasov–Boltzmann equation for the droplets. We prove the existence and uniqueness of (local in time) solutions for this problem as soon as initial data are smooth enough.

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Slabunov, A. I., V. V. Balagansky, and A. A. Shchipansky. "Mesoarchean to Paleoproterozoic Crustal Evolution of the Belomorian Province, Fennoscandian Shield, and the Tectonic Setting of Eclogites." Russian Geology and Geophysics 62, no. 5 (May 1, 2021): 525–46. http://dx.doi.org/10.2113/rgg20204266.

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Abstract —The Belomorian Province (BP) of the Fennoscandian Shield is a high-grade belt composed of Meso- to Neoarchean tonalite– trondhjemite–granodiorite (TTG) gneisses with subordinate supracrustal complexes. The Belomorian crust is underlined by a thick mantle keel, a structural element typical of Archean cratons. Belomorian rocks were metamorphosed under conditions of mainly high-pressure amphibolite to granulite facies in both Archean and Paleoproterozoic times. The TTG gneisses contain numerous blocks of almost completely retrogressed eclogite (eclogite-1). This paragenetic association of eclogite-1 and gneisses can be classified as an Archean eclogite–TTG gneiss mélange, a component of the Belomorian continental crust produced by subductional, accretionary, and collisional processes of the Belomorian collisional orogeny 2.9–2.66 Ga. The Paleoproterozoic history of the BP comprises of two prominent tectonic periods: (i) early Paleoproterozoic (~2.5–2.4 Ga), related to a superplume, and (ii) late Paleoproterozoic (2.0–1.85 Ga), resulted from crustal reworking during the Lapland–Kola collisional orogeny that produced strong penetrative metamorphic and local deformational overprint. The Paleoproterozoic highest-grade metamorphic overprint is represented by patches of eclogites (eclogite-2) in Paleoproterozoic mafic dikes and eclogite-1. Field relations between eclogite-1 and eclogite-2 are described in the Gridino area of the western coast of the White Sea. So, the BP is a high-grade polymetamorphic belt formed by a superposition of the Neoarchean Belomorian and Paleoproterozoic Lapland–Kola orogenies, whose characteristic features are eclogites produced by subduction and collision.

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Journal articles on the topic 'Complexe collisionnel'

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