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14. Ganges basin geometry records a pre-15 Ma isostatic rebound of Himalaya

Author

Mugnier, Jean-Louis and Huyghe, Pascale

Subjects
Himalaya Mountains -- Research, Geology -- Research, Tectonics (Geology) -- Research, Earth sciences
Abstract

The Tertiary continental strata of the Himalayan foreland basin are subdivided into two groups, but the meaning of this subdivision was previously unclear. From the analysis of drill holes, seismic lines, dated sections, outcrops, and balanced cross sections, we find that the southward migration rate of the depositional pinch-out of the younger group is 19 [+ 0r -] 5 mm/yr and equals the Himalayan shortening rate. This equality shows that the flexural foreland basin development is mainly controlled by the motion of the thrust load. The long-term pinch-out migration rate was slower for the older synorogenic group. Erosion locally occurred at the end of its deposition, due to tectonic reactivation of lineaments of the Indian shield. We suggest that this change in the basin development is linked to the detachment of the subducted Indian lithosphere that decreased the slab pull and increased the mean compressive stress within the Indian plate, whereas the plate motion remained constant. The most important implication of our work is that the associated isostatic rebound could have increased the Himalayan elevation prior to 15 Ma. Keywords: Himalaya, flexure, foreland basin, relief, slab break-off, tectonic reactivation.

Published
2006

15. Channel profiles through the active thrust front of the southern Barbados prism

Author

Huyghe, Pascale, Foata, Michel, Deville, Eric, and Mascle, Georges

Subjects
Geology -- Research, Earth sciences
Abstract

Submarine channels of the Orinoco River were analyzed using high-quality, dense-coverage bathymetric and seismic data provided by a recent marine survey on the southern Barbados prism. Analysis of the syntectonic sediments on seismic profiles shows that the four to five frontmost structures show evidence of recent tectonic movement. Slope analysis of the major channels was performed. From their headwaters to domains of little or no active tectonics, the channels display Keywords: channel slope, submarine canyon, active tectonics, southern Barbados prism.

Published
2004

17. Propagation of the thrust system and erosion in the Lesser Himalaya: geochemical and sedimentological evidence

Author

Huyghe, Pascale, Galy, Albert, Mugnier, Jean-Louis, and France-Lanord, Christian

Subjects
Himalaya Mountains -- Natural history, Nepal -- Natural history, Geological research -- Reports, Thrust faults (Geology) -- Research, Mountains -- Natural history, Geochemistry -- Usage, Earth sciences
Abstract

Sedimentological and Nd isotope data of two sections of the sub-Himalaya of western Nepal are used as new constraints for understanding the erosion history of the Himalaya. Throughout the deposition of the middle and upper members of the Siwalik Group, the Lesser Himalaya contribution to the total detrital input progressively increased from less than 20% to 40%. The increasing proportion of Lesser Himalaya sediments started at ca. 10-8 Ma and is associated with a coarsening of the maximum grain size at both microscopic and macroscopic scales. Thin-skinned tectonics of the Lesser Himalaya thrust system would have controlled the exhumation of the Lesser Himalaya rocks and would have begun at 12-10 Ma, taking into account the delay for denudation. Together with other studies, these data restrict the onset of movement on the Lesser Himalaya thrust system to less than 3 m.y. along more than 1750 km. This short time frame implies a ratio of lateral propagation rate to shortening rate far too high for the propagation of a single crustal thrust; thus we suggest instead the simultaneous initiation of several thrusts ahead of the Main Central thrust at ca. 12 Ma. We suggest that a rapid rise of the Tibetan Plateau at this time has transformed the Himalaya to an overcritical thrust wedge that has propagated forward to return to a stable state. This regional rising could be the prime cause of the increase of sediment influx at ca. 11 Ma around the Himalaya. Keywords: Siwalik formations, neodymium, grain size, erosion, thrust sheets, Himalaya.

Published
2001

21. Neogene Himalayan erosion regime and climate recorded in the Bengal Fan at 8 • N (IODP Exp. 354)

Author

France-Lanord, Christian, Galy, Albert, Huyghe, Pascale, Rigaudier, Thomas, Centre de Recherches Pétrographiques et Géochimiques (CRPG), Institut national des sciences de l'Univers (INSU - CNRS)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Institut des Sciences de la Terre (ISTerre), Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), France-Lanord, Christian, and Université de Lorraine (UL)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[SDU] Sciences of the Universe [physics], [SDU]Sciences of the Universe [physics], [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry, [SDU.STU.GC] Sciences of the Universe [physics]/Earth Sciences/Geochemistry, [SDU.STU] Sciences of the Universe [physics]/Earth Sciences, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences
Abstract

International audience; The Indian monsoon and tectonic both control the Himalayan erosion. Tectonic generates uplift and maintain high elevation of the range and earthquakes weaken the mountain front. Monsoon seasonal intensity controls the glacier cover, landslide activity, river incision, vegetation cover, and export of sediments towards the floodplain. The monsoon also exerts a primary control on the chemical erosion as weathering rates are clearly dependent upon river discharge. In the floodplain, sediment export is also tightly controlled by climate. The seasonality and intensity of the monsoon generate discharge high enough to ensure the efficiency of river transport of sand-rich sediments to the delta and shelf (Lupker et al. JGR, 2011). IODP Expedition 354 allowed to drill a series of seven sites along an E-W transect at 8 • N in the Bengal fan. This generated a comprehensive record of Himalayan erosion since 20 Ma. Bengal fan sediments are dominated by turbidites characterised by high accumulation rate and variable grain size raging from clayey silt to sand. Plio-Pleistocene turbidites reveal frequent channel levee deposition with massive sand deposition in inter-levee intervals. Overall, sand represents at least a third of the fan deposition. Turbidites are intercalated with hemipelagic sediments characterised by low accumulation rates, 20 to 50% of biogenic carbonates, fine grains and bioturbation. Turbidites have petrographic and geochemical signatures characteristic of sediments derived from the Himalaya such as the Ganga and Brahmaputra rivers that supply the fan (see A. Galy et al. this session). Major and trace element geochemistry show relatively stable compositions throughout the Neogene and Quaternary. They reveal a very weak regime of chemical weathering with no significant variation through time. Concentrations in mobile elements such as Na and K relative to Al are significantly higher than in modern river and northern fan sediments. This suggests that weathering and/or soil erosion are amplified in the modern time. Detrital carbonate concentration vary significantly with higher concentrations during the Miocene then falling during the Plio-Pleistocene. This suggests either a change in the exposition of Tethyan series in Himalaya or significantly lower chemical weathering during Miocene. Finally, clay composition is dominated by illite which also differs with the present Ganga which is rich in smectite. The record at 8 • N contrasts with the ODP Leg 116 record at 1 • S in the distal fan, which from 7 to 1 Ma shows a high degree of weathering associated to lower accumulation rates. The record at 8 • N indicates that these variations do not reflect changes in the continental source basin but rather reflect a change in the turbiditic export. The Bengal Fan record at 8 • N suggests that an erosion regime dominated by physical erosion able to drive large amount of sand and silt with low weathering was established at least 20 Ma ago and remained relatively stable in spite of the global climate variations. These observations suggest that erosion sustained by a highly seasonal climate able to ensure rapid transport of sediments such as the monsoon was already active 20 Ma ago.

Published
2019

22. Le transect IODP Exp. 354 à 8°N du Cône du Bengale et l'histoire de l'érosion de la Himalaya et de la mousson indienne au Néogène

Author

France-Lanord, Christian, Feakins, Sarah, Galy, Albert, Galy, Valier, Huyghe, Pascale, Lavé, Jérôme, Lénard, Sébastien, Rigaudier, Thomas, France-Lanord, Christian, Centre de Recherches Pétrographiques et Géochimiques (CRPG), Institut national des sciences de l'Univers (INSU - CNRS)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), University of Southern California (USC), Department of Marine Chemistry and Geochemistry (WHOI), Woods Hole Oceanographic Institution (WHOI), Institut des Sciences de la Terre (ISTerre), Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), and Université de Lorraine (UL)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[SDU.STU.TE]Sciences of the Universe [physics]/Earth Sciences/Tectonics, [SDU.STU.TE] Sciences of the Universe [physics]/Earth Sciences/Tectonics, [SDU.STU] Sciences of the Universe [physics]/Earth Sciences, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, [SDU.ENVI] Sciences of the Universe [physics]/Continental interfaces, environment
Abstract

International audience; En Himalaya, la mousson et la tectonique de convergence Inde-Asie contrôlent directement l'érosion. La tectonique engendre la haute élévation de la chaîne et les tremblements de terre qui fragilisent l'ensemble. L'intensité de la mousson contrôle la couverture glaciaire, les glissements de terrain, l'incision, la couverture végétale et l'export des sédiments vers la plaine. La mousson contrôle également l'intensité de l'érosion chimique. Dans la plaine, la saisonnalité et l'intensité de la mousson permettent d'atteindre des débits suffisamment élevés pour assurer l'efficacité du transport sédimentaire vers le delta. Ce transport rapide est également un facteur limitant de l'altération en réduisant le temps de séjour dans la plaine. Ces sédiments sont ensuite exportés vers la baie du Bengale ou ils alimentent le plus important système turbiditique de la planète. L'Expédition IODP 354 a foré le Cône du Bengale en 2015 et a restitué un enregistrement quasi continu de l'érosion de l'Himalaya au cours du Néogène et du Quaternaire (France-Lanord et al. 2016). Les sédiments sont principalement composés de turbidites issues du bassin du Gange-Brahmapoutre. L'Expedition 354 a foré un transect E-W de sept Sites sur 320 km à 8° N afin de couvrir autant que possible les déplacements de dépocentre. Le site le plus profond U1451, atteint la base du cône datant un début de sédimentation turbiditique vers 20 Ma sur le flanc de la ride Ninetyeast. Les sédiments présentent des analogies minéralogiques, géochimiques et isotopiques avec les sédiments modernes du Gange-Brahmapoutre. La variabilité interne révèle que les turbidites ne sont pas en permanence un mélange des deux fleuves. Au Quaternaire, il est évident que le Brahmapoutre était parfois la seule source de turbidites. La géochimie des éléments majeurs et des éléments traces montre des compositions relativement stables tout au long du Néogène et du Quaternaire. Ils révèlent un très faible régime d'altération sans variation significative dans le temps. Ces données comparées à celles des sédiments modernes du Gange et du Brahmapoutre impliquent que l'altération ou l'érosion des sols est amplifiée par la pression anthropique. Au plan paléoenvironnemental, les compositions isotopiques d'hydrogène et de carbone des cires foliaires datent l'expansion connue des plantes de type savane (C4) dans le bassin vers 6 Ma et montrent que depuis le Miocène les paléoprécipitations sont fortement appauvries en deutérium. Ce point implique que dès le Miocène, le régime de mousson indienne est établi, le Pléistocène étant marqué par une augmentation de la variabilité. Les paléoconcentrations en 10 Be du quartz ont pu être appliqués pour la première fois sur des sédiments marins détritiques pour déduire les vitesses d'érosion. Elles démontrent une stabilité depuis le Miocène supérieur qui implique que la mise en place de l'alternance glaciaire interglaciaire a eu un impact limité sur l'intensité de l'érosion en Himalaya.

Published
2019

23. Himalayan erosion and Ganga-Brahmaputra sediment delivery recorded in the Bengal fan from IODP Expedition 354

Author

France-Lanord, C., Galy, Albert, Huyghe, Pascale, Yoshida, Khoki, Spiess, V., Centre de Recherches Pétrographiques et Géochimiques (CRPG), Institut national des sciences de l'Univers (INSU - CNRS)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Institut des Sciences de la Terre (ISTerre), Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Shinshu University, Faculty of Science, University of Bremen, France-Lanord, Christian, and Université de Lorraine (UL)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[SDU] Sciences of the Universe [physics], [SDU.STU.TE]Sciences of the Universe [physics]/Earth Sciences/Tectonics, [SDU]Sciences of the Universe [physics], [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry, [SDU.STU.TE] Sciences of the Universe [physics]/Earth Sciences/Tectonics, [SDU.STU.GC] Sciences of the Universe [physics]/Earth Sciences/Geochemistry, [SDU.STU] Sciences of the Universe [physics]/Earth Sciences, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences
Abstract

International audience; IODP Expedition 354 in the Bengal fan [1] generated a comprehensive record of Himalayan erosion over the Neogene and Quaternary. It documents the interplay between Himalayan tectonic and the monsoon. The Bengal fan is predominantly composed of detrital sediments originating from Himalayan rivers, and transported to the N. Bengal shelf. They supply turbidity currents able to spread sediments overs 3000 km. Turbiditic record at a given site being discontinuous, Expedition 354 drilled seven sites along a 320 km E-W transect at 8°N allowing the restitution of an almost complete record of Himalayan erosion at the scale of the Neogene. In spite of the transect extension, a long absence of deposition is observed between 0.6 to 1.2 Ma indicating that turbiditic depocenter was derived more to the West for ca. 600 kyr. Bengal fan sediments have close mineralogical, geochemical and isotopic analogy with sediments of the modern Ganga-Brahmaputra rivers. Altogether they reveal mineralogical sorting associated to turbiditic transports that compares well with that of rivers in the floodplain and delta. Major and trace element geochemistry and clay compositions reveal relatively even and weak conditions of weathering throughout the 20-Ma record. Most variations are controlled by the origin of eroded sources ie. the proportions of sediments derived from Himalaya and Transhimalaya. Source tracers such as Sr-Nd isotopic compositions, and detrital carbonate compositions show organised variations with time. They also imply for some periods compositions with very high proportion of sediment derived from the Transhimalaya suggesting that the Ganga and Brahmaputra sediment delivery to the fan can be decoupled at some periods. Long term source variations imply that exposure to erosion of the different Himalayan formations has evolved as a result of the evolution of the thrusting structures. Data suggest that (1) a component derived from Transhimalayan formation was present even during Lower Miocene, (2) the Tethys Himalaya exposure to erosion was higher during Miocene than during Pliocene and Pleistocene, and (3) that the exhumation of the Lesser Himalaya was initiated around 8 Ma.

Published
2018

25. Timing and mechanism of the rise of the Shillong Plateau in the Himalayan foreland

Author

Govin, Gwladys, Najman, Yanina Manya Rachel, Copley, Alex, Millar, Ian, Van der Beek, Peter, Huyghe, Pascale, Grujic, Djordje, Davenport, Jesse, Copley, Alexander [0000-0003-0362-0494], and Apollo - University of Cambridge Repository

Subjects
37 Earth Sciences, sub-02
Abstract

Island arcs provide insights into the origin and recycling of continental crust, but questions remain concerning source metasomatism, the depth of differentiation, the potential role of amphibole fractionation, and the time scales involved. Basaltic andesites on Batan Island (Philippines) contain ≥150 Ma peridotite fragments encased in hornblendite and gabbroic rinds produced via melt-rock reaction. The peridotites have some of the lightest δ7Li and δ57Fe values yet measured in mantle rocks. These values are too fractionated to have been created solely by equilibrium partial melting and thus require a combination of melt depletion and slab fluid addition and may be derived from diffusion-modified melt channel wall rocks. Stable isotope signals are easily modified by diffusive equilibration between peridotite and host magma, so the preservation of light δ7Li and δ57Fe here suggests magma ascent rates of ∼10 km yr−1. We show that melt–wall rock reactions at ∼25–30 km depth led to the crystallization of amphibole (± plagioclase) followed by gabbroic fractionation at ∼7 km depth. The former provides a location and mechanism for the “cryptic” amphibole fractionation observed in these and perhaps many other arc lavas and may obviate the requirement for delamination of cumulates.

Published
2018
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26. Expedition 354 on the Bengal fan: Implications on Neogene erosion regime and climate

Author

France-Lanord, Christian, Spiess, Volkhard, Feakins, Sarah, Galy, Valier, Galy, Albert, Huyghe, Pascale, Yoshida, Khoki, France-Lanord, Christian, György Hetényi, Zoé Guillermin, Maud Jordan, Gerald Raymond, Shiba Subedi, Nicolas Buchs, Martin Robyr, Jean-Luc Epard, Centre de Recherches Pétrographiques et Géochimiques (CRPG), Institut national des sciences de l'Univers (INSU - CNRS)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), University of Bremen, University of Southern California (USC), Department of Marine Chemistry and Geochemistry (WHOI), Woods Hole Oceanographic Institution (WHOI), Institut des Sciences de la Terre (ISTerre), Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Shinshu University, Faculty of Science, and HKT2018 Committee

Subjects
[SDU.STU.TE]Sciences of the Universe [physics]/Earth Sciences/Tectonics, [SDU] Sciences of the Universe [physics], [SDU]Sciences of the Universe [physics], [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry, [SDU.STU.GC] Sciences of the Universe [physics]/Earth Sciences/Geochemistry, [SDU.STU.TE] Sciences of the Universe [physics]/Earth Sciences/Tectonics, [SDU.STU] Sciences of the Universe [physics]/Earth Sciences, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences
Abstract

International audience; In Himalaya, the monsoon precipitations exert a primary control on erosion. From its intensity depends the extension of the glacier cover, landslide activity, river incision, vegetation cover, and export of sediments towards the floodplain. The monsoon also exerts a primary control on the chemical erosion as weathering rates are clearly dependent upon river discharge. In the floodplain, sediment export also is tightly controlled by climate. The seasonality and intensity of the monsoon allow to reach discharge high enough to ensure the efficiency of river transport to the delta (Lupker et al. 2011). This efficient transport also acts as a limiting factor for weathering as it reduces residence time in the floodplain. The comparison between the Ganga with a large floodplain and the Brahmaputra with a narrow floodplain and comparatively lower residence time confirms that Himalayan weathering is limited by transport. Recent IODP Expedition 354 in the Bengal fan (France-Lanord et al. 2016) generated a comprehensive record of Himalayan erosion over the Neogene and Quaternary. It documents the interplay between Himalayan tectonic and climate. The Bengal fan is predominantly composed of detrital turbiditic sediments originating from Himalayan rivers, and transported through the delta and shelf canyon, supplying turbidity currents loaded with a wide spectrum of grain sizes. Turbiditic deposition makes that record at a given site is discontinuous which was the reason for an E-W transect approach. Expedition 354 drilled seven sites along a 320 km E-W transect at 8°N allowing the restitution of an almost complete record of Himalayan erosion at the scale of the Neogene. Turbiditic sediments have clear Himalayan origin and close mineralogical and isotopic analogy with those of the modern Ganga-Brahmaputra river sediments. Major and trace element geochemistry show relatively stable compositions throughout the Neogene and Quaternary. They reveal a very weak regime of chemical weathering with no significant variation through time. Concentrations in mobile elements such as Na and K relative to Al are significantly higher than in modern sediments and suggest that weathering or soil erosion is amplified in the modern time. Low weathering of the sediments at 8°N indicates that erosion was dominated by physical processes and that transport was rapid enough to prevent evolution of particles in the floodplain. In the modern Himalaya, low weathering is achieved primarily by landslides and rapid transfer through the floodplain, i.e. limited recycling of sediment deposited in the floodplain. Both processes are favoured by the seasonality and the intensity of the monsoon. On the organic side, carbon isotopic analyses of organic matter in turbidites clearly reveal its continental origin. The hydrogen isotopic composition of leaf-wax compounds reveals low δD since Early Miocene, indicative of significant amount effect i.e. Monsoon. Overall, the low weathering intensity suggests that comparable erosion regime was established since at least Early Miocene. References France-Lanord C, Spiess V, Klaus A, Schwenk T, Expedition 354 Scientists (Eds.) (2016) Proceedings of the International Ocean Discovery Program, 354. IODP.

Published
2018

27. Postseismic deformation following the April 25, 2015 Gorkha earthquake (Nepal): Afterslip versus viscous relaxation

Author

Jouanne, François, primary, Gajurel, Ananta, additional, Mugnier, Jean-Louis, additional, Bollinger, Laurent, additional, Adhikari, Lok Bijaya, additional, Koirala, Bharat, additional, Cotte, Nathalie, additional, Bhattarai, Roshanraj, additional, Pecher, Arnaud, additional, Bascou, Pascale, additional, and Huyghe, Pascale, additional

Published
2019
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28. SAGEEP 2018 papers with only a paragraph abstract

Author

Malehmir, A., primary, Pasanen, A., additional, Sims, A., additional, Brownley, Aaron, additional, Fukuda, Aaron, additional, Raef, Abdelmoneam, additional, Alhaj, Abdullah, additional, Smiarowski, Adam, additional, Aydin, Adnan, additional, Behroozmand, Ahmad-Ali, additional, Lachhab, Ahmed, additional, Hunter, Alan, additional, Morgan, Alan, additional, McClymont, Alastair, additional, Khamzin, Aleksey, additional, Cirone, Alessandro, additional, Oshkin, Alexander, additional, Saraev, Alexander, additional, Simakov, Alexander, additional, Davatzes, Alexandra, additional, Kordjazi, Alireza, additional, Liénard, Amandine, additional, Esmaeilzadeh, Amin, additional, Radjaee, Amir, additional, Collick, Amy, additional, Shober, Amy, additional, Christiansen, Anders V., additional, Pugin, Andre J. M., additional, Duncan, Andrew, additional, Katumwehe, Andrew, additional, Parsekian, Andrew, additional, Schwartz, Andrew, additional, Teeple, Andrew, additional, Konkov, Andrey, additional, Aguilar, Andrez, additional, Wagner, Anna, additional, Hantson, Anne-Lise, additional, Ebigbo, Anozie, additional, Buda, Anthony, additional, Pozdnyakova, Antonina, additional, Song, Ao, additional, Mangolds, Arnis, additional, Shlykov, Arseny, additional, Allen, Arthur, additional, Trembanis, Arthur, additional, Espana, Aubrey, additional, Devalckeneer, Aude, additional, Sullivan, Bane, additional, Dietiker, Barbara, additional, Allred, Barry, additional, Zelt, Barry, additional, Hoekstra, Bart, additional, Bloss, Benjamin, additional, Miller, Benjamin, additional, Seiderman, Benjamin, additional, Wallen, Benjamin, additional, Guillier, Bertrand, additional, Parker, Beth, additional, Jin, Biao, additional, Liu, Bin, additional, Song, Bing, additional, Wang, Bo, additional, Selfridge, Bob, additional, Pratap, Bohara, additional, Forsythe, Brandon, additional, Tober, Brandon, additional, Ewers, Brent, additional, Clark, Brian, additional, Ingamells, Brian, additional, Junck, Brian, additional, McPherson, Brian, additional, Passerella, Brian, additional, Mark, Bryan, additional, Minsley, Burke, additional, Finco, Cécile, additional, Juhlin, C., additional, Russ, Cameron, additional, Brandt, Carol, additional, Johnson, Carole, additional, DuVal, Carter, additional, SuoLiang, Chang, additional, Holzschuher, Charles, additional, Zhang, Chi, additional, Tsai, Chia-Hsing, additional, Park, Choon, additional, Bryant, Chris, additional, Linick, Chris, additional, Vogt, Christian, additional, Buckman, Christopher, additional, Yu, Chuan-tao, additional, Wang, Chuanwu, additional, Kirkendall, Clay, additional, Steelman, Colby, additional, Miazga, Colin, additional, Sweeney, Colin, additional, Armstrong, Connor, additional, Cearley, Cooper, additional, Moulton, Craig, additional, Murray, Craig, additional, Castanha, Cristina, additional, Schamper, Cyril, additional, Li, Dahu, additional, Rucker, Dale, additional, Glaser, Dan, additional, Sirota, Dana, additional, Beverly, Daniel, additional, Brown, Daniel, additional, Cook, Daniel, additional, Plotnick, Daniel, additional, Sternlicht, Daniel, additional, McPhee, Darcy, additional, Motazedian, Dariush, additional, Hall, Darrell, additional, Mortimer, Darren, additional, Hume, Dave, additional, Huntley, Dave, additional, Walsh, Dave, additional, Gunn, David, additional, Hisz, David, additional, Millar, David, additional, Redman, David, additional, Schafer, David, additional, Schieck, David, additional, Vales, David, additional, Valintine, David, additional, Wallace, David, additional, Wishart, DeBonne, additional, Keiswetter, Dean, additional, Pinkham, Derek, additional, Ntalagiannis, Dimitrios, additional, Ntarlagiannis, Dimitrios, additional, Tang, Dongchun, additional, Kutrubes, Doria, additional, Oldenburg, Douglas, additional, Thayer, Drew, additional, Robbins, Dustin, additional, Hart, Dylan, additional, Klazinga, Dylan, additional, Behrendt, E., additional, Lundberg, E., additional, Woolery, Edward, additional, Fukushima, Eiichi, additional, Goggin, Elise, additional, Menezes, Elizabeth, additional, Grunewald, Elliot, additional, Oware, Erasmus, additional, White, Eric, additional, Fischell, Erin, additional, Auken, Esben, additional, Zibulski, Eugen, additional, Torgashov, Evgeniy, additional, Zhang, F., additional, Rejiba, Fayçal, additional, Aiwekhoe, Felix, additional, Zhang, Fengkai, additional, Santos, Fernando Monteiro, additional, Kunkel, Forrest, additional, Colwell, Frederick, additional, Shubitidze, Fridon, additional, Plastow, Geoffrey, additional, Alsulaimai, Ghassan, additional, Fiandaca, Gianluca, additional, Colinet, Gilles, additional, Pope, Gina, additional, Paige, Ginger, additional, Crookston, Glenna, additional, Abrams, Greg, additional, Jorgensen, Greg, additional, Mount, Gregory, additional, Schultz, Gregory, additional, Street, Gregory, additional, Galan-Comas, Gustavo, additional, Parkin, H. Scott, additional, Nelson, Herb, additional, Liu, Haidong, additional, Yu, Haizhong, additional, Flamme, Hanna, additional, Xie, Hao, additional, Li, He, additional, Crow, Heather, additional, Speckman, Heather, additional, Willever, Heather, additional, Büsing, Henrik, additional, Yao, Hongchun, additional, Cai, Hongzhu, additional, Knox, Hunter, additional, Gottschalk, Ian Paul, additional, Shamatava, Irma, additional, Fage, Isaac, additional, Scheibz, Jürgen, additional, Park, J. Daniel, additional, Jennings, J., additional, Kaipio, J., additional, Gerhard, J.I., additional, Tronicke, J., additional, Adelson, Jordan, additional, Desmond, Jack, additional, Sheehan, Jacob, additional, Cannia, James, additional, Harris, James, additional, Hayes, James, additional, Rigby, James, additional, Simms, Janet, additional, Abraham, Jared, additional, Abraham, Jared D., additional, Payne, Jason, additional, Mugnier, Jean Louis, additional, Legault, Jean M., additional, Collet, Jean-Marie, additional, Barlow, Jeannie, additional, Abiva, Jeannine, additional, Gamey, Jeff, additional, Leberfinger, Jeffrey, additional, McKenzie, Jeffrey, additional, Munsey, Jeffrey, additional, Paine, Jeffrey, additional, Fontaine, Jeremy, additional, Pedersen, Jesper, additional, Meyer, Jessica, additional, Hu, Jiahao, additional, Sun, Jiajun, additional, Pfeiffer, Jim, additional, Keranen, Joe, additional, Ochs, Johanna, additional, Ferguson, John, additional, Herrmann, John, additional, Holt, John, additional, Jackson, John, additional, Jansen, John, additional, Kick, John, additional, Lane, John, additional, Mundell, John, additional, Miller, Jonathan, additional, Nyquist, Jonathan, additional, Wolf, Jonathan, additional, Bergstrom, Jorgen, additional, Coe, Joseph, additional, Panzik, Joseph, additional, Robinson, Judy, additional, Guillemoteau, Julien, additional, Ohan, Juliette, additional, Zhang, Jun, additional, Lee, Junghwoon, additional, Shelton, Justin, additional, Lu, Kailiang, additional, McKinley, Kate, additional, Pappas, Katherine, additional, Clark, Kathryn, additional, Decker, Kathryn, additional, Shang, Ke, additional, Sorota, Keith, additional, Maaten, Keith Van Der, additional, Enriquez, Kelly, additional, Merrill, Kelvey, additional, Maser, Ken, additional, Melton, Ken, additional, Carroll, Kenneth, additional, Williams, Kenneth, additional, Hathaway, Kent, additional, Fan, Kerui, additional, Brewer, Kevin, additional, Hon, Kevin, additional, Kingdon, Kevin, additional, Stafford, Kevin, additional, Williams, Kevin, additional, Haramy, Khamis, additional, Maharaj, Kian, additional, Davis, Kim, additional, Mwakanyamale, Kisa, additional, Tsakirmpaloglou, Konstantinos, additional, Takeuchi, Kouki, additional, Smith, Kristen, additional, Bryson, L. Sebastian, additional, Trento, L.M., additional, Ellis, Lacey, additional, Liu, Lanbo, additional, Clark, Lane, additional, Owsley, Lane, additional, He, Lanfang, additional, Golovko, Larisa, additional, Braile, Larry, additional, Lautz, Laura, additional, Sherrod, Laura, additional, Toran, Laura, additional, Beran, Laurens, additional, Slater, Lee, additional, Chen, Lei, additional, Pasion, Leonard, additional, Pozdnyakov, Lev, additional, Doyle, Liam, additional, Liu, Lichao, additional, Nie, Lichao, additional, Song, Lin-Ping, additional, Steele, Lincoln, additional, Heagy, Lindsey, additional, Madsen, Line Meldgaard, additional, Pellerin, Louise, additional, Martinez, Luis, additional, Kass, M. Andy, additional, McMaster, M., additional, Alam, MD, additional, Kymes, Madison, additional, Kotikian, Maneh, additional, Kleine, Marco de, additional, DUPREZ, Marie-Eve, additional, Carnevale, Mario, additional, Karaoulis, Marios, additional, Conradi, Mark, additional, Domaracki, Mark, additional, King, Mark, additional, Ralston, Matt, additional, Barner, Matthew, additional, Brawner, Matthew, additional, Jackson, Matthew, additional, Totten, Matthew, additional, Chapman, Melinda, additional, Best, Melvyn, additional, Bares, Michael, additional, Hendry, Michael, additional, Madcharo, Michael, additional, May, Michael, additional, Rohrer, Michael, additional, Sharer, Michael, additional, Oladunjoye, Micheal, additional, Kimball, Mindy, additional, Oyan, Mohammad Najmush Sakib, additional, Danforth, Myles, additional, Fantello, Nadia, additional, Shields, Nathaniel, additional, Eash, Neal, additional, Diamanti, Nectaria, additional, Anderson, Neil, additional, Sowko, Nicholas, additional, Stolte, Nicholas, additional, Valleau, Nick, additional, Lhomme, Nicolas, additional, Claes, Niels, additional, Ragozin, Nikita, additional, Foiged, Nikolaj, additional, Ishii, Nobuyuki, additional, Klitzsch, Norbert, additional, Ohara, Noriaki, additional, Kaufmann, Olivier, additional, Akinrinola, Omobola, additional, Koyan, P., additional, Tsourlos, P., additional, Goderniaux, Pascal, additional, Lacroix, Pascal, additional, Huyghe, Pascale, additional, Mosely, Patrick, additional, Bauman, Paul, additional, Bedrosian, Paul, additional, Schwering, Paul, additional, Wilkinson, Paul, additional, Kruiver, Pauline, additional, Pehme, Peeter, additional, Jones, Perry, additional, Annan, Peter, additional, Bobrowsky, Peter, additional, Hutchinson, Peter, additional, Zimmerman, Peter, additional, Bording, Phil, additional, Meldrum, Philip, additional, Lin, Pinrong, additional, Guo, Qian, additional, Chen, Qiang, additional, Lv, Qingtian, additional, Sangani, Radhika, additional, 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additional, Barrentine, Scottie, additional, Lane, Sean, additional, Uhlemann, Sebastian S., additional, Yang, Senlin, additional, Gravelat, Serge, additional, Evans, Shannon, additional, Kelley, Shari, additional, Johnson, Shawn, additional, Ryan, Shawn, additional, Tingle, Shawn, additional, Liu, Shengdong, additional, Ryan, Sheryl, additional, Kidanu, Shishay, additional, Yan, Shuai, additional, Zhao, Shuai, additional, Li, Shucai, additional, Brightwell, Simon, additional, Saneiyan, Sina, additional, Goliber, Sophie, additional, Phillips, Stephanie, additional, Altobelli, Stephen, additional, Billings, Stephen, additional, F., Stephen, additional, Massey, Stephen, additional, Stacy, Stephen, additional, Saville, Steve, additional, Brown, Steven, additional, Kargl, Steven, additional, Chang, Suo-liang, additional, Brantley, Susan, additional, Burns, Susan, additional, Lehtimäki, T., additional, Dismukes, Tanner, additional, Asch, Ted, additional, G-Michael, Tesfaye, additional, Asch, Theodore H., additional, Martin, Thierry, additional, Kelleners, Thijs, additional, Bell, Thomas, additional, Chauveau, Thomas, additional, Hiller, Thomas, additional, Kremer, Thomas, additional, Hansen, Thomas Mejer, additional, Sexton, Thomas, additional, Rogers, Tim, additional, Lähivaara, Timo, additional, Cartwright, Timothy, additional, Johnson, Timothy, additional, Marston, Timothy, additional, Lin, Tingting, additional, Furuya, Tom, additional, King, Tom, additional, Pallesen, Tom Martlev, additional, Endres, Tony, additional, Moraes, Tony, additional, Bach, Torben, additional, Eiskjær, Tore, additional, Morii, Toshihiro, additional, Irons, Trevor, additional, Chernov, Vadim, additional, Ignatev, Vladimir, additional, Kress, Wade, additional, Caldwell, Warren, additional, Liu, Weiqiang, additional, Wang, Weizhong, additional, Li, Wenhan, additional, Zhang, Wenyuan, additional, Brown, Wesley, additional, Trainor-Guitton, Whitney, additional, Doll, William, additional, Rowlands, William, additional, Sauck, William, additional, Seaton, William, additional, Muttashar, Wisam, additional, Xi, Xiaolu, additional, Xu, Xinji, additional, Li, Xiu, additional, Zhao, Xuefeng, additional, Benboudiaf, Yassine, additional, Meng, Yongqi, additional, Chen, Yongshun, additional, Chuangtao, Yu, additional, Han, Yu, additional, Ma, Yujia, additional, Ren, Yuxiao, additional, Mungia, Zach, additional, Liu, Zhengyu, additional, Ma, Zhenning, additional, Yang, Zhichao, additional, Jiang, Zhihai, additional, Qi, Zhipeng, additional, and Hu, Zhouwen, additional

Published
2018
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30. Onset of Rapid Exhumation in the Namche Barwa Syntaxis Constrained by Detrital Thermochronology

Author

Govin, Gwladys, Van Der Beek, Peter, Majman, Yani, Millar, Ian, Bernet, Matthias, Germignani, Lorenzo, Huyghe, Pascale, Wijbrans, Jan R., Dupont-Nivet, Guillaume, Dubigeon, Isabelle, Lancaster Environment Centre, Lancaster University, Tectonique reliefs et bassins, Institut des Sciences de la Terre (ISTerre), Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), British Geological Survey (BGS), Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), VU University Amsterdam, Free University of Amsterdam, Géosciences Rennes (GR), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR)-Centre National de la Recherche Scientifique (CNRS), Vrije Universiteit Amsterdam [Amsterdam] (VU), Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR), Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Centre National de la Recherche Scientifique (CNRS), and Vrije universiteit = Free university of Amsterdam [Amsterdam] (VU)

Subjects
[SDU.STU.TE]Sciences of the Universe [physics]/Earth Sciences/Tectonics, [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry, [SDU.STU.GC] Sciences of the Universe [physics]/Earth Sciences/Geochemistry, [SDU.STU.TE] Sciences of the Universe [physics]/Earth Sciences/Tectonics
Abstract

International audience; The Himalayan syntaxes have intrigued geoscientists for decades because of their young (~10 Ma) high-grade metamorphism and exceptionally high rates of exhumation (up to 10 mm yr-1), leading to numerous models and inferences on potential coupling between tectonic and surface processes. Several models have been proposed to explain the rapid exhumation of the eastern Namche Barwa syntaxis that invoke different controlling factors, including compressive crustal-scale folding orthogonal to the strike of the mountain belt, the subduction geometry in the indentor region, or focused fluvial incision following river capture and ensuing crustal channel flow. These models predict different times of peak metamorphism and rapid exhumation, which remain poorly constrained. Existing bedrock and detrital thermochronology studies, based on zircon fission-track (ZFT) and mica 40Ar-39Ar (Mar) dating, suggest rapid exhumation since as early as 8-10 Ma or as late as ~3 Ma. Here we report detrital ZFT, MAr and rutile U-Pb data from a newly dated composite Siwalik section located directly downstream of the syntaxis and currently constituting the most proximal detrital archive of material eroded from the syntaxis by the paleo-Siang River. We incorporate these new data together with published detrital data from the syntaxis region into a 1D version of the thermokinematic model Pecube to invert for the most probable rate of exhumation and timing of onset of rapid exhumation in the Namche Barwa syntaxis. Our results suggest onset of rapid exhumation of the syntaxis before 7 Ma, and possibly as early as ~13 Ma, at high but not extreme rates (~4 mm yr-1). In contrast to earlier modeling predictions, our best-fit model does not require exhumation rates to have slowed down over time. The detrital rutile U-Pb ages are particularly important in constraining our inverse models and we highlight the relevance of this thermochronological system for studying rapid exhumation of high-grade metamorphic massifs from the detrital record

Published
2017

31. Magneto‐chemical signature of the Lower‐to‐Middle Siwaliks transition in the Karnali River section (Western Nepal): Implications for Himalayan tectonics and climate.

Author

Gautam, Pitambar, Huyghe, Pascale, Mugnier, Jean‐Louis, and Regmi, Kamal R.

Subjects
*SOIL erosion, *PALEOMAGNETISM, *HEMATITE, *MAGNETIC susceptibility, *MAGNETIC declination, *CLIMATOLOGY, *MAGNETIC properties
Abstract

Fluviatile sediments comprising a 600‐m‐thick sequence of the Lower and Middle Siwaliks in the Karnali area in Nepal exhibit a distinct zonation revealed by magnetic and geochemical properties. Four magneto‐chemical zones (MCZ1–MCZ4), each about 150 m thick and 400 kyr in duration, provide new insights into Himalayan tectono‐climatic events during the Tortonian (Miocene) stage. They exhibit contrasting magnetic susceptibility and isothermal remanence due to differences in magnetic mineral types (magnetite, haematite, and goethite) and concentrations. Odd‐numbered zones with higher goethite/(goethite + haematite) ratio, a moisture proxy, indicate wetter conditions in the source area, while the even‐numbered zones, virtually without goethite, suggest drier conditions. Chemical indices of alteration/weathering and proxies for hydraulic sorting and mobility derived from the major element compositions also reveal contrasts among these zones. The middle of the MCZ2–MCZ3 zone, with a transitional magneto‐chemical signature, is the best candidate for the Lower‐to‐Middle Siwaliks contact, rather than the field‐based boundary placed 18 m up‐section at the base of the thick salt‐and‐pepper sandstone bed. The transition records an increase in river energy and associated accelerated erosion of the Himalayan gneiss zone as the source of coarse‐grained material. We suggest a scenario, whereby climate change from drier to wetter (with higher precipitation) conditions affects erosional processes (i.e., weathering, disaggregation and particle transport on the hillslope) prevailing in a large catchment and influencing the depositional modes. [ABSTRACT FROM AUTHOR]

Published
2020
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36. Weathering regime in the Eastern Himalaya since the mid‐Miocene: indications from detrital geochemistry and clay mineralogy of the Kameng River Section, Arunachal Pradesh, India.

Author

Vögeli, Natalie, Huyghe, Pascale, van der Beek, Peter, Najman, Yani, Garzanti, Eduardo, and Chauvel, Catherine

Subjects
*WEATHERING, *GEOCHEMISTRY, *MINERALOGY, *RIVERS
Abstract

Abstract: It is crucial to understand lateral differences in paleoclimate and weathering in order to fully understand the evolution of the Himalayan mountain belt. While many studies have focused on the western and central Himalaya, the eastern Himalaya remains poorly studied with regard to paleoclimate and past weathering history. Here, we present a multi‐proxy study on the Mio‐Pliocene sedimentary foreland‐basin section along the Kameng River in Arunachal Pradesh, northeast India, in order to obtain better insight in the weathering history of the eastern Himalaya. We analysed a continuous sedimentary record over the last 13 Ma. Heavy‐mineral and petrography data give insight into diagenesis and provenance, showing that the older part of the section is influenced by diagenesis and that sediments were not only deposited by a large Trans‐Himalayan river and the palaeo‐Kameng river, but also by smaller local tributaries. By taking into account changes in diagenesis and provenance, results of clay mineralogy and major element analysis show an overall increase in weathering intensity over time, with a remarkable change between ca. 10 and ca. 8 Ma. [ABSTRACT FROM AUTHOR]

Published
2018
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37. Significance of the clay mineral distribution in fluvial sediments of the Neogene to Recent Himalayan Foreland Basin (west-central Nepal)

Author

Huyghe, Pascale, Guilbaud, Romain, Bernet, Matthias, Galy, Albert, Gajurel, Ananta Prasad, Tectonique reliefs et bassins, Institut des Sciences de la Terre (ISTerre), Centre National de la Recherche Scientifique (CNRS)-PRES Université de Grenoble-Université Joseph Fourier - Grenoble 1 (UJF)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-PRES Université de Grenoble-Université Joseph Fourier - Grenoble 1 (UJF)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry]), Centre National de la Recherche Scientifique (CNRS)-PRES Université de Grenoble-Université Joseph Fourier - Grenoble 1 (UJF)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry]), Department of Earth Sciences [Cambridge, UK], University of Cambridge [UK] (CAM), Department of geology, Tribhuvan University, and This work was supported by the French Institut National des Sciences de l'Univers-Centre National de la Recherche Scientifique research council through the program 'ECLIPSE'.

Subjects
[SDU.STU.GM]Sciences of the Universe [physics]/Earth Sciences/Geomorphology
Abstract

International audience; Clay mineral assemblages of the Neogene Himalayan foreland basin are studied to decipher their significance with respect to tectonic and climate processes. Fluvial deposits of the Siwalik Group (west-central Nepal), and sediment of the Ganga River drainage system were analysed for clay mineralogy. The observed clay mineral assemblages are mainly composed of illite (dominant), chlorite, smectite and kaolinite. Illite and chlorite are chiefly of detrital origin, derived from Himalayan sources. Kaolinite and smectite are authigenic, and mainly developed within pore space and as coating of detrital particles. With increasing burial, diagenetic processes affected the original clay mineral signature. Illitisation of smectite and kaolinite occurred below 2500 and 3500 m depth, respectively. Therefore, illite in the lower parts of the Siwalik Group consists of a mixture of inherited illite and illitised smectite and kaolinite, as suggested by illite crystallinity. Detrital grains that make up the framework of the Siwalik Group sandstones mainly consist of quartz, feldspar and lithic fragments, which are principally of sedimentary and metamorphic origin. Lithoclast content increases over time at the expense of quartz and K-feldspar in response to uplift and erosion of the Lesser Himalaya Series since about 11-10 Ma. Despite mainly felsic source rocks, dominantly physical erosion processes in the Himalayan belt, and high-energy fluvial depositional systems, smectite is abundant in the

Published
2011

39. Dynamic ups and downs of the Himalaya

Author

Husson, Laurent, primary, Bernet, Matthias, additional, Guillot, Stéphane, additional, Huyghe, Pascale, additional, Mugnier, Jean-Louis, additional, Replumaz, Anne, additional, Robert, Xavier, additional, and Van der Beek, Peter, additional

Published
2014
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40. Late Miocene – Recent exhumation of the central Himalaya and recycling in the foreland basin assessed by apatite fission-track thermochronology of Siwalik sediments, Nepal

Author

Van Der Beek, Pieter, Robert, Xavier, Mugnier, Jean-Louis, Bernet, Matthias, Huyghe, Pascale, Labrin, Erika, Laboratoire de Géodynamique des Chaines Alpines (LGCA), Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut des Sciences de la Terre (ISTerre), Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-PRES Université de Grenoble-Institut de recherche pour le développement [IRD] : UR219-Institut national des sciences de l'Univers (INSU - CNRS)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS)-PRES Université de Grenoble-Institut de recherche pour le développement [IRD] : UR219-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR), Observatoire des Sciences de l'Univers de Grenoble [1985-2015] (OSUG [1985-2015]), Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology [2007-2019] (Grenoble INP [2007-2019])-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology [2007-2019] (Grenoble INP [2007-2019])-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut des Sciences de la Terre [2011-2015] (ISTerre [2011-2015]), Université Joseph Fourier - Grenoble 1 (UJF)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-PRES Université de Grenoble-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut de recherche pour le développement [IRD] : UR219-PRES Université de Grenoble-Centre National de la Recherche Scientifique (CNRS), and Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[SDU.STU.TE]Sciences of the Universe [physics]/Earth Sciences/Tectonics, detrital thermochronology, Nepal, [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry, Siwaliks, Himalaya, exhumation, [SDU.STU.GM]Sciences of the Universe [physics]/Earth Sciences/Geomorphology, apatite fission-track
Abstract

International audience; Thermochronological analysis of detrital sediments derived from the erosion of mountain belts and contained in the sedimentary basins surrounding them allows reconstructing the long‐term exhumation history of the sediment source areas. The effective closure temperature of the thermochronological system analysed determines the spatial and temporal resolution of the analysis through the duration of the lag time between closure of the system during exhumation and its deposition in the sedimentary basin. Here, we report apatite fission‐track (AFT) data from 31 detrital samples collected from Miocene to Pliocene stratigraphic sections of the Siwalik Group in western and central Nepal, as well as three samples from modern river sediments from the same area, that complement detrital zircon fission‐track (ZFT) and U–Pb data from the same samples presented in a companion paper. Samples from the upper part of the stratigraphic sections are unreset and retain a signal of source‐area exhumation; they show spatial variations in source‐area exhumation rates that are not picked up by the higher‐temperature systems. More deeply buried samples have been partially reset within the Siwalik basin and provide constraints on the thermal and kinematic history of the fold‐and‐thrust belt itself. The results suggest that peak source‐area exhumation rates have been constant at ∼1.8 km Myr−1 over the last ∼7 Ma in central Nepal, whereas they ranged between 1 and ∼1.5 km Myr−1 in western Nepal over the same time interval; these spatial variations may be explained by either a tectonic or climatic control on exhumation rates, or possibly a combination of the two. Increasing lag times within the uppermost part of the sections suggest an increasing component of apatites that have been recycled within the Siwalik belt and are corroborated by AFT ages of modern river sediment downstream as well as the record of the distal Bengal Fan. The most deeply buried and most strongly annealed samples record onset of exhumation of the frontal Siwaliks along the Himalayan frontal thrust at ∼2 Ma and continuous shortening at rates comparable with the present‐day shortening rates from at least 0.3 Ma onward.

Published
2006

41. Miocene to Recent exhumation of the central Himalaya determined from combined detrital zircon fission-track and U/Pb analysis of Siwalik sediments, western Nepal

Author

Bernet, Matthias, Van Der Beek, Pieter, Pik, Raphaël, Huyghe, Pascale, Mugnier, Jean-Louis, Labrin, Erika, Szulc, Adam, Laboratoire de Géodynamique des Chaines Alpines (LGCA), Observatoire des Sciences de l'Univers de Grenoble [1985-2015] (OSUG [1985-2015]), Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology [2007-2019] (Grenoble INP [2007-2019])-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology [2007-2019] (Grenoble INP [2007-2019])-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut des Sciences de la Terre [2011-2015] (ISTerre [2011-2015]), Université Joseph Fourier - Grenoble 1 (UJF)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-PRES Université de Grenoble-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut de recherche pour le développement [IRD] : UR219-PRES Université de Grenoble-Centre National de la Recherche Scientifique (CNRS), Centre de Recherches Pétrographiques et Géochimiques (CRPG), Institut national des sciences de l'Univers (INSU - CNRS)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), School of Geosciences [Edinburgh], University of Edinburgh, Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Université de Lorraine (UL)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut des Sciences de la Terre (ISTerre), Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-PRES Université de Grenoble-Institut de recherche pour le développement [IRD] : UR219-Institut national des sciences de l'Univers (INSU - CNRS)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS)-PRES Université de Grenoble-Institut de recherche pour le développement [IRD] : UR219-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR), and Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[SDU.STU.TE]Sciences of the Universe [physics]/Earth Sciences/Tectonics, Nepal, [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry, Siwaliks, U/Pb dating, Himalaya, exhumation, [SDU.STU.GM]Sciences of the Universe [physics]/Earth Sciences/Geomorphology, zircon, detrital fission-track
Abstract

International audience; Fission-track (FT) analysis of detrital zircon from synorogenic sediment is a well established tool to examine the cooling and exhumation history of convergent mountain belts, but has so far not been used to determine the long-term evolution of the central Himalaya. This study presents FT analysis of detrital zircon from 22 sandstone and modern sediment samples that were collected along three stratigraphic sections within the Miocene to Pliocene Siwalik Group, and from modern rivers, in western and central Nepal. The results provide evidence for widespread cooling in the Nepalese Himalaya at about 16.0 ± 1.4 Ma, and continuous exhumation at a rate of about 1.4 ± 0.2 km/Myr thereafter. The ~16 Ma cooling is likely related to a combination of tectonic and erosional activity, including movement on the Main Central thrust and Southern Tibetan Detachment system, as well as emplacement of the Ramgarh thrust on Lesser Himalayan sedimentary and meta-sedimentary units. The continuous exhumation signal following the ~16 Ma cooling event is seen in connection with ongoing tectonic uplift, river incision, and erosion of lower Lesser Himalayan rocks exposed below the MCT and Higher Himalayan rocks in the hanging wall of the MCT, controlled by orographic precipitation and crustal extrusion. Provenance analysis, to distinguish between Higher Himalayan and Lesser Himalayan zircon sources, is based on double dating of individual zircons with the FT and U/Pb methods. Zircons with pre-Himalayan FT cooling ages may be derived from either non-metamorphic parts of the Tethyan sedimentary succession or Higher Himalayan protolith that formerly covered the Dadeldhura and Ramgarh thrust sheets, but that have been removed by erosion. Both the Higher and Lesser Himalaya appear to be sources for the zircons that record either ~16 Ma cooling or the continuous exhumation afterwards.

Published
2006

42. C and O isotope compositions of modern fresh-water mollusc shells and river waters from Himalaya and Ganga plain

Author

Gajurel, Ananta Prasad, France-Lanord, Christian, Huyghe, Pascale, Guilmette, Caroline, Gurung, Damayanti, Laboratoire de Géodynamique des Chaines Alpines (LGCA), Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut des Sciences de la Terre (ISTerre), Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-PRES Université de Grenoble-Institut de recherche pour le développement [IRD] : UR219-Institut national des sciences de l'Univers (INSU - CNRS)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS)-PRES Université de Grenoble-Institut de recherche pour le développement [IRD] : UR219-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR), Department of geology, Tribhuvan University, Centre de Recherches Pétrographiques et Géochimiques (CRPG), Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Université de Lorraine (UL)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Observatoire des Sciences de l'Univers de Grenoble [1985-2015] (OSUG [1985-2015]), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology [2007-2019] (Grenoble INP [2007-2019])-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology [2007-2019] (Grenoble INP [2007-2019])-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut des Sciences de la Terre [2011-2015] (ISTerre [2011-2015]), and Université Joseph Fourier - Grenoble 1 (UJF)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-PRES Université de Grenoble-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut de recherche pour le développement [IRD] : UR219-PRES Université de Grenoble-Centre National de la Recherche Scientifique (CNRS)

Subjects
Ganga, seasonality, [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry, Himalaya, fresh-water molluscs, modern rivers, C and O isotopes, running water versus pond water
Abstract

The aim of this paper is to unfold the relationship between O and C isotope compositions of modern fresh-water mollusc shells and water in order to refine the basis of interpretation for paleoenvironnemental reconstruction in the sub-Himalayan river basins. Large number of mollusc shells and associated host water from both running water and closed body of water were analysed including intra-shell variability in a few cases. The O isotopic compositions of river waters in the Himalayas and Ganga plain have a large range, from -18‰ in the north of the High range up to -8 to -4 ‰ in the Ganga plain. d18O of rivers are also seasonally variable, especially in foothills rivers whereas the seasonal contrast is smoothed out for main Himalayan rivers having large catchments. O isotopic compositions of bulk shells (Aragonite) vary between -15 and -5 ‰. Average d18OAra values are consistent with precipitation at equilibrium with host waters at a temperature range of 20-25°C suggesting that shell growth may be favoured during non-monsoon conditions. Shells collected along main Himalayan rivers have d18O values uniformly distributed within -11 and -6 ‰ reflecting the minimal seasonal contrast shown by these rivers. In contrast, O isotopic compositions of shells from foothills rivers vary only by 4‰. This shows that, depending on the type of river where the molluscs grow, the information in term of d18O amplitude will be different for identical climatic conditions. In closed or pond water bodies significant enrichment in 18O due to evaporation is observed. The C isotopic compositions of river dissolved inorganic carbon (DIC) decrease downstream from 0 to -10 ‰ reflecting input of soil derived alkalinity and plant productivity in the river. d13C of shells are systematically lower than compositions calculated for equilibrium with river DIC indicating that in addition to DIC, a significant fraction of carbon is derived from metabolic sources. Intra-shell d13C are stable compared to the seasonal variability of DIC suggesting that the pool of organic carbon changes throughout year.

Published
2006

48. Enregistrement sédimentaire des déformations intraplaques : l'exemple de l'inversion structurale d'un bassin de la mer du Nord

Author

Huyghe, Pascale, Laboratoire de Géodynamique des Chaines Alpines (LGCA), Observatoire des Sciences de l'Univers de Grenoble [1985-2015] (OSUG [1985-2015]), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology [2007-2019] (Grenoble INP [2007-2019])-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology [2007-2019] (Grenoble INP [2007-2019])-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut des Sciences de la Terre [2011-2015] (ISTerre [2011-2015]), Université Joseph Fourier - Grenoble 1 (UJF)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-PRES Université de Grenoble-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut de recherche pour le développement [IRD] : UR219-PRES Université de Grenoble-Centre National de la Recherche Scientifique (CNRS), Université Joseph-Fourier - Grenoble I, Jean Louis Mugnier, Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut des Sciences de la Terre (ISTerre), Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-PRES Université de Grenoble-Institut de recherche pour le développement [IRD] : UR219-Institut national des sciences de l'Univers (INSU - CNRS)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS)-PRES Université de Grenoble-Institut de recherche pour le développement [IRD] : UR219-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR), and Talour, Pascale

Subjects
Enregistrement sédimentaire, [SDU.STU.TE]Sciences of the Universe [physics]/Earth Sciences/Tectonics, Crétacé, Mer du Nord, [SDE.MCG]Environmental Sciences/Global Changes, [SDU.STU.TE] Sciences of the Universe [physics]/Earth Sciences/Tectonics, tectonique polyphasée, sismique réflexion, décrochement, [SDE.MCG] Environmental Sciences/Global Changes, inversion structurale, défonnations intraplaques, réactivation/fracturation
Abstract

Phenomena governing the evolution of sedimentary basins and basin geometry are recorded in the stratigraphic pattern. Short term fluctuations of the accomodation space are superimposed on long term phenomena that increase the basin volume (initial stretching, effects of thermal contraction of the lithosphere and sedimentary loading). Basin evolution may then be analysed by studying sedimentary sequences and especially :1) the geometry of their boundaries (faults and unconformities) , 2) their facies, 3) their age, and 4) variations of their physical properties (radio-activity, porosity .... ). Back-stripping, differential subsidence diagrams, and geometrical methods (balanced cross-sections) allow to quantify vertical and horizontal motions of the floor of the basin. These methods were applied to the Broad Fourteens Basin (Southern North Sea) using a data base composed by 3000 km of seismic reflection profiles and around fifty wells (provided by Elf-Petroland). They show both tectonic decollement related to the distribution of salt and a complex multistage evolution principally composed of: 1) Jurassic and Lower Cretaceous syn-rift stages (basin subsidence around 1000 m during the latter) and an important uplift of the margins, 2) sinistral transpression in the Upper Cretaceous involving erosion in the basin (exceeding 3000 m in the center of the basin) and a horizontal shortening of about 10 %, 3) renewed tectonic subsidence beginning in the Miocene. Sixteen sedimentary sequences were distinguished in the Cretaceous series. Their geometty was controlled by eustatic sea level changes and tectonic motions. Contemporaneous tectonic motions are recorded in other intraplate basins and could be related to the plate kinematics around NW Europe. Major plate tectonic reorganization could be responsible for horizontal stress variations involving both reactivation of pre-existing structures in the britlle crust and lithospheric buckling., Les phénomènes qui régissent l'évolution d'un bassin sédimentaire et modifient sa géométrie laissent une empreinte dans l'organisation des dépôts. Aux phénomènes qui accroissent à long terme le volume du bassin (étirement initial, rééquilibrage thermique de la lithosphère, compensation isostasique du poids des sédiments qui se déposent) se superposent des fluctuations plus rapides de l'espace disponible. L'évolution d'un bassin peut donc être décryptée en étudiant les corps sédimentaires, et plus particulièrement: 1) la géométrie des discontinuités qui les limitent (failles et discordances), 2) les faciès qui les constituent, 3) leur âge, 4) les variations de leurs propriétés physiques (radioactivité, porosité ... ). L'utilisation des méthodes de décompaction, des diagrammes de mouvements différentiels, de substitution des structures plissées/faillées (coupes équilibrées) permet de quantifier les mouvements qui affectent le substratum du bassin. L'application de ces méthodes au Broad Fourteens Basin (Sud de la Mer du Nord), à partir d'une base de données constituée par 3000 km de sismique réflexion et une cinquantaine de puits (consultée grâce à Elf-Petroland) a mis en évidence une histoire polyphasée complexe, affectant une couverture décollée de son socle. Cette histoire est composée principalement : 1) d'une extension jurassique, puis 2) d'une extension crétacé inférieur avec une subsidence dans le bassin d'environ 1000 m et une importante surrection initiale des marges, 3) d'une compression avec une composante décrochante sénestre au Crétacé supérieur le long des failles de bordure orientées N160° ; elle a induit une érosion du centre du bassin de plus de 3000 m, et un raccourcissement horizontai de l'ordre de 10 %, 4) d'une extension néogène plus limitée. Une analyse détaillée a permis de mettre en évidence seize unités sédimentaires retraçant les mouvements tectoniques et les fluctuations relatives du niveau de la mer au Crétacé dans le bassin. Des corrélations temporelles entre le Broad Fourteens Basin, d'autres bassins intraplaques et la cinématique des plaques aux pourtours de l'Europe de l'Ouest semblent envisageables. La réorganisation des plaques mondiales paraît être à l'origine de variations horizontales des contraintes intraplaques, qui induisent à la fois des réactivations d'accidents préexistants de la croûte fragile et des mouvements verticaux (flambage) de la lithosphère.

Published
1992

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